WorldWideScience

Sample records for ps ii complex

  1. (II) complexes

    African Journals Online (AJOL)

    activities of Schiff base tin (II) complexes. Neelofar1 ... Conclusion: All synthesized Schiff bases and their Tin (II) complexes showed high antimicrobial and ...... Singh HL. Synthesis and characterization of tin (II) complexes of fluorinated Schiff bases derived from amino acids. Spectrochim Acta Part A: Molec Biomolec.

  2. Light-induced short-term adaptation mechanisms under redox control in the PS II-LHCII supercomplex: LHC II state transitions and PS II repair cycle

    Science.gov (United States)

    Kruse, Olaf

    2001-05-01

    Oxygenic photosynthesis takes place in the thylakoid membranes of cyanobacteria, algae and higher plants. While cyanobacteria have adapted to relatively constant environments, higher plants had to evolve mechanisms to adapt to continuous environmental changes. These include changes in light intensity, temperature and availability of water. One of the great challenges in plant cell biology is therefore to determine the regulatory mechanisms employed by higher plants and some algae to adapt to these constant environmental changes. The particular emphasis of this review is the description and characterisation of light-induced redox-controlled processes regulating the photosynthetic reactions, which involves maintaining maximal electron transport flow through the PS II-Cytb6f-PS I-FoF1ATPase electron transport chain and minimising light-induced oxidative damage to PS II which drives the highly oxidising water-splitting reaction. Two of the mechanisms involved in such short-term regulation processes are known as light harvesting complex II (LHC II) state transitions and photosystem II (PS II) repair cycle. They are followed by, and indeed may be a precondition in order to establish, the onset of the subsequent long-term mechanisms of regulation. In particular, the redox control of LHC II state transitions by reversible phosphorylation has been in the focus of many investigations, leading to many new results demonstrating the complexity of thylakoid-associated redox control mechanisms.

  3. New safety training for access to the PS complex areas

    CERN Multimedia

    2012-01-01

    Since 10/08/2012, a new course dedicated to the specific radiological risks in the accelerators of the PS complex has been available on SIR (https://sir.cern.ch/). This course complements the general classroom-based Radiation Safety training. Successful completion of the course will be obligatory and verified by the access system as from 01/11/2012 for access to the following accelerator areas: LINAC2, BOOSTER, PS and TT2. Information and reminder e-mails will be sent to all persons currently authorized to access the accelerators of the PS complex. For questions please contact the HSE unit and in particular, the Radiation Protection Group (+41227672504 or safety-rp-ps-complex@cern.ch).

  4. Beam Quality Preservation in the CERN PS-SPS Complex

    CERN Multimedia

    Arduini, Gianluigi

    2004-01-01

    The LHC will require beams of unprecedented transverse and longitudinal brightness. Their production imposes tight constraints on the emittance growth in each element of the LHC injector chain, namely the PS-SPS Accelerator Complex. The problems encountered at the different stages of the acceleration in the complex span a wide range of topics, such as injection matching, RF gymnastics, space charge, transverse and longitudinal single- and coupled-bunch instabilities, and electron cloud effects. The measurement techniques developed and applied to identify and study the various sources of emittance dilution to the high precision required for the LHC beams and the solutions found to control such phenomena are illustrated.

  5. An Antiproton Decelerator in the CERN PS Complex

    CERN Document Server

    Riunaud, J P; Baird, S A; Boillot, J; Bosser, Jacques; Brouet, M; Caspers, Friedhelm; Chanel, M; Chohan, V; Eriksson, T; Garoby, R; Giannini, R; Giovannozzi, Massimo; Gruber, J; Hémery, J Y; Koziol, Heribert; MacCaferri, R; Maury, S; Metzmacher, K D; Möhl, D; Mulder, H; Pedersen, F; Perriollat, F; Poncet, Alain; Riunaud, J P; Serre, C; Simon, Daniel Jean; Tranquille, G; Tuyn, Jan Willem Nicolaas; Williams, B; Williams, D J

    1996-01-01

    The present CERN PS low-energy antiproton complex involves 4 machines to collect, cool, decelerate and supply experiments with up to 1010 antiprotons per pulse and per hour of momenta ranging from 0.1 to 2 GeV/c. In view of a possible future physics programme requiring low energy antiprotons, mainly to carry out studies on antihydrogen, a simplified scheme providing at low cost antiprotons at 100 MeV/c has been studied. It requires only one machine, the present Antiproton Collector (AC) converted into a cooler and decelerator (Antiproton Decelerator, AD) and delivering beam to experiments in the hall of the present Antiproton Accumulator Complex (AAC) [1]. This paper describes the feasibility study of such a scheme [2].

