Unusual saccharin-N,O (carbonyl) coordination in mixed-ligand copper(II) complexes: Synthesis, X-ray crystallography and biological activity

Science.gov (United States)

Mokhtaruddin, Nur Shuhada Mohd; Yusof, Enis Nadia Md; Ravoof, Thahira B. S. A.; Tiekink, Edward R. T.; Veerakumarasivam, Abhi; Tahir, Mohamed Ibrahim Mohamed

2017-07-01

Three tridentate Schiff bases containing N and S donor atoms were synthesized via the condensation reaction between S-2-methylbenzyldithiocarbazate with 2-acetyl-4-methylpyridine (S2APH); 4-methyl-3-thiosemicarbazide with 2-acetylpyridine (MT2APH) and 4-ethyl-3-thiosemicarbazide with 2-acetylpyridine (ET2APH). Three new, binuclear and mixed-ligand copper(II) complexes with the general formula, [Cu(sac)(L)]2 (sac = saccharinate anion; L = anion of the Schiff base) were then synthesized, and subsequently characterized by IR and UV/Vis spectroscopy as well as by molar conductivity and magnetic susceptibility measurements. The Schiff bases were also spectroscopically characterized using NMR and MS to further confirm their structures. The spectroscopic data indicated that the Schiff bases behaved as a tridentate NNS donor ligands coordinating via the pyridyl-nitrogen, azomethine-nitrogen and thiolate-sulphur atoms. Magnetic data indicated a square pyramidal environment for the complexes and the conductivity values showed that the complexes were essentially non-electrolytes in DMSO. The X-ray crystallographic analysis of one complex, [Cu(sac)(S2AP)]2 showed that the Cu(II) atom was coordinated to the thiolate-S, azomethine-N and pyridyl-N donors of the S2AP Schiff base and to the saccharinate-N from one anion, as well as to the carbonyl-O atom from a symmetry related saccharinate anion yielding a centrosymmetric binuclear complex with a penta-coordinate, square pyramidal geometry. All the copper(II) saccharinate complexes were found to display strong cytotoxic activity against the MCF-7 and MDA-MB-231 human breast cancer cell lines.

Catalytic hydrogenation using complexes of base metals with tridentate ligands

Energy Technology Data Exchange (ETDEWEB)

Hanson, Susan K.; Zhang, Guoqi; Vasudevan, Kalyan V.

2017-02-14

Complexes of cobalt and nickel with tridentate ligand PNHP.sup.R are effective for hydrogenation of unsaturated compounds. Cobalt complex [(PNHP.sup.Cy)Co(CH.sub.2SiMe.sub.3)]BAr.sup.F.sub.4 (PNHP.sup.Cy=bis[2-(dicyclohexylphosphino)ethyl]amine, BAr.sup.F.sub.4=B(3,5-(CF.sub.3).sub.2C.sub.6H.sub.3).sub.4)) was prepared and used with hydrogen for hydrogenation of alkenes, aldehydes, ketones, and imines under mild conditions (25-60.degree. C., 1-4 atm H.sub.2). Nickel complex [(PNHP.sup.Cy)Ni(H)]BPh.sub.4 was used for hydrogenation of styrene and 1-octene under mild conditions. (PNP.sup.Cy)Ni(H) was used for hydrogenating alkenes.

Catalytic hydrogenation using complexes of base metals with tridentate ligands

Energy Technology Data Exchange (ETDEWEB)

Vasudevan, Kalyan V.; Zhang, Guoqi; Hanson, Susan K.

2016-09-06

Complexes of cobalt and nickel with tridentate ligand PNHP.sup.R are effective for hydrogenation of unsaturated compounds. Cobalt complex [(PNHP.sup.Cy)Co(CH.sub.2SiMe.sub.3)]BAr.sup.F.sub.4 (PNHP.sup.Cy=bis[2-(dicyclohexylphosphino)ethyl]amine, BAr.sup.F.sub.4=B(3,5-(CF.sub.3).sub.2C.sub.6H.sub.3).sub.4)) was prepared and used with hydrogen for hydrogenation of alkenes, aldehydes, ketones, and imines under mild conditions (25-60.degree. C., 1-4 atm H.sub.2). Nickel complex [(PNHP.sup.Cy)Ni(H)]BPh.sub.4 was used for hydrogenation of styrene and 1-octene under mild conditions. (PNP.sup.Cy)Ni(H) was used for hydrogenating alkenes.

Synthesis, crystal structure, fluorescence and electrochemical studies of a new tridentate Schiff base ligand and its nickel(II) and palladium(II) complexes

Science.gov (United States)

Shafaatian, Bita; Soleymanpour, Ahmad; Kholghi Oskouei, Nasim; Notash, Behrouz; Rezvani, Seyyed Ahmad

2014-07-01

A new unsymmetrical tridentate Schiff base ligand was derived from the 1:1 M condensation of ortho-vanillin with 2-mercaptoethylamine. Nickel and palladium complexes were obtained by the reaction of the tridentate Schiff base ligand with nickel(II) acetate tetrahydrate and palladium(II) acetate in 2:1 M ratio. In nickel and palladium complexes the ligand was coordinated to metals via the imine N and enolic O atoms. The S groups of Schiff bases were not coordinated to the metals and S-S coupling was occured. The complexes have been found to possess 1:2 Metal:Ligand stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The complexes exhibited octahedral coordination geometry. The emission spectra of the ligand and its complexes were studied in methanol. Electrochemical properties of the ligand and its metal complexes were investigated in the CH3CN solvent at the 100 mV s-1 scan rate. The ligand and metal complexes showed both reversible and quasi-reversible processes at this scan rate. The Schiff base and its complexes have been characterized by IR, 1H NMR, UV/Vis, elemental analyses and conductometry. The crystal structure of nickel complex has been determined by single crystal X-ray diffraction.

A P,O,P′-tridentate mixed-donor scorpionate ligand: 6-[4,6-bis(diphenylphosphino-10H-phenoxazin-10-yl]hexan-1-ol

Directory of Open Access Journals (Sweden)

Holger B. Friedrich

2008-10-01

Full Text Available The title compound, C42H39NO2P2, is a P,O,P′-tridentate scorpionate-type ligand and has one molecule in the asymmetric unit. The angles involving the P atoms range from 100.21 (7 to 104.89 (7°. The N-hexanol group was found to be disordered and was refined over two positions with final occupancies of 0.683 (3 and 0.317 (3 which affected the C—O and C—N bond lengths. The bond lengths for C—O range from 1.402 (2 to 1.415 (2 Å and for C—N from 1.410 (2 to 1.448 (3 Å for the major disorder component; the corresponding ranges for the minor disorder component are 1.429 (3–1.408 (3 and 1.474 (3–1.474 (4 Å.

Tuning facial-meridional isomerisation in monometallic nine-co-ordinate lanthanide complexes with unsymmetrical tridentate ligands.

Science.gov (United States)

Le Borgne, Thierry; Altmann, Peter; André, Nicolas; Bünzli, Jean-Claude G; Bernardinelli, Gérald; Morgantini, Pierre-Yves; Weber, Jacques; Piguet, Claude

2004-03-07

The unsymmetrical tridentate benzimidazole-pyridine-carboxamide units in ligands L1-L4 react with trivalent lanthanides, Ln(III), to give the nine-co-ordinate triple-helical complexes [Ln(Li)3]3+ (i = 1-4) existing as mixtures of C3-symmetrical facial and C1-symmetrical meridional isomers. Although the beta13 formation constants are 3-4 orders of magnitude smaller for these complexes than those found for the D3-symmetrical analogues [Ln(Li)3]3+ (i = 5-6) with symmetrical ligands, their formation at the millimolar scale is quantitative and the emission quantum yield of [Eu(L2)3]3+ is significantly larger. The fac-[Ln(Li)3]3+ mer-[Ln(Li)3]3+ (i = 1-4) isomerisation process in acetonitrile is slow enough for Ln = Lu(III) to be quantified by 1H NMR below room temperature. The separation of enthalpic and entropic contributions shows that the distribution of the facial and meridional isomers can be tuned by the judicious peripheral substitution of the ligands affecting the interstrand interactions. Molecular mechanics (MM) calculations suggest that one supplementary interstrand pi-stacking interaction stabilises the meridional isomers, while the facial isomers benefit from more favourable electrostatic contributions. As a result of the mixture of facial and meridional isomers in solution, we were unable to obtain single crystals of 1:3 complexes, but the X-ray crystal structures of their nine-co-ordinate precursors [Eu(L1)2(CF3SO3)2(H2O)](CF3SO3)(C3H5N)2(H2O) (6, C45H54EuF9N10O13S3, monoclinic, P2(1)/c, Z = 4) and [Eu(L4)2(CF3SO3)2(H2O)](CF3SO3)(C4H4O)(1.5) (7, C51H66EuF9N8O(15.5)S3, triclinic, P1, Z = 2) provide crucial structural information on the binding mode of the unsymmetrical tridentate ligands.

Lanthanide(III) Complexes with Tridentate Schiff Base Ligand ...

African Journals Online (AJOL)

Lanthanide complexes, hydrazino, antioxidant activity, X-ray structure. 1. Introduction ... measured using a Johnson Matthey scientific magnetic suscepti- bility balance. 2.1. .... of the ligand and that the nitrogen atom supporting this proton is not involved in the ... 4f-electrons are not involved in the coordination. These facts.

Physicochemical, Spectral, and Biological Studies of Mn(II, Cu(II, Cd(II, Zr(OH2(IV, and UO2(VI Compounds with Ligand Containing Thiazolidin-4-one Moiety

Directory of Open Access Journals (Sweden)

Dinesh Kumar

2014-01-01

Full Text Available The Schiff base (I upon reacting with mercaptoacetic acid in dry benzene undergoes cyclization and forms N-(2-carbamoylthienyl-C-(3′-carboxy-2′-hydroxyphenylthiazolidin-4-one, LH3 (II. A MeOH solution of II reacts with Mn(II, Cu(II, Cd(II, Zr(OH2(IV, and UO2(VI ions and forms the coordination compounds, [Mn(LH(MeOH2], [Cu(LH]2, [Cd(LH], [Zr(OH2(OAc2(LH3], and [UO2(NO3(LH2(MeOH]. The compounds have been characterized on the basis of elemental analyses, molar conductance, molecular weight, spectral (IR, reflectance, and EPR studies and magnetic susceptibility measurements. LH3 behaves as a neutral tridentate ONS donor ligand in [Zr(OH2(OAc2(LH3], monobasic tridentate ONS donor ligand in [UO2(NO3(LH2(MeOH], dibasic tridentate OOS donor ligand in [Cu(LH]2 and dibasic tetradentate OONO donor ligand in [Mn(LH(MeOH2] and [Cd(LH]. [Cu(LH]2 is dimer, while all other compounds are monomers in diphenyl. A square-planar structure for [Cu(LH]2, a tetrahedral structure for [Cd(LH], an octahedral structure for [Mn(LH(MeOH2], a pentagonal-bipyramidal structure for [Zr(OH2(OAc2(LH3], and an eight-coordinate structure for [UO2(NO3(LH2(MeOH] are proposed. The ligand (II and its compounds show antibacterial activities towards E. coli. (Gram negative and S. aureus (Gram positive.

Stability studies on 99mTechnetium(III) complexes with tridentate/monodentate thiol ligands and phosphine ('3+1+1' complexes)

International Nuclear Information System (INIS)

Seifert, Sepp; Drews, Antje; Gupta, Antje; Pietzsch, Hans-Juergen; Spies, Hartmut; Johannsen, Bernd

2000-01-01

The preparation and characterisation of 3+1+1 technetium complexes of the general formula [Tc(SES)(RS)(PMe 2 Ph)] (SES=tridentate dithiol ligand, E=S, O, NMe; RSH=monothiol ligand) at the n.c.a. level is described. The Tc(III) complexes are prepared in a one-step procedure starting from pertechnetate in yields of 85-95% of radiochemical purity. A comparison of their chromatographic data with the fully characterised 99 Tc complexes indicate the identity of the investigated compounds. Stability studies show that the 99m Tc complexes undergo some alteration in solution. They are oxidised to the 3+1 oxotechnetium (V) complexes and/or decompose in aqueous solution. In challenge experiments performed with glutathione, exchange of the monothiolato ligand occurs in the same manner as known for the 3+1 complexes

Synthesis, Characterization and Antimicrobial Activity of Cu(II, Co(II and Ni(II Complexes with O, N, and S Donor Ligands

Directory of Open Access Journals (Sweden)

Vidyavati Reddy

2008-01-01

Full Text Available The complexes of the type ML2 [where M = Cu(II, Co(II, and Ni(II] L = 1-phenyl-1-ene-3-(2-hydroxyphenyl-prop-2-ene with 3- substituted-5-mercapto-4-amino-1,2,4-triazoles. Schiff base ligands have been prepared by reacting 3-(2-hydroxyphenyl-1-phenylprop-2-en-1-one and 3-phenyl/pyridyl-4-amino-5-mercapto-1,2,4-triazoles in an alcoholic medium. The complexes are non-electrolytes in DMF. The resulting complexes were characterized by elemental analysis, magnetic measurements, conductivity measurements and spectral studies. The Schiff base acts as a tridentate dibasic and coordinating through the deprotonated oxygen, thioenolic sulphur and azomethine nitrogen atoms. It is found that Cu(II, Co(II, and Ni(II complexes exhibited octahedral geometry. The antimicrobial activities of ligands and its complexes were screened by cup plate method.

Tridentate hydrazone metal complexes derived from cephalexin and 2-hydrazinopyridine: Synthesis, characterization and antibacterial activity

Science.gov (United States)

Anacona, J. R.; Rincones, Maria

2015-04-01

Metal(II) coordination compounds of a tridentate hydrazone ligand (HL) derived from the condensation of cephalexin antibiotic with 2-hydrazinopyridine were synthesized. The hydrazone ligand and mononuclear [ML(OAc)(H2O)] (M(II) = Mn, Co, Ni, Cu, Zn, Ag) complexes were characterized by several techniques, including elemental and thermal analysis, molar conductance and magnetic susceptibility measurements, electronic, FT-IR, EPR and 1H NMR spectral studies. The cephalexin 2-pyridinylhydrazone ligand HL behaves as a monoanionic tridentate NNO chelating agent. The biological applications of complexes have been studied on three bacteria strains (Escherichia coli, Acinetobacter baumannii and Enterococcus faecalis) by agar diffusion disc method.

Controlling the oxidation of bis-tridentate cobalt(ii) complexes having bis(2-pyridylalkyl)amines: ligand vs. metal oxidation.

Science.gov (United States)

Anjana, S; Donring, S; Sanjib, P; Varghese, B; Murthy, Narasimha N

2017-08-22

Two bis-tridentate chelated cobalt(ii) complexes, which differ in the ligand structure by a methylene group, activate molecular oxygen (O 2 ), and give different oxidation products. The O 2 reaction of [Co II (pepma) 2 ] 2+ (1) with unsymmetrical 2-(2-pyridyl)-N-(2-pyridylmethyl)ethanamine (pepma) results in ligand oxidation, to the corresponding Co(ii) imine complex [Co II (pepmi) 2 ] 2+ (2). Contrastingly, the Co(ii) complex [Co II (bpma) 2 ] 2+ (3) of similar symmetrical bis(2-pyridylmethyl)amine (bpma), undergoes metal oxidation, yielding a cobalt(iii) complex, [Co III (bpma) 2 ] 2+ (4). The reversibility of the amine to imine conversion and the stability of the Co(ii) imine complex (2) are investigated. Furthermore, the solution dynamics of Co(ii) complexes are highlighted with the help of paramagnetic 1 H-NMR spectroscopy.

New synthetic routes toward enantiopure nitrogen donor ligands.

Science.gov (United States)

Sala, Xavier; Rodríguez, Anna M; Rodríguez, Montserrat; Romero, Isabel; Parella, Teodor; von Zelewsky, Alexander; Llobet, Antoni; Benet-Buchholz, Jordi

2006-12-08

New polypyridylic chiral ligands, having either C3 or lower symmetry, have been prepared via a de novo construction of the pyridine nucleus by means of Kröhnke methodology in the key step. The chiral moieties of these ligands originate from the monoterpen chiral pool, namely (-)-alpha-pinene ((-)-14, (-)-15) and (-)-myrtenal ((-)-9, (-)-10). Extension of the above-mentioned asymmetric synthesis procedure to the preparation of enantiopure derivatives of some commonly used polypyridylic ligands has been achieved through a new aldehyde building block ((-)-16). As an example, the synthesis of a chiral derivative of N,N-bis(2-pyridylmethyl)ethylamine (bpea) ligand, (-)-19, has been performed to illustrate the viability of the method. The coordinative ability of the ligands has been tested through the synthesis and characterization of complexes [Mn((-)-19)Br2], (-)-20, and [RuCl((-)-10)(bpy)](BF4), (-)-21. Some preliminary results related to the enantioselective catalytic epoxidation of styrene with the ruthenium complex are also presented.

Selective extraction of trivalent actinides with hard-soft mixed donor ligands: role of intra-ligand synergism

International Nuclear Information System (INIS)

Ghanty, Tapan K.

2016-01-01

In recent years, considerable attention has been given to understand the coordination chemistry of trivalent lanthanide (Ln) and actinide (An) with various ligands because of its close link with the nuclear waste management processes. It is well known that lanthanide-actinide separation is a challenging and difficult task because of very similar chemical properties of these two series of ions, which are associated with similar ionic radii and coordination numbers. Recently, we have introduced a new concept, 'intra-ligand synergism', where hard donor atom, such as, oxygen preferentially binds to trivalent actinides (An(III)) as compared to the valence iso-electronic trivalent lanthanides (Ln(III)) in presence of another soft donor centre. In the present work, the conventional concept of selective complexation of actinides with soft donor ligands (either S or N donor) has been modified through exploiting this concept, and thereby the higher selectivity of 1,10-phenanthroline-2,9-dicarboxylamide (PDAM) based ligands, namely PDAM and its isobutyl and decyl derivatives towards Am(III) ion has been predicted theoretically through density functional calculations. Subsequently, several such amide derivatives have been synthesized to optimize the solubility of the ligands in organic phase. Finally, solvent extraction experiments have been carried out to validate the theoretical prediction on the selectivity of oxygen donor ligands towards Am(III) as compared to Eu(III), and a maximum separation factor of about 51 has been achieved experimentally using 2,9-bis(N-decylaminocarbonyl)-1,10-phenanthroline ligand. The separation factor is increased with the decrease in pH, which is very interesting since extraction of the Am 3+ ion is considered to be important under highly acidic conditions from the nuclear waste management point of view. (author)

New synthetic routes toward enantiopure nitrogen donor ligands

OpenAIRE

Sala, Xavier; Rodríguez, Anna M.; Rodríguez, Montserrat; Romero, Isabel; Parella, Teodor; Zelewsky, Alexander von; Llobet, Antoni; Benet-Buchholz, Jordi

2008-01-01

New polypyridylic chiral ligands, having either C₃ or lower symmetry, have been prepared via a de novo construction of the pyridine nucleus by means of Kröhnke methodology in the key step. The chiral moieties of these ligands originate from the monoterpen chiral pool, namely (-)-α-pinene ((-)-14, (-)-15) and (-)-myrtenal ((-)-9, (-)-10). Extension of the above-mentioned asymmetric synthesis procedure to the preparation of enantiopure derivatives of some commonly used polypyridylic ligands has...

Synthesis, spectral, thermal and antimicrobial studies on cobalt(II), nickel(II), copper(II), zinc(II) and palladium(II) complexes containing thiosemicarbazone ligand

Science.gov (United States)

El-Sawaf, Ayman K.; El-Essawy, Farag; Nassar, Amal A.; El-Samanody, El-Sayed A.

2018-04-01

The coordination characteristic of new N4-morpholinyl isatin-3-thiosemicarbazone (HL) towards Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) has been studies. The structures of the complexes were described by elemental analyses, molar conductivity, magnetic, thermal and spectral (IR, UV-Vis, 1H and 13C NMR and ESR) studies. On the basis of analytical and spectral studies the ligand behaves as monobasic tridentate ONS donor forming two five membered rings towards cobalt, copper and palladium and afforded complexes of the kind [M(L)X], (Mdbnd Co, Cu or Pd; Xdbnd Cl, Br or OAc). Whereas the ligand bound to NiCl2 as neutral tridentate ONS donor and with ZnCl2 as neutral bidentate NS donor. The newly synthesized thiosemicarbazone ligand and some of its complexes were examined for antimicrobial activity against 2 gram negative bacterial strains (Escherichia coli Pseudomonas and aeruginosa), 2 gram positive bacterial strains (Streptococcus pneumoniae and Staphylococcus aureus)} and two Pathogenic fungi (Aspergillus fumigatus and Candida albicans). All metal complexes possess higher antimicrobial activity comparing with the free thiosemicarbazone ligand. The high potent activities of the complexes may arise from the coordination and chelation, which tends to make metal complexes act as more controlling and potent antimicrobial agents, thus hindering the growing of the microorganisms. The antimicrobial results also show that copper bromide complex is better antimicrobial agent as compared to the Schiff base and its metal complexes.

Thermodynamic study on the complexation of Trivalent actinide and lanthanide cation by N-donor ligands in homogeneous conditions; Etude thermodynamique de la complexation des ions actinide (III) et lanthanide (III) par des ligands polyazotes en milieu homogene

Energy Technology Data Exchange (ETDEWEB)

Miguirditchian, M

2004-07-01

Polydentate N-donor ligands, alone or combined with a synergic acid, may selectively extract minor actinides(III) from lanthanide(III) ions, allowing to develop separation processes of long-live radioelements. The aim of the researches carried out during this thesis was to better understand the chemical mechanisms of the complexation of f-elements by Adptz, a tridentate N-donor ligand, in homogeneous conditions. A thermodynamic approach was retained in order to estimate, from an energetic point of view, the influence of the different contributions to the reaction, and to acquire a complete set of thermodynamic data on this reaction. First, the influence of the nature of the cation on the thermodynamics was considered. The stability constants of the 1/1 complexes were systematically determined by UV-visible spectrophotometry for every lanthanide ion (except promethium) and for yttrium in a mixed solvent methanol/water in volume proportions 75/25%. The thermodynamic parameters ({delta}H{sup 0} {delta}{sup S}) of complexation were estimated by the van't Hoff method and by micro-calorimetry. The trends of the variations across the lanthanide series are compared with similar studies. The same methods were applied to the study of three actinide(III) cations: plutonium, americium and curium. The comparison of these values with those obtained for the lanthanides highlights the increase of stability of these complexes by a factor of 20 in favor of the actinide cations. This gap is explained by a more exothermic reaction and is associated, in the data interpretation, to a higher covalency of the actinide(III)-nitrogen bond. Then, the influence of the change of solvent composition on the thermodynamic of complexation was studied. The thermodynamic parameters of the complexation of europium(III) by Adptz were determined for several fractions of methanol. The stability of the complex formed increases with the percentage of methanol in the mixed solvent, owing to an

Studies on complexation of a tridentate ONS Schiff base with lighter and heavier metals ions, and investigation into their biological properties

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Ali, A.M.; Juan, W.D.; Crouse, K.A.; Silong, S.

1999-05-01

Several new complexes of a tridentate ONS Schiff base derived from the condensation of S-benzyldithiocarbazate with salicylaldehyde have been characterised by elemental analyses, molar conductivity measurements, infrared, and electronic spectral studies. The tridentate Schiff base (HONSH) behaves as a dinegatively charged ligand coordinating through the thiolo sulphur, the azomethine nitrogen atom and the hydroxyl oxygen atom. It forms mono-ligand complexes of the general formula, [M(ONS)X], [M = Ni(II), Cu(II), Cr(III), Sb(III), Zn(II), Zr(IV) or U(VI) and X = H 2 O, Cl]. The ligand produced bis-chelated complex with Th(IV) of composition, [Th(ONS) 2 ]. Square-planar structures were proposed for the Ni(II) and Cu(II) complexes. Antimicrobial tests indicated that the Schiff base and five of the metal complexes of Cu(II), Ni(II), U(VI), Zn(II) and Sb(III) were found to be strongly active against bacteria. Ni(II) and Sb(III) complexes were the most effective against Pseudomonas aeruginosa (gram negative) while the Cu(II) complex proved to be the best against Bacillus cereus (gram positive bacteria). Antifungal activities were also noted with the Schiff base and the U(VI) complex. These compounds have shown results against Candida albicans fungi. But none of these compounds were effective against Aspergillus ochraceous fungi. (author)

Entangled zinc-ditetrazolate frameworks involving in situ ligand synthesis and topological modulation by various secondary N-donor ligands

International Nuclear Information System (INIS)

Li Yunwu; Chen Weilin; Wang Yonghui; Li Yangguang; Wang Enbo

2009-01-01

The introduction of various secondary N-donor ligands into an in situ ditetrazolate-ligand synthesis system of terephthalonitrile, NaN 3 and ZnCl 2 led to the formation of three new entangled frameworks Zn(pdtz)(4,4'-bipy).3H 2 O (1), [Zn(pdtz)(bpp)] 2 .3H 2 O (2) and Zn(pdtz) 0.5 (N 3 )(2,2'-bipy) (3) (4,4'-bipy=4,4'-bipyridine; bpp=1,3-bis(4-pyridyl)propane; 2,2'-bipy=2,2'-bipyridine; H 2 pdtz=5,5'-1,4-phenylene-ditetrazole). The formation of pdtz 2- ligand involves the Sharpless [2+3] cycloaddition reaction between terephthalonitrile and NaN 3 in the presence of Zn 2+ ion as a Lewis-acid catalyst under hydrothermal conditions. Compound 1 exhibits a fivefold interpenetrating 3D framework based on the diamondoid topology. Compound 2 displays a twofold parallel interpenetrating framework based on the wavelike individual network. Compound 3 possesses a 2D puckered network. These new Zn-ditetrazolate frameworks are highly dependent on the modulation of different secondary N-donor ligands. Their luminescent properties were investigated. - Graphical abstract: Three new entangled frameworks were prepared by an in situ ditetrazolate-ligand synthesis system assisted with various auxiliary N-donor ligands. The entangled structures can be modulated by different secondary ligands.

Trident Web page

Energy Technology Data Exchange (ETDEWEB)

Johnson, Randall P. [Los Alamos National Laboratory; Fernandez, Juan C. [Los Alamos National Laboratory

2012-06-25

An Extensive Diagnostic Suite Enables Cutting-edge Research at Trident The Trident Laser Facility at Los Alamos National Laboratory is an extremely versatile Nd:glass laser system dedicated to high energy density physics research and fundamental laser-matter interactions. Trident's Unique Laser Capabilities Provide an Ideal Platform for Many Experiments. The laser system consists of three high energy beams which can be delivered into two independent target experimental areas. The target areas are equipped with an extensive suite of diagnostics for research in ultra-intense laser matter interactions, dynamic material properties, and laser-plasma instabilities. Several important discoveries and first observations have been made at Trident including laser-accelerated MeV mono-energetic ions, nonlinear kinetic plasma waves, transition between kinetic and fluid nonlinear behavior, as well as other fundamental laser-matter interaction processes. Trident's unique long-pulse capabilities have enabled state-of-the-art innovations in laser-launched flyer-plates, and other unique loading techniques for material dynamics research.

Application of X-ray single crystal diffractometry to investigation of Np(5) complexes with n-donor ligands

International Nuclear Information System (INIS)

Andreev, G.

2007-01-01

Full text of publication follows. We present here some results of application of conventional X-ray single crystal diffractometry to the research on the interaction of Np(V) with N-donor ligands. Compounds that can coordinate to actinides through one or several nitrogen atoms are of a great variety and occur widely in the biosphere. For example, imidazole, pyridine and their derivatives are the building blocks of many biologically important molecules; triazines are known to occur in some aquatic plants. The presence of anthropogenic organic agents like amine-N-carboxylic acids in surface waters has the potential to re-mobilize metals from sediments and aquifers and to influence their bioavailability. The interaction of radionuclides with such ligands needs to be studied in detail to give fundamental understanding the conditions of the incorporation of long lived a-emitters (Np and Pu primarily) into the food chain. Another aspect of the same problem is the design of new chelating ligands for selective co-ordination of actinide ions as an alternative to the traditional sequestering agents. The problem of the separation of long-lived minor actinides and their transmutation also calls for design of new highly selective ligands for solvent extraction. Polydentate N-donor ligands are now considered to be very promising. A detailed study of structural chemistry is crucial for understanding the relationship between the architecture of the ligands and their binding affinity for actinides. The X-ray single crystal diffractometry became conventional technique as applied to the investigation of actinides in spite of difficulties regarding safe handling of radionuclides. This technique provides unambiguous information about modes of the ligand co-ordination to the metal ion and geometrical parameters of complexes. Moreover, the employment of a synchrotron radiation shows considerable promise for determination of solid state structures as well as obtaining structural

Studies on coordination chemistry and bioactivity of metal complexes of some nitrogen-sulfur donor ligands: Section A: hydraziniumdithiocarbazate and its complexes. Section B: complexes of Ni2+ and Cu2+ ions with s-picolyldithiocarbazate

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Liza bt Abdullah; Crouse, Karen A.; Ali, A.M.

2003-08-01

Two new nitrogen - sulphur donor ligands, hydraziniumdithiocarbazate(HzDTC) and S-picolyldithiocarbazate(SPDTC), along with three novel Schiff bases were prepared. Complexes of some of HzDTC with nickel(II), zinc(II), and those of SPDTC with nickel(II) and copper(II) were prepared and characterized by a variety of physico- chemical techniques. The ligand, HzDTC, was a potential bidentate and uninegatively charged providing terminal amino and thiolate bindings with the metal ions, while SPDTC coordinates via the pyridine nitrogen and the thiolate anion. All of the compounds were tested against four pathogenic bacteria and fungi. HzDTC was found to be very effective antimicrobial than its complexes. The complexes of SPDTC and the Schiff bases of HzDTC were more antifungal. None of the compounds were effective anti- cancer agents except for [Ni(HzDTCA)Cl.H 2 O], which was moderately active against CEM- SS (Human cell T- lymphoblastic) leukemic cells. (author)

Complexation of f elements by tripodal ligands containing aromatic nitrogens. Application to the selective extraction of actinides(III)

International Nuclear Information System (INIS)

Wietzke, Raphael

1999-01-01

This work initiates a research project, whose aim is the actinides(lll)/lanthanides(III) separation by liquid-liquid extraction. We were interested in the study of the coordination chemistry of lanthanides(III) and uranium(III) (uranium(III) as model for the actinides(III)), with the aim to show differences between the two families and to better understand the coordination properties involved in the extraction process. We studied the lanthanide(III) and uranium(III) complexation with tripodal ligands containing aromatic nitrogens. Several tripodal ligands were synthesized varying the type and the number of the donor atoms. The lanthanide(III) complexes have been characterized in the solid state and in solution (by several techniques: "1H NMR, ESMS, luminescence, UV spectrophotometry, conductometry). Differences in the coordination were found depending on the nature of the donor atoms. The new ligands, tris(2-pyrazinylmethyl)amine (tpza) et tris(N,N-diethyl-2-carbamoyl-6- pyridylmethyl)amine (tpaa), have shown a selectivity for the actinides(III) with promising results in liquid-liquid extraction. The comparison between the lanthanum(III) and uranium(III) complexes with the ligand tpza showed differences in the bonding nature, which could be attributed to a covalent contribution to the metal-ligand bond. (author) [fr

Lanthanide and actinide complexation studies with tetradentate 'N' donor ligands

International Nuclear Information System (INIS)

Bhattacharyya, A.; Mohapatra, M.; Mohapatra, P.K.; Rawat, N.; Tomar, B.S.; Gadly, T.; Ghosh, S.K.; Manna, D.; Ghanty, T.K.

2014-01-01

Because of their similar charge and chemical behaviour separation of trivalent actinides and lanthanides is an important and challenging task in nuclear fuel cycle. Soft (S,N) donor ligands show selectivity towards the trivalent actinides over the lanthanides. Out of various 'N' donor ligands studied, bis(1,2,4)triazinyl bipyridine (BTBP) and bis(1,2,4)triazinyl phenanthroline (BTPhen) were found to be most promising. In order to understand the separation behaviour of these ligands, their complexation studies with these 'f' block elements are essential. In the present work, complexation studies of various lanthanide ions (La 3+ , Eu 3+ and Er 3+ ) was studied with ethyl derivatives of BTBP (C 2 BTBP) and BTBPhen (C 2 BTPhen) and pentyl derivative of BTBP (C 5 BTBP) in acetonitrile medium using UV-Vis spectrophotometry, fluorescence spectroscopy and solution calorimetry. Computational studies were also carried out to understand the experimental results

Spectroscopic investigation of complexation of Cm(III) und Eu(III) with partitioning-relevant N-donor ligands

International Nuclear Information System (INIS)

Bremer, Antje

2014-01-01

The separation of trivalent actinides and lanthanides is an essential part of the development of improved nuclear fuel cycles. Liquid-liquid extraction is an applicable technique to achieve this separation. Due to the chemical similarity and the almost identical ionic radii of trivalent actinides and lanthanides this separation is, however, only feasible with highly selective extracting agents. It has been proven that molecules with soft sulphur or nitrogen donor atoms have a higher affinity for trivalent actinides. In the present work, the complexation of Cm(III) and Eu(III) with N-donor ligands relevant for partitioning has been studied by time-resolved laser fluorescence spectroscopy (TRLFS). This work aims at a better understanding of the molecular reason of the selectivity of these ligands. In this context, enormous effort has been and is still put into detailed investigations on BTP and BTBP ligands, which are the most successful N-donor ligands for the selective extraction of trivalent actinides, to date. Additionally, the complexation and extraction behavior of molecules which are structurally related to these ligands is studied. The ligand C5-BPP (2,6-bis(5-(2,2-dimethylpropyl)-1H-pyrazol-3-yl)pyridine) where the triazine rings of the aromatic backbone of the BTP ligands have been replaced by pyrazole rings is one of these molecules. Laser fluorescence spectroscopic investigation of the complexation of Cm(III) with this ligand revealed stepwise formation of three (Cm(C5-BPP) n ) 3+ complexes (n = 1 - 3). The stability constant of the 1:3 complex was determined (log β 3 = 14.8 ± 0.4). Extraction experiments have shown that, in contrast to BTP and BTBP ligands, C5-BPP needs an additional lipophilic anion source such as a 2-bromocarboxylic acid to selectively extract trivalent actinides from nitric acid solutions. The comparison of the stability constant of the (Cm(C5-BPP) 3 ) 3+ complex with the stability constant of the (Cm(nPr-BTP) 3 ) 3+ complex

Solid-state thermolysis of a fac-rhenium(I) carbonyl complex with a redox non-innocent pincer ligand.

Science.gov (United States)

Jurca, Titel; Chen, Wen-Ching; Michel, Sheila; Korobkov, Ilia; Ong, Tiow-Gan; Richeson, Darrin S

2013-03-25

The development of rhenium(I) chemistry has been restricted by the limited structural and electronic variability of the common pseudo-octahedral products fac-[ReX(CO)3L2] (L2 = α-diimine). We address this constraint by first preparing the bidentate bis(imino)pyridine complexes [(2,6-{2,6-Me2C6H3N=CPh}2C5H3N)Re(CO)3X] (X = Cl 2, Br 3), which were characterized by spectroscopic and X-ray crystallographic means, and then converting these species into tridentate pincer ligand compounds, [(2,6-{2,6-Me2C6H3N=CPh}2C5H3N)Re(CO)2X] (X = Cl 4, Br 5). This transformation was performed in the solid-state by controlled heating of 2 or 3 above 200 °C in a tube furnace under a flow of nitrogen gas, giving excellent yields (≥95 %). Compounds 4 and 5 define a new coordination environment for rhenium(I) carbonyl chemistry where the metal center is supported by a planar, tridentate pincer-coordinated bis(imino)pyridine ligand. The basic photophysical features of these compounds show significant elaboration in both number and intensity of the d-π* transitions observed in the UV/Vis spec tra relative to the bidentate starting materials, and these spectra were analyzed using time-dependent DFT computations. The redox nature of the bis(imino)pyridine ligand in compounds 2 and 4 was examined by electrochemical analysis, which showed two ligand reduction events and demonstrated that the ligand reduction shifts to a more positive potential when going from bidentate 2 to tridentate 4 (+160 mV for the first reduction step and +90 mV for the second). These observations indicate an increase in electrostatic stabilization of the reduced ligand in the tridentate conformation. Elaboration on this synthetic methodology documented its generality through the preparation of the pseudo-octahedral rhenium(I) triflate complex [(2,6-{2,6-Me2C6H3N=CPh}2C5H3N)Re(CO)2OTf] (7, 93 % yield). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nickel(II) and palladium(II) triphenylphosphine complexes incorporating tridentate Schiff base ligands: Synthesis, characterization and biocidal activities

Science.gov (United States)

Shabbir, Muhammad; Akhter, Zareen; Ashraf, Ahmad Raza; Ismail, Hammad; Habib, Anum; Mirza, Bushra

2017-12-01

Nickel(II) and palladium(II) triphenylphosphine complexes incorporating tridentate Schiff bases have been prepared and characterized by elemental analysis as well as by spectroscopic techniques (FTIR & NMR). The synthesized compounds were assessed to check their potential biocidal activity by using different biological assays (brine shrimp cytotoxicity, antimicrobial, antioxidant, antitumor and drug-DNA interaction). Results of brine shrimp cytotoxicity assay showed that ligand molecules are more bioactive than metal complexes with LD50 as low as 12.4 μg/mL. The prominent antitumor activity was shown by nickel complexes while the palladium complexes exhibited moderate activity. The synthesized compounds have shown high propensity for DNA binding either through intercalation or groove binding which represents the mechanism of antitumor effect of these compounds. Additionally, ligand molecules and nickel metal complexes showed significant antioxidant activity with IC50 values as low as 3.1 μg/mL and 18.9 μg/mL respectively while palladium complexes exhibited moderate activity. Moreover, in antimicrobial assays H2L1, Ni(L1)PPh3 and H2L3 showed dual inhibition against bacterial and fungal strains while for the rest of the compounds varying degree of activity was recorded against different strains. Overall comparison of results suggests that the synthesized compounds can be promising candidate for drug formulation and development.

Specific ability of sulfur-ligands on removal of 203Hg-labeled organomercury from hemoglobin in comparison with nitrogen-ligands

International Nuclear Information System (INIS)

Hojo, Yasuji; Sugiura, Yukio; Tanaka, Hisashi

1975-01-01

Removal of 203 Hg-labeled organomercurials, bound to sulfhydryl groups of hemoglobin, by various chelating agents was investigated by the use of equilibrium dialysis. Organomercurials employed were chlormerodrin, methylmercury, ethylmercury and phenylmercury compounds. Higher and more specific effects of the sulfur-ligands, such as penicillamine and glutathione, on removal of organomercurial were found as compared with those of the nitrogen-ligands such as EDTA, glycine and polymethylenediamines. Linear correlation was observed between the degree of organomercury elimination from hemoglobin and the stability constant (log K 1 ) of 1:1 organomercury complex in both the sulfur- and nitrogen-ligand systems and at the same value of log K 1 , the elimination-effect of sulfur-ligands was extremely greater than that of the nitrogen-ligands. The relationship between the average percentage of removal and the Taft's polar substituent constant of organic moiety of the metal was also linear among the organomercury compounds other than chlormerodrin. The average removal percentage by sulfur-ligands increased in the order, ethylmercury>methylmercury>phenylmercury, while that of the nitrogen-ligands was not different among the organomercurials investigated. In addition, direct ligand-exchange reaction between hemoglobin-SH and the ligand coordinating-atom (S or N) against organomercurials rather than Ssub(N2) reaction via the ternary complex, hemoglobin-S-RHg-ligand, is postulated. (auth.)

Zr (IV COMPLEXES OF SOME NITROGEN-OXYGEN DONOR LIGANDS (SEMICARBAZONES & SALICYLALDAZINE

Directory of Open Access Journals (Sweden)

Z F DAWOOD

2002-06-01

Full Text Available Complexes containing mixed ligands of zirconium (IV have been synthesized by the reaction of zirconium (IV nitrate (Zr(NO34, 5H2O with salicylaldazine (SAH2 and semicarbazone ligands benzaldehyde semicarbazone (BSCH, 4-methoxybenzaldehyde semicarbzone (MBSCH, 2-chlorobenzaldehyde semicrbazone (CISCH and cinnamaldehyde semicarbazone (CinSCH forming complexes of the type [Zr2(SAH2(SCH2](NO38 and [Zr2(SA2 (SC2](NO32 in neutral and basic medium respectively. The ligands and their complexes are characterized physico-chemically.

The role of nitrogen in the formation of oxygen-related thermal donors in silicon

International Nuclear Information System (INIS)

Griffin, J.A.; Hartung, J.; Weber, J.

1989-01-01

Nitrogen doped silicon is investigated by Photothermal Ionisation Spectroscopy (PTIS) and Infrared Absorption (IR). The Shallow Thermal Donors (STD) are observed in this nitrogen doped Cz-silicon as well as the deeper Thermal Donors (TD). The Thermal Donor Growth in nitrogen doped material is reduced in comparison to nominally undoped oxygen-rich silicon. The half-widths of the spectral lines arising from the STD-transitions are observed to be dependent on the nitrogen concentration. The results suggest only a catalytic role of N in the STD-growth. (author) 13 refs., 3 figs., 1 tab

Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

Science.gov (United States)

Ejidike, Ikechukwu P.; Ajibade, Peter A.

2016-01-01

The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

Ruthenium(III Complexes of Heterocyclic Tridentate (ONN Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

Directory of Open Access Journals (Sweden)

Ikechukwu P. Ejidike

2016-01-01

Full Text Available The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(LCl2(H2O] (where L = tridentate NNO ligands. The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS radicals, with DPPH scavenging capability in the order: [(PAEBODRuCl2] > [(BZEBODRuCl2] > [(MOABODRuCl2] > [Vit. C] > [rutin] > [(METBODRuCl2], and ABTS radical in the order: [(PAEBODRuCl2] < [(MOABODRuCl2] < [(BZEBODRuCl2] < [(METBODRuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10, melanoma cancer cell (UACC-62 and breast cancer cell (MCF-7 by SRB assay.

Syntheses, Magnetic and Spectral Studies on the Coordination Compounds of the Polystyrene-anchored Thiazolidin-4-one

Directory of Open Access Journals (Sweden)

Dinesh Kumar

2012-01-01

Full Text Available The reaction between polystyrene 3-formylsalicylate and thiophene-2-carboxylic acid hydrazide in DMF in the presence of ethyl acetate results in the formation of polystyrene N-(2-carbamoylthienyl-3'-carboxy-2'-hydroxybenzylideneimine (I. A benzene suspension of I reacts with mercaptoacetic acid and forms the polystyrene N-(2-carbamoylthienyl-C-(3'-carboxy-2'-hydroxyphenyl thiazolidin-4-one, PSCH2–LH2 (II. A DMF suspension of II reacts with Zn(II, Co(II, Cu(II, Zr(OH2(IV and MoO2(VI ions and forms the corresponding polystyrene-anchored coordination compounds, [PSCH2–LZn(DMF] (III, [PSCH2–LCo(DMF3] (IV, [PSCH2–LHCu(OAc] (V, [PSCH2–LH2Zr(OH2(OAc2] (VI and [PSCH2–LHMoO2(acac] (VII respectively. The polystyrene-anchored coordination compounds have been characterized on the basis of elemental analyses, spectral (IR, reflectance, ESR studies and magnetic susceptibility measurements. II acts as a neutral tridentate ONS donor ligand in VI, a monobasic bidentate OS donor ligand in VII, a monobasic tridentate ONS donor ligand in V and a dibasic tridentate ONO donor ligand in III and IV. The acetato groups behave as monodentate ligands in V and VI. A square-planar structure for V, a tetrahedral structure for III, an octahedral structure for IV and VII and a pentagonal-bipyramidal structure for VI are suggested.

Synthesis and structures of a pincer-type rhodium(iii) complex: reactivity toward biomolecules.

Science.gov (United States)

Milutinović, Milan M; Bogojeski, Jovana V; Klisurić, Olivera; Scheurer, Andreas; Elmroth, Sofi K C; Bugarčić, Živadin D

2016-10-04

A novel rhodium(iii) complex [Rh III (H 2 L tBu )Cl 3 ] (1) (H 2 L tBu = 2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine) containing a pincer type, tridentate nitrogen-donor chelate system was synthesized. Single crystal X-ray structure analysis revealed that 1 crystallizes in the orthorhombic space group Pbcn with a = 20.7982(6), b = 10.8952(4), c = 10.9832(4) Å, V = 2488.80(15) Å 3 , and eight molecules in the unit cell. The rhodium center in the complex [Rh III (H 2 L tBu )Cl 3 ] (1) is coordinated in a slightly distorted octahedral geometry by the tridentate N,N,N-donor and three chloro ligands, adopting a mer arrangement with an essentially planar ligand skeleton. Due to the tridentate coordination of the N,N,N-donor, the central nitrogen atom N1 is located closer to the Rh III center. The reactivity of the synthesized complex toward small biomolecules (l-methionine (l-Met), guanosine-5'-monophosphate (5'-GMP), l-histidine (l-His) and glutathione (GSH)) and to a series of duplex DNAs and RNA was investigated. The order of reactivity of the studied small biomolecules is: 5'-GMP > GSH > l-Met > l-His. Duplex RNA reacts faster with the [Rh III (H 2 L tBu )Cl 3 ] complex than duplex DNA, while shorter duplex DNA (15mer GG) reacts faster compared with 22mer GG duplex DNA. In addition, a higher reactivity is achieved with a DNA duplex with a centrally located GG-sequence than with a 22GTG duplex DNA, in which the GG-sequence is separated by a T base. Furthermore, the interaction of this metal complex 1 with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) was examined by absorption (UV-Vis) and emission spectral studies (EthBr displacement studies). Overall, the studied complex exhibited good DNA and BSA interaction ability.

Synthesis and evaluation of ligands with mixed amide and phosphonate, phosphinoxide, and phosphonothioate sites for An(III)/Ln(III) extraction

NARCIS (Netherlands)

Iqbal, M.; Struijk, R.G.; Huskens, Jurriaan; Sypula, M.; Wilden, A.; Modolo, G.; Verboom, Willem

2012-01-01

Various organophosphorus ligands with a combination of different donor sites were synthesized and evaluated by solvent extraction studies for the complexation of Am(III)/Eu(III). Among the ligands with a glycolamide backbone, those with mixed amide and PO donor sites and a central oxygen or nitrogen

Binuclear complexes of technetium. Evidence for bis(terdentate)bidentate coordination by the bridging ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine to technetium(V)

International Nuclear Information System (INIS)

Du Preez, J.G.H.; Gerber, T.I.A.; Gibson, M.L.; Geyser, R.

1990-01-01

The authors have used the potentially bis(terdentate) nitrogen aromatic heterocyclic ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz) to prepare mono- and bimetallic technetium(V) complexes bound to tppz. The stimulus for the development of the coordination chemistry of the man-made element technetium is provided by the use of complexes of this element as anatomical imaging agents in nuclear medicine. Although the chemistry of technetium(V) with nitrogen donor ligands is well understood, no complexes have been prepared using potentially terdentate neutral nitrogen donor ligands of this metal in the +5 oxidation state

Complexes of groups 3,4, the lanthanides and the actinides containing neutral phophorus donor ligands

International Nuclear Information System (INIS)

Fryzuk, M.D.; Haddad, T.S.; Berg, D.J.

1990-01-01

Of relevance to this review are complexes of the early transition elements, in particular groups 3 and 4 and the lanthanides and actinides. In this review the authors have attempted to collect all the data up to the end of 1988 for complexed of groups 3 and 4, the lanthanides and the actinides that contain phosphorus donor ligands. The 1989s have seen a renaissance of the use of phosphine donors for the early d elements (groups 3 and 4) and the f elements. Neutral phosphorus donors are defined as primary (PH 2 R), secondary (PH 2 ) or tertiary phosphines (PR 3 ), including complexes of phosphine, PH 3 . Also reviewed are complexes of PF 3 and phosphites, P(OR) 3 . Specifically excluded are phosphido derivates, PR 2 . The ability of a neutral phosphorus donor to bind the metals of groups 3 and 4, the lanthanides and the actinides is now well established. While there are still no examples of lanthanum or actinium phosphine complexes, such derivatives should be accessible at least for lanthanum. series. However, there is no obvious chemical reason to suggest that such derivatives cannot be generated. The phosphine ligands that appear to generate the most stable phosphine-metal interaction are chelating phosphines such as dmpe, trmpe and trimpsi. In addition, the use of the chelate effect in conjunction with a hard ligand such as the amide in - N(SiMe 2 CH 2 PMe 2 ) 2 , or an alkoxide as found in - OC(BU t ) 2 CH 2 PMe 2 , also appears to be effective in anchoring the phosphine donor to the metal. The majority of low oxidation state derivatives of the group 4 elements are stabilized by phosphine donors in contrast with other parts of the transition series where one finds that classic π-acceptor-type ligands such as CO or RNC are utilized. 233 refs

Accomplishments in the Trident Laser Facility

Energy Technology Data Exchange (ETDEWEB)

Fernandez, Juan Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-08-25

Trident has been an extremely productive laser facility, despite its modest size and operating cost in the firmament of high-energy, high-power laser facilities worldwide. More than 150 peer-reviewed journal articles (in 39 different journals) have been published using Trident experimental data, many in high-impact journals such as Nature, Nature Physics, Nature Communications, and Physical Review Letters. More than 230 oral presentations involving research at Trident have been presented at national and international conferences. Trident publications have over 5000 citations in the literature with an h-index of 38. AT least 23 Los Alamos postdoctoral researchers have worked on Trident. In the period since its inception in 1992-2007, despite not issuing formal proposal calls for access nor functioning explicitly as a user facility until later, Trident has 170 unique users from more than 30 unique institutions, such as Los Alamos, Lawrence Livermore, and Sandia national laboratories, various University of California campuses, General Atomic, Imperial College, and Ecole Polytechnique. To reinforce its role as an important Los Alamos point of connection to the external research community, at least 20 PhD students did a significant fraction of their thesis work on Trident. Such PhD students include Mike Dunne (Imperial College, 1995) - now director of LCLS and professor at Stanford; David Hoarty (IC, 1997) - scientist at Atomic Weapons Establishment, UK; Dustin Froula (UC Davis, 2002) - Plasma and Ultrafast Physics Group leader at the Laboratory for Laser Energetics and assistant professor at the Physics and Astronomy Department at the University of Rochester; Tom Tierney (UC Irvine, 2002) - scientist at Los Alamos; Eric Loomis (Arizona State U., 2005) - scientist at Los Alamos; and Eliseo Gamboa (University of Michigan, 2013) - scientist at the Linac Coherent Light Source. The work performed on Trident, besides its scientific impact, has also supported the Inertial

Colorimetric detection of hydrogen peroxide by dioxido-vanadium(V) complex containing hydrazone ligand: synthesis and crystal structure

Science.gov (United States)

Kurbah, Sunshine D.; Syiemlieh, Ibanphylla; Lal, Ram A.

2018-03-01

Dioxido-vanadium(V) complex has been synthesized in good yield, the complex was characterized by IR, UV-visible and 1H NMR spectroscopy. Single crystal X-ray crystallography techniques were used to assign the structure of the complex. Complex crystallized with monoclinic P21/c space group with cell parameters a (Å) = 39.516(5), b (Å) = 6.2571(11), c (Å) = 17.424(2), α (°) = 90, β (°) = 102.668(12) and γ (°) = 90. The hydrazone ligand is coordinate to metal ion in tridentate fashion through -ONO- donor atoms forming a distorted square pyramidal geometry around the metal ion.

Studies on coordination chemistry and bioactivity of complexes of a tridentate ONS Schiff base with some heavier transition metal ions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Tan Mei Lin; Ali, A.M.

2003-09-01

A tridentate Schiff base, S-benzyl-β-N-(2-hydroxyphenyl)methylenedithiocarbazate, (HONSH), with a donor sequence of ONS, was synthesized from the condensation of S-benzyldithiocarbazate (SBDTC) with an equimolar amount of 2-hydroxybenzaldehyde in absolute ethanol. The reactions of HONSH with metal ions [La(III), Ce(IV) and Th(IV)] yielded complexes of compositions, [La(ONS)NO 3 .2H 2 O], [Ce(ONS)(NO 3 ) 2 ] and [Th(ONS) 2 ]. The ligands and the complexes were characterized from elemental analyses and spectroscopic measurements. The metal complexes were found to be active against colon cancer cell lines with the CD 50 values of 27.5, 28.4 and 19.3 μg/ml for the La(III), Ce(FV) and Th(IV) complexes, respectively. The La(IH) complex was found to be very active against leukemic cell lines with the CD 50 value of 6.8 μg/ml. (author)

A Protein Data Bank survey reveals shortening of intermolecular hydrogen bonds in ligand-protein complexes when a halogenated ligand is an H-bond donor.

Science.gov (United States)

Poznański, Jarosław; Poznańska, Anna; Shugar, David

2014-01-01

Halogen bonding in ligand-protein complexes is currently widely exploited, e.g. in drug design or supramolecular chemistry. But little attention has been directed to other effects that may result from replacement of a hydrogen by a strongly electronegative halogen. Analysis of almost 30000 hydrogen bonds between protein and ligand demonstrates that the length of a hydrogen bond depends on the type of donor-acceptor pair. Interestingly, lengths of hydrogen bonds between a protein and a halogenated ligand are visibly shorter than those estimated for the same family of proteins in complexes with non-halogenated ligands. Taking into account the effect of halogenation on hydrogen bonding is thus important when evaluating structural and/or energetic parameters of ligand-protein complexes. All these observations are consistent with the concept that halogenation increases the acidity of the proximal amino/imino/hydroxyl groups and thus makes them better, i.e. stronger, H-bond donors.

Charged dopants in neutral supercells through substitutional donor (acceptor): nitrogen donor charging of the nitrogen-vacancy center in diamond

Science.gov (United States)

Löfgren, Robin; Pawar, Ravinder; Öberg, Sven; Larsson, J. Andreas

2018-02-01

Charged defects are traditionally computed by adding (subtracting) electrons for negative (positive) impurities. When using periodic boundary conditions this results in artificially charged supercells that also require a compensating background charge of the opposite sign, which makes slab supercells problematic because of an arbitrary dependence on the vacuum thickness. In this work, we test the method of using neutral supercells through the use of a substitutional electron donor (acceptor) to describe charged systems. We use density functional theory (DFT) to compare the effects of charging the well-studied NV-center in diamond by a substitutional donor nitrogen. We investigate the influence of the donor-N on the NV-center properties as a function of the distance between them, and find that they converge toward those obtained when adding an electron. We analyze the spin density and conclude that the donor-N has a zero magnetic moment, and thus, will not be seen in electron spin resonance. We validate our DFT energies through comparison to GW simulations. Charging the NV-center with a substitutional donor-N enables accurate calculations of slabs, without the ambiguity of using charged supercells. Implantation of donor-N atoms opens up the possibility to engineer NV-centers with the desired charge state for future ICT and sensor applications.

A Protein Data Bank survey reveals shortening of intermolecular hydrogen bonds in ligand-protein complexes when a halogenated ligand is an H-bond donor.

Directory of Open Access Journals (Sweden)

Jarosław Poznański

Full Text Available Halogen bonding in ligand-protein complexes is currently widely exploited, e.g. in drug design or supramolecular chemistry. But little attention has been directed to other effects that may result from replacement of a hydrogen by a strongly electronegative halogen. Analysis of almost 30000 hydrogen bonds between protein and ligand demonstrates that the length of a hydrogen bond depends on the type of donor-acceptor pair. Interestingly, lengths of hydrogen bonds between a protein and a halogenated ligand are visibly shorter than those estimated for the same family of proteins in complexes with non-halogenated ligands. Taking into account the effect of halogenation on hydrogen bonding is thus important when evaluating structural and/or energetic parameters of ligand-protein complexes. All these observations are consistent with the concept that halogenation increases the acidity of the proximal amino/imino/hydroxyl groups and thus makes them better, i.e. stronger, H-bond donors.

Protein-ligand interfaces are polarized: discovery of a strong trend for intermolecular hydrogen bonds to favor donors on the protein side with implications for predicting and designing ligand complexes.

Science.gov (United States)

Raschka, Sebastian; Wolf, Alex J; Bemister-Buffington, Joseph; Kuhn, Leslie A

2018-04-01

Understanding how proteins encode ligand specificity is fascinating and similar in importance to deciphering the genetic code. For protein-ligand recognition, the combination of an almost infinite variety of interfacial shapes and patterns of chemical groups makes the problem especially challenging. Here we analyze data across non-homologous proteins in complex with small biological ligands to address observations made in our inhibitor discovery projects: that proteins favor donating H-bonds to ligands and avoid using groups with both H-bond donor and acceptor capacity. The resulting clear and significant chemical group matching preferences elucidate the code for protein-native ligand binding, similar to the dominant patterns found in nucleic acid base-pairing. On average, 90% of the keto and carboxylate oxygens occurring in the biological ligands formed direct H-bonds to the protein. A two-fold preference was found for protein atoms to act as H-bond donors and ligand atoms to act as acceptors, and 76% of all intermolecular H-bonds involved an amine donor. Together, the tight chemical and geometric constraints associated with satisfying donor groups generate a hydrogen-bonding lock that can be matched only by ligands bearing the right acceptor-rich key. Measuring an index of H-bond preference based on the observed chemical trends proved sufficient to predict other protein-ligand complexes and can be used to guide molecular design. The resulting Hbind and Protein Recognition Index software packages are being made available for rigorously defining intermolecular H-bonds and measuring the extent to which H-bonding patterns in a given complex match the preference key.

Protein-ligand interfaces are polarized: discovery of a strong trend for intermolecular hydrogen bonds to favor donors on the protein side with implications for predicting and designing ligand complexes

Science.gov (United States)

Raschka, Sebastian; Wolf, Alex J.; Bemister-Buffington, Joseph; Kuhn, Leslie A.

2018-02-01

Understanding how proteins encode ligand specificity is fascinating and similar in importance to deciphering the genetic code. For protein-ligand recognition, the combination of an almost infinite variety of interfacial shapes and patterns of chemical groups makes the problem especially challenging. Here we analyze data across non-homologous proteins in complex with small biological ligands to address observations made in our inhibitor discovery projects: that proteins favor donating H-bonds to ligands and avoid using groups with both H-bond donor and acceptor capacity. The resulting clear and significant chemical group matching preferences elucidate the code for protein-native ligand binding, similar to the dominant patterns found in nucleic acid base-pairing. On average, 90% of the keto and carboxylate oxygens occurring in the biological ligands formed direct H-bonds to the protein. A two-fold preference was found for protein atoms to act as H-bond donors and ligand atoms to act as acceptors, and 76% of all intermolecular H-bonds involved an amine donor. Together, the tight chemical and geometric constraints associated with satisfying donor groups generate a hydrogen-bonding lock that can be matched only by ligands bearing the right acceptor-rich key. Measuring an index of H-bond preference based on the observed chemical trends proved sufficient to predict other protein-ligand complexes and can be used to guide molecular design. The resulting Hbind and Protein Recognition Index software packages are being made available for rigorously defining intermolecular H-bonds and measuring the extent to which H-bonding patterns in a given complex match the preference key.

Preparation, spectral, X-ray powder diffraction and computational studies and genotoxic properties of new azo-azomethine metal chelates

Science.gov (United States)

Bitmez, Şirin; Sayin, Koray; Avar, Bariş; Köse, Muhammet; Kayraldız, Ahmet; Kurtoğlu, Mükerrem

2014-11-01

A new tridentate azo-azomethine ligand, N‧-[{2-hydroxy-5-[(4-nitrophenyl)diazenyl]phenyl}methylidene]benzohydrazidemonohydrate, (sbH·H2O) (1), is prepared by condensation of benzohydrazide and 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde (a) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in EtOH. The five coordination compounds, [Co(sb)2]·4H2O (2), [Ni(sb)2]·H2O (3), [Cu(sb)2]·4H2O (4), [Zn(sb)2]·H2O (5) and [Cd(sb)2]·H2O (6) are prepared by reacting the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with the ligand. The structures of the compounds are elucidated from the elemental analyses data and spectroscopic studies. It is found the ligand acts as a tridentate bending through phenolic and carbonyl oxygens and nitrogen atom of the Cdbnd Nsbnd group similar to the most of salicylaldimines. Comparison of the infrared spectra of the ligand and its metal complexes confirm that azo-Schiff base behaves as a monobasic tridentate ligand towards the central metal ion with an ONO donor sequence. Upon complexation with the ligand, the Cd(II), and Zn(II) ions form monoclinic structures, while Co(II), Cu(II) and Ni(II) ions form orthorhombic structures. Quantum chemical calculations are performed on tautomers and its metal chelates by using DFT/B3LYP method. Most stable tautomer is determined as tautomer (1a). The geometrical parameters of its metal chelates are obtained as theoretically. The NLO properties of tautomer (1a) and its metal complexes are investigated. Finally, the ligand and its metal complexes are assessed for their genotoxicity.

Anti-Inflammatory Oxicams as Multi-donor Ligand Systems: pH- and Solvent-Dependent Coordination Modes of Meloxicam and Piroxicam to Ru and Os.

Science.gov (United States)

Aman, Farhana; Hanif, Muhammad; Kubanik, Mario; Ashraf, Adnan; Söhnel, Tilo; Jamieson, Stephen M F; Siddiqui, Waseeq Ahmad; Hartinger, Christian G

2017-04-06

The nitrogen- and sulfur-containing 1,2-benzothiazines meloxicam and piroxicam are widely used as nonsteroidal anti-inflammatory drugs. Intrigued by the presence of multiple donor atoms and therefore potentially rich coordination chemistry, we prepared a series of organometallic Ru and Os compounds with meloxicam and piroxicam featuring either as mono- or bidentate ligand systems. The choice of the solvent and the pH value was identified as the critical parameter to achieve selectively mono- or bidentate coordination. The coordination modes were confirmed experimentally by NMR spectroscopy and single crystal X-ray diffraction analysis. Using DFT calculations, it was established that complexes in which meloxicam acts as a bidentate N,O donor are energetically more favorable than coordination as O,O and S,O donor systems. Since meloxicam and piroxicam derivatives have shown anticancer activity in the past, we aimed to compare the complexes with mono- and bidentate ligands on their in vitro anticancer activity. However, stability studies revealed that only the latter complexes were stable in [D 6 ]DMSO/D 2 O (5:95) and therefore no direct comparisons could be made. The meloxicam complexes 1 and 2 showed moderate cytotoxicity, whereas the piroxicam derivatives 5 and 6 were hardly active against the utilized cell lines. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, spectroscopic characterization, solid state d.c. electrical conductivity and biological studies of some lanthanide(III chloride complexes with a heterocyclic Schiff base ligand

Directory of Open Access Journals (Sweden)

K. Mohanan

2016-07-01

Full Text Available Condensation of 2-hydroxy-1-naphthaldehyde with 2-amino-3-carboxyethyl-4,5-dimethylthiophene in 1:1 molar ratio, yielded a potentially tridentate Schiff base viz. 2-[N-(2′-hydroxy-1-naphthylideneamino]-3-carboxyethyl-4,5-dimethylthiophene (HNAT. This ligand formed complexes with lanthanum(III, cerium(III, praseodymium(III, neodymium(III, samarium(III, europium(III and gadolinium(III chloride under well defined conditions. These complexes were characterized through elemental analysis, molar conductance, magnetic moment measurements, IR, UV–Vis, FAB mass and 1H NMR spectral studies. Analytical data showed that all the metal complexes exhibited 1:1 metal–ligand ratio. Molar conductance values adequately confirmed the non-electrolytic nature of the metal complexes. The proton NMR spectral observations supplement the IR spectral assignments. The spectral data revealed that the ligand acted as neutral tridentate, coordinating to the metal ion through azomethine nitrogen, ester carbonyl and naphtholate oxygen without deprotonation. The ligand and its lanthanum(III chloride complex were subjected to XRD studies. The lanthanum(III chloride complex has undergone a facile transesterification reaction. The solid state d.c. electrical conductivity of some selected complexes were measured as a function of temperature, indicating the semiconducting nature of the metal complexes. The antimicrobial activities were examined by disk diffusion method against some pathogenic bacterial and fungal species.

Activation of the Hg-C Bond of Methylmercury by [S2]-Donor Ligands.

Science.gov (United States)

Karri, Ramesh; Banerjee, Mainak; Chalana, Ashish; Jha, Kunal Kumar; Roy, Gouriprasanna

2017-10-16

Here we report that [S 2 ]-donor ligands Bmm OH , Bmm Me , and Bme Me bind rapidly and reversibly to the mercury centers of organomercurials, RHgX, and facilitate the cleavage of Hg-C bonds of RHgX to produce stable tetracoordinated Hg(II) complexes and R 2 Hg. Significantly, the rate of cleavage of Hg-C bonds depends critically on the X group of RHgX (X = BF 4 - , Cl - , I - ) and the [S 2 ]-donor ligands used to induce the Hg-C bonds. For instance, the initial rate of cleavage of the Hg-C bond of MeHgI induced by Bme Me is almost 2-fold higher than the initial rate obtained by Bmm OH or Bmm Me , indicating that the spacer between the two imidazole rings of [S 2 ]-donor ligands plays a significant role here in the cleavage of Hg-C bonds. Surprisingly, we noticed that the initial rate of cleavage of the Hg-C bond of MeHgI induced by Bme Me (or Bmm Me ) is almost 10-fold and 100-fold faster than the cleavage of Hg-C bonds of MeHgCl and [MeHg]BF 4 respectively, under identical reaction conditions, suggesting that the Hg-C bond of [MeHg]BF 4 is highly inert at room temperature (21 °C). We also show here that the nature of the final stable cleaved products, i.e. Hg(II) complexes, depends on the X group of RHgX and the [S 2 ]-donor ligands. For instance, the reaction of Bmm Me with MeHgCl (1:1 molar ratio) afforded the formation of the 16-membered metallacyclic dinuclear mercury compound (Bmm Me ) 2 Hg 2 Cl 4 , in which the two Cl atoms are located inside the ring, whereas due to the large size of the I atom, a similar reaction with MeHgI yielded polymeric [(Bmm Me ) 2 HgI 2 ] m ·(MeHgI) n . However, the treatment of Bmm Me with ionic [RHg]BF 4 led to the formation of the tetrathione-coordinated mononuclear mercury compound [(Bmm Me ) 2 Hg](BF 4 ) 2 , where BF 4 - serves as a counteranion.

