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Sample records for tetranuclear copper complexes

  1. Syntheses, crystal structures, and physical properties of dinuclear copper(I) and tetranuclear mixed-valence copper(I,II) complexes with hydroxylated bipyridyl-like ligands.

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    Zhang, Xian-Ming; Tong, Ming-Liang; Gong, Meng-Lian; Lee, Hung-Kay; Luo, Li; Li, King-Fai; Tong, Ye-Xiang; Chen, Xiao-Ming

    2002-07-15

    Four copper complexes with hydroxylated bipyridyl-like ligands, namely [Cu(2)(ophen)(2)] (1), [Cu(4)(ophen)(4)(tp)] (2), [Cu(4)(obpy)(4)(tp)] (3), and [Cu(4)(obpy)(4)(dpdc)].2H(2)O (4), (Hophen=2-hydroxy-1,10-phenanthroline, Hobpy=6-hydroxy-2,2'-bipyridine, tp=terephthalate, dpdc=diphenyl-4,4'-dicarboxylate) have been synthesized hydrothermally. X-ray single-crystal structural analyses of these complexes reveal that 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy) ligands are hydroxylated into ophen or obpy during the reaction, which provides structural evidence for the long-time argued Gillard mechanism. The dinuclear copper(I) complex 1 has three supramolecular isomers in the solid state, in which short copper-copper distances (2.66-2.68 A) indicate weak metal-metal bonding interactions. Each of the mixed-valence copper(i,ii) complexes 2-4 consists of a pair of [Cu(2)(ophen)(2)](+) or [Cu(2)(obpy)(2)](+) fragments bridged by a dicarboxylate ligand into a neutral tetranuclear dumbbell structure. Dinuclear 1 is an intermediate in the formation of 2 and can be converted into 2 in the presence of additional copper(II) salt and tp ligands under hydrothermal conditions. In addition to the ophen-centered pi-->pi* excited-state emission, 1 shows strong emissions at ambient temperature, which may be tentatively assigned as an admixture of copper-centered d-->s,p and MLCT excited states.

  2. A bright tetranuclear iridium(III) complex.

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    Baranoff, Etienne; Orselli, Enrico; Allouche, Lionel; Di Censo, Davide; Scopelliti, Rosario; Grätzel, Michael; Nazeeruddin, Md Khaja

    2011-03-14

    A cyclic tetranuclear cyclometallated iridium(III) complex using cyanide anions as bridging ligands and displaying a tetrahedrally distorted square geometry has been obtained with high yield; photo- and electrochemical characterizations show that most interesting properties of mononuclear cyclometallated iridium complexes are retained in the tetranuclear assembly.

  3. Tetranuclear copper(ii)-Schiff-base complexes as active catalysts for oxidation of cyclohexane and toluene.

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    Roy, Partha; Manassero, Mario

    2010-02-14

    Three new Cu(ii) complexes, [Cu(4)(O)(L(n))(2)(CH(3)COO)(4)] where HL(1) = 4-methyl-2,6-bis(2-fluoroethyliminomethyl) phenol for complex , HL(2) = 4-methyl-2,6-bis(2-chloroethyliminomethyl) phenol for complex .0.25CH(3)CN and HL(3) = 4-methyl-2,6-bis(2-bromoethyliminomethyl) phenol for complex have been synthesized and characterized by elemental analysis, FTIR, UV-vis spectroscopy, and electrospray ionization mass spectroscopy. The structure of complex .0.25CH(3)CN has also been confirmed by single crystal X-ray diffraction analysis. These complexes have been found to be active catalysts for the oxidation of cyclohexane and toluene in the presence of hydrogen peroxide as the oxidant under mild conditions. Cyclohexane is oxidized to yield cyclohexanol and cyclohexanone, whereas toluene is oxidized to benzyl alcohol and benzaldehyde.

  4. Synthesis, structure characterization, DNA binding, and cleavage properties of mononuclear and tetranuclear cluster of copper(II) complexes.

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    Vafazadeh, Rasoul; Hasanzade, Naime; Heidari, Mohammad Mehdi; Willis, Anthony C

    2015-01-01

    Two copper(II) complexes, cluster 1, and mononuclear 2, have been synthesized by reacting acetylacetone and benzohydrazide (1:1 ratio for 1 and 1:2 ratio for 2) with CuCl(2) in a methanol solution. In 2, which is a new complex, the ligand acts as a tetradentate which binds the metal ion via two amide-O atoms and two imine-N atoms providing an N(2)O(2) square-planar around the copper(II) ion. The absorption spectra data evidence strongly suggested that the two copper(II) compounds could interact with CT-DNA (intrinsic binding constant, K(b) = 0.45×10(4) M-1 for 1 and K(b) = 2.39×10(4) M-1 for 2). The super coiled plasmid pBR322 DNA cleavage ability was studied with 1 and 2 in the presence and absence of H(2)O(2) as an oxidant. In both the absence and the presence of an oxidizing agent, complex 2 exhibited no nuclease activity. However, even in the absence of an oxidant, complex 1 exhibited significant DNA cleavage activity.

  5. New cyclic tetranuclear copper(II) complexes containing quadrilateral cores: Synthesis, structure, spectroscopy and their interactions with DNA in aqueous solution

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    Giri, Gopal C.; Haldar, Shobhraj; Ghosh, Aloke Kumar; Chowdhury, Priyanka; Carrella, Luca; Ghosh, Utpal; Bera, Manindranath

    2017-08-01

    Three new cyclic tetranuclear copper(II) complexes, Tetrakis{3-[(2-pyridylmethyl)-amino]-propionato}(tetrachloro)tetracopper(II)methanolhydrate (1·CH3OH·H2O), Tetrakis{3-[(2-pyridylmethyl)-amino]-propionato}(tetrathiocyanato)tetracopper(II) (2) and Tetrakis{3-[(2-pyridylmethyl)-amino]-propionato}(tetraazido)tetracopper(II) (3) have been synthesized by exploiting the chelating ability and bridging potential of a carboxyamine functionalized tridentate ligand, HL (HL = 3-[(2-Pyridylmethyl)-amino]-propionic acid). Complexes 1, 2 and 3 have been synthesized by carrying out reaction of the ligand HL with stoichiometric amounts of CuCl2·2H2O, CuCl2·2H2O/NH4SCN, and CuCl2·2H2O/NaN3, respectively, in the presence of NMe4OH at ambient temperature. Various analytical techniques have been employed to characterize the complexes, including single crystal X-ray diffraction study of 1. Structures of complexes 2 and 3 have been optimized by DFT calculation at B3LYP/6-311G level. Analysis of X-ray crystal structure reveals that the metallic core of complex 1 contains four distorted square pyramidal Cu(II) ions. The Cu(II) ions in each complex are arranged at the corners of a quadrilateral showing a μ2:η1:η1syn-anti bidentate bridging mode of four carboxylate groups of L- ligands with each bridging between two Cu(II) ions. These complexes represent a new family of 16-MCCuII-4 metallocoronates with repeating -[CuIIsbnd Osbnd Csbnd O]- units. In aqueous solution (pH∼7.5), the interactions of complexes with DNA have been investigated by UV-Vis and fluorescence titration spectroscopy, and viscosity measurements.

  6. A unique discrete tetranuclear Cu'-Cu(N-N)2Cu-Cu' copper(II) complex, built from a μ3-1,2,4-triazolato-μ-carboxylato ligand, as an effective DNA cleavage agent.

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    Hernández-Gil, Javier; Ferrer, Sacramento; Castiñeiras, Alfonso; Lloret, Francesc

    2012-09-17

    The title compound, characterized by means of an X-ray structure analysis, represents an easy example of a noncatena "1 + 2 + 1" tetranuclear copper(II) μ(3)-triazolate compound. [Cu(4)(atc)(2)(dien)(4)(ClO(4))(2)](ClO(4))(2)·2H(2)O (1), where H(2)atc = 5-amino-l,2,4-triazole-3-carboxylic acid and dien = diethylenetriamine = 1,4,7-triazaheptane, contains two copper atoms linked by a double diazinic bridge, each of which is further connected to a third and fourth copper atom (Cu') through the triply bridging triazolato ring and the bidentate carboxylato group of the atc(2-) ligands. The copper-copper distances within the tetranuclear unit are Cu-Cu = 4.059 Å, Cu-Cu' = 5.686 and 6.370 Å, and Cu'-Cu' = 11.373 Å. The compound self-assembles into a tridimensional hydrogen-bonded network to generate a MOF. 1 exhibits antiferromagnetic behavior with g = 2.10(1), J = -34.1(2) cm(-1) and j = -5.50(3) cm(-1), where J is the coupling constant of the central Cu-Cu pair and j the coupling constant of the two Cu-Cu' (Cu(central)-Cu(pheripheral)) pairs, as defined by H = -JS(2)S(2a) - j (S(1)S(2) + S(2a)S(1a)). Complex 1 has been tested as nuclease mimic. It shows good binding propensity to calf thymus DNA, with a binding constant value of 6.20 × 10(6) M(-1) (K(app)) and ΔT(m) = 18.3 °C. Moreover, the compound displays efficient oxidative cleavage of pUC18 DNA, even at low concentration, in the presence of a mild reducing agent (ascorbate), with a rate constant for the conversion of supercoiled to nicked DNA (k(obs)) of ~0.126 min(-1). The good reactivity of 1 toward DNA is explained from the electrostatic interactions of the cationic species produced in solution.

  7. Tetranuclear zinc(II-oxy (benzothiazole-2-thiolate aggregate and copper(I phenylthiolate aggregate

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    Abir Goswami

    2015-12-01

    Full Text Available A tetranuclear zinc-oxy (benzothiazole-2-thiolate aggregate whose structure has a C3-axis passing through ZnO unit relating three other zinc ions and a tetranuclear copper(I phenylthiolate aggregate having each thiphenolate ligand bridging three copper ions are reported. These aggregates were prepared by hydrothermal reactions of 2,2′-dithiobis-(benzothiazole with zinc nitrate or copper(I iodide, respectively. The reaction of zinc nitrate passed through in situ abstraction of a oxy ligand from moisture to form a Zn4O core holding six 2-benzothiazolethiolate ligands, and during the formation of the aggregate, cleavage of S–S bond of 2,2′-dithiobis-(benzothiazole took place. Whereas, an aggregate formed by self-assembling of copper(I phenylthiolate was formed after extensive degradation of 2,2′-dithiobis-(benzothiazole during solvothermal reaction.

  8. Syntheses, crystal structures, magnetic properties, and EPR spectra of tetranuclear copper(II) complexes featuring pairs of "roof-shaped" Cu2X2 dimers with hydroxide, methoxide, and azide bridges.

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    Graham, B; Hearn, M T; Junk, P C; Kepert, C M; Mabbs, F E; Moubaraki, B; Murray, K S; Spiccia, L

    2001-03-26

    Hydroxo- and methoxo-bridged tetranuclear copper(II) complexes of the tetramacrocyclic ligand 1,2,4,5-tetrakis(1,4,7-triazacyclonon-1-ylmethyl)benzene (Ldur), have been prepared from [Cu4Ldur(H2O)8](ClO4)8.9H2O (1). Addition of base to an aqueous solution of 1 gave [Cu4Ldur(mu2-OH)4](ClO4)4 (2). Diffusion of MeOH into a DMF solution of 2 produces [Cu4Ldur(mu2-OMe)4](ClO4)4.HClO4.2/3MeOH (3), a complex which hydrolyzes on exposure to moisture regenerating 2. The structurally related azido-bridged complex, [Cu4Ldur(mu2-N3)4](PF6)4.4H2O.6CH3CN (4), was produced by reaction of Ldur with 4 molar equiv of Cu(OAc)2.H2O and NaN3 in the presence of excess KPF6. Compounds 2-4 crystallize in the triclinic space group P1 (No. 2) with a = 10.248(1) A, b = 12.130(2) A, c = 14.353(2) A, alpha = 82.23(1) degrees, beta = 80.79(1) degrees, gamma = 65.71(1) degrees, and Z = 1 for 2, a = 10.2985(4) A, b = 12.1182(4) A, c = 13.9705(3) A, alpha = 89.978(2) degrees, beta = 82.038(2) degrees, gamma = 65.095(2) degrees, and Z = 1 for 3, and a = 12.059(2) A, b = 12.554(2) A, c = 14.051(2) A, alpha = 91.85(1) degrees, beta = 98.22(1) degrees, gamma = 105.62(1) degrees, and Z = 1 for 4. The complexes feature pairs of isolated dibridged copper(II) dimers with "roof-shaped" Cu2(mu2-X)2 cores (X = OH-, OMe-, N3-), as indicated by the dihedral angle between the two CuX2 planes (159 degrees for 2, 161 degrees for 3, and 153 degrees for 4). This leads to Cu.Cu distances of 2.940(4) A for 2, 2.962(1) A for 3, and 3.006(5) A for 4. Variable-temperature magnetic susceptibility measurements indicate weak antiferromagnetic coupling (J = -27 cm(-1)) for the hydroxo-bridged copper(II) centers in 2 and very strong antiferromagnetic coupling (J = -269 cm(-1)) for the methoxo-bridged copper(II) centers in 3. Pairs of copper(II) centers in 4 display the strongest ferromagnetic interaction (J = 94 cm(-1)) reported thus far for bis(mu2-1,1-azido)-bridged dicopper units. Spectral measurements on a neat powdered

  9. A stable luminescent hybrid mesoporous copper complex-silica.

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    Rico, Marisa; Sepúlveda, Angel E; Ruiz, Santiago; Serrano, Elena; Berenguer, Jesús R; Lalinde, Elena; Garcia-Martinez, Javier

    2012-09-14

    Surfactant-assisted co-condensation of an emissive tetranuclear alkynyl-phosphine copper cluster with TEOS affords a hydrothermally stable blue-emitter mesoporous hybrid metal complex-silica material.

  10. Heterobridged dinuclear, tetranuclear, dinuclear-based 1-d, and heptanuclear-based 1-D complexes of copper(II) derived from a dinucleating ligand: syntheses, structures, magnetochemistry, spectroscopy, and catecholase activity.

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    Majumder, Samit; Sarkar, Sohini; Sasmal, Sujit; Sañudo, E Carolina; Mohanta, Sasankasekhar

    2011-08-15

    The work in this paper presents syntheses, characterization, crystal structures, variable-temperature/field magnetic properties, catecholase activity, and electrospray ionization mass spectroscopic (ESI-MS positive) study of five copper(II) complexes of composition [Cu(II)(2)L(μ(1,1)-NO(3))(H(2)O)(NO(3))](NO(3)) (1), [{Cu(II)(2)L(μ-OH)(H(2)O)}(μ-ClO(4))](n)(ClO(4))(n) (2), [{Cu(II)(2)L(NCS)(2)}(μ(1,3)-NCS)](n) (3), [{Cu(II)(2)L(μ(1,1)-N(3))(ClO(4))}(2)(μ(1,3)-N(3))(2)] (4), and [{Cu(II)(2)L(μ-OH)}{Cu(II)(2)L(μ(1,1)-N(3))}{Cu(II)(μ(1,1)-N(3))(4)(dmf)}{Cu(II)(2)(μ(1,1)-N(3))(2)(N(3))(4)}](n)·ndmf (5), derived from a new compartmental ligand 2,6-bis[N-(2-pyridylethyl)formidoyl]-4-ethylphenol, which is the 1:2 condensation product of 4-ethyl-2,6-diformylphenol and 2-(2-aminoethyl)pyridine. The title compounds are either of the following nuclearities/topologies: dinuclear (1), dinuclear-based one-dimensional (2 and 3), tetranuclear (4), and heptanuclear-based one-dimensional (5). The bridging moieties in 1-5 are as follows: μ-phenoxo-μ(1,1)-nitrate (1), μ-phenoxo-μ-hydroxo and μ-perchlorate (2), μ-phenoxo and μ(1,3)-thiocyanate (3), μ-phenoxo-μ(1,1)-azide and μ(1,3)-azide (4), μ-phenoxo-μ-hydroxo, μ-phenoxo-μ(1,1)-azide, and μ(1,1)-azide (5). All the five compounds exhibit overall antiferromagnetic interaction. The J values in 1-4 have been determined (-135 cm(-1) for 1, -298 cm(-1) for 2, -105 cm(-1) for 3, -119.5 cm(-1) for 4). The pairwise interactions in 5 have been evaluated qualitatively to result in S(T) = 3/2 spin ground state, which has been verified by magnetization experiment. Utilizing 3,5-di-tert-butyl catechol (3,5-DTBCH(2)) as the substrate, catecholase activity of all the five complexes have been checked. While 1 and 3 are inactive, complexes 2, 4, and 5 show catecholase activity with turn over numbers 39 h(-1) (for 2), 40 h(-1) (for 4), and 48 h(-1) (for 5) in dmf and 167 h(-1) (for 2) and 215 h(-1) (for 4) in acetonitrile

  11. Di-, tri-, and tetranuclear nickel(II) complexes with oximato bridges: magnetism and catecholase-like activity of two tetranuclear complexes possessing rhombic topology.

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    Das, Lakshmi Kanta; Biswas, Apurba; Kinyon, Jared S; Dalal, Naresh S; Zhou, Haidong; Ghosh, Ashutosh

    2013-10-21

    Oxime-based tridentate Schiff base ligands 3-[2-(diethylamino)ethylimino]butan-2-one oxime (HL(1)) and 3-[3-(dimethylamino)propylimino]butan-2-one oxime (HL(2)) produced the dinuclear complex [Ni2L(1)2](ClO4)2 (1) and trinuclear complex [Ni3(HL(2))3(μ3-O)](ClO4)4·CH3CN (2), respectively, upon reaction with Ni(ClO4)2·6H2O. However, in a slightly alkaline medium, both of the ligands underwent hydrolysis and resulted in tetranuclear complexes [{Ni(deen)(H2O)}2(μ3-OH)2{Ni2(moda)4}](ClO4)2·2CH3CN (3) and [{Ni(dmpn)(CH3CN)2}2(μ3-OH)2{Ni2(moda)4}](ClO4)2·CH3CN (4), where deen = 2-(diethylamino)ethylamine, dmpn = 3-(dimethylamino)-1-propylamine, and modaH = diacetyl monoxime. All four complexes have been structurally characterized. Complex 1 is a centrosymmetric dimer where the square planar nickel(II) atoms are joined solely by the oximato bridges. In complex 2, three square planar nickel atoms form a triangular core through a central oxido (μ3-O) and peripheral oximato bridges. Tetranuclear complexes 3 and 4 consist of four distorted octahedral nickel(II) ions held together in a rhombic chair arrangement by two central μ3-OH and four peripheral oximato bridges. Magnetic susceptibility measurements indicated that dinuclear 1 and trinuclear 2 exhibited diamagnetic behavior, while tetranuclear complexes 3 and 4 were found to have dominant antiferromagnetic intramolecular coupling with concomitant ferromagnetic interactions. Despite its singlet ground state, both 3 and 4 serve as useful examples of Kahn's model for competing spin interactions. High-frequency EPR studies were also attempted, but no signal was detected, likely due to the large energy gap between the ground and first excited state. Complexes 3 and 4 exhibited excellent catecholase-like activity in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone, whereas 1 and 2 did not show such catalytic activity. Kinetic data analyses of this oxidation reaction in acetonitrile

  12. Mononuclear and tetranuclear Fe(III) complexes with two different types of N, O donor Schiff base ligands

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    Sutradhar, Manas; Roy Barman, Tannistha; Drew, Michael G. B.; Rentschler, Eva

    2013-06-01

    A mononuclear Fe(III) complex of a tetradentate N2O2 donor Schiff base ligand derived from 3-ethoxysalicaldehyde and ethylenediamine has been reported. In addition two tetranuclear Fe(III) complexes with discrete Fe4III(μ4-O) cores have been synthesized and characterized using two Schiff base ligands (H2L1-2) derived from two different aromatic acid hydrazides and diacetyl monoxime. The mononuclear Fe(III) and one of the tetranuclear Fe(III) complexes have been structurally characterized by single-crystal X-ray crystallography. The mononuclear complex has a highly distorted octahedral geometry. The tetranuclear Fe(III) complexes are found to be rare examples with discrete neutral alkoxido-oxido clusters with Fe4III(μ4-O) cores.

  13. Copper Sensing Function of Drosophila Metal-Responsive Transcription Factor-1 Is Mediated By a Tetranuclear Cu(I) Cluster

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    Chen, X.; Hua, H.; Balamurugan, K.; Kong, X.; Zhang, L.; George, G.N.; Georgiev, O.; Schaffner, W.; Giedroc, D.P.

    2009-05-12

    Drosophila melanogaster MTF-1 (dMTF-1) is a copper-responsive transcriptional activator that mediates resistance to Cu, as well as Zn and Cd. Here, we characterize a novel cysteine-rich domain which is crucial for sensing excess intracellular copper by dMTF-1. Transgenic flies expressing mutant dMTF-1 containing alanine substitutions of two, four or six cysteine residues within the sequence {sup 547}CNCTNCKCDQTKSCHGGDC{sup 565} are significantly or completely impaired in their ability to protect flies from copper toxicity and fail to up-regulate MtnA (metallothionein) expression in response to excess Cu. In contrast, these flies exhibit wild-type survival in response to copper deprivation thus revealing that the cysteine cluster domain is required only for sensing Cu load by dMTF-1. Parallel studies show that the isolated cysteine cluster domain is required to protect a copper-sensitive S. cerevisiae ace1 strain from copper toxicity. Cu(I) ligation by a Cys-rich domain peptide fragment drives the cooperative assembly of a polydentate [Cu{sub 4}-S{sub 6}] cage structure, characterized by a core of trigonally S{sub 3} coordinated Cu(I) ions bound by bridging thiolate ligands. While reminiscent of Cu{sub 4}-L{sub 6} (L = ligand) tetranuclear clusters in copper regulatory transcription factors of yeast, the absence of significant sequence homology is consistent with convergent evolution of a sensing strategy particularly well suited for Cu(I).

  14. Solvent-controlled synthesis of tetranuclear cage-like copper(II) silsesquioxanes. Remarkable features of the cage structures and their high catalytic activity in oxidation with peroxides.

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    Dronova, Marina S; Bilyachenko, Alexey N; Yalymov, Alexey I; Kozlov, Yuriy N; Shul'pina, Lidia S; Korlyukov, Alexander A; Arkhipov, Dmitry E; Levitsky, Mikhail M; Shubina, Elena S; Shul'pin, Georgiy B

    2014-01-14

    Two principally different in their molecular architecture isomeric tetranuclear copper(ii) silsesquioxanes, "Globule"-like compound [(PhSiO1.5)12(CuO)4(NaO0.5)4] (1) and "Sandwich"-like derivative [(PhSiO1.5)6(CuO)4(NaO0.5)4(PhSiO1.5)6] (2), were synthesized by the partial cleavage of polymeric copper(ii) silsesquioxane [(PhSiO1.5)2(CuO)]n by tetraphenylcyclotetrasiloxanolate. The route leading to the formation of either 1 or 2 entirely depends on the nature and composition of the solvent used for this reaction. Thus, the process in an ethanol-1-butanol solution gives compound 1. When a 1,4-dioxane-methanol mixture was used, compound 2 was prepared. The structures and unusual crystal packing of the cages were confirmed by the X-ray studies. It has been found that the reaction of benzene with H2O2 in acetonitrile solution at 50 °C catalyzed by 1 requires addition of trifluoroacetic acid (TFA) in low concentration and gives phenol with a turnover number (TON) of 250 after 3 h. The initial reaction rate W0 linearly depends on the concentration of catalyst 2. The oxidation of 1-phenylethanol to acetophenone with hydrogen peroxide catalyzed by complex 1 in the presence of TFA is not efficient. In contrast, 1 exhibited excellent activity in the oxidation with tert-butyl hydroperoxide (TBHP) in the absence of any acid (the yield of acetophenone was close to the quantitative, TON attained 475 after 2 h). A kinetic study of this reaction led to the conclusion that the process occurs with the participation of radicals tert-BuO˙ produced in the Cu-promoted decomposition of TBHP. The mode of dependence of W0 on the initial concentration of TBHP indicates the formation of an intermediate adduct between the catalyst 1 and TBHP (characterized by the equilibrium constant K1≈ 2 M(-1) for the conditions of conducted experiments) followed by subsequent decomposition of the adduct (k2≈ 0.2 s(-1)) to generate an intermediate species tert-BuO˙ which induces the alcohol oxidation.

  15. Rhombus-shaped tetranuclear [Ln4] complexes [Ln = Dy(III) and Ho(III)]: synthesis, structure, and SMM behavior.

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    Chandrasekhar, Vadapalli; Hossain, Sakiat; Das, Sourav; Biswas, Sourav; Sutter, Jean-Pascal

    2013-06-03

    The reaction of a new hexadentate Schiff base hydrazide ligand (LH3) with rare earth(III) chloride salts in the presence of triethylamine as the base afforded two planar tetranuclear neutral complexes: [{(LH)2Dy4}(μ2-O)4](H2O)8·2CH3OH·8H2O (1) and [{(LH)2Ho4}(μ2-O)4](H2O)8·6CH3OH·4H2O (2). These neutral complexes possess a structure in which all of the lanthanide ions and the donor atoms of the ligand remain in a perfect plane. Each doubly deprotonated ligand holds two Ln(III) ions in its two distinct chelating coordination pockets to form [LH(Ln)2](4+) units. Two such units are connected by four [μ2-O](2-) ligands to form a planar tetranuclear assembly with an Ln(III)4 core that possesses a rhombus-shaped structure. Detailed static and dynamic magnetic analysis of 1 and 2 revealed single-molecule magnet (SMM) behavior for complex 1. A peculiar feature of the χM" versus temperature curve is that two peaks that are frequency-dependent are revealed, indicating the occurrence of two relaxation processes that lead to two energy barriers (16.8 and 54.2 K) and time constants (τ0 = 1.4 × 10(-6) s, τ0 = 7.2 × 10(-7) s). This was related to the presence of two distinct geometrical sites for Dy(III) in complex 1.

  16. Structural and magnetic characterization of three tetranuclear Cu(II) complexes with face-sharing-dicubane/double-open-cubane like core framework

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    Paul, Aparup; Bertolasi, Valerio; Figuerola, Albert; Manna, Subal Chandra

    2017-05-01

    Three novel tetranuclear copper(II) complexes namely [Cu4(L1)4]•2(dmf) (1), [Cu4(L1)4] (2) and [Cu4(L2)2(HL2)2(H2O)2]•2(ClO4)·6(H2O) (3) (H2L1, (E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol; H2L2, (E)-2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol)) were synthesized from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligands. The structural determination reveals that complex 1 crystallizes in the monoclinic system with space group C2/c, whereas both the complexes 2 and 3 crystallize in the triclinic system with space group P-1. Complexes 1 and 2 possess face-sharing dicubane core, on the other hand complex 3 has double open cubane core structure. The copper(II) ions in the cubane core are in distorted square planar geometries, and weak π…π and C-H…π interactions lead to formation of a 2D supramolecular architecture for complexes 1 and 2. At room temperature complexes 1, 2 and 3, exhibit fluorescence with a quantum yield (Φs) of 0.47, 0.49 and 0.38, respectively. Variable temperature magnetic susceptibility measurements in the range 2-300 K indicate an overall weak antiferromagnetic exchange coupling in all complexes. The PHI program was used to study their magnetic behaviour. In agreement with their face-sharing dicubane structure, a Hamiltonian of the type H =- J1(S1S2+S1S2'+S1'S2+S1'S2') - J2S1S1', where S1 = S1' = S2 = S2' = SCu =1/2, was used for studying complexes 1 and 2. Simulations performed suggest magnetic exchange constants with values close to J1 =-20 cm-1 and J2 =0 cm-1 for these complexes. On the other hand, the spin Hamiltonian H =- J1(S1S4+S2S3) - J2(S1S3+S2S4) - J3S1S2, where S1 = S2 = S3 = S4 = SCu =1/2, was used to study the magnetic behaviour of the double open cubane core of complex 3 and a good agreement between the experimental and simulated results was found by using the parameters g1 = g2 =2.20, g3 = g4 =2.18, J1 =-36 cm-1, J2 =-44 cm-1 and J3 =0 cm-1.

  17. DINUCLEAR COMPLEXES AS BUILDING BLOCKS FOR TETRA-NUCLEAR MACROCYCLIC COMPLEXES WITH DITHIOLATE MACROCYCLIC LIGAND

    Directory of Open Access Journals (Sweden)

    V. Lozan

    2013-06-01

    Full Text Available A series of novel tri-, tetra- and pentanuclear complexes composed of dinuclear LM units (M=Co, Ni, Zn; L=24-membered macrocyclic hexaaza-dithiophenolate ligand and ferrocenecarboxylate ([CpFeC5H4CO2]ˉ, 1,1’-ferrocenedicarboxy-late ([Fe(C5H4-CO22]2ˉ, acetylene-dicarboxylate, terephthalate, isophthalate, and naphthalene diimide dicarboxylate groups is reported. The complexes, have been synthesized and characterised by UV/Vis-, IR-, NMR-spectroscopy, Cyclovoltammetry, and X-ray crystallography. Each dicarboxylate dianion acts as a quadridentate bridging ligand linking two bioctahedral LM2 units via µ1,3-bridging carboxylate functions to generate discrete dications with a central LM2(O2C-R-CO2M2L core. The magnetic properties of these compounds reveal the presence of weak ferromagnetic exchange interactions between the NiII ions of the dinuclear subunits and negligible coupling across the dicarboxylate bridges.

  18. Copper complexes as chemical nucleases

    Indian Academy of Sciences (India)

    Keywords. Copper(II) complexes; nuclease activity; catalytic properties; DNA binding. Abstract. Redox active mononuclear and binuclear copper(II) complexes have been prepared and structurally characterized. ... The cleavage activity of the bis-dpq complex is significantly higher than the bis-phen complex of copper(II).

  19. Structural and magnetic characterization of three tetranuclear Cu(II) complexes with face-sharing-dicubane/double-open-cubane like core framework

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Aparup [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721102, West Bengal (India); Bertolasi, Valerio [Dipartimento di Scienze Chimiche e Farmaceutiche, Centro di Strutturistica Diffrattometrica, Università di Ferrara, Via L. Borsari, 46, 44100 Ferrara (Italy); Figuerola, Albert [Departament de Química Inorgànica i Orgànica (Secció de Química Inorgànica) and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Manna, Subal Chandra, E-mail: scmanna@mail.vidyasagar.ac.in [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721102, West Bengal (India)

    2017-05-15

    Three novel tetranuclear copper(II) complexes namely [Cu{sub 4}(L{sup 1}){sub 4}]∙2(dmf) (1), [Cu{sub 4}(L{sup 1}){sub 4}] (2) and [Cu{sub 4}(L{sup 2}){sub 2}(HL{sup 2}){sub 2}(H{sub 2}O){sub 2}]∙2(ClO{sub 4})·6(H{sub 2}O) (3) (H{sub 2}L{sup 1}, (E)−2-((1-hydroxybutan-2-ylimino)methyl)phenol; H{sub 2}L{sup 2}, (E)−2-((1-hydroxybutan-2-ylimino)methyl)−6-methoxyphenol)) were synthesized from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligands. The structural determination reveals that crystallizes in the monoclinic system with space group C2/c, whereas both the and crystallize in the triclinic system with space group P-1. and possess face-sharing dicubane core, on the other hand complex 3 has double open cubane core structure. The copper(II) ions in the cubane core are in distorted square planar geometries, and weak π…π and C–H…π interactions lead to formation of a 2D supramolecular architecture for and . At room temperature and , exhibit fluorescence with a quantum yield (Φ{sub s}) of 0.47, 0.49 and 0.38, respectively. Variable temperature magnetic susceptibility measurements in the range 2–300 K indicate an overall weak antiferromagnetic exchange coupling in all complexes. The PHI program was used to study their magnetic behaviour. In agreement with their face-sharing dicubane structure, a Hamiltonian of the type H =– J{sub 1}(S{sub 1}S{sub 2}+S{sub 1}S{sub 2’}+S{sub 1'}S{sub 2}+S{sub 1'}S{sub 2’}) – J{sub 2}S{sub 1}S{sub 1’}, where S{sub 1} = S{sub 1’} = S{sub 2} = S{sub 2’} = S{sub Cu} =1/2, was used for studying and . Simulations performed suggest magnetic exchange constants with values close to J{sub 1} =−20 cm{sup −1} and J{sub 2} =0 cm{sup -1} for these complexes. On the other hand, the spin Hamiltonian H =– J{sub 1}(S{sub 1}S{sub 4}+S{sub 2}S{sub 3}) – J{sub 2}(S{sub 1}S{sub 3}+S{sub 2}S{sub 4}) – J{sub 3}S{sub 1}S{sub 2}, where S{sub 1} = S{sub 2} = S{sub 3} = S{sub 4

  20. One-dimensional phosphinite platinum chains based on hydrogen bonding interactions and phosphinite tetranuclear platinum(II)-thallium(I) complexes.

    Science.gov (United States)

    Díez, Alvaro; Forniés, Juan; Gómez, Julio; Lalinde, Elena; Martín, Antonio; Moreno, M Teresa; Sánchez, Sergio

    2007-09-07

    The mononuclear pentafluorophenyl platinum complex containing the chelated diphenylphosphinous acid/diphenylphosphinite system [Pt(C(6)F(5)){(PPh(2)O)(2)H}(PPh(2)OH)] 1 has been prepared and characterised. 1 and the related alkynyl complex [Pt(C[triple bond, length as m-dash]CBu(t)){(PPh(2)O)(2)H}(PPh(2)OH)] 2 form infinite one-dimensional chains in the solid state based on intermolecular O-H[dot dot dot]O hydrogen bonding interactions. Deprotonation reactions of [PtL{(PPh(2)O)(2)H}(PPh(2)OH)] (L = C(6)F(5), C[triple bond, length as m-dash]CBu(t), C[triple bond, length as m-dash]CPh 3) with [Tl(acac)] yields tetranuclear Pt(2)Tl(2) complexes [PtL{(PPh(2)O)(2)H}(PPh(2)O)Tl](2) (L = C(6)F(5) 4, C[triple bond, length as m-dash]CBu(t), C[triple bond, length as m-dash]CPh ). The structure of the tert-butylalkynyl derivative , established by X-ray diffraction, shows two anionic discrete units [Pt(C[triple bond, length as m-dash]CBu(t)){(PPh(2)O)(2)H}(PPh(2)O)](-) joined by two Tl(i) centres via Tl-O and Pt-Tl bonds. Despite the existence of Pt-Tl interactions, they do not show luminescence.

  1. Water oxidation by manganese oxides formed from tetranuclear precursor complexes: the influence of phosphate on structure and activity.

    Science.gov (United States)

    Shevchenko, Denys; Anderlund, Magnus F; Styring, Stenbjörn; Dau, Holger; Zaharieva, Ivelina; Thapper, Anders

    2014-06-28

    Two types of manganese oxides have been prepared by hydrolysis of tetranuclear Mn(iii) complexes in the presence or absence of phosphate ions. The oxides have been characterized structurally using X-ray absorption spectroscopy and functionally by O2 evolution measurements. The structures of the oxides prepared in the absence of phosphate are dominated by di-μ-oxo bridged manganese ions that form layers with limited long-range order, consisting of edge-sharing MnO6 octahedra. The average manganese oxidation state is +3.5. The structure of these oxides is closely related to other manganese oxides reported as water oxidation catalysts. They show high oxygen evolution activity in a light-driven system containing [Ru(bpy)3](2+) and S2O8(2-) at pH 7. In contrast, the oxides formed by hydrolysis in the presence of phosphate ions contain almost no di-μ-oxo bridged manganese ions. Instead the phosphate groups are acting as bridges between the manganese ions. The average oxidation state of manganese ions is +3. This type of oxide has much lower water oxidation activity in the light-driven system. Correlations between different structural motifs and the function as a water oxidation catalyst are discussed and the lower activity in the phosphate containing oxide is linked to the absence of protonable di-μ-oxo bridges.

  2. Copper (II) Complex

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: N – histidyl – 2, 4 – pentanedione Schiff base was prepared from the reaction of histidine and 2, 4 - pentandione. The reaction of methanolic solution of N – histidyl – 2, 4 – pentanedione Schiff base with ethanolic solution of copper (II) chloride gave diaquo bis( N – histidyl - 2, 4 - pentanedionato) copper (II) ...

  3. Copper (II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

    Copper(II) complexes with aroylhydrazones ... The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. ... EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic ...

  4. Copper Phenoxyl Complexes

    OpenAIRE

    Butsch, Katharina

    2010-01-01

    The work described in the following was inspired by radical copper enzymes such as Galactose Oxidase (GO). GO catalyses the two-electron oxidation of terminal alcohols to the corresponding aldehydes using air oxygen. Transfer of two electrons is possible, since GO contains two magnetically coupled one-electron redox centres: a tyrosylate ligand from the apo-protein, which exists either in the tyrosylate or the tyrosyl radical form and is bound to a copper ion possessing two stable oxidation s...

  5. Thiacalix[4]arene-supported kite-like heterometallic tetranuclear Zn(II)Ln(III)3 (Ln = Gd, Tb, Dy, Ho) complexes.

    Science.gov (United States)

    Su, Kongzhao; Jiang, Feilong; Qian, Jinjie; Wu, Mingyan; Xiong, Kecai; Gai, Yanli; Hong, Maochun

    2013-04-01

    Four kite-like tetranuclear Zn(II)Ln(III)3 (Ln= Gd 1, Tb 2, Dy 3, Ho 4) clusters supported by p-tert-butylthiacalix[4]arene (H4BTC4A) have been prepared under solvothermal conditions and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction (PXRD). In the structures of these four complexes, each of them is capped by two tail-to-tail p-tert-butylthiacalix[4]arene molecules to form a bent sandwich-like unit. The photoluminescent analyses reveal that the H4BTC4A is an efficient sensitizer for Tb(3+) ions in 2. The magnetic properties of complexes 1-4 are also investigated, in which complex 3 exhibits slow magnetization relaxation typical for single molecule magnets.

  6. Catecholase activity of a copper(II) complex with a macrocyclic ligand: unraveling catalytic mechanisms.

    Science.gov (United States)

    Koval, Iryna A; Selmeczi, Katalin; Belle, Catherine; Philouze, Christian; Saint-Aman, Eric; Gautier-Luneau, Isabelle; Schuitema, Anna Maria; van Vliet, Marcel; Gamez, Patrick; Roubeau, Olivier; Lüken, Matthias; Krebs, Bernt; Lutz, Martin; Spek, Anthony L; Pierre, Jean-Louis; Reedijk, Jan

    2006-08-07

    We report the structure, properties and a mechanism for the catecholase activity of a tetranuclear carbonato-bridged copper(II) cluster with the macrocyclic ligand [22]pr4pz (9,22-dipropyl-1,4,9,14,17,22,27,28,29, 30-decaazapentacyclo[22.2.1.1(4,7).1(11,14). 1(17,20)]triacontane-5,7(28),11(29),12,18, 20(30),24(27),25-octaene). In this complex, two copper ions within a macrocyclic unit are bridged by a carbonate anion, which further connects two macrocyclic units together. Magnetic susceptibility studies have shown the existence of a ferromagnetic interaction between the two copper ions within one macrocyclic ring, and a weak antiferromagnetic interaction between the two neighboring copper ions of two different macrocyclic units. The tetranuclear complex was found to be the major compound present in solution at high concentration levels, but its dissociation into two dinuclear units occurs upon dilution. The dinuclear complex catalyzes the oxidation of 3,5-di-tert-butylcatechol to the respective quinone in methanol by two different pathways, one proceeding via the formation of semiquinone species with the subsequent production of dihydrogen peroxide as a byproduct, and another proceeding via the two-electron reduction of the dicopper(II) center by the substrate, with two molecules of quinone and one molecule of water generated per one catalytic cycle. The occurrence of the first pathway was, however, found to cease shortly after the beginning of the catalytic reaction. The influence of hydrogen peroxide and di-tert-butyl-o-benzoquinone on the catalytic mechanism has been investigated. The crystal structures of the free ligand and the reduced dicopper(I) complex, as well as the electrochemical properties of both the Cu(II) and the Cu(I) complexes are also reported.

  7. binuclear copper(II) complexes

    Indian Academy of Sciences (India)

    Administrator

    403. Synthesis, electrochemical and magnetic properties of new acylic. 'end-off' binuclear copper(II) complexes. T M RAJENDIRAN, R KANNAPPAN, R VENKATESAN and. P SAMBASIVA RAO. Department of Chemistry, Pondicherry University, R.V. Nagar, Kalapet,. Pondicherry 605 014, India. A series of nonbridged nitrito ...

  8. Water oxidation catalyzed by the tetranuclear Mn complex [Mn(IV)4O5(terpy)4(H2O)2](ClO4)6.

    Science.gov (United States)

    Gao, Yunlong; Crabtree, Robert H; Brudvig, Gary W

    2012-04-02

    The tetranuclear manganese complex [Mn(IV)(4)O(5)(terpy)(4)(H(2)O)(2)](ClO(4))(6) (1; terpy = 2,2':6',2″-terpyridine) gives catalytic water oxidation in aqueous solution, as determined by electrochemistry and GC-MS. Complex 1 also exhibits catalytic water oxidation when adsorbed on kaolin clay, with Ce(IV) as the primary oxidant. The redox intermediates of complex 1 adsorbed on kaolin clay upon addition of Ce(IV) have been characterized by using diffuse reflectance UV/visible and EPR spectroscopy. One of the products in the reaction on kaolin clay is Mn(III), as determined by parallel-mode EPR spectroscopic studies. When 1 is oxidized in aqueous solution with Ce(IV), the reaction intermediates are unstable and decompose to form Mn(II), detected by EPR spectroscopy, and MnO(2). DFT calculations show that the oxygen in the mono-μ-oxo bridge, rather than Mn(IV), is oxidized after an electron is removed from the Mn(IV,IV,IV,IV) tetramer. On the basis of the calculations, the formation of O(2) is proposed to occur by reaction of water with an electrophilic manganese-bound oxyl radical species, (•)O-Mn(2)(IV/IV), produced during the oxidation of the tetramer. This study demonstrates that [Mn(IV)(4)O(5)(terpy)(4)(H(2)O)(2)](ClO(4))(6) may be relevant for understanding the role of the Mn tetramer in photosystem II.

  9. Photocleavage of DNA by copper (II) complexes

    Indian Academy of Sciences (India)

    The chemistry of ternary and binary copper(II) complexes showing efficient visible lightinduced DNA cleavage activity is summarized in this article. The role of the metal in photo-induced DNA cleavage reactions is explored by designing complex molecules having a variety of ligands. Ternary copper(II) complexes with amino ...

  10. Synthesis, crystal structures and antitumor activities of copper(II) complexes with a 2-acetylpyrazine isonicotinoyl hydrazone ligand

    Science.gov (United States)

    Xu, Jun; Zhou, Tao; Xu, Zhou-Qing; Gu, Xin-Nan; Wu, Wei-Na; Chen, Hong; Wang, Yuan; Jia, Lei; Zhu, Tao-Feng; Chen, Ru-Hua

    2017-01-01

    Five complexes, [Cu(L)2]·4.5H2O (1), [Cu(HL)2](NO3)2·CH3OH (2) {[Cu2(L)2(NO3)(H2O)2]·(NO3)}n (3), [Cu2(HL)2(SO4)2]·2CH3OH (4) and [Cu4(L)4Cl4]·5H2O (5) based on HL (where HL = 2-acetylpyrazine isonicotinoyl hydrazone) have been synthesized and characterized by X-ray diffraction analyses. The counter anion and organic base during the synthesis procedure influence the structures of the complexes efficiently, which generate five complexes as mono-, bi-, tetra-nuclear and one-dimensional structures. The antitumor activities of the complexes 1-5 (except for complex 3 with the poor solubility) against the Patu8988 human pancreatic cancer, ECA109 human esophagus cancer and SGC7901 human gastric cancer cell lines are screened by MTT assay. The results indicate that the chelation of Cu(II) with the ligand is responsible for the observed high cytotoxicity of the copper(II) complexes and the 1:2 copper species 1 and 2 demonstrate lower antitumor activities than that of the 1:1 copper species 4 and 5. In addition, the in vitro apoptosis inducing activity of the copper(II) complex 5 against SGC7901 cell line is determined. And the results show that the complex can bring about apoptosis of the cancerous cells in vitro.

  11. A tetranuclear cubane-like nickel(II complex with a tridentate salicylideneimine Schiff base ligand: tetrakis[μ3-4-methyl-N-(2-oxidophenylsalicylideneiminato]tetrakis[methanolnickel(II] methanol 0.8-solvate

    Directory of Open Access Journals (Sweden)

    Gordana Pavlović

    2016-12-01

    Full Text Available The tetranuclear title complex, [Ni4(C14H11NO24(CH3OH4]·0.8CH3OH, has a distorted cubane topology shaped by four Schiff base ligands. The cubane [Ni4(μ3-O4] core is formed via the O atoms from the Schiff base ligands. The octahedrally coordinated NiII ions occupy alternating vertices of the cube. Each NiII ion is coordinated by one O,N,O′-tridentate dianionic ligand, two O atoms of oxidophenyl groups from adjacent ligands and the O atom of a coordinating methanol molecule. The cubane core is stabilized via an intramolecular O—H...O hydrogen bond between the hydroxy group of the coordinating methanol molecules and the phenolate O atom of the aldehyde Schiff base fragment. Additional stabilization is obtained via intramolecular C—H...O hydrogen bonds involving aromatic C—H groups and the oxygen atoms of adjacent methanol molecules. In the crystal, complex molecules are linked into chains parallel to the c axis via weak C—H...O hydrogen bonds. The partial-occupancy disordered methanol solvent molecule has a site occupancy of 0.8 and is linked to the tetranuclear unit via an intermolecular C—H...O hydrogen bond involving a phenolate O atom.

  12. Aspartate aminotransferase is potently inhibited by copper complexes: Exploring copper complex-binding proteome.

    Science.gov (United States)

    Jia, Yuqi; Lu, Liping; Yuan, Caixia; Feng, Sisi; Zhu, Miaoli

    2017-05-01

    Recent researches indicated that a copper complex-binding proteome that potently interacted with copper complexes and then influenced cellular metabolism might exist in organism. In order to explore the copper complex-binding proteome, a copper chelating ion-immobilized affinity chromatography (Cu-IMAC) column and mass spectrometry were used to separate and identify putative Cu-binding proteins in primary rat hepatocytes. A total of 97 putative Cu-binding proteins were isolated and identified. Five higher abundance proteins, aspartate aminotransferase (AST), malate dehydrogenase (MDH), catalase (CAT), calreticulin (CRT) and albumin (Alb) were further purified using a SP-, and (or) Q-Sepharose Fast Flow column. The interaction between the purified proteins and selected 11 copper complexes and CuCl2 was investigated. The enzymes inhibition tests demonstrated that AST was potently inhibited by copper complexes while MDH and CAT were weakly inhibited. Schiff-based copper complexes 6 and 7 potently inhibited AST with the IC50 value of 3.6 and 7.2μM, respectively and exhibited better selectivity over MDH and CAT. Fluorescence titration results showed the two complexes tightly bound to AST with binding constant of 3.89×10(6) and 3.73×10(6)M(-1), respectively and a stoichiometry ratio of 1:1. Copper complex 6 was able to enter into HepG2 cells and further inhibit intracellular AST activity. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. A copper complex (2,2¢-bipyridine)(salicyclideneglycinato) copper(II ...

    Indian Academy of Sciences (India)

    Administrator

    In aqueous–methanol, ascorbic acid reduces the copper(II) complex to form a brown copper(I) species which readily converts to the green precursor copper(II) complex in the presense of dioxygen. The proposed catalytic cycle for this conversion in air is shown below. The copper(II) complex is also catalytically active in.

  14. Synthesis and Structural Characterization of a New Tetranuclear Nickel(II Sulfato Complex Containing the Anionic Form of Di-2-Pyridyl Ketone Oxime

    Directory of Open Access Journals (Sweden)

    Eleni Moushi

    2011-01-01

    Full Text Available The preparation and crystal structure of a tetranuclear Ni(II sulfato cluster containing the anion of di-2-pyridyl ketone oxime, (py2CNO−, are reported. Treatment of NiSO4·6H2O with one equivalent of (py2CNOH and one equivalent of NEt3 in MeOH leads to the compound [Ni4{(py2CNO}4(SO42(MeOH4] (1 in moderate yield. The metal ions are linked together by two 3.2111 and two 2.1110 (Harris notation (py2CNO− ligands, as well as two 2.1100 SO42− ions to create a rare metallacrown-type (12-MC-4 ring. Strong H-bond intermolecular interactions in 1 lead to the formation of a 1D chain along the axis. Characteristic IR bands are discussed in terms of the known structure of 1.

  15. Syntheses of copper complexes of nicotinohydroxamic and ...

    African Journals Online (AJOL)

    Syntheses of copper complexes of nicotinohydroxamic and isonicotinohydroxamic acids. A.O Aliyu, A.P Egwaikhide, C.E Gimba. Abstract. Nicotinohydroxamic acid (NHA) and isonicotinohydroxamic acid (INHA) were synthesized, characterized by electronic and spectral studies,magnetic measurements and their pKa ...

  16. ANTIMICROBIAL ACTIVITY OF COPPER(II COMPLEXES

    Directory of Open Access Journals (Sweden)

    Andrea Čongrádyová

    2014-02-01

    Full Text Available Two novel copper(II 5-chlorosalicylate complexes with either 1,10-phenantroline or its methyl derivative 2,9-dimethyl-1,10-phenanthroline (neocuproine have been prepared and studied. A potential antimicrobial or antifungal activity of both complexes has been tested on prokaryotic Escherichia coli and eukaryotic Saccharomyces cerevisiae model organisms. Crystal structure of [Cu(phen(5-Clsal(5-ClsalH2]2 a dimeric structure, whereas the second complex of formula [Cu(H2O(5-Clsal(Neo] has been shown to be monomeric. Our results confirmed the toxic effect of prepared copper complexes as well as bioactive ligands on the yeast and bacteria growth. The effect of copper complexes was stronger compared to the solutions of free ligands. Our preliminary results showed that the complex [Cu(H2O(5-Clsal(Neo] exhibited higher antimicrobial activity compared to the complex [Cu(phen(5-Clsal(5-ClsalH2]2.

  17. Competing Magnetic Exchange Interactions in Tetranuclear d(1) Systems: Synthesis, Structure, and Magnetochemistry of a Neutral Vanadium(IV) Complex with a {(VO)(4)(&mgr;(3)-OR)(2)(&mgr;(2)-OR)(4)}(2+) Core.

    Science.gov (United States)

    Plass, Winfried

    1997-05-07

    The complex [{VO(L)}(2){VO(acac)}(2)(&mgr;(2)-OMe)(2)] 1 can be synthesized by reaction of the Schiff base ligand N,N-bis(2-hydroxyethyl)-N'-(2-pyrrolylmethylidene)ethylenediamine (H(2)L) with [VO(acac)(2)] (Hacac = 2,4-pentanedione). The compound 1.MeOH has been characterized by IR, UV/vis, and ESR spectroscopy as well as magnetic susceptibility measurements. A single-crystal diffraction study performed on 1. MeOH gives the following crystal data: triclinic, P&onemacr;, a = 7.352(2) Å, b = 12.584(4) Å, c = 12.826(4) Å, alpha = 107.61(2) degrees, beta = 102.96(2) degrees, gamma = 95.25(2) degrees, Z = 1. The tetranuclear {(VO)(4)(&mgr;(3)-OR)(2)(&mgr;(2)-OR)(4)}(2+) core of 1 is composed of three different types of edge-shared binuclear units, an anti-coplanar, two syn-coplanar, and two twist configurations. Consistent with this connectivity pattern, analysis of the magnetic data reveals competing ferromagnetic and antiferromagnetic exchange interactions within the tetranuclear core structure. Both ESR and magnetic data indicate a singlet ground state for 1. In addition, the general magnetic behavior of oxovanadium(IV) clusters is discussed on the basis of classification schemes derived from simple binuclear fragmentation patterns. Consistent with the superexchange mechanism expected to be operative for binuclear oxovanadium(IV) units with syn-coplanar configuration, the corresponding magnetic exchange parameter J(sc) of 1 (V.V = 3.410(2) Å) is determined to be antiferromagnetic at -153 cm(-)(1).

  18. Copper complexes as chemical nucleases

    Indian Academy of Sciences (India)

    Unknown

    intercalation more favourable between the π-system of the ligand and the DNA base pairs. The dpq and dppz complexes, however, drastically differ in their cleavage activities in presence of a reducing agent like ascorbic acid. The anomalous activity of 5 could be related to the enhancement of the stability of the cuprous ...

  19. Catalytic aspects of a copper (II) complex: biological oxidase to ...

    Indian Academy of Sciences (India)

    This copper complex displays excellent catalytic efficiency, kcat /KM (h⁻¹) = 6.17 × 10⁵ towards the oxidative coupling of 2-aminophenol (2-AP) to aminophenoxazin-3-one. Further, upon stoichiometric addition of copper(II) complex to 3,5-DTBC in presence of molecular oxygen in ethanol medium, the copper complex ...

  20. Biogenic nanoparticles: copper, copper oxides, copper sulphides, complex copper nanostructures and their applications.

    Science.gov (United States)

    Rubilar, Olga; Rai, Mahendra; Tortella, Gonzalo; Diez, Maria Cristina; Seabra, Amedea B; Durán, Nelson

    2013-09-01

    Copper nanoparticles have been the focus of intensive study due to their potential applications in diverse fields including biomedicine, electronics, and optics. Copper-based nanostructured materials have been used in conductive films, lubrification, nanofluids, catalysis, and also as potent antimicrobial agent. The biogenic synthesis of metallic nanostructured nanoparticles is considered to be a green and eco-friendly technology since neither harmful chemicals nor high temperatures are involved in the process. The present review discusses the synthesis of copper nanostructured nanoparticles by bacteria, fungi, and plant extracts, showing that biogenic synthesis is an economically feasible, simple and non-polluting process. Applications for biogenic copper nanoparticles are also discussed.

  1. Effects of Copper Exchange Levels on Complexation of Ammonia in ...

    African Journals Online (AJOL)

    NJD

    Cation exchange, catalysis, copper, complexation, copper ammines. 1. Introduction. Copper-exchanged zeolites ... characterization of cation-exchanged zeolites is ammonia.7. Ammonia is small enough (ca. 3.70 × 3.99 .... quartz glass sample cuvettes and the diffuse reflectance spec- troscopy measurements obtained from ...

  2. Effects of Copper Exchange Levels on Complexation of Ammonia in ...

    African Journals Online (AJOL)

    The copper ammine complexes of the various copper levels per unit cell were characterized and analyzed by a combination of diffuse reflectance, X-ray powder diffraction, FT-infrared spectroscopy, electron paramagnetic resonance and nuclear magnetic resonance spectroscopic methods. At low copper exchange levels ...

  3. Structural and magnetic properties of Mn(III) and Cu(II) tetranuclear azido polyoxometalate complexes: multifrequency high-field EPR spectroscopy of Cu4 clusters with S = 1 and S = 2 ground states.

    Science.gov (United States)

    Mialane, Pierre; Duboc, Carole; Marrot, Jérôme; Rivière, Eric; Dolbecq, Anne; Sécheresse, Francis

    2006-02-20

    Two new azido-bridged polyoxometalate compounds were synthesized in acetonitrile/methanol media and their molecular structures have been determined by X-ray crystallography. The [[(gamma-SiW10O36)Mn2(OH)2(N3)(0.5)(H2O)(0.5)]2(mu-1,3-N3)](10-) (1 a) tetranuclear Mn(III) complex, in which an end-to-end N3- ligand acts as a linker between two [(gamma-SiW10O36)Mn2(OH)2]4- units, represents the first manganese-azido polyoxometalate. The magnetic properties have been studied considering the spin Hamiltonian H = -J1(S1S2+S1*S2*)-J2(S1S1*), showing that antiferromagnetic interactions between the paramagnetic centers (g = 1.98) occur both through the di-(mu-OH) bridge (J1 = -25.5 cm(-1)) and the mu-1,3-azido bridge (J2 = -19.6 cm(-1)). The [(gamma-SiW10O36)2Cu4(mu-1,1,1-N3)2(mu-1,1-N3)2]12- (2 a) tetranuclear Cu(II) complex consists of two [gamma-SiW10O36Cu2(N3)2]6- subunits connected through the two mu-1,1,1-azido ligands, the four paramagnetic centers forming a lozenge. The magnetic susceptibility data have been fitted. This reveals ferromagnetic interactions between the four Cu(II) centers, leading to an S=2 ground state (H = -J1(S1S2+S1*S2*)-J2(S2S2*), J1 = +294.5 cm(-1), J2 = +1.6 cm(-1), g = 2.085). The ferromagnetic coupling between the Cu(II) centers in each subunit is the strongest ever observed either in a polyoxometalate compound or in a diazido-bridged Cu(II) complex. Considering complex 2 a and the previously reported basal-basal di-(mu-1,1-N3)-bridged Cu(II) complexes in which the metallic centers are not connected by other magnetically coupling ligands, the linear correlation J1 = 2639.5-24.95*theta(av) between the theta(av) bridging angle and the J1 coupling parameter has been proposed. The electronic structure of complex 2 a has also been investigated by using multifrequency high-field electron paramagnetic resonance (HF-EPR) spectroscopy between 95 and 285 GHz. The spin Hamiltonian parameters of the S = 2 ground state (D = -0.135(2) cm(-1), E = -0

  4. Intercalation processes of copper complexes in DNA

    Science.gov (United States)

    Galindo-Murillo, Rodrigo; García-Ramos, Juan Carlos; Ruiz-Azuara, Lena; Cheatham, Thomas E.; Cortés-Guzmán, Fernando

    2015-01-01

    The family of anticancer complexes that include the transition metal copper known as Casiopeínas® shows promising results. Two of these complexes are currently in clinical trials. The interaction of these compounds with DNA has been observed experimentally and several hypotheses regarding the mechanism of action have been developed, and these include the generation of reactive oxygen species, phosphate hydrolysis and/or base-pair intercalation. To advance in the understanding on how these ligands interact with DNA, we present a molecular dynamics study of 21 Casiopeínas with a DNA dodecamer using 10 μs of simulation time for each compound. All the complexes were manually inserted into the minor groove as the starting point of the simulations. The binding energy of each complex and the observed representative type of interaction between the ligand and the DNA is reported. With this extended sampling time, we found that four of the compounds spontaneously flipped open a base pair and moved inside the resulting cavity and four compounds formed stacking interactions with the terminal base pairs. The complexes that formed the intercalation pocket led to more stable interactions. PMID:25958394

  5. Copper(II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

    Unknown

    The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. ... the metal ions 3. In the following account, the results obtained in our study on copper(II) chemistry with these ..... Rev.77165;. (b) Fenton D E 1983 Advances in inorganic and bio-organic mechanisms (ed.) A G Sykes.

  6. Mixed-ligand binuclear copper (II) complex of 5 ...

    Indian Academy of Sciences (India)

    Absorption spectroscopy exhibits d-d transition at 628 nm, which further supports the square pyramidal geometry around the copper(II) ions. EPR spectrum of the copper(II) complex at room temperature shows a broad signal without any splitting pattern at ∥ = 2.26, ⊥ = 2.03 and the magnetic moment (eff = 1.31 BM) ...

  7. Vectorization of copper complexes via biocompatible and biodegradable PLGA nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Courant, T; Roullin, V G; Andry, M C [Institut de Chimie Moleculaire de Reims, CNRS UMR 6229, UFR Pharmacie Reims, 51 rue Cognacq-Jay, F-51100 Reims (France); Cadiou, C; Chuburu, F [Institut de Chimie Moleculaire de Reims, CNRS UMR 6229, UFR des Sciences Exactes et Naturelles, Batiment 18-Europol' Agro, BP 1039, F-51687 Reims Cedex 2 (France); Delavoie, F [Laboratoire de Microscopie Electronique Analytique, INSERM UMRS 926, 21 rue Clement Ader, F-51685 Reims Cedex 2 (France); Molinari, M [Laboratoire de Microscopies et d' Etudes des Nanostructures, UFR des Sciences, Universite de Reims Champagne-Ardenne, 21 rue Clement Ader, F-51685 Reims Cedex 2 (France); Gafa, V, E-mail: gaelle.roullin@univ-reims.fr, E-mail: francoise.chuburu@univ-reims.fr [EA4303 ' Inflammation et Immunite de l' Epithelium Respiratoire' , IFR53, UFR de Pharmacie, Universite de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, F-51100 Reims (France)

    2010-04-23

    A double emulsion-solvent diffusion approach with fully biocompatible materials was used to encapsulate copper complexes within biodegradable nanoparticles, for which the release kinetics profiles have highlighted their potential use for a prolonged circulating administration.

  8. Synthesis and Characterization of Copper (II) Complex of Glycine ...

    African Journals Online (AJOL)

    Copper(II)Complex of amino acid was synthesized by refluxing the mixtures of ethanolic solutions of glycine and copper(II)chloride. The complex compound was characterized by melting point (225oC), PH 5.78 at 28oC, moisture content of 5% with a yield of 68%. The compound is insoluble in water but readily soluble in ...

  9. Tetranuclear hetero-metal [Co(II)2Ln(III)2] (Ln = Gd, Tb, Dy, Ho, La) complexes involving carboxylato bridges in a rare μ4-η(2):η(2) mode: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Abtab, Sk Md Towsif; Majee, Mithun Chandra; Maity, Manoranjan; Titiš, Ján; Boča, Roman; Chaudhury, Muktimoy

    2014-02-03

    A new family of 3d-4f heterometal 2 × 2 complexes [Co(II)2(L)2(PhCOO)2Ln(III)2(hfac)4] (1-5) (Ln = Gd (compound 1), Tb (compound 2), Dy (compound 3), Ho (compound 4), and La (compound 5)) have been synthesized in moderate yields (48-63%) following a single-pot protocol using stoichiometric amounts (1:1 mol ratio) of [Co(II)(H2L)(PhCOO)2] (H2L = N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine) as a metalloligand and [Ln(III)(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) as a lanthanide precursor compound. Also reported with this series is the Zn-Dy analog [Zn(II)2(L)2(PhCOO)2Dy(III)2(hfac)4] 6 to help us in understanding the magnetic properties of these compounds. The compounds 1-6 are isostructural. Both hexafluoroacetylacetonate and benzoate play crucial roles in these structures as coligands in generating a tetranuclear core of high thermodynamic stability through a self-assembly process. The metal centers are arranged alternately at the four corners of this rhombic core, and the carboxylato oxygen atoms of each benzoate moiety bind all of the four metal centers of this core in a rare μ4-η(2):η(2) bridging mode as confirmed by X-ray crystallography. The magnetic susceptibility and magnetization data confirm a paramagnetic behavior, and no remnant magnetization exists in any of these compounds at vanishing magnetic field. The metal centers are coupled in an antiferromagnetic manner in these compounds. The [Co(II)2Dy(III)2] compound exhibits a slow magnetic relaxation below 6 K, as proven by the AC susceptibility measurements; the activation energy reads U/kB = 8.8 K (τ0 = 2.0 × 10(-7) s) at BDC = 0, and U/kB = 7.8 K (τ0 = 3.9 × 10(-7) s) at BDC = 0.1 T. The [Zn(II)2Dy(III)2] compound also behaves as a single-molecule magnet with U/kB = 47.9 K and τ0 = 2.75 × 10(-7) s.

  10. [Bactericidal properties of copper (II) complexes with 1-alkylimidazole].

    Science.gov (United States)

    Radzymińska-Lenarcik, E; Mirska, I; Pernak, J

    1998-01-01

    The copper(II) complexes with 1-alkylimidazole were prepared. Bactericidal properties of the obtained complexes against Staphylococcus aureus, Micrococcus luteus and Pseudomonas aeruginosa were studied. Particularly high activity against microbial strains was shown by complex [Cu(1-C4H9Im)4(CIO4)2].

  11. Photocleavage of DNA by copper(II) complexes

    OpenAIRE

    Chakravarty, Akhil R

    2006-01-01

    The chemistry of ternary and binary copper(II) complexes showing efficient visible lightinduced DNA cleavage activity is summarized in this article. The role of the metal in photo-induced DNA cleavage reactions is explored by designing complex molecules having a variety of ligands. Ternary copper(II) complexes with amino acid like L-methionone or L-lysine and phenanthroline base are efficient photocleavers of DNA. Complexes of formulation $[Cu(L^n)(phen)](ClO_4)$ with NSO-donor Schiff base $(...

  12. Syntheses, structures and magnetic properties of tetranuclear cubane-type and heptanuclear wheel-type nickel(ii) complexes with 3-methoxysalicylic acid derivatives.

    Science.gov (United States)

    Kobayashi, Fumiya; Ohtani, Ryo; Teraoka, Saki; Kosaka, Wataru; Miyasaka, Hitoshi; Zhang, Yingjie; Lindoy, Leonard F; Hayami, Shinya; Nakamura, Masaaki

    2017-07-04

    Two ferromagnetic multinuclear Ni(ii) clusters, [Ni4L(1)4(μ3-OMe)4(CH3OH)4] (1) and [Ni7(HL(2))6(μ3-OMe)6]Cl2 (2), and a mononuclear complex [NiL(3)]·2H2O (3) (HL(1) = benzyl 2-hydroxy-3-methoxybenzoate; H2L(2) = 1-(2-hydroxy-3-methoxybenzamido)-2-(benzylideneamino)ethane; H2L(3) = 1-(2-hydroxy-3-methoxybenzamido)-2-(pyridylmethyleneamino)ethane) were synthesised, and their structures and magnetic behaviours were investigated in detail. 1 has a [Ni4O4] cubane structure while 2 has a wheel-like [Ni@Ni6] arrangement. The temperature-dependent magnetic susceptibilities for 1 and 2 are in accord with the presence of dominating intra-cluster ferromagnetic interactions between Ni(ii) ions. The best fits for their behaviours gave the following parameters: J1 = 11.06 cm(-1), J2 = 1.43 cm(-1), g = 2.29 for 1, and J1 = 6.87 cm(-1), J2 = -3.41 cm(-1), g = 2.24 for 2.

  13. Synergetic Effect of Blended Alkylamines for Copper Complex Ink To Form Conductive Copper Films.

    Science.gov (United States)

    Xu, Wen; Wang, Tao

    2017-01-10

    Cu(II) complex ink consisting of copper formate (Cuf) and a primary alkylamine could yield highly conductive copper films at low heating temperatures without a reducing atmosphere. A synergetic effect of the blended alkylamines on the formation of conductive films was observed. It was found that blending two types of amines with different alkyl chain lengths as ligands could improve the conductivity of copper films, compared with using one of these amines alone. The decomposition mechanism of the Cuf-amine complex and the role of amines with different alkyl chain lengths were investigated. It was found that the decrease in the decomposition temperature and the formation of copper films were attributed to the activating effect and capping effect of the amine, and these two effects were dependent on the alkyl chain length. The relative intensity of the dual effects determined the decomposition rate of the complex and the nucleation and growth of particles. The use of blended amines with different alkyl chain lengths as ligands could balance the two effects and lead to appropriate nucleation and growth rates, so that densely packed copper films with low resistivity could be obtained at low heating temperature in a short time. The Cuf-butylamine-octylamine (Cuf-butyl-octyl) ink with 1:1 molar ratio of the amines showed the best performance. The understanding of the synergetic effect could provide guidance to the design of copper complex inks to control the morphology of the films.

  14. [Biohydrometallurgical technology of a complex copper concentrate process].

    Science.gov (United States)

    Murav'ev, M I; Fomchenko, N V; Kondrat'eva, T F

    2011-01-01

    Leaching of sulfide-oxidized copper concentrate of the Udokan deposit ore with a copper content of 37.4% was studied. In the course of treatment in a sulfuric acid solution with pH 1.2, a copper leaching rate was 6.9 g/kg h for 22 h, which allowed extraction of 40.6% of copper. As a result of subsequent chemical leaching at 80 degrees C during 7 h with a solution of sulphate ferric iron obtained after bio-oxidation by an association of microorganisms, the rate of copper recovery was 52.7 g/kg h. The total copper recovery was 94.5% (over 29 h). Regeneration of the Fe3+ ions was carried out by an association of moderately thermophilic microorganisms, including bacteria of genus Sulfobacillus and archaea of genus Ferroplasma acidiphilum, at 1.0 g/l h at 40 degrees C in the presence of 3% solids obtained by chemical leaching of copper concentrate. A technological scheme of a complex copper concentrate process with the use of bacterial-chemical leaching is proposed.

  15. In vitro complexes of copper and zinc with chlorophyll

    Directory of Open Access Journals (Sweden)

    JELENA PETROVIC

    2006-05-01

    Full Text Available Complexes of copper and zinc with chlorophyll, the major photosynthesis pigment, were studied by Vis, FTIR and fluorescence spectroscopy. Two types of complexes were recognized. While copper replaces the central magnesium atom of chlorophyll to form a “central” Cu–Chl complex, this was not proposed in the case of zinc. Instead, the zinc-mediated formation of a 6-membered chelate cycle fused at the periphery of the chlorophyll structure is proposed. The latter event could be ascribed to allomerization reactions of chlorophyll.

  16. Photocleavage of DNA by copper(II) complexes

    Indian Academy of Sciences (India)

    pathway) as the reactive species. Keywords. Copper(II) complexes; DNA photocleavage; red light laser; phenanthroline bases. 1. Introduction. Transition metal complexes that are suitable for binding and cleaving double-stranded DNA are of con- siderable current interest due to their various appli- cations in nucleic acid ...

  17. Three-dimensional tetranuclear Cd(II) coordination network based on a 1,3-alternate calix[4]arene derivative

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ji; Ju, Hui Yeong; Park, Ki Min [Dept. of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju (Korea, Republic of); Moon, ASuk Hee [Dept. of Food and Nutrition, Kyungnam College of Inform ation and Technology, Busan (Korea, Republic of); Kang, Young Jin [Div. of cience Education, Kangwon National University, Chuncheon (Korea, Republic of)

    2015-08-15

    Polynuclear coordination polymers can exhibit more intriguing network topologies and better functionalities than those of common complexes because they have metal-cluster nodes for the construction of multidimensional frameworks and the potential applications induced by collaborative activities between metal ions. New tetranuclear Cd(II) coordination polymer 1 based on 1,3-alternate calix arene derivative (H{sub 4} CTA) with four carboxyl pendant arms has been synthesized by the solvo thermal reaction at 110 .deg. C for 2 days. Compound 1 shows a 3-D framework consisting of tetranuclear Cd(II) cluster core as a metal-cluster node and 1,3-alternate H{sub 4}CTA as a multidentate linker. The coordination polymer 1 displays intense blue emission, implying that this tetranuclear Cd(II) coordination polymer could be a suitable material in the area of luminescence research.

  18. metal complexes of copper(ii)

    African Journals Online (AJOL)

    Zinc(II) complex is diamagnetic. The cobalt(II) complex was found with paramagnetic character (4.11 B.M.). Also, in the FT-IR spectra of oligomer-metal complexes, there was no evidence associated with coordinated water molecules. Because this band generally was observed at 3700-3500 cm-1 region as a broad band.

  19. Copper Recovery from Yulong Complex Copper Oxide Ore by Flotation and Magnetic Separation

    Science.gov (United States)

    Han, Junwei; Xiao, Jun; Qin, Wenqing; Chen, Daixiong; Liu, Wei

    2017-09-01

    A combined process of flotation and high-gradient magnetic separation was proposed to utilize Yulong complex copper oxide ore. The effects of particle size, activators, Na2S dosage, LA (a mixture of ammonium sulfate and ethylenediamine) dosage, activating time, collectors, COC (a combination collector of modified hydroxyl oxime acid and xanthate) dosage, and magnetic intensity on the copper recovery were investigated. The results showed that 74.08% Cu was recovered by flotation, while the average grade of the copper concentrates was 21.68%. Another 17.34% Cu was further recovered from the flotation tailing by magnetic separation at 0.8 T. The cumulative recovery of copper reached 91.42%. The modifier LA played a positive role in facilitating the sulfidation of copper oxide with Na2S, and the combined collector COC was better than other collectors for the copper flotation. This technology has been successfully applied to industrial production, and the results are consistent with the laboratory data.

  20. 21 CFR 73.3110 - Chlorophyllin-copper complex, oil soluble.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chlorophyllin-copper complex, oil soluble. 73.3110...-copper complex, oil soluble. (a) Identity. The color additve is chlorophyllin-copper complex, oil soluble... complex, oil soluble (5 percent in palm oil, peanut oil, and hydrogenated peanut oil), shall conform to...

  1. Unprecedented hetero-geometric discrete copper(II) complexes ...

    Indian Academy of Sciences (India)

    hydrogen peroxide. The generation of Cu(I) species in the catalytic pathway established by electrochemi- cal analysis was further confirmed by electron para- magnetic resonance (EPR) spectroscopy. EPR titration suggests that the generation of radical of catechol in presence of copper complex is playing a key role towards ...

  2. COPPER(II) COMPLEXES OF o -VANILLIN ACETYLHYDRAZONE ...

    African Journals Online (AJOL)

    COPPER(II) COMPLEXES OF o-VANILLIN ACETYLHYDRAZONE (H2L) AND THE SINGLE-CRYSTAL X-RAY STRUCTURE OF [{Cu(HL)(HO)(HPZ)}].NO3. Ousmane Diouf*, Mohamed Gaye, Diariétou Gningue Sall, Abdou Salam Sall, Yves Pontillon, Andrea Caneschi ...

  3. Photocytotoxic ternary copper(II) complexes of histamine Schiff base ...

    Indian Academy of Sciences (India)

    show efficient DNA photocleavage and photocytotoxic activity in various cancer cells in visible or near-IR red light.25–30 In addition, dichloro-oxovanadium(IV) complexes are shown to form photo-induced ds-DNA crosslinks resulting apoptotic cell death.31. The present work stems from our interest to design new copper(II) ...

  4. Copper(II) complex of 3-cinnamalideneacetylacetone: Synthesis and ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. A bidentate ligand derived from cinnamaldehyde and acetylacetone and its copper(II) complex have been synthesized and characterized by elemental analysis,. UV-Vis, IR, ESR and magnetic susceptibility measurements. Magnetic susceptibility measurements, ESR and electronic spectral data indicate the ...

  5. Unprecedented hetero-geometric discrete copper (II) complexes ...

    Indian Academy of Sciences (India)

    Unprecedented hetero-geometric discrete copper(II) complexes: Crystal structure and bio-mimicking of Catecholase activity. ABHRANIL DE DHANANJAY DEY HARE RAM YADAV MILAN MAJI VINAYAK RANE R M KADAM ANGSHUMAN ROY CHOUDHURY BHASKAR BISWAS. Regular Article Volume 128 Issue 11 ...

  6. Copper complexes as biomimetic models of catechol oxidase : mechanistic studies

    NARCIS (Netherlands)

    Koval, Iryna A.

    2006-01-01

    The research described in this thesis deals with the synthesis of copper(II) complexes with phenol-based or macrocyclic ligands, which can be regarded as model compounds of the active site of catechol oxidase, and with the mechanism of the catalytic oxidation of catechol mediated by these compounds.

  7. Complex with fullerenol and copper (II

    Directory of Open Access Journals (Sweden)

    Đorđević Aleksandar N.

    2009-01-01

    Full Text Available Polyhydroxy fulleren derivates have significant potential in nanomedical application. Research of polyanion nanoparticle fullerenol C60(OH24 is of high significance for interpretation of biological mechanisms. This paper investigated the properties of polyanion nanoparticle fullerenol C60(OH24 as a potential polydentat ligand. Fullerenol C60(OH24 water solutions were added in solution of [Cu(NH34]2+ in order to form a dark brown complex. Absorbance of [Cu(NH34]2+ solution was decreasing with increasing concentration of polyanion nanoparticle nanoligand fullerenol. This relation was determined in all investigated concentrations of [Cu(NH34]2+. The ratio of Cu2+ complex composer to polyanion polydentat nanoligand fullerenol had an increase from 1.5 to 9, proportional to the increase of the complex composer concentration and decrease of polyanion polydentat nanoligand fullerenol in the alkali medium. The thermogram TGA-DTA of fullerenol and fullerenol and CuSO4 complex, clearly show endothermic effects (which are the result of dehydratation and dehydroxylation and exothermic effects (as the result of degradation of C60(OH24 molecules and processes of oxidation in CO, CO2. At the beginning of TGA-DTA fullerenol thermogram, there is a very well defined endothermic peak of water loss at 100°C, followed by mass decrease as a consequence of lost hydroxyl groups, covalent bounded for C60. The influence of the complex composer is manifested in the moving of thermal stability towards lower temperatures. The complex composer is a catalyst of the process of polyanion polydentat nanoligand fullerenol oxidation to CO and CO2. The temperature peak of fullerenol oxidation is at 490°C and in the case of complex oxidation two peaks were detected at 380 and 410°C.

  8. Complexes of Lapacholate with Cobalt and Copper

    Directory of Open Access Journals (Sweden)

    R. A. Farfán

    2012-01-01

    Full Text Available The molecular structures of two isostructural complexes of lapacholate (Lap anion and dimethylformamide (DMF, M(Lap2(DMF2 with M: Co Cu, were determined by X-ray diffraction methods. The substances crystallize in the triclinic space group P1¯ with one molecule per unit cell and cell constants a=7.7591(3, b=10.3560(3, c=11.2224(4 Å, α=95.110(2, β=94.310(2, and γ=107.704(2° for the Co complex and a=7.9308(2, b=10.0033(4, c=10.7508(4, α=97.387(2, β=93.621(2, and γ=103.980(2° for the Cu complex. The structures were solved from 2933 (Co and 2888 (Cu reflections with I>2σ (I and refined by full matrix least squares to agreement R1-factors of 0.041 (Co and 0.033 (Cu. The metal M(II ion is sited on a crystallographic inversion center in a MO6 distorted octahedral environment. This ion is coordinated equatorially to two lapacholate anions through their adjacent carbonyl and phenol oxygen atoms [M–O bond distances of 2.134(1 and 2.008(1 Å (Co and 2.301(1 and 1.914(1 Å (Cu] and axially to two DMF molecules through oxygen atoms [M–O bond lengths of 2.143(1 Å (Co and 2.069(1 Å (Cu]. The solid state IR transmittance and solution electronic absorption spectra of both Co and Cu compounds are also reported and compared to each other and to the corresponding spectra of other members of the lapacholate metal family of complexes.

  9. Synthesis and characterization of a chiral dimeric copper(II) complex ...

    Indian Academy of Sciences (India)

    Unknown

    IR, UV–visible and EPR spectroscopy and circular dichroism (CD) studies. Keywords. Dinuclear copper(II) complex; crystal structure; chiral properties. 1. Introduction. Binuclear complexes of copper have received much attention because of their relevance to the type 3 copper found in multicopper-containing proteins such.