  6. The PS complex produces the nominal LHC beam

    CERN Document Server

    Benedikt, Michael; Borburgh, J; Cappi, R; Chanel, M; Chohan, V; Cyvoct, G; Garoby, R; Grier, D G; Gruber, J; Hancock, S; Hill, C E; Jensen, E; Krusche, A; Lindroos, M; Métral, Elias; Métral, G; Metzmacher, K D; Olsfors, J; Pedersen, F; Raich, U; Riunaud, J P; Royer, J P; Sassowsky, M; Schindl, Karlheinz; Schönauer, Horst Otto; Thivent, M; Ullrich, H M; Völker, F V; Vretenar, Maurizio; Barnes, M; Blackmore, E W; Cifarelli, F; Clark, G; Jones, F; Koscielniak, Shane Rupert; Mammarella, F; Mitra, A; Poirier, R; Reiniger, K W; Ries, T C

    2000-01-01

    The LHC [1] will be supplied, via the SPS, with protons from the pre-injector chain comprising Linac2, PS Booster (PSB) and PS. These accelerators have under-gone a major upgrading programme [2] during the last five years so as to meet the stringent requirements of the LHC. These imply that many high-intensity bunches of small emittance and tight spacing (25 ns) be available at the PS extraction energy (25 GeV). The upgrading project involved an increase of Linac2 current, new RF systems in the PSB and the PS, raising the PSB energy from 1 to 1.4 GeV, two-batch filling of the PS and the installation of high-resolution beam profile measurement devices. With the project entering its final phase and most of the newly installed hardware now being operational, the emphasis switches to producing the nominal LHC beam and tackling the associated beam physics problems. While a beam with transverse characteristics better than nominal has been obtained, the longitudinal density still needs to be increased. An alternativ...

  7. Complex variables II essentials

    CERN Document Server

    Solomon, Alan D

    2013-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Complex Variables II includes elementary mappings and Mobius transformation, mappings by general functions, conformal mappings and harmonic functions, applying complex functions to a

  8. (ii) and ni (ii) complexes with n

    African Journals Online (AJOL)

    DR. AMINU

    II) complexes with a. Schiff base derived from. 4-dimetylamino benzaldehyde and primary amines. The chemical analysis data showed the formation of (1:1) metal - ligand ratio and a square planar geometry was suggested for Co(II) and Ni(II) ...

  9. Copper (II) Complex

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

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

  10. Catalytic property of TiO2/PS complex nanoparticles prepared via a ...

    Indian Academy of Sciences (India)

    Abstract. With an average size of 7 nm and good catalytic property under the natural light, TiO2/PS complex nanoparticles were successfully prepared through a novel two-step method (TSM) from TiCl4, used as both the catalyst for polymerization of styrene and Ti source, and styrene monomer and characterized by TG-DTA ...

  11. Copper (II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

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

  12. TETRACYANONICKELATE(II) PYRIDAZINE COMPLEXES

    African Journals Online (AJOL)

    B. S. Chandravanshi

    and their structures consist of polymeric layers of │M−Ni(CN)4│∞ with the pdz bound to the metal (M) atom. KEY WORDS: Hofmann-type complexes, Vibrational spectra, Pyridazine, Tetracyanonickelate(II), Thermal analysis. INTRODUCTION. Cyano-bridged complexes have been shown to form polymeric structures by ...

  13. Risk Management Capability Maturity and Performance of Complex Product and System (CoPS Projects with an Asian Perspective

    Directory of Open Access Journals (Sweden)

    Ren, Y.

    2014-07-01

    Full Text Available Complex Products and Systems (CoPS are high value, technology and engineering-intensive capital goods. The motivation of this study is the persistent high failure rate of CoPS projects, Asian CoPS provider’s weak capability and lack of specific research on CoPS risk management. This paper evaluates risk management maturity level of CoPS projects against a general CoPS risk management capability maturity model (RM-CMM developed by the authors. An Asian based survey was conducted to investigate the value of RM to project performance, and Asian (non-Japanese CoPS implementers’ perceived application of RM practices, their strengths and weaknesses. The survey result shows that higher RM maturity level leads to higher CoPS project performance. It also shows project complexity and uncertainty moderates the relationship between some RM practices and project performance, which implies that a contingency approach should be adopted to manage CoPS risks effectively. In addition, it shows that Asian CoPS implementers are weak in RM process and there are also rooms for improvement in the softer aspects of organizational capabilities and robustness.

  14. New layered tin(II) thiophosphates ASnPS4 (A = K, Rb, Cs): synthesis, structure, glass formation, and the modulated CsSnPS4.

    Science.gov (United States)

    Banerjee, Santanu; Malliakas, Christos D; Kanatzidis, Mercouri G

    2012-11-05

    The layered compounds KSnPS(4) (1), RbSnPS(4) (2), and CsSnPS(4) (3) were synthesized using the chalcophosphate flux technique at high temperature and are rare examples of divalent Sn(II) thiophosphates. Orange polyhedral crystals of compound 1 crystallize in the monoclinic space group P2(1)/c with a = 6.6673(13) Å, b = 11.9697(24) Å, c = 8.7604(18), and β=127.347(8)° in a 2-dimensional layered structure. Compound 2 is isostructural to 1. Yellow block shaped crystals of compound 3 crystallize in the monoclinic superspace group P2(1)(αβ0)0 with a commensurate q-vector at 1/4a* + 1/4c* with a = 18.0477(14) Å, b = 6.2021(5) Å, and c = 6.8415(5) Å. The structure of all three compounds contains SnS(3) pyramids, which is an extremely rare solid state chalcogenide coordination environment. All three compounds are semiconductors having well-defined band-gaps between 2.0 and 2.2 eV. The compounds are congruently melting and can be obtained as glasses by rapid quenching of the melt, which subsequently crystallize upon heating.