Probing new charged scalars with neutrino trident production

Science.gov (United States)

Magill, Gabriel; Plestid, Ryan

2018-03-01

We investigate the possibility of using neutrino trident production to probe leptophilic charged scalars at future high intensity neutrino experiments. We show that under specific assumptions, this production process can provide competitive sensitivity for generic charged scalars as compared to common existing bounds. We also investigate how the recently proposed mixed-flavor production—where the two oppositely charged leptons in the final state need not be muon flavored—can give a 20%-50% increase in sensitivity for certain configurations of new physics couplings as compared to traditional trident modes. We then categorize all renormalizable leptophilic scalar extensions based on their representation under SU (2 )×U (1 ), and discuss the Higgs triplet and Zee-Babu models as explicit UV realizations. We find that the inclusion of additional doubly charged scalars and the need to reproduce neutrino masses make trident production uncompetitive with current bounds for these specific UV completions. Our work represents the first application of neutrino trident production to study charged scalars. Additionally, it is the first application of mixed-flavor trident production to study physics beyond the standard model more generally.

Diverse CdII coordination complexes derived from bromide isophthalic acid binding with auxiliary N-donor ligands

International Nuclear Information System (INIS)

Tang, Meng; Dong, Bao-Xia; Wu, Yi-Chen; Yang, Fang; Liu, Wen-Long; Teng, Yun-Lei

2016-01-01

The coordination characteristics of 4-bromoisophthalic acid (4-Br-H 2 ip) have been investigated in a series of Cd II -based frameworks. Hydrothermal reactions of Cd II salts and 4-Br-H 2 ip together with flexible or semiflexible N-donor auxiliary ligands resulted in the formation of four three-dimensional coordination complexes with diverse structures: (Cd(bix) 0.5 (bix) 0.5 (4-Br-ip)]·H 2 O) n (1), [Cd(bbi) 0.5 (bbi) 0.5 (4-Br-ip)] n (2), ([Cd(btx) 0.5 (4-Br-ip)(H 2 O)]·0.5CH 3 OH·H 2 O) n (3) and ([Cd(bbt) 0.5 (4-Br-ip)(H 2 O)]·3·5H 2 O) n (4). These compounds were characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction. They displayed diverse structures depending on the configuration of the 4-connected metal node, the coordination mode of the 4-Br-H 2 ip, the coordination ability and conformationally flexibility of the N-donor auxiliary. Compound 1 exhibits 3-fold interpenetrated 6 6 topology and compound 2 has a 4 12 topology. Compounds 3–4 have similar 3D pillar-layered structures based on 3,4-connected binodal net with the Schläfli symbol of (4·3 8 ). The thermal stabilities and photoluminescence properties of them were discussed in detail. - Graphical abstract: Four 3D Cd II coordination complexes on the basis of 4-bromoisophthalic acid (4-Br-H 2 ip) and two types of flexible (bbi, bbt) and semiflexible (bix, btx) N-donor ligands are prepared. They displayed diverse topology structures of 6 6 (1), 4 12 (2) and 4·3 8 (3−4), depending on the configuration of the 4-connected metal node, the coordination mode of the 4-Br-H 2 ip, the coordination ability and conformationally flexibility of the N-donor auxiliary ligand. - Highlights: • Four 3D Cd II coordination complexes based on 4-Br-H 2 ip and flexible/semiflexible N-donor ligands have been synthesized. • They displayed diverse topology structures of 6 6 for 1, 4 12 for 2 and 4·3 8 for 3–4. • The structural diversity depends on the configuration of 4-Br

DNA binding, antioxidant, cytotoxicity (MTT, lactate dehydrogenase, NO), and cellular uptake studies of structurally different nickel(II) thiosemicarbazone complexes: synthesis, spectroscopy, electrochemistry, and X-ray crystallography.

Science.gov (United States)

Prabhakaran, R; Kalaivani, P; Huang, R; Poornima, P; Vijaya Padma, V; Dallemer, F; Natarajan, K

2013-02-01

Three new nickel(II) thiosemicarbazone complexes have been synthesized and characterized by analytical, spectral, and single-crystal X-ray diffraction studies. In complex 1, the ligand 2-hydroxy-1-naphthaldehydethiosemicarbazone coordinated as a monobasic tridentate donor, whereas in complexes 2 and 3, the ligands salicylaldehyde-4(N)-ethylthiosemicarbazone and 2-hydroxy-1-naphthaldehyde-4(N)-ethylthiosemicarbazone coordinated as a dibasic tridentate donor. The DNA binding ability of the complexes in calf thymus DNA was explored by absorption and emission titration experiments. The antioxidant property of the new complexes was evaluated to test their free-radical scavenging ability. In vitro cytotoxicity assays were performed for the new complexes in A549 and HepG2 cell lines. The new compounds overcome cisplatin resistance in the A549 cell line and they were also active in the HepG2 cell line. The cellular uptake study showed the accumulation of the complexes in tumor cells depended on the nature of the ligand attached to the nickel ion.

Stereochemistry of charged nitrogen-aromatic interactions and its involvement in ligand-receptor binding

Science.gov (United States)

Verdonk, Marcel L.; Boks, Gertjan J.; Kooijman, Huub; Kanters, Jan A.; Kroon, Jan

1993-04-01

Recently, new evidence was found for the involvement of charged nitrogen-aromatic interactions in ligand-receptor binding. In this study we report two favourable orientations of a phenyl ring with respect to a R-N+(CH3)3 group, based on crystal structure statistics from the Cambridge Structural Database. In the first orientation, the phenyl ring is situated in between the substituents at about 4.5 Å from the nitrogen atom, and the ring is approximately oriented on the sphere around the nitrogen atom. In the second orientation, the phenyl ring is situated in the same direction as one of the N-C bonds at about 6.0 Å from the nitrogen atom, and the ring is tilted with respect to the sphere around the nitrogen atom. The same two orientations were also found in the crystal structures of three ligand-receptor complexes, which implies that these orientations probably play a major role in molecular recognition mechanisms.

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.

A one-dimensional cadmium(II complex supported by a sulfur–nitrogen mixed-donor ligand

Directory of Open Access Journals (Sweden)

Qian Gao

2009-07-01

Full Text Available In the title compound, catena-poly[cadmium(II-bis(μ-5-amino-1,3,4-thiadiazole-2-thiolato-κ2N3:S2;κ2S2:N3], [Cd(C2H2N3S22]n, the CdII ion is coordinated by two N atoms of the 1,3,4-thiadiazole rings from two ligands and two S atoms of sulfhydryl from two other ligands in a slightly distorted tetrahedral geometry. The ligands bridge CdII ions, forming one-dimensional chains along [001], which are connected by N—H...N and N—H...S hydrogen bonds into a three-dimensional network.

Cobalt(II Complexes with N,N,N-Scorpionates and Bidentate Ligands: Comparison of Hydrotris(3,5-dimethylpyrazol-1-ylborate Tp* vs. Phenyltris(4,4-dimethyloxazolin-2-ylborate ToM to Control the Structural Properties and Reactivities of Cobalt Centers

Directory of Open Access Journals (Sweden)

Toshiki Nishiura

2018-06-01

Full Text Available Scorpionate ligands Tp* (hydrotris(3,5-dimethylpyrazol-1-ylborate and ToM (tris(4,4-dimethyloxazolin-2-ylphenylborate complexes of cobalt(II with bidentate ligands were synthesized. Both Tp* and ToM coordinate to cobalt(II in a tridentate fashion when the bidentate ligand is the less hindered acetylacetonate. In crystal structures, the geometry of cobalt(II supported by the N3O2 donor set in the Tp* complex is a square-pyramid, whereas that in the ToM complex is close to a trigonal-bipyramid. Both Tp*- and ToM-acac complexes exhibit solvatochromic behavior, although the changing structural equilibria of these complexes in MeCN are quite different. In the bis(1-methylimidazol-2-ylmethylphenylborate (LPh complexes, Tp* retains the tridentate (к3 mode, whereas ToM functions as the bidentate (к2 ligand, giving the tetrahedral cobalt(II complex. The bowl-shaped cavity derived from the six methyl groups on ToM lead to susceptibility to the bulkiness of the opposite bidentate ligand. The entitled scorpionate compounds mediate hydrocarbon oxidation with organic peroxides. Allylic oxidation of cyclohexene occurs mainly on the reaction with tert-butyl hydroperoxide (TBHP, although the catalytic efficiency of the scorpionate ligand complexes is lower than that of Co(OAc2 and Co(acac2. On cyclohexane oxidation with meta-chloroperbenzoic acid (mCPBA, both ToM and Tp* complexes function as catalysts for hydroxylation. The higher electron-donating ToM complexes show faster initial reaction rates compared to the corresponding Tp* complexes.

A comprehensive in vitro biological investigation of metal complexes ...

African Journals Online (AJOL)

Md. Mahabob Ullah Mazumder

... Journal of Medicine journal homepage: http://www.elsevier.com/locate/ajme .... two new complexes containing Fe (III) and Mo(VI) of two tridentate ONO donor · sets ligands. Der Chem Sin. .... Pharmaceuticals (Basel). 2014;7(4):453–463. 13.

Group 4 Transition-Metal Complexes of an Aniline–Carbene–Phenol Ligand

KAUST Repository

Despagnet-Ayoub, Emmanuelle

2013-05-24

Attempts to install a tridentate aniline-NHC-phenol (NCO) ligand on titanium and zirconium led instead to complexes resulting from unexpected rearrangement pathways that illustrate common behavior in carbene-early- transition-metal chemistry. © 2013 American Chemical Society.

Low temperature X-ray structure analyses combined with NBO studies of a new heteroleptic octa-coordinated Holmium(III) complex with N,N,N-tridentate hydrazono-phthalazine-type ligand

Science.gov (United States)

Soliman, Saied M.; El-Faham, Ayman

2018-04-01

The new heteroleptic [HoL(H2O)5]Br3 complex, L is hydrazono-phthalazine ligand, is synthesized and its molecular structure aspects were analyzed using single crystal X-ray structure (SCXRD), Hirshfeld (HF) analysis, quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) method. The SCXRD showed that the Ho is octa-coordinated with one N,N,N-tridentate ligand L and five water molecules. The HF analysis is used to analyze the molecular packing in the [HoL(H2O)5]Br3crystal structure. The complex cations are connected via strong Osbnd H⋯Br and Nsbnd H⋯Br H-bonding interactions which have greater importance than the Csbnd H⋯Br contacts. Also, all the Hosbnd N and Hosbnd O bonds have the characteristics of closed shell interactions using QTAIM. The natural orbitals included in these interactions were analyzed using NBO method. The alpha LP*(8)Ho and beta LP*(4)Ho which have mainly s-orbital characters are the most important anti-bonding natural orbitals included in all Ho-N and Hosbnd O bonds. The rest of the Ho anti-bonding orbitals which have either p or d-orbital characters shared partially in the Ho-ligands interactions. Natural charges analysis revealed the presence of significant amount of electron density (0.9225-0.9300 e) transferred from the ligands to Ho (2.0700-2.0775 e). Spherical spin density with ∼4.0 e is predicted over the Ho atom.

Synthesis and Characterization of 4-Benzyloxybenzaldehyde-4-methyl-3-thiosemicarbazone (Containing Sulphur and Nitrogen Donor Atoms and Its Cd(II Complex

Directory of Open Access Journals (Sweden)

Lakshmi Narayana Suvarapu

2015-12-01

Full Text Available A chelating agent, 4-benzyloxybenzaldehyde-4-methyl-3-thiosemicarbazone (BBMTSC, containing sulphur and nitrogen donor atoms was synthesized and applied as a ligand for the chelation of Cd(II. Both the BBMTSC and its Cd(II complex were characterized by elemental analysis, UV-Vis absorption spectra, Fourier transform infrared spectroscopy (FT-IR, mass spectra, nuclear magnetic resonance spectroscopy (NMR, X-ray powder diffraction (XRD, and field emission scanning electron microscopy (FESEM. The FTIR spectra confirmed the formation of both BBMTSC and its Cd(II complex. XRD revealed the polycrystalline nature of the synthesized compounds. BBMTSC exhibited a flake-like micro-rod morphology, whereas the Cd(II complex had a flower-like nanorod structure.

Synthesis and spectral studies of some lanthanide(III) complexes ...

African Journals Online (AJOL)

... compounds were characterized through various physico-chemical studies. The coordinating ligand DABAAPS behave as tridentate N,N,O-donors. The central metal ion displays the coordination number nine in these complexes. Thermal stabilities of these complexes were also studied through thermogravimetric analysis.

Syntheses, spectroscopic and magnetic properties of polystyrene-anchored coordination compounds of thiazolidinone

Directory of Open Access Journals (Sweden)

D. Kumar

2014-01-01

Full Text Available The reaction between polystyrene 3-formylsalicylate and furoic acid hydrazide in DMF in the presence of ethyl acetate results in the formation of polystyrene N-(2-carbamoylfuranyl-3'-carboxy-2'-hydroxybenzylideneimine (I. A benzene suspension of I reacts with mercaptoacetic acid and forms the polystyrene N-(2-carbamoylfuranyl-C-(3'-carboxy-2'-hydroxyphenylthiazolidin-4-one, PSCH2–LH2 (II. A DMF suspension of II reacts with Mn(II, Ni(II, Cd(II, Fe(III and UO2(VI ions and forms the polystyrene-anchored coordination compounds of the types, [PSCH2–LMn(DMF3], [PSCH2–LNi(DMF3], [PSCH2–LCd(DMF], [PSCH2–LH2FeCl3] and [PSCH2–LHUO2(NO3(DMF]. The polystyrene-anchored coordination compounds have been characterized on the basis of elemental analyses, spectral (IR, reflectance studies and magnetic susceptibility measurements. II acts as a neutral tridentate ONO donor ligand in [PSCH2–LH2FeCl3], a monobasic tridentate ONO donor ligand in [PSCH2–LHUO2(NO3(DMF], a dibasic tridentate ONO donor ligand in [PSCH2–LMn(DMF3], [PSCH2–LNi(DMF3] and [PSCH2–LCd(DMF]. A tetrahedral structure for Cd(II and an octahedral structure for Mn(II, Ni(II, Fe(III and a square-antiprism geometry for UO2(VI complex are suggested. DOI: http://dx.doi.org/10.4314/bcse.v28i1.4

Hexacoordinated mixed-ligand complexes of vanadium(IV) and copper(II)

International Nuclear Information System (INIS)

Islam, M.S.; Motahera Begum; Roy, H.N.; Haroon, S.A.Q.M.

1996-01-01

The literature reports simple complexes of metal ions with Schiff bases derived from amino acids. But their mixed-ligand complexes are very rare. Keeping this fact in mind, some new mixed ligand complexes of V IV and Cu II with tridentate Schiff bases derived from glycine, salicylaldehyde and amino bases, e.g. quinoline (Q), isoquinoline (IQ), 2-picoline (2-pic), 4-picoline (4-pic) and pyridine (Py) were prepared and studied. 6 refs., 1 tab

Mechanically-induced solvent-less synthesis of cobalt and nickel complexes of cimetidine

Directory of Open Access Journals (Sweden)

Adedibu Clement Tella

2011-09-01

Full Text Available Solvent-less synthesis of [Co(CIM2](SO4 and [Ni(CIM2](OAC2 by grinding of CoSO4 and Ni(CH3COO2.4H2O with cimetidine without any solvent is described. The complexes have been characterized by elemental analysis, melting point, AAS, conductivity measurements, TLC, infrared and UV-Vis spectroscopies as well as X-ray powder diffraction. Cimetidine was found to be bidentate or tridentate ligand. Cobalt ion coordinate with cimetidine through the sulphur atom in the thiol group, nitrogen atom of imidazole ring and the nitrogen atom of the secondary amine to give an octahedral geometry with ligand acting as tridentate whereas nickel ion coordinates through the sulphur atom in the thiol group, nitrogen atom of imidazole ring to give tetrahedral structure with ligand acting as bidentate. X-Ray diffraction patterns of the complex were different from that of the ligand suggesting formation of coordination compounds. The method is quick and gives a quantatively yield, without the need for solvents or external heating. Clearly, it can present higher efficiency in terms of materials, energy and time compared to classical solution phase synthesis.

Synthesis and characterization of a Schiff base Cobalt (III) complex ...

African Journals Online (AJOL)

Schiff base molecule acts as tridentate ligand to form two five-membered chelate rings with the Co(III) ion. In the crystal structure three meridionally arranged nitrogen atoms from three azide ligands complete a distorted octahedral geometry around the metal center. The distortion from an ideal octahedron is evident from the ...

Complexation of trivalent cationic lanthanides by N.O donor ligands: physico-chemical studies of the association and selectivity in solution

International Nuclear Information System (INIS)

Bravard, F.

2004-01-01

The aim of this work is to study the complexation of f-elements in solution by ligands incorporating N-heterocyclic donors. These ligands display interesting properties for the selective separation of An(III)/Ln(III) have been studied to obtain a better understanding of the coordination properties with f-elements and to develop more selective extractants. The hepta-dentate ligand tpaam shows an affinity for Ln(III) similar to the tetradentate ligand tpa in water even when the three additional amide groups are bonded to the metal. Even though the complexation with tpa is exothermic, that with tpaam is endothermic with a more positive entropy. The dehydration of the cation disfavours the formation of Ln(III) complexes with ligands containing weak donors. The analysis of the solution paramagnetic relaxation times of the tpaam complexes is in agreement with data in the solid-state. There is little difference between the formation constants of the Ln 3+ complexes with different ligands (tpaam, tpzen, tpa and tpza) as determined by UV-vis spectrophotometry in anhydrous acetonitrile. The limitations encountered during this study are intrinsic to the ligands studied. The preliminary study of two tetrapodal ligands containing acid and pyridine groups (L py )or pyrazine (L pz ) show the formation of 1:1 complexes in water. Analysis of the formation constants of the corresponding Gd(III) complexes shows that replacement of a pyridine group by pyrazine result in a loss of stability of 1.6 logarithmic units. (author) [fr

Synthesis, characterization, spectroscopic and theoretical studies of new zinc(II), copper(II) and nickel(II) complexes based on imine ligand containing 2-aminothiophenol moiety

Science.gov (United States)

Shafaatian, Bita; Mousavi, S. Sedighe; Afshari, Sadegh

2016-11-01

New dimer complexes of zinc(II), copper(II) and nickel(II) were synthesized using the Schiff base ligand which was formed by the condensation of 2-aminothiophenol and 2-hydroxy-5-methyl benzaldehyde. This tridentate Schiff base ligand was coordinated to the metal ions through the NSO donor atoms. In order to prevent the oxidation of the thiole group during the formation of Schiff base and its complexes, all of the reactions were carried out under an inert atmosphere of argon. The X-ray structure of the Schiff base ligand showed that in the crystalline form the SH groups were oxidized to produce a disulfide Schiff base as a new double Schiff base ligand. The molar conductivity values of the complexes in dichloromethane implied the presence of non-electrolyte species. The fluorescence properties of the Schiff base ligand and its complexes were also studied in dichloromethane. The products were characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis, and conductometry. The crystal structure of the double Schiff base was determined by single crystal X-ray diffraction. Furthermore, the density functional theory (DFT) calculations were performed at the B3LYP/6-31G(d,p) level of theory for the determination of the optimized structures of Schiff base complexes.

N6-Benzyladenosine Derivatives as Novel N-Donor Ligands of Platinum(II Dichlorido Complexes

Directory of Open Access Journals (Sweden)

Ján Vančo

2013-06-01

Full Text Available The platinum(II complexes trans-[PtCl2(Ln2]∙xSolv 1–13 (Solv = H2O or CH3OH, involving N6-benzyladenosine-based N-donor ligands, were synthesized; Ln stands for N6-(2-methoxybenzyladenosine (L1, involved in complex 1, N6-(4-methoxy-benzyladenosine (L2, 2, N6-(2-chlorobenzyladenosine (L3, 3, N6-(4-chlorobenzyl-adenosine (L4, 4, N6-(2-hydroxybenzyladenosine (L5, 5, N6-(3-hydroxybenzyl-adenosine (L6, 6, N6-(2-hydroxy-3-methoxybenzyladenosine (L7, 7, N6-(4-fluoro-benzyladenosine (L8, 8, N6-(4-methylbenzyladenosine (L9, 9, 2-chloro-N6-(3-hydroxy-benzyladenosine (L10, 10, 2-chloro-N6-(4-hydroxybenzyladenosine (L11, 11, 2-chloro-N6-(2-hydroxy-3-methoxybenzyladenosine (L12, 12 and 2-chloro-N6-(2-hydroxy-5-methylbenzyladenosine (L13, 13. The compounds were characterized by elemental analysis, mass spectrometry, IR and multinuclear (1H-, 13C-, 195Pt- and 15N- and two-dimensional NMR spectroscopy, which proved the N7-coordination mode of the appropriate N6-benzyladenosine derivative and trans-geometry of the title complexes. The complexes 1–13 were found to be non-toxic in vitro against two selected human cancer cell lines (HOS and MCF7; with IC50 > 50.0 µM. However, they were found (by ESI-MS study to be able to interact with the physiological levels of the sulfur-containing biogenic biomolecule L-methionine by a relatively simple 1:1 exchange mechanism (one Ln molecule was replaced by one L-methionine molecule, thus forming a mixed-nitrogen/sulfur-ligand dichlorido-platinum(II coordination species.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

The compounds with the general formula [RuX(EPh3)2(L)] (X = Cl or Br; E = P or As; L = bifunctional tridentate ONO/ONS donor Schiff base ligand) were characterized by infrared, electronic, electron paramagnetic resonance spectroscopy and elemental analyses. Spectroscopic investigation reveals coordination of Schiff ...

Probing the influence of N-donor capping ligands on supramolecular assembly in molecular uranyl materials

Energy Technology Data Exchange (ETDEWEB)

Carter, Korey P.; Kalaj, Mark; Cahill, Christopher L. [Department of Chemistry, The George Washington University, Washington, DC (United States)

2016-01-15

The syntheses and crystal structures of six new compounds containing the UO{sub 2}{sup 2+} cation, 3,5-dichlorobenzoic acid, and a chelating N-donor [2,2'-bipyridine (bipy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (dimethylphen), 2,2{sup '}:6{sup '},2''-terpyridine (terpy), 4{sup '}-chloro-2,2{sup '}:6{sup '},2''-terpyridine (Cl-terpy), or 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ)] are reported. Single-crystal X-ray diffraction analysis of these materials enabled the exploration of the structural relationship between the benzoic acids and the chelating N-donor as well as providing a platform to evaluate the effects of ligand choice on uranyl hydrolysis and subsequent oligomerization. At an unadjusted pH (ca. 3), a mix of uranyl monomers and dimers are observed, dimer formation resulting from both bridging carboxylate linkers and hydroxo bridges. Assembly by halogen- and hydrogen-bonding interactions as well as π-π interactions was observed depending on the experimental conditions utilized. Further, spectroscopic characterization (both vibrational and luminescence) of complexes 1, 4, and 5 to explore the effects of the electron-donating ability of the capping ligand on the corresponding uranyl luminescence and vibrational spectra suggests that there is a relationship between the observed bathochromic shifts and the electron-donating ability of the capping ligands. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Probing the influence of N-donor capping ligands on supramolecular assembly in molecular uranyl materials

International Nuclear Information System (INIS)

Carter, Korey P.; Kalaj, Mark; Cahill, Christopher L.

2016-01-01

The syntheses and crystal structures of six new compounds containing the UO 2 2+ cation, 3,5-dichlorobenzoic acid, and a chelating N-donor [2,2'-bipyridine (bipy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (dimethylphen), 2,2 ' :6 ' ,2''-terpyridine (terpy), 4 ' -chloro-2,2 ' :6 ' ,2''-terpyridine (Cl-terpy), or 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ)] are reported. Single-crystal X-ray diffraction analysis of these materials enabled the exploration of the structural relationship between the benzoic acids and the chelating N-donor as well as providing a platform to evaluate the effects of ligand choice on uranyl hydrolysis and subsequent oligomerization. At an unadjusted pH (ca. 3), a mix of uranyl monomers and dimers are observed, dimer formation resulting from both bridging carboxylate linkers and hydroxo bridges. Assembly by halogen- and hydrogen-bonding interactions as well as π-π interactions was observed depending on the experimental conditions utilized. Further, spectroscopic characterization (both vibrational and luminescence) of complexes 1, 4, and 5 to explore the effects of the electron-donating ability of the capping ligand on the corresponding uranyl luminescence and vibrational spectra suggests that there is a relationship between the observed bathochromic shifts and the electron-donating ability of the capping ligands. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of N'-(furan-3-ylmethylene)-2-(4-methoxyphenylamino)acetohydrazide.

Science.gov (United States)

Emam, Sanaa M; El-Saied, Fathy A; Abou El-Enein, Saeyda A; El-Shater, Heba A

2009-03-01

Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of furan-2-carbaldehyde 4-methoxy-N-anilinoacetohydrazone were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and (1)H NMR spectra as well as magnetic moment and molar conductivity. Mononuclear complexes are obtained with 1:1 molar ratio except complexes 3 and 9 which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a neutral bidentate one and coordination occurs via the carbonyl oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the enolic oxygen atom, azomethine nitrogen atom and the oxygen atom of furan ring. Moreover, the ligand behaves as a neutral tridentate and coordination occurs via the carbonyl oxygen, azomethine nitrogen and furan oxygen atoms as well as a monobasic bidentate and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complex 10 possesses a square planar geometry. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes.

New oxozirconium(IV) complexes with the schiff bases derived from salicylaldehyde or substituted salicylaldehydes and o-aminobenzyl alcohol

Energy Technology Data Exchange (ETDEWEB)

Syamal, A [Kurukshetra Univ. (India). Dept. of Applied Sciences and Humanities; Kumar, D [Regional Engineering Coll., Kurukshetra (India). Dept. of Chemistry

1980-10-01

Several new oxozirconium(IV) complexes with the schiff bases obtained from salicylaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 5-nitrosalicylaldehyde, 4-methoxysalicylaldehyde, 5-methoxysalicylaldehyde, 3-ethoxysalicylaldehyde, 3,5-dichlorosalicylaldehyde or 2-hydroxy-1-naphthaldehyde and 0-aminobenzyl alcohol have been synthesized and characterized on the basis of elemental analysis, molecular weight, electrical conductance, infrared spectral and magnetic susceptibility measurements. The schiff bases behave as monobasic, tridentate ONO donor ligands. The complexes are of the type ZrO(LH)/sub 2/ (where LH/sub 2/ = tridentate schiff base) and are seven-coordinated. The complexes are monomers, non-electrolytes and diamagnetic. Changes in the ..nu..C=N, ..nu..C-0 (phenolic) and ..nu..C-0 (alchoholic) frequencies have been followed to find out the coordination sites of the ligands.

Regio- and stereo-selective polymerization of 1,3-butadiene catalyzed by phosphorus–nitrogen PN3-pincer cobalt(ii) complexes

KAUST Repository

Gong, Dirong; Zhang, Xuequan; Huang, Kuo-Wei

2016-01-01

ligand through the pyridinyl nitrogen, the pyrazol nitrogen and the phosphorus donor, with a long Co-P bond distance indicating a labile character. On activation with AlEt2Cl, Al2Et3Cl3, MAO, [Ph3C]+[B(C6F5)4]-/AliBu3 or AliBu3, cis-1,4 selective

QSAR studies of multidentate nitrogen ligands used in lanthanide and actinide extraction processes

International Nuclear Information System (INIS)

Drew, Michael G.B.; Hudson, Michael J.; Youngs, Tristan G.A.

2004-01-01

Quantitative structure activity relationships (QSARs) have been developed to optimise the choice of nitrogen heterocyclic molecules that can be used to separate the minor actinides such as americium(III) from europium(III) in the aqueous PUREX raffinate of nuclear waste. Experimental data on distribution coefficients and separation factors (SFs) for 47 such ligands have been obtained and show SF values ranging from 0.61 to 100. The ligands were divided into a training set of 36 molecules to develop the QSAR and a test set of 11 molecules to validate the QSAR. Over 1500 molecular descriptors were calculated for each heterocycle and the Genetic Algorithm was used to select the most appropriate for use in multiple regression equations. Equations were developed fitting the separation factors to 6-8 molecular descriptors which gave r 2 values of >0.8 for the training set and values of >0.7 for the test set, thus showing good predictive quality. The descriptors used in the equations were primarily electronic and steric. These equations can be used to predict the separation factors of nitrogen heterocycles not yet synthesised and/or tested and hence obtain the most efficient ligands for lanthanide and actinide separation

Diverse Cd(II) compounds based on N-benzoyl-L-glutamic acid and N-donor ligands: Structures and photoluminescent properties

International Nuclear Information System (INIS)

Ma, Ning; Guo, Wei-Ying; Song, Hui-Hua; Yu, Hai-Tao

2016-01-01

Five new Cd(II) coordination polymers with N-benzoyl-L-glutamic acid (H_2bzgluO) and different N-donor ligands, [Cd(bzgluO)(2,2′-bipy)(H_2O)]_n (1), [Cd(bzgluO)(2,4′-bipy)_2(H_2O)·3H_2O]_n (2), [Cd(bzgluO)(phen)·H_2O]_n (3), [Cd(bzgluO)(4,4′-bipy)(H_2O)]_n (4), [Cd(bzgluO)(bpp)(H_2O)·2H_2O]_n (5) were synthesized (2,2′-bipy=2,2′-bipyridine, 2,4′-bipy=2,4′-bipyridine, phen=1,10-phenanthroline, 4,4′-bipy=4,4′-bipyridine, bpp=1,3-di(4-pyridyl)propane). Compounds 1–2 exhibit a 1D single-chain structure. Compound 1 generates a 2D supramolecular structure via π–π stacking and hydrogen bonding, 3D architecture of compound 2 is formed by hydrogen bonding. Compound 3 features a 1D double-chain structure, which are linked by π–π interactions into a 2D supramolecular layer. Compounds 4-5 display a 2D network structure. Neighboring layers of 4 are extended into a 3D supramolecular architecture through hydrogen bonding. The structural diversity of these compounds is attributed to the effect of ancillary N-donor ligands and coordination modes of H_2bzgluO. Luminescent properties of 1–5 were studied at room temperature. Circular dichroism of compounds 1, 2 and 5 were investigated. - Graphical abstract: Five new Cd(II) metal coordination compounds with H_2bzgluO and different N-donor ligands were synthesized and characterized. Compounds 1, 2 and 3 present 1D structures, compounds 4 and 5 display 2D networks. Results indicate that auxiliary ligands and coordination modes of H_2bzgluO play an important role in governing the formation of final frameworks, and the hydrogen-bonding and π–π stacking interactions contribute the formation of the diverse supramolecular architectures. Furthermore, the different crystal structures influence the emission spectra significantly. - Highlights: • It is rarely reported that complexes prepared with N-benzoyl-L-glutamic acid. • Each complex displays diverse structures and different supramolecular

Carbonyl complexes of rhodium with N-donor ligands: factors determining the formation of terminal versus bridging carbonyls

NARCIS (Netherlands)

Dzik, W.I.; Creusen, C.; de Gelder, R.; Peters, T.P.J.; Smits, J.M.M.; de Bruin, B.

2010-01-01

Cationic rhodium carbonyl complexes supported by a series of different N-3- and N-4-donor ligands were prepared, and their ability to form carbonyl-bridged species was evaluated. Complex [Rh(K3-bpa)(cod)r (1(+)) (bpa = bis(2-picolyBamine, cod = cis,cis-1,5-cyclooctadiene) reacts with I bar of CO to

Utilization of mixed ligands to construct diverse Ni(II)-coordination polymers based on terphenyl-2,2′,4,4′-tetracarboxylic acid and varied N-donor co-ligands

International Nuclear Information System (INIS)

Wang, Chao; Zhao, Jun; Xia, Liang; Wu, Xue-Qian; Wang, Jian-Fang; Dong, Wen-Wen; Wu, Ya-Pan

2016-01-01

Three new coordination polymers, namely, {[Ni(H 2 L)(bix)(H 2 O) 2 ]·2h 2 O} n (1), {[Ni(HL)(Hdpa)(H 2 O) 2 ]·H 2 O} n (2), {[Ni(L) 0.5 (bpp)(H 2 O)]·H 2 O} n (3) (H 4 L=terphenyl-2,2′,4,4′-tetracarboxylic acid; bix=1,4-bis(imidazol-1-ylmethyl)benzene; dpa =4,4′-dipyridylamine; bpp=1,3-bis(4-pyridyl)propane), based on rigid H 4 L ligand and different N-donor co-ligands, have been synthesized under hydrothermal conditions. Compound 1 features a 3D 4-connected 6 6 -dia-type framework with H 4 L ligand adopts a μ 2 -bridging mode with two symmetry-related carboxylate groups in μ 1 -η 1 :η 0 monodentate mode. Compound 2 displays a 1D [Ni(HL)(Hdpa)] n ribbon chains motif, in which the H 4 L ligand adopts a μ 2 -bridging mode with two carboxylate groups in μ 1 -η 1 :η 1 and μ 1 -η 1 :η 0 monodentate modes, while 3 possesses a (4,4)-connected 3D frameworks with bbf topology, with H 4 L ligand displays a μ 4 -bridging coordination mode. The H 4 L ligand displays not only different deprotonated forms but also diverse coordination modes and conformations. The structural diversities among 1–3 have been carefully discussed, and the roles of N-donor co-ligands in the self-assembly of coordination polymers have been well documented. - Graphical abstract: Three nickel coordination polymers with different architectures based on mixed ligand system were synthesized and structurally characterized. Topology analyses indicate that 1 shows the 4-connected 6 6 -dia net, 1D ribbon chains for 2 and 3D (4,4)-connected bbf network for 3. Display Omitted - Highlights: • Three Ni-based coordination polymers with distinct features have been prepared. • Compound 1 features a 3D 4-connected 66-dia-type framework, 2 displays a 1D [Ni(HL)(Hdpa)] n ribbon chains motif, while 3 possesses a (4,4)-connected 3D frameworks with bbf topology. • The “mixed ligand assembled” strategy is significant potential for network design.

Role of Killer Immunoglobulin-Like Receptor and Ligand Matching in Donor Selection

Directory of Open Access Journals (Sweden)

Meral Beksaç

2012-01-01

Full Text Available Despite all efforts to improve HLA typing and immunosuppression, it is still impossible to prevent severe graft versus host disease (GVHD which can be fatal. GVHD is not always associated with graft versus malignancy and can prevent stem cell transplantation from reaching its goals. Overall T-cell alloreactivity is not the sole mechanism modulating the immune defense. Innate immune system has its own antigens, ligands, and mediators. The bridge between HLA and natural killer (NK cell-mediated reactions is becoming better understood in the context of stem cell transplantation. Killer immunoglobulin-like receptors (KIRs constitute a wide range of alleles/antigens segregated independently from the HLA alleles and classified into two major haplotypes which imprints the person's ability to suppress or to amplify T-cell alloreactivity. This paper will summarize the impact of both activating and inhibitory KIRs and their ligands on stem cell transplantation outcome. The ultimate goal is to develop algorithms based on KIR profiles to select donors with maximum antileukemic and minimum antihost effects.

A trident dithienylethene-perylenemonoimide dyad with super fluorescence switching speed and ratio

Science.gov (United States)

Li, Chong; Yan, Hui; Zhao, Ling-Xi; Zhang, Guo-Feng; Hu, Zhe; Huang, Zhen-Li; Zhu, Ming-Qiang

2014-12-01

Photoswitchable fluorescent diarylethenes are promising in molecular optical memory and photonic devices. However, the performance of current diarylethenes is far from satisfactory because of the scarcity of high-speed switching capability and large fluorescence on-off ratio. Here we report a trident perylenemonoimide dyad modified by triple dithienylethenes whose photochromic fluorescence quenching ratio at the photostationary state exceeds 10,000 and the fluorescence quenching efficiency is close to 100% within seconds of ultraviolet irradiation. The highly sensitive fluorescence on/off switching of the trident dyad enables recyclable fluorescence patterning and all-optical transistors. The prototype optical device based on the trident dyad enables the optical switching of incident light and conversion from incident light wavelength to transmitted light wavelength, which is all-optically controlled, reversible and wavelength-convertible. In addition, the trident dyad-staining block copolymer vesicles are observed via optical nanoimaging with a sub-100 nm resolution, portending a potential prospect of the dithienylethene dyad in super-resolution imaging.

CO2 activation through silylimido and silylamido zirconium hydrides supported on N-donor chelating SBA15 surface ligand

KAUST Repository

Pasha, Fahran Ahmad; Bendjeriou-Sedjerari, Anissa; Abou-Hamad, Edy; Huang, Kuo-Wei; Basset, Jean-Marie

2016-01-01

Density functional theory calculations and 2D 1H-13C HETCOR solid state NMR spectroscopy prove that CO2 can probe, by its own reactivity, different types of N-donor surface ligands on SBA15-supported ZrIV hydrides: [(≡Si-O-)(≡Si-N=)[Zr]H] and [(≡Si

Synthesis and structural studies of Cp{sup *} rhodium and Cp{sup *} iridium complexes of picolinic hydrazine ligand

Energy Technology Data Exchange (ETDEWEB)

Palepu, Narasinga Rao; Kollipara, Mohan Rao [Centre for Advanced Studies in Chemistry, North-Eastern Hill University, Shillong (India); Kaminsky Werner [Dept. of Chemistry, University of Washington, Seattle (United States)

2017-01-15

A series of Cp{sup *}Rh and Cp{sup *}Ir complexes of picolinic hydrazine ligand are synthesized and characterized. Picolinic hydrazine has yielded only dinuclear complexes in the case of rhodium metal whereas both mono and dinuclear complexes with iridium metal. Iridium complexes are formed as quaternary salts by the migration of the N–H proton onto the adjacent amine group of the hydrazine after binding to the metal. Picolinic hydrazine acts as nitrogen and oxygen donor ligand in the form of bi and tetradentate bonding modes.

A new tridentate Schiff base Cu(II) complex: synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra.

Science.gov (United States)

Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

2013-06-01

A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms. Copyright © 2013 Elsevier B.V. All rights reserved.

Diverse Cd(II) compounds based on N-benzoyl-L-glutamic acid and N-donor ligands: Structures and photoluminescent properties

Energy Technology Data Exchange (ETDEWEB)

Ma, Ning; Guo, Wei-Ying; Song, Hui-Hua, E-mail: songhuihua@mail.hebtu.edu.cn; Yu, Hai-Tao, E-mail: haitaoyu@mail.hebtu.edu.cn

2016-01-15

Five new Cd(II) coordination polymers with N-benzoyl-L-glutamic acid (H{sub 2}bzgluO) and different N-donor ligands, [Cd(bzgluO)(2,2′-bipy)(H{sub 2}O)]{sub n} (1), [Cd(bzgluO)(2,4′-bipy){sub 2}(H{sub 2}O)·3H{sub 2}O]{sub n} (2), [Cd(bzgluO)(phen)·H{sub 2}O]{sub n} (3), [Cd(bzgluO)(4,4′-bipy)(H{sub 2}O)]{sub n} (4), [Cd(bzgluO)(bpp)(H{sub 2}O)·2H{sub 2}O]{sub n} (5) were synthesized (2,2′-bipy=2,2′-bipyridine, 2,4′-bipy=2,4′-bipyridine, phen=1,10-phenanthroline, 4,4′-bipy=4,4′-bipyridine, bpp=1,3-di(4-pyridyl)propane). Compounds 1–2 exhibit a 1D single-chain structure. Compound 1 generates a 2D supramolecular structure via π–π stacking and hydrogen bonding, 3D architecture of compound 2 is formed by hydrogen bonding. Compound 3 features a 1D double-chain structure, which are linked by π–π interactions into a 2D supramolecular layer. Compounds 4-5 display a 2D network structure. Neighboring layers of 4 are extended into a 3D supramolecular architecture through hydrogen bonding. The structural diversity of these compounds is attributed to the effect of ancillary N-donor ligands and coordination modes of H{sub 2}bzgluO. Luminescent properties of 1–5 were studied at room temperature. Circular dichroism of compounds 1, 2 and 5 were investigated. - Graphical abstract: Five new Cd(II) metal coordination compounds with H{sub 2}bzgluO and different N-donor ligands were synthesized and characterized. Compounds 1, 2 and 3 present 1D structures, compounds 4 and 5 display 2D networks. Results indicate that auxiliary ligands and coordination modes of H{sub 2}bzgluO play an important role in governing the formation of final frameworks, and the hydrogen-bonding and π–π stacking interactions contribute the formation of the diverse supramolecular architectures. Furthermore, the different crystal structures influence the emission spectra significantly. - Highlights: • It is rarely reported that complexes prepared with N-benzoyl-L-glutamic acid

Synthesis of Copper Nanoparticles Coated with Nitrogen Ligands

Directory of Open Access Journals (Sweden)

Rubén Sierra-Ávila

2014-01-01

Full Text Available The synthesis of copper nanoparticles was studied by wet chemical methods using copper sulfate pentahydrate (CuSO4·5H2O and nitrogen ligands allylamine (AAm and polyallylamine (PAAm as stabilizers. The results suggest that the use of these ligands leads to the exclusive formation of metallic copper nanoparticles (Cu-NPs. The use of partially crosslinked polyallylamine (PAAmc leads to nanoparticles (NPs with low yields and high coating content, while linear PAAm leads to NPs with high yields and low coating content. The chemical composition of the particles was determined by XRD and average particle diameters were determined by the Debye-Scherrer equation. TGA analysis provided evidence of the content and thermal stability of the coating on the nanoparticles and PAAm. The morphology, particle size distribution, and presence of PAAm coating were observed through TEM. The use of AAm in the synthesis of NPs could be a good alternative to reduce costs. By using TGA, TEM, and DSC techniques, it was determined that synthesized NPs with AAm presented a coating with similar characteristics to NPs with PAAm, suggesting that AAm underwent polymerization during the synthesis.

Synthesis, Crystal Structure and Luminescent Property of A Novel Cd(II) Coordination Polymer with Bis-imidazole Ligand

International Nuclear Information System (INIS)

Zhou, Yong Hong

2013-01-01

The key to the successful design of metal-organic coordination polymers is the judicious selection of organic ligand. Recently, polydentate aromatic nitrogen heterocyclic ligands with five-membered rings have been well-studied in the construction of supramolecular structure for their N-coordinated sites apt to coordinating to transition metals. Similar to six-membered N-heterocyclic ligands, the azole-based five-membered N-heterocyclic ligands, such as imidazoles, triazoles and tetrazoles have been extensively employed in the construction of various coordination polymers with diverse topologies and interesting properties. The bis(azole) ligands in which N-donor azole rings (imidazole, triazole, or tetrazole) are separated by alkyl, (CH 2 ) n , spacers are good choices for flexible bridging ligands. The conformational flexibility of the spacers makes the ligands adaptable to various coordination networks with one-, two-, and three dimensional structures

3,4-Dimethyl diphenyldithiophosphate of mononuclear cobalt(II) with N-donor ligands: Synthesis, structural characterization, DFT and antibacterial studies

Science.gov (United States)

Kumar, Sandeep; Kour, Gurpreet; Schreckenbach, Georg; Andotra, Savit; Hundal, Geeta; Sharma, Vishal; Jaglan, Sundeep; Pandey, Sushil K.

2017-08-01

3,4-Dimethyl diphenyldithiophosphate of cobalt(II) with N-donor ligands [{(ArO)2PS2}2CoL2] [Ar = 3,4-(CH3)2C6H3 (1-3); L = C5H5N (1), 3,4-(CH3)2C5H3N (2) and 4-(C2H5)C5H4N (3)] have been synthesized and characterized by elemental analyses, infrared spectroscopy (IR), powder X-ray diffraction (PXRD) and single crystal X-ray analysis. Complex 1 crystallizes in the monoclinic space group P21/n whereas complexes 2 and 3 crystallize in the triclinic space group Pbar1. The crystal structures of complexes 1-3 reveal mononuclear units with the Co(II) center chelated in bidentate fashion by four S atoms of the two diphenyldithiophosphate ligands. The N atoms from two donor ligands are axially coordinated, leading to distorted octahedral geometry around Co(II). The complexes have been optimized using density functional theory (DFT), structural parameters have been calculated, and the energy gaps of the frontier orbitals (HOMO-LUMO) have been predicted. Mayer bond orders have also been calculated. Structural parameters from the crystallographic and DFT studies are in good agreement with each other. To explore the biological potential, complexes were evaluated for their antibacterial activity against three bacterial strains. The bacterial growth inhibition capacity of the ligand and complexes followed the order of 3 > 2 > 1 > L1.

Synthesis and photoluminescence properties of silver(I) complexes based on N-benzoyl-L-glutamic acid and N-donor ligands with different flexibility

Science.gov (United States)

Yan, Ming-Jie; Feng, Qi; Song, Hui-Hua

2016-05-01

By changing the N-donor ancillary ligand, three novel silver (I) complexes {[Ag(HbzgluO) (4,4‧-bipy)]·H2O}n (1), {[Ag2(HbzgluO)2 (bpe)2]·2H2O}n (2) and {[Ag(HbzgluO)(bpp)]·2H2O}n (3) (H2bzgluO = N-benzoyl-L-glutamic acid, 4,4‧-bipy = 4,4ˊ-bipyridine, bpe = 1,2-di(4-pyridyl)ethane, bpp = 1,3-di(4-pyridyl)propane) were synthesized. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). In this study, the N-donor ligands are changed from rigidity (4,4‧-bipy), quasi-flexibility (bpe) to flexibility (bpp), the structures of complexes also change. Complex 1 features a 1D chain structure which is further linked together to construct a 2D supramolecular structure through hydrogen bonds. Complex 2 is a 1D double-chains configuration which eventually forms a 3D supramolecular network via hydrogen bonding interactions. Whereas, complex 3 exhibits a 2D pleated grid structure which is linked by hydrogen bonding interactions into a 3D supramolecular network. The present observations demonstrate that the modulation of coordination polymers with different structures can accomplish by changing the spacer length of N-donor ligands. In addition, the solid-state circular dichroism (CD) spectra indicated that compound 2 exhibited negative cotton effect which originated from the chiral ligands H2bzgluO and the solid-state fluorescence spectra of the three complexes demonstrated the auxiliary ligands have influence on the photoluminescence properties of the complexes.

Synthesis, structures and Helicobacter pylori urease inhibitory activity of copper(II) complexes with tridentate aroylhydrazone ligands.

Science.gov (United States)

Pan, Lin; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Zhu, Hailiang; Zhao, Xinlu; Qu, Dan; Niu, Fang; You, Zhonglu

2016-06-01

A series of new copper(II) complexes were prepared. They are [CuL(1)(NCS)] (1), [CuClL(1)]·CH3OH (2), [CuClL(2)]·CH3OH (3), [CuL(3)(NCS)]·CH3OH (4), [CuL(4)(NCS)]·0.4H2O (5), and [CuL(5)(bipy)] (6), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, 4-bromo-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide and 2-chloro-N'-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, respectively, L(5) is the dianionic form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra and single crystal X-ray diffraction. The Cu atoms in complexes 1, 2, 3, 4 and 5 are coordinated by the NOO donor set of the aroylhydrazone ligands, and one Cl or thiocyanate N atom, forming square planar coordination. The Cu atom in complex 6 is in a square pyramidal coordination, with the NOO donor set of L(1), and one N atom of bipy defining the basal plane, and with the other N atom of bipy occupying the apical position. Complexes 1, 2, 3, 4 and 5 show effective urease inhibitory activities, with IC50 values of 5.14, 0.20, 4.06, 5.52 and 0.26μM, respectively. Complex 6 has very weak activity against urease, with IC50 value over 100μM. Molecular docking study of the complexes with the Helicobacter pylori urease was performed. The relationship between structures and urease inhibitory activities indicated that copper complexes with square planar coordination are better models for urease inhibition. Copyright © 2016 Elsevier Inc. All rights reserved.

Lanthanide (III) complexes of 2-(N-salicylideneamino)-4-phenylthiazole

International Nuclear Information System (INIS)

Sasidharan, G.N.; Mohanan, K.; Lakshmi Prabha, A.N.

2002-01-01

Lanthanide(III) complexes of 2-(N-salicylideneamino)-4- phenylthiazole (HSAT) have been synthesised and characterised by elemental, analytical, thermogravimetric, molar conductance, UV- visible, IR and NMR spectral data. The ligand coordinates to the lanthanide(III) ion in a tridentate fashion without deprotonation, giving complexes of the type [Ln(HSAT) 2 (NO 3 ) 3 ] and [Ln(HSAT) 2 (H 2 0) 3 Cl 3 ]. The spectral data reveal that the ligand is bonded to the lanthanide ion through azomethine nitrogen, ring nitrogen and phenolic oxygen without deprotonation. The nitrate group acts in a bidentate fashion. The ligand and the metal complexes exhibit antibacterial and antifungal activities. (author)

Utilization of mixed ligands to construct diverse Ni(II)-coordination polymers based on terphenyl-2,2′,4,4′-tetracarboxylic acid and varied N-donor co-ligands

Energy Technology Data Exchange (ETDEWEB)

Wang, Chao [College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, Hubei Provincial Collaborative Innovation Center for New Energy Microgrid, China Three Gorges University, Yichang 443002 (China); Zhao, Jun, E-mail: junzhao08@126.com [College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, Hubei Provincial Collaborative Innovation Center for New Energy Microgrid, China Three Gorges University, Yichang 443002 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 35002 (China); Xia, Liang [College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, Hubei Provincial Collaborative Innovation Center for New Energy Microgrid, China Three Gorges University, Yichang 443002 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 35002 (China); Wu, Xue-Qian; Wang, Jian-Fang; Dong, Wen-Wen; Wu, Ya-Pan [College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, Hubei Provincial Collaborative Innovation Center for New Energy Microgrid, China Three Gorges University, Yichang 443002 (China)

2016-06-15

Three new coordination polymers, namely, {[Ni(H_2L)(bix)(H_2O)_2]·2h_2O}{sub n} (1), {[Ni(HL)(Hdpa)(H_2O)_2]·H_2O}{sub n} (2), {[Ni(L)_0_._5(bpp)(H_2O)]·H_2O}{sub n} (3) (H{sub 4}L=terphenyl-2,2′,4,4′-tetracarboxylic acid; bix=1,4-bis(imidazol-1-ylmethyl)benzene; dpa =4,4′-dipyridylamine; bpp=1,3-bis(4-pyridyl)propane), based on rigid H{sub 4}L ligand and different N-donor co-ligands, have been synthesized under hydrothermal conditions. Compound 1 features a 3D 4-connected 6{sup 6}-dia-type framework with H{sub 4}L ligand adopts a μ{sub 2}-bridging mode with two symmetry-related carboxylate groups in μ{sub 1}-η{sup 1}:η{sup 0} monodentate mode. Compound 2 displays a 1D [Ni(HL)(Hdpa)]{sub n} ribbon chains motif, in which the H{sub 4}L ligand adopts a μ{sub 2}-bridging mode with two carboxylate groups in μ{sub 1}-η{sup 1}:η{sup 1} and μ{sub 1}-η{sup 1}:η{sup 0} monodentate modes, while 3 possesses a (4,4)-connected 3D frameworks with bbf topology, with H{sub 4}L ligand displays a μ{sub 4}-bridging coordination mode. The H{sub 4}L ligand displays not only different deprotonated forms but also diverse coordination modes and conformations. The structural diversities among 1–3 have been carefully discussed, and the roles of N-donor co-ligands in the self-assembly of coordination polymers have been well documented. - Graphical abstract: Three nickel coordination polymers with different architectures based on mixed ligand system were synthesized and structurally characterized. Topology analyses indicate that 1 shows the 4-connected 6{sup 6}-dia net, 1D ribbon chains for 2 and 3D (4,4)-connected bbf network for 3. Display Omitted - Highlights: • Three Ni-based coordination polymers with distinct features have been prepared. • Compound 1 features a 3D 4-connected 66-dia-type framework, 2 displays a 1D [Ni(HL)(Hdpa)]{sub n} ribbon chains motif, while 3 possesses a (4,4)-connected 3D frameworks with bbf topology. • The “mixed ligand assembled�

Determination of formal redox potentials in aqueous solution of copper(II) complexes with ligands having nitrogen and oxygen donor atoms and comparison with their EPR and UV-Vis spectral features.

Science.gov (United States)

Tabbì, Giovanni; Giuffrida, Alessandro; Bonomo, Raffaele P

2013-11-01

Formal redox potentials in aqueous solution were determined for copper(II) complexes with ligands having oxygen and nitrogen as donor atoms. All the chosen copper(II) complexes have well-known stereochemistries (pseudo-octahedral, square planar, square-based pyramidal, trigonal bipyramidal or tetrahedral) as witnessed by their reported spectroscopic, EPR and UV-visible (UV-Vis) features, so that a rough correlation between the measured redox potential and the typical geometrical arrangement of the copper(II) complex could be established. Negative values have been obtained for copper(II) complexes in tetragonally elongated pseudo-octahedral geometries, when measured against Ag/AgCl reference electrode. Copper(II) complexes in tetrahedral environments (or flattened tetrahedral geometries) show positive redox potential values. There is a region, always in the field of negative redox potentials which groups the copper(II) complexes exhibiting square-based pyramidal arrangements. Therefore, it is suggested that a measurement of the formal redox potential could be of great help, when some ambiguities might appear in the interpretation of spectroscopic (EPR and UV-Vis) data. Unfortunately, when the comparison is made between copper(II) complexes in square-based pyramidal geometries and those in square planar environments (or a pseudo-octahedral) a little perturbed by an equatorial tetrahedral distortion, their redox potentials could fall in the same intermediate region. In this case spectroscopic data have to be handled with great care in order to have an answer about a copper complex geometrical characteristics. © 2013.

Cobalt(II) complexes with azole-pyridine type ligands for non-aqueous redox-flow batteries: Tunable electrochemistry via structural modification

Science.gov (United States)

Armstrong, Craig G.; Toghill, Kathryn E.

2017-05-01

A single species redox flow battery employing a new class of cobalt(II) complexes with 'tunable' tridentate azole-pyridine type ligands is reported. Four structures were synthesised and their electrochemical, physical and battery characteristics were investigated as a function of successive substitution of the ligand terminal pyridyl donors. The Co(II/I) and Co(III/II) couples are stable and quasi-reversible on gold and glassy carbon electrodes, however redox potentials are tunable allowing the cobalt potential difference to be preferentially increased from 1.07 to 1.91 V via pyridine substitution with weaker σ-donating/π-accepting 3,5-dimethylpyrazole groups. The charge-discharge properties of the system were evaluated using an H-type glass cell and graphite rod electrodes. The complexes delivered high Coulombic efficiencies of 89.7-99.8% and very good voltaic efficiencies of 70.3-81.0%. Consequently, energy efficiencies are high at 63.1-80.8%, marking an improvement on other similar non-aqueous systems. Modification of the ligands also improved solubility from 0.18 M to 0.50 M via pyridyl substitution with 3,5-dimethylpyrazole, though the low solubility of the complexes limits the overall energy capacity to between 2.58 and 12.80 W h L-1. Preliminary flow cell studies in a prototype flow cell are also demonstrated.

Ligand field effects in the nuclear magnetic shielding of nitrogen-15 and cobalt-59 in bent nitrosyl complexes of cobalt(III)

International Nuclear Information System (INIS)

Duffin, P.A.; Larkworthy, L.F.; Mason, J.; Stephens, A.N.; Thompson, R.M.

1987-01-01

A range of square-pyramidal complexes of cobalt(III) with a bent apical nitrosyl ligand has been prepared and examined by 15 N and 59 Co NMR spectroscopy, in a study of nephelauxetic and spectrochemical effects at the metal and nitrogen nuclei in the bent Co-NO chromophore. The basal ligands in this comparison include dithiocarbamate, quadridentate Schiff base or porphine, and bis-chelating diamine or oximate, so as to give S 4 , S 2 N 2 , N 4 , OONN, or ONON coordination in the plane and a range of substituents in the chelate and phenylene rings. The shielding of both cobalt and nitrogen tends to decrease with decrease in the M(d) → π*(NO) back-bonding, as indicated by the MN and NO bond distances, the MNO angle and the NO stretching frequency. The shieldings decrease from sulfur to nitrogen to oxygen coligators and also with electron withdrawal by ring substituents (and vice versa), i.e. with decrease in the ligand field splitting and in the nephelauxetism of the coligands. These parallelisms of the cobalt and nitrogen shielding accord with the orbital theory that was developed to explain the bending of the MNO ligand and influences of the metal and coligands. Significant interdependence of spectrochemical and nephelauxetic effects at cobalt and nitrogen arises from the degree of overlap and similarity in energies of the frontier orbitals for the paramagnetic circulation at nitrogen [n(N) → π* (NO)] and at cobalt (d-d). 43 references, 5 figures, 2 tables

British nuclear non-proliferation policy and the trident purchase

International Nuclear Information System (INIS)

Keohane, D.

1984-01-01

Since the mid-1950s, the UK has had a policy of making significant and sustained efforts to minimise the spread of nuclear arms. Unlike the global focus of its non-proliferation policy, the decision on Trident in centred upon national and perhaps regional requirements. At a time when non-nuclear countries are charging nuclear-weapon states with a grave failure to meet their obligations under Article VI of the NPT, Britain is making plans that would further increase the gap between the nuclear 'haves' and have-nots' and that indicate it expects to require nuclear arms in the next century. It would of course be unrealistic to expect a government to fully harmonise its manifold policies and unreasonable to suggest it should give absolute priority to one of its policy concerns, such as non-proliferation. But Britain is emphasising the high value it places upon the independent possession of strategic nuclear arms through its decision to purchase Trident, thus implicitly contradicting the logic underlying its non-proliferation policy. Compared to other factors, the influence of the Trident decision upon the non-proliferation regime appears very marginal, yet it is unlikely to strengthen that regime

Strong metal-metal coupling in mixed-valent intermediates [Cl(L)Ru(mu-tppz)Ru(L)Cl](+), L = beta-diketonato ligands, tppz=2,3,5,6-tetrakis(2-pyridyl)pyrazine

Czech Academy of Sciences Publication Activity Database

Kundu, T.; Schweinfurth, D.; Sarkar, B.; Mondal, T. K.; Fiedler, Jan; Mobin, S. M.; Puranik, V. G.; Kaim, W.; Lahiri, G. K.

2012-01-01

Roč. 41, č. 43 (2012), s. 13429-13440 ISSN 1477-9226 R&D Projects: GA AV ČR IAA400400802 Institutional support: RVO:61388955 Keywords : TRIDENTATE BRIDGING LIGAND * DENSITY-FUNCTIONAL THEORY * HYDRAZONE-BASED LIGAND S Subject RIV: CG - Electrochemistry Impact factor: 3.806, year: 2012

Synthesis and Characterization of a Triphos Ligand Derivative and the Corresponding Pd ^II Complexes: Triphos Ligand Derivative and Corresponding Pd ^II Complexes

Energy Technology Data Exchange (ETDEWEB)

Miller, Deanna L.; Boro, Brian J.; Grubel, Katarzyna; Helm, Monte L.; Appel, Aaron M.

2015-11-16

The synthesis of the new bis(2-(diphenylphosphino)ethyl)methylhydroxyphosphine tridentate phosphine ligand, LCH2OH/Ph, is reported. The ligand reacts with [Pd(Cl)2(PhCN)2 to form [Pd(LCH2OH/Ph)Cl]Cl. Exchange of the chloride ions for triflate (OTf–) using AgOTf yielded pure [Pd(LCH2OH/Ph)OTf]OTf. In addition to spectral characterization the free ligand, LCH2OH/Ph, and Pd(II) complex, [Pd(LCH2OH/Ph)OTf]OTf, are structurally characterized. This research was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated by Battelle for DOE.

Studies on coordination chemistry and bioactivity of some nitrogen-sulfur donor ligands with some heavy metal ions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Zakaria, C.M.; Wan bin Abdullah; Grouse, Karen A.; Ali, A.M.; Yamin, B.M.; Fun, H.-K.

2003-08-01

A bidentate NS ligand, hydraziniumdithiocarbazate (HzDTC), was prepared. The reaction of HzDTC with benzoin (HzDTCl) yielded a new Schiff base. Some complexes of cadmium(II), tin(II) and antimony(III) containing HzDTC and S-picolyldithiocarbazate (SPDTC) were prepared and characterized by a variety of physico-chemical techniques. The structure of the Schiff base, bis(methylphenyl)methylene (N-phenylmethylene-N'-phenylmethine)hydrazine, was solved by X-ray crystallography. The HzDTC and SPDTC behaved as uninegatively charged bidentate ligands. The antibacterial and anti-fungal properties of ligands and their metal complexes were evaluated against four pathogenic bacteria and fungi. HzDTC was very effective against all the microbes while the complexes of HzDTC were antibacterial. The complexes of SPDTC were effective against fungi. [Cd(HzDTC)Br. H 2 O], in particular, was moderately active against CEM-SS (human cell T-lymphoblastic leukemia) cells. (author)

AutoSite: an automated approach for pseudo-ligands prediction—from ligand-binding sites identification to predicting key ligand atoms

Science.gov (United States)

Ravindranath, Pradeep Anand; Sanner, Michel F.

2016-01-01

Motivation: The identification of ligand-binding sites from a protein structure facilitates computational drug design and optimization, and protein function assignment. We introduce AutoSite: an efficient software tool for identifying ligand-binding sites and predicting pseudo ligand corresponding to each binding site identified. Binding sites are reported as clusters of 3D points called fills in which every point is labelled as hydrophobic or as hydrogen bond donor or acceptor. From these fills AutoSite derives feature points: a set of putative positions of hydrophobic-, and hydrogen-bond forming ligand atoms. Results: We show that AutoSite identifies ligand-binding sites with higher accuracy than other leading methods, and produces fills that better matches the ligand shape and properties, than the fills obtained with a software program with similar capabilities, AutoLigand. In addition, we demonstrate that for the Astex Diverse Set, the feature points identify 79% of hydrophobic ligand atoms, and 81% and 62% of the hydrogen acceptor and donor hydrogen ligand atoms interacting with the receptor, and predict 81.2% of water molecules mediating interactions between ligand and receptor. Finally, we illustrate potential uses of the predicted feature points in the context of lead optimization in drug discovery projects. Availability and Implementation: http://adfr.scripps.edu/AutoDockFR/autosite.html Contact: sanner@scripps.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27354702

Trident: scalable compute archives: workflows, visualization, and analysis

Science.gov (United States)

Gopu, Arvind; Hayashi, Soichi; Young, Michael D.; Kotulla, Ralf; Henschel, Robert; Harbeck, Daniel

2016-08-01

The Astronomy scientific community has embraced Big Data processing challenges, e.g. associated with time-domain astronomy, and come up with a variety of novel and efficient data processing solutions. However, data processing is only a small part of the Big Data challenge. Efficient knowledge discovery and scientific advancement in the Big Data era requires new and equally efficient tools: modern user interfaces for searching, identifying and viewing data online without direct access to the data; tracking of data provenance; searching, plotting and analyzing metadata; interactive visual analysis, especially of (time-dependent) image data; and the ability to execute pipelines on supercomputing and cloud resources with minimal user overhead or expertise even to novice computing users. The Trident project at Indiana University offers a comprehensive web and cloud-based microservice software suite that enables the straight forward deployment of highly customized Scalable Compute Archive (SCA) systems; including extensive visualization and analysis capabilities, with minimal amount of additional coding. Trident seamlessly scales up or down in terms of data volumes and computational needs, and allows feature sets within a web user interface to be quickly adapted to meet individual project requirements. Domain experts only have to provide code or business logic about handling/visualizing their domain's data products and about executing their pipelines and application work flows. Trident's microservices architecture is made up of light-weight services connected by a REST API and/or a message bus; a web interface elements are built using NodeJS, AngularJS, and HighCharts JavaScript libraries among others while backend services are written in NodeJS, PHP/Zend, and Python. The software suite currently consists of (1) a simple work flow execution framework to integrate, deploy, and execute pipelines and applications (2) a progress service to monitor work flows and sub

Preparation and configurational analysis of the stereoisomers of β,γ-bidentate Rh(H2O)4ATP and α,β,γ-tridentate Rh(H2O)3ATP. A new class of enzyme active site probes

International Nuclear Information System (INIS)

Lu, Z.; Shorter, A.L.; Lin, I.; Dunaway-Mariano, D.

1988-01-01

Exchange-inert Co(III) and Cr(III) complexes of polyphosphates have proved to be useful probes of the structural and biochemical properties of naturally occurring Mg II (polyphosphate) complexes. However, applications of these complexes are not without limitations. The Cr III (polyphosphate) probes or their enzymatic products cannot be used in NMR methods because of the paramagnetic nature of the Cr(III) metal. The redox properties of the metal in the Co III (polyphosphate) complexes require that they also be coordinated to a nitrogen-containing ligand. This requirement is not always convenient. This work reported herein was undertaken to create a new class of exchange-inert metal polyphosphate complexes that contain a metal that is both diamagnetic and redox stable. The preparation, properties, and configurational analysis of the stereoisomers of β, γ-bidentate Rh(H 2 O) 4 ATP (ATP = adenosine 5'-triphosphate) and α,β,γ-tridentate Rh(H 2 O) 3 ATP are described. 12 refs., 5 figs

Towards an interpretation of the mechanism of the actinides(III)/lanthanides(III) separation by synergistic solvent extraction with nitrogen-containing polydendate ligands

International Nuclear Information System (INIS)

Francois, N.

2000-01-01

In the field of the separation of long-lived radionuclides from the wastes produced by nuclear fuel reprocessing, aromatic nitrogen-containing polydendate ligands are potential candidates for the selective extraction, alone or in synergistic mixture with acidic extractants, of trivalent actinides from trivalent lanthanides. The first part of this work deals with the complexation of trivalent f cations with various nitrogen-containing ligands (poly-pyridine analogues). Time-resolved laser-induced fluorimetry (TRLIF) and UV-visible spectrophotometry were used to determine the nature and evaluate the stability of each complex. Among the ligands studied, the least basic Me-Btp proved to be highly selective towards americium(III) in acidic solution. In the second part, two synergistic systems (nitrogen-containing polydendate ligand and lipophilic carboxylic acid) are studied and compared in regard to the extraction and separation of lanthanides(III) and actinides(III). TRLIF and gamma spectrometry allowed the nature of the extracted complexes and the optimal conditions of efficiency of both systems to be determined. Comparison between these different studies showed that the selectivity of complexation of trivalent f cations by a given nitrogen-containing polydendate ligand could not always be linked to the Am(III)Eu(III) selectivity reached in synergistic extraction. The latter depends on the 'balance' between the acid-basic properties on the one hand, and on the hard-soft characteristics on the other hand, of both components of synergistic system. (author)

Synthesis, characterization, and reactivity of ruthenium hydride complexes of N-centered triphosphine ligands.