  10. Structure, bonding, and catecholase mechanism of copper bispidine complexes.

    Science.gov (United States)

    Comba, Peter; Martin, Bodo; Muruganantham, Amsaveni; Straub, Johannes

    2012-09-03

    Oxygen activation by copper(I) complexes with tetra- or pentadentate mono- or dinucleating bispidine ligands is known to lead to unusually stable end-on-[{(bispidine)Cu}(2)(O(2))](2+) complexes (bispidines are methyl-2,4-bis(2-pyridin-yl)-3,7-diazabicyclo-[3.3.1]-nonane-9-diol-1,5-dicarboxylates); catecholase activity of these dinuclear Cu(II/I) systems has been demonstrated experimentally, and the mechanism has been thoroughly analyzed. The present density functional theory (DFT) based study provides an analysis of the electronic structure and catalytic activity of [{(bispidine)Cu}(2)(O(2))](2+). As a result of the unique square pyramidal coordination geometry, the d(x(2)-y(2)) ground state leads to an unusual σ/π bonding pattern, responsible for the stability of the peroxo complex and the observed catecholase activity with a unique mechanistic pathway. The oxidation of catechol to ortho-quinone (one molecule per catalytic cycle and concomitant formation of one equivalent of H(2)O(2)) is shown to occur via an associative, stepwise pathway. The unusual stability of the end-on-peroxo-dicopper(II) complex and isomerization to copper(II) complexes with chelating catecholate ligands, which inhibit the catalytic cycle, are shown to be responsible for an only moderate catalytic activity.

  11. Study on the mechanism of copper-ammonia complex decomposition in struvite formation process and enhanced ammonia and copper removal.

    Science.gov (United States)

    Peng, Cong; Chai, Liyuan; Tang, Chongjian; Min, Xiaobo; Song, Yuxia; Duan, Chengshan; Yu, Cheng

    2017-01-01

    Heavy metals and ammonia are difficult to remove from wastewater, as they easily combine into refractory complexes. The struvite formation method (SFM) was applied for the complex decomposition and simultaneous removal of heavy metal and ammonia. The results indicated that ammonia deprivation by SFM was the key factor leading to the decomposition of the copper-ammonia complex ion. Ammonia was separated from solution as crystalline struvite, and the copper mainly co-precipitated as copper hydroxide together with struvite. Hydrogen bonding and electrostatic attraction were considered to be the main surface interactions between struvite and copper hydroxide. Hydrogen bonding was concluded to be the key factor leading to the co-precipitation. In addition, incorporation of copper ions into the struvite crystal also occurred during the treatment process. Copyright © 2016. Published by Elsevier B.V.

  12. Self-assembled carboxylate complexes of zinc, nickel and copper

    Science.gov (United States)

    Deka, Kaustavmoni; Barooah, Nilotpal; Sarma, Rupam Jyoti; Baruah, Jubaraj B.

    2007-02-01

    A metallo-organic hybrid acid namely tetra-aquo bis-4-carboxy- N-phthaloylglycinato zinc(II) dihydrate is prepared and characterised. In this complex the hydrogen bonding by free carboxylic acid group and π-π interactions between the rings in crystal lattice contributes to the formation of self-assembled structure. A monomeric nickel complex from 2-carbomethoxy benzoic acid ( L2H) and pyridine [Ni( L2)(py) 3(H 2O) 2] L2 is prepared (where py = pyridine). This complex has ionic as well as monodentate carboxylates. It forms self-assembly by C-H⋯π as well as hydrogen-bonding interactions. The 2-carbomethoxy benzoic acid ( L2H) forms dimeric copper complex [Cu 2( L2) 4(H 2O) 2]2H 2O which has an extended chain structure through hydrogen-bond interactions.

  13. Synthesis and characterization of copper(II) complexes of semicarbazones

    Science.gov (United States)

    Chandra, Usha; Chandra, Sulekh

    1992-08-01

    Copper(II) complexes of the general composition Cu(ligand) 2X 2 (where X=CI -, Br -, NO -3, ClO -4 and 1/2 SO 2-4) and Cu(ligand) (CH 3COO) 2 have been synthesized with methyl n-pentyl ketone and methyl n-hexyl ketone semicarbazones. All the complexes prepared have been characterized by elemental analysis, magnetic moment, molar conductance, IR, electronic and electron spin resonance spectral studies. The complexes Cu(ligand) 2X 2 (X = Cl -, Br -, NO -3) and Cu(ligand) (CH 3COO) 2 may have tetragonal geometry, while the complexes Cu(ligand) 2X 2 (X = ClO -4 and 1/2 SO 2-4) may be assigned a five-coordinated trigonally distorted square pyramidal geometry.

  14. Neuroprotective copper bis(thiosemicarbazonato complexes promote neurite elongation.

    Directory of Open Access Journals (Sweden)

    Laura Bica

    Full Text Available Abnormal biometal homeostasis is a central feature of many neurodegenerative disorders including Alzheimer's disease (AD, Parkinson's disease (PD, and motor neuron disease. Recent studies have shown that metal complexing compounds behaving as ionophores such as clioquinol and PBT2 have robust therapeutic activity in animal models of neurodegenerative disease; however, the mechanism of neuroprotective action remains unclear. These neuroprotective or neurogenerative processes may be related to the delivery or redistribution of biometals, such as copper and zinc, by metal ionophores. To investigate this further, we examined the effect of the bis(thiosemicarbazonato-copper complex, Cu(II(gtsm on neuritogenesis and neurite elongation (neurogenerative outcomes in PC12 neuronal-related cultures. We found that Cu(II(gtsm induced robust neurite elongation in PC12 cells when delivered at concentrations of 25 or 50 nM overnight. Analogous effects were observed with an alternative copper bis(thiosemicarbazonato complex, Cu(II(atsm, but at a higher concentration. Induction of neurite elongation by Cu(II(gtsm was restricted to neurites within the length range of 75-99 µm with a 2.3-fold increase in numbers of neurites in this length range with 50 nM Cu(II(gtsm treatment. The mechanism of neurogenerative action was investigated and revealed that Cu(II(gtsm inhibited cellular phosphatase activity. Treatment of cultures with 5 nM FK506 (calcineurin phosphatase inhibitor resulted in analogous elongation of neurites compared to 50 nM Cu(II(gtsm, suggesting a potential link between Cu(II(gtsm-mediated phosphatase inhibition and neurogenerative outcomes.

  15. Superoxide dismutase mimetic activity of cytokinin-copper(II) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, H.; Hirobe, M.

    1986-05-29

    Dissociation constants of cytokinins, derivatives of purine which form complexes which cupric ion, were determined by spectrophotometry and the stability constants of their copper complexes by pH titration. The values found for kinetic were 3.76, 9.96, 7.8, and 15.3 for pK/sub 1/ for pK/sub 2/, logk/sub 1/, and log..beta../sub 2/, respectively, and those for 6-benzylaminopurine were, in the same order, 3.90, 9.84, 8.3, and 15.9. The copper(II) complexes with kinetin and 6-benzylaminopurine had superoxide dismutase mimetic activity, and the reaction rate constants with superoxide, which were determined by polarography. were 2.3 x 10/sup 7/ M/sup -1/s/sup -1/ for kinetin and 1.5 x 10/sup 7/ M/sup -1/s/sup -1/ for 6-benzylaminopurine at pH 9.8 and 25/sup 0/C.

  16. Importance of hydrogen bonds to stabilities of copper water complexes

    Science.gov (United States)

    Sukrat, Kanjarat; Parasuk, Vudhichai

    2007-10-01

    An investigation of structures and stabilization energies of copper-water complexes is presented. Possible cluster geometries of [Cu(H 2O) n] 2+ for n = 1-8 were optimized using HF/6-31G(d,p), and energies were determined at the MP2/6-31G(d,p) and B3LYP/6-31G(d,p) levels of theory. In addition, for n = 6, 7, and 8 geometry optimizations at MP2/6-311g(d,p) have been carried out. The basis set effect on stabilization energies was also considered by performing MP2 with 6-31++G(d,p), 6-311G(d,p) and 6-311G(2df,p) single point energy calculations. Only five- and six-fold coordination complexes were obtained with square pyramid (spy) and octahedral (oct) copper coordination as their most stable structures. The hydrogen bonds which form between water molecules in the first and second solvation shell play an important role for the stabilities of the complexes.

  17. Complex strain paths in polycrystalline copper: microstructural aspects

    Directory of Open Access Journals (Sweden)

    M.F. Vieira

    1999-07-01

    Full Text Available Microstructural aspects of polycrystalline copper sheets subjected to complex strain paths were analysed in this work. Dislocation structures developed during the strain paths (rolling and tension and the evolution of this microstructure during reloading have been studied. The active slip systems developed in each strain path were used to explain the microstructural evolution. The heterogeneous surface deformation observed on polished tensile specimens prestrained in rolling was also analysed. The structural aspects are related with the mechanical behaviour of the material, namely with the increase in yield stress in reloading, the work hardening evolution and the premature occurrence of plastic instability for some prestrain values.

  18. Copper toxicity to larval stages of three marine invertebrates and copper complexation capacity in San Diego Bay, California.

    Science.gov (United States)

    Rivera-Duarte, Ignacio; Rosen, Gunther; Lapota, David; Chadwick, David B; Kear-Padilla, Lora; Zirino, Alberto

    2005-03-15

    Temporal and spatial measurements of the toxicity (EC50), chemical speciation, and complexation capacity (Cu-CC) of copper in waters from San Diego Bay suggest control of the Cu-CC over copper bioavailability. While spatial distributions of total copper (CuT) indicate an increase in concentration from the mouth toward the head of San Diego Bay, the distribution of aqueous free copper ion (Cu(II)aq) shows the opposite trend. This suggests that the bioavailability of copper to organisms decreases toward the head of the bay, and is corroborated by the increase in the amount of copper needed to reach an EC50, observed for larval stages of three marine invertebrates (Mediterranean mussel, Mytilus galloprovincialis, sand dollar, Dendraster excentricus, and purple sea urchin, Strongylocentrotus purpuratus), and by the increase in Cu-CC heading into the head of the bay. The amount of Cu(II)aq required to produce a 50% reduction in normal larval development (referred to here as pCuTox,) of the mussel, the most sensitive of the three marine invertebrates, was generally at or above approximately 1 x 10(-11) mol L(-1) equivalents of Cu (i.e., pCuTox approximately 11 = -(log [Cu(II)aq])). These results suggest that the copper complexation capacity in San Diego Bay controls copper toxicity by keeping the concentration of Cu(II)aq at nontoxic levels.

  19. Electrochemical synthesis and structural characterization of a novel mixed-valence copper(I)-copper(II) complex: {[bis(ethylenediamine)copper(II)] bis[diiodocuprate(I)]}.

    Science.gov (United States)

    Fotouhi, Lida; Dehghanpour, Saeed; Heravi, Majid M; Ardakani, Mahboobeh Dashti

    2007-07-12

    A novel, mixed-valent copper(I)-copper(II) complex, {[bis(ethylene-diamine)copper(II)] bis[diiodocuprate(I)]} (1), has been prepared by electrochemical dissolution of a sacrificial copper anode in a solution of ethylenediamine (en), I2 and tetraethylammoniumperchlorate (TEAP) as supporting electrolyte in acetonitrile (AcN)and characterized by single-crystal X-ray structure determination. The crystal structure of the complex 1 shows that it consists of a CuI2 polymer formed from I- ligands bridging Cu(I) ions, with a nearly square planar geometry of bivalent Cu(II) atoms chelated by two ethylenediamine ligands. The results also show that direct electrosynthesis of the complex had high current efficiency, purity and electrolysis yield.

  20. FTIR spectra and normal-mode analysis of a tetranuclear Manganese adamantane-like complex in two electrochemically prepared oxidation states: Relevance to the oxygen-evolving complex of Photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Hendrik; Dube, Christopher E.; Armstrong, William H.; Sauer, Kenneth; Yachandra, Vittal K.

    2002-03-19

    The IR spectra and normal-mode analysis of the adamantane-like compound [Mn4O6(bpea)4]n+ in two oxidation states, MnIV4 and MnIIIMnIV3, that are relevant to the oxygen-evolving complex of photosystem II are presented. Mn-O vibrational modes are identified with isotopic exchange, 16O->18O, of the mono-(mu)-oxo bridging atoms in the complex. IR spectra of the MnIIIMnIV3 species are obtained by electrochemical reduction of the MnIV4 species using a spectroelectrochemical cell, based on attenuated total reflection [Visser et al. Anal Chem 2001, 73, 4374-4378]. A novel method of subtraction is used to reduce background contributions from solvent and ligand modes, and the difference and double-difference spectra are used in identifying Mn-O bridging modes that are sensitive to oxidation state change. Two strong IR bands are observed for the MnIV4 species at 745 and 707 cm-1 and a weaker band at 510 cm-1. Upon reduction, the MnIIIMnIV3 species exhibits two strong IR bands at 745 and 680 cm-1, and several weaker bands are observed in the 510 - 425 cm-1 range. A normal mode analysis is performed to assign all the relevant bridging modes in the oxidized MnIV4 and reduced MnIIIMnIV3 species. The calculated force constants for the MnIV4 species are = 3.15 mdynAngstrom, = 0.55 mdyn/Angstrom, and = 0.20 mdyn/Angstrom. The force constants for the MnIIIMnIV3 species are = 3.10 mdyn/Angstrom, = 2.45 mdyn/Angstrom, = 0.40, and = 0.15 mdyn/Angstrom. This study provides insights for the identification of Mn-O modes in the IR spectra of the photosynthetic oxygen-evolving complex during its catalytic cycle.

  1. [Copper-induced change in the ESR signal of hemoglobin nitrosyl complexes in wound by the action of copper nanoparticles].

    Science.gov (United States)

    Volodina, L A; Baĭder, L M; Rakhmetova, A A; Bogoslovskaia, O A; Ol'khovskaia, I P; Glushchenko, N N

    2013-01-01

    The results concerning changes in the ESR signal of hemoglobin nitrosyl complexes in wound tissues in the course of healing by the action of ointments with copper nanoparticles (patent N2460532, Russia) are presented. It is shown that the wound healing process modified by the influence of copper nanoparticles demonstrates the increase in the ESR signal amplitude for :hemoglobin nitrosyl complexes as compared with controls (the ointment base without nanoparticles). Planimetric measurements of wound area through reparation course indicate an active process of wound healing for injuries treated with copper nanoparticles in the ointment, resulting in lessening half-reparation time up to 5.0 times as compared with controls (treatment with the ointment base). The paper discusses the role of copper nanoparticles, NO and their potential synergistic effect on the skin wound regeneration.

  2. Self-reduction of a copper complex MOD ink for inkjet printing conductive patterns on plastics.

    Science.gov (United States)

    Farraj, Yousef; Grouchko, Michael; Magdassi, Shlomo

    2015-01-31

    Highly conductive copper patterns on low-cost flexible substrates are obtained by inkjet printing a metal complex based ink. Upon heating the ink, the soluble complex, which is composed of copper formate and 2-amino-2-methyl-1-propanol, decomposes under nitrogen at 140 °C and is converted to pure metallic copper. The decomposition process of the complex is investigated and a suggested mechanism is presented. The ink is stable in air for prolonged periods, with no sedimentation or oxidation problems, which are usually encountered in copper nanoparticle based inks.

  3. Influence of Copper Oxidation State on the Bonding and Electronic Structure of Cobalt-Copper Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhart, Reed J.; Carlson, Rebecca K.; Clouston, Laura J.; Young, Jr., Victor G.; Chen, Yu-Sheng; Bill, Eckhard; Gagliardi, Laura; Lu, Connie C. (UC); (UMM); (MXPL)

    2016-03-04

    Heterobimetallic complexes that pair cobalt and copper were synthesized and characterized by a suite of physical methods, including X-ray diffraction, X-ray anomalous scattering, cyclic voltammetry, magnetometry, electronic absorption spectroscopy, electron paramagnetic resonance, and quantum chemical methods. Both Cu(II) and Cu(I) reagents were independently added to a Co(II) metalloligand to provide (py3tren)CoCuCl (1-Cl) and (py3tren)CoCu(CH3CN) (2-CH3CN), respectively, where py3tren is the triply deprotonated form of N,N,N-tris(2-(2-pyridylamino)ethyl)amine. Complex 2-CH3CN can lose the acetonitrile ligand to generate a coordination polymer consistent with the formula “(py3tren)CoCu” (2). One-electron chemical oxidation of 2-CH3CN with AgOTf generated (py3tren)CoCuOTf (1-OTf). The Cu(II)/Cu(I) redox couple for 1-OTf and 2-CH3CN is reversible at -0.56 and -0.33 V vs Fc+/Fc, respectively. The copper oxidation state impacts the electronic structure of the heterobimetallic core, as well as the nature of the Co–Cu interaction. Quantum chemical calculations showed modest electron delocalization in the (CoCu)+4 state via a Co–Cu σ bond that is weakened by partial population of the Co–Cu σ antibonding orbital. By contrast, no covalent Co–Cu bonding is predicted for the (CoCu)+3 analogue, and the d-electrons are fully localized at individual metals.

  4. CONSIDERATIONS ON THE INFLUENCE OF COMPLEXATION IN THE COPPER UPTAKE AND TRANSLOCATION

    Directory of Open Access Journals (Sweden)

    SEMAGHIUL BIRGHILA

    2014-07-01

    Full Text Available The actual knowledge about food and the environment underlines the fact that agricultural and environmental sciences must solve various problems regarding copper uptake from soil to plants and its bioaccumulation, being important issues for copper concentration in crops and also for phytoremediation of polluted soils. We studied the relation between the form in which copper is applied to soil and the consequential copper bioavailability, uptake and translocation, using as examples simple and complex copper compounds. The copper concentration in basil plants harvested from soils treated with copper compounds and the calculated values of transfer coefficient, translocation factor, bioaccumulation factor, and uptake coefficient demonstrated that the ionic copper (from simple salts is not necessarily easier to uptake than complex ions, but is easier translocated in plants, while the copper given as complex ions is most likely to be retained by roots. The results indicated that the involvement of copper complexes in agricultural treatments is a solution for soils phytoremediation, concerning the phytostabilization technology.

  5. Copper(II)–imida‐salen Complexes Encapsulated into NaY Zeolite for Oxidations Reactions

    DEFF Research Database (Denmark)

    Kuźniarska‐Biernacka, Iwona; Carvalho, M. Alice; Rasmussen, Søren Birk

    2013-01-01

    heterogeneous catalysts were characterized by SEM, XRD, FTIR, EPR and Raman spectroscopy as well as by chemical analysis. The structures of the copper(II) complexes were proposed on the basis of theoretical studies (DFT). The catalytic activities of the encapsulated copper(II) complexes in NaY were compared...

  6. Photocatalysis; IV. Preparation and characterization of a stable copper(I) triflate-trans-cycloheptene complex

    NARCIS (Netherlands)

    Evers, J.T.M.; Mackor, A.

    1979-01-01

    When copper(I) triflate·cis‐cycloheptene is irradiated at 254 nm in n‐hexane solution, cis → trans‐isomerization occurs and the stable complex copper (I) triflate·trans‐cycloheptene precipitates. This complex has been isolated, purified and characterized by elemental analysis and by its 1H and 13C

  7. Copper(II) Schiff base complexes and their mixed thin layers with ...

    Indian Academy of Sciences (India)

    the possibility of using the spin coating technique for deposition of the copper(II) complexes and ZnO nanoparticles on different substrates and the likely flu- orescence behavior of the obtained layers, prompted us to synthesize a series of new copper(II) complexes with. Schiff bases derived from ethylenediamine and several.

  8. Copper (II) Schiff base complexes and their mixed thin layers with ...

    Indian Academy of Sciences (India)

    Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles. MAGDALENA ... Keywords. Thin layer; ZnO nanoparticles; copper complexes; AFM; SEM; fluorescence. ... Zinc oxide was synthesized using a simple homogeneous precipitation method with zinc acetate as a starting material. Thin layers ...

  9. Copper(II) complexes with heterocyclic hydroxyimino-containing ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kogan, V.A.; Burlov, A.S.; Popov, L.D.; Lukov, V.V.; Koshchienko, Yu.V.; Tsupak, E.B.; Barchan, G.P.; Chigarenko, G.G.; Bolotnikov, V.S.

    1988-05-01

    The reaction of oximes (R = Ph (L'), C=N (L'')) with the copper(II) salts CuA/sub 2/ in methanol has given the complexes CuL/sub 2/ ' x H/sub 2/O and CuL/sub 2//sup ''/ x 2H/sub 2/O (I) (A = Acet/sup -/), CuHLCl/sub 2/ x H/sub 2/O (II) (A = Cl/sup -/), CuLOH(ClO/sub 4/)/sub 2/ x 2H/sub 2/O (III) (A = ClO/sub 4//sup -/) and the complexes Cu/sub 3/L/sub 3//sup '/OH(NO/sub 3/)/sub 2/ and Cu/sub 3/L/sub 3//sup ''/(OH)/sub 2/NO/sub 3/ (IV) (A = NO/sub 3//sup -/). Their physicochemical properties have been studied by the methods of IR spectroscopy and magnetochemistry. It has been shown that complexes I have a chelate structure and that their magnetic moments are not dependent on the temperature. An anti-ferromagnetic exchange interaction takes place in complexes II-IV. On the basis of magnetochemical measurements over a broad temperature range and data calculated in the framework of the Heisenberg-Dirac-Van Vleck model of isotropic exchange interactions, a dimeric structure has been proposed for the complexes of type II, and a trinuclear cluster structure has been proposed for complexes III and IV.

  10. Characterisation of covalent copper and manganese organometallic complexes with Schiff bases by ionspray mass spectrometry

    NARCIS (Netherlands)

    Raffaelli, A.; Minutolo, F.; Feringa, B.L.; Salvadori, P.

    1998-01-01

    Copper and manganese complexes containing Schiff bases as ligands, having potential interest in homogeneous catalysis, have been characterised by mass spectrometry using ionspray ionisation. Single stage mass spectrometry allowed us to confirm the molecular weight of complexes in all cases,

  11. Transition metal complexes of neocryptolepine analogues. Part I: Synthesis, spectroscopic characterization, and invitro anticancer activity of copper(II) complexes

    Science.gov (United States)

    Emam, Sanaa Moustafa; El Sayed, Ibrahim El Tantawy; Nassar, Nagla

    2015-03-01

    New generation of copper(II) complexes with aminoalkylaminoneocryptolepine as bidentate ligands has been synthesized and it is characterized by elemental analyses, magnetic moment, spectra (IR, UV-Vis, 1H NMR and ESR) and thermal studies. The IR data suggest the coordination modes for ligands which behave as a bidentate with copper(II) ion. Based on the elemental analysis, magnetic studies, electronic and ESR data, binuclear square planar geometry was proposed for complexes 7a, 7b, square pyramidal for 9a, 9b and octahedral for 8a, 8b, 10a, 10b. The molar conductance in DMF solution indicates that all complexes are electrolyte except 7a and 7b. The ESR spectra of solid copper(II) complexes in powder form showed an axial symmetry with 2B1g as a ground state and hyperfine structure. The thermal stability and degradation of the ligands and their metal complexes were studied employing DTA and TG methods. The metal-free ligands and their copper(II) complexes were tested for their in vitro anticancer activity against human colon carcinoma (HT-29). The results showed that the synthesized copper(II) complexes exhibited higher anticancer activity than their free ligands. Of all the studied copper(II) complexes, the bromo-substituted complex 9b exhibited high anticancer activity at low micromolar inhibitory concentrations (IC50 = 0.58 μM), compared to the other complexes and the free ligands.

  12. Polyethyleneimine anchored copper(II) complexes: synthesis, characterization, in vitro DNA binding studies and cytotoxicity studies.

    Science.gov (United States)

    Lakshmipraba, Jagadeesan; Arunachalam, Sankaralingam; Riyasdeen, Anvarbatcha; Dhivya, Rajakumar; Akbarsha, Mohammad Abdulkader

    2015-01-01

    The water soluble polyethyleneimine-copper(II) complexes, [Cu(phen)(L-tyr)BPEI]ClO4 (where phen=1,10-phenanthroline, L-tyr=L-tyrosine and BPEI=branched polyethyleneimine) with various degree of copper(II) complex units in the polymer chain were synthesized and characterized by elemental analysis and electronic, FT-IR, EPR spectroscopic techniques. The binding of these complexes with CT-DNA was studied using UV-visible absorption titration, thermal denaturation, emission, circular dichroism spectroscopy and cyclic voltammetric methods. The changes observed in the physicochemcial properties indicated that the binding between the polymer-copper complexes and DNA was mostly through electrostatic mode of binding. Among these complexes, the polymer-copper(II) complex with the highest degrees of copper(II) complex units (higher degrees of coordination) showed higher binding constant than those with lower copper(II) complex units (lower degrees of coordination) complexes. The complex with the highest number of metal centre bound strongly due to the cooperative binding effect. Therefore, anticancer study was carried out using this complex. The cytotoxic activity for this complex on MCF-7 breast cancer cell line was determined adopting MTT assay, acridine orange/ethidium bromide (AO/EB) staining and comet assay techniques, which revealed that the cells were committed to specific mode of cell death either apoptosis or necrosis. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Copper complexation screen reveals compounds with potent antibiotic properties against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Haeili, Mehri; Moore, Casey; Davis, Christopher J C; Cochran, James B; Shah, Santosh; Shrestha, Tej B; Zhang, Yaofang; Bossmann, Stefan H; Benjamin, William H; Kutsch, Olaf; Wolschendorf, Frank

    2014-07-01

    Macrophages take advantage of the antibacterial properties of copper ions in the killing of bacterial intruders. However, despite the importance of copper for innate immune functions, coordinated efforts to exploit copper ions for therapeutic interventions against bacterial infections are not yet in place. Here we report a novel high-throughput screening platform specifically developed for the discovery and characterization of compounds with copper-dependent antibacterial properties toward methicillin-resistant Staphylococcus aureus (MRSA). We detail how one of the identified compounds, glyoxal-bis(N4-methylthiosemicarbazone) (GTSM), exerts its potent strictly copper-dependent antibacterial properties on MRSA. Our data indicate that the activity of the GTSM-copper complex goes beyond the general antibacterial effects of accumulated copper ions and suggest that, in contrast to prevailing opinion, copper complexes can indeed exhibit species- and target-specific activities. Based on experimental evidence, we propose that copper ions impose structural changes upon binding to the otherwise inactive GTSM ligand and transfer antibacterial properties to the chelate. In turn, GTSM determines target specificity and utilizes a redox-sensitive release mechanism through which copper ions are deployed at or in close proximity to a putative target. According to our proof-of-concept screen, copper activation is not a rare event and even extends to already established drugs. Thus, copper-activated compounds could define a novel class of anti-MRSA agents that amplify copper-dependent innate immune functions of the host. To this end, we provide a blueprint for a high-throughput drug screening campaign which considers the antibacterial properties of copper ions at the host-pathogen interface. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  14. Copper Complexation Screen Reveals Compounds with Potent Antibiotic Properties against Methicillin-Resistant Staphylococcus aureus

    Science.gov (United States)

    Haeili, Mehri; Moore, Casey; Davis, Christopher J. C.; Cochran, James B.; Shah, Santosh; Shrestha, Tej B.; Zhang, Yaofang; Bossmann, Stefan H.; Benjamin, William H.

    2014-01-01

    Macrophages take advantage of the antibacterial properties of copper ions in the killing of bacterial intruders. However, despite the importance of copper for innate immune functions, coordinated efforts to exploit copper ions for therapeutic interventions against bacterial infections are not yet in place. Here we report a novel high-throughput screening platform specifically developed for the discovery and characterization of compounds with copper-dependent antibacterial properties toward methicillin-resistant Staphylococcus aureus (MRSA). We detail how one of the identified compounds, glyoxal-bis(N4-methylthiosemicarbazone) (GTSM), exerts its potent strictly copper-dependent antibacterial properties on MRSA. Our data indicate that the activity of the GTSM-copper complex goes beyond the general antibacterial effects of accumulated copper ions and suggest that, in contrast to prevailing opinion, copper complexes can indeed exhibit species- and target-specific activities. Based on experimental evidence, we propose that copper ions impose structural changes upon binding to the otherwise inactive GTSM ligand and transfer antibacterial properties to the chelate. In turn, GTSM determines target specificity and utilizes a redox-sensitive release mechanism through which copper ions are deployed at or in close proximity to a putative target. According to our proof-of-concept screen, copper activation is not a rare event and even extends to already established drugs. Thus, copper-activated compounds could define a novel class of anti-MRSA agents that amplify copper-dependent innate immune functions of the host. To this end, we provide a blueprint for a high-throughput drug screening campaign which considers the antibacterial properties of copper ions at the host-pathogen interface. PMID:24752262

  15. Preparation, characterization and biological evaluation of copper(II) and zinc(II) complexes with cephalexin.

    Science.gov (United States)

    Iqbal, M S; Ahmad, A R; Sabir, M; Asad, S M

    1999-04-01

    Copper(II) and zinc(II) complexes of cephalexin have been prepared and characterized by microanalysis and by thermogravimetric, magnetic and spectroscopic analysis. The complexes were found to be five-coordinate, monohydrate, and ML2 type. The electron paramagnetic resonance spectral lines revealed rhombic distortion from axial symmetry, with g(parallel) > g(perpendicular) > g(e), in the elongated-tetragonal copper(II) complex. The geometry of the zinc(II) complex seems to be square-pyramidal. On complexation with copper and zinc the antimicrobial activity of cephalexin improved significantly. The copper complex was found to be active against kaolin paw oedema whereas the parent drug was inactive. These results suggest that the metallic elements should be seriously considered during drug design, and that complexes already reported should be subjected to clinical evaluation. Their use could provide an easy way of improving the activity and reducing the toxicity of drug substances.

  16. Inhibitory effect of Disulfiram/copper complex on non-small cell lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Lincan [Department of Thoracic Surgery, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Shen, Hongmei [Cancer Center of Integrative Medicine, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Zhao, Guangqiang [Department of Thoracic Surgery, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Yang, Runxiang [Cancer Chemotherapy Center, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Cai, Xinyi [Colorectal Cancer Center, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Zhang, Lijuan [Department of Pathology, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Jin, Congguo [Cancer Institute, The Third Affiliated Hospital of Kunming Medical University, Kunming (China); Huang, Yunchao, E-mail: daliduanlincan@163.com [Department of Thoracic Surgery, The Third Affiliated Hospital of Kunming Medical University, Kunming (China)

    2014-04-18

    Highlights: • Disulfiram and copper synergistically inhibit lung cancer cell proliferation. • Lung cancer cell colony formation ability is inhibited by Disulfiram/copper. • Disulfiram/copper increases the sensitivity of cisplatin to lung cancer cells. • Lung cancer stem cells are specifically targeted by Disulfiram/copper complex. - Abstract: Non-small cell lung cancer (NSCLC) is the most common cause of cancer-related death in both men and women worldwide. Recently, Disulfiram has been reported to be able to inhibit glioblastoma, prostate, or breast cancer cell proliferation. In this study, the synergistic effect of Disulfiram and copper on NSCLC cell growth was investigated. Inhibition of cancer cell proliferation was detected by 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT) assay and cell cycle analysis. Liquid colony formation and tumor spheroid formation assays were used to evaluate their effect on cancer cell clonogenicity. Real-time PCR was performed to test the mRNA level of cancer stem cell related genes. We found that Disulfiram or copper alone did not potently inhibit NSCLC cell proliferation in vitro. However, the presence of copper significantly enhanced inhibitory effect of Disulfiram on NSCLC cell growth, indicating a synergistic effect between Disulfiram and copper. Cell cycle analysis showed that Disulfiram/copper complex caused NSCLC cell cycle arrest in G2/M phase. Furthermore, Disulfiram/copper significantly increased the sensitivity of cisplatin in NSCLC cells tested by MTT assay. Liquid colony formation assay revealed that copper dramatically increased the inhibitory effect of Disulfiram on NSCLC cell colony forming ability. Disulfiram combined with copper significantly attenuated NSCLC cell spheroid formation and recuded the mRNA expression of lung cancer stem cell related genes. Our data suggest that Disulfiram/copper complex alone or combined with other chemotherapy is a potential therapeutic strategy for NSCLC patients.

  17. Catalytic aspects of a copper(II) complex: biological oxidase to ...

    Indian Academy of Sciences (India)

    BISWAJIT CHOWDHURY

    2017-10-03

    Oct 3, 2017 ... assigned to the ligand field transition for the copper(II) complex. The X-band EPR spectrum of the copper com- plex (Figure S2 in SI) at low temperature (LT, 77K) was recorded in frozen MeCN solution (Figure S2 (Left)) and in powder state at 77 K (Figure S2 (Right) in SI) to examine the geometry of copper ...

  18. Microstructural Evolution of a Nanostructured Complex Copper Alloy Processed by Accumulative Roll-Bonding of Oxygen Free Copper and DLP.

    Science.gov (United States)

    Lee, Seong-Hee; Lee, Seong Ro; Ahn, In-Sook; Lim, Cha-Yong

    2016-02-01

    The accumulative roll-bonding (ARB) process using different copper alloys of oxygen free copper (OFC) and dioxide low-phosphorous copper (DLPC) was performed up to six cycles at ambient temperature without lubrication. A complex copper alloy sheet'in which OFC and DLPC alloys are stacked alternately each other was successfully fabricated by the ARB process. The microstructural evolution and texture development of the complex copper alloy with proceeding of the ARB were investigated by electron back scatter diffraction (EBSD) measurement. The specimen after 1 cycle showed significantly inhomogeneous microstructure in thickness direction, however, the inhomogeneity decreased gradually with increasing the number of ARB cycles. In addition, the grains became finer with the proceeding of the ARB. Resultantly, after 6 cycles, the specimen exhibited an ultrafine grained structure in which the grains above 65% were surrounded by the high angle grain boundaries above 15 degrees. On the other hand, there was no difference in texture development between OFC and DLPC in almost all specimens. In addition, the texture development did not depend on positions in thickness direction; the rolling texture such as {112} and {011} components developed strongly at all regions.

  19. X-ray structure of physiological copper(II)-bis(L-histidinato) complex.

    Science.gov (United States)

    Deschamps, Patrick; Kulkarni, Prasad P; Sarkar, Bibudhendra

    2004-05-31

    The isolation and the X-ray crystal structure of physiological copper(II)-L-histidine complex are reported. The neutral five-coordinate complex shows distorted square pyramidal geometry with bidentate and tridentate L-histidine ligands. The basic character of the pendent imidazole group and H-bonding interactions of bidentate L-histidine ligand are important for copper transport. The unique structural features help explain the origin of its thermodynamic stability and kinetic reactivity in human blood along with the ternary copper(II)-amino acid complexes. The role of L-histidine in interaction with copper(II)-albumin, in cellular uptake of copper, and in treatment of Menkes disease can be studied using these results.

  20. Tridentate copper ligand influences on heme-peroxo-copper formation and properties: reduced, superoxo, and mu-peroxo iron/copper complexes.

    Science.gov (United States)

    Kim, Eunsuk; Helton, Matthew E; Lu, Shen; Moënne-Loccoz, Pierre; Incarvito, Christopher D; Rheingold, Arnold L; Kaderli, Susan; Zuberbühler, Andreas D; Karlin, Kenneth D

    2005-10-03

    In cytochrome c oxidase synthetic modeling studies, we recently reported a new mu-eta2:eta2-peroxo binding mode in the heteronuclear heme/copper complex [(2L)Fe(III)-(O2(2-))-CuII]+ (6) which is effected by tridentate copper chelation (J. Am. Chem. Soc. 2004, 126, 12716). To establish fundamental coordination and O2-reactivity chemistry, we have studied and describe here (i) the structure and dioxygen reactivity of the copper-free compound (2L)FeII (1), (ii) detailed spectroscopic properties of 6 in comparisons with those of known mu-eta2:eta1 heme-peroxo-copper complexes, (iii) formation of 6 from the reactions of [(2L)FeIICuI]+ (3) and dioxygen by stopped-flow kinetics, and (iv) reactivities of 6 with CO and PPh3. In the absence of copper, 1 serves as a myoglobin model compound possessing a pyridine-bound five-coordinate iron(II)-porphyrinate which undergoes reversible dioxygen binding. Oxygenation of 3 below -60 degrees C generates the heme-peroxo-copper complex 6 with strong antiferromagnetic coupling between high-spin iron(III) and copper(II) to yield an S = 2 spin system. Stopped-flow kinetics in CH2Cl2/6% EtCN show that dioxygen reacts with iron(II) first to form a heme-superoxide moiety, [(EtCN)(2L)FeIII-(O2-)...CuI(EtCN)]+ (5), which further reacts with Cu(I) to generate 6. Compared to those properties of a known mu-eta2:eta1-heme-peroxo-copper complex, 6 has a significantly diminished resonance Raman nu(O-O) stretching frequency at 747 cm(-1) and distinctive visible absorptions at 485, 541, and 572 nm, all of which seem to be characteristics of a mu-eta2:eta2-heme-peroxo-copper system. Addition of CO or PPh3 to 6 yields a bis-CO adduct of 3 or a PPh(3) adduct of 5, the latter with a remaining FeIII-(O2-) moiety.

  1. Synthesis of Hetero- and Homo-multinuclear Complexes with a Tetracyanonickelate Anion: Structural Characterization [Cu(bcen)Ni(CN)4]2.

    Science.gov (United States)

    Vafazadeh, Rasoul; Dehghani-Firouzabadi, Amin; Willis, C Anthony

    2017-09-01

    Two new complexes [Cu(bcen)Ni(CN)4]2 (1) and [Ni(bcen)Ni(CN)4] (2) where bcen is 4,7-diazadecanediamide, were synthesized by reaction of equimolar amounts of M(NO3)2 (M = Cu and Ni), bcen ligand and K2[Ni(CN)4]. Single-crystal X-ray diffraction analysis of compound 1, shows that the bcen ligand acts as a tridentate chelate, coordinating to the Cu(II) ion via the two nitrogen atoms of the amine groups and one oxygen atom of one amide group, and the other amide unit is left uncoordinated. The coordination geometry around the Cu(II) ions is five coordinate with a distorted square pyramid geometry, comprising two nitrogen atoms and one oxygen atom belonging to the bcen ligand and two nitrogen atoms of the cyano groups of two Ni(CN)4 2- units. The distance between the copper ion and the amide oxygen of the dangling arm of an adjacent tetranuclear species is within the expected range for an axial Cu-O bond, and hence suggests that the amide oxygen of an adjacent tetranuclear complex may weakly coordinate to the copper ion in an axial position. These contacts link the tetranuclear species into infinite chain polymers.

  2. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Science.gov (United States)

    2010-04-01

    ... pyrophosphate. Sorbitol. Magnesium phosphate, tribasic. Calcium carbonate. Calcium phosphate, dibasic. Sodium N... specifications to the requirements of § 73.1125(a)(1) and (b). (b) Uses and restrictions. Potassium sodium copper...

  3. Complexation between the fungicide tebuconazole and copper(II) probed by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Dytrtová, Jana Jaklová; Jakl, Michal; Schröder, Detlef; Čadková, Eva; Komárek, Michael

    2011-04-30

    Electrospray ionization mass spectrometry (ESI-MS) is used to probe the complex formation between tebuconazole (1) and copper(II) salts, which both are commonly used fungicides in agriculture. Experiments with model solutions containing 1 and CuCl(2) reveal the initial formation of the copper(II) species [(1)CuCl](+) and [(1)(2)CuCl](+) which undergo reduction to the corresponding copper(I) ions [(1)Cu](+) and [(1)(2)Cu](+) under more drastic ionization conditions in the ESI source. In additional experiments, copper/tebuconazole complexes were also detected in samples made from soil solutions of various origin and different amount of mineralization. The direct sampling of such solutions via ESI-MS is thus potentially useful for understanding of the interactions between copper(II) salts and tebuconazole in environmental samples. Copyright © 2011 John Wiley & Sons, Ltd.

  4. Spectral studies of copper(II) complexes of 6-(3-thienyl) pyridine-2-thiosemicarbazone

    Science.gov (United States)

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-01

    Two novel copper(II) complexes [Cu(HL)Cl]Cl˙H2O (1) and [Cu(L)NO3]˙H2O (2) of the three NNS donor thiosemicarbazone ligand 6-(3-thienyl) pyridine-2-thiosemicarbazone have been synthesized. The ligand and its copper(II) complexes were characterized by elemental analysis (C, H, N, and S), FT-IR, UV-visible, magnetic susceptibility and molar conductance. The thiosemicarbazone is present either as the thione form in complex 1 or as thiol form in complex 2 and is coordinated to copper(II) atom via the pyridine nitrogen atom, the azomethine nitrogen atom and the sulfur atom. The physicochemical and spectral data suggest square planar geometry for copper(II) atoms.

  5. Calcium release induced by 2-pyridinecarboxaldehyde thiosemicarbazone and its copper complex contributes to tumor cell death.

    Science.gov (United States)

    Fu, Yun; Liu, Youxun; Wang, Jiangang; Li, Cuiping; Zhou, Sufeng; Yang, Yun; Zhou, Pingxin; Lu, Chengbiao; Li, Changzheng

    2017-03-01

    Thiosemicarbazones display significant antitumor activity and their copper complexes also exhibit enhanced biological activities in most situations, but the underlying mechanism is poorly understood. Therefore, investigation of the mechanism involved in the change upon chelation is required to extend our understanding of the effects of thiosemicarbazones. In the present study, the inhibitory effect of 2-pyridinecarboxaldehyde thiosemicarbazone (PCT) and its copper complex (PCT-Cu) on cell proliferation was investigated. The copper chelate exhibited a 3- to 10-fold increase in antitumor activity (with an IC50 thiosemicarbazones along with their antitumor mechanism.

  6. Synthetic bioactive novel ether based Schiff bases and their copper(II) complexes

    Science.gov (United States)

    Shabbir, Muhammad; Akhter, Zareen; Ismail, Hammad; Mirza, Bushra

    2017-10-01

    Novel ether based Schiff bases (HL1- HL4) were synthesized from 5-chloro-2-hydroxy benzaldehyde and primary amines (1-amino-4-phenoxybenzene, 4-(4-aminophenyloxy) biphenyl, 1-(4-aminophenoxy) naphthalene and 2-(4-aminophenoxy) naphthalene). From these Schiff bases copper(II) complexes (Cu(L1)2-Cu(L4)2)) were synthesized and characterized by elemental analysis and spectroscopic (FTIR, NMR) techniques. The synthesized Schiff bases and copper(II) complexes were further assessed for various biological studies. In brine shrimp assay the copper(II) complexes revealed 4-fold higher activity (LD50 3.8 μg/ml) as compared with simple ligands (LD50 12.4 μg/ml). Similar findings were observed in potato disc antitumor assay with higher activities for copper(II) complexes (IC50 range 20.4-24.1 μg/ml) than ligands (IC50 range 40.5-48.3 μg/ml). DPPH assay was performed to determine the antioxidant potential of the compounds. Significant antioxidant activity was shown by the copper(II) complexes whereas simple ligands have shown no activity. In DNA protection assay significant protection behavior was exhibited by simple ligand molecules while copper(II) complexes showed neutral behavior (neither protective nor damaging).

  7. Synthesis, characterization and biological studies of copper(II) complexes with 2-aminobenzimidazole derivatives

    Science.gov (United States)

    Joseph, J.; Suman, A.; Nagashri, K.; Joseyphus, R. Selwin; Balakrishnan, Nisha

    2017-06-01

    Novel series of four copper(II) complexes with 2-aminobenzimidazole derivatives (obtained from the Knoevenagel condensate of acetylacetone (obtained from acetylacetone and halogen substituted benzaldehydes) and 2-aminobenzimidazole) were synthesized. They were structurally characterized using elemental analysis, molar conductance, FAB mass, FT- IR, 1H &13C-NMR, UV-Vis., and EPR techniques. On the basis of analytical and spectral studies, the distorted square planar geometry was assigned for all the complexes. The antibacterial screening of the ligands and their copper complexes indicated that all the complexes showed higher anti microbial activities than the free ligands. Superoxide dismutase and antioxidant activities of the copper complexes have also been performed. In the electrochemical technique, the shift in ΔEp, E1/2 and Ipc values were explored for the interaction of the complexes with CT-DNA. During the electrolysis process, the present ligand system stabilizes unusual oxidation state of copper in the complexes. It is believed that the copper complexes with curcumin analogs may enhance chemotherapeutic behavior.

  8. Tripodal bis(imidazole) thioether copper(I) complexes: mimics of the Cu(M) site of copper hydroxylase enzymes.

    Science.gov (United States)

    Zhou, Lei; Powell, Douglas; Nicholas, Kenneth M

    2007-09-17

    Tripodal bis(imidazole) thioether ligands, (N-methyl-4,5-diphenyl-2-imidazolyl)2C(OR)C(CH3)2SR' (BIT(OR,SR'); R = H, CH3; R' = CH3, C(CH3)3, C(C6H5)3), have been prepared, offering the same N2S donor atom set as the CuM binding site of the hydroxylase enzymes, dopamine beta hydroxylase and peptidylglycine hydroxylating monooxygenase. Isolable copper(I) complexes of the type [(BIT(OR,SMe))Cu(CO)]PF6 (3a and 3b) are produced in reactions of the respective tripodal ligands 1a (R = H) and 1b (R = Me) with [Cu(CH3CN)4]PF6 in CH2Cl2 under CO (1 atm); the pyramidal structure of 3a has been determined crystallographically. The infrared (IR) nu(CO)'s of 3a and 3b (L = CO) are comparable to those of the Cu(M)-carbonylated enzymes, indicating similar electronic character at the copper centers. The reaction of [(BIT(OH,SMe))Cu(CH3CN)]PF6 (2a) with dioxygen produces [(BIT(O,SOMe))2Cu2(DMF)2](PF6)2 (4), whose X-ray structure revealed the presence of bridging BIT-alkoxo ligands and terminal -SOMe groups. In contrast, oxygenation of 2b (R = Me) affords crystallographically defined [(BIT(OMe,SMe))2Cu2(mu-OH)2](OTf)2 (5), in which the copper centers are oxygenated without accompanying sulfur oxidation. Complex 5 in DMF is transformed into five-coordinate, mononuclear [CuII(BIT(OMe,SMe))(DMF)2](PF6)2 (6). The sterically hindered BIT(OR,SR') ligands 9 and 10 (R' = t-Bu; R = H, Me) and 11 and 12 (R' = CPh3; R = H, Me) were also prepared and examined for copper coordination/oxygenation. Oxygenation of copper(I) complex 13b derived from the BIT(OMe,SBu-t) ligand is slow, relative to 2b, producing a mixture of (BIT(OMe,SBu-t))2Cu2(mu-OH)2-type complexes 14b and 15b in which the -SBu-t group is uncoordinated; one of these complexes (15b) has been ortho-oxygenated on a neighboring aryl group according to the X-ray analysis and characterization of the free ligand. Oxygenation of the copper(I) complex derived from BIT(OMe,SCPh3) ligand 12 produces a novel dinuclear disulfide complex, [(BIT

  9. EPR study on copper- and vanadium complexes with substituted phthalocyanines

    Energy Technology Data Exchange (ETDEWEB)

    Shklyaev, A.A.; Selyutin, G.E.; Shakot' ko, N.I.; Mikhalenko, S.A. (Nauchno-Issledovatel' skij Inst. Organicheskikh Poluproduktov i Krasitelej, Moscow (USSR))

    1984-06-01

    The structure of binuclear associates of substituted vanadyl- and copper-phthalocyanines is investigated. The EPR study has shown that metal phthalocyanine protonation in acid media (CH/sub 2/Cl/sub 2/, Py, H/sub 2/SO/sub 4/, toluence, etc) is accompanied by destabilization of bonds of the central ion with a polycyclic ligand. Substituted copper- and vanadyl phthalocyanines form dimerized associates where M-M interatmic distance varies in a wide range from 4.1 to 12 A.

  10. Activation of dioxygen by copper metalloproteins and insights from model complexes.

    Science.gov (United States)

    Quist, David A; Diaz, Daniel E; Liu, Jeffrey J; Karlin, Kenneth D

    2017-04-01

    Nature uses dioxygen as a key oxidant in the transformation of biomolecules. Among the enzymes that are utilized for these reactions are copper-containing metalloenzymes, which are responsible for important biological functions such as the regulation of neurotransmitters, dioxygen transport, and cellular respiration. Enzymatic and model system studies work in tandem in order to gain an understanding of the fundamental reductive activation of dioxygen by copper complexes. This review covers the most recent advancements in the structures, spectroscopy, and reaction mechanisms for dioxygen-activating copper proteins and relevant synthetic models thereof. An emphasis has also been placed on cofactor biogenesis, a fundamentally important process whereby biomolecules are post-translationally modified by the pro-enzyme active site to generate cofactors which are essential for the catalytic enzymatic reaction. Significant questions remaining in copper-ion-mediated O2-activation in copper proteins are addressed.

  11. Well-Defined Copper(I) Fluoroalkoxide Complexes for Trifluoroethoxylation of Aryl and Heteroaryl Bromides

    KAUST Repository

    Huang, Ronglu

    2015-03-17

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Copper(I) fluoroalkoxide complexes bearing dinitrogen ligands were synthesized and the structure and reactivity of the complexes toward trifluoroethoxylation, pentafluoropropoxylation, and tetrafluoropropoxylation of aryl and heteroaryl bromides were investigated. Efficiency drive: A series of copper(I) fluoroalkoxide complexes bearing N,N ligands have been prepared and structurally characterized. These well-defined complexes serve as efficient reagents for the fluoroalkoxylation of aryl and heteroaryl bromides to produce a wide range of trifluoroethyl, pentafluoropropyl, and tetrafluoropropyl (hetero)aryl ethers in good to excellent yields.

  12. EXAFS study of mixed ligand copper complexes having nicotinic acid as one of the ligands

    Science.gov (United States)

    Joshi, S. K.; Gaur, A.; Shrivastava, B. D.; Gaur, D. C.; Prasad, J.; Srivastava, K.; Jha, S. N.; Bhattacharyya, D.; Poswal, A.

    2013-04-01

    Copper K-edge EXAFS spectra of the copper (II) complexes [Cu3(NA)4(dca)2(H2O)8].2H2O (1) and [Cu2(2,2'-bipy)(NA)2](ClO4)2.H2O (2) (where NA = Nicotinic acid; dca = dicyanamide anion; 2,2'-bipy = 2-2' bipyridine) having different coordination environments and geometries have been investigated. The complex 1 is supposed to have six coordinated geometry and complex 2 five coordinated geometry. EXAFS has been recorded at the K-edge of copper in the complex at the dispersive EXAFS beamline at 2 GeV Indus-2 synchrotron source at RRCAT, Indore, India. Theoretical models have been generated for both the complexes separately using their reported crystal structures. These theoretical models have been fitted to the respective experimental EXAFS data and the structural parameters, which include bond lengths, coordination numbers and thermal disorders, have been determined. The results obtained have been found to be comparable with those reported using crystallography. The coordination geometry about the copper (II) ion has been depicted for both the complexes. Further, copper has been found to be in +2 oxidation state in both the complexes. The study shows that the dispersive EXAFS beamline can be used to obtain information about the coordination geometry of a sample, though the beamline provides limited range of EXAFS data.

  13. Potentiometric studies of the complexes formed by copper (II) and ...

    African Journals Online (AJOL)

    The overall stability constants of copper (II) and zinc (II) ions with some polar uncharged amino acids including proline, threonine and asparagines were determined by potentiometric titration in aqueous solution. The values of the constants were found using ORIGIN 50 program computational method of analysis to be 19.56, ...

  14. Copper complexation by tannic acid in aqueous solution

    NARCIS (Netherlands)

    Kraal, P.; Jansen, B.; Nierop, K.G.J.; Verstraten, J.M.

    2006-01-01

    The speciation of titrated copper in a dissolved tannic acid (TA) solution with an initial concentration of 4 mmol organic carbon ((OC)/l was investigated in a nine-step titration experiment (Cu/oC molar ratio = 0.0030-0.0567). We differentiated between soluble and insoluble Cu species by 0.45 mu m

  15. Copper Complexes of Nicotinic-Aromatic Carboxylic Acids as Superoxide Dismutase Mimetics

    Directory of Open Access Journals (Sweden)

    Virapong Prachayasittikul

    2008-12-01

    Full Text Available Nicotinic acid (also known as vitamin B3 is a dietary element essential for physiological and antihyperlipidemic functions. This study reports the synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids (phthalic, salicylic and anthranilic acids. The tested copper complexes exhibited superoxide dismutase (SOD mimetic activity and antimicrobial activity against Bacillus subtilis ATCC 6633, with a minimum inhibition concentration of 256 μg/mL. Copper complex of nicotinic-phthalic acids (CuNA/Ph was the most potent with a SOD mimetic activity of IC50 34.42 μM. The SOD activities were observed to correlate well with the theoretical parameters as calculated using density functional theory (DFT at the B3LYP/LANL2DZ level of theory. Interestingly, the SOD activity of the copper complex CuNA/Ph was positively correlated with the electron affinity (EA value. The two quantum chemical parameters, highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO, were shown to be appropriate for understanding the mechanism of the metal complexes as their calculated energies show good correlation with the SOD activity. Moreover, copper complex with the highest SOD activity were shown to possess the lowest HOMO energy. These findings demonstrate a great potential for the development of value-added metallovitamin-based therapeutics.

  16. Mixed-ligand complexes of copper (II with ditiolfenols and heterocyclic diamines

    Directory of Open Access Journals (Sweden)

    K. A. Kuliev

    2017-01-01

    Full Text Available By the methods spectrophotometric methods was investigated complex formation of copper with 2,6-ditiolphenol and its derivatives (2,6-ditiol-4-methylphenol, 2,6-ditiol-4-ethylphenol and 2,6-ditiol-4-tert-buthylphenol in the presence of heterocyclic diamines. As heterocyclic diamines phenantroline (Fen, batophenantroline and dipyridile were used. It was established, that mixedligand complex were formed in weak acidic medium (pHop=6,0-8,5. Maximum of light absorption observed at (=522–550 nm. Molar coefficient of light absorption was ( = (3.08–4.92?104. The stoichiometry of complexes had been discovered using shift the equilibrium and relative yield methods. During the extraction of copper(II complexes with ditiol-phenols with the presence of heterocyclic diamines there was discovered that there is no chlorophorm molecules in the composition of the extracted complexes. IR spectra shows that hydroxyl group is involved to the formation of a bond with the metal and that phenantroline is included in the composition of the copper complex. In the organic phase mixed-ligand complexes have the monomeric form and can’t polymerize; that fact can be proved by calculations. By dint of spectrophotometric, IR-spectroscopic, thermogravimetric experiments and some published data we were able to determine the structural formula of complexes. Also had been determined main spectrophotometric characteristics of copper(II mixed-ligand complexes: pH of the beginning of the deposition, optimal pH, detection limit and sensivity. For separation and finding copper, we studied the effect of interfering foreign ions: alkali, alkaline earth and rare earth elements, as well as acid anions selected masking reagents. On the base of the results was offered photometric method for determination of copper in steel different trade-marks and in food. This method characterized by good reproduction (relatively standard deviation no more 0.05 and low limit of discovery.

  17. Reactivity of copper-α-synuclein peptide complexes relevant to Parkinson's disease.

    Science.gov (United States)

    Dell'Acqua, Simone; Pirota, Valentina; Anzani, Cecilia; Rocco, Michela M; Nicolis, Stefania; Valensin, Daniela; Monzani, Enrico; Casella, Luigi

    2015-07-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by the presence of abnormal α-synuclein (αSyn) deposits in the brain. Alterations in metal homeostasis and metal-induced oxidative stress may play a crucial role in the aggregation of αSyn and, consequently, in the pathogenesis of PD. We have therefore investigated the capability of copper-αSyn6 and copper-αSyn15 peptide complexes, with the 1-6 and 1-15 terminal fragments of the protein, to promote redox reactions that can be harmful to other cellular components. The pseudo-tyrosinase activity of copper-αSyn complexes against catecholic (di-tert-butylcatechol (DTBCH2), 4-methylcatechol (4-MC)) and phenolic (phenol) substrates is lower compared to that of free copper(II). In particular, the rates (kcat) of DTBCH2 catalytic oxidation are 0.030 s(-1) and 0.009 s(-1) for the reaction promoted by free copper(II) and [Cu(2+)-αSyn15], respectively. On the other hand, HPLC/ESI-MS analysis of solutions of αSyn15 incubated with copper(II) and 4-MC showed that αSyn is competitively oxidized with remarkable formation of sulfoxide at Met1 and Met5 residues. Moreover, the sulfoxidation of methionine residues, which is related to the aggregation of αSyn, also occurs on peptides not directly bound to copper, indicating that external αSyn can also be oxidized by copper. Therefore, this study strengthens the hypothesis that copper plays an important role in oxidative damage of αSyn which is proposed to be strongly related to the etiology of PD.

  18. X-RAY ABSORPTION FINE STRUCTURE (XAFS) STUDIES OF SOME COPPER COMPOUNDS AND COMPLEXES OF BIOLOGICAL IMPORTANCE

    OpenAIRE

    Gaur, Abhijeet

    2012-01-01

    In the present thesis, the X-ray absorption fine structure (XAFS)spectroscopy has been used to study copper compounds and complexes. Studies have been done using both EXAFS and XANES spectroscopies. Basically, following two types of studies have been made. Firstly, EXAFS study at the K-edge of copper in mixed ligand copper complexes of biological significance have been done to yield useful and important information about the molecular structure of the complexes which are mononuclear, bi...

  19. Orientation of the tetranuclear manganese cluster and tyrosine Z in the O(2)-evolving complex of photosystem II: An EPR study of the S(2)Y(Z)(*) state in oriented acetate-inhibited photosystem II membranes.

    Science.gov (United States)

    Lakshmi, K V; Eaton, S S; Eaton, G R; Brudvig, G W

    1999-09-28

    Inhibitory treatment by acetate, followed by illumination and rapid freezing, is known to trap the S(2)Y(Z)(*) state of the O(2)-evolving complex (OEC) in photosystem II (PS II). An EPR spectrum of this state exhibits broad split signals due to the interaction of the tyrosyl radical, Y(Z)(*), with the S = 1/2 S(2) state of the Mn(4) cluster. We present a novel approach to analyze S(2)Y(Z)(*) spectra of one-dimensionally (1-D) oriented acetate-inhibited PS II membranes to determine the magnitude and relative orientation of the S(2)Y(Z)(*) dipolar vector within the membrane. Although there exists a vast body of EPR data on isolated spins in oriented membrane sheets, the present study is the first of its kind on dipolar-coupled electron spin pairs in such systems. We demonstrate the feasibility of the technique and establish a rigorous treatment to account for the disorder present in partially oriented 1-D membrane preparations. We find that (i) the point-dipole distance between Y(Z)(*) and the Mn(4) cluster is 7.9 +/- 0.2 A, (ii) the angle between the interspin vector and the thylakoid membrane normal is 75 degrees, (iii) the g(z)()-axis of the Mn(4) cluster is 70 degrees away from the membrane normal and 35 degrees away from the interspin vector, and (iv) the exchange interaction between the two spins is -275 x 10(-)(4) cm(-)(1), which is antiferromagnetic. Due to the sensitivity of EPR line shapes of oriented spin-coupled pairs to the interspin distance, the present study imposes a tighter constraint on the Y(Z)-Mn(4) point-dipole distance than obtained from randomly oriented samples. The geometric constraints obtained from the 1-D oriented sample are combined with published models of the structure of Mn-depleted PS II to propose a location of the Mn(4) cluster. A structure in which Y(Z) is hydrogen bonded to a manganese-bound hydroxide ligand is consistent with available data and favors maximal orbital overlap between the two redox center that would facilitate

  20. Copper dopamine complex induces mitochondrial autophagy preceding caspase-independent apoptotic cell death.

    Science.gov (United States)

    Paris, Irmgard; Perez-Pastene, Carolina; Couve, Eduardo; Caviedes, Pablo; Ledoux, Susan; Segura-Aguilar, Juan

    2009-05-15

    Parkinsonism is one of the major neurological symptoms in Wilson disease, and young workers who worked in the copper smelting industry also developed Parkinsonism. We have reported the specific neurotoxic action of copper dopamine complex in neurons with dopamine uptake. Copper dopamine complex (100 microm) induces cell death in RCSN-3 cells by disrupting the cellular redox state, as demonstrated by a 1.9-fold increase in oxidized glutathione levels and a 56% cell death inhibition in the presence of 500 microm ascorbic acid; disruption of mitochondrial membrane potential with a spherical shape and well preserved morphology determined by transmission electron microscopy; inhibition (72%, p copper dopamine complex induces mitochondrial autophagy followed by caspase-3-independent apoptotic cell death. However, a different cell death mechanism was observed when 100 microm copper dopamine complex was incubated in the presence of 100 microm dicoumarol, an inhibitor of NAD(P)H quinone:oxidoreductase (EC 1.6.99.2, also known as DT-diaphorase and NQ01), because a more extensive and rapid cell death was observed. In addition, cyclosporine A had no effect on phosphatidylserine externalization, significant portions of compact chromatin were observed within a vacuolated nuclear membrane, DNA laddering was less pronounced, the mitochondria morphology was more affected, and the number of cells with autophagic vacuoles was a near 4-fold less.

  1. Hybrid copper complex-derived conductive patterns printed on polyimide substrates

    Science.gov (United States)

    Lee, Byoungyoon; Jeong, Sooncheol; Kim, Yoonhyun; Jeong, Inbum; Woo, Kyoohee; Moon, Jooho

    2012-06-01

    We synthesized new copper complexes that can be readily converted into highly conductive Cu film. Mechanochemical milling of copper (I) oxide suspended in formic acid resulted in the submicron-sized Cu formate together Cu nanoparticles. The submicrometer-sized Cu formates are reactive toward inter-particle sintering and metallic Cu seeds present in the Cu complexes assist their decomposition and the nucleation of Cu. The hybrid copper complex film printed on polyimide substrate is decomposed into dense and uniform Cu layer after annealing at 250 °C for 30 min under nitrogen atmosphere. The resulting Cu film exhibited a low resistivity of 8.2 μΩ·cm and good adhesion characteristics.

  2. X-ray absorption fine structure study of multinuclear copper(I) thiourea mixed ligand complexes

    Science.gov (United States)

    Gaur, Abhijeet; Shrivastava, B. D.; Srivastava, K.; Prasad, J.; Raghuwanshi, V. S.

    2013-07-01

    X-ray absorption fine structure spectra of five copper(I) thiourea complexes [Cu4(thu)6 (NO3)4 (H2O)4] (1), [Cu4(thu)9 (NO3)4 (H2O)4] (2), [Cu2(thu)6 (SO4) H2O] (3), [Cu2(thu)5 (SO4) (H2O)3] (4), and [Cu(thu)Cl 0.5H2O] (5) have been investigated. Complexes 1 and 3 are supposed to have one type of copper centers in trigonal planar and tetrahedral environment, respectively. Complexes 2 and 4 are supposed to have two types of copper centers, one center having trigonal planar geometry and another center having tetrahedral geometry. The aim of the present work is to show how extended X-ray absorption fine structure (EXAFS) spectra of these complexes, having different types of coordination environment, can be analyzed to yield the coordination geometry around one type of copper centers present in complexes 1 and 3, and two types of copper centers present in complexes 2 and 4. The crystal structure of complex 5 is unavailable due to inability of growing its single crystals, and hence the coordination geometry of this complex has been determined from EXAFS. The structural parameters determined from the EXAFS spectra have been reported and the coordination geometry has been depicted for the metal centers present in all the five complexes. Also, the chemical shifts have been used to determine the oxidation state of copper in these complexes. The X-ray absorption near edge spectra features have also been correlated with the coordination geometry. Also, the presence of both three and four coordinated Cu(I) centers in complexes 2 and 4 has been suggested from a comparison of the intensity of the feature at 8984 eV with those of 1 and 3. Further, in case of complex 5, the high intensity of peak A at 8986.5 eV is found to correspond to the presence of Cl coordinated to the copper center.

  3. Hexaniobate as nanoscale catalyst support for copper oxidase mimics based on metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bizeto, Marcos Augusto [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil); Alves, Wendel Andrade [Universidade Federal do ABC, SP (Brazil); Barbosa, Cesar Augusto Sales [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Bunge Fertilizantes; Ferreira, Ana Maria da Costa; Constantino, Vera Regina Leopoldo [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica

    2006-07-01

    Inorganic materials such as nanoporous zeolitic systems and layered structures have been considered special containers for chemical reactions, in which catalytically active species can show an energetic and/or spatial configuration that favors reactions of low activation energy. In this work, hexaniobate nanoscrolls were evaluated as a support for a metal complex that mimics copper oxidase enzymes. The cationic metal complex, 2-[2-(2-pyridyl)ethylimino-1-ethyl]pyridine-imidazole copper(II), [Cu(apip)imH]{sup 2}, was immobilized into hexaniobate scrolls by an ion exchange reaction. Chemical analysis, electronic and vibrational spectroscopies, thermogravimetric analysis and electron paramagnetic resonance (EPR) techniques were used to characterize the hexaniobatecopper complex system. High-resolution transmission electron microscopy of isolated hexaniobate particles containing the cationic complex showed the presence of scrolls with a wall thickness of about 4.5-7.0 nm and an external diameter of about 25-30 nm. X ray diffraction patterns confirmed the presence of the copper complex in the interlayer spaces of hexaniobate nanoscrolls. The reactivity of the copper complex supported on hexaniobate nanoscrolls was investigated for catechol oxidation in the presence of hydrogen peroxide. The formation of hydroxyl radicals (-OH) during the reaction was suggested by EPR data, which were obtained by monitoring the kinetics of DMPO/-OH adduct formation (DMPO is 5,5' dimethyl-1-pyrroline-N-oxide, used as spin trap). (author)

  4. Surface Structures Formed by a Copper(II Complex of Alkyl-Derivatized Indigo

    Directory of Open Access Journals (Sweden)

    Akinori Honda

    2016-10-01

    Full Text Available Assembled structures of dyes have great influence on their coloring function. For example, metal ions added in the dyeing process are known to prevent fading of color. Thus, we have investigated the influence of an addition of copper(II ion on the surface structure of alkyl-derivatized indigo. Scanning tunneling microscope (STM analysis revealed that the copper(II complexes of indigo formed orderly lamellar structures on a HOPG substrate. These lamellar structures of the complexes are found to be more stable than those of alkyl-derivatized indigos alone. Furthermore, 2D chirality was observed.

  5. Oxidation of aromatic alcohols on zeolite-encapsulated copper amino acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Teixeira Florencio, J.M. [Kaiserslautern Univ. (Germany). Dept. of Chemistry, Chemical Technology

    1998-12-31

    Copper complexes of the amino acids histidine, arginine and lysine have been introduced into the supercages of zeolite Y and, for the first time, into the large intracrystalline cavities of zeolites EMT and MCM-22. The resulting host/guest compounds are characterized by X-ray powder diffraction, UV/VIS-spectroscopy in the diffuse reflectance mode and by catalytic tests in the liquid-phase oxidation of aromatic alcohols (viz. benzyl alcohol, 2- and 3-methylbenzyl alcohol and 2,5-dimethylbenzyl alcohol) with tertiary-butylhydroperoxide as oxidant. It was observed that intracrystalline copper-amino acid complexes possess remarkable catalytic activity, yielding the corresponding aromatic aldehydes and acids. (orig.)

  6. A tri-copper(II) complex displaying DNA-cleaving properties and antiproliferative activity against cancer cells.

    Science.gov (United States)

    Suntharalingam, Kogularamanan; Hunt, Douglas J; Duarte, Alexandra A; White, Andrew J P; Mann, David J; Vilar, Ramon

    2012-11-19

    A new disubstituted terpyridine ligand and the corresponding tri-copper(II) complex have been prepared and characterised. The binding affinity and binding mode of this tri-copper complex (as well as the previously reported mono- and di-copper analogues) towards duplex DNA were determined by using UV/Vis spectroscopic titrations and fluorescent indicator displacement (FID) assays. These studies showed the three complexes to bind moderately (in the order of 10(4)  M(-1)) to duplex DNA (ct-DNA and a 26-mer sequence). Furthermore, the number of copper centres and the nature of the substituents were found to play a significant role in defining the binding mode (intercalative or groove binding). The nuclease potential of the three complexes was investigated by using circular plasmid DNA as a substrate and analysing the products by agarose-gel electrophoresis. The cleaving activity was found to be dependent on the number of copper centres present (cleaving potency was in the order: tri-copper>di-copper>mono-copper). Interestingly, the tri-copper complex was able to cleave DNA without the need of external co-reductants. As this complex displayed the most promising nuclease properties, cell-based studies were carried out to establish if there was a direct link between DNA cleavage and cellular toxicity. The tri-copper complex displayed high cytotoxicity against four cancer cell lines. Of particular interest was that it displayed high cytotoxicity against the cisplatin-resistant MOLT-4 leukaemia cell line. Cellular uptake studies showed that the tri-copper complex was able to enter the cell and more importantly localise in the nucleus. Immunoblotting analysis (used to monitor changes in protein levels related to the DNA damage response pathway) and DNA-flow cytometric studies suggested that this tri-copper(II) complex is able to induce cellular DNA damage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. and tetranuclear cluster complexes supported by phosphido bridges

    Indian Academy of Sciences (India)

    Administrator

    special interest to study the selectivity of formation in heterometallic examples, reaction patterns of multifunctionalized clusters, rigid and non-rigid behaviour of metal frameworks in ligand spheres, chirality transfer of rigid metal frameworks, development of homogeneous catalysts with cooperative effects, surface chemistry ...

  8. Series of dinuclear and tetranuclear lanthanide clusters encapsulated by salen-type and β-diketionate ligands: single-molecule magnet and fluorescence properties.

    Science.gov (United States)

    Sun, Wen-Bin; Han, Bing-Lu; Lin, Po-Heng; Li, Hong-Feng; Chen, Peng; Tian, Yong-Mei; Murugesu, Muralee; Yan, Peng-Fei

    2013-10-07

    Three dinuclear [Ln2H2OL(1)2(acac)2]·solvent (1, Ln = Gd, solvent = 2CH2Cl2; 2, Ln = Tb, no solvent; 3, Ln = Er, solvent = (C2H5)2O), and two tetranuclear lanthanide clusters [Ln4(μ3-OH)2L(2)2(acac)6]·2(solvent) (4, Ln = Tb, solvent = CH3OH; 5, Ln = Dy, solvent = CH3CN) were characterized in terms of structure, fluorescence and magnetism. The dinuclear lanthanide complexes were constructed by a rigid salen-type ligand H2L(1) = N,N'-bis(salicylidene)-o-phenylenediamine and β-diketonate (acac = acetylacetonate) ligands, while the tetranuclear clusters were formed from the flexible ligand H2L(2) = N,N'-bis(salicylidene)-1,2-ethanediamine. Crystal structure analysis indicates that the rigid ligand favors the double-decker sandwich structure (Ln2L(1)2), in which the two lanthanide ions have different coordination numbers and geometry, while the more flexible ligand (H2L(2)) leads to planar tetranuclear clusters. The relationship between their respective magnetic anisotropy and ligand-field geometries and their fluorescence properties was investigated. The Dy and Tb-containing clusters exhibit typical visible fluorescence properties, and single-molecule magnet behavior is seen in complex 5.

  9. Improving nuclease activity of copper(II)-terpyridine complex through solubilizing and charge effects of glycine.

    Science.gov (United States)

    Zhou, Wen; Wang, Xiaoyong; Hu, Ming; Guo, Zijian

    2013-04-01

    Copper complexes are potential metallonucleases that may find application in biotechnology and molecular biology. In this study, a ternary copper-terpyridine complex [Cu(ttpy)(Gly)(NO3)](NO3)·H2O (1) (ttpy=4'-p-tolyl-2,2':6,2″-terpyridine) is synthesized and characterized by X-ray crystallography and ESI-MS as an artificial nuclease. Glycine (Gly) is introduced into the complex to enhance the water-solubility and electrostatic affinity for the nucleic acid target. The interaction between complex 1 and DNA has been studied by spectroscopy and gel electrophoresis, using a structural analog [Cu(ttpy)(NO3)2] (2) as the reference. Complex 1 demonstrates an increased DNA binding ability and oxidative cleavage activity towards supercoiled pBR322 DNA as compared with complex 2. The enhanced water-solubility and positive charge of complex 1 may facilitate its access to DNA and formation of hydrogen bonds with the sugar-phosphate backbone. The results indicate that carefully positioned auxiliary groups in a copper complex can significantly affect the substrate binding or activation ability and consequently the nuclease efficiency of the complex. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Assessment of the isodesmic method in the calculation of standard reduction potential of copper complexes.

    Science.gov (United States)

    Chaparro, Diego; Alí-Torres, Jorge

    2017-09-21

    Molecular phenomena involving electron transfer and reduction/oxidation processes are of the utmost importance in chemistry. However, accurate computational calculations of standard reduction potentials (SRPs) for transition metal complexes are still challenging. For this reason, some computational strategies have been proposed in order to overcome the main limitations in SRP calculations for copper complexes. However, these strategies are limited to particular coordination spheres and do not represent a general methodology. In this work, we present standard reduction potential calculations for copper complexes in aqueous solution covering a wide range of coordination spheres. These calculations were performed using the M06-2X density functional, and by employing the direct and isodesmic approaches. Result analysis reveals that values obtained with the use of the isodesmic method are in better agreement with experimental values than those obtained from the direct method (mean unsigned error 0.39 V with the direct and 0.08 V with the isodesmic method). This approach provides values with errors comparable to the experimental uncertainty due to the proper cancellation of computational errors. These results strongly suggest the isodesmic approach as an adequate methodology for the calculation of SRPs for copper complexes with diverse coordination spheres. Graphical Abstract Comparison between direct and isodesmic methods in the calculation of standard reduction potentials for copper complexes using DFT methods.

  11. Copper(II) Chlorate Complexes - the Renaissance of a Forgotten and Misjudged Energetic Anion.

    Science.gov (United States)

    Wurzenberger, Maximilian H H; Szimhardt, Norbert; Stierstorfer, Jörg

    2018-02-16

    A convenient synthetic route toward new copper(II) chlorate complexes with potential use in modern advanced igni-tion or initiation systems is described. Obtained compounds were not only accurately characterized (XRD, IR, UV/Vis EA and DTA) but also investigated for their energetic character (sensitivities, initiation capability and laser ignition). The copper 4-aminotriazolyl chlorate complex showed excellent initiation of PETN, while also being thermally stable and safe to handle. Solid-state UV-Vis measurements were performed to get a possible insight toward the laser initia-tion mechanism. In contrast to expectations, the presented copper(II) chlorate energetic coordination compounds show manageable sensitivities that can be tamed or boosted by the appropriate choice of nitrogen-rich ligands.

  12. Human topoisomerase IB is a target of a thiosemicarbazone copper(II) complex.

    Science.gov (United States)

    Vutey, Venn; Castelli, Silvia; D'Annessa, Ilda; Sâmia, Luciana B P; Souza-Fagundes, Elaine M; Beraldo, Heloisa; Desideri, Alessandro

    2016-09-15

    The human topoisomerase IB inhibition and the antiproliferative activity of 3-(4-bromophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone HPyCT4BrPh alone and its copper(II) complex [Cu(PyCT4BrPh)Cl] was investigated. [Cu(PyCT4BrPh)Cl] inhibits both the DNA cleavage and religation step of the enzyme, whilst the ligand alone does not display any effect. In addition we show that coordination to copper(II) improves the cytotoxicity of HPyCT4BrPh against THP-1 leukemia and MCF-7 breast cancer cells. The data indicate that the copper(II) thiosemicarbazone complex may hit human topoisomerase IB and that metal coordination can be useful to improve cytotoxicity of this versatile class of compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Formation of complexes between functionalized chitosan membranes and copper: A study by angle resolved XPS

    Energy Technology Data Exchange (ETDEWEB)

    Jurado-López, Belén [Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain); Vieira, Rodrigo Silveira [Chemical Engineering Department, Universidade Federal do Ceará, UFC, 60455-760 Fortaleza, CE (Brazil); Rabelo, Rodrigo Balloni; Beppu, Marisa Masumi [School of Chemical Engineering, University of Campinas, UNICAMP, P.O. Box 6066, 13081-970 Campinas, SP (Brazil); Casado, Juan [Departamento de Química-Física, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain); Rodríguez-Castellón, Enrique, E-mail: castellon@uma.es [Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain)

    2017-01-01

    Chitosan is a biopolymer with potential applications in various fields. Recently, it has been used for heavy metals removal like copper, due to the presence of amino and hydroxyl groups in its structure. Chitosan membranes were crosslinked with epichlorohydrin and bisoxirano and functionalized with chelating agents, such as iminodiacetic acid, aspartic acid and tris-(2-amino-ethyl) polyamine. These membranes were used for copper adsorption and the formed complexes were characterized. Thermal and crystalline properties of chitosan membranes were studied by TG-DCS and X-ray diffraction. Raman, XPS and FT-IR data confirmed that copper is linked to the modified chitosan membranes by the amino groups. The oxidation state of copper-chitosan membranes were also studied by angle resolved XPS, and by UV–Vis diffuse reflectance spectroscopy. - Highlights: • Chitosan membranes were crosslinked with epichlorohydrin and bisoxirano and functionalized with chelating agents. • The chelating agent were iminodiacetic acid, aspartic acid and tris-(2-amino-ethyl) polyamine. • The functionalized membranes were used for copper adsorption and studied by ARXPS, Raman, TG-DCS, FT-IR and XRD. • Spectroscopic data confirmed that copper is linked to the modified chitosan membranes by the amino groups.

  14. Template Syntheses, Crystal Structures and Supramolecular Assembly of Hexaaza Macrocyclic Copper(II) Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taehyung; Kim, Ju Chang [Pukyong National Univ., Busan (Korea, Republic of); Lough, Alan J. [Univ. of Toronto, Toronto (Canada)

    2013-06-15

    Two new hexaaza macrocyclic copper(II) complexes were prepared by a template method and structurally characterized. In the solid state, they were self-assembled by intermolecular interactions to form the corresponding supramolecules 1 and 2, respectively. In the structure of 1, the copper(II) macrocycles are bridged by a tp ligand to form a macrocyclic copper(II) dimer. The dimer extends its structure by intermolecular forces such as hydrogen bonds and C-H···π interactions, resulting in the formation of a double stranded 1D supramolecule. In 2, the basic structure is a monomeric copper(II) macrocycle with deprotonated imidazole pendants. An undulated 1D hydrogen bonded array is achieved through hydrogen bonds between imidazole pendants and secondary amines, where the imidazole pendants act as a hydrogen bond acceptor. The 1D hydrogen bonded supramolecular chain is supported by C-H···π interactions between the methyl groups of acetonitrile ligands and imidazole pendants of the copper(II) macrocycles. In both complexes, the introduction of imidazoles to the macrocycle as a pendant plays an important role for the formation of supramolecules, where they act as intermolecular hydrogen bond donors and/or acceptors, C-H···π and π-π interactions.