  15. binuclear copper(II) complexes

    Indian Academy of Sciences (India)

    Administrator

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

  16. Femtosecond spectroscopy of the dithiolate Cu(II) and Ni(II) complexes.

    Science.gov (United States)

    Plyusnin, Victor F; Pozdnyakov, Ivan P; Grivin, Vjacheslav P; Solovyev, Aleksey I; Lemmetyinen, Helge; Tkachenko, Nikolai V; Larionov, Stanislav V

    2014-12-21

    Femtosecond spectroscopy was applied to study the ultrafast dynamics for the excited states of dithiolate Cu(ii) and Ni(ii) complexes. The detailed information on the initial steps after the absorption of a photon by the metal complexes is of fundamental importance to understand the mechanism of photochemical reactions. The fast processes for the dithiolate complexes have hardly been studied. In this review the spectra of transients and their lifetimes will be presented. For example, the xanthogenate Ni(S2COEt)2 complex in acetonitrile and CCl4 after the pulse of the second harmonic (100 fs, 400 nm) of a Ti:S laser moves to the excited (1)LMCT state which decays in 0.76 ps to the excited (3)LF state. In 6.8 ps the (3)LF state undergoes vibrational cooling and then it slowly decays in 550 ps to the ground state. However, for many dithiolate complexes the kinetic curves can be well treated in a two-exponential approximation. A short time (less than 1 ps) may include several processes (relaxation of the Franck-Condon state, redistribution of vibrational energy (IVR), internal conversion (IC) and intersystem crossing (ISC)). A long time (a few picoseconds) usually reflects the vibrational cooling of the ground state. The quantum yields of the dithiolate and dithiolene complex disappearance in halogen containing solvents have a strong dependence on the wavelength of irradiation. It is very likely that electron transfer to the acceptor becomes effective when the electron in the excited complex moves to antibonding ligand orbitals localized at the periphery of the complex close to the acceptor molecule (halogenated solvent).

  17. Preparation and Antimicrobial Screeningof Cu (II, Ni (II, Zn (II Cd (II Complexes

    Directory of Open Access Journals (Sweden)

    R. M. Desai

    2006-01-01

    Full Text Available The metal complexes of Ni(II, Cu(II, Zn(II Cd(II with organic ligands viz Hydrazine hydrate, 1,2-N,N'-Bisammonium thiocarbamoyl ethane and 1,4-N,N'-Bisammonium thiocarbamoyl benzene have been prepared. These ligands and metal complexes of dithiocarbamates were screened for their antimicrobial activity against various microbs.

  18. Model based, detailed fault analysis in the CERN PS complex equipment

    CERN Document Server

    Beharrell, M; Bouché, J M; Cupérus, J; Lelaizant, M; Mérard, L

    1995-01-01

    In the CERN PS Complex of accelerators, about a thousand of equipment of various type (power converters, RF cavities, beam measurement devices, vacuum systems etc...) are controlled using the so-called Control Protocol, already described in previous Conferences. This Protocol, a model based equipment access standard, provides, amongst other facilities, a uniform and structured fault description and report feature. The faults are organized in categories, following their gravity, and are presented at two levels: the first level is global and identical for all devices, the second level is very detailed and adapted to the peculiarities of each single device. All the relevant information is provided by the equipment specialists and is appropriately stored in static and real time data bases; in this way a unique set of data driven application programs can always cope with existing and newly added equipment. Two classes of applications have been implemented, the first one is intended for control room alarm purposes,...

  19. A rule-based consultant for accelerator beam scheduling used in the CERN PS complex

    CERN Document Server

    Lewis, J; Varga, L Z

    1995-01-01

    The CERN PS accelerator complex consists of nine interacting accelerators which work together to produce particle beams for different end users, varying in particle type, energy, time structure, and geometry. The beam production schedule is time sliced, and depends on the current operational requirements, and dynamically on the accelerator status, so that production schedule changes occur in real time. Many potential schedules are not valid due to various system constraints and these constraints vary over time as new operational modes are introduced. In order to ensure that only valid schedules are given to the complex, an automated tool has been developed to indicate whether a potential schedule is valid or not. This presentation describes the method by which the validity of a beam schedule is determined and how this method was implemented using a rule-based approach based on SQL, avoiding the use of an expert system shell. Both the data to instantiate the rules and the rules themselves are kept in an Oracle...