Science.gov (United States)

Phanopoulos, Andreas; Brown, Neil J; White, Andrew J P; Long, Nicholas J; Miller, Philip W

2014-04-07

The reactivity of the novel tridentate phosphine ligand N(CH2PCyp2)3 (N-triphos(Cyp), 2; Cyp = cyclopentyl) with various ruthenium complexes was investigated and compared that of to the less sterically bulky and less electron donating phenyl derivative N(CH2PPh2)3 (N-triphos(Ph), 1). One of these complexes was subsequently investigated for reactivity toward levulinic acid, a potentially important biorenewable feedstock. Reaction of ligands 1 and 2 with the precursors [Ru(COD)(methylallyl)2] (COD = 1,5-cycloocatadiene) and [RuH2(PPh3)4] gave the tridentate coordination complexes [Ru(tmm){N(CH2PR2)3-κ(3)P}] (R = Ph (3), Cyp (4); tmm = trimethylenemethane) and [RuH2(PPh3){N(CH2PR2)3-κ(3)P}] (R = Ph (5), Cyp (6)), respectively. Ligands 1 and 2 displayed different reactivities with [Ru3(CO)12]. Ligand 1 gave the tridentate dicarbonyl complex [Ru(CO)2{N(CH2PPh2)3-κ(3)P}] (7), while 2 gave the bidentate, tricarbonyl [Ru(CO)3{N(CH2PCyp2)3-κ(2)P}] (8). This was attributed to the greater electron-donating characteristics of 2, requiring further stabilization on coordination to the electron-rich Ru(0) center by more CO ligands. Complex 7 was activated via oxidation using AgOTf and O2, giving the Ru(II) complexes [Ru(CO)2(OTf){N(CH2PPh2)3-κ(3)P}](OTf) (9) and [Ru(CO3)(CO){N(CH2PPh2)3-κ(3)P}] (11), respectively. Hydrogenation of these complexes under hydrogen pressures of 3-15 bar gave the monohydride and dihydride complexes [RuH(CO)2{N(CH2PPh2)3-κ(3)P}] (10) and [RuH2(CO){N(CH2PPh2)3-κ(3)P}] (12), respectively. Complex 12 was found to be unreactive toward levulinic acid (LA) unless activated by reaction with NH4PF6 in acetonitrile, forming [RuH(CO)(MeCN){N(CH2PPh2)3-κ(3)P}](PF6) (13), which reacted cleanly with LA to form [Ru(CO){N(CH2PPh2)3-κ(3)P}{CH3CO(CH2)2CO2H-κ(2)O}](PF6) (14). Complexes 3, 5, 7, 8, 11, and 12 were characterized by single-crystal X-ray crystallography.

EPR Characterization of Dinitrosyl Iron Complexes with Thiol-Containing Ligands as an Approach to Their Identification in Biological Objects: An Overview.

Science.gov (United States)

Vanin, Anatoly F

2018-06-01

The overview demonstrates how the use of only one physico-chemical approach, viz., the electron paramagnetic resonance method, allowed detection and identification of dinitrosyl iron complexes with thiol-containing ligands in various animal and bacterial cells. These complexes are formed in biological objects in the paramagnetic (electron paramagnetic resonance-active) mononuclear and diamagnetic (electron paramagnetic resonance-silent) binuclear forms and control the activity of nitrogen monoxide, one of the most universal regulators of metabolic processes in the organism. The analysis of electronic and spatial structures of dinitrosyl iron complex sheds additional light on the mechanism whereby dinitrosyl iron complex with thiol-containing ligands function in human and animal cells as donors of nitrogen monoxide and its ionized form, viz., nitrosonium ions (NO + ).

Oxovanadium (iv) complexes with n/o- and o-donor ligands: their synthesis, characterization, semiempirical study and alkaline phosphatase activity (abstract)

International Nuclear Information System (INIS)

Munawar, K.S.; Ali, S.; Khan, A.N.

2011-01-01

Various N/O- and O-donor ligands and their oxovanadium complexes have been synthesized and characterized by different techniques such as FTIR, elemental analysis, thermogravimetery and conductometry. The IR data show the bidentate nature of the ligands and reveals hexa-coordinated geometry in the solid state which is also confirmed by semi-empirical study. Conductance measurements reveal the non-electrolytic nature of the complexes. These complexes have been checked for their alkaline phosphatase activity in the presence and absence of inhibitor which shows that by the addition of inhibitor the activity of enzyme decreases and at higher concentration it is completely inhibited. (author)

Kinetic and theoretical studies on the protonation of [Ni(2-SC6H4N){PhP(CH2CH2PPh2)2}]+: nitrogen versus sulfur as the protonation site.

Science.gov (United States)

Petrou, Athinoula L; Koutselos, Andreas D; Wahab, Hilal S; Clegg, William; Harrington, Ross W; Henderson, Richard A

2011-02-07

The complexes [Ni(4-Spy)(triphos)]BPh(4) and [Ni(2-Spy)(triphos)]BPh(4) {triphos = PhP(CH(2)CH(2)PPh(2))(2), 4-Spy = 4-pyridinethiolate, 2-Spy = 2-pyridinethiolate} have been prepared and characterized both spectroscopically and using X-ray crystallography. In both complexes the triphos is a tridentate ligand. However, [Ni(4-Spy)(triphos)](+) comprises a 4-coordinate, square-planar nickel with the 4-Spy ligand bound to the nickel through the sulfur while [Ni(2-Spy)(triphos)](+) contains a 5-coordinate, trigonal-bipyramidal nickel with a bidentate 2-Spy ligand bound to the nickel through both sulfur and nitrogen. The kinetics of the reactions of [Ni(4-Spy)(triphos)](+) and [Ni(2-Spy)(triphos)](+) with lutH(+) (lut = 2,6-dimethylpyridine) in MeCN have been studied using stopped-flow spectrophotometry, and the two complexes show very different reactivities. The reaction of [Ni(4-Spy)(triphos)](+) with lutH(+) is complete within the deadtime of the stopped-flow apparatus (2 ms) and corresponds to protonation of the nitrogen. However, upon mixing [Ni(2-Spy)(triphos)](+) and lutH(+) a reaction is observed (on the seconds time scale) to produce an equilibrium mixture. The mechanistic interpretation of the rate law has been aided by the application of MSINDO semiempirical and ADF calculations. The kinetics and calculations are consistent with the reaction between [Ni(2-Spy)(triphos)](+) and lutH(+) involving initial protonation of the sulfur followed by dissociation of the nitrogen and subsequent transfer of the proton from sulfur to nitrogen. The factors affecting the position of protonation and the coupling of the coordination state of the 2-pyridinethiolate ligand to the site of protonation are discussed.

Cyclometalation and coupling of a rigid 4,5-bis(imino)acridanide pincer ligand on yttrium.

Science.gov (United States)

Wong, Edwin W Y; Emslie, David J H

2015-07-07

An extremely rigid NNN-donor proligand, 4,5-bis{(diphenylmethylene)amino}-2,7,9,9-tetramethylacridan, H[AIm2] was prepared in five steps starting from 5-methyl-2-aminobenzoic acid and 4-bromotoluene. Reaction of intensely orange H[AIm2] with LiCH2SiMe3 formed deep blue Li(x)[AIm2]x (x = 2 in the solid state), while reaction with [Y(CH2SiMe3)3(THF)2] (0.5 equiv.) afforded deep blue [Y(AIm2)(AIm)] (1; AIm = an AIm2 ligand cyclometalated at the ortho-position of one of the phenyl rings). Compound 1 slowly isomerizes to form green-brown 2, which contains a single trianionic, hexadentate ligand that features one amine, two imine, and three amido donors. The acridanide backbone and one imine group in each of the original AIm2 ligands is intact, but the two acridanide backbones are now linked by an isoindoline heterocycle. Yttrium in 2 is coordinated to six nitrogen donors and the ortho carbon of an isoindoline phenyl substituent. The intense colours of H[AIm2], Li(x)[AIm2]x and 1 were shown by TD-DFT calculations to arise from charge transfer transitions from the HOMO, which is localized on the acridanide ligand backbone, to the LUMO and LUMO+1, which are localized on the imine substituents. The conversion of 1 to 2 was studied by UV-Visible absorption spectroscopy and is first-order with a half-life of 7.8 hours at room temperature.

Formation constants of Sm(III), Dy(III), Gd(III), Pr(III) and Nd(III) complexes of tridentate schiff base, 2-[(1H-benzimidazol-2-yl-methylene) amino] phenol

International Nuclear Information System (INIS)

Omprakash, K.L.; Chandra Pal, A.V.; Reddy, M.L.N.

1982-01-01

A new tridentate schiff base, 2- (1H-benzimidazol-2-yl-methylene)amino phenol derived from benzimididazole-2-carbo-xaldehyde and 2-aminophenol has been synthesised and characterised by spectral and analytical data. Proton-ligand formation constants of the schiff base and metal-ligand formation constants of its complexes with Sm(III), Dy(III), Gd(III), Nd(III) and Pr(III) have been determined potentiometrically in 50% (v/v) aqueous dioxane at an ionic strength of 0.1M (NaClO 4 ) and at 25deg C using the Irving-Rossotti titration technique. The order of stability constants (logβ 2 ) is found to be Sm(III)>Dy(III)>Gd(III)>Pr(III)>Nd(III). (author)

Formation constants of Sm(III), Dy(III), Gd(III), Pr(III) and Nd(III) complexes of tridentate schiff base, 2-((1H-benzimidazol-2-yl-methylene) amino) phenol

Energy Technology Data Exchange (ETDEWEB)

Omprakash, K L; Chandra Pal, A V; Reddy, M L.N. [Osmania Univ., Hyderabad (India). Dept. of Chemistry

1982-03-01

A new tridentate schiff base, 2- (1H-benzimidazol-2-yl-methylene)amino phenol derived from benzimididazole-2-carbo-xaldehyde and 2-aminophenol has been synthesised and characterised by spectral and analytical data. Proton-ligand formation constants of the schiff base and metal-ligand formation constants of its complexes with Sm(III), Dy(III), Gd(III), Nd(III) and Pr(III) have been determined potentiometrically in 50% (v/v) aqueous dioxane at an ionic strength of 0.1M (NaClO/sub 4/) and at 25deg C using the Irving-Rossotti titration technique. The order of stability constants (log..beta../sub 2/) is found to be Sm(III)>Dy(III)>Gd(III)>Pr(III)>Nd(III).

Ab initio and density functional theoretical design and screening of model crown ether based ligand (host) for extraction of lithium metal ion (guest): effect of donor and electronic induction.

Science.gov (United States)

Boda, Anil; Ali, Sk Musharaf; Rao, Hanmanth; Ghosh, Sandip K

2012-08-01

The structures, energetic and thermodynamic parameters of model crown ethers with different donor, cavity and electron donating/ withdrawing functional group have been determined with ab initio MP2 and density functional theory in gas and solvent phase. The calculated values of binding energy/ enthalpy for lithium ion complexation are marginally higher for hard donor based aza and oxa crown compared to soft donor based thia and phospha crown. The calculated values of binding enthalpy for lithium metal ion with 12C4 at MP2 level of theory is in good agreement with the available experimental result. The binding energy is altered due to the inductive effect imparted by the electron donating/ withdrawing group in crown ether, which is well correlated with the values of electron transfer. The role of entropy for extraction of hydrated lithium metal ion by different donor and functional group based ligand has been demonstrated. The HOMO-LUMO gap is decreased and dipole moment of the ligand is increased from gas phase to organic phase because of the dielectric constant of the solvent. The gas phase binding energy is reduced in solvent phase as the solvent molecules weaken the metal-ligand binding. The theoretical values of extraction energy for LiCl salt from aqueous solution in different organic solvent is validated by the experimental trend. The study presented here should contribute to the design of model host ligand and screening of solvent for metal ion recognition and thus can contribute in planning the experiments.

Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants.

Science.gov (United States)

Grimes, Travis S; Heathman, Colt R; Jansone-Popova, Santa; Ivanov, Alexander S; Roy, Santanu; Bryantsev, Vyacheslav S; Zalupski, Peter R

2018-02-05

The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am 3+ , Cm 3+ , and Ln 3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL (aq) complexes at the same aqueous acidity. The denticity change observed for Eu 3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL (aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am 3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am 3+ , Cm 3+ ) and trivalent lanthanide chelates (La 3+ -Lu 3+ ) are observed in liquid-liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by

Final Technical Report [Development of Catalytic Alkylation and Fluoroalkylation Methods

Energy Technology Data Exchange (ETDEWEB)

Vicic, David A.

2014-05-01

In the early stages of this DOE-funded research project, we sought to prepare and study a well-defined nickel-alkyl complex containing tridentate nitrogen donor ligands. We found that reaction of (TMEDA)NiMe2 (1) with terpyridine ligand cleanly led to the formation of (terpyridyl)NiMe (2), which we also determined to be an active alkylation catalyst. The thermal stability of 2 was unlike that seen for any of the active pybox ligands, and enabled a number of key studies on alkyl transfer reactions to be performed, providing new insights into the mechanism of nickel-mediated alkyl-alkyl cross-coupling reactions. In addition to the mechanistic studies, we showed that the terpyridyl nickel compounds can catalytically cross-couple alkyl iodides in yields up to 98% and bromides in yields up to 46 %. The yields for the bromides can be increased up to 67 % when the new palladium catalyst [(tpy’)Pd-Ph]I is used. The best route to the targeted [(tpy)NiBr] (1) was found to involve the comproportionation reaction of [(dme)NiBr{sub 2}] and [Ni(COD){sub 2}] in the presence of two equivalents of terpyridine. This reaction was driven to high yields of product formation (72 % isolated) by the precipitation of 1 from THF solvent.

Aqua[N-phenyl-2-(quinolin-8-yloxyacetamide]dinitratozinc(II

Directory of Open Access Journals (Sweden)

Qiu-Fen Wang

2010-03-01

Full Text Available In the title complex, [Zn(NO32(C17H14N2O2(H2O], the six-coordinated Zn atom is in a distorted octahedral geometry, the donor centers being two O atoms and one N atom from the tridentate organic ligand, a water O atom and two O atoms from two monodentate nitrate ions. In the crystal, O—H...O hydrogen bonds between the coordinated water molecules and nitrate O atoms and N—H...O hydrogen bonds between the main ligand and nitrate O atoms consolidate the three-dimensional network.

Ammonia formation by metal-ligand cooperative hydrogenolysis of a nitrido ligand

Science.gov (United States)

Askevold, Bjorn; Nieto, Jorge Torres; Tussupbayev, Samat; Diefenbach, Martin; Herdtweck, Eberhardt; Holthausen, Max C.; Schneider, Sven

2011-07-01

Bioinspired hydrogenation of N2 to ammonia at ambient conditions by stepwise nitrogen protonation/reduction with metal complexes in solution has experienced remarkable progress. In contrast, the highly desirable direct hydrogenation with H2 remains difficult. In analogy to the heterogeneously catalysed Haber-Bosch process, such a reaction is conceivable via metal-centred N2 splitting and unprecedented hydrogenolysis of the nitrido ligands to ammonia. We report the synthesis of a ruthenium(IV) nitrido complex. The high nucleophilicity of the nitrido ligand is demonstrated by unusual N-C coupling with π-acidic CO. Furthermore, the terminal nitrido ligand undergoes facile hydrogenolysis with H2 at ambient conditions to produce ammonia in high yield. Kinetic and quantum chemical examinations of this reaction suggest cooperative behaviour of a phosphorus-nitrogen-phosphorus pincer ligand in rate-determining heterolytic hydrogen splitting.

Modeling the Syn-Disposition of Nitrogen Donors in Non-Heme Diiron Enzymes. Synthesis, Characterization, and Hydrogen Peroxide Reactivity of Diiron(III) Complexes with the Syn N-Donor Ligand H2BPG2DEV

Science.gov (United States)

Friedle, Simone; Kodanko, Jeremy J.; Morys, Anna J.; Hayashi, Takahiro; Moënne-Loccoz, Pierre; Lippard, Stephen J.

2009-01-01

In order to model the syn disposition of histidine residues in carboxylate-bridged non-heme diiron enzymes, we prepared a new dinucleating ligand, H2BPG2DEV, that provides this geometric feature. The ligand incorporates biologically relevant carboxylate functionalities, which have not been explored as extensively as nitrogen-only analogs. Three novel oxo-bridged diiron(III) complexes [Fe2(μ-O)(H2O)2-(BPG2DEV)](ClO4)2 (6), [Fe2(μ-O)(μ-O CAriPrO)(BPG2DEV)](ClO4) (7), and [Fe2(μ-O)(μ-CO3)(BPG2DEV)] (8) were prepared. Single crystal X-ray structural characterization confirms that two pyridines are bound syn with respect to the Fe–Fe vector in these compounds. The carbonato-bridged complex 8 forms quantitatively from 6 in a rapid reaction with gaseous CO2 in organic solvents. A common maroon-colored intermediate (λmax = 490 nm; ε = 1500 M−1 cm−1) forms in reactions of 6, 7, or 8 with H2O2 and NEt3 in CH3CN/H2O solutions. Mass spectrometric analyses of this species, formed using 18O-labeled H2O2, indicate the presence of a peroxide ligand bound to the oxo-bridged diiron(III) center. The Mössbauer spectrum at 90 K of the EPR-silent intermediate exhibits a quadrupole doublet with δ. = 0.58 mm/s and ΔEQ = 0.58 mm/s. The isomer shift is typical for a peroxodiiron(III) species, but the quadrupole splitting parameter is unusually small compared to related complexes. These Mössbauer parameters are comparable to those observed for a peroxo intermediate formed in the reaction of reduced toluene/o-xylene monooxygenase hydroxylase (ToMOH) with dioxygen. Resonance Raman studies reveal an unusually low-energy O–O stretching mode in the peroxo intermediate that is consistent with a short diiron distance. Although peroxodiiron(III) intermediates generated from 6, 7, and 8 are poor O-atom transfer catalysts, they display highly efficient catalase activity, with turnover numbers up to 10,000. In contrast to hydrogen peroxide reactions of diiron(III) complexes that lack

Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants

Energy Technology Data Exchange (ETDEWEB)

Grimes, Travis S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heathman, Colt R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jansone-Popova, Santa [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Alexander S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roy, Santanu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryantsev, Vyacheslav S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zalupski, Peter R. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2018-01-05

Here, the novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N",N"-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N",N"-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am³⁺, Cm³⁺, and Ln³⁺ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL_(aq) complexes at the same aqueous acidity. The denticity change observed for Eu³⁺ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL_(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am³⁺ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am³⁺, Cm³⁺) and trivalent lanthanide chelates (La³⁺–Lu³⁺) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA

Synthesis and characterization of some metal complexes of a Schiff base derived from ninhydrin and α,L-alanine

Directory of Open Access Journals (Sweden)

Mehabaw Getahun Derebe

2002-06-01

Full Text Available Complexes of Mn(II, Fe(III, Co(II, Ni(II and Zn(II with an intermediate Schiff base derived from ninhydrin and α,L-alanine (indane-1,3-dione-2-imine-N-2-propionate, IDIP were successfully synthesized. All complexes were distinctly colored and were characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectral studies. The ligand (Schiff base was shown to behave as a monobasic tridentate ONO donor. The Mn(II and Fe(III complexes contain only one ligand molecule plus water and chloride(s per metal ion, while all the others contain two ligand molecules per metal ion. An octahedral geometry is proposed for the metal complexes.

CO2 activation through silylimido and silylamido zirconium hydrides supported on N-donor chelating SBA15 surface ligand

KAUST Repository

Pasha, Fahran Ahmad

2016-01-04

Density functional theory calculations and 2D 1H-13C HETCOR solid state NMR spectroscopy prove that CO2 can probe, by its own reactivity, different types of N-donor surface ligands on SBA15-supported ZrIV hydrides: [(≡Si-O-)(≡Si-N=)[Zr]H] and [(≡Si-NH-)(≡Si-X-)[Zr]H2] (X = O or NH). Moreover, [(≡Si-O-)(≡Si-N=)[Zr]H] activates CO2 more efficiently than the other complexes and leads to a carbimato Zr formate.

Trident: A Universal Tool for Generating Synthetic Absorption Spectra from Astrophysical Simulations

Energy Technology Data Exchange (ETDEWEB)

Hummels, Cameron B. [TAPIR, California Institute of Technology, Pasadena, CA 91125 (United States); Smith, Britton D. [San Diego Supercomputer Center, University of California, San Diego, CA 92121 (United States); Silvia, Devin W. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2017-09-20

Hydrodynamical simulations are increasingly able to accurately model physical systems on stellar, galactic, and cosmological scales; however, the utility of these simulations is often limited by our ability to directly compare them with the data sets produced by observers: spectra, photometry, etc. To address this problem, we have created trident, a Python-based open-source tool for post-processing hydrodynamical simulations to produce synthetic absorption spectra and related data. trident can (i) create absorption-line spectra for any trajectory through a simulated data set mimicking both background quasar and down-the-barrel configurations; (ii) reproduce the spectral characteristics of common instruments like the Cosmic Origins Spectrograph; (iii) operate across the ultraviolet, optical, and infrared using customizable absorption-line lists; (iv) trace simulated physical structures directly to spectral features; (v) approximate the presence of ion species absent from the simulation outputs; (vi) generate column density maps for any ion; and (vii) provide support for all major astrophysical hydrodynamical codes. trident was originally developed to aid in the interpretation of observations of the circumgalactic medium and intergalactic medium, but it remains a general tool applicable in other contexts.

Trident: A Universal Tool for Generating Synthetic Absorption Spectra from Astrophysical Simulations

Science.gov (United States)

Hummels, Cameron B.; Smith, Britton D.; Silvia, Devin W.

2017-09-01

Hydrodynamical simulations are increasingly able to accurately model physical systems on stellar, galactic, and cosmological scales; however, the utility of these simulations is often limited by our ability to directly compare them with the data sets produced by observers: spectra, photometry, etc. To address this problem, we have created trident, a Python-based open-source tool for post-processing hydrodynamical simulations to produce synthetic absorption spectra and related data. trident can (I) create absorption-line spectra for any trajectory through a simulated data set mimicking both background quasar and down-the-barrel configurations; (II) reproduce the spectral characteristics of common instruments like the Cosmic Origins Spectrograph; (III) operate across the ultraviolet, optical, and infrared using customizable absorption-line lists; (IV) trace simulated physical structures directly to spectral features; (v) approximate the presence of ion species absent from the simulation outputs; (VI) generate column density maps for any ion; and (vii) provide support for all major astrophysical hydrodynamical codes. trident was originally developed to aid in the interpretation of observations of the circumgalactic medium and intergalactic medium, but it remains a general tool applicable in other contexts.

Trident: A Universal Tool for Generating Synthetic Absorption Spectra from Astrophysical Simulations

International Nuclear Information System (INIS)

Hummels, Cameron B.; Smith, Britton D.; Silvia, Devin W.

2017-01-01

Hydrodynamical simulations are increasingly able to accurately model physical systems on stellar, galactic, and cosmological scales; however, the utility of these simulations is often limited by our ability to directly compare them with the data sets produced by observers: spectra, photometry, etc. To address this problem, we have created trident, a Python-based open-source tool for post-processing hydrodynamical simulations to produce synthetic absorption spectra and related data. trident can (i) create absorption-line spectra for any trajectory through a simulated data set mimicking both background quasar and down-the-barrel configurations; (ii) reproduce the spectral characteristics of common instruments like the Cosmic Origins Spectrograph; (iii) operate across the ultraviolet, optical, and infrared using customizable absorption-line lists; (iv) trace simulated physical structures directly to spectral features; (v) approximate the presence of ion species absent from the simulation outputs; (vi) generate column density maps for any ion; and (vii) provide support for all major astrophysical hydrodynamical codes. trident was originally developed to aid in the interpretation of observations of the circumgalactic medium and intergalactic medium, but it remains a general tool applicable in other contexts.

Synthesis and Structural Studies on Transition Metal Complexes Derived from 4-Hydroxy-4-methyl–2-pentanone-1H-benzimidazol-2-yl-hydrazone

Directory of Open Access Journals (Sweden)

M. Neelamma

2011-01-01

Full Text Available Transition metal complexes of Cr(III, Fe(III, Mn(II, Co(II, Ni(II, Cu(II and Zn(II with a tridentate ligand, 4-hydroxy-4-methyl-2-pentanone-1H-benzimidazole-2yl-hydrazone (H-HPBH derived from the condensation of 2-hydrazinobenzimidazole and diacetone alcohol was synthesized. Characterization has been done on the basis of analytical, conductance, thermal and magnetic data, infrared, 1H NMR, electronic, mass and ESR spectral data. From analytical and thermal data, the stoichiometry of the complexes has been found to be 1:1 (metal: ligand. Divalent complexes have the general formula [M(HPBHCl(H2O2] in octahedral geometry, [M(HPBHCl] in tetrahedral and square planar stereochemistries and trivalent complexes [M(HPBHCl2(H2O] in octahedral disposition. Infrared spectral data suggest that the ligand HPBH behaves as a monobasic tridentate ligand with N: N: O donor sequence towards the metal ions. On the basis of the above physicochemical data, octahedral, tetrahedral and square planar geometries were assigned for the complexes. The ligand and metal complexes were screened for their physiological activities against E. coli and S. aureus. The order of physiological activity has been found to be Cu(II > Ni(II > Zn(II > Co(II > Cr(III > Mn(II > Fe (III > ligand against E.coli and Ni(II > Cu(II > Zn(II > Mn(II > Cr(III > Fe(III > Co(II > ligand against S. aureus.

Donor-Recipient Matching for KIR Genotypes Reduces Chronic GVHD and Missing Inhibitory KIR Ligands Protect against Relapse after Myeloablative, HLA Matched Hematopoietic Cell Transplantation.

Directory of Open Access Journals (Sweden)

Rehan Mujeeb Faridi

Full Text Available Allogeneic hematopoietic cell transplantation (HCT can be curative for many hematologic diseases. However, complications such as graft-versus-host disease (GVHD and relapse of primary malignancy remain significant and are the leading causes of morbidity and mortality. Effects of killer Ig-like receptors (KIR-influenced NK cells on HCT outcomes have been extensively pursued over the last decade. However, the relevance of the reported algorithms on HLA matched myeloablative HCT with rabbit antithymocyte globulin (ATG is used for GVHD prophylaxis remains elusive. Here we examined the role of KIR and KIR-ligands of donor-recipient pairs in modifying the outcomes of ATG conditioned HLA matched sibling and unrelated donor HCT.The study cohort consisted of 281 HLA matched sibling and unrelated donor-recipient pairs of first allogeneic marrow or blood stem cell transplantation allocated into 'discovery' (135 pairs and 'validation' (146 pairs cohorts. High resolution HLA typing was obtained from the medical charts and KIR gene repertoires were obtained by a Luminex® based SSO method. All surviving patients were followed-up for a minimum of two years. KIR and HLA class I distributions of HCT pairs were stratified as per applicable definitions and were tested for their association with cause specific outcomes [acute GVHD grade II-IV (aGVHD, chronic GVHD needing systemic therapy (cGVHD and relapse] using a multivariate competing risks regression model as well as with survival outcomes [relapse-free survival (RFS, cGVHD & relapse free survival (cGRFS and overall survival (OS] by multivariate Cox proportional hazards regression model. A significant association between KIR genotype mismatching (KIR-B/x donor into KIR-AA recipient or vice versa and cGVHD was found in both discovery (p = 0.001; SHR = 2.78; 95%CI: 1.50-5.17 and validation cohorts (p = 0.005; SHR = 2.61; 95%CI: 1.33-5.11. High incidence of cGVHD associated with KIR genotype mismatching was

Donor-Recipient Matching for KIR Genotypes Reduces Chronic GVHD and Missing Inhibitory KIR Ligands Protect against Relapse after Myeloablative, HLA Matched Hematopoietic Cell Transplantation.

Science.gov (United States)

Faridi, Rehan Mujeeb; Kemp, Taylor J; Dharmani-Khan, Poonam; Lewis, Victor; Tripathi, Gaurav; Rajalingam, Raja; Daly, Andrew; Berka, Noureddine; Storek, Jan; Masood Khan, Faisal

2016-01-01

Allogeneic hematopoietic cell transplantation (HCT) can be curative for many hematologic diseases. However, complications such as graft-versus-host disease (GVHD) and relapse of primary malignancy remain significant and are the leading causes of morbidity and mortality. Effects of killer Ig-like receptors (KIR)-influenced NK cells on HCT outcomes have been extensively pursued over the last decade. However, the relevance of the reported algorithms on HLA matched myeloablative HCT with rabbit antithymocyte globulin (ATG) is used for GVHD prophylaxis remains elusive. Here we examined the role of KIR and KIR-ligands of donor-recipient pairs in modifying the outcomes of ATG conditioned HLA matched sibling and unrelated donor HCT. The study cohort consisted of 281 HLA matched sibling and unrelated donor-recipient pairs of first allogeneic marrow or blood stem cell transplantation allocated into 'discovery' (135 pairs) and 'validation' (146 pairs) cohorts. High resolution HLA typing was obtained from the medical charts and KIR gene repertoires were obtained by a Luminex® based SSO method. All surviving patients were followed-up for a minimum of two years. KIR and HLA class I distributions of HCT pairs were stratified as per applicable definitions and were tested for their association with cause specific outcomes [acute GVHD grade II-IV (aGVHD), chronic GVHD needing systemic therapy (cGVHD) and relapse] using a multivariate competing risks regression model as well as with survival outcomes [relapse-free survival (RFS), cGVHD & relapse free survival (cGRFS) and overall survival (OS)] by multivariate Cox proportional hazards regression model. A significant association between KIR genotype mismatching (KIR-B/x donor into KIR-AA recipient or vice versa) and cGVHD was found in both discovery (p = 0.001; SHR = 2.78; 95%CI: 1.50-5.17) and validation cohorts (p = 0.005; SHR = 2.61; 95%CI: 1.33-5.11). High incidence of cGVHD associated with KIR genotype mismatching was applicable

A tetrapositive metal ion in the gas phase: Thorium(IV) coordinated by neutral tridentate ligands

International Nuclear Information System (INIS)

Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K.; Hu, Han-Shi; Li, Jun

2013-01-01

Sheltering thorium ions: A Th 4+ ion supported by three neutral tetramethyl-3-oxaglutaramide ligands (L=TMOGA) is produced in the gas phase by electrospray ionization. The thorium in chiral Th(L) 3 4+ is coordinated by nine oxygen atoms. Quantum chemical studies revealed a decrease in Th-O binding energies and bond orders and an increase in bond lengths, as the number of coordinating ligands increases. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A tetrapositive metal ion in the gas phase: Thorium(IV) coordinated by neutral tridentate ligands

Energy Technology Data Exchange (ETDEWEB)

Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Hu, Han-Shi [Department of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University (China); Li, Jun [Department of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University (China); William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory (United States)

2013-07-01

Sheltering thorium ions: A Th{sup 4+} ion supported by three neutral tetramethyl-3-oxaglutaramide ligands (L=TMOGA) is produced in the gas phase by electrospray ionization. The thorium in chiral Th(L){sub 3}{sup 4+} is coordinated by nine oxygen atoms. Quantum chemical studies revealed a decrease in Th-O binding energies and bond orders and an increase in bond lengths, as the number of coordinating ligands increases. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Quadruple metal-metal bonds with strong donor ligands. Ultraviolet photoelectron spectroscopy of M{sub 2}(form){sub 4} (M = Cr, Mo, W; form = N,N{prime}-diphenylformamidinate)

Energy Technology Data Exchange (ETDEWEB)

Lichtenberger, D.L.; Lynn, M.A.; Chisholm, M.H.

1999-12-29

The He I photoelectron spectra of M{sub 2}(form){sub 4}(M = Cr, Mo, W; form - N,N{prime}-diphenylformamidinate) and Mo{sub 2}(cyform){sub 4} (cyform = N,N{prime}-dicyclohexylformamidinate) are presented. For comparison, the Ne I, He I, and He II photoelectron spectra of Mo{sub 2}(p-CH{sub 3}-form){sub 4} have also been obtained. The valence ionization features of these molecules are interpreted based on (1) the changes that occur with the metal and ligand substitutions, (2) the changes in photoelectron cross sections with excitation source, and (3) the changes from previously studied dimetal complexes. These photoelectron spectra are useful for revealing the effects that better electron donor ligands have on the valence electronic structure of M{sub 2}(L-L){sub 4} systems. Comparison with the He I spectra of the isoelectronic M{sub 2}(O{sub 2}CCH{sub 3}){sub 4} compounds is particularly revealing. Unlike with the more electron-withdrawing acetate ligand, several formamidinate-based ionizations derived from the nitrogen p{sub {pi}} orbitals occur among the metal-metal {sigma}, {pi}, and {delta} ionization bands. Although these formamidinate-based levels are close in energy to the occupied metal-metal bonds, they have little direct mixing interaction with them. The shift of the metal-metal bond ionizations to lower ionization energies for the formamidinate systems is primarily a consequence of the lower electronegativity of the ligand and the better {pi} donation into empty metal levels. The metal-metal {delta} orbital experiences some additional net bonding interaction with ligand orbitals of the same symmetry. Also, an additional bonding interaction from ligand-to-metal electron donation to the {delta}* orbital is identified. These spectra suggest a greater degree of metal-ligand covalency than in the related M{sub 2}(O{sub 2}CCH{sub 3}){sub 4} systems. Fenske-Hall molecular orbital and density functional (ADF) calculations agree with the assignment and

Towards an interpretation of the mechanism of the actinides(III)/lanthanides(III) separation by synergistic solvent extraction with nitrogen-containing polydendate ligands; Vers une interpretation des mecanismes de la separation actinides(III)/lanthanides(III) par extraction liquide-liquide synergique impliquant des ligands polyazotes

Energy Technology Data Exchange (ETDEWEB)

Francois, N [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, (DRRV), 30 - Marcoule (France); Universite Henri Poincare, 54 - Vandoeuvre-les-Nancy (France)

2000-07-01

In the field of the separation of long-lived radionuclides from the wastes produced by nuclear fuel reprocessing, aromatic nitrogen-containing polydendate ligands are potential candidates for the selective extraction, alone or in synergistic mixture with acidic extractants, of trivalent actinides from trivalent lanthanides. The first part of this work deals with the complexation of trivalent f cations with various nitrogen-containing ligands (poly-pyridine analogues). Time-resolved laser-induced fluorimetry (TRLIF) and UV-visible spectrophotometry were used to determine the nature and evaluate the stability of each complex. Among the ligands studied, the least basic Me-Btp proved to be highly selective towards americium(III) in acidic solution. In the second part, two synergistic systems (nitrogen-containing polydendate ligand and lipophilic carboxylic acid) are studied and compared in regard to the extraction and separation of lanthanides(III) and actinides(III). TRLIF and gamma spectrometry allowed the nature of the extracted complexes and the optimal conditions of efficiency of both systems to be determined. Comparison between these different studies showed that the selectivity of complexation of trivalent f cations by a given nitrogen-containing polydendate ligand could not always be linked to the Am(III)Eu(III) selectivity reached in synergistic extraction. The latter depends on the 'balance' between the acid-basic properties on the one hand, and on the hard-soft characteristics on the other hand, of both components of synergistic system. (author)

Towards an interpretation of the mechanism of the actinides(III)/lanthanides(III) separation by synergistic solvent extraction with nitrogen-containing polydendate ligands; Vers une interpretation des mecanismes de la separation actinides(III)/lanthanides(III) par extraction liquide-liquide synergique impliquant des ligands polyazotes

Energy Technology Data Exchange (ETDEWEB)

Francois, N. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, (DRRV), 30 - Marcoule (France); Universite Henri Poincare, 54 - Vandoeuvre-les-Nancy (France)

2000-07-01

In the field of the separation of long-lived radionuclides from the wastes produced by nuclear fuel reprocessing, aromatic nitrogen-containing polydendate ligands are potential candidates for the selective extraction, alone or in synergistic mixture with acidic extractants, of trivalent actinides from trivalent lanthanides. The first part of this work deals with the complexation of trivalent f cations with various nitrogen-containing ligands (poly-pyridine analogues). Time-resolved laser-induced fluorimetry (TRLIF) and UV-visible spectrophotometry were used to determine the nature and evaluate the stability of each complex. Among the ligands studied, the least basic Me-Btp proved to be highly selective towards americium(III) in acidic solution. In the second part, two synergistic systems (nitrogen-containing polydendate ligand and lipophilic carboxylic acid) are studied and compared in regard to the extraction and separation of lanthanides(III) and actinides(III). TRLIF and gamma spectrometry allowed the nature of the extracted complexes and the optimal conditions of efficiency of both systems to be determined. Comparison between these different studies showed that the selectivity of complexation of trivalent f cations by a given nitrogen-containing polydendate ligand could not always be linked to the Am(III)Eu(III) selectivity reached in synergistic extraction. The latter depends on the 'balance' between the acid-basic properties on the one hand, and on the hard-soft characteristics on the other hand, of both components of synergistic system. (author)

Supramolecular architectures constructed using angular bipyridyl ligands

International Nuclear Information System (INIS)

Barnett, Sarah Ann

2003-01-01

This work details the synthesis and characterization of a series of coordination frameworks that are formed using bidentate angular N-donor ligands. Pyrimidine was reacted with metal(ll) nitrate salts. Reactions using Cd(NO 3 ) 2 receive particular focus and the analogous reactions using the linear ligand, pyrazine, were studied for comparison. In all cases, two-dimensional coordination networks were prepared. Structural diversity is observed for the Cd(ll) centres including metal-nitrate bridging. In contrast, first row transition metal nitrates form isostructural one-dimensional chains with only the bridging N-donor ligands generating polymeric propagation. The angular ligand, 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt), was reacted with Cd(NO 3 ) 2 and Zn(NO 3 ) 2 . Whereas Zn(NO 3 ) 2 compounds exhibit solvent mediated polymorphism, a range of structures were obtained for the reactions with Cd(NO 3 ) 2 , including the first example of a doubly parallel interpenetrated 4.8 2 net. 4,7-phenanthroline, was reacted with various metal(ll) nitrates as well as cobalt(ll) and copper(ll) halides. The ability of 4,7-phenanthroline to act as both a N-donor ligand and a hydrogen bond acceptor has been discussed. Reactions of CuSCN with pyrimidine yield an unusual three-dimensional structure in which polymeric propagation is not a result of ligand bridging. The reaction of CuSCN with dpt yielded structural supramolecular isomers. (author)

Structure and electronic properties of Alq3 derivatives with electron acceptor/donor groups at the C4 positions of the quinolate ligands: a theoretical study.

Science.gov (United States)

Rao, Joshi Laxmikanth; Bhanuprakash, Kotamarthi

2011-12-01

The molecular structures of the ground (S(0)) and first singlet excited (S(1)) states of Alq3 derivatives in which pyrazolyl and 3-methylpyrazolyl groups are substituted at the C4 positions of the 8-hydroxyquinolate ligands as electron acceptors, and piperidinyl and N-methylpiperazinyl groups are substituted at the same positions as electron donors, have been optimized using the B3LYP/6-31G and CIS/6-31G methods, respectively. In order to analyze the electronic transitions in these derivatives, the frontier molecular orbital characteristics were analyzed systematically, and it was found that the highest occupied molecular orbital is localized on the A ligand while the lowest unoccupied molecular orbital is localized on the B ligand in their ground states, similar to what is seen for mer-Alq3. The absorption and emission spectra were evaluated at the TD-PBE0/6-31G level, and it was observed that electron acceptor substitution causes a red-shift in the emission spectra, which is also seen experimentally. The reorganization energies were calculated at the B3LYP/6-31G level and the results show that acceptor/donor substitution has a significant effect on the intrinsic charge mobilities of these derivatives as compared to mer-Alq3.

Synthesis and Characterization of Ag(I) and Pd(II) Complexes with a Pyridine Substituted N-Heterocyclic Carbene Ligand

Energy Technology Data Exchange (ETDEWEB)

Kim, Ga Young; Jung, Hyun Jin; Lee, Dong Heon [Chonbuk National Univ., Jeonju (Korea, Republic of); Park, Gyung Se [Kunsan National Univ., Kunsan (Korea, Republic of)

2010-06-15

We have used our new tridentate pyridine substituted N-heterocyclic carbene to generate an interesting trinuclear [((MepyCH{sub 2}){sub 2}-Im){sub 3}Ag{sub 3}]{sup 3+} complex, displaying very short Ag-Ag separations. A Pd(II)-NHC complex was prepared from [((MepyCH{sub 2}){sub 2}-Im){sub 3}Ag{sub 3}]{sup 3+} via a facile transmetallation, leading to a dimeric [(MepyCH{sub 2}){sub 2}-ImPdCl]{sub 2}{sup 2+} complex. Future plans are underway for the survey of the potential applications of these new NHC complexes as luminesent materials or homogeneous catalysts. Since Arduengo's discovery of the first isolable free carbene in 1991, N-heterocyclic carbenes (NHC) have been extensively utilized as ligands for transition metals. NHC are generally more stable than two extreme types of carbenes, the Fischer and the Schrock carbenes. They are good σ donors like most tertiary phosphins, PR{sub 3}, but the π-bonding with the metal is rather weak. The thriving studies of NHC-coordinated metal complexes produced a wide range of applications from homogeneous catalysts to materials science.

Synthesis and characterization of Ru(II) complexes with polyfunctional quinazoline-(3H)-4-ones

International Nuclear Information System (INIS)

Prabhakar, B.; Lingaiah, P.; Laxma Reddy, K.

1991-01-01

Few Ru(II) complexes of the type Ru(O-N-O) 2 with tridentate O-N-O donors and of the type RuCl 2 (O-N) 2 with bidentate O-O and O-N donors have been synthesized and characterized on the basis of analytical, conductivity, thermal, magnetic, IR, electronic and PMR spectral data. The IR and PMR spectral data of the metal complexes indicate that the lignads like 2-methyl/phenyl-3-(2'-hydroxybenzalamino) quinazoline-(3H)-4-one(MHBQ/PHBQ) act as uninegative tridentate, 2-methyl/phenyl-3-(carboxymethyl) quinazoline(3H)-4-one (MCMQ/PCMQ) as uninegative bidentate and 2-methyl/phenyl-3-(furfuralamino) quinazoline-(3H)-4-one (MFQ/PFQ), 2-methyl/phenyl-3-(acetamino) quinazoline-(3H)-4-one (MAQ/PAQ), 2-methyl/phenyl3-(uramino)quinazoline-(3H)-4-one (MUQ/PUQ) and 2-methyl/phenyl-3-thiouramino)quinazoline-(3H)-4-one-(MTUQ/PTUQ) as neutral bidentate ligands. The electronic spectral data of the complexes indicate that the arrangement around Ru(II) is octahedral. (author). 25 refs., 2 tabs

Effects of Ligands on a Ternary Hydroxo Complex Formation with Eu(III) in a Aqueous Solution: Comparison of a Pyridine-2,6-dicarboxylate with a Phthalate

International Nuclear Information System (INIS)

Park, K. K.; Cho, H. R.; Kim, W. H.; Jung, E. C.

2008-01-01

The interaction of a radionuclide with ligands in a groundwater influences its migration through a hydrogeological system due to a change in the characteristics of a dissolution and a sorption. Actinide ions are classified as a hard acid and strongly interact with ligands having an oxygen donor atom of a hard base such as a hydroxide, carbonate and carboxylate. These ligands reveal a large ionic bonding character. A number of experimental results on a binary complex formation of actinides have been reported. However, actinides may easily form a ternary complex by interacting simultaneously with two different ligands, since an ionic bonding does not restrict the spatial orientation of a ligand. In previous studies, a ternary hydroxo complex formation was investigated by using pyridine-2,6-dicarboxylate (PDA) or phthalate as an organic ligand and Eu(III) as an analogue of an actinide(III) ion. Although these organic ligands equally contain two carboxylate groups that interact with an Eu(III) ion, their stabilities reveal big differences. PDA is a tridentate ligand forming two 5-membered chelates, while phthalate is a bidentate ligand forming a 7-membered chelate. The latter reveals a lower stability than the former due to an angle strain. This is one of the reasons for the lower stability of the Eu(III)-phthalate than that of the Eu(III)- PDA. The difference in the stabilities of binary complexes, EuL + (L=organic ligand), influences the stabilities of the ternary hydroxo complexes, Eu(OH)L. The coordination of a phenylic or pyridine ligand can greatly enhance the fluorescence of an Eu(III) ion due to the high absorbance of a ligand by a π → π * transition and the transfer of this energy to an Eu(III) ion. These fluorescence characteristics in a binary complex system could be changed in a ternary complex. In this study, the effect of a ligand on the stability of a ternary hydroxo complex is reported by comparing the stabilities of Eu-PDA with Eu-phthalate systems

Reduction of dinitrogen ligands

International Nuclear Information System (INIS)

Richards, R.L.

1983-01-01

Processes of dinitrogen ligand reduction in complexes of transition metals are considered. The basic character of the dinitrogen ligand is underlined. Data on X-ray photoelectronic spectroscopy and intensities of bands ν (N 2 ) in IR-spectra of nitrogen complexes are given. The mechanism of protonation of an edge dinitrogen ligand is discussed. Model systems and mechanism of nitrogenogenase are compared

Synthesis, Characterization and Antibacterial Studies of N-(Benzothiazol-2-yl)-4-chlorobenzenesulphonamide and Its Neodymium(III) and Thallium(III) Complexes.

Science.gov (United States)

Obasi, Lawrence Nnamdi; Oruma, Uchechukwu Susan; Al-Swaidan, Ibrahim Abdulrazak; Ramasami, Ponnadurai; Ezeorah, Chigozie Julius; Ochonogor, Alfred Ezinna

2017-02-22

N -(Benzothiazol-2-yl)-4-chlorobenzenesulphonamide (NBTCS) was synthesized by condensation reaction of 4-chlorobenzenesulphonyl chloride and 2-aminobenzothiazole in acetone under reflux. Neodymium(III) and thallium(III) complexes of the ligand were also synthesized. Both ligand and metal complexes were characterized using UV-Vis, IR, ¹H- and 13 C-NMR spectroscopies, elemental analysis and molar conductance measurement. IR studies revealed that the ligand is tridentate and coordinates to the metal ions through nitrogen and oxygen atoms of the sulphonamide group and nitrogen atom attached to benzothiazole ring. The neodymium(III) complex displays a coordination number of eight while thallium(III) complex displays a coordination number of six. The ligand and its complexes were screened in vitro for their antibacterial activities against Escherichia coli strains ( E. coli 6 and E. coli 13 ), Proteus species, Staphylococcus aureus and Pseudomonas aeruginosa using the agar well diffusion technique. The synthesized compounds were found to be more active against the microorganisms screened relative to ciprofloxacin, gentamicin and co-trimoxazole.

TRIDENT-CTR: a two-dimensional transport code for CTR applications

International Nuclear Information System (INIS)

Seed, T.J.

1978-01-01

TRIDENT-CTR is a two-dimensional x-y and r-z geometry multigroup neutral transport code developed at Los Alamos for toroidal calculations. The use of triangular finite elements gives it the geometric flexibility to cope with the nonorthogonal shapes of many toroidal designs of current interest in the CTR community

Synthesis and characterisation of nitrogen poly-heterocyclic molecules using as selective complexing agents of metallic cations

International Nuclear Information System (INIS)

Alphonse, F.A.

2003-12-01

Separation of actinides (III) from lanthanides (III) is a crucial problem in the reprocessing of used nuclear fuels. Experimental results shown that soft donor extractants such as nitrogen polydentate heterocycles containing a NCCNCCN coordination site are potentials ligands for selective extraction of actinides (III). In those cases, two types of liquid-liquid extractions are employed: synergistic combination with lipophilic acid extractants and direct extraction. On the basis of the Hard and Soft Acids and Bases theory and basicity evaluation, new extractants were defined. We have first studied the synthesis of potential 1,3,5-triazine ligands designed for extraction in synergy with α-bromodecanoic acid. Secondly, we have examined the synthesis of bis-triazinyl-pyridine ligands for direct extraction studies. Extraction tests were carried out and perspectives of synthesis were deducted from those extraction results. (author)

The spin relaxation of nitrogen donors in 6H SiC crystals as studied by the electron spin echo method

Science.gov (United States)

Savchenko, D.; Shanina, B.; Kalabukhova, E.; Pöppl, A.; Lančok, J.; Mokhov, E.

2016-04-01

We present the detailed study of the spin kinetics of the nitrogen (N) donor electrons in 6H SiC wafers grown by the Lely method and by the sublimation "sandwich method" (SSM) with a donor concentration of about 1017 cm-3 at T = 10-40 K. The donor electrons of the N donors substituting quasi-cubic "k1" and "k2" sites (Nk1,k2) in both types of the samples revealed the similar temperature dependence of the spin-lattice relaxation rate (T1-1), which was described by the direct one-phonon and two-phonon processes induced by the acoustic phonons proportional to T and to T9, respectively. The character of the temperature dependence of the T1-1 for the donor electrons of N substituting hexagonal ("h") site (Nh) in both types of 6H SiC samples indicates that the donor electrons relax through the fast-relaxing centers by means of the cross-relaxation process. The observed enhancement of the phase memory relaxation rate (Tm-1) with the temperature increase for the Nh donors in both types of the samples, as well as for the Nk1,k2 donors in Lely grown 6H SiC, was explained by the growth of the free electron concentration with the temperature increase and their exchange scattering at the N donor centers. The observed significant shortening of the phase memory relaxation time Tm for the Nk1,k2 donors in the SSM grown sample with the temperature lowering is caused by hopping motion of the electrons between the occupied and unoccupied states of the N donors at Nh and Nk1,k2 sites. The impact of the N donor pairs, triads, distant donor pairs formed in n-type 6H SiC wafers on the spin relaxation times was discussed.

Diverse Cd(II) compounds based on N-benzoyl-L-glutamic acid and N-donor ligands: Structures and photoluminescent properties

Science.gov (United States)

Ma, Ning; Guo, Wei-Ying; Song, Hui-Hua; Yu, Hai-Tao

2016-01-01

Five new Cd(II) coordination polymers with N-benzoyl-L-glutamic acid (H2bzgluO) and different N-donor ligands, [Cd(bzgluO)(2,2‧-bipy)(H2O)]n (1), [Cd(bzgluO)(2,4‧-bipy)2(H2O)·3H2O]n (2), [Cd(bzgluO)(phen)·H2O]n (3), [Cd(bzgluO)(4,4‧-bipy)(H2O)]n (4), [Cd(bzgluO)(bpp)(H2O)·2H2O]n (5) were synthesized (2,2‧-bipy=2,2‧-bipyridine, 2,4‧-bipy=2,4‧-bipyridine, phen=1,10-phenanthroline, 4,4‧-bipy=4,4‧-bipyridine, bpp=1,3-di(4-pyridyl)propane). Compounds 1-2 exhibit a 1D single-chain structure. Compound 1 generates a 2D supramolecular structure via π-π stacking and hydrogen bonding, 3D architecture of compound 2 is formed by hydrogen bonding. Compound 3 features a 1D double-chain structure, which are linked by π-π interactions into a 2D supramolecular layer. Compounds 4-5 display a 2D network structure. Neighboring layers of 4 are extended into a 3D supramolecular architecture through hydrogen bonding. The structural diversity of these compounds is attributed to the effect of ancillary N-donor ligands and coordination modes of H2bzgluO. Luminescent properties of 1-5 were studied at room temperature. Circular dichroism of compounds 1, 2 and 5 were investigated.

Synthesis, structural studies and antimicrobial activity of N'-((2Z, 3E)-3-(hydroxyimino)butan-2-ylidene)-2-phenylacetohydrazide and its Co(II), Ni(II) complexes

Science.gov (United States)

Karadeniz, Şeyma; Ataol, Cigdem Yuksektepe; Şahin, Onur; İdil, Önder; Bati, Hümeyra

2018-06-01

A new aroylhydrazoneoxime, N'-((2Z, 3E)-3-(hydroxyimino)butan-2-ylidene)-2-phenylacetohydrazide ligand (LH2) and its Ni(II) and Co(II) complexes, have been synthesized and characterized by elemental and thermal analyses, IR and UV-vis spectroscopy, magnetic moment and X-ray diffraction. The antimicrobial activities of these compounds were tested by using minimal inhibitory concentration method (MIC). The ligand-containing aroylhydrazone and oxime groups and its Ni complex crystallize in the triclinic system and P 1 - space group, while its Co complex crystallizes in the monoclinic system and the C 2/c space group. X-ray results show that the ligand in the keto form is transformed into enolic form when it forms coordination. From elemental analysis data, the stoichiometry of Co(II) complex was found to be 1:2 (metal/ligand), but 1:1 for Ni(II). IR spectra indicate that the ligand acts as monoanionic NNO- tridentate and coordination takes place form through the oxime nitrogen, imine nitrogen, and enolate oxygen atoms.

Organotellurium ligands – designing and complexation reactions

Indian Academy of Sciences (India)

Unknown

membered rings it is negative and ~30 ppm only. Keywords. Organotellurium ligands; hybrid telluroether; platinum metal complexes; tellurium-125 NMR. 1. Introduction. Tellurium is the noblest metalloid which may act as a Lewis acid as well as Lewis base. The ligand chemistry of tellurium, which acts as a 'soft' donor, was ...

Electronic and spatial structures of water-soluble dinitrosyl iron complexes with thiol-containing ligands underlying their ability to act as nitric oxide and nitrosonium ion donors.

Science.gov (United States)

Vanin, Anatoly F; Burbaev, Dosymzhan Sh

2011-01-01

The ability of mononuclear dinitrosyl iron commplexes (M-DNICs) with thiolate ligands to act as NO donors and to trigger S-nitrosation of thiols can be explain only in the paradigm of the model of the [Fe(+)(NO(+))(2)] core ({Fe(NO)(2)}(7) according to the Enemark-Feltham classification). Similarly, the {(RS(-))(2)Fe(+)(NO(+))(2)}(+) structure describing the distribution of unpaired electron density in M-DNIC corresponds to the low-spin (S = 1/2) state with a d(7) electron configuration of the iron atom and predominant localization of the unpaired electron on MO(d(z2)) and the square planar structure of M-DNIC. On the other side, the formation of molecular orbitals of M-DNIC including orbitals of the iron atom, thiolate and nitrosyl ligands results in a transfer of electron density from sulfur atoms to the iron atom and nitrosyl ligands. Under these conditions, the positive charge on the nitrosyl ligands diminishes appreciably, the interaction of the ligands with hydroxyl ions or with thiols slows down and the hydrolysis of nitrosyl ligands and the S-nitrosating effect of the latter are not manifested. Most probably, the S-nitrosating effect of nitrosyl ligands is a result of weak binding of thiolate ligands to the iron atom under conditions favoring destabilization of M-DNIC.

Imine derivatives of lathonones. Part I -- Reactions of neodymium (III) isopropoxide with monofunctional bidendtate and bifunctional tridentate aldimines and ketamines

International Nuclear Information System (INIS)

Mital, S.P.; Singh, R.V.; Tandon, J.P.

1980-01-01

Nd(OPrsup(i))sub(2) (SB) and Nd(Oprsup(i))(SB)sub(2) [where SBH represents the molecule of monofunctional bidentate aldimine] type of derivatives have been synthesised by 1:1 and 1:2 molar reactions of neodymium isopropoxide with the aldimines having the donor system NOH and formed by the condensation of salicylaldehyde with alkylamines. However, bifunctional tridentate Schiff bases (LH) 2 have been found to yield Nd(OPrsup(i)) (L) and Nd 2 (L) 3 type of complexes in 1:1 and 2:3 molar ratio respectively. The isopropoxy groups of the 1:1 complexes have been found to undergo replacement reactions with excess of t-butanol and the resulting complexes are hydrolytically stable. All the newly synthesized complexes have been characterized on the basis of elemental analyses, molecular weight determinations, conductance measurements and infrared and proton magnetic resonance spectral studies. (auth.)

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.

Pinhole aperture point backlighter development experiments on Trident, 9-13, 2001

International Nuclear Information System (INIS)

Lanier, N.E.; Murphy, Thomas J.

2001-01-01

Pinhole aperture point backlighter (PAPBL) imaging has been used on experiments on Omega, but results have been compromised by large backgrounds. This technique has advantages over traditional area backlighting/pinhole imaging, and the Omega experiments could benefit from this capability, but Omega time is expensive and not the place for developing diagnostic techniques if they can be developed on Trident instead. PAPBL, shot from Direct Drive Cylinder Mix experiments on Omega (DDCYLMIX 00-1, January 18 and 19, 2000). (See LA-UR-00-4187, Post-Shot Report, Direct Drive Cylinder Mix). In this campaign, they used Trident to obtain clean PAPBL images. Having accomplished that, they attempted to replicate the noise environment of Omega by producing hot electrons and having them impinge on material to produce high-energy x-rays similar to those that might be produced by hot electrons impinging on diagnostics or target positioner components on Omega. Backlighter target design was based, to some degree, on that shown by Bullock et al. at the 42nd Annual APS-DPP Meeting in Quebec City, Quebec, Canada, October 23-27, 2000. (A.B. Bullock et al., Bull. Am. Phys. Soc. 45,(7) 359 (2000); A.B. Bullock et al., Rev. Sci. Instrum. 72, 690 (2001).) We accomplished this to some degree and then attempted, with some success, to obtain a good PAPBL image in the presence of this noise. Results of this work suggest methods that might reduce the background noise in Omega PAPBL images. The goals are to obtain a pinhole aperture point backlighter (PAPBL) image on Trident and develop a method to simulate the high-energy background contribution to PAPBL imnages seen on Omega experients in order to allow future experiments to optimize signal-to-noise in PAPBL imaging.

Electronic transitions and bonding properties in a series of five-coordinate "16-electron" complexes [Mn(CO)3(L2)]- (L2 = chelating redox-active .pi.-donor ligand)

Czech Academy of Sciences Publication Activity Database

Hartl, F.; Rosa, P.; Ricard, L.; Le Floch, P.; Záliš, Stanislav

2007-01-01

Roč. 251, 3-4 (2007), s. 557-576 ISSN 0010-8545 R&D Projects: GA MŠk 1P05OC068; GA AV ČR 1ET400400413 Institutional research plan: CEZ:AV0Z40400503 Keywords : manganese carbonyl * .pi.-donor ligand * electronic delocalization * Five-coordinate complex Subject RIV: CG - Electrochemistry Impact factor: 8.568, year: 2007

Antioxidant, electrochemical, thermal, antimicrobial and alkane oxidation properties of tridentate Schiff base ligands and their metal complexes

Science.gov (United States)

Ceyhan, Gökhan; Çelik, Cumali; Uruş, Serhan; Demirtaş, İbrahim; Elmastaş, Mahfuz; Tümer, Mehmet

2011-10-01

In this study, two Schiff base ligands (HL 1 and HL 2) and their Cu(II), Co(II), Ni(II), Pd(II) and Ru(III) metal complexes were synthesized and characterized by the analytical and spectroscopic methods. Alkane oxidation activities of the metal complexes were studied on cyclohexane as substrate. The ligands and their metal complexes were evaluated for their antimicrobial activity against Corynebacterium xerosis, Bacillus brevis, Bacillus megaterium, Bacillus cereus, Mycobacterium smegmatis, Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis (as Gram-positive bacteria) and Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Yersinia enterocolitica, Klebsiella fragilis, Saccharomyces cerevisiae, and Candida albicans (as Gram-negative bacteria). The antioxidant properties of the Schiff base ligands were evaluated in a series of in vitro tests: 1,1-diphenyl-2-picrylhydrazyl (DPPH rad ) free radical scavenging and reducing power activity of superoxide anion radical generated non-enzymatic systems. Electrochemical and thermal properties of the compounds were investigated.

Synthesis, Characterization and Antibacterial Studies of N-(Benzothiazol-2-yl-4-chlorobenzenesulphonamide and Its Neodymium(III and Thallium(III Complexes

Directory of Open Access Journals (Sweden)

Lawrence Nnamdi Obasi

2017-02-01

Full Text Available N-(Benzothiazol-2-yl-4-chlorobenzenesulphonamide (NBTCS was synthesized by condensation reaction of 4-chlorobenzenesulphonyl chloride and 2-aminobenzothiazole in acetone under reflux. Neodymium(III and thallium(III complexes of the ligand were also synthesized. Both ligand and metal complexes were characterized using UV-Vis, IR, 1H- and 13C-NMR spectroscopies, elemental analysis and molar conductance measurement. IR studies revealed that the ligand is tridentate and coordinates to the metal ions through nitrogen and oxygen atoms of the sulphonamide group and nitrogen atom attached to benzothiazole ring. The neodymium(III complex displays a coordination number of eight while thallium(III complex displays a coordination number of six. The ligand and its complexes were screened in vitro for their antibacterial activities against Escherichia coli strains (E. coli 6 and E. coli 13, Proteus species, Staphylococcus aureus and Pseudomonas aeruginosa using the agar well diffusion technique. The synthesized compounds were found to be more active against the microorganisms screened relative to ciprofloxacin, gentamicin and co-trimoxazole.

The spin relaxation of nitrogen donors in 6H SiC crystals as studied by the electron spin echo method

Energy Technology Data Exchange (ETDEWEB)

Savchenko, D., E-mail: dariyasavchenko@gmail.com [Institute of Physics of the Czech Academy of Sciences, Prague 182 21 (Czech Republic); National Technical University of Ukraine “Kyiv Polytechnic Institute,” Kyiv 03056 (Ukraine); Shanina, B.; Kalabukhova, E. [V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028 (Ukraine); Pöppl, A. [Institute of Experimental Physics II, Leipzig University, Leipzig D-04103 (Germany); Lančok, J. [Institute of Physics of the Czech Academy of Sciences, Prague 182 21 (Czech Republic); Mokhov, E. [A.F. Ioffe Physical Technical Institute, RAS, St. Petersburg 194021 (Russian Federation); Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg 19710 (Russian Federation)

2016-04-07

We present the detailed study of the spin kinetics of the nitrogen (N) donor electrons in 6H SiC wafers grown by the Lely method and by the sublimation “sandwich method” (SSM) with a donor concentration of about 10{sup 17 }cm{sup −3} at T = 10–40 K. The donor electrons of the N donors substituting quasi-cubic “k1” and “k2” sites (N{sub k1,k2}) in both types of the samples revealed the similar temperature dependence of the spin-lattice relaxation rate (T{sub 1}{sup −1}), which was described by the direct one-phonon and two-phonon processes induced by the acoustic phonons proportional to T and to T{sup 9}, respectively. The character of the temperature dependence of the T{sub 1}{sup −1} for the donor electrons of N substituting hexagonal (“h”) site (N{sub h}) in both types of 6H SiC samples indicates that the donor electrons relax through the fast-relaxing centers by means of the cross-relaxation process. The observed enhancement of the phase memory relaxation rate (T{sub m}{sup −1}) with the temperature increase for the N{sub h} donors in both types of the samples, as well as for the N{sub k1,k2} donors in Lely grown 6H SiC, was explained by the growth of the free electron concentration with the temperature increase and their exchange scattering at the N donor centers. The observed significant shortening of the phase memory relaxation time T{sub m} for the N{sub k1,k2} donors in the SSM grown sample with the temperature lowering is caused by hopping motion of the electrons between the occupied and unoccupied states of the N donors at N{sub h} and N{sub k1,k2} sites. The impact of the N donor pairs, triads, distant donor pairs formed in n-type 6H SiC wafers on the spin relaxation times was discussed.

Scandium, yttrium and the lanthanides

International Nuclear Information System (INIS)

Hart, F.A.

1987-01-01

This chapter on the chemistry of the coordination complexes of scandium, yttrium and the lanthanides includes sections on the nitrogen and oxygen donor ligands and complex halides of scandium, and the phosphorus and sulfur donor ligands of yttrium and the lanthanides. Complexes with the macrocylic ligands and with halides are also discussed. Sections on the NMR and electronic spectra of the lanthanides are also included. (UK)

The Synthesis and X-ray Structural Characterization of mer and fac isomers of the Technetium(I) Nitrosyl Complex [TcCl(2)(NO)(PNPpr)].

Science.gov (United States)

Nicholson, T L; Mahmood, A; Refosco, F; Tisato, F; Müller, P; Jones, A G

2009-08-01

The nitrosyl complex H[TcNOCl(4)] reacts with the tridentate ligand bis[(2-diphenylphosphino)propyl]amine (PNPpr) to yield a mixture of the mer or fac isomers of [TcCl(2)(NO)(PNPpr)]. In acetonitrile, where the ligand is freely soluble, reaction occurs at room temperature to yield mostly the mer isomer with the linear nitrosyl ligand cis to the amine ligand; and the phosphine ligands arranged in a mutually trans orientation. The reaction in methanol requires reflux to dissolve the lipophilic ligand and generates the fac isomer of [TcCl2(NO)(PNPpr)] as the major product, with the tridentate ligand in a facial arrangement, leaving the chlorides and nitrosyl ligand in the remaining facial sites. The steric bulk of the tridentate ligand's diphenylphophino- moieties results in a significant distortion from octahedral geometry, with the P-Tc-P bond angle expanded to 99.48(4)°. The infrared spectra display absorptions from these nitrosyl ligands in the 1700 and 1800 cm(-1) regions for the fac and mer isomers respectively. The ESI(+) mass spectra each display the parent ion at 647 m/z.

Some organodioxygen complexes of molybdenum(VI), tungsten(VI), zinc(II) and cadmium(II) containing some monodentate and multidentate ligands

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Leo Man Lin; Grouse, Karen A.; Mariotto, Gino

2003-08-01

Several novel organodioxygen complexes of the type [M(O)(O 2 ) 2 L](MMo(VI), W(VI)) and [M'(O 2 )L](M'= Cd(II) and Zn(II)) have been synthesized using monodentate, bidentate and tridentate ligands, L pyridine, picolinic acid, diethylenetriamine, 1,2-phenylenediamine, triphenylphosphine oxide. These complexes were characterized by elemental analyses, conductivity measurements, infrared, Raman spectral studies. For dioxygen complexes, the v(O=O) stretches of the superoxo moities were only Raman active, because of apparent linearity of the M-O 2 moieties, giving peaks at 1020-1030 cm -1 . The complexes were all thermodynamically stable. The dioxygen complexes containing bidentate co-ligands were found to show oxygen transfer reactions to various organic and inorganic substrates. Mechanisms have been postulated. (author)

The TRIDENT laser at LANL: New “dial-a-contrast” and high-contrast experimental capabilities

Directory of Open Access Journals (Sweden)

Flippo K.A.