  15. Fabrication and characterization of copper(II)-chitosan complexes as antibiotic-free antibacterial biomaterial.

    Science.gov (United States)

    Gritsch, Lukas; Lovell, Christopher; Goldmann, Wolfgang H; Boccaccini, Aldo R

    2018-01-01

    We produced and characterized copper(II)-chitosan complexes fabricated via in-situ precipitation as antibiotic-free antibacterial biomaterials. Copper was bound to chitosan from a dilute acetic acid solution of chitosan and copper(II) chloride exploiting the ability of the polysaccharide to chelate metal ions. The influence of copper(II) ions on the morphology, structure and hydrophobicity of the complexes was evaluated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and static contact-angle measurements. To assess the biological response to the materials, cell viability and antibacterial assays were performed using mouse embryonic fibroblasts and both Gram-positive and -negative bacteria. Combined analysis of cell and bacterial studies identified a threshold concentration at which the material shows outstanding antibacterial properties without significantly affecting fibroblast viability. This key outcome sets copper(II)- chitosan as a promising biomaterial and encourages further investigation on similar systems toward the development of new antibiotic-free antibacterial technologies. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. A novel dinuclear schiff base copper complex as an efficient and ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 7. A novel dinuclear schiff base copper complex as an efficient and cost effective catalyst for oxidation of alcohol: Synthesis, crystal structure and theoretical studies. Atena Naeimi Samira Saeednia Mehdi Yoosefian Hadi Amiri Rudbari Viviana Mollica Nardo.

  17. Copper (II) nickel (II), cobalt (II) and oxovanadium (IV) complexes of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 112; Issue 3. Copper(II) nickel(II), cobalt(II) and oxovanadium(IV) complexes of substituted ∙ - ... Author Affiliations. S Sevagapandian1 K Nehru1 P R Athappan1. Department of Inorganic Chemistry, Madurai Kamaraj University, Madurai 625 021, India ...

  18. Theoretical study, and infrared and Raman spectra of copper(II) chelated complex with dibenzoylmethane

    DEFF Research Database (Denmark)

    Nekoei, A.-R.; Vakili, M.; Hakimi-Tabar, M.

    2014-01-01

    There are some discrepancies in both the vibrational assignments and in the metal-ligand (M-L) bond strengths predicted in the previous studies on the copper (II) chelated complex of dibenzoylmethane, Cu(dbm)2. Also, there is a lack of theoretical structure, Raman spectrum and full vibrational as...

  19. Copper(II) complex as a precursor for formation of cyano-bridged ...

    Indian Academy of Sciences (India)

    chemsci

    Copper(II) complex as a precursor for formation of cyano-bridged pentanuclear Fe. III. -Cu. II bimetallic assembly: Synthesis, characterization, crystal structure and antibacterial ... Single-crystal X-ray analysis indicated that 2 crystallized in the monoclinic system with ..... maximum absorption band at 431nm was assigned to.

  20. Copper (II) complex as a precursor for formation of cyano-bridged ...

    Indian Academy of Sciences (India)

    Copper(II) complex as a precursor for formation of cyano-bridged pentanuclear FeIII-CuII bimetallic assembly: Synthesis, characterization, crystal structure and ... ATCC 27853 strains were studied and compared with standard drugs, which showed moderate antibacterial activity compared with Penicillin and Gentamicin.

  1. SYNTHESIS OF METAL-ORGANIC (COMPLEXES COMPOUNDS COPPER(II-IMIDAZOLE FOR ANTIVIRAL HIV CANDIDATE

    Directory of Open Access Journals (Sweden)

    Teguh Hari Sucipto

    2016-01-01

    Full Text Available The human immunodeficiency virus (HIV is viruses known as rotaviruses. Potential target for therapeutic is reverse transcriptase (RT, possesses an RNA dependent DNA polymerase, DNA-dependent DNA polymerase and ribonuclease H fuctions. Imidazoles have high anti-HIV inhibitory activity, some derivates of imidazole reported drugs. 8-chloro-2,3-dihydroimidazole[1,2-b] [1,4,2]benzodithiazine-5,5-dioxides and 9-chloro-2,3,4-trihydropyri-mido[1,2-b][1,4,2]benzodithi-azine-6,6-dioxides. This compounds succesfully identified anti-HIV activity. Copper is a bio-essential element and copper complexes have been extensively utilized in metal mediated DNA cleavage for the generation of activated oxygen species. It has been reported that teraaza macrocyclic copper coordination compounds have anti-HIV activities. Studies have shown that these macrocyclic complexes can react with DNA in different binding fashions and exhibit effective nuclease activities. Complex compounds are compounds in which there is an atom that acts as the central atom and trotter group of molecules that can be either neutral or charged ions. Application a metal-organic (complex compounds, especially copper metal and derivates of imidazole. So, in this study can explore new anti-HIV candidate.

  2. A New Copper (I) Complex Based on 4-amino-3, 5-bis (3-pyridyl)-1 ...

    Indian Academy of Sciences (India)

    A New Copper(I) Complex Based on 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole: Synthesis, Crystal Structure, Theoretical Study, Thermal Behavior and Luminescence. CHEN AI-HUA MENG SU-CI ZHOU KAI WANG CONG-CONG ZHAO WEI WANG AI-JIAN QIAN JUN. Regular Article Volume 129 Issue 2 February 2017 pp ...

  3. Synthetic, Crystallographic, and Computational Study of Copper(II) Complexes of Ethylenediaminetetracarboxylate Ligands

    NARCIS (Netherlands)

    Matovic, Zoran D.; Miletic, Vesna D.; Cendic, Marina; Meetsma, Auke; van Koningsbruggen, Petra J.; Deeth, Robert J.; Matović, Zoran D.; Miletić, Vesna D.; Ćendić, Marina

    2013-01-01

    Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H(4)eda3p and Rieddadp (H(4)eda3p = ethylenediamine-N-acetic-N,N',N'-tri-3-propionic acid; ateddadp = ethylenediamine-N,N'-diaceticN,N'-di-3-propionic acid) have been prepared. An octahedral trans(O-6) geometry (two

  4. (azo anils and oxalate ion) copper(ii) complexes

    African Journals Online (AJOL)

    B. S. Chandravanshi

    transition metal complexes compared to corresponding free ligands may be attributed to structural symmetry of transition metal. ... proved higher antibacterial activities when coordinated to central metal atom in compared to free ligand [5]. ... central metal atom led the complexes for numerous biomedicinal functions such as.

  5. (azo anils and oxalate ion) copper(ii) complexes

    African Journals Online (AJOL)

    B. S. Chandravanshi

    54890, Pakistan. 2Nano Science and Catalysis Division, National Centre for Physics, Islamabad-45320, Pakistan. (Received October ... Antibacterial activities of free ligands (azo anils and oxalate) and Cu(II) complexes were determined. Gram.

  6. Spectroscopic studies on some azo compounds and their cobalt, copper and nickel complexes

    Science.gov (United States)

    Masoud, Mamdouh. S.; Khalil, Ekram A.; Hindawy, Ahmed M.; Ali, Alaa E.; Mohamed, Eman F.

    2004-10-01

    Synthesis and characterization of [ o-carboxy phenylazo] moiety of barbituric acid, thiobarbituric acid, thiouracil, citrazinic acid, and disodium chromotropate and their complexes derived from cobalt (II), nickel (II), and copper (II) salts were done. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, NMR, UV-Vis, IR and ESR. The dissociation constants of the free azo ligands are evaluated by spectrophotometric methods.

  7. Copper Complexes Of Di-, Tri-, And Tetra-Peptides Containing Tryptophan, Histidine And Arginine

    OpenAIRE

    El Naggar, A. M. [احمد محمد النجار; El-Ghaffar, S. A. A.; Zaher, M. R.

    1983-01-01

    Fifty Seven copper complexes of di-, tri-. and tetra-peptides containing tryptophan, histidine and arginine are studied spectrophotometrically. The ^a, and colour of the complexes are dependent on the sequence of the amino acid in the dipeptide methyl esters of tryptophan and arginine; and independent on the sequence of dipeptides of histidine or in any of the tri- and tetra-peptides of histidine, arginine and tryptophan. The results achieved confirmed that the nitrogen atoms of the indole nu...

  8. The effect of pH and storage on copper speciation and bacterial growth in complex growth media

    DEFF Research Database (Denmark)

    Hasman, Henrik; Bjerrum, Morten J.; Christiansen, Lasse Engbo

    2009-01-01

    In this paper we examine how the bacterial growth is influenced by the availability of copper ions in complex Mueller Hinton growth media. The data shows that the free copper concentration is seven to eight orders of magnitude lower the total copper concentration and that there seems to be a better...... correlation between the free copper concentration and bacterial growth, than for the total copper concentration and growth. Furthermore, it is shown that the initial pH influences the amount of free copper ions in the media and that this has a direct effect on the ability of bacterial cultures to grow....... However, there still remains an effect of pH on bacterial growth which cannot be attributed to the influence of the Cu2+ concentration alone. The study also shows that the sterilization treatment can have some effect on the availability of copper ions in the media over time. Freshly autoclaved and sterile...

  9. Ergothioneine prevents copper-induced oxidative damage to DNA and protein by forming a redox-inactive ergothioneine-copper complex.

    Science.gov (United States)

    Zhu, Ben-Zhan; Mao, Li; Fan, Rui-Mei; Zhu, Jun-Ge; Zhang, Ying-Nan; Wang, Jing; Kalyanaraman, Balaraman; Frei, Balz

    2011-01-14

    Ergothioneine (2-mercaptohistidine trimethylbetaine) is a naturally occurring amino acid analogue found in up to millimolar concentrations in several tissues and biological fluids. However, the biological functions of ergothioneine remain incompletely understood. In this study, we investigated the role of ergothioneine in copper-induced oxidative damage to DNA and protein, using two copper-containing systems: Cu(II) with ascorbate and Cu(II) with H(2)O(2) [0.1 mM Cu(II), 1 mM ascorbate, and 1 mM H(2)O(2)]. Oxidative damage to DNA and bovine serum albumin was measured as strand breakage and protein carbonyl formation, respectively. Ergothioneine (0.1-1.0 mM) provided strong, dose-dependent protection against oxidation of DNA and protein in both copper-containing systems. In contrast, only limited protection was observed with the purported hydroxyl radical scavengers, dimethyl sulfoxide and mannitol, even at concentrations as high as 100 mM. Ergothioneine also significantly inhibited copper-catalyzed oxidation of ascorbate and competed effectively with histidine and 1,10-phenanthroline for binding of cuprous copper, but not cupric copper, as demonstrated by UV-visible and low-temperature electron spin resonance techniques. We conclude that ergothioneine is a potent, natural sulfur-containing antioxidant that prevents copper-dependent oxidative damage to biological macromolecules by forming a redox-inactive ergothioneine-copper complex.

  10. DNA binding and cleavage studies of copper(II) complexes with 2'-deoxyadenosine modified histidine moiety.

    Science.gov (United States)

    Borowska, Justyna; Sierant, Malgorzata; Sochacka, Elzbieta; Sanna, Daniele; Lodyga-Chruscinska, Elzbieta

    2015-09-01

    This work is focused on the study of DNA binding and cleavage properties of 2'-deoxyadenosines modified with ester/amide of histidine (his(6)dA ester, his(6)dA amide) and their copper(II) complexes. To determine the coordination mode of the complex species potentiometric and spectroscopic (UV-visible, CD, EPR) studies have been performed. The analysis of electronic absorption and fluorescence spectra has been used to find the nature of the interactions between the compounds and calf thymus DNA (CT-DNA). There is significant influence of the -NH2 and -OCH3 groups on binding of the ligands or the complexes to DNA. Only amide derivative and its complex reveal intercalative ability. In the case of his(6)dA ester and Cu(II)-his(6)dA ester the main interactions can be groove binding. DNA cleavage activities of the compounds have been examined by gel electrophoresis. The copper complexes have promoted the cleavage of plasmid DNA, but none of the ligands exhibited any chemical nuclease activity. The application of different scavengers of reactive oxygen species provided a conclusion that DNA cleavage caused by copper complexes might occur via hydrolytic pathway.

  11. Fabrication of copper-selective PVC membrane electrode based on newly synthesized copper complex of Schiff base as carrier

    Directory of Open Access Journals (Sweden)

    Sulekh Chandra

    2016-09-01

    Full Text Available The newly synthesized copper(II complex of Schiff base p-hydroxyacetophenone semicarbazone was explored as neutral ionophore for the fabrication of poly(vinylchloride (PVC based membrane electrode selective to Cu(II ions. The electrode shows a Nernstian slope of 29.8 ± 0.3 mV/decade with improved linear range of 1.8 × 10−7 to 1.0 × 10−1 M, comparatively lower detection limit 5.7 × 10−8 M between pH range of 2.0–8.0, giving a relatively fast response within 5s and can be used for at least 16 weeks without any divergence in potential. The selectivity coefficient was calculated using the fixed interference method (FIM. The electrode can also be used in partially non-aqueous media having up to 25% (v/v methanol, ethanol or acetone content with no significant change in the value of slope or working concentration range. It was successfully applied for the direct determination of copper content in water and tea samples with satisfactory results. The electrode has been used in the potentiometric titration of Cu2+ with EDTA.

  12. [Development of a therapeutic agent for Menkes disease: solubilization of a copper-disulfiram complex].

    Science.gov (United States)

    Hoshi, Yujiro; Tani, Norihiko; Tabata, Hidetsugu; Wakamatsu, Shintaro; Munakata, Mitsutoshi; Maruyama, Kazuo; Kodama, Hiroko; Oshitari, Tetsuta; Natsugari, Hideaki; Takahashi, Hideyo

    2015-01-01

    Menkes disease (MD) is a neurodegenerative disorder characterized by copper deficiency. It is caused by defective intestinal absorption of copper resulting from a deficiency of a copper-transporting ATPase, ATP7A. We investigated the effects of combination therapy with copper and disulfiram, a known lipophilic chelator. We synthesized a copper-disulfiram complex (Cu-DSF) and determined its crystal structure by X-ray crystallographic analysis. Unfortunately, Cu-DSF was not orally bioavailable due to its lipophilicity. We therefore planned to use cyclodextrin as a solubilizing agent to increase the water solubility of Cu-DSF. After comparisons of the effects of cyclodextrins (α, β, γ), it was found that addition of β-cyclodextrin (β-CyD) increased the solubility of Cu-DSF. Moreover, the modified β-CyD, hydroxypropyl-β-cyclodextrin, was yet more effective as a solubilizing agent. For the development of a convenient method to determine the concentration of Cu-DSF included by β-cyclodextrins, a standard curve based on UV-visible(VIS) absorption was derived.

  13. Structure determination of picolinato copper(II)-amine complexes

    Science.gov (United States)

    Mautner, Franz A.; Massoud, Salah S.

    2007-12-01

    Two series of Cu(II)-picolinato complexes of 1:1 and 3:2 Cu(II)-amine/picolinate namely [Cu(L 1)(pic)]ClO 4 and [Cu 3(L 2) 3(pic) 2(H 2O)](ClO 4) 4· xH 2O or [Cu 3(dpt) 3(pic) 2](ClO 4) 4, where pic = picolinate anion, L 1 = dien (diethylenetriamine), Et 2dien ( N, N-diethyldiethylenetriamine), Medpt (3,3'-diamino- N-methyldipropylamine), L 2 = pmedien ( N, N, N', N″, N″-pentamethyl-diethylenetriamine), TPA (tris(2-pyridylmethyl)amine), and dpt = dipropylenetriamine were synthesized and structurally characterized by electronic and IR spectroscopy. Single crystal X-ray diffraction analysis of the complex [Cu(dien)(pic)]ClO 4 ( 1) reveals its monomeric nature whereas for [Cu 3(pmedien) 3(pic) 2(H 2O)](ClO 4) 4·2H 2O ( 4), it was shown that the complex consists of two subunits of the mononuclear [Cu(pmedien)(pic)] + and the dinuclear [Cu 2(pmedien) 2(pic)(H 2O)] 3+ cations with the perchlorate as counter ions and lattice water molecules. In the mononuclear complexes of 1 and 4 the picolinato anions act as N, O-chelating ligands, whereas N, O, O'-picolinato bridges are observed in the dinuclear [Cu 2(pmedien) 2(pic)(H 2O)] 3+ cations of 4. The aqueous visible spectra of the complexes 1- 6 are consistent with five-coordinate Cu(II) species where distorted square pyramidal geometry (SP) was assigned for complexes 2- 5, trigonal bipyramidal geometry (TBP) for 6 and an intermediate geometry between SP and TBP for 1.

  14. Fluorescent copper(II complexes: The electron transfer mechanism, interaction with bovine serum albumin (BSA and antibacterial activity

    Directory of Open Access Journals (Sweden)

    Madhumita Hazra

    2017-01-01

    Full Text Available Dinuclear copper(II complexes with formula [Cu2(L2(N32] (1 and [Cu2(L2(NCS2] (2 HL = (1-[(3-methyl-pyridine-2-ylimino-methyl]-naphthalen-2-ol were synthesized by controlling the molar ratio of Cu(OAC2·6H2O, HL, sodium azide (1 and ammonium thiocyanate (2. The end on bridges appear exclusively in azide and thiocyanate to copper complexes. The electron transfer mechanism of copper(II complexes is examined by cyclic voltammetry indicating copper(II complexes are Cu(II/Cu(I couple. The interactions of copper(II complexes towards bovine serum albumin (BSA were examined with the help of absorption and fluorescence spectroscopic tools. We report a superficial solution-based route for the synthesis of micro crystals of copper complexes with BSA. The antibacterial activity of the Schiff base and its copper complexes were investigated by the agar disc diffusion method against some species of pathogenic bacteria (Escherichia coli, Vibrio cholerae, Streptococcus pneumonia and Bacillus cereus. It has been observed that the antibacterial activity of all complexes is higher than the ligand.

  15. Effects of Copper Exchange Levels on Complexation of Ammonia in ...

    African Journals Online (AJOL)

    NJD

    complex is [Cu(Ozeo)2(NH3)2]2+ and it is strongly bound to the zeolite framework walls at single four ring sites (site III). Above five ... electron paramagnetic resonance (EPR), with the intention completely to elucidate the siting-coordination of copper– ammonia interactions in the zeolite matrix. The combined EPR,. DRS and ...

  16. Synthesis and structure of copper (II) complexes: Potential cyanide ...

    Indian Academy of Sciences (India)

    ... ofbenzyl alcohols using the newly synthesized complexes as catalyst has been studied. Photoluminescence propertiesof [ ( L a 2 ) 2 C u ] and [ ( L b 2 ) 2 C u ] were exploited for selective cyanide recognition. The $[(L_{b})_{2}Cu], complexesdisplayed antibacterial activity toward gram positive and gram negative bacteria ...

  17. Antiviral Activity of Copper Complexes of Isoniazid against RNA ...

    Indian Academy of Sciences (India)

    George H Kitzman Professor of Genetics, Chief, Division of Cellular and Molecular Therapy, Departments of Pediatrics, Molecular Genetics & Microbiology, Powell Gene Therapy Center, Assistant Director, General Clinical Research Center, Cancer and Genetics Research Complex, 1376 Mowry Road, Room 492-A, ...

  18. Photocytotoxic ternary copper(II) complexes of histamine Schiff base ...

    Indian Academy of Sciences (India)

    ARC

    color codes: C black, N green, O blue, Cu red, and H white]. Figure S8. The spectral traces showing the decrease of emission intensity of ct-DNA bound ethidium bromide on increasing complex 2concentration in 5 mM Tris-HCl buffer medium.

  19. Photocytotoxic ternary copper (II) complexes of histamine Schiff ...

    Indian Academy of Sciences (India)

    pyramidal geometry. Complex 2 intercalatively binds to calf-thymus (ct) DNA with a binding constant (b) of ∼105 M−1. It exhibited moderate chemical nuclease activity but excellent DNA photocleavage activity in red light of 647 nm forming ...

  20. Salicylaldimine Copper(II) complex catalyst: Pioneer for ring ...

    Indian Academy of Sciences (India)

    in surgery as orthopedic applications, tissue engineer- ing and biodegradable internal fixation devices.8,9. The preventive use in biomedical application is .... showed a weight loss of 37.0 wt%, which indicates that. Cu(MBED) complex was more stable42 in compari- son to ligand (figure 2). In addition to thermal analy-.

  1. Synthesis of copper and nickel complexes using compartmental ...

    Indian Academy of Sciences (India)

    Administrator

    Department of Inorganic Chemistry, University of Madras, Guindy Campus,. Chennai 600 025, India. The search for several synthetic routes leading to mononuclear or polynuclear complexes have been stimulated by the potential relevance of these compounds in bioinorganic chemistry. One of them consists of the synthesis ...

  2. Inhibition of the catecholase activity of biomimetic dinuclear copper complexes by kojic acid.

    Science.gov (United States)

    Battaini, G; Monzani, E; Casella, L; Santagostini, L; Pagliarin, R

    2000-04-01

    The inhibition of the catechol oxidase activity exhibited by three dinuclear copper(II) complexes, derived from different diaminotetrabenzimidazole ligands, by kojic acid [5-hydroxy-2-(hydroxymethyl)-gamma-pyrone] has been studied. The catalytic mechanism of the catecholase reaction proceeds in two steps and for both of these inhibition by kojic acid is of competitive type. The inhibitor binds strongly to the dicopper(II) complex in the first step and to the dicopper-dioxygen adduct in the second step, preventing in both cases the binding of the catechol substrate. Binding studies of kojic acid to the dinuclear copper(II) complexes and a series of mononuclear analogs, carried out spectrophotometrically and by NMR, enable us to propose that the inhibitor acts as a bridging ligand between the metal centers in the dicopper(II) catalysts.

  3. Copper(I)/NO(g) Reductive Coupling Producing a trans-Hyponitrite Bridged Dicopper(II) Complex: Redox Reversal Giving Copper(I)/NO(g) Disproportionation.

    Science.gov (United States)

    Wijeratne, Gayan B; Hematian, Shabnam; Siegler, Maxime A; Karlin, Kenneth D

    2017-09-27

    A copper complex, [Cu(I)(tmpa)(MeCN)](+), effectively reductively couples NO(g) at RT in methanol (MeOH), giving a structurally characterized hyponitrito-dicopper(II) adduct. Hydrogen-bonding from MeOH is critical for the hyponitrite complex formation and stabilization. This complex exhibits the reverse redox process in aprotic solvents, giving Cu(I) + NO(g), leading to Cu(I)-mediated NO(g)-disproportionation. The relationship of this chemistry to biological iron and/or copper mediated NO(g) reductive coupling to give N2O(g) is discussed.

  4. Study of Copper and Purine-Copper Complexes on Modified Carbon Electrodes by Cyclic and Elimination Voltammetry

    Science.gov (United States)

    Trnkova, Libuse; Zerzankova, Lenka; Dycka, Filip; Mikelova, Radka; Jelen, Frantisek

    2008-01-01

    Using a paraffin impregnated graphite electrode (PIGE) and mercury-modified pyrolytic graphite electrode with basal orientation (Hg-PGEb) copper(II) and Cu(II)-DNA purine base solutions have been studied by cyclic (CV) and linear sweep voltammetry (LSV) in connection with elimination voltammetry with linear scan (EVLS). In chloride and bromide solutions (pH 6), the redox process of Cu(II) proceeded on PIGE with two cathodic and two anodic potentially separated signals. According to the elimination function E4, the first cathodic peak corresponds to the reduction Cu(II) + e- → Cu(I) with the possibility of fast disproportionation 2Cu(I) → Cu(II)+ Cu(0). The E4 of the second cathodic peak signalized an electrode process controlled by a surface reaction. The electrode system of Cu(II) on Hg-PGEb in borate buffer (pH 9.2) was characterized by one cathodic and one anodic peak. Anodic stripping voltammetry (ASV) on PIGE and cathodic stripping voltammetry (CSV) on Hg-PGEb were carried out at potentials where the reduction of copper ions took place and Cu(I)-purine complexes were formed. By using ASV and CSV in combination with EVLS, the sensitivity of Cu(I)-purine complex detection was enhanced relative to either ASV or CSV alone, resulting in higher peak currents of more than one order of magnitude. The statistical treatment of CE data was used to determine the reproducibility of measurements. Our results show that EVLS in connection with the stripping procedure is useful for both qualitative and quantitative microanalysis of purine derivatives and can also reveal details of studied electrode processes. PMID:27879715

  5. Nucleophilic reactivity of a copper(II)-superoxide complex.

    Science.gov (United States)

    Pirovano, Paolo; Magherusan, Adriana M; McGlynn, Ciara; Ure, Andrew; Lynes, Amy; McDonald, Aidan R

    2014-06-02

    Metal-bound superoxide intermediates are often implicated as electrophilic oxidants in dioxygen-activating metalloenzymes. In the nonheme iron α-ketoglutarate dependent oxygenases and pterin-dependent hydroxylases, however, Fe(III)-superoxide intermediates are postulated to react by nucleophilic attack on electrophilic carbon atoms. By reacting a Cu(II)-superoxide complex (1) with acyl chloride substrates, we have found that a metal-superoxide complex can be a very reactive nucleophile. Furthermore, 1 was found to be an efficient nucleophilic deformylating reagent, capable of Baeyer-Villiger oxidation of a number of aldehyde substrates. The observed nucleophilic chemistry represents a new domain for metal-superoxide reactivity. Our observations provide support for the postulated role of metal-superoxide intermediates in nonheme iron α-ketoglutarate dependent and pterin-dependent enzymes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Aliphatic C-H bond oxidation of toluene using copper peroxo complexes that are stable at room temperature.

    Science.gov (United States)

    Würtele, Christian; Sander, Ole; Lutz, Volker; Waitz, Thomas; Tuczek, Felix; Schindler, Siegfried

    2009-06-10

    Dinuclear copper peroxo complexes obtained from mononuclear copper(I) complexes showed extremely high stabilities under ambient conditions in the solid state and could be heated above 100 degrees C without decomposition. The increased stability could be explained with regard to their molecular structures. Furthermore, the four complexes investigated showed a high potential for aliphatic C-H bond oxidations: for example, technical-grade toluene was oxidized to benzaldehyde in yields of up to 20%.

  7. Computational simulations of copper complexes relevant to Alzheimer's disease

    Science.gov (United States)

    Alí-Torres, Jorge; Marechal, Jean-Didier; Mirats, Andrea; Rodríguez-Rodríguez, Cristina; Rodríguez-Santiago, Luis; Sodupe, Mariona

    2014-10-01

    Metal cations such as Cu2+ have been shown to induce amyloid aggregation and formation of reactive oxygen species. Elucidation of the structural features of Cu2+-Aβ is thus, essential to understand their role in the aggregation of Aβ, formation of ROS and to rationally design new chelators with potential therapeutic applications. Present contribution reviews our computational studies in this field. First, computational strategies used to determine three dimensional structures for Cu2+Aβ(1-16) and the redox properties of these complexes will be discussed and second, we will summarize our recent studies on Cu2+ chelators.

  8. Synthesis and spectral studies of copper complexes using a N-octylated bis benzimidazole diamide ligand

    Science.gov (United States)

    Mohapatra, Subash Chandra; Mathur, Pavan

    2011-02-01

    Monomeric Cu(II) and Cu(I) complexes bound to a tetradentate bis-benzimidazole diamide ligand N,N'-bis(N-octyl benzimidazolyl-2yl)(methyl)pentane diamide (O-GBGA) have been isolated and characterized. X-Band EPR spectra of the copper(II) complexes in CH 2Cl 2 were recorded in a frozen solution as solvent at liquid nitrogen temperature. Solution spectra typically indicate a d ground state ( g|| > g⊥ > 2.0023) and show less than four nuclear hyperfine lines with broadening of g⊥ line in some cases, thus indicating distorted tetragonal geometry. One of the copper(II) complexes shows a five line N-SHF structure (16 ± 1 G) implying the binding of imine nitrogen of the benzimidazole to copper ion. α2 ranges from 0.57-0.97 indicating considerable amount of covalent character in Cu-L bond. Anodic shifts in E1/2 values indicate the retention of anion in the coordination sphere of Cu(II), E1/2 values becoming anodic in the order C 6H 5COO - complexes was found to be lower than that of the ligand O-GBGA ( Φ = 0.029) and the relative fluorescence data reveals that fluorescence of such compounds could distinguish between small and large anions.

  9. Structural correlation of catecholase-like activities of oxy-bridged dinuclear copper(II) complexes.

    Science.gov (United States)

    Kao, C H; Wei, H H; Liu, Y H; Lee, G H; Wang, Y; Lee, C J

    2001-04-01

    Eight oxy-bridged dinuclear copper(II) complexes with catecholase-like sites, [Cu(L1)X]2 (HL1 = 1-diethylaminopropan-2-ol, X=N3- 1, NCO- 2, and NO2- 3), [Cu(L2)X]2 (HL2=N-ethylsalicylaldimine, X=NO3- 4, Cl- 5, N3- 6, NCS- 7), and [Cu(L3)]2(ClO4)2, 8 (HL3=N-(salicylidene)-N'-(2-pyridylaldene)propanediamine) have been prepared and characterized. The single crystal X-ray analysis show that the structures of complexes 6 and 8 are dimeric with two adjacent copper(II) atoms bridged by pairs of micro-oxy atoms from the L2 and L3 ligands. Magnetic susceptibility measurements in the temperature range 4-300 K indicate significant antiferromagnetic coupling for 4, 5 and 7 and ferromagnetic coupling for 6 between the copper(II) atoms. The catecholase activity of complexes for the oxidation of 3,5-di-tert-butylcatechol by O2 was studied and it was found that the complexes with the bond distance of Cu(II)...Cu(II) located at 2.9-3.0 A show higher catecholase activity.

  10. Efficient SN2 fluorination of primary and secondary alkyl bromides by copper(I) fluoride complexes

    KAUST Repository

    Liu, Yanpin

    2013-11-11

    Copper(I) fluoride complexes ligated by phenanthroline derivatives have been synthesized and structurally characterized by X-ray crystallography. These complexes adopt as either ionic or neutral forms in the solid state, depending on the steric bulkiness of the substituent groups on the phenanthroline ligands. These complexes react with primary and secondary alkyl bromides to produce the corresponding alkyl fluorides in modest to good yields. This new method is compatible with a variety of important functional groups such as ether, thioether, amide, nitrile, methoxyl, hydroxyl, ketone, ester, and heterocycle moieties. © 2013 American Chemical Society.

  11. Synthesis, Cytotoxic Activity, and DNA Binding Properties of Copper (II) Complexes with Hesperetin, Naringenin, and Apigenin

    OpenAIRE

    Tan, Mingxiong; Zhu, Jinchan; Pan, Yingming; Chen, Zhenfeng; Liang, Hong; Liu, Huagang; Wang, Hengshan

    2009-01-01

    Complexes of copper (II) with hesperetin, naringenin, and apigenin of general composition [CuL2(H2O)2]⋅nH2O (1–3) have been synthesized and characterized by elemental analysis, UV-Vis, FT-IR, ESI-MS, and TG-DTG thermal analysis. The free ligands and the metal complexes have been tested in vitro against human cancer cell lines hepatocellular carcinoma (HepG-2), gastric carcinomas (SGC-7901), and cervical carcinoma (HeLa). Complexes 1 and 3 were found to exhibit growth inhibition of SGC-79...

  12. Assignment of the Charge-Transfer Excited States of Bis(N-Heterocyclic) Complexes of Copper(I)

    Science.gov (United States)

    1989-03-21

    Excited States of Bis (N-Heterocyclic) Complexes of Copper ( I) 12 PERSONAL AUTHOR(S( W. L. Parker and G. A. Crosby 3a 7YPE OF REPORT i b ’!ME COVERED ~ aDATE...Assignment of the Charge-Transfer Excited States of Bis (N-Heterocyclic) Complexes of Copper (I) by W. L. Parker and G. A. Crosby Prepared for Publication in...IHmited. Assignment of the Charge-Transfer Excited States of Bis (N-Heterocycl ic) Complexes of Copper (I) W. L. Parker and G. A. Crosby* Chemical

  13. Physicochemical characterization of functionalized-nanostructured-titania as a carrier of copper complexes for cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    López, Tessy [Nanotechnology and Nanomedicine Laboratory, Metropolitan Autonomous University-Xochimilco, Calzada del Hueso 1100, Villa Quietud, Coyoacán, 04960 México D.F. (Mexico); Nanotechnology Laboratory, National Institute of Neurology and Neurosurgery “MVS”, Avenida Insurgentes Sur 3877, La Fama, Tlalpan, 14269 México D.F. (Mexico); Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St. Charles Avenue, New Orleans (United States); Ortiz, Emma, E-mail: emma170@hotmail.com [Nanotechnology Laboratory, National Institute of Neurology and Neurosurgery “MVS”, Avenida Insurgentes Sur 3877, La Fama, Tlalpan, 14269 México D.F. (Mexico); Guevara, Patricia [Neuroimmunology Laboratory, National Institute of Neurology and Neurosurgery “MVS”, Insurgentes Sur 3877, La Fama, Tlalpan, 14269 México D.F. (Mexico); Gómez, Esteban [Nanotechnology Laboratory, National Institute of Neurology and Neurosurgery “MVS”, Avenida Insurgentes Sur 3877, La Fama, Tlalpan, 14269 México D.F. (Mexico); Novaro, Octavio [Institute of Physics-UNAM, Circuito de la Investigación Científica Ciudad Universitaria, CP 04510 México D.F. (Mexico)

    2014-07-01

    In the present paper we report the preparation and characterization of functionalized-TiO{sub 2} (F-TiO{sub 2}) to obtain a biocompatible material to be used as carrier of alternative anticancer agents: copper acetate and copper acetylacetonate. The sol–gel procedure was used to prepare the fuctionalized titania material through hydrolysis and condensation of the titanium's butoxide. Sulfate, amine and phosphate ions served as functional groups which were anchored to the titania's surface. Mineral acids and gamma amine butyric acid were the precursors and they were added at the initial step of the synthesis. The copper complexes were loaded on titania and were also added to the reactor synthesis from the beginning. Infrared and ultraviolet–visible spectroscopies were the principal techniques used to the characterization of F-TiO{sub 2} and copper complexes loaded on titania materials. Transmission Electronic Microscopy (TEM) was used to complement the characterization's studies. The biocompatibility of F-TiO{sub 2} was evaluated by treating different cancer cell lines with increased concentration of this compound. The amine, the sulfate and the phosphate on the titania's surface, as well as the integral structures of the metal complexes on titania were well identified by infrared and ultraviolet–visible spectroscopies. The TEM photographs of Cu(acac){sub 2}/F-TiO{sub 2} and Cu(Oac){sub 2}/F-TiO{sub 2} materials showed the formation of nanoparticles, which have sizes ranging from 4 to 10 nm, with no morphology alterations in comparison with F-TiO{sub 2} nanoparticles, suggesting that the presence of low quantities of copper do not affect the structure of the nanoparticles. The Energy Dispersive Spectroscopy (EDS) confirms the presence of copper on the titania's nanoparticles. The biological results indicate that there is more than 90% cell survival, thus suggesting that F-TiO{sub 2} does not cause damage to the cells. Therefore

  14. Plasma-Induced Decomposition of Copper Complex Ink for the Formation of Highly Conductive Copper Tracks on Heat-Sensitive Substrates.

    Science.gov (United States)

    Farraj, Yousef; Smooha, Ariel; Kamyshny, Alexander; Magdassi, Shlomo

    2017-03-15

    The use of Cu-formate-2-amino-2-methyl-1-propanol ink and low-pressure plasma for the formation of highly conductive patterns on heat sensitive plastic substrates was studied. It was found that plasma results in decomposition of copper complex to form metallic copper without heating at high temperatures. Ink composition and plasma parameters (predrying conditions, plasma treatment duration, gas type, and flow rate) were optimized to obtain uniform conductive metallic films. The morphology and electrical characteristics of these films were evaluated. Exposing the printed copper metallo-organic decomposition (MOD) ink to 160 W plasma for 8 min yielded resistivity as low as 7.3 ± 0.2 μΩ cm, which corresponds to 23% bulk copper conductivity. These results demonstrate the applicability of MOD inks and plasma treatment to obtain highly conductive printed patterns on low-cost plastic substrates and 3D printed polymers.

  15. Dimeric Self-assembling via Hydrogen Bonding and Emissive Behavior of a New Copper (I Complex

    Directory of Open Access Journals (Sweden)

    Juciely M. dos Reis

    2017-04-01

    Full Text Available This work describes the synthesis, structural characterization and emissive behavior of a new copper (I complex based on 1-thiocarbamoyl-5-(4-methoxiphenyl-3-phenyl-4,5-dihydro-1H-pyrazole ligand. A dimeric self-assembling via hydrogen bonding was determined by analyzing the short contacts present in the solid-state structure by means of X-ray crystallography. The spectroscopic properties were determined using UV-Vis and fluorescence experiments and an interesting behavior as bluish luminescence was assigned mainly to the mixed (MLCT + IL electronic transitions of the Cu(Id10 ® (S=C–Nligand type. The complete characterization of the new copper (I complex also included elemental analyses and IR spectroscopy. DOI: http://dx.doi.org/10.17807/orbital.v9i1.952

  16. Infrared spectroscopy of copper-resveratrol complexes: A joint experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Chiavarino, B.; Crestoni, M. E.; Fornarini, S. [Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza - Universita di Roma, Piazzale A. Moro 5, 00185 Rome (Italy); Taioli, S. [Interdisciplinary Laboratory for Computational Science, FBK-CMM and University of Trento, Via Sommarive 18, 38123 Trento (Italy); Department of Physics, University of Trento, Via Sommarive 14, 38123 Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Chemistry, University of Bologna, Via F. Selmi 2, I-40126 Bologna (Italy); Mancini, I.; Tosi, P. [Department of Physics, University of Trento, Via Sommarive 14, 38123 Trento (Italy)

    2012-07-14

    Infrared multiple-photon dissociation spectroscopy has been used to record vibrational spectra of charged copper-resveratrol complexes in the 3500-3700 cm{sup -1} and 1100-1900 cm{sup -1} regions. Minimum energy structures have been determined by density functional theory calculations using plane waves and pseudopotentials. In particular, the copper(I)-resveratrol complex presents a tetra-coordinated metal bound with two carbon atoms of the alkenyl moiety and two closest carbons of the adjoining resorcinol ring. For these geometries vibrational spectra have been calculated by using linear response theory. The good agreement between experimental and calculated IR spectra for the selected species confirms the overall reliability of the proposed geometries.

  17. A five-coordinate copper complex with superoxide dismutase mimetic activity from Streptomyces antibioticus.

    Science.gov (United States)

    Schechinger, T; Hiller, W; Maichle, C; Strähle, J; Weser, U

    1988-01-01

    A Cu(II) complex of desferrithiocin from Streptomyces antibioticus was prepared and characterized. The first shell atoms, including one nitrogen and four oxygens, were arranged around the copper in a square-planar pyramide. Due to the axially Jahn-Teller-distorted Cu-O distance at 224.7 pm, a distinct Cu2Zn2superoxide dismutase mimetic activity was measured. The Cu-complex survived 600 microM bovine serum albumin and the thermodynamic stability (pK = 17.4) was not very different from that of Cu-EDTA. The electronic absorption properties, circular dichroism and electron paramagnetism were in accordance with those of the type-II copper species.

  18. Study of Copper and Purine-Copper Complexes on Modified Carbon Electrodes by Cyclic and Elimination Voltammetry

    Directory of Open Access Journals (Sweden)

    Frantisek Jelen

    2008-01-01

    Full Text Available Using a paraffin impregnated graphite electrode (PIGE and mercury-modifiedpyrolytic graphite electrode with basal orientation (Hg-PGEb copper(II and Cu(II-DNApurine base solutions have been studied by cyclic (CV and linear sweep voltammetry(LSV in connection with elimination voltammetry with linear scan (EVLS. In chlorideand bromide solutions (pH 6, the redox process of Cu(II proceeded on PIGE with twocathodic and two anodic potentially separated signals. According to the eliminationfunction E4, the first cathodic peak corresponds to the reduction Cu(II e- → Cu(I withthe possibility of fast disproportionation 2Cu(I → Cu(II Cu(0. The E4 of the secondcathodic peak signalized an electrode process controlled by a surface reaction. Theelectrode system of Cu(II on Hg-PGEb in borate buffer (pH 9.2 was characterized by onecathodic and one anodic peak. Anodic stripping voltammetry (ASV on PIGE and cathodicstripping voltammetry (CSV on Hg-PGEb were carried out at potentials where thereduction of copper ions took place and Cu(I-purine complexes were formed. By usingASV and CSV in combination with EVLS, the sensitivity of Cu(I-purine complexdetection was enhanced relative to either ASV or CSV alone, resulting in higher peakcurrents of more than one order of magnitude. The statistical treatment of CE data wasused to determine the reproducibility of measurements. Our results show that EVLS inconnection with the stripping procedure is useful for both qualitative and quantitativemicroanalysis of purine derivatives and can also reveal details of studied electrodeprocesses.

  19. Effect of glutamic acid on copper sorption onto kaolinite. Batch experiments and surface complexation modeling

    Energy Technology Data Exchange (ETDEWEB)

    Karimzadeh, Lotfallah; Barthen, Robert; Gruendig, Marion; Franke, Karsten; Lippmann-Pipke, Johanna [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactive Transport; Stockmann, Madlen [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

    2017-06-01

    In this work, we study the mobility behavior of Cu(II) under conditions related to an alternative, neutrophile biohydrometallurgical Cu(II) leaching approach. Sorption of copper onto kaolinite influenced by glutamic acid (Glu) was investigated in the presence of 0.01 M NaClO{sub 4} by means of binary and ternary batch adsorption measurements over a pH range of 4 to 9 and surface complexation modeling.

  20. Structural and spectroscopic characterization of copper(I) halogen complexes with omega-thiocaprolactam and triphenylphosphine

    NARCIS (Netherlands)

    Luic, M; KojicProdic, B; Herrema, J; Akrivos, PD; Karagiannidis, P

    1995-01-01

    A series of mixed ligand copper(I) halogeno complexes with omega-thiocaprolactam, (tclH) and triphenylphosphine (PPh(3)) of general formula Cu(tclH)(n)(PPh(3))(3-n)X where n = 1, 2 and X = CI, Pr, I has been studied. The crystal structure of Cu(tclH)(PPH3)(2)Br is reported and discussed with respect

  1. Copper(II Complexes of 4, 4- Diaminodiphenylsulphone: Synthesis, Characterization and Biological Studies

    Directory of Open Access Journals (Sweden)

    Adedibu C. Tella

    2009-01-01

    Full Text Available Five complexes of copper(II 4,4-diaminodiphenylsulphone have been synthesized. Copper salts of counter ion (sulphate, nitrate, chloride and different reaction media (solvents were used for the synthesis. The complexes varied in colour and composition. The compounds were characterized by conductivity, IR, UV, NMR and mass spectroscopies. The ligand coordinated to metal ion in a monodentate and bidentate manner. All the five complexes have tetrahedral configuration. The biological activities data showed that the complexes are more active against Esherichia coli, Klebbsiella pneumoniae and Staphylococcus aureus than the free ligand (4,4- diaminodiphenyl sulphone. Antimalaria activities of the complexes and the ligand were investigated using mice infected with Plasmodium berghei. All the complexes exhibited lower activity than the ligand and chloroquine. The effect of administration of the complexes on alkaline phosphatase activities of kidney, liver and serum of Albino rats were investigated. The serum ALP activity showed no significant change (P> 0.05, suggesting non-damaging effect on the plasma membrane of liver and kidney cells.

  2. Anti-proliferative effects of copper(II) complexes with hydroxyquinoline-thiosemicarbazone ligands.

    Science.gov (United States)

    Rogolino, Dominga; Cavazzoni, Andrea; Gatti, Anna; Tegoni, Matteo; Pelosi, Giorgio; Verdolino, Vincenzo; Fumarola, Claudia; Cretella, Daniele; Petronini, Pier Giorgio; Carcelli, Mauro

    2017-03-10

    The possibility to influence the physiological concentration of copper ions through the careful choice of ligands is emerging as a novel intriguing strategy in the treatment of pathologies such as cancer and Alzheimer. Thiosemicarbazones play an important role in this field, because they offer a wide variety of potential functionalizations and different kinds of coordination modes. Here we report the synthesis of some 8-hydroxyquinoline thiosemicarbazone ligands containing an ONN'S donor set and their Zn(II) and Cu(II) complexes. The metal complexes were characterized in solution and in the solid state and the X-ray structure of one of the copper(II) complex is reported. The Cu(II) complexes were characterized also by means of quantum mechanical calculations. The Cu(II) complexes displayed cytostatic activity in different cancer cell models. In particular, the most active Cu(II) complex significantly inhibited cell proliferation with an IC50 value lower than 1 μM; this effect was associated with a block of the cell cycle in the G2/M phase. This Cu(II) complex induced neither the production of reactive oxygen species (ROS) nor the accumulation of p53 protein, suggesting the lack of DNA damage. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Synthesis, Characterization, Molecular Modeling, and DNA Interaction Studies of Copper Complex Containing Food Additive Carmoisine Dye.

    Science.gov (United States)

    Shahabadi, Nahid; Akbari, Alireza; Jamshidbeigi, Mina; Khodarahmi, Reza

    2016-06-02

    A copper complex of carmoisine dye; [Cu(carmoisine)2(H2O)2]; was synthesized and characterized by using physico-chemical and spectroscopic methods. The binding of this complex with calf thymus (ct) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, and viscosity measurements. UV-vis results confirmed that the Cu complex interacted with DNA to form a ground-state complex and the observed binding constant (2× 10(4) M(-1)) is more in keeping with the groove bindings with DNA. Furthermore, the viscosity measurement result showed that the addition of complex causes no significant change on DNA viscosity and it indicated that the intercalation mode is ruled out. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the reaction. The results of circular dichroism (CD) suggested that the complex can change the conformation of DNA from B-like form toward A-like conformation. The cytotoxicity studies of the carmoisine dye and its copper complex indicated that both of them had anticancer effects on HT-29 (colon cancer) cell line and they may be new candidates for treatment of the colon cancer.

  4. Synthesis and thermal studies of tetraaza macrocylic ligand and its transition metal complexes. DNA binding affinity of copper complex.

    Science.gov (United States)

    Saif, M; Mashaly, Mahmoud M; Eid, Mohamed F; Fouad, R

    2011-09-01

    A Tetraaza Macrocylic Ligand (H2L) and its complexes, [Cd(H2L)(OH2)2](NO3)(2)·1/2OH2 (I), [Co(H2L)(OH2)](NO3)(2)·1/2OH2 (II), [Cu(H2L)(NO3)2]·3/2OH2 (III) and [Ni(H2L)(NO3)(OH2)]NO3·OH2 (IV), have been synthesized and characterized on the basis of elemental analysis, molar conductivity, 1H NMR, UV-vis, FT-IR and mass spectroscopy. All results confirm that the prepared compounds have 1:1 metal-to-ligand stoichiometry, octahedral configuration and the ligand behaves as a neutral tetradendate towards the metal ions. [CdL(OH2)2] (V), [CoL(OH2)2] (VI), [CuL(OH2)2] (VII) and [Ni(H2L)(NO3)2] (VIII) were synthesized pyrolytically in solid state from corresponding compounds (I-IV). Analytical results of complexes (V-VIII) show that the ligand behaves either as a neutral tetradendate or dianionic tetradentate ligand towards the metal ions. The binding of H2L and its copper complex (III) to DNA has been investigated by ultraviolet absorption spectroscopy. The experiments indicate that H2L and its copper complex (III) can bind to DNA through an intercalative mode. The H2L and its copper complex (III) exhibited anti-tumor activity against Ehrlich Acites Carcinoma (E.A.C) at the concentration of 100 μg/ml. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Antimalarial, antimicrobial, cytotoxic, DNA interaction and SOD like activities of tetrahedral copper(II) complexes

    Science.gov (United States)

    Mehta, Jugal V.; Gajera, Sanjay B.; Patel, Mohan N.

    2015-02-01

    The mononuclear copper(II) complexes with P, O-donor ligand and different fluoroquinolones have been synthesized and characterized by elemental analysis, electronic spectra, TGA, EPR, FT-IR and LC-MS spectroscopy. An antimicrobial efficiency of the complexes has been tested against five different microorganisms in terms of minimum inhibitory concentration (MIC) and displays very good antimicrobial activity. The binding strength and binding mode of the complexes with Herring Sperm DNA (HS DNA) have been investigated by absorption titration and viscosity measurement studies. The studies suggest the classical intercalative mode of DNA binding. Gel electrophoresis assay determines the ability of the complexes to cleave the supercoiled form of pUC19 DNA. Synthesized complexes have been tested for their SOD mimic activity using nonenzymatic NBT/NADH/PMS system and found to have good antioxidant activity. All the complexes show good cytotoxic and in vitro antimalarial activities.

  6. Bis(dipyridophenazine)copper(II) complex as major groove directing synthetic hydrolase.

    Science.gov (United States)

    Gupta, Tarkeshwar; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

    2004-06-21

    The copper(II) complex [Cu(dppz)(2)Cl]Cl () has been prepared, structurally characterized and its DNA binding and cleavage properties studied (dppz, dipyridophenazine). Crystal structure of 1xdppzxH(2)O shows the presence of the monocationic copper(II) complex containing two dppz ligands and one chloride in the five coordinate structure. While one bidentate chelating dppz ligand occupies the basal plane, the other dppz ligand shows an axial/equatorial mode of bonding. The chloride ligand binds at the basal plane. The complex crystallizes with dppz and water as lattice molecules. The dppz moieties in the metal-bound and free forms are involved in pi-pi stacking interactions. The one-electron paramagnetic complex shows a visible spectral d-d band at 707 nm in DMF and displays quasireversible cyclic voltammetric response for the Cu(II)/Cu(I) couple near 0.1 V vs. SCE in DMF-0.1 M TBAP. The complex which is an avid binder to calf thymus DNA giving a binding constant (K(b)) value of 2.0 x 10(4) M(-1) in DMF-Tris buffer, cleaves supercoiled pUC19 DNA in an oxidative manner in the presence of mercaptopropionic acid (MPA) as a reducing agent or on photo irradiation at 312 nm. Control experiments show major groove binding and DNA cleavage via the formation of hydroxyl radical in the presence of MPA and by singlet oxygen in the photocleavage reaction. The complex exhibits significant hydrolytic cleavage of DNA in the dark in the absence of any additives at a rate of approximately 3.0 h(-1). The hydrolytic nature of the DNA cleavage is evidenced from the T4 ligase experiments converting the nicked circular form to its original supercoiled form quantitatively. Complex presents a rare example of copper-based major groove directing efficient synthetic hydrolase.

  7. Immobilized copper(II) macrocyclic complex on MWCNTs with antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Tarlani, Aliakbar, E-mail: Tarlani@ccerci.ac.ir [Inorganic Nanostructures and Catalysts Research Lab., Chemistry & Chemical Engineering Research Center of Iran, Pajoohesh Blvd., km 17, Karaj Hwy, Tehran 14968-13151 (Iran, Islamic Republic of); Narimani, Khashayar [Inorganic Nanostructures and Catalysts Research Lab., Chemistry & Chemical Engineering Research Center of Iran, Pajoohesh Blvd., km 17, Karaj Hwy, Tehran 14968-13151 (Iran, Islamic Republic of); Mohammadipanah, Fatemeh; Hamedi, Javad [Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran 14155-6455 (Iran, Islamic Republic of); University of Tehran Biocompound Collection (UTBC), Microbial Technology and Products Research Center, University of Tehran, Tehran (Iran, Islamic Republic of); Tahermansouri, Hasan [Department of Chemistry, Ayatollah Amoli Branch, Islamic Azad University, Amol (Iran, Islamic Republic of); Amini, Mostafa M. [Department of Chemistry, Shahid Behshti University, 1983963113, Tehran (Iran, Islamic Republic of)

    2015-06-30

    Graphical abstract: In an antibacterial test, grafted copper(II) macrocyclic complex on the surface of MWCNT showed higher antibacterial activity against Bacillus subtilis compared to the individual MWCNT-COOH and the complex. - Highlights: • Copper(II) tetraaza macrocyclic complex covalently bonded to modified MWCNT. • Grafting of the complex carried out via an interaction between −C(=O)Cl group and NH of the ligand. • The samples were subjected in an antibacterial assessment to compare their activity. • Immobilized complex showed higher antibacterial activity against Bacillus subtilis ATCC 6633 compared to separately MWCNT-C(C=O)-OH and CuTAM. - Abstract: In a new approach, a copper(II) tetraaza macrocyclic complex (CuTAM) was covalently bonded on modified multi-walled carbon nanotubes (MWCNTs). To achieve this purpose, MWCNTs were converted to MWCNT-COCl and then reacted to NH groups of TAM ligand. The prepared material was characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), and FESEM (field emission scanning electron microscopy). FT-IR and TGA demonstrated the presence of the organic moieties, and XRD proved that the structure of MWCNTs remained intact during the three modification steps. An increase in the I{sub D}/I{sub G} ratio in Raman spectra confirmed the surface modifications. Finally, the samples were subjected to an antibacterial assessment to compare their biological activity. The antibacterial test showed that the grafted complex on the surface of the nanotube (MWCNT-CO-CuTAM) has higher antibacterial activity against Bacillus subtilis ATCC 6633 than the MWCNT-COOH and CuTAM with 1000 and 2000 μg/mL.

  8. Microstructure and mechanical properties of ultrafine grained complex copper alloy fabricated by accumulative roll-bonding process.

    Science.gov (United States)

    Lee, Seong-Hee; Lim, Cha-Yong

    2014-10-01

    Accumulative roll-bonding (ARB) process using dissimilar copper alloys was performed up to six cycles (-an equivalent strain of 4.8) at ambient temperature without lubricant for fabrication of a new complex copper alloy. The dissimilar copper alloy sheets of oxygen free copper (OFC) and dioxide low-phosphorous copper (DLPC) with thickness of 1 mm were degreased and wire-brushed for the ARB process. The sheets were then stacked together and rolled by 50% reduction so that the thickness became 1 mm again. The sheet was then cut to the two pieces of same length and the same procedure was repeated up to six cycles. A new sound complex copper alloy sheet in which OFC and DLPC are combined each other was successfully fabricated by the ARB process. The tensile strength of the copper alloy increased with increasing the number of ARB cycles, reached 492 MPa after six cycles, which is about three times of the initial material. The average grain size was 12.6 μm after the 1st cycle, but it became 1.5 μm after six cycles. Microstructures and mechanical properties of the complex copper alloy fabricated by the ARB were investigated in detail.

  9. Magnetism of a novel tetranuclear nickel(II) cluster in strong magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Kataev, V [Leibniz-Institute for Solid State and Materials Research IFW Dresden, PO Box 270116, 01171 Dresden (Germany); Golze, C [Leibniz-Institute for Solid State and Materials Research IFW Dresden, PO Box 270116, 01171 Dresden (Germany); Alfonsov, A [Kazan Physical Technical Institute, Russian Academy of Sciences, 420029 Kazan (Russian Federation); Klingeler, R [Leibniz-Institute for Solid State and Materials Research IFW Dresden, PO Box 270116, 01171 Dresden (Germany); Buechner, B [Leibniz-Institute for Solid State and Materials Research IFW Dresden, PO Box 270116, 01171 Dresden (Germany); Goiran, M [Laboratoire National des Champs Magnetiques Pulses, 31432 Toulouse Cedex 04 (France); Broto, J-M [Laboratoire National des Champs Magnetiques Pulses, 31432 Toulouse Cedex 04 (France); Rakoto, H [Laboratoire National des Champs Magnetiques Pulses, 31432 Toulouse Cedex 04 (France); Mennerich, C [Institut fuer Physik der Kondens. Materie, TU Braunschweig, 38106 Braunschweig (Germany); Klauss, H-H [Institut fuer Physik der Kondens. Materie, TU Braunschweig, 38106 Braunschweig (Germany); Demeshko, S [Georg-August-University Goettingen, Institute of Inorg. Chem., 37077 Goettingen (Germany); Leibeling, G [Georg-August-University Goettingen, Institute of Inorg. Chem., 37077 Goettingen (Germany); Meyer, F [Georg-August-University Goettingen, Institute of Inorg. Chem., 37077 Goettingen (Germany)

    2006-11-15

    High frequency Electron Spin Resonance (ESR) up to {nu} = 1 THz and magnetization M(B) of a tetranuclear-Ni(II) single molecular complex of type [L{sub 2}Ni{sub 4}(N{sub 3})(O{sub 2}CAda){sub 4}](ClO{sub 4}) featuring an unprecedented central {mu}{sub 4} - 1,1,3,3 azide have been studied in magnetic fields up to B = 55T. Bridging ligands provide intramolecular exchange paths of different strength between the four Ni ions each having a spin S{sub Ni} = 1. T- and {nu}-dependent ESR measurements enable to accurately determine the energy spectrum of the spin states of the cluster as a function of B. A predominantly antiferromagnetic character of exchange renders the ground state nonmagnetic, S = 0, with a number of excited magnetic multiplet states, S = 1,. . . ,4. Remarkably, ESR gives evidence for the spin-level crossing in a field of {approx} 25T which turns the ground state of the cluster to a strongly magnetic one. This observation is confirmed by the static M(B) data.

  10. Synthesis, Molecular Structure and Cytotoxicity of Molecular Materials Based on Water Soluble Half-Sandwich Rh(III and Ir(III Tetranuclear Metalla-Cycles

    Directory of Open Access Journals (Sweden)

    Gajendra Gupta

    2013-11-01

    Full Text Available The neutral dinuclear complexes [(η5-C5Me52Rh2(μ-dhnqCl2] (1 and [(η5-C5Me52Ir2(μ-dhnqCl2] (2 (dhnqH2 = 5,8-dihydroxy-1,4-naphthoquinone were obtained from the reaction of [(η5-C5Me5M(μ-ClCl]2 (M = Rh, Ir with dhnqH2 in the presence of CH3COONa. Treatment of 1 or 2 in methanol with linear ditopic ligands L (L = pyrazine, 4,4′-bipyridine or 1,2-bis(4-pyridylethylene, in the presence of AgCF3SO3, affords the corresponding tetranuclear metalla-rectangles [(η5-C5Me54M4(μ-dhnq2(μ-L2]4+ (L = pyrazine, M = Rh, 3; M = Ir, 4; L = 4,4′-bipyridine, M = Rh, 5; M = Ir, 6; L = 1,2-bis(4-pyridylethylene, M = Rh, 7; M = Ir, 8. All complexes were isolated as their triflate salts and were fully characterized by infrared, 1H and 13C NMR spectroscopy, and some representative complexes by single-crystal X-ray structure analysis. The X-ray structures of 3, 5 and 6 confirm the formation of the tetranuclear metalla-cycles, and suggest that complexes 5 and 6 possess a cavity of sufficient size to encapsulate small guest molecules. In addition, the antiproliferative activity of the metalla-cycles 3–8 was evaluated against the human ovarian A2780 (cisplatin sensitive and A2780cisR (cisplatin resistant cancer cell lines and on non-tumorigenic human embryonic kidney HEK293 cells. All cationic tetranuclear metalla-rectangles were found to be highly cytotoxic, with IC50 values in the low micromolar range.

  11. Targeted water soluble copper-tetrazolate complexes: interactions with biomolecules and catecholase like activities.

    Science.gov (United States)

    Saha, Manideepa; Das, Mriganka; Nasani, Rajendar; Choudhuri, Indrani; Yousufuddin, Muhammed; Nayek, Hari Pada; Shaikh, Mobin M; Pathak, Biswarup; Mukhopadhyay, Suman

    2015-12-14

    Two new mononuclear water soluble copper(II) complexes, [Cu{(5-pyrazinyl)tetrazolate}2(1,10-phenanthroline)] 1 and [Cu{(5-pyrazinyl)tetrazolate}(1,10-phenanthroline)2](NO3)0.5(N3)0.5 2, have been synthesized using the metal mediated [2 + 3] cycloaddition reaction between copper bound azide and pyrazinecarbonitrile. The interactions of these copper tetrazolate complexes 1 and 2 with biomolecules like DNA and bovine serum albumin (BSA) are studied and the catecholase like catalytic activity of compound 2 is also explored. Structural determination reveals that both compounds 1 and 2 are octahedral in nature. Screening tests were conducted to quantify the binding ability of complexes (1 and 2) towards DNA and it was revealed that complex 2 has a stronger affinity to bind to CT-DNA. DFT studies indicated that a lower HOMO-LUMO energy gap between the DNA fragment and metal complexes might be the reason for this type of stronger interaction. DNA cleavage activity was explored by gel-electrophoresis and moderate to strong DNA cleavage properties were observed in the presence and absence of co-reagents. Inhibition of cleavage in the presence of sodium azide indicates the propagation of the activity through the production of singlet molecular oxygen. Furthermore enzyme kinetic studies reflect that complex 2 is also effective in mimicking catecholase like activities. An ESI-MS spectral study indicates the probable involvement of dimeric species [(phen)2Cu-(OH)2-Cu(phen)2](2+) in the catalytic cycle.

  12. Synthesis, characterization, DNA binding and cleavage studies of mixed-ligand copper (II complexes

    Directory of Open Access Journals (Sweden)

    M. Sunita

    2017-05-01

    Full Text Available New two copper complexes of type [Cu(Bzimpy(LH2O]SO4 (where L = 2,2′ bipyridine (bpy, and ethylene diamine (en, Bzimpy = 2,6-bis(benzimidazole-2ylpyridine have been synthesized and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. Based on elemental and spectral studies six coordinated geometries were assigned to the two complexes. DNA-binding properties of these metal complexes were investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation methods. Experimental studies suggest that the complexes bind to DNA through intercalation. These complexes also promote the cleavage of plasmid pBR322, in the presence of H2O2.

  13. Synthesis and spectroscopic study of copper(II) and manganese(II) complexes with pipemidic acid.

    Science.gov (United States)

    Szymańska, Beata; Skrzypek, Danuta; Kovala-Demertzi, Dimitra; Staninska, Malgorzata; Demertzis, Mavroudis A

    2006-03-01

    The interaction of copper(II) and manganese(II) with pipemidic acid, Hpipem, afforded the complexes [Cu(pipem)(2)(H(2)O)] x 2H(2)O, 1 and [Mn(pipem)(2)(H(2)O)], 2. The new complexes have been characterised by elemental analyses, infrared, UV-vis and X-band EPR spectroscopy in the temperature range from 4 to 300 K. The monoanion, pipem, exhibits O,O ligation through the carbonyl and carboxylato oxygen atoms. Five coordinate square-pyramid configuration has been proposed for 1 and 2, and the fifth apical position is occupied by a coordinated water molecule.

  14. Synthesis and spectroscopic study of copper(II) and manganese(II) complexes with pipemidic acid

    Science.gov (United States)

    Szymańska, Beata; Skrzypek, Danuta; Kovala-Demertzi, Dimitra; Staninska, Malgorzata; Demertzis, Mavroudis A.

    2006-03-01

    The interaction of copper(II) and manganese(II) with pipemidic acid, Hpipem, afforded the complexes [Cu(pipem) 2(H 2O)]·2H 2O, 1 and [Mn(pipem) 2(H 2O)], 2. The new complexes have been characterised by elemental analyses, infrared, UV-vis and X-band EPR spectroscopy in the temperature range from 4 to 300 K. The monoanion, pipem, exhibits O,O ligation through the carbonyl and carboxylato oxygen atoms. Five coordinate square-pyramid configuration has been proposed for 1 and 2, and the fifth apical position is occupied by a coordinated water molecule.

  15. Mononuclear and binuclear copper(II) complexes of the antiinflammatory drug ibuprofen: synthesis, characterization, and catecholase-mimetic activity.

    Science.gov (United States)

    Abuhijleh, A L

    1994-09-01

    Two mononuclear copper(II) ibuprofenate adducts with imidazole or 2-methylimidazole and two binuclear copper(II) ibuprofenate adducts with metronidazole or caffeine have been prepared and characterized. Elemental analyses, UV-VIS, IR, EPR, and magnetic moment data for imidazole or 2-methylimidazole adducts are consistent with mononuclear square planar complexes that contain two ibuprofenato ligands and two N-containing imidazole ligands to give essentially a CuO2N2 chromophore. The above data for metronidazole or caffeine adducts are consistent with a binuclear structure as found for copper(II) acetate monohydrate and other copper(II) carboxylate dimers. In these complexes four carboxylate groups are bridging two copper(II) atoms, and two added bases coordinated at axial positions to form CuO4N chromophore around each copper. The catecholase-mimetic catalytic activities of the complexes have been determined by monitoring the formation of o-quinone from catechol. The catalytic activities of the mononuclear complexes are lower than those of the binuclear copper(II) ibuprofenate or its metronidazole or caffeine mono-adducts.

  16. Synthesis and Characterization of the Ligand Based on Benzimidazole and Its Copper Complex: DNA Binding and Antioxidant Activity

    OpenAIRE

    Wu, Huilu; Kou, Fan; Jia, Fei; Liu, Bin; Yuan, Jingkun; Bai, Ying

    2011-01-01

    A new copper(II) complex with formulae of [Cu(buobb)2](pic)2, where buobb stands for the ligand of 1,3-bis(1- butylbenzimidazol-2-yl)-2-oxopropane and pic represents 2,4,6-trinitrophenol, has been synthesized and characterized by elemental analyses, molar conductivity, IR, UV-Vis spectra measurements, and cyclic voltammetry. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The coordination environment around each copper(II) atom can be d...

  17. Mechanistic insight on the catecholase activity of dinuclear copper complexes with distant metal centers.

    Science.gov (United States)

    Mendoza-Quijano, María Rosa; Ferrer-Sueta, Gerardo; Flores-Álamo, Marcos; Aliaga-Alcalde, Núria; Gómez-Vidales, Virginia; Ugalde-Saldívar, Víctor M; Gasque, Laura

    2012-04-28

    The catecholase activity of two dinuclear Cu(II) complexes with distant metal centers is discussed together with solid state and solution studies. The crystal structure for one of them, [Cu(2)(diep)(H(2)O)(4)](ClO(4))(4)·2H(2)O, is described, showing the two copper ions are 7.457 Å apart and in a square pyramidal coordination. Both complexes display a weak antiferromagnetic coupling in the solid state that is manifest in the dimer EPR spectra obtained in frozen solution. The pH-potentiometric speciation performed in 1:1 MeOH-H(2)O allowed the assignment of hydrolyzed copper species as those catalytically active in the oxidation of 3,5-di-tert-butylcatechol (DTBC). The kinetic measurements led us to propose behavior consistent with Michaelis-Menten plus a linear dependence of the initial rate on [DTBC]. This can be associated with the presence of more than one catalytically active species, which is consistent with the evidence of several differently hydrolyzed species shown in the predominance diagrams. Product characterization studies led to establishing the formation of hydrogen peroxide during the catalytic cycle, while semiquinone and superoxide radicals were detected by EPR spectroscopy, supporting one-electron transference at each of the copper centers. This journal is © The Royal Society of Chemistry 2012

  18. Spontaneous and Directional Bubble Transport on Porous Copper Wires with Complex Shapes in Aqueous Media.

    Science.gov (United States)

    Li, Wenjing; Zhang, Jingjing; Xue, Zhongxin; Wang, Jingming; Jiang, Lei

    2018-01-24

    Manipulation of gas bubble behaviors is crucial for gas bubble-related applications. Generally, the manipulation of gas bubble behaviors generally takes advantage of their buoyancy force. It is very difficult to control the transportation of gas bubbles in a specific direction. Several approaches have been developed to collect and transport bubbles in aqueous media; however, most reliable and effective manipulation of gas bubbles in aqueous media occurs on the interfaces with simple shapes (i.e., cylinder and cone shapes). Reliable strategies for spontaneous and directional transport of gas bubbles on interfaces with complex shapes remain enormously challenging. Herein, a type of 3D gradient porous network was constructed on copper wire interfaces, with rectangle, wave, and helix shapes. The superhydrophobic copper wires were immersed in water, and continuous and stable gas films then formed on the interfaces. With the assistance of the Laplace pressure gradient between two bubbles, gas bubbles (including microscopic gas bubbles) in the aqueous media were subsequently transported, continuously and directionally, on the copper wires with complex shapes. The small gas bubbles always moved to the larger ones.

  19. Enantiopure copper(II) complex of natural product rosin derivative: DNA binding, DNA cleavage and cytotoxicity.

    Science.gov (United States)

    Fei, Bao-Li; Yin, Bin; Li, Dong-Dong; Xu, Wu-Shuang; Lu, Yang

    2016-12-01

    To develop chiral anticancer drug candidates for molecular target DNA, the synthesis and characterization of a novel enantiomerically pure copper(II) complex [Cu 1 Cl 2 ] (2) of an optically pure ligand N-(pyridin-2-ylmethylene) dehydroabietylamine (1) was carried out. The coordination geometry of the copper center is a distorted square-planar arrangement. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. All the results reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a higher DNA binding ability. Further, 1 and 2 could cleave supercoiled pBR322 DNA by single strand and 2 displayed stronger cleavage ability in the presence of ascorbic acid. In vitro cytotoxicity of 1 and 2 against HeLa, SiHa, HepG-2 and A431 cancer cell lines was studied using CCK-8 assay. The results indicate that 2 had a superior cytotoxicity than 1 and the widely used drug cisplatin under identical conditions. Flow cytometry analysis demonstrates 2 produced death of HeLa cancer cells through an apoptotic pathway. Cell cycle analysis shows that 2 mainly arrested HeLa cells at the S phase. A novel enantiomerically pure copper(II) complex [Cu 1 Cl 2 ] (2) of an optically pure ligand N-(pyridin-2-ylmethylene) dehydroabietylamine (1), based on natural product rosin has been synthesized. 2 has the potential to act as effective anticancer drug.

  20. Infrared and electron spin resonance spectral studies of some copper purine and pyrimidine complexes

    Science.gov (United States)

    Masoud, Mamdouh S.; Abd El-Kaway, Marwa Y.

    2013-02-01

    Copper guanine and barbital complexes were prepared and characterized by elemental analyses and spectral measurements. The data typified the formation of stoichiometries 1:1 (M:L) with possible Cu-Cu interaction "association". The complexes are with different geometries: square planar, square pyramidal and tetrahedral. The mode of bonding was identified by IR spectra. EPR spectra of the powdered complexes were recorded at X band at the room temperature. Different ESR parameters were calculated and discussed: g//, g⊥, A//, , G, F, K, α2. Molecular modeling techniques and quantum chemical methods have been performed for copper complexes to correlate the chemical structures of the complexes with their physical molecular properties. Bond lengths, bond orders, bond angles, dihedral angles, close contact, dipole moment (μ), sum of the total negative charge (STNC), electronegativity (χ), chemical potential (Pi), global hardness (η), softness (σ), the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO) and the energy gap (ΔE) were calculated using PM3 semi-empirical and Molecular Mechanics (MM+) methods. The study displays a good correlation between the theoretical and experimental data which confirms the reliability of the quantum chemical methods.

  1. Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, Jan G., E-mail: gmalecki@us.edu.pl [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Łakomska, Iwona, E-mail: iwolak@chem.umk.pl [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Maroń, Anna [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Szala, Marcin [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland); Fandzloch, Marzena [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Nycz, Jacek E., E-mail: jacek.nycz@us.edu.pl [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland)

    2015-05-15

    The pseudotetrahedral complexes of [Cu(PPh{sub 3}){sub 2}(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88 ms (frozen DCM solution up to 6.7 ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. - Highlights: • Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands. • Very long lived phosphorescent copper(I) complexes. • [Cu(PPh{sub 3}){sub 2}(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9 ms). • In frozen MeOH:EtOH solution lifetime increases to 7 ms. • Quantum efficiency equal to 4.7%.

  2. Two-step flash light sintering process for enhanced adhesion between copper complex ion/silane ink and a flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Eun-Beom; Joo, Sung-Jun [Department of Mechanical Convergence Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Ahn, Heejoon [Department of Organic and Nano Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2016-03-31

    A copper complex ion ink (including copper nanoparticles, a copper precursor and a silane coupling agent) was synthesized to enhance the adhesion between the copper pattern and a polyimide (PI) substrate. Oxygen plasma treatment was performed on the polyimide substrate to initiate a chemical reaction between the complex ion ink and the polyimide. Then, a two-step flash light sintering method (consisting of preheating and main sintering) was used to sinter the copper complex ion ink. The copper complex ion patterns were characterized as a function of the weight fraction of silane coupling agent using scanning electron microscopy (SEM), a four-point probe method and adhesion testing. In addition, a bending fatigue test was performed to evaluate the reliability of the conductive copper pattern under cyclic bending. The copper pattern fabricated with copper complex ion ink containing 3 wt% silane coupling agent exhibited the highest adhesion level (5B), the lowest resistivity (7.6 μΩ·cm) and a low resistance change (18%) after the bending fatigue test. The two-step sintering method used to enhance the adhesion between the copper complex ion ink and polyimide substrate was also studied using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). - Highlights: • The copper complex ion ink with copper nanoparticles and copper precursor was fabricated. • The copper complex ion ink was sintered by two-step flash light sintering method. • The sintered copper pattern exhibited the highest adhesion level (5B). • The resistivity of sintered copper pattern was 7.6 μΩ·cm.

  3. Coordination chemistry, thermodynamics and DFT calculations of copper(II) NNOS Schiff base complexes

    Science.gov (United States)

    Esmaielzadeh, Sheida; Azimian, Leila; Shekoohi, Khadijeh; Mohammadi, Khosro

    2014-12-01

    Synthesis, magnetic and spectroscopy techniques are described for five copper(II) containing tetradentate Schiff bases are synthesized from methyl-2-(N-2";-aminoethane), (1-methyl-2";-aminoethane), (3-aminopropylamino)cyclopentenedithiocarboxylate. Molar conductance and infrared spectral evidences indicate that the complexes are four-coordinate in which the Schiff bases are coordinated as NNOS ligands. Room temperature μeff values for the complexes are 1.71-1.80 B.M. corresponding to one unpaired electron respectively. The formation constants and free energies were measured spectrophotometrically, at constant ionic strength 0.1 M (NaClO4), at 25˚C in DMF solvent. Also, the DFT calculations were carried out to determine the structural and the geometrical properties of the complexes. The DFT results are further supported by the experimental formation constants of these complexes.

  4. Synthesis, structure, and catecholase activity of bispyrazolylacetate copper(II) complexes.

    Science.gov (United States)

    Gajewska, Małgorzata J; Ching, Wei-Min; Wen, Yuh-Sheng; Hung, Chen-Hsiung

    2014-10-21

    A series of six-coordination copper(ii) complexes containing bis(3,5-di-t-butylpyrazol-1-yl)acetate (bdtbpza) and N-heterocycles or chelating aliphatic ligands have been synthesized. The steric bulkiness of bis(pyrazol-1-yl)acetate anchors two bdtbpza to situate a trans position and to adopt an O-bound monodentate coordination mode with other nitrogen bases occupying the basal plane. Five mononuclear mixed ligand complexes, [Cu(bdtbpza)2(py)4] , [Cu(bdtbpza)2(t-Bupy)4] , [Cu(bdtbpza)2(pym)2(MeOH)2] , [Cu(bdtbpza)2(eda)2] , [Cu(bdtbpza)2(tmeda)(H2O)2] , where py = pyridine, t-Bupy = tert-butylpyridine, pym = pyrimidine, eda = ethylenediamine, and tmeda = tetramethylethylenediamine, were isolated and thoroughly characterized. Intriguingly, the heteroleptic complex , which has two aquo-ligands oriented in the cis positions, demonstrates higher catecholase-like activity in performing aerial oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) than other bis(pyrazolyl)acetate-embedded copper complexes reported herein, which suggests the essential role of labile cis-aquo ligands to promote the catalytic reaction.

  5. Toward mechanical switching of surface-adsorbed [2]catenane by in situ copper complexation.

    Science.gov (United States)

    Payer, Dietmar; Rauschenbach, Stephan; Malinowski, Nicola; Konuma, Mitsuharu; Virojanadara, Chariya; Starke, Ulrich; Dietrich-Buchecker, Christiane; Collin, Jean-Paul; Sauvage, Jean-Pierre; Lin, Nian; Kern, Klaus

    2007-12-19

    Using scanning tunneling microscopy (STM), electrospray ionization mass spectrometry (ESI-MS), and X-ray photoelectron spectroscopy (XPS), we demonstrate that a free [2]catenane consisting of two interlocking 30-membered rings (cat-30) can be deposited on a Ag(111) surface by vacuum sublimation without decomposition. The deposited cat-30 molecules self-organize as ordered dimer chain structures at the surface, presumably via intermolecular pi-pi stacking. An in situ addition of Cu atoms to the surface-adsorbed catenanes induces a drastic change in the molecular organization, i.e., from the dimer chain structure to isolated species. The nitrogen core level spectra suggest that the cat-30 phenanthroline units coordinate with Cu, indicating that the free catenane has been transformed into a Cu-complexed [2]catenane. Since it is known that the two interlocked macrocyclic rings of the free ligand cat-30 completely rearrange, i.e., circumrotate, upon complexation to copper, our results reveal that when adsorbed on the silver surface, the two macrocyclic rings of the free [2]catenane can glide within one another so as to generate the corresponding copper complex by in situ Cu complexation.

  6. Spectroscopic studies on the interaction of DNA with the copper complexes of NSAIDs lornoxicam and isoxicam.

    Science.gov (United States)

    Goswami, Sathi; Ray, Suhita; Sarkar, Munna

    2016-12-01

    Non Steroidal Anti-inflammatory Drugs (NSAIDs) form the most common class of anti-inflammatory and analgesic agents. They also show anticancer properties for which they exert their effects by interacting at the protein but not at the genomic level. This is because most NSAIDs are anions at physiological pH, which prohibit their approach to the polyanionic DNA backbone. Complexing NSAIDs with bioactive metal like copper obliterates this disadvantage. Here, copper complexes of two oxicam NSAIDs, Lornoxicam (Lx) and Isoxicam (Isx) have been chosen to study their interaction with calf thymus (ct) DNA and have been synthesized as per reported protocols. UV-vis absorption showed that DNA binding to Cu(II)-Lx complex alters the absorption spectra indicating changes in the electronic environment of the complex, whereas, for Cu(II)-Isx there was only small changes. Hence, UV-vis absorption was used to determine the binding constant, stoichiometry and thermodynamic parameters of Cu(II)-Lx. However, UV-melting studies and CD difference spectra showed that both Cu(II)-Lx and Cu(II)-Isx can interact with the DNA backbone albeit with different binding modes. The probable binding mode was determined by kinetics of EtBr displacement and viscosity measurements. Our results point to an intercalative mode of binding for Cu(II)-Lx and external groove binding for Cu(II)-Isx. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Copper homeostasis in Drosophila by complex interplay of import, storage and behavioral avoidance

    OpenAIRE

    Balamurugan, Kuppusamy; Egli, Dieter; Hua, Haiqing; Rajaram, Rama; Seisenbacher, Gerhard; Georgiev, Oleg; Schaffner, Walter

    2007-01-01

    Copper is an essential but potentially toxic trace element. In Drosophila, the metal-responsive transcription factor (MTF-1) plays a dual role in copper homeostasis: at limiting copper concentrations, it induces the Ctr1B copper importer gene, whereas at high copper concentrations, it mainly induces the metallothionein genes. Here we find that, despite the downregulation of the Ctr1B gene at high copper concentrations, the protein persists on the plasma membrane of intestinal cells for many h...