  20. Photocleavage of DNA by copper (II) complexes

    Indian Academy of Sciences (India)

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

  1. metal complexes of copper(ii)

    African Journals Online (AJOL)

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

  2. The coat protein complex II, COPII, protein Sec13 directly interacts with presenilin-1

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Anders Lade, E-mail: aln@humgen.au.dk [Department of Human Genetics, The Bartholin Building, University of Aarhus, DK-8000 Aarhus C (Denmark)

    2009-10-23

    Mutations in the human gene encoding presenilin-1, PS1, account for most cases of early-onset familial Alzheimer's disease. PS1 has nine transmembrane domains and a large loop orientated towards the cytoplasm. PS1 locates to cellular compartments as endoplasmic reticulum (ER), Golgi apparatus, vesicular structures, and plasma membrane, and is an integral member of {gamma}-secretase, a protein protease complex with specificity for intra-membranous cleavage of substrates such as {beta}-amyloid precursor protein. Here, an interaction between PS1 and the Sec13 protein is described. Sec13 takes part in coat protein complex II, COPII, vesicular trafficking, nuclear pore function, and ER directed protein sequestering and degradation control. The interaction maps to the N-terminal part of the large hydrophilic PS1 loop and the first of the six WD40-repeats present in Sec13. The identified Sec13 interaction to PS1 is a new candidate interaction for linking PS1 to secretory and protein degrading vesicular circuits.

  3. Isolation and biological activities of an antineoplastic protein-polysaccharide complex (PS4A) obtained from Mycobacterium vaccae.

    Science.gov (United States)

    Tian, X X; Li, A; Zhou, W; Farrugia, I V; Groves, M J

    1999-01-01

    A mixture of water-soluble protein-polysaccharides (PS4A) was isolated by boiling intact cells of Mycobacterium vaccae, a fast growing mycobacterium. Sephadex G-75 column chromatography of the crude extract separated the biologically active high molecular weight (> 50 kDa) fraction (in the void volume) from the low molecular weight degradation products. Compositional analysis demonstrated that PS4A contained protein and polysaccharide in a ratio of approximately 1.5 to 1, but no lipids were detected. The antineoplastic activity was tested in vivo by a S-180 murine sarcoma model using female CFW mice. The immunostimulating activity was tested in vitro using murine peritoneal macrophages isolated from BALB/C mice. The results demonstrated that PS4A significantly decreased tumor incidence in vivo and produced activation of murine peritoneal macrophages. However, the antineoplastic activity was only attributable to the high molecular weight fraction of the protein-polysaccharide complex. The low molecular weight fraction had no antineoplastic activity in vivo despite stimulation of TNF-alpha production in vitro. In vitro experiments also demonstrated that although all PS4A components significantly increased TNF-alpha production by macrophages, the high molecular weight fraction stimulated more IL-1 production, indicating a better immunostimulating activity.

  4. [PS II photochemical efficiency in flag leaf of wheat varieties and its adaptation to strong sun- light intensity on farmland of Xiangride in Qinghai Province, Northwest China].

    Science.gov (United States)

    Shi, Sheng-Bo; Chen, Wen-Jie; Shi, Rui; Li, Miao; Zhang, Huai-Gang; Sun, Ya-Nan

    2014-09-01

    Taking four wheat varieties developed by Northwest Institute of Plateau Biology, Chinese Academy of Sciences, as test materials, with the measurement of content of photosynthetic pigments, leaf area, fresh and dry mass of flag leaf, the PS II photochemistry efficiency of abaxial and adaxial surface of flag leaf and its adaptation to strong solar radiation during the period of heading stage in Xiangride region were investigated with the pulse-modulated in-vivo chlorophyll fluorescence technique. The results indicated that flag leaf angle mainly grew in horizontal state in Gaoyuan 314, Gaoyuan 363 and Gaoyuan 584, and mainly in vertical state in Gaoyuan 913 because of its smaller leaf area and larger width. Photosynthetic pigments were different among the 4 varieties, and positively correlated with intrinsic PS II photochemistry efficiencies (Fv/Fm). In clear days, especially at noon, the photosynthetic photoinhibition was more serious in abaxial surface of flag leaf due to directly facing the solar radiation, but it could recover after reduction of sunlight intensity in the afternoon, which meant that no inactive damage happened in PS II reaction centers. There were significant differences of PS II actual and maximum photochemical efficiencies at the actinic light intensity (ΦPS II and Fv'/Fm') between abaxial and adaxial surface, and their relative variation trends were on the contrary. The photochemical and non-photochemical quenching coefficients (qP and NPQ) had a similar tendency in both abaxial and adaxial surfaces. Although ΦPS II and qP were lower in adaxial surface of flag leaf, the Fv'/Fm' was significantly higher, which indicated that the potential PS II capture efficiency of excited energy was higher. The results demonstrated that process of photochemical and non-photochemical quenching could effectively dissipate excited energy caused by strong solar radiation, and there were higher adaptation capacities in wheat varieties natively cultivated in

  5. [Effects of NO3- stress on photosynthetic rate, photochemical efficiency of PS II and light energy allocation in cucumber seedling leaves].