2013-11-01

Full Text Available The Trident laser facility at Los Alamos National Laboratory (LANL has served for more than 20 years as an important tool in inertial confinement fusion (ICF and Material Dynamics research. An energy and power upgrade of the short-pulse beam line to 100J / 200 TW was made in 2007 and contrast improvements have been made continually since. The combination of this powerful new short-pulse beamline with the two flexible long pulse beamlines, and a total of three different target areas, makes Trident a highly flexible and versatile research tool for high energy density laboratory plasma (HEDLP research. The newest “Dial-a-Contrast” (DaC features are described, along with nominal performance of the laser at the presently available highest contrast.

Synergistic extraction of Th(IV) by 2-hydroxy-1-naphthaldehyde thiosemicarbazone and neutral donors

International Nuclear Information System (INIS)

Banerjee, S.; Basu, S.

2003-01-01

The extraction behaviour of Th(IV) from aqueous nitric acid medium employing 2-hydroxy-1-naphthaldehyde thiosemicarbazone has been studied in the presence of various donors, like trioctyl phosphine oxide (TOPO), calix[3]OH[3]OMe[6]arene, trioctyl amine (TOA), dimethyl sulphoxide (DMSO) in ethylacetate solvent. The constants (log k ex ) for the binary complex in organic phase [Th(A)(NO 3 ) 3 ], where A is the ligand, was found to be 3.99, which was by far the largest amongst the corresponding values known for the other thiosemicarbazones. The overall equilibrium constants (log K) for the ternary species [Th(A)TOPO(NO 3 ) 3 ], [Th(A)TOA(NO 3 ) 3 ], [Th(A)Calix[3]OH[3]OMe[6]arene(NO 3 ) 3 ], [Th(A)DMSO(NO 3 ) 3 ] were estimated to be 8.287, 8.862, 8.415, 6.921 respectively. The trend in equilibrium constants were in accordance with the substitution of the donor. The extraction of Th 4+ by the ligand-donor combination was maximum at pH = 1 and extraction decreases with increase in pH. It has been found that the extent of extraction of Th 4+ in the organic phase as the binary as well as ternary complex [Th(A)(NO 3 ) 3 ] and [Th(A)(NO 3 ) 3 S], where S is the donor, increases with increase in the concentration of the ligand. Similar trend is obtained in the extraction by donors in absence of ligand. In case of ternary extraction, using different donors, amines are found to perform best compared to the other donors. The trend is as follows: TOA > calix[3]OH[3]OMe[6]arene > TOPO > DMSO. In addition, the effect of different diluents on extraction was also studied and the observed trend was methyl salicylate > ethyl acetate > methyl isobutyl ketone > ethyl benzoate. (orig.)

Structure and properties of silver sulfate complexes derived from dipyridyl methylthio ligands with secondary donor site

Energy Technology Data Exchange (ETDEWEB)

Chen, Wen-Hua; Yan, Hao-Jie; Chen, Hui; Liu, Rui-Heng; Li, Ai-Min; Wang, Guo [Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048 (China); Wan, Chong-Qing, E-mail: wancq@cnu.edu.cn [Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048 (China); State Key Laboratory of Structural Chemistry in China, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2017-06-15

Dipyridyl sulphide ligands 4-(pyridin-4-ylmethylthio)pyridine (abbreviated as L1) and 3-(pyridin-4-ylmethylthio)pyridine (abbreviated as L2) have been designed and used as μ-{sub N},{sub N}-bridging linkages to construct coordination polymers with free –S–CH{sub 2}– groups as secondary donor sites. By use solvent control method, coordination polymers ([Ag{sub 3}SO{sub 4}(L1){sub 3}](Cl)·4.5H{sub 2}O){sub ∞}(1), ([Ag{sub 2}SO{sub 4}(L1){sub 2}]·6H{sub 2}O·2CH{sub 3}OH){sub ∞}(2), ([Ag{sub 2}SO{sub 4}(L2){sub 2}]·H{sub 2}O){sub ∞}(3) and ([Ag{sub 4}(SO{sub 4}){sub 2}(L2){sub 4}]·5H{sub 2}O){sub ∞}(4) with different architectures were obtained. Complexes 1, 3 and 4 feature 1D channel with different sizes and structures. Complex 1 exhibits guest exchange by THF and 1,4-dioxane, and Hg{sup 2+} sorption ability from solution due to its relative larger channel and available bonding sites of –S– exposed to the channel region. All complexes have been characterized through single-crystal and powder X-ray diffraction (PXRD), FT-IR spectra, X-ray photoelectron spectroscopy (XPS), elemental and thermogravimetric analyses. The guest exchange and Hg{sup 2+} sorption were monitored and identified, and the structure-property relationship of coordination polymers 1–4 are discussed. - Graphical abstract: Coordination polymers of silver(I) sulfate with secondary donor sites are shown guest exchange property and Hg{sup 2+} absorb ability from solution. This work provides a new method to construct functional materials with potential application. - Highlights: • New example of constructing functional coordination polymer with secondary donor methylthio group. • Guest exchange and interesting Hg(II) absorb ability from solution are investigated. • New method to construct functional materials with potential application.

A novel tridentate Schiff base dioxo-molybdenum(VI) complex: synthesis, experimental and theoretical studies on its crystal structure, FTIR, UV-visible, ¹H NMR and ¹³C NMR spectra.

Science.gov (United States)

Saheb, Vahid; Sheikhshoaie, Iran; Stoeckli-Evans, Helen

2012-09-01

A new dioxo-molybdenum(VI) complex [MoO(2)(L)(H(2)O)] has been synthesized, using 5-methoxy 2-[(2-hydroxypropylimino)methyl]phenol as tridentate ONO donor Schiff base ligand (H(2)L) and MoO(2)(acac)(2). The yellow crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FTIR), UV-visible, (1)H NMR and (13)C NMR spectra. Electronic structure calculations at the B3LYP and PW91PW91 levels of theory are performed to optimize the molecular geometry and to calculate the UV-visible, FTIR, (1)H NMR and (13)C NMR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TDDFT) method is used to calculate the electronic transitions of the complex. All theoretical methods can well reproduce the structure of the compound. The (1)H NMR shielding tensors computed at the B3LYP/DGDZVP level of theory is in agreement with experimental (1)H NMR spectra. However, the (13)C NMR shielding tensors computed at the B3LYP level, employing a combined basis set of DGDZVP for Mo and 6-31+G(2df,p) for other atoms, are in better agreement with experimental (13)C NMR spectra. The electronic transitions calculated at the B3LYP/DGDZVP level by using TD-DFT method is in accordance with the observed UV-visible spectrum of the compound. Copyright © 2012 Elsevier B.V. All rights reserved.

The spin relaxation of nitrogen donors in 6H SiC crystals as studied by the electron spin echo method

Czech Academy of Sciences Publication Activity Database

Savchenko, Dariia; Shanina, B.; Kalabukhova, E.; Pöppl, A.; Lančok, Ján; Mokhov, E.

2016-01-01

Roč. 119, č. 13 (2016), 1-7, č. článku 135706. ISSN 0021-8979 R&D Projects: GA ČR GP13-06697P; GA MŠk LO1409; GA MŠk LM2015088 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : electron spin resonance * SiC * nitrogen donors * relaxation times Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.068, year: 2016

Synthesis, spectroscopic and DNA binding ability of CoII, NiII, CuII and ZnII complexes of Schiff base ligand (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol. X-ray crystal structure determination of cobalt (II) complex.

Science.gov (United States)

Yarkandi, Naeema H; El-Ghamry, Hoda A; Gaber, Mohamed

2017-06-01

A novel Schiff base ligand, (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol (HL), has been designed and synthesized in addition to its metal chelates [Co(L) 2 ]·l2H 2 O, [Ni(L)Cl·(H 2 O) 2 ].5H 2 O, [Cu(L)Cl] and [Zn(L)(CH 3 COO)]. The structures of the isolated compounds have been confirmed and identified by means of different spectral and physicochemical techniques including CHN analysis, 1 H & 13 C NMR, mass spectral analysis, molar conductivity measurement, UV-Vis, infrared, magnetic moment in addition to TGA technique. The infrared spectral results ascertained that the ligand acts as monobasic tridentate binding to the metal centers via deprotonated hydroxyl oxygen, azomethine and imidazole nitrogen atoms. The UV-Vis, magnetic susceptibility and molar conductivity data implied octahedral geometry for Co(II) & Ni(II) complexes, tetrahedral for Zn(II) complex and square planar for Cu(II) complex. X-ray structural analysis of Co(II) complex 1 has been reported and discussed. Moreover, the type of interaction between the ligand & its complexes towards salmon sperm DNA (SS-DNA) has been examined by the measurement of absorption spectra and viscosity which confirmed that the ligand and its complexes interact with DNA via intercalation interaction as concluded from the values of binding constants (K b ). Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of Nitrogen Surface Ligands on Propane Metathesis: Design and Characterizations of N-modified SBA15-Supported Schrock-type Tungsten Alkylidyne

KAUST Repository

Eid, Ahmed A.

2014-04-01

Catalysis, which is primarily a molecular phenomenon, is an important field of chemistry because it requires the chemical conversion of molecules into other molecules. It also has an effect on many fields, including, but not limited to, industry, environment and life Science[1]. Surface Organometallic Chemistry is an effective methodology for Catalysis as it imports the concept and mechanism of organometallic chemistry, to surface science and heterogeneous catalysis. So, it bridges the gap between homogenous and heterogeneous catalysis[1]. The aim of the present research work is to study the effect of Nitrogen surface ligands on the activity of Alkane, Propane in particular, metathesis. Our approach is based on the preparation of selectively well-defined group (VI) transition metal complexes supported onto mesoporous materials, SBA15 and bearing amido and/or imido ligands. We choose nitrogen ligands because, according to the literature, they showed in some cases better catalytic properties in homogenous catalysis in comparison with their oxygen counterparts[2]. The first section covers the modification of a highly dehydroxylated SBA15 surface using a controlled ammonia treatment. These will result in the preparation of two kind of Nitrogen surface ligands: -\\tOne with vicinal silylamine/silanol, (≡SiNH2)(≡SiOH), noted [N,O]SBA15 and, -\\tAnother\\tone\\twith\\tvicinal\\tbis-silylamine moieties (≡SiNH2)2, noted [N,N]SBA15[3]. The second section covers the reaction of Schrock type Tungsten Carbyne [W(≡C- tBu)(CH2-tBu)3] with those N-surface ligands and their characterizations by FT-IR, multiple quantum solid state NMR (1H, 13C), elemental analysis and gas phase analysis. The third section covers the generation of the active site, tungsten hydride species. Their performance toward propane metathesis reaction using the dynamic reactor technique PID compared toward previous well-known catalysts supported on silica oxide or mesoporous materials[4]. A fairly good

Ruthenium(II) carbonyl compounds with the 4'-chloro-2,2':6',2''-terpyridine ligand.

Science.gov (United States)

Tatikonda, Rajendhraprasad; Haukka, Matti

2017-04-01

Two ruthenium carbonyl complexes with the 4'-chloro-2,2':6',2''-terpyridine ligand (tpy-Cl, C 15 H 10 ClN 3 ), i.e. [RuCl(tpy-Cl)(CO) 2 ][RuCl 3 (CO) 3 ] (I) [systematic name: cis -di-carbonyl-chlorido(4'-chloro-2,2':6',2''-terpyridine-κ 3 N )ruthenium(II) fac -tricarbonyltri-chlorido-ruthenate(II)], and [RuCl 2 (tpy-Cl)(CO) 2 ] (II) [ cis -dicarbonyl- trans -di-chlorido(4'-chloro-2,2':6',2''-terpyridine-κ 2 N 1 , N 1' )ruthenium(II)], were synthesized and characterized by single-crystal X-ray diffraction. The Ru II atoms in both centrosymmetric structures (I) and (II) display similar, slightly distorted octa-hedral coordination spheres. The coordination sphere in the complex cation in compound (I) is defined by three N atoms of the tridentate tpy-Cl ligand, two carbonyl carbon atoms and one chlorido ligand; the charge is balanced by an octa-hedral [Ru(CO) 3 Cl 3 ] - counter-anion. In the neutral compound (II), the tpy-Cl ligand coordinates to the metal only through two of its N atoms. The coordination sphere of the Ru II atom is completed by two carbonyl and two chlorido ligands. In the crystal structures of both (I) and (II), weak C-H⋯Cl inter-actions are observed.

Synthesis, Characterization and Biological Evaluation of Transition Metal Complexes Derived from N, S Bidentate Ligands

Directory of Open Access Journals (Sweden)

Enis Nadia Md Yusof

2015-05-01

Full Text Available Two bidentate NS ligands were synthesized by the condensation reaction of S-2-methylbenzyldithiocarbazate (S2MBDTC with 2-methoxybenzaldehyde (2MB and 3-methoxybenzaldehyde (3MB. The ligands were reacted separately with acetates of Cu(II, Ni(II and Zn(II yielding 1:2 (metal:ligand complexes. The metal complexes formed were expected to have a general formula of [M(NS2] where M = Cu2+, Ni2+, and Zn2+. These compounds were characterized by elemental analysis, molar conductivity, magnetic susceptibility and various spectroscopic techniques. The magnetic susceptibility measurements and spectral results supported the predicted coordination geometry in which the Schiff bases behaved as bidentate NS donor ligands coordinating via the azomethine nitrogen and thiolate sulfur. The molecular structures of the isomeric S2M2MBH (1 and S2M3MBH (2 were established by X-ray crystallography to have very similar l-shaped structures. The Schiff bases and their metal complexes were evaluated for their biological activities against estrogen receptor-positive (MCF-7 and estrogen receptor-negative (MDA-MB-231 breast cancer cell lines. Only the Cu(II complexes showed marked cytotoxicity against the cancer cell lines. Both Schiff bases and other metal complexes were found to be inactive. In concordance with the cytotoxicity studies, the DNA binding studies indicated that Cu(II complexes have a strong DNA binding affinity.

Electrochemistry of oxo-technetium(V) complexes containing Schiff base and 8-quinolinol ligands

International Nuclear Information System (INIS)

Refosco, F.; Mazzi, U.; Deutsch, E.; Kirchhoff, J.R.; Heineman, W.R.; Seeber, R.

1988-01-01

The electrochemistry of six-coordinate, monooxo technetium(V) complexes containing Schiff base ligands has been studied in acetonitrile and N,N'-dimethylformamide solutions. The complexes have the general formula TcOCl(L B ) 2 or TcO(L T )(L B ), where L B represents a bidentate-N,O Schiff base ligand or a bidentate-N,O 8-quinolinol ligand and L T represents a tridentate-O,N,O Schiff base ligand. Cyclic voltammetry at a platinum-disk electrode, controlled-potential coulometry, and thin-layer spectroelectrochemistry were used to probe both the oxidation and the reduction of these complexes. The results of these studies, and previously reported results on the analogous Re(V) complexes, can be understood within a single general reaction scheme. The salient features of this scheme are (i) one-electron reduction of Tc(V) to Tc(IV), (ii) subsequent loss of a ligand situated cis to the Tc≡O linkage, and (iii) subsequent isomerization of this unstable Tc(IV) product to more stable complex in which the site trans to the Tc≡O linkage is vacant. The Tc(IV) complexes can also be reduced to analogous Tc(III) species, which appear to undergo the same ligand loss and isomerization reactions. The technetium complexes are 400-500 mV easier to reduce than are their rhenium analogues. The 8-quinolinol ligands, and especially the 5-nitro derivative, both thermodynamically and kinetically stabilize the Tc(IV) and Tc(III) oxidation states. These electrogenerated species are unusual in that they constitute the bulk of the known examples of monomeric Tc(IV) and Tc(III) complexes containing only N- and O-donating ligands. 34 refs., 9 figs., 1 tab

Syntheses and catalytic oxotransfer activities of oxo molybdenum(vi) complexes of a new aminoalcohol phenolate ligand.

Science.gov (United States)

Hossain, M K; Haukka, M; Sillanpää, R; Hrovat, D A; Richmond, M G; Nordlander, E; Lehtonen, A

2017-05-30

The new aminoalcohol phenol 2,4-di-tert-butyl-6-(((2-hydroxy-2-phenylethyl)amino)methyl)phenol (H2L) was prepared by a facile solvent-free synthesis and used as a tridentate ligand for new cis-dioxomolybdenum(vi)(L) complexes. In the presence of a coordinating solvent (DMSO, MeOH, pyridine), the complexes crystallise as monomeric solvent adducts while in the absence of such molecules, a trimer with asymmetric Mo[double bond, length as m-dash]O→Mo bridges crystallises. The complexes can catalyse epoxidation of cis-cyclooctene and sulfoxidation of methyl-p-tolylsulfide, using tert-butyl hydroperoxide as oxidant.

New functionalized β-diketiminate ligands and f elements

International Nuclear Information System (INIS)

Dulong, Florian

2013-01-01

β-diketiminate ligands have received increased interest in coordination chemistry, especially for homogeneous catalysis. Their successful applications arise from an easy and fine tuning of the ligand electronic and geometric properties. However, these modifications are limited to the introduction of neutral donors (ethers or amines), on the nitrogen substituents of the β-diketiminate skeleton. The main focus of this research project is to overcome this limitation by synthesizing new β-diketiminate ligands functionalized by one or two anionic aryl-oxide groups, and to study their coordination chemistry with lanthanide and actinide ions. Access to these species relies on a fine understanding of the mechanism underlying their formation, and the sensitivity of the β-di-iminium skeleton towards nucleophiles (phenols) has been identified as the limiting side reaction in the synthetic route. Addition of reactants in well defined order allowed the formation of two new N-aryl-oxy-β-diketiminate dianions on a multi-gram scale. The two ligands differ by their steric bulk and exhibit different coordination behaviors towards lanthanides and actinide ions, which were rationalized on geometric considerations. The reactivity of three of these new complexes has been investigated. A Ce(III) N-aryl-oxy-β-diketiminate complex exhibits interesting reduction properties, due to the shift of its oxidation potential to negative values by its coordination environment. A Th(IV) complex presents a vacant coordination site, which has been probed with different Lewis bases, emphasizing two spatial arrangements ruled by inter-ligand repulsion. It has been compared to its U(IV) analogue, which can be oxidized to a rare terminal mono-oxo uranium(VI) species. The latter was reversibly reduced to its U(V) and U(IV) derivatives, creating the first series of terminal mono-oxo uranium complexes with three successive oxidation states. These compounds represent an opportunity to better understand

Complexation of nitrogen and sulphur donor Schiff's base ligand to Cr(III) and Ni(II) metal ions: Synthesis, spectroscopic and antipathogenic studies

Science.gov (United States)

Sharma, Amit Kumar; Chandra, Sulekh

2011-01-01

2,6-Diacetyl pyridine based ligand was synthesized by the reaction of 2,6-diacetyl pyridine with thiocarbohydrazide in presence of acetic acid. The coordination compounds with Cr(III) and Ni(II) metal ions having [Cr(L)X]X 2 and [Ni(L)X]X compositions (where L = ligand and X = NO 3-, Cl - and CH 3COO -) were synthesized and characterized by physicochemical and spectral studies. The studies like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV-Vis, NMR, mass and EPR reveal that the complexes are octahedral. The compounds were examined against the pathogenic fungal and bacterial strains like Alternaria brassicae, Aspergillus niger, Fusarium oxysporum, Xanthomonas compestris and Pseudomonas aeruginosa. A. niger causes the diseases Apergillosis and Otomycosis in humans.

Synthesis, spectroscopic characterization, biological studies and DFT calculations on some transition metal complexes of NO donor ligand

Science.gov (United States)

Zordok, W. A.; Sadeek, S. A.

2018-04-01

Seven new complexes of2-oxo-4,6-diphenyl-1,2-dihyropyridine-3-carbonitrile (L) with Fe(III), Co(II), Cu(II), Zn(II), Y(III), Zr(IV) and La(III) were synthesized. The isolated solid compounds were elucidated from micro analytical, IR, electronic, mass, 1H NMR, magnetic susceptibility measurements and TG/DTG, DTA analyses. The intensity of ν(Ctbnd N) was changed to strong and shifted to around 2200 cm-1. Also, the ν(Cdbnd O) was shifted to higher frequency value (1644 cm-1). The spectra of the complexes indicate that the free ligand is coordinated to the metal ions via nitrogen of carbonitrile group and oxygen of keto group. From DFT calculations the Cu(II) and Fe(III) complexes behave as regular octahedral, while other complexes are distorted octahedral. The value of energy gap of the free ligand (ΔE = 0.3343 eV) is greater than all new complexes, so they are more reactive than free ligand, also the Fe(III) complex (ΔE = 0.0985 eV) is the most reactive complex, while Cu(II) complex (ΔE = 0.3219 eV) is the least reactive complex. The LMCT in case of Zr(IV) complex was resulted from transitions from HOMO-2 (62%), HOMO-1 (16%)and HOMO (25%), while the d-d transition in Fe(III) complex was resulted from HOMO-1(30%), HOMO-2(62%) and HOMO(30%). Also, the metal complexes exhibit antibacterial activity for Gram-positive and Gram-negative and antifungal activity. The Y(III) and Cu(II) complexes are highly significant for Escherichia coli and salmonella typhimurium.

Lanthanide coordination polymers based on multi-donor ligand containing pyridine and phthalate moieties: Structures, luminescence and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Feng, Xun [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Liu, Lang [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Wang, Li-Ya, E-mail: wlya@lynu.edu.cn [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang 473601 (China); Song, Hong-Liang; Qiang Shi, Zhi; Wu, Xu-Hong [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Ng, Seik-Weng [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 80203 (Saudi Arabia)

2013-10-15

A new family of five lanthanide-organic coordination polymers incorporating multi-functional N-hetrocyclic dicarboxylate ligand, namely, [Ln{sub 2}(Hdpp){sub 2}(dpp){sub 2}]{sub n}Ln=Pr(1), Eu(2), Gd(3), Dy(4), Er(5) (H{sub 2}dpp=1-(3, 4-dicarboxyphenyl) pyridin-4-ol) have been fabricated successfully through solvothermal reaction of 1-(3,4-dicarboxyphenyl)-4-hydroxypyridin-1-ium chloride with trivalent lanthanide salts, and have been characterized systematically. The complexes 1–5 are isomorphous and isostructural. They all feature three dimensional (3D) frameworks based on the interconnection of 1D double chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 4+} basic carboxylate as secondary building unit (SBU). The results of magnetic analysis shows the same bridging fashion of carboxylic group in this case results in the different magnetic properties occurring within lanthanide polymers. Moreover, the Eu(III) and Dy(III) complexes display characteristic luminescence emission in the visible regions. - Graphical abstract: A new family of lanthanide-organic frameworks incorporating multi-donor twisted ligand has been fabricated successfully, and has been characterized systematically. The complexes 1–5 are isostructural, and all feather three dimensional (3D) frameworks based on the interconnection of 1D double stride chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 2+} basic carboxylate as secondary building unit (SBU). Display Omitted - Highlights: • New family of lanthanide–organic coordination polymers incorporating multifunctional N-hetrocyclic dicarboxylate ligand has been fabricated. • They have been characterized systematically. • They all feather three dimensional frameworks based on the binuclear moiety of [Ln{sub 2}(Hdpp){sub 2}]{sup 2+}. • The Eu(III) and Dy(III) analogues exhibit intense photoluminescence.

Synergistic extraction of Th(IV) by 2-hydroxy-1-naphthaldehyde thiosemicarbazone and neutral donors

Energy Technology Data Exchange (ETDEWEB)

Banerjee, S.; Basu, S. [Nuclear and Analytical Chemistry Lab., Dept. of Chemistry, The Univ. of Burdwan, Burdwan (India)

2003-07-01

The extraction behaviour of Th(IV) from aqueous nitric acid medium employing 2-hydroxy-1-naphthaldehyde thiosemicarbazone has been studied in the presence of various donors, like trioctyl phosphine oxide (TOPO), calix[3]OH[3]OMe[6]arene, trioctyl amine (TOA), dimethyl sulphoxide (DMSO) in ethylacetate solvent. The constants (log k{sub ex}) for the binary complex in organic phase [Th(A)(NO{sub 3}){sub 3}], where A is the ligand, was found to be 3.99, which was by far the largest amongst the corresponding values known for the other thiosemicarbazones. The overall equilibrium constants (log K) for the ternary species [Th(A)TOPO(NO{sub 3}){sub 3}], [Th(A)TOA(NO{sub 3}){sub 3}], [Th(A)Calix[3]OH[3]OMe[6]arene(NO{sub 3}){sub 3}], [Th(A)DMSO(NO{sub 3}){sub 3}] were estimated to be 8.287, 8.862, 8.415, 6.921 respectively. The trend in equilibrium constants were in accordance with the substitution of the donor. The extraction of Th{sup 4+} by the ligand-donor combination was maximum at pH = 1 and extraction decreases with increase in pH. It has been found that the extent of extraction of Th{sup 4+} in the organic phase as the binary as well as ternary complex [Th(A)(NO{sub 3}){sub 3}] and [Th(A)(NO{sub 3}){sub 3}S], where S is the donor, increases with increase in the concentration of the ligand. Similar trend is obtained in the extraction by donors in absence of ligand. In case of ternary extraction, using different donors, amines are found to perform best compared to the other donors. The trend is as follows: TOA > calix[3]OH[3]OMe[6]arene > TOPO > DMSO. In addition, the effect of different diluents on extraction was also studied and the observed trend was methyl salicylate > ethyl acetate > methyl isobutyl ketone > ethyl benzoate. (orig.)

Synthesis and characterization of rhodium(I) complexes with P-N donor ligands and their catalytic application in transfer hydrogenation of carbonyl group

Energy Technology Data Exchange (ETDEWEB)

Barah, Geetika; Sarmah, Podma Poliov; Boruah, Devajani [Dept. of Chemistry, Dibrugarh University, Dibrugarh (India)

2015-04-15

Three rhodium(I) complexes of the types [Rh(COE)Cl(η{sup 2}-L)] (1a,1b) and [RhCl(η{sup 2}-L) (η{sup 1}-L)] (1c), where L = P⁓N donor ligands 2-[2-(diphenylphosphino) ethyl]pyridine, (PPh{sub 2}Etpy) (a), 2-(diphenylphosphino)pyridine (PPh{sub 2}py) (b), and 3-(diphenylphosphino)-1-propylamine (PPh{sub 2}(CH{sub 2}){sub 3}NH{sub 2}) (c), have been synthesized by reacting [Rh(coe){sub 2}Cl]{sub 2} with the respective ligands in 1:2 molar ratio for 1a, 1b and 1:4 molar ratio for 1c in DCM under refluxing condition. The complexes were characterized using different analytical techniques such as FT-IR, ESI(+) mass spectrometry, {sup 1}H and {sup 31}P{"1H} NMR spectrometry, conductivity measurements, and melting point determination. The synthesized complexes were found to exhibit good catalytic activity for the transfer hydrogenation of carbonyl compounds to corresponding alcohols with high conversion rate.

Synthesis, Spectral, Thermogravimetric, XRD, Molecular Modelling and Potential Antibacterial Studies of Dimeric Complexes with Bis Bidentate ON–NO Donor Azo Dye Ligands

Directory of Open Access Journals (Sweden)

Bipin Bihari Mahapatra

2013-01-01

Full Text Available The dimeric complexes of Co(II, Ni(II, Cu(II, Zn(II, Cd(II, and Hg(II with two new symmetrical ON–NO donor bis bidentate (tetradentate azo dye ligands, LH2 = 4,4′-bis(4′-hydroxyquinolinolinylazodiphenylsulphone, and L′H2 = 4,4′-bis(acetoacetanilideazodiphenylsulphone have been synthesized. The metal complexes have been characterised by elemental analytical, conductance, magnetic susceptibility, IR, electronic spectra, ESR, NMR, thermogravimetry, X-ray diffraction (powder pattern spectra, and molecular modelling studies. The Co(II and Ni(II complexes are found to be octahedral, Cu(II complexes are distorted octahedral, and a tetrahedral stereochemistry has been assigned to Zn(II, Cd(II, and Hg(II complexes. The thermogravimetric study indicates that compounds are quite stable. The energy optimized structures are proposed using the semiempirical ZINDO/1 quantum mechanical calculations. The potential antibacterial study of the ligands and some metal complexes has been made with one gram positive bacteria Staphylococcus aureus and one gram negative bacteria E. coli which gives encouraging results. Both the Co(II complexes are found to possess monoclinic crystal system.

Synthesis and Biological Activities on Metal Complexes of 2,5-Diamino-1,3,4-thiadiazole Derived from Semicarbazide Hydrochloride

Directory of Open Access Journals (Sweden)

Matthew A. Adebayo

2011-07-01

Full Text Available A bioactive ligand, 2,5-diamino-1,3,4-thiadiazole (L, derived from semicarbazide hydrochloride, and its metal complexes were prepared and characterized. The complexes were characterized using elemental, infra-red, ultraviolet/visible, magnetic moment, atomic absorption, thin layer chromatography and molar conductance measurements. The IR data revealed that the ligand (L behaved as a tridentate neutral ligand. It coordinated to the metal ion via sulphur and nitrogen of the amines. The molar conductance data reveal that the chelates are non-electrolytes. From the Ultraviolet/Visible spectra and magnetic moment data, the complexes were found to have octahedral geometrical structure. In vivo evaluation of the antimicrobial activities of the metal complexes and the ligands showed greater activity against some micro-organisms when compared to the parent compounds. The chelates do not show toxicity against the activities of enzymes from homogenates of liver, kidney and serum in experimental rats.

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.

A process of spent nuclear fuel treatment with the interim storage of TRU by use amidic extractants

International Nuclear Information System (INIS)

Tachimori, Shoichi; Suzuki, Shinichi; Sasaki, Yuji

2001-01-01

A new chemical process, ARTIST process, is proposed for the treatment of spent nuclear fuel. The main concept of the ARTIST process is to recover and stock separately all actinides, uranium and a mixture of transuranics, and to dispose fission products. The process composed of two main steps, a uranium exclusive isolation and a total recovery of transuranium elements (TRU); which copes with the nuclear non-proliferation measures, and additional processes. Both actinide products are solidified by calcination and allowed to the interim storage for future utilization. These separations are achieved by use of amidic extractants in accord with the CHON principle. The technical feasibility of the ARTIST process was explained by the experimental results of both the branched-alkyl monoamides in extracting uranium and suppressing the extraction of tetravalent actinides due to the steric effect and the diglycolic amide in thorough extraction of all TRU by tridentate coordination. When these TRU are requested to put into reactors, LWR or FBR, for power generation or the Accelerator-Driven System (ADS) for transmutation, lanthanides are to be removed from TRU by utilizing a soft nitrogen donor ligand. (author)

Oligomerization of ethylene catalysed by nickel complexes associated with nitrogen ligands in ionic liquids; Oligomerisation de l'ethylene catalysee par des complexes du nickel associes a des ligands azotes dans les liquides ioniques

Energy Technology Data Exchange (ETDEWEB)

Lecocq, V.

2003-09-01

We report here the use of a new class of catalytic systems based on a nickel active center associated with nitrogen ligands, such as di-imines, or imino-pyridines, for the oligomerization of ethylene in a biphasic medium using ionic liquids as the catalyst solvent. The nickel catalyst is immobilized in the ionic liquid phase in which the olefinic reaction products are poorly miscible. This biphasic system makes possible an easy separation and recycle of the catalyst. Numerous di-imine and imino-pyridine ligands with different steric and electronic properties have been synthesized and their corresponding nickel complexes isolated and characterized. Different ionic liquids, based on chloro-aluminates or non-chloro-aluminates anions, have also been prepared and characterized. The effect of the nature of the ligand, the ionic liquid, the nickel precursor and its mode of activation have been studied and correlated with the selectivity and activity of the transformation of ethylene. (author)

Electronic structure and properties of uranyl compounds. Problems of electron-donor conception

International Nuclear Information System (INIS)

Glebov, V.A.

1982-01-01

Comparison of the series of the ligand mutual substitution in the uranyl compounds with the ligand series of d-elements and with the uranyl ''covalent model'', is made. The data on ionization potentials of the ligand higher valent levels and on the structure of some uranyl nitrate compounds are considered. It is concluded that the mechanism of the ligand effect on the properties of uranyl grouping is more complex, than it is supposed in the traditional representations on the nature of electron-donor interactions in the uranyl compounds

The Ligand Substitution Reactions of Hydrophobic Vitamin B ...

African Journals Online (AJOL)

NJD

Vitamin B. 12. Derivatives. Reaction of Cobyric Acid. Heptapropyl Ester with Heterocyclic N-donor Ligands. Mohamed S.A. .... RESEARCH ARTICLE. M.S.A. Hamza ..... neutralized with NaHCO3 and treated with excess KCN to give. DCCbs-Pr.

Synthesis, spectroscopic and DNA binding ability of Co{sup II}, Ni{sup II}, Cu{sup II} and Zn{sup II} complexes of Schiff base ligand (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol. X-ray crystal structure determination of cobalt (II) complex

Energy Technology Data Exchange (ETDEWEB)

Yarkandi, Naeema H. [Chemistry Department, Faculty of Applied Science, Umm Al–Qura University, Makkah (Saudi Arabia); El-Ghamry, Hoda A., E-mail: helghamrymo@yahoo.com [Chemistry Department, Faculty of Applied Science, Umm Al–Qura University, Makkah (Saudi Arabia); Chemistry Department, Faculty of Science, Tanta University, Tanta (Egypt); Gaber, Mohamed [Chemistry Department, Faculty of Science, Tanta University, Tanta (Egypt)

2017-06-01

A novel Schiff base ligand, (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol (HL), has been designed and synthesized in addition to its metal chelates [Co(L){sub 2}]·l2H{sub 2}O, [Ni(L)Cl·(H{sub 2}O){sub 2}].5H{sub 2}O, [Cu(L)Cl] and [Zn(L)(CH{sub 3}COO)]. The structures of the isolated compounds have been confirmed and identified by means of different spectral and physicochemical techniques including CHN analysis, {sup 1}H &{sup 13}C NMR, mass spectral analysis, molar conductivity measurement, UV–Vis, infrared, magnetic moment in addition to TGA technique. The infrared spectral results ascertained that the ligand acts as monobasic tridentate binding to the metal centers via deprotonated hydroxyl oxygen, azomethine and imidazole nitrogen atoms. The UV–Vis, magnetic susceptibility and molar conductivity data implied octahedral geometry for Co(II) & Ni(II) complexes, tetrahedral for Zn(II) complex and square planar for Cu(II) complex. X-ray structural analysis of Co(II) complex 1 has been reported and discussed. Moreover, the type of interaction between the ligand & its complexes towards salmon sperm DNA (SS-DNA) has been examined by the measurement of absorption spectra and viscosity which confirmed that the ligand and its complexes interact with DNA via intercalation interaction as concluded from the values of binding constants (K{sub b}). - Highlights: • Synthesis of Co{sup II}, Ni{sup II}, Cu{sup II} and Zn{sup II} complexes of the Schiff base ligand based on 2-(aminomethyl)benzimidazole moiety. • The constitutions and structures of the ligand and complexes were elucidated. • Molecular structure of Co{sup II} complex was confirmed by single crystal X-ray diffraction method. • The ligand and its complexes interact with SS-DNA via intercalation mods.

Interactions between alkaline earth cations and oxo ligands. DFT study of the affinity of the Mg²+ cation for phosphoryl ligands.

Science.gov (United States)

da Costa, Leonardo Moreira; de Mesquita Carneiro, José Walkimar; Paes, Lilian Weitzel Coelho

2011-08-01

DFT (B3LYP/6-31+G(d)) calculations of Mg(2+) affinities for a set of phosphoryl ligands were performed. Two types of ligands were studied: a set of trivalent [O = P(R)] and a set of pentavalent phosphoryl ligands [O = P(R)(3)] (R = H, F, Cl, Br, OH, OCH(3), CH(3), CN, NH(2) and NO(2)), with R either bound directly to the phosphorus atom or to the para position of a phenyl ring. The affinity of the Mg(2+) cation for the ligands was quantified by means of the enthalpy for the substitution of one water molecule in the [Mg(H(2)O)(6)](2+) complex for a ligand. The enthalpy of substitution was correlated with electronic and geometric parameters. Electron-donor groups increase the interaction between the cation and the ligand, while electron-acceptor groups decrease the interaction enthalpy.

Synthesis, spectroscopic characterization, electrochemistry and biological evaluation of some metal (II) complexes with ONO donor ligand containing benzo[b]thiophene and coumarin moieties

Science.gov (United States)

Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

2014-09-01

Schiff base ligand 3-chloro-N‧-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzo[b]thiophene-2-carbohydrazide and its Cu(II), Co(II), Ni(II) and Zn(II) complexes were synthesized, characterized by elemental analysis and various physico-chemical techniques like, IR, 1H NMR, ESI-mass, UV-Visible, thermogravimetry - differential thermal analysis, magnetic measurements and molar conductance. Spectral analysis indicates octahedral geometry for all the complexes. Cu(II) complex have 1:1 stoichiometry of the type [M(L)(Cl)(H2O)2], whereas Co(II), Ni(II) and Zn(II) complexes have 1:2 stoichiometric ratio of the type [M(L)2]. The bonding sites are the oxygen atom of amide carbonyl, nitrogen of azomethine function and phenolic oxygen of the Schiff base ligand via deprotonation. The thermogravimetry - differential thermal analysis studies gave evidence for the presence of coordinated water molecules in the composition of Cu(II) complex which was further supported by IR measurements. All the complexes were investigated for their electrochemical activity, but only the Cu(II) complex showed the redox property. In order to evaluate the effect of antimicrobial potency of metal ions upon chelation, ligand and its metal complexes along with their respective metal chlorides were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The results showed that the metal complexes were found to be more active than free ligand. Ligand and its complexes were screened for free radical scavenging activity by DPPH method and DNA cleavage activity using Calf-thymus DNA (Cat. No-105850).

Interpretation of electronic spectra of ruthenium nitroso complexes with N-heterocyclic ligands

International Nuclear Information System (INIS)

Sizova, O.V.; Ivanova, N.V.; Lyubimova, O.O.; Nikol'skij, A.B.

2004-01-01

Relaying on ab initio and semiempirical CINDO/CI calculations of free ligands L and complexes trans-[Ru(NO)(NH 3 ) 4 (L)] 3+ (L=pyridine, pyrazine, nicotinamide, l-histidine, imidazole), electronic absorption spectra of nitroso complexes with nitrogen-containing heterocyclic ligands L have been analyzed. Spectral manifestations of strong covalent bond Ru-NO was pointed out and the conclusion was made about advisability of presentation of Ru and NO oxidation states in grouping RuNO 3+ as Ru(III) and NO 0 . Introduction of nitroso group into inner coordination sphere of Ru(II) complexes with nitrogen-containing heterocyclic ligands results in essential rearrangement of the entire structure and deprives ligands L of their ability to manifest chromophore properties [ru

Mixed-Ligand Complexes Of Nickel (II) With 2-Acetylpyridine ...

African Journals Online (AJOL)

The preparation and spectral properties of five nickel (II) mixed-ligands complexes (Ni [2-Actsc.Y]CI2), derived from 2-acetylpyridinethiosermicarbazones and some nitrogen/sulphur monodentate ligands such as thiophene, ammonia, picoline, pyridine and aniline are described. The complexes have been characterized on ...

Synthesis, crystal structure, antibacterial activity and theoretical studies on a novel mononuclear cobalt(II) complex based on 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand

Science.gov (United States)

Maghami, Mahboobeh; Farzaneh, Faezeh; Simpson, Jim; Ghiasi, Mina; Azarkish, Mohammad

2015-08-01

A cobalt complex was prepared from CoCl2·6H2O and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) in methanol and designated as [Co(tptz)(CH3OH)Cl2]·CH3OH·0.5H2O (1). It was characterized by several techniques including TGA analysis and FT-IR, UV-Vis and 1H NMR spectral studies. The crystal structure of 1 was determined by single-crystal X-ray diffraction. The Co(II) metal center in 1 is six coordinated with a distorted octahedral geometry. The tptz ligand is tridentate and coordinates to the cobalt through coplanar nitrogen atoms from the triazine and two pyridyl rings. Two chloride anions and a methanol molecule complete the inner coordination sphere of the metal ion. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single XRD data. The in vitro antibacterial activity of various tptz complexes of Co(II), Ni(II), Cu(II), Mn(II) and Rh(III) were evaluated against Gram-positive (Bacillus subtilis, Staphylococcus aureus and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Whereas all complexes exhibited good activity in comparison to standard antibacterial drugs, the inhibitory effects of complexes were found to be more than that of the parent ligand. Overall, the obtained results strongly suggest that the cobalt(II) complex is a suitable candidate for counteracting antibiotic resistant microorganisms.

Model studies of the Cu(B) site of cytochrome c oxidase utilizing a Zn(II) complex containing an imidazole-phenol cross-linked ligand.

Science.gov (United States)

Pesavento, Russell P; Pratt, Derek A; Jeffers, Jerry; van der Donk, Wilfred A

2006-07-21

Cytochrome c oxidase, the enzyme complex responsible for the four-electron reduction of O2 to H2O, contains an unusual histidine-tyrosine cross-link in its bimetallic heme a3-CuB active site. We have synthesised an unhindered, tripodal chelating ligand, BPAIP, containing the unusual ortho-imidazole-phenol linkage, which mimics the coordination environment of the CuB center. The ligand was used to investigate the physicochemical (pKa, oxidation potential) and coordination properties of the imidazole-phenol linkage when bound to a dication. Zn(II) coordination lowers the pKa of the phenol by 0.6 log units, and increases the potential of the phenolate/phenoxyl radical couple by approximately 50 mV. These results are consistent with inductive withdrawal of electron density from the phenolic ring. Spectroscopic data and theoretical calculations (DFT) were used to establish that the cationic complex [Zn(BPAIP)Br]+ has an axially distorted trigonal bipyramidal structure, with three coordinating nitrogen ligands (two pyridine and one imidazole) occupying the equatorial plane and the bromide and the tertiary amine nitrogen of the tripod in the axial positions. Interestingly, the Zn-Namine bonding interaction is weak or absent in [Zn(BPAIP)Br]+ and the complex gains stability in basic solutions, as indicated by 1H NMR spectroscopy. These observations are supported by theoretical calculations (DFT), which suggest that the electron-donating capacity of the equatorial imidazole ligand can be varied by modulation of the protonation and/or redox state of the cross-linked phenol. Deprotonation of the phenol makes the equatorial imidazole a stronger sigma-donor, resulting in an increased Zn-Nimd interaction and thereby leading to distortion of the axial ligand axis toward a more tetrahedral geometry.

Ruthenium sulfoxides structure and reactivity with nitrogen heterocyclic bases

International Nuclear Information System (INIS)

Oliveira, Denise de.

1990-01-01

Ruthenium (II) sulfoxides are compounds of great interest in oxidative catalysis and in chemotherapy. In order to contribute for the understanding of the chemistry and electronic structure of this class of compounds, it has been studied a series of [Ru Cl 2 (S-DMSO) 2 L x ] complexes, where x = 1 (polymeric compounds) or 2 (monomers) and L N-heterocyclic ligands (pyridine, pyrazine and imidazole derivatives). The nature of N-heterocyclic ligand and their coordination are of great relevance to the stability, spectroscopic and electrochemical characteristics of the complexes. The trans-interactions are extremely important in this series, influencing the strength of the Ru(II)-> S-DMSO and Ru(II)-> L π-back donation. The DMSO and L ligands are π-acceptors. The metal-> ligand π-back donation is strengthened when the ligand is trans to chloride, which is π-donor, due to trans-cooperative interactions of the type: π-donor -> Ru(II) π-acceptor. Another interesting aspect in the series of [Ru Cl 2 (S-DMSO) 2 L 2 ] complexes is the occurrence of dissociative equilibria in the solution, due to the existence of three types of ligands. It was observed that the trans-N isomer of 2,6-dimethyl pyrazine derivative undergoes thermal substitution, with preferential liabilization of the N-heterocyclic ligand. Chloride ion is the most inert ligand in this complex. (author). 145 refs., 76 figs., 21 tabs

Electronic and Spatial Structures of Water-Soluble Dinitrosyl Iron Complexes with Thiol-Containing Ligands Underlying Their Ability to Act as Nitric Oxide and Nitrosonium Ion Donors

OpenAIRE

Vanin, Anatoly F.; Burbaev, Dosymzhan Sh.

2011-01-01

The ability of mononuclear dinitrosyl iron commplexes (M-DNICs) with thiolate ligands to act as NO donors and to trigger S-nitrosation of thiols can be explain only in the paradigm of the model of the [Fe+(NO+)2] core ({Fe(NO)2}7 according to the Enemark-Feltham classification). Similarly, the {(RS−)2Fe+(NO+)2}+ structure describing the distribution of unpaired electron density in M-DNIC corresponds to the low-spin (S = 1/2) state with a d7 electron configuration of the iron atom and predomin...

Synthesis and characterisation of nitrogen poly-heterocyclic molecules using as selective complexing agents of metallic cations; Synthese et caracterisation de molecules polyheterocycliques azotees utilisables en tant que complexants selectifs de cations metalliques

Energy Technology Data Exchange (ETDEWEB)

Alphonse, F.A

2003-12-15

Separation of actinides (III) from lanthanides (III) is a crucial problem in the reprocessing of used nuclear fuels. Experimental results shown that soft donor extractants such as nitrogen polydentate heterocycles containing a NCCNCCN coordination site are potentials ligands for selective extraction of actinides (III). In those cases, two types of liquid-liquid extractions are employed: synergistic combination with lipophilic acid extractants and direct extraction. On the basis of the Hard and Soft Acids and Bases theory and basicity evaluation, new extractants were defined. We have first studied the synthesis of potential 1,3,5-triazine ligands designed for extraction in synergy with {alpha}-bromodecanoic acid. Secondly, we have examined the synthesis of bis-triazinyl-pyridine ligands for direct extraction studies. Extraction tests were carried out and perspectives of synthesis were deducted from those extraction results. (author)

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

Directory of Open Access Journals (Sweden)

Vladislav Vasilenko

2016-04-01

Full Text Available We report the modular synthesis of three different types of neutral κ2-P,N-ligands comprising an imine and a phosphine binding site. These ligands were reacted with rhodium, iridium and palladium metal precursors and the structures of the resulting complexes were elucidated by means of X-ray crystallography. We observed that subtle changes of the ligand backbone have a significant influence on the binding geometry und coordination properties of these bidentate P,N-donors.

Gamma radiolysis of the highly selective ligands CyMe_4BTBP and CyMe_4BTPhen: Qualitative and quantitative investigation of radiolysis product

International Nuclear Information System (INIS)

Schmidt, H.; Wilden, A.; Modolo, G.; Bosbach, D.; Santiago-Schuebel, B.; Hupert, M.; Svehla, J.; Gruner, B.; Ekberg, C.

2016-01-01

The highly selective nitrogen donor ligands CyMe_4BTBP and CyMe4_BTPhen where γ-irradiated under identical experimental conditions in 1-octanol with and without contact to nitric acid solution. Subsequently, solvent extraction experiments were carried out to evaluate the stability of the extractants against γ-radiation monitoring Am(III) and Eu(III) distribution ratios. Generally, decreasing distribution ratios with increasing absorbed dose were detected for both molecules. Furthermore, qualitative mass spectrometric analyses were performed and ligand concentrations were determined by HPLC-DAD after irradiation to investigate the radiolysis mechanism. An exponential decrease with increasing absorbed dose was observed for both ligands with a faster rate for CyMe_4BTPhen. Main radiolysis products indicated the addition of one or more diluent molecules (1-octanol) to the ligand via prior production of α-hydroxy-octyl radicals from diluent radiolysis. The addition of nitric acid during the irradiation lead to a remarkable stabilization of the system, as the extraction of Am(III) and Eu(III) did not change significantly over the whole examined dose range. Quantification of the remaining ligand concentration on the other hand showed decreasing concentrations with increasing absorbed dose. The stabilization of D values is therefore explained by the formation of 1-octanol addition products which are also able to extract the studied metal ions. (authors)

Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: synthesis, structure, electrochemistry and DFT calculations.

Science.gov (United States)

Al-Noaimi, Mousa; Awwadi, Firas F; Mansi, Ahmad; Abdel-Rahman, Obadah S; Hammoudeh, Ayman; Warad, Ismail

2015-01-25

The novel azoimine ligand, Ph-NH-N=C(COCH3)-NHPh(C≡CH) (H2L), was synthesized and its molecular structure was determined by X-ray crystallography. Catalytic hydration of the terminal acetylene of H2L in the presence of RuCl3·3H2O in ethanol at reflux temperature yielded a ketone (L1=Ph-N=N-C(COCH3)=N-Ph(COCH3) and an enol (L2=Ph-N=N-C(COCH3)=N-PhC(OH)=CH2) by Markovnikov addition of water. Two mixed-ligand ruthenium complexes having general formula, trans-[Ru(bpy)(Y)Cl2] (1-2) (where Y=L1 (1) and Y=L2 (2), bpy is 2.2'-bipyrdine) were achieved by the stepwise addition of equimolar amounts of (H2L) and bpy ligands to RuCl3·3H2O in absolute ethanol. Theses complexes were characterized by elemental analyses and spectroscopic (IR, UV-Vis, and NMR (1D (1)H NMR, (13)C NMR, (DEPT-135), (DEPT-90), 2D (1)H-(1)H and (13)C-(1)H correlation (HMQC) spectroscopy)). The two complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 604 mV vs. ferrocene/ferrocenium (Cp2Fe(0/+)) couple along with one electron ligand reduction at -1010 mV. The crystal structure of complex 1 showed that the bidentate ligand L1 coordinates to Ru(II) by the azo- and imine-nitrogen donor atoms. The complex adopts a distorted trans octahedral coordination geometry of chloride ligands. The electronic spectra of 1 and 1+ in dichloromethane have been modeled by time-dependent density functional theory (TD-DFT). Copyright © 2014 Elsevier B.V. All rights reserved.

Studies on coordination chemistry and biological activities of a nitrogen-sulfur donor ligand with lighter and heavier metal ions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Asmadi, A.; Talib, S.M.S.; Ali, A.M.; Crouse, K.A.

1999-05-01

Complexes of S-benzyldithiocarbazate (SBDTC) with lighter and heavier metals, viz., Cr(III), Fe(III), Sb(III), Zr(IV), Th(IV), and U(VI) have been prepared and characterized by elemental analyses, conductivity measurements, and spectral studies. The complexes were all prepared in alkaline media with the compositions of [Cr(SBDTCA) 3 ], [Fe(SBDTCA) 3 ], [Sb(SBDTCA) 3 ], [Sb(SBDTCA) 2 CI.H 2 O], [Zr(O)(SBDTCA) 2 .H 2 O], [Th(SBDTCA)(NO 3 ) 3 .H 2 O)], and [U(O) 2 (SBDTCA) 2 ]. The complexes were all hexa-coordinated with bidentate, uninegative chelation of the ligand. [Fe(SBDTCA) 3 ], [Sb(SBDTCA) 3 ] and [Sb(SBDTCA) 2 CI.H 2 O] were strongly effective against bacteria, Pseudomonas aeruginosa and Bacillus cereus giving clear inhibition zones. The compounds were poor antifungal. (author)

Ruthenium(II carbonyl compounds with the 4′-chloro-2,2′:6′,2′′-terpyridine ligand

Directory of Open Access Journals (Sweden)

Rajendhraprasad Tatikonda

2017-04-01

Full Text Available Two ruthenium carbonyl complexes with the 4′-chloro-2,2′:6′,2′′-terpyridine ligand (tpy-Cl, C15H10ClN3, i.e. [RuCl(tpy-Cl(CO2][RuCl3(CO3] (I [systematic name: cis-dicarbonylchlorido(4′-chloro-2,2′:6′,2′′-terpyridine-κ3Nruthenium(II fac-tricarbonyltrichloridoruthenate(II], and [RuCl2(tpy-Cl(CO2] (II [cis-dicarbonyl-trans-dichlorido(4′-chloro-2,2′:6′,2′′-terpyridine-κ2N1,N1′ruthenium(II], were synthesized and characterized by single-crystal X-ray diffraction. The RuII atoms in both centrosymmetric structures (I and (II display similar, slightly distorted octahedral coordination spheres. The coordination sphere in the complex cation in compound (I is defined by three N atoms of the tridentate tpy-Cl ligand, two carbonyl carbon atoms and one chlorido ligand; the charge is balanced by an octahedral [Ru(CO3Cl3]− counter-anion. In the neutral compound (II, the tpy-Cl ligand coordinates to the metal only through two of its N atoms. The coordination sphere of the RuII atom is completed by two carbonyl and two chlorido ligands. In the crystal structures of both (I and (II, weak C—H...Cl interactions are observed.

Bond of donor-acceptor interaction in metal-ligand system with energies of Fermi electrons

International Nuclear Information System (INIS)

Vlasov, Yu.V.; Khentov, V.Ya.; Velikanova, L.N.; Semchenko, V.V.

1993-01-01

Role of quantum nature of metal (W, Mo and others) in donor-acceptor interaction of metal salicylalaniline - aprotic solvent was discussed. The dependence of dissolution rate and activation energy of donor-acceptor interaction on electron energy was established

Studies on coordination chemistry and bioactivity of complexes of a bidentate oxygen-oxygen donor ligand, 1,2-dibenzoylhydrazine, with Cr3+, Co2+, Ni2+, Cu2+ and Zn2+ Ions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Lai Wee Wong; Crouse, Karen A.; Ali, A.M.; Yamin, B.M.; Fun, H.-K.

2003-08-01

A new bidentate ligand, 1,2-dibenzoylhydrazine (DBHz), with OO donor sequences, was prepared. Several complexes of DBHz containing Cr(JJI), Fe(UI), Co(U), Ni(JJ), Cu(II) and Zn(TJ) ions have been synthesized and characterized by CHN analyses, IR, molar conductivity and UV/Visible spectroscopic studies. All of the compounds were tested for their antibacterial, antifungal and anticancer properties. DBHz was very effective against Pseudomonas aeruginosa, Bacillus subtilis mutant and Bacillus subtilis wild type bacteria. It was also effective against Saccaromyces cereiviceae, Candida albicans, Candida albicans lypolytica and Aspergillus ochraceous fungi. The free ligand, DBHz, in particular, was strongly active against colon cancer cell lines (HT-29), with a CD 50 value of 2.5 /μg/ml. (author)

Interaction between alkaline earth cations and oxo-ligands. DFT study of the affinity of the Ca2+ cation for carbonyl ligands.

Science.gov (United States)

da Costa, Leonardo Moreira; Carneiro, José Walkimar de Mesquita; Romeiro, Gilberto Alves; Paes, Lilian Weitzel Coelho

2011-02-01

The affinity of the Ca(2+) ion for a set of substituted carbonyl ligands was analyzed with both the DFT (B3LYP/6-31+G(d)) and semi-empirical (PM6) methods. Two types of ligands were studied: a set of monosubstituted [O=CH(R)] and a set of disubstituted ligands [O=C(R)(2)] (R=H, F, Cl, Br, OH, OCH(3), CH(3), CN, NH(2) and NO(2)), with R either directly bound to the carbonyl carbon atom or to the para position of a phenyl ring. The interaction energy was calculated to quantify the affinity of the Ca(2+) cation for the ligands. Geometric and electronic parameters were correlated with the intensity of the metal-ligand interaction. The electronic nature of the substituent is the main parameter that determines the interaction energy. Donor groups make the interaction energy more negative (stabilizing the complex formed), while acceptor groups make the interaction energy less negative (destabilizing the complex formed).

Spectral characterization and DNA binding properties of lanthanide(III)

African Journals Online (AJOL)

Spectral data of complexes suggest that the ligand binds metal ion through pyridine- nitrogen, azomethine-nitrogen and amido-oxygen donor atoms. Electrochemical behaviour of metal complexes was investigated by using cyclic voltammetry. The complexes undergo quasi-reversible one electron reduction. The binding ...

A control on hydrophobic and hydrophilic interactions between HEWL and metal Schiff-base complexes comprising of different metal ions and ligands

Energy Technology Data Exchange (ETDEWEB)

Koley Seth, Banabithi; Ray, Aurkie; Basu, Samita, E-mail: samita.basu@saha.ac.in

2015-05-15

The structural effects of different copper(II) and nickel(II) Schiff base complexes on hen egg white lysozyme (HEWL) have been investigated through steady state and time resolved absorption and fluorescence, and circular dichroism spectroscopy. The Schiff base ligands with N{sub 4} donor atoms show both hydrophobic and hydrophilic interactions, however hydrophilic interaction prevails with ligands having N{sub 2}O{sub 2} donor atoms. Variation of metal ions from Cu{sup 2+} to Ni{sup 2+} with each type of Schiff base ligand increases the probability of hydrophilic over hydrophobic interactions, which supports their significance in regulating the binding affinity between HEWL and metal complexes. On photo-excitation the complexes comprising of Cu{sup 2+} ion instead of Ni{sup 2+} ion and ligands with N{sub 4} donor system rather than N{sub 2}O{sub 2} donor system, increases the probability of intersystem crossing to populate the corresponding triplet state as observed from laser flash photolysis study. The better binding affinity of nickel complexes with different selectivities compared to copper complexes towards HEWL emphasizes the potentiality of less explored nickel complexes in drug–protein interactions. - Highlights: • Ni{sup II} and Cu{sup II} -Schiff base complexes bind hen egg white lysozyme spontaneously. • Both hydrophobic and hydrophilic interactions are effective for N{sub 4} ligands. • For N{sub 2}O{sub 2} ligands the hydrophilic is predominant over hydrophobic interaction. • Binding affinity and selectivity of Ni{sup II}-complexes are better than Cu{sup II}-complexes. • Replacement of Cu{sup 2+} by Ni{sup 2+} in a ligand enhances chance of hydrophilic interaction.

Gamma radiolysis of the highly selective ligands CyMe{sub 4}BTBP and CyMe{sub 4}BTPhen: Qualitative and quantitative investigation of radiolysis product

Energy Technology Data Exchange (ETDEWEB)

Schmidt, H.; Wilden, A.; Modolo, G.; Bosbach, D. [Forschungszentrum Juelich GmbH, Institute of Energy and Climate Research IEK-6: Nuclear Waste Management, 52425 Juelich (Germany); Santiago-Schuebel, B.; Hupert, M. [Forschungszentrum Juelich GmbH, Central Institute for Engineering, Analytics - ZEA-3, 52425 Juelich (Germany); Svehla, J.; Gruner, B. [Institute of Inorganic Chemistry, Academy of Sciences, Hlavni 1001, 25068 Husinec-Rez (Czech Republic); Ekberg, C. [Department of Chemical and Biochemical Engineering, Chalmers University of Technology, 41296 Gothenburg (Sweden)

2016-07-01

The highly selective nitrogen donor ligands CyMe{sub 4}BTBP and CyMe4{sub B}TPhen where γ-irradiated under identical experimental conditions in 1-octanol with and without contact to nitric acid solution. Subsequently, solvent extraction experiments were carried out to evaluate the stability of the extractants against γ-radiation monitoring Am(III) and Eu(III) distribution ratios. Generally, decreasing distribution ratios with increasing absorbed dose were detected for both molecules. Furthermore, qualitative mass spectrometric analyses were performed and ligand concentrations were determined by HPLC-DAD after irradiation to investigate the radiolysis mechanism. An exponential decrease with increasing absorbed dose was observed for both ligands with a faster rate for CyMe{sub 4}BTPhen. Main radiolysis products indicated the addition of one or more diluent molecules (1-octanol) to the ligand via prior production of α-hydroxy-octyl radicals from diluent radiolysis. The addition of nitric acid during the irradiation lead to a remarkable stabilization of the system, as the extraction of Am(III) and Eu(III) did not change significantly over the whole examined dose range. Quantification of the remaining ligand concentration on the other hand showed decreasing concentrations with increasing absorbed dose. The stabilization of D values is therefore explained by the formation of 1-octanol addition products which are also able to extract the studied metal ions. (authors)

Studies on the mixed ligand complexes of copper(II involving a sulfa drug and some potentially bi or tridentate ligands under physiological conditions

Directory of Open Access Journals (Sweden)

S. Regupathy

2014-12-01

Full Text Available The stability constants of mixed ligand complexes formed in the Cu(II-sulfathiazole(stz(A-glycine(gly, dl-2-aminobutanoic acid(2aba, dl-3-aminobutanoic acid(3aba, 1,2-diaminopropane(dp, 1,3-diaminopropane(tp, dl-2,3-diaminopropanoic acid(dapa, dl-2,4-diaminobutanoic acid(daba, dl-2,5-diaminopentanoic acid(ornithine, orn(B systems have been determined pH-metrically at 37 °C and I = 0.15 mol dm−3 (NaClO4 using SCOGS program. Analysis of experimental data indicates the presence of CuABH, CuAB, CuAB2H2 or CuAB2 species. The Δlog K values demonstrate higher stabilities for the mixed ligand complexes compared to the binary analogues. The CuAB complexes with B = gly, 2aba, dapa & orn systems were isolated and characterized using micro analytical, magnetic moment, ESR, electrochemical studies, TG/DTA, power XRD and SEM analysis. Magnetic susceptibility and electronic spectral studies suggest square planar geometry for the CuAB complexes. The g values indicate that the unpaired electron lies in thedx2-y2 orbital. The TG/DTA studies reveal that the complexes are non hydrated and possesses high thermal stability. The powder XRD data suggest that the complex is microcrystalline. The antimicrobial activity and CT DNA cleavage studies of the complexes are also reported.

Characterization of donor states in ZnO

International Nuclear Information System (INIS)

Seghier, D.; Gislason, H.P.

2007-01-01

We performed electrical and optical measurements on as-grown ZnO which exhibits n-type conductivity. So far, neither the origin of the residual conductivity nor the electrical properties of the responsible defects is fully understood. We investigated shallow and deep donors in ZnO materials grown with pulsed laser injection using admittance spectroscopy. We identifed shallow donors with ionization energies as low as 15 meV which may be attributed to native defects. Annealing in nitrogen ambient enhances the conductivity by further lowering the ionization energy of the shallow donors. Using optically excited admittance spectroscopy we also found deep defects. They are strongly metastable and account for a significant part of the persistent photoconductivity in our ZnO materials

Liquid absorbent solutions for separating nitrogen from natural gas

Science.gov (United States)

Friesen, Dwayne T.; Babcock, Walter C.; Edlund, David J.; Lyon, David K.; Miller, Warren K.

2000-01-01

Nitrogen-absorbing and -desorbing compositions, novel ligands and transition metal complexes, and methods of using the same, which are useful for the selective separation of nitrogen from other gases, especially natural gas.

An enantiomerically pure siderophore type ligand for the diastereoselective 1 : 1 complexation of lanthanide(III ions

Directory of Open Access Journals (Sweden)

Markus Albrecht

2009-12-01

Full Text Available A facile synthesis of a highly preorganized tripodal enterobactine-type ligand 1a-H3 consisting of a chiral C3-symmetric macrocyclic peptide and three tridentate 2-amido-8-hydroxyquinoline coordinating units is presented. Complex formation with various metal ions (Al3+, Ga3+, Fe3+, La3+ and Eu3+ was investigated by spectrophotometric methods. Only in the case of La3+ and Eu3+ were well defined 1 : 1 complexes formed. On the basis of CD spectroscopy and DFT calculations the configuration at the metal centre of the La3+ complex was determined to show Λ helicity. The coordination compounds [(1aLn] presented should be prototypes for further lanthanide(III complexes with an enterobactine analogue binding situation.

Synthesis and structural studies of half-sandwich Cp* rhodium and ...

Indian Academy of Sciences (India)

A series of Cp*Rh and Cp*Ir complexes of various nitrogen and oxygen donor ligands were synthesized and characterized. Mono, bi and tetradentate ligands were used to synthesize mononuclear and dinuclear complexes. Schiff base derivatives of picolinic hydrazine and 5-aminoquinoline were used in thesynthesis of ...

Unexpected rearrangements in the synthesis of an unsymmetrical tridentate dianionic N-heterocyclic carbene

KAUST Repository

Despagnet-Ayoub, Emmanuelle; Miqueu, Karinne; Sotiropoulos, Jean-Marc; Henling, Lawrence M.; Day, Michael W.; Labinger, Jay A.; Bercaw, John E.

2013-01-01

Starting from the same ethylenediamine species, three valuable carbene precursors were synthesized under differing conditions: a tridentate dianionic N-heterocyclic carbene bearing an aniline, a phenol and a central dihydroimidazolium salt, its benzimidazolium isomer by intramolecular rearrangement and a dicationic benzimidazolium-benzoxazolium salt by changing the Brønsted acid from HCl to HBF4. A DFT study was performed to understand the rearrangement pathway. The structure of a bis[(NCO)carbene] zirconium complex was determined. © 2013 The Royal Society of Chemistry.

Ligand-controlled, tunable silver-catalyzed C-H amination.

Science.gov (United States)

Alderson, Juliet M; Phelps, Alicia M; Scamp, Ryan J; Dolan, Nicholas S; Schomaker, Jennifer M

2014-12-03

The development of readily tunable and regioselective C-H functionalization reactions that operate solely through catalyst control remains a challenge in modern organic synthesis. Herein, we report that simple silver catalysts supported by common nitrogenated ligands can be used to tune a nitrene transfer reaction between two different types of C-H bonds. The results reported herein represent the first example of ligand-controlled and site-selective silver-promoted C-H amination.

A series of luminescent Re(I) complexes with electron-donor/acceptor moieties: Synthesis, characterization, and photoluminescence

International Nuclear Information System (INIS)

Ge Hu; Qing She; Lei Guo

2012-01-01

In this paper, we synthesize three Re(I) complexes of Re(CO) 3 (PPO)Br, Re(CO) 3 (PTO)Br, and Re(CO) 3 (PBI)Br, where PPO=2-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole, PTO=2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole, PBI=2-(pyridin-2-yl)-1H-benzo[d]imidazole. Their single crystals and photophysical properties are measured and discussed in detail. The correlation between ligand structure and corresponding PL characteristics of Re(I) complex has been investigated. It is found that a ligand with strong electron-donor can efficiently increase both absorption and emissive energy of Re(I) complex. In addition, electron-rich ligand can increase the electron density of the complex and thus enhance the oscillator strength of electronic transition, improving the photoluminescence performance. - Highlights: ► Three novel phosphorescent Re(I) complexes are synthesized. ► Molecular structures, photophysical, and electronic properties are studied. ► Strong electron-donor can increase emissive energy. ► Electron-rich ligand can enhance the oscillator strength of electronic transition.