  8. Comparison of availability of copper(II) complexes with organic ligands to bacterial cells and to chitin

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, M.T.S.D.; Azenha, M.A.O. [Laquipai, Porto (Portugal). Faculdade de Ciencias do Porto; Cabral, J.P.S. [Inst. de Botanica e Centro de Citologia Experimental U.P., Porto (Portugal)

    1997-10-01

    Bacterial cells or chitin were exposed to solutions with 100 {micro}M total but only 5 {micro}M free copper, due to the presence of a proper concentration of proline, lysine, cysteine, or ethylenediamine tetraacetate (EDTA). The influence of the nature and concentration of the particles and soluble ligands, on the sorption and on the desorption of the copper, at pH 6.50 and 25.0 C, was investigated. The metal sorbed by the particles and that left in the solution were measured by atomic absorption spectrometry, after different periods of contact between particles and solution. The interpretation of the results was based on the copper(II) speciation calculated through equilibrium approaches applied to homogeneous or heterogeneous systems. A significant fraction of copper bound to the organic ligands was displaced to the bacteria or chitin, and the extent of chemical reaction depended on the nature of both the soluble (or leaving) ligands and sites on the particle surface (or entering ligands), as expected by the equilibrium theory. But with chitin, the uptake of copper in the presence of cysteine or EDTA was higher than expected, which may be due to the adsorption of the soluble copper complexes on the particle surface. In consequence of a competition between soluble and particulate ligands (cells or chitin), the free copper(II) concentration decreased in the solution, even in the presence of very strong chelators. The results indicate that copper availability is not a simple function of the initial free copper concentration in the solution. Desorption of the previously fixed copper, originated by free soluble ligands indicated that the sorption of copper was quasireversible for both particles, though a larger dismissal of the equilibrium position occurred for the cells, probably due to their biological activity.

  9. Comparative in vivo stability of copper-64-labeled cross-bridged and conventional tetraazamacrocyclic complexes.

    Science.gov (United States)

    Boswell, C Andrew; Sun, Xiankai; Niu, Weijun; Weisman, Gary R; Wong, Edward H; Rheingold, Arnold L; Anderson, Carolyn J

    2004-03-11

    The increased use of copper radioisotopes in radiopharmaceutical applications has created a need for bifunctional chelators (BFCs) that form stable radiocopper complexes and allow covalent attachment to biological molecules. The chelators most commonly utilized for labeling copper radionuclides to biomolecules are analogues of 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid (TETA); however, recent reports have communicated the instability of the radio-Cu(II)-TETA complexes in vivo. A class of bicyclic tetraazamacrocycles, the ethylene "cross-bridged" cyclam (CB-cyclam) derivatives, form highly kinetically stable complexes with Cu(II) and therefore may be less susceptible to transchelation than their nonbridged analogues in vivo. Herein we report results on the relative biological stabilities and identification of the resulting radiolabeled metabolites of a series of (64)Cu-labeled macrocyclic complexes. Metabolism studies in normal rat liver have revealed that the (64)Cu complex of 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane ((64)Cu-CB-TE2A) resulted in significantly lower values of protein-associated (64)Cu than (64)Cu-TETA [13 +/- 6% vs 75 +/- 9% at 4 h]. A similar trend was observed for the corresponding cyclen derivatives, with the (64)Cu complex of 4,10-bis(carboxymethyl)-1,4,7,10-tetraazabicyclo[5.5.2]tetradecane ((64)Cu-CB-DO2A) undergoing less transchelation than the (64)Cu complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid ((64)Cu-DOTA) [61 +/- 14% vs 90.3 +/- 0.5% protein associated (64)Cu at 4 h]. These data indicate that the structurally reinforcing cross-bridge enhances in vivo stability by reducing metal loss to protein in both the cyclam and cyclen cross-bridged (64)Cu complexes and that (64)Cu-CB-TE2A is superior to (64)Cu-CB-DO2A in that regard. These findings further suggest that a bifunctional chelator derivative of CB-TE2A is a highly desirable alternative for labeling copper radionuclides to

  10. Enantioselective Hydrolysis of Amino Acid Esters Promoted by Bis(β-cyclodextrin) Copper Complexes

    Science.gov (United States)

    Xue, Shan-Shan; Zhao, Meng; Ke, Zhuo-Feng; Cheng, Bei-Chen; Su, Hua; Cao, Qian; Cao, Zhen-Kun; Wang, Jun; Ji, Liang-Nian; Mao, Zong-Wan

    2016-02-01

    It is challenging to create artificial catalysts that approach enzymes with regard to catalytic efficiency and selectivity. The enantioselective catalysis ranks the privileged characteristic of enzymatic transformations. Here, we report two pyridine-linked bis(β-cyclodextrin) (bisCD) copper(II) complexes that enantioselectively hydrolyse chiral esters. Hydrolytic kinetic resolution of three pairs of amino acid ester enantiomers (S1-S3) at neutral pH indicated that the “back-to-back” bisCD complex CuL1 favoured higher catalytic efficiency and more pronounced enantioselectivity than the “face-to-face” complex CuL2. The best enantioselectivity was observed for N-Boc-phenylalanine 4-nitrophenyl ester (S2) enantiomers promoted by CuL1, which exhibited an enantiomer selectivity of 15.7. We observed preferential hydrolysis of L-S2 by CuL1, even in racemic S2, through chiral high-performance liquid chromatography (HPLC). We demonstrated that the enantioselective hydrolysis was related to the cooperative roles of the intramolecular flanking chiral CD cavities with the coordinated copper ion, according to the results of electrospray ionization mass spectrometry (ESI-MS), inhibition experiments, rotating-frame nuclear Overhauser effect spectroscopy (ROESY), and theoretical calculations. Although the catalytic parameters lag behind the level of enzymatic transformation, this study confirms the cooperative effect of the first and second coordination spheres of artificial catalysts in enantioselectivity and provides hints that may guide future explorations of enzyme mimics.

  11. Supramolecular architecture of metal-organic frameworks involving dinuclear copper paddle-wheel complexes.

    Science.gov (United States)

    Gomathi, Sundaramoorthy; Muthiah, Packianathan Thomas

    2013-12-15

    The two centrosymmetric dinuclear copper paddle-wheel complexes tetrakis(μ-4-hydroxybenzoato-κ(2)O:O')bis[aquacopper(II)] dimethylformamide disolvate dihydrate, [Cu2(C7H5O3)4(H2O)2]·2C3H7NO·2H2O, (I), and tetrakis(μ-4-methoxybenzoato-κ(2)O:O')bis[(dimethylformamide-κO)copper(II)], [Cu2(C8H7O3)4(C3H7NO)2], (II), crystallize with half of the dinuclear paddle-wheel cage unit in the asymmetric unit and, in addition, complex (I) has one dimethylformamide (DMF) and one water solvent molecule in the asymmetric unit. In both (I) and (II), two Cu(II) ions are bridged by four syn,syn-η(1):η(1):μ carboxylate groups, showing a paddle-wheel cage-type structure with a square-pyramidal coordination geometry. The equatorial positions of (I) and (II) are occupied by the carboxylate groups of 4-hydroxy- and 4-methoxybenzoate ligands, and the axial positions are occupied by aqua and DMF ligands, respectively. The three-dimensional supramolecular metal-organic framework of (I) consists of three different R2(2)(20) and an R4(4)(36) ring motif formed via O-H···O and OW-HW···O hydrogen bonds. Complex (II) simply packs as molecular species.

  12. Interaction of a copper (II) complex containing an artificial sweetener (aspartame) with calf thymus DNA.

    Science.gov (United States)

    Shahabadi, Nahid; Khodaei, Mohammad Mehdi; Kashanian, Soheila; Kheirdoosh, Fahimeh

    2014-01-01

    A copper (II) complex containing aspartame (APM) as ligand, Cu(APM)2Cl2⋅2H2O, was synthesized and characterized. In vitro binding interaction of this complex with native calf thymus DNA (CT-DNA) was studied at physiological pH. The interaction was studied using different methods: spectrophotometric, spectrofluorometric, competition experiment, circular dichroism (CD) and viscosimetric techniques. Hyperchromicity was observed in UV absorption band of Cu(APM)2Cl2⋅2H2O. A strong fluorescence quenching reaction of DNA to Cu(APM)2Cl2⋅2H2O was observed and the binding constants (Kf) and corresponding numbers of binding sites (n) were calculated at different temperatures. Thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS) were calculated to be+89.3 kJ mol(-1) and+379.3 J mol(-1) K(-1) according to Van't Hoff equation which indicated that reaction is predominantly entropically driven. Experimental results from spectroscopic methods were comparable and further supported by viscosity measurements. We suggest that Cu(APM)2Cl2⋅2H2O interacts with calf thymus DNA via a groove interaction mode with an intrinsic binding constant of 8×10+4 M(-1). Binding of this copper complex to DNA was found to be stronger compared to aspartame which was studied recently. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Synthesis, structure and catecholase activity of dinuclear copper and zinc complexes with an N(3)-ligand.

    Science.gov (United States)

    Kaizer, József; Pap, József; Speier, Gábor; Párkányi, László; Korecz, László; Rockenbauer, Antal

    2002-07-25

    The preparation and characterization of dinuclear [M(II)(dbcat)(idpa)](2) (M[double bond]Zn (1), Cu (3); dbcat[double bond]3,5-di-tert-butylcatecholate; idpa[double bond]3,3'-iminobis(N,N-dimethylpropylamine)) complexes are described. Crystallographic characterization of the complex [Cu(II)(dbcat)(idpa)](2) has shown that the co-ordination geometry around copper(II) ions is distorted square pyramidal (triclinic, P-1, a=10.576(1) A, b=11.927(1) A, c=12.621(1) A, alpha=77.89(1) degrees, beta=88.65(1) degrees, gamma=70.21(1) degrees, V=1462.7(2) A(3), Z=2, R=0.0387). Both 1 and 3 were suitable catalysts for the catalytic oxidation of dbcatH(2) to dtbq (dtbq=3,5-di-tert-butyl-1,2-benzoquinone) with dioxygen at ambient conditions in good yields. However, on the basis of kinetic studies the copper- and zinc-catalyzed reactions showed different mechanisms. In the first case valence tautomerism [Cu(II)(dbcat)(idpa)][Cu(I)(dbsq)(idpa)] precedes the reaction with O(2), while with the zinc complex metal-bound catecholate reacts directly with O(2) with the formation of free superoxide anion.

  14. Synthesis and Characterization of Novel Thiourea Derivatives and Their Nickel and Copper Complexes

    OpenAIRE

    Gün Binzet; Gülten Kavak; Nevzat Külcü; Süheyla Özbey; Ulrich Flörke; Hakan Arslan

    2013-01-01

    New benzoyl thiourea derivatives and their nickel and copper complexes were synthesized. The structure of the synthesized compounds were confirmed by elemental analysis, FT-IR, and 1H NMR techniques. Four of the synthesized compounds are analyzed by X-ray single crystal diffraction technique. Whereas N,N-dimethyl-N′-(4-fluorobenzoyl)thiourea, N,N-diethyl-N′-(4-fluorobenzoyl)thiourea, and N,N-di-n-butyl-N′-(4-fluorobenzoyl) thiourea crystallize in the monoclinic system, bis(N,N-di-n-propyl-N′-...

  15. Theoretical Study of Copper Complexes: Molecular Structure, Properties, and Its Application to Solar Cells

    Directory of Open Access Journals (Sweden)

    Jesus Baldenebro-Lopez

    2013-01-01

    Full Text Available We present a theoretical investigation of copper complexes with potential applications as sensitizers for solar cells. The density functional theory (DFT and time-dependent DFT were utilized, using the M06 hybrid meta-GGA functional with the LANL2DZ (D95V on first row and DZVP basis sets. This level of calculation was used to find the optimized molecular structure, the absorption spectra, the molecular orbitals energies, and the chemical reactivity parameters that arise from conceptual DFT. Solvent effects have been taken into account by an implicit approach, namely, the polarizable continuum model (PCM, using the nonequilibrium version of the IEF-PCM model.

  16. Copper (II) complexes possessing alkyl-substituted polypyridyl ligands: Structural characterization and in vitro antitumor activity.

    Science.gov (United States)

    Angel, Noah R; Khatib, Raneen M; Jenkins, Julia; Smith, Michelle; Rubalcava, Justin M; Le, Brian Khoa; Lussier, Daniel; Chen, Zhuo Georgia; Tham, Fook S; Wilson, Emma H; Eichler, Jack F

    2017-01-01

    In an effort to find alternatives to the antitumor drug cisplatin, a series of copper (II) complexes possessing alkyl-substituted polypyridyl ligands have been synthesized. Eight new complexes are reported herein: μ-dichloro-bis{2,9-di-sec-butyl-1,10-phenanthrolinechlorocopper(II)} {[((di-sec-butyl)phen)ClCu(μ-Cl)2CuCl((di-sec-butyl)phen)]}(1), 2-sec-butyl-1,10-phenanthrolinedichlorocopper(II) {([mono-sec-butyl)phen) CuCl2} (2), 2,9-di-n-butyl-1,10-phenanthrolinedichlorocopper(II) {[(di-n-butyl)phen) CuCl2}(3), 2-n-butyl-1,10-phenanthrolinedichlorocopper(II) {[(mono-n-butyl)phen) CuCl2} (4), 2,9-di-methyl-1,10-phenanthrolineaquadichlorocopper(II) {[(di-methyl)phen) Cu(H2O)Cl2}(5), μ-dichloro-bis{6-sec-butyl-2,2'-bipyridinedichlorocopper(II)} {((mono-sec-butyl)bipy) ClCu(μ-Cl)2CuCl((mono-sec-butyl)bipy)} (6), 6,6'-di-methyl-2,2'-bipyridinedichlorocopper(II) {(6,6'-di-methyl)bipy) CuCl2} (7), and 4,4'-dimethyl-2,2'-bipyridinedichlorocopper(II) {(4,4'-di-methyl)bipy) CuCl2} (8). These complexes have been characterized via elemental analysis, UV-vis spectroscopy, and mass spectrometry. Single crystal X-ray diffraction experiments revealed the complexes synthesized with the (di-sec-butyl)phen ligand (1) and (mono-sec-butyl)bipy ligand (6) crystallized as dimers in which two copper(II) centers are bridged by two chloride ligands. Conversely, complexes 2, 7, and 8 were isolated as monomeric species possessing distorted tetrahedral geometries, and the [((di-methyl)phen)Cu(H2O)Cl2] (5) complex was isolated as a distorted square pyramidal monomer possessing a coordinating aqua ligand. Compounds 1-8 were evaluated for their in vitro antitumor efficacy. Compounds 1, 5, and 7 in particular were found to exhibit remarkable activity against human derived lung cancer cells, yet this class of copper(II) compounds had minimal cytotoxic effect on non-cancerous cells. In vitro control experiments indicate the activity of the copper(II) complexes most likely does not arise from the

  17. An unprecedented tetranuclear niobium aqua ion with a capping μ4-sulfido ligand

    DEFF Research Database (Denmark)

    Ooi, Bee Lean; Søtofte, Inger

    2005-01-01

    A new niobium aqua ion, with an unprecedented metal-metal bonded tetranuclear Nb4(μ4-S)(μ2-O)54+ core, is obtained upon treatment of Zn-reduced ethanolic solutions of NbCl5 with HCl in the presence of a sulfide source. The red aqua ion, obtained upon cation-exchange chromatography, forms readily ...

  18. Synthesis, Structure, and Reactivity of Model Complexes of Copper Nitrite Reductase.

    Science.gov (United States)

    Casella, Luigi; Carugo, Oliviero; Gullotti, Michele; Doldi, Sergio; Frassoni, Massimiliano

    1996-02-28

    The copper(I) and copper(II) complexes with the nitrogen donor ligands bis[(1-methylbenzimidazol-2-yl)methyl]amine (1-BB), bis[2-(1-methylbenzimidazol-2-yl)ethyl]amine (2-BB), N-acetyl-2-BB (AcBB), and tris[2-(1-methylbenzimidazol-2-yl)ethyl]nitromethane (TB) have been studied as models for copper nitrite reductase. The copper(II) complexes form adducts with nitrite and azide that have been isolated and characterized. The Cu(II)-(1-BB) and Cu(II)-AcBB complexes are basically four-coordinated with weak axial interaction by solvent or counterion molecules, whereas the Cu(II)-(2-BB) and Cu(II)-TB complexes prefer to assume five-coordinate structures. A series of solid state structures of Cu(II)-(1-BB) and -(2-BB) complexes have been determined. [Cu(1-BB)(DMSO-O)(2)](ClO(4))(2): triclinic, P&onemacr; (No. 2), a = 9.400(1) Å, b = 10.494(2) Å, c = 16.760(2) Å, alpha = 96.67(1) degrees, beta = 97.10(1) degrees, gamma = 108.45(1) degrees, V = 1534.8(5) Å(3), Z = 2, number of unique data [I >/= 3sigma(I)] = 4438, number of refined parameters = 388, R = 0.058. [Cu(1-BB)(DMSO-O)(2)](BF(4))(2): triclinic, P&onemacr; (No. 2), a = 9.304(5) Å, b = 10.428(4) Å, c = 16.834(8) Å, alpha = 96.85(3) degrees, beta = 97.25(3) degrees, gamma = 108.21(2) degrees, V = 1517(1) Å(3), Z = 2, number of unique data [I >/= 2sigma(I)] = 3388, number of refined parameters = 397, R = 0.075. [Cu(1-BB)(DMSO-O)(NO(2))](ClO(4)): triclinic, P&onemacr; (No. 2), a = 7.533(2) Å, b = 8.936(1) Å, c = 19.168(2) Å, alpha = 97.66(1) degrees, beta = 98.62(1) degrees, gamma = 101.06(1) degrees, V = 1234.4(7) Å(3), Z = 2, number of unique data [I >/= 2sigma(I)] = 3426, number of refined parameters = 325, R = 0.081. [Cu(2-BB)(MeOH)(ClO(4))](ClO(4)): triclinic, P&onemacr; (No. 2), a = 8.493(3) Å, b = 10.846(7) Å, c = 14.484(5) Å, alpha = 93.71(4) degrees, beta = 103.13(3) degrees, gamma = 100.61(4) degrees, V = 1270(1) Å(3), Z = 2, number of unique data [I>/= 2sigma(I)] = 2612, number of refined

  19. COMMD1 is linked to the WASH complex and regulates endosomal trafficking of the copper transporter ATP7A

    NARCIS (Netherlands)

    Phillips-Krawczak, Christine A.; Singla, Amika; Starokadomskyy, Petro; Deng, Zhihui; Osborne, Douglas G.; Li, Haiying; Dick, Christopher J.; Gomez, Timothy S.; Koenecke, Megan; Zhang, Jin-San; Dai, Haiming; Sifuentes-Dominguez, Luis F.; Geng, Linda N.; Kaufmann, Scott H.; Hein, Marco Y.; Wallis, Mathew; McGaughran, Julie; Gecz, Jozef; De Sluis, Bart van; Billadeau, Daniel D.; Burstein, Ezra

    2015-01-01

    COMMD1 deficiency results in defective copper homeostasis, but the mechanism for this has remained elusive. Here we report that COMMD1 is directly linked to early endosomes through its interaction with a protein complex containing CCDC22, CCDC93, and C16orf62. This COMMD/CCDC22/CCDC93 (CCC) complex

  20. Novel UV assay for protein determination and the characterization of copper-protein complexes by mass spectrometry.

    Science.gov (United States)

    Drochioiu, G; Damoc, N E; Przybylski, M

    2006-05-15

    A very simple, highly selective and sensitive assay of proteins based on the biuret absorption in the ultraviolet region has been developed. The well-known biuret assay is based on the reaction of proteins with copper ions under strong alkaline conditions to form a copper-protein complex. Yet, copper ions may seriously interfere with the determination if the measurement is made in the UV range. In the present approach, proteins mobilize copper ions from insoluble salts at different pH values, and the copper-protein complexes are investigated by UV spectrophotometry and mass spectrometry. Upon using copper phosphate, free copper ions do not interfere with the determination from 540 to 240nm. Copper absorbance slowly increases from 240 to 190nm where a blank with the reagents is recommended. A maximum absorbance for the copper-protein complex was found at 226nm and high pH value. The stoichiometries of the copper-protein complexes measured directly with a mass spectrometer are pH dependent: half of the peptides without any histidine residue chelate just a single Cu(2+) ion at pH 7.4 but each such peptide mobilizes from 1 to 6 Cu(2+) ions at pH 10.3. To determine proteins, 1-1.5ml of 1.8% KOH solution with 0-20mugml(-1) protein is treated with 25mg of copper phosphate powder. The mixture is powerfully stirred, centrifuged, and the absorbance of the supernatant is measured at 226nm in 1cm quartz cuvettes against a blank of the reagents. The color system obeys Beer's law in the range 0.1-20mugml(-1) protein at this wavelength. The molar absorptivity value proved to be a characteristic of each protein being analyzed. Therefore, individual proteins should be used to plot calibration curves. This assay proved to be over 100 times more sensitive than the classical biuret procedure. The method is highly selective and the determination is little affected by the presence of other substances. All other important analytical parameters were studied and practical applicability of

  1. Solvent-less Synthesis, Antimalarial and Toxicity Evaluation of Lumefantrine-Copper Complex in Swiss Mice

    Directory of Open Access Journals (Sweden)

    Rotimi Olusanya ARISE

    2016-09-01

    Full Text Available The antimalarial efficacy and safety of mechanically induced solventlessly synthesized lumefantrine-copper complex were investigated in experimental mice. Parasite level in Plasmodium berghei-infected mice treated with lumefantrine - copper complex (LCC significantly declined (p < 0.05 at day 3 and was comparable with that of chloroquine-treated mice. LCC attained a percentage chemo-suppression which was significantly higher than those of pure lumefantrine and comparable with chloroquine. Pure lumefantrine attained a clearance of 88.52%, chloroquine was 91.95%, while LCC was 95.10%. Administration of lumefantrine, LCC and chloroquine to mice for 7 days caused a significant increase (p < 0.05 in the activities of alkaline phosphatase, acid phosphatase and lactate dehydrogenase in the liver when compared with the control, and a significant reduction (p < 0.05 in the liver and kidney activities of alanine and aspartate aminotransferases when compared with the control. Also, there was a significant decrease (p < 0.05 in the levels of PCV, Hb, RBC and lymphocytes and a significant increase (p < 0.05 in the white blood cells count and neutrophil counts in all the treatment groups when compared with control. Alterations in the biochemical parameters and chromosomal aberration in the organs investigated suggested selective, chromosomal and functional toxicity of the tested drugs.

  2. Chiral copper(II) complex based on natural product rosin derivative as promising antitumour agent.

    Science.gov (United States)

    Fei, Bao-Li; Huang, Zhi-Xiang; Xu, Wu-Shuang; Li, Dong-Dong; Lu, Yang; Gao, Wei-Lin; Zhao, Yue; Zhang, Yu; Liu, Qing-Bo

    2016-07-01

    To evaluate the biological preference of chiral drug candidates for molecular target DNA, the synthesis and characterization of a chiral copper(II) complex (2) of a chiral ligand N,N'-(pyridin-2-ylmethylene) dehydroabietylamine (1) was carried out. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral, emission spectral and viscosity analysis reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a higher DNA binding ability. In the absence/presence of ascorbic acid, 1 and 2 cleaved supercoiled pBR322 DNA by single-strand and 2 displayed stronger DNA cleavage ability. In addition, in vitro cytotoxicity of 1 and 2 against HeLa, SiHa, HepG-2 and A431 cancer cell lines study show that they exhibited effective cytotoxicity against the tested cell lines, notably, 2 showed a superior cytotoxicity than the widely used drug cisplatin under identical conditions, indicating it has the potential to act as effective anticancer drug. Flow cytometry analysis indicates 2 produced death of HeLa cancer cells through an apoptotic pathway. Cell cycle analysis demonstrates that 2 mainly arrested HeLa cells at the S phase. The study represents the first step towards understanding the mode of the promising chiral rosin-derivative based copper complexes as chemotherapeutics. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Molecular recognition between DNA and a copper-based anticancer complex.

    Science.gov (United States)

    Galindo-Murillo, Rodrigo; Ruíz-Azuara, Lena; Moreno-Esparza, Rafael; Cortés-Guzmán, Fernando

    2012-11-28

    The aim of this work is to describe the specific recognition site between DNA and an anticancer copper complex by means of computational methods. Molecular dynamics were used to find the preferred site of binding between selected DNA chains and [Cu(2,2'-bipyridine)(acetylacetonate)(H(2)O)](+) (Cas). Full DFT optimizations of selected geometries extracted from simulations, followed by a topological analysis of electron density allowed us to define the specific interactions inside the recognition site. Cas links deoxyribose-phosphate by a coordination bond between metal and the phosphate group. There are several C-H···π, O···π(C) and O···π(N) interactions between the sugar group and the aromatic ligand of Cas. The results indicate that the adduct Cas-deoxyribose-phosphate may be an initial step toward the hydrolysis of DNA chains. Overall, this study provides insights into the initial step of the action mechanism of copper complexes as apoptosis-inducing agents and provides guidelines for the design of this kind of drugs.

  4. Effect of glutamic acid on copper sorption onto kaolinite - Batch experiments and surface complexation modeling.

    Science.gov (United States)

    Karimzadeh, Lotfollah; Barthen, Robert; Stockmann, Madlen; Gruendig, Marion; Franke, Karsten; Lippmann-Pipke, Johanna

    2017-07-01

    High carbonate content of the European Kupferschiefer ore deposits is a challenge for acid copper leaching (pH ≤ 2). Therefore investigating the mobility behavior of Cu(II) under conditions related to an alternative, neutrophil biohydrometallurgical Cu(II) leaching approach is of interest. As glutamic acid (Glu) might be present as a component in the growth media, we studied its effects on the adsorption of Cu(II) onto kaolinite. The binary and ternary batch sorption measurements of Cu(II) and Glu onto kaolinite were performed in the presence of 10 mM NaClO 4 as background electrolyte and at a pH range from 4 to 9. Sorption experiments were modeled by the charge-distribution multi-site ion complexation (CD-MUSIC) model by using single sorption site (≡SOH) and monodentate surface complexation reactions. Glu sorption on kaolinite is weak (copper mobility. The results of isotherms show that Cu(II)-Glu sorption onto kaolinite mimics the Freundlich model. The proposed CD-MUSIC model provides a close fit to the experimental data and predicts the sorption of Cu(II), Cu(II)-Glu and Glu onto kaolinite as well as the effect of Glu on Cu(II) mobility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Validation data supporting the characterization of novel copper complexes as anticancer agents

    Directory of Open Access Journals (Sweden)

    Ceyda Acilan

    2016-12-01

    Full Text Available Three copper(II complexes, Cu(Sal-Gly(phen, Cu(Sal-Glypheamine, Cu(Sal-Glyphepoxy were synthesized and characterized for their anticancer properties and mechanism of action (Acilan et al., in press [1]. Here, we provide supporting data on colon cancer cell lines complementing our previous findings in cervix cells. This paper also contains a data table for the fold changes and p-values of all genes analyzed in this study via a custom RT-qPCR array. All compounds induced DNA damage (based on 8-oxo-guanidine, ɣH2AX staining in cells and apoptosis (based on elevated DNA condensation/fragmentation, Annexin V staining, caspase 3/7 activity and mitochondrial membrane depolarization in HCT-116 colon cancer cells. The increase in oxidative stress was also further confirmed in these cells. Further interpretation of the data presented here can be found in the article entitled “Synthesis, biological characterization and evaluation of molecular mechanisms of novel copper complexes as anticancer agents” (Acilan et al., in press [1].

  6. Monopicolinate cross-bridged cyclam combining very fast complexation with very high stability and inertness of its copper(II) complex.

    Science.gov (United States)

    Lima, Luís M P; Halime, Zakaria; Marion, Ronan; Camus, Nathalie; Delgado, Rita; Platas-Iglesias, Carlos; Tripier, Raphaël

    2014-05-19

    The synthesis of a new cross-bridged 1,4,8,11-tetraazacyclotetradecane (cb-cyclam) derivative bearing a picolinate arm (Hcb-te1pa) was achieved by taking advantage of the proton sponge properties of the starting constrained macrocycle. The structure of the reinforced ligand as well as its acid-base properties and coordination properties with Cu(2+) and Zn(2+) was investigated. The X-ray structure of the free ligand showed a completely preorganized conformation that lead to very fast copper(II) complexation under mild conditions (instantaneous at pH 7.4) or even in acidic pH (3 min at pH 5) at room temperature and that demonstrated high thermodynamic stability, which was measured by potentiometry (at 25 °C and 0.10 M in KNO3). The results also revealed that the complex exists as a monopositive copper(II) species in the intermediate pH range. A comparative study highlighted the important selectivity for Cu(2+) over Zn(2+). The copper(II) complex was synthesized and investigated in solution using different spectroscopic techniques and DFT calculations. The kinetic inertness of the copper(II) complex in acidic medium was evaluated by spectrophotometry, revealing the very slow dissociation of the complex. The half-life of 96 days, in 5 M HClO4, and 465 min, in 5 M HCl at 25 °C, show the high kinetic stability of the copper(II) chelate compared to that of the corresponding complexes of other macrocyclic ligands. Additionally, cyclic voltammetry experiments underlined the perfect electrochemical inertness of the complex as well as the quasi-reversible Cu(2+)/Cu(+) redox system. The coordination geometry of the copper center in the complex was established in aqueous solution from UV-vis and EPR spectroscopies.

  7. Effect of organic complexation on copper accumulation and toxicity to the estuarine red macroalga Ceramium tenuicorne: a test of the free ion activity model.

    Science.gov (United States)

    Ytreberg, Erik; Karlsson, Jenny; Hoppe, Sabina; Eklund, Britta; Ndungu, Kuria

    2011-04-01

    Current water quality criteria (WQC) regulations on copper toxicity to biota are still based on total dissolved (<0.4 μm membrane filter) copper concentrations with a hardness modification for freshwaters. There are however ongoing efforts to incorporate metal speciation in WQC and toxicity regulations (such as the biotic ligand model-BLM) for copper and other metals. Here, we show that copper accumulation and growth inhibition of the Baltic macroalga Ceramium tenuicorne exposed to copper in artificial seawater at typical coastal and estuarine DOC concentrations (similar to 2-4 mg/L-C as fulvic acid) are better correlated to weakly complexed and total dissolved copper concentrations rather than the free copper concentration [Cu2+]. Our results using a combination of competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) measurements and model calculations (using visual MINTEQ incorporating the Stockholm Humic Model) show that copper accumulation in C. tenuicorne only correlates linearly well to [Cu2+] at relatively high [Cu2+] and in the absence of fulvic acid. Thus the FIAM fails to describe copper accumulation in C. tenuicorne at copper and DOC concentrations typical of most marine waters. These results seem to indicate that at ambient total dissolved copper concentration in coastal and estuarine waters, C. tenuicorne might be able to access a sizable fraction of organically complexed copper when free copper concentration to the cell membrane is diffusion limited.

  8. Antibacterial, antibiofilm and antioxidant screening of copper(II)-complexes with some S-alkyl derivatives of thiosalicylic acid. Crystal structure of the binuclear copper(II)-complex with S-propyl derivative of thiosalicylic acid

    Science.gov (United States)

    Bukonjić, Andriana M.; Tomović, Dušan Lj.; Nikolić, Miloš V.; Mijajlović, Marina Ž.; Jevtić, Verica V.; Ratković, Zoran R.; Novaković, Slađana B.; Bogdanović, Goran A.; Radojević, Ivana D.; Maksimović, Jovana Z.; Vasić, Sava M.; Čomić, Ljiljana R.; Trifunović, Srećko R.; Radić, Gordana P.

    2017-01-01

    The spectroscopically predicted structure of the obtained copper(II)-complex with S-propyl derivative of thiosalicylic acid was confirmed by X-ray structural study. The binuclear copper(II)-complex with S-propyl derivative of thiosalicylic acid crystallized in two polymorphic forms with main structural difference in the orientation of phenyl rings relative to corresponding carboxylate groups. The antibacterial activity was tested determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by using microdilution method. The influence on bacterial biofilm formation was determined by tissue culture plate method. In general, the copper(II)-complexes manifested a selective and moderate activity. The most sensitive bacteria to the effects of Cu(II)-complexes was a clinical isolate of Pseudomonas aeruginosa. For this bacteria MIC and biofilm inhibitory concentration (BIC) values for all tested complexes were in the range or better than the positive control, doxycycline. Also, for the established biofilm of clinical isolate Staphylococcus aureus, BIC values for the copper(II)-complex with S-ethyl derivative of thiosalicylic acid,[Cu2(S-et-thiosal)4(H2O)2] (C3) and copper(II)-complex with S-butyl derivative of thiosalicylic acid, [Cu2(S-bu-thiosal)4(H2O)2] (C5) were in range or better than the positive control. All the complexes acted better against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus aureus ATCC 25923) than Gram-negative bacteria (Proteus mirabilis ATCC 12453, Pseudomonas aeruginosa, and P. aeruginosa ATCC 27855). The complexes showed weak antioxidative properties tested by two methods (1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing power assay).

  9. Enhanced reactive oxygen species through direct copper sulfide nanoparticle-doxorubicin complexation

    Science.gov (United States)

    Li, Yajuan; Cupo, Michela; Guo, Liangran; Scott, Julie; Chen, Yi-Tzai; Yan, Bingfang; Lu, Wei

    2017-12-01

    CuS-based nanostructures loading the chemotherapeutic agent doxorubicin (DOX) exerted excellent cancer photothermal chemotherapy under multi-external stimuli. The DOX loading was generally designed through electrostatic interaction or chemical linkers. However, the interaction between DOX molecules and CuS nanoparticles has not been investigated. In this work, we use PEGylated hollow copper sulfide nanoparticles (HCuSNPs) to directly load DOX through the DOX/Cu2+ chelation process. Distinctively, the synthesized PEG–HCuSNPs–DOX release the DOX/Cu2+ complexes into surrounding environment, which generate significant reactive oxygen species (ROS) in a controlled manner by near-infrared laser. The CuS nanoparticle-mediated photothermal ablation facilitates the ROS-induced cancer cell killing effect. Our current work reveals a DOX/Cu2+-mediated ROS-enhanced cell-killing effect in addition to conventional photothermal chemotherapy through the direct CuS nanoparticle-DOX complexation.

  10. Correlation of Electronic and Geometric Structure in Mononuclear Copper(II) Superoxide Complexes

    Science.gov (United States)

    Ginsbach, Jake W.; Peterson, Ryan L.; Cowley, Ryan E.; Karlin, Kenneth D.; Solomon, Edward I.

    2013-01-01

    The geometry of mononuclear copper(II) superoxide complexes has been shown to determine their ground state where side-on bonding leads to a singlet ground state and end-on complexes have triplet ground states. In apparent contrast to this trend, the recently synthesized (HIPT3tren)CuII–O2•− (1) was proposed to have an end-on geometry and a singlet ground state. However, re-examination of 1 with resonance Raman (rR), magnetic circular dichroism (MCD), and 2H NMR spectroscopy indicates that 1 is in fact an end-on superoxide species with a triplet ground state that results from the single CuII–O2•− bonding interaction being weaker than the spin pairing energy. PMID:24164429

  11. Copper(I) complexes as alternatives to iridium(III) complexes for highly efficient oxygen sensing.

    Science.gov (United States)

    Medina-Rodríguez, Santiago; Orriach-Fernández, Francisco J; Poole, Christopher; Kumar, Prashant; de la Torre-Vega, Ángel; Fernández-Sánchez, Jorge F; Baranoff, Etienne; Fernández-Gutiérrez, Alberto

    2015-07-21

    The complex [Cu(xantphos)(dmp)][PF6] (dmp = 2,9-dimethyl-1,10-phenanthroline) in a nanostructured metal oxyde matrix shows better sensitivity to oxygen (KSV = 9.74 ± 0.87 kPa(-1) between 0 and 1 kPa pO2 and 5.59 ± 0.15 kPa(-1) between 0 and 10 kPa pO2) than cyclometallated iridium complexes in the same conditions.

  12. Structural and biological aspects of copper (II) complexes with 2-methyl-3-amino-(3H)-quinazolin-4-one.

    Science.gov (United States)

    Ramadan, A M

    1997-02-15

    A series of new copper (II) complexes with 2-methyl-3-amino(3H)-quinazolin-4-one (MAQ) and various anions (Cl-, Br-, ClO(-)4, NO(-)3, SCN-, and SO(2-)4 was prepared. Their structures and properties were characterized by elemental analysis, IR, UV-Vis and ESR spectroscopy, molar conductivity, and magnetic moment measurements. The square-planar complex was only obtained in the presence of perchlorate anion, whereas the five coordinate species, which have a square-pyramidal structure, were obtained for chloro and bromo complexes. In the case of hexa coordinate complexes, in which nitrate, sulphate, or thiocyanate is attached to a copper(II) ion in a 1:2 (metal:ligand) ratio, a distorted octahedral geometry around copper(II) is proposed. The antimicrobial activity of the free ligand and its copper(II) complexes clearly illustrates that the compounds have both an antibacterial and antifungal potency against the organisms tested. In most cases, the complexes were found to be more active than the free ligand, but in some cases, an equal activity was displayed. To further elucidate the biological activity of the complexes, their activities towards active oxygen species, such as H2O2 and O(-)2, were investigated. A probable mechanism for the cytotoxic reaction with the different organisms is proposed.

  13. Synthesis, crystallographic characterization and electrochemical property of a copper(II) complex of the anticancer agent elesclomol.

    Science.gov (United States)

    Vo, Nha Huu; Xia, Zhiqiang; Hanko, Jason; Yun, Tong; Bloom, Steve; Shen, Jianhua; Koya, Keizo; Sun, Lijun; Chen, Shoujun

    2014-01-01

    Elesclomol is a novel anticancer agent that has been evaluated in a number of late stage clinical trials. A new and convenient synthesis of elesclomol and its copper complex is described. X-ray crystallographic characterization and the electrochemical properties of the elesclomol copper(II) complex are discussed. The copper(II) cation is coordinated in a highly distorted square-planar geometry to each of the sulphur and amide nitrogen atoms of elesclomol. Electrochemical measurements demonstrate that the complex undergoes a reversible one-electron reduction at biologically accessible potentials. In contrast the free elesclomol is found electrochemically inactive. This evidence is in strong support of the mechanism of action we proposed for the anticancer activity of elesclomol. © 2013.

  14. Copper-sulfenate complex from oxidation of a cavity mutant of Pseudomonas aeruginosa azurin

    Energy Technology Data Exchange (ETDEWEB)

    Sieracki, Nathan A.; Tian, Shiliang; Hadt, Ryan G.; Zhang, Jun-Long; Woertink, Julia S.; Nilges, Mark J.; Sun, Furong; Solomon, Edward I.; Lu, Yi [Stanford; (UIUC); (Peking)

    2014-08-25

    Metal–sulfenate centers are known to play important roles in biology and yet only limited examples are known due to their instability and high reactivity. Herein we report a copper–sulfenate complex characterized in a protein environment, formed at the active site of a cavity mutant of an electron transfer protein, type 1 blue copper azurin. Reaction of hydrogen peroxide with Cu(I)–M121G azurin resulted in a species with strong visible absorptions at 350 and 452 nm and a relatively low electron paramagnetic resonance gz value of 2.169 in comparison with other normal type 2 copper centers. The presence of a side-on copper–sulfenate species is supported by resonance Raman spectroscopy, electrospray mass spectrometry using isotopically enriched hydrogen peroxide, and density functional theory calculations correlated to the experimental data. In contrast, the reaction with Cu(II)–M121G or Zn(II)–M121G azurin under the same conditions did not result in Cys oxidation or copper–sulfenate formation. Structural and computational studies strongly suggest that the secondary coordination sphere noncovalent interactions are critical in stabilizing this highly reactive species, which can further react with oxygen to form a sulfinate and then a sulfonate species, as demonstrated by mass spectrometry. Engineering the electron transfer protein azurin into an active copper enzyme that forms a copper–sulfenate center and demonstrating the importance of noncovalent secondary sphere interactions in stabilizing it constitute important contributions toward the understanding of metal–sulfenate species in biological systems.

  15. DNA binding affinity of a macrocyclic copper(II) complex: Spectroscopic and molecular docking studies.

    Science.gov (United States)

    Shahabadi, Nahid; Hakimi, Mohammad; Morovati, Teimoor; Fatahi, Navid

    2017-08-03

    The interaction of a novel macrocyclic copper(II) complex, ([CuL(ClO 4 ) 2 ] that L is 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1 6,10 ]eicosane) with calf thymus DNA (ct-DNA) was investigated by various physicochemical techniques and molecular docking at simulated physiological conditions (pH = 7.4). The absorption spectra of the Cu(II) complex with ct-DNA showed a marked hyperchroism with 10 nm blue shift. The intrinsic binding constant (K b ) was determined as 1.25 × 10 4 M -1 , which is more in keeping with the groove binding with DNA. Furthermore, competitive fluorimetric studies with Hoechst33258 have shown that Cu(II) complex exhibits the ability to displace the ct-DNA-bound Hoechst33258 indicating that it binds to ct-DNA in strong competition with Hoechst33258 for the groove binding. Also, no change in the relative viscosity of ct-DNA and fluorescence intensity of ct-DNA-MB complex in the present of Cu(II) complex is another evidence to groove binding. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the binding reaction. The experimental results were in agreement with the results obtained via molecular docking study.

  16. Spectrophotometric study of etodolac complexes with copper (II) and iron (III).

    Science.gov (United States)

    Amer, Sawsan M; El-Saharty, Yasser S; Metwally, Fadia H; Younes, Kareem M

    2005-01-01

    A rapid, simple, and selective method was developed for the determination of etodolac. The method depends on complexation of etodolac with copper (II) acetate and iron (III) chloride followed by extraction of complexes with dichloromethane and then measuring the extracted complexes spectrophotometrically at 684 and 385 nm in case of Cu (II) or Fe (III), respectively. Different factors affecting the reaction, such as pH, reagent concentration, and time, were studied. By use of Job's method of continuous variation, the molar ratio method, and elemental analysis, the stoichiometry of the reaction was found to be in the ratio of 1:2 and 1:3, metal:drug in the case of Cu (II) and Fe (III), respectively. The method obeys Beer's law in a concentration range of 2.00-9.00 and 0.50-2.00 mg/mL in case of Cu (II) and Fe (III), respectively. The stability of the complexes formed was also studied, and the reaction products were isolated for further investigation. The complexes have apparent molar absorptivities of about 32.14 +/- 0.97 and 168.32 +/- 1.12 for Cu (II) and Fe (III), respectively. The suggested procedures were successfully applied to the analysis of pure etodolac and its pharmaceutical formulations. The validity of the procedures was further ascertained by the method of standard additions, and the results were compared with other reported spectrophotometric methods and showed no significant difference in accuracy and precision.

  17. Copper complexes containing thiosemicarbazones derived from 6-nitropiperonal: Antimicrobial and biophysical properties

    Science.gov (United States)

    Beckford, Floyd A.; Webb, Kelsey R.

    2017-08-01

    A series of four thiosemicarbazones from 6-nitropiperonal along with the corresponding copper complexes were synthesized. The biophysical characteristics of the complexes were investigated by the binding to DNA and human serum albumin. The binding to DNA is moderate; the binding constants run from (0.49-7.50) × 104 M- 1. In relation to HSA, the complexes interact strongly with binding constants on the order of 105 M- 1. The complexes also display antioxidant behavior as determined by the ability to scavenge diphenylpicrylhydrazyl (dpph) and nitric oxide radicals. The antimicrobial profiles of the compounds, tested against a panel of microbes including five of the ESKAPE pathogens (Staphylococcus aureus, MRSA, Escherichia coli, Klebsiella pneumoniae, MDR, Acinetobacter baumannii, Pseudomonas aeruginosa) and two yeasts (Candida albicans and Cryptococcus neoformans var. grubii), are also described. The compounds contain a core moiety that is similar to oxolinic acid, a quinolone antibiotic that targets DNA gyrase and topoisomerase (IV). The binding interaction between the complexes and these important antibacterial targets were studied by computational methods, chiefly docking studies. The calculated dissociation constants for the interaction with DNA gyrase B (from Staphylococcus aureus) range from 4.32 to 24.65 μM; the binding was much stronger to topoisomerase IV, with dissociation constants ranging from 0.37 to 1.27 μM.

  18. Synthesis, structural characterization, cytotoxic properties and DNA binding of a dinuclear copper(II) complex.

    Science.gov (United States)

    Ferreira, B J M Leite; Brandão, P; Meireles, M; Martel, Fátima; Correia-Branco, Ana; Fernandes, Diana M; Santos, T M; Félix, V

    2016-08-01

    In this study a novel dinuclear copper(II) complex with adenine and phenanthroline has been synthesized and its structure determined by single crystal X-ray diffraction. In the dinuclear complex [Cu₂(μ-adenine)₂(phen)₂(H2O)2](NO3)4·0.5H2O (phen=1,10-phenanthroline) (1) the two Cu(II) centres exhibit a distorted square pyramidal coordination geometry linked by two nitrogen donors from adenine bridges leading to a Cu-Cu distance of 3.242(3)Å. Intramolecular and intermolecular π⋯π interactions as well as an H-bonding network were observed. The antitumor capacity of the complex has been tested in vitro against human cancer cell lines, cervical carcinoma (HeLa) and colorectal adenocarcinoma (Caco-2), by metabolic tests, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as reagent. The complex 1 has remarkable low IC50 values of 0.87±0.06μM (HeLa) and 0.44±0.06μM (Caco-2), when compared with values for cisplatin against the same cell lines. The interaction of complex 1 with calf thymus DNA (CT DNA) was further investigated by absorption and fluorescence spectroscopic methods. A binding constant of 5.09×10(5)M(-1) was obtained from UV-vis absorption studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Nanostructured lipid carriers for incorporation of copper(II complexes to be used against Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Sato MR

    2017-03-01

    Full Text Available Mariana R Sato,1 João A Oshiro Junior,1 Rachel TA Machado,1 Paula C de Souza,2 Débora L Campos,2 Fernando R Pavan,2 Patricia B da Silva,1,* Marlus Chorilli1,* 1Department of Drugs and Medicines, Faculdade de Ciências Farmacêuticas, UNESP – Univ Estadual Paulista, Campus Araraquara, Araraquara, SP, Brazil; 2Department of Biological Sciences, Faculdade de Ciências Farmacêuticas, UNESP – Univ Estadual Paulista, Campus Araraquara, Araraquara, SP, Brazil *These authors contributed equally to this work Abstract: Tuberculosis (TB is a disease caused by Mycobacterium tuberculosis. Cessation of treatment before the recommended conclusion may lead to the emergence of multidrug-resistant strains. The aim of this study was to develop nanostructured lipid carriers (NLCs for use in the treatment of M. tuberculosis. The NLCs comprised the following lipid phase: 2.07% polyoxyethylene 40 stearate, 2.05% caprylic/capric triglyceride, and 0.88% polyoxyl 40 hydrogenated castor oil; the following aqueous phase: 3.50% poloxamer 407 (F1–F6, and 0.50% cetyltrimethylammonium bromide (F7–F12; and incorporated the copper(II complexes [CuCl2(INH2]·H2O (1, [Cu(NCS2(INH2]·5H2O (2, and [Cu(NCO2(INH2]·4H2O (3 to form compounds F11.1, F11.2, and F11.3, respectively. The mean diameter of F11, F11.1, F11.2, and F11.3 ranged from 111.27±21.86 to 134.25±22.72 nm, 90.27±12.97 to 116.46±9.17 nm, 112.4±10.22 to 149.3±15.82 nm, and 78.65±6.00 to 122.00±8.70 nm, respectively. The polydispersity index values for the NLCs ranged from 0.13±0.01 to 0.30±0.09. The NLCs showed significant changes in zeta potential, except for F11.2, with F11, F11.1, F11.2, and F11.3 ranging from 18.87±4.04 to 23.25±1.13 mV, 17.03±1.77 to 21.42±1.87 mV, 20.51±1.88 to 22.60±3.44 mV, and 17.80±1.96 to 25.25±7.78 mV, respectively. Atomic force microscopy confirmed the formation of nanoscale spherical particle dispersions by the NLCs. Differential scanning calorimetry determined

  20. Mechanisms of DNA cleavage by copper complexes of 3-Clip-Phen and of its conjugate with a distamycin analogue

    OpenAIRE

    Pitié, Marguerite; Burrows, Cynthia J.; Meunier, Bernard

    2000-01-01

    Mechanisms of DNA oxidation by copper complexes of 3-Clip-Phen and its conjugate with a distamycin analogue, in the presence of a reductant and air, were studied. Characterisation of the production of 5-methylenefuranone (5-MF) and furfural, associated with the release of nucleobases, indicated that these copper complexes oxidised the C1′ and C5′ positions of 2-deoxyribose, respectively, which are accessible from the DNA minor groove. Oxidation at C1′ was the major degradation route. Digestio...

  1. Synthesis, characterization, DNA-binding and cleavage studies of polypyridyl copper(II) complexes

    Science.gov (United States)

    Gubendran, Ammavasi; Rajesh, Jegathalaprathaban; Anitha, Kandasamy; Athappan, Periyakaruppan

    2014-10-01

    Six new mixed-ligand copper(II) complexes were synthesized namely [Cu(phen)2OAc]ClO4ṡH2O(1), [Cu(bpy)2OAc]ClO4ṡH2O(2), [Cu(o-ampacac)(phen)]ClO4(3), [Cu(o-ampbzac)(phen)]ClO4(4), [Cu(o-ampacac)(bpy)]ClO4(5), and [Cu(o-ampbzac)(bpy)]ClO4(6) (phen = 1,10-phenanthroline, bpy = 2, 2‧-bipyridine, o-ampacac = (Z)-4-(2-hydroxylamino)pent-3-ene-2-one,o-ampbzac = (Z)-4-(2-hydroxylamino)-4-phenylbut-3-ene-2-one)and characterized by UV-Vis, IR, EPR and cyclic voltammetry. Ligands were characterized by NMR spectra. Single crystal X-ray studies of the complex 1 shows Cu(II) ions are located in a highly distorted octahedral environment. Absorption spectral studies reveal that the complexes 1-6 exhibit hypochromicity during the interaction with DNA and binding constant values derived from spectral and electrochemical studies indicate that complexes 1, 2 and 3 bind strongly with DNA possibly by an intercalative mode. Electrochemical studies reveal that the complexes 1-4 prefer to bind with DNA in Cu(I) rather than Cu(II) form. The shift in the formal potentials E1/2 and CD spectral studies suggest groove or electrostatic binding mode for the complexes 4-6. Complex 1 can cleave supercoiled (SC) pUC18 DNA efficiently into nicked form II under photolytic conditions and into an open circular form (form II) and linear form (form III) in the presence of H2O2 at pH 8.0 and 37 °C, while the complex 2 does not cleave DNA under similar conditions.

  2. Assessment of serum copper, iron and immune complexes in potentially malignant disorders and oral cancer

    Directory of Open Access Journals (Sweden)

    Ritu TIWARI

    Full Text Available Abstract Potentially malignant disorders (PMDs of oral cavity and oral cancer remain a cause of serious concern despite intensive research and development. Diet and immunity have been identified to play a crucial role as modifying factors in these diseases. Our study intended to explore this relationship by estimating and comparing the serum levels of copper, iron and circulating immune complexes (CICs in patients diagnosed with PMDs and oral cancer and normal healthy individuals. In this study, 40 histopathologically diagnosed cases of PMDs and oral cancer were included along with 30 healthy controls and 5 ml of venous blood was drawn using venipuncture. Serum estimation of copper, iron and CIC then followed using the colorimetric and spectrophotometric methods. The data obtained was subjected to statistical analysis using one way ANOVA and Pearson’s Product-Moment Correlation Test. The mean serum copper level was measured as 138.98 ± 10.13µg/100ml in the PMD group and 141.99 ± 21.44 µg/100ml in the oral cancer as compared to 105.5 + 18.81µ/100ml in the controls. The mean serum CIC levels was highest in the oral cancer (9.65 ± 0.16OD470 followed by the PMD group (0.18 + 0.21 OD470 and least in the control group (0.048 ± 0.02OD470. Whereas, the serum levels of iron showed a significant decrease in the PMD group (110.9 ± 10.54 µg/100ml and the oral cancer group (114.29 ± 25.83 µg/100ml as compared with the control group (136.85 ± 14.48 µg/100ml. There was no positive correlation obtained between the three groups with respect to the chosen parameters indicating that the variables were independent of each other. It can be thus be ascertained that trace elements like copper and iron as well as humoral responses (CICs have a close relationship with PMDs and oral cancers.

  3. Ternary copper(II) complexes with amino acid chains and heterocyclic bases: DNA binding, cytotoxic and cell apoptosis induction properties.

    Science.gov (United States)

    Ma, Tieliang; Xu, Jun; Wang, Yuan; Yu, Hao; Yang, Yong; Liu, Yang; Ding, Weiliang; Zhu, Wenjiao; Chen, Ruhua; Ge, Zhijun; Tan, Yongfei; Jia, Lei; Zhu, Taofeng

    2015-03-01

    Nowadays, chemotherapy is a common means of oncology. However, it is difficult to find excellent chemotherapy drugs. Here we reported three new ternary copper(II) complexes which have potential chemotherapy characteristics with reduced Schiff base ligand and heterocyclic bases (TBHP), [Cu(phen)(TBHP)]H2O (1), [Cu(dpz)(TBHP)]H2O (2) and [Cu(dppz)(TBHP)]H2O (3) (phen=1,10-phenanthroline, dpz=dipyrido [3,2:2',3'-f]quinoxaline, dppz=dipyrido [3,2-a:2',3'-c]phenazine, H2TBHP=2-(3,5-di-tert-butyl-2-hydroxybenzylamino)-2-benzyl-acetic acid). The DNA-binding properties of the complexes were investigated by spectrometric titrations, ethidium bromide displacement experiments and viscosity measurements. The results indicated that the three complexes, especially the complex 13, can strongly bind to calf-thymus DNA (CT-DNA). The intrinsic binding constants Kb of the ternary copper(II) complexes with CT-DNA were 1.37×10(5), 1.81×10(5) and 3.21×10(5) for 1, 2 and 3 respectively. Comparative cytotoxic activities of the copper(II) complexes were also determined by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that the ternary copper(II) complexes had significant cytotoxic activity against the human lung cancer (A549), human esophageal cancer (Eca109) and human gastric cancer (SGC7901) cell lines. Cell apoptosis were detected by AnnexinV/PI flow cytometry and by Western blotting with the protein expression of p53, Bax and Bcl-2. All the three copper complexes can effectively induce apoptosis of the three human tumor cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Synthesis, structures and properties of three copper complexes with dibutyldithiocarbamate ligand

    Science.gov (United States)

    Wang, Chen; Niu, Jiao; Li, Jun; Ma, Xiaoxun

    2017-05-01

    Three copper complexes constructed with sulfur-containing dibutyldithiocarbamate ligand (DDTC), [(Et2NCS2)4Cu2] (1), [(Et2NCS2)(EtO)Cu]2 (2) and [(Et2NCS2)6Cu13I10]n (3) have been synthesized through the reaction of CuI with different mole ratios of DDTC under solution-diffusion conditions. The single crystal X-ray diffraction revealed that divalent Cu cations in complexes 1 and 2 imply that the reactant, Cu(I), was involved in the redox process. They formed binuclear complexes according to bridging S from DDTC ligands and O atoms from ethanol molecules respectively. The mixed valence Cu cations had two types of coordination environments in complex 3 and formed a two-dimensional layered coordination polymer by bridging the five-core Cu(I) clusters and Cu(II). The powder X-ray diffraction, luminescent, thermogravimetric analysis, etc. were also studied in this paper.

  5. Synthesis, characterization and DNA interaction of new copper(II) complexes of Schiff base-aroylhydrazones bearing naphthalene ring.

    Science.gov (United States)

    Gökçe, Cansu; Gup, Ramazan

    2013-05-05

    Two new copper(II) complexes with the condensation products of methyl 2-naphthyl ketone with 4-hydroxybenzohydrazide, 4-hydroxy-N'-[(1Z)-1-(naphthalen-2-yl)ethylidene]benzohydrazide [HL(1)] and (Z)-ethyl 2-(4-(2-(1-(naphthalen-2-yl)ethylidene)hydrazinecarbonyl)phenoxy)acetate (HL(2)) were synthesized and characterized by elemental analysis, infrared spectra, UV-Vis electronic absorption spectra, magnetic susceptibility measurements, TGA, powder XRD and SEM-EDS. The binding properties of the copper(II) complexes with calf thymus DNA were studied by using the absorption titration method. DNA cleavage activities of the synthesized copper complexes were examined by using agarose gel electrophoresis. The effect of complex concentration on the DNA cleavage reactions in the absence and presence of H2O2 was also investigated. The experimental results suggest that the copper complexes bind significantly to calf thymus DNA by both groove binding and intercalation modes and cleavage effectively pBR322 DNA. The mechanistic studies demonstrate that a hydrogen peroxide-derived species and singlet oxygen ((1)O2) are the active oxidative species for DNA cleavage. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Fabrication of Chitosan-complexed Electrode and Evaluation of Its Efficiency in Removal of Copper Ion from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Yoon Young-Chan

    2016-01-01

    Full Text Available In this study, we fabricated chitosan/PVA/activated carbon complexed electrode to remove copper ion from aqueous solution. The prepared composite electrode was analyzed by BET and SEM to investigate its physicochemical properties. Electrochemical properties of prepared composite electrodes were analyzed via cyclic voltammetry. Adsorption performance of copper ion on chitosan composite complexed electrodes was evaluated. Almost similar pore size distribution results were observed in the series of ACP not included electrodes while observed differences in pore size distribution for the ACP included one. Cyclic voltammetry results exhibited that oxidation-reduction reaction does not occur in a potential range of -1.0 ~ 1.0 V. The amount of copper ion during adsroption reaction is increase according to increase of adsorption potential to 1.0 V.

  7. Structural variety and magnetic properties of oxime-bridged copper(II) complexes

    Science.gov (United States)

    Hołyńska, Małgorzata

    2015-10-01

    A series of new oxime-bridged copper(II) complexes is introduced with phenyl 2-pyridyl ketoxime (ppkoH) as a ligand: polymeric [Cu2(ppko)2(ppkoH)2](NO3)(BF4)·CH3OH (1), dinuclear [Cu2(ppko)2(ppkoH)2](ClO4)2 (2), [Cu2(ppko)2(ppkoH)](ClO4)2·0.75CH3OH (3), trinuclear [Cu3(OH)(ppko)3(CH3OH)]·[Cu3(OH)(ppko)3(CH3OH)2](ClO4)4·CH3OH (4) and [Cu3(OH)(ppko)3(CH3OH)](BF4)(NO3) (5). Structural aspects are described in detail, other characterization techniques include elemental analyses, IR and EDX spectra.

  8. Computational Molecular Nanoscience Study of the Properties of Copper Complexes for Dye-Sensitized Solar Cells

    Science.gov (United States)

    Baldenebro-López, Jesús; Castorena-González, José; Flores-Holguín, Norma; Almaral-Sánchez, Jorge; Glossman-Mitnik, Daniel

    2012-01-01

    In this work, we studied a copper complex-based dye, which is proposed for potential photovoltaic applications and is named Cu (I) biquinoline dye. Results of electron affinities and ionization potentials have been used for the correlation between different levels of calculation used in this study, which are based on The Density Functional Theory (DFT) and time-dependent (TD) DFT. Further, the maximum absorption wavelengths of our theoretical calculations were compared with the experimental data. It was found that the M06/LANL2DZ + DZVP level of calculation provides the best approximation. This level of calculation was used to find the optimized molecular structure and to predict the main molecular vibrations, the molecular orbitals energies, dipole moment, isotropic polarizability and the chemical reactivity parameters that arise from Conceptual DFT. PMID:23443107

  9. Computational Molecular Nanoscience Study of the Properties of Copper Complexes for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Jorge Almaral-Sánchez

    2012-11-01

    Full Text Available In this work, we studied a copper complex-based dye, which is proposed for potential photovoltaic applications and is named Cu (I biquinoline dye. Results of electron affinities and ionization potentials have been used for the correlation between different levels of calculation used in this study, which are based on The Density Functional Theory (DFT and time-dependent (TD DFT. Further, the maximum absorption wavelengths of our theoretical calculations were compared with the experimental data. It was found that the M06/LANL2DZ + DZVP level of calculation provides the best approximation. This level of calculation was used to find the optimized molecular structure and to predict the main molecular vibrations, the molecular orbitals energies, dipole moment, isotropic polarizability and the chemical reactivity parameters that arise from Conceptual DFT.

  10. Synthesis, characterization, antibacterial activity, SOD mimic and interaction with DNA of drug based copper(II) complexes

    Science.gov (United States)

    Patel, Mohan N.; Dosi, Promise A.; Bhatt, Bhupesh S.; Thakkar, Vasudev R.

    2011-02-01

    Novel metal complexes of the second-generation quinolone antibacterial agent enrofloxacin with copper(II) and neutral bidentate ligands have been prepared and characterized with elemental analysis reflectance, IR and mass spectroscopy. Complexes have been screened for their in-vitro antibacterial activity against two Gram (+ve)Staphylococcus aureus, Bacillus subtilis, and three Gram (-ve)Serratia marcescens, Escherichia coli and Pseudomonas aeruginosa organisms using the double dilution technique. The binding of this complex with CT-DNA has been investigated by absorption titration, salt effect and viscosity measurements. Binding constant is ranging from 1.3 × 10 4-3.7 × 10 4. The cleavage ability of complexes has been assessed by gel electrophoresis using pUC19 DNA. The catalytic activity of the copper(II) complexes towards the superoxide anion (O 2rad -) dismutation was assayed by their ability to inhibit the reduction of nitroblue tetrazolium (NBT).

  11. Characterisation of the interactions between substrate, copper(II) complex and DNA and their role in rate acceleration in DNA-based asymmetric catalysis

    NARCIS (Netherlands)

    Draksharapu, Apparao; Boersma, Arnold J; Browne, Wesley R; Roelfes, Gerard

    2015-01-01

    Interactions of the azachalcone derived substrate Aza with copper(II) complexes in the presence and absence of st-DNA were studied in detail by UV/Vis absorption, EPR and Raman and (UV and vis) resonance Raman spectroscopies. The binding of Aza to the Lewis acidic copper(II) complexes, which results

  12. Copper(II) complexes of a hexadentate mixed-donor N3S3 macrobicyclic cage: facile rearrangements and interconversions.

    Science.gov (United States)

    Bell, Craig A; Bernhardt, Paul V; Gahan, Lawrence R; Martínez, Manuel; Monteiro, Michael J; Rodríguez, Carlos; Sharrad, Clint A

    2010-03-08

    The potentially hexadentate mixed-donor cage ligand 1-methyl-8-amino-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]eicosane (AMME-N(3)S(3)sar; sar=sarcophagine) displays variable coordination modes in a complex with copper(II). In the absence of coordinating anions, the ligand adopts a conventional hexadentate N(3)S(3) binding mode in the complex [Cu(AMME-N(3)S(3)sar)](ClO(4))(2) that is typical of cage ligands. This structure was determined by X-ray crystallography and solution spectroscopy (EPR and NIR UV/Vis). However, in the presence of bromide ions in DMSO, clean conversion to a five-coordinate bromido complex [Cu(AMME-N(3)S(3)sar)Br](+) is observed that features a novel tetradentate (N(2)S(2))-coordinated form of the cage ligand. This copper(II) complex has also been characterized by X-ray crystallography and solution spectroscopy. The mechanism of the reversible interconversion between the six- and five-coordinated copper(II) complexes has been studied and the reaction has been resolved into two steps; the rate of the first is linearly dependent on bromide ion concentration and the second is bromide independent. Electrochemistry of both [Cu(AMME-N(3)S(3)sar)](2+) and [Cu(AMME-N(3)S(3)sar)Br](+) in DMSO shows that upon reduction to the monovalent state, they share a common five-coordinated form in which the ligand is bound to copper in a tetradentate form exclusively, regardless of whether a six- or five-coordinated copper(II) complex is the precursor.

  13. Calorimetric study on complexation of copper(II) ion with some amide solvents in acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Kenta [Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Endoh, Toshihiko [Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto 390-8621 (Japan); Yokoi, Masatoki [Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto 390-8621 (Japan); Umebayashi, Yasuhiro [Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Ishiguro, Shin-Ichi [Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)]. E-mail: analsscc@mbox.nc.kyushu-u.ac.jp

    2005-06-15

    Complexation of copper(II) ion with some amide solvents such as N-methylformamide (NMF), formamide (FA), N,N-dimethylacetamide (DMA) and N-methylacetamide (NMA) has been studied by titration calorimetry in acetonitrile containing 0.1 mol dm{sup -3} (C{sub 2}H{sub 5}){sub 4}ClO{sub 4} as an ionic medium at 298 K. These amides coordinate to the metal ion to form a series of mononuclear complexes, and their formation constants, enthalpies and entropies have been obtained. Thermodynamic parameters of formation of Cu(NMF){sup 2+} and Cu(FA){sup 2+} are not significantly different from those of Cu(DMF){sup 2+} (DMF: N,N-dimethylformamide), implying that a strong hydrogen-bonded structure of liquid NMF and FA are practically ruptured in the acetonitrile solution examined. The formation of Cu(DMA){sup 2+} and Cu(NMA){sup 2+} are appreciably less exothermic than the respective formation of Cu(DMF){sup 2+} and Cu(NMF){sup 2+} complexes, implying that the presence of the acetyl group causes steric hindrance upon its coordination to the metal ion.

  14. Synthesis and Characterization of Novel Thiourea Derivatives and Their Nickel and Copper Complexes

    Directory of Open Access Journals (Sweden)

    Gün Binzet

    2013-01-01

    Full Text Available New benzoyl thiourea derivatives and their nickel and copper complexes were synthesized. The structure of the synthesized compounds were confirmed by elemental analysis, FT-IR, and 1H NMR techniques. Four of the synthesized compounds are analyzed by X-ray single crystal diffraction technique. Whereas N,N-dimethyl-N′-(4-fluorobenzoylthiourea, N,N-diethyl-N′-(4-fluorobenzoylthiourea, and N,N-di-n-butyl-N′-(4-fluorobenzoyl thiourea crystallize in the monoclinic system, bis(N,N-di-n-propyl-N′-(4-fluorobenzoylthioureato nickel(II complex crystallizes in the triclinic system. These ligand molecules form dimers through strong intermolecular hydrogen bonds such as N–H⋯S, C–H⋯O, and N–H⋯O. Moreover, there are different types of intramolecular interactions in the crystal structures. Bis(N,N-dimethyl-N′-(4-fluorobenzoylthioureato nickel(II complex has a nearly square-planar coordination. The distance of nickel atom from the best plane through the coordination sphere is 0.029 Å.

  15. Synthesis, crystal structure and reactivity of copper(II) complexes of tetradentate N2S2 donor ligands

    Science.gov (United States)

    Sarkar, Sandipan; Paul, Hena; Drew, Michael G. B.; Zangrando, Ennio; Chattopadhyay, Pabitra

    2009-09-01

    Two new hexa-coordinated mononuclear copper(II) complexes of two ligands L 1 and L 2 containing NSSN donor sets formulated as [Cu(L)(H 2O) 2](NO 3) 2 [ 1a, L = 1,2-bis(2-pyridylmethylthio)ethane (L 1), 1b L = 1,3-bis(2-pyridyl-methylthio)propane (L 2)] were synthesized and characterized by physico-chemical and spectroscopic methods. In 1a the single crystal X-ray crystallography analysis showed a distorted octahedral geometry about copper(II) ion. The crystal packing evidences pairs of complexes arranged about a center of symmetry and connected through a H-bond occurring between aquo ligands and nitrate anions. On reaction with chloride and pseudohalides (N 3- and SCN -), in acetonitrile at ambient temperature, complexes 1 changed to monocationic penta-coordinated mononuclear copper(II) species formulated as [Cu(L)(Cl)]NO 3 ( 2), [Cu(L)(N 3)]NO 3 ( 3), and [Cu(L)(SCN)]NO 3 ( 4). These copper(II) complexes have been isolated in pure form from the reaction mixtures and characterized by physico-chemical and spectroscopic tools. The solid-state structure of 2a, established by X-ray crystallography, shows a trigonal bipyramidal geometry about the metal ion with a trigonality index ( τ) of 0.561.

  16. L-glutamine Schiff base copper complex as a proteasome inhibitor and an apoptosis inducer in human cancer cells.

    Science.gov (United States)

    Xiao, Yan; Bi, Caifeng; Fan, Yuhua; Cui, Cindy; Zhang, Xia; Dou, Q Ping

    2008-11-01

    Interest in the use of metallic compounds for cancer treatment has been increasing since the discovery of cisplatin. Clinical studies suggest the use of proteasome inhibitors as potential novel anticancer agents. L-glutamine is the most abundant free amino acid in the body, and has been shown to play a regulatory role in several cellular processes, including metabolism, degradation, redox potential and cellular integrity. Although glutamine is reported to play a role in the regulation of apoptosis, the effect of glutamine copper complex on tumor cells and the involved molecular mechanism have not been investigated. Here, for the first time, we report that a newly synthesized L-glutamine-containing copper complex has proteasome-inhibitory activity in human breast cancer and leukemia cells. The inhibition of the tumor proteasomal activity results in the accumulation of ubiquitinated proteins and ubiquitinated form of IkappaB-alpha, a natural proteasome substrate, followed by induction of apoptosis. Furthermore, this glutamine Schiff base copper complex selectively inhibits the proteasomal activity and induces cell death in cultured breast cancer cells, but not normal, immortalized breast cells. Our data suggest that glutamine Schiff base copper complexes have a potential use for to be used in cancer treatment and prevention.

  17. Femtomole level photoelectrochemical aptasensing for mercury ions using quercetin-copper(II) complex as the DNA intercalator.

    Science.gov (United States)

    Li, Hongbo; Xue, Yan; Wang, Wei

    2014-04-15

    An ultrasensitive and selective photoelectrochemical (PEC) aptasensor for mercury ions was first fabricated based on perylene-3, 4, 9, 10-tetracarboxylic acid/graphene oxide (PTCA/GO) heterojunction using quercetin-copper(II) complex intercalated into the poly(dT)-poly(dA) duplexes. Both the PTCA/GO heterojunction and the quercetin-copper(II) complex are in favor of the sensitivity for the fabricated PEC aptasensor due to band alignment and strong reduction capability, respectively. And they efficiently promote the separation of photoexcited carriers and enhance the photocurrent. The formation of thymine-Hg(2+)-thymine coordination chemistry resulted in the dehybridization of poly(dT)-poly(dA) duplexes and then the intercalator quercetin-copper(II) complex broke away from the surface of the PEC aptasensor. As the concentration of mercury ions increased, the photocurrent gradually decreased. The electrode response for mercury ions detection was in the linear range from 0.01 pmol L(-1) to 1.00 pmol L(-1) with the detection limit of 3.33 fmol L(-1). The label-free PEC aptasensor has excellent performances with ultrasensitivity and good selectivity besides the advantage of economic and facile fabrication. The strategy of quercetin-copper(II) complex as a novel DNA intercalator paves a new way to improve the performances for PEC sensors. © 2013 Published by Elsevier B.V.

  18. Neutral copper-phosphido-borane complexes: synthesis, characterization, and use as precatalysts in C(sp)-P bond formation.

    Science.gov (United States)

    Abdellah, Ibrahim; Bernoud, Elise; Lohier, Jean-François; Alayrac, Carole; Toupet, Loïc; Lepetit, Christine; Gaumont, Annie-Claude

    2012-04-28

    Copper-phosphido-borane complexes were synthesized and isolated for the first time. Their structures were experimentally and computationally investigated. They were shown to display catalytic activity in C(sp)-P bond formation. This journal is © The Royal Society of Chemistry 2012

  19. Physico-chemical characterization and anti- microbial activity of copper(II complexes with 2-amino and 2-methylbenzimidazole derivatives

    Directory of Open Access Journals (Sweden)

    Podunavac-Kuzmanović Sanja O.

    2004-01-01

    Full Text Available Copper(II chloride, in warm ethanolic solution, reacted with 2-amino and 2-methylbenzimidazole derivatives to give complexes of the formula CuL2Cl2·nH2O, where L=1-benzyl-2-aminobenzimidazole 1-(4-methylbenzyl-2-aminobenzimidazole, 1-benzyl-2-methylbenzimidazole and 1-(4-methylbenzyl-2-methylbenzimidazole( n=1 or 2. The complexes were characterized by elemental analysis of the metal, molar conductivity magnetic susceptibility measurements and IR spectra. The molar conductivities of copper(IIcomplexes in dimethyl formamide (DMF corresponding to a 1:1 type of electrolyte indicate that in all the complexes one of the coordinated chloride ions has been replaced by DMF molecule. The room temperature effective magnetic moments and IR data of the complexes suggest that all Cu(II complexes have a tetrahedral configuration, which is realized by participation of the pyridine nitrogen of two organic ligand molecules and two chloride anions. The antimicrobial activity of the ligands and their complexes against Pseudomonas aeruginosa, Bacillus sp. Staphylococcus aureus, Sarcina lutea and Saccharomyces cerevisiae was investigated. The effect of copper complexation on the ligand antimicrobial activity is discussed.

  20. Production of Copper as a Complex Mining and Metallurgical Processing System in Polish Copper Mines of the Legnica-Glogów Copper Belt

    Science.gov (United States)

    Malewski, Jerzy

    2017-12-01

    Geological and technological conditions of Cu production in the Polish copper mines of the Legnica-Glogów Copper Belt are presented. Cu production is recognized as a technological fractal consisting of subsystems for mineral exploration, ore extraction and processing, and metallurgical treatment. Qualitative and quantitative models of these operations have been proposed, including estimation of their costs of process production. Numerical calculations of such a system have been performed, which allow optimize the system parameters according to economic criteria under variable Cu mineralization in the ore deposit. The main objective of the study is to develop forecasting tool for analysis of production efficiency in domestic copper mines based on available sources of information. Such analyses are primarily of social value, allowing for assessment of the efficiency of management of local mineral resources in the light of current technological and market constraints. At the same time, this is a concept of the system analysis method to manage deposit exploitation on operational and strategic level.

  1. Anticancer Activity of Copper Complex of (4R)-(-)-2-Thioxo-4-thiazolidinecarboxylic Acid and 3-Rhodaninepropionic Acid on Prostate and Breast Cancer Cells by Fluorescent Microscopic Imaging.

    Science.gov (United States)

    Xie, Fang; Peng, Fangyu

    2017-09-09

    Copper complexes with strong anticancer activity are promising new drugs for treatment of patients with metastatic cancer. Copper 8-hydroxyquinoline-2-carboxaldehyde-thiosemicarbazide (CuHQTS) and copper 8-hydroxyquinoline-2-carboxaldehyde-4,4-dimethyl-3-thiosemicarbazide (CuHQDMTS) were found to have strong anticancer activity against cisplatin-resistant neuroblastoma cells and prostate cancer cells. This study aimed to synthesize and characterize two new anticancer copper complexes, copper complex of (4R)-(-)-2-Thioxo-4-thiazolidinecarboxylic acid (CuTTDC), and copper complex of 3-Rhodaninepropionic acid-copper complex (CuRDPA). Cell growth inhibition and cytotoxicity of CuTTDC and CuRDPA on prostate and breast cancer cells were evaluated with Cell Counting Kits-8 (CCK8) assay and fluorescent microscopic imaging respectively. Strong anticancer activity of CuTTDC and CuRDPA was demonstrated by growth inhibition and cytotoxicity of prostate and breast cancer cells treated with these two copper complexes, supporting further investigation of potential use of these two new anticancer complexes for treatment of prostate and breast cancer metastasis.

  2. Optimizing the Readout of Lanthanide-DOTA Complexes for the Detection of Ligand-Bound Copper(I

    Directory of Open Access Journals (Sweden)

    Jill R. Hanna

    2017-05-01

    Full Text Available The CuAAC ‘click’ reaction was used to couple alkyne-functionalized lanthanide-DOTA complexes to a range of fluorescent antennae. Screening of the antenna components was aided by comparison of the luminescent output of the resultant sensors using data normalized to account for reaction conversion as assessed by IR. A maximum 82-fold enhanced signal:background luminescence output was achieved using a Eu(III-DOTA complex coupled to a coumarin-azide, in a reaction which is specific to the presence of copper(I. This optimized complex provides a new lead design for lanthanide-DOTA complexes which can act as irreversible ‘turn-on’ catalytic sensors for the detection of ligand-bound copper(I.

  3. Tetranuclear 3d/4f coordination clusters as highly efficient catalysts for Friedel Crafts alkylation

    OpenAIRE

    Griffiths, Kieran; Kumar, Prashant; Akien, Geoffrey R.; Chilton, Nicholas F; Abdul-Sada, Alaa; Tizzard, Graham J; Simon J. Coles; Kostakis, George E.

    2016-01-01

    A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel-Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic system...

  4. Tetranuclear Zn/4f coordination clusters as highly efficient catalysts for Friedel–Crafts alkylation

    OpenAIRE

    Griffiths, Kieran; Kumar, Prashant; Akien, Geoffrey R.; Chilton, Nicholas F; Abdul-Sada, Alaa; Tizzard, Graham; Coles, Simon; Kostakis, George E.

    2016-01-01

    A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel–Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic system...

  5. Synthesis, Crystal Structure, Spectroscopic Properties and Potential Biological Activities of Salicylate‒Neocuproine Ternary Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Lenka Kucková

    2015-01-01

    Full Text Available Mixed ligand copper(II complexes containing derivatives of salicylic acid and heterocyclic ligands with nitrogen donor atoms have been the subject of various studies and reviews. In this paper, synthesis and characterization of the ternary copper(II complexes of neocuproine (2,9-dimethyl-1,10-phenanthroline, Neo and salicylate ligands (Sal are reported. In addition, the crystal structures of ([Cu(H2O(5-Cl-Sal(Neo] (1, [Cu(μ-Sal(Neo]2 (2, Cu2(μ-5-Cl-Sal(5-Cl-HSal2(Neo2]·EtOH (3 were determined. In order to compare structural and biological properties of the prepared complexes, spectroscopic and biological studies were performed. Results of X-ray diffraction show that prepared complexes form three types of crystal structures in a given system: monomeric, dimeric and dinuclear complex. The preliminary study on the DNA cleavage activity has shown that the complexes under study behave as the chemical nucleases in the presence of added hydrogen peroxide with slight differences in the activity (1 > 2 > 3. The complexes 1 and 2 exhibited nuclease activity itself indicating the interaction of complexes with the DNA. It has been proposed that the enhanced destructive effect of the complexes 1 and 2 on the DNA is a result of two possible mechanisms of action: (i the conversion of closed circular DNA (form I to the nicked DNA (form II caused by the copper complex itself and (ii damage of DNA by Reactive Oxygen Species (ROS—products of the interaction of copper with hydrogen peroxide by means of Fenton reaction (hydroxyl radicals. Thus the biological activity of the prepared Cu(II complexes containing derivatives of salicylic acid and phenanthroline molecules is substantiated by two independent mechanisms. While derivatives of salicylic acids in the coordination sphere of copper complexes are responsible for radical-scavenging activity (predominantly towards superoxide radical anion, the presence of chelating ligand 2,9-dimethyl-1,10-phenanthroline

  6. Synthesis, characterization, electrochemical studies and DFT calculations of amino acids ternary complexes of copper (II) with isonitrosoacetophenone. Biological activities

    Science.gov (United States)

    Tidjani-Rahmouni, Nabila; Bensiradj, Nour el Houda; Djebbar, Safia; Benali-Baitich, Ouassini

    2014-10-01

    Three mixed complexes having formula [Cu(INAP)L(H2O)2] where INAP = deprotonated isonitrosoacetophenone and L = deprotonated amino acid such as histidine, phenylalanine and tryptophan have been synthesized. They have also been characterized using elemental analyses, molar conductance, UV-Vis, IR and ESR spectra. The value of molar conductance indicates them to be non-electrolytes. The spectral studies support the binding of the ligands with two N and two O donor sites to the copper (II) ion, giving an arrangement of N2O2 donor groups. Density Functional Theory (DFT) calculations were applied to evaluate the cis and trans coordination modes of the two water molecules. The trans form was shown to be energetically more stable than the cis one. The ESR data indicate that the covalent character of the metal-ligand bonding in the copper (II) complexes increases on going from histidine to phenylalanine to tryptophan. The electrochemical behavior of the copper (II) complexes was determined by cyclic voltammetry which shows that the chelate structure and electron donating effects of the ligands substituent are among the factors influencing the redox potentials of the complexes. The antimicrobial activities of the complexes were evaluated against several pathogenic microorganisms to assess their antimicrobial potentials. The copper complexes were found to be more active against Gram-positive than Gram-negative bacteria. Furthermore, the antioxidant efficiencies of the metal complexes were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The antioxidant activity of the complexes indicates their moderate scavenging activity against the radical DPPH.