    Science.gov (United States)

    Su, Xiu-Rong; Wang, Xiu-Feng; Yang, Feng-Juan; Wei, Min

    2007-07-01

    This paper studied the effects of different NO3- concentration on the photosynthetic rate, photochemical efficiency, and absorbed light energy allocation in cucumber seedling leaves. The results indicated that when the available NO3- concentration in the medium was low (14-98 mmol NO3- x L(-1)), an appropriate supplement of NO3- could enhance the capability of cucumber leaves in capturing light energy, and promote the photosynthesis. However, with further increase of NO3-, the photochemical efficiency of PS II decreased, electron transfer restrained, and net photosynthetic rate as well as the absorbed light energy used in photochemical reaction of PS II decreased. At the same time, the light energy used in antenna heat dissipation increased, while the photochemical efficiency decreased. After treated with 140 and 182 mmol NO3- x L(-1) for 6 days, the photosynthetic rate (P(n)) was decreased by 35% and 78%, respectively, maximal PS II efficiency at open centers in the absence of NPQ (F(v)/F(m)), antenna efficiency at open centers in the presence of NPQ (F(v)'/F(m)'), actual PS II efficiency (phi (PSII ) and photochemical quenching (q(P)) were lower, non-photochemical quenching (NPQ) was higher, and the deviation from full balance between PS I and PS II (beta/alpha - 1) was improved significantly, compared with the control. The fluctuant ranges of these chlorophyll fluorescence parameters were increased at higher NO3- concentration, compared with those at lower NO3- concentration. The absorbed light energy allocated to the photochemical reaction of PS II (P) was reduced by high light intensity and high NO3- concentration. Meanwhile, the proportion allocated in antenna heat dissipation (D) increased significantly. Antenna heat dissipation was the main way for excessive energy dissipation.

  6. META II Complexity and Adaptability

    Science.gov (United States)

    2011-08-01

    59  27. Design 2 – Bevel Pair...members also included Dr. David Corman, Dr. Sabyasachi Basu, Dr. Rainer Romatka, Dr. Gregory Robel, Ron Howard, Tom Herm, Patrick Goertzen, James Meany...complexity. Advantages all the gears are either Spur or equivalent of a spur gear it is easy to Design and manufacture compared to the Bevel -Spur

  7. Cyclometallated ruthenium (II) carbonyl complexes with 1 ...

    Indian Academy of Sciences (India)

    A facile method for the synthesis of a series of cyclometallated ruthenium(II) carbonyl complexes with 1-pyrenaldehyde 4-R-3-thiosemicarbazones (H2Ln where the two H's represent the dissociable thioamide and pyrenyl protons; R = H, Me and Ph) has been described. The characterization of the complexes having the ...

  8. Cu (II), Zn (II) andMn (II) complexes of poly (methyl vinyl ether-alt ...

    Indian Academy of Sciences (India)

    MVE-alt-MA)) with Zn(II), Mn(II) and Cu(II) ions were synthesized from the reaction of the aqueous solution of copolymer and metal(II) chlorides at different temperatures ranging from 25° to 40°C. Elemental analysis of themetal-polymer complexes ...

  9. Spectrophotometric study of Co(II, Ni(II, Cu(II, Zn(II, Pd(II and Hg(II complexes with isatin- β-thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    SANDRA S. KONSTANTINOVIC

    2007-10-01

    Full Text Available The composition and stability of the complexes of isatin-b-thiosemicarba­zone with Co(II, Ni(II, Cu(II, Zn(II, Pd(II and Hg(II have been investigated us­ing spectrophotometric method at 30 °C and constant ionic strength of 0.1 mol dm-3 (KNO3 in 70 % ethanol. Experimental results indicate the formation of MeL and MeL2 complexes for Ni(II and Co(II, and MeL for Cu(II, Zn(II, Pd(II and Hg(II complexes, whose stability constants, bn, have been calculated using a com­puteri­zed iterative method of successive approximation.

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

    Indian Academy of Sciences (India)

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

  11. A low-spin Fe(III) complex with 100-ps ligand-to-metal charge transfer photoluminescence

    Science.gov (United States)

    Chábera, Pavel; Liu, Yizhu; Prakash, Om; Thyrhaug, Erling; Nahhas, Amal El; Honarfar, Alireza; Essén, Sofia; Fredin, Lisa A.; Harlang, Tobias C. B.; Kjær, Kasper S.; Handrup, Karsten; Ericson, Fredric; Tatsuno, Hideyuki; Morgan, Kelsey; Schnadt, Joachim; Häggström, Lennart; Ericsson, Tore; Sobkowiak, Adam; Lidin, Sven; Huang, Ping; Styring, Stenbjörn; Uhlig, Jens; Bendix, Jesper; Lomoth, Reiner; Sundström, Villy; Persson, Petter; Wärnmark, Kenneth