Synthesis and spectroscopic characterization of some lanthanide(III nitrate complexes of ethyl 2-[2-(1-acetyl-2-oxopropylazo]-4,5-dimethyl-3-thiophenecarboxyate

Directory of Open Access Journals (Sweden)

CHEMPAKAM JANARDHANAN ATHIRA

2011-02-01

Full Text Available Ethyl 2-[2-(1-acetyl-2-oxopropylazo]-4,5-dimethyl-3-thiophenecarboxyate was synthesized by coupling diazotized ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate with acetylacetone. Based on various spectral studies and elemental analysis, an intramolecularly hydrogen-bonded azo-enol structural form was assigned for the ligand. This ligand is versatile in forming a series of lanthanide(III complexes, viz., lanthanum(III, cerium(III, praseodymium(III, neodymium(III, samarium(III and gadolinium(III, which were characterized through various spectral studies, elemental analysis, magnetic susceptibility measurements, molar conductance and thermal analysis. The spectral data revealed that the ligand acted as a neutral tridentate, coordinating to the metal ion through one of the azo nitrogen atoms, the ester carbonyl and the enolic oxygen of the acetylacetone moiety, without deprotonation. Molar conductance values adequately supported their non-electrolytic nature. The ligand and lanthanum(III complex were subjected to X-ray diffraction studies. In addition, the lanthanum(III complex underwent a facile transesterification reaction on refluxing with methanol for a long period. The thermal behaviour of the lanthanum(III complex was also examined

Los Alamos National Laboratory Request for Proposals: Trident Laser System (TLS) Redeployment and Life Extension, October 5, 2016

Energy Technology Data Exchange (ETDEWEB)

Stringer, Steven F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-10-04

In May 2016, LANS announced that the Trident Laser Facility would cease operating effective September 15, 2016. That date was subsequently extended. The current plan is to operate for an additional, limited period in early CY 2017, and to leverage that activity to provide a training opportunity to the party that will redeploy the TLS. The TLS will then be disassembled and packaged for shipping to the new site, where it may be reconstituted and continue to be used by the physics research community. It is LANS’ intent that Trident will be sited with an organization that will supply its own funding for TLS installation, calibration, and lifecycle operation. Ideally, the receiving party will plan to upgrade TLS with new capability. The equipment to be transferred includes the laser, its power supply, target station and chamber, and a suite of diagnostic instrumentation. Under a Joint Use Agreement it is anticipated that all equipment will remain property of the Laboratory and subject to on-site configuration verification.

Thioether-ligated iron(ii) and iron(iii)-hydroperoxo/alkylperoxo complexes with an H-bond donor in the second coordination sphere†

OpenAIRE

Widger, Leland R.; Jiang, Yunbo; McQuilken, Alison C.; Yang, Tzuhsiung; Siegler, Maxime A.; Matsumura, Hirotoshi; Moënne-Loccoz, Pierre; Kumar, Devesh; de Visser, Sam P.; Goldberg, David P.

2014-01-01

The non-heme iron complexes, [FeII(N3PySR)(CH3CN)](BF4)2 (1) and [FeII(N3PyamideSR)](BF4)2 (2), afford rare examples of metastable Fe(iii)-OOH and Fe(iii)-OOtBu complexes containing equatorial thioether ligands and a single H-bond donor in the second coordination sphere. These peroxo complexes were characterized by a range of spectroscopic methods and density functional theory studies. The influence of a thioether ligand and of one H-bond donor on the stability and spectroscopic properties of...

Crystal structure of bis[μ-S-hexyl 3-(2-oxidobenzylidenedithiocarbazato-κ4O,N3,S:O]dicopper(II

Directory of Open Access Journals (Sweden)

M. S. Begum

2015-12-01

Full Text Available The title compound, [Cu2(C14H18N2OS22], is a binuclear copper(II complex of an oxybenzylidenedithiocarbazate ligand. The ligand coordinates in a tridentate manner through N-, S- and O-donor atoms. Each O atom also bridges to a second CuII ion to form the binuclear species. It has a central Cu2O2 rhomboid moiety and a metal-to-metal separation of 2.9923 (6 Å. In the crystal, the binuclear complexes stack along the a axis with all the hexyl chains located side-by-side, forming a hydrophobic region. The complexes are linked via C—H...N hydrogen bonds, forming chains along the c-axis direction. One CuII atom has the S atom of a symmetry-related complex located approximately in the apical position at 2.9740 (11 Å. This weak interaction links the chains to form slabs parallel to the ac plane.

Role of N-Donor Sterics on the Coordination Environment and Dimensionality of Uranyl Thiophenedicarboxylate Coordination Polymers

Energy Technology Data Exchange (ETDEWEB)

Thangavelu, Sonia G. [Department; Butcher, Ray J. [Department; Cahill, Christopher L. [Department

2015-06-09

Thiophene 2,5-dicarboxylic acid (TDC) was reacted with uranyl acetate dihydrate and one (or none) of six N-donor chelating ligands (2,2'-bipyridine (BPY), 4,4'-dimethyl-2,2'-bipyridine (4-MeBPY), 5,5'-dimethyl-2,2'-bipyridine (5-MeBPY), 6,6'-dimethyl-2,2'-bipyridine (6-MeBPY), 4,4',6,6'-tetramethyl-2,2'-bipyridine (4,6-MeBPY), and tetrakis(2-pyridyl)pyrazine (TPPZ) to result in the crystallization of seven uranyl coordination polymers, which were characterized by their crystal structures and luminescence properties. The seven coordination polymers, Na2[(UO2)2(C6H2O4S)3]·4H2O (1), [(UO2)4(C6H2O4S)5(C10H8N2)2]·C10H10N2·3H2O (2), [(UO2)(C6H2O4S)(C12H12N3)] (3), [(UO2)(C6H2O4S)(C12H12N3)]·H2O (4), [(UO2)2(C6H2O4S)3]·(C12H14N2)·5H2O (5), [(UO2)3(CH3CO2)(C6H2O4S)4](C14H17N2)3·(C14H16N2)·H2O (6), and [(UO2)2(C6H2O4S)3](C24H18N6) (7), consist of either uranyl hexagonal bipyramidal or pentagonal bipyramidal coordination geometries. In all structures, structural variations in the local and global structures of 1–7 are influenced by the positions (or number) of methyl groups or pyridyl rings on the N-donor species, thus resulting in a wide diversity of structures ranging from single chains, double chains, or 2-D sheets. Direct coordination of N-donor ligands to uranyl centers is observed in the chain structures of 2–4 using BPY, 4-MeBPY, and 5-MeBPY, whereas the N-donor species participate as guests (as either neutral or charge balancing species) in the chain and sheet structures of 5–7 using 6-MeBPY, 4,6-MeBPY, and TPPZ, respectively. Compound 1 is the only structure that does not contain any N-donor ligands and thus crystallizes as a 2-D interpenetrating sheet. The luminescent properties of 1–7 are influenced by the direct coordination or noncoordination of N-donor species to uranyl centers. Compounds 2–4 exhibit typical UO22+ emission upon direct coordination of N-donors, but its absence is observed in 1

Spectroscopic studies of some lanthanide(III nitrate complexes synthesized from a new ligand 2,6-bis-(salicylaldehyde hydrazone-4-chlorophenol

Directory of Open Access Journals (Sweden)

A.S. Sall

2003-06-01

Full Text Available The ligand 2,6-bis-(salicylaldehydehydrazone-4-chlorophenol (H5L and its binuclear lanthanide(III nitrate complexes {[Ln2(H4L3(NO3](NO32.mH2O} where Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb and Y, have been synthesized. The complexes were characterized by chemical analysis, conductance, magnetic moment measurements and infrared spectra. Infrared study indicates that the ligand behaves both as neutral and ionic O donors and as neutral N donors.

Synthesis, structural, spectroscopic and biological studies of Schiff base complexes

Science.gov (United States)

Diab, M. A.; El-Sonbati, A. Z.; Shoair, A. F.; Eldesoky, A. M.; El-Far, N. M.

2017-08-01

Schiff base ligand 4-((pyridin-2- yl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (PDMP) and its complexes were prepared and characterized on the basis of elemental analysis, IR, mass spectra and thermogravimetric analysis. All results confirm that the complexes have 1:1 (M: PMDP) stoichiometric formula [M(PMDP)Cl2H2O ] (M = Cu(II), Co(II), Ni(II) and Mn(II)), [Cd(PMDP)Cl2] and the ligand behaves as a bi/tridentate forming five-membered chelating ring towards the metal ions, bonding through azomethine nitrogen/exocyclic carbonyl oxygen, azomethine pyridine nitrogen and exocyclic carbonyl oxygen. The shift in the band positions of the groups involved in coordination has been utilized to estimate the metal-nitrogen and/or oxygen bond lengths. The complexes of Co(II), Ni(II) and Cu(II) are paramagnetic and the magnetic as well as spectral data suggest octahedral geometry, whereas the Cd(II) complex is tetrahedral. The XRD studies show that both the ligand and its metal complexes (1 and 3) show polycrystalline with crystal structure. Molecular docking was used to predict the binding between PMDP ligand and the receptors. The corrosion inhibition of mild steel in 2 M HCl solution by PDMP was explored utilizing potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and (EFM) electrochemical frequency modulation method. Potentiodynamic polarization demonstrated that PDMP compound is mixed-type inhibitor. EIS spectra exhibit one capacitive loop and confirm the protective ability. The percentage of inhibition efficiency was found to increase with increasing the inhibitor concentration.

Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

International Nuclear Information System (INIS)

Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

2015-01-01

A successive anchoring of Ti(NMe 2 ) 4 , cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, 13 C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands. - Graphical abstract: The ligand-tailored silica supported “single site” titanium complexes were synthesized by SOMC strategy and fully characterized. Their catalytic activity were evaluated by benzaldehyde silylcyanation. - Highlights: • Single-site silica supported Ti active species was prepared by SOMC technique. • O-donor ligand tailored Ti surface species was synthesized. • The surface species was characterized by XPS, 13 C CP-MAS NMR, XANES etc. • Catalytic activity of the Ti active species in silylcyanation reaction was evaluated

Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

Energy Technology Data Exchange (ETDEWEB)

Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

2015-01-15

A successive anchoring of Ti(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands. - Graphical abstract: The ligand-tailored silica supported “single site” titanium complexes were synthesized by SOMC strategy and fully characterized. Their catalytic activity were evaluated by benzaldehyde silylcyanation. - Highlights: • Single-site silica supported Ti active species was prepared by SOMC technique. • O-donor ligand tailored Ti surface species was synthesized. • The surface species was characterized by XPS, {sup 13}C CP-MAS NMR, XANES etc. • Catalytic activity of the Ti active species in silylcyanation reaction was evaluated.

Synthesis, crystal structures, and thermal and spectroscopic properties of two Cd(II) metal-organic frameworks with a versatile ligand

Energy Technology Data Exchange (ETDEWEB)

Li, Jia-Ming; He, Kun-Huan; Shi, Zhong-Feng [Qinzhou Univ. (China). Guangxi Colleges and Univs. Key Lab. of Beibu Gulf Oil and Natural Gas Resource Effective Utilization; Gao, Hui-Yuan; Jiang, Yi-Min [Guangxi Normal Univ., Guilin (China). Key Lab. for the Chemistry and Molecular Engineering of Medicinal Resources

2016-11-01

Two new metal-organic frameworks, namely, [Cd(L)(H{sub 2}O)]{sub n} (1) and {[Cd_0_._5(L)(4,4"'-bipy)_0_._5][Cd_0_._5(H_2O)(4,4"'-bipy)_0_._5].H_2O}{sub n} (2), where H{sub 2}L = N-pyrazinesulfonyl-glycine and 4,4{sup '}-bipy = 4,4{sup '}-bipyridine, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric, and photoluminescent analysis. X-ray diffraction crystallographic analyses indicate that 1 displays a distorted octahedral metal coordination in a 3-connected (4, 8{sup 2}) topology, while the molecular structure of 2 has a 4-connected (4, 4) topology with two perfectly octahedrally coordinated Cd centers. The L{sup 2-} ligand serves as a N,N,O-tridentate, μ{sub 2}-pyrazine-bridging, and μ{sub 2}-carboxylate-bridging ligand in 1, and as a N,O-bidentate and μ{sub 2}-carboxylate-bridging ligand in 2. In the crystal, a 3D supramolecular architecture is formed by O-H..O hydrogen bond interactions in 1, but through O-H..O as well as π..π stacking in 2. The two compounds show intense fluorescence in the solid state at room temperature.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 12. Synthesis, characterization, X-ray crystal structure, ... The Cu(II) center is coordinated by two oxygen and one nitrogen donors of L2− and nitrogen atoms of the heterocyclic group. Electrochemical studies of the Cu(II) complex showed shifts in the ligand ...

A series of Cadmium(II) complexes with 2-substituted terephthalate building block and N-Donor co-ligands: Structural diversity and fluorescence properties

Science.gov (United States)

Ren, Yixia; Zhou, Shanhong; Wang, Zhixiang; Zhang, Meili; Wang, Jijiang; Cao, Jia

2017-11-01

Four new Cd(II) complexes have been prepared based on 1,2,4-trimellitic acid (H3tma) and monosodium 2-sulfoterephthalate (2-NaH2stp), formulated as [Cd2(Htma)2 (dpp)2(H2O)] (1), [Cd3 (tma)2 (2,4-bipy)4(H2O)2] (2), [Cd (2-Hstp) (2,2'-bipy)2]·2H2O (3) and [Cd (2-Hstp) (2,4-bipy) (H2O)2] (4) (dpp = dipyrido [3,2-a:2‧,3'-c] phenazine, 2,4-bipy = 2,4-bipyridine, 2,2'-bipy = 2,2'- bipyridine) by hydrothermal method. X-ray diffraction structural analyses show all these complexes crystallized in triclinic crystal system of Pī space group, but their structures are diverse. Complex 1 exhibits an infinite one-dimensional chain featuring the left- and right-handed stranded chains interweaved each other. For 2, the two-dimensional network is constructed by one-dimensional ladder-like chain linked by Cd2 ions. In complex 3, the cadmium ion is surrounded with one 2-Hstp2- anion and two 2,2'-bipy molecules. Complex 4 is also a discrete structure based on a metallic dimer unit. In all these complexes, the N-donor co-ligands take the important roles in the assembly of three-dimensional supramolecular structures. The fluorescence properties of complexes 1-4 could be assigned to the π - π* transition of organic ligands.

Natural bond orbital analysis of molecular interactions: Theoretical study of W(CO)5 complexes with E(PH3)2 and NHEMe ligands (E=C, Si, Ge, Sn, Pb)

International Nuclear Information System (INIS)

Nguyen Thi Ai Nhung; Huynh Thi Phuong Loan; Duong Tuan Quang; Pham Van Tat

2014-01-01

The complexes with ligands carbodiphosphorane-analogues (called tetrylones) [(CO) 5 W-{E(PH 3 ) 2 }] (W5-EP 2 ) and N-heterocyclic carbene-analogues (called tetrylenes) [(CO) 5 W-{NHE Me }] (W5-NHE Me ) when E=C-Pb have been studied using natural bond orbital (NBO) method. The NBO analysis provides a consistent picture of the chemical bonding is two entire families of transition metal complexes of tetrylone and tetrylene ligands in term of donor-acceptor interactions, showing the correlation of these interactions with Wiberg bond indies (WBI), natural partial charges, and the energetically highest lying occupied molecular orbitals for σ and π orbitals of free ligands E(PH 3 ) 2 and NHE Me . Analysis of the bonding situation reveals that in E(PH 3 ) 2 and NHE Me ligands, the energy level of the π orbital rises, whereas that of the σ orbital decreases as atom E becomes heavier. The complexes with head-on-bonded ligands have (CO) 5 W←E donation which comes from the σ-lone-pair orbital of E(PH 3 ) 2 and NHE Me where E=C for tetrylones and E=C, Si, Ge for tetrylenes, whereas the (CO) 5 W←E donation in the side-on bonded complexes when E becomes heavier arises from the π-lone-pair orbital of E(PH 3 ) 2 and NHE Me ligands which is the HOMO of the free ligands. This makes the heavier adducts of tetrylones and tetrylenes become stronger donors than the lighter systems. The NBO analysis suggests that the E(PH 3 ) 2 ligands are strong σ-donors and strong π-acceptors while the NHE Me ligands are strong σ-donors and weak π-acceptors. This is possible for tetrylones that have two lone-pair orbitals available for donation, whereas the tetrylenes have only one lone-pair orbital available for donation. (author)

Synthesis, characterization and anticancer activities of two lanthanide(III) complexes with a nicotinohydrazone ligand

Science.gov (United States)

Xu, Zhou-Qin; Mao, Xian-Jie; Jia, Lei; Xu, Jun; Zhu, Tao-Feng; Cai, Hong-Xin; Bie, Hong-Yan; Chen, Ru-Hua; Ma, Tie-liang

2015-12-01

Two isostructural acylhydrazone based complexes, namely [Ce(penh)2(H2O)4](NO3)3·4H2O (1) and [Sm(penh)2(NO3)2](NO3)·C2H5OH (2) (penh = 2-acetylpyridine nicotinohydrazone), have been obtained and characterized by physico-chemical and spectroscopic methods. The ten-coordinated lanthanide metal ion in each complex is surrounded by two independent tridentate neutral acylhydrazones with two ON2 donor sets. The other four coordination oxygen atoms are from four water molecules and two bidentate nitrate anions for complexes 1 and 2, respectively, thus giving distorted bicapped square antiprism geometry. Both complexes have excellent antitumor activity towards human pancreatic cancer (PATU8988), human colorectal cancer (lovo) and human gastric cancer(SGC7901) cell line. Furthermore, the cell apoptosis of complex 1 is detected by AnnexinV/PI flow cytometry.

Synthesis and properties of mixed-ligand ruthenium(II) complexes containing 2-(2-pyridyl)-benzimidazole and related ligands

International Nuclear Information System (INIS)

Haga, Masaaki; Tanaka, Toshio.

1979-01-01

Mixed-ligand ruthenium(II) complexes of the [Ru(bpy) 2 L]sup(n+) (ClO 4 )sub(n) type, where bpy= 2,2'-bipyridine; L= 2-(2-pyridyl)-benzimidazole (PBImH) when n= 2, and L= 2-(2-pyridyl)-benzimidazolate (PBIm) and 2-(o-hydroxyphenyl)-benzimidazole (OBImH) when n= 1, were prepared. Anodic peak potentials and ruthenium-to-bipyridine charge transfer bands of these complexes are rationalized in terms of the donor ability of L. (author)

Synthesis and properties of mixed-ligand ruthenium(II) complexes containing 2-(2-pyridyl)-benzimidazole and related ligands

Energy Technology Data Exchange (ETDEWEB)

Haga, M [Mie Univ., Tsu (Japan); Tanaka, T

1979-07-01

Mixed-ligand ruthenium(II) complexes of the (Ru(bpy)/sub 2/L)sup(n+) (ClO/sub 4/)sub(n) type, where bpy= 2,2'-bipyridine; L= 2-(2-pyridyl)-benzimidazole (PBImH) when n= 2, and L= 2-(2-pyridyl)-benzimidazolate (PBIm) and 2-(o-hydroxyphenyl)-benzimidazole (OBImH) when n= 1, were prepared. Anodic peak potentials and ruthenium-to-bipyridine charge transfer bands of these complexes are rationalized in terms of the donor ability of L.

A theoretical investigation on the neutral Cu(I) phosphorescent complexes with azole-based and phosphine mixed ligand

Science.gov (United States)

Ding, Xiao-Li; Shen, Lu; Zou, Lu-Yi; Ma, Ming-Shuo; Ren, Ai-Min

2018-04-01

A theoretical study on a series of neutral heteroleptic Cu(I) complexes with different azole-pyridine-based N^N ligands has been presented to get insight into the effect of various nitrogen atoms in the azole ring on photophysical properties. The results reveal that the highest occupied molecular orbital (HOMO) levels and the emission wavelengths of these complexes are mainly governed by the nitrogen atom number in azole ring. With the increasing number of nitrogen atom , the electron density distribution of HOMO gradually extend from the N^N ligand to the whole molecule, meanwhile, the improved contribution from Cu(d) orbits in HOMO results in an effective mixing of various charge transfermodes, and hence, the fast radiative decay(kr) and the slow non-radiative decay rate(knr) are achieved. The photoluminescence quantum yield (PLQY) show an apparent dependence on the nitrogen atom number in the five-membered nitrogen heterocycles. However, the increasing number of nitrogen atoms is not necessary for increasing PLQY. The complex 3 with 1,2,4-triazole-pyridine-based N^N ligands is considered to be a potential emitter with high phosphorescence efficiency. Finally, we hope that our investigations will contribute to systematical understanding and guiding for material molecular engineering.

Polarographic and potentiometric studies on some binary and ternary complex systems of dioxouranium(VI)

International Nuclear Information System (INIS)

Janarthanam, M.; Sivasankar, B.; Rengaraj, K.; Nair, M.S.

1995-01-01

The relative coordinating abilities of donor sites in the potentially tridentate ligands viz., asparagine, glutamine, aspartic acid and glutamic acid towards uranyl ion have been investigated by polarographic and pH-metric techniques. The metal ion forms 1:2 complexes under polarographic conditions. However, only 1:1 complex is observed under pH-metric conditions, where 1:2 complexes do not proceed due to extensive hydrolysis of the metal ion. The relative variations of ΔE 1/2 with pH and ligand concentration supported by conductometric titration data indicate that the primary amino groups in the amino acids are not involved in coordination with uranyl ion. Further, the amide groups in asparagine and glutamine also do not participate in coordination thus rendering these ligands unidentate. In aspartic and glutamic acid complexes, seven- and eight- membered chelate rings are formed involving two terminal carboxyl groups. The mixed ligand complex equilibria of uranyl ion involving aspartic acid/glutamic acid as primary ligands (A) and maleic acid, malonic acid, succinic acid and lactic acid as secondary ligands (B) have also been studied by computer based numerical evaluation of pH titration data. The concentration profiles have indicated the favorability of the formation of ternary complexes in general as reflected in the Δlog K values. (author). 10 refs., 1 fig., 1 tab

Halide/pseudohalide complexes of cadmium(II) with benzimidazole: Synthesis, crystal structures and fluorescence properties

Science.gov (United States)

Zhao, Hai-Yan; Yang, Fu-Li; Li, Na; Wang, Xiao-Jing

2017-11-01

Two new dinuclear Cd(II) complexes, [CdL1Cl2]2·H2O (1) and [CdL1(N3)2]2·CH3OH (2) and one dicyanamide bridged one-dimensional polynuclear network [CdL1(μ1,5-dca)dca]n (3) of the potentially tridentate NNN-donor Schiff base 2-((1H-benzimidazol-2-yl-ethylimino)-methyl)pyridine (L1) and another dinucler Cd(II) complex [CdL2Cl(dca)]2 (4) of a similar NNN-donor Schiff base ligand 2-((1H-benzimidazol-2-yl-propylimino)-methyl)pyridine (L2), have been synthesized and characterized by elemental analyses, IR and single crystal X-ray crystallography. The ligands L1 and L2 are [1 + 1] condensation products of pyridine-2-carbaldehyde with 2-aminoethyl-1H-benzimidazole and 2-aminopropyl-1H-benzimidazole, respectively. In the complexes 1 and 4 the two Cd(II) centers are held together by the bridged chloride ligands, while in 2 the two Cd(II) centers are bridged by μ1,1-azide ions. Complex 3 has a one-dimensional infinite chain structure in which Cd(II) ions are bridged by single dicyanamide groups in end-to-end fashion. All the metal centers have a distorted octahedral geometry and H-bonding or π⋯π interactions are operative to bind the complex units in the solid state. Furthermore, these complexes have been investigated by thermogravimetric analyses and fluorescence spectra.

Characterization and application of a laser-driven intense pulsed neutron source using Trident

Energy Technology Data Exchange (ETDEWEB)

Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-08-25

A team of Los Alamos researchers supported a final campaign to use the Trident laser to produce neutrons, contributed their multidisciplinary expertise to experimentally assess if laser-driven neutron sources can be useful for MaRIE. MaRIE is the Laboratory’s proposed experimental facility for the study of matter-radiation interactions in extremes. Neutrons provide a radiographic probe that is complementary to x-rays and protons, and can address imaging challenges not amenable to those beams. The team's efforts characterize the Laboratory’s responsiveness, flexibility, and ability to apply diverse expertise where needed to perform successful complex experiments.

Template synthesis, characterization and antimicrobial activity of some new complexes with isonicotinoyl hydrazone ligands

Directory of Open Access Journals (Sweden)

LIVIU MITU

2009-09-01

Full Text Available Complexes of Cu(II, Ni(II, Co(II with the 9-anthraldehyde iso-nicotinoyl hydrazone ligand (HL1 and the 3,5-di-tert-butyl-4-hydroxy-benzaldehyde isonicotinoyl hydrazone ligand (H2L2 were synthesized by the template method. The complexes were characterized by analytical analysis, IR, UV-Vis and ESR spectroscopy, magnetic measurements, conductometry and thermal analysis and the two ligands by 1H-NMR spectroscopy. From the elemental analysis, 1:2 (metal:ligand stoichiometry for the complexes of Cu(II, Ni(II with the ligands HL1 and H2L2 and 1:1 (metal:ligand stoichiometry for the complex of Co(II with the ligand HL1 are proposed. The molar conductance data showed that the complexes are non-electrolytes. The magnetic susceptibility results coupled with the electronic and ESR spectra suggested a distorted octahedral geometry for the complexes Ni(II/HL1, Ni(II/H2L2 and Cu(II/H2L2, a tetrahedral stereochemistry for the complex Cu/HL1 and a square-planar geometry for the complex Co/HL1. The IR spectra demonstrated the bidentate coordination of the ligands HL1 and H2L2 by the O=C amide oxygen and the azomethine nitrogen, as well as monodentate coordination of the ligand HL1 by the azomethine nitrogen in the Cu(IIcomplex. The antibacterial activity of the ligands and their metallic complexes were tested against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae.

Steric and Stereochemical Modulation in Pyridyl- and Quinolyl-Containing Ligands

Directory of Open Access Journals (Sweden)

Zhaohua Dai

2016-12-01

Full Text Available Nitrogen-containing pyridine and quinoline are outstanding platforms on which excellent ionophores and sensors for metal ions can be built. Steric and stereochemical effects can be used to modulate the affinity and selectivity of such ligands toward different metal ions on the coordination chemistry front. On the signal transduction front, such effects can also be used to modulate optical responses of these ligands in metal sensing systems. In this review, steric modulation of achiral ligands and stereochemical modulation in chiral ligands, especially ionophores and sensors for zinc, copper, silver, and mercury, are examined using published structural and spectral data. Although it might be more challenging to construct chiral ligands than achiral ones, isotropic and anisotropic absorption signals from a single chiroptical fluorescent sensor provide not only detection but also differentiation of multiple analytes with high selectivity.

A peroxynitrite complex of copper: formation from a copper-nitrosyl complex, transformation to nitrite and exogenous phenol oxidative coupling or nitration.

Science.gov (United States)

Park, Ga Young; Deepalatha, Subramanian; Puiu, Simona C; Lee, Dong-Heon; Mondal, Biplab; Narducci Sarjeant, Amy A; del Rio, Diego; Pau, Monita Y M; Solomon, Edward I; Karlin, Kenneth D

2009-11-01

Reaction of nitrogen monoxide with a copper(I) complex possessing a tridentate alkylamine ligand gives a Cu(I)-(*NO) adduct, which when exposed to dioxygen generates a peroxynitrite (O=NOO(-))-Cu(II) species. This undergoes thermal transformation to produce a copper(II) nitrito (NO(2) (-)) complex and 0.5 mol equiv O(2). In the presence of a substituted phenol, the peroxynitrite complex effects oxidative coupling, whereas addition of chloride ion to dissociate the peroxynitrite moiety instead leads to phenol ortho nitration. Discussions include the structures (including electronic description) of the copper-nitrosyl and copper-peroxynitrite complexes and the formation of the latter, based on density functional theory calculations and accompanying spectroscopic data.

A Stable Coordination Complex of Rh(IV) in an N,O-Donor Environment

Energy Technology Data Exchange (ETDEWEB)

Sinha, Shashi B. [Department of Chemistry, Yale University, 225 Prospect; Shopov, Dimitar Y. [Department of Chemistry, Yale University, 225 Prospect; Sharninghausen, Liam S. [Department of Chemistry, Yale University, 225 Prospect; Vinyard, David J. [Department of Chemistry, Yale University, 225 Prospect; Mercado, Brandon Q. [Department of Chemistry, Yale University, 225 Prospect; Brudvig, Gary W. [Department of Chemistry, Yale University, 225 Prospect; Crabtree, Robert H. [Department of Chemistry, Yale University, 225 Prospect

2015-12-10

We describe facial and meridional isomers of [RhIII(pyalk)3], as well as meridional [RhIV(pyalk)3]+ {pyalk =2-(2-pyridyl)-2-propanoate}, the first coordination complex in an N,O-donor environment to show a clean, reversible RhIII/IV redox couple and to have a stable Rh(IV) form, which we characterize by EPR and UV–visible spectroscopy as well as X-ray crystallography. The unprecedented stability of the Rh(IV) species is ascribed to the exceptional donor strength of the ligands, their oxidation resistance, and the meridional coordination geometry.

Mutual passivation of group IV donors and isovalent nitrogen in diluted GaN{sub x}As{sub 1-x} alloys

Energy Technology Data Exchange (ETDEWEB)

Yu, K.M.; Wu, J.; Walukiewicz, W.; Shan, W.; Beeman, J.; Mars, D.E.; Chamberlin, D.R.; Scarpulla, M.A.; Dubon, O.D.; Ridgway, M.C.; Geisz, J.F.

2003-07-23

We demonstrate the mutual passivation of electrically active group IV donors and isovalent N atoms in the GaN{sub x}As{sub 1-x} alloy system. This phenomenon occurs through the formation of a donor-nitrogen bond in the nearest neighbor IV{sub Ga}-N{sub As} pairs. In Si doped GaInN{sub 0.017}As{sub 0.983} the electron concentration starts to decrease rapidly at an annealing temperature of 700 C from {approx} 3 x 10{sup 19}cm{sup -3} in the as-grown state to less than 10{sup 16}cm{sup -3} after an annealing at 900 C for 10 s. At the same time annealing of this sample at 950 C increases the gap by about 35 meV, corresponding to a reduction of the concentration of the active N atoms by an amount very close to the total Si concentration. We also show that the formation of Si{sub Ga}-N{sub As} pairs is controlled by the diffusion of Si via Ga vacancies to the nearest N{sub As} site. The general nature of this mutual passivation effect is confirmed by our study of Ge doped GaN{sub x}As{sub 1-x} layers formed by N and Ge co-implantation in GaAs followed by pulsed laser melting.

Synthesis characterization and biological evaluation of a novel mixed ligand 99mTc complex as potential brain imaging agent

International Nuclear Information System (INIS)

Rey, A.; Manta, E.; Leon, A.; Papadopoulos, M.; Pirmettis, Y.; Raptopoulou, C.; Chiotellis, E.; Leon, E.; Mallo, L.

1998-01-01

One approach in the design of neutral oxotechnetium complexes is based on the simultaneous substitution of a tridentate dianionic ligand and a monodentate monoanionic coligand on a [Tc(V)O] +3 precursor. Following this ''mixed ligand'' concept, a novel 99m Tc complex with N,N-bis(2-mercaptoethyl)-N'N'-diethylethylenediamine as ligand and 1-octanethiol as coligand is prepared and evaluated as potential brain radiopharmaceutical. Preparation of the complex at tracer level was accomplished by using 99m Tc-glucoheptonate as precursor. The substitution was optimized and a coligand/ligand ratio of 5 was selected. Under this conditions the labeling yield was over 80% and a major product (with radiochemical purity > 80%) was isolated by HPLC methods and used for biological evaluation. Chemical characterization at carrier level was developed using the corresponding rhenium complex as structural model. The Re complex was also prepared by substitution method and isolated as a crystalline product. The crystals were characterized by UV-vis and IR spectra and elemental analysis. Results were consistent with the expected ReOLC structure. X ray crystallographic study demonstrated that the complex adopts a distorted trigonal bipyramidal geometry. The basal plane is defined by the SS atoms of the ligand and the oxo group, while the N of the ligand and the S of the colligand occupy the two apical positions. All sulphur atoms underwent ionization leading to the formation of a neutral compound. 99 Tc complex was also prepared. Although it was not isolated due to the small amount of reagents employed, the HPLC profile was identical to the one observed for the rhenium complex suggesting the same chemical structure. Biodistribution in mice demonstrated early brain uptake, fast blood clearance, excretion through hepatobiliary system and a brain/blood ratio that increased significantly with time. (author)

Does the position of the electron-donating nitrogen atom in the ring system influence the efficiency of a dye-sensitized solar cell? A computational study.

Science.gov (United States)

Biswas, Abul Kalam; Barik, Sunirmal; Das, Amitava; Ganguly, Bishwajit

2016-06-01

We have reported a number of new metal-free organic dyes (2-6) that have cyclic asymmetric benzotripyrrole derivatives as donor groups with peripheral nitrogen atoms in the ring, fluorine and thiophene groups as π-spacers, and a cyanoacrylic acid acceptor group. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were employed to examine the influence of the position of the donor nitrogen atom and π-conjugation on solar cell performance. The calculated electron-injection driving force (ΔG inject), electron-regeneration driving force (ΔG regen), light-harvesting efficiency (LHE), dipole moment (μ normal), and number of electrons transferred (∆q) indicate that dyes 3, 4, and 6 have significantly higher efficiencies than reference dye 1, which exhibits high efficiency. We also extended our comparison to some other reported dyes, 7-9, which have a donor nitrogen atom in the middle of the ring system. The computed results suggest that dye 6 possesses a higher incident photon to current conversion efficiency (IPCE) than reported dyes 7-9. Thus, the use of donor groups with peripheral nitrogen atoms appears to lead to more efficient dyes than those in which the nitrogen atom is present in the middle of the donor ring system. Graphical Abstract The locations of the nitrogen atoms in the donor groups in the designed dye molecules have an important influence on DSSC efficiency.

Regio- and stereo-selective polymerization of 1,3-butadiene catalyzed by phosphorus–nitrogen PN3-pincer cobalt(ii) complexes

KAUST Repository

Gong, Dirong

2016-11-11

A new family of cobalt complexes (CoCl2-H, CoCl2-Me, CoCl2-iPr, CoBr2-H, CoBr2-Me, CoBr2-iPr, CoI2-H, CoI2-Me, and CoI2-iPr) supported by a PN3 ligand (6-(N,N′-di-t-butylphosphino)-2-pyrazol-yl-aminopyridine) have been prepared and fully characterized by FT-IR, elemental analysis, and X-ray analysis. The X-ray analysis reveals a trigonal bipyramidal conformation in the solid state for all representative complexes, CoCl2-H, CoBr2-H, CoBr2-iPr and CoI2-Me. The cobalt center is chelated by the PN3 ligand through the pyridinyl nitrogen, the pyrazol nitrogen and the phosphorus donor, with a long Co-P bond distance indicating a labile character. On activation with AlEt2Cl, Al2Et3Cl3, MAO, [Ph3C]+[B(C6F5)4]-/AliBu3 or AliBu3, cis-1,4 selective butadiene polymerization was achieved with up to 98.6% selectivity. The polymerization results show that the cis-1,4 selectivity is influenced by the steric hindrance, increasing with the bulkiness of the substituent groups (CoX2-iPr > CoX2-Me > CoX2-H) at the 3,5-positions of the pyrazole moiety, together with a slight decrease in activity. The activity changes in the order CoCl2L ≈ CoBr2L > CoI2L (for the same ligand L) when MAO is used as the activator, while the high level of cis-1,4 selectivity is maintained. It is possible to switch the selectivity from cis-1,4 to syndiotactic-1,2 by adding PPh3 © The Royal Society of Chemistry.

Conducting Polymers Functionalized with Phthalocyanine as Nitrogen Dioxide Sensors

Directory of Open Access Journals (Sweden)

S. D. Deshpande

2002-05-01

Full Text Available The conducting polymers such as polyaniline, polypyrrole and polythiophene were functionalized with copper phthalocyanine using chemical oxidation method. The obtained polymers viz. PANI-CuPc, PPy-CuPc and PT-CuPc were studied as chemical sensors by their response characteristics after exposure to various chemical vapors such as methanol, ammonia and nitrogen dioxide. The results obtained showed that these polymers have moderate sensitivity towards the methanol as well as ammonia vapors whereas they show tremendous sensitivity towards nitrogen dioxide vapors. The sensitivity factor of as high as 50,000 was obtained for PT-CuPc polymers in nitrogen dioxide. In comparison to this, the sensitivity factors of about 100 and 40 were obtained, when these polymers were exposed to ammonia and methanol vapors. The very high selectivity towards the nitrogen dioxide was explained on the basis of charge transfer complex formed between, the phthalocyanine donor and nitrogen dioxide acceptor molecules. On the other hand, ammonia becomes a competing electron donor in CuPc containing conducting polymers. The very low response towards the methanol may be explained on the basis very little charge transfer / interaction between CuPc containing polymers and methanol. Thus, CuPc incorporated conducting polymers have much higher selectivity than their original homopolymer.

Kinetics of a redox reaction in the system Ce(IV) β-diketonate - additional ligand

International Nuclear Information System (INIS)

Anufrieva, S.I.; Snezhko, N.I.; Pechurova, N.I.; Martynenko, L.N.; Spitsyn, V.I.

1982-01-01

Preparation of solutions containing stable compounds of Ce(IV) with organic ligands is difficult, because even strong Ce(IV) complexes undergo intramolecular reduction and have a tendency to hydrolysis. It is known that Ce(IV) β-diketonates have different resistances to reduction inorganic solvents, depending on the structure. Using spectrophotometric analysis we have investigated the oxidation-reduction characteristics of solutions of certain Ce(IV) β-diketonates in benzene in the absence and presence of neutral ligands containing donor O or N atoms

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

African Journals Online (AJOL)

A hydrazonic ligand, o-vanillin acetylhydrazone (H2L) has been prepared and used as chelating agent towards copper(II) ion. The ligand acts like a tridentate ligand in the monodeprotonated (HL-) and dideprotonated (L2-) states. Monoanionic complexes [{Cu(HL)(H2O)}2]•2BF4 and [{Cu(HL)(Hpz)(H2O)}]•NO3 have been ...

Some regularities of Ce(3) and Ce(4) stabilization in their compounds with β-diketones

International Nuclear Information System (INIS)

Pechurova, N.I.; Martynenko, L.I.; Snezhko, N.I.; Anufrieva, S.I.

1985-01-01

Adduct formation of cerium (3) and cerium (4) β-diketonates (acetylacetonate, benzoylacetonate, dibenzoylmethanate and thenoyltrifluoroacetonate) with oxygen- and nitrogen-donor ligands (Q-α, α'-dipyridyl, o-phenanthroline, trioctylphosphine oxide and triphenylphosphine oxide) is studied. The compounds obtained as a results of the reactions are studied by means of IR-spectroscopic, derivatographic and X-ray phase methods. It is concluded that composition and thermodynamic stability of adducts of Ce(3) tris-β-diketonates are determined by correlation of donor properties of the basis and additional ligand and stability of adducts to oxidation - as well as by their solubility. Introduction of the additional ligand to the system Ce(4)-β-diketones even in the presence of air oxygen stabilizes Ce(3) and destabilizes Ce(4)

(Acetonitrile[bis(2-pyridylmethylamine]bis(perchloratocopper(II

Directory of Open Access Journals (Sweden)

Ray J. Butcher

2008-01-01

Full Text Available In the title compound, [Cu(ClO42(C12H13N3(C2H3N], the CuII atom is six-coordinate in a Jahn–Teller distorted octahedral geometry, with coordination by the tridentate chelating ligand, an acetonitrile molecule, and two axial perchlorate anions. The tridentate ligand bis(2-pyridylmethylamine chelates meridionally and equatorially while an acetonitrile molecule is coordinated at the fourth equatorial site. The two perchlorate anions are disordered with site occupancy factors of 0.72/0.28. The amine H is involved in intramolecular hydrogen bonding to the perchlorate O atoms and there are extensive but weak intermolecular C—H...O interactions.

A feasibility study of unconventional planar ligand spacers in chalcogenide nanocrystals.

Science.gov (United States)

Lukose, Binit; Clancy, Paulette

2016-05-18

The solar cell efficiency of chalcogenide nanocrystals (quantum dots) has been limited in the past by the insulation between neighboring quantum dots caused by intervening, often long-chain, aliphatic ligands. We have conducted a computationally based feasibility study to investigate the use of ultra-thin, planar, charge-conducting ligands as an alternative to traditional long passive ligands. Not only might these radically unconventional ligands decrease the mean distance between adjacent quantum dots, but, since they are charge-conducting, they have the potential to actively enhance charge migration. Our ab initio studies compare the binding energies, electronic energy gaps, and absorption characteristics for both conventional and unconventional ligands, such as phthalocyanines, porphyrins and coronene. This comparison identified these unconventional ligands with the exception of titanyl phthalocyanine, that bind to themselves more strongly than to the surface of the quantum dot, which is likely to be less desirable for enhancing charge transport. The distribution of finite energy levels of the bound system is sensitive to the ligand's binding site and the levels correspond to delocalized states. We also observed a trap state localized on a single Pb atom when a sulfur-containing phenyldithiocarbamate (PTC) ligand is attached to a slightly off-stoichiometric dot in a manner that the sulfur of the ligand completes stoichiometry of the bound system. Hence, this is indicative of the source of trap state when thio-based ligands are bound to chalcogenide nanocrystals. We also predict that titanyl phthalocyanine in a mix with chalcogenide dots of diameter ∼1.5 Å can form a donor-acceptor system.

Synthesis and complexation of acyclic dithiolate ligands

International Nuclear Information System (INIS)

Ashford, L.

1999-11-01

Four approaches to ring substituted and unsubstituted N,N'-bis(o-mercaptobenzyliden)propylenediaminate ligands are described using N,N-dimethylcarbamate as a thiolate protecting group. Of the four basic methods, substitution, reduction, rearrangement and oxidation, the latter two successfully synthesise the aldehyde precursor. Rearrangement of the thiocarbamoyl group to the protected thiophenol is shown to be facilitated by a para-nitro substiuent. Ni(II) and Cu(II) complexes of N,N'-bis(p-nitro-o-mercaptobenzyliden)-propylenediaminate are synthesised by reaction of 2-formyl-4-nitro-N,N-dimethylcarbamoyI thiophenol, [Ni(OAc) 2 ].4(H 2 O) and 1,3-diaminopropane. The para-unsubstituted Ni(II) complex, Nickel-[N,N'-bis(o-mercaptobenzyliden) propylenediaminate] is prepared via reaction of the aldehyde, 2-formyl-N,N-dimethylcarbamoyl thiophenol with [Ni(OAc) 2 ].4(H 2 O) and 1,3-diaminopropane. The analogous carbamoyl-protected amine ligands, N,N'-dimethyl-N.N'-di[2-(N'',N''-dimethylcarbamyl)mercapto] benzyl-1,3-propane-diamine and N,N'-dimethyl-N,N'-di[2-(N'',N''-dimethylcarbamyl)mercapto] benzyl-1,2-ethane-diamine are also studied. The tertiary-butyl-protected diimine ligand, N,N'-bis-(o-mercaptobenzylidene)-propylenediaminate is prepared from 2-(tert-butylsulfanyl)benzaldehyde and 1,3-diaminopropane. Reaction with [Ni(H 2 O) 6 ]Cl 2 gives Nickel-[N,N'-bis(o-mercaptobenzyliden)-propylenediaminate], the crystal structure showing a distorted square-planar Ni(II) centre. Reaction with ZnCl 2 gives Zinc-[N,N'-bis(o-mercaptobenzyliden)propylenediaminate]dichloride. The crystal structure shows the thiolate donors remain protected and uncoordinated. The Zn(II) ion is coordinated by two imine donors and two chloride ions in a tetrahedral environment. In reactions with Ag(I) and Hg(II), N,N'-bis-(o-mercaptobenzylidene)-propylenediaminate acts as a reductant giving the free metals. Structural data and NMR and IR spectroscopic data for Nickel

Recruitment of feces donors among blood donors

DEFF Research Database (Denmark)

Dahl Jørgensen, Simon Mark; Erikstrup, Christian; Dinh, Khoa Manh

2018-01-01

As the use of fecal microbiota transplantation (FMT) has gained momentum, an increasing need for continuous access to healthy feces donors has developed. Blood donors constitute a healthy subset of the general population and may serve as an appropriate group for recruitment. In this study, we...... investigated the suitability of blood donors as feces donors. In a prospective cohort study, we recruited blood donors onsite at a public Danish blood bank. Following their consent, the blood donors underwent a stepwise screening process: First, blood donors completed an electronic pre-screening questionnaire...... to rule out predisposing risk factors. Second, eligible blood donors had blood and fecal samples examined. Of 155 blood donors asked to participate, 137 (88%) completed the electronic pre-screening questionnaire, 16 declined, and 2 were excluded. Of the 137 donors who completed the questionnaire, 79 (58...

Polymer complexes.. XXXX. Supramolecular assembly on coordination models of mixed-valence-ligand poly[1-acrylamido-2-(2-pyridyl)ethane] complexes

Science.gov (United States)

El-Sonbati, A. Z.; El-Bindary, A. A.; Diab, M. A.

2003-02-01

The build-up of polymer metallic supramolecules based on homopolymer (1-acrylamido-2-(2-pyridyl)ethane (AEPH)) and ruthenium, rhodium, palladium as well as platinum complexes has been pursued with great interest. The homopolymer shows three types of coordination behaviour. In the mixed valence paramagnetic trinuclear polymer complexes [( 11)+( 12)] in the paper and in mononuclear polymer complexes ( 1)-( 5) it acts as a neutral bidentate ligand coordinating through the N-pyridine and NH-imino atoms, while in the mixed ligand diamagnetic poly-chelates, which are obtained from the reaction of AEPH with PdX 2 and KPtCl 4 in the presence of N-heterocyclic base consisting of polymer complexes ( 9)+( 10), and in monouclear compounds ( 6)-( 8), it behaves as a monobasic bidentate ligand coordinating through the same donor atoms. In mononuclear compounds ( 13)+( 14) it acts as a monobasic and neutral bidentate ligand coordinating only through the same donor atoms. Monomeric distorted octahedral or trimeric chlorine-bridged, approximately octahedral structures are proposed for these polymer complexes. The poly-chelates are of 1:1, 1:2 and 3:2 (metal-homopolymer) stoichiometry and exhibit six coordination. The values of ligand field parameters were calculated. The homopolymer and their polymer complexes have been characterized physicochemically.

A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

International Nuclear Information System (INIS)

Wang, Jun; Bai, Chao; Hu, Huai-Ming; Yuan, Fei; Xue, Gang-Lin

2017-01-01

Eight Zn(II)-based coordination polymers, namely, [Zn 2 L 2 (2,2’-bipy)] n ·nH 2 O (1), [Zn 2 L 2 (phen)] n ·nH 2 O (2), [ZnL(phen)(H 2 O)] n (3), [Zn 3 L 3 (4,4’-bipy)] n (4), [Zn 2 L 2 (4,4’-bipy) 2 ] n [Zn 2 L 2 (H 2 O) 2 ] n ·2nH 2 O (5), [Zn 4 L 4 (bpp) 2 ] n (6), [ZnL(bbi) 0.5 ] n (7), [ZnL(bpz)] n (8) (H 2 L=4,4’-([1,2-phenylenebis-(methylene)]bis(oxy))dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu 2+ cations and CrO 4 2- anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials. - Graphical abstract: Eight new Zn(II)-based coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and different N-donor ligands have been hydrothermally synthesized through fixing the metal salts and the solvent systems. The photoluminescent properties of complexes 1−8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu 2+ cations and CrO 4 2- anions, as well as detection ability for the different organic solvents and nitro explosives, in which indicates it could be

A series of coordination polymers constructed from R-isophthalic acid (R=–SO{sub 3}H, –NO{sub 2}, and –OH) and N-donor ligands: Syntheses, structures and fluorescence properties

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yong-Hong, E-mail: zhou21921@sina.com [School of Chemistry and Material Science, Huaibei Normal University, Huaibei 235000 (China); Zhou, Xu-Wan; Zhou, Su-Rong [School of Chemistry and Material Science, Huaibei Normal University, Huaibei 235000 (China); Tian, Yu-Peng; Wu, Jie-Ying [Department of Chemistry and Chemical Technology, Anhui University, Hefei 230039 (China)

2017-01-15

Six novel Zn(II), Cd(II), and Cu(II) mixed-ligand coordination complexes, namely, [Zn{sub 2}Na(sip){sub 2}(bpp){sub 3}(Hbpp)(H{sub 2}O){sub 2}]·8H{sub 2}O (1), [Cd{sub 3}(sip){sub 2}(nbi){sub 6}(H{sub 2}O){sub 2}]·7H{sub 2}O (2), [Zn(sip)(nbi){sub 2}(H{sub 2}O)]·Hnbi·3H{sub 2}O (3), [Cd(hip)(nbi){sub 2}(H{sub 2}O)]·nbi·5H{sub 2}O (4), [Cd{sub 2}(nip){sub 2}(nbi){sub 2}(H{sub 2}O){sub 2}]·DMF (5), and [Cu(nip)(nbi)(H{sub 2}O){sub 2}]·H{sub 2}O (6) (H{sub 3}sip=5-sulfoisophthalic acid, H{sub 2}hip=5-hydroxylisophthalic acid, H{sub 2}nip=5-nitroisophthalic acid, bpp=1,3-bis(4-pyridyl)propane, and nbi=6-nitrobenzimidazole) have been synthesized hydrothermally by the self-assembly of R-isophthalic acid (R=–SO{sub 3}H, –NO{sub 2}, and –OH) and N-donor ligands. Single crystal X-ray analyses reveal that two Zn(II) ions and one Na(I) ion of complex 1 are linked through O atoms to generate a 1D linear chain. Then the 2D supramolecular architectures are constructed via intermolecular interactions. In complex 2, the Cd1 ions are connected by bridging carboxyl groups from sip{sup 3−} anions to form 1D double chain, which are further connected by Cd2 ions to afford 2D layer structure. The adjacent 2D layers are further linked via hydrogen-bonding interactions to give 3D supramolecular network. Compounds 3–5 show 1D chain structures, which are assembled into 2D or 3D supramolecular frameworks via weak interactions. In compound 6, the Cu(II) ions are bridged by the nip{sup 2−} ligands to form 48-membered ring, which is assembled into 1Dchain via the π-π stacking interaction. In addition, the thermal stabilities and fluorescence properties of these compounds have also been studied. - Graphical abstract: A series of Cd(II)/Zn(II)/ Cu(II) coordination polymers based on R-isophthalic acid (R=–SO{sub 3}H, –NO{sub 2}, and –OH) and N-donor ligands have been synthesized under hydrothermal conditions and structurally characterized. Photoluminescent properties

Study of substitution reactions of ligands in VO2+ complexes in toluene solutions by ESR method

International Nuclear Information System (INIS)

Lundkvist, R.; Panfilov, A.T.; Kalinichenko, N.B.; Marov, I.N.; AN SSSR, Moscow. Inst. Geokhimii i Analiticheskoj Khimii)

1976-01-01

Kinetics and equilibrium of stepwise substitution of ligands have been investigated at different temperatures for the complexes of oxovanadium (4) with salicylaldoxime, 8-oxyquinoline, acetylacetone, benzoylacetone, and tenoyltrifluoroacetone. The relative complexability of these ligands in toluene has been studied. The parameters of spin-Hamiltonian of EPR spectra of the VO 2+ complexes have been determined. The equilibrium constants, the rate constants, and activation energy have been found for the substitution reactions of ligands in the complexes VOA 2 : VOA 2 +HB=VOAB+HA; VOAB+HB=VOB 2 +HA, where HA and HB are the ligands with different donor atoms. The mixed complexes have been detected of the general formula VOAB, where HA is salicylaldoxime or 8-oxyquinoline and HB is β-diketone

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels.

Science.gov (United States)

Balotf, Sadegh; Islam, Shahidul; Kavoosi, Gholamreza; Kholdebarin, Bahman; Juhasz, Angela; Ma, Wujun

2018-01-01

Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.

Electrochemical and spectroscopic studies of tungstencarbonyl complexes containing nitrogen and phosphorous ligands

Directory of Open Access Journals (Sweden)

Haddad Paula S.

2000-01-01

Full Text Available The present work deals with the synthesis, spectroscopic investigation and electrochemical behaviour of the compounds [W(CO4(bipy] (1, [W(CO3(bipy(dppm] (2 and [W(CO3(bipy(dppf] (3, bipy = 2,2'-bipyridine; dppm = bis(diphenylphosphinomethane; dppf = 1,1'-bis(diphenylphosphinoferrocene. The IR and 31P{¹H} NMR spectroscopic data have shown an octahedral coordination geometry for the tungsten atom with the diphosphines acting as monodentate ligands. The electrochemical behaviour of the complexes was investigated by cyclic voltammetry and controlled potential coulometry. Cyclic voltammograms have indicated that the compounds containing diphosphines ligands are more stable towards oxidation than compound (1.

Synthesis and characterisation of some lanthanon-tris (chlorosulphate) complexes with nitrogen and oxygen donors

International Nuclear Information System (INIS)

Zaidi, S.A.A.; Zaidi, S.R.A.; Zahoor, M.A.; Khan, T.A.

1992-01-01

Some eight-coordinated complexes of Eu II , Tm II and Yb II chlorosulphates with pyridine, pyridine-N-oxide, acridine and bipyridine have been prepared and characterised by elemental analyses, conductance magnetic and infrared spectral data. Spectroscopic investigation has shown that SO 3 Cl - groups and bipyridyl ligand are all coordinated to the metal ions in a bidentate manner whereas the other ligand groups are coordinated monodentately. (author). 5 refs., 1 tab

Some mixed ligand hydridocarbonyl and hydridophosphine complexes of ruthenium(II) and iridium(III)

International Nuclear Information System (INIS)

Pandey, R.N.; Kumar, Sunil; Kumar, Arun; Kumar, S.K.

1993-01-01

Mixed-ligand hydridocarbonyl and hydridophosphine complexes of Ru II and Ir III have been isolated from the displacement reaction of [RuH(CO)(Pφ 3 ) 3 Cl] with ligand isonicotinic acid hydrazide (INAH) in benzene medium. Most probable structures are assigned on the basis of elemental analysis, electronic, infrared and far-infrared spectral studies. In all cases bonding of INAH occurs through amino nitrogen of hydrazine residue. (author). 15 refs., 1 tab

Synthesis and characterization of divalent metal complexes with ligand derived from the reaction of 3-aminopyridine and biacetyl

Directory of Open Access Journals (Sweden)

RAMESH KUMAR

2006-09-01

Full Text Available Divalent cobalt, nickel and copper salts reacted in situ with 3-aminopyridine and biacetyl to form complexes of the type: [M(Ap2biac2X2], where Ap2biac is the ligand and X=Cl, Br, NO3 or NCS. The complexes were analysed and characterized as distorted octahedral by conductance, molecular weight, magnetic, electronic and IR spectral studies. The electronic spectra were interpreted and tentative aassignments made. The infrared spectral studies revealed that two molecules of 3-aminopyridine were joined by molecules of biacetyl through a two carbon atom bridge and that the ligand coordinated through azomethine nitrogen atoms, whereas the pyridine nitrogen does not participate in the coordination. In the far infrared spectra, various metal–ligand vibrations were observed and are discussed.

Request for Information from entities interested in commercializing Laboratory-developed homogeneous catalyst technology

Energy Technology Data Exchange (ETDEWEB)

Intrator, Miranda Huang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-02-25

Many industrial catalysts used for homogeneous hydrogenation and dehydrogenation of unsaturated substrates are derived from metal complexes that include (air-sensitive) ligands that are often expensive and difficult to synthesize. In particular, catalysts used for many hydrogenations are based on phosphorus containing ligands (in particular PNP pincer systems). These ligands are often difficult to make, are costly, are constrained to having two carbon atoms in the ligand backbone and are susceptible to oxidation at phosphorus, making their use somewhat complicated. Los Alamos researchers have recently developed a new and novel set of ligands that are based on a NNS (ENENES) skeleton (i.e. no phosphorus donors, just nitrogen and sulfur).

The next chapter in MOF pillaring strategies: Trigonal heterofunctional ligands to access targeted high-connected three dimensional nets, isoreticular platforms

KAUST Repository

Eubank, Jarrod F.

2011-11-09

A new pillaring strategy, based on a ligand-to-axial approach that combines the two previous common techniques, axial-to-axial and ligand-to-ligand, and permits design, access, and construction of higher dimensional MOFs, is introduced and validated. Trigonal heterofunctional ligands, in this case isophthalic acid cores functionalized at the 5-position with N-donor (e.g., pyridyl- or triazolyl-type) moieties, are designed and utilized to pillar pretargeted two-dimensional layers (supermolecular building layers, SBLs). These SBLs, based on edge transitive Kagomé and square lattices, are cross-linked into predicted three-dimensional MOFs with tunable large cavities, resulting in isoreticular platforms. © 2011 American Chemical Society.

The next chapter in MOF pillaring strategies: Trigonal heterofunctional ligands to access targeted high-connected three dimensional nets, isoreticular platforms

KAUST Repository

Eubank, Jarrod F.; Wojtas, Łukasz; Hight, Matthew R.; Bousquet, Till; Kravtsov, Victor Ch H; Eddaoudi, Mohamed

2011-01-01

A new pillaring strategy, based on a ligand-to-axial approach that combines the two previous common techniques, axial-to-axial and ligand-to-ligand, and permits design, access, and construction of higher dimensional MOFs, is introduced and validated. Trigonal heterofunctional ligands, in this case isophthalic acid cores functionalized at the 5-position with N-donor (e.g., pyridyl- or triazolyl-type) moieties, are designed and utilized to pillar pretargeted two-dimensional layers (supermolecular building layers, SBLs). These SBLs, based on edge transitive Kagomé and square lattices, are cross-linked into predicted three-dimensional MOFs with tunable large cavities, resulting in isoreticular platforms. © 2011 American Chemical Society.

Frontiers in Gold Chemistry

OpenAIRE

Ahmed A. Mohamed

2015-01-01

Basic chemistry of gold tells us that it can bond to sulfur, phosphorous, nitrogen, and oxygen donor ligands. The Frontiers in Gold Chemistry Special Issue covers gold complexes bonded to the different donors and their fascinating applications. This issue covers both basic chemistry studies of gold complexes and their contemporary applications in medicine, materials chemistry, and optical sensors. There is a strong belief that aurophilicity plays a major role in the unending applications of g...

Spectroscopic characterization of metal complexes of novel Schiff base. Synthesis, thermal and biological activity studies

Science.gov (United States)

Omar, M. M.; Mohamed, Gehad G.; Ibrahim, Amr A.

2009-07-01

Novel Schiff base (HL) ligand is prepared via condensation of 4-aminoantipyrine and 2-aminobenzoic acid. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA, DrTGA and DTA). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a uninegatively tridentate manner with NNO donor sites of the azomethine N, amino N and deprotonated caroxylic-O. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ΔH*, ΔS* and ΔG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus Pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Shciff base ligand against one or more bacterial species.

Synthesis, electrochemistry, and spectroscopic properties of six-coordinate monooxomolybdenum(VI) complexes containing tridentate Schiff base and bidentate catecholate ligands. Crystal and molecular structure of (N-salicylidene-2-aminophenolato)(naphthalene-2,3-diolato)oxomolybdenum(VI)

International Nuclear Information System (INIS)

Mondal, J.U.; Schultz, F.A.; Brennan, T.D.; Scheidt, W.R.

1988-01-01

Six-coordinate monooxomolybdenum(VI) complexes, MoO(cat)(Sap), where Sap 2- = the Schiff base dianion N-salicylidene-2-aminophenolate and cat 2- = catecholate Cat 2- , naphthalene-2,3-diolate (Naphcat 2- ), or 3,5-di-tert-butylcatecholate (DTBcat 2- ), are prepared by reacting the Mo(VI) dimer. [MoO 2 (Sap)] 2 , with the appropriate catechol. The products are characterized by cyclic voltammetry, mass spectrometry, and uv/vis, ir, and 95 Mo NMR spectroscopy. The MoO(cat)(Sap) complexes represent the first examples of a mononuclear MoO 4+ center with a coordination number of six. The crystal structure of the MoO-(Naphcat)(Sap) derivative is reported, confirming the six-coordinate, distorted octahedrla environment about Mo(VI). Bond angles in the coordination group deviate from the ideal value of 90/degrees/ as a consequence of the ligand bite constraints and because all four O-Mo-O angles involving the terminal oxo ligand are larger than the ideal 90/degrees/ value. MoO(cat)(Sap) complexes undergo reversible one-electronic reduction at -0.5 to -0.7 V versus Fc /sup +/0/ followed by irreversible one-electron reduction at -1.6 to -1.9 V. Reversible MoO 4+ /MoO 3+ electrochemistry is attributed to the fact that the Mo d/sub xy/orbital of MoO(cat)(Sap) can be singly occupied upon reduction to Mo(V) without unfavorable interaction with the four bonds in its equatorial plane. This contrasts with the irreversible electrochemical behavior of seven-coordinate MoO 4+ complexes, which contain five such bonds. The 95 Mo NMR chemical shift of MoO(Naphcat)(Sap) is +385 ppM versus external molybdate; this value is highly deshielded with respect to seven-coordinate MoO 4+ and six-coordinate MoO 2 2+ complexes with O and N donors. 35 references, 4 figures, 5 tables

Prophage induction and mutagenicity of a series of anti-tumour platinum(II) and platinum(IV) co-ordination complexes

NARCIS (Netherlands)

Mattern, I.E.; Cocchiarella, L.; Kralingen, C.G. van; Lohman, P.H.M.

1982-01-01

Eleven platinum compounds with nitrogen donor ligands, previously tested for anti-tumour activity were studied for induction of prophage lambda and for mutagenicity in the Ames assay, with various strains of Salmonella. The compounds included cis and trans isomers of Pt(II) and Pt(IV) complexes and

Constructing two new crystalline metal–organic frameworks based on a mixed-donor ligand

KAUST Repository

Wang, Xiaofang; Xue, Ming; Wu, Gang; Pan, Ying; Qiu, Shilun

2016-01-01

© 2015 Elsevier B.V. All Rights Reserved. The self-assembly of a prominent ligand, 5-(4-(1H-tetrazolyl)phen)isophthalic acid (H3TZPI), with Zn2 +/Cu2 + centres generates two new MOFs, [Zn2(TZPI)(μ3-OH)(H2O)2]·2H2O (JUC-161) and [Cu(HTZPI)(μ2-H2O)0.5(H2O)1.5]·5(H2O) (JUC-162). JUC-161 exhibits fascinating three-dimensional structures containing rectangular channels with dimensions of 6.5 × 3.0 Å2, and JUC-162 displays 3D supramolecular structures with 12.5 × 14.6 Å2 hexagonal channels. The observed structural diversity in these frameworks is due to the two distinct coordinating moieties of the H3TZPI ligand. The photoluminescence of JUC-161 and the magnetic properties of JUC-162 are also measured at room temperature. Photoluminescence investigations reveal that JUC-161 displays a strong main emission spectrum peak at 388 nm. JUC-162 is found to exhibit an antiferromagnetic interaction between Cu2 + ions.

Constructing two new crystalline metal–organic frameworks based on a mixed-donor ligand

KAUST Repository

Wang, Xiaofang

2016-02-01

© 2015 Elsevier B.V. All Rights Reserved. The self-assembly of a prominent ligand, 5-(4-(1H-tetrazolyl)phen)isophthalic acid (H3TZPI), with Zn2 +/Cu2 + centres generates two new MOFs, [Zn2(TZPI)(μ3-OH)(H2O)2]·2H2O (JUC-161) and [Cu(HTZPI)(μ2-H2O)0.5(H2O)1.5]·5(H2O) (JUC-162). JUC-161 exhibits fascinating three-dimensional structures containing rectangular channels with dimensions of 6.5 × 3.0 Å2, and JUC-162 displays 3D supramolecular structures with 12.5 × 14.6 Å2 hexagonal channels. The observed structural diversity in these frameworks is due to the two distinct coordinating moieties of the H3TZPI ligand. The photoluminescence of JUC-161 and the magnetic properties of JUC-162 are also measured at room temperature. Photoluminescence investigations reveal that JUC-161 displays a strong main emission spectrum peak at 388 nm. JUC-162 is found to exhibit an antiferromagnetic interaction between Cu2 + ions.

Transition metal complexes with oxygen donor ligands: a synthesis, spectral, thermal and antimicrobial study

Directory of Open Access Journals (Sweden)

VAIBHAV N. PATANGE

2008-10-01

Full Text Available Transition metal complexes of chalcones derived from the conden¬sation of 3-acetyl-6-methyl-2H-pyran-2,4(3H-dione (dehydroacetic acid and p-methoxybenzaldehyde (HL1 or p-nitrobenzaldehyde (HL2 were synthesized and characterized by elemental analysis, conductometry, thermal analysis, magnetic measurements, IR, 1H-NMR, UV–Vis spectroscopy and a microbial study. From the analytical and thermal data, the stoichiometry of the complexes was found to be 1:2 (metal:ligand. The molar conductance data revealed that all the metal chelates were non-electrolytes. The thermal stability of the complexes was studied by thermogravimetry and the decomposition schemes of the complexes are given. The ligands and their metal complexes were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli, and fungicidal activity against Aspergillus flavus, Curvularia lunata and Penicillium notatum.

Ab Initio Ligand Field Molecular Mechanics and the Nature of Metal-Ligand π-Bonding in Fe(II) 2,6-di(pyrazol-1-yl)pyridine Spin Crossover Complexes.