  7. Spectroscopic studies on copper(II) halide complexes with isomeric benzoylpyridines: Electronic and electron spin resonance spectral evidence for five-coordinate copper(II) species in solution

    Science.gov (United States)

    Ahuja, I. S.; Tripathi, Shailendra

    1992-05-01

    Coordination compounds formed by copper(II) chloride and bromide with 2-, 3- and 4-benzoylpyridines (BOP)Cu(2-BOP)Cl 2, Cu(3-BOP) 2Cl 2, Cu(4-BOP)Cl 2, Cu(2-BOP) 2Br 2, Cu(3-BOP) 2Br 2 and Cu(4-BOP) 2Br 2—have been characterized by elemental analyses, molar conductance, magnetic moments, electronic, IR and ESR spectral studies. It is suggested that Cu(2-BOP)Cl 2 is monomeric tetrahedral, Cu(3-BOP) 2Cl 2 and Cu(4-BOP)Cl 2 are dimeric octahedral and tetrahedral structures, respectively, bridging through chlorines while all the bromo complexes are polymeric octahedral structures with bridging bromine atoms in the solid state. Powder ESR data reveal rhombic symmetry for all the chloro complexes. Cu(2-BOP) 2Br 2 is suggested to have an axial symmetry while the other bromo complexes are isotropic in nature. Electronic and ESR spectral studies in DMSO solution suggest the interaction of solvent molecules with copper(II) ions in the axial plane. The solution spectral data are almost comparable suggesting same local symmetry for all the compounds consistent with five-coordinate square pyramidal geometry in each case. ESR spectra also suggest considerable CuCu interactions in Cu(3-BOP) 2Cl 2. Various Spin—Hamiltonian parameters calculated from ESR data indicate the presence of an unpaired electron in the d x2- y2 orbital of the copper(II) ion in an axial symmetry.

  8. Diagnosis of abnormal biliary copper excretion by positron emission tomography with targeting of (64)Copper-asialofetuin complex in LEC rat model of Wilson's disease.

    Science.gov (United States)

    Bahde, Ralf; Kapoor, Sorabh; Bhargava, Kuldeep K; Palestro, Christopher J; Gupta, Sanjeev

    2014-01-01

    Identification by molecular imaging of key processes in handling of transition state metals, such as copper (Cu), will be of considerable clinical value. For instance, the ability to diagnose Wilson's disease with molecular imaging by identifying copper excretion in an ATP7B-dependent manner will be very significant. To develop highly effective diagnostic approaches, we hypothesized that targeting of radiocopper via the asialoglycoprotein receptor will be appropriate for positron emission tomography, and examined this approach in a rat model of Wilson's disease. After complexing (64)Cu to asialofetuin we studied handling of this complex compared with (64)Cu in healthy LEA rats and diseased homozygous LEC rats lacking ATP7B and exhibiting hepatic copper toxicosis. We analyzed radiotracer clearance from blood, organ uptake, and biliary excretion, including sixty minute dynamic positron emission tomography recordings. In LEA rats, (64)Cu-asialofetuin was better cleared from blood followed by liver uptake and greater biliary excretion than (64)Cu. In LEC rats, (64)Cu-asialofetuin activity cleared even more rapidly from blood followed by greater uptake in liver, but neither (64)Cu-asialofetuin nor (64)Cu appeared in bile. Image analysis demonstrated rapid visualization of liver after (64)Cu-asialofetuin administration followed by decreased liver activity in LEA rats while liver activity progressively increased in LEC rats. Image analysis resolved this difference in hepatic activity within one hour. We concluded that (64)Cu-asialofetuin complex was successfully targeted to the liver and radiocopper was then excreted into bile in an ATP7B-dependent manner. Therefore, hepatic targeting of radiocopper will be appropriate for improving molecular diagnosis and for developing drug/cell/gene therapies in Wilson's disease.

  9. Zinc(II)-Thiosemicarbazone Complexes Are Localized to the Lysosomal Compartment Where They Transmetallate with Copper Ions to Induce Cytotoxicity.

    Science.gov (United States)

    Stacy, Alexandra E; Palanimuthu, Duraippandi; Bernhardt, Paul V; Kalinowski, Danuta S; Jansson, Patric J; Richardson, Des R

    2016-05-26

    As the di-2-pyridylketone thiosemicarbazone (DpT) and 2-acetylpyridine thiosemicarbazone (ApT) series show potent antitumor activity in vitro and in vivo, we synthesized their fluorescent zinc(II) complexes to assess their intracellular distribution. The Zn(II) complexes generally showed significantly greater cytotoxicity than the thiosemicarbazones alone in several tumor cell-types. Notably, specific structure-activity relationships demonstrated the importance of the di-2-pyridyl pharmacophore in their activity. Confocal fluorescence imaging and live cell microscopy showed that the Zn(II) complex of our lead compound, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), which is scheduled to enter clinical trials, was localized to lysosomes. Under lysosomal conditions, the Zn(II) complexes were shown to transmetallate with copper ions, leading to redox-active copper complexes that induced lysosomal membrane permeabilization (LMP) and cytotoxicity. This is the first study to demonstrate direct lysosomal targeting of our novel Zn(II)-thiosemicarbazone complexes that mediate their activity via transmetalation with copper ions and LMP.

  10. In vitro and in vivo anti-inflammatory active copper(II-lawsone complexes.

    Directory of Open Access Journals (Sweden)

    Ján Vančo

    Full Text Available We report in vitro and in vivo anti-inflammatory activities of a series of copper(II-lawsone complexes of the general composition [Cu(Law2(LNx(H2O(2-x]·yH2O; where HLaw = 2-hydroxy-1,4-naphthoquinone, x = 1 when LN = pyridine (1 and 2-aminopyridine (3 and x = 2 when LN = imidazole (2, 3-aminopyridine (4, 4-aminopyridine (5, 3-hydroxypyridine (6, and 3,5-dimethylpyrazole (7. The compounds were thoroughly characterized by physical techniques, including single crystal X-ray analysis of complex 2. Some of the complexes showed the ability to suppress significantly the activation of nuclear factor κB (NF-κB both by lipopolysaccharide (LPS and TNF-alpha (complexes 3-7 at 100 nM level in the similar manner as the reference drug prednisone (at 1 μM level. On the other hand, all the complexes 1-7 decreased significantly the levels of the secreted TNF-alpha after the LPS activation of THP-1 cells, thus showing the anti-inflammatory potential via both NF-κB moderation and by other mechanisms, such as influence on TNF-alpha transcription and/or translation and/or secretion. In addition, a strong intracellular pro-oxidative effect of all the complexes has been found at 100 nM dose in vitro. The ability to suppress the inflammatory response, caused by the subcutaneous application of λ-carrageenan, has been determined by in vivo testing in hind-paw edema model on rats. The most active complexes 1-3 (applied in a dose corresponding to 40 μmol Cu/kg, diminished the formation of edema simalarly as the reference drug indomethacine (applied in 10 mg/kg dose. The overall effect of the complexes, dominantly 1-3, shows similarity to anti-inflammatory drug benoxaprofen, known to induce intracellular pro-oxidative effects.

  11. In vitro and in vivo anti-inflammatory active copper(II)-lawsone complexes.

    Science.gov (United States)

    Vančo, Ján; Trávníček, Zdeněk; Hošek, Jan; Suchý, Pavel

    2017-01-01

    We report in vitro and in vivo anti-inflammatory activities of a series of copper(II)-lawsone complexes of the general composition [Cu(Law)2(LN)x(H2O)(2-x)]·yH2O; where HLaw = 2-hydroxy-1,4-naphthoquinone, x = 1 when LN = pyridine (1) and 2-aminopyridine (3) and x = 2 when LN = imidazole (2), 3-aminopyridine (4), 4-aminopyridine (5), 3-hydroxypyridine (6), and 3,5-dimethylpyrazole (7). The compounds were thoroughly characterized by physical techniques, including single crystal X-ray analysis of complex 2. Some of the complexes showed the ability to suppress significantly the activation of nuclear factor κB (NF-κB) both by lipopolysaccharide (LPS) and TNF-alpha (complexes 3-7 at 100 nM level) in the similar manner as the reference drug prednisone (at 1 μM level). On the other hand, all the complexes 1-7 decreased significantly the levels of the secreted TNF-alpha after the LPS activation of THP-1 cells, thus showing the anti-inflammatory potential via both NF-κB moderation and by other mechanisms, such as influence on TNF-alpha transcription and/or translation and/or secretion. In addition, a strong intracellular pro-oxidative effect of all the complexes has been found at 100 nM dose in vitro. The ability to suppress the inflammatory response, caused by the subcutaneous application of λ-carrageenan, has been determined by in vivo testing in hind-paw edema model on rats. The most active complexes 1-3 (applied in a dose corresponding to 40 μmol Cu/kg), diminished the formation of edema simalarly as the reference drug indomethacine (applied in 10 mg/kg dose). The overall effect of the complexes, dominantly 1-3, shows similarity to anti-inflammatory drug benoxaprofen, known to induce intracellular pro-oxidative effects.

  12. A differential genome-wide transcriptome analysis: impact of cellular copper on complex biological processes like aging and development.

    Directory of Open Access Journals (Sweden)

    Jörg Servos

    Full Text Available The regulation of cellular copper homeostasis is crucial in biology. Impairments lead to severe dysfunctions and are known to affect aging and development. Previously, a loss-of-function mutation in the gene encoding the copper-sensing and copper-regulated transcription factor GRISEA of the filamentous fungus Podospora anserina was reported to lead to cellular copper depletion and a pleiotropic phenotype with hypopigmentation of the mycelium and the ascospores, affected fertility and increased lifespan by approximately 60% when compared to the wild type. This phenotype is linked to a switch from a copper-dependent standard to an alternative respiration leading to both a reduced generation of reactive oxygen species (ROS and of adenosine triphosphate (ATP. We performed a genome-wide comparative transcriptome analysis of a wild-type strain and the copper-depleted grisea mutant. We unambiguously assigned 9,700 sequences of the transcriptome in both strains to the more than 10,600 predicted and annotated open reading frames of the P. anserina genome indicating 90% coverage of the transcriptome. 4,752 of the transcripts differed significantly in abundance with 1,156 transcripts differing at least 3-fold. Selected genes were investigated by qRT-PCR analyses. Apart from this general characterization we analyzed the data with special emphasis on molecular pathways related to the grisea mutation taking advantage of the available complete genomic sequence of P. anserina. This analysis verified but also corrected conclusions from earlier data obtained by single gene analysis, identified new candidates of factors as part of the cellular copper homeostasis system including target genes of transcription factor GRISEA, and provides a rich reference source of quantitative data for further in detail investigations. Overall, the present study demonstrates the importance of systems biology approaches also in cases were mutations in single genes are analyzed to

  13. Immobilized copper(II) macrocyclic complex on MWCNTs with antibacterial activity

    Science.gov (United States)

    Tarlani, Aliakbar; Narimani, Khashayar; Mohammadipanah, Fatemeh; Hamedi, Javad; Tahermansouri, Hasan; Amini, Mostafa M.

    2015-06-01

    In a new approach, a copper(II) tetraaza macrocyclic complex (CuTAM) was covalently bonded on modified multi-walled carbon nanotubes (MWCNTs). To achieve this purpose, MWCNTs were converted to MWCNT-COCl and then reacted to NH groups of TAM ligand. The prepared material was characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), and FESEM (field emission scanning electron microscopy). FT-IR and TGA demonstrated the presence of the organic moieties, and XRD proved that the structure of MWCNTs remained intact during the three modification steps. An increase in the ID/IG ratio in Raman spectra confirmed the surface modifications. Finally, the samples were subjected to an antibacterial assessment to compare their biological activity. The antibacterial test showed that the grafted complex on the surface of the nanotube (MWCNT-CO-CuTAM) has higher antibacterial activity against Bacillus subtilis ATCC 6633 than the MWCNT-COOH and CuTAM with 1000 and 2000 μg/mL.

  14. The Stoichiometry of Isoquercitrin Complex with Iron or Copper Is Highly Dependent on Experimental Conditions.

    Science.gov (United States)

    Catapano, Maria Carmen; Tvrdý, Václav; Karlíčková, Jana; Migkos, Thomas; Valentová, Kateřina; Křen, Vladimír; Mladěnka, Přemysl

    2017-10-30

    Interaction of flavonoids with transition metals can be partially responsible for their impact on humans. Stoichiometry of the iron/copper complex with a flavonoid glycoside isoquercitrin, a frequent component of food supplements, was assessed using competitive and non-competitive methods in four (patho)physiologically-relevant pH values (4.5. 5.5, 6.8, and 7.5). Isoquercitrin chelated all tested ions (Fe 2+ , Fe 3+ , Cu 2+ , and Cu⁺) but its affinity for Cu⁺ ions proved to be very low. In general, the chelation potency dropped with pH lowering. Metal complexes of 1:1 stoichiometry were mostly formed, however, they were not stable and the stoichiometry changed depending on conditions. Isoquercitrin was able to reduce both Cu 2+ and Fe 3+ ions at low ratios, but its reducing potential was diminished at higher ratios (isoquercitrin to metal) due to the metal chelation. In conclusion, this study emphasizes the need of using multiple different methods for the assessment of chelation potential in moderately-active metal chelators, like flavonoids.

  15. The Stoichiometry of Isoquercitrin Complex with Iron or Copper Is Highly Dependent on Experimental Conditions

    Directory of Open Access Journals (Sweden)

    Maria Carmen Catapano

    2017-10-01

    Full Text Available Interaction of flavonoids with transition metals can be partially responsible for their impact on humans. Stoichiometry of the iron/copper complex with a flavonoid glycoside isoquercitrin, a frequent component of food supplements, was assessed using competitive and non-competitive methods in four (pathophysiologically-relevant pH values (4.5. 5.5, 6.8, and 7.5. Isoquercitrin chelated all tested ions (Fe2+, Fe3+, Cu2+, and Cu+ but its affinity for Cu+ ions proved to be very low. In general, the chelation potency dropped with pH lowering. Metal complexes of 1:1 stoichiometry were mostly formed, however, they were not stable and the stoichiometry changed depending on conditions. Isoquercitrin was able to reduce both Cu2+ and Fe3+ ions at low ratios, but its reducing potential was diminished at higher ratios (isoquercitrin to metal due to the metal chelation. In conclusion, this study emphasizes the need of using multiple different methods for the assessment of chelation potential in moderately-active metal chelators, like flavonoids.

  16. Antimony recovery from complex copper concentrates through hydro- and electrometallurgical processes

    OpenAIRE

    Awe, Samuel Ayowole

    2013-01-01

    Today, one of the major difficulties confronted during copper metallurgy is the elimination of antimony and arsenic impurities from the process. This is because the pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of antimony and arsenic. During smelting of copper concentrates, arsenic is easily removed into the offgas while antimony is not readily removed due to its lower partial pressure and high affinity for liquid ...

  17. Synthesis of copper/nickel nanoparticles using newly synthesized Schiff-base metals complexes and their cytotoxicity/catalytic activities.

    Science.gov (United States)

    Aazam, Elham S; El-Said, Waleed Ahmed

    2014-12-01

    Transition metal complexes compounds with Schiff bases ligand representing an important class of compounds that could be used to develop new metal-based anticancer agents and as precursors of metal NPs. Herein, 2,3-bis-[(3-ethoxy-2-hydroxybenzylidene)amino]but-2-enedinitrile Schiff base ligand and its corresponding copper/nickel complexes were synthesized. Also, we reported a facile and rapid method for synthesis nickel/copper nanoparticles based on thermal reduction of their complexes. Free ligand, its metal complexes and metals nanoparticles have been characterized based on elemental analysis, transmission electron microscopy, powder X-ray diffraction, magnetic measurements and by various spectroscopic (UV-vis, FT-IR, (1)H NMR, GC-MS) techniques. Additionally, the in vitro cytotoxic activity of free ligand and its complexes compounds were assessed against two cancer cell lines (HeLa and MCF-7 cells)and one healthy cell line (HEK293 cell). The copper complex was found to be active against these cancer cell lines at very low LD50 than the free ligand, while nickel complex did not show any anticancer activity against these cell lines. Also, the antibacterial activity of as-prepared copper nanoparticles were screened against Escherichia coli, which demonstrated minimum inhibitory concentration and minimum bactericidal concentration values lower than those values of the commercial Cu NPs as well as the previous reported values. Moreover, the synthesized nickel nanoparticles demonstrated remarkable catalytic performance toward hydrogenation of nitrobenzene that producing clean aniline with high selectivity (98%). This reactivity could be attributed to the high degree of dispersion of Ni nanoparticles. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Synthesis, Crystal Structure, Stacking Effect and Antibacterial Studies of a Novel Quaternary Copper (II) Complex with Quinolone

    OpenAIRE

    Longguan Zhu; Xuchun Fu; Guoping Wang; Guangguo Wu

    2003-01-01

    The structural properties of a new copper (II) complex [Cu2(cip)2(bpy)2(pip)]·6H2O (bpy=2,2’-bipyridyl, cip=1-cyclopropyl-6-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, pip= piperazinyl anion), obtained during the synthesis of the copper complex with ciprofloxacin (cpf), has been investigated. The complex crystallizes in the triclinic system, space group P-1. The cell dimensions are: a=6.874(2) Å, b= 10.761(3) Å, c= 17.969(5) Å, α =80.071(6)°, β= 85.253(6)°, γ...

  19. Copper (II)

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: A Schiff base was prepared from the reaction of 2 - amino - 3 – methylbutanoic acid and 2, 4 - pentanedione. The reaction of the prepared Schiff base with ethanolic solution of copper (II) chloride formed diaquo bis( N – 2 – amino – 3 - methylbutyl - 2, 4 - pentanedionato) copper (II) complex. The Schiff base is ...

  20. Cube-type nitrido complexes containing titanium and zinc/copper.

    Science.gov (United States)

    Martín, Avelino; Martínez-Espada, Noelia; Mena, Miguel; Pérez-Redondo, Adrian; Yélamos, Carlos

    2006-08-21

    Several azaheterometallocubane complexes containing [MTi3N4] cores have been prepared by the reaction of [{Ti(eta5-C5Me5)(mu-NH)}3(mu3-N)] (1) with zinc(II) and copper(I) derivatives. The treatment of 1 with zinc dichloride in toluene at room temperature produces the adduct [Cl2Zn{(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)}] (2). Attempts to crystallize 2 in dichloromethane gave yellow crystals of the ammonia adduct [(H3N)Cl2Zn{(mu3-NH)Ti3(eta5-C5Me5)3(mu-NH)2(mu3-N)}] (3). The analogous reaction of 1 with alkyl, (trimethylsilyl)cyclopentadienyl, or amido zinc complexes [ZnR2] leads to the cube-type derivatives [RZn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (R = CH2SiMe3 (5), CH2Ph (6), Me (7), C5H4SiMe3 (8), N(SiMe3)2 (9)) via RH elimination. The amido complex 9 decomposes in the presence of ambient light to generate the alkyl derivative [{Me3Si(H)N(Me)2SiCH2}Zn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (10). The chloride complex 2 reacts with lithium cyclopentadienyl or lithium indenyl reagents to give the cyclopentadienyl or indenyl zinc derivatives [RZn{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (R = C5H5 (11), C9H7 (12)). Treatment of 1 with copper(I) halides in toluene at room temperature leads to the adducts [XCu{(mu3-NH)3Ti3(eta5-C5Me5)3(mu3-N)}] (X = Cl (13), I (14)). Complex 13 reacts with lithium bis(trimethylsilyl)amido in toluene to give the precipitation of [{Cu(mu4-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}2] (15). Complex 15 is prepared in a higher yield through the reaction of 1 with [{CuN(SiMe3)2}4] in toluene at 150 degrees C. The addition of triphenylphosphane to 15 in toluene produces the single-cube compound [(Ph3P)Cu{(mu3-N)(mu3-NH)2Ti3(eta5-C5Me5)3(mu3-N)}] (16). The X-ray crystal structures of 3, 8, 9, and 15 have been determined.

  1. Copper(II) complex of new non-innocent O-aminophenol-based ligand as biomimetic model for galactose oxidase enzyme in aerobic oxidation of alcohols

    Science.gov (United States)

    Safaei, Elham; Bahrami, Hadiseh; Pevec, Andrej; Kozlevčar, Bojan; Jagličić, Zvonko

    2017-04-01

    Mononuclear copper(II) complex of tetra-dentate o-aminophenol-based ligand (H2LBAPP) has been synthesized and characterized. The three dentate precursor (HLBAP) of the final ligand was synthesized first, while the title four-dentate copper bound ligand was synthesized in situ, isolated only in the final copper species [CuLBAPP]. This copper coordination complex reveals a distorted square-planar geometry around the copper(II) centre by one oxygen and three nitrogen atoms from the coordinating ligand. The ligand is thus twice deprotonated via hydroxy and amine groups. The complex is red, non-typical for copper(II), but the effective magnetic moment of 1.86 B M. and a single isotropic symmetry EPR signal with g 2.059 confirm a S = 1/2 diluted spin system, without copper-copper magnetic coupling. Electrochemical oxidation of this complex yields the corresponding Cu(II)-phenyl radical species. Finally, the title complex CuLBAPP has shown good and selective catalytic activity towards alcohol to aldehyde oxidation, at aerobic room temperature conditions, for a set of different alcohols.

  2. Synthesis and crystal structure of thiosemicarbazide complexes of nickel(II) and copper(II)

    Science.gov (United States)

    Sadikov, G. G.; Antsyshkina, A. S.; Koksharova, T. V.; Sergienko, V. S.; Kurando, S. V.; Gritsenko, I. S.

    2012-07-01

    Thiosemicarbazide complexes of nickel(II) [Ni( TSC)2](H Sal)2 ( I) and copper(II) [Cu( TSC)2](H Sal)2 ( Ia) ( TSC is thiosemicarbazide and H Sal is a salycilate anion), as well as complexes [Ni( TSC)2](SO4) · 2H2O ( II) and [Ni( TSC)3]Cl2 · H2O ( III), are synthesized and characterized by IR spectroscopy and X-ray diffraction. Monoclinic crystals I and Ia are isostructural; space group P21/ n, Z = 2. Crystals II are monoclinic, space group P21/ m, Z = 2. Crystals III are orthorhombic, space group Pbca, Z = 8. In I and Ia, two planar salycilate anions sandwich a planar centrosymmetric [Ni( TSC)2]2+ cation to form a supermolecule. The cation and anions are additionally bound by hydrogen bonds. Other hydrogen bonds connect supermolecules into planar layers. In structure II, centrosymmetric [Ni( TSC)2]2+ cations are connected by π-stacking interactions into supramolecular ensembles of a specific type. The ensembles, water molecules, and (SO4)2- anions are bound in the crystal via hydrogen bonds. In the [Ni( TSC)3]2+ cation of structure III, ligands coordinate the Ni atom by the bidentate chelate pattern with the formation of five-membered metallocycles. These metallocycles have an envelope conformation unlike those in I and II, which are planar. In III (unlike in analogous complexes), a meridional isomer of the coordination octahedron of the Ni atom is formed. Together with Cl1- and Cl2- anions, cations form supermolecules, which are packed into planar layers with a square-cellular structure. The layers are linked by hydrogen bonds formed by crystallization water molecules that are located between the layers.

  3. Sulfate-bridged dimeric trinuclear copper(II–pyrazolate complex with three different terminal ligands

    Directory of Open Access Journals (Sweden)

    Gellert Mezei

    2016-08-01

    Full Text Available The reaction of CuSO4·5H2O, 4-chloropyrazole (4-Cl-pzH and triethylamine (Et3N in dimethylformamide (DMF produced crystals of diaquahexakis(μ-4-chloropyrazolato-κ2N:N′bis(N,N-dimethylformamidedi-μ3-hydroxido-bis(μ4-sulfato-κ4O:O′:O′′:O′′hexacopper(II N,N-dimethylformamide tetrasolvate dihydrate, [Cu3(OH(SO4(C3H2ClN23(C3H7NO(H2O]2·4C3H7NO·2H2O. The centrosymmetric dimeric molecule consists of two trinuclear copper–pyrazolate units bridged by two sulfate ions. The title compound provides the first example of a trinuclear copper–pyrazolate complex with three different terminal ligands on the Cu atoms, and also the first example of such complex with a strongly binding basal sulfate ion. Within each trinuclear unit, the CuII atoms are bridged by μ-pyrazolate groups and a central μ3-OH group, and are coordinated by terminal sulfate, H2O and DMF ligands, respectively. Moreover, the sulfate O atoms coordinate at the apical position to the Cu atoms of the symmetry-related unit, providing square–pyramidal coordination geometry around each copper cation. The metal complex and solvent molecules are involved in O—H...O hydrogen bonds, leading to a two-dimensional network parallel to (10-1.

  4. Inorganic-metalorganic hybrids based on copper(II)-monosubstituted Keggin polyanions and dinuclear copper(II)-oxalate complexes. Synthesis, X-ray structural characterization, and magnetic properties.

    Science.gov (United States)

    Reinoso, Santiago; Vitoria, Pablo; Gutiérrez-Zorrilla, Juan M; Lezama, Luis; San Felices, Leire; Beitia, Javier I

    2005-12-26

    Reaction of in situ generated copper(II)-monosubstituted Keggin polyoxometalates and copper(II)-bipyridine-oxalate complexes in the corresponding alkaline acetate buffer led to the formation of hybrid metal organic-inorganic compounds K(2)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(H(2)O)(2)(mu-ox)}(2)].14H(2)O (1), K(14)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}](2)[SiW(11)O(39)Cu(H(2)O)].55H(2)O (2), (NH(4))(4)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}].10H(2)O (3), and Rb(4)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}].10H(2)O (4). Their structures have been established by single-crystal X-ray diffraction. The main structural feature of these compounds is the presence of copper(II)-monosubstituted alpha-Keggin polyoxoanions as inorganic building blocks, on which the mu-oxalatodicopper metalorganic blocks are supported. Compound 1contains the discrete hybrid polyanion [{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(H(2)O)(2)(mu-ox)}(2)](2)(-), whereas the polymeric hybrid polyanion [{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}(2)](n)(4)(n)(-) gives a monodimensional character to compounds 2-4. Magnetic and EPR results are discussed with respect to the crystal structure of the compounds. DFT calculations on both the [Cu(2)(bpy)(2)(H(2)O)(4)(mu-ox)](2+) cationic complex and the metalorganic blocks have been performed in order to determine the optimized geometry and the magnetic coupling constants, respectively.

  5. New dinuclear copper(II) and zinc(II) complexes for the investigation of sugar-metal ion interactions.

    Science.gov (United States)

    Bera, Manindranath; Patra, Ayan

    2011-10-18

    We have studied the binding interactions of biologically important carbohydrates (D-glucose, D-xylose and D-mannose) with the newly synthesized five-coordinate dinuclear copper(II) complex, [Cu(2)(hpnbpda)(μ-OAc)] (1) and zinc(II) complex, [Zn(2)(hpnbpda)(μ-OAc)] (2) [H(3)hpnbpda=N,N'-bis(2-pyridylmethyl)-2-hydroxy-1,3-propanediamine-N,N'-diacetic acid] in aqueous alkaline solution. The complexes 1 and 2 are fully characterized both in solid and solution using different analytical techniques. A geometrical optimization was made of the ligand H(3)hpnbpda and the complexes 1 and 2 by molecular mechanics (MM+) method in order to establish the stable conformations. All carbohydrates bind to the metal complexes in a 1:1 molar ratio. The binding events have been investigated by a combined approach of FTIR, UV-vis and (13)C NMR spectroscopic techniques. UV-vis spectra indicate a significant blue shift of the absorption maximum of complex 1 during carbohydrate coordination highlighting the sugar binding ability of complex 1. The apparent binding constants of the substrate-bound copper(II) complexes have been determined from the UV-vis titration experiments. The binding ability and mode of binding of these sugar substrates with complex 2 are indicated by their characteristic coordination induced shift (CIS) values in (13)C NMR spectra for carbon atoms C1, C2, and C3 of sugar substrates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Ability of sodium copper chlorophyllin complex to repair photoaged skin by stimulation of biomarkers in human extracellular matrix

    Directory of Open Access Journals (Sweden)

    McCook JP

    2016-07-01

    Full Text Available John P McCook,1 Thomas J Stephens,2 Lily I Jiang,2 Robert M Law,3 Vincent Gotz4 1Discovery Partners LLC, Frisco, 2Thomas J. Stephens & Associates, Inc., Richardson, 3ProPath, Dallas, TX, 4MDRejuvena, Inc., San Diego, CA, USA Purpose: To examine the effect of sodium copper chlorophyllin complex on the expression of biomarkers of photoaged dermal extracellular matrix indicative of skin repair.Patients and methods: Following a previously published 12-day clinical assessment model, skin biopsy samples from the forearms of four healthy females with signs of photoaged skin were obtained and samples were analyzed by immunohistochemistry for key biomarkers of aging skin after each subject was treated with a test material consisting of a gel containing a liposomal dispersion of sodium copper chlorophyllin complex 0.05%, a positive control of tretinoin cream 0.025%, and an untreated negative control.Results: There was a statistically significantly greater amount of fibrillin/amyloid P and epidermal mucins found for skin treated with the test material containing 0.05% sodium copper chlorophyllin complex and the reference control tretinoin 0.025% cream compared to the negative control (untreated site. Expression of procollagen 1 and dermal mucin also showed a greater presence in the samples treated with the test material and the reference control compared to the negative control, though the differences were not statistically significant. No adverse events were observed or reported by the subjects during the course of the study.Conclusion: The results of this human biopsy study suggest that both retinoids and sodium copper chlorophyllin complex have beneficial effects on biomarkers of photoaged skin. Products containing both sodium copper chlorophyllin complex and retinols may provide a dual approach to reversing age-related decreases in hyaluronic acid (HA in the skin: inhibition of the breakdown of HA via sodium copper chlorophyllin complex by inhibition

  7. Increased generation of intracellular reactive oxygen species initiates selective cytotoxicity against the MCF-7 cell line resultant from redox active combination therapy using copper-thiosemicarbazone complexes.

    Science.gov (United States)

    Akladios, Fady N; Andrew, Scott D; Parkinson, Christopher J

    2016-06-01

    The combination of cytotoxic copper-thiosemicarbazone complexes with phenoxazines results in an up to 50-fold enhancement in the cytotoxic potential of the thiosemicarbazone against the MCF-7 human breast adenocarcinoma cell line over the effect attributable to drug additivity-allowing minimization of the more toxic copper-thiosemicarbazone component of the therapy. The combination of a benzophenoxazine with all classes of copper complex examined in this study proved more effective than combinations of the copper complexes with related isoelectronic azines. The combination approach results in rapid elevation of intracellular reactive oxygen levels followed by apoptotic cell death. Normal fibroblasts representative of non-cancerous cells (MRC-5) did not display a similar elevation of reactive oxygen levels when exposed to similar drug levels. The minimization of the copper-thiosemicarbazone component of the therapy results in an enhanced safety profile against normal fibroblasts.

  8. Significance of data treatment and experimental setup on the determination of copper complexing parameters by anodic stripping voltammetry.

    Science.gov (United States)

    Omanović, Dario; Garnier, Cédric; Louis, Yoann; Lenoble, Véronique; Mounier, Stéphane; Pizeta, Ivanka

    2010-04-07

    Different procedures of voltammetric peak intensities determination, as well as various experimental setups were systematically tested on simulated and real experimental data in order to identify critical points in the determination of copper complexation parameters (ligand concentration and conditional stability constant) by anodic stripping voltammetry (ASV). Varieties of titration data sets (Cu(measured)vs. Cu(total)) were fitted by models encompassing discrete sites distribution of one-class and two-class of binding ligands (by PROSECE software). Examination of different procedures for peak intensities determination applied on voltammograms with known preset values revealed that tangent fit (TF) routine should be avoided, as for both simulated and experimental titration data it produced an additional class of strong ligand (actually not present). Peak intensities determination by fitting of the whole voltammogram was found to be the most appropriate, as it provided most reliable complexation parameters. Tests performed on real seawater samples under different experimental conditions revealed that in addition to importance of proper peak intensities determination, an accumulation time (control of the sensitivity) and an equilibration time needed for complete complexation of added copper during titration (control of complexation kinetics) are the keypoints to obtain reliable results free of artefacts. The consequence of overestimation and underestimation of complexing parameters is supported and illustrated by the example of free copper concentrations (the most bioavailable/toxic specie) calculated for all studied cases. Errors up to 80% of underestimation of free copper concentration and almost two orders of magnitude overestimation of conditional stability constant were registered for the simulated case with two ligands. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Copper(II) complex formation equilibria involving L-carnosine, the role in the catalysis of amino acid ester hydrolisis

    Energy Technology Data Exchange (ETDEWEB)

    Shoukry, E.M.; Shoukry, M.M.; Mahgoub, A.E.; Galal, H.M. [Cairo Univ., Cairo (Egypt). Faculty of Science

    2000-10-01

    The binary and ternary complexes of copper(II) involving carnosine (H{sub 3}L), amino acids and DNA constituents were examined. Copper(II) was found to form CuL and CuLH{sub 1} complexes with carnosine. The ternary complexes of Copper(II) with carnosine and DNA constituents are formed in a stepwise mechanism, whereby carnosine binds to copper(II), then followed by ligation of the DNA constituents. The concentration distribution of the various complex species has been evaluated. The hydrolysis of amino acid ester is catalysed by the Cu-carnosine complex. The rate enhancement compared with the fee ester hydrolysis is investigated in terms of the ester coordination mode. [Italian] Sono stati considerati i complessi binari e ternari del rame(II) con la carnosina (H{sub 3}L), amino acidi e constituenti del DNA. Si e' trovato che il rame(II) forma complessi CuL e CuLH{sub 1} con la carnosina. I complessi ternari di rame(II) con carnosina e constitutenti del DNA si formano con un meccanismo a stadi, prima la carnosina lega il rame e successivamente sono legati i constituenti del DNA. E' stata valutata la distribuzione della concentrazione delle varie specie complesse. Il complesso Cu-carnosina catalizza l'idrolisi degli esteri di aminoacidi. L'incremento di velocita', rispetto all'idrolisi dell'estere libero, e' stato studiato in termini di modo di coordinazione dell'estere.

  10. Preparation and Analysis of Complex Barrier Layer of Heterocyclic and Long-Chain Organosilane on Copper Alloy Surface

    Directory of Open Access Journals (Sweden)

    Qian Zhao

    2016-07-01

    Full Text Available A single electrodeposited film of 6-(3-triethoxysilylpropylamino-1,3,5-triazine-2,4-dithiol monosodium (TES on a copper alloy surface was prepared by the galvanostatic method, then octyl-triethoxysilane (OTES or hexadecyl-trimethoxysilane (HDTMS was used to modify the electrodeposited film by the self-assembled technique to fabricate the complex film. The electrodeposition process was inferred by cyclic voltammetry. The single and complex films were characterized by means of contact angle, cyclic voltammetry, Fourier transform infrared spectroscopy (FT-IR, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS and scanning electron microscope (SEM. The results showed that the contact angle of the complex film covering the copper alloy surface was up to 118.1° compared with 89.4° of the bare copper alloy. The cyclic voltammogram, polarization curves and EIS indicated that the anti-corrosion performance of complex film was better than that of single electrodeposited TES film, and the protection efficiency was up to 90.2%.

  11. Induction of Laccase, Lignin Peroxidase and Manganese Peroxidase Activities in White-Rot Fungi Using Copper Complexes

    Directory of Open Access Journals (Sweden)

    Martina Vrsanska

    2016-11-01

    Full Text Available Ligninolytic enzymes, such as laccase, lignin peroxidase and manganese peroxidase, are biotechnologically-important enzymes. The ability of five white-rot fungal strains Daedaleopsis confragosa, Fomes fomentarius, Trametes gibbosa, Trametes suaveolens and Trametes versicolor to produce these enzymes has been studied. Three different copper(II complexes have been prepared ((Him[Cu(im4(H2O2](btc·3H2O, where im = imidazole, H3btc = 1,3,5-benzenetricarboxylic acid, [Cu3(pmdien3(btc](ClO43·6H2O and [Cu3(mdpta3(btc](ClO43·4H2O, where pmdien = N,N,N′,N′′,N′′-pentamethyl-diethylenetriamine and mdpta = N,N-bis-(3-aminopropylmethyl- amine, and their potential application for laccase and peroxidases induction have been tested. The enzyme-inducing activities of the complexes were compared with that of copper sulfate, and it has been found that all of the complexes are suitable for the induction of laccase and peroxidase activities in white-rot fungi; however, the newly-synthesized complex M1 showed the greatest potential for the induction. With respect to the different copper inducers, this parameter seems to be important for enzyme activity, which depends also on the fungal strains.

  12. Multispectroscopic studies on the interaction of a copper(ii) complex of ibuprofen drug with calf thymus DNA.

    Science.gov (United States)

    Shahabadi, Nahid; Shiri, Farshad

    2017-02-01

    The interaction of copper(II)-ibuprofenato complex with calf thymus DNA (ct-DNA) has been explored following, UV-visible spectrophotometry, fluorescence measurement, dynamic viscosity measurements, and circular dichroism spectroscopy. In spectrophotometric studies of ct-DNA it was found that [Cu(ibp) 2 ] 2 can form a complex with double-helical DNA. The association constant of [Cu(ibp) 2 ] 2 with DNA from UV-Vis study was found to be 6.19 × 10 4 L mol -1 . The values of K f from fluorescence measurement clearly underscore the high affinity of [Cu(ibp) 2 ] 2 to DNA. The experimental results showed that the conformational changes in DNA helix induced by [Cu(ibp) 2 ] 2 are the reason for the fluorescence quenching of the DNA-Hoechst system. In addition, the fluorescence emission spectra of intercalated methylene blue (MB) with increasing concentrations of [Cu(ibp) 2 ] 2 represented a significant increase of MB intensity as to release MB from MB-DNA system. The results of circular dichroism (CD) suggested that copper(II)-ibuprofenato complex can change the conformation of DNA. In addition, the results of viscosity measurements suggest that copper(II)-ibuprofenato complex may bind with non-classical intercalative mode. From spectroscopic and hydrodynamic studies, it has been found that [Cu(ibp) 2 ] 2 interacts with DNA by partial intercalation mode which contains intercalation and groove properties.

  13. Synthesis, characterization and toxicity studies of pyridinecarboxaldehydes and L-tryptophan derived Schiff bases and corresponding copper (II) complexes

    Science.gov (United States)

    Malakyan, Margarita; Babayan, Nelly; Grigoryan, Ruzanna; Sarkisyan, Natalya; Tonoyan, Vahan; Tadevosyan, Davit; Matosyan, Vladimir; Aroutiounian, Rouben; Arakelyan, Arsen

    2016-01-01

    Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biological activities and thus actively used in the drug development process. The aim of the present study was the synthesis and characterization of new Schiff bases and their copper (II) complexes, derived from L-tryptophan and isomeric (2-; 3-; 4-) pyridinecarboxaldehydes, as well as the assessment of their toxicity in vitro. The optimal conditions of the Schiff base synthesis resulting in up to 75-85% yield of target products were identified. The structure-activity relationship analysis indicated that the location of the carboxaldehyde group at 2-, 3- or 4-position with regard to nitrogen of the pyridine ring in aldehyde component of the L-tryptophan derivative Schiff bases and corresponding copper complexes essentially change the biological activity of the compounds. The carboxaldehyde group at 2- and 4-positions leads to the higher cytotoxic activity, than that of at 3-position, and the presence of the copper in the complexes increases the cytotoxicity. Based on toxicity classification data, the compounds with non-toxic profile were identified, which can be used as new entities in the drug development process using Schiff base scaffold. PMID:28344771

  14. Benzaldehyde Thiosemicarbazone Derived from Limonene Complexed with Copper Induced Mitochondrial Dysfunction in Leishmania amazonensis

    Science.gov (United States)

    Britta, Elizandra Aparecida; Barbosa Silva, Ana Paula; Ueda-Nakamura, Tânia; Dias-Filho, Benedito Prado; Silva, Cleuza Conceição; Sernaglia, Rosana Lázara; Nakamura, Celso Vataru

    2012-01-01

    Background Leishmaniasis is a major health problem that affects more than 12 million people. Treatment presents several problems, including high toxicity and many adverse effects, leading to the discontinuation of treatment and emergence of resistant strains. Methodology/Principal Findings We evaluated the in vitro antileishmanial activity of benzaldehyde thiosemicarbazone derived from limonene complexed with copper, termed BenzCo, against Leishmania amazonensis. BenzCo inhibited the growth of the promastigote and axenic amastigote forms, with IC50 concentrations of 3.8 and 9.5 µM, respectively, with 72 h of incubation. Intracellular amastigotes were inhibited by the compound, with an IC50 of 10.7 µM. BenzCo altered the shape, size, and ultrastructure of the parasites. Mitochondrial membrane depolarization was observed in protozoa treated with BenzCo but caused no alterations in the plasma membrane. Additionally, BenzCo induced lipoperoxidation and the production of mitochondrial superoxide anion radicals in promastigotes and axenic amastigotes of Leishmania amazonensis. Conclusion/Significance Our studies indicated that the antileishmania activity of BenzCo might be associated with mitochondrial dysfunction and oxidative damage, leading to parasite death. PMID:22870222

  15. First insights on the molybdenum-copper Bled M'Dena complex (Eglab massif, Algeria)

    Science.gov (United States)

    Lagraa, Karima; Salvi, Stefano; Béziat, Didier; Debat, Pierre; Kolli, Omar

    2017-03-01

    Molybdenum-Copper showings in the Eglab massif (eastern part of the Reguibat rise of Algeria), are found in quartz-monzodiorite and granodiorite of the Bled M'Dena complex, a Paleoproterozoic circular structure of ∼5 km in diameter, comprising volcanic and intrusive suites. The latter consist of quartz-diorite, quartz-monzodiorite and granodiorite with a metaluminous normative composition. They display an "adakitic character" with moderate light rare-earth element (LREE) enrichment, minor Eu anomalies, high Sr/Y ratio and low Yb concentration, suggestive of a hydrous, arc magma of volcanic-arc affinity. The mineralization occurs mostly in quartz + molybdenite + chalcopyrite stockwork veins marked by widespread propylitic alteration along the selvages. Molybdenite and chalcopyrite are commonly associated with calcite, which precipitated at relatively late stages of the hydrothermal alteration. Fluid inclusions related to the mineralization stage, range from aqueous to aqueous-carbonic to solid bearing. The latter inclusions have the highest homogenization temperature (up to ∼400 °C), are salt saturated, and commonly contain molybdenite and/or chalcopyrite crystals. The petrology and geochemistry of the host rocks, the style of the hydrothermal alteration, the ore mineral associations, and the characteristics of the fluid inclusions, are all coherent in indicating that the Bled M'Dena represents a Paleoproterozoic porphyry style Mo mineralization, which is far unreported in the African continent.

  16. Benzaldehyde thiosemicarbazone derived from limonene complexed with copper induced mitochondrial dysfunction in Leishmania amazonensis.

    Directory of Open Access Journals (Sweden)

    Elizandra Aparecida Britta

    Full Text Available BACKGROUND: Leishmaniasis is a major health problem that affects more than 12 million people. Treatment presents several problems, including high toxicity and many adverse effects, leading to the discontinuation of treatment and emergence of resistant strains. METHODOLOGY/PRINCIPAL FINDINGS: We evaluated the in vitro antileishmanial activity of benzaldehyde thiosemicarbazone derived from limonene complexed with copper, termed BenzCo, against Leishmania amazonensis. BenzCo inhibited the growth of the promastigote and axenic amastigote forms, with IC(50 concentrations of 3.8 and 9.5 µM, respectively, with 72 h of incubation. Intracellular amastigotes were inhibited by the compound, with an IC(50 of 10.7 µM. BenzCo altered the shape, size, and ultrastructure of the parasites. Mitochondrial membrane depolarization was observed in protozoa treated with BenzCo but caused no alterations in the plasma membrane. Additionally, BenzCo induced lipoperoxidation and the production of mitochondrial superoxide anion radicals in promastigotes and axenic amastigotes of Leishmania amazonensis. CONCLUSION/SIGNIFICANCE: Our studies indicated that the antileishmania activity of BenzCo might be associated with mitochondrial dysfunction and oxidative damage, leading to parasite death.

  17. Oxygen binding and activation by the complexes of PY2- and TPA-appended diphenylglycoluril receptors with copper and other metals

    NARCIS (Netherlands)

    Sprakel, VSI; Feiters, MC; Klaucke, WM; Klopstra, M; Brinksma, J; Feringa, BL; Karlin, KD; Nolte, RJM; Sprakel, Vera S.I.; Feiters, Martin C.; Meyer-Klaucke, Wolfram; Karlin, Kenneth D.; Nolte, Roeland J.M.; Feringa, Bernard

    2005-01-01

    The copper( I) complexes of diphenylglycoluril basket receptors 1 and 2, appended with bis(2-ethylpyridine) amine (PY2) and tris(2-methylpyridine) amine (TPA), respectively, and their dioxygen adducts were studied with low-temperature UV-vis and X-ray absorption spectroscopy (XAS). The copper(I)

  18. Synthesis, structural study and electrochemical properties of copper(II complexes derived from benzene- and p-toluenesulphonylhydrazones

    Directory of Open Access Journals (Sweden)

    A. REGUIG

    2003-02-01

    Full Text Available The synthesis and characterization of benzene- and p-toluenesulphonylhydrazones derived from salicylaldehyde and 2-hydroxy-1-naphthaldehyde and their Cu(II complexes are reported. The compounds were characterized on the basis of elemental analyses, electronic and IR spectra, magnetic moments, and conductance measurements. The electrochemical behavior of the Cu(II complexes was investigated in DMSO by cyclic voltammetry (CV, rotating disc electrode (RDE and coulometry. The oxidative polymerization of the copper complexes on a glassy carbon electrode was carried out in DMSO.

  19. Spectrophotometric determination of formation constants of copper(II) complexes with 2,2‧-bipyridyl, 1,10-phenanthroline and their halides in methanol

    Science.gov (United States)

    Segoviano-Garfias, José J. N.; Nájera-Lara, Mónica; Pérez-Arredondo, María de la Luz; López-Ramírez, Varinia; Rubio-Jimenez, C. A.; Ramírez-Vázquez, Juan Antonio; Moreno-Esparza, Rafael

    2017-11-01

    The redox mediator used in dye-sensitized solar cells present several disadvantages; several research groups have theorized the possible use of blue copper proteins as electron mediators, despite their high costs. Copper complexes that mimic blue copper proteins could represent an alternative as electronic transfer agent with lower costs. In this work, we conducted a spectrophotometric study of the speciation of copper(II) complexes with 2,2‧-bipyridyl, 1,10-phenanthroline and their ternary complexes with chloride and bromide, at 303 K. For the copper-2,2‧-bipyridyl complexes, the formation constants obtained are: log β110 = 7.57 ± 0.08, log β120 = 13.26 ± 0.11 and log β130 = 17.21 ± 0.14. For the ternary systems of copper-2,2‧-bipyridyl with chloride or bromide, are: log β111 = 12.06 ± 0.06 and log β111 = 11.23 ± 0.01, respectively. Also, the formation constants obtained for the copper-1,10-phenanthroline complexes are log β110 = 4.21 ± 0.01 and log β120 = 7.24 ± 0.02. For the ternary systems of copper(II) with 1,10-phenanthroline and chloride or bromide, are: log β111 = 6.14 ± 0.04 and log β111 = 7.46 ± 0.03, respectively. Finally, the individual calculated electronic spectra of these species were obtained and compared to other copper complexes mimicking to blue copper proteins.

  20. Copper(ii) complexes of a polydentate imidazole-based ligand. pH effect on magnetic coupling and catecholase activity.

    Science.gov (United States)

    Mijangos, Edgar; Reedijk, Jan; Gasque, Laura

    2008-04-14

    A potentially dodecadentate N8O4-donor ligand obtained from 2,2'-biimidazole and l-valine and its tetranuclear Cu(ii) complexes in different degrees of protonation were characterized by chemical and spectroscopic methods. The extensive solution studies performed reveal that the rise in pH media leads successively to the formation of imidazolato (pKa(1) and pKa(2) and hydroxido (pKa(3) and pKa(4)) bridges. A frozen solution EPR study shows a decrease in the signal intensity until an EPR silent spectrum is observed, upon increasing the basicity of the solution. The catalytic performance of the oxidation of 3,5-di-tert-butylcatechol to its corresponding quinone was studied using UV-Vis-NIR absorption spectroscopic methods in CH3CN-H2O and in CH3OH-H2O at pH = 7.5, 8.0 and 8.5. A marked increase in activity, consistent with the formation of the hydroxide bridged species, is observed at pH = 8.5 in both solvent mixtures, but the activity is significantly higher in CH3OH-H2O.

  1. Bio-inspired multinuclear copper complexes covalently immobilized on reduced graphene oxide as efficient electrocatalysts for the oxygen reduction reaction.

    Science.gov (United States)

    Xi, Yue-Ting; Wei, Ping-Jie; Wang, Ru-Chun; Liu, Jin-Gang

    2015-05-01

    Inspired by the multicopper active site of laccase, which efficiently catalyzes the oxygen reduction reaction (ORR), herein we report a novel bio-inspired ORR catalyst composed of a multinuclear copper complex that was immobilized on the surface of reduced graphene oxide (rGO) via the covalently grafted triazole-dipyridine (TADPy) dinucleating ligand. This rGO-TADPyCu catalyst exhibited high ORR activity and superior long-term stability compared to Pt/C in alkaline media.

  2. Resonance Raman investigation of the effects of copper binding to iron-mesoporphyrin.histidine-rich glycoprotein complexes

    OpenAIRE

    Larsen, R W; Nunez, D J; Morgan, W. T.; Muhoberac, B B; Ondrias, M.R.

    1992-01-01

    Histidine-rich glycoprotein (HRG) binds both hemes and metal ions simultaneously with evidence for interaction between the two. This study uses resonance Raman and optical absorption spectroscopies to examine the heme environment of the 1:1 iron-mesoporphyrin.HRG complex in its oxidized, reduced and CO-bound forms in the absence and presence of copper. Significant perturbation of Fe(3+)-mesoporphyrin.HRG is induced by Cu2+ binding to the protein. Specifically, high frequency heme resonance Ra...

  3. Synthesis, spectroscopic and thermal studies of the copper(II) aspartame chloride complex

    Science.gov (United States)

    Çakır, S.; Coşkun, E.; Naumov, P.; Biçer, E.; Bulut, İ.; İçbudak, H.; Çakır, O.

    2002-08-01

    Aspartame adduct of copper(II) chloride Cu(Asp) 2Cl 2·2H 2O (Asp=aspartame) is synthesized and characterized by elemental analysis, FT IR, UV/vis, ESR spectroscopies, TG, DTG, DTA measurements and molecular mechanics calculations. Aqueous solution of the green solid absorbs strongly at 774 and 367 nm. According to the FT IR spectra, the aspartame moiety coordinates to the copper(II) ion via its carboxylate ends, whereas the ammonium terminal groups give rise to hydrogen bonding network with the water, the chloride ions or neighboring carboxylate groups. The results suggest tetragonally distorted octahedral environment of the copper ions.

  4. ANTINFLAMMATORY ACTIVITY OF AN N, N'-DISALICYLIDENEMETHYLENDIAMINE-DERIVED SCHIFF BIS BASE AND ITS COPPER(II) COMPLEX.

    Science.gov (United States)

    Tântaru, Gladiola; Nechifor, M; Apostu, M; Vieriu, Mădălina; Panainte, Alina Diana; Bibire, Nela

    2015-01-01

    The cooper(II) complex combination of N, N'-disalicylidenemethylenediamine and the Schiff bis base were investigated for anti-inflammatory activity. In vivo, the anti-inflammatory activity of the metallic complex in comparison with the activity of the Schiff bis base was tested by the method of Winter and co-workers using the Levy technique. Our study on the anti-inflammatory activity of a new Schiff bis base and its complex cooper(II) combination showed that the Schiff bis bases exhibited significant anti-inflammatory action in acute experimental inflammation when compared to the control group. The copper cation from the complex combination enhanced the anti-inflammatory effect of the Schiff bis base, the effect being stronger at doses of 10 mg/kg cooper(II) complex. The Schiff bis base and its cooper(II) complex had an anti-inflammatory effect comparable to that of indomethacin.

  5. An in-vivo study for targeted delivery of copper-organic complex to breast cancer using chitosan polymer nanoparticles.

    Science.gov (United States)

    Pramanik, Arindam; Laha, Dipranjan; Dash, Sandeep Kumar; Chattopadhyay, Sourav; Roy, Somenath; Das, Dipak Kumar; Pramanik, Panchanan; Karmakar, Parimal

    2016-11-01

    We have developed a strategy for targeted delivery of metal-diketo complex, "bis(2,4-pentanedionato) copper(II)" to breast cancer cells both in-vitro and in-vivo. This metal-organic complex induced ROS and subsequently DNA damage as well as mitochondrial membrane depolarization was observed. The mitochondria rupture further triggered apoptosis. For in-vitro targeting strategies, two different approaches were employed, folic acid or her-2 specific peptide (KCCYSL) was attached to stearic acid-modified polymeric Chitosan nanoparticles loaded with metal-organic complex "bis(2,4-pentanedionato)copper(II)". This was tested on two pairs of isogenic cells (FR+/FR- MCf-7 and her2+ /her2- MCF-7) and it was observed that cells expressing the receptor were susceptible to the drug whereas non-expressing isogenic cells were almost un-affected. During in-vivo studies, mice receiving targeted delivery of bis(2,4-pentanedionato) copper (II) had increased survivability and reduced tumor volume compared to non-targeted drug delivery. During toxicity studies for liver enzymes it was also found that the mice receiving targeted drug did not show any sign of liver damage as well as other histology changes. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. DNA condensation by copper(II) complexes and their anti-proliferative effect on cancerous and normal fibroblast cells.

    Science.gov (United States)

    Rajalakshmi, Subramaniyam; Kiran, Manikantan Syamala; Nair, Balachandran Unni

    2014-06-10

    In our search towards copper(II) based anticancer compounds, copper(II) complexes [Cu(bitpy)2](ClO4)21, [Cu(bitpy)(phen)](NO3)22 and [Cu(bitpy)(NO3)](NO3) 3 were synthesized and characterized. All the three complexes contain the tridentate ligand bitpy, which bears biologically relevant benzimidazolyl head group, as one of the ligands. Because of the presence of the planar benzimidazolyl group in the bitpy ligand, the complexes exhibited intercalative mode of binding with DNA. The DNA binding constant, K(b), for complexes 1, 2 and 3 were determined to be (1.84 ± 0.32) × 10(4), (1.83 ± 0.57) × 10(4) and (1.87 ± 0.21) × 10(4) M(-1) respectively. All the three complexes possessed DNA condensing ability. The DNA condensing ability of the complexes was in the order 2 > 1 > 3. The DNA condensation induced by these three complexes was found to be reversed in the presence of 1 M NaCl. In vitro cytotoxicity of three complexes was tested against osteosarcoma MG63 cell line as well as normal fibroblast NIH3T3 cell line by MTT reduction assay. Complexes 1 and 2 were found to be highly toxic towards MG63 than NIH3T3 cell line and both these complexes brought about cell death in the MG-63 cell line due to apoptosis. Whereas, complex 3 exhibited almost equal toxic effect towards both MG63 and NIH3T3 cell lines. Based on the fact that both complexes 1 and 2 brought about reversible condensation of DNA and induced apoptosis in osteosarcoma MG-63 cell line, it is hypothesized that they might possess potential pharmaceutical applications. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Copper(II) complexes with 4-hydroxyacetophenone-derived acylhydrazones: Synthesis, characterization, DNA binding and cleavage properties

    Science.gov (United States)

    Gup, Ramazan; Gökçe, Cansu; Aktürk, Selçuk

    2015-01-01

    Two new Cu(II) complexes of Schiff base-hydrazone ligands, hydroxy-N‧-[(1Z)-1-(4-hydroxyphenyl)ethylidene]benzohydrazide [H3L1] and ethyl 2-(4-(1-(2-(4-(2-ethoxy-2-oxoethoxy)benzoyl)hydrazono)ethyl)phenoxy)acetate (HL2) have been synthesized and then characterized by microcopy and spectral studies. X-ray powder diffraction illustrates that [Cu(L2)2] complex is crystalline in nature whereas [Cu(H2L1)2]·2H2O has an amorphous structure. Binding of the copper complexes with Calf thymus DNA (CT-DNA) has been investigated by UV-visible spectra, exhibiting non-covalent binding to CT-DNA. DNA cleavage experiments have been also investigated by agarose gel electrophoresis in the presence and absence of an oxidative agent (H2O2). The effect of complex concentration on the DNA cleavage reaction has been also studied. Both copper complexes show nuclease activity, which significantly depends on concentrations of the complexes, in the presence of H2O2 through oxidative mechanism whereas they slightly cleavage DNA in the absence an oxidative agent.

  8. Surfactant-copper(II) Schiff base complexes: synthesis, structural investigation, DNA interaction, docking studies, and cytotoxic activity.

    Science.gov (United States)

    Lakshmipraba, Jagadeesan; Arunachalam, Sankaralingam; Solomon, Rajadurai Vijay; Venuvanalingam, Ponnambalam; Riyasdeen, Anvarbatcha; Dhivya, Rajakumar; Akbarsha, Mohammad Abdulkader

    2015-01-01

    A series of surfactant-copper(II) Schiff base complexes (1-6) of the general formula, [Cu(sal-R2)2] and [Cu(5-OMe-sal-R2)2], {where, sal=salicylaldehyde, 5-OMe-sal=5-methoxy- salicylaldehyde, and R2=dodecylamine (DA), tetradecylamine (TA), or cetylamine (CA)} have been synthesized and characterized by spectroscopic, ESI-MS, and elemental analysis methods. For a special reason, the structure of one of the complexes (2) was resolved by single crystal X-ray diffraction analysis and it indicates the presence of a distorted square-planar geometry in the complex. Analysis of the binding of these complexes with DNA has been carried out adapting UV-visible-, fluorescence-, as well as circular dichroism spectroscopic methods and viscosity experiments. The results indicate that the complexes bind via minor groove mode involving the hydrophobic surfactant chain. Increase in the length of the aliphatic chain of the ligands facilitates the binding. Further, molecular docking calculations have been performed to understand the nature as well as order of binding of these complexes with DNA. This docking analysis also suggested that the complexes interact with DNA through the alkyl chain present in the Schiff base ligands via the minor groove. In addition, the cytotoxic property of the surfactant-copper(II) Schiff base complexes have been studied against a breast cancer cell line. All six complexes reduced the visibility of the cells but complexes 2, 3, 5, and 6 brought about this effect at fairly low concentrations. Analyzed further, but a small percentage of cells succumbed to necrosis. Of these complexes (6) proved to be the most efficient aptotoxic agent.

  9. Anti-cancer activity and mutagenic potential of novel copper(II) quinolinone Schiff base complexes in hepatocarcinoma cells.

    Science.gov (United States)

    Duff, Brian; Thangella, Venkat Reddy; Creaven, Bernadette S; Walsh, Maureen; Egan, Denise A

    2012-08-15

    This study determined the cytotoxic, cyto-selective and mutagenic potential of novel quinolinone Schiff base ligands and their corresponding copper(II) complexes in human-derived hepatic carcinoma cells (Hep-G2) and non-malignant human-derived hepatic cells (Chang). Results indicated that complexation of quinolinone Schiff bases with copper served to significantly enhance cytotoxicity. Here, the complex of (7E)-7-(3-ethoxy-2-hydroxybenzylideamino)-4-methylquinolin-2(1H)-one (TV117-FM) exhibited the lowest IC(50) value (17.9 μM) following 96 h continuous exposure, which was comparable to cisplatin (15.0 μM). However, results revealed that TV117-FM lacked cytoselectivity over non-malignant cells. Additionally, the complex was minimally effluxed from cells via Pglycoprotein (P-gp) and was shown to be non-mutagenic in the Standard Ames test. Furthermore, BrdU incorporation assays showed that it was capable of inhibiting DNA synthesis in a concentrationand time-dependent manner. However, inhibition was not as a consequence of DNA intercalation, as illustrated in electrophoretic mobility shift assays. Interestingly, it was shown that the ligand was capable of inhibiting the action of topoisomerase II, but this was lost following complexation. This indicated that the mechanism of action of the novel copper(II) complex was different from that of the parent ligand and suggests that TV117-FM may have a therapeutic role to play in the treatment of hepatocellular carcinoma. Studies are currently underway to elucidate the exact in vitro mechanism of action of this novel, metal-based anti-cancer agent. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Synthesis, micellization behavior, antimicrobial and intercalative DNA binding of some novel surfactant copper(II) complexes containing modified phenanthroline ligands.

    Science.gov (United States)

    Nagaraj, Karuppiah; Ambika, Subramanian; Rajasri, Shanmugasundaram; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-10-01

    The novel surfactant copper(II) complexes, [Cu(ip)2DA](ClO4)21, [Cu(dpqc)2DA](ClO4)22, [Cu(dppn)2DA](ClO4)23, where ip=imidazo[4,5-f][1,10]phenanthroline, dpqc=dipyrido[3,2-a:2',4'-c](6,7,8,9-tetrahydro)phenazine, dppn=benzo[1]dipyrido[3,2-a':2',3'-c]phenazine and DA-dodecylamine, were synthesized and characterized by physico-chemical and spectroscopic methods. In these complexes 1-3, the geometry of copper metal ions was described as square pyramidal. The critical micelle concentration (CMC) value of these surfactant copper(II) complexes in aqueous solution was found out from conductance measurements. Specific conductivity data at different temperatures served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔGm°, ΔHm° and ΔSm°). The binding interaction of these complexes with DNA (calf thymus DNA) in Tris buffer was studied by physico-chemical techniques. In the presence of the DNA UV-vis spectrum of complexes showed red shift of the absorption band along with significant hypochromicity indicating intercalation of our complexes with nucleic acids. Competitive binding study with ethidium bromide (EB) shows that the complexes exhibit the ability to displace the nucleic acid-bound EB indicating that the complexes bind to nucleic acids in strong competition with EB for the intercalative binding site. Observed changes in the circular dichoric spectra of DNA in the presence of surfactant complexes support the strong binding of complexes with DNA. CV results also confirm this mode of binding. Some significant thermodynamic parameters of the binding of the titled complexes to DNA have also been determined. The results reveal that the extent of DNA binding of 3 was greater than that of 1 and 2. The antibacterial and antifungal screening tests of these complexes have shown good results compared to its precursor chloride complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. New structural form of a tetranuclear lanthanide hydroxo cluster: Dy4 analogue display slow magnetic relaxation.

    Science.gov (United States)

    Jami, Ananda Kumar; Baskar, Viswanathan; Sañudo, E Carolina

    2013-03-04

    A series of tetranuclear lanthanide (Ln = Tb, Dy, Ho) hydroxo clusters has been synthesized by reaction of LnCl3·6H2O (Ln = Tb (1), Dy (2), Ho (3)) with o-vanilin based schiff base ligand 2-(2,3 dihydroxpropyl imino methyl) 6-methoxy phenol (H3L) in methanol and in the presence of triethylamine as base. The solid state structures of all the products were established by single crystal X-ray diffraction technique. Magnetism studies reveal that Dy4 analogue exhibits slow magnetic relaxation at low temperatures.

  12. A New Polynuclear Coordination Type for (Salicylaldoxime)copper(II) Complexes: Structure and Magnetic Properties of an (Oxime)Cu6 Cluster

    DEFF Research Database (Denmark)

    Wenzel, Marco; Forgan, Ross S.; Faure, Anaëlle

    2009-01-01

    A previously unseen coordination mode is reported for (salicylaldoxime)copper complexes utilising a linked zwitterionic NO22- donor set. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)......A previously unseen coordination mode is reported for (salicylaldoxime)copper complexes utilising a linked zwitterionic NO22- donor set. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)...

  13. Copper(II) complexes derived from di-2-pyridyl ketone- N4-phenyl-3-semicarbazone: Synthesis and spectral studies

    Science.gov (United States)

    Reena, T. A.; Kurup, M. R. Prathapachandra

    2010-08-01

    Five copper(II) complexes [CuLCl] 2·CuCl 2·4H 2O ( 1), [CuLOAc] ( 2), [CuLNO 3] 2 ( 3), [CuLN 3] ( 4) and [CuLNCS]·3/2H 2O ( 5) of di-2-pyridyl ketone- N4-phenyl-3-semicarbazone (HL) were synthesized and characterized by elemental analyses and electronic, infrared and EPR spectral techniques. In all these complexes the semicarbazone undergoes deprotonation and coordinates through enolate oxygen, azomethine and pyridyl nitrogen atoms. All the complexes are EPR active due to the presence of an unpaired electron. EPR spectra of all the complexes in DMF at 77 K suggest axial symmetry and the presence of half field signals for the complexes 1 and 3 indicates dimeric structures.

  14. Copper(II) and palladium(II) complexes with tridentate NSO donor Schiff base ligand: Synthesis, characterization and structures

    Science.gov (United States)

    Kumar, Sujit Baran; Solanki, Ankita; Kundu, Suman

    2017-09-01

    Mononuclear copper(II) complex [CuL2] and palladium(II) complexes [Pd(X)L] where X = benzoate(bz) or salicylate(sal) and HL = 2-(methylthio)phenylimino)methyl)phenol, a Schiff base ligand with NSO coordination sites have been synthesized and characterized by microanalyses, IR, UV-Visible spectra, conductivity measurement and magnetic studies. Crystal structures of all the complexes have been solved by single crystal X-ray diffraction studies and showed that there are two molecules in a unit cell in the [CuL2] complex - one molecule has square planar geometry whereas second molecule has distorted square pyramidal geometry and palladium(II) complexes have distorted square planar geometry.

  15. Mixed-ligand copper(II) phenolate complexes: Synthesis, spectral characterization, phosphate-hydrolysis, antioxidant, DNA interaction and cytotoxic studies

    Science.gov (United States)

    Gurumoorthy, Perumal; Mahendiran, Dharmasivam; Prabhu, Durai; Arulvasu, Chinnasamy; Rahiman, Aziz Kalilur

    2015-01-01

    A series of phenol-based mixed-ligand copper(II) complexes of the type [CuL1-4(diimine)] (1-8), where L1-4 = N1,N2-bis(5-substituted-2-hydroxybenzylidene)-1,2-ethylene/phenylenediimine and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen), have been isolated and fully characterized by analytical and spectral techniques. Electronic spectra of complexes suggest Cu(II) cation has a d9 electronic configuration, adopting distorted octahedral geometry with axial elongation, due to Jahn-Teller effect. Electrochemical studies of complexes evidenced one-electron irreversible reduction wave in the cathodic region. The observed rate constant (k) values for the hydrolysis of 4-nitrophenylphosphate (4-NPP) are in the range of 0.25-3.82 × 10-2 min-1. The obtained room temperature magnetic moment values (1.79-1.90 BM) lies within the range observed for octahedral copper(II) complexes. Antioxidant studies revealed that these complexes possess considerable radical scavenging potency against DPPH. The binding studies of complexes with calf thymus DNA (CT-DNA) revealed intercalation with minor-groove binding, and the complex 4 exhibits highest binding activity than the other complexes. The cleavage activity on supercoiled pBR322 DNA revealed the involvement of hydroxyl radical and singlet-oxygen as reactive oxygen species, and complexes encourage binding to minor-groove. Further, the cytotoxicity of complex 4 on human hepatocellular liver carcinoma HepG2 cell line implies the cell death through apoptosis.

  16. The Synthesis of a Coumarin Carbohydrazide Dinuclear Copper Complex Based Fluorescence Probe and Its Detection of Thiols.

    Directory of Open Access Journals (Sweden)

    Guangjie He

    Full Text Available Small-molecule thiols, such as cysteine (CYS and glutathione (GSH, are essential for maintaining the cellular redox environment and play important roles in regulating various cellular physiological functions. A fluorescence probe (compound 1-Cu2+ for thiols based on coumarin carbohydrazide dinuclear copper complex was developed. Compound 1 was synthesized from the reaction of 7-(diethylamino-2-oxo-2H-chromene-3-carbohydrazide with 4-tert-butyl-2,6- diformylphenol. Accordingly, the copper complex (compound 1-Cu2+ was prepared by mixing compound 1 with 2 equivalents copper ions. Compound 1 had strong fluorescence while compound 1-Cu2+ hardly possessed fluorescence owing to the quenching nature of paramagnetism Cu2+ to the fluorescence molecule excited state. However, the fluorescence intensity of compound 1-Cu2+ was increased dramatically after the addition of thiol-containing amino acids, but not the other non-sulfhydryl amino acids. UV-vis absorption and fluorescence spectra indicated that compound 1-Cu2+ had good selectivity and sensitivity for thiols such as glutathione in CH3CN:H2O (3:2, v/v PBS solution. The fluorescence imaging experiments implied that compound 1-Cu2+ has potential application in thiol-containing amino acids detection in living cells.

  17. Synthesis and reactivity of copper(I) complexes with an ethylene-bridged bis(imidazolin-2-imine) ligand.

    Science.gov (United States)

    Petrovic, Dejan; Hill, Lyndal M R; Jones, Peter G; Tolman, William B; Tamm, Matthias

    2008-02-21

    A series of copper(I) complexes with a sterically hindered, bidentate ligand, BL iPr, derived from an N-heterocyclic carbene precursor have been isolated, characterized and their reactivity studied. The ethylene-bridged bis(imidazolin-2-imine) ligand (BL iPr) provides strongly donating N-donor atoms for the stabilization of a copper(I) metal center, priming it for reactivity. The complexes [(BL iPr)Cu(XyNC)]PF6 (4) and [(BL iPr)CuCl] (5) were characterized by X-ray crystallography and exhibit trigonal coordination at the copper centers. The reactivity of [(BL iPr)Cu]SbF6 toward dioxygen was studied at low temperature, indicating formation of a thermally sensitive intermediate with intense UV/Vis features and an isotope-sensitive vibration at 625 cm(-1) (599 cm(-1) with 18 O2). The intermediate is assigned as containing the bis(mu-oxo)dicopper(III) core, [2](PF6)2, and the related, stable hydroxo form was crystallized as [{(BL iPr)Cu}2(mu-OH)2](PF6)2, [3](PF6)2. The reactivity of 5 as a catalyst for the ATR polymerization of styrene was assessed in terms of reaction kinetics and polymer properties, with low PDI values achieved for polymers with molecular weights up to 30 000 g mol(-1).

  18. DNA cleavage, structural elucidation and anti-microbial studies of three novel mixed ligand Schiff base complexes of copper(II

    Directory of Open Access Journals (Sweden)

    N. RAMAN

    2007-10-01

    Full Text Available Three new copper complexes of mixed ligands derived from Schiff bases (condensation of p-aminoacetanilide and substituted benzaldehydes with 1,10-phenanthroline have been synthesized and characterized by elemental analysis, IR, UV–Vis, magnetic moments, conductivity and electrochemical measurements. The spectral techniques suggest that all the copper complexes exhibit octahedral geometry. The low electrical conductance of the complexes supports their neutral nature. The monomeric nature of the complexes was assessed from their magnetic susceptibility values. The in vitro biological screening effects of the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus, and Salmonella typhi and the fungi Rhizopus stolonifer and Candida albicans by the serial dilution method. A comparative study of the MIC values of the Schiff bases and their copper complexes indicates that the metal complexes exhibited higher antibacterial activity than the free ligands. The DNA cleavage ability of the complexes was monitored by the gel electrophoresis technique. It was found that electron withdrawing group substituted copper complex had higher DNA cleavage activity than the other copper complexes.

  19. Raman, IR, UV-vis and EPR characterization of two copper dioxolene complexes derived from L-dopa and dopamine.

    Science.gov (United States)

    Barreto, Wagner J; Barreto, Sônia R G; Ando, Rômulo A; Santos, Paulo S; DiMauro, Eduardo; Jorge, Thiago

    2008-12-15

    The anionic complexes [Cu(L(1-))3](1-), L(-)=dopasemiquinone or L-dopasemiquinone, were prepared and characterized. The complexes are stable in aqueous solution showing intense absorption bands at ca. 605 nm for Cu(II)-L-dopasemiquinone and at ca. 595 nm for Cu(II)-dopasemiquinone in the UV-vis spectra, that can be assigned to intraligand transitions. Noradrenaline and adrenaline, under the same reaction conditions, did not yield Cu-complexes, despite the bands in the UV region showing that noradrenaline and adrenaline were oxidized during the process. The complexes display a resonance Raman effect, and the most enhanced bands involve ring modes and particularly the nuCC+nuCO stretching mode at ca. 1384 cm(-1). The free radical nature of the ligands and the oxidation state of the Cu(II) were confirmed by the EPR spectra that display absorptions assigned to organic radicals with g=2.0005 and g=2.0923, and for Cu(II) with g=2.008 and g=2.0897 for L-dopasemiquinone and dopasemiquinone, respectively. The possibility that dopamine and L-dopa can form stable and aqueous-soluble copper complexes at neutral pH, whereas noradrenaline and adrenaline cannot, may be important in understanding how Cu(II)-dopamine crosses the cellular membrane as proposed in the literature to explain the role of copper in Wilson disease.

  20. Copper(II), cobalt(II) and nickel(II) complexes of juglone: synthesis, structure, DNA interaction and enhanced cytotoxicity.

    Science.gov (United States)

    Tabrizi, Leila; Fooladivanda, Mahrokh; Chiniforoshan, Hossein

    2016-12-01

    Three novel copper(II), cobalt(II), and nickel(II) complexes of juglone (Jug) containing 1,10-phenanthroline (phen) ligand, [M(Jug) 2 (phen)] (M = Cu(II), 1, Co(II), 2, and Ni(II), 3), have been synthesized and characterized using, elemental analysis and spectroscopic studies. Their interactions with calf thymus DNA were investigated using viscosity measurements, UV-visible and fluorescence spectrophotometric methods. The catalytic activities on DNA cleavage of the complexes 1-3 were studied, which copper complex 1 showed better catalyst activity in the DNA cleavage process than complexes 2 and 3. The in vitro cytotoxic potential of the complexes 1-3 against human cervical carcinoma (HeLa), human liver hepatocellular carcinoma (HepG-2), and human colorectal adenocarcinoma (HT-29) cells indicated their promising antitumor activity with quite low IC 50 values in the range of 0.09-1.89 μM, which are 75 times lower than those of cisplatin.

  1. Towards a selective adsorbent for arsenate and selenite in the presence of phosphate: Assessment of adsorption efficiency, mechanism, and binary separation factors of the chitosan-copper complex.

    Science.gov (United States)

    Yamani, Jamila S; Lounsbury, Amanda W; Zimmerman, Julie B

    2016-01-01

    The potential for a chitosan-copper polymer complex to select for the target contaminants in the presence of their respective competitive ions was evaluated by synthesizing chitosan-copper beads (CCB) for the treatment of (arsenate:phosphate), (selenite:phosphate), and (selenate:sulfate). Based on work by Rhazi et al., copper (II) binds to the amine moiety on the chitosan backbone as a monodentate complex (Type I) and as a bidentate complex crosslinking two polymer chains (Type II), depending on pH and copper loading. In general, the Type I complex exists alone; however, beyond threshold conditions of pH 5.5 during synthesis and a copper loading of 0.25 mol Cu(II)/mol chitosan monomer, the Type I and Type II complexes coexist. Subsequent chelation of this chitosan-copper ligand to oxyanions results in enhanced and selective adsorption of the target contaminants in complex matrices with high background ion concentrations. With differing affinities for arsenate, selenite, and phosphate, the Type I complex favors phosphate chelation while the Type II complex favors arsenate chelation due to electrostatic considerations and selenite chelation due to steric effects. No trend was exhibited for the selenate:sulfate system possibly due to the high Ksp of the corresponding copper salts. Binary separation factors, α12, were calculated for the arsenate-phosphate and selenite-phosphate systems, supporting the mechanistic hypothesis. While, further research is needed to develop a synthesis method for the independent formation of the Type II complexes to select for target contaminants in complex matrices, this work can provide initial steps in the development of a selective adsorbent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A curcumin-based TPA four-branched copper(II) complex probe for in vivo early tumor detection

    Energy Technology Data Exchange (ETDEWEB)

    Pi, Zongxin [Department of Chemical and Chemical Engineering, Hefei Normal University, Hefei 230001 (China); Wang, Jiafeng; Jiang, Bo [Department of Pharmacy, Anhui University of Chinese Medicine, Hefei 230038 (China); Cheng, Gang [Department of Chemical and Chemical Engineering, Hefei Normal University, Hefei 230001 (China); Zhou, Shuangsheng, E-mail: zshuangsheng@126.com [Department of Pharmacy, Anhui University of Chinese Medicine, Hefei 230038 (China); Center of Modern Experimental Technology, Anhui University, Hefei 230038 (China)

    2015-01-01

    A multibranched Cu(II) complex CuL{sub 2} curcumin-based was synthesized and characterized by single-crystal X-ray diffraction analysis. The photophysical properties of the complex have been investigated both experimentally and theoretically. The results show that the target complex exhibits higher quantum yield and larger two-photon absorption (TPA) cross-section in the near infrared (NIR) region compared with its free ligand. The cell imaging studies in vitro and in vivo reveal that the complex shows good photostability and excellent tumor targeting capability to tested cancerous cells, which can be potentially used for early tumor detection. - Graphical abstract: A multibranched Cu(II) complex was prepared from curcumin. The photophysical properties of the obtained complex have been investigated. The results exhibit that the complex has high capability to test cancerous cells and can distinguish between the cancerous and noncancerous cells, which should be potentially used for early tumor detection. - Highlights: • A novel multi-branched copper complex was synthesized. • The obtained compounds exhibited obvious TPA in high polar solvents. • The complex is a low toxicity at low-micromolar concentrations. • The complex exhibits larger TPA cross-section and brighter TPF imaging. • The complex has excellent targeting capability to tested cancerous cells.

  3. Titanium Dioxide-Grafted Copper Complexes: High-Performance Electrocatalysts for the Oxygen Reduction Reaction in Alkaline Media.