    2017-03-01

    Transition-metal complexes are used as photosensitizers, in light-emitting diodes, for biosensing and in photocatalysis. A key feature in these applications is excitation from the ground state to a charge-transfer state; the long charge-transfer-state lifetimes typical for complexes of ruthenium and other precious metals are often essential to ensure high performance. There is much interest in replacing these scarce elements with Earth-abundant metals, with iron and copper being particularly attractive owing to their low cost and non-toxicity. But despite the exploration of innovative molecular designs, it remains a formidable scientific challenge to access Earth-abundant transition-metal complexes with long-lived charge-transfer excited states. No known iron complexes are considered photoluminescent at room temperature, and their rapid excited-state deactivation precludes their use as photosensitizers. Here we present the iron complex [Fe(btz)3]3+ (where btz is 3,3‧-dimethyl-1,1‧-bis(p-tolyl)-4,4‧-bis(1,2,3-triazol-5-ylidene)), and show that the superior σ-donor and π-acceptor electron properties of the ligand stabilize the excited state sufficiently to realize a long charge-transfer lifetime of 100 picoseconds (ps) and room-temperature photoluminescence. This species is a low-spin Fe(III) d5 complex, and emission occurs from a long-lived doublet ligand-to-metal charge-transfer (2LMCT) state that is rarely seen for transition-metal complexes. The absence of intersystem crossing, which often gives rise to large excited-state energy losses in transition-metal complexes, enables the observation of spin-allowed emission directly to the ground state and could be exploited as an increased driving force in photochemical reactions on surfaces. These findings suggest that appropriate design strategies can deliver new iron-based materials for use as light emitters and photosensitizers.

  12. FORMATION OF BINARY COMPLEXES OF Co(II), Ni(II) AND Cu(II ...

    African Journals Online (AJOL)

    Preferred Customer

    binary complex systems contain the chemical species ML, ML2, MLH, ML2H and ML2H2 for Co(II), Ni(II) and. Cu(II) in dioxan-water ... KEY WORDS: Binary species, Stability constants, Metal, Dopa, Dioxan, pH-metry ..... application in complex equilibria to decide whether inclusion of more species in the model is necessary ...

  13. Biologically active new Fe(II, Co(II, Ni(II, Cu(II, Zn(II and Cd(II complexes of N-(2-thienylmethylenemethanamine

    Directory of Open Access Journals (Sweden)

    C. SPÎNU

    2008-04-01

    Full Text Available Iron(II, cobalt(II, nickel (II, copper (II, zinc(II and cadmium(II complexes of the type ML2Cl2, where M is a metal and L is the Schiff base N-(2-thienylmethylenemethanamine (TNAM formed by the condensation of 2-thiophenecarboxaldehyde and methylamine, were prepared and characterized by elemental analysis as well as magnetic and spectroscopic measurements. The elemental analyses suggest the stoichiometry to be 1:2 (metal:ligand. Magnetic susceptibility data coupled with electronic, ESR and Mössbauer spectra suggest a distorted octahedral structure for the Fe(II, Co(II and Ni(II complexes, a square-planar geometry for the Cu(II compound and a tetrahedral geometry for the Zn(II and Cd(II complexes. The infrared and NMR spectra of the complexes agree with co-ordination to the central metal atom through nitrogen and sulphur atoms. Conductance measurements suggest the non-electrolytic nature of the complexes, except for the Cu(II, Zn(II and Cd(II complexes, which are 1:2 electrolytes. The Schiff base and its metal chelates were screened for their biological activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the metal chelates were found to possess better antibacterial activity than that of the uncomplexed Schiff base.

  14. Studies on femtosecond fluorescence dynamics of photosystem II Particle complex at low temperature

    CERN Document Server

    Liu Xiao; He, Jun Fang; Cai, Xia; Peng Jun Fang; Kuang Ting Yun

    2004-01-01

    In order to understanding the diversity of energy transfer in PS II at different temperatures, PS II particle complex purified from spinach was investigated with femtosecond time-resolved fluorescence spectroscopy in the case of excitation 507 nm at 83 K, 160 K, 273 K. The data were analyzed by Gauss analysis and fluorescence decay time- fitting. Some results were achieved. (1) Increase of the temperature results in a broadening of the fluorescence emission spectra due to the temperature-dependent expressions for nonradiative transitions between two electronic states. (2) There are at least several characteristic Chl molecules exist in PS II particle complex, i.e. Chl b/sub 639//sup 640/, Chl b/sub 640//sup 645/, Chl a/sub 660//sup 663/, Chl a/sub 667//sup 668/, Chl a/sub 673//sup 676/, Chl a/sub 680 //sup 681/, Chl a/sub 680/681//sup 682/, Chl a/sub 684,685//sup 668 /689/, Chl a/sub 688//sup 698/, (Chl a/b/sub a//sup e/: a represents the peak of absorption, e represents the peak of emission). (3) Though the ...

  15. GSK3 beta forms a tetrameric complex with endogenous PS1-CTF/NTF and beta-catenin. Effects of the D257/D385A and FAD-linked mutations.