Science.gov (United States)

Deeth, Robert J; Halcrow, Malcolm A; Kershaw Cook, Laurence J; Raithby, Paul R

2018-04-06

A ligand field molecular mechanics (LFMM) force field has been constructed for the spin states of [Fe(bpp) 2 ] 2+ (bpp=2,6-di(pyrazol-1-yl)pyridine) and related complexes. A new charge scheme is employed which interpolates between partial charges for neutral bpp and protonated [H 3 bpp] 3+ to achieve a target metal charge. The LFMM angular overlap model (AOM) parameters are fitted to fully ab initio d orbital energies. However, several AOM parameter sets are possible. The ambiguity is resolved by calculating the Jahn-Teller distortion mode for high spin, which indicates that in [Fe(bpp) 2 ] 2+ pyridine is a π-acceptor and pyrazole a weak π-donor. The alternative fit, assumed previously, where both ligands act as π-donors leads to an inconsistent distortion. LFMM optimisations in the presence of [BF 4 ] - or [PF 6 ] - anions are in good agreement with experiment and the model also correctly predicts the spin state energetics for 3-pyrazolyl substituents where the interactions are mainly steric. However, for 4-pyridyl or 4-pyrazolyl substituents, LFMM only treats the electrostatic contribution which, for the pyridyl substituents, generates a fair correlation with the spin crossover transition temperatures, T 1/2 , but in the reverse sense to the dominant electronic effect. Thus, LFMM generates its smallest spin state energy difference for the substituent with the highest T 1/2 . One parameter set for all substituted bpp ligands is insufficient and further LFMM development will be required. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Decay time shortening of fluorescence from donor-acceptor pair proteins using ultrafast time-resolved fluorescence resonance energy transfer spectroscopy

International Nuclear Information System (INIS)

Baba, Motoyoshi; Suzuki, Masayuki; Ganeev, Rashid A.; Kuroda, Hiroto; Ozaki, Tsuneyuki; Hamakubo, Takao; Masuda, Kazuyuki; Hayashi, Masahiro; Sakihama, Toshiko; Kodama, Tatsuhiko; Kozasa, Tohru

2007-01-01

We improved an ultrafast time-resolved fluorescence resonance energy transfer (FRET) spectroscopy system and measured directly the decrease in the fluorescence decay time of the FRET signal, without any entanglement of components in the picosecond time scale from the donor-acceptor protein pairs (such as cameleon protein for calcium ion indicator, and ligand-activated GRIN-Go proteins pair). The drastic decrease in lifetime of the donor protein fluorescence under the FRET condition (e.g. a 47.8% decrease for a GRIN-Go protein pair) proves the deformation dynamics between donor and acceptor fluorescent proteins in an activated state of a mixed donor-acceptor protein pair. This study is the first clear evidence of physical contact of the GRIN-Go proteins pair using time-resolved FRET system. G protein-coupled receptors (GPCRs) are the most important protein family for the recognition of many chemical substances at the cell surface. They are the targets of many drugs. Simultaneously, we were able to observe the time-resolved spectra of luminous proteins at the initial stage under the FRET condition, within 10 ns from excitation. This new FRET system allows us to trace the dynamics of the interaction between proteins at the ligand-induced activated state, molecular structure change and combination or dissociation. It will be a key technology for the development of protein chip technology

A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

Energy Technology Data Exchange (ETDEWEB)

Wang, Jun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); College of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, Zigong 643000 (China); Bai, Chao [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); Yuan, Fei; Xue, Gang-Lin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China)

2017-05-15

Eight Zn(II)-based coordination polymers, namely, [Zn{sub 2}L{sub 2}(2,2’-bipy)]{sub n}·nH{sub 2}O (1), [Zn{sub 2}L{sub 2}(phen)]{sub n}·nH{sub 2}O (2), [ZnL(phen)(H{sub 2}O)]{sub n} (3), [Zn{sub 3}L{sub 3}(4,4’-bipy)]{sub n} (4), [Zn{sub 2}L{sub 2}(4,4’-bipy){sub 2}]{sub n} [Zn{sub 2}L{sub 2}(H{sub 2}O){sub 2}]{sub n}·2nH{sub 2}O (5), [Zn{sub 4}L{sub 4}(bpp){sub 2}]{sub n} (6), [ZnL(bbi){sub 0.5}]{sub n} (7), [ZnL(bpz)]{sub n} (8) (H{sub 2}L=4,4’-([1,2-phenylenebis-(methylene)]bis(oxy))dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu{sup 2+} cations and CrO{sub 4}{sup 2-} anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials. - Graphical abstract: Eight new Zn(II)-based coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and different N-donor ligands have been hydrothermally synthesized through fixing the metal salts and the solvent systems. The photoluminescent properties of complexes 1−8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu{sup 2

Crystal structure of a mixed-ligand silver(I complex of the non-steroidal anti-inflammatory drug diclofenac and pyrimidine

Directory of Open Access Journals (Sweden)

Sevim Hamamci Alisir

2016-10-01

Full Text Available In the title mixed-ligand silver(I coordination polymeric complex with the non-steroidal anti-inflammatory drug diclofenac (C14H11Cl2NO2 (diclH and pyrimidine (pym, namely poly[{μ2-2-[2-(2,6-dichloroanilinophenyl]acetato-κ2O:O′}(μ2-pyrimidine-κ2N1:N3silver(I], [Ag(C14H10Cl2NO2(C4H4N2]n or [Ag(μ-dicl(μ-pym]n, the very distorted tetrahedral AgN2O2 coordination centres comprise two N-atom donors from bridging pym ligands [Ag—N = 2.381 (3 and 2.412 (3 Å] and two carboxylate O-atom donors from dicl ligands [Ag—O = 2.279 (2 and 2.280 (2 Å], which bridge Ag atoms, giving a centrosymmetric dinuclear units with a short Ag...Ag separation [2.8931 (5 Å]. Within the units are short intraligand C—Cl...π(pym interactions [3.6409 (15 Å]. The units are linked through the bridging N atoms of the pym ligand into a two-dimensional sheet–polymer structure lying parallel to (100 and stabilized by inter-ring π–π interactions between the pym ligands [Cg...Cg = 3.4199 (17 Å]. Additional inter-unit C—H...O and C—H...Cg hydrogen-bonding interactions between the sheets give an overall three-dimensional structure.

Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

Science.gov (United States)

Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

2015-01-01

A successive anchoring of Ti(NMe2)4, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1‧-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, 13C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands.

Synthesis of first row transition metal carboxylate complexes by ring ...

Indian Academy of Sciences (India)

tion of pyromellitic dianhydride with methanol and ring opening of pyromellitic dianhydride takes place. The corresponding carboxylate complex formed dur- ing the process can be crystallised by adding biden- tate nitrogen donor ligands such as 1,10-phenanthroline or 2,2 - bipyridine.20 From the reaction with 1,10-.

Tailored Band Gaps in Sulfur- and Nitrogen-Containing Porous Donor-Acceptor Polymers

Czech Academy of Sciences Publication Activity Database

Schwarz, D.; Kochergin, Y. S.; Acharjya, A.; Ichangi, Arun; Opanasenko, Maksym; Čejka, Jiří; Lappan, U.; Arki, P.; He, J.; Schmidt, J.; Nachtigall, P.; Thomas, A.; Tarábek, Ján; Bojdys, Michael J.

2017-01-01

Roč. 23, č. 53 (2017), s. 13023-13027 ISSN 0947-6539 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : conjugated microporous polymers * donor-acceptor dyads * photocatalysis * sulfur * triazine Subject RIV: CC - Organic Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) OBOR OECD: Organic chemistry; Physical chemistry (UFCH-W) Impact factor: 5.317, year: 2016

Highly stable [mambf6-n(o/h2o)n(ligand)2(solvent)x]n metal organic frameworks

KAUST Repository

Eddaoudi, Mohamed; Adil, Karim; Belmabkhout, Youssef; Shekhah, Osama; Bhatt, Prashant M.; Cadiau, Amandine

2016-01-01

Provided herein are metal organic frameworks having high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Metal organic frameworks can comprise metal nodes and N-donor organic ligands. Further provided

Hydroxyquinoline-calix[4]arene-conjugates as ligands for lanthanide complexes. Preparation, characterization, and extraction properties

Energy Technology Data Exchange (ETDEWEB)

Mansel, Alexander [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactive Transport; Jaeschke, A.; Kischel, M.; Kersting, B. [Leipzig Univ. (Germany). Inst. fuer Anorganische Chemie

2017-06-01

The synthesis of a calixarene-based N{sub 4}O{sub 4} donor ligand H{sub 6}L, in which two 8-hydroxyquinoline-2-carbaldehyde units are appended via hydrazone-carbonylmethoxy linkages in a 1,3-arrangement to the lower rim of tert-butyl-calix[4]arene and its coordination properties towards Eu{sup 3+} are described. Moreover, the ligand H{sub 6}L was found to extract Eu{sup 3+} and Tb{sup 3+} at pH 7-8 from aqueous solution, as established by radiotracing using the radionuclides {sup 160}Tb and {sup 152} Eu.

Synthesis, structural, antibacterial and spectral studies of Co (II) complexes with salicylaldehyde and p-chloro-benzaldehyde 4-phenyl thiosemicarbazone

International Nuclear Information System (INIS)

Nur Nadia Dzulkifli; Yang Farina; Ibrahim Baba; Nazlina Ibrahim

2012-01-01

The Co(II) complexes derived from salicylaldehyde 4-phenyl thiosemicarbazone; SaOHtsc, p-chlorobenzaldehyde 4-phenyl thiosemicarbazone; ph-HClbtsc is reported and characterized based on elemental analysis, IR, magnetic susceptibility measurement, 1 H and 13 C NMR spectra. The Co(II) complexes have the molecular formula CoL 2 where the ligand corresponding to SaOHtsc and ph-HClbtsc. The elemental analysis for the ligands and complexes were in a good agreement with the theoretical values. The ligands coordinate to metal ions in different ways which is through mono negative bidentate or di negative tridentate. The magnetic susceptibility measurements showed that the CoL 2 complexes with ligand SaOHtsc are diamagnetic thus making this complexes suitable for NMR studies. The signals at the 10.04 ppm were assigned to N 2 H in the 1 H-NMR spectra of the free ligands was absent in the spectra of the complexes due to the deprotonation of the N 2 H and coordination to the metal centres. The absence of the band in IR spectrum which is assigned to v(N 2 -H) in the spectra of CoL 2 complexes is due to the deprotonation of the ligands upon complexation through azomethine nitrogen and thionic sulphur atom to metal ion. The thiosemicarbazones and its Co(II) complexes showed moderate inhibitory against bacteria Bacillus Subtilis, Staphylococcus Epidermis, Escherichia Coli and Proteus Mirabilis in 10 μg/ disc. (author)

Roentgenographic and derivatographic investigation of gallium and indium complexes with azo compounds on the base of pyrogallol

International Nuclear Information System (INIS)

Gambarov, D.G.; Rzaev, R.Z.; Musaev, F.N.; Musaeva, A.N.; Chyragov, F.M.

1985-01-01

Seven complexes of gallium and indium with N-donor ligands obtained on the base of pyrogallol are synthesized. Their chemical composition is established. Nitrogen-containing ligands and their complexes are investigated by the methods of roentgenographic and thermogravimetric analyses. It is shown that gallium and indium complexes are amorphous compounds. An assumption is made on the thermolysis character that complexes have a similar structure: structural complex nucleus constitutes a six-term chelate ring. Para-substitutors in the ligand do not participate in complexing, possibly they participate in H-bonds formation. It is established by spectrophotometric methods that in solutions stoichiometric ratio metal: ligand is the same as in the solid phase

Roentgenographic and derivatographic investigation of gallium and indium complexes with azo compounds on the base of pyrogallol

Energy Technology Data Exchange (ETDEWEB)

Gambarov, D G; Rzaev, R Z; Musaev, F N; Musaeva, A N; Chyragov, F M

1985-01-01

Seven complexes of gallium and indium with N-donor ligands obtained on the base of pyrogallol are synthesized. Their chemical composition is established. Nitrogen-containing ligands and their complexes are investigated by the methods of roentgenographic and thermogravimetric analyses. It is shown that gallium and indium complexes are amorphous compounds. An assumption is made on the thermolysis character that complexes have a similar structure: structural complex nucleus constitutes a six-term chelate ring. Para-substitutors in the ligand do not participate in complexing, possibly they participate in H-bonds formation. It is established by spectrophotometric methods that in solutions stoichiometric ratio metal: ligand is the same as in the solid phase.

Heteroleptic complexes of Zn(II) based on 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide: Synthesis, structural characterization, theoretical studies and antibacterial activity

Science.gov (United States)

Azarkish, Mohammad; Akbari, Alireza; Sedaghat, Tahereh; Simpson, Jim

2017-04-01

Four new ternary complexes, [ZnL (2,2‧-bipy)] (1), Zn2L2(4,4‧-bipy)] (2), [ZnL(Imd)]·H2O (3) and [ZnL3(MeImd)] (4), have been synthesized from the reaction of Zn(II) acetate with 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide (H2L) in the presence of a heterocyclic base, 2,2‧-bipyridine, 4,4‧-bipyridine, imidazole or 2-methylimidazole, as an auxiliary ligand. The complexes have been investigated by elemental analysis and FT-IR, UV-Vis and 1HNMR spectroscopy. These data show that the thiosemicarbazone acts as a tridentate dianionic ligand and coordinates via the thiol group, imine nitrogen, and phenolic oxygen. The coordination sphere was completed by the nitrogen atom(s) of the secondary ligand. The structure of 1 was also confirmed by X-ray crystallography and shown to be a five coordinate complex with coordination geometry between the square-pyramidal and trigonal-bipyramidal. Density functional theory (DFT) calculations including geometry optimization, vibrational frequencies and electronic absorptions have been performed for 1 with the B3LYP functional at the TZP(6-311G*) basis set using the Gaussian 03 or ADF 2009 packages. The optimization calculation showed that the crystallographically determined geometry parameters can be reproduced with that basis set. Experimental IR frequencies and calculated vibration frequencies also support each other. The in vitro antibacterial activities of the ligand and complexes have been evaluated against Gram-positive (B. subtilis and S. aureus) and Gram-negative (P. aeruginosa) bacteria and compared with the standard antibacterial drugs. The results reveal that all of the complexes show much better activity in comparison to the individual thiosemoicarbazone ligand (H2L), against all bacterial strains used, with complex 3 showing the most promising results.

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphos Ph Complexes.

Science.gov (United States)

Phanopoulos, Andreas; Long, Nicholas; Miller, Philip

2015-04-10

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphos(Ph)) (1) via a phosphorus based Mannich reaction of the hydroxylmethylene phosphine precursor with ammonia in methanol under a nitrogen atmosphere. The N-triphos(Ph) ligand precipitates from the solution after approximately 1 hr of reflux and can be isolated analytically pure via simple cannula filtration procedure under nitrogen. Reaction of the N-triphos(Ph) ligand with [Ru3(CO)12] under reflux affords a deep red solution that show evolution of CO gas on ligand complexation. Orange crystals of the complex [Ru(CO)2{N(CH2PPh2)3}-κ(3)P] (2) were isolated on cooling to RT. The (31)P{(1)H} NMR spectrum showed a characteristic single peak at lower frequency compared to the free ligand. Reaction of a toluene solution of complex 2 with oxygen resulted in the instantaneous precipitation of the carbonate complex [Ru(CO3)(CO){N(CH2PPh2)3}-κ(3)P] (3) as an air stable orange solid. Subsequent hydrogenation of 3 under 15 bar of hydrogen in a high-pressure reactor gave the dihydride complex [RuH2(CO){N(CH2PPh2)3}-κ(3)P] (4), which was fully characterized by X-ray crystallography and NMR spectroscopy. Complexes 3 and 4 are potentially useful catalyst precursors for a range of hydrogenation reactions, including biomass-derived products such as levulinic acid (LA). Complex 4 was found to cleanly react with LA in the presence of the proton source additive NH4PF6 to give [Ru(CO){N(CH2PPh2)3}-κ(3)P{CH3CO(CH2)2CO2H}-κ(2)O](PF6) (6).

A multipurpose TIM-based optical telescope for Omega and the Trident laser facilities

International Nuclear Information System (INIS)

Oertel, J.A.; Murphy, T.J.; Berggren, R.R.

1998-01-01

The authors have recently designed and are building a telescope which acts as an imaging light collector relaying the image to an optical table for experiment dependent analysis and recording. The expected primary use of this instrument is a streaked optical pyrometer for witness plate measurements of Hohlraum drive temperature. The telescope is based on University of Rochester's Ten-Inch Manipulator (TIM) which allows compatibility between Omega, Trident, and the NIF lasers. The optics capture a f/7 cone of light, have a field of view of 6-mm, have a spatial resolution of 5 to 7-microm per line pair at the object plane, and are optimized for operation at 280-nm. The image is at a magnification of 11.7x, which is convenient for many experiments, but can be changed using additional optics that reside outside the TIM

A symmetry-controlled and face-driven approach for the assembly of cerium-based molecular polyhedra.

Science.gov (United States)

Liu, Yang; Lin, Zhihua; He, Cheng; Zhao, Liang; Duan, Chunying

2010-12-14

A well-defined Ce-based molecular tetrahedron and a cube-like architecture were achieved via self-assembly by incorporating NOO tridentate chelators into the rationally designed ligands with C(3) or C(2v) symmetries, respectively.

Beta-Phosphinoethylboranes as Ambiphilic Ligands in Nickel-Methyl Complexes

Energy Technology Data Exchange (ETDEWEB)

Fischbach, Andreas; Bazinet, Patrick R.; Waterman, Rory; Tilley, T. Don

2007-10-28

The ambiphilic {beta}-phosphinoethylboranes Ph{sub 2}PCH{sub 2}CH{sub 2}BR{sub 2} (BR{sub 2} = BCy{sub 2} (1a), BBN (1b)), which feature a ethano spacer CH{sub 2}CH{sub 2} between the Lewis acidic boryl and Lewis basic phosphino groups, were synthesized in nearly quantitative yields via the hydroboration of vinyldiphenylphosphine. Compounds 1a and 1b were fully characterized by elemental analysis, and by NMR and IR spectroscopy. X-ray crystallographic studies of compound 1b revealed infinite helical chains of the molecules connected through P{hor_ellipsis}B donor-acceptor interactions. The ability of these ambiphilic ligands to concurrently act as donors and acceptors was highlighted by their reactions with (dmpe)NiMe{sub 2}. Zwitterionic complexes (dmpe)NiMe(Ph{sub 2}PCH{sub 2}CH{sub 2}BCy{sub 2}Me) (2a) and (dmpe)NiMe(Ph{sub 2}PCH{sub 2}CH{sub 2}[BBN]Me) (2b) were generated via the abstraction of one of the methyl groups, forming a borate, and intramolecular coordination of the phosphine moiety to the resulting cationic metal center. Compound 2b was characterized by X-ray crystallography. Furthermore, B(C{sub 6}F{sub 5}){sub 3} abstracts the methyl group of a coordinated borate ligand to generate a free, 3-coordinate borane center in [(dmpe)NiMe(1a)]{sup +}[MeB(C{sub 6}F{sub 5}){sub 3}]{sup -} (3).

Donor Outcomes in Living Donor Liver Transplantation-Analysis of 275 Donors From a Single Centre in India.

Science.gov (United States)

Narasimhan, Gomathy; Safwan, Mohamed; Kota, Venugopal; Reddy, Mettu S; Bharathan, Anand; Dabora, Abderrhaim; Kaliamoorthy, Ilankumaran; Kanagavelu, Rathnavel G; Srinivasan, Vijaya; Rela, Mohamed

2016-06-01

Live donor liver transplantation is the predominant form of liver transplantation in India and in most Asian countries. Donor outcome reports are an important source of information to be shared with prospective donors at the time of informed consent. This is the first donor outcome series from India. Analysis of donor characteristics and morbidity of 275 live donors from a single large volume center is documented. Two hundred seventy-five patients donated from November 2009 to October 2014, 144 were women and 131 were men, 180 donated to adults and 95 donated to children. Right lobe donors were majority at 62.2% followed by left lateral segment 28%. Two thirds of the live donors did not have any morbidity; 114 complications were encountered in 85 patients. The complications were graded as per Clavien 5 tier grading and major morbidity (grade III b, grade IV grade V) was 4.36%. Postoperative biliary complication was seen in 3 donors. This large single-center study is the first donor outcome report from India, and the results are comparable to other published donor series. Documentation and regular audit of donor outcomes is important to help improve the safety of donor hepatectomy and to provide a database for informed consent of prospective donors.

Electrical activation of nitrogen heavily implanted 3C-SiC(1 0 0)

Energy Technology Data Exchange (ETDEWEB)

Li, Fan, E-mail: f.li.1@warwick.ac.uk [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Sharma, Yogesh; Shah, Vishal; Jennings, Mike [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Pérez-Tomás, Amador [ICN2 – Institut Catala de Nanociència i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain); Myronov, Maksym [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Fisher, Craig [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Leadley, David [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Mawby, Phil [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

2015-10-30

Highlights: • Nitrogen is fully activated by 1175 °C annealing for 1.5 × 10{sup 19} cm{sup −3} doped 3C-SiC. • Free donor concentration is found to readily saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. • 3C-SiC is found to have complete donor thermal ionization above 150 K. • Donor in 1.5 × 10{sup 19} cm{sup −3} nitrogen implanted 3C-SiC has an energy level ∼15 meV. • The SiO{sub 2} cap is found to have a bigger influence on low and medium doped samples. - Abstract: A degenerated wide bandgap semiconductor is a rare system. In general, implant levels lie deeper in the band-gap and carrier freeze-out usually takes place at room temperature. Nevertheless, we have observed that heavily doped n-type degenerated 3C-SiC films are achieved by nitrogen implantation level of ∼6 × 10{sup 20} cm{sup −3} at 20 K. According to temperature dependent Hall measurements, nitrogen activation rates decrease with the doping level from almost 100% (1.5 × 10{sup 19} cm{sup −3}, donor level 15 meV) to ∼12% for 6 × 10{sup 20} cm{sup −3}. Free donors are found to saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. The implanted film electrical performances are characterized as a function of the dopant doses and post implantation annealing (PIA) conditions by fabricating Van der Pauw structures. A deposited SiO{sub 2} layer was used as the surface capping layer during the PIA process to study its effect on the resultant film properties. From the device design point of view, the lowest sheet resistivity (∼1.4 mΩ cm) has been observed for medium doped (4 × 10{sup 19} cm{sup −3}) sample with PIA 1375 °C 2 h without a SiO{sub 2} cap.

Anammox revisited: thermodynamic considerations in early studies of the microbial nitrogen cycle.

Science.gov (United States)

Oren, Aharon

2015-08-01

This paper explores the early literature on the thermodynamics of processes in the microbial nitrogen cycle, evaluating parameters of transfer of energy which depends on the initial and final states of the system, the mechanism of the reactions involved and the rates of these reactions. Processes discussed include the anaerobic oxidation of ammonium (the anammox reaction), the use of inorganic nitrogen compounds as electron donors for anoxygenic photosynthesis, and the mechanism and bioenergetics of biological nitrogen fixation. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A series of coordination polymers constructed from R-isophthalic acid (R=-SO3H, -NO2, and -OH) and N-donor ligands: Syntheses, structures and fluorescence properties

Science.gov (United States)

Zhou, Yong-Hong; Zhou, Xu-Wan; Zhou, Su-Rong; Tian, Yu-Peng; Wu, Jie-Ying

2017-01-01

Six novel Zn(II), Cd(II), and Cu(II) mixed-ligand coordination complexes, namely, [Zn2Na(sip)2(bpp)3(Hbpp)(H2O)2]·8H2O (1), [Cd3(sip)2(nbi)6(H2O)2]·7H2O (2), [Zn(sip)(nbi)2(H2O)]·Hnbi·3H2O (3), [Cd(hip)(nbi)2(H2O)]·nbi·5H2O (4), [Cd2(nip)2(nbi)2(H2O)2]·DMF (5), and [Cu(nip)(nbi)(H2O)2]·H2O (6) (H3sip=5-sulfoisophthalic acid, H2hip=5-hydroxylisophthalic acid, H2nip=5-nitroisophthalic acid, bpp=1,3-bis(4-pyridyl)propane, and nbi=6-nitrobenzimidazole) have been synthesized hydrothermally by the self-assembly of R-isophthalic acid (R=-SO3H, -NO2, and -OH) and N-donor ligands. Single crystal X-ray analyses reveal that two Zn(II) ions and one Na(I) ion of complex 1 are linked through O atoms to generate a 1D linear chain. Then the 2D supramolecular architectures are constructed via intermolecular interactions. In complex 2, the Cd1 ions are connected by bridging carboxyl groups from sip3- anions to form 1D double chain, which are further connected by Cd2 ions to afford 2D layer structure. The adjacent 2D layers are further linked via hydrogen-bonding interactions to give 3D supramolecular network. Compounds 3-5 show 1D chain structures, which are assembled into 2D or 3D supramolecular frameworks via weak interactions. In compound 6, the Cu(II) ions are bridged by the nip2- ligands to form 48-membered ring, which is assembled into 1Dchain via the π-π stacking interaction. In addition, the thermal stabilities and fluorescence properties of these compounds have also been studied.

Palladium complexes with simple iminopyridines as catalysts for polyketone synthesis.

Science.gov (United States)

Rosar, V; Dedeic, D; Nobile, T; Fini, F; Balducci, G; Alessio, E; Carfagna, C; Milani, B

2016-10-07

Four iminopyridines (N-N') differing in the nature of the substituents on the iminic carbon and on the ortho positions of the aryl ring (H or CH3) on the iminic nitrogen were used for the synthesis of neutral and monocationic palladium(ii) complexes of general formulae [Pd(CH3)Cl(N-N')] and [Pd(CH3)(NCCH3)(N-N')][PF6]. The detailed NMR characterization in solution highlighted that: (i) for both series of complexes, the Pd-CH3 signal is progressively shifted to a lower frequency on increasing the number of methyl groups on the ligand skeleton; (ii) for the neutral derivatives, the chemical shift of the (15)N NMR signals, determined through {(1)H,(15)N}-HMBC spectra, is significantly affected by the coordination to palladium; (iii) the coordination induced shift (CIS) of the nitrogen atom trans to the CH3 ligand is smaller than the other. The structure in the solid state for the neutral derivatives with all the four ligands was solved, pointing out that: (iv) the Pd-C bond distance increases with the basicity of the nitrogen-donor ligand; (v) the Pd-N bond distance correlates well with the CIS value. The combining of the solution and solid state structural features allows stating that: (vi) the Pd-CH3 singlet is a good probe for the electron donor capability of the ligand; (vii) the CIS value might be used as a probe for the strength of the Pd-N bond. All monocationic complexes generated active catalysts for the CO/vinyl arene copolymerization, leading to prevailingly syndiotactic polyketones. The catalyst performances, both in terms of catalyst productivity and polymer molecular weight, correlate well with the precatalyst structural features.

Coordination behavior of bis-phenolate saturated and unsaturated N-heterocyclic carbene ligands to zirconium: reactivity and activity in the copolymerization of cyclohexene oxide with CO2.

Science.gov (United States)

Lalrempuia, Ralte; Breivik, Frida; Törnroos, Karl W; Le Roux, Erwan

2017-06-27

Tetravalent zirconium complexes supported by tridentate bis-phenolate imidazolidin-2-ylidene (L1), imidazol-2-ylidene (L2) and benzimidazol-2-ylidene (L3) NHC ligands were synthesized and evaluated as precursors for the copolymerization of cyclohexene oxide (CHO) with CO 2 . While the reactivity of the imidazolidinium [H 3 L1] chloride salt with Zr(OiPr) 4 (HOiPr), and subsequent ligand exchanges with either (CH 3 ) 3 SiCl or LiOiPr lead to a series of heteroleptic compounds (κ 3 -O,C,O-L1)Zr(X) 2 (THF) (X = Cl, OiPr), both imidazolium [H 3 L2] and benzimidazolium [H 3 L3] chloride salts give a mixture of homoleptic (κ 3 -O,C,O-NHC) 2 Zr and zwitterionic (κ 2 -O,O-HL)ZrCl 2 (OiPr) compounds along with traces or the absence of the heteroleptic intermediate (κ 3 -O,C,O-NHC)Zr(Cl)(OiPr)(THF). Such dissimilar reactivity between the unsaturated and saturated NHC ligands is predominantly ascribed to the increased acidity of azolium salts along with the π-donor strength of the C carbene in L2 and L3-Zr moieties. The reactivity with the more acidic azolium salts (H 3 L2/3) and the destabilized Zr-X trans to NHC carbene bond results in a significant increase in the amount of homoleptic compounds generating HCl. The released HCl reacts preferentially with the heteroleptic intermediates having non-planar NHC ligands (i.e. L2/3) promoting the formation of zwitterionic complexes. The in situ deprotonation of the isolated zwitterionic (κ 2 -O,O-HL3)ZrCl 2 (OiPr) compound by using Ag 2 O gives the homoleptic complex as the major component along with a bimetallic hydroxo-bridged [(κ 3 -O,C,O-L3)Zr(μ-OH)(OiPr)] 2 compound. Of particular interest is that only the heteroleptic NHC-Zr(iv) complexes were identified to be active and highly selective towards the copolymerization of CHO with CO 2 independently of the co-catalysts used (both anionic and neutral) under mild conditions (P CO 2 < 1 bar, T = 60 °C), and gave atactic and completely alternating copolymers in a

Highly stable [mambf6-n(o/h2o)n(ligand)2(solvent)x]n metal organic frameworks

KAUST Repository

Eddaoudi, Mohamed

2016-10-13

Provided herein are metal organic frameworks having high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Metal organic frameworks can comprise metal nodes and N-donor organic ligands. Further provided are methods of making metal organic frameworks.

Synthesis and characterization of 6,6'-bis(2-hydroxyphenyl)-2,2'-bipyridine ligand and its interaction with ct-DNA

Science.gov (United States)

Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd

2015-09-01

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6'-dibromo-2,2'-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6'-bis(2-methoxyphenyl)-2,2'-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by 1H, 2D cosy and 13C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant Kb = 1.19 × 103 ± 0.08 M-1.

Synthesis of a new technetium radiotracer containing ortho-toluidine by tridentate chelation in (N, N, O)

International Nuclear Information System (INIS)

Hosni, Zied

2011-01-01

The radiological diagnosis of brain diseases, including neuro degenerative ones, is still difficult because of the absence of specific biological markers. Theses diseases are then increasingly the subject of researches and new experiments. The aim of this investigation is the synthesis of a novel radiotracer able to overcome the blood brain barrier and to be selective to one of the cerebral receptors. Clinically, he employed method was convenient because of the use of complex tridentate in (N,N,O) that does nor require a preparation in high temperature. Whereas, in spite of its low molecular mass and its electric neutrality, the measured lipophilicity of the complex was not coherent with the values tolerated by this phisilogical membrane.

Catalytic behaviors of Co{sup II} and Mn{sup II} compounds bearing α-Diimine ligands for oxidative polymerization or drying oils

Energy Technology Data Exchange (ETDEWEB)

Lima, Gilvan E.S.; Nunes, Everton V.; Dantas, Roberta C.; Meneghetti, Mario R.; Meneghetti, Simoni M.P., E-mail: simoni.plentz@gmail.com [Universidade Federal de Alagoas (UFAL), Maceió, AL (Brazil). Grupo de Catálise e Reatividade Química; Simone, Carlos A. de [Universidade de Sao Paulo (USP), São Carlos, USP, SP (Brazil). Instituto de Física

2018-05-01

The oxidative polymerization of linseed oil was investigated comparing the classical catalysts cobalt(II) 2-ethylhexanoate and manganese(II) 2-ethylhexanoate and their derivatives modified by the presence of chelating nitrogen ligands, i.e., 2,2’-bipyridyl, 2-(acetyl-2,6-diisopropylphenylimine)- pyridine and [N-(2,6-diisopropylphenyl)imine]acenaphthoquinone. The suitable stoichiometries between the two precursor complexes with the three ligands were determined by UV-visible spectroscopy. All complexes were characterized by infrared spectroscopy, and one complex was characterized also by X-ray diffraction. The apparent kinetic constants of oxidative polymerization of linseed oil was determined, for each catalytic system, via the periodic measurements of the oil viscosity during the oxidation reaction. The results indicated that the modifications of the classical two complexes with the chelating nitrogen ligands improved the catalytic efficiency at least to the manganese complex. (author)

Binuclear and tetranuclear Mn(II) clusters in coordination polymers derived from semirigid tetracarboxylate and N‑donor ligands: syntheses, new topology structures and magnetism

Energy Technology Data Exchange (ETDEWEB)

Li, Xiao-Ling [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); Liu, Guang-Zhen, E-mail: gzliuly@126.com [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); Xin, Ling-Yun [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); Wang, Li-Ya [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang, Henan 473061 (China)

2017-02-15

Two topologically new Mn(II) coordination polymers, namely ([Mn{sub 2}(H{sub 4}ipca)(4,4′-bpy){sub 1.5}(CH{sub 3}CH{sub 2}OH){sub 0.5}(H{sub 2}O){sub 1.5}]·0.5CH{sub 3}CH{sub 2}OH·2.5H{sub 2}O){sub n} (1) and (Mn{sub 4}(H{sub 4}ipca){sub 2}(bze)(H{sub 2}O){sub 4}){sub n} (2) were prepared by the solvothermal reactions of Mn(II) acetate with 5-(2’,3’-dicarboxylphenoxy)isophthalic acid (H{sub 4}ipca) in the presence of different N-donor coligands (4,4′-bpy=4,4′-bipyridyl and bze=1, 4-bis(1-imidazoly)benzene). The single crystal X-ray diffractions reveal that two complexes display 3D metal-organic frameworks with binuclear and tetranuclear Mn(II) units, respectively. Complex 1 features a (3,4,6)-connected porous framework based on dinuclear Mn(II) unit with the (4.5{sup 2}){sub 2}(4{sup 2}.6{sup 8}.8{sup 3}.9{sup 2})(5{sup 2}.8.9{sup 2}.10) new topology, and complex 2 possesses a (3,8)-connected network based on tetranuclear Mn(II) unit with the (4{sup 2}.6){sub 2}(4{sup 4}.6{sup 14}.7{sup 7}.8{sup 2}.9) new topology. Magnetic analyses indicate that both two compounds show weak antiferromagnetic interactions within binuclear and tetranuclear Mn(II) units. - Graphical abstract: Two topologically new Mn(II) metal-organic frameworks with dinuclear and tetranuclear Mn(II) units respectively were assembled by using 5-(2′,3′-Dicarboxylphenoxy)isophthalic acid and N-donor ancillary coligands. Magnetic analysis revealed the existence of dominant antiferromagnetic interactions within the polynuclear Mn(II) units. - Highlights: • Mixed ligand strategy produces two topologically new MOFs with dinuclear and tetranuclear Mn(II) respectively. • Magnetic fitting gives weak antiferromagnetic interactions within the polynuclear Mn(II) units.

Relative stability constants of the uranyl tropolonate system with neutral ligands in benzene

Energy Technology Data Exchange (ETDEWEB)

Degetto, S; Baracco, L; Marangoni, G [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Celon, E

1976-01-01

The relative formation constants K*sub(L) of some uranyl tropolonate adducts with neutral ligands L (L = cyclopentanone, pyridine, dimethyl sulphoxide, 4-chloropyridine N-oxide, 4-methylpyridine N-oxide, triphenylphosphine oxide, and triphenylarsine oxide) of general formula (U0/sub 2/(trop)/sub 2/L) (Htrop = tropolone) have been determined spectrophotometrically by studying the equilibria ((UO/sub 2/(trop)/sub 2/)/sub 2/) + 2L = 2 (UO/sub 2/(trop)/sub 2/L) in the benzene at 25/sup 0/C. The K*sub(L) sequence obtained can be used as a quantitative scale of donor ability of the various neutral ligands toward the common substrate. Other attempted qualitative correlations based on i.r., /sup 1/H n.m.r., and thermal measurements are compared and discussed.

Mononuclear non-heme iron(III)

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 123; Issue 2. Mononuclear non-heme iron(III) complexes of linear and tripodal tridentate ligands as functional models for catechol dioxygenases: Effect of -alkyl substitution on regioselectivity and reaction rate. Mallayan Palaniandavar Kusalendiran Visvaganesan.

Synthesis, spectral, antitumor, antioxidant and antimicrobial studies on Cu(II), Ni(II) and Co(II) complexes of 4-[(1H-Benzoimidazol-2-ylimino)-methyl]-benzene-1,3-diol.

Science.gov (United States)

El-wakiel, Nadia; El-keiy, Mai; Gaber, Mohamed

2015-08-05

A new Schiff base of 2-aminobenzimidazole with 2,4-dihydroybezaldehyde (H₃L), and its Cu(II), Ni(II) and Co(II) complexes have been synthesized and characterized by elemental analyses, molar conductance, thermal analysis (TGA), inductive coupled plasma (ICP), magnetic moment measurements, IR, EI-mass, UV-Vis. and ESR spectral studies. On the basis of spectral studies and analytical data, it is evident that the Schiff base acts as dibasic tridentate ligand coordinating via deprotonated OH, NH and azomethine nitrogen atom. The results showed that Co(II) and Ni(II) complexes have tetrahedral structure while Cu(II) complexes has octahedral geometry. The kinetic and thermodynamic parameters of the thermal decomposition stages have been evaluated. The studied complexes were tested for their in vitro antimicrobial activities against some bacterial strains. The anticancer activity of the ligand and its metal complexes is evaluated against human liver Carcinoma (HEPG2) cell. These compounds exhibited a moderate and weak activity against the tested HEPG2 cell lines with IC₅₀ of 9.08, 18.2 and 19.7 μg/ml for ligand, Cu(II) and Ni(II) complexes, respectively. In vitro antioxidant activity of the newly synthesized compounds has also been evaluated. Copyright © 2015 Elsevier B.V. All rights reserved.

Synergistic complexes of uranyl ion with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 and some oxo-donors

International Nuclear Information System (INIS)

Nagar, M.S.; Ruikar, P.B.; Subramanian, M.S.

1987-01-01

Complexes of uranyl ion with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5(PMAP) and various oxo-donors such as aliphatic sulphoxides [R 2 SO, where R = i-C 5 H 11 (DISO), n-C 6 H 13 (DHSO), n-C 7 H 15 (DSSO), n-C 8 H 17 (DOSO), n-C 9 H 19 (DNSO), n-C 10 H 21 (DDSO), n-C 11 H 23 (DUDSO) and n-C 4 H 9 (DBUSO)] tributylphosphate (TBP) and tri-n-octyl phosphine oxide (TOPO) have been synthesised and characterized. Analytical data establish that they have the stoichiometry UO 2 (PMAP) 2 X where X is the oxo-donor. The IR spectra of the sulphoxide complexes in the S - O stretching region indicate that the ligands R 2 SO are O-bonded. The methyl protons of the pyrazole ring and acetyl group in the PMAP ligand are equivalent giving rise to a single sharp peak in the PMR spectra, whereas in the synergistic complexes with the oxo-donors, two deshielded peaks of equal intensity are observed which indicate the non-equivalence of the methyl groups. The peak which is more deshielded has been ascribed to the methyl of the acetyl group. The higher deshielding of these methyl protons arises due to the transfer of electron density to the metal atom on complexation. (author)

Synthesis, Characterization, and Variable-Temperature NMR Studies of Silver(I) Complexes for Selective Nitrene Transfer.

Science.gov (United States)

Huang, Minxue; Corbin, Joshua R; Dolan, Nicholas S; Fry, Charles G; Vinokur, Anastasiya I; Guzei, Ilia A; Schomaker, Jennifer M

2017-06-05

An array of silver complexes supported by nitrogen-donor ligands catalyze the transformation of C═C and C-H bonds to valuable C-N bonds via nitrene transfer. The ability to achieve high chemoselectivity and site selectivity in an amination event requires an understanding of both the solid- and solution-state behavior of these catalysts. X-ray structural characterizations were helpful in determining ligand features that promote the formation of monomeric versus dimeric complexes. Variable-temperature 1 H and DOSY NMR experiments were especially useful for understanding how the ligand identity influences the nuclearity, coordination number, and fluxional behavior of silver(I) complexes in solution. These insights are valuable for developing improved ligand designs.

Mono- and Dinuclear Manganese Carbonyls Supported by 1,8-Disubstituted (L = Py, SMe, SH) Anthracene Ligand Scaffolds.

Science.gov (United States)

Manes, Taylor A; Rose, Michael J

2016-06-06

Presented herein is a synthetic scheme to generate symmetric and asymmetric ligands based on a 1,8-disubstituted anthracene scaffold. The metal-binding scaffolds were prepared by aryl chloride activation of 1,8-dichloroanthracene using Suzuki-type couplings facilitated by [Pd(dba)2] as a Pd source; the choice of cocatalyst (XPhos or SPhos) yielded symmetrically or asymmetrically substituted scaffolds (respectively): namely, Anth-SMe2 (3), Anth-N2 (4), and Anth-NSMe (6). The ligands exhibit a nonplanar geometry in the solid state (X-ray), owing to steric hindrance between the anthracene scaffold and the coupled aryl units. To determine the flexibility and binding characteristics of the anthracene-based ligands, the symmetric scaffolds were complexed with [Mn(CO)5Br] to afford the mononuclear species [(Anth-SMe2)Mn(CO)3Br] (8) and [(Anth-N2)Mn(CO)3Br] (9), in which the donor moieties chelate the Mn center in a cis fashion. The asymmetric ligand Anth-NSMe (6) binds preferentially through the py moieties, affording the bis-ligated complex [(Anth-NSMe)2Mn(CO)3Br] (10), wherein the thioether-S donors remain unbound. Alternatively, deprotection of the thioether in 6 affords the free thiol ligand Anth-NSH (7), which more readily binds the Mn center. Complexation of 7 ultimately affords the mixed-valence Mn(I)/Mn(II) dimer of formula [(Anth-NS)3Mn2(CO)3] (11), which exhibits a fac-{Mn(CO)3} unit supported by a triad of bridging thiolates, which are in turn ligated to a supporting Mn(II) center (EPR: |D| = 0.053 cm(-1), E/|D| = 0.3, Aiso = -150 MHz). All of the metal complexes have been characterized by single-crystal X-ray diffraction, IR spectroscopy and NMR/EPR measurements-all of which demonstrate that the meta-linked, anthracene-based ligand scaffold is a viable approach for the coordination of metal carbonyls.

Molecular recognition of naphthalene diimide ligands by telomeric quadruplex-DNA: the importance of the protonation state and mediated hydrogen bonds.

Science.gov (United States)

Spinello, A; Barone, G; Grunenberg, J

2016-01-28

In depth Monte Carlo conformational scans in combination with molecular dynamics (MD) simulations and electronic structure calculations were applied in order to study the molecular recognition process between tetrasubstituted naphthalene diimide (ND) guests and G-quadruplex (G4) DNA receptors. ND guests are a promising class of telomere stabilizers due to which they are used in novel anticancer therapeutics. Though several ND guests have been studied experimentally in the past, the protonation state under physiological conditions is still unclear. Based on chemical intuition, in the case of N-methyl-piperazine substitution, different protonation states are possible and might play a crucial role in the molecular recognition process by G4-DNA. Depending on the proton concentration, different nitrogen atoms of the N-methyl-piperazine might (or might not) be protonated. This fact was considered in our simulation in terms of a case by case analysis, since the process of molecular recognition is determined by possible donor or acceptor positions. The results of our simulations show that the electrostatic interactions between the ND ligands and the G4 receptor are maximized in the case of the protonation of the terminal nitrogen atoms, forming compact ND G4 complexes inside the grooves. The influence of different protonation states in terms of the ability to form hydrogen bonds with the sugar-phosphate backbone, as well as the importance of mediated vs. direct hydrogen bonding, was analyzed in detail by MD and relaxed force constant (compliance constant) simulations.

Red-yellow electroluminescence, yellow-green photoluminescence of novel N, O donor ligands-chelated zirconium (IV) complexes

Energy Technology Data Exchange (ETDEWEB)

Shahroosvand, Hashem, E-mail: shahroos@znu.ac.ir [Chemistry Department, University of Zanjan, Zanjan (Iran, Islamic Republic of); Nasouti, Fahimeh [Chemistry Department, University of Zanjan, Zanjan (Iran, Islamic Republic of); Mohajerani, Ezeddin; Khabbazi, Amir [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

2013-03-15

In this paper, eight new zirconium complexes with 1,2,4,5-benzenetetracarboxylic acid (H{sub 4}btec), 1,10-phenanthroline (phen) and 4,7-diphenyl-1,10-phenanthroline (Bphen), were prepared and used as light emitting material in fabricated OLEDs. The structures of these complexes were characterized by UV-vis, FT-IR spectroscopy, {sup 1}H-NMR, CHN and ICP-AES. A yellow-green photoluminescence (PL) emission with a red shift compared to the PVK:PBD blend was observed. Devices with Zr complexes with the structure ITO/PEDOT:PSS/PVK:PBD/zirconium complex/Al emitted a yellow-red light originating from the Zr complexes. We believe that electroplex occurring at PVK-Zr complex interface is responsible for the red emission in the EL of the device. - Highlights: Black-Right-Pointing-Pointer Novel photoluminescence zirconium (IV) complexes with hole transport ligands are synthesized. Black-Right-Pointing-Pointer Yellow-green photoluminescence emission is shown red shift rather than PVK:PBD blend. Black-Right-Pointing-Pointer The control of the emission properties of OLED devices is explored by adding of {pi}-extended ligands such as Bphen. Black-Right-Pointing-Pointer El spectra are shown a red shift of the emission bands in respond to the addition of {Pi}-conjugated ligands. Black-Right-Pointing-Pointer Electroplex emission at PVK-Zr complex is proposed.

Thermal activation of nitrogen acceptors in ZnO thin films grown by MOCVD

Energy Technology Data Exchange (ETDEWEB)

Dangbegnon, J.K.; Talla, K.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth (South Africa)

2010-06-15

Nitrogen doping in ZnO is inhibited by spontaneous formation of compensating defects. Perfect control of the nitrogen doping concentration is required, since a high concentration of nitrogen could induce the formation of donor defects involving nitrogen. In this work, the effect of post-growth annealing in oxygen ambient on ZnO thin films grown by Metalorganic Chemical Vapor Deposition, using NO as both oxidant and nitrogen dopant, is studied. After annealing at 700 C and above, low-temperature photoluminescence shows the appearance of a transition at {proportional_to}3.23 eV which is interpreted as pair emission involving a nitrogen acceptor. A second transition at {proportional_to}3.15 eV is also discussed. This work suggests annealing as a potential means for p-type doping using nitrogen (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Synthesis and Crystal Structure of Dinuclear Cadmium(II) Complex with Dipodal Ligand

International Nuclear Information System (INIS)

Kang, Young Jin; Moon, Suk Hee; Byun, Jong Chul; Park, Ki Min

2010-01-01

the preparation and structural characterization of the discrete dinuclear cadmium(II) complex with the formula [Cd(μ 2 -Cl) 2 Cl 2 ]· 2 (H 2 O)·0.5(CH 3 OH)·0.5(CH 3 CN) obtained from the reaction of CdCl 2 ·2.5H 2 O and podal ligand with quinoline end-groups has been reported. In two cadmium ions are triply bridged by two chloride and one donor atoms of ligand L and adopt distorted pentagonal bipyramidal geometries with seven coordinations. It is notable that example of discrete dinuclear complex which one podal ligand accommodates simultaneously two metal ions is very rare. During the last four decades, the chemistry of macrocyclic and non-cyclic polyethers has attracted an increasing attention because of their selective complexation, cation transport and enzyme chemistry. In the field of coordination chemistry, generally, non-cyclic, crown-type polyether affords the low complexation ability because of its conformational freedom while macrocyclic polyethers such as 18-crown-6 show the excellent complexing ability

Atmospheric pollutant and other data from the TRIDENT and tower as part of the International Decade of Ocean Exploration (IDOE) from 1972-02-01 to 1972-09-01 (NCEI Accession 7300574)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Atmospheric pollutant and other data were collected from the TRIDENT and tower from 01 February 1972 to 01 September 1972. Data include trace metals in the...

Ligand-Controlled Synthesis of Azoles via Ir-Catalyzed Reactions of Sulfoxonium Ylides with 2-Amino Heterocycles.

Science.gov (United States)

Phelps, Alicia M; Chan, Vincent S; Napolitano, José G; Krabbe, Scott W; Schomaker, Jennifer M; Shekhar, Shashank

2016-05-20

An iridium-catalyzed method was developed for the synthesis of imidazo-fused pyrrolopyrazines. The presence or absence of a nitrogenated ligand controlled the outcome of the reaction, leading to simple β-keto amine products in the absence of added ligand and the cyclized 7- and 8-substituted-imidazo[1,2-a]pyrrolo[2,3-e]pyrazine products in the presence of ligand. This catalyst control was conserved across a variety of ylide and amine coupling partners. The substrate was shown to act as a ligand for the iridium catalyst in the absence of other ligands via NMR spectroscopy. Kinetic studies indicated that formation of the Ir-carbene was reversible and the slow step of the reaction. These mechanistic investigations suggest that the β-keto amine products form via an intramolecular carbene N-H insertion, and the imidazopyrrolopyrazines form via an intermolecular carbene N-H insertion.

New twists and turns for actinide chemistry. Organometallic infinite coordination polymers of thorium diazide

Energy Technology Data Exchange (ETDEWEB)

Monreal, Marisa J.; Seaman, Lani A.; Goff, George S.; Michalczyk, Ryszard; Morris, David E.; Scott, Brian L.; Kiplinger, Jaqueline L. [Los Alamos National Laboratory, Los Alamos, NM (United States)

2016-03-07

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

Implementation of STUD Pulses at the Trident Laser and Initial Results

Science.gov (United States)

Johnson, R. P.; Shimada, T.; Montgomery, D. S.; Afeyan, B.; Hüller, S.

2012-10-01

Controlling and mitigating laser-plasma instabilities such as stimulated Brillouin scattering, stimulated Raman scattering, and crossed-beam energy transfer is important to achieve high-gain inertial fusion using laser drivers. Recent theory and simulations show that these instabilities can be largely controlled using laser pulses consisting of spike trains of uneven duration and delay (STUD) by modulating the laser on a picosecond time scale [1,2]. We have designed and implemented a STUD pulse generator at the LANL Trident Laser Facility using Fourier synthesis to produce a 0.5-ns envelope of psec-duration STUD pulses using a spatial light modulator. Initial results from laser propagation tests and measurements as well as initial laser-plasma characterization experiments will be presented.[4pt] [1] B. Afeyan and S. H"uller, ``Optimal Control of Laser Plasma Instabilities using STUD pulses,'' IFSA 2011, P.Mo.1, to appear in Euro. Phys. J. Web of Conf. (2012).[2] S. H"uller and B. Afeyan, ``Simulations of drastically reduced SBS with STUD pulses,'' IFSA 2011, O.Tu8-1, to appear in Euro. Phys. J. Web of Conf. (2012).

Coordination compounds of cobalt (3), chromium (3) and vanadium (3) with s-methylthiosemicarbazone of salicylic aldehyde

Energy Technology Data Exchange (ETDEWEB)

Leovats, V.M.; Gehrbehlehu, N.V.; Tsanich, V.D. (AN Moldavskoj SSR, Kishinev. Inst. Khimii)

1982-04-01

Coordination compounds of trivalent cobalt, chromium and vanadium with S-methylthiosemicarbazone of salicylic aldehyde H/sub 2/L of (Co(HL)/sub 2/)XxnH/sub 2/O (X=Cl, Br, I, NO/sub 3/, ClO/sub 4/), (CoL(NH/sub 3/)/sub 3/)NO/sub 3/, (Co(HL)/sub 2/)/sub 2/(Co(NCS)/sub 4/)x2H/sub 2/O, (CoCl(DH)/sub 2/(H/sub 2/L))xH/sub 2/O, (Cr(HL)/sub 2/)XxnH/sub 2/O (X=Cl, NO/sub 3/), (V(HL)/sub 2/)Clx1/2H/sub 2/O, (M(HL)L)xnH/sub 2/O (M=Co, Cr, V) compositions are synthesized and investigated. It is shown, that H/sub 2/L behaves as a tridentate ligand at the expense of (O, N, N) set of donor atoms. The effective magnetic moment of the compounds is calculated.

Palladium and platinum complexes of 2-(2′-carboxyphenylazo)-4 ...

Indian Academy of Sciences (India)

Wintec

M = Pd and Pt), in which ligand 1 has been found to bind the metal centers in the tridentate fashion (2). The chemistry of these two complexes is described in this paper with special reference to their synthesis, structure and spectral properties.

Are drowned donors marginal donors? A single pediatric center experience.

Science.gov (United States)

Kumm, Kayla R; Galván, N Thao N; Koohmaraie, Sarah; Rana, Abbas; Kueht, Michael; Baugh, Katherine; Hao, Liu; Yoeli, Dor; Cotton, Ronald; O'Mahony, Christine A; Goss, John A

2017-09-01

Drowning, a common cause of death in the pediatric population, is a potentially large donor pool for OLT. Anecdotally, transplant centers have deemed these organs high risk over concerns for infection and graft dysfunction. We theorized drowned donor liver allografts do not portend worse outcomes and therefore should not be excluded from the donation pool. We reviewed our single-center experience of pediatric OLTs between 1988 and 2015 and identified 33 drowned donor recipients. These OLTs were matched 1:2 to head trauma donor OLTs from our center. A chart review assessed postoperative peak AST and ALT, incidence of HAT, graft and recipient survival. Recipient survival at one year between patients with drowned donor vs head trauma donor allografts was not statistically significant (94% vs 97%, P=.63). HAT incidence was 6.1% in the drowned donor group vs 7.6% in the control group (P=.78). Mean postoperative peak AST and ALT was 683 U/L and 450 U/L for drowned donors vs 1119 U/L and 828 U/L in the matched cohort. These results suggest drowned donor liver allografts do not portend worse outcomes in comparison with those procured from head trauma donors. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Imaging evaluation of potential donors in living-donor liver transplantation

International Nuclear Information System (INIS)

Low, G.; Wiebe, E.; Walji, A.H.; Bigam, D.L.

2008-01-01

Liver transplants, originally obtained from deceased donors, can now be harvested from living donors as well. This technique, called living-donor liver transplantation (LDLT), provides an effective alternative means of liver transplantation and is a method of expanding the donor pool in light of the demand and supply imbalance for organ transplants. Imaging plays an important role in LDLT programmes by providing robust evaluation of potential donors to ensure that only anatomically suitable donors with no significant co-existing pathology are selected and that crucial information that allows detailed preoperative planning is available. Imaging evaluation helps to improve the outcome of LDLT for both donors and recipients, by improving the chances of graft survival and reducing the postoperative complication rate. In this review, we describe the history of LDLT and discuss in detail the application of imaging in donor assessment with emphasis on use of modern computed tomography (CT) and magnetic resonance imaging (MRI) techniques

Gamete donation: parents' experiences of searching for their child's donor siblings and donor.

Science.gov (United States)

Freeman, T; Jadva, V; Kramer, W; Golombok, S

2009-03-01

This study investigates the new phenomenon of parents of donor offspring searching for and contacting their child's 'donor siblings' (i.e. donor offspring conceived by the same donor) and donor. Online questionnaires were completed by 791 parents (39% lone-mother, 35% lesbian-couple, 21% heterosexual-couple, 5% non-specified) recruited via the Donor Sibling Registry; a US-based international registry that facilitates contact between donor conception families who share the same donor. Data were collected on parents' reasons for searching for their child's donor siblings and/or donor, the outcome of these searches and parents' and their child's experiences of any resulting contact. Parents' principal motivation for searching for their child's donor siblings was curiosity and for their donor, enhancing their child's sense of identity. Some parents had discovered large numbers of donor siblings (maximum = 55). Most parents reported positive experiences of contacting and meeting their child's donor siblings and donor. This study highlights that having access to information about a child's donor origins is important for some parents and has potentially positive consequences. These findings have wider implications because the removal of donor anonymity in the UK and elsewhere means that increasing numbers of donor offspring are likely to seek contact with their donor relations in the future.

Construction of Polynuclear Lanthanide (Ln = Dy(III), Tb(III), and Nd(III)) Cage Complexes Using Pyridine-Pyrazole-Based Ligands: Versatile Molecular Topologies and SMM Behavior.

Science.gov (United States)

Bala, Sukhen; Sen Bishwas, Mousumi; Pramanik, Bhaskar; Khanra, Sumit; Fromm, Katharina M; Poddar, Pankaj; Mondal, Raju

2015-09-08

Employment of two different pyridyl-pyrazolyl-based ligands afforded three octanuclear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core. Relatively less common semirigid pyridyl-pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers. It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl-pyrazol. We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites. The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions. Alternating current (ac) susceptibility measurements of the two dysprosium complexes display frequency- and temperature-dependent out-of-phase signals in zero and 0.5 T direct current field, a typical characteristic feature of single-molecule magnet (SMM) behavior, indicating different energy reversal barriers due to different molecular topologies. Another aspect of this work is the occurrence of the not-so-common SMM behavior of the terbium complex, further confirmed by ac susceptibility measurement.

Peroxo complexes of molybdenum(VI), tungsten(VI), uranium(VI), zirconium(IV) and thorium(IV) ions containing tridentate Schiff bases derived from salicylaldehyde and amino acids

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Khan, A.R.

1997-01-01

The synthesis of peroxo complexes of molybdenum(VI), tungsten(VI), uranium(VI), zirconium(IV), thorium(IV) and their possible oxygen transfer reactions is presented. An attempt has also been made to study the size of the metal ions and the electronic effect derived from the tridentate Schiff bases on the v 1 (O-O) mode of the complexes in their IR spectra

Interaction of d(10) metal ions with thioether ligands: a thermodynamic and theoretical study.

Science.gov (United States)

Melchior, Andrea; Peralta, Elena; Valiente, Manuel; Tavagnacco, Claudio; Endrizzi, Francesco; Tolazzi, Marilena

2013-05-07

Thermodynamic parameters of complex formation between d(10) metal ions, such as Zn(2+), Cd(2+), Hg(2+) and Ag(+), and the macrocyclic thioether 1,4,7-trithiacyclononane ([9]AneS3) or the monodentate diethylsulfide (Et(2)S), in acetonitrile (AN) at 298.15 K, were studied by a systematic methodology including potentiometry, calorimetry and polarography. [9]AneS3 is able to form complexes with all the target cations, Et(2)S only reacts with Hg(2+) and Ag(+). Mononuclear ML(j) (j = 1, 2) complexes are formed with all the metal ions investigated, where the affinity order is Hg(2+) > Ag(+) > Cd(2+) ≈ Zn(2+) when L = [9]AneS3 and Hg(2+) > Ag(+) when L = Et(2)S. Enthalpy and entropy values are generally negative, as a consequence of both metal ion interactions with neutral ligands, the reagents' loss of degrees of freedom and the release of solvating molecules. DFT calculations on the complexes formed with [9]AneS3 in vacuum and in AN are also carried out, to correlate experimental and theoretical thermodynamic values and to highlight the interplay between the direct metal-thioether interaction and the solvation effects. Trends obtained for the stability constants and enthalpies of the 1 : 1 and 1 : 2 complexes in solvent well reproduce the experimental ones for all the divalent metal ion complexes with [9]AneS3 and indicate the release of 3 AN molecules in the formation of each consecutive octahedral complex. In addition, calculated and experimental values for Ag(+) complex formation in solution suggest that in AgL(2) species [9]AneS3 ligands are not both tridentate.

Synthesis and characterization of 6,6’-bis(2-hydroxyphenyl)-2,2’-bipyridine ligand and its interaction with ct-DNA

International Nuclear Information System (INIS)

Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd

2015-01-01

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by 1 H, 2D cosy and 13 C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant K b = 1.19 × 10 3 ± 0.08 M −1

Improved survival of acute lymphoblastic leukemia patients of HLA-A3/11 absent for donor KIR3DL2 after non-T-cell depleted HLA-identical sibling hematopoietic stem cells transplantation

Directory of Open Access Journals (Sweden)

farhad shahsavar

2011-08-01

Conclusion: These data indicate that the absence of HLA class I ligand in the recipient for donor-inhibitory KIR can be a prognostic factor for transplantation outcomes in non-T-cell depleted HLA-identical sibling hematopoietic stem-cell transplantation and that the lack of HLA-A3/11 for donor KIR3DL2 can contribute to improved survival for patients with ALL.

Multipurpose 10 in. manipulator-based optical telescope for Omega and the Trident laser facilities

International Nuclear Information System (INIS)

Oertel, J.A.; Murphy, T.J.; Berggren, R.R.; Faulkner, J.; Schmell, R.; Little, D.; Archuleta, T.; Lopez, J.; Velarde, J.; Horton, R.F.

1999-01-01

We have recently designed and are building a telescope which acts as an imaging light collector relaying the image to an optical table for experiment dependent analysis and recording. The expected primary use of this instrument is a streaked optical pyrometer for witness plate measurements of the hohlraum drive temperature. The telescope is based on the University of Rochester close-quote s 10 in. manipulator (TIM) which allows compatibility between Omega, Trident, and the NIF lasers. The optics capture a f/7 cone of light, have a field of view of 6 mm, have a spatial resolution of 5 - 7 μm per line pair at the object plane, and are optimized for operation at 280 nm. The image is at a magnification of 11.7x, which is convenient for many experiments, but can be changed using additional optics that reside outside the TIM. copyright 1999 American Institute of Physics

Solid state structure of thorium(IV) complexes with common aminopoly-carboxylate ligands

International Nuclear Information System (INIS)

Thuery, Pierre

2011-01-01

The crystal structures of the complexes formed by reaction of thorium(IV) nitrate with iminodiacetic acid (H 2 IDA), nitrilotriacetic acid (H 3 NTA), and ethylenediaminetetraacetic acid (H 4 EDTA) under hydrothermal conditions are reported. In [Th(HIDA) 2 (C 2 O 4 )].H 2 O (1), the metal atom is chelated by two carboxylate groups from two HIDA - anions and by two oxalate ligands formed in situ; two additional oxygen atoms from two more HIDA - anions complete the ten-coordinate environment of bi-capped square anti-prismatic geometry. The uncoordinated nitrogen atom is protonated and involved in hydrogen bonding. Two different ligands are present in [Th(NTA)(H 2 NTA)(H 2 O)].H 2 O (2), one of them being a O 3 ,N-chelating tri-anion which acts also as a bridge toward two neighboring metal ions, and the other being a bis-monodentate bridging species with an uncoordinated carboxylic arm and a central ammonium group. An aqua ligand completes the nine-coordinated, capped square anti-prismatic metal environment. The EDTA 4- anion in [Th(EDTA)(H 2 O)].2H 2 O (3) is chelating through one oxygen atom from each carboxylate group and the two nitrogen atoms, as in a previously reported molecular complex. Two carboxylate groups are bridging, which, with the addition of an aqua ligand, gives a capped square anti-prismatic coordination polyhedron. Aminopoly-carboxylate ligands have been much investigated in relation with actinide decorporation and nuclear wastes management studies, and the present results add to the structural information available on their complexes with thorium(IV), which has mainly been obtained up to now by extended X-ray absorption fine structure (EXAFS) spectroscopy. In particular, the bridging (non-chelating) coordination mode of H 2 NTA - is a novel feature in this context. All three complexes crystallize as two-dimensional assemblies and are thus novel examples of thorium-organic coordination polymers. (author)

[Nitrogen oxide is involved in the regulation of the Fe-S cluster assembly in proteins and the formation of biofilms by Escherichia coli cells].

Science.gov (United States)

Vasil'eva, S V; Streltsova, D A; Starostina, I A; Sanina, N A

2013-01-01

The functions of nitrogen oxide (NO) in the regulation of the reversible processes of Fe-S cluster assembly in proteins and the formation of Escherichia coli biofilms have been investigated. S-nitrosoglutathione (GSNO) and crystalline nitrosyl complexes of iron with sulfur-containing aliphatic ligands cisaconite (CisA) and penaconite have been used as NO donors for the first time. Wild-type E. coli cells of the strain MC4100, mutants deltaiscA and deltasufA, and the double paralog mutant deltaiscA/sufA with deletions in the alternative pathways of Fe2+ supply for cluster assembly (all derived from the above-named strain) were used in this study. Plankton growth of bacterial cultures, the mass of mature biofilms, and the expression of the SoxRS[2Fe-2S] regulon have been investigated and shown to depend on strain genotype, the process of Fe-S cluster assembly in iron-sulfur proteins, NO donor structure, and the presence of Fe2+ chelator ferene in the incubation medium. The antibiotic ciprofloxacine (CF) was used as an inhibitor of E. coli biofilm formation in the positive control. NO donors regulating Fe-S cluster assembly in E. coli have been shown to control plankton growth of the cultures and the process of mature biofilm formation; toxic doses of NO caused a dramatic (3- to 4-fold) stimulation of cell entry into biofilms as a response to nitrosative stress; NO donors CisA and GSNO in physiological concentrations suppressed the formation of mature biofilms, and the activity of these compounds was comparable to that of CE Regulation of both Fe-S cluster assembly in iron-sulfur proteins and biofilm formation by NO is indicative of the connection between these processes in E. coli.

Associations of health status with subsequent blood donor behavior-An alternative perspective on the Healthy Donor Effect from Donor InSight

NARCIS (Netherlands)

van den Hurk, Katja; Zalpuri, Saurabh; Prinsze, Femmeke J.; Merz, Eva-Maria; de Kort, Wim L. A. M.