    Science.gov (United States)

    Wang, Fei-Fei; Wei, Ping-Jie; Yu, Guo-Qiang; Liu, Jin-Gang

    2016-01-04

    The sluggish kinetics of the oxygen reduction reaction (ORR) at the cathodes of fuel cells significantly hampers fuel cell performance. Therefore, the development of high-performance, non-precious-metal catalysts as alternatives to noble metal Pt-based ORR electrocatalysts is highly desirable for the large-scale commercialization of fuel cells. TiO2 -grafted copper complexes deposited on multiwalled carbon nanotubes (CNTs) form stable and efficient electrocatalysts for the ORR. The optimized catalyst composite CNTs@TiO2 -ZA-[Cu(phen${{^{{\\rm NO}{_{2}}}}}$)(BTC)] shows surprisingly high selectivity for the 4 e(-) reduction of O2 to water (approximately 97 %) in alkaline solution with an onset potential of 0.988 V vs. RHE, and demonstrates superior stability and excellent tolerance for the methanol crossover effect in comparison to a commercial Pt/C catalyst. The copper complexes were grafted onto the surface of TiO2 through coordination of an imidazole-containing ligand, zoledronic acid (ZA), which binds to TiO2 through its bis-phosphoric acid anchoring group. Rational optimization of the copper catalyst's ORR performance was achieved by using an electron-deficient ligand, 5-nitro-1,10-phenanthroline (phen${{^{{\\rm NO}{_{2}}}}}$), and bridging benzene-1,3,5-tricarboxylate (BTC). This facile approach to the assembly of copper catalysts on TiO2 with rationally tuned ORR activity will have significant implications for the development of high-performance, non-precious-metal ORR catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. The oxidative p-dichlorobenzene dechlorinating in the presence of copper (ΙΙ complexes and nitrogen (ΙΙ, ΙV oxides

    Directory of Open Access Journals (Sweden)

    Valentina Yemelyanova

    2012-12-01

    Full Text Available The results of dechlorination in the solution CuCl2–TBP–NaNO2–О2–Н2О kinetics research are presented in the article. All system components influence to the dechlorination process is studied and quantitatively described. The composition of copper intermediate complexes participating in reaction is studied by the instrumentality of UV-spectroscopy. Established part of binuclear copper complexes in the catalytic intermediate complex constants of formation were estimated and compared with the kinetic and spectrophotometric methods. The composition of the intermediate complexes responsible for process is defined, the mechanism scheme is offered, the p-dichlorobenzene dechlorination limiting stage including redox-disintegration of the intermediate complex consisting of dimeric complex of copper (II, I chloride, nitrogen oxide and p-dichlorobenzene is defined.

  5. Effect of substituent of terpyridines on the in vitro antioxidant, antitubercular, biocidal and fluorescence studies of copper(II) complexes with clioquinol

    Science.gov (United States)

    Kharadi, G. J.

    2014-01-01

    An octahedral complexes of copper with clioquinol(CQ) and substituted terpyridine have been synthesized. The Cu(II) complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1H NMR and FAB mass spectra. Antimycobacterial screening of ligand and its copper compound against Mycobacterium tuberculosis shows clear enhancement in the antitubercular activity upon copper complexation. Ferric-reducing anti-oxidant power of all complexes were measured. The fluorescence spectra of complexes show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity.

  6. The Preparation, Characterization, and Magnetism of Copper 15-Metallacrown-5 Lanthanide Complexes.

    Science.gov (United States)

    Stemmler, Ann J.; Kampf, Jeff W.; Kirk, Martin L.; Atasi, Bassel H.; Pecoraro, Vincent L.

    1999-06-14

    The preparation and characterization of a series of encapsulated-lanthanide 15-metallacrown-5 complexes are reported. Planar ligands such as picoline hydroxamic acid (picha) or nonplanar alpha-amino hydroxamic acids (e.g., glycine hydroxamic acid (glyha)) led to one-step syntheses of metallacrowns in yields as high as 85%. The reaction of the appropriate hydroxamic acid with copper acetate and (1)/(5) equiv of gadolinium(III) or europium(III) nitrates in DMF or water yielded crystals of Gd(NO(3))(3)[15-MC(Cu(II)N(picha))-5], 1, Eu(NO(3))(3)[15-MC(Cu(II)N(picha))-5], 2, and Eu(NO(3))(3)[15-MC(Cu(II)N(glyha))-5], 3. Several other 15-metallacrown-5 complexes were synthesized with (1) Cu(II) or Ni(II) in the metallacrown ring metal position, (2) various lanthanides (La(III), Nd(III), Sm(III), Eu(III), Gd(III), Dy(III), Ho(III), Er(III), and Yb(III)) encapsulated in the center of the ring, and (3) chiral alpha-amino hydroxamic acids (e.g., phenylalanine hydroxamic acid (H(2)pheha), leucine hydroxamic acid (H(2)leuha), and tyrosine hydroxamic acid (H(2)tyrha)). It is believed that all of the complexes containing Cu(II) ions have the ring metals either in four-coordinate, square-planar environments, bound to two tetradentate hydroximate ligands, or in five-coordinate, square-pyramidal geometries if solvent is bound. Spectroscopic and magnetic characterization of the Ni(II) complexes suggests that they are either five- or six-coordinate. The encapsulated lanthanides are generally pentagonal bipyramidal, with five oxygen donors from the metallacrown ring and solvent or bidentate nitrate ions in the axial positions. The circular arrangement of ions results in interesting magnetic behavior. With Dy(III) encapsulated in the center of the ring, a magnetic moment as high as 10.9 &mgr;(B) is achieved. Analysis of the variable-temperature susceptibility of La(NO(3))(3)[15-MC(Cu(II)N(picha))-5] indicates that the five Cu(II) ions are antiferromagnetically coupled, forming an S = (1

  7. Hemoglobin and Myoglobin as Reducing Agents in Biological Systems. Redox Reactions of Globins with Copper and Iron Salts and Complexes.

    Science.gov (United States)

    Postnikova, G B; Shekhovtsova, E A

    2016-12-01

    In addition to reversible O2 binding, respiratory proteins of the globin family, hemoglobin (Hb) and myoglobin (Mb), participate in redox reactions with various metal complexes, including biologically significant ones, such as those of copper and iron. HbO2 and MbO2 are present in cells in large amounts and, as redox agents, can contribute to maintaining cell redox state and resisting oxidative stress. Divalent copper complexes with high redox potentials (E0, 200-600 mV) and high stability constants, such as [Cu(phen)2]2+, [Cu(dmphen)2]2+, and CuDTA oxidize ferrous heme proteins by the simple outer-sphere electron transfer mechanism through overlapping π-orbitals of the heme and the copper complex. Weaker oxidants, such as Cu2+, CuEDTA, CuNTA, CuCit, CuATP, and CuHis (E0 ≤ 100-150 mV) react with HbO2 and MbO2 through preliminary binding to the protein with substitution of the metal ligands with protein groups and subsequent intramolecular electron transfer in the complex (the site-specific outer-sphere electron transfer mechanism). Oxidation of HbO2 and MbO2 by potassium ferricyanide and Fe(3) complexes with NTA, EDTA, CDTA, ATP, 2,3-DPG, citrate, and pyrophosphate PPi proceeds mainly through the simple outer-sphere electron transfer mechanism via the exposed heme edge. According to Marcus theory, the rate of this reaction correlates with the difference in redox potentials of the reagents and their self-exchange rates. For charged reagents, the reaction may be preceded by their nonspecific binding to the protein due to electrostatic interactions. The reactions of LbO2 with carboxylate Fe complexes, unlike its reactions with ferricyanide, occur via the site-specific outer-sphere electron transfer mechanism, even though the same reagents oxidize structurally similar MbO2 and cytochrome b5 via the simple outer-sphere electron transfer mechanism. Of particular biological interest is HbO2 and MbO2 transformation into met-forms in the presence of small amounts of

  8. Complexing of copper in drinking water samples to enhance recovery of Aeromonas and other bacteria.

    Science.gov (United States)

    Versteegh, J F; Havelaar, A H; Hoekstra, A C; Visser, A

    1989-11-01

    The presence of copper in drinking water samples at concentrations as low as 10 micrograms/l resulted in a rapid die-off of aeromonads. Coliform bacteria, heterotrophic plate count bacteria and faecal streptococci were also sensitive to copper but to a lesser degree than aeromonads. The effect was particularly noticeable in soft water (less than 3 meq/l Ca + Mg) and at pH-values below 8.0. The toxic effect of copper concentrations up to 500 micrograms/l could be neutralized for a period of up to 24 h by the addition to samples of 50 mg/l of disodium-ethylene-diamino-tetraacetate (Na2EDTA) and keeping the samples on melting ice.

  9. Phosphorylated α-Synuclein-Copper Complex Formation in the Pathogenesis of Parkinson's Disease

    Science.gov (United States)

    Loera-Arias, Maria De Jesus; Saucedo-Cardenas, Odila; Garcia-Garcia, Aracely

    2017-01-01

    Parkinson's disease is the second most important neurodegenerative disorder worldwide. It is characterized by the presence of Lewy bodies, which are mainly composed of α-synuclein and ubiquitin-bound proteins. Both the ubiquitin proteasome system (UPS) and autophagy-lysosomal pathway (ALS) are altered in Parkinson's disease, leading to aggregation of proteins, particularly α-synuclein. Interestingly, it has been observed that copper promotes the protein aggregation process. Additionally, phosphorylation of α-synuclein along with copper also affects the protein aggregation process. The interrelation among α-synuclein phosphorylation and its capability to interact with copper, with the subsequent disruption of the protein degradation systems in the neurodegenerative process of Parkinson's disease, will be analyzed in detail in this review. PMID:29333317

  10. Phosphorylated α-Synuclein-Copper Complex Formation in the Pathogenesis of Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Juan Antonio Castillo-Gonzalez

    2017-01-01

    Full Text Available Parkinson’s disease is the second most important neurodegenerative disorder worldwide. It is characterized by the presence of Lewy bodies, which are mainly composed of α-synuclein and ubiquitin-bound proteins. Both the ubiquitin proteasome system (UPS and autophagy-lysosomal pathway (ALS are altered in Parkinson’s disease, leading to aggregation of proteins, particularly α-synuclein. Interestingly, it has been observed that copper promotes the protein aggregation process. Additionally, phosphorylation of α-synuclein along with copper also affects the protein aggregation process. The interrelation among α-synuclein phosphorylation and its capability to interact with copper, with the subsequent disruption of the protein degradation systems in the neurodegenerative process of Parkinson’s disease, will be analyzed in detail in this review.

  11. Crystal structure, Hirshfeld surfaces and DNA cleavage investigation of two copper(II) complexes containing polypyridine and salicylide ligands.

    Science.gov (United States)

    Luo, Yang-Hui; Sun, Bai-Wang

    2014-05-21

    Two copper complexes 1 [Cu2(phen)2(salicylaldehyde)2(ClO4)2] and 2 [Cu2 (2,2'-dipyridyl)2(salicylaldehyde)2(ClO4)2] have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. These two complexes were display binuclear structure with Cu(II) ions in distorted octahedral environment but antipodal orientation of the binuclear units between them. Molecular Hirshfeld surfaces revealed that the crystal structures of 1 and 2 were supported mainly by H-H, C-H⋯π, π⋯π (C-C), and C-H⋯O intermolecular interactions. DNA cleavage experiments of complexes 1 and 2 revealed that these complexes can intercalation with DNA. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Extended X-ray absorption fine structure data analysis of copper (II) hydroxamic acid mixed ligand complexes

    Science.gov (United States)

    Parsai, N.; Mishra, A.; Shrivastava, B. D.

    2014-09-01

    The X-ray absorption spectra of copper mixed ligand complexes, having hydroxamic acid as one of the ligands, have been recorded at the K-edge of copper at BL-8 Dispersive EXAFS beamline at the 2.5 GeV INDUS-2 Synchrotron, RRCAT, Indore, India. For the analysis of EXAFS data, crystallographic data of the complex or of its analog is required, which is not available. Hence, for the analysis of EXAFS data, theoretical EXAFS data of the studied complexes have been generated using the EXAFS equation employing computer software program Mathcad. Firstly, the experimental data has been processed using the computer program Athena to obtain the normalized absorption versus energy data. From the experimental EXAFS data, the phase shift parameter (an energy independent constant 5) has been computed using Lytle, Sayers and Stern's (LSS) method. The backscattering amplitude has been taken from the available theoretical tabulations and other parameters have been taken from crystallographic data of the copper metal. Fourier transforms of both the experimental and theoretical data have been computed, and the two Fourier transforms are found to agree with each other for all the complexes. The position of the first peak in the Fourier transform gives the value of the first shell bond length, which is shorter than the actual bond length as a result of energy dependence of the phase factor (5(k)) in the sine function of the EXAFS equation. Since, the Fourier transform method and LSS method both are uncorrected for phase and other parameters of the EXAFS equation, the present method gives phase uncorrected bond length of the first coordination shell.

  13. Oxidative demethylation in monooxygenase model systems. Competing pathways for binuclear and helical multinuclear copper(I) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Gelling, O.J.; Feringa, B.L. (Univ. of Groningen (Netherlands))

    1990-10-10

    The ligand 2,6-bis(N-(2-pyridylethyl)formimidoyl)-1-methoxybenzene (2,6-BPB-1-OCH{sub 3}) (4) reacts with Cu-(CH{sub 3}CN){sub 4}BF{sub 4} to form novel binuclear copper(I) complexes (Cu{sub 2}(2,6-BPB-1-OCH{sub 3})(BF{sub 4}){sub 2}(CH{sub 3}CN){sub 4}) (11) and (Cu{sub 2}(2,6-BPB-1-OCH{sub 3})(BF{sub 4}){sub 2}(CH{sub 2}Cl{sub 2}){sub 0.5}) (14), or the helical polynuclear copper(I) complex (Cu(2,6-BPB-1-OCH{sub 3})(BF{sub 4})){sub n} (16). The complexes mimic certain monooxygenases as they rapidly take up O{sub 2} followed by demethylation of the anisole moiety (up to 95% yield). {sup 18}O experiments are provided that show competing aryl-oxygen ({ge}60%) and alkyl-oxygen (20%) bond cleavage pathways. Introduction of a p-methoxy substituent in the arene moiety of complex 11 decreases the oxygenation rate and led to an unprecedented O{sub 2} induced arene-OCH{sub 3}-OCD{sub 3} exchange at 20{degree}C in CD{sub 3}OD. A mechanistic rational is given.

  14. Copper(II) complexes with 2-pyridineformamide-derived thiosemicarbazones: Spectral studies and toxicity against Artemia salina

    Science.gov (United States)

    Ferraz, Karina O.; Wardell, Solange M. S. V.; Wardell, James L.; Louro, Sonia R. W.; Beraldo, Heloisa

    2009-07-01

    The copper(II) complexes [Cu(H2Am4DH)Cl 2] ( 1), [Cu(H2Am4Me)Cl 2] ( 2), [Cu(H2Am4Et)Cl 2] ( 3) and [Cu(2Am4Ph)Cl] ( 4) with 2-pyridineformamide thiosemicarbazone (H2Am4DH) and its N(4)-methyl (H2Am4Me), N(4)-ethyl (H2Am4Et) and N(4)-phenyl (H2Am4Ph) derivatives were studied by means of infrared and EPR spectral techniques. The crystal structure of 4 was determined. The studied compounds proved to be toxic to Artemia salina, suggesting that they could present cytotoxic activity against solid tumors. Among the free thiosemicarbazones H2Am4Ph presented higher toxicity than all other compounds, which showed comparable effects. In the case of complexes 2 and 3 toxicity is probably attributable to the complex as an entity or to a synergistic effect involving the thiosemicarbazone and copper. H2Am4Ph and complexes 2 and 3 revealed to be the most promising compounds as potential antineoplasic agents.

  15. A one-dimensional chain structure based on unusual tetranuclear manganese(II) clusters.

    Science.gov (United States)

    Che, Guang Bo; Wang, Jian; Liu, Chun Bo; Li, Xiu Ying; Liu, Bo

    2008-11-01

    The title coordination polymer, poly[bis(mu(4)-biphenyl-2,2'-dicarboxylato)(dipyrido[3,2-a:2',3'-c]phenazine)manganese(II)], [Mn(2)(C(14)H(8)O(4))(2)(C(18)H(10)N(4))](n), was obtained through the reaction of MnCl(2).4H(2)O, biphenyl-2,2'-dicarboxylic acid (H(2)dpdc) and dipyrido[3,2-a:2',3'-c]phenazine (L) under hydrothermal conditions. The asymmetric unit contains two crystallographically unique Mn(II) ions, one unique L ligand and two unique dpdc ligands. One Mn ion is six-coordinated by four O atoms from three different dpdc ligands and two N atoms from one L ligand, adopting a distorted octahedral coordination geometry. The distortions from ideal octahedral geometry are largely due to the presence of chelating ligands and the resulting acute N-Mn-N and O-Mn-O angles. The second Mn ion is coordinated in a distorted trigonal bipyramidal fashion by five O atoms from four distinct dpdc ligands. Four Mn(II) ions are bridged by the carboxylate groups of the dpdc ligands to form an unusual tetranuclear Mn(II) cluster. Clusters are further connected by the aromatic backbone of the dicarboxylate ligands, forming a one-dimensional chain structure along the b axis. The title compound is the first example of a chain structure based on a tetranuclear Mn(II) cluster.

  16. Synthesis and characterization of mononuclear copper(II) complex of tetradentate N2S2 donor set and the study of DNA and bovine serum albumin binding

    OpenAIRE

    Sandipan Sarkar; Biswajit Das

    2014-01-01

    One mononuclear copper(II) complex, containing neutral tetradentate NSSN-type ligands, of formulation [Cu II(L 1)Cl]ClO 4 (1), was synthesized and isolated in pure form [where L 1˭ 1,3-bis(3-pyridylmethylthio)propane]. Green-colored copper(II) complex was characterized by physicochemical, spectroscopic methods and conductivity measurement. These experimental data matched well with the proposed structure of the complex. Biological activity of the complex (1) toward calf thymus DNA and bovine s...

  17. Bio-affinity of copper(II) complexes with nitrogen and oxygen donor ligands: Synthesis, structural studies and in vitro DNA and HSA interaction of copper(II) complexes.

    Science.gov (United States)

    Jain, Surbhi; Khan, Tanveer A; Patil, Yogesh P; Pagariya, Darshana; Kishore, Nand; Tapryal, Suman; Naik, Anil D; Naik, Sunil G

    2017-09-01

    Reported herein the binding affinity between Human Serum Albumin and the DNA binding and cleavage activity of three copper(II) complexes, [Cu(phen)(o-van)ClO 4 ] (1), [Cu(phen)(gly)]ClO 4 (2) and [Cu(L 1 ) 2 (H 2 O) 2 ] (3) wherein 1 and 2 are synthesized with 1,10-phenanthroline (phen) and co-ligands (o-van: o-vanillin; gly: glycine) and 3 with a ligand 2-hydroxy-3-methoxybenzylidene-4H-1,2,4-triazol-4-amine (H 1 L 1 ). Complex 2 crystallizes in monoclinic (P21/n) space group shows square pyramidal geometry. The complex 3 crystallizes in monoclinic (P21/a) space group. All the three complexes exhibit binding affinity towards the transport protein Human Serum albumin (HSA). Quantitative evaluation of the thermodynamics of interaction and the results obtained from fluorescence spectroscopy suggest that metal coordinated glycynate, o-vanillin and perchlorate groups have a major role to play in the binding process, the latter two being stronger in the binding of complex 1. The coordinated water in complex 3 also plays an important role in the binding, which makes binding of complex 3 with HSA stronger than that of complex 2. Experimental results indicate that the binding affinity of the complexes towards CT-DNA is in the order 1>3>2 implying that complex 1 binds stronger than complex 3 and 2.The DNA cleaving activity of all the three complexes was explored in the presence of reactive oxygen compound, H 2 O 2 . All the three complexes have primarily shown the DNA cleaving activity. Copyright © 2017. Published by Elsevier B.V.

  18. Synthesis and characterization of mononuclear copper(II complex of tetradentate N2S2 donor set and the study of DNA and bovine serum albumin binding

    Directory of Open Access Journals (Sweden)

    Sandipan Sarkar

    2014-12-01

    Full Text Available One mononuclear copper(II complex, containing neutral tetradentate NSSN-type ligands, of formulation [Cu II(L 1Cl]ClO 4 (1, was synthesized and isolated in pure form [where L 1˭ 1,3-bis(3-pyridylmethylthiopropane]. Green-colored copper(II complex was characterized by physicochemical, spectroscopic methods and conductivity measurement. These experimental data matched well with the proposed structure of the complex. Biological activity of the complex (1 toward calf thymus DNA and bovine serum albumin has been examined systematically and groove-binding behavior of the Copper(II complex 1 with calf thymus DNA has been observed from the spectral study.

  19. Biodiesel Production by Catalytic Esterification of Oleic Acid over Copper (II)-Alginate Complexes.

    Science.gov (United States)

    Zhang, Qiuyun; Wei, Fangfang; Zhang, Yutao; Wei, Fuhua; Ma, Peihua; Zheng, Wei; Zhao, Yongting; Chen, Hongliang

    2017-01-01

    A systematic study on copper (II)-alginate beads as catalysts for the synthesis of biodiesel via esterification of oleic acid and methanol is here reported for the first time. The chemical structure and morphologies of these catalysts were fully characterized by XRD, FT-IR, and SEM. The copper (II)-alginate beads showed a tubular structure with entangled reticulation. In the presence of copper (II)-alginate catalyst, the biodiesel conversion of 71.8% was achieved from oleic acid with methanol under the most mild conditions (1/10 oleic acid to methanol molar ratio, 250 mg catalyst, 70°C for 3 h), optimized by single-factor experiments. The catalyst could be easily separated from the reaction mixture and stabilized for a certain time. This material can also catalyze other esterification of fatty acids with different carbon chain lengths, as well as the pretreatment of non-edible oils with high acid value. Our findings showed that the copper (II)-alginate is a suitable catalyst for esterification and would provide more choices for industrial application in the future.

  20. potentiometric studies of the complexes formed by copper (ii) and zinc

    African Journals Online (AJOL)

    MBI

    , P. M. B. 3011, Kano, Nigeria e-mail: jnaaliya@yahoo.com. ABSTRACT. The overall stability constants of copper (II) and zinc (II) ions with some polar uncharged amino acids including proline, threonine and asparagines were determined by ...

  1. The Stoichiometry of Isoquercitrin Complex with Iron or Copper Is Highly Dependent on Experimental Conditions

    Czech Academy of Sciences Publication Activity Database

    Catapano, M.C.; Tvrdý, V.; Karlíčková, J.; Migkos, T.; Valentová, Kateřina; Křen, Vladimír; Mladěnka, P.

    2017-01-01

    Roč. 9, č. 11 (2017), s. 1193 ISSN 2072-6643 R&D Projects: GA MŠk(CZ) LD15082 Institutional support: RVO:61388971 Keywords : chelator * copper * quercetin-3-O-beta-glucopyranoside Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 3.550, year: 2016

  2. Acid-induced mechanism change and overpotential decrease in dioxygen reduction catalysis with a dinuclear copper complex.

    Science.gov (United States)

    Das, Dipanwita; Lee, Yong-Min; Ohkubo, Kei; Nam, Wonwoo; Karlin, Kenneth D; Fukuzumi, Shunichi

    2013-03-13

    Catalytic four-electron reduction of O2 by ferrocene (Fc) and 1,1'-dimethylferrocene (Me2Fc) occurs efficiently with a dinuclear copper(II) complex [Cu(II)2(XYLO)(OH)](2+) (1), where XYLO is a m-xylene-linked bis[(2-(2-pyridyl)ethyl)amine] dinucleating ligand with copper-bridging phenolate moiety], in the presence of perchloric acid (HClO4) in acetone at 298 K. The hydroxide and phenoxo group in [Cu(II)2(XYLO)(OH)](2+) (1) undergo protonation with HClO4 to produce [Cu(II)2(XYLOH)](4+) (2) where the two copper centers become independent and the reduction potential shifts from -0.68 V vs SCE in the absence of HClO4 to 0.47 V; this makes possible the use of relatively weak one-electron reductants such as Fc and Me2Fc, significantly reducing the effective overpotential in the catalytic O2-reduction reaction. The mechanism of the reaction has been clarified on the basis of kinetic studies on the overall catalytic reaction as well as each step in the catalytic cycle and also by low-temperature detection of intermediates. The O2-binding to the fully reduced complex [Cu(I)2(XYLOH)](2+) (3) results in the reversible formation of the hydroperoxo complex ([Cu(II)2(XYLO)(OOH)](2+)) (4), followed by proton-coupled electron-transfer (PCET) reduction to complete the overall O2-to-2H2O catalytic conversion.

  3. A combination of experimental and computational studies on a new oxamido bridged dinuclear copper(II) complex

    Science.gov (United States)

    Bhattacharya, Arnab; Saha, Pinki; Saha, Baptu; Maiti, Debasish; Mitra, Partha; Naskar, Jnan Prakash; Chowdhury, Shubhamoy

    2017-10-01

    Reaction of N,N‧-bis(2-pyridylmethyl)oxamide (H2L), and copper(II)nitrate trihydrate in 1:2 M proportion in methanol generates oxamido bridged dimeric copper(II) compound, [Cu2L(H2O)2(NO3)2]H2O (1a.H2O) in good yield. 1a.H2O has been characterized by C, H and N microanalyses, copper estimation, FT-IR, UV-Vis and room temperature magnetic susceptibility measurements. The X-ray crystal structure of 1a.H2O has been determined. Bond Valence Sum (BVS) analysis was undertaken to assign the oxidation state of each copper center in 1a. Thermal behavior of 1a.H2O has been studied by TGA. Electrochemical studies on 1a.H2O shows single electron two step sequential reductions of Cu(II) to Cu(I) in dimethyl sulphoxide. Our optimized geometry of 1a as obtained through conceptual Density Functional Theory (DFT) corroborates well with that obtained from single crystal X-ray diffraction. TD-DFT method was also adopted to delve into the electronic properties of 1a. We have taken recourse to employ our optimized structure of 1a to investigate systematically the relative stabilities of various dimeric Cu(II) complexes obtained through variation of ligands bearing uni-donor anion through substitution of nitrate in 1a. The in vitro antibacterial potentiality of 1a.H2O was also tested against some bacterial cell lines, pathogenic to mankind.

  4. The coordination structure of the extracted copper(II) complex with a synergistic mixture containing dinonylnaphthalene sulfonic acid and n-hexyl 3-pyridinecarboxylate ester

    Science.gov (United States)

    Zhu, Shan; Hu, Huiping; Hu, Jiugang; Li, Jiyuan; Hu, Fang; Wang, Yongxi

    2017-09-01

    In continuation of our interest in the coordination structure of the nickel(II) complex with dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexyl 4-pyridinecarboxylate ester (4PC), it was observed that the coordination sphere was completed by the coordination of two N atoms of pyridine rings in ligands 4PC and four water molecules while no direct interaction between Ni(II) and deprotonated HDNNS was observed. To investigate whether the coordination structure of nickel(II) with the synergistic mixture containing HDNNS and 4PC predominates or not in the copper(II) complex with the synergistic mixtures containing HDNNS and pyridinecarboxylate esters, a copper(II) synergist complex with n-hexyl 3-pyridinecarboxylate ester (L) and naphthalene-2-sulfonic acid (HNS, the short chain analogue of HDNNS), was prepared and studied by X-ray single crystal diffraction, elemental analyses and thermo gravimetric analysis (TGA), respectively. It was shown that the composition of the copper(II) synergist complex was [Cu(H2O)2(L)2(NS)2] and formed a trans-form distorted octahedral coordination structure. Two oxygen atoms of the two coordinated water molecules and two N atoms of the pyridine rings in the ligands L defined the basal plane while two O atoms from two sulfonate anions of the deprotonated HNS ligands occupied the apical positions by direct coordination with Cu(II), which was distinguished from the coordination structure of the nickel(II) synergist complex as reported in our previous work. In the crystal lattice, neighboring molecules [Cu(H2O)2L2(NS)2] were linked through the intermolecular hydrogen bonds between the hydrogen atoms of the coordinated water molecules and the oxygen atoms of the sulfonate anions in the copper(II) synergist complex to form a 2D plane. In order to bridge the gap between the solid state structure of the copper(II) synergist complex and the solution structure of the extracted copper(II) complex with the actual synergistic mixture containing

  5. An investigation into the unusual linkage isomerization and nitrite reduction activity of a novel tris(2-pyridyl) copper complex

    Science.gov (United States)

    Roger, Isolda; Wilson, Claire; Senn, Hans M.; Sproules, Stephen; Symes, Mark D.

    2017-08-01

    The copper-containing nitrite reductases (CuNIRs) are a class of enzymes that mediate the reduction of nitrite to nitric oxide in biological systems. Metal-ligand complexes that reproduce the salient features of the active site of CuNIRs are therefore of fundamental interest, both for elucidating the possible mode of action of the enzymes and for developing biomimetic catalysts for nitrite reduction. Herein, we describe the synthesis and characterization of a new tris(2-pyridyl) copper complex ([Cu1(NO2)2]) that binds two molecules of nitrite, and displays all three of the common binding modes for NO2-, with one nitrite bound in an asymmetric quasi-bidentate κ2-ONO manner and the other bound in a monodentate fashion with a linkage isomerism between the κ1-ONO and κ1-NO2 binding modes. We use density functional theory to help rationalize the presence of all three of these linkage isomers in one compound, before assessing the redox activity of [Cu1(NO2)2]. These latter studies show that the complex is not a competent nitrite reduction electrocatalyst in non-aqueous solvent, even in the presence of additional proton donors, a finding which may have implications for the design of biomimetic catalysts for nitrite reduction.

  6. Inhibition of the hemolytic activity caused by Staphylococcus aureus alpha-hemolysin through isatin-Schiff copper(II) complexes.

    Science.gov (United States)

    Melo, Maria C A; Teixeira, Luciana R; Pol-Fachin, Laercio; Rodrigues, Claudio G

    2016-01-01

    A great number of pathogens secrete pore-forming proteins during infection. Such molecules, from either bacterial or viral origin, are considered important virulence factors, which makes them attractive targets in the study of new therapeutic agents. Thus, the inhibitory activity of isatin-Schiff base copper(II) complexes was evaluated against membrane damage activity of Staphylococcus aureus α-hemolysin (α-HL). For this purpose, a standard hemolysis assay with rabbit erythrocytes and micromolar concentrations of the compounds was employed. Additionally, planar artificial lipid membranes with a single α-HL ion channel and molecular docking studies were used to elucidate the molecular mechanism of the complexes. Accordingly, the compounds were observed to possess a significant anti-hemolytic activity, capable of interacting with the constriction region of α-HL channel and blocking it in a potential dependent manner. Based on these results, it is expected that such isatin-Schiff base Copper(II) complexes may be employed as cotherapeutic agents for the treatment of staphylococcal infections. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. New tridentate azo-azomethines and their copper(II) complexes: Synthesis, solvent effect on tautomerism, electrochemical and biological studies

    Science.gov (United States)

    Sarigul, Munire; Deveci, Pervin; Kose, Muhammet; Arslan, Ugur; Türk Dagi, Hatice; Kurtoglu, Mukerrem

    2015-09-01

    In this study, three azo-azomethines and their copper(II) complexes were prepared and characterized by analytical and spectroscopic methods. The complexes prepared were found to be mononuclear and the chelation of the ligands to the copper(II) ions occurs through two phenolic oxygens and a nitrogen atom of the azomethine group of the ligand. The tautomeric behaviors of the azo-azomethines in solution were studied by UV-Vis. spectra in three organic solvents with different polarity (CHCl3, DMSO and DMF) at room temperature. The redox behaviors of the azo-azomethines and their Cu(II) complexes were investigated by cyclic voltammetry (CV) in DMSO solution containing 0.1 M tetrabutylammonium tetrafluoroborate (TBATFB) as supporting electrolyte. Additionally, the antibacterial activity was also evaluated by the broth microdilution methods against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The compounds were found to be less effective against all bacteria tested than two reference antibiotics (ampicillin and gentamicin).

  8. Photoluminescent Copper(I) Complex Based on 3-(2-(Cyclohexylthio) ethoxy)pyridine: Synthesis, Structure, and Physical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyunjin; Kwon, Eunjin; Kang, Gihaeng; Kim, Jieun; Kim, Tae Ho [Gyeongsang National University, Jinju (Korea, Republic of)

    2016-07-15

    In recent years, the Cu(I) complexes, with d 10 electronic configuration, have been attracting interest due to their diverse structures and photophysical properties. A copper(I) coordination polymer 1 based on a sulfur-containing pyridyl ligand L was synthesized and identified by X-ray crystallography. Photophysical and thermal properties of 1 have been investigated. More Cu(I) coordination polymers based on mixed donor ligands are under investigation in order to discover factors governing luminescence wavelength, such as Cu[BOND]Cu distances, intermolecular interactions, structures of ligands, and so on.

  9. Synthesis, Crystal Structure, and Characterization of Ternary Copper(II Complex Derived from N-(salicylidene-L-valine

    Directory of Open Access Journals (Sweden)

    Sundaramurthy Santha Lakshmi

    2016-01-01

    Full Text Available Ternary Schiff base copper(II complex [CuL(tmpda] (where H2L is N-(salicylidene-L-valine; tmpda is N,N,N′,N′-tetramethyl-1,3-propanediamine has been characterized by UV-Vis., FTIR, and single crystal XRD. The crystal structure displays a distorted square pyramidal geometry in which Schiff base is bonded to the Cu(II ion via phenolate oxygen, imine nitrogen, and an oxygen atom of the carboxylate group through the basal plane and the chelating diamine, N,N,N′,N′-tetramethyl-1,3-propanediamine, displays an axial and equatorial mode of binding via NN-donor atoms.

  10. Copper (II) complexes of N4, N4-disubstituted thio- and selenosemicarbazones of 2-acetylpyridine: ESR studies

    Science.gov (United States)

    K. Bhoon, Yudhvir; Scovill, John P.; Klayman, Daniel L.

    Copper(II) complexes of 3-azabicyclo[3.2.2]nonane-3-thiocarboxylic acid 2-[1-(pyridinyl)ethylidene]hydrazide, and its selenium analog, 3-azabicyclo[3.2.2]nonane-3-selenocarboxylic acid 2-[1-(2-pyridinyl)ethylidene]hydrazide, were studied by ESR spectrometry in chloroform solution at room temperature and at liquid nitrogen temperature. ESR spectra were also observed for the complexes as magnetically doped samples in the corresponding Ni(II) lattices at room temperature. Nitrogen superhyperfine splitting is observed at room temperature in all the spectra. Splitting patterns indicate the non-equivalent nature of the two coordinating nitrogen atoms. The covalency parameter for the metal—ligand bond was determined for selected complexes. An order of ligand field strength has been proposed based on the magnitude of the g| component of g observed in the polycrystalline state.

  11. Selective DNA Strand Scission with Binuclear Copper Complexes: Implications for an Active Cu2-O2 Species

    Science.gov (United States)

    Thyagarajan, Sunita; Murthy, N. N.; Narducci Sarjeant, Amy A.; Karlin, Kenneth D.; Rokita, Steve E.

    2008-01-01

    A homologous series of binuclear copper(II) complexes [CuII2(Nn)(Y)2]2+ (1–3) (n = 3–5 and Y = (ClO4)− or (NO3)−) were studied to investigate the intermediate(s) responsible for selective DNA strand scission in the presence of MPA/O2 (MPA = 3-mercaptopropanoic acid). While the N3 complex does not react, the N4 and N5 analogues show comparable activity with strand scission occurring at a single-strand/double-strand junction. Identical reactivity is also observed in the alternate presence of H2O2. Spectroscopic and reactivity studies with [CuII2(N4)(Y)2]2+ (2) and H2O2 are consistent with DNA oxidation mediated by formation of a side-on peroxodicopper(II) (Cu2–O2) complex. PMID:16719480

  12. Biphenyl derived oxovanadium(IV) and copper(II) salen-type complexes--structure and redox tuning.

    Science.gov (United States)

    Plitt, Patrick; Pritzkow, Hans; Oeser, Thomas; Kraemer, Roland

    2005-05-01

    A series of vanadyl(IV) salen (N,N'-bis(salicylidene)ethylenediaminato)-type complexes (1-4) bearing phenyl or 2-hydroxyphenyl moieties have been prepared and characterized by means of mass spectrometry, infra-red, electron paramagnetic resonance (EPR), UV/Vis spectroscopy, cyclovoltammetry and X-ray crystallography. Their structures have been compared to their copper(II) analogs 5-8. Hydrogen intralinkages have been observed in the crystal structure of 5. The pendant hydroxy groups fine-tune the redox properties of the complexes. The catalytic activity in the oxygenation of ethyl phenyl sulfide to the corresponding sulfoxide was investigated. Results indicate that complex 1 bearing hydroxyphenyl subunits and a phenylene bridge is the most selective under these reaction conditions, with the smallest amount of the over-oxidized product, sulfone.

  13. New discrete and polymeric supramolecular architectures derived from dinuclear (bis-beta-diketonato)copper(II) metallocycles.

    Science.gov (United States)

    Clegg, Jack K; Gloe, Karsten; Hayter, Michael J; Kataeva, Olga; Lindoy, Leonard F; Moubaraki, Boujemaa; McMurtrie, John C; Murray, Keith S; Schilter, David

    2006-09-07

    New examples of adducts between di- (and, in one instance, tetra-) functional nitrogen ligands and planar 'platform-like' dinuclear copper(II) complexes, [Cu2L2], incorporating the 1,3-aryl linked bis-beta-diketonato bridging ligand 1,1'-(1,3-phenylene)-bis(4,4-dimethylpentane-1,3-dione) (H2L) have been synthesised. The X-ray structures of six adduct species are reported. The interaction of [Cu2(L)2] with the ditopic ligand aminopyrazine (apyz) yielded the sandwich-like tetranuclear species [(Cu2L2(apyz))2]. A variable-temperature magnetochemical investigation of this product indicated weak antiferromagnetic coupling between the (five-coordinate) copper centres, mediated by the 2-aminopyrazine linkers. An analogous structure, [(Cu2L2(dabco))2] (dabco=1,4-diazabicyclo[2.2.2]octane), was generated when dabco was substituted for aminopyrazine while use of 4,4'-dipyridyl sulfide (dps) and 4,4'-(1,3-xylylene)-bis(3,5-dimethylpyrazole) (xbp) as the ditopic 'spacer' ligands resulted in polymeric species of type [Cu2L2(dps)]n and [Cu2L2(xbp)]n, respectively. These latter species exist as one-dimensional chain structures in which copper(II) centres on different dinuclear platforms are linked in a 'zigzag' fashion. In contrast, with 2,2'-dipyridylamine (dpa) a discrete complex of type [Cu2L2(dpa)2] formed in which one potential pyridyl donor from each 2,2'-dipyridylamine ligand remains uncoordinated. The use of the potentially quadruply-bridging hexamethylenetetramine (hmt) ligand as the linker unit was found to give rise to an unusual two-dimensional polymeric motif of type [(Cu2(L2)2)3(hmt)2]n. The product takes the form of a (6,3) network, incorporating triply bridging hexamethylenetetramine units.

  14. Copper(II) complex of methionine conjugated bis-pyrazole based ligand promotes dual pathway for DNA cleavage.

    Science.gov (United States)

    Bhattacharyya, Sudipta; Sarkar, Amrita; Dey, Suman Kr; Jose, Gregor P; Mukherjee, Arindam; Sengupta, Tapas K

    2013-08-28

    Three Cu(II) complexes of bis-pyrazole based ligands have been synthesized and structurally characterized by X-ray crystallography. One of the ligand (L2) contains a methionine ester conjugated to a bis-pyrazole carboxylate through an amide linkage. The binding constant for complexes 1-3 with CT DNA are of the order of 10(4) M(-1). The crystal structure suggests that the axial Cu-O bonds (ca. 2.31(4) Å) are relatively labile and hence during the redox cycle with ascorbic acid and oxygen one or both the axial Cu-O bonds might open to promote copper oxygen reaction and generate ROS. The chemical nuclease activity of complexes 1-3 in dark, show complete relaxation of supercoiled DNA at 100 μM concentration in presence of ascorbic acid (H2A). The mechanistic investigation suggests that the complexes 1 and 2 show involvement of peroxo species whereas 3 shows involvement of both singlet oxygen and peroxo species in DNA cleavage. The singlet oxygen formation in dark is otherwise unfavourable but the presence of methionine as pendant arm in L2 might activate the generation of singlet oxygen from the metal generated peroxo species. The results of DNA cleavage studies suggest that methionine based copper(II) complexes can promote dual pathway for DNA cleavage. Probing the cytotoxic activity of these complexes on MCF-7, human breast cancer cell line shows that 3 is the most effective one with an IC50 of 70(2) μM.

  15. Effect of the Schiff base complex diaqua-(N-salicylidene-l-glutamato)copper(II) monohydrate on human tumor cells.

    Science.gov (United States)

    Konarikova, Katarina; Andrezalova, Lucia; Rapta, Peter; Slovakova, Marianna; Durackova, Zdenka; Laubertova, Lucia; Gbelcova, Helena; Danisovic, Lubomir; Bohmer, Daniel; Ruml, Tomas; Sveda, Martin; Zitnanova, Ingrid

    2013-12-05

    The aim of our study was to estimate cytostatic/cytotoxic activity of the copper(II) Schiff base complex of the composition [Cu(N-salicylidene-l-glutamato)(H2O)2]·H2O, further Cu(SG-L)H2O, against human colon carcinoma cell line HT-29, as well as to determine type of cell death and to find out the molecular mechanism of apoptosis induced by this complex. Two highest concentrations (50, 100 µmol/l) of the complex showed a strong cytotoxic activity against human colon carcinoma cells HT-29 after 72 h of influence. Other concentrations had a cytostatic activity. Unchelated copper(II) ions and free ligands had no effect on the cell growth. Cu(SG-L)H2O preferentially reduced cancer cell viability compared to healthy cells (NIH-3T3). Cu(SG-L)H2O induced apoptosis of cells HT-29 at all concentrations used (1-100 µmol/l) after 48 h of influence. Apoptosis was carried out by the mitochondrial pathway with active caspases 3 and 9. By the spin-trapping technique combined with electron paramagnetic resonance we found that our complex is photochemically stable in aqueous systems and does not exhibit radical-scavenging activity when 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) cation radical was used as an oxidant. The complex exhibits a strong prooxidant property in the initial stages of thermal decomposition of K2S2O8 in water solutions leading to the massive production of (·)OH radicals. Therefore, this complex could strongly participate in anticancer action via a free radical mechanism. © 2013 Elsevier B.V. All rights reserved.

  16. Copper-Sulfur Complexes Supported by N-Donor Ligands: Towards Models of the CuZ Site in Nitrous Oxide Reductase

    OpenAIRE

    York, John T.; Bar-Nahum, Itsik; Tolman, William B.

    2008-01-01

    The distinctive structure of the [(his)7Cu4(μ-S)]n+ cluster in the “CuZ” active site of nitrous oxide reductase and the intriguing mechanistic hypotheses for its catalytic reactivity provide inspiration for synthetic model studies aimed at characterizing relevant copper-sulfur compounds and obtaining fundamental insights into structure and bonding. In this brief review, we summarize such studies that have focused on the synthesis and characterization of a range of copper-sulfur complexes supp...

  17. Electrocatalytic Water Oxidation by a Water-Soluble Copper(II) Complex with a Copper-Bound Carbonate Group Acting as a Potential Proton Shuttle.

    Science.gov (United States)

    Chen, Fangfang; Wang, Ni; Lei, Haitao; Guo, Dingyi; Liu, Hongfei; Zhang, Zongyao; Zhang, Wei; Lai, Wenzhen; Cao, Rui

    2017-11-06

    Water-soluble copper(II) complexes of the dianionic tridentate pincer ligand N,N'-2,6-dimethylphenyl-2,6-pyridinedicarboxamidate (L) are catalysts for water oxidation. In [L-Cu II -DMF] (1, DMF = dimethylformamide) and [L-Cu II -OAc] - (2, OAc = acetate), ligand L binds Cu II through three N atoms, which define an equatorial plane. The fourth coordination site of the equatorial plane is occupied by DMF in 1 and by OAc - in 2. These two complexes can electrocatalyze water oxidation to evolve O 2 in 0.1 M pH 10 carbonate buffer. Spectroscopic, titration, and crystallographic studies show that both 1 and 2 undergo ligand exchange when they are dissolved in carbonate buffer to give [L-Cu II -CO 3 H] - (3). Complex 3 has a similar structure as those of 1 and 2 except for having a carbonate group at the fourth equatorial position. A catalytic cycle for water oxidation by 3 is proposed based on experimental and theoretical results. The two-electron oxidized form of 3 is the catalytically active species for water oxidation. Importantly, for these two oxidation events, the calculated potential values of E p,a = 1.01 and 1.59 V vs normal hydrogen electrode (NHE) agree well with the experimental values of E p,a = 0.93 and 1.51 V vs NHE in pH 10 carbonate buffer. The potential difference between the two oxidation events is 0.58 V for both experimental and calculated results. With computational evidence, this Cu-bound carbonate group may act as a proton shuttle to remove protons for water activation, a key role resembling intramolecular bases as reported previously.

  18. Experimental and molecular modeling studies on the DNA-binding of diazacyclam-based acrocyclic copper complex.

    Science.gov (United States)

    Shahabadi, Nahid; Hakimi, Mohammad; Morovati, Teimoor; Falsafi, Monireh; Fili, Soraya Moradi

    2017-02-01

    The interaction of a new macrocyclic copper complex, [CuL(NO 3 ) 2 ] in which L is 1,3,6,10,12,15-hexaaza tricyclo[13.3.1.1 6,10 ] eicosane was investigated in vitro under simulated physiological conditions by multi-spectroscopic techniques and molecular modeling study. The fluorescence spectroscopy and UV absorption spectroscopy indicated the complex interacted with ct-DNA in a groove binding mode while the binding constant of UV-vis and the number of binding sites were 1.0±0.2×10 4 Lmol -1 and 1.01, respectively. The fluorometric studies showed that the reaction between the complex with ct-DNA is exothermic (ΔH=14.85kJmol -1 ; ΔS=109.54Jmol -1 K -1 ). Circular dichroism spectroscopy (CD) was employed to measure the conformational change of DNA in the presence of [CuL(NO 3 ) 2 ] complex. Furthermore, the complex induces detectable changes in the viscosity of DNA. The molecular modeling results illustrated that the complex strongly binds to groove of DNA. Experimental and molecular modeling results showed that Cu(II) complex bound to DNA by a groove binding mode. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Synthesis, Crystal Structure, Stacking Effect and Antibacterial Studies of a Novel Quaternary Copper (II Complex with Quinolone

    Directory of Open Access Journals (Sweden)

    Longguan Zhu

    2003-02-01

    Full Text Available The structural properties of a new copper (II complex [Cu2(cip2(bpy2(pip]·6H2O (bpy=2,2’-bipyridyl, cip=1-cyclopropyl-6-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, pip= piperazinyl anion, obtained during the synthesis of the copper complex with ciprofloxacin (cpf, has been investigated. The complex crystallizes in the triclinic system, space group P-1. The cell dimensions are: a=6.874(2 Å, b= 10.761(3 Å, c= 17.969(5 Å, α =80.071(6°, β= 85.253(6°, γ=79.109(6°,V=1284.5(6 Å3, and Z=2. The Cu (II ion displays a five-coordinate square pyramidal coordination with two nitrogen donors from bpy, the 4-keto and 3-carboxylate oxygen donors of cip, and the third nitrogen atom of the pip anion occupying the fifth site. There is a stack effect between cip ring and bpy ring from another molecule, where the stacking distance is about 3.5 Å. The results of elemental analysis and FT-IR measurement are also included. Both ligand and complex were assayed against gram-positive and gram-negative bacteria by the doubling dilutions method. The complex shows the same minimal inhibitory concentration (MIC against S. Aureus and E. Coli bacteria as the corresponding ligand.

  20. Characterisation of the interactions between substrate, copper(II) complex and DNA and their role in rate acceleration in DNA-based asymmetric catalysis.

    Science.gov (United States)

    Draksharapu, Apparao; Boersma, Arnold J; Browne, Wesley R; Roelfes, Gerard

    2015-02-28

    Interactions of the azachalcone derived substrate Aza with copper(II) complexes in the presence and absence of st-DNA were studied in detail by UV/Vis absorption, EPR and Raman and (UV and vis) resonance Raman spectroscopies. The binding of Aza to the Lewis acidic copper(II) complexes, which results in activation of the substrate, was established spectroscopically. It was shown that the binding of Aza differs between Cu(II)dmbpy and Cu(II)terpy, consistent with the observed differences in catalytic asymmetric Diels-Alder reactions with regard to both the rate and enantiomeric preference. Finally, it was shown that DNA has a major beneficial effect on the binding of Aza to the copper(II) complex due to the fact that both bind to the DNA. The result is a high effective molarity of both the copper complexes and the Aza substrate, which leads to a significant increase in binding of Aza to the copper(II) complex. This effect is a key reason for the observed rate acceleration in the catalyzed reactions brought about by the presence of DNA.

  1. Extended X-ray absorption fine structure study of mixed-ligand copper(II) complexes having analogous structures

    Science.gov (United States)

    Gaur, Abhijeet; Shrivastava, B. D.; Srivastava, Krishna; Prasad, J.

    2013-02-01

    X-ray absorption fine structure spectra have been studied at the Cu K-edge in five mixed-ligand copper(II) complexes, viz., [Cu(L-glu)(bipy)] 1, [Cu(L-glu)(phen) (H2O)].3H2O 2, [Cu(L-tyro)(bipy)(ClO4)].2H2O 3, [Cu(L-phen)(bipy)(H2O)] (ClO4) 4, and [Cu(L-tyro)(phen)(H2O)] (ClO4).1.5H2O 5 (where L-glu = L-glutamate dianion, L-tyro = L-tyrosinate anion, bipy = 2,2'-bipyridine, and phen =1,10-phenanthroline), having essentially the same structure. The crystallographic data are available for all the complexes using which five theoretical models have been generated. Firstly, extended X-ray absorption fine structure (EXAFS) data of each complex has been analyzed using its own theoretical model and the results obtained are found to be comparable with the crystallographic results. Then, the EXAFS data of each complex has been analyzed using the theoretical models of the remaining four of these complexes. For each complex, the structural parameters obtained by fitting EXAFS data with theoretical models of the four remaining complexes have been found to be comparable with those obtained by fitting its own theoretical model. Thus, it has been found that if the crystal structure is not available for a complex, then the crystal structure of similar or analogous complex can be used satisfactorily for generating the theoretical model for the EXAFS data analysis of that complex, even if different ligands are attached to the central metal atom. On the basis of EXAFS data analysis, the coordination geometries around the central metal ions in these complexes have been depicted.

  2. Synthesis, crystal structure and biological evaluation of a new dasatinib copper(II) complex as telomerase inhibitor.

    Science.gov (United States)

    Qin, Qi-Pin; Meng, Ting; Tan, Ming-Xiong; Liu, Yan-Cheng; Luo, Xu-Jian; Zou, Bi-Qun; Liang, Hong

    2018-01-01

    A new copper(II) complex of dasatinib (DAS) was synthesized and characterized via ESI-MS, UV-Vis, IR, single-crystal X-ray diffraction analysis, 1 H and 13 C NMR spectroscopy, and elemental analysis. The composition of the new complex (1) was found to be [Cu(DAS + H)(NO 3 ) 2 (H 2 O)]NO 3 ·(H 2 O)·(CH 3 OH). Through MTT assay, it was found that 1 had high cytotoxicity towards A549, HeLa, BEL-7402, Hep-G2, NCI-H460, and MGC80-3 tumor cell lines, with IC 50 values in 4.04-13.04 μM. The Hep-G2 cells were the most sensitive to 1. It is worth noting that compared with DAS and cisplatin, 1 not only had higher in vitro anticancer activity but also exhibited greater selective toxicity towards Hep-G2 cells than for normal HL-7702 cells. Experimental results from cell apoptosis analysis, cellular uptake, TRAP-silver staining assay, RT-PCR, western blot, and transfection assays showed that 1 was most likely a telomerase inhibitor that targeted c-myc G-quadruplex DNA. The high cytotoxicity and biological behaviors of 1 could be correlated with the central copper(II) atom in the coordinated mode with DAS. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Intercalative interaction of asymmetric copper(II) complex with DNA: experimental, molecular docking, molecular dynamics and TDDFT studies.

    Science.gov (United States)

    Hu, Wei; Deng, Suwen; Huang, Jianyin; Lu, Yanmei; Le, Xueyi; Zheng, Wenxu

    2013-10-01

    The intercalative interactions of small molecules with DNA are important in a variety of biological processes including mutagenesis, carcinogenesis, and chemotherapy. A comprehensive research protocol including experiments and calculations was employed to investigate the intercalative interaction between metallointercalator copper(II) complex and DNA. The intercalative binding mode has been validated by UV spectra, fluorescence spectra, CD spectra and viscosity measurements. The classical molecular dynamics simulation was carried out to investigate the intercalative interaction between asymmetric copper(II) complex and DNA. An analytical method was proposed to simulate the dynamically changing absorption spectra of intercalator/DNA system. According to the established model, the changing process of the electronic absorption spectra for intercalator/DNA system can be predicted accurately. A rational explanation for the change law of absorption spectra has been proposed. Moreover, the analyses of the frontier orbital reveal that the red shift of the absorption spectra is due to the increase of π orbital energy caused by the coupling of the π orbital of the intercalated ligand with the π orbital of DNA. This cause of red shift of spectra is completely different from the previous inference. All these insights are of crucial importance for correctly analyzing the absorption spectra of intercalative interaction, as well as for explaining the macroscopic phenomena observed in experiments at the molecular level. © 2013.

  4. A Nanostructured Lipid System as a Strategy to Improve the in Vitro Antibacterial Activity of Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Patricia B. da Silva

    2015-12-01

    Full Text Available The aim of this study was to construct a nanostructured lipid system as a strategy to improve the in vitro antibacterial activity of copper(II complexes. New compounds with the general formulae [CuX2(INH2]·nH2O (X = Cl− and n = 1 (1; X = NCS− and n = 5 (2; X = NCO− and n = 4 (3; INH = isoniazid, a drug widely used to treat tuberculosis derived from the reaction between the copper(II chloride and isoniazid in the presence or absence of pseudohalide ions (NCS− or NCO− were synthesized and characterized by infrared spectrometry, electronic absorption spectroscopy, electron paramagnetic resonance (EPR spectroscopy, elemental analysis, melting points and complexometry with 2,2′,2′′,2′′′-(Ethane-1,2-diyldinitrilotetraacetic acid (EDTA. The characterization techniques allowed us to confirm the formation of the copper(II complexes. The Cu(II complexes were loaded into microemulsion (MEs composed of 10% phase oil (cholesterol, 10% surfactant [soy oleate and Brij® 58 (1:2] and 80% aqueous phase (phosphate buffer pH = 7.4 prepared by sonication. The Cu(II complex-loaded MEs displayed sizes ranging from 158.0 ± 1.060 to 212.6 ± 1.539 nm, whereas the polydispersity index (PDI ranged from 0.218 ± 0.007 to 0.284 ± 0.034. The antibacterial activity of the free compounds and those that were loaded into the MEs against Staphylococcus aureus ATCC® 25923 and Escherichia coli ATCC® 25922, as evaluated by a microdilution technique, and the cytotoxicity index (IC50 against the Vero cell line (ATCC® CCL-81TM were used to calculate the selectivity index (SI. Among the free compounds, only compound 2 (MIC 500 μg/mL showed activity for S. aureus. After loading the compounds into the MEs, the antibacterial activity of compounds 1, 2 and 3 was significantly increased against E. coli (MIC’s 125, 125 and 500 μg/mL, respectively and S. aureus (MICs 250, 500 and 125 μg/mL, respectively. The loaded compounds were less toxic against the Vero

  5. Synthesis, spectroscopic characterization and antimicrobial activity of binuclear metal complexes of a new asymmetrical Schiff base ligand: DNA binding affinity of copper(II) complexes.

    Science.gov (United States)

    Shebl, Magdy

    2014-01-03

    The 1:1 condensation of o-acetoacetylphenol and 1,2-diaminopropane under condition of high dilution gives the mono-condensed Schiff base, (E)-3-(1-aminopropan-2-ylimino)-1-(2-hydroxyphenyl)butan-1-one. The mono-condensed Schiff base has been used for further condensation with isatin to obtain the new asymmetrical dicompartmental Schiff base ligand, (E)-3-(2-((E)-4-(2-hydroxyphenyl)-4-oxobutan-2-ylideneamino) propylimino)indolin-2-one (H3L) with a N2O3 donor set. Reactions of the ligand with metal salts give a series of new binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, (1)H and (13)C NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. The analytical and spectroscopic tools showed that the complexes can be formulated as: [(HL)(VO)2(SO4)(H2O)]·4H2O, [(HL)Fe2Cl4(H2O)3]·EtOH, [(HL)Fe2(ox)Cl2(H2O)3]·2H2O, [(L)M2(OAc)(H2O)m]·nH2O; M=Co, Ni or Cu, m=4, 0 and n=2, 3, [(HL)Cu2Cl]Cl·6H2O and [(L)(UO2)2(OAc)(H2O)3]·6H2O. The metal complexes exhibited octahedral geometrical arrangements except copper complexes that exhibited tetrahedral geometries and uranyl complex in which the metal ion is octa-coordinated. The Schiff base and its metal complexes were evaluated for antimicrobial activity against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli) and fungi (Candida albicans and Aspergillus flavus). The ligand and some of its complexes were found to be biologically active. The DNA-binding properties of the copper complexes (6 and 7) have been investigated by electronic absorption, fluorescence and viscosity measurements. The results obtained indicate that these complexes bind to DNA via an intercalation binding mode with an intrinsic binding constant, Kb of 1.34×10(4) and 2.5×10(4) M(-1), respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Cytotoxic activity, albumin and DNA binding of new copper(II) complexes with chalcone-derived thiosemicarbazones.

    Science.gov (United States)

    Da Silva, Jeferson G; Recio Despaigne, Angel A; Louro, Sonia R W; Bandeira, Cristiano C; Souza-Fagundes, Elaine M; Beraldo, Heloisa

    2013-07-01

    [Cu(HL)Cl2] complexes of chalcone-derived thiosemicarbazones were obtained with 3-phenyl-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCTPh), complex (1), 3-(4-chlorophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4ClPh), complex (2), 3-(4-bromophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4BrPh), complex (3), and 3-(4-nitrophenyl-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4NO2Ph), complex (4). 1-3 showed interaction with bovine serum albumin (BSA) and deoxyribonucleic acid from calf thymus (CT-DNA). The cytotoxic activities of the thiosemicarbazones and complexes (1-4) were tested against HL60 (wild type human promyelocytic leukemia), Jurkat (human immortalized line of T lymphocyte), MDA-MB 231 (human breast carcinoma) and HCT-116 (human colorectal carcinoma) tumor cell lineages. Upon coordination to copper(II) cytotoxicity significantly increased in Jurkat, MDA-MB 231 and HCT-116 cells. Unlike the free thiosemicarbazones, 1-4 induced DNA fragmentation in solid tumor cells indicating their pro-apoptotic potential. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  7. Complexation of the fungal metabolite tenuazonic acid with copper (II), iron (III), nickel (II), and magnesium (II) ions.

    Science.gov (United States)

    Lebrun, M H; Duvert, P; Gaudemer, F; Gaudemer, A; Deballon, C; Boucly, P

    1985-07-01

    Tenuazonic acid (TA) is a phytotoxin produced by a fungal pathogen of rice, Pyricularia oryzae. We have synthesized and characterized the metal complexes of TA with copper (II), iron (III), nickel (II), and magnesium (II). The stoichiometry of the complexes determined by microanalysis and mass spectroscopy (D/CI) are Cu(II)TA2, Fe(III)TA3, Ni(II)TA2, and Mg(TA)2. Voltammograms of Fe(III)TA3, and Cu(II)TA2 in methanolic solutions confirmed this stoichiometry. Ni(II)TA2 paramagnetism and visible absorption data suggest an octahedral geometry. Fe(III)TA3 showed a characteristic visible absorption at 450 nm. Addition of Fe(III)Cl3 and Mg(II)Cl2 did not reverse the toxicity of NaTA to rice and bacterial cells, showing that this toxicity is not due to the privation of the cells of these metals essential for cell growth.

  8. Synthesis, X-ray crystal structures, electrochemistry and theoretical investigation of a tetradentate nickel and copper Schiff base complexes

    Science.gov (United States)

    Rahmouni, Samra; Djedouani, Amel; Anak, Barkahem; Tabti, Salima; Bendaas, Abderrahmen; Bencharif, Mustapha; François, Michel; Fleutot, Solenne; Rabilloud, Franck

    2017-11-01

    New tetradentate mononuclear nickel(II) [NiL] and pentadentate binuclear copper(II) [Cu2L2H2O], H2O Schiff base complexes have been synthesized. The crystal structures of [NiL] and [Cu2L2H2O], H2O have been determined by X-ray diffraction method showing distorted square-planar geometry for [NiL] and distorted tetragonal pyramid geometry for [Cu2L2H2O], H2O. In both complexes, the dehydroacetic acid functional group engages in a deprotonated manner and coordination occurs through the nitrogen atoms of the imine function and the phenolic oxygen. Density Functional Theory calculations are carried out for the determination of the optimized structures. The fundamental vibrational wave numbers are calculated and a good agreement between observed and calculated wave numbers is achieved.

  9. Copper(II) Complexes of Phenanthroline and Histidine Containing Ligands: Synthesis, Characterization and Evaluation of their DNA Cleavage and Cytotoxic Activity.

    Science.gov (United States)

    Leite, Sílvia M G; Lima, Luís M P; Gama, Sofia; Mendes, Filipa; Orio, Maylis; Bento, Isabel; Paulo, António; Delgado, Rita; Iranzo, Olga

    2016-11-21

    Copper(II) complexes have been intensely investigated in a variety of diseases and pathological conditions due to their therapeutic potential. The development of these complexes requires a good knowledge of metal coordination chemistry and ligand design to control species distribution in solution and tailor the copper(II) centers in the right environment for the desired biological activity. Herein we present the synthesis and characterization of two ligands HL1 and H 2 L2 containing a phenanthroline unit (phen) attached to the amino group of histidine (His). Their copper(II) coordination properties were studied using potentiometry, spectroscopy techniques (UV-vis and EPR), mass spectrometry (ESI-MS) and DFT calculations. The data showed the formation of single copper complexes, [CuL1] + and [CuL2], with high stability within a large pH range (from 3.0 to 9.0 for [CuL1] + and from 4.5 to 10.0 for [CuL2]). In both complexes the Cu 2+ ion is bound to the phen unit, the imidazole ring and the deprotonated amide group, and displays a distorted square pyramidal geometry as confirmed by single crystal X-ray crystallography. Interestingly, despite having similar structures, these copper complexes show different redox potentials, DNA cleavage properties and cytotoxic activity against different cancer cell lines (human ovarian (A2780), its cisplatin-resistant variant (A2780cisR) and human breast (MCF7) cancer cell lines). The [CuL2] complex has lower reduction potential (E pc = -0.722 V vs -0.452 V for [CuL1] + ) but higher biological activity. These results highlight the effect of different pendant functional groups (carboxylate vs amide), placed out of the coordination sphere, in the properties of these copper complexes.

  10. Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA.

    Science.gov (United States)

    Jones, Daniel S; Lapakko, Kim A; Wenz, Zachary J; Olson, Michael C; Roepke, Elizabeth W; Sadowsky, Michael J; Novak, Paige J; Bailey, Jake V

    2017-08-15

    The Duluth Complex in northeastern Minnesota hosts economically significant deposits of copper, nickel, and platinum group elements (PGEs). The primary sulfide mineralogy of these deposits includes the minerals pyrrhotite, chalcopyrite, pentlandite, and cubanite, and weathering experiments show that most sulfide-bearing rock from the Duluth Complex generates moderately acidic leachate (pH 4 to 6). Microorganisms are important catalysts for metal sulfide oxidation and could influence the quality of water from mines in the Duluth Complex. Nevertheless, compared with that of extremely acidic environments, much less is known about the microbial ecology of moderately acidic sulfide-bearing mine waste, and so existing information may have little relevance to those microorganisms catalyzing oxidation reactions in the Duluth Complex. Here, we characterized the microbial communities in decade-long weathering experiments (kinetic tests) conducted on crushed rock and tailings from the Duluth Complex. Analyses of 16S rRNA genes and transcripts showed that differences among microbial communities correspond to pH, rock type, and experimental treatment. Moreover, microbial communities from the weathered Duluth Complex rock were dominated by taxa that are not typically associated with acidic mine waste. The most abundant operational taxonomic units (OTUs) were from the genera Meiothermus and Sulfuriferula, as well as from diverse clades of uncultivated Chloroflexi, Acidobacteria, and Betaproteobacteria Specific taxa, including putative sulfur-oxidizing Sulfuriferula spp., appeared to be primarily associated with Duluth Complex rock, but not pyrite-bearing rocks subjected to the same experimental treatment. We discuss the implications of these results for the microbial ecology of moderately acidic mine waste with low sulfide content, as well as for kinetic testing of mine waste.IMPORTANCE Economic sulfide mineral deposits in the Duluth Complex may represent the largest undeveloped

  11. Ionic liquids as a key medium for efficient extraction of copper complexes from chia seeds (Salvia hispanica L.).

    Science.gov (United States)

    Wojcieszek, Justyna; Popowski, Dominik; Ruzik, Lena

    2016-05-15

    Due to insufficient information, the aim of study was to concern on the optimization of extraction procedure of selected metal complexes with flavonoids from chia seeds. Evaluation of the amount of elements in compound, not only their total concentration content, is highly important due to the fact, that only a part from total content of metal is absorbed by human body. At the beginning the total amount of elements in chia seeds was established as 14.51±0.42 µg g(-1) for copper, 57.44±1.23 µg g(-1) for manganese, 81.12±1.89 µg g(-1) for zinc and 0.35±0.13 µg g(-1) for cobalt. After the most suitable solvent was established, effects of several parameters on the efficiency of metal extraction were studied. Solvent concentration, solid-solvent ratio, extraction method, extraction time and temperature have been investigated as independent variables. The optimal extraction conditions included vortexing during 20 min in 50°C, using an ionic liquid (1-butyl-3-methylimidazolium bromide) as an extractant, with solid-solvent ratio of 1:20. The determination of total and extractable amount of metals in chia seeds was carried out by standalone ICP MS. In addition, a complementary analysis of extracted metal complexes was performed using SEC-ICP MS method. It was confirmed that the ionic liquid is able to extract different copper complexes in comparison with commonly used solvents. The study indicated that extraction by using an ionic liquid has been successfully applied for determination of metals and metal complexes in chia seeds. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Synthesis of mononuclear copper(II) complexes of acyclic Schiff's base ligands: spectral, structural, electrochemical, antibacterial, DNA binding and cleavage activity.

    Science.gov (United States)

    Jayamani, Arumugam; Thamilarasan, Vijayan; Sengottuvelan, Nallathambi; Manisankar, Paramasivam; Kang, Sung Kwon; Kim, Young-Inn; Ganesan, Vengatesan

    2014-03-25

    The mononuclear copper(II) complexes (1&2) of ligands L(1) [N,N'-bis(2-hydroxy-5-methylbenzyl)-1,4-bis(3-iminopropyl)piperazine] or L(2) [N,N'-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl) piperazine] have been synthesized and characterised. The single crystal X-ray study had shown that ligands L(1) and L(2) crystallize in a monoclinic crystal system with P21/c space group. The mononuclear copper(II) complexes show one quasireversible cyclic voltammetric response near cathodic region (-0.77 to -0.85 V) in DMF assignable to the Cu(II)/Cu(I) couple. Binding interaction of the complexes with calf thymus DNA (CT DNA) investigated by absorption studies and fluorescence spectral studies show good binding affinity to CT DNA, which imply both the copper(II) complexes can strongly interact with DNA efficiently. The copper(II) complexes showed efficient oxidative cleavage of plasmid pBR322 DNA in the presence of 3-mercaptopropionic acid as reducing agent through a mechanistic pathway involving formation of singlet oxygen as the reactive species. The Schiff bases and their Cu(II) complexes have been screened for antibacterial activities which indicates that the complexes exhibited higher antimicrobial activity than the free ligands. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Synthesis of mononuclear copper(II) complexes of acyclic Schiff's base ligands: Spectral, structural, electrochemical, antibacterial, DNA binding and cleavage activity

    Science.gov (United States)

    Jayamani, Arumugam; Thamilarasan, Vijayan; Sengottuvelan, Nallathambi; Manisankar, Paramasivam; Kang, Sung Kwon; Kim, Young-Inn; Ganesan, Vengatesan

    2014-03-01

    The mononuclear copper(II) complexes (1&2) of ligands L1 [N,N";-bis(2-hydroxy-5-methylbenzyl)-1,4-bis(3-iminopropyl)piperazine] or L2 [N,N";-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl) piperazine] have been synthesized and characterised. The single crystal X-ray study had shown that ligands L1 and L2 crystallize in a monoclinic crystal system with P21/c space group. The mononuclear copper(II) complexes show one quasireversible cyclic voltammetric response near cathodic region (-0.77 to -0.85 V) in DMF assignable to the Cu(II)/Cu(I) couple. Binding interaction of the complexes with calf thymus DNA (CT DNA) investigated by absorption studies and fluorescence spectral studies show good binding affinity to CT DNA, which imply both the copper(II) complexes can strongly interact with DNA efficiently. The copper(II) complexes showed efficient oxidative cleavage of plasmid pBR322 DNA in the presence of 3-mercaptopropionic acid as reducing agent through a mechanistic pathway involving formation of singlet oxygen as the reactive species. The Schiff bases and their Cu(II) complexes have been screened for antibacterial activities which indicates that the complexes exhibited higher antimicrobial activity than the free ligands.

  14. Wet-chemical preparation of copper foam monoliths with tunable densities and complex macroscopic shapes.

    Science.gov (United States)

    Kränzlin, Niklaus; Niederberger, Markus

    2013-10-18

    Macroscopic monoliths of copper foams have been prepared by a template-assisted wet-chemical process. The method offers subtle control over the pore size and size distribution, density and macroscopic size and shape of the metal foam. Uniaxial compression tests revealed different deformation behavior depending on the relative density. Non-vacuum-based and low-temperature routes are attractive for the cost-effective production of metal foams. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Synthesis, crystal structure and magnetic studies of tetranuclear hydroxo and ligand bridged [Co4(μ3-OH)2(μ2-dea)2(L-L)4]4Cl·8H2O [L-L = 2,2'-bipyridine or 1,10-phenanthroline] complexes with mixed valence defect dicubane core.

    Science.gov (United States)

    Siddiqi, Zafar A; Siddique, Armeen; Shahid, M; Khalid, Mohd; Sharma, Prashant K; Anjuli; Ahmad, Musheer; Kumar, Sarvendra; Lan, Yanhua; Powell, Annie K

    2013-07-14

    X-ray crystallography of the title complexes indicates a discrete mixed valence (Co2(II)-Co2(III)) defect dicubane molecular unit where each cobalt nucleus attains a distorted octahedral geometry. The α-diimine (L-L) chelator coordinated to each cobalt ion stops further polymerization or nuclearization. The water molecules in the lattice play a crucial role in the formation of the supramolecular architectures. Magnetic data were analyzed using the effective spin-1/2 Hamiltonian approach and the parameters are, J = 115(6) K, ΔJ = -57.0(1.2) K, g(xy) = 3.001(25), and g(z) = 7.214(7) for 1 and J = 115(12) K, ΔJ = -58.5(2.5) K, g(xy) = 3.34(5), and g(z) = 6.599(12) for 2 suggesting that only the g matrices are prone to the change of α-diimine chelator.

  16. DNA binding and gel electrophoresis studies of a copper (II) complex containing mixed aliphatic and aromatic dinitrogen ligands.

    Science.gov (United States)

    Shahabadi, Nahid; Darabi, Farivash; Maghsudi, Maryam; Kashanian, Soheila

    2010-06-01

    The interaction of a novel mixed ligand copper (II) complex, [Cu(N-N)(L)(EtOH)](NO(3))(2) . 2H(2)O, in which N-N indicates 2,9-dimethyl-1,10-phenanthroline and L indicates N,N-dimethyltrimethylenediamine with calf thymus DNA was investigated by absorption, circular dichroism, voltammetric, and viscosimetric techniques. The absorption spectra of the complex with calf thymus DNA showed a marked hypochromism in the pi --> pi* and metal to ligand charge transfer (MLCT) transitions, with no obvious red shift attributed to a partial intercalation. The intrinsic binding constant (K(b)) was determined as 2 x 10(5) M(-1). There was slight to appreciable changes in the relative viscosity of DNA, which is consistent with enhanced hydrophobic interaction of the methyl-substituted phen ring and partial intercalation mode of binding. Electrochemical studies showed a decrease in the peak current, which is ascribed to the strong binding between Cu (II) complex and DNA. The fluorescence spectral characteristics showed that the Cu (II) complex is able to displace the methylene blue bound to DNA, but not as complete as intercalative molecules. It is remarkable that this mixed ligand complex, in contrast to [Cu(2,9-dmp)(2)](+) (2,9-dmp = 2,9-dimethyl-1,10-phenanthroline), which fails to cleave DNA, has ability to cleave the supercoiled plasmid DNA.

  17. Synthesis, Characterization, and Cytotoxic Activities of a Schiff Base Ligand and Its Binuclear Copper(II and Manganese(III Complexes

    Directory of Open Access Journals (Sweden)

    Zafer Uyar

    2017-09-01

    Full Text Available A novel symmetrical N2O2 type Schiff base (1 and its copper (II (2 and manganese (III (3 complexes were synthesized and characterized by spectroscopic, analytical, and magnetic susceptibility studies. Spectroscopic and magnetic susceptibility studies suggested that copper and manganese ions are in 2+ and 3+ states and their complexes have a binuclear double stranded helical structure in the form of 2:2 (metal to ligand stoichiometry. Cytotoxic effects of the ligand and its metal complexes against MCF-7 (human breast cancer cell line, DLD-1 (human colorectal cancer cell line, ECC-1 (human endometrium cancer cell line, DU-145 (human prostate cancer line, MDA-MB231 (human breast cancer cell line, PC-3 (human prostate cancer line and HEK293 (normal cells were evaluated by determining their cellular viability using the colorimetric 3-(4,5- dimethylthiazole-2-yl-2,5-biphenyl tetrazolium bromide (MTT assay. It has been found that cytotoxicity of the ligand was significantly enhanced towards cancer cells and declined towards normal HEK293 cells by metal chelation. Copper complex yielded better results in comparison with manganese complex. Particularly, copper complex showed a selective cytotoxicity, harming the cancerous cell lines while not impairing the normal cells, which is considered as the key to the future of cytotoxic therapy.

  18. Synthesis, spectra and crystal structure of 2-(?[3-(methyl?3-[(2-hydroxybenzylidene)amino]propyl? amino)propyl]imino?methyl)phenol copper(II) complex

    Science.gov (United States)

    Yilmaz, Veysel T.; Degirmencioglu, Ismail; Andac, Omer; Karabocek, Serdar; Slawin, Alexandra M. Z.

    2003-06-01

    A copper(II) complex, [Cu(salenN3], [salenN3H2=2-({[3-(methyl{3-[(2-hydroxybenzylidene)amino]propyl}amino)propyl]imino}methyl)phenol] was synthesized and characterized by elemental analyses, FTIR spectra and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space group P21/ c with a=6.877(3), b=14.109(6), c=20.106(8) Å, β=92.231(14)°, V=1949.5(14) Å 3. The salen ligand loses two phenolic hydrogens being a dianion and coordinates to the copper(II) ion as a pentadentate ligand through its two O and three N atoms. The copper(II) complex is five-coordinate, lying between perfect square pyramidal and trigonal-bipyramidal extremes. Use of the structural index parameter ( τ) for five coordinate metal complexes indicated that the copper(II) complex exhibits a grater tendency toward trigonal-based-pyramidal geometry ( τ>0.5). The individual molecules in the crystal are held together by C-H⋯π and H⋯H interactions. The IR and electronic spectra of the complex were discussed in detail.

  19. Synthesis and Structure of a Ternary Copper(II) Complex with Mixed Ligands of Diethylenetriamine and Picrate: DNA/Protein-Binding Property and In Vitro Anticancer Activity Studies.

    Science.gov (United States)

    Shi, Ya-Ning; Zheng, Kang; Zhu, Ling; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2015-05-01

    Based on the importance of the design and synthesis of transition metal complexes with noncovalent DNA/protein-binding abilities in the field of metallo pharmaceuticals, a new mononuclear ternary copper(II) complex with mixed ligands of diethylenetriamine (dien) and picrate anion (pic), identified as [Cu(dien)(pic)](pic), was synthesized and characterized by elemental analysis, molar conductivity measurement, infrared spectrum, electronic spectral studies, and single-crystal X-ray diffractometry. The structure analysis reveals that the copper(II) complex crystallizes in the monoclinic space group P21 /c, and the copper(II) ion has a distorted square pyramidal coordination geometry. A two-dimensional supramolecular structure is formed through hydrogen bonds. The DNA/bovine serum albumin (BSA)-binding properties of the complex are explored, indicating that the complex can interact with herring sperm DNA via intercalation mode and bind to BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism. The in vitro anticancer activity shows that the copper(II) complex is active against the selected tumor cell lines. © 2015 Wiley Periodicals, Inc.

  20. EVALUATION OF APPLICATION OF COAGULANTS CONTAINING DIVALENT AND TRIVALENT IRON TO ENHANCE REMOVAL OF ORGANIC COMPOUNDS AND COMPLEXED COPPER AND TIN IONS FROM INDUSTRIAL EFFLUENTS

    Directory of Open Access Journals (Sweden)

    Maciej Thomas

    2014-10-01

    Full Text Available The article presents the issues concerning physical and chemical parameters of raw sewage from the production of printed circuit boards and the composition of the bath used technology in terms of meeting the requirements for the introduction of treated wastewater into surface waters, ground or the municipal sewage system. Showed test results for the removal of organic compounds and ions complexed copper (II and tin (II and (IV using coagulants containing ions of Fe (II and Fe (III. The studies showed the high efficiency of removal of organic compounds and tin compounds. Explained the possible causes of the difficulties of precipitation complexed copper ions (II.