    Science.gov (United States)

    Tesco, G; Tanzi, R E

    2000-01-01

    We have previously shown that the endogenous C-terminal fragment of presenilin 1 co-immunoprecipitates with endogenous beta-catenin. Since PS1 has been suggested to be involved in beta-catenin stabilization, we further investigated whether GSK3 beta, responsible for beta-catenin phosphorylation and degradation, is part of the PS1/beta-catenin complex. In naïve H4 and CHO cells, PS1 co-immunoprecipitated with both endogenous beta-catenin and GSK3 beta. In addition, GSK3 beta endogenously binds to the PS1-CTF/NTF complex and beta-catenin in naïve CHO cells. GSK3 beta also co-immunoprecipitated with PS1 full length in CHO cell lines overexpressing PS1 wild type. Given that it has been recently shown that PS1 mutations of aspartate 257 or 385 result in prevention of PS1 endoproteolysis and inhibition of gamma-secretase activity, we also tested whether PS1 endoproteolysis is required for beta-catenin/GSK3 beta/PS1 binding and whether PS1 FAD-linked mutations affect GSK3 beta recruitment in the PS1/beta-catenin complex. GSK3 beta was detected in PS1 immunoprecipitates from H4 cell lines overexpressing PS1 wild type, delta E10, A286E, L246V and in CHO cell lines overexpressing aspartate or M146L mutations. The latter data show that the absence of PS1 endoproteolysis (D257A/D385A and delta E10) or the presence of PS1-FAD mutations does not interfere with beta-catenin/GSK3 beta/PS1 complex formation.

  16. ANTIMICROBIAL ACTIVITY OF COPPER(II COMPLEXES

    Directory of Open Access Journals (Sweden)

    Andrea Čongrádyová

    2014-02-01

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

  17. Systems approach to excitation-energy and electron transfer reaction networks in photosystem II complex: model studies for chlorophyll a fluorescence induction kinetics.

    Science.gov (United States)

    Matsuoka, Takeshi; Tanaka, Shigenori; Ebina, Kuniyoshi

    2015-09-07

    Photosystem II (PS II) is a protein complex which evolves oxygen and drives charge separation for photosynthesis employing electron and excitation-energy transfer processes over a wide timescale range from picoseconds to milliseconds. While the fluorescence emitted by the antenna pigments of this complex is known as an important indicator of the activity of photosynthesis, its interpretation was difficult because of the complexity of PS II. In this study, an extensive kinetic model which describes the complex and multi-timescale characteristics of PS II is analyzed through the use of the hierarchical coarse-graining method proposed in the authors׳ earlier work. In this coarse-grained analysis, the reaction center (RC) is described by two states, open and closed RCs, both of which consist of oxidized and neutral special pairs being in quasi-equilibrium states. Besides, the PS II model at millisecond scale with three-state RC, which was studied previously, could be derived by suitably adjusting the kinetic parameters of electron transfer between tyrosine and RC. Our novel coarse-grained model of PS II can appropriately explain the light-intensity dependent change of the characteristic patterns of fluorescence induction kinetics from O-J-I-P, which shows two inflection points, J and I, between initial point O and peak point P, to O-J-D-I-P, which shows a dip D between J and I inflection points. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The importance of a highly active and DeltapH-regulated diatoxanthin epoxidase for the regulation of the PS II antenna function in diadinoxanthin cycle containing algae.

    Science.gov (United States)

    Goss, Reimund; Ann Pinto, Elizabeth; Wilhelm, Christian; Richter, Michael

    2006-10-01

    The present study focuses on the regulation of diatoxanthin (Dtx) epoxidation in the diadinoxanthin (Ddx) cycle containing algae Phaeodactylum tricornutum, Thalassiosira pseudonana, Cyclotella meneghiniana and Prymnesium parvum and its significance for the control of the photosystem II (PS II) antenna function. Our data show that Dtx epoxidase can exhibit extremely high activities when algal cells are transferred from high light (HL) to low light (LL). Under HL conditions, Dtx epoxidation is strongly inhibited by the light-driven proton gradient. Uncoupling of the cells during HL illumination restores the high epoxidation rates observed during LL. In Ddx cycle containing algae, non-photochemical quenching of chlorophyll fluorescence (NPQ) is directly correlated with the Dtx concentration and independent of the presence of the proton gradient. This means that a fast conversion of PS II from the heat dissipating state back to the light-harvesting state can only be realized by an efficient removal of the quenching pigment Dtx. It is proposed that the high Dtx epoxidation rates during LL illumination serve exactly this purpose. The inhibition of Dtx epoxidation by the DeltapH, on the other hand, ensures rapid increases in the Dtx concentration when photoprotection under conditions of HL illumination is required. The regulation of the PS II antenna function in Ddx cycle containing algae is different to that in violaxanthin (Vx) cycle containing plants, where for the zeaxanthin (Zx)-dependent NPQ the presence of a proton gradient is mandatory. In the green alga Chlorella vulgaris conversion of PS II from the heat dissipating state back to the light-harvesting state is controlled by the DeltapH, whose relaxation after a transition from HL to darkness or LL rapidly abolishes the thermal dissipation of excitation energy, including the Zx-dependent NPQ. Due to the inability of Zx to quench fluorescence in the absence of the DeltapH a fast epoxidation of Zx to Vx in LL is not

  19. Spectroscopy of Bioactive Manganese(II) and Copper(II) Complexes with Mannich Bases

    Science.gov (United States)

    Harbatsevich, H. I.; Loginova, N. V.; Koval‧chuk, T. V.; Osipovich, N. P.; Gres, A. T.; Azarko, I. I.; Polozov, G. I.