2017-01-01

In donor health research, the 'Healthy Donor Effect' (HDE) often biases study results and hampers their interpretation. This refers to the fact that donors are a selected 'healthier' subset of a population due to both donor selection procedures and self-selection. Donors with long versus short donor

Synthesis, characterization and biological evaluation of [{sup 188}Re(N)(cys{approx})(PNP)]{sup +/0} mixed-ligand complexes as prototypes for the development of {sup 188}Re(N)-based target-specific radiopharmaceuticals

Energy Technology Data Exchange (ETDEWEB)

Thieme, Stefan [Institute of Radiopharmacy, Forschungszentrum Dresden Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Agostini, Stefania [Department of Pharmaceutical Sciences, University of Padua, Via Marzolo 5, 35131 Padova (Italy); Bergmann, Ralf; Pietzsch, Jens; Pietzsch, Hans-Juergen [Institute of Radiopharmacy, Forschungszentrum Dresden Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Carta, Davide; Salvarese, Nicola [Department of Pharmaceutical Sciences, University of Padua, Via Marzolo 5, 35131 Padova (Italy); Refosco, Fiorenzo [ICIS-CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Bolzati, Cristina, E-mail: bolzati@icis.cnr.i [Department of Pharmaceutical Sciences, University of Padua, Via Marzolo 5, 35131 Padova (Italy); ICIS-CNR, Corso Stati Uniti 4, 35127 Padova (Italy)

2011-04-15

We report on an efficient procedure for the preparation of [{sup 188}Re(N)(PNP)]-based complexes (where PNP is diphosphinoamine) useful in the development of target-specific radiopharmaceuticals. The radiochemical yield of the compounds was optimized considering such reaction parameters as nature of the nitrido nitrogen donor, reaction times and pH level. The chemical identity of the {sup 188}Re agents was determined by high-performance liquid chromatography comparison with the corresponding well-characterized cold Re compounds. {sup 188}Re(N) mixed compounds have been evaluated with regard to stability toward transchelation with GSH and degradation by serum enzymes. The clearance of selected radiocompounds from normal tissues and their in vivo stability were evaluated in rats by biodistribution and imaging studies. [{sup 188}Re(N)(cys{approx})(PNP)]{sup +/0} mixed-ligand compounds were efficiently prepared in aqueous solution from perrhenate using a multistep procedure based on the preliminary formation of the labile {sup 188}Re{sup III}-EDTA species, which easily undergo oxidation/ligand exchange reaction to afford the [{sup 188}Re{sup V{identical_to}}N]{sup 2+} core in the presence of dithiocarbazate. The final mixed-ligand compounds were obtained, at 100{sup o}C, by adding the two bidentate ligands to the buffered [{sup 188}Re{sup V{identical_to}}N]{sup 2+} solution (pH 3.2-3.6). However, a relatively high amount of cys{approx} ligand was required to obtain a quantitative radiochemical yield. The complexes were stable toward reoxidation to perrhenate and ligand exchange reactions. In vivo studies showed rapid distribution and elimination of the complexes from the body. No specific uptakes in sensitive tissues/organs were detected. A positive correlation of the distribution of the complexes estimated with biodistribution studies (%ID) and with micro-SPECT semiquantification imaging analysis (standard uptake values) was observed. These results support the

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

BIG was formed by the reaction of Cu(ClO₄)₂ ·6H₂O and tridentate benzimidazole-glycine conjugate ligand, 2-((1H-benzimidazol- 2-yl)methylamino) acetic acid, BIGH and its structure has been determined by IR, UV, powder XRD, VSM, CV, ...

Synthesis, characterization, biological and electrical conductivity ...

African Journals Online (AJOL)

All the complexes have been characterized on the basis of elemental analyses, magnetic susceptibility measurement, electronic and IR spectra and thermogravimetric analysis. The IR spectral data suggested that the ligands behave as dibasic tridentate moiety towards the central metal ion coordinating through phenolic ...

The influence of stereoisomerism on the pharmacokinetics of Tc radiopharmaceuticals

Energy Technology Data Exchange (ETDEWEB)

Hansen, L.; Taylor, A. [Atlanta, Emory Univ. School of Medicine, GA (United States). Dept. of Chemistry; Marzilli, L.G. [Atlanta, Emory Univ. School of Medicine, GA (United States). Dept. of Radiology

1998-12-01

The influence of stereoisomerism on the pharmacokinetics of Tc mono-oxo complexes is reviewed. Tc(V) mono-oxo complexes formed with N/S ligands have four donor groups from the ligands in an equatorial plane; the oxo ligand coordinates in an axial position. Stereoisomerism in Tc(V) mono-oxo complexes can be centered within the ligand (carbon atom in the chelate ring of ligating nitrogen of amine donors) or at the Tc. The metal center becomes chiral when an equatorial ligand has a head and a tail (i.e. the two ends of the ligand differ). All types of stereocenter can produce significantly different pharmacokinetic profiles for individual isomers. Thus, biological evaluation of separated stereoisomers is necessary to identify the optimal stereochemical configuration, particularly for radiopharmaceuticals targeted to receptor molecules with low specificity. Because of inter species variation, there is ultimately no substitute for human testing. Although it is possible that the increase in nonspecific binding of agents incorporating L- vs D-amino acids may more than offset any increased receptor binding, much more information is needed. Stereochemical factors can also lead to unpredictable differences in coordination geometry and thermodynamic preference of a single isomer; thus chemical characterization of stereo-isomers continues to be an important component of radiopharmaceutical development.

Control of charge transfer by conformational and electronic effects: Donor-donor and donor-acceptor phenyl pyrroles

International Nuclear Information System (INIS)

Neubauer, Antje; Bendig, Juergen; Rettig, Wolfgang

2009-01-01

Derivatives of N-pyrrolobenzene with a para-donor and a para-acceptor substituent on the benzene ring are compared. It is shown that by a suitable increase of the donor strength of the pyrrolo group, CT fluorescence can be achieved even for donor-donor-substituted benzenes. The ICT emission for sterically hindered compounds is more forbidden than that of unhindered phenyl pyrroles. This suggests conformational effects which induce a narrower twist angle distribution around a perpendicular minimum in the excited state.

Synthesis and stereochemical assignments of diastereomeric Ni(II complexes of glycine Schiff base with (R-2-(N-{2-[N-alkyl-N-(1-phenylethylamino]acetyl}aminobenzophenone; a case of configurationally stable stereogenic nitrogen

Directory of Open Access Journals (Sweden)

Hiroki Moriwaki

2014-02-01

Full Text Available A family of chiral ligands derived from α-phenylethylamine and 2-aminobenzophenone were prepared by alkylation of the nitrogen atom. Upon reaction with glycine and a Ni(II salt, these ligands were transformed into diastereomeric complexes, as a result of the configurational stability of the stereogenic nitrogen atom. Different diastereomeric ratios were observed depending on the substituent R introduced in the starting ligand, and stereochemical assignments were based on X-ray analysis, along with NMR studies and optical rotation measurements.

Xafs studies on actinide-pyridine-diamide complexes for development of an innovative separation process

International Nuclear Information System (INIS)

Hideaki, Shiwaku; Tsuyoshi, Yaita; Tohru, Kobayashi; Masahiko, Numakura; Tsuyoshi, Yaita; Shinichi, Suzuki; Yoshihiro, Okamoto

2007-01-01

We have been studying the bond properties and the structures of actinide (An) and lanthanide (Ln) complexes in detail using several kinds of X-ray analyses by synchrotron radiation in order to elucidate the ionic recognition mechanism of organic ligands. Generally, an oxygen donor type ligand separates both An and Ln from solutions of spent fuel or high level radioactive waste. Separation ability of this type of ligand for An and Ln follows the order of the surface charge density of an ion, i.e., An 4+ > AnO 2 2+ > An 3+ = Ln 3+ > AnO 2+ and/or a few structural factors. Therefore, this type of ligand is ineffective for the separation of An 3+ and Ln 3+ due to their similar chemical properties. Recently, new extractants like aromatic N-donor ligands have been developed using the preference of soft-donors to achieve the An 3+ /Ln 3+ separation. However, aromatic N-donor ligands often show a few problems such as protonation. In this developing process, we synthesized a new type of ligand, N,N'-dimethyl-N,N'-diphenyl-pyridine-2,6-carboxy-amide (DMDPh-PDA). The PDA is hybrid type ligand having oxygen and nitrogen as donor atoms and follows a unique separation order, i.e., An 4+ > An 3+ > AnO 2 2+ > Ln 3+ > AnO 2 + , probably arising from the combined effects of covalent bonding and steric hindrance. Hence, clarification of any ionic recognition mechanism of the PDA is very interesting from the view point of structural analysis. In this presentation, we will show XAFS results of An and Ln complexes with PDA in solution and discuss separation mechanism of An and Ln by PDA. Various kinds of complexes between Ln/An and PDA were prepared for XAFS analysis. The Ln complexes were measured in transmission mode at the K absorption edge on the BL11XU at SPring-8. On the other hand, the U complexes were measured in fluorescence mode at the L III absorption edge on the BL-27B at Photon Factory, High-energy Accelerator Research Organization (KEK). (authors)

Fission product interactions with nitrogen donor ligands used for spent nuclear fuel treatment

Czech Academy of Sciences Publication Activity Database

Aneheim, E.; Grüner, Bohumír; Ekberg, C.; Foreman, M.R.S.J.; Hájková, Zuzana; Löfström-Engdahl, E.; Drew, M. G. B.; Hudson, M.J.

2013-01-01

Roč. 50, č. 1 (2013), s. 154-163 ISSN 0277-5387 R&D Projects: GA MŠk(CZ) 7G08073 Grant - others:ACSEPT(XE) FP7-CP-2007-211 267 Institutional support: RVO:61388980 Keywords : BTBP * palladium * complexation * water solubility Subject RIV: CA - Inorganic Chemistry Impact factor: 2.047, year: 2013

Experiences of offspring searching for and contacting their donor siblings and donor.

Science.gov (United States)

Jadva, Vasanti; Freeman, Tabitha; Kramer, Wendy; Golombok, Susan

2010-04-01

This study investigates a new phenomenon whereby individuals conceived by donor insemination are searching for and contacting their donor and/or 'donor siblings' (i.e. donor offspring conceived by the same donor who are their genetic half siblings). On-line questionnaires were completed by members of the Donor Sibling Registry (DSR), a US-based registry that facilitates contact between donor conception families who share the same donor. Of the 165 donor offspring who completed the survey, 15% were searching for their donor siblings, 13% were searching for their donor, and 64% were searching for both. Differences were found according to family type and age of disclosure. Fewer offspring from heterosexual couple families had told their father about their search when compared with offspring from lesbian couple families who had told their co-parent. Offspring who had found out about their conception after age 18 were more likely to be searching for medical reasons, whereas those who had found out before age 18 tended to be searching out of curiosity. Some offspring had discovered large numbers of half siblings (maximum=13). The majority of offspring who had found their donor relations reported positive experiences and remained in regular contact with them. Copyright (c) 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Chemistry of oxovanadium(IV) bound to tetradentate ONNO donors; influence of axial coordination on the V-Osub(1) bond

International Nuclear Information System (INIS)

Maity, A.; Ghosh, S.

1992-01-01

Chelating behaviour of some tetradentate ONNO donors from q-aminobenzoylhydrazide and some diketones towards oxo-vanadium(IV) ion is reported. The donors react with oxometal cation depending on the pH of the reaction medium. The product containing the neutral keto and the binegative enol form of the donor have the formulae [Vo(H 2 L)(SO 4 )](at pH 3.0)(1) and [VO(L)(H 2 O)] (at pH 6.0) (2) respectively [H 2 L=(2-NH 2 )C 6 H 4 CONH: C(R).(CH 2 ) m C(R) : NNH CO.C 6 H 4 (2-NH 2 ); H 2 L=H 2 DA(R=CH 3 , m=0), H 2 BA(R=C 6 H 5 , m=0), H 2 AA(R=CH 3 , m=2)]. Both (1) and (2) react with a neutral monodentate donor B(B=pyridine, aniline etc.) yielding mixed-ligand complexes [VO(L)(B)]. Influence of the axial coordination on the V-Osub((1)) bond is discussed and a monomeric distorted octahedral donor environment for the oxovanadium(IV) ion has been suggested. (author). 2 refs., 2 tabs., 3 figs

New donor-acceptor-donor molecules based on quinoline acceptor unit with Schiff base bridge: synthesis and characterization

Energy Technology Data Exchange (ETDEWEB)

Kotowicz, Sonia [Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice (Poland); Siwy, Mariola [Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Str., 41-819 Zabrze (Poland); Filapek, Michal; Malecki, Jan G. [Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice (Poland); Smolarek, Karolina; Grzelak, Justyna; Mackowski, Sebastian [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, 5 Grudziadzka Str., 87-100 Torun (Poland); Slodek, Aneta, E-mail: aneta.slodek@us.edu.pl [Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice (Poland); Schab-Balcerzak, Ewa, E-mail: ewa.schab-balcerzak@us.edu.pl [Institute of Chemistry, University of Silesia, 9 Szkolna Street, 40-006 Katowice (Poland); Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Str., 41-819 Zabrze (Poland)

2017-03-15

Three solution-processable small organic molecules bearing quinoline as electron-accepting moiety were synthesized via condensation reaction of novel 6-amino-2-(2,2’-bithiophen-5-yl)-4-phenylquinoline with 2,2’-bithiophene-5-carboxaldehyde, 9-ethyl-9H-carbazole-3-carbaldehyde and 9-phenanthrenecarboxaldehyde. The presence of alternating electron-donating and accepting units results in a donor-acceptor-donor architecture of these molecular systems. Thermal, photophysical, and electrochemical properties of these small molecules were examined and the experimental results were supported by the density functional theory calculations. The obtained molecular systems exhibited high thermal stability with decomposition temperatures (5% weight loss) exceeding 330 °C in nitrogen atmosphere. It was found, based on DSC measurements, that investigated Schiff bases form amorphous material with glass transition temperatures between 88 and 190 °C. They also showed a UV–vis absorption in the range of 250–500 nm both in solution and in solid state as film and blend with PMMA and PVK. Photoluminescence measurements revealed moderately strong blue-light emission of the imines in solution as well as in PMMA blend with quantum yields in the range of 2–26%. In the case of imines dispersed in PVK matrix the emission of green light was mainly observed. In addition, when mixed with plasmonically active silver nanowires, the compounds exhibit relatively strong electroluminescence signal, associated with plasmonics enhancement, as evidenced by high-resolution photoluminescence imaging. The energy band gap estimated based on cyclic voltammetry was between 2.38 and 2.61 eV. - Highlights: • New Schiff bases possess donor-acceptor-imine-bridge-donor architecture were synthesized and examined. • Thorough characterization of optical and electrochemical properties of novel Schiff bases has been carried out. • Optical and electrochemical measurements were compared with DFT

Synthesis and characterization of nickel(II), cobalt(II), copper(II), manganese(II), zinc(II), zirconium(IV), dioxouranium(VI) and dioxomolybdenum(VI) complexes of a new Schiff base derived from salicylaldehyde and 5-methylpyrazole-3-carbohydrazide

International Nuclear Information System (INIS)

Syamal, A.; Maurya, M.R.

1986-01-01

Synthesis of a new Schiff base derived from salicylaldehyde and 5-methylpyrazole-3-carbohydrazide, and its coordination compounds with nickel(II), cobalt(II), copper(II), manganese(II), zinc(II), zirconium(IV), dioxouranium(VI) and dioxomolybdenum(VI) are described. The ligand and the complexes have been characterized on the basis of analytical, conductance, molecular weight, i.r., electronic and n.m.r. spectra and magnetic susceptibility measurements. The stoichiometries of the complexes are represented as NiL . 3H 2 O, CoL . 2H 2 O, CuL, MnL . 2H 2 O, ZnL . H 2 O, Zr(OH) 2 (LH) 2 , Zr(OH) 2 L . 2MeOH, UO 2 L . MeOH and MoO 2 L . MeOH (where LH 2 =Schiff base). The copper(II) complex shows a subnormal magnetic moment due to antiferromagnetic exchange interaction while the nickel(II), cobalt(II) and manganese(II) complexes show normal magnetic moments at room temperature. The i.r. and n.m.r. spectral studies show that the Schiff base behaves as a dibasic and tridentate ligand coordinating through the deprotonated phenolic oxygen, enolic oxygen and azomethine nitrogen. (orig.)

Thermodynamics of the complex formation between thorium(IV) and some polydentate ligands in aqueous solution

International Nuclear Information System (INIS)

Di Bernado, P.; Cassol, A.; Tomat, G.; Bismondo, A.; Magon, L.

1983-01-01

The changes in free energy, enthalpy, and entropy for the formation of thorium(IV)-oxydiacetate, -iminodiacetate, -thiodiacetate, and -succinate complexes have been determined by potentiometric and calorimetric titrations at 25 deg C in aqueous 1 mol dm - 3 sodium perchlorate. All the ligands form 1:1 chelate complexes with the thorium(IV) ion the stability of which is dependent on both the chelate ring dimensions and the nature of the donor group in the chain. The order of the relative stabilities (iminodiacetate > oxydiacetate > thiodiacetate > succinate) is mainly dependent on the reaction enthalpies, since the δS values are close to each other. In the thorium(IV)-oxydiacetate system the maximum number of three ligands for every metal ion was reached. Because of precipitation of solid compounds in the other systems, it was only possible to define complexes with a lower number of co-ordinated ligands: two for succinate and thiodiacetate, and one for iminodiacetate. Owing to the lower stability of the chelate ring of thiodiacetate and succinate complexes and the high basicity of the amino-group of iminodiacetate, these ligands form also unchelated protonated complexes. (author)

Design and synthesis of ruthenium(II) OCO pincer type NHC ...

Indian Academy of Sciences (India)

The tridentate nature of the tBu(OCO)2− ligand as well as some level of steric protection ... our previous results of ruthenium(II) o-hydroxyaryl sub- stituted bidentate NHC ...... (a) Ribelin T, Katz C E, English D G, Smith S,. Manukyan A K, Day ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

The analysis revealed that the complexes possess a distorted octahedral geometry with the ligand coordinating in a uni-negative tridentate ONS fashion. The catalytic activity of complexes towards some C–C coupling reactions (viz., Kumada-Corriu, Suzuki-Miyaura and Sonogashira) has been examined. The complexes ...

A novel extended architecture with 4 6·6 4 topology based on mixed-valence Wells-Dawson arsenotungstate and mixed-ligand Cu(I) units

Science.gov (United States)

Tong, Ruizhan; Ren, Xiaoyu; Li, Zuoxi; Liu, Bin; Hu, Huaiming; Xue, Ganglin; Fu, Feng; Wang, Jiwu

2010-09-01

A novel inorganic-organic hybrid compound based on mixed-valence Wells-Dawson arsenotungstate and mixed-ligand Cu(I) units, Cu 8I(imi) 4(bpy) 6(H 2O)[As 2VW 2VW 16VlO 62]·2H 2O ( 1) (bpy=4,4'-bipydine; imi=imidazole), has been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, luminescent spectrum and single crystal X-ray diffraction. Single-crystal X-ray diffraction revealed that four terminal and three bridging oxygen atoms of the Wells-Dawson cluster are coordinated to Cu(I) ions and form an unprecedented hepta-supporting polyoxometalate. The functionalized arsenotungstates are further connected by two kinds of tridentate linkers, Imi-Cu-(bpy)-Cu-(bpy)-Cu-(bpy)-Cu-Imi and Imi-Cu-(bpy)-Cu-(bpy)-Cu-H 2O, to construct a 3D framework with 4 6·6 4 topology. The hybrid material has an intense emission at about 397 nm.

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes† †Electronic supplementary information (ESI) available: LIFDI-MS spectra and additional NMR spectra. See DOI: 10.1039/c4sc03103b

Science.gov (United States)

Beele, Björn B.; Geist, Andreas; Müllich, Udo; Kaden, Peter; Panak, Petra J.

2015-01-01

C5-BPP is a highly efficient N-donor ligand for the separation of trivalent actinides, An(iii), from trivalent lanthanides, Ln(iii). The molecular origin of the selectivity of C5-BPP and many other N-donor ligands of the BTP-type is still not entirely understood. We present here the first NMR studies on C5-BPP Ln(iii) and An(iii) complexes. C5-BPP is synthesized with 10% 15N labeling and characterized by NMR and LIFDI-MS methods. 15N NMR spectroscopy gives a detailed insight into the bonding of C5-BPP with lanthanides and Am(iii) as a representative for trivalent actinide cations, revealing significant differences in 15N chemical shift for coordinating nitrogen atoms compared to Ln(iii) complexes. The temperature dependence of NMR chemical shifts observed for the Am(iii) complex indicates a weak paramagnetism. This as well as the observed large chemical shift for coordinating nitrogen atoms show that metal–ligand bonding in Am(C5-BPP)3 has a larger share of covalence than in lanthanide complexes, confirming earlier studies. The Am(C5-BPP)3 NMR sample is furthermore spiked with Cm(iii) and characterized by time-resolved laser fluorescence spectroscopy (TRLFS), yielding important information on the speciation of trace amounts of minor complex species. PMID:29560242

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes.

Science.gov (United States)

Adam, Christian; Beele, Björn B; Geist, Andreas; Müllich, Udo; Kaden, Peter; Panak, Petra J

2015-02-01

C5-BPP is a highly efficient N-donor ligand for the separation of trivalent actinides, An(iii), from trivalent lanthanides, Ln(iii). The molecular origin of the selectivity of C5-BPP and many other N-donor ligands of the BTP-type is still not entirely understood. We present here the first NMR studies on C5-BPP Ln(iii) and An(iii) complexes. C5-BPP is synthesized with 10% 15 N labeling and characterized by NMR and LIFDI-MS methods. 15 N NMR spectroscopy gives a detailed insight into the bonding of C5-BPP with lanthanides and Am(iii) as a representative for trivalent actinide cations, revealing significant differences in 15 N chemical shift for coordinating nitrogen atoms compared to Ln(iii) complexes. The temperature dependence of NMR chemical shifts observed for the Am(iii) complex indicates a weak paramagnetism. This as well as the observed large chemical shift for coordinating nitrogen atoms show that metal-ligand bonding in Am(C5-BPP) 3 has a larger share of covalence than in lanthanide complexes, confirming earlier studies. The Am(C5-BPP) 3 NMR sample is furthermore spiked with Cm(iii) and characterized by time-resolved laser fluorescence spectroscopy (TRLFS), yielding important information on the speciation of trace amounts of minor complex species.

Synthesis, Characterization, and Antibacterial Studies of Mixed Ligand Dioxouranium Complexes with 8-Hydroxyquinoline and Some Amino Acids

Science.gov (United States)

Patil, Sunil S.; Thakur, Ganesh A.; Shaikh, Manzoor M.

2011-01-01

Mixed ligand complexes of dioxouranium (VI) of the type [UO2(Q)(L)·2H2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and amino acids (HL) such as L-threonine, L-tryptophan, and L-isoleucine as secondary ligands. The metal complexes have been characterized by elemental analysis, electrical conductance, magnetic susceptibility measurements, and spectral and thermal studies. The electrical conductance studies of the complexes indicate their nonelectrolytic nature. Magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intraligand and charge transfer transitions, respectively. Bonding of the metal ion through N- and O-donor atoms of the ligands is revealed by IR studies, and the chemical environment of the protons is confirmed by NMR studies. The thermal analysis data of the complexes indicate the presence of coordinated water molecules. The agar cup and tube dilution methods have been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus, C. diphtheriae, S. typhi, and E. coli. PMID:22389843

The Use of Electron Donors to Increase Stereospecificity in Ziegler-Natta Propylene Polymerization

Directory of Open Access Journals (Sweden)

Farshid Nouri-Ahangarani

2016-05-01

Full Text Available Different chemical components in traditional Ziegler–Natta catalytic system include: (1 titanium and vanadium containing compounds, mostly TiCl4, as an active centre, (2 trialkylaluminium-based Lewis acid compounds, especially triethylaluminium, as precatalyst and alkylating agent, and (3 inorganic compounds, specifically MgCl2 and silica, as catalyst supports. Besides these compounds, shortly after the first discovery of Ziegler-Natta catalysts, electron donors have been considered as the key components for MgCl2-supported Ziegler-Natta catalysts, as they improve the stereospecificity and activity of these types of catalysts. Most electron donor compounds have oxygen atom and only a few contain nitrogen atom in their structure. Starting from benzoate for third-generation Ziegler–Natta catalysts, the discovery of new donors has always updated the performance of Ziegler–Natta catalysts. Since the first discovery of these compounds numerous efforts have been devoted in both industry and academic laboratories, not only to discover new electron donors but also to understand their roles in Ziegler–Natta olefin polymerization and suitable MgCl2-alcohol adducts formation. This article reviews the history of such research and development efforts. The first part of the article describes the historical developments of catalyst, with a special focus on donors of industrial importance, followed by an account given on recent trends in the latest donors developed. The next part of the article covers the historical progress toward mechanistic understanding of how donors improve the performance of Ziegler–Natta catalysts and how they undergo decomposition by interaction with Lewis acidic species such as the AlEt3 and TiCl.

A two-dimensional layered Cd(II) coordination polymer with a three-dimensional supramolecular architecture incorporating mixed multidentate N- and O-donor ligands.

Science.gov (United States)

Huang, Qiu-Ying; Su, Ming-Yang; Meng, Xiang-Ru

2015-06-01

The combination of N-heterocyclic and multicarboxylate ligands is a good choice for the construction of metal-organic frameworks. In the title coordination polymer, poly[bis{μ2-1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole-κ(2)N(3):N(4)}(μ4-butanedioato-κ(4)O(1):O(1'):O(4):O(4'))(μ2-butanedioato-κ(2)O(1):O(4))dicadmium], [Cd(C4H4O4)(C9H8N6)]n, each Cd(II) ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from three carboxylate groups of three succinate (butanedioate) ligands and two N atoms from two 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) ligands. Cd(II) ions are connected by two kinds of crystallographically independent succinate ligands to generate a two-dimensional layered structure with bimt ligands located on each side of the layer. Adjacent layers are further connected by hydrogen bonding, leading to a three-dimensional supramolecular architecture in the solid state. Thermogravimetric analysis of the title polymer shows that it is stable up to 529 K and then loses weight from 529 to 918 K, corresponding to the decomposition of the bimt ligands and succinate groups. The polymer exhibits a strong fluorescence emission in the solid state at room temperature.

Structural studies of lanthanide nitrate-N,N'-dimethyl-N,N'-diphenylpyridine-2,6-dicarboxyamide complexes

International Nuclear Information System (INIS)

Fujiwara, Asako; Nakano, Yoshiharu; Yaita, Tsuyoshi; Okuno, Kenji

2008-01-01

The tridentate ligand N,N'-dimethyl-N,N'-diphenylpyridine-2,6-dicarboxyamide (DMDPhPDA) and the corresponding lanthanum complex [La(NO 3 ) 3 (DMDPhPDA) 2 ] have been prepared and structurally characterised. The crystal structure of DMDPhPDA shows syn-anti conformation. In the lanthanum complex, two DMDPhPDA molecules coordinated to La(III) in a tridentate fashion and to three nitrate ions in a bidentate fashion make the lanthanum atom 12-coordinate. The crystal structure of [La(NO 3 ) 3 (DMDPhPDA) 2 ] has a C 2 symmetry. The stability constants determined by spectrophotometric titration suggest that [Ln(DMDPhPDA) 2 ] 3+ is the primary product in CH 3 CN solution and [Ln(DMDPhPDA) 3 ] 3+ is difficult to form. However, [Ln(DMDPhPDA) 2 ] 3+ could not be distinguished in 1 H NMR spectra. The 1 H NMR titration results imply that a fast ligand exchange process takes place

Results from colliding magnetized plasma jet experiments executed at the Trident laser facility

Science.gov (United States)

Manuel, M. J.-E.; Rasmus, A. M.; Kurnaz, C. C.; Klein, S. R.; Davis, J. S.; Drake, R. P.; Montgomery, D. S.; Hsu, S. C.; Adams, C. S.; Pollock, B. B.

2015-11-01

The interaction of high-velocity plasma flows in a background magnetic field has applications in pulsed-power and fusion schemes, as well as astrophysical environments, such as accretion systems and stellar mass ejections into the magnetosphere. Experiments recently executed at the Trident Laser Facility at the Los Alamos National Laboratory investigated the effects of an expanding aluminum plasma flow into a uniform 4.5-Tesla magnetic field created using a solenoid designed and manufactured at the University of Michigan. Opposing-target experiments demonstrate interesting collisional behavior between the two magnetized flows. Preliminary interferometry and Faraday rotation measurements will be presented and discussed. This work is funded by the U.S Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840. Support for this work was provided by NASA through Einstein Postdoctoral Fellowship grant number PF3-140111 awarded by the Chandra X-ray Center, which is operated by the Astrophysical Observatory for NASA under contract NAS8-03060.

Synthesis and characterization of 6,6’-bis(2-hydroxyphenyl)-2,2’-bipyridine ligand and its interaction with ct-DNA

Energy Technology Data Exchange (ETDEWEB)

Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor (Malaysia)

2015-09-25

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by {sup 1}H, 2D cosy and {sup 13}C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant K{sub b} = 1.19 × 10{sup 3} ± 0.08 M{sup −1}.

Histamine H3 receptor ligands in the group of (homo)piperazine derivatives.

Science.gov (United States)

Szczepanska, Katarzyna; Kuder, Kamil; Kiec-Kononowicz, Katarzyna

2017-11-23

Since its' discovery in 1983, followed by gene cloning in 1999, the histamine H3 receptor served as an outstanding target for drug discovery. The wide spectrum of possible therapeutic implications make H3R's one of the most researched areas in the vast GPCR ligands field - started from imidazole containing ligands, through various successful imidazole replacements, with recent introduction of Wakix® to pharmaceutical market. One of such replacements is piperazine moiety, a significant versatile scaffold in rational drug design for most of the GPCR ligands. Therefore, herein we review ligands built on piperazine, as well as its seven membered analogue azepine, that target H3R's and their potential therapeutical applications, in order to elucidate the current state of the art in this vast field. Due to a high level of structural divergence among compounds described herein, we decided to divide them into groups, where the key division element was the position of nitrogen basicity decreasing moieties in (homo)piperazine ring. Paying attention to a number of published structures and their overall high biological activity, one can realize that the (homo)piperazine scaffold bids a versatile template also for histamine H3 receptor ligands. With two possible substitution sites and therefore a number of possible structural combinations, piperazine derivatives stand as one of the largest group of high importance among H3R ligands. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 118; Issue 6. Utilization of LVO 2 − species (L2- is a tridentate ONS donor) as an inorganic analogue of carboxylate group: A journey to a new domain of coordination chemistry. Satyabrata Samanta Subodh Kanti Dutta Muktimoy Chaudhury. Volume 118 Issue 6 ...

Construction of a monoanionic S,N,S-pincer ligand with a pyrrole core by sequential [1,2] phospho-Fries rearrangement. Characterization of palladium and silver coordination complexes

NARCIS (Netherlands)

Fraix, A.; Lutz, M.; Spek, A.L.; Klein Gebbink, R.J.M.; van Koten, G.; Salaun, J. -Y; Jaffrès, P. -A

2010-01-01

The synthesis of an S,NH,S-pincer ligand possessing a pyrrole core and two O,O-diethylthiophosphonyl groups to design PS lateral coordination sites is reported. The synthetic procedure to produce this ligand makes use of the nitrogen atom of the pyrrole heterocycle to successively functionalize the

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the Caribbean Ocean in support of the Integrated Global Ocean Services System (IGOSS) project for 1971-01-28 (NODC Accession 7600706)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Synthesis of a new technetium radiotracer containing para-toluidine by tridentate chelation (N,N,O)

International Nuclear Information System (INIS)

Makhloufi, Amel

2011-01-01

Neuro degenerative diseases (Alzheimer, Parkinson, Creutzfeld-Jacob. and others) have an increasingly important impact as well on the economic plan as social. The diagnosis procedure and current therapies remain expensive and the assumption of responsibility of the patient is seldom assured. These last years, the development of new radiopharmaceuticals with aiming diagnosis procedure started again the interest for the search for new molecules. The asset of the synthesis of our technetium radiotracer, a tridentate chelate complex (N, N, O) resides in the facility of its obtaining; marking with the kit Alberto is done at a temperature about 90 degree approximately and this could consequently facilitate its implementation in the units of radiodiagnosis. Of lipophilic nature, neutral and of suitable molecular weight, the main challenge for this molecule would be to check its capacity to cross the blood-brain barrier by studying its cerebral extraction.

Donor, dad, or…? Young adults with lesbian parents' experiences with known donors.

Science.gov (United States)

Goldberg, Abbie E; Allen, Katherine R

2013-06-01

In this exploratory qualitative study of 11 young adults, ages 19-29 years, we examine how young people who were raised by lesbian parents make meaning out of and construct their relationships with known donors. In-depth interviews were conducted to examine how participants defined their family composition, how they perceived the role of their donors in their lives, and how they negotiated their relationships with their donors. Findings indicate that mothers typically chose known donors who were family friends, that the majority of participants always knew who their donors were, and that their contact with donors ranged from minimal to involved. Further, participants perceived their donors in one of three ways: as strictly donors and not members of their family; as extended family members but not as parents; and as fathers. The more limited role of donors in participants' construction of family relationships sheds light on how children raised in lesbian, gay, and bisexual families are contributing to the redefinition and reconstruction of complex kinship arrangements. Our findings hold implications for clinicians who work with lesbian-mother families, and suggest that young adulthood is an important developmental phase during which interest in and contact with the donor may shift, warranting a transfer of responsibility from mother to offspring in terms of managing the donor-child relationship. © FPI, Inc.

Manashi Panda

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Manashi Panda. Articles written in Journal of Chemical Sciences. Volume 119 Issue 1 January 2007 pp 3-9. Synthesis, structure, redox and spectra of green iridium complexes of tridentate azo-aromatic ligands · Manashi Panda Chayan Das Chen-Hsiung Hung Sreebrata ...

Iridium complexes containing mesoionic C donors: selective C(sp3)-H versus C(sp2)-H bond activation, reactivity towards acids and bases, and catalytic oxidation of silanes and water.

Science.gov (United States)

Petronilho, Ana; Woods, James A; Mueller-Bunz, Helge; Bernhard, Stefan; Albrecht, Martin

2014-11-24

Metalation of a C2-methylated pyridylimidazolium salt with [IrCp*Cl2]2 affords either an ylidic complex, resulting from C(sp(3))-H bond activation of the C2-bound CH3 group if the metalation is performed in the presence of a base, such as AgO2 or Na2CO3, or a mesoionic complex via cyclometalation and thermally induced heterocyclic C(sp(2))-H bond activation, if the reaction is performed in the absence of a base. Similar cyclometalation and complex formation via C(sp(2))-H bond activation is observed when the heterocyclic ligand precursor consists of the analogous pyridyltriazolium salt, that is, when the metal bonding at the C2 position is blocked by a nitrogen rather than a methyl substituent. Despite the strongly mesoionic character of both the imidazolylidene and the triazolylidene, the former reacts rapidly with D(+) and undergoes isotope exchange at the heterocyclic C5 position, whereas the triazolylidene ligand is stable and only undergoes H/D exchange under basic conditions, where the imidazolylidene is essentially unreactive. The high stability of the Ir-C bond in aqueous solution over a broad pH range was exploited in catalytic water oxidation and silane oxidation. The catalytic hydrosilylation of ketones proceeds with turnover frequencies as high as 6,000 h(-1) with both the imidazolylidene and the triazolylidene system, whereas water oxidation is enhanced by the stronger donor properties of the imidazol-4-ylidene ligands and is more than three times faster than with the triazolylidene analogue. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical bonding and electronic localization in a Ga(I) amide.

Science.gov (United States)

Thomsen, Maja K; Dange, Deepak; Jones, Cameron; Overgaard, Jacob

2015-10-05

The electron density in a one-coordinate [Ga(I) N(SiMe3 )R] complex has been determined from ab initio calculations and multipole modeling of 90 K X-ray data. The topologies of the Laplacian distribution and the ELI-D match a situation having an sp(3) -hybridized nitrogen with a tetrahedral arrangement of two single σ-bonds (to carbon and silicon) and two lone pairs pointing towards gallium in a scissor-grasping fashion. The analysis of the Laplacian distribution furthermore reveals a ligand-induced charge concentration (LICC) in the outer core of gallium oriented directly towards the nitrogen atom, and thus in between the two lone pairs. These observations might suggest that the trigonal planar nitrogen geometry result from a dative GaN bond, in which the roles of the metal and the ligand have been reversed with respect to a "standard" metal-ligand interaction, that is, the metal is here electron-donating. The ELI-D reveals a diffuse and directional lone pair on gallium, suggesting that this complex could serve as a σ-donor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Symmetry and structure of N-O shallow donor complexes in silicon

International Nuclear Information System (INIS)

Alt, H.Ch.; Wagner, H.E.

2012-01-01

Shallow donors in silicon related to nitrogen-oxygen complexes have been investigated by piezospectroscopy of their hydrogenic transitions in the far infrared. Complete stress dependences up to 0.25 GPa were obtained for the 1s→2p 0 and 1s→2p ± transitions of the most prominent members of the (N, O)-family, N-O-3 and N-O-5. Very unusual for shallow donors in silicon, the symmetry of the ground state wave function is T 2 -like. The lifting of orientational degeneracy for stress in the 〈1 0 0〉, 〈1 1 1〉, and 〈1 1 0〉 directions is compatible with a C 2v defect symmetry. Data from the other species of the (N, O)-family are indicative for the same symmetry. The microscopic structure of these centers, in part contradictory to present theoretical models, is discussed.

Synthesis of a Bis(thiophenolate)pyridine Ligand and Its Titanium, Zirconium, and Tantalum Complexes

KAUST Repository

Lenton, Taylor N.

2012-11-12

A precursor to a new tridentate LX 2 type ligand, bis(thiophenol)pyridine ((SNS)H 2 = (2-C 6H 4SH) 2-2,6-C 5H 3N), was prepared. Bis(thiophenolate)pyridine complexes of Ti, Zr, and Ta having dialkylamido coligands were synthesized and structurally characterized. The zirconium complex (SNS)Zr(NMe 2) 2 (4) displays C 2 symmetry in the solid state, unlike a related bis(phenolate)pyridine compound, C s-symmetric (ONO)Ti(NMe 2) 2. This change is likely the result of strain about the sulfur atom in the six-membered chelate with longer metal-sulfur and carbon-sulfur bonds. Solid-state structures of tantalum complexes (SNS)Ta(NMe 2) 3 (5) and (SNS)TaCl(NEt 2) 2 (6) also display pronounced C 2 twisting of the SNS ligand. 1D and 2D NMR experiments show that 5 is fluxional, with rotation about the Ta-N(amide) bonds occurring on the NMR time scale that interchange the equatorial amide methyl groups (ΔG ‡ 393 = 25.0(3) kcal/mol). The fluxional behavior of 6 in solution was also studied by variable-temperature 1H NMR. Observation of separate signals for the diastereotopic protons of the methylene unit of the diethylamide indicates that the complex remains locked on the NMR time scale in one diastereomeric conformation at temperatures below -50 °C, fast rotation about the equatorial amide Ta-N bonds occurs at higher temperature (ΔG ‡ 393 = 13.4(3) kcal/mol), and exchange of diastereomeric methylene protons occurs via inversion at Ta that interconverts antipodes (ΔG ‡ 393 ≈ 14(1) kcal/mol). © 2012 American Chemical Society.

Influence of the chelator structures on the stability of Re and Tc Tricarbonyl complexes: a computational study

International Nuclear Information System (INIS)

Hernández Valdés, Daniel; Rodríguez Riera, Zalua; Jáuregui Haza, Ulises; Díaz García, Alicia; Benoist, Eric

2016-01-01

The development of novel radiopharmaceuticals in nuclear medicine based on the M(CO)3 (M = Tc, Re) complexes has attracted great attention1. The versatility of this core and the easy production of the fac-[M(CO)3(H 2 O) 3 ]+ precursor could explain this interest2,3. The main characteristics of these tricarbonyl complexes are a high substitution stability of the three CO ligands and a corresponding lability of the coordinated water molecules, yielding, via easy exchange of a variety of mono-, bi-, and tridentate ligands, complexes of very high kinetic stability. A computational study of different tricarbonyl complexes for Re(I) and Tc(I) has been performed using density functional theory. The solvent effect was simulated using the polarizable continuum model. The fully optimized complexes show geometries that compare favorably with the X-ray data. These structures were used as a starting point to investigate the relative stability of tricarbonyl complexes with various tridentate ligands. They comprise an iminodiacetic acid unit for tridentate coordination to the fac-[M(CO) 3 ]+ moiety (M = Re, Tc), an aromatic ring system bearing a functional group (NO 2 -, NH 2 - and Cl-) as linking site model, and a tethering moiety (methylene, ethylene, propylene butylene or pentylene bridge) between the linking and coordinating sites. In general, Re complexes are more stables than the corresponding Tc complexes. Furthermore, the NH2 functional group, medium length in the carbon chain and meta substitution increase the stability of the complexes. The correlation of these results with the available experimental4 data on these systems allows bringing some understanding of the chemistry of tricarbonyl complexes. (author)

[Pr2(pdc3(Hpdc(H2O4]n·n(H3hp·8n(H2O, a One-Dimensional Coordination Polymer Containing PrO6N3 Tri-Capped Trigonal Prisms and PrO8N Mono-Capped Square Anti-Prisms (H2pdc = Pyridine 2,6-Dicarboxylic Acid, C7H5NO4; 3hp = 3-Hydroxy Pyridine, C5H5NO

Directory of Open Access Journals (Sweden)

Shahzad Sharif

2012-08-01

Full Text Available The synthesis, structure and some properties of the one-dimensional coordination polymer, [Pr2(pdc3(Hpdc]n·n(H3hp·8n(H2O, (H2pdc = pyridine 2,6-dicarboxylic acid, C7H5NO4; 3hp = 3-hydroxypyridine, C5H5NO are described. One of the Pr3+ ions is coordinated by two O,N,O-tridentate pdc2− ligands and one tridentate Hpdc− anion to generate a fairly regular PrO6N3 tri-capped trigonal prism, with the N atoms acting as the caps. The second Pr3+ ion is coordinated by one tridentate pdc2− dianion, four water molecules and two monodentate bridging pdc2− ligands to result in a PrO8N coordination polyhedron that approximates to a mono-capped square-anti-prism. The ligands bridge the metal-atom nodes into a chain, which extends in the [100] direction. The H3hp+ cation and uncoordinated water molecules occupy the inter-chain regions and an N–HLO and numerous O–HLO hydrogen bonds consolidate the structure. The H3hp+ species appears to intercalate between pendant pdc rings to consolidate the polymeric structure. Crystal data: 1 (C33H43N5O29Pr2, Mr = 1255.54, triclinic,  (No. 2, Z = 2, a = 13.2567(1 Å, b = 13.6304(2 Å, c = 13.6409(2 Å, α = 89.695(1°, β = 63.049(1°, γ = 86.105(1°, V = 2191.16(5 Å3, R(F = 0.033, wR(F2 = 0.084.

Benzannulated tris(2-mercapto-1-imidazolyl)hydroborato ligands: tetradentate κ4-S3H binding and access to monomeric monovalent thallium in an [S3] coordination environment.

Science.gov (United States)

Rong, Yi; Palmer, Joshua H; Parkin, Gerard

2014-01-21

The benzannulated tris(mercaptoimidazolyl)borohydride sodium complex, [Tm(Bu(t)Benz)]Na, has been synthesized via the reaction of NaBH4 with 1-tert-butyl-1,3-dihydro-2H-benzimidazole-2-thione, while [Tm(MeBenz)]K has been synthesized via the reaction of KBH4 with 1-methyl-1,3-dihydro-2H-benzimidazole-2-thione. The molecular structures of the solvated adducts, {[Tm(Bu(t)Benz)]Na(THF)}2(μ-THF)2 and [Tm(MeBenz)]K(OCMe2)3, have been determined by X-ray diffraction, which demonstrates that the [Tm(R)] ligands in these complexes adopt different coordination modes to that in {[Tm(MeBenz)]Na}2(μ-THF)3. Specifically, while the [Tm(MeBenz)] ligand of the sodium complex {[Tm(MeBenz)]Na}2(μ-THF)3 adopts a κ(3)-S3 coordination mode, the potassium complex [Tm(MeBenz)]K(OCMe2)3 adopts a most uncommon inverted κ(4)-S3H coordination mode in which the potassium binds to all three sulfur donors and the hydrogen of the B-H group in a linear KH-B manner. Furthermore, the [Tm(Bu(t)Benz)] ligand of {[Tm(Bu(t)Benz)]Na(THF)}2(μ-THF)2 adopts a κ(3)-S2H coordination mode, thereby demonstrating the flexibility of this ligand system. The monovalent thallium compounds, [Tm(MeBenz)]Tl and [Tm(Bu(t)Benz)]Tl, have been obtained via the corresponding reactions of [Tm(MeBenz)]Na and [Tm(Bu(t)Benz)]Na with TlOAc. X-ray diffraction demonstrates that the three sulfur donors of the [Tm(RBenz)] ligands of both [Tm(MeBenz)]Tl and [Tm(Bu(t)Benz)]Tl chelate to thallium. This coordination mode is in marked contrast to that in other [Tm(R)]Tl compounds, which exist as dinuclear molecules wherein two of the sulfur donors coordinate to different thallium centers. As such, this observation provides further evidence that benzannulation promotes κ(3)-S3 coordination in this system.

Laparoscopic donor nephrectomy

Directory of Open Access Journals (Sweden)

Gupta Nitin

2005-01-01

Full Text Available Of the various options for patients with end stage renal disease, kidney transplantation is the treatment of choice for a suitable patient. The kidney for transplantation is retrieved from either a cadaver or a live donor. Living donor nephrectomy has been developed as a method to address the shortfall in cadaveric kidneys available for transplantation. Laparoscopic living donor nephrectomy (LLDN, by reducing postoperative pain, shortening convalescence, and improving the cosmetic outcome of the donor nephrectomy, has shown the potential to increase the number of living kidney donations further by removing some of the disincentives inherent to donation itself. The technique of LLDN has undergone evolution at different transplant centers and many modifications have been done to improve donor safety and recipient outcome. Virtually all donors eligible for an open surgical procedure may also undergo the laparoscopic operation. Various earlier contraindications to LDN, such as right donor kidney, multiple vessels, anomalous vasculature and obesity have been overcome with increasing experience. Laparoscopic live donor nephrectomy can be done transperitoneally or retroperitoneally on either side. The approach is most commonly transperitoneal, which allows adequate working space and easy dissection. A review of literature and our experience with regards to standard approach and the modifications is presented including a cost saving model for the developing countries. An assessment has been made, of the impact of LDN on the outcome of donor and the recipient.

Crosstalk between complement and Toll-like receptor activation in relation to donor brain death and renal ischemia-reperfusion injury.

Science.gov (United States)

Damman, Jeffrey; Daha, Mohamed R; van Son, Willem J; Leuvenink, Henri G; Ploeg, Rutger J; Seelen, Marc A

2011-04-01

Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen activated protein kinases (MAPKs) might be the key molecules linking both the complement and TLR pathways together. Complement and TLRs are important mediators of renal ischemia-reperfusion injury (IRI). Besides IRI, complement C3 can also be upregulated and activated in the kidney before transplantation as a direct result of brain death (BD) in the donor. This local upregulation and activation of complement in the donor kidney has been proven to be detrimental for renal allograft outcome. Also TLR4 and several of its major ligands are upregulated by donor BD compared to living donors. Important and in line with the observations above, kidney transplant recipients have a benefit when receiving a kidney from a TLR4 Asp299Gly/Thr399Ile genotypic donor. The role of complement and TLRs and crosstalk between these two innate immune systems in relation to renal injury during donor BD and ischemia-reperfusion are focus of this review. Future strategies to target complement and TLR activation in kidney transplantation are considered. ©2011 The Authors Journal compilation©2011 The American Society of Transplantation and the American Society of Transplant Surgeons.

Synthesis, characterization and thermal study of some transition metal complexes of an asymmetrical tetradentate Schiff base ligand

Directory of Open Access Journals (Sweden)

ACHUT S. MUNDE

2010-03-01

Full Text Available Complexes of Cu(II, Ni(II, Co(II, Mn(II and Fe(III with an asymmetric tetradentate Schiff base ligand derived from dehydroacetic acid, 4-methyl-o-phenylenediamine and salicylic aldehyde were synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV–Vis, IR, 1H-NMR spectroscopy, X-ray diffraction analysis of powdered samples and thermal analysis, and screened for antimicrobial activity. The IR spectral data suggested that the ligand behaves as a dibasic tetadentate ligand towards the central metal ion with an ONNO donor atoms sequence. From the microanalytical data, the stoichiometry of the complexes 1:1 (metal:ligand was found. The physico-chemical data suggested square planar geometry for the Cu(II and Ni(II complexes and octahedral geometry for the Co(II, Mn(II and Fe(III complexes. The thermal behaviour (TGA/DTA of the complexes was studied and kinetic parameters were determined by Horowitz–Metzger and Coats–Redfern methods. The powder X-ray diffraction data suggested a monoclinic crystal system for the Co(II, Mn(II and Fe(III complexes. The ligand and their metal complexes were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli and fungicidal activity against Aspergillus niger and Trichoderma viride.

Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

International Nuclear Information System (INIS)

Zhao Jing; Liang Jingjing; Pan Yingli; Zhang Yong; Jia Dingxian

2011-01-01

Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en) 2 (dien)(η 2 -SbSe 4 )] (Ln=Ce(1a), Nd(1b)), [Ln(en) 2 (dien)(SbSe 4 )] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)(μ-η 1 ,η 2 -SbSe 4 )] ∞ (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)(η 2 -SbSe 4 )] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe 4 ] 3- acts as a monodentate ligand mono-SbSe 4 , a bidentate chelating ligand η 2 -SbSe 4 or a tridentate bridging ligand μ-η 1 ,η 2 -SbSe 4 to the lanthanide(III) center depending on the Ln 3+ ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E g between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: → Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. → The [SbSe 4 ] 3- anion acts as a mono-SbSe 4 , a η 2 -SbSe 4 or a μ-η 1 ,η 2 -SbSe 4 ligand to the Ln 3+ ions. → The soft base ligand [SbSe 4 ] 3- can be controlled to coordinate to the Ln 3+ ions with en+dien and en+trien as co-ligands.

Self-assembly in lanthanum(III) and calcium(II) complexes of salicylaldimines derived from putrescine

International Nuclear Information System (INIS)

Pospieszna-Markiewicz, Izabela; Kaczmarek, Malgorzata T.; Kubicki, Maciej; Radecka-Paryzek, Wanda

2008-01-01

The one-step template reaction of salicylaldehyde with putrescine, a biogenic diamine, in the presence of lanthanum(III) or calcium(II) ions produces salicylaldimine complexes containing the N,N'-bis(salicylidene)-1,4-butanediamine ligand L as a result of the [2 + 1] Schiff base condensation. The X-ray diffraction studies of the lanthanum complex reveals an infinite [La 2 L 4 (NO 3 ) 6 ] ∞ polymeric structure based on networks of 10-coordinated La(III) nodes linked by bridging unionized ligands that use exclusively the oxygens as donor atoms with the nitrogen atoms not being involved in coordination

Formation of adduct of cerium (4) thenoyltrifluoroacetonate

International Nuclear Information System (INIS)

Anyfrieva, S.I.; Polyakova, G.V.; Snezhko, N.I.; Pechurova, N.I.; Martynenko, L.I.; Spitsyn, V.I.

1981-01-01

Adduct formation of thenoyltrifluoroacetonate of Ce(4) [Ce(TTFA) 4 ] with seven nitrogen- and oxygen-containing donor additional ligands is studied using the methods of IR-spectroscopy, derivatography, X-ray phase analysis. The presence of formation of Ce(TTFA) 4 adducts with phosphorus-containing additional ligands tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), triphenylphosphine oxide (TPPO); α, α'-dipyridyl (Dipy) and o-phenanthroline (Phen) is established. The adduct Ce(TTFA) 4 stable to reduction is formed with Dipy, and in the case of Phen, TBP, TOPO, TPPO in the process of adduct formation the reduction of Ce(4) to Ce(3) takes place [ru

Synthesis, spectral characterization and structural studies of a novel O, N, O donor semicarbazone and its binuclear copper complex with hydrogen bond stabilized lattice

Science.gov (United States)

Layana, S. R.; Saritha, S. R.; Anitha, L.; Sithambaresan, M.; Sudarsanakumar, M. R.; Suma, S.

2018-04-01

A novel O,N,O donor salicylaldehyde-N4-phenylsemicarbazone, (H2L) has been synthesized and physicochemically characterized. Detailed structural studies of H2L using single crystal X-ray diffraction technique reveals the existence of intra and inter molecular hydrogen bonding interactions, which provide extra stability to the molecule. We have successfully synthesized a binuclear copper(II) complex, [Cu2(HL)2(NO3)(H2O)2]NO3 with phenoxy bridging between the two copper centers. The complex was characterized by elemental analysis, magnetic susceptibility and conductivity measurements, FT-IR, UV-Visible, mass and EPR spectral methods. The grown crystals of the copper complex were employed for the single crystal X-ray diffraction studies. The complex possesses geometrically different metal centers, in which the ligand coordinates through ketoamide oxygen, azomethine nitrogen and deprotonated phenoxy oxygen. The extensive intermolecular hydrogen bonding interactions of the coordinated and the lattice nitrate groups interconnect the complex units to form a 2D supramolecular assembly. The ESI mass spectrum substantiates the existence of 1:1 complex. The g values obtained from the EPR spectrum in frozen DMF suggest dx2 -y2 ground state for the unpaired electron.

Monitoring ligand-dependent assembly of receptor ternary complexes in live cells by BRETFect.

Science.gov (United States)

Cotnoir-White, David; El Ezzy, Mohamed; Boulay, Pierre-Luc; Rozendaal, Marieke; Bouvier, Michel; Gagnon, Etienne; Mader, Sylvie

2018-03-13

There is currently an unmet need for versatile techniques to monitor the assembly and dynamics of ternary complexes in live cells. Here we describe bioluminescence resonance energy transfer with fluorescence enhancement by combined transfer (BRETFect), a high-throughput technique that enables robust spectrometric detection of ternary protein complexes based on increased energy transfer from a luciferase to a fluorescent acceptor in the presence of a fluorescent intermediate. Its unique donor-intermediate-acceptor relay system is designed so that the acceptor can receive energy either directly from the donor or indirectly via the intermediate in a combined transfer, taking advantage of the entire luciferase emission spectrum. BRETFect was used to study the ligand-dependent cofactor interaction properties of the estrogen receptors ERα and ERβ, which form homo- or heterodimers whose distinctive regulatory properties are difficult to dissect using traditional methods. BRETFect uncovered the relative capacities of hetero- vs. homodimers to recruit receptor-specific cofactors and regulatory proteins, and to interact with common cofactors in the presence of receptor-specific ligands. BRETFect was also used to follow the assembly of ternary complexes between the V2R vasopressin receptor and two different intracellular effectors, illustrating its use for dissection of ternary protein-protein interactions engaged by G protein-coupled receptors. Our results indicate that BRETFect represents a powerful and versatile technique to monitor the dynamics of ternary interactions within multimeric complexes in live cells.

Marginal kidney donor

Directory of Open Access Journals (Sweden)

Ganesh Gopalakrishnan

2007-01-01

Full Text Available Renal transplantation is the treatment of choice for a medically eligible patient with end stage renal disease. The number of renal transplants has increased rapidly over the last two decades. However, the demand for organs has increased even more. This disparity between the availability of organs and waitlisted patients for transplants has forced many transplant centers across the world to use marginal kidneys and donors. We performed a Medline search to establish the current status of marginal kidney donors in the world. Transplant programs using marginal deceased renal grafts is well established. The focus is now on efforts to improve their results. Utilization of non-heart-beating donors is still in a plateau phase and comprises a minor percentage of deceased donations. The main concern is primary non-function of the renal graft apart from legal and ethical issues. Transplants with living donors outnumbered cadaveric transplants at many centers in the last decade. There has been an increased use of marginal living kidney donors with some acceptable medical risks. Our primary concern is the safety of the living donor. There is not enough scientific data available to quantify the risks involved for such donation. The definition of marginal living donor is still not clear and there are no uniform recommendations. The decision must be tailored to each donor who in turn should be actively involved at all levels of the decision-making process. In the current circumstances, our responsibility is very crucial in making decisions for either accepting or rejecting a marginal living donor.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 119; Issue 1. Issue front cover thumbnail. Volume 119, Issue 1. January 2007, pages 3-51. pp 3-9. Synthesis, structure, redox and spectra of green iridium complexes of tridentate azo-aromatic ligands · Manashi Panda Chayan Das Chen-Hsiung Hung Sreebrata ...

Bulletin of the Chemical Society of Ethiopia - Vol 21, No 1 (2007)

African Journals Online (AJOL)

Synthesis and crystal structure of an oxorhenium(V) complex containing a tridentate imidazole ligand · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Zenixole R. Tshentu, Thomas I.A. Gerber, Peter Mayer. http://dx.doi.org/10.4314/bcse.v21i1.61373 ...

Fulltext PDF

Indian Academy of Sciences (India)

Administrator

Tridentate Schiff bases are excellent ligands in forming dinuclear complexes of metal ions which prefer square-planar geometry. Deprotonated monobasic arylhydrazones of 2- pyridine-carboxaldehyde can coordinate a metal ion via the pyridine-N, the imine-N and the amide-O atoms. We are interested in amide-O bridged ...

Benzannulated Tris(2-mercapto-1-imidazolyl)hydroborato Ligands: Tetradentate κ4–S3H Binding and Access to Monomeric Monovalent Thallium in an [S3] Coordination Environment

Science.gov (United States)

Rong, Yi; Palmer, Joshua H.; Parkin, Gerard

2013-01-01

The benzannulated tris(mercaptoimidazolyl)borohydride sodium complex, [TmButBenz]Na, has been synthesized via the reaction of NaBH4 with 1-tert-butyl-1,3-dihydro-2H-benzimidazole-2-thione, while [TmMeBenz]K has been synthesized via the reaction of KBH4 with 1-methyl-1,3-dihydro-2H-benzimidazole-2-thione. The molecular structures of the solvated adducts, {[TmButBenz]Na(THF)}2(μ-THF)2 and [TmMeBenz]K(OCMe2)3, have been determined by X-ray diffraction, which demonstrates that the [TmR] ligands in these complexes adopt different coordination modes to that in {[TmMeBenz]Na}2(μ-THF)3. Specifically, while the [TmMeBenz] ligand of the sodium complex {[TmMeBenz]Na}2(μ-THF)3 adopts a κ3-S3 coordination mode, the potassium complex [TmMeBenz]K(OCMe2)3 adopts a most uncommon inverted κ4-S3H coordination mode in which the potassium binds to all three sulfur donors and the hydrogen of the B–H group in a linear K•••H–B manner. Furthermore, the [TmButBenz] ligand of {[TmButBenz]Na(THF)}2(μ-THF)2 adopts a κ3-S2H coordination mode, thereby demonstrating the flexibility of this ligand system. The monovalent thallium compounds, [TmMeBenz]Tl and [TmButBenz]Tl, have been obtained via the corresponding reactions of [TmMeBenz]Na and [TmButBenz]Na with TlOAc. X-ray diffraction demonstrates that the three sulfur donors of the [TmRBenz] ligands of both [TmMeBenz]Tl and [TmButBenz]Tl chelate to thallium. This coordination mode is in marked contrast to that in other [TmR]Tl compounds, which exist as dinuclear molecules wherein two of the sulfur donors coordinate to different thallium centers. As such, this observation provides further evidence that benzannulation promotes κ3-S3 coordination in this system. PMID:24201311

Two New Three-Dimensional Pillared-Layer Co(II and Cu(II Frameworks Involving a [M2(EO-N32] Motif from a Semi-Flexible N-Donor Ligand, 5,5′-Bipyrimidin: Syntheses, Structures and Magnetic Properties

Directory of Open Access Journals (Sweden)

Zu-Zhen Zhang

2018-02-01

Full Text Available Two new three-dimensional (3D Co(II- and Cu(II-azido frameworks, [Co2(N34(bpym2]n (1 and [Cu2(N34(bpym]n (2, were successfully synthesized by introducing a semi-flexible N-donor ligand, 5,5′-bipyrimidin (bpym, with different bridging modes and orientations. Compounds 1 and 2 were structurally characterized by X-ray crystallography, IR spectroscopy, thermogravimetry and elemental analysis. Compounds 1 and 2 are 3D pillared-layer frameworks with double end-on (EO azido bridged dinuclear motifs, [M2(EO-N32]. In Compound 1, the bpym ligands show trans μ2-bridging mode and the role as pillars to connect the Co(II-azido layers, composed of [Co2(EO-N32] motifs and single end-to-end (EE azido bridges, to a 3D network with BN topology. In contrast, in 2, the bpym ligand adopts a twisted μ4-bridging mode, which not only connects the adjacent [Cu2(EO-N32] units to a layer, but also functions as a pillar for the layers of the 3D structure. The structural diversities between the two types of architectures can be attributed to the coordination geometry preference of the metal ions (octahedral for Co2+ and square pyramidal for Cu2+. Magnetic investigations revealed that Compound 1 exhibits ferromagnetic-like magnetic ordering due to spin canting with a critical temperature, TC = 33.0 K, and furthers the field-induced magnetic transitions of metamagnetism at temperatures below TC. Compound 2 shows an antiferromagnetic ordering with TN = 3.05 K and a field-induced magnetic transition of spin-flop at temperatures below the TN.

Donor Retention in Online Crowdfunding Communities: A Case Study of DonorsChoose.org.

Science.gov (United States)

Althoff, Tim; Leskovec, Jure

2015-05-01

Online crowdfunding platforms like DonorsChoose.org and Kick-starter allow specific projects to get funded by targeted contributions from a large number of people. Critical for the success of crowdfunding communities is recruitment and continued engagement of donors. With donor attrition rates above 70%, a significant challenge for online crowdfunding platforms as well as traditional offline non-profit organizations is the problem of donor retention. We present a large-scale study of millions of donors and donations on DonorsChoose.org, a crowdfunding platform for education projects. Studying an online crowdfunding platform allows for an unprecedented detailed view of how people direct their donations. We explore various factors impacting donor retention which allows us to identify different groups of donors and quantify their propensity to return for subsequent donations. We find that donors are more likely to return if they had a positive interaction with the receiver of the donation. We also show that this includes appropriate and timely recognition of their support as well as detailed communication of their impact. Finally, we discuss how our findings could inform steps to improve donor retention in crowdfunding communities and non-profit organizations.

The use of halloysite functionalized with isothiouronium salts as an organic/inorganic hybrid adsorbent for uranium(VI) ions removal.

Science.gov (United States)

Gładysz-Płaska, A; Majdan, M; Tarasiuk, B; Sternik, D; Grabias, E

2018-07-15

Elimination of U(VI) from nuclear wastes and from the underground water near the uranium mines is the serious problem. Therefore search for new sorbents for U(VI) is still a big challenge for the scientists. This paper investigates of U(VI) ions sorption on halloysite modified with the isothiouronium salts: S-dodecaneisothiouronium bromide (ligand 1), S,S'-dodecane-1,12-diylbis(isothiouronium bromide) (ligand 2), S-hexadecaneisothiouronium chloride (ligand 3), S,S'-naphthalene-1,4-diylbis(methylisothiouronium) dichloride (ligand 4), and S,S'-2,5-dimethylbenzene-1,4-diylbis(methylisothiouronium) dichloride (ligand 5). It was established that halloysite modified by the ligands with four nitrogen atoms in their structure (ligand-5, 2 and 4) was characterized by higher sorption capacity compared with that modified by the ligands with two donor nitrogens (ligand-1 and 3). The maximum sorption capacity of halloysite-5 toward U(VI) was 157 mg U/g and this places the modified mineral among the most effective sorbents for U(VI) removal from wastes. As follows from ATR, XPS and thermal degradation spectra of the sorption products [R-S-C(NH)(NH 2 )] n = 1-2 (UO 2 2+ ) complexes are formed on the external surface of the halloysite whereas oligomeric hydroxy complexes (UO 2 ) 3 (OH) 5 + and (UO 2 ) 4 (OH) 7 + are present in the interior of halloysite structure and interact predominantly with aluminols. Copyright © 2018 Elsevier B.V. All rights reserved.

Temperature profiles from expendable bathythermograph (XBT) casts from the TRIDENT in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) from 1972-12-15 to 1972-12-20 (NODC Accession 7600705)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the TRIDENT in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the the University of Rhode...

Synthesis, photo-, and electrochemistry of ruthenium bis(bipyridine) complexes comprising a N-heterocyclic carbene ligand.

Science.gov (United States)

Leigh, Vivienne; Ghattas, Wadih; Lalrempuia, Ralte; Müller-Bunz, Helge; Pryce, Mary T; Albrecht, Martin

2013-05-06

Analogues of [Ru(bpy)3](2+) were prepared in which one pyridine ligand site is substituted by a N-heterocyclic carbene (NHC) ligand, that is, either by an imidazolylidene with a variable wingtip group R (R = Me, 3a; R = Et, 3b; R = iPr, 3c), or by a benzimidazolylidene (Me wingtip group, 3d), or by a 1,2,3-triazolylidene (Me wingtip group, 3e). All complexes were characterized spectroscopically, photophysically, and electrochemically. An increase of the size of the wingtip groups from Me to Et or iPr groups distorts the octahedral geometry (NMR spectroscopy) and curtails the reversibility of the ruthenium oxidation. NHC ligands with methyl wingtip groups display reversible ruthenium oxidation at a potential that reflects the donor properties of the NHC ligand (triazolylidene > imidazolylidene > benzimidazolylidene). The most attractive properties were measured for the triazolylidene ruthenium complex 3e, featuring the smallest gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the series (2.41 eV), a slightly red-shifted absorption profile, and reasonable excited-state lifetime (188 ns) when compared to [Ru(bpy)3](2+). These features demonstrate the potential utility of triazolylidene ruthenium complexes as photosensitizers for solar energy conversion.

The role of missing killer cell immunoglobulin-like receptor ligands in T cell replete peripheral blood stem cell transplantation from HLA-identical siblings.

Science.gov (United States)

Clausen, Johannes; Kircher, Brigitte; Auberger, Jutta; Schumacher, Petra; Ulmer, Hanno; Hetzenauer, Gabriele; Wolf, Dominik; Gastl, Günther; Nachbaur, David

2010-02-01

The contribution of natural killer (NK) cells to graft-versus-malignancy (GVM) effects following hematopoietic stem cell transplantation (HSCT) remains uncertain, particularly in the HLA-identical setting. A model considering missing HLA ligands to the donor's inhibitory killer cell immunoglobulin-like receptor (KIR), termed the missing KIR ligand model, has been established in T cell depleted bone marrow transplantation (BMT), but lacks validity in other cohorts with different treatment characteristics. We hypothesized that the impact of missing KIR ligands on relapse-free survival (RFS) and overall survival (OS) in T cell replete peripheral blood SCT (PBSCT) differs from that in the T cell depleted BMT setting, and retrospectively evaluated 100 consecutive, HLA-identical sibling transplantations for hematologic malignancies. In addition to KIR ligand status, we considered the donors' activating KIRs and grafted NK, T, and CD34(+) cell doses. Our findings demonstrate noninferiority for OS (P = .005) and RFS (P = .002) for the heterozygous HLA-C group KIR ligand status (C1/2; n = 47) compared with patients missing either C1 or C2 (n = 53). Similarly, OS (P = .031) and RFS (P = .034) of Bw4-positive patients was noninferior to that of patients missing a Bw4 ligand to KIR3DL1. By multivariate analysis, C1/2 heterozygous patients had a favorable risk ratio (RR) for relapse (RR = 0.28; P = .003), RFS (RR = 0.56; P = .046), and acute graft-versus-host disease grade II-IV (RR = 0.36; P = .05). Following reduced-intensity conditioning (RIC), but not standard-intensity conditioning, myeloablative (MA) transplantation, a grafted NK cell dose above the median (3.4 x 10(7)/kg) was associated with a lower risk of relapse (RR = 0.57; P = .003) and improved survival (RR = 0.78; P = .03). Overall, our findings support a role for NK alloreactivity in HLA-identical HSCT, but argue against a favorable impact of missing KIR ligands in the given setting. We conclude that the mechanism

Thorium(IV) and zirconium(IV) complexes of oxygen donor ligands. Pt. 12

International Nuclear Information System (INIS)

Agarwal, R.K.; Jain, P.C.; Kapur, V.; Sharma, S.; Srivastava, A.K.