  1. Molecular trail for the anticancer behavior of a novel copper carbohydrazone complex in BRCA1 mutated breast cancer.

    Science.gov (United States)

    Nair, Rakesh Sathish; Potti, Manoj Easwaran; Thankappan, Ratheeshkumar; Chandrika, Sivakumar Krishnankutty; Kurup, M R Prathapachandra; Srinivas, Priya

    2017-05-01

    Novel chelated metal complexes were synthesized from carbohydrazones to thiocarbohydrazones using metal-based drug designing platforms and their combination effect with Pb, a naphthaquinone were analyzed for anticancer activity in breast cancer cell lines. A panel of BRCA1 wild-type and mutated breast cancer cells: MCF-7 (BRCA1 + /ER + ), MDA-MB-231 (BRCA1 + /ERα - ), HCC-1937 (BRCA1 - /ERα - ), HCC1937/wt BRCA1, MX1 (BRCA1 - /ERα - ), and MDA-MB-436 (BRCA1 - /ERα - ) were screened for anti-cancer activity. Cu 2 (HL)(HSO 4 ) · H 2 O]SO 4  · 6 H 2 O (CS2) is the most potent anticancer agent among the copper carbohydrazone and thiocarbohydrazone complexes analyzed in this study. It can be suggested that the presence of sulphate, as pharmacologically active centre, can induce cytotoxicity more effectively when compared to chlorine, bromine, perchlorate, and methanol. This is the first report demonstrating that CS2 can bind to DNA by hindering BamH1 activity and could induce DNA double strand breaks as evidenced by γ-H2AX expression. In addition to this, CS2 could also act as a Topo II inhibitor at a much lower concentration than etoposide and induce apoptosis, making it a potent anticancer agent. In combination with Pb, a potent ROS inducer, CS2 could induce synergistic anti-cancer activity in HR/ BRCA1 defective breast cancer cells. This is the first study reporting the mechanism involved in the induction of apoptosis for a metal chelated copper carbohydrazone complex and its combination effects with Pb in HR defective, BRCA1 mutated breast cancer cells. © 2017 Wiley Periodicals, Inc.

  2. Synthesis, spectroscopic characterisation, thermal analysis, DNA interaction and antibacterial activity of copper(I) complexes with N, N‧- disubstituted thiourea

    Science.gov (United States)

    Chetana, P. R.; Srinatha, B. S.; Somashekar, M. N.; Policegoudra, R. S.

    2016-02-01

    copper(I) complexes [Cu(4MTU)2Cl] (2), [Cu(4MTU) (B)Cl] (3), [Cu(6MTU)2Cl] (5) and [Cu(6MTU) (B)Cl] (6) where 4MTU = 1-Benzyl-3-(4-methyl-pyridin-2-yl)-thiourea (1) and 6MTU = 1-Benzyl-3-(6-methyl-pyridin-2-yl)-thiourea (4), B is a N,N-donor heterocyclic base, viz. 1,10-phenanthroline (phen 3, 6), were synthesized, characterized by various physico-chemical and spectroscopic techniques. The elemental analysis suggests that the stoichiometry to be 1:2 (metal:ligand) for 2, 5 1:1:1 (metal:ligand:B) for 3, 6. X-ray powder diffraction illustrates that the complexes have crystalline nature. IR data coupled with electronic spectra and molar conductance values suggest that the complex 2, 5 show the presence of a trigonal planar geometry and the complex 3, 6 show the presence of a tetrahedral geometry about the Cu(I) centre. The binding affinity towards calf thymus (CT) DNA was determined using UV-Vis, fluorescence spectroscopic titrations and viscosity studies. These studies showed that the tested phen complexes 3, 6 bind moderately (in the order of 105 M-1) to CT DNA. The complex 2, 5 does not show any apparent binding to the DNA and hence poor cleavage efficiency. Complex 3, 6 shows efficient oxidative cleavage of plasmid DNA in the presence of H2O2 involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and KI. The in vitro antibacterial assay indicates that these complexes are good antimicrobial agents against various pathogens. Anti-bacterial activity is higher when thiourea coordinates to metal ion than the thiourea alone.

  3. Spectroscopy of Bioactive Manganese(II) and Copper(II) Complexes with Mannich Bases

    Science.gov (United States)

    Harbatsevich, H. I.; Loginova, N. V.; Koval‧chuk, T. V.; Osipovich, N. P.; Gres, A. T.; Azarko, I. I.; Polozov, G. I.

    2015-11-01

    The compositions and geometries of coordination polyhedra in Cu(II) and Mn(II) complexes with Mannich bases were determined using IR, EPR, and electron spectroscopy. It was shown that bidentate ligands were coordinated to the metal ions in these complexes. The coordination polyhedra of mononuclear Cu(II) and Mn(II) complexes consisted of two mono-anionic ligands. Polyhedra of the Mn(II) complexes also contained two water molecules. The Cu(II) complexes had characteristic square-planar [CuN2O2] coordination polyhedra; Mn(II) complexes, [MnN2O4] octahedra.

  4. Synthesis of copper and zinc 2-(pyridin-2-yl)imidazo[1,2-a]pyridine complexes and their potential anticancer activity.

    Science.gov (United States)

    Dam, Jean; Ismail, Zeenat; Kurebwa, Taurai; Gangat, Nadia; Harmse, Leonie; Marques, Helder M; Lemmerer, Andreas; Bode, Moira L; de Koning, Charles B

    2017-01-27

    A small library of novel copper and zinc imidazo[1,2-a]pyridine complexes have been synthesized. Their structures were confirmed by X-ray diffraction crystallography and a selection of these compounds was tested against five cancer cell lines originating from breast cancer (MCF-7 and MDA-MB-231), leukemia (K562 and HL-60) and colorectal cancer (HT-29). The imidazo[1,2-a]pyridines and their zinc complexes showed poor anticancer activity, while the copper complexes were active against the cancer cell lines with IC50 values comparable to and lower than camptothecin. For example, copper 6-bromo-N-cyclohexyl-2-(pyridin-2-yl)imidazo[1,2-a]pyridin-3-amine acetate 21 had an IC50 value lower than 1 μM against the HT-29 cells. Fluorescence microscopy with acridine orange, Hoechst 33342 and ethidium bromide, used in a preliminary investigation to evaluate morphological changes showed that copper 6-bromo-N-cyclohexyl-2-(pyridin-2-yl)imidazo[1,2-a]pyridin-3-amine acetate 21 caused both apoptosis, necrosis and paraptosis in the MCF-7 and HL-60 cells. A select group of copper N-cyclohexyl-2-(pyridin-2-yl)imidazo[1,2-a]pyridin-3-amines (26, 27, 29 and 31) induced apoptosis, paraptosis and deformed nuclei in MCF-7 cells. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Structurally diverse copper complexes bearing NNO-tridentate Schiff-base derivatives as efficient catalysts for copolymerization of carbon dioxide and cyclohexene oxide.

    Science.gov (United States)

    Tsai, Chen-Yen; Huang, Bor-Hunn; Hsiao, Mon-Wei; Lin, Chu-Chieh; Ko, Bao-Tsan

    2014-05-19

    Structurally diverse copper acetate complexes based on NNO-tridentate Schiff-base ligands were synthesized and characterized as mono-, di-, and trinuclear complexes with respect to varied ancillary ligands. Treatment of the ligand precursors (L(1)-H = 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-4-methylphenol, L(2)-H = 4-chloro-2-(1-((2-(dimethylamino)ethyl)imino)ethyl)phenol, and L(3)-H = 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-5-methylphenol) with Cu(OAc)2·H2O (1 equiv) in refluxing ethanol afforded five-coordinate mono- or bimetallic copper complexes ([(L(1))Cu(OAc)(H2O)] (1); [(L(2))Cu(OAc)(H2O)] (2); [(L(3))2Cu2(OAc)2] (3)) in high yields. Dinuclear copper acetate analogue [(L(1))2Cu2(OAc)2] (4) resulted from treatment of L(1)-H as the ligand precursor in refluxing anhydrous MeOH with equimolar proportions of metal acetate salt under a dry nitrogen atmosphere. However, a trinuclear complex, [(L(4))2Cu3(OAc)4] (5), was obtained on utilizing 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-5-methoxyphenol (L(4)-H) as the proligand under the same synthetic route of 1-3; this complex was also synthesized in the reaction of L(4)-H and copper(II) acetate monohydrate in the ratio of 2:3, giving a quantitative yield. All complexes are active catalysts for copolymerization of cyclohexene oxide (CHO) and CO2 without cocatalysts. In particular, dinuclear Cu complex 3 performed satisfactorily to produce polycarbonates with controllable molecular weights and high carbonate linkages. These copper complexes are the first examples that are effective for both CO2/CHO copolymerization and formation of polymers in a controlled fashion.

  6. Simple Copper(II) Schiff Base Complex as Efficient Heterogeneous Photo-Fenton-like Catalyst

    National Research Council Canada - National Science Library

    Fei, Bao-Li; Wang, Jiang-Hong; Yan, Qing-Ling; Liu, Qing-Bo; Long, Jian-Ying; Li, Yang-Guang; Shao, Kui-Zhan; Su, Zhong-Min; Sun, Wei-Yin

    2014-01-01

    ...) as photo-Fenton-like catalysts. Both 1 and 2 exhibited excellent catalytic performance without an acidification process, and the mononuclear complex 2 functioned better than the dinuclear complex 1...

  7. Nickel(II) and copper(II) complexes with humic acid anions and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Ryabova, I.N. [Kazakh Academy of Science, Karaganda (Kazakhstan)

    2008-01-15

    Complexation of Ni(II) and Cu(II) in aqueous solutions with anions of humic acids, extracted from naturally oxidized coal, and with their hydroxymethyl derivatives is studied spectrophotometrically and potentiometrically. The complexation stoichiometry and the stability constants of the complexes are determined.

  8. Biotin Decorated Gold Nanoparticles for Targeted Delivery of a Smart-Linked Anticancer Active Copper Complex: In Vitro and In Vivo Studies.

    Science.gov (United States)

    Pramanik, Anup K; Siddikuzzaman; Palanimuthu, Duraippandi; Somasundaram, Kumaravel; Samuelson, Ashoka G

    2016-12-21

    The synthesis and anticancer activity of a copper(II) diacetyl-bis(N4-methylthiosemicarbazone) complex and its nanoconjugates are reported. The copper(II) complex is connected to a carboxylic acid group through a cleavable disulfide link to enable smart delivery. The copper complex is tethered to highly water-soluble 20 nm gold nanoparticles (AuNPs), stabilized by amine terminated lipoic acid-polyethylene glycol (PEG). The gold nanoparticle carrier was further decorated with biotin to achieve targeted action. The copper complex and the conjugates with and without biotin, were tested against HeLa and HaCaT cells. They show very good anticancer activity against HeLa cells, a cell line derived from cervical cancer and are less active against HaCaT cells. Slow and sustained release of the complex from conjugates is demonstrated through cleavage of disulfide linker in the presence of glutathione (GSH), a reducing agent intrinsically present in high concentrations within cancer cells. Biotin appended conjugates do not show greater activity than conjugates without biotin against HeLa cells. This is consistent with drug uptake studies, which suggests similar uptake profiles for both conjugates in vitro. However, in vivo studies using a HeLa cell xenograft tumor model shows 3.8-fold reduction in tumor volume for the biotin conjugated nanoparticle compared to the control whereas the conjugate without biotin shows only 2.3-fold reduction in the tumor volume suggesting significant targeting.

  9. Structure and spectroscopic properties of the dimeric copper(I) N-heterocyclic carbene complex [Cu₂(CNC(t-Bu))₂](PF₆)₂.

    Science.gov (United States)

    Riener, Korbinian; Pöthig, Alexander; Cokoja, Mirza; Herrmann, Wolfgang A; Kühn, Fritz E

    2015-08-01

    In recent years, the use of copper N-heterocyclic carbene (NHC) complexes has expanded to fields besides catalysis, namely medicinal chemistry and luminescence applications. In the latter case, multinuclear copper NHC compounds have attracted interest, however, the number of these complexes in the literature is still quite limited. Bis[μ-1,3-bis(3-tert-butylimidazolin-2-yliden-1-yl)pyridine]-1κ(4)C(2),N:N,C(2');2κ(4)C(2),N:N,C(2')-dicopper(I) bis(hexafluoridophosphate), [Cu2(C19H25N5)2](PF6)2, is a dimeric copper(I) complex bridged by two CNC, i.e. bis(N-heterocyclic carbene)pyridine, ligands. Each Cu(I) atom is almost linearly coordinated by two NHC ligands and interactions are observed between the pyridine N atoms and the metal centres, while no cuprophilic interactions were observed. Very strong absorption bands are evident in the UV-Vis spectrum at 236 and 274 nm, and an emission band is observed at 450 nm. The reported complex is a new example of a multinuclear copper NHC complex and a member of a compound class which has only rarely been reported.

  10. Fluorescence and electron paramagnetic resonance studies of norfloxacin and N-donor mixed-ligand ternary copper(II) complexes: Stability and interaction with SDS micelles

    Science.gov (United States)

    Vignoli Muniz, Gabriel S.; Incio, Jimmy Llontop; Alves, Odivaldo C.; Krambrock, Klaus; Teixeira, Letícia R.; Louro, Sonia R. W.

    2018-01-01

    The stability of ternary copper(II) complexes of a heterocyclic ligand, L (L being 2,2‧-bipyridine (bipy) or 1,10-phenanthroline (phen)) and the fluorescent antibacterial agent norfloxacin (NFX) as the second ligand was studied at pH 7.4 and different ionic strengths. Fluorescence quenching upon titration of NFX with the binary complexes allowed to obtain stability constants for NFX binding, Kb, as a function of ionic strength. The Kb values vary by more than two orders of magnitude when buffer concentration varies from 0.5 to 100 mM. It was observed that previously synthesized ternary complexes dissociate in buffer according with the obtained stability constants. This shows that equimolar solutions of NFX and binary complexes are equivalent to solutions of synthesized ternary complexes. The interaction of the ternary copper complexes with anionic SDS (sodium dodecyl sulfate) micelles was studied by fluorescence and electron paramagnetic resonance (EPR). Titration of NFX-loaded SDS micelles with the complexes Cu:L allowed to determine the stability constants inside the micelles. Fluorescence quenching demonstrated that SDS micelles increase the stability constants by factors around 50. EPR spectra gave details of the copper(II) local environment, and demonstrated that the structure of the ternary complexes inside SDS micelles is different from that in buffer. Mononuclear ternary complexes formed inside the micelles, while in buffer most ternary complexes are binuclear. The results show that anionic membrane interfaces increase formation of copper fluoroquinolone complexes, which can influence bioavailability, membrane diffusion, and mechanism of action of the antibiotics.

  11. Quantification of creatinine in biological samples based on the pseudoenzyme activity of copper-creatinine complex

    Science.gov (United States)

    Nagaraja, Padmarajaiah; Avinash, Krishnegowda; Shivakumar, Anantharaman; Krishna, Honnur

    Glomerular filtration rate (GFR), the marker of chronic kidney disease can be analyzed by the concentration of cystatin C or creatinine and its clearance in human urine and serum samples. The determination of cystatin C alone as an indicator of GFR does not provide high accuracy, and is more expensive, thus measurement of creatinine has an important role in estimating GFR. We have made an attempt to quantify creatinine based on its pseudoenzyme activity of creatinine in the presence of copper. Creatinine in the presence of copper oxidizes paraphenylenediamine dihydrochloride (PPDD) which couples with dimethylamino benzoicacid (DMAB) giving green colored chromogenic product with maximum absorbance at 710 nm. Kinetic parameters relating this reaction were evaluated. Analytical curves of creatinine by fixed time and rate methods were linear at 8.8-530 μmol L-1 and 0.221-2.65 mmol L-1, respectively. Recovery of creatinine varied from 97.8 to 107.8%. Limit of detection and limit of quantification were 2.55 and 8.52 μmol L-1 respectively whereas Sandell's sensitivity and molar absorption coefficient values were 0.0407 μg cm-2 and 0.1427 × 104 L mol-1 cm-1 respectively. Precision studies showed that within day imprecision was 0.745-1.26% and day-to-day imprecision was 1.55-3.65%. The proposed method was applied to human urine and serum samples and results were validated in accordance with modified Jaffe's procedure. Wide linearity ranges with good recovery, less tolerance from excipients and application of the method to serum and urine samples are the claims which ascertain much advantage to this method.

  12. Low-cost copper complexes as p-dopants in solution processable hole transport layers

    Energy Technology Data Exchange (ETDEWEB)

    Kellermann, Renate [Department for Materials Science and Engineering, Chair for Materials for Electronics and Energy Technology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058 (Germany); Siemens AG – Corporate Technology, Guenther-Scharowsky-Str. 1, Erlangen 91058 (Germany); Taroata, Dan; Maltenberger, Anna; Hartmann, David; Schmid, Guenter [Siemens AG – Corporate Technology, Guenther-Scharowsky-Str. 1, Erlangen 91058 (Germany); Brabec, Christoph J. [Department for Materials Science and Engineering, Chair for Materials for Electronics and Energy Technology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058 (Germany)

    2015-09-07

    We demonstrate the usage of the Lewis-acidic copper(II)hexafluoroacetylacetonate (Cu(hfac){sub 2}) and copper(II)trifluoroacetylacetonate (Cu(tfac){sub 2}) as low-cost p-dopants for conductivity enhancement of solution processable hole transport layers based on small molecules in organic light emitting diodes (OLEDs). The materials were clearly soluble in mixtures of environmentally friendly anisole and xylene and spin-coated under ambient atmosphere. Enhancements of two and four orders of magnitude, reaching 4.0 × 10{sup −11} S/cm with a dopant concentration of only 2 mol% Cu(hfac){sub 2} and 1.5 × 10{sup −9} S/cm with 5 mol% Cu(tfac){sub 2} in 2,2′,7,7′-tetra(N,N-ditolyl)amino-9,9-spiro-bifluorene (spiro-TTB), respectively, were achieved. Red light emitting diodes were fabricated with reduced driving voltages and enhanced current and power efficiencies (8.6 lm/W with Cu(hfac){sub 2} and 5.6 lm/W with Cu(tfac){sub 2}) compared to the OLED with undoped spiro-TTB (3.9 lm/W). The OLED with Cu(hfac){sub 2} doped spiro-TTB showed an over 8 times improved LT{sub 50} lifetime of 70 h at a starting luminance of 5000 cd/m{sup 2}. The LT{sub 50} lifetime of the reference OLED with PEDOT:PSS was only 8 h. Both non-optimized OLEDs were operated at similar driving voltage and power efficiency.

  13. Copper-Sulfur Complexes Supported by N-Donor Ligands: Towards Models of the Cu(Z) Site in Nitrous Oxide Reductase.

    Science.gov (United States)

    York, John T; Bar-Nahum, Itsik; Tolman, William B

    2008-03-03

    The distinctive structure of the [(his)(7)Cu(4)(μ-S)](n+) cluster in the "Cu(Z)" active site of nitrous oxide reductase and the intriguing mechanistic hypotheses for its catalytic reactivity provide inspiration for synthetic model studies aimed at characterizing relevant copper-sulfur compounds and obtaining fundamental insights into structure and bonding. In this brief review, we summarize such studies that have focused on the synthesis and characterization of a range of copper-sulfur complexes supported by N-donor ligands. Compounds with variable nuclearities and sulfur redox levels have been isolated, with the nature of the species obtained being dependent on the supporting ligand, sulfur source, and the reaction conditions. Spectroscopic data and theoretical calculations, often performed with a view toward drawing comparisons to oxygen analogs, have provided insight into the nature of the copper-sulfur bonding interactions in the complexes.

  14. Copper(II) complexes of methimazole, an anti Grave's disease drug. Synthesis, characterization and its potential biological behavior as alkaline phosphatase inhibitor.

    Science.gov (United States)

    Urquiza, Nora M; Manca, Silvia G; Moyano, María A; Dellmans, Raquel Arrieta; Lezama, Luis; Rojo, Teófilo; Naso, Luciana G; Williams, Patricia A M; Ferrer, Evelina G

    2010-04-01

    Methimazole (MeimzH) is an anti-thyroid drug and the first choice for patients with Grave's disease. Two new copper(II) complexes of this drug: [Cu(MeimzH)(2)(NO(3))(2)]*0.5H(2)O and [Cu(MeimzH)(2)(H(2)O)(2)](NO(3))(2)*H(2)O were synthesized and characterized by elemental analysis, dissolution behavior, thermogravimetric analysis and UV-vis, diffuse reflectance, FTIR and EPR spectroscopies. As it is known that copper(II) cation can act as an inhibitor of alkaline phosphatase (ALP), the inhibitory effect of methimazole and its copper(II) complexes on ALP activity has also been investigated.

  15. A [2 x 2] nickel(ii) grid and a copper(ii) square result from differing binding modes of a pyrazine-based diamide ligand.

    Science.gov (United States)

    Klingele, Julia; Boas, John F; Pilbrow, John R; Moubaraki, Boujemaa; Murray, Keith S; Berry, Kevin J; Hunter, Keith A; Jameson, Geoffrey B; Boyd, Peter D W; Brooker, Sally

    2007-02-14

    The potentially bis-terdentate diamide ligand N,N'-bis[2-(2-pyridyl)ethyl]pyrazine-2,3-dicarboxamide (H(2)L(Et)) was structurally characterised. Potentiometric titrations revealed rather low pK(a) values for the deprotonation of the first amide group of H(2)L(Et) (14.2) and N,N'-bis(2-pyridylmethyl)pyrazine-2,3-dicarboxamide (H(2)L(Me), 13.1). Two tetranuclear copper(ii) square complexes of H(2)L(Et) with a paddle-wheel appearance, in which each ligand strand acts as a linear N(3)-NO hybrid terdentate-bidentate chelate, have been isolated and structurally characterised. Complex [Cu(II)(4)(H(2)L(Et))(2)(HL(Et))(2)](BF(4))(6).3MeCN.0.5H(2)O (.3MeCN.0.5H(2)O), with two nondeprotonated zwitterionic ligand strands and two monodeprotonated ligand strands, is formed in the 1 : 1 reaction of H(2)L(Et) and Cu(BF(4))(2).4H(2)O. It has a polymeric chain structure of tetranuclear subunits connected by N-H[dot dot dot]N hydrogen bonds. The same reaction carried out with one equivalent of base gives the related compound [Cu(II)(4)(HL(Et))(4)](BF(4))(4) (), with all four ligand strands monodeprotonated. It consists of isolated tetranuclear units. In both .3MeCN.0.5 H(2)O and the copper(ii) ions are in five-coordinate N(4)O environments but the degree of trigonality (tau) differs [.3MeCN.0.5H(2)O 0.14 complex, [Ni(II)(4)(HL(Et))(4)](BF(4)).10H(2)O (.10H(2)O), is formed. The structure determination showed that the nickel(ii) ions have N(6) distorted octahedral coordination spheres and all four ligand strands are monodeprotonated and act as N(3)-N(3) bis-terdentate chelates. Magnetic susceptibility data show that the complexes .4H(2)O, and .10H(2)O exhibit very weak antiferromagnetic spin coupling. The energies and multiplicities of the spin states of .4H(2)O and were determined from the temperature dependence of the magnetic susceptibility and indicate that a singlet state is lowest and the quintet state highest. This is consistent with the X-band EPR spectra of polycrystalline

  16. A versatile in vivo footprinting technique using 1,10-phenanthroline–copper complex to study important cellular processes

    Science.gov (United States)

    Basak, Shashwati; Nagaraja, V.

    2001-01-01

    A number of reagents have been used to define the sequence-specific protein–DNA contacts by footprinting analysis. We report a new in vivo technique using the complex of 1,10-phenanthroline and copper [(OP2)Cu] as a probe to study various intracellular DNA–protein interactions in whole cells. The versatility of the protocol is demonstrated by applying the technique to address various processes. The protocol is applied to (i) detect structural alterations in DNA as a result of single base substitution, (ii) footprint site-specific DNA-binding proteins, (iii) analyze promoter occupancy by RNA polymerase and (iv) analyze molecular interactions during transcription initiation. The results demonstrate that in vivo (OP)2Cu probing is a useful tool in studying important cellular processes involving DNA–protein interactions and has potential applications in post-genomic research. PMID:11691942

  17. The interaction of taurine-salicylaldehyde Schiff base copper(II) complex with DNA and the determination of DNA using the complex as a fluorescence probe.

    Science.gov (United States)

    Zhang, Xiaoyan; Wang, Yong; Zhang, Qianru; Yang, Zhousheng

    2010-09-15

    The interaction of taurine-salicylaldehyde Schiff base copper(II) (Cu(TSSB)2(2+)) complex with DNA was explored by using UV-vis, fluorescence spectrophotometry, and voltammetry. In pH 7.4 Tris-HCl buffer solution, the binding constant of the Cu(TSSB)2(2+) complex interaction with DNA was 3.49 x 10(4) L mol(-1). Moreover, due to the fluorescence enhancing of Cu(TSSB)2(2+) complex in the presence of DNA, a method for determination of DNA with Cu(TSSB)2(2+) complex as a fluorescence probe was developed. The fluorescence spectra indicated that the maximum excitation and emission wavelength were 389 nm and 512 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range of 0.03-9.03 microg mL(-1) for calf thymus DNA (CT-DNA), 0.10-36 microg mL(-1) for yeast DNA and 0.01-10.01 microg mL(-1) for salmon DNA (SM-DNA), respectively. The corresponding detection limits are 7 ng mL(-1) for CT-DNA, 3 ng mL(-1) for yeast DNA and 3 ng mL(-1) for SM-DNA. Using this method, DNA in synthetic samples was determined with satisfactory results.

  18. Copper(II) Complexes with Saccharinate and Glutamine as Antitumor Agents: Cytoand Genotoxicity in Human Osteosarcoma Cells.

    Science.gov (United States)

    Cadavid-Vargas, Juan F; Leon, Ignacio E; Etcheverry, Susana B; Santi, Eduardo; Torre, Maria H; Di Virgilio, Ana L

    2017-01-01

    Copper has shown to be useful in disorders with an inflammation origin such as cancer [1-3]. It has previously shown that Casiopeínas® interact with DNA and promote the disruption by a mechanism related to the increase in the level of free radicals [4-6] which confers antineoplastic potential. Objetive: The aim of the present work was to study the antitumor effects of a series of Cu(II) complexes with saccharinate (sac) and glutamate (gln): [Cu(sac)2(H2O)4].2H2O (Cu-sac), [Cu(gln)2] (Cu-gln) and Na2[Cu(sac)2 (gln)2].H2O (Cu-sac-gln). We have investigated the action of these compounds on cell viability on human osteosarcoma cells MG-63. In particular, we pay special attention to the cyto and genotoxicity actions of these complexes and to the association to oxidative stress. The three complexes: Cu-sac, Cu-gln and Cu-sac-gln caused a decline in cell viability. The half-maximal inhibitory concentration in MG-63 cells for Cu-sac-gln is 170 µM, showing the strongest antiproliferative effect. Moreover, only Cu-sac-gln caused a decrease of the mitochondrial activity from 100 µM. Our results indicate that the copper(II) complexes studied here produce DNA damage and suggest that the rise of reactive oxygen species (ROS) is the central mechanism action. Genotoxicity studied by the Cytokinesis-block micronucleus (MN) assay and the Single cell gel electrophoresis (comet assay) could be observed in MG-63 cells treated with Cu-sac-gln from 100 and 50 µM, respectively. Cu-sac and Cu-gln also induced DNA damage; however their effect was definitively weaker. The generation of reactive oxygen species increased from 50 μM of Cu-sac-gln and Cu-sac and only from 250 µM of Cugln, as well as a reduction of the GSH/GSSG ratio from 50 µM. When cells were treated with several concentrations of the complexes in addition to a combination of 50 μM of vitamin C plus 50 µM of vitamin E, a total recovery in cell survival was obtained for Cu-gln in the whole range of tested

  19. Copper(II and lead(II complexation by humic acid and humic-like ligands

    Directory of Open Access Journals (Sweden)

    IVANA KOSTIĆ

    2011-09-01

    Full Text Available The stability of metal–humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II and Pb(II with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25 °C and at an ionic strength of 0.01 mol dm-3 (NaCl using the Schubert ion-exchange method and its modified form. The stability constants were calculated from the experimental data by the Schubert method for complexes with benzoic and humic acid. A modified Schubert method was used for the determination of the stability constants of the complexes with salicylic acid. It was found that Cu(II and Pb(II form mononuclear complexes with benzoic and humic acid while with salicylic acid both metals form polynuclear complexes. The results indicate that Pb(II has a higher binding ability than Cu(II to all the investigated ligands. The Cu(II–salicylate and Pb(II–salicylate complexes showed noticeable higher stability constants compared with their complexes with humic acid, while the stabilities of the complexes with benzoic acid differed less. Salicylic and benzoic acids as humic-like ligands can be used for setting the range of stability constants of humic complexes with Cu(II and Pb(II.

  20. Copper(II) complexes of mono-anionic glutamate: anionic influence in the variations of molecular and supramolecular structures.

    Science.gov (United States)

    Biswas, Chaitali; Drew, Michael G B; Estrader, Marta; Ghosh, Ashutosh

    2009-07-07

    Three new polynuclear copper(II) complexes of singly deprotonated L-glutamic acid (L-glu), {[Cu(bipy)2][Cu(bipy)(L-glu)H2O]2(BF4)4 x (H2O)3}n (1), {[Cu(bipy)(L-glu)H2O][Cu(bipy)(L-glu)(ClO4)](ClO4) x (H2O)2}n (2) and [Cu(phen)(L-glu)H2O]2(NO3)2 x (H2O)4 (3) (bipy = 2,2-bipyridine, phen = 1,10-phenanthroline), were synthesized in acidic pH (ca. 2.5) and characterized structurally. In all the complexes, L-glutamic acid acts as a bidentate chelating ligand, leaving the protonated carboxylic acid free. Both in 1 and 2, two different types of species [Cu(bipy)2](BF4)2 and [Cu(bipy)(L-glu)H2O]BF4 for 1 and [Cu(bipy)(L-glu)H2O]ClO4 and [Cu(bipy)(L-glu)(ClO4)] for 2 coexist in the solid state. In complex 1, the [Cu(bipy)(L-glu)H2O]+ units are joined together by syn-anti carboxylate bridges to form an enantiopure (M) helical chain and the [Cu(bipy)2]2+ presents a very rare example of the four-coordinate distorted tetrahedral geometry of Cu(II). In complex 2, the [Cu(bipy)(L-glu)(ClO4)] units are joined together by weakly coordinating perchlorate ions to form a 1D polymeric chain while the [Cu(bipy)(L-glu)H2O]+ units remain as mononuclear species. The different coordinating ability of the two counter anions along with their involvement in the H-bonding network seems likely to be responsible for the difference in the final polymeric structures in the two compounds. Variable-temperature (2-300 K) magnetic susceptibility measurements show negligible coupling for both the complexes. The structure of 3 consists of two independent monomeric [Cu(phen)(L-glu)H2O]+ cations, two nitrate anions and four water molecules. The copper atom occupies a five-coordinate square pyramidal environment with a water molecule in the axial position.

  1. Novel aminonaphthoquinone mannich bases derived from lawsone and their copper(II) complexes: synthesis, characterization and antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Amanda P.; Barbosa, Claudia C.; Greco, Sandro J.; Vargas, Maria D. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Quimica; Visentin, Lorenzo C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica; Pinheiro, Carlos B. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Mangrich, Antonio S. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Centro Politecnico. Dept. de Quimica; Barbosa, Jussara P.; Costa, Gisela L. da [Instituto Oswaldo Cruz, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    A series of novel Mannich bases (HL1-HL13) derived from 2-hydroxy-1,4-naphthoquinone (lawsone), substituted benzaldehydes [C{sub 6}H{sub 2}R{sup 1}R{sup 2}R{sup 3}C(O)H] and various primary amines (NH{sub 2}R{sup 4}, R{sup 4} = n-butyl, benzyl, allyl, 2-furfuryl), and their Cu{sup 2+} complexes, [Cu(L1){sub 2}]-[Cu(L13){sub 2}], have been synthesized and fully characterized by analytical and spectroscopic methods. The structures of complexes 1 (R{sup 1} R{sup 2} = R{sup 3} = H; R{sup 4} = Bu), 2 (R{sup 1} = R{sup 3} = H; R{sup 2} = NO{sub 2}; R{sup 4}= Bu) and 7 (R{sup 1} OH; R{sup 2} = R{sup 3} = H; R{sup 4}= Bu) were determined by single crystal X-ray diffraction studies. All complexes crystallize in centrosymmetric space groups, with a copper atom in the inversion centre. Two L. coordinate through the naphthalen-2-olate oxygen and secondary amine-N atoms, forming six membered chelate rings around the copper atom in a trans-N{sub 2}O{sub 2} environment; spectroscopic data confirm that the other complexes exhibit similar molecular arrangement. The antimicrobial activity of all compounds has been tested on seven different strains of bacteria: Bacillus cereus, Bacillus subtilis, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. In general, Mannich bases were more active than complexes, HL11 (R{sup 1} = OH; R{sup 2} =H; R{sup 3} = Me; R{sup 4}= Bn) and HL13 (R{sup 1} = OH; R{sup 2} = H; R{sup 3} = Br; R{sup 4}= Bn) being the most potent inhibitors. The MIC for the most active compound HL11 against S. Coli was 20 {mu}mol L{sup -1} (8 {mu}g mL{sup -1}), better than Chloramphenicol (90 {mu}mol L{sup -1}) and well below most values reported for other naphthoquinones. (author)

  2. Interaction of drug based copper(II) complexes with Herring Sperm DNA and their biological activities

    Science.gov (United States)

    Patel, Mohan N.; Patel, Chintan R.; Joshi, Hardik N.

    2012-11-01

    Square pyramidal Cu(II) complexes with NS donor ligand and ciprofloxacin have been synthesized and characterized using analytical and spectral techniques. The synthesized complexes have been tested for their antimicrobial activity using double dilution technique in terms of minimum inhibitory concentration (MIC) and colony forming unit (CFU). The DNA binding ability of the complexes with Sperm Herring DNA has been performed using absorption titration and viscosity measurement. The nuclease activity of complexes with plasmid DNA (pUC19) has been carried out using agarose gel electrophoresis technique. Synthesized complexes have been tested for their SOD mimic activity using NBT/NADH/PMS system. The cytotoxic properties of metal complexes have been evaluated using brine shrimp lethality bioassay.

  3. Synthesis, electronic and ESR spectral studies on copper(II) nitrate complexes with some acylhydrazines and hydrazones

    Science.gov (United States)

    Singh, Vinod P.

    2008-11-01

    This paper describes the preparation of [Cu(bh) 2(H 2O) 2](NO 3) 2], [Cu(ibh) 2(NO 3) 2], [Cu(ibh) 2(H 2O) 2](NO 3) 2 and [Cu(iinh) 2(NO 3) 2] (bh = benzoyl hydrazine (C 6H 5CONHNH 2); ibh = isonicotinoyl hydrazine (NC 5H 4CONHNH 2); ibh = isopropanone benzoyl hydrazone (C 6H 5CONHN=C(CH 3) 2; iinh = isopropanone isonicotinoyl hydrazone (NC 5H 4CONHN=C(CH 3) 2). These copper(II) complexes are characterized by elemental analyses, molar conductances, dehydration studies, ESR, IR and electronic spectral studies. The electronic and ESR spectra indicate that each complex exhibits a six-coordinate tetragonally distorted octahedral geometry in the solid state and in DMSO solution. The ESR spectra of most of the complexes are typically isotropic type at room temperature (300 K) in solid state as well as in DMSO solution. However, all the complexes exhibit invariably axial signals at 77 K in DMSO solution. The trend g|| > g⊥ > ge, observed in all the complexes suggests the presence of an unpaired electron in the d-y orbital of the Cu(II). The bh and inh ligands bond to Cu(II) through the >C dbnd O and sbnd NH 2 groups whereas, ibh and iinh bond through >C dbnd O and >C dbnd N sbnd groups. The IR spectra of bh and ibh complexes also show H sbnd O sbnd H stretching and bending modes of coordinated water.

  4. Structural and functional effects of benzimidazole/thioether-copper complexes with antitumor activity on cell membranes and molecular models.

    Science.gov (United States)

    Castillo, Ivan; Suwalsky, Mario; Gallardo, María José; Troncoso, Valentina; Sánchez-Eguía, Brenda N; Santiago-Osorio, Edelmiro; Aguiñiga, Itzen; González-Ugarte, Ana K

    2016-03-01

    Two cytotoxic copper(II) complexes with N-H and N-methylated benzimidazole-derived ligands (Cu-L(2) and Cu-L(2Me)) were synthesized and made to interact with human erythrocytes and molecular models of their plasmatic membranes. The latter consisted in lipid bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), lipids of the types present in the outer and inner monolayers of the human erythrocyte membrane, respectively. Initial assessment of the interaction of the complexes with DMPC and DMPE consisted of X-ray diffraction studies, which showed preferential interactions with the former. Scanning electron microscopy (SEM) of erythrocytes incubated with solutions of the Cu(II) complexes evidenced deformation of the cells to stomatocytes and knizocytes by Cu-L(2) and Cu-L(2Me) due to interactions with the inner and outer leaflets of the cell membranes, respectively. This was further confirmed by real-time observation of the dose-dependent effects of the complexes on live erythrocytes by defocusing microscopy (DM). The combined observations, including the increased antiproliferative activity of the N-methylated complex Cu-L(2Me) over that of Cu-L(2) is rationalized based on the higher lipophilicity of the former. This property would facilitate passive diffusion of Cu-L(2Me) through the cell membrane, particularly in the initial stages when the DMPC-rich outer leaflet is involved. In contrast, the benzimidazole N-H groups of Cu-L(2) may participate in hydrogen bonding with DMPE polar groups; this result is consistent with the formation of stomatocyte induced by the latter complex. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. An artificial enzyme-based assay: DNA detection using a peroxidase-like copper-creatinine complex.

    Science.gov (United States)

    Singh, Amardeep; Patra, Srikanta; Lee, Jeong-Ah; Park, Kang Hyun; Yang, Haesik

    2011-08-15

    We report an artificial enzyme-based DNA assay using a peroxidase-like copper (Cu)-creatinine complex as a catalyst for 3,3',5,5'-tetramethylbenzidine (TMB) oxidation. The assay employs double signal amplification and a homogeneous catalytic reaction: (i) fast catalytic growth of Cu on a gold (Au) nanoparticle (NP) label forms a thick Cu layer (first amplification); (ii) dissolution of the Cu layer generates many Cu-creatinine complexes per NP (generation of homogeneous catalysts); (iii) peroxidase-like Cu-creatinine complexes rapidly convert TMB into a colored product (second amplification). To investigate the effect of ligand on the catalytic activities of Cu complexes, the kinetics of catalytic TMB oxidation is tested with and without using imidazole ring-containing ligands (creatinine, imidazole, and poly(l-histidine)). Both fast oxidation of TMB and slow further oxidation of the colored product are required for high signal-to-background ratios. Cu-creatinine complex allows relatively fast oxidation and slow further oxidation. Fast seed-mediated Cu growth on Au NP and slow Cu autonucleation (i.e., slow formation of Cu NP in the absence of Au NP) are also required for high signal-to-background ratios. In tris-EDTA (tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetic acid) buffer (pH 7.7) containing high concentrations of Cu(2+) (90 mM), ascorbic acid (50mM), and Mg(2+) (200 mM), Cu growth on Au NP is very fast and autonucleation is significantly suppressed. Fast catalytic oxidation by Cu-creatinine complex along with fast Cu growth on Au NP allows a detection limit of 0.1 pM for DNA in a simple microplate format. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Ethambutol analysis by copper complexation in pharmaceutical formulations: spectrophotometry and crystal structure

    OpenAIRE

    Faria,Adriana F.; Marcellos,Luiza F; Vasconcelos,Juliana P; Marcus V. N. de Souza; S. Júnior,Antônio L; Carmo,Weberton R. do; Diniz, Renata; Oliveira,Marcone A. L. de

    2011-01-01

    An alternative method for ethambutol (ETB) determination by UV spectrophotometry in pharmaceutical formulations using ETB complexation with Cu(II) was optimized employing a 3² full experimental design having Cu(II) and aqueous acetic acid/sodium acetate buffer at pH 4.6 as variables. The predominant complex stoichiometry in aqueous buffer solution at this pH and formation constant were obtained by using Job's method and Scatchard diagram, respectively. The complex crystalline structure of mon...

  7. Mono-, di- and tetranuclear rhodium(I) complexes of morpholine and ...

    Indian Academy of Sciences (India)

    10. Sheldrick G W SADABS Versions 2.05 and 2007/4 2002. 2007 University of Göttingen Germany. 11. (a) Sheldrick G W TWINABS 2002 2007 University of. Göttingen Germany; (b) SHELXTL Version 6.10 2000. Bruker–AXS Madison WI. 12. Suarez A, Mendez-Rojas M A and Pizanno A 2002. Organometallics 21 4611.

  8. An X-ray photoelectron spectroscopy and quantum chemical study of copper(II) β-diketonates and Cu(HFA){sub 2} complexes with imidazoline ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kryuchkova, Natalya A., E-mail: knatali@ngs.ru [Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Lavrentyev Av., 3, RU-630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova Street, 2, RU-630090 Novosibirsk (Russian Federation); Stabnikov, Pavel A. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Lavrentyev Av., 3, RU-630090 Novosibirsk (Russian Federation); Kalinkin, Alexander V. [Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Lavrentyev Av., 5, RU-630090 Novosibirsk (Russian Federation); Fursova, Elena Yu. [International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya Street, 3a, RU-630090 Novosibirsk (Russian Federation)

    2016-10-15

    Highlights: • The charge and spin states of Cu(II) β-diketonates and Cu(hfa){sub 2}(imidazoline) are investigated by the XPS and DFT calculations. • The |2p{sup 5}3d{sup 9}> and | 2p{sup 5}3d{sup 10}L> electronic states are asigned to X-ray photoelectron spectra of copper. - Abstract: An X-ray photoelectron spectroscopy study of the charge and spin state of copper(II) β-diketonates and Cu(hfa){sub 2} (hfa–hexafluoroacetylacetonate) complexes with imidazoline ligands is performed with comparison to the data of quantum chemical calculations. It is shown that the structure of the spectra of copper is described by a superposition of the |2p{sup 5}3d{sup 9}> and | 2p{sup 5}3d{sup 10}L> electronic states determined by electron transfer processes between copper and L ligand atoms. It is found that during the coordination of imidazoline ligands to the Cu(hfa){sub 2} complex the spin density is redistributed through the chain of chemical bonds from the ligand nitroxyl group to the copper atom.

  9. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N⁴-methyl-3-thiosemicarbazone: crystal structure of a novel sulfur bridged copper(II) box-dimer.

    Science.gov (United States)

    Jayakumar, K; Sithambaresan, M; Aiswarya, N; Kurup, M R Prathapachandra

    2015-03-15

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ=0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g||>g⊥>2.0023 and the g values in frozen DMF are consistent with the d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

    Science.gov (United States)

    Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

    2015-03-01

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

  11. Complexes cobalt(II, zinc(II and copper(II with some newly synthesized benzimidazole derivatives and their antibacterial activity

    Directory of Open Access Journals (Sweden)

    S. O. PODUNAVAC-KUZMANOVIC

    1999-05-01

    Full Text Available The preparation and properties of some complexes of cobalt(II, zinc(II and copper(II with several newly synthesized benzimidazole derivatives (L are reported. The complexes, of the general formula [MCl2L2] (M=Co(II, Zn(II and [CuCl2L(H2O], have a tetrahedral structure. The complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility measurements, IR and absorption electronic spectra. The antibacterial activitiy of the benzimidazoles and their complexes was evaluated against Erwinia carotovora subsp. carotovora and Erwinia amylovora. The complexes were found to be more toxic than the ligands.

  12. Joint toxicity of tetracycline with copper(II) and cadmium(II) to Vibrio fischeri: effect of complexation reaction.

    Science.gov (United States)

    Tong, Fei; Zhao, Yanping; Gu, Xueyuan; Gu, Cheng; Lee, Charles C C

    2015-03-01

    Co-contamination of antibiotic and heavy metals commonly occurs in the environment. Tetracycline (TC), a common antibiotic, can behave as an efficient organic ligand to complex with cations. In this paper, the joint toxicity of TC with two commonly existing metals, copper(II) and cadmium(II), towards a luminescent bacteria, Vibrio fischeri, are investigated. Results showed that coexistence of TC and Cu(II) showed a significant antagonistic effect, while TC and Cd(II) showed a synergistic effect. The aqueous speciation of TC with two metal cations was calculated using a chemical equilibrium software Visual MINTEQ and results indicated that a strong complexation exist between TC and Cu(II), while much weaker interaction between TC and Cd(II). Traditional joint toxicity prediction model based on independent action failed to predict the combined toxicity of TC with metals. A new method based on speciation calculation was used to evaluate the joint toxicity of ligands and cations. It is assumed that the metal-ligand complexes are non-toxic to V. fischeri and the joint toxicity is determined by the sum of toxic unit of free metal-ions and free organic ligands. It explained the joint toxicity of the mixed systems reasonably well. Meanwhile, citric acid (CA) and fulvic acid (FA) were also introduced in this study to provide a benchmark comparison with TC. Results showed it is also valid for mixed systems of CA and FA with metals except for the Cd-CA mixture.

  13. Square pyramidal copper(II) complexes with forth generation fluoroquinolone and neutral bidentate ligand: structure, antibacterial, SOD mimic and DNA-interaction studies.

    Science.gov (United States)

    Patel, Mohan N; Parmar, Pradhuman A; Gandhi, Deepen S

    2010-02-01

    Coordination of neutral bidentate ligand to copper ion in combination with gatifloxacin have been focused in this article. The effect of complexation reflects antibacterial activity, DNA interaction and SOD mimic activity of individual greatly. The geometry at the central metal ion provides a site for binding of superoxide anion responsible for better SOD mimic behaviour. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. Investigating the Structure and Reactivity of Azolyl-Based Copper(I)–NHC Complexes: The Role of the Anionic Ligand

    KAUST Repository

    Trose, Michael

    2017-11-01

    A family of copper(I)–NHC azolyl complexes was synthesized and deployed in the hydrosilylation of dicyclo-hexylketone to probe the role of the anionic ligand on catalytic performance. The azolyl ligand is shown to have a crucial role in catalytic activity without the need for additives, and this at very low catalyst loading.

  15. The relation between salinity and copper complexing capacity of natural estuarine waters and the uptake of dissolved 64Cu by Macoma balthica

    NARCIS (Netherlands)

    Absil, M.C.P.; Gerringa, L.J.A.; Wolterbeek, H.T.

    1993-01-01

    The radiotracer 64Cu was used to assess the influence of natural organic ligands on the bioavailability of copper. Biological availability of the 64Cu-complexes was measured by accumulation in the bivalve Macoma balthica. The experiments were carried out in April as well as in February with water

  16. Copper-based metal coordination complexes with Voriconazole ligand: Syntheses, structures and antimicrobial properties

    Science.gov (United States)

    Zhao, Yan-Ming; Tang, Gui-Mei; Wang, Yong-Tao; Cui, Yue-Zhi; Ng, Seik Weng

    2018-03-01

    Three new chiral metal coordination complexes, namely, [Cu(FZ)2(CH3COO)2(H2O)]·2H2O (1), [Cu(FZ)2(NO3)2] (2), and [Cu2(FZ)2 (H2O)8](SO4)2·4H2O (3) [FZ = (2R,3S)-2-(2,4-difluorophenyl)-3-(5-fluoro-4-pyrimidiny)-1-(1H-1,2,4-triazol-1-yl)-2-butanol) (Voriconazole)] have been obtained by the reaction of Cu(II) salts and the free ligand FZ at room temperature. Complexes 1-3 were structurally characterized by X-ray single-crystal diffraction, IR, UV-vis, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complex 1 crystallizes in the chiral space group C2, which exhibits a mono-nuclear structure. Both complexes 2 and 3 display a one-dimensional (1D) tape structure, which crystallize in chiral space group P21212 and P212121, respectively. Among these complexes, there exist a variety of hydrogen bonds and stacking interactions, through which a three-dimensional supramolecular architecture will be generated. Compared with the standard (Voriconazole), these Cu-based complexes show the more potent inhibiting efficiency against the species of Candida and Aspergillus. Moreover, among these complexes, complex 1 shows the most excellent efficiency.

  17. Mixed-ligand copper (II) complexes of dipicolylamine and 1, 10 ...

    Indian Academy of Sciences (India)

    An intercalative mode of DNA interaction, which involves the insertion of dpq and to a lesser extent the phen ring of the complexes in between the DNA base pairs, is proposed. However, interestingly, the 5,6-dmp complex is involved in hydrophobic interaction of the 5,6-dmp ring in the grooves of DNA. The large ...

  18. Synthesis, crystal structure and spectroscopic and electrochemical properties of bridged trisbenzoato copper-zinc heterobinuclear complex of 2,2‧-bipyridine

    Science.gov (United States)

    Koch, Angira; Kumar, Arvind; Singh, Suryabhan; Borthakur, Rosmita; Basumatary, Debajani; Lal, Ram A.; Shangpung, Sankey

    2015-03-01

    The synthesis of the heterobinuclear copper-zinc complex [CuZn(bz)3(bpy)2]ClO4 (bz = benzoate) from benzoic acid and bipyridine is described. Single crystal X-ray diffraction studies of the heterobinuclear complex reveals the geometry of the benzoato bridged Cu(II)-Zn(II) centre. The copper or zinc atom is pentacoordinate, with two oxygen atoms from bridging benzoato groups and two nitrogen atoms from one bipyridine forming an approximate plane and a bridging oxygen atom from a monodentate benzoate group. The Cu-Zn distance is 3.345 Å. The complex is normal paramagnetic having μeff value equal to 1.75 BM, ruling out the possibility of Cu-Cu interaction in the structural unit. The ESR spectrum of the complex in CH3CN at RT exhibit an isotropic four line spectrum centred at g = 2.142 and hyperfine coupling constants Aav = 63 × 10-4 cm-1, characteristic of a mononuclear square-pyramidal copper(II) complexes. At LNT, the complex shows an isotropic spectrum with g|| = 2.254 and g⊥ = 2.071 and A|| = 160 × 10-4 cm-1. The Hamiltonian parameters are characteristic of distorted square pyramidal geometry. Cyclic voltammetric studies of the complex have indicated quasi-reversible behaviour in acetonitrile solution.

  19. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines

    Science.gov (United States)

    Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

    2014-12-01

    A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

  20. Copper (II) complex of 1,10-phenanthroline and L-tyrosine with DNA oxidative cleavage activity in the gallic acid.

    Science.gov (United States)

    Yang, Zhousheng; Wang, Yong; Yang, Geng

    2011-08-01

    Copper (II) complex of formulation [Cu-Phen-Tyr](H(2)O)](ClO(4)) (Phen = 1,10-phenanthroline, L: -Tyr = L: -tyrosine), has been prepared, and their induced DNA oxidative cleavage activity studied. The complex binds to DNA by intercalation, as deduced from the absorption and fluorescence spectral data. Scatchard plots constructed from the absorption titration data gave binding constant 2.44 × 10(4) M(-1) of base pairs. Extensive hypochromism, broadening, and red shifts in the absorption spectra were observed. Upon binding to DNA, the fluorescence from the DNA--ethidium bromide system was efficiently quenched by the copper (II) complex. Stern--Volmer quenching constant 0.61 × 10(3) M(-1) obtained from the linear quenching plots. [Cu-Phen-Tyr] complex efficiently cleave the supercoiled DNA to its nicked circular form with gallic acid as biological reductant at appropriate complex concentration. The gallic acid as reductant could observably improve copper (II) complex to DNA damage. The pseudo-Michaelis-Menten kinetic parameters (k(cat), K(M)) were calculated to be 1.32 h(-1) and 5.46 × 10(-5) M for [Cu-Phen-Tyr] complex. Mechanistic studies reveal the involvement of superoxide anions and hydroxyl radical (HO(·)) as the reactive species under an aerobic medium.

  1. Examination of the Impact of Copper(II) α-(N)-Heterocyclic Thiosemicarbazone Complexes on DNA Topoisomerase IIα.

    Science.gov (United States)

    Wilson, James T; Jiang, Xiaohua; McGill, Bradley C; Lisic, Edward C; Deweese, Joseph E

    2016-04-18

    Type II DNA topoisomerases resolve topological knots and tangles in DNA that result from routine cellular processes and are effective targets for anticancer therapeutics. To this end, thiosemicarbazones have been identified as having the ability to kill cancer cells from several cell lines. Literature evidence suggests that at least some thiosemicarbazones have an impact on topoisomerase II activity. However, the mechanism is not as clearly defined. Therefore, we set out to analyze the activity of four α-(N)-heterocyclic thiosemicarbazone compounds against topoisomerase IIα. The ligands, acetylpyridine-ethylthiosemicarbazone (APY-ETSC) and acetylpyrazine-methylthiosemicarbazone (APZ-MTSC), and their copper(II) [Cu(II)] complexes [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl] were examined for the ability to impact the catalytic cycle of human topoisomerase IIα. Both [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl] were more effective at inhibiting DNA relaxation compared with the ligands alone. Further, both [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl] increased double-stranded DNA cleavage levels without inhibiting topoisomerase IIα-mediated DNA ligation. The Cu(II) complexes inactivate enzyme activity over time suggesting a critical interaction with the enzyme. Additionally, we found that the Cu(II)-thiosemicarbazone complexes do not significantly impact DNA cleavage by the catalytic core of the enzyme. This evidence is supported by the fact that both [Cu(APY-ETSC)Cl] and [Cu(APZ-MTSC)Cl], and to a lesser extent the ligands, inhibit topoisomerase IIα-mediated ATP hydrolysis. Based upon kinetic analysis, the Cu(II) complexes appear to be noncompetitive inhibitors of the ATPase domain of topoisomerase IIα. Taken together, our results provide evidence that Cu(II) complexes of α-(N)-heterocyclic thiosemicarbazones catalytically inhibit the enzyme through the ATPase domain but also promote double-stranded DNA cleavage by the enzyme.

  2. Copper (II and 2,2'-bipyridine complexation improves chemopreventive effects of naringenin against breast tumor cells.

    Directory of Open Access Journals (Sweden)

    Júlio César Conceição Filho

    Full Text Available Cancer is the second leading cause of death worldwide and there is epidemiological evidence that demonstrates this tendency is emerging. Naringenin (NGEN is a trihydroxyflavanone that shows various biological effects such as antioxidant, anticancer, anti-inflammatory, and antiviral activities. It belongs to flavanone class, which represents flavonoids with a C6-C3-C6 skeleton. Flavonoids do not exhibit sufficient activity to be used for chemotherapy, however they can be chemically modified by complexation with metals such as copper (Cu (II for instance, in order to be applied for adjuvant therapy. This study investigated the effects of Cu(II and 2,2'-bipyridine complexation with naringenin on MDA-MB-231 cells. We demonstrated that naringenin complexed with Cu(II and 2,2'-bipyridine (NGENCuB was more efficient inhibiting colony formation, proliferation and migration of MDA-MB-231 tumor cells, than naringenin (NGEN itself. Furthermore, we verified that NGENCuB was more effective than NGEN inhibiting pro-MMP9 activity by zymography assays. Finally, through flow cytometry, we showed that NGENCuB is more efficient than NGEN inducing apoptosis in MDA-MB-231 cells. These results were confirmed by gene expression analysis in real time PCR. We observed that NGENCuB upregulated the expression of pro-apoptotic gene caspase-9, but did not change the expression of caspase-8 or anti-apoptotic gene Bcl-2. There are only few works investigating the effects of Cu(II complexation with naringenin on tumor cells. To the best of our knowledge, this is the first work describing the effects of Cu(II complexation of a flavonoid on MDA-MB-231 breast tumor cells.

  3. Anti-thyroid and antifungal activities, BSA interaction and acid phosphatase inhibition of methimazole copper(II) complexes.

    Science.gov (United States)

    Urquiza, Nora M; Islas, María S; Ariza, Santiago T; Jori, Nadir; Martínez Medina, Juan J; Lavecchia, Martín J; López Tévez, Leonor L; Lezama, Luis; Rojo, Teófilo; Williams, Patricia A M; Ferrer, Evelina G

    2015-03-05

    It has been reported that various metal coordination compounds have improved some biological properties. A high activity of acid phosphatase (AcP) is associated to several diseases (osteoporosis, Alzheimer's, prostate cancer, among others) and makes it a target for the development of new potential inhibitors. Anti-thyroid agents have disadvantageous side effects and the scarcity of medicines in this area motivated many researchers to synthesize new ones. Several copper(II) complexes have shown antifungal activities. In this work we presented for a first time the inhibition of AcP and the anti-thyroid activity produced by methimazole-Cu(II) complexes. Cu-Met ([Cu(MeimzH)2(H2O)2](NO3)2·H2O) produces a weak inhibition action while Cu-Met-phen ([Cu(MeimzH)2(phen)(H2O)2]Cl2) shows a strong inhibition effect (IC50 = 300 μM) being more effective than the reported behavior of vanadium complexes. Cu-Met-phen also presented a fairly good anti-thyroid activity with a formation constant value, Kc=1.02 × 10(10)M(-1) being 10(6) times more active than methimazole (Kc = 4.16 × 10(4)M(-1)) in opposition to Cu-Met which presented activity (Kc=9.54 × 10(3)M(-1)) but in a lesser extent than that of the free ligand. None of the complexes show antifungal activity except Cu-phen (MIC = 11.71 μgmL(-1) on Candidaalbicans) which was tested for comparison. Besides, albumin interaction experiments denoted high affinity toward the complexes and the calculated binding constants indicate reversible binding to the protein. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Gas-phase copper and silver complexes with phosphorothioate and phosphorodithioate pesticides investigated using electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mustapha, Adetayo M; Pasilis, Sofie P

    2015-01-01

    Efforts to improve agricultural productivity have led to a growing dependency on organophosphorus pesticides. Phosphorothioate and phosphorodithioate pesticides are organophosphorus pesticide subclasses with widespread application for the control of insects feeding on vegetables and fruits. However, even low doses of these pesticides can cause neurological problems in humans; thus, their determination and monitoring in agricultural foodstuffs is important for human health. Phosphorothioate and phosphorodithioate pesticides may be poorly ionized during electrospray, adversely affecting limits of detection. These pesticides can form complexes with Cu(2+) and Ag(+) , however, potentially improving ionization. In the present work, we used electrospray ionization/mass spectrometry (ESI/MS) to study fenitrothion, parathion, diazinon, and malathion coordination complexes with silver and copper ions. Stable 1 : 1 and 1 : 2 metal/pesticide complexes were detected. Mass spectra acquired from pesticide solutions containing Ag(+) or Cu(2+) showed a significant increase in signal-to-background ratio over those acquired from solutions containing only the pesticides, with Ag(+) improving detection more effectively than Cu(2+). Addition of Ag(+) to a pesticide solution improved the limit of detection by ten times. The relative affinity of each pesticide for Ag(+) was related to complex stability, following the order diazinon > malathion > fenitrothion > parathion. The formation of Ag(+)-pesticide complexes can significantly improve the detection of phosphorothioate and phosphorodithioate pesticides using ESI/MS. The technique could potentially be used in reactive desorption electrospray ionization/mass spectrometry to detect phosphorothioate and phosphorodithioate pesticides on fruit and vegetable skins. Copyright © 2015 John Wiley & Sons, Ltd.

  5. New copper(II) thiohydantoin complexes: Synthesis, characterization, and assessment of their interaction with bovine serum albumin and DNA.

    Science.gov (United States)

    Tishchenko, Ksenia; Beloglazkina, Elena; Proskurnin, Mikhail; Malinnikov, Vladislav; Guk, Dmitriy; Muratova, Marina; Krasnovskaya, Olga; Udina, Anna; Skvortsov, Dmitry; Shafikov, Radik R; Ivanenkov, Yan; Aladinskiy, Vladimir; Sorokin, Ivan; Gromov, Oleg; Majouga, Alexander; Zyk, Nikolay

    2017-10-01

    New copper(II) complexes of 2-alkylthio-5-arylmethylene-4H-imidazolin-4-ones: (5Z)-2-(methylsulfanyl)-3-(prop-2-en-1-yl)-5-(pyridin-2-ylmethylidene)-3,5-dihydro-4H-imidazol-4-one) (1a), (5Z,5'Z)-2,2'-(ethan-1,2-diyldisulfanyldiyl)bis(5-(2-pyridilmethylen)-3-allyl-3,5-dihydo-4Н-imidazole-4-one) (2a) and (5Z,5'Z)-3,3'-hexan-1,6-diylbis[5-(2-pyridilmethylen)-2-methylthiotetrahydro-4Н-imidazole-4-one)] (3a) were synthesized as possible anticancer drugs. Their structures were characterized by 1 H NMR spectroscopy, elemental analysis, and X-ray crystallography. The composition of the complexes were found for 1a (Cu:L=1:1), 2a (Cu:L=2:1), and 3a (Cu:L=2:1). The chelation constants were found by competitive complexation with ethylenediamine tetraacetate: 1a (6.7±0.6)×10 15 M -1 , 2a=(4.9±0.4)×10 19 M -2 , and 3a (5.7±0.5)×10 19 M -2 . Supramolecular binding with calf thymus DNA by competitive ethidium bromide quenching was made for complex 2a as the most promising anticancer model, the Stern-Volmer constants were found to be K SV =(8.0±0.4)×10 6 M -1 , K q =(6.5±0.4)×10 5 M -1 . The binding of the complex 2a to BSA was made by the Scatchard method, the value of the constant is K b =(1.9±0.2)×10 6 M -1 . Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Two novel copper complexes of 2,2'-bipyridine: evaluation of the DNA binding and cytotoxic activity.

    Science.gov (United States)

    Fei, Bao-Li; Li, Wen; Xu, Wu-Shuang; Li, Yang-Guang; Long, Jian-Ying; Liu, Qing-Bo; Shao, Kui-Zhan; Su, Zhong-Min; Sun, Wei-Yin

    2013-08-05

    Two novel copper-2,2'-bipyridine complexes [Cu(SAL)(2,2'-bipy)ClO4]2 (1) and [Cu(μ2-O)(2,2'-bipy)NO3]2 (2) (HSAL=salicylaldehyde) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis and IR spectra. The interactions of the complexes with salmon sperm DNA were investigated by viscosity analysis, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=3.00×10(5)M(-1) (1), 3.49×10(5)M(-1)(2)), emission spectral ((Ksv) 3.33×10(4)M(-1) (1), 3.40×10(4)M(-1) (2)), and viscosity measurements reveal that 1 and 2 interact with DNA through intercalation. In fluorimetric studies, the enthalpy (ΔH>0) and entropy (ΔS>0) changes of the reactions between the Cu (II) complexes with DNA demonstrate hydrophobic interactions. In addition, CD study indicates the Cu (II) complexes cause a more B-like to a more A-like conformational change upon binding DNA. All the experimental results show that the interaction mode of the two complexes was greatly affected by the coordination environments of Cu (II) centers. Their in vitro cytotoxicity towards five selected tumor cell lines HepG-2, HeLa, NCI-H460, MCF-7 and HL-60 has been evaluated by MTT method, and 2 exhibits higher growth inhibition of the selected cell lines at concentration of 50 μM, this result is identical with their DNA binding ability order. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. EPR study of complex formation between copper (II) ions and sympathomimetic amines in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Preoteasa, E.A. [Inst. of Atomic Physics, IFIN, Bucharest (Romania); Duliu, O.G.; Grecu, V.V. [Bucharest, Univ. (Romania). Dept. of Atomic and Nuclear Physics

    1997-07-01

    The complex formation between sympathomimetic amines (SA): adrenaline (AD), noradrenaline (NA), dopamine (DA), ephedrine (ED) and p-tyramine (pTA), and Cu(II) ion in aqueous solution has been studied by X-band EPR at room temperature. Excepting pTA, all investigated SA yielded two types of complexes in different pH domains. All complexes consistent with a ligand fields having a distorted octahedral symmetry, i.e., hexacoordination of Cu(II). The covalence coefficient calculated from the isotropic g and A values has shown strong ionic sigma-type ligand bonds. A structural model with the Cu(II) ion bound by four catecholic O(hydroxy) atoms for the low pH complexes of AD, NA and DA is proposed. For the high pH complexes of the former compounds as well as for both Ed complexes, the authors suppose Cu(II) bound by two N (amino) and two O (hydroxy) atoms. The spectra are consistent to water binding on the longitudinal octahedron axis in all compounds excepting the high pH complex of Ed, where OH2- ions are bound. Possible implications for the SA-cell receptors interactions are discussed.

  8. Binding of copper(II) polypyridyl complexes to DNA and consequences for DNA-based asymmetric catalysis.

    Science.gov (United States)

    Draksharapu, Apparao; Boersma, Arnold J; Leising, Miriam; Meetsma, Auke; Browne, Wesley R; Roelfes, Gerard

    2015-02-28

    The interaction between salmon testes DNA (st-DNA) and a series of Cu(II) polypyridyl complexes, i.e. [Cu(dmbpy)(NO3)2] (1) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine), [Cu(bpy)(NO3)2] (2) (bpy = 2,2'-bipyridine), [Cu(phen)(NO3)2] (3) (phen = phenanthroline), [Cu(terpy)(NO3)2]·H2O (4) (terpy = 2,2':6',2″-terpyridine), [Cu(dpq)(NO3)2] (5) (dpq = dipyrido-[3,2-d:2',3'-f]-quinoxaline) and [Cu(dppz)(NO3)2] (6) (dppz = dipyrido[3,2-a:2',3'-c]phenazine) was studied by UV/Vis absorption, Circular Dichroism, Linear Dichroism, EPR, Raman and (UV and vis) resonance Raman spectroscopies and viscometry. These complexes catalyse enantioselective C-C bond forming reactions in water with DNA as the source of chirality. Complex 1 crystallizes as an inorganic polymer with nitrate ligands bridging the copper ions, which adopt essentially a distorted square pyramidal structure with a fifth bridging nitrate ligand at the axial position. Raman spectroscopy indicates that in solution the nitrate ligands in 1, 2, 3 and 4 are displaced by solvent (H2O). For complex 1, multiple supramolecular species are observed in the presence of st-DNA in contrast to the other complexes, which appear to interact relatively uniformly as a single species predominantly, when st-DNA is present. Overall the data suggest that complexes 1 and 2 engage primarily through groove binding with st-DNA while 5 and 6 undergo intercalation. For complexes 3 and 4 the data indicates that both groove binding and intercalation takes place, albeit primarily intercalation. Although it is tempting to conclude that the groove binders give highest ee and rate acceleration, it is proposed that the flexibility and dynamics in binding of Cu(II) complexes to DNA are key parameters that determine the outcome of the reaction. These findings provide insight into the complex supramolecular structure of these DNA-based catalysts.

  9. Zeolite-Encapsulated Copper(II) Amino Acid Complexes: Synthesis, Spectroscopy, and Catalysis

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Verberckmoes, A.A.; Fu, L.; Schoonheydt, R.A.

    1995-01-01

    The spectroscopic properties and catalytic behavior of Cu(AA)n m+ complexes (AA ) amino acid (glycine, lysine, histidine, alanine, serine, proline, tyrosine, phenylalanine, glutamine, glutamic acid, cysteine, tryptophan, leucine, and arginine)) in faujasite-type zeolites have been investigated.

  10. Nuclease Activity via Self-Activation and Anticancer Activity of Mononuclear Copper(II) Complex: Novel Role of Tertiary Butyl Group in the Ligand Frame

    OpenAIRE

    Ghosh, Kaushik; Kumar, Pramod; Mohan, Varun; Singh, Udai P.; Kasiri, Sahba; Mandal, Subhrangsu S.

    2012-01-01

    Copper complex [Cu(tBuPhimp)(Cl)] (1) derived from tridentate ligand tBuPhimpH having N2O donors was synthesized and molecular structure was determined. Phenoxyl radical complex was generated in solution at room temperature using Ce(IV) salt. Nuclease activity and anticancer activity of 1 was investigated. Roles of tert-butyl group and singlet oxygen in DNA cleavage activity were also discussed.

  11. Copper(II) complexes with naringenin and hesperetin : cytotoxic activity against A 549 human lung adenocarcinoma cells and investigation on the mode of action

    NARCIS (Netherlands)

    Tamayo, Lenka V.; Gouvea, Ligiane R.; Sousa, Anna C.; Albuquerque, Ronniel M.; Teixeira, Sarah Fernandes; de Azevedo, Ricardo Alexandre; Louro, Sonia R. W.; Ferreira, Adilson Kleber; Beraldo, Heloisa

    Copper(II) complexes [Cu(H (2) O) (2) (L1)(phen)](ClO (4) ) (1) and [Cu(H (2) O)(L2)(phen)](ClO (4) ) (2) (HL1 = naringenin; HL2 = hesperetin) were obtained, in which an anionic flavonoid ligand is attached to the metal center along with 1,10-phenanthroline (phen) as co-ligand. Complexes (1) and (2)

  12. Copper(I Complexes of Mesoionic Carbene: Structural Characterization and Catalytic Hydrosilylation Reactions

    Directory of Open Access Journals (Sweden)

    Stephan Hohloch

    2015-04-01

    Full Text Available Two series of different Cu(I-complexes of “click” derived mesoionic carbenes are reported. Halide complexes of the type (MICCuI (with MIC = 1,4-(2,6-diisopropyl-phenyl-3-methyl-1,2,3-triazol-5-ylidene (for 1b, 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for 1c and cationic complexes of the general formula [Cu(MIC2]X (with MIC =1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X = CuI2− (for 2á, 1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X = BF4− (for 2a, 1,4-(2,6-diisopropylphenyl-3-methyl-1,2,3-triazol-5-ylidene, X = BF4− (for 2b, 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene, X = BF4− (for 2c have been prepared from CuI or [Cu(CH3CN4](BF4 and the corresponding ligands, respectively. All complexes were characterized by elemental analysis and standard spectroscopic methods. Complexes 2á and 1b were studied by single-crystal X-ray diffraction analysis. Structural analysis revealed 2á to adopt a cationic form as [Cu(MIC2](CuI2 and comparison of the NMR spectra of 2á and 2a confirmed this conformation in solution. In contrast, after crystallization complex 1b was found to adopt the desired neutral form. All complexes were tested for the reduction of cyclohexanone under hydrosilylation condition at elevated temperatures. These complexes were found to be efficient catalysts for this reaction. 2c was also found to catalyze this reaction at room temperature. Mechanistic studies have been carried out as well.

  13. XAFS study of copper(II) complexes with square planar and square pyramidal coordination geometries

    Science.gov (United States)

    Gaur, A.; Klysubun, W.; Nitin Nair, N.; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2016-08-01

    X-ray absorption fine structure of six Cu(II) complexes, Cu2(Clna)4 2H2O (1), Cu2(ac)4 2H2O (2), Cu2(phac)4 (pyz) (3), Cu2(bpy)2(na)2 H2O (ClO4) (4), Cu2(teen)4(OH)2(ClO4)2 (5) and Cu2(tmen)4(OH)2(ClO4)2 (6) (where ac, phac, pyz, bpy, na, teen, tmen = acetate, phenyl acetate, pyrazole, bipyridine, nicotinic acid, tetraethyethylenediamine, tetramethylethylenediamine, respectively), which were supposed to have square pyramidal and square planar coordination geometries have been investigated. The differences observed in the X-ray absorption near edge structure (XANES) features of the standard compounds having four, five and six coordination geometry points towards presence of square planar and square pyramidal geometry around Cu centre in the studied complexes. The presence of intense pre-edge feature in the spectra of four complexes, 1-4, indicates square pyramidal coordination. Another important XANES feature, present in complexes 5 and 6, is prominent shoulder in the rising part of edge whose intensity decreases in the presence of axial ligands and thus indicates four coordination in these complexes. Ab initio calculations were carried out for square planar and square pyramidal Cu centres to observe the variation of 4p density of states in the presence and absence of axial ligands. To determine the number and distance of scattering atoms around Cu centre in the complexes, EXAFS analysis has been done using the paths obtained from Cu(II) oxide model and an axial Cu-O path from model of a square pyramidal complex. The results obtained from EXAFS analysis have been reported which confirmed the inference drawn from XANES features. Thus, it has been shown that these paths from model of a standard compound can be used to determine the structural parameters for complexes having unknown structure.

  14. Heteroleptic copper(I) complexes prepared from phenanthroline and bis-phosphine ligands.

    Science.gov (United States)

    Kaeser, Adrien; Mohankumar, Meera; Mohanraj, John; Monti, Filippo; Holler, Michel; Cid, Juan-José; Moudam, Omar; Nierengarten, Iwona; Karmazin-Brelot, Lydia; Duhayon, Carine; Delavaux-Nicot, Béatrice; Armaroli, Nicola; Nierengarten, Jean-François

    2013-10-21

    Preparation of [Cu(NN)(PP)](+) derivatives has been systematically investigated starting from two libraries of phenanthroline (NN) derivatives and bis-phosphine (PP) ligands, namely, (A) 1,10-phenanthroline (phen), neocuproine (2,9-dimethyl-1,10-phenanthroline, dmp), bathophenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 2,9-diphenethyl-1,10-phenanthroline (dpep), and 2,9-diphenyl-1,10-phenanthroline (dpp); (B) bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)benzene (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppFc), and bis[(2-diphenylphosphino)phenyl] ether (POP). Whatever the bis-phosphine ligand, stable heteroleptic [Cu(NN)(PP)](+) complexes are obtained from the 2,9-unsubstituted-1,10-phenanthroline ligands (phen and Bphen). By contrast, heteroleptic complexes obtained from dmp and dpep are stable in the solid state, but a dynamic ligand exchange reaction is systematically observed in solution, and the homoleptic/heteroleptic ratio is highly dependent on the bis-phosphine ligand. Detailed analysis revealed that the dynamic equilibrium resulting from ligand exchange reactions is mainly influenced by the relative thermodynamic stability of the different possible complexes. Finally, in the case of dpp, only homoleptic complexes were obtained whatever the bis-phosphine ligand. Obviously, steric effects resulting from the presence of the bulky phenyl rings on the dpp ligand destabilize the heteroleptic [Cu(NN)(PP)](+) complexes. In addition to the remarkable thermodynamic stability of [Cu(dpp)2]BF4, this negative steric effect drives the dynamic complexation scenario toward almost exclusive formation of homoleptic [Cu(NN)2](+) and [Cu(PP)2](+) complexes. This work provides the definitive rationalization of the stability of [Cu(NN)(PP)](+) complexes, marking the way for future developments in this field.

  15. CFD simulation and experimental investigation of the copper solvent extraction in a pilot plant pulsed packed column in Sarcheshmeh Copper Complex

    Science.gov (United States)

    Mirzaie, Maryam; Sarrafi, Amir; Hashemipour, Hasan; Baghaie, Ali; Molaeinasab, Mehdi

    2017-06-01

    Present work deals with the development of a computational fluid dynamics (CFD) model for investigate the extraction of copper from leach solution with the Lix84-I. The model is based on Eulerian-Eulerian two phase equations in conjunction with the realizable k-ɛ model for turbulence. Population balance modeling (PBM) is used to describe the dynamics of the time and space variation of droplet sizes in the column. The PBM equation is solved using the class method. The mass transfer is the important parameters which can improve the performance of pulsed column and changes widely with the variation in the droplet number density. Valid empirical correlations were implemented to the CFD model for mass transfer coefficients by user defined functions. To validate the model, the results of CFD model and experimental measurements were compared and there was a good agreement between them. The effects of flow rates and intensity of pulsation on the yield of copper extraction and entrainment of the organic phase were studied. The results shown that increasing the phase ratio (the flow rate of organic phase/aqueous phase) from 0.5 to 1.75, caused yield of copper extraction from leach solution increased from 31 to 91%. The organic entrainment increased with increasing the pulse intensity and phase flow rates. Additionally, the results show that the performance of the pulsed packed column for copper extraction is reasonable.

  16. Spectroscopic characterization, antioxidant and antitumour studies of novel bromo substituted thiosemicarbazone and its copper(II), nickel(II) and palladium(II) complexes

    Science.gov (United States)

    Jagadeesh, M.; Lavanya, M.; Kalangi, Suresh K.; Sarala, Y.; Ramachandraiah, C.; Varada Reddy, A.

    2015-01-01

    A new, slightly distorted octahedral complex of copper(II), square planar complexes of nickel(II) and palladium(II) with 2,4‧-dibromoacetophenone thiosemicarbazone (DBAPTSC) are synthesized. The ligand and the complexes are characterized by FT-IR, FT-Raman, powder X-ray diffraction studies. The IR and Raman data are correlated for the presence of the functional groups which specifically helped in the confirmation of the compounds. In addition, the free ligand is unambiguously characterized by 1H and 13C NMR spectroscopy while the copper(II) complex is characterized by electron paramagnetic resonance spectroscopy (EPR). The g values for the same are found to be 2.246 (g1), 2.012 (g2) and 2.005 (g3) which suggested rhombic distortions. The HOMO-LUMO band gap calculations for these compounds are found to be in between 0.5 and 4.0 eV and these compounds are identified as semiconducting materials. The synthesized ligand and its copper(II), nickel(II) and palladium(II) complexes are subjected to antitumour activity against the HepG2 human hepatoblastoma cell lines. Among all the compounds, nickel(II) complex is found to exert better antitumour activity with 57.6% of cytotoxicity.

  17. Binuclear copper(II) complexes with N4O3 coordinating heptadentate ligand: synthesis, structure, magnetic properties, density-functional theory study, and catecholase activity.

    Science.gov (United States)

    Banerjee, Atanu; Sarkar, Sumana; Chopra, Deepak; Colacio, Enrique; Rajak, Kajal Krishna

    2008-05-19

    The N4O3 coordinating heptadentate ligand afforded binuclear complex [Cu 2(H 2L)(mu-OH)](ClO4)2 (1) and [Cu2(L)(H2O)2]PF6 (2). In complex 1, two copper ions are held together by mu-phenoxo and mu-hydroxo bridges, whereas in complex 2, the copper centers are connected only by a mu-phenoxo bridge. In 1, both the Cu(II) centers have square pyramidal geometry (tau=0.01-0.205), whereas in the case of 2, one Cu(II) center has square pyramidal (tau=0.2517) and other one has square based pyramidal distorted trigonal bipyramidal (tau=0.54) geometry. Complexes 1 and 2 show an strong intramolecular and very weak antiferromagnetic interaction, respectively. Density-functional theory calculations were performed to establish the magneto structural correlation between the two paramagnetic copper(II) centers. Both of the complexes display a couple of one-electron reductive responses near -0.80 and -1.10 V. The complexes show significant catalytic activity at pH 8.5 on the oxidation of 3,5-di- tert-butylcatechol (3,5-DTBC) to 3,5-di- tert-butylquinone (3,5-DTBQ), and the activity measured in terms of kcat=29-37 h(-1).

  18. A new coordination mode of (E)-3-(3-hydroxyl-phenyl)-acrylic acid in copper complex: Crystal structure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xin; Zhou, Pei; Zheng, Chunying [Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing 100081 (China); Li, Hui, E-mail: lihui@bit.edu [Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing 100081 (China)

    2015-05-15

    A copper complex ([Cu(py){sub 2}(L){sub 2}]·2CH{sub 3}OH){sub n} (HL=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) (1) with acrylic acid ligand was synthesized and structurally analyzed by IR, elemental analysis, TGA and the single-crystal X-ray diffraction methods. It is the first time to find that phenolic hydroxyl of L coordinates to Cu(II). Complex 1 exhibits 1D chain by a double-bridge of ligands, and the 3D supramolecular framework in complex 1 is constructed by π–π stacking interactions and van der Waals Contacts among the 1D chains. The magnetic properties of complex 1 have been studied. - Graphical abstract: A copper complex based on (E)-3-(3-hydroxyl-phenyl)-acrylic acid in a novel coordinated way was synthesized and a ferromagnetic exchange interactions between neighboring Cu(II) ions has be achieved. - Highlights: • A new copper complex with acrylic acid ligand was synthesized and analyzed. • We find the phenolic hydroxyl of MCA ligand coordinates to metal ion firstly. • A ferromagnetic exchange interactions between Cu(II) ions has been achieved.

  19. Circulating Immune Complexes and trace elements (Copper, Iron and Selenium as markers in oral precancer and cancer : a randomised, controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Karjodkar Freny R

    2006-10-01

    Full Text Available Abstract Aim To evaluate the levels of circulating immune complexes, trace elements (copper, iron and selenium in serum of patients with oral submucous fibrosis (OSMF, oral leukoplakia (L, and oral squamous cell carcinoma (SCC, analyze the alteration and identify the best predictors amongst these parameters for disease occurrence and progression. Methods Circulating immune complexes (CIC were estimated using 37.5% Polyethylene Glycol 6000(PEG serum precipitation. Serum estimation of copper (Cu, Iron (Fe and selenium (Se was done using the Oxalyl Dihydrazide method, Colorimetric Dipyridyl method and the Differential Pulse Cathodic Stripping Voltametry respectively. Results The data analysis revealed increased circulating immune complex levels in the precancer and cancer patients. Serum copper levels showed gradual increase from precancer to cancer patients. However, serum iron levels were decreased significantly in the cancer group. Selenium levels showed marked decrease in the cancer group. Among CIC, serum, copper, iron and selenium the best predictors for the occurrence of lesions were age, serum iron, CIC, serum selenium in the decreasing order. Conclusion The present study shows that these immunological and biological markers may be associated with the pathogenesis of oral premalignant and malignant lesions and their progressions. Concerted efforts would, therefore, help in early detection, management, and monitoring the efficacy of treatment.

  20. Synthesis, spectroscopic characterization, X-ray study and in vitro cytotoxicity of 5-hydroxycoumarin derivatives and their copper complexes

    Science.gov (United States)

    Ostrowska, Kinga; Maciejewska, Dorota; Drzewiecka-Antonik, Aleksandra; Klepka, Marcin T.; Wolska, Anna; Dobrzycki, Łukasz; Sztokfisz, Alicja; Czajkowska, Agnieszka; Młynarczuk-Biały, Izabela

    2017-10-01

    We have synthesized a series of bromo derivatives of 5-hydroxycoumarin and two new Cu(II) complexes with 6-acetyl-8-bromo-5-hydroxy-4,7-dimethylcoumarin (L2) and 6-acetyl-3,8-dibromo-5-hydroxy-4,7-dimethylcoumarin (L3) ligands, designed as potential active compounds against human cancer cell lines. The elemental analysis, mass spectroscopy, NMR and infrared spectroscopy have been used for basic characterization of analyzed compounds. The X-ray crystal structure analysis for one representative organic compound, 3,6,8-tribromo-5-hydroxy-4,7-dimethylcoumarin (c) has been performed. It has shown that coumarin system is nearly planar and the Br⋯Br interaction is a very characteristic feature of the molecular association for organic ligands. The complexes, Cu(L2)2·3H2O and Cu(L3)(ClO4)·2.5H2O, have been found as four-coordinated and contain copper in the +2 oxidation state according to X-ray absorption spectroscopy. All the compounds have been screened in vitro for their cytotoxic activity against mouse fibroblast and human prostate cancer cells. The coordination products of brominated ligands have shown to be more active than the free ligands and demonstrate significant in-vitro cytotoxicity against human prostate cancer cells (DU145).

  1. Electron spin resonance and optical resonance studies on copper(II) complexes with vanadate, molybdate and tungstate anions

    Science.gov (United States)

    Singh, Raghuvir

    1983-09-01

    A series of complexes of the form Cu(An) nL x · yH 2O, where An = vanadate, molybdate or tungstate anion, L = pyridine, α-, β- or γ-picoline, n = 1 or 2; x = 1-4 and y = 0-3, have been synthesized and characterized by electron spin resonance, photoacoustic and electronic spectral studies as well as infrared spectroscopy in the solid and solution state. The different coordination sites of the ligands and anions have been interpreted from infrared and electronic spectral data. Electron spin resonance spectral data show the square planar or distorted octahedral (in a few cases five-coordinate geometry) stereochemistry around copper(II) in these complexes. Parameters such as g∥, g⊥, A∥, A⊥, , , α 2 and β 21 calculated from electron spin resonance data indicate the presence of unpaired electrons in dx2- y2 or dz2 orbitals. The results of electronic and photoacoustic spectral studies are in good accord with ESR data.

  2. Silver and Copper Complexes with closo-Polyhedral Borane, Carborane and Metallacarborane Anions: Synthesis and X-ray Structure

    Directory of Open Access Journals (Sweden)

    Varvara V. Avdeeva

    2016-05-01

    Full Text Available Synthesis and structure of silver and copper salts and complexes with polyhedral boron hydride anions, including closo-decaborate [B10H10]2−, closo-dodecaborate [B12H12]2−, 1-carba-closo- decaborate [1-CB9H10]−, carba-closo-dodecaborate [CB11H12]−, and cobalt bis(dicarbollide [3,3′-Co(1,2-C2B9H112]− anions and their derivatives, are reviewed. The complexes demonstrate a wide variety of structural types, relating to both the metal coordination environment and coordination modes of boron hydride anions. The latter can range from strong coordination via the polyhedron triangular face including formation of 3c-2e MHB bonds in the case of the [B10H10]2− dianion, the structure of which contains two four-coordinated boron atoms, to very weak M…H interactions with the hydride atoms in the case of bulky [3,3′-Co(1,2-C2B9H112]− monoanion.

  3. Copper II - polar amino acid complexes: toxicity to bacteria and larvae of Aedes aegypti

    Directory of Open Access Journals (Sweden)

    THIAGO A.D. RODRIGUES

    Full Text Available ABSTRACT Control strategies using insecticides are sometimes ineffective due to the resistance of the insect vectors.In this scenario new products must be proposed for the control of insect vectors.The complexes L-aspartate Cu (II and L-glutamate-Cu (II complexes were synthesized and characterized by elemental analysis, visible ultraviolet, infrared spectroscopy and potentiometric titration. The toxicity of these complexes was analyzed in Aedes aegypti (Diptera: Culicidae larvae and Gram-negative and Gram-positive bacteria. The interaction between the ligands and the amino acid balance and the distribution of the species as a function of pH were discussed. The lethal concentration median (LC50 for Ae. aegypti larvae were: L-glutamic acid-Cu (II - 53.401 mg L-1 and L-aspartate-Cu (II - 108.647 mg L-1. The minimum inhibitory concentration (MIC required for Staphylococcus aureus and Escherichia coli was: L-glutamate-Cu (II 500-2000 mg L-1 and L-aspartate-Cu (II 1000-2000 mg L-1. The concentrations demonstrated toxicity that evidence the potential of the complexes as bactericide and insecticide. Metal complexes formed by amino acids and transition metals are advantageous because of low environmental toxicity, biodegradability and low production cost.

  4. A series of copper complexes with carbazole and oxadiazole moieties: Synthesis, characterization and luminescence performance

    Energy Technology Data Exchange (ETDEWEB)

    Bai Weiyang, E-mail: baiwy02@163.com [College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054 (China); Sun Li [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)

    2012-10-15

    In this paper, various moieties of ethyl, carbazole and oxadiazole are attached to 2-thiazol-4-yl-1H-benzoimidazole to form a series of diamine ligands. Their corresponding Cu(I) complexes are also synthesized using bis(2-(diphenylphosphanyl)phenyl) ether as the auxiliary ligand. Crystal structures, thermal property, electronic nature and luminescence property of these Cu(I) complexes are discussed in detail. These Cu(I) complexes are found to be efficient green-emitting ones in solutions and the emissive parameters are improved largely by the incorporation of substituent moieties. Detailed analysis suggests that the effective suppression of solvent-induced exciplex quenching is responsible for this phenomenon. On the other hand, the introduction of substituent moieties exerts no obvious influence on molecular structure, thermal stability and emitting-energy of the Cu(I) complexes, owing to their absence from inner coordination sphere. - Highlights: Black-Right-Pointing-Pointer Diamine ligands with various moieties and Cu(I) complexes are synthesized. Black-Right-Pointing-Pointer Crystal structures and photophysical property are discussed in detail. Black-Right-Pointing-Pointer The incorporation of substituent moieties improves luminescence performance. Black-Right-Pointing-Pointer Solvent-induced exciplex quenching is suppressed by substituent moieties.

  5. Ternary complexes of copper(II) and cobalt(II) involving nitrite/pyrazole and tetradentate N4-coordinate ligand: Synthesis, characterization, structures and antimicrobial activity

    Science.gov (United States)

    Solanki, Ankita; Sadhu, Mehul H.; Kumar, Sujit Baran

    2015-12-01

    Five new mononuclear mixed ligand complexes of the type [Cu(NCCH3)(dbdmp)](ClO4)2, [M(ONO)(dbdmp)]ClO4, [M(pz) (dbdmp)](ClO4)2 where M = Cu(II) and Co(II), pz = 3,5-dimethylpyrazole and dbdmp = N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine have been synthesized and characterized by physico-chemical and spectroscopy studies. The crystal structures of three copper(II) complexes [Cu(NCCH3)(dbdmp)](ClO4)2, [Cu(ONO)(dbdmp)]ClO4 and [Cu(pz)(dbdmp)](ClO4)2 have been determined by single crystal X-ray diffraction studies. Structural analyses reveal the geometry of [Cu(pz)(dbdmp)](ClO4)2 is distorted square pyramidal and other two copper(II) complexes have distorted trigonal bipyramidal geometry. Molecular composition of cobalt(II) complexes have been determined by mass spectral data. The EPR spectra of copper(II) complexes in frozen acetonitrile solution exhibit axial spectra, characteristic of dx2-y2 ground state. Electrochemical studies of copper(II) complexes using glassy carbon as working electrode in acetonitrile solution show Cu(II)/Cu(I) couple with quasi reversible electron transfer versus Ag/Ag+ reference electrode. Antimicrobial activity of all the synthesized complexes were investigated against two Gram positive and two Gram negative bacterial strains.

  6. Antimicrobial Activity of Some Thiourea Derivatives and Their Nickel and Copper Complexes

    Directory of Open Access Journals (Sweden)

    Cevdet Akbay

    2009-01-01

    Full Text Available Five thiourea derivative ligands and their Ni2+ and Cu2+ complexes have been synthesized. The compounds were screened for their in vitro anti-bacterial activity using Gram-positive bacteria (two different standard strains of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes, Bacillus cereus and Gram-negative bacteria (Esherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Proteus vulgaris, Enterobacter aerogenes and in vitro anti-yeast activity (Candida albicans, Candida krusei, Candida glabrata, Candida tropicalis, Candida parapsilosis. The minimum inhibitory concentration was determined for all ligands and their complexes. In vitro anti-yeast activity of both ligands and their metal complexes is greater than their in vitro anti-bacterial activity. The effect of the structure of the investigated compounds on the antimicrobial activity is discussed.

  7. C{sub 2}-symmetric Copper(II) complexes as chiral Lewis acids

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D.A.; Murry, J.A.; Matt, P. von [Harvard Univ., Cambridge, MA (United States)] [and others

    1995-12-01

    Two new Cu(II)-derived Lewis acid catalysts 1 and 2 have been prepared and their utility as catalysts in the Diels-Alder reaction documented. While complex 1 is effective in catalyzing the cycloaddition of unsaturated aldehyde dienophiles with cyclopentadiene complex 2 is optimal for imide dienophiles. This study provides a rational basis for the design of Lewis acids based on the coordinating capacity of cationic Cu(II) complexes which possess sufficient Lewis acidity to catalyze a range of synthetically useful Diels-Alder reactions. In particular, documentation of the importance of counterion structure in the use of cationic metal centers as Lewis acids has been made for the first time.

  8. Preconcentration and Determination of Copper and Zinc in Natural Water Samples by ICP-AES After Complexation and Sorption on Amberlite XAD-2

    Directory of Open Access Journals (Sweden)

    Ferreira Sérgio Luis Costa

    1998-01-01

    Full Text Available The present paper describes a procedure for separation, preconcentration and sequential determination of trace amounts of copper and zinc in natural water samples, by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES. The proposed method is based on the complexation of copper(II and zinc(II ions by 1-(2-thiazolylazo-2-naphthol (TAN and sorption on to Amberlite XAD-2 resin. Parameters such as: TAN amount, pH effect on the complexation and sorption of TAN complexes, agitation time for complete sorption, concentration of metal ion, mass of Amberlite XAD-2, desorption of metal ions from XAD-2 resin and sample volume were studied. The results demonstrated that the copper(II and zinc(II ions, in the range of 0.10 to 100.00 mug, contained in a solution sample volume of 400 mL, in the pH range of 5.7 to 8.3, on the form of TAN complexes had been quantitatively retained on to XAD-2 resin. The shaking time required for sorption is 1 h using a resin mass of 1.4 g. The solution for determination of copper and zinc by ICP-AES is obtained, after desorption of the ions from the XAD-2 resin, using 5 mL of 2 mol L-1 hydrochloric acid and shaking the system for 5 min. The procedure was applied to the determination of copper and zinc in several natural water samples. The standard addition technique was applied and the obtained recoveries revealed that the proposed procedure has a good accuracy. A high enrichment factor (80 and simplicity are the main advantages in this analytical protocol.

  9. 1D coordination polymers formed by tetranuclear lead(II) building blocks with carboxylate ligands: In situ isomerization of itaconic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Abhinandan; Jana, Swapan Kumar; Datta, Sayanti [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721 102, West Bengal (India); Butcher, Raymond J. [Department of Chemistry, Howard University, Washington, DC (United States); Zangrando, Ennio [Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste (Italy); Dalai, Sudipta, E-mail: sudipta@mail.vidyasagar.ac.in [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721 102, West Bengal (India)

    2013-11-15

    The synthesis of two new lead(II) coordination polymers, [Pb{sub 2}(mpic){sub 4}(H{sub 2}O)]·0.5H{sub 2}O (1) and [Pb{sub 2}(phen){sub 2}(cit)(mes)]·2H{sub 2}O (2) has been reported, where mpic=3-methyl picolinate, phen=o-phenanthroline, H{sub 2}cit=citraconic acid, H{sub 2}mes mesaconic acid. X-ray single crystal diffraction analyses showed that the complexes comprise topologically different 1D polymeric chains stabilized by weak interactions and both containing tetranuclear Pb{sub 4} units connected by carboxylate groups. In compound 1 3-methylpicolinic acid is formed in situ from 3-methyl piconitrile, and mesaconate and citraconate anions were surprisingly formed from itaconic acid during the synthesis of 2. The photoluminescence and thermal properties of the complexes have been studied. - Graphical abstract: Two new topologically different 1D coordination polymers formed by Pb{sub 4} clusters have been synthesized and characterized by X-ray analysis. The luminescence and thermal properties have been studied. Display Omitted - Highlights: • Both the complexes, made up of different ligands, forms topologycally different 1D polymeric chains containing Pb{sub 4} clusters. • The final structures are stabilized by weak interactions (H-bond, π∙∙∙π stacking). • In complex 1, the 3-methylpicolinic acid is generated in situ from 3-methyl piconitrile. • Mesaconate and citraconate anions are surprisingly formed in situ from itaconic acid during the synthesis of complex 2, indicating an exceptional transformation.

  10. N-heterocyclic carbene gold(I) and copper(I) complexes in C-H bond activation.

    Science.gov (United States)

    Gaillard, Sylvain; Cazin, Catherine S J; Nolan, Steven P

    2012-06-19

    complexes are possible. These different C-H bond activation modes provide chemists with several synthetic options. In this Account, we discuss recent discoveries involving the versatile NHC-gold(I) and NHC-copper(I) hydroxide complexes (where NHC is N-heterocyclic carbene) showing interesting Brønsted basic properties for C-H bond activation or C-H bond functionalization purposes. The simple and easy synthesis of these two complexes involves their halide-bearing relatives reacting with simple alkali metal hydroxides. These complexes can react cleanly with organic compounds bearing protons with compatible pK(a) values, producing only water as byproduct. It is a very simple protocol indeed and may be sold as a C-H bond activation, although the less flashy "metalation reaction" also accurately describes the process. The synthesis of these complexes has led us to develop new organometallic chemistry and catalysis involving C-H bond activation (metalation) and subsequent C-H bond functionalization. We further highlight applications with these reactions, in areas such as photoluminescence and biological activities of NHC-gold(I) and NHC-copper(I) complexes.

  11. Structure and magnetic properties of a new binuclear copper(II) complex of a tripodal oxime

    Science.gov (United States)

    Premužić, Dejan; Korabik, Maria; Hołyńska, Małgorzata

    2014-02-01

    Perchlorate salt of a new binuclear [Cu2] cationic complex (1) with tris(1-propan-2-onyl oxime)amine acting as a ligand is introduced. In each complex cation two Cu2+ cations are linked by oxime groups from two ligands, whereas two remaining oxime groups per ligand remain non-deprotonated and participate in bifurcated O-H⋯O hydrogen bonds. Cu2+ ions are strongly antiferromagnetically coupled with singlet-triplet energy gap of about 2J = -750 cm-1, giving rise to interesting EPR properties.

  12. Copper(II) and lead(II) complexation by humic acid and humic-like ligands

    OpenAIRE

    IVANA KOSTIĆ; TATJANA ANĐELKOVIĆ; RUŽICA NIKOLIĆ; ALEKSANDAR BOJIĆ; MILOVAN PURENOVIĆ; SRĐAN BLAGOJEVIĆ; DARKO ANĐELKOVIĆ

    2011-01-01

    The stability of metal–humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II) and Pb(II) with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25 °C and at an ionic strength of 0.01 mol dm-3 (NaCl) using the Schubert ion-exchange method and its modified form....

  13. In Vitro Activity of Copper(II) Complexes, Loaded or Unloaded into a Nanostructured Lipid System, against Mycobacterium tuberculosis

    Science.gov (United States)

    da Silva, Patricia B.; de Souza, Paula C.; Calixto, Giovana Maria Fioramonti; Lopes, Erica de O.; Frem, Regina C. G.; Netto, Adelino V. G.; Mauro, Antonio E.; Pavan, Fernando R.; Chorilli, Marlus

    2016-01-01

    Tuberculosis (TB) is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb), presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS) composed of 10% phase oil (cholesterol), 10% surfactant (soy phosphatidylcholine, sodium oleate), and Eumulgin® HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8), and an 80% aqueous phase (phosphate buffer pH = 7.4) as a tactic to enhance the in vitro anti-Mtb activity of the copper(II) complexes [CuCl2(INH)2]·H2O (1), [Cu(NCS)2(INH)2]·5H2O (2) and [Cu(NCO)2(INH)2]·4H2O (3). The Cu(II) complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI) varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from −0.00690 ± 0.0896 to −8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H37Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI) was calculated using the cytotoxicity index (IC50) against Vero (ATCC® CCL-81), J774A.1 (ATCC® TIB-67), and MRC-5 (ATCC® CCL-171) cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.). These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB. PMID:27196901

  14. In Vitro Activity of Copper(II Complexes, Loaded or Unloaded into a Nanostructured Lipid System, against Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Patricia B. da Silva

    2016-05-01

    Full Text Available Tuberculosis (TB is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb, presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS composed of 10% phase oil (cholesterol, 10% surfactant (soy phosphatidylcholine, sodium oleate, and Eumulgin® HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8, and an 80% aqueous phase (phosphate buffer pH = 7.4 as a tactic to enhance the in vitro anti-Mtb activity of the copper(II complexes [CuCl2(INH2]·H2O (1, [Cu(NCS2(INH2]·5H2O (2 and [Cu(NCO2(INH2]·4H2O (3. The Cu(II complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from −0.00690 ± 0.0896 to −8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H37Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI was calculated using the cytotoxicity index (IC50 against Vero (ATCC® CCL-81, J774A.1 (ATCC® TIB-67, and MRC-5 (ATCC® CCL-171 cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.. These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB.

  15. Synthesis, magnetostructural correlation, and catalytic promiscuity of unsymmetric dinuclear copper(II) complexes: models for catechol oxidases and hydrolases.

    Science.gov (United States)

    Osório, Renata E H M B; Peralta, Rosely A; Bortoluzzi, Adailton J; de Almeida, Vicente R; Szpoganicz, Bruno; Fischer, Franciele L; Terenzi, Hernán; Mangrich, Antonio S; Mantovani, Karen Mary; Ferreira, Dalva E C; Rocha, Willian R; Haase, Wolfgang; Tomkowicz, Zbigniew; dos Anjos, Ademir; Neves, Ademir

    2012-02-06

    Herein, we report the synthesis and characterization, through elemental analysis, electronic spectroscopy, electrochemistry, potentiometric titration, electron paramagnetic resonance, and magnetochemistry, of two dinuclear copper(II) complexes, using the unsymmetrical ligands N',N',N-tris(2-pyridylmethyl)-N-(2-hydroxy-3,5-di-tert-butylbenzyl)-1,3-propanediamin-2-ol (L1) and N',N'-bis(2-pyridylmethyl)-N,N-(2-hydroxybenzyl)(2-hydroxy-3,5-di-tert-butylbenzyl)-1,3-propanediamin-2-ol (L2). The structures of the complexes [Cu(2)(L1)(μ-OAc)](ClO(4))(2)·(CH(3))(2)CHOH (1) and [Cu(2)(L2)(μ-OAc)](ClO(4))·H(2)O·(CH(3))(2)CHOH (2) were determined by X-ray crystallography. The complex [Cu(2)(L3)(μ-OAc)](2+) [3; L3 = N-(2-hydroxybenzyl)-N',N',N-tris(2-pyridylmethyl)-1,3-propanediamin-2-ol] was included in this study for comparison purposes only (Neves et al. Inorg. Chim. Acta2005, 358, 1807-1822). Magnetic data show that the Cu(II) centers in 1 and 2 are antiferromagnetically coupled and that the difference in the exchange coupling J found for these complexes (J = -4.3 cm(-1) for 1 and J = -40.0 cm(-1) for 2) is a function of the Cu-O-Cu bridging angle. In addition, 1 and 2 were tested as catalysts in the oxidation of the model substrate 3,5-di-tert-butylcatechol and can be considered as functional models for catechol oxidase. Because these complexes possess labile sites in their structures and in solution they have a potential nucleophile constituted by a terminal Cu(II)-bound hydroxo group, their activity toward hydrolysis of the model substrate 2,4-bis(dinitrophenyl)phosphate and DNA was also investigated. Double electrophilic activation of the phosphodiester by monodentate coordination to the Cu(II) center that contains the phenol group with tert-butyl substituents and hydrogen bonding of the protonated phenol with the phosphate O atom are proposed to increase the hydrolase activity (K(ass.) and k(cat.)) of 1 and 2 in comparison with that found for complex 3. In fact

  16. DNA interaction, antimicrobial studies of newly synthesized copper (II) complexes with 2-amino-6-(trifluoromethoxy)benzothiazole Schiff base ligands.

    Science.gov (United States)

    Rambabu, Aveli; Pradeep Kumar, Marri; Tejaswi, Somapangu; Vamsikrishna, Narendrula; Shivaraj

    2016-12-01

    Four novel Schiff base ligands, L 1 (1-((E)-(6-(trifluoromethoxy)benzo[d]thiazol-2-ylimino)methyl)naphthalen-2-ol, C 19 H 11 F 3 N 2 O 2 S), L 2 (3-((E)-(6-(trifluoromethoxy)benzo[d]thiazol-2-ylimino)methyl)benzene-1,2-diol, C 15 H 9 F 3 N 2 O 3 S), L 3 (2-((E)-(6-(trifluoromethoxy)benzo[d]thiazol-2-ylimino)methyl)-5-methoxyphenol, C 16 H 11 F 3 N 2 O 3 S) and L 4 (2-((E)-(6-(trifluoromethoxy)benzo[d]thiazol-2-ylimino)methyl)-4-bromophenol, C 15 H 8 BrF 3 N 2 O 2 S) and their binary copper(II) complexes 1 [Cu(L 1 ) 2 ], 2 [Cu(L 2 ) 2 ], 3 [Cu(L 3 ) 2 ] and 4 [Cu(L 4 ) 2 ] have been synthesized and characterized by elemental analysis, 1 H NMR, 13 C NMR, ESI mass, FT-IR, ESR, UV-Visible, magnetic susceptibility, TGA, SEM and powder XRD studies. Based on spectral and analytical data, a square planar geometry is assigned for all Cu(II) complexes. The ligands and their Cu(II) complexes have been screened for antimicrobial activity against bacterial species E. coli, P. aeruginosa, B. amyloliquefaciens and S. aureus and fungal species S. rolfsii and M. phaseolina and it is observed that all Cu(II) complexes are more potent than corresponding ligands. DNA binding (UV absorption, fluorescence and viscosity titrations) and cleavage (oxidative and photo cleavage) studies of Cu(II) complexes have also been investigated against calf thymus DNA (CT-DNA) and supercoiled pBR322 DNA respectively. From the experimental results, it is found that the complexes bound effectively to CT-DNA through an intercalative mode and also cleaved pBR322 DNA in an efficient manner. The DNA binding and cleavage affinities of newly synthesized Cu(II) complexes are in the order of 2>1>3>4. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Copper (II) complexes of the anti-inflammatory drug naproxen and 3-pyridylmethanol as auxiliary ligand. Characterization, superoxide dismutase and catecholase--mimetic activities.

    Science.gov (United States)

    Abuhijleh, A Latif; Khalaf, Juhienah

    2010-09-01

    The synthesis and spectral characterization of binary copper (II) complex of the non-steroidal anti-inflammatory drug naproxen (Nap) with formula [Cu(2)(Nap)(4)](n) (1) and its ternary complex with 3-pyridylmethanol (3-pym) of formula [Cu(Nap)(2)(3-pym)(2)](n) (2) were investigated. Complex 1 is polymeric consisting of units of the known paddle-wheel dicopper (II) tetracarboxylates of four naproxenate ions bridging the two copper atoms. The units are axially connected through the neighboring carboxylate oxygen atoms. The X-ray molecular structure measurements of complex 2 showed that it is polymeric consisting of mononuclear units having trans-CuN(2)O(2) + O(2) chromophores which are bridged by 3-pyridylmethanol ligands through their methanolic oxygen atoms. The measured superoxide dismutase (SOD) mimetic activities of the complexes indicated that complexes 1 and 2 are excellent SOD mimics with an IC(50) of 0.30 microM for complex 1 and 0.39 microM for complex 2. The catecholase activities of the complexes toward the aerobic oxidation of 3,5-di-tert-butylcatechol (DTBC) to 3,5-di-tert-butylquinone (DTBQ) showed that both complexes have moderate catalytic oxidase activities. 2010 Elsevier Masson SAS. All rights reserved.

  18. Extraordinary stability of copper(I)-tetrathiomolybdate complexes: possible implications for aquatic ecosystems.

    Science.gov (United States)

    Helz, George R; Erickson, Britt E

    2011-01-01

    An extraordinary affinity of MoS₄²⁻ for Cu accounts for Mo-induced Cu deficiency in ruminants (molybdenosis) and offers an approach to treating Wilson's disease in humans. Evidence of thiomolybdates in sulfidic natural waters, and possibly even as metastable traces in oxic natural waters, raises the question of how Cu-Mo affinity might affect Cu availability or toxicity in aquatic ecosystems. Stabilities of inorganic Cu-MoS₄²⁻ complexes are characterized and quantified here for the first time. Two remarkably stable Cu(I) dissolved complexes are identified (T = 23°C ± 2°C): Cu₂(HS)₂MoS₄²⁻ and Cu₂S₂MoS₄⁴⁻. In addition, the solubility constant for a precipitate (NH₄CuMoS₄) was measured. Under the extremely reducing conditions in rumen fluids, these complexes will greatly suppress Cu(+) activity, supporting prior conclusions about the mechanism of molybdenosis. In sulfidic natural waters, they help to prevent complete Cu impoverishment, as might otherwise occur by sulfide mineral precipitation. On the other hand, the complexes discovered here are HS⁻-dependent and could not be important in oxic natural waters (with HS⁻ concentrations < 10⁻⁹ M) even if metastable, biogenic MoS₄²⁻ indeed were present as previously conjectured. © 2010 SETAC.

  19. Anion receptors containing coordinatively unsaturated metal ions: copper(II) complexes with cyclam derivatives

    National Research Council Canada - National Science Library

    Fabbrizzi, Luigi; Fusco, Nadia; Mangano, Carlo; Broglia, Arturo; Boiocchi, Massimo

    2014-01-01

    .... The formation of a five-cordinate complex is favored by the trans-I configuration of the [Cu(Bn 4 cyclam)] 2+ receptor, but it is contrasted by the severe steric repulsions exerted by the benzyl substituents on the macrocyclic framework...

  20. Enantioselectivity Measurements of Copper(II) Amino Acid Complexes Using Isothermal Titration Calorimetry

    NARCIS (Netherlands)

    Bruin, de T.J.M.; Marcelis, A.T.M.; Zuilhof, H.; Sudhölter, E.J.R.

    2000-01-01

    Enantioselectivity experiments for the binding to chiral Cu(II) complexes have been performed for several -amino acids using isothermal titration calorimetry. To a system containing nonionic micelles, Cu(II) ions, and cholesteryl glutamate as chiral selector, either the D- or L-amino acid was

  1. Copper(II) nickel(II), cobalt(II) and oxovanadium(IV) complexes of ...

    Indian Academy of Sciences (India)

    Administrator

    phenyl)-. 1-phenyl-5-(phenyl-methylene)-2-naphthalenecarboxamide (X = H, CH3, OCH3. Cl)] have been prepared and characterized on the basis of elemental analysis, magnetic moments, i.e., EPR and electronic spectra. These metal complexes ...

  2. Synthesis, structure and reactivity of a water-soluble copper(I) complex

    Indian Academy of Sciences (India)

    Administrator

    Water-soluble phosphines and their complexes have attracted a great deal of interest because of their potential use in aqueous catalytic organometallic chemistry and biomedical applications. Tris(hydroxymethyl)phosphine (THP) is moderately air-stable and water-soluble. While the coordination chemistry of this ligand with ...

  3. Stereochemical diversity of {MNO}(10) complexes: molecular orbital analyses of nickel and copper nitrosyls.

    Science.gov (United States)

    Conradie, Jeanet; Ghosh, Abhik

    2014-05-19

    The great majority of {NiNO}(10) complexes are characterized by short Ni-N(O) distances of 1.60-1.65 Å and linear NO units. Against this backdrop, the {CuNO}(10) unit in the recently reported [Cu(CH3NO2)5(NO)](2+) cation (1) has a CuNO angle of about 120° and a very long 1.96 Å Cu-N(O) bond. According to DFT calculations, metal-NO bonding in 1 consists of a single Cu(dz(2))-NO(π*) σ-interaction and essentially no metal(dπ)-NO(π*) π-bonding, which explains both the bent CuNO geometry and the long, weak Cu-N(O) bond. This σ-interaction is strongly favored by a ligand trans to the NO; indeed such a trans ligand may be critical for the existence and stability of a {CuNO}(10) unit. By contrast, {NiNO}(10) complexes exhibit a strong avoidance of such trans ligands. Thus, a five-coordinate {NiNO}(10) complex appears to favor a trigonal-bipyramidal structure with the NO in an equatorial position, as in the case of [Ni(bipy)2(NO)](+) (6). An unusual set of Ni(d)-NO(π*) orbital interactions accounts for the strongly bent NiNO geometry for this complex.

  4. Mesogenic copper (II) complexes with [1, 2, 3]-triazole-based ...

    Indian Academy of Sciences (India)

    The first mesogenic Cu(II) complex with [1,2,3]-triazole-based bidentate Schiff bases with flexible terminal alkyl chain, CnH2n+1 (even parity of n = 10-18) has been successfully synthesized. The heterocyclic triazole core was introduced into the target compound through the click reaction between azidoalkane and propargyl ...

  5. Coordination Chemistry of Polyaromatic Thiosemicarbazones 2: Synthesis and Biological Activity of Zinc, Cobalt, and Copper Complexes of 1-(Naphthalene-2-ylethanone Thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    Marc-Andre LeBlanc

    2011-01-01

    Full Text Available A novel thiosemicarbazone from 2-acetonaphthone (represented as acnTSC has been synthesized and its basic coordination chemistry with zinc(II, cobalt(II, and copper(II explored. The complexes were characterized by elemental analysis and various spectroscopic techniques and are best formulated as [M(acnTSC2Cl2] with the metal likely in an octahedral environment. The anticancer activity of the complexes was determined against a panel of human colon cancer cells (HCT-116 and Caco-2. The compounds bind to DNA via an intercalative mode with binding constants of 9.7×104 M-1, 1.8×105 M-1, and 9.5×104 M-1 for the zinc, cobalt, and copper complexes, respectively.

  6. Iron(III and copper(II complexes bearing 8-quinolinol with amino-acids mixed ligands: Synthesis, characterization and antibacterial investigation

    Directory of Open Access Journals (Sweden)

    Saliu A. Amolegbe

    2015-09-01

    Full Text Available Four d-orbital metal complexes with mixed ligands derived from 8-hydroxyquinoline (HQ and amino acids (AA: l-alanine and methionine have been synthesized through a mild reflux in alkaline solution and characterized by elemental analyses, infrared, electronic transition, and temperature dependant magnetic susceptibility. The IR spectroscopy revealed that iron and copper ions coordinated through carbonyl (CO, hydroxyl group (OH of the amino acids, N-pyridine ring of hydroxyquinoline. The elemental analysis measurement with other obtained data suggested an octahedral geometry for the iron(III complexes and tetrahedral geometry for the copper(II complexes. From the molar magnetic susceptibility measurement, the iron(III system (S = 5/2 d5 (non-degenerate 6A1 with χmT = 0.38 cm3 Kmol−1 showed an antiferromagnetic while Cu2+ ions system (S = ½ (2T2g has χmT = 4.77 cm3 Kmol−1 described as paramagnetic behaviour. In vitro antimicrobial investigations of the metal complexes against standard bacteria species gave significant inhibition with, copper complex showing highest inhibitions against Pseudomonas aeruginosa (ATCC27853 of 43 mm at 10 μg/ml signalling its potential as pharmaceutical or chemotherapeutic agents.

  7. Antimicrobial mechanism of copper (II 1,10-phenanthroline and 2,2′-bipyridyl complex on bacterial and fungal pathogens

    Directory of Open Access Journals (Sweden)

    S. Chandraleka

    2014-12-01

    Full Text Available Copper based metallo drugs were prepared and their antibacterial, antifungal, molecular mechanism of [Cu(SAlaPhen]·H2O and [Cu(SAlabpy]·H2O complexes were investigated. The [Cu(SAlaPhen]·H2O and [Cu(SAlabpy]·H2O were derived from the Schiff base alanine salicylaldehyde. [Cu(SAlaPhen]·H2O showed noteworthy antibacterial and antifungal activity than the [Cu(SAlabpy]·H2O and ligand alanine, salicylaldehyde. The [Cu(SAlaPhen]·H2O complex showed significant antibacterial activity against Salmonella typhi, Staphylococcus aureus, Salmonella paratyphi and the antifungal activity against Candida albicans and Cryptococcus neoformans in well diffusion assay. The mode of action of copper (II complex was analyzed by DNA cleavage activity and in silico molecular docking. The present findings provide important insight into the molecular mechanism of copper (II complexes in susceptible bacterial and fungal pathogens. These results collectively support the use of [Cu(SAlaPhen]·H2O complex as a suitable drug to treat bacterial and fungal infections.

  8. Preparation of CuO nanoparticles by thermal decomposition of double-helical dinuclear copper(II Schiff-base complexes

    Directory of Open Access Journals (Sweden)

    Aliakbar Dehno Khalaji

    2015-12-01

    Full Text Available In this paper, two double helical dinuclear copper(II complexes of bis-N,O-bidentate Schiff base ligands bis(3-methoxy-N-salicylidene-4,4'-diaminodiphenylsulfone (L1 and bis(5-bromo-N-salicylidene-4,4'-diaminodiphenylsulfone (L2 were prepared and characterized by elemental analyses (CHN, as well as thermal analysis. Elemental analyses (CHN suggested that the reaction between ligands and copper salt has been occurred in 1:1 molar ratio. In these complexes the Schiff base ligands behaves as an anionic and bis-bidentate chelate and is coordinated to the copper(II ion via two phenolic oxygen and two iminic nitrogen atoms. In these double helical dinuclear complexes, each copper(II center has a pseudo-tetrahedral coordination sphere two-wrapped ligands. Thermal analysis of ligands and their complexes were studied in the range of room temperature to 750 °C with a heating rate of 10 °C min-1. TG plots show that the ligands and their complexes are thermally decomposed via 2 and 3 thermal steps, respectively. In addition, the complexes thermally decomposed in air at 520 °C for 3 h. The obtained solids characterized by Fourier transform infrared spectroscopy (FT-IR, X-ray powder diffraction (XRD and transmission electron microscopy (TEM. The X-ray pattern result shows that the CuO nanoparticles are pure and single phase. The TEM result shows the as prepared CuO nanoparticles were very small and similar shape with particle size about

  9. In vitro DNA binding studies of the sweetening agent saccharin and its copper(II) and zinc(II) complexes.

    Science.gov (United States)

    Icsel, Ceyda; Yilmaz, Veysel T

    2014-01-05

    The interactions of fish sperm DNA (FS-DNA) with the sodium salt of sweetener saccharin (sacH) and its copper and zinc complexes, namely [M(sac)2(H2O)4]·2H2O (M=Cu(II) or Zn(II)) were studied by using UV-Vis titration, fluorometric competition, thermal denaturation, viscosity and gel electrophoresis measurements. The intrinsic binding constants (Kb) obtained from absorption titrations were estimated to be 2.86 (±0.06)×10(4)M(-1) for Na(sac), 6.67 (±0.12)×10(4)M(-1) for Cu-sac and 4.01 (±0.08)×10(4)M(-1) for Zn-sac. The Cu-sac complex binds to FS-DNA via intercalation with a KA value of 50.12 (±0.22)×10(4)M(-1) as evidenced by competitive binding studies with ethidium bromide. Moreover, competition experiments with Hoechst 33258 are indicative of a groove binding mode of Na(sac) and Zn-sac with binding constants of 3.13 (±0.16)×10(4)M(-1) and 5.25 (±0.22)×10(4)M(-1), respectively. The spectroscopic measurements indicate a moderate DNA binding affinity of Na(sac) and its metal complexes. The suggested binding modes are further confirmed by the thermal denaturation and viscosity measurements. In addition, Cu-sac and Zn-sac show weak ability to damage to pBR322 supercoiled plasmid DNA. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Nitrene transfer reactions catalysed by copper(I) complexes in ionic liquid using chloramine-T.

    Science.gov (United States)

    Cano, Israel; Nicasio, M Carmen; Pérez, Pedro J

    2009-01-28

    The complex [Tpm(*,Br)Cu(NCMe)]BF4 (Tpm(*,Br) = HC(3,5-Me2-4-Br-pyrazolyl)3) catalyses the aziridination of alkenes and the amidation of cyclic ethers with chloramine-T as the nitrene source and the ionic liquid [bmim]PF6 as the reaction medium (bmim = 1-n-butyl-3-methylimidazolium). High conversions have been obtained over several cycles of catalyst recovery and reuse.

  11. Synthesis, spectral characterization and biological evaluation of copper(II) and nickel(II) complexes with thiosemicarbazones derived from a bidentate Schiff base

    Science.gov (United States)

    Chandra, Sulekh; Bargujar, Savita; Nirwal, Rita; Yadav, Neesha

    2013-04-01

    Complexes of copper(II) and nickel(II) of general composition M(L)2X2, have been synthesized with the ligand 1-Tetralone thiosemicarbazone (where L = 1-Tetralone thiosemicarbazone and X=Cl,1/2SO42-). The molar conductance of the complexes in fresh solution of DMSO lies in the range of 10-20 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. Thus, the complexes may be formulated as [M(L2)X2]. Ligand was characterized by mass, NMR, IR and single crystallographic studies. All the complexes were characterized by elemental analyses, magnetic moments, IR, electronic and EPR spectral studies. The IR spectral data of ligand indicated the involvement of sulfur and azomethine nitrogen in coordination to the central metal ion. The copper(II) and nickel(II) complexes were found to have magnetic moments1.93-1.96 BM and 2.91-2.94 BM corresponding to one and two unpaired electrons respectively. On the basis of molar conductance, EPR, electronic and infrared spectral studies, a tetragonal geometry has been assigned for Cu(II) chloride complex and trigonal bipyramidal to Cu(II) sulfate complex but an octahedral geometry for Ni(II) complexes. Newly synthesized ligand and its Cu(II) and Ni(II) complexes have also been screened against different bacterial and fungal species.

  12. Synthesis of mononuclear copper(II) complexes of N3O2 and N4O2 donors containing Schiff base ligands: Theoretical and biological observations

    Science.gov (United States)

    Mancha Madha, K.; Gurumoorthy, P.; Arul Antony, S.; Ramalakshmi, N.

    2017-09-01

    A new series of six mononuclear copper(II) complexes were synthesized from N3O2 and N4O2 donors containing Schiff base ligands, and characterized by various spectral methods. The geometry of the complexes was determined using UV-Vis, EPR and DFT calculations. The complexes of N3O2 donors (1-3) adopted square pyramidal geometry and the remaining complexes of N4O2 donors (4-6) show distorted octahedral geometry around copper(II) nuclei. Redox properties of the complexes show a one-electron irreversible reduction process in the cathodic potential (Epc) region from -0.74 to -0.98 V. The complexes show potent antioxidant activity against DPPH radicals. Molecular docking studies of complexes showed σ-π interaction, hydrogen bonding, electrostatic and van der Waals interactions with VEGFR2 kinase receptor. In vitro cytotoxicity of the complexes was tested against human breast cancer (MDA-MB-231) cell lines and one normal human dermal fibroblasts (NHDF) cell line through MTT assay. The morphological assessment data obtained by Hoechst 33258 and AO/EB staining revealed that the complexes induce apoptosis pathway of cell death.

  13. Ligand Synthesis Catalyst and Complex Metal Ion: Multicomponent Synthesis of 1,3-Bis(4-phenyl-[1,2,3]triazol-1-yl-propan-2-ol Copper(I Complex and Application in Copper-Catalyzed Alkyne-Azide Cycloaddition

    Directory of Open Access Journals (Sweden)

    María Teresa Ramírez-Palma

    2016-01-01

    Full Text Available A new bistriazole copper complex was synthesized by direct treatment of an alkyne, an azide, and CuI as copper salt through in situ ligand formation under a multicomponent reaction process. This complex was analyzed by XPS, TGA, DSC, and SEM techniques and revealed a triangular-shaped morphology, high thermal stability, and catalytic power in CuAAC reactions, requiring only 2.5% mol catalyst to afford 1,2,3-triazoles in good yields which can be reused at least for 4 cycles.

  14. New copper(II) complexes with dopamine hydrochloride and vanillymandelic acid: Spectroscopic and thermal characterization

    Science.gov (United States)

    Mohamed, Gehad G.; Nour El-Dien, F. A.; El-Nahas, R. G.

    2011-10-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. The Cu(II) chelates with coupled products of dopamine hydrochloride (DO.HCl) and vanillymandelic acid (VMA) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical techniques namely IR, magnetic and UV-vis spectra are used to investigate the structure of these chelates. Cu(II) forms 1:1 (Cu:DO) and 1:2 (Cu:VMA) chelates. DO behave as a uninegative tridentate ligand in binding to the Cu(II) ion while VMA behaves as a uninegative bidentate ligand. IR spectra show that the DO is coordinated to the Cu(II) ion in a tridentate manner with ONO donor sites of the phenolic- OH, -NH and carbonyl- O, while VMA is coordinated with OO donor sites of the phenolic- OH and -NH. Magnetic moment measurements reveal the presence of Cu(II) chelates in octahedral and square planar geometries with DO and VMA, respectively. The thermal decomposition of Cu(II) complexes is studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  15. DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole

    Science.gov (United States)

    Li, Mei; kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

    2014-07-01

    A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV-vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV-vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells.

  16. DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole.

    Science.gov (United States)

    Li, Mei; Kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

    2014-07-15

    A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV-vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV-vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Defining the Electronic And Geometric Structure of One-Electron Oxidized Copper-Bis-Phenoxide Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Storr, T.; Verma, P.; Pratt, R.C.; Wasinger, E.C.; Shimazaki, Y.; Stack, T.D.P.

    2009-05-26

    The geometric and electronic structure of an oxidized Cu complex ([CuSal](+); Sal = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) with a non-innocent salen ligand has been investigated both in the solid state and in solution. Integration of information from UV-vis-NIR spectroscopy, magnetic susceptibility, electrochemistry, resonance Raman spectroscopy, X-ray crystallography, X-ray absorption spectroscopy, and density functional theory calculations provides critical insights into the nature of the localization/delocalization of the oxidation locus. In contrast to the analogous Ni derivative [NiSal](+) (Storr, T.; et al. Angew. Chem., Int. Ed. 2007, 46, 5198), which exists solely in the Ni(II) ligand-radical form, the locus of oxidation is metal-based for [CuSal](+), affording exclusively a Cu(III) species in the solid state (4-300 K). Variable-temperature solution studies suggest that [CuSal](+) exists in a reversible spin-equilibrium between a ligand-radical species [Cu(II)Sal(*)](+) (S = 1) and the high-valent metal form [Cu(III)Sal](+) (S = 0), indicative of nearly isoenergetic species. It is surprising that a bis-imine-bis-phenolate ligation stabilizes the Cu(III) oxidation state, and even more surprising that in solution a spin equilibrium occurs without a change in coordination number. The oxidized tetrahydrosalen analogue [CuSal(red)](+) (Sal(red) = N,N'-bis(3,5-di- tert-butylhydroxybenzyl)-1,2-cyclohexane-(1R,2R)-diamine) exists as a temperature-invariant Cu(II)-ligand-radical complex in solution, demonstrating that ostensibly simple variations of the ligand structure affect the locus of oxidation in Cu-bis-phenoxide complexes.

  18. Defining the electronic and geometric structure of one-electron oxidized copper-bis-phenoxide complexes.

    Science.gov (United States)

    Storr, Tim; Verma, Pratik; Pratt, Russell C; Wasinger, Erik C; Shimazaki, Yuichi; Stack, T Daniel P

    2008-11-19

    The geometric and electronic structure of an oxidized Cu complex ([CuSal](+); Sal = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) with a non-innocent salen ligand has been investigated both in the solid state and in solution. Integration of information from UV-vis-NIR spectroscopy, magnetic susceptibility, electrochemistry, resonance Raman spectroscopy, X-ray crystallography, X-ray absorption spectroscopy, and density functional theory calculations provides critical insights into the nature of the localization/delocalization of the oxidation locus. In contrast to the analogous Ni derivative [NiSal](+) (Storr, T.; et al. Angew. Chem., Int. Ed. 2007, 46, 5198), which exists solely in the Ni(II) ligand-radical form, the locus of oxidation is metal-based for [CuSal](+), affording exclusively a Cu(III) species in the solid state (4-300 K). Variable-temperature solution studies suggest that [CuSal](+) exists in a reversible spin-equilibrium between a ligand-radical species [Cu(II)Sal(*)](+) (S = 1) and the high-valent metal form [Cu(III)Sal](+) (S = 0), indicative of nearly isoenergetic species. It is surprising that a bis-imine-bis-phenolate ligation stabilizes the Cu(III) oxidation state, and even more surprising that in solution a spin equilibrium occurs without a change in coordination number. The oxidized tetrahydrosalen analogue [CuSal(red)](+) (Sal(red) = N,N'-bis(3,5-di- tert-butylhydroxybenzyl)-1,2-cyclohexane-(1R,2R)-diamine) exists as a temperature-invariant Cu(II)-ligand-radical complex in solution, demonstrating that ostensibly simple variations of the ligand structure affect the locus of oxidation in Cu-bis-phenoxide complexes.

  19. A rapid extractive spectrophotometric determination of copper(II) in environmental samples, alloys, complexes and pharmaceutical samples using 4-[N,N(dimethyl)amino]benzaldehyde thiosemicarbazone.

    Science.gov (United States)

    Karthikeyan, J; Naik, P Parameshwara; Shetty, A Nityananda

    2011-05-01

    4-[N,N-(Dimethyl)amino]benzaldehyde thiosemicarbazone (DMABT) is proposed as an analytical reagent for the extractive spectrophotometric determination of copper(II). DMABT forms yellow colored complex with copper(II) in the pH range 4.4-5.4. Beer's law is obeyed in the concentration range up to 4.7 μg mL(-1). The optimum concentration range for minimum photometric error as determined by Ringbom plot method is 1.2-3.8 μg mL(-1). The yellowish Cu(II)-DMABT complex shows a maximum absorbance at 420 nm, with molar absorptivity of 1.72 × 10(4)dm(3) mol(-1) cm(-1) and Sandell's sensitivity of the complex obtained from Beer's data is 0.0036 μg cm(-2). The composition of the Cu(II)-DMABT complex is found to be 1:2 (M/L). The interference of various cations and anions in the method were studied. Thus the method can be employed for the determination of trace amount of copper(II) in water, alloys and other natural samples of significant importance.

  20. Synthetic and structural studies on copper 1 H-[1,10]-phenanthrolin-2-one coordination complexes: isolation of a novel intermediate during 1,10-phenanthroline hydroxylation.

    Science.gov (United States)

    Szpakolski, Katherine B; Latham, Kay; Rix, Colin J; White, Jonathan M; Moubaraki, Boujemaa; Murray, Keith S

    2010-02-01

    The synthesis and crystal structure elucidation of a novel dinuclear heteroleptic copper(II) complex has led to an alternative mechanism in the formation of covalent hydrates. During further studies on the synthesis and properties of [Cu(2)(ophen)(2)] (1), a dinuclear complex of copper(I) with 1 H-[1,10]-phenanthrolin-2-one (Hophen), two intermediates/alternative products 2 and 3 were isolated. The dinuclear, antiferromagnetic complex [Cu(2)(ophen)(2)(phen)(2)](NO(3))(2)9H(2)O (3, phen=1,10-phenanthroline) contains two five-coordinate copper(II) ions, both with trigonal-bipyramidal coordination, which are bridged together through deprotonated hydroxyl groups with a Cu--Cu non-bonding distance of 3.100 A. Complex [Cu(phen)(2)(H(2)O)](NO(3))(2) (2) is a polymorph of a previously reported material. The occurrence of 2 and 3 has led us to propose a variation to the Gillard mechanism for the formation of covalent hydrates in bidentate N-heterocycles in which the attacking nucleophile may be the deprotonated form of 2, [Cu(phen)(2)(OH)](-), rather than free OH(-).

  1. Synthesis and characterization of new copper(I) complexes containing 4-(diphenylphosphane)benzoic acid and "scorpionate" ligands with "in vitro" superoxide scavenging activity.

    Science.gov (United States)

    Santini, Carlo; Pellei, Maura; Lobbia, Giancarlo Gioia; Fedeli, Donatella; Falcioni, Giancarlo

    2003-04-01

    New copper(I) complexes have been synthesised from the reaction of CuCl with 4-(diphenylphosphane)benzoic acid and lithium tris(1H-pyrazol-1-yl)methanesulfonate, Li(SO(3))C(pz)(3), sodium hydrotris(3-trifluoromethyl-1H-pyrazol-1-yl)borate, NaHB[3-(CF(3))pz](3), potassium dihydrobis(1H-1,2,4-triazol-1-yl)borate, KH(2)B(tz)(2), hydrotris(1H-1,2,4-triazol-1-yl)borate, KHB(tz)(3), sodium hydrotris(1H-pyrazol-1-yl)borate, NaHB(pz)(3), potassium hydrotris(3,5-dimethyl-1H-pyrazol-1-yl)borate KHB(3,5-Me(2)Pz)(3) or potassium hydrotris(4-bromo-1H-pyrazol-1-yl)borate KHB(4-Brpz)(3). The complexes obtained have been characterized by elemental analyses and FT-IR in the solid state, and by NMR (1H and 31P[(1)H]) spectroscopy and conductivity measurements in solution. The solution data are consistent with partial dissociation of the sterically hindered complexes by way of breaking of Cu-P and Cu-N bonds. Electrospray mass spectrometry has been used to investigate the relative properties of the 4-(diphenylphosphane)benzoic acid and of the "scorpionate" ligands towards copper(I) ions. Chemiluminescence technique was used to evaluate the superoxide scavenging activity of these new copper complexes. Copyright 2003 Elsevier Science Inc.

  2. Extreme pollution of soils by emissions of the copper-nickel industrial complex in the Kola Peninsula

    Science.gov (United States)

    Kashulina, G. M.

    2017-07-01

    The distribution of the total Ni, Cu, Co, Cd, Pb, and Zn contents was studied in the soil profiles of six catenas in the zone subjected to emissions of the copper-nickel industrial complex, which is the largest source of SO2 and heavy metals in northern Europe. The results show that, at present, the concentrations of Ni and Cu in the upper organic soil horizons in the impact zone reach extreme levels of 9000 and 6000 mg/kg, respectively. Under conditions of the long-term intense multi-element industrial emissions, the modern levels of the accumulation of polluting substances in soils greatly depend on the indirect factors, such as the degree of the technogenic degradation of soils with the loss of a significant part of soil organic matter, the reaching of threshold saturation of the topsoil with polluting metals, and competitive relationships between chemical elements. The state of the ecosystems in the impact zone varied greatly and did not always agree with the contents of the main metals-pollutants in the soils. The moisture conditions determined by the landscape position affected significantly the resistance of the ecosystems to emissions.

  3. Synthesis, Characterization, and Biological Studies of Binuclear Copper(II Complexes of (2E-2-(2-Hydroxy-3-Methoxybenzylidene-4N-Substituted Hydrazinecarbothioamides

    Directory of Open Access Journals (Sweden)

    P. Murali Krishna

    2013-01-01

    Full Text Available Four novel binuclear copper(II complexes [1–4] of (2E-2-(2-hydroxy-3-methoxybenzylidene-4N-substituted hydrazinecarbothioamides, (OH(OCH3C6H4CH=NNHC(SNHR, where R = H (L1, Me (L2, Et (L3, or Ph (L4, have been synthesized and characterized. The FT-IR spectral data suggested the attachment of copper(II ion to ligand moiety through the azomethine nitrogen, thioketonic sulphur, and phenolic-O. The spectroscopic characterization indicates the dissociation of dimeric complex into mononuclear [Cu(LCl] units in polar solvents like DMSO, where L is monoanionic thiosemicarbazone. The DNA binding properties of the complexes with calf thymus (CT DNA were studied by spectroscopic titration. The complexes show binding affinity to CT DNA with binding constant (Kb values in the order of 106 M−1. The ligands and their metal complexes were tested for antibacterial and antifungal activities by agar disc diffusion method. Except for complex 4, all complexes showed considerable activity almost equal to the activity of ciprofloxacin. These complexes did not show any effect on Gram-negative bacteria, whereas they showed moderate activity for Gram-positive strains.

  4. Heteroleptic Copper(I) Complexes of “Scorpionate” Bis-pyrazolyl Carboxylate Ligand with Auxiliary Phosphine as Potential Anticancer Agents: An Insight into Cytotoxic Mode

    OpenAIRE

    Rais Ahmad Khan; Mohammad Usman; Rajakumar Dhivya; Perumalsamy Balaji; Ali Alsalme; Hamad AlLohedan; Farukh Arjmand; Khalid AlFarhan; Mohammad Abdulkader Akbarsha; Fabio Marchetti; Claudio Pettinari; Sartaj Tabassum

    2017-01-01

    New copper(I) complexes [CuCl(PPh3)(L)] (1: L?=?LA?=?4-carboxyphenyl)bis(3,5-dimethylpyrazolyl)methane; (2: L?=?LB?=?3-carboxyphenyl)bis(3,5-dimethylpyrazolyl)methane) were prepared and characterised by elemental analysis and various spectroscopic techniques such as FT-IR, NMR, UV?Vis, and ESI-MS. The molecular structures of complexes 1 and 2 were analyzed by theoretical B3LYP/DFT method. Furthermore, in vitro DNA binding studies were carried out to check the ability of complexes 1 and 2 to i...

  5. Synthesis, characterization and biological activities of copper(II) complex of 2-Benzimidazolyl-urea and the nitrate salt of 2-Benzimidazolyl-urea

    Science.gov (United States)

    Poyraz, Mehmet; Sari, Musa; Banti, Christina N.; Hadjikakou, Sotiris K.

    2017-10-01

    The synthesis of the complex {[Cu(BZIMU)2](NO3)2} (1) (BZIMU = 2-Benzimidazolyl-urea) is reported here. The complex 1 was characterized by elemental analysis, FT-IR, magnetic susceptibility and molar conductance measurements. The crystal structures of 1 and of the nitrate salt of [(BZIMUH+)(NO3)-] (2) were determined by X-ray diffraction analysis. The copper complex 1 and [(BZIMUH+)(NO3)-] (2) were evaluated for their in vitro cytotoxic activity (cell viability) against human cervix adenocarcinoma (HeLa) and human breast adenocarcinoma (MCF-7) cell line and normal human fetal lung fibroblast cells (MRC-5) with SRB assay.

  6. Application of a topical biomimetic electrical signaling technology to photo-aging: a randomized, double-blind, placebo-controlled trial of a galvanic zinc-copper complex.

    Science.gov (United States)

    Chantalat, Jeannette; Bruning, Elizabeth; Sun, Ying; Liu, Jue-Chen

    2012-01-01

    The first signs of facial skin photo-aging often occur in the skin of the periorbital area and include sagging, loss of firmness and definition, and sallowness. Epidermal wounds have been shown to alter the trans-epithelial electrical potential creating an electric signal that directs cell migration in epithelial wound healing; this electric field declines sharply with age. A topical galvanic zinc-copper complex, which couples elemental zinc and copper to create a biomimetic electric field, has demonstrated anti-inflammatory activity and extracellular matrix improvement in vitro, including collagen and elastin production. To evaluate the efficacy and tolerability of a galvanic zinc-copper complex on photo-aging parameters in a randomized, double-blind, placebo-controlled clinical trial. In this eight-week study, women (40-65 years) with mild to moderate photo-aging were randomized to use placebo or 1 of 3 galvanic zinc-copper complex compositions (gel and activating moisturizer). Efficacy evaluations included clinical grading, specialized clinical imaging, and subject self-assessments performed at baseline, 15-30 minutes after product application and after 1, 2, 4, and 8 weeks. Tolerability was based on adverse events and clinical grading of irritation. Significance was set at P?0.05 versus baseline and between treatment groups. The study was completed by 124 women. Compositions containing the galvanic zinc-copper complex showed statistically significant clinical improvements versus placebo and baseline rapidly (15-30 min) after application and through week 8. Clinical grading showed significant improvement versus placebo in skin radiance and under-eye dark circles 15-30 minutes after first application with continued improvement through week 8, and in overall photo-damage, fine lines, lifted appearance of the eyes, and under-eye wrinkles starting after two weeks and continuing through week 8. Test compositions were well tolerated. This galvanic zinc-copper complex

  7. Influence of ocean acidification on the organic complexation of iron and copper in Northwest European shelf seas; a combined observational and model study

    Directory of Open Access Journals (Sweden)

    Lizeth eAvendaño

    2016-04-01

    Full Text Available The pH of aqueous solutions is known to impact the chemical speciation of trace metals. In this study we conducted titrations of coastal seawaters with iron and copper at pH 7.91, 7.37 and 6.99 (expressed on the total pH scale. Changes in the concentration of iron and copper that complexed with the added ligands 1-nitroso-2-napthol and salicylaldoxime respectively were determined by adsorptive cathodic stripping voltammetry - competitive ligand equilibrium (AdCSV-CLE. Interpretation of the results, assuming complexation by a low concentration of discrete ligands, showed that conditional stability constants for iron complexes increased relative to inorganic iron complexation as pH decreased by approximately 1 log unit per pH unit, whilst those for copper did not change. No trend was observed for concentrations of iron and copper complexing ligands over the pH range examined. We also interpreted our titration data by describing chemical binding and polyelectrolytic effects using non-ideal competitive adsorption in Donnan-like gels (NICA-Donnan model in a proof of concept study. The NICA-Donnan approach allows for the development of a set of model parameters that are independent of ionic strength and pH, and thus calculation of metal speciation can be undertaken at ambient sample pH or the pH of a future, more acidic ocean. There is currently a lack of basic NICA-Donnan parameters applicable to marine dissolved organic matter (DOM so we assumed that the measured marine dissolved organic carbon could be characterized as terrestrial fulvic acids. Generic NICA-Donnan parameters were applied within the framework of the software program visual MINTEQ and the metal –added ligand concentrations [MeAL] calculated for the AdCSV-CLE conditions. For copper, calculated [MeAL] using the NICA-Donnan model for DOM were consistent with measured [MeAL], but for iron an inert fraction with kinetically inhibited dissolution was required in addition to the NICA

  8. Synthesis, electron paramagnetic resonance studies and molecular calculations of N-aminopyrimidine salicylaldiminato copper (II) complex

    Science.gov (United States)

    Yalçın, Şerife Pınar; Ceylan, Ümit; Sönmez, Mehmet; Hacıyusufoğlu, Mehmet Emin; Karavelioğlu, Hatice

    2017-11-01

    In this study, Cu(II) complex, C52H40CuN6O10, was synthesized and the molecular structure was characterized by experimental Electron Paramagnetic Resonance (EPR), vibrational frequencies, absorption wavelengths and compared with theoretical methods. The molecular geometry was calculated and optimized by using Gaussian 09 software and DFT-B3LYP and B3PW91 methods with the LanL2DZ basis sets in ground state. The theoretical vibrational frequencies, was optimized geometric parameters such as bond lengths, bond angles and torsion angles and absorption wavelengths, NBO, FMO analysis, HOMO-LUMO energy and nonlinear optical properties, molecular electrostatic potential, spin density have been calculated via quantum chemical methods. Theoretically calculated data were compared with experimentally measured data. Also, the results obtained by using the two basis sets were compared with each other.

  9. A novel Schiff base derived from the gabapentin drug and copper (II) complex: Synthesis, characterization, interaction with DNA/protein and cytotoxic activity.

    Science.gov (United States)

    Shokohi-Pour, Zahra; Chiniforoshan, Hossein; Momtazi-Borojeni, Amir Abbas; Notash, Behrouz

    2016-09-01

    A novel Schiff base [C20H23NO3], has been prepared and characterized using FT-IR, UV-vis, (1)H NMR spectroscopy, elemental analysis and X-ray crystallography. A copper (II) complex [Cu(C20H22NO3)2]·H2O has also been synthesized and characterized. The new ligand and complex thus obtained were investigated by their interaction with calf thymus DNA and BSA using electronic absorption spectroscopy, fluorescence spectroscopy, and thermal denaturation. The intrinsic binding constants Kb of the ligand and Cu (II) complex, with CT-DNA obtained from UV-vis absorption studies were 1.53×10(4)M(-1) and 3.71×10(5)M(-1), respectively. Moreover the addition of the two compounds to CT-DNA (1:2) led to an increase of the melting temperature of DNA up to around 2.61°C for the ligand and 3.99°C for the Cu (II) complex. The ligand and Cu (II) complex bind to CT-DNA via a partial intercalative, as shown by the experimental data. In addition, the albumin interactions of the two compounds were studied by fluorescence quenching spectra, the results indicating that the binding mechanism is a static quenching process. The in vitro cytotoxicity of the two compounds on three different cancer cell lines was evaluated by MTT assay. The results showed that the copper complex exerted enhanced cytotoxicity compared with the Schiff base ligand; thereby, this complex clearly implies a positive synergistic effect. Furthermore, the copper complex showed a high, selective, and dose-dependent cytotoxicity against cancer cell lines. Copyright © 2016. Published by Elsevier B.V.

  10. Synthesis, CMC Determination, Antimicrobial Activity and Nucleic Acid Binding of A Surfactant Copper(II) Complex Containing Phenanthroline and Alanine Schiff-Base.

    Science.gov (United States)

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-03-01

    A new water-soluble surfactant copper(II) complex [Cu(sal-ala)(phen)(DA)] (sal-ala = salicylalanine, phen = 1,10-phenanthroline, DA = dodecylamine), has been synthesized and characterized by physico-chemical and spectroscopic methods. The critical micelle concentration (CMC) values of this surfactant-copper(II) complex in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308, 313. 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG(0)m, ΔH(0)m and ΔS(0)m). The interaction of this complex with nucleic acids (DNA and RNA) has been explored by using electronic absorption spectral titration, competitive binding experiment, cyclic voltammetry, circular dichroism (CD) spectra, and viscosity measurements. Electronic absorption studies have revealed that the complex can bind to nucleic acids by the intercalative binding mode which has been verified by viscosity measurements. The DNA binding constants have also been calculated (Kb = 1.2 × 10(5) M(-1) for DNA and Kb = 1.6 × 10(5) M(-1) for RNA). Competitive binding study with ethidium bromide (EB) showed that the complex exhibits the ability to displace the DNA-bound-EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. The presence of hydrophobic ligands, alanine Schiff-base, phenanthroline and long aliphatic chain amine in the complex were responsible for this strong intercalative binding. The surfactant-copper (II) complex was screened for its antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, amikacin(antibacterial) and ketokonazole(antifungal).

  11. Poly(N-4-vinylbenzyl-1,4,7-triazacyclononane Copper Complex Grafted Solid Catalyst for Oxidative Polymerization of 2,6-Dimethylphenol

    Directory of Open Access Journals (Sweden)

    Kei Saito

    2016-01-01

    Full Text Available A new solid phase catalyst, poly(N-4-vinylbenzyl-1,4,7-triazacyclononane copper(I complex, grafted onto polystyrene particles, has been employed for the oxidative polymerization of 2,6-dimethylphenol using an aqueous biphasic (water/toluene solvent system. The solid catalyst was synthesized by first grafting N-(4-vinylbenzyl-1,4,7-triaza-cyclononane onto polystyrene particles using a radical mediated polymerization method and next by creating the polymer-metal complex of copper-triazacyclononane with these modified particles. Poly(2,6-dimethyl-1,4-phenylene oxide was successfully obtained from the polymerization of 2,6-dimethylphenol using this new metal-organic solid phase catalyst.

  12. Synthesis, characterization and catalytic oxidation properties of multi-wall carbon nanotubes with a covalently attached copper(II) salen complex

    Science.gov (United States)

    Salavati-Niasari, Masoud; Bazarganipour, Mehdi

    2009-06-01

    Hydroxyl functionalized copper(II) Schiff-base, N,N'-bis(4-hydroxysalicylidene)-ethylene-1,2-diaminecopper(II), [Cu((OH) 2-salen)], has been covalently anchored on modified MWCNTs. The new modified MWCNTs ([Cu((OH) 2-salen)]-MWCNTs) have been characterized by TEM, thermal analysis, XRD, XPS, UV-vis, DRS, FT-IR spectroscopy and elemental analysis. The modified copper(II) MWCNTs solid was used to affect the catalytic oxidation of ethylbenzene with tert-butylhydroperoxide as the oxidant at 333 K. The system is truly heterogeneous (no leaching observed) and reusable (no decrease in activity) in three consecutive runs. Acetophenone was the major product though small amounts of o- and p-hydroxyacetophenones were also formed revealing that C-H bond activation takes place both at benzylic and aromatic ring carbon atoms. Ring hydroxylation was more over the "neat" complexes than over the encapsulated complexes.

  13. Synthesis, characterization and catalytic oxidation properties of multi-wall carbon nanotubes with a covalently attached copper(II) salen complex

    Energy Technology Data Exchange (ETDEWEB)

    Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Department of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Bazarganipour, Mehdi [Department of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of)

    2009-06-15

    Hydroxyl functionalized copper(II) Schiff-base, N,N'-bis(4-hydroxysalicylidene)-ethylene-1,2-diaminecopper(II), [Cu((OH){sub 2}-salen)], has been covalently anchored on modified MWCNTs. The new modified MWCNTs ([Cu((OH){sub 2}-salen)]-MWCNTs) have been characterized by TEM, thermal analysis, XRD, XPS, UV-vis, DRS, FT-IR spectroscopy and elemental analysis. The modified copper(II) MWCNTs solid was used to affect the catalytic oxidation of ethylbenzene with tert-butylhydroperoxide as the oxidant at 333 K. The system is truly heterogeneous (no leaching observed) and reusable (no decrease in activity) in three consecutive runs. Acetophenone was the major product though small amounts of o- and p-hydroxyacetophenones were also formed revealing that C-H bond activation takes place both at benzylic and aromatic ring carbon atoms. Ring hydroxylation was more over the 'neat' complexes than over the encapsulated complexes.

  14. Formation constants of copper(II) complexes with tripeptides containing Glu, Gly, and His: potentiometric measurements and modeling by generalized multiplicative analysis of variance.

    Science.gov (United States)

    Khoury, Rima Raffoul; Sutton, Gordon J; Ebrahimi, Diako; Hibbert, D Brynn

    2014-02-03

    We report a systematic study of the effects of types and positions of amino acid residues of tripeptides on the formation constants logβ, acid dissociation constants pKa, and the copper coordination modes of the copper(II) complexes with 27 tripeptides formed from the amino acids glutamic acid, glycine, and histidine. logβ values were calculated from pH titrations with l mmol L(-1):1 mmol L(-1) solutions of the metal and ligand and previously reported ligand pKa values. Generalized multiplicative analysis of variance (GEMANOVA) was used to model the logβ values of the saturated, most protonated, monoprotonated, logβ(CuL) - logβ(HL), and pKa of the amide group. The resulting model of the saturated copper species has a two-term model describing an interaction between the central and the C-terminal residues plus a smaller, main effect of the N-terminal residue. The model supports the conclusion that two copper coordination modes exist depending on the absence or presence of His at the central position, giving species in which copper is coordinated via two or three fused chelate rings, respectively. The GEMANOVA model for pKamide, which is the same as that for the saturated complex, showed that Gly-Gly-His has the lowest pKamide values among the 27 tripeptides. Visible spectroscopy indicated the formation of metal-ligand dimers for tripeptides His-His-Gly and His-His-Glu, but not for His-His-His, and the formation of multiple ligand bis compexes CuL2 and Cu(HL)2 for tripeptides (Glu/Gly)-His-(Glu/Gly) and His-(Glu/Gly)-(Glu/Gly), respectively.

  15. Synthesis and structure of new tetracopper(II) complexes with N-benzoate-N'-[3-(diethylamino)propyl]oxamide as a bridging ligand: The influence of hydrophobicity on enhanced DNA/BSA-binding and anticancer activity.

    Science.gov (United States)

    Fu, Hong-Lei; Zheng, Kang; Zhang, Mei-Jiao; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2016-08-01

    Two new tetracopper(II) complexes bridged by N-benzoate-N'-[3-(diethylamino)propyl]oxamide (H3bdpox), and ended with 4,4'-dimethyl-2,2'-bipyridine (Me2bpy) or 2,2'-bipyridine (bpy), namely [Cu4(bdpox)2(Me2bpy)2](pic)2 (1) and [Cu4(bdpox)2(bpy)2](pic)2·2H2O (2) (where pic denotes the picrate anion) have been synthesized and characterized by X-ray single-crystal diffraction and other methods. In both complexes, four copper(II) ions are bridged alternately by the cis-oxamido and the carboxylato groups of two bdpox(3-) ligands to form a centrosymmetric cyclic tetranuclear cation, in which, the copper(II) ions at the endo- and exo-sites of cis-bdpox(3-) ligand have square-planar and square-pyramidal coordination geometries, respectively. The reactivity towards DNA/BSA suggests that these complexes can interact with HS-DNA through the intercalation mode and the binding affinity varies as 1>2 depending on the hydrophobicity, and effectively quench the fluorescence of protein BSA via a static mechanism. In vitro anticancer activities showed that the two complexes are active against the selected tumor cell lines, and the anticancer activities are consistent with their DNA-binding affinity. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Inhibition of TDP-43 accumulation by bis(thiosemicarbazonato-copper complexes.

    Directory of Open Access Journals (Sweden)

    Sarah J Parker

    Full Text Available Amyotrophic lateral sclerosis (ALS is a progressive, fatal, motor neuron disease with no effective long-term treatment options. Recently, TDP-43 has been identified as a key protein in the pathogenesis of some cases of ALS. Although the role of TDP-43 in motor neuron degeneration is not yet known, TDP-43 has been shown to accumulate in RNA stress granules (SGs in cell models and in spinal cord tissue from ALS patients. The SG association may be an early pathological change to TDP-43 metabolism and as such a potential target for therapeutic intervention. Accumulation of TDP-43 in SGs induced by inhibition of mitochondrial activity can be inhibited by modulation of cellular kinase activity. We have also found that treatment of cells and animal models of neurodegeneration, including an ALS model, with bioavailable bis(thiosemicarbazonatocopper(II complexes (Cu(II(btscs can modulate kinase activity and induce neuroprotective effects. In this study we examined the effect of diacetylbis(-methylthiosemicarbazonatocopper(II (Cu(II(atsm and glyoxalbis(-methylthiosemicarbazonatocopper(II (Cu(II(gtsm on TDP-43-positive SGs induced in SH-SY5Y cells in culture. We found that the Cu(II(btscs blocked formation of TDP-43-and human antigen R (HuR-positive SGs induced by paraquat. The Cu(II(btscs protected neurons from paraquat-mediated cell death. These effects were associated with inhibition of ERK phosphorylation. Co-treatment of cultures with either Cu(II(atsm or an ERK inhibitor, PD98059 both prevented ERK activation and blocked formation of TDP-43-and HuR-positive SGs. Cu(II(atsm treatment or ERK inhibition also prevented abnormal ubiquitin accumulation in paraquat-treated cells suggesting a link between prolonged ERK activation and abnormal ubiquitin metabolism in paraquat stress and inhibition by Cu. Moreover, Cu(II(atsm reduced accumulation of C-terminal (219-414 TDP-43 in transfected SH-SY5Y cells. These results demonstrate that Cu(II(btsc complexes

  17. Study on potential antitumor mechanism of a novel Schiff base copper(II) complex: synthesis, crystal structure, DNA binding, cytotoxicity and apoptosis induction activity.

    Science.gov (United States)

    Qiao, Xin; Ma, Zhong-Ying; Xie, Cheng-Zhi; Xue, Fei; Zhang, Yan-Wen; Xu, Jing-Yuan; Qiang, Zhao-Yan; Lou, Jian-Shi; Chen, Gong-Jun; Yan, Shi-Ping

    2011-05-01

    A new cytotoxic copper(II) complex with Schiff base ligand [Cu(II)(5-Cl-pap)(OAc)(H(2)O)]·2H(2)O (1) (5-Cl-pap=N-2-pyridiylmethylidene-2-hydroxy-5-chloro-phenylamine), was synthesized and structurally characterized by X-ray diffraction. Single-crystal analysis revealed that the copper atom shows a 4+1 pyramidal coordination, a water oxygen appears in the apical position, and three of the basal positions are occupied by the NNO tridentate ligand and the fourth by an acetate oxygen. The interaction of Schiff base copper(II) complex 1 with DNA was investigated by UV-visible spectra, fluorescence spectra and agarose gel electrophoresis. The apparent binding constant (K(app)) value of 6.40×10(5) M(-1) for 1 with DNA suggests moderate intercalative binding mode. This copper(II) complex displayed efficient oxidative cleavage of supercoiled DNA, which might indicate that the underlying mechanism involve hydroxyl radical, singlet oxygen-like species, and hydrogen peroxide as reactive oxygen species. In addition, our present work showed the antitumor effect of 1 on cell cycle and apoptosis. Flow cytometric analysis revealed that HeLa cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that complex 1 can induce apoptosis of HeLa cells, whose process was mediated by intrinsic mitochondrial apoptotic pathway owing to the activation of caspase-9 and caspase-3. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Bioinspired tannic acid-copper complexes as selective coating for nanofiltration membranes

    KAUST Repository

    Chakrabarty, Tina

    2017-04-27

    Bio-polyphenols that are present in tea, date fruits, chockolate and many other plants have been recognized as scaffold material for the manufacture of composite filtration membranes. These phenolic biomolecules possess abundant gallol (1,2,3-trihydroxyphenyl) and catechol (1,2-dihydroxyphenyl) functional groups, which allow the spontaneous formation of a thin polymerized layer at the right pH conditions. Here, we report a facile and cost-effective method to coat porous membranes via the complexation of tannic acid (TA) and cupric acetate (mono hydrate) through co-deposition. The modified membranes were investigated by XPS, ATR/FTIR, water contact angle, SEM and water permeance for a structural and morphological analysis. The obtained results reveal that the modified membranes with TA and cupric acetate (CuII) developed a thin skin layer, which showed excellent hydrophilicity with good water permeance. These membranes were tested with different molecular weight polyethylene glycols (PEG) in aqueous solution; the MWCO was around 600 Daltons.

  19. Copper(II) selective electrochemical sensor based on Schiff Base complexes.

    Science.gov (United States)

    Singh, Lok P; Bhatnagar, Jitendra M

    2004-10-08

    Plasticized membranes using Schiff Base complexes, derived from 2,3-diaminopyridine and o-vanilin have been prepared and explored as Cu(2+)-selective sensors. Effect of various plasticizers viz., dibutyl phthalate (DBP), dioctylphthalate (DOP), chloronaphthalene (CN), tri-n-butylphosphate (TBP) etc. and anion excluder, sodium tetraphenylborate (NaTPB) was studied in detail and improved performance was observed at several instances. Optimum performance was observed with Schiff Base (B) having a membrane composition of B(1%):PVC(33%):DOP(65%):NaTPB(1%). The sensor works satisfactorily in the concentration range 5.0x10(-6) to 1.0x10(-1)M (detection limit 0.3ppm) with a Nernstian slope of 29.6mV per decade of activity. Wide pH range (1.9-5.2), fast response time (4 months) indicate the vital utility of the proposed sensor. The potentiometric selectivity coefficient values as determined by match potential method (MPM) indicate good response for Cu(2+) in presence of interfering ions. The tolerance level of Hg(2+), which causes serious interference in the determination of Cu(2+) ions (K(Cu(2+)Hg(2+))(Pot)(MPM): 0.45), was determined as a function of Cu(2+) concentration in simulated mixtures. The sensor was also used in the potentiometric titration of Cu(2+) with EDTA.

  20. ROS-mediated cytotoxic effect of copper(II) hydrazone complexes against human glioma cells.

    Science.gov (United States)

    Recio Despaigne, Angel A; Da Silva, Jeferson G; da Costa, Pryscila R; Dos Santos, Raquel G; Beraldo, Heloisa

    2014-10-27

    2-Acetylpyridine acetylhydrazone (H2AcMe), 2-benzoylpyridine acetylhydrazone (H2BzMe) and complexes [Cu(H2AcMe)Cl2] (1) and [Cu(H2BzMe)Cl2] (2) were assayed for their cytotoxicity against wild type p53 U87 and mutant p53 T98 glioma cells, and against MRC-5 fibroblast cells. Compounds 1 and 2 proved to be more active than the corresponding hydrazones against U87, but not against T98 cells. Compound 1 induced higher levels of ROS than H2AcMe in both glioma cell lines. H2AcMe and 1 induced lower levels of ROS in MRC5 than in U87 cells. Compound 2 induced lower levels of ROS in MRC5 than in T98 cells. The cytotoxic effect of 1 in U87 cells could be related to its ability to provoke the release of ROS, suggesting that the cytotoxicity of 1 might be somehow p53 dependent.