1980-01-01

Crystalline thorium (IV) chelates with mono N-oxides of 2,2'-bipyridine (bipyNO) and 1,10-phenanthroline (phenNO), ThX 4 x 2L(X = Cl,Br,NO 3 or NCS) and ThX 4 x 3L(X = I or ClO 4 and L = bipyNO or phenNO) have been synthesised and characterized on the basis of i.r. spectra, molar conductance, molecular weights, t.g.a. and d.t.a. data. All the complexes are weakly diamagnetic and contain bipyNO and phenNO bonded to thorium(IV) through nitrogen and oxygen. The coordination number of thorium(IV) varies from six to twelve depending on the nature of the anions. (orig.) [de

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the East Coast - US/Canada in support of the Integrated Global Ocean Services System (IGOSS) project for 1969-07-10 (NODC Accession 7600701)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Trithiocyanurate Complexes of Iron, Manganese and Nickel and Their Anticholinesterase Activity

Directory of Open Access Journals (Sweden)

Pavel Kopel

2014-04-01

Full Text Available The complexes of Fe(II, Mn(II and Ni(II with a combination of a Schiff base, nitrogen-donor ligand or macrocyclic ligand and trithiocyanuric acid (ttcH3 were prepared and characterized by elemental analysis and spectroscopies. Crystal and molecular structures of the iron complex of composition [Fe(L1](ttcH2(ClO4·EtOH·H2O (1, where L1 is Schiff base derived from tris(2-aminoethylamine and 2-pyridinecarboxaldehyde, were solved. It was found that the Schiff base is coordinated to the central iron atom by six nitrogens forming deformed octahedral arrangement, whereas trithiocyanurate(1- anion, perchlorate and solvent molecules are not coordinated. The X-ray structure of the Schiff base sodium salt is also presented and compared with the iron complex. The anticholinesterase activity of the complexes was also studied.

Nyretransplantation med levende donor

DEFF Research Database (Denmark)

Kamper, A L; Løkkegaard, H; Rasmussen, F

2000-01-01

In recent years transplantation from living donors has accounted for 25-30% of all kidney transplants in Denmark corresponding to 40-45 per year. Most of these living donors are parents or siblings, although internationally an increasing number are unrelated donors. Donor nephrectomy is associate...... in cadaver transplantation. The ethical and psychological aspects related to transplantation from a living donor are complex and need to be carefully evaluated when this treatment is offered to the patients....

Adducts of nitrogenous ligands with rhodium(II) tetracarboxylates and tetraformamidinate: NMR spectroscopy and density functional theory calculations.

Science.gov (United States)

Cmoch, Piotr; Głaszczka, Rafał; Jaźwiński, Jarosław; Kamieński, Bohdan; Senkara, Elżbieta

2014-03-01

Complexation of tetrakis(μ2-N,N'-diphenylformamidinato-N,N')-di-rhodium(II) with ligands containing nitrile, isonitrile, amine, hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups has been studied in liquid and solid phases using (1)H, (13)C and (15)N NMR, (13)C and (15)N cross polarisation-magic angle spinning NMR, and absorption spectroscopy in the visible range. The complexation was monitored using various NMR physicochemical parameters, such as chemical shifts, longitudinal relaxation times T1 , and NOE enhancements. Rhodium(II) tetraformamidinate selectively bonded only unbranched amine (propan-1-amine), pentanenitrile, and (1-isocyanoethyl)benzene. No complexation occurred in the case of ligands having hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups, and more expanded amine molecules such as butan-2-amine and 1-azabicyclo[2.2.2]octane. Such features were opposite to those observed in rhodium(II) tetracarboxylates, forming adducts with all kind of ligands. Special attention was focused on the analysis of Δδ parameters, defined as a chemical shift difference between signal in adduct and corresponding signal in free ligand. In the case of (1)H NMR, Δδ values were either negative in adducts of rhodium(II) tetraformamidinate or positive in adducts of rhodium(II) tetracarboxylates. Experimental findings were supported by density functional theory molecular modelling and gauge independent atomic orbitals chemical shift calculations. The calculation of chemical shifts combined with scaling procedure allowed to reproduce qualitatively Δδ parameters. Copyright © 2013 John Wiley & Sons, Ltd.

SELLING, DELIVERY AND TRADE MARKETING – AN OPERATIONAL TRIDENT OF THE DISTRIBUTION SYSTEM

Directory of Open Access Journals (Sweden)

Ioana Olariu

2013-12-01

Full Text Available This paper highlights the way in which a distribution system can be made operational in FMCG, starting from the interaction between three components of the system: selling, delivery and trade marketing. On this basis, I have categorized the improvement opportunities of each component, using the appropriate key performance indicators (KPIs of the system objectives. The optimal configuration of instruments and successful interaction of these components, improve the distribution system contribution to company performance. A specific system, defined for solving marketing problems, must be designed according to this purpose, and in this regard, all the significant elements and relationships must be subordinate to the objective by which it will achieve the desired solution. Business objectives achievement can be measured as effectiveness - the degree to which objectives were achieved, or as efficiency - the degree to which objectives have been achieved in the available resources. For evaluating the effectiveness with which an operative marketing system turns its sources into necessary results to solve a problem, it requires certain criteria to measure performance. These three elements: selling, delivery and trade marketing, are a trident of distribution which can lead to an optimal approach of market opportunities.

TRIDENT: a two-dimensional, multigroup, triangular mesh discrete ordinates, explicit neutron transport code

International Nuclear Information System (INIS)

Seed, T.J.; Miller, W.F. Jr.; Brinkley, F.W. Jr.

1977-03-01

TRIDENT solves the two-dimensional-multigroup-transport equations in rectangular (x-y) and cylindrical (r-z) geometries using a regular triangular mesh. Regular and adjoint, inhomogeneous and homogeneous (k/sub eff/ and eigenvalue searches) problems subject to vacuum, reflective, white, or source boundary conditions are solved. General anisotropic scattering is allowed and anisotropic-distributed sources are permitted. The discrete-ordinates approximation is used for the neutron directional variables. An option is included to append a fictitious source to the discrete-ordinates equations that is defined such that spherical-harmonics solutions (in x-y geometry) or spherical-harmonics-like solutions (in r-z geometry) are obtained. A spatial-finite-element method is used in which the angular flux is expressed as a linear polynomial in each triangle that is discontinous at triangle boundaries. Unusual Features of the program: Provision is made for creation of standard interface output files for S/sub N/ constants, angle-integrated (scalar) fluxes, and angular fluxes. Standard interface input files for S/sub N/ constants, inhomogeneous sources, cross sections, and the scalar flux may be read. Flexible edit options as well as a dump and restart capability are provided

Chemical Annealing of Zinc Tetraphenylporphyrin Films: Effects on Film Morphology and Organic Photovoltaic Performance

KAUST Repository

Trinh, Cong

2012-07-10

We present a chemical annealing process for organic thin films. In this process, a thin film of a molecular material, such as zinc tetraphenylporphyrin (ZnTPP), is exposed to a vapor of nitrogen-based ligand (e.g., pyrazine, pz, and triazine, tz), forming a film composed of the metal-ligand complex. Fast and quantitative formation of the complex leads to marked changes in the morphology and optical properties of the film. X-ray diffraction studies show that the chemical annealing process converts amorphous ZnTPP films to crystalline ZnTPP•ligand films, whose porphryin planes lie nearly parallel to the substrate (average deviation is 8° for the ZnTPP•pz film). Organic solar cells were prepared with ZnTPP donor and C 60 acceptor layers. Devices were prepared with and without chemical annealing of the ZnTPP layer with a pyrazine ligand. The devices with chemically annealed ZnTPP donor layer show an increase in short-circuit current (J SC) and fill factor (FF) relative to analogous unannealed devices, presumably because of enhanced exciton diffusion length and improved charge conductivity. The open circuit voltages (V OC) of the chemically annealed devices are lower than their unannealed counterpart because of enhanced polaron pair recombination at the donor/acceptor heterojunction. A net improvement of 5-20% in efficiency has been achieved, after chemical annealing of ZnTPP films with pyrazine. © 2012 American Chemical Society.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

All the complexes displayed large number of redox responses. A brief mention about the future projection of this work is noted. Volume 119 Issue 1 January 2007 pp 3-9. Synthesis, structure, redox and spectra of green iridium complexes of tridentate azo-aromatic ligands · Manashi Panda Chayan Das Chen-Hsiung Hung ...

Investigation of the Copper Binding Site And the Role of Histidine As a Ligand in Riboflavin Binding Protein

Energy Technology Data Exchange (ETDEWEB)

Smith, S.R.; Bencze, K.Z.; Russ, K.A.; Wasiukanis, K.; Benore-Parsons, M.; Stemmler, T.L.

2009-05-26

Riboflavin Binding Protein (RBP) binds copper in a 1:1 molar ratio, forming a distinct well-ordered type II site. The nature of this site has been examined using X-ray absorption and pulsed electron paramagnetic resonance (EPR) spectroscopies, revealing a four coordinate oxygen/nitrogen rich environment. On the basis of analysis of the Cambridge Structural Database, the average protein bound copper-ligand bond length of 1.96 {angstrom}, obtained by extended x-ray absorption fine structure (EXAFS), is consistent with four coordinate Cu(I) and Cu(II) models that utilize mixed oxygen and nitrogen ligand distributions. These data suggest a Cu-O{sub 3}N coordination state for copper bound to RBP. While pulsed EPR studies including hyperfine sublevel correlation spectroscopy and electron nuclear double resonance show clear spectroscopic evidence for a histidine bound to the copper, inclusion of a histidine in the EXAFS simulation did not lead to any significant improvement in the fit.

New twists and turns for actinide chemistry: organometallic infinite coordination polymers of thorium diazide

Energy Technology Data Exchange (ETDEWEB)

Monreal, Marisa J.; Seaman, Lani A.; Goff, George S.; Michalczyk, Ryszard; Morris, David E.; Scott, Brian L.; Kiplinger, Jaqueline L. [Los Alamos National Laboratory, Los Alamos, NM (United States)

2016-03-07

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Influence of kinship on donors' mental burden in living donor liver transplantation.

Science.gov (United States)

Erim, Yesim; Beckmann, Mingo; Kroencke, Sylvia; Sotiropoulos, Georgios C; Paul, Andreas; Senf, Wolfgang; Schulz, Karl-Heinz

2012-08-01

In the context of living donor liver transplantation (LDLT), German transplantation law stipulates that donor candidates should primarily be relatives of the recipients or persons with distinct and close relationships. In this study, we investigated the influence of the relationship between the donor and the recipient on the donor's emotional strain before transplantation. Donors were categorized according to the following subgroups: (1) parents donating for their children, (2) children donating for their parents, (3) siblings, (4) spouses, (5) other relatives, and (6) nonrelatives. The sample consisted of 168 donor candidates. Anxiety (F = 2.8, P = 0.02), depression (F = 2.6, P = 0.03), and emotional quality of life (F = 3.1, P = 0.01) differed significantly according to the relationship between the donor and the recipient. In comparison with healthy controls, parents donating for their children were significantly less stressed before LDLT and demonstrated fewer anxiety (P depression symptoms (P < 0.05). Adult children donating for their parents demonstrated the highest mental burden and the lowest emotional quality of life. However, this was not due to the responsibility of these children for their own families because differences between donors with children and donors without children could not be ascertained. This group should be given special attention before LDLT and during follow-up visits, and psychological help should be provided when it is necessary. Copyright © 2012 American Association for the Study of Liver Diseases.

Synthesis, structure, DNA/BSA binding and antibacterial studies of NNO tridentate Schiff base metal complexes

Science.gov (United States)

Sakthi, Marimuthu; Ramu, Andy

2017-12-01

A new salicylaldehyde derived 2,4-diiodo-6-((2-phenylaminoethylimino)methyl)phenol Schiff base(L) and its transition metal complexes of the type MLCl where, M = Cu(II), Ni(II), Co(II), Mn(II) and Zn(II) have been synthesized. The coordination mode of Schiff base holding NNO donor atoms with metal ions was well investigated by elemental analysis, ESI-mass as well as IR, UV-vis, CV and NMR spectral studies. The binding efficiency and mode of these complexes with biological macromolecules viz., herring sperm DNA (HS- DNA) and bovine serum albumin (BSA) have been explored through various spectroscopic techniques. The characteristic changes in absorption, emission and, circular dichroism spectra of the complexes with DNA indicate the noticeable interaction between them. From the all spectral information complexes could interact with DNA via non-intercalation mode of binding. The hyperchromisim in absorption band and hypochromisim in emission intensity of BSA with different complex concentrations shown significant information, and the binding affinity value has been predicted from Stern-Volmer plots. Further, all the complexes could cleave the circular plasmid pUC19 DNA efficiently by using an activator H2O2. The ligand and all metal(II) complexes showed good antibacterial activities. The molecular docking studies of the complexes with DNA were performed in order to make a comparison and conclusion with spectral technic results.

Iron deficiency in blood donors

Directory of Open Access Journals (Sweden)

Rodolfo Delfini Cançado

Full Text Available CONTEXT: Blood donation results in a substantial loss of iron (200 to 250 mg at each bleeding procedure (425 to 475 ml and subsequent mobilization of iron from body stores. Recent reports have shown that body iron reserves generally are small and iron depletion is more frequent in blood donors than in non-donors. OBJECTIVE: The aim of this study was to evaluate the frequency of iron deficiency in blood donors and to establish the frequency of iron deficiency in blood donors according to sex, whether they were first-time or multi-time donors, and the frequency of donations per year. DESIGN: From September 20 to October 5, 1999, three hundred blood donors from Santa Casa Hemocenter of São Paulo were studied. DIAGNOSTIC TESTS: Using a combination of biochemical measurements of iron status: serum iron, total iron-binding capacity, transferrin saturation index, serum ferritin and the erythrocyte indices. RESULTS: The frequency of iron deficiency in blood donors was 11.0%, of whom 5.5% (13/237 were male and 31.7% (20/63 female donors. The frequency of iron deficiency was higher in multi-time blood donors than in first-time blood donors, for male blood donors (7.6% versus 0.0%, P < 0.05 and female ones (41.5% versus 18.5%, P < 0.05. The frequency of iron deficiency found was higher among the male blood donors with three or more donations per year (P < 0.05 and among the female blood donors with two or more donations per year (P < 0.05. CONCLUSIONS: We conclude that blood donation is a very important factor for iron deficiency in blood donors, particularly in multi-time donors and especially in female donors. The high frequency of blood donors with iron deficiency found in this study suggests a need for a more accurate laboratory trial, as hemoglobin or hematocrit measurement alone is not sufficient for detecting and excluding blood donors with iron deficiency without anemia.

Syntheses, structures and photoluminescent properties of Zn(Ⅱ)/Co(Ⅱ) coordination polymers based on flexible tetracarboxylate ligand of 5,5′-(butane-1,4-diyl)-bis(oxy)-di isophthalic acid

Energy Technology Data Exchange (ETDEWEB)

Gao, Yan-Peng [Inner Mongolia Key Lab Chem & Phys Rare Earth Mat, College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Department of Chemistry and Chemical Engineering, Ordos College of Inner Mongolia University, Ordos 017000 (China); Department of Chemistry and Chemical Engineering, Ordos Applied Technology College, Ordos 017000 (China); Guo, Le [Department of Chemistry and Chemical Engineering, Ordos College of Inner Mongolia University, Ordos 017000 (China); Department of Chemistry and Chemical Engineering, Ordos Applied Technology College, Ordos 017000 (China); Dong, Wei; Jia, Min; Zhang, Jing-Xue; Sun, Zhong [Inner Mongolia Key Lab Chem & Phys Rare Earth Mat, College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Chang, Fei, E-mail: ndchfei@imu.edu.cn [Inner Mongolia Key Lab Chem & Phys Rare Earth Mat, College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China)

2016-08-15

Three new mixed-ligand metal-organic frameworks based on 5,5′-(butane-1,4- diyl)-bis(oxy)-diisophthalic acid and transitional metal cations with the help of two ancillary bridging N-donor pyridyl and imidazole linkers, [Zn(L){sub 0.5}(4,4′-bpy)]·2(H{sub 2}O) (1), [M(L){sub 0.5}(bib)]·4(H{sub 2}O) (M = Zn (2), Co (3)), (4,4′-bpy=4,4′–bipyridine, bib=1,4-bis (1H-imidazol-1-yl)-butane), have been synthesized under solvothermal conditions. Their structures and properties were determined by single-crystal and powder X-ray diffraction analyses, IR spectra, elemental analyses and thermogravimetric analyses (TGA). Compounds 1–3 display a 3D 3-fold interpenetrated frameworks linked by the L{sup 4−} ligands, ancillary N-donor linkers and the free water molecules in the crystal lattice. Topological analysis reveals that 1–3 are a (4,4)-connected bbf topology net with the (6{sup 4}·8{sup 2})(6{sup 6}) topology. The effects of the L{sup 4−} anions, the N-donor ligands, and the metal ions on the structures of the coordination polymers have been discussed. Furthermore, luminescence properties and thermogravimetric properties of these compounds were investigated. - Graphical abstract: Three new compounds of MOFs have been prepared and characterized. The luminescence properties and thermogravimetric properties of compounds were investigated. Display Omitted.

Correlation between donor age and organs transplanted per donor: our experience in Japan.

Science.gov (United States)

Ashikari, J; Omiya, K; Konaka, S; Nomoto, K

2014-05-01

The shortage of available organs for transplantation is a worldwide issue. To maximize the number of transplantations, increasing the number of organs transplanted per donor (OTPD) is widely recognized as an important factor for improving the shortage. In Japan, we have had 211 donors, 1112 organs transplanted, and 924 recipients receiving the transplants, resulting in 4.4 ± 1.4 recipients receiving transplants per donor and 5.3 ± 1.6 OTPD as of February 2013. Because donor age is a well-recognized factor of donor suitability, we analyzed the correlation between donor age group and OTPD. Only the age group 60 to 69 years and the age group 70 to 79 years were significantly different (P donor under age 70 years has the potential to donate 4.6 to 6.7 organs. Copyright © 2014 Elsevier Inc. All rights reserved.

Achieving donor management goals before deceased donor procurement is associated with more organs transplanted per donor.

Science.gov (United States)

Malinoski, Darren J; Daly, Michael C; Patel, Madhukar S; Oley-Graybill, Chrystal; Foster, Clarence E; Salim, Ali

2011-10-01

There is a national shortage of organs available for transplantation. Implementation of preset donor management goals (DMGs) to improve outcomes is recommended, but uniform practices and data are lacking. We hypothesized that meeting DMGs before organ procurement would result in more organs transplanted per donor (OTPD). The eight organ procurement organization in United Network for Organ Sharing Region 5 selected 10 critical care end points as DMGs. Each organ procurement organization submitted retrospective data from 40 standard criteria donors. "DMGs met" was defined as achieving any eight DMGs before procurement. The primary outcome was ≥4 OTPD. Binary logistic regression was used to determine independent predictors of ≥4 OTPD with a pdonors had 3.6±1.6 OTPD. Donors with DMGs met had more OTPD (4.4 vs. 3.3, p50% (OR=4.0), Pao2:FIO2>300 (OR=4.6), and serum sodium 135 to 160 mEq/L (OR=3.4). Meeting DMGs before procurement resulted in more OTPD. Donor factors and critical care end points are independent predictors of organ yield. Prospective studies are needed to determine the true impact of each DMG on the number and function of transplanted organs.

Patients Lacking a KIR-Ligand of HLA Group C1 or C2 Have a Better Outcome after Umbilical Cord Blood Transplantation

Directory of Open Access Journals (Sweden)

Carmen Martínez-Losada

2017-07-01

Full Text Available Donor natural killer (NK cells can destroy residual leukemic cells after allogeneic hematopoietic stem cell transplantation. This effect is based on the interaction of killer-cell immunoglobulin-like receptors (KIR of donor NK cells with ligands of the major histocompatibility complex found on the surface of the target cells. HLA-C1 subtypes provide the ligand for KIR2DL2 and KIR2DL3 and the HLA-C2 subtypes for KIR2DL1. We have studied the probability of relapse (PR after single-unit unrelated cord blood transplantation (UCBT in relation to the potential graft-vs.-leukemia effect mediated by NK cells present in the umbilical cord blood (UCB by analyzing KIR-ligand and HLA-C typing of the receptor. Data from 33 consecutive patients given a single unit UCBT were included. We have considered two groups of patients based on the absence or the presence of one of the C-ligands for inhibitory KIR and the incompatibility HLA-C1/2 between UCB and patients. Group 1 (n = 21: the patient lacks a C-ligand for inhibitory KIR present in UCB NK cells, i.e., patients homozygous C1/C1 or C2/C2. Group 2 (n = 12: patients heterozygous C1/C2 in which KIR-mediated graft-vs.-leukemia effect is not expected (presence of both C ligands for inhibitory KIR in the receptor. With a median follow-up post-UCBT of 93 months, patients with absence of a C-ligand for inhibitory KIRs (Group 1 showed a lower actuarial PR than patients with both C-ligands (group 2: 21 ± 10 vs. 68 ± 18% at 2 year and 36 ± 13 vs. 84 ± 14% at 5 years (p = 0.025, respectively. In patients with acute lymphoblastic leukemia, the 2-year PR was 36 ± 21% for group 1 and 66 ± 26% for 2 (p = 0.038. Furthermore, group 1 had a lower incidence of grades II–IV acute graft-vs.-host disease (p = 0.04. In the setting of UCBT, the absence of a C-ligand (C1 or C2 of inhibitory KIR in the patient is associated with lower PR, which is probably due to the graft

The effects of donor stage on the survival and function of embryonic striatal grafts in the adult rat brain; II. Correlation between positron emission tomography and reaching behaviour

International Nuclear Information System (INIS)

Dunnett, S.B.; Brooks, D.J.; Ashworth, S.; Opacka-Juffrey, J.; Myers, R.; Hume, S.P.; Torres, E.M.; Fricker, R.A.

1997-01-01

Grafts of embryonic striatal primordia are able to elicit behavioural recovery in rats which have received an excitotoxic lesion to the striatum, and it is believed that the P zones or striatal-like tissue within the transplants play a crucial role in these functional effects. We performed this study to compare the effects of different donor stage of embryonic tissue on both the morphology (see accompanying paper) and function of striatal transplants. Both the medial and lateral ganglionic eminence was dissected from rat embryos of either 10 mm, 15 mm, 19 mm, or 23 mm crown-rump length, and implanted as a cell suspension into adult rats which had received an ibotenic acid lesion 10 days prior to transplantation. After four months the animals were tested on the 'staircase task' of skilled forelimb use. At 10-14 months rats from the groups which had received grafts from 10 mm or 15 mm donor embryos were taken for positron emission tomography scanning in a small diameter postiron emission tomography scanner, using ligands to the dopamine D 1 and D 2 receptors, [ 11 C]SCH 23390 and [ 11 C]raclopride, respectively. A lesion-alone group was also scanned with the same ligands for comparison. Animals which had received transplants from the 10 mm donors showed a significant recovery with their contralateral paw on the 'staircase test'. No other groups showed recovery on this task. Similarly, the animals with grafts from the youngest donors showed a significant increase in D 1 and D 2 receptor binding when compared to the lesion-alone group. No increase in signal was observed with either ligand in the group which had received grafts from 15 mm donors. Success in paw reaching showed a strong correlation to both the positron emission tomography signal obtained and the P zone volume of the grafts.These results suggest that striatal grafts from younger donors (10 mm CRL) give greater behavioural recovery than grafts prepared from older embryos. This recovery is due to both the

A simplified donor risk index for predicting outcome after deceased donor kidney transplantation.

Science.gov (United States)

Watson, Christopher J E; Johnson, Rachel J; Birch, Rhiannon; Collett, Dave; Bradley, J Andrew

2012-02-15

We sought to determine the deceased donor factors associated with outcome after kidney transplantation and to develop a clinically applicable Kidney Donor Risk Index. Data from the UK Transplant Registry on 7620 adult recipients of adult deceased donor kidney transplants between 2000 and 2007 inclusive were analyzed. Donor factors potentially influencing transplant outcome were investigated using Cox regression, adjusting for significant recipient and transplant factors. A United Kingdom Kidney Donor Risk Index was derived from the model and validated. Donor age was the most significant factor predicting poor transplant outcome (hazard ratio for 18-39 and 60+ years relative to 40-59 years was 0.78 and 1.49, respectively, Pinformed consent.

Effect of Ligand Field Tuning on the SMM Behavior for Three Related Alkoxide-Bridged Dysprosium Dimers.

Science.gov (United States)

Peng, Yan; Mereacre, Valeriu; Baniodeh, Amer; Lan, Yanhua; Schlageter, Martin; Kostakis, George E; Powell, Annie K

2016-01-04

The synthesis and characterization of three Dy2 compounds, [Dy2(HL1)2(NO3)4] (1), [Dy2(L2)2(NO3)4] (2), and [Dy2(HL3)2(NO3)4] (3), formed using related tripodal ligands with a central tertiary amine bearing picolyl and alkoxy arms, 2-[(2-hydroxy-ethyl)-pyridin-2-ylmethylamino]-ethanol (H2L1), 2-(bis-pyridin-2-ylmethylamino)-ethanol (HL2), and 2-(bis-pyridin-2-ylmethylamino)-propane-1,3-diol (H2L3), are reported. The compounds are rare examples of alkoxide-bridged {Dy2} complexes and display capped square antiprism coordination geometry around each Dy(III) ion. Changes in the ligand field environment around the Dy(III) ions brought about through variations in the ligand donors can be gauged from the magnetic properties, with compounds 1 and 2 showing antiparallel coupling between the Dy(III) ions and 3 showing parallel coupling. Furthermore, slow relaxation of the magnetization typical of SMM behavior could be observed for compounds 2 and 3, suggesting that small variations in the ligand field can have a significant influence on the slow relaxation processes responsible for SMM behavior of Dy(III)-based systems.

Synthesis and Crystal Structures of Ni(II)/(III) and Zn(II) Complexes with Schiff Base Ligands

International Nuclear Information System (INIS)

Koo, Bon Kweon

2013-01-01

Coordination polymers are of great interest due to their intriguing structural motifs and potential applications in optical, electronic, magnetic, and porous materials. The most commonly used strategy for designing such materials relies on the utilization of multidentate N- or Odonor ligands which have the capacity to bridge between metal centers to form polymeric structures. The Schiff bases with N,O,S donor atoms are an useful source as they are readily available and easily form stable complexes with most transition metal ions. Schiff bases are also important intermediates in synthesis of some bioactive compounds and are potent anti-bacterial, anti-fungal, anticancer and antiviral compounds. In this work, the Schiff bases, Hapb and Hbpb, derived from 2-acetylpyridene or 2-benzoylpyridine and benzhydrazide were taken as trifunctional (N,N,O) monobasic ligand (Scheme 1). This ligand is of important because the π-delocalization of charge and the configurational flexibility of their molecular chain can give rise to a great variety of coordination modes. Although many metal.Schiff base complexes have been reported, the 1D, 2D, and 3D networks of coordination polymers linked through the bridging of ligands such as dicyanamide, N(CN) 2 - as coligand have been little published. In the process of working to extend the dimensionality of the metal-Schiff base complexes using benzilic acid as a bridging ligand, we obtained three simple metal (II)/(III) complexes of acetylpyridine/2-benzoyl pyridine based benzhydrazide ligand. Therefore, we report here the synthesis and crystal structures of the complexes

Two novel mixed-ligand complexes containing organosulfonate ligands.

Science.gov (United States)

Li, Mingtian; Huang, Jun; Zhou, Xuan; Fang, Hua; Ding, Liyun

2008-07-01

The structures reported herein, viz. bis(4-aminonaphthalene-1-sulfonato-kappaO)bis(4,5-diazafluoren-9-one-kappa(2)N,N')copper(II), [Cu(C(10)H(8)NO(3)S)(2)(C(11)H(6)N(2)O)(2)], (I), and poly[[[diaquacadmium(II)]-bis(mu-4-aminonaphthalene-1-sulfonato)-kappa(2)O:N;kappa(2)N:O] dihydrate], {[Cd(C(10)H(8)NO(3)S)(2)(H(2)O)(2)].2H(2)O}(n), (II), are rare examples of sulfonate-containing complexes where the anion does not fulfill a passive charge-balancing role, but takes an active part in coordination as a monodentate and/or bridging ligand. Monomeric complex (I) possesses a crystallographic inversion center at the Cu(II) atom, and the asymmetric unit contains one-half of a Cu atom, one complete 4-aminonaphthalene-1-sulfonate (ans) ligand and one 4,5-diazafluoren-9-one (DAFO) ligand. The Cu(II) atom has an elongated distorted octahedral coordination geometry formed by two O atoms from two monodentate ans ligands and by four N atoms from two DAFO molecules. Complex (II) is polymeric and its crystal structure is built up by one-dimensional chains and solvent water molecules. Here also the cation (a Cd(II) atom) lies on a crystallographic inversion center and adopts a slightly distorted octahedral geometry. Each ans anion serves as a bridging ligand linking two Cd(II) atoms into one-dimensional infinite chains along the [010] direction, with each Cd(II) center coordinated by four ans ligands via O and N atoms and by two aqua ligands. In both structures, there are significant pi-pi stacking interactions between adjacent ligands and hydrogen bonds contribute to the formation of two- and three-dimensional networks.

The impact of disclosure on donor gamete participants: donors, intended parents and offspring.

Science.gov (United States)

Greenfeld, Dorothy A

2008-06-01

The present review examines recent publications that provide insight into how the trend toward nonanonymity and disclosure in gamete donation impacts donors, intended parents, and their donor-conceived children. Recent findings show an increase in donor programs that offer open-identity between donors and offspring. The psychological needs of gamete donors and their attitudes toward disclosure are increasingly given consideration. Qualitative research on how parents of donor gamete offspring make decisions about disclosure reveals that even when couples initially disagree about disclosing to offspring, most ultimately come to a united disclosure decision. The literature on the impact of disclosure on donor gamete offspring has extended to include children conceived through embryo donation and children born as a result of surrogacy. The absence of genetic or gestational link between parents and their child does not have a negative impact on parent-child relationships. Parents through surrogacy tend to disclose the method of family creation to their child, whereas parents through embryo donation tend to be secretive about their child's origins. The trend toward greater openness in gamete donation has been accompanied by an increase in programs offering open-identity donation. In addition, the psychological needs of gamete donors and their attitudes toward disclosure are increasingly being given consideration. Parents of donor gamete offspring give careful thought to their disclosure decisions, and the psychological well being of donor-conceived children does not seem to be impacted by those decisions.

The chemistry of polypyridine complexes of ruthenium. Communication 5. Electronic structure of mixed-ligand bipyridyl-diphosphine complexes of ruthenium(2)

International Nuclear Information System (INIS)

Sizova, O.V.; Ivanova, N.V.; Ershov, A.Yu.

2001-01-01

Comparative analysis of donor-acceptor abilities of diphosphine ligands for two series of complex compounds: cis-[Ru(bpy) 2 (LL) q+ [LL=2,2'-bipyridyl(bpy), o-benzoquinonediimine (bqdi), cis-1,2-bis(diphenylphosphino)ethane, cis-1,2-bis(diphenylphosphino)ethylene (dppen), (NH 3 ) 2 and (CO) 2 ] and [Ru(NH 3 ) 4 (LL)] 2+ (LL = bpy, dppen and bqdi) was carried out on the basis of results of quantum chemical calculations. It is shown that diphosphines are the strongest σ-donors; their π-acceptor abilities stemming from d-orbitals of phosphorus are comparable in value with π-acceptor abilities of 2,2'-bipyridyl, being essentially lower than those of o-benzoquinonediimine and carbonyl [ru

SYNTHESIS, SPECTRAL AND THERMAL PROPERTIES OF SOME ...

African Journals Online (AJOL)

The infrared spectral studies reveal that the ligand HNAAPTS is coordinated in neutral tridentate (N,N,S) fashion. The coordination number of Th(IV) in these coordination compounds varies from 6, 8, 10 or 11; while for U(VI) the coordination number are 8, 9 or 10. Thermal stabilities of these complexes were investigated ...

Differences in social representation of blood donation between donors and non-donors: an empirical study.

Science.gov (United States)

Guarnaccia, Cinzia; Giannone, Francesca; Falgares, Giorgio; Caligaris, Aldo Ozino; Sales-Wuillemin, Edith

2015-11-04

Both donors and non-donors have a positive image of blood donation, so donors and non-donors do not differ regarding their views on donation but do differ in converting their opinion into an active deed of donation. Several studies have identified altruism and empathy as the main factors underlying blood donation. However, a mixture of various motivational factors mould the complex behaviour of donation. This paper presents an exploratory study on differences of social representations of blood donation between blood donors and non-donors, in order to understand the reasons that bring someone to take the decision to become a blood donor. Participants filled in the Adapted Self-Report Altruism Scale, Toronto Empathy Questionnaire and answered a test of verbal association. Descriptive and correlation analyses were carried out on quantitative data, while a prototypic analysis was used for qualitative data. The study was carried out on a convenience sample of 786 individuals, 583 donors (mean age: 35.40 years, SD: 13.01 years; 39.3% female) and 203 non-donors (mean age: 35.10 years, SD: 13.30 years; 67.5% female). Social representations of donors seem to be more complex and articulated than those of non-donors. The terms that appear to be central were more specific in donors (life, needle, blood, help, altruism were the words most associated by non-donors; life, aid, altruism, solidarity, health, love, gift, generosity, voluntary, control, needed, useful, needle were the words most associated by donors). Furthermore, non-donors associated a larger number of terms referring to negative aspects of blood donation. Aspects related to training and the accuracy of any information on blood donation seem to be important in the decision to become a donor and stabilise the behaviour of donation over time, thus ensuring the highest levels of quality and safety in blood establishments.

Synthesis and structural studies of first row transition metal complexes of N-(2-nitro-benzilidine-3-hydrazino quinoxaline-2-one

Directory of Open Access Journals (Sweden)

P.V. Anantha Lakshmi

2008-12-01

Full Text Available Cr(III, Mn(II, Fe(III, Co(II, Ni(II and Cu(II complexes of N-(2-nitro-benzilidene-3-hydrazino quinoxaline-2-one (NBHQO have been synthesized and characterized by elemental analysis, conductance, thermal, spectral and magnetic data. NBHQO acts as a bidentate ON donor in all the complexes except in Ni(II complex in which it acts as a tridentate ONO donor. Octahedral geometries have been proposed for all the complexes except for Cu(II complex to which the square planar geometry is assigned.

Linear uranium metallocenes with polydentate aromatic nitrogen ligands

International Nuclear Information System (INIS)

Berthet, Jean-Claude; Thuery, Pierre; Ephritikhine, Michel; Maynadie, Jerome

2010-01-01

Treatment of [Cp 2 *U(NCMe) 5 ]X 2 [Cp* = C 5 Me 5 , X = BPh 4 (1) or I (1')] or Cp 2 *UI 2 in acetonitrile with the polydentate aromatic nitrogen bases phen, terpy and R 4 btbp led to the formation of the linear uranium metallocenes [Cp 2 *U(NCMe) 3 (phen)]X 2 [X = BPh 4 (2), I (2')], [Cp 2 *U(NCMe) 2 (terpy)][BPh 4 ] 2 (4), [Cp 2 *U(NCMe)(Me 4 btbp)][BPh 4 ] 2 (5) and [Cp 2 *U(NCMe)(CyMe 4 btbp)][X] 2 , [X = BPh 4 (6), I (6')], [phen 1, 10-phenanthroline, terpy = 2, 2':6, 2''-terpyridine, Me 4 btbp 6, 6'-bis-(3, 3, 6, 6-tetramethyl-1, 2, 4-triazin-3-yl)-2, 2'-bipyridine, CyMe 4 btbp = 6, 6'-bis-(3, 3, 6, 6-tetramethyl-cyclohexane-1, 2, 4-triazin-3-yl)-2, 2'-bipyridine]. The bent metallocene [Cp 2 *U(phen) 2 ][BPh 4 ] 2 (3) was isolated from the reaction of 1 and two molar equivalents of phen in THF. The X-ray crystal structures of 2.2MeCN, 3.2THF, 4 and 6'center dot 2MeCN were determined. (authors)

Infrared multiple photon dissociation spectroscopy of sodium and potassium chlorate anions.

Science.gov (United States)

Dain, Ryan P; Leavitt, Christopher M; Oomens, Jos; Steill, Jeffrey D; Groenewold, Gary S; Van Stipdonk, Michael J

2010-01-01

The structures of gas-phase, metal chlorate anions with the formula [M(ClO(3))(2)](-), M = Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental vibrational spectra for the two species with those predicted by density functional theory (DFT) and involve conformations that feature either bidentate or tridentate coordination of the cation by chlorate. Our results strongly suggest that a structure in which both chlorate anions are bidentate ligands is preferred for [Na(ClO(3))(2)](-). However, for [K(ClO(3))(2)](-) the best agreement between experimental and theoretical spectra is obtained from a composite of predicted spectra for which the chlorate anions are either both bidentate or both tridentate ligands. In general, we find that the overall accuracy of DFT calculations for prediction of IR spectra is dependent on both functional and basis set, with best agreement achieved using frequencies generated at the B3LYP/6-311+g(3df) level of theory. Copyright 2009 John Wiley & Sons, Ltd.

Direct and quantitative characterization of dynamic ligand exchange between coordination-driven self-assembled supramolecular polygons.

Science.gov (United States)

Zheng, Yao-Rong; Stang, Peter J

2009-03-18

The direct observation of dynamic ligand exchange between Pt-N coordination-driven self-assembled supramolecular polygons (triangles and rectangles) has been achieved using stable (1)H/(2)D isotope labeling of the pyridyl donors and electrospray ionization mass spectrometry combined with NMR spectroscopy. Both the thermodynamic and kinetic aspects of such exchange processes have been established on the basis of quantitative mass spectral results. Further investigation has shown that the exchange is highly dependent on experimental conditions such as temperature, solvent, and the counteranions.

Donor-derived HLA antibody production in patients undergoing SCT from HLA antibody-positive donors.

Science.gov (United States)

Taniguchi, K; Yoshihara, S; Maruya, E; Ikegame, K; Kaida, K; Hayashi, K; Kato, R; Inoue, T; Fujioka, T; Tamaki, H; Okada, M; Onuma, T; Fujii, N; Kusunoki, Y; Soma, T; Saji, H; Ogawa, H

2012-10-01

Pre-existing donor-specific HLA antibodies in patients undergoing HLA-mismatched SCT have increasingly been recognized as a risk factor for primary graft failure. However, the clinical implications of the presence of HLA antibodies in donors remain unknown. We prospectively examined 123 related donors for the presence of HLA antibodies by using a Luminex-based single antigen assay. Of these, 1/57 (1.8%) male, 6/27 (22%) parous female and 0/39 (0%) nonparous female donors were HLA antibody-positive. Then, we determined the presence of HLA antibodies in seven patients who received SCT from antibody-positive donors. Of these, four became HLA antibody-positive after SCT. The specificities of the antibodies that emerged in the patients closely resembled those of the antibodies found in the donors, indicating their production by donor-derived plasma cells. Moreover, the kinetics of the HLA antibody levels were similar in all four patients: levels started increasing within 1 week after SCT and peaked at days 10-21, followed by a gradual decrease. These results suggest that donor-derived HLA antibody production frequently occurs in patients undergoing SCT from antibody-positive donors. Further studies are warranted for clarifying the clinical significance of donor-derived HLA antibodies, including the role of these antibodies in post transplant platelet transfusion refractoriness.

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the Caribbean Sea in support of the Integrated Global Ocean Services System (IGOSS) project from 1975-04-28 to 1975-05-08 (NODC Accession 7600704)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Recent advances in photoinduced donor/acceptor copolymerization

International Nuclear Information System (INIS)

Joensson, S.; Viswanathan, K.; Hoyle, C.E.; Clark, S.C.; Miller, C.; Morel, F.; Decker, C.

1999-01-01

Photoinitiated free radical polymerization of donor (D)/acceptor (A) type monomers has gained considerable interest due to the possibility to efficiently photopolymerize non-acrylate based systems. Furthermore, this photoinduced alternating copolymerization can be accomplished without the presence of a conventional free radical generating photoinitiator. In the past, we have shown that the structural influences in the direct photolysis of N-Alkyl and N-Arylmaleimides as well as their corresponding ground state charge transfer complexes (CTC) with suitable donors have carefully been investigated. For certain combinations of A and D type monomers, a direct photolysis of the ground state complex or the excitation of the acceptor, followed by the formation of an exciplex, has been shown to initiate the copolymerization. Herein, we show that the main route of initiation is based on inter or intra molecular H-abstraction from an excited state maleimide, whereby no exciplex formation takes place. H-abstraction will predominantly take place in systems where easily abstractable hydrogens are present. Our laser flash photolysis investigation, ESR (A. Hiroshi, I. Takasi, T. Nosi, Macromol. Chem. 190 (1989) 2821) and phosphorescence emissions (K.S. Chen, T. Foster, J.K.S. Wan, J. Phys. Chem. 84 (1980) 2473; C.J. Seliskar, S.P. McGlynn, J. Chem. Phys. 55 (1971) 4337) studies show that triplet excited states of N-alkyl substituted maleimides (RMI), which are well known strong precursors for direct H-abstractions from aliphatic ethers and secondary alcohols, are formed upon excitation. Rates of copolymerization and degrees of conversion for copolymerization of maleimide/vinyl ether pairs in air and nitrogen have been measured as a function of hydrogen abstractability of the excited triplet state MI as well as the influence of concentration and hydrogen donating effect of the hydrogen donor

The effect of whole-blood donor adverse events on blood donor return rates.

Science.gov (United States)

Newman, Bruce H; Newman, Daniel T; Ahmad, Raffat; Roth, Arthur J

2006-08-01

Some blood donation-related adverse events (AEs) can negatively impact the blood donor return rate (BDRR) and decrease donor retention. One-thousand randomly selected whole-blood donors were interviewed 3 weeks after a 525-mL index whole-blood donation for seven AEs. The number of return visits and duration of follow-up were recorded for each of the 1000 donors. A negative binomial regression analysis was used to determine the contribution of the four most common AEs to the BDRR, and interactions between these AEs were also evaluated. The four most common AEs were bruise alone (15.1%), sore arm "alone" (7.0%), fatigue "alone" (5.1%), and donor reaction "alone" (4.2%), where "alone" is defined to also include donors who had a bruise but no other AE. The estimated BDRR for donations without AEs was 1.32 visits per year. The estimated BDRRs for the four most common AEs were: bruise alone, 1.32 visits per year; sore arm alone, 1.30 visits per year (2% reduction in BDRR); fatigue alone, 1.06 visits per year (20% reduction in BDRR); and donor reaction alone, 0.87 visits per year (34% reduction in BDRR). The BDRR for donor reaction, fatigue, and sore arm together was 0.20 visits per year (85% reduction in BDRR). Donor reaction had the most negative impact on the BDRR. There appears to be a synergistic effect between donor reaction, fatigue, and sore arm. Theoretically, amelioration of some AEs has the potential to improve BDRRs.

PEGylated N-methyl-S-methyl dithiocarbazate as a new reagent for the high-yield preparation of nitrido Tc-99m and Re-188 radiopharmaceuticals

Energy Technology Data Exchange (ETDEWEB)

Boschi, Alessandra, E-mail: alessandra.boschi@unife.i [Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara (Italy); Massi, Alessandro [Department of Chemistry, University of Ferrara, 44100 Ferrara (Italy); Uccelli, Licia; Pasquali, Micol; Duatti, Adriano [Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara (Italy)

2010-11-15

A novel nitrido nitrogen atom donor for the preparation of {sup 99m}Tc and {sup 188}Re radiopharmaceuticals containing a metal-nitrogen multiple bond is presented. HO{sub 2}C-PEG{sub 600}-DTCZ was obtained by conjugation of N-methyl-S-methyl dithiocarbazate [H{sub 2}N-N(CH{sub 3})-C({identical_to}S)SCH{sub 3}, HDTCZ] with polyethylene glycol 600 (PEG{sub 600}). Asymmetrical heterocomplexes of the type [M(N)(PNP)(B)]{sup 0/+} (M={sup 99m}Tc, {sup 188}Re; PNP=diphosphine ligands, B=DBODC, DEDC, NSH, H{sub 2}OS, CysNAc, HDTCZ) and symmetrical nitride compounds of the type [M(N)(L){sub 2}] (L=DEDC, DPDC) have been prepared in high yield by using the newly designed nitride nitrogen atom donor HO{sub 2}C-PEG{sub 600}-DTCZ. A two-step procedure was applied for preparing the above symmetrical and asymmetrical complexes. The first step involved the preliminary formation of a mixture of nitride Tc-99m or Re-188 precursors, which contained the [M{identical_to}N]{sup 2+} core, through reduction of generator-eluted {sup 99m}Tc-pertechnetate or {sup 188}Re-perrhenate with thin (II) chloride in the presence of HO{sub 2}C-PEG{sub 600}-DTCZ. In the second step, the intermediate mixture was converted either in the final mixed asymmetrical complex by the simultaneous addition of diphosphine ligand and the suitable bidentate ligand B, or in the final symmetrical complex by the only addition of the bidentate ligand L. It was also demonstrated that the novel water-soluble nitride nitrogen atom donor HO{sub 2}C-PEG{sub 600}-DTCZ did not show coordinating properties toward the M{identical_to}N ({sup 99m}Tc, {sup 188}Re) core. Biodistribution studies in rats of the hitherto unreported [{sup 99m}Tc(N)(PNP{sub 3})DTCZ]{sup +} and [{sup 99m}Tc(N)(PNP{sub 5})DTCZ]{sup +} complexes showed that they selectively localize in the myocardium of rats with a favourable heart-to-lung and heart-to-liver uptake ratios. In particular, the heart-to-lung and heart-to-liver uptake ratios dramatically

ِAnalysis of donor motivations in living donor liver transplantation

Directory of Open Access Journals (Sweden)

Hesham eAbdeldayem

2014-07-01

Full Text Available Objectives: The introduction of the living donor liver transplantation (LDLT in Egypt as in elsewhere, has raised important psychological conflicts and ethical questions. The objective of this study was to get better understanding of the potential donors’ motives towards LDLT.Methods:This study was conducted on consecutive 193 living –liver donors who underwent partial hepatectomy as donors for LDLT during the period between April 2003 and January 2013, at the National Liver Institute Menoufeyia University, Egypt. Potential donors were thoroughly evaluated preoperatively through a screening questionnaire and interviews as regard their demographic data, relationship to the potential recipient and motives towards proceeding to surgery. They were assured that the information shared between them and the transplant centre is confidential. Results.The donors’ mean age was 25.53± 6.39 years with a range of 18-45 years. Males represented 64.7 % and females were 35.3%. The most common donors (32.1%, n_62, were sons and daughters to their parents (sons: n_43, daughters: n_19 while parents to their offsprings represent 15% (mothers: n_21, fathers: n_8. Brothers and sisters represent 16.5 % (brothers: n_22, sisters: n_10. Nephews & nieces giving their uncles or aunts were 14%. The number of wives donating to their husbands was 11 (5.7%. Interestingly, there was no single husband who donated his wife. Among the remaining donors, there were 11 cousins & one uncle. Unrelated donors were 20 (10.4%. Several factors seemed to contribute to motivation for donation: the seriousness of the potential recipient condition, the relationship and personal history of the donor to the potential recipient, the religious beliefs, the trust in the health care system, and family dynamics and obligations.Conclusions. Absolute absence of coercion on the living-liver donor’s motives may not be realistic because of the serious condition of the potential recipient. It is

Modeling Electron Competition among Nitrogen Oxides Reduction and N₂O Accumulation in Hydrogenotrophic Denitrification

DEFF Research Database (Denmark)

Liu, Yiwen; Ngo, Huu Hao; Guo, Wenshan

2018-01-01

Hydrogenotrophic denitrification is a novel and sustainable process for nitrogen removal, which utilizes hydrogen as electron donor and carbon dioxide as carbon source. Recent studies have shown that nitrous oxide (N2O), a highly undesirable intermediate and potent greenhouse gas, can accumulate...

Evaluation of several novel diamide based ligands for selective extraction of tetravalent plutonium

Energy Technology Data Exchange (ETDEWEB)

Sivaramakrishna, Mallampalli; Nayak, Shashikant K. [Heavy Water Board, V.S. Bhavan, Mumbai (India); Raut, Dhaval R.; Mohapatra, Prasanta K. [Bhabha Atomic Research Center, Mumbai (India). Radiochemistry Division; Nayak, Sandip K. [Bhabha Atomic Research Center, Mumbai (India). Bioorganic Division

2017-06-01

The present paper describes the selective extraction of tetravalent plutonium employing several diamide ligands containing aromatic spacer groups. The ligands containing two amide functional groups attached to a 2,4,6-tri-phenyl pyridine moiety with different substituents viz.; L{sub I} (iso-butyl), L{sub II}(n-butyl), L{sub III}(n-octyl), L{sub IV} (2-ethylhexyl) at the amidic nitrogen atom were evaluated for the extraction of Pu(IV) using their nitrobenzene solutions. The distribution ratio values of Pu(IV) with the diamide ligands followed the order: L{sub II}>L{sub I}>L{sub III}>L{sub IV} and were significantly higher than those of metal ions such as Cs(I), Sr(II), Am(III) and Eu(III). The distribution ratio values of U(VI) were about 2-3 orders magnitude lower than those of Pu(IV). The extraction and stripping kinetics were found to be moderately fast and it took less than 30 min (less than 5 min for L{sub I} and L{sub IV}) to obtain equilibrium D values. The extraction was found to be increasing with the aqueous phase nitric acid concentration conforming to a solvation mechanism of extraction. The extracted species contained two ligand molecules for L{sub I} and L{sub II} while monosolvates were observed for the other two extractants. The ligands showed good radiation stability up to an absorbed dose of 630 kGy.

Characterization of partitioning relevant lanthanide and actinide complexes by NMR spectroscopy; Charakterisierung von partitioningrelevanten Lanthaniden- und Actinidenkomplexen mittels NMR-Spektroskopie

Energy Technology Data Exchange (ETDEWEB)

Adam, Christian

2016-01-15

In the present work the interaction of N-donor ligands, such as 2,6-Bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine (nPrBTP) and 2,6-Bis(5-(2,2-dimethylpropyl)1H-pyrazol)-3-yl-pyridine (C5-BPP), with trivalent lanthanide and actinide ions was studied. Ligands of this type show a high selectivity for the separation of trivalent actinide ions over lanthanides from nitric acid solutions. However, the reason for this selectivity, which is crucial for future partitioning and transmutation strategies for radioactive wastes, is still unknown. So far, the selectivity of some N-donor ligands is supposed to be an effect of an increased covalency in the actinide-ligand bond, compared to the lanthanide compounds. NMR spectroscopy on paramagnetic metal complexes is an excellent tool for the elucidation of bonding modes. The overall paramagnetic chemical shift consists of two contributions, the Fermi Contact Shift (FCS), due to electron spin delocalisation through covalent bonds, and the Pseudo Contact Shift (PCS), which describes the dipolar coupling of the electron magnetic moment and the nuclear spin. By assessing the FCS share in the paramagnetic shift, the degree of covalency in the metal-ligand bond can be gauged. Several methods to discriminate FCS and PCS have been used on the data of the nPrBTP- and C5-BPP-complexes and were evaluated regarding their applicability on lanthanide and actinide complexes with N-donor ligands. The study comprised the synthesis of all Ln(III) complexes with the exceptions of Pm(III) and Gd(III) as well as the Am(III) complex as a representative of the actinide series with both ligands. All complexes were fully characterised ({sup 1}H, {sup 13}C and {sup 15}N spectra) using NMR spectroscopy. By isotope enrichment with the NMR-active {sup 15}N in positions 8 and 9 in both ligands, resonance signals of these nitrogen atoms were detected for all complexes. The Bleaneymethod relies on different temperature dependencies for FCS (T{sup -1}) and PCS (T

Probing the coordination environment of Ti(3+) ions coordinated to nitrogen-containing Lewis bases.

Science.gov (United States)

Morra, E; Maurelli, S; Chiesa, M; Van Doorslaer, S

2015-08-28

Multi-frequency continuous-wave and pulsed EPR techniques are employed to investigate the coordination of nitrogen-containing ligands to Ti(3+)-chloro complexes. Frozen solutions of TiCl3 and TiCl3(Py)3 dissolved in nitrogen-containing solvents have been investigated together with the TiCl3(Py)3 solid-state complex. For these different systems, the hyperfine and nuclear quadrupole data of Ti(3+)-bound (14)N nuclei are reported and discussed in the light of DFT computations, allowing for a detailed description of the microscopic structure of these systems.

Solvent effect on thermodynamics of Ag(I) coordination to tripodal polypyridine ligands

DEFF Research Database (Denmark)

Del Piero, Silvia; Melchior, Andrea; Menotti, Davide

2009-01-01

  An investigation on the thermodynamics of complex formation between Ag(I) ion and different tripodal ligands (tris[(2-pyridyl)methyl]amine) (TPA) and 6,6'-bis[bis(2-pyridylmethyl)aminomethyl]-2,2'-bipyridine (BTPA) has been carried out in the aprotic solvents dimethylsulfoxide (DMSO) and dimeth......  An investigation on the thermodynamics of complex formation between Ag(I) ion and different tripodal ligands (tris[(2-pyridyl)methyl]amine) (TPA) and 6,6'-bis[bis(2-pyridylmethyl)aminomethyl]-2,2'-bipyridine (BTPA) has been carried out in the aprotic solvents dimethylsulfoxide (DMSO......)ethyl)amine  (Me3TREN) as a result of  combination of structural rigidity of TPA and lower s-donor ability of pyridinic moieties with respect to primary and secondary amines. The same trend is found if the stability of Ag(I) complex with TPA is compared with that of tris(2-(dimethylamino)ethyl)amine  (ME6TREN...... is largely influenced by the different solvational properties of the solvents towards Ag(I) ion rather than by the significative difference in the dielectric constants. Udgivelsesdato: Oktober...

Synthesis, physicochemical studies and biological evaluation of unimetallic and heterobimetallic complexes of hexadentate dihydrazone ligands

Directory of Open Access Journals (Sweden)

Fathy A. El Saied

2017-03-01

Full Text Available A new coordination unimetallic and heterobimetallic complexes of hexadentate N2O4 donor dihydrazone ligands were prepared by the condensation of 4-formyl antipyrine with adipic dihydrazide and succinic dihydrazide. The ligands (1 and (11 and their complexes thoroughly characterized using various analytical, physical and spectroscopic techniques, which indicate a distorted octahedral geometry around the metal ions. The ESR spectra of solid copper(II complexes (2–4 and (12–14 showed axial symmetry with g||>g⊥ > ge, indicating distorted octahedral structure and the presence of the unpaired electron in a d(x2−y2 orbital with significant covalent bond character. The antimicrobial activity results of the metal compounds (2–5, (7, (10, (12–15 and (17 show that, all these complexes exhibit inhibitory moderate to mild effects towards Bacillus subtilis, Escherichia coli and Aspergillus niger.

Photo- and electro-luminescence of rare earth doped ZnO electroluminors at liquid nitrogen temperature

International Nuclear Information System (INIS)

Bhushan, S.; Kaza, B.R.; Pandey, A.N.

1981-01-01

Photo (PL) and electroluminescent (EL) spectra of some rare earth (La, Gd, Er or Dy) doped ZnO electroluminors have been investigated at liquid nitrogen temperature (LNT) and compared with their corresponding results at room temperature (RT). In addition to three bands observed at RT, one more band on the higher wavelength side appears in EL spectra. Spectral shift with the exciting intensity at LNT supports the donor-acceptor (DA) model in which the rare earths form the donor levels. From the temperature dependent studies of PL and EL brightness, the EL phenomenon is found to be more susceptible to traps. (author)

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 1975-11-20 to 1975-12-09 (NODC Accession 7600702)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 1970-07-12 to 1972-11-04 (NODC Accession 7500783)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 1975-07-27 to 1975-09-05 (NODC Accession 7501077)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the South Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 1975-04-07 to 1975-04-19 (NODC Accession 7600703)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of...

Ligand Depot: a data warehouse for ligands bound to macromolecules.

Science.gov (United States)

Feng, Zukang; Chen, Li; Maddula, Himabindu; Akcan, Ozgur; Oughtred, Rose; Berman, Helen M; Westbrook, John

2004-09-01

Ligand Depot is an integrated data resource for finding information about small molecules bound to proteins and nucleic acids. The initial release (version 1.0, November, 2003) focuses on providing chemical and structural information for small molecules found as part of the structures deposited in the Protein Data Bank. Ligand Depot accepts keyword-based queries and also provides a graphical interface for performing chemical substructure searches. A wide variety of web resources that contain information on small molecules may also be accessed through Ligand Depot. Ligand Depot is available at http://ligand-depot.rutgers.edu/. Version 1.0 supports multiple operating systems including Windows, Unix, Linux and the Macintosh operating system. The current drawing tool works in Internet Explorer, Netscape and Mozilla on Windows, Unix and Linux.

Inter- and Intrapersonal Barriers to Living Donor Kidney Transplant among Black Recipients and Donors.

Science.gov (United States)

Davis, LaShara A; Grogan, Tracy M; Cox, Joy; Weng, Francis L

2017-08-01

End-stage renal disease (ESRD) is more common among Blacks, but Blacks are less likely to receive a live donor kidney transplant (LDKT). The objective of this study is to identify barriers and coping mechanisms that Black LDKT recipients and donors experienced while receiving or donating a kidney. A qualitative study was conducted using structured interviews. Thematic analysis was used for data interpretation. All 20 participants identified as Black, with two participants identifying themselves as multiracial. The mean age for the 14 recipients was 60, and the average age for the 6 living donors was 47. Themes emerging from the data suggest both recipients and donors faced barriers in the LDKT experience. Recipients faced barriers associated with their denial and avoidance of the severity of their ESRD, their desire to maintain the privacy of their health status, and their refusal to approach potential donors. Donors encountered negative responses from others about the donors' desire to donate and the initial refusal of recipients to accept a LDKT offer. Recipients identified faith as a coping mechanism, while donors identified normalization of donation as their method of coping. Various types of social support helped donors and recipients navigate the transplant process. Black LDKT recipients and donors must overcome barriers prior to receiving or donating a kidney. Most of these barriers arise from communication and interactions with others that are either lacking or undesirable. Future interventions to promote LDKT among Blacks may benefit by specifically targeting these barriers.

Alternative allogeneic donor sources for transplantation for childhood diseases: unrelated cord blood and haploidentical family donors.

Science.gov (United States)

Cairo, Mitchell S; Rocha, Vanderson; Gluckman, Eliane; Hale, Gregory; Wagner, John

2008-01-01

Allogeneic stem cell transplantation has been demonstrated to be curative in a wide variety of pediatric malignant and nonmalignant diseases, and can be traced back over 50 years ago to the original report of Thomas et al. HLA matched sibling donors have been the gold standard for pediatric recipients requiring allogeneic donors for both nonmalignant and malignant conditions. However, only 25% of potential pediatric recipients possesses an HLA-matched sibling donor, and the frequency is even less in those with genetic nonmalignant conditions because of genetically affected other siblings within the family. Therefore, 75% to 90% of potential pediatric recipients require alternative allogeneic donor cells for treatment of their underlying conditions. Potential alternative allogeneic donor sources include unrelated cord blood donors, unrelated adult donors, and haploidentical family donors. In this article we review the experience of both unrelated cord blood donor and haploidentical family donor transplants in selected pediatric malignant and nonmalignant conditions.

Donor-Derived Myeloid Sarcoma in Two Kidney Transplant Recipients from a Single Donor

Directory of Open Access Journals (Sweden)

Amudha Palanisamy

2015-01-01

Full Text Available We report the rare occurrence of donor-derived myeloid sarcoma in two kidney transplant patients who received organs from a single deceased donor. There was no evidence of preexisting hematologic malignancy in the donor at the time of organ recovery. Both recipients developed leukemic involvement that appeared to be limited to the transplanted organ. Fluorescence in situ hybridization (FISH and molecular genotyping analyses confirmed that the malignant cells were of donor origin in each patient. Allograft nephrectomy and immediate withdrawal of immunosuppression were performed in both cases; systemic chemotherapy was subsequently administered to one patient. Both recipients were in remission at least one year following the diagnosis of donor-derived myeloid sarcoma. These cases suggest that restoration of the immune system after withdrawal of immunosuppressive therapy and allograft nephrectomy may be sufficient to control HLA-mismatched donor-derived myeloid sarcoma without systemic involvement.

Energy status of pig donor organs after ischemia is independent of donor type.

Science.gov (United States)

Stadlbauer, Vanessa; Stiegler, Philipp; Taeubl, Philipp; Sereinigg, Michael; Puntschart, Andreas; Bradatsch, Andrea; Curcic, Pero; Seifert-Held, Thomas; Zmugg, Gerda; Stojakovic, Tatjana; Leopold, Barbara; Blattl, Daniela; Horki, Vera; Mayrhauser, Ursula; Wiederstein-Grasser, Iris; Leber, Bettina; Jürgens, Günther; Tscheliessnigg, Karlheinz; Hallström, Seth

2013-04-01

Literature is controversial whether organs from living donors have a better graft function than brain dead (BD) and non-heart-beating donor organs. Success of transplantation has been correlated with high-energy phosphate (HEP) contents of the graft. HEP contents in heart, liver, kidney, and pancreas from living, BD, and donation after cardiac death in a pig model (n=6 per donor type) were evaluated systematically. BD was induced under general anesthesia by inflating a balloon in the epidural space. Ten hours after confirmation, organs were retrieved. Cardiac arrest was induced by 9V direct current. After 10min of ventricular fibrillation without cardiac output, mechanical and medical reanimation was performed for 30min before organ retrieval. In living donors, organs were explanted immediately. Freeze-clamped biopsies were taken before perfusion with Celsior solution (heart) or University of Wisconsin solution (abdominal organs) in BD and living donors or with Histidine-Tryptophan-Ketoglutaric solution (all organs) in non-heart-beating donors, after perfusion, and after cold ischemia (4h for heart, 6h for liver and pancreas, and 12h for kidney). HEPs (adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, and phosphocreatine), xanthine, and hypoxanthine were measured by high-performance liquid chromatography. Energy charge and adenosine triphosphate-to-adenosine diphosphate ratio were calculated. After ischemia, organs from different donor types showed no difference in energy status. In all organs, a decrease of HEP and an increase in hypoxanthine contents were observed during perfusion and ischemia, irrespective of the donor type. Organs from BD or non-heart-beating donors do not differ from living donor organs in their energy status after average tolerable ischemia. Copyright © 2013 Elsevier Inc. All rights reserved.

Frequency and risk factors for donor reactions in an anonymous blood donor survey.

Science.gov (United States)

Goldman, Mindy; Osmond, Lori; Yi, Qi-Long; Cameron-Choi, Keltie; O'Brien, Sheila F

2013-09-01

Adverse donor reactions can result in injury and decrease the likelihood of donor return. Reaction reports captured in the blood center's database provide an incomplete picture of reaction rates and risk factors. We performed an anonymous survey, mailed to 40,000 donors in 2008, including questions about symptoms, height, weight, sex, and donation status. Reaction rates were compared to those recorded in our database. Possible risk factors were assessed for various reactions. The response rate was 45.5%. A total of 32% of first-time and 14% of repeat donors reported having any adverse symptom, most frequently bruising (84.9 per 1000 donors) or feeling faint or weak (66.2 per 1000). Faint reactions were two to eight times higher than reported in our database, although direct comparison was difficult. Younger age, female sex, and first-time donation status were risk factors for systemic and arm symptoms. In females, low estimated blood volume (EBV) was a risk factor for systemic symptoms. Only 51% of donors who consulted an outside physician also called Canadian Blood Services. A total of 10% of first-time donors with reactions found adverse effects information inadequate. This study allowed us to collect more information about adverse reactions, including minor symptoms and delayed reactions. Based on our findings of the risk factors and frequency of adverse reactions, we are implementing more stringent EBV criteria for younger donors and providing more detailed information to donors about possible adverse effects and their management. © 2012 American Association of Blood Banks.

Alternative Donor Graft Sources for Adults with Hematologic Malignancies: A Donor for All Patients in 2017!

Science.gov (United States)

Kindwall-Keller, Tamila L; Ballen, Karen K

2017-09-01

Hematopoietic stem cell transplant (HSCT) is potentially curative for a wide variety of malignant diseases, including acute and leukemias, lymphoma, and myelodysplasia. Choice of a stem cell donor is dependent on donor availability, donor compatibility and health, recipient disease type, and recipient condition. Current sources of stem cell donation for HSCT are matched sibling donors (MSDs), matched unrelated donors (MUDs), 1-antigen mismatched unrelated donors (MMUDs), haploidentical donors (haplo), and umbilical cord blood (UCB) units. Historically, preferred donors for HSCT have been human leukocyte antigen (HLA)-matched sibling donors; however, only about 30% of U.S. patients will have a MSD available. The majority of patients referred for HSCT will require an alternative donor graft: MUD, MMUD, UCB, or haplo. The likelihood of finding a MUD varies depending on the ethnicity of the recipient. White Caucasians of European descent have the greatest chance of finding a MUD. Chances of finding a MUD are significantly less for African-American or Hispanic recipients due to HLA polymorphisms. Therefore, MMUD, UCB, and haplo donor graft sources expand the donor pool for recipients who do not have a MSD or MUD available. Given the variety of different donor stem cell sources available today, nearly every patient who needs an allogeneic HSCT has a potential donor in 2017. All transplant-eligible patients with hematologic malignancies should be evaluated by a transplant center to determine if HSCT is a viable treatment option for their underlying disease process. The goal of this review is to increase the awareness of oncology practitioners to the availability of alternative donor stem cell transplants for patients with hematologic malignancies. Despite new agents, stem cell transplant remains the only curative therapy for many patients with acute and chronic leukemia, myelodysplasia, and lymphoma. Given the variety of different donor stem cell sources available today