    2015-11-01

    The compositions and geometries of coordination polyhedra in Cu(II) and Mn(II) complexes with Mannich bases were determined using IR, EPR, and electron spectroscopy. It was shown that bidentate ligands were coordinated to the metal ions in these complexes. The coordination polyhedra of mononuclear Cu(II) and Mn(II) complexes consisted of two mono-anionic ligands. Polyhedra of the Mn(II) complexes also contained two water molecules. The Cu(II) complexes had characteristic square-planar [CuN2O2] coordination polyhedra; Mn(II) complexes, [MnN2O4] octahedra.

  20. Single Crystal X- and Q-Band EPR Spectroscopy of a Binuclear Mn2(III,IV) Complex Relevant to the Oxygen-Evolving Complex of Photosystem II

    OpenAIRE

    Yano, Junko; Sauer, Kenneth; Girerd, Jean-Jacques; Yachandra, Vittal K.

    2004-01-01

    The anisotropic g and hyperfine tensors of the Mn di-μ-oxo complex, [Mn2(III,IV)O2(phen)4](PF6)3·CH3CN, were derived by single-crystal EPR measurements at X- and Q-band frequencies. This is the first simulation of EPR parameters from single-crystal EPR spectra for multinuclear Mn complexes, which are of importance in several metalloenzymes; one of them is the oxygen-evolving complex in photosystem II (PS II). Single-crystal [Mn2(III,IV)O2(phen)4](PF6)3·CH3CN EPR spectra showed distinct resolv...

  1. STABILITY OF BINARY COMPLEXES OF Pb(II), Cd(II) AND Hg(II ...

    African Journals Online (AJOL)

    Preferred Customer

    Binary complexes of maleic acid with toxic metal ions such as Pb(II), Cd(II) and Hg(II) have been studied in 0.0-2.5% v/v .... refinement of binary systems, the correction factor and the protonation constants of maleic acid were fixed. .... In order to rely upon the 'best-fit' model for critical evaluation and application under varied.

  2. Copper (II), cobalt (II), nickel (II) and zinc (II) complexes of Schiff ...

    Indian Academy of Sciences (India)

    Abstract. New Schiff base chelates of Cu(II), Co(II), Ni(II) and Zn(II) derived from benzil-2,4-dinitrophenylhydrazone with aniline have been synthesised. Microanalytical data, molar conductance, and magnetic susceptibility values have been obtained, and IR, 1H NMR, 13C NMR, UV-Vis, CV and EPR spectral studies have ...

  3. Optical dephasing in the light-harvesting complex II A two-pulse photon echo study

    CERN Document Server

    Hillmann, F; Redlin, H; Renger, G; Voigt, J

    2001-01-01

    Time-resolved and integrated two-pulse photon echo signals were measured at 5 K in the wavelength range from 640 to 690 nm (with an increment of 5 nm) in samples of solubilized light-harvesting complex II (LHC II) from spinach. Furthermore, the dephasing time was determined at 680 nm in the temperature range 5 less than approximately equals T less than approximately equals 300 K. The following results and conclusions were gathered from these experiments: (a) the photon echo intensity as a function of the temporal distance between both excitation pulses exhibits a nonexponential decay; (b) data analysis on the basis of a superposition of several dephasing processes leads to three characteristic dephasing time domains (A, B, and C) with markedly different wavelength dependencies of dephasing time and relative amplitude, T//2**A less than approximately equals 1.7 ps from 640 to 675 nm, T//2**B = 4-13 ps over the whole wavelength region of 640 to 690 nm, and T//2**C greater than or equivalent 40 ps from 675 to 68...

  4. Synthesis and spectroscopic studies of biologically active tetraazamacrocyclic complexes of Mn(II, Co(II, Ni(II, Pd(II and Pt(II

    Directory of Open Access Journals (Sweden)

    Monika Tyagi

    2014-01-01

    Full Text Available Complexes of Mn(II, Co(II, Ni(II, Pd(II and Pt(II were synthesized with the macrocyclic ligand, i.e., 2,3,9,10-tetraketo-1,4,8,11-tetraazacycoletradecane. The ligand was prepared by the [2 + 2] condensation of diethyloxalate and 1,3-diamino propane and characterized by elemental analysis, mass, IR and 1H NMR spectral studies. All the complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, IR, electronic and electron paramagnetic resonance spectral studies. The molar conductance measurements of Mn(II, Co(II and Ni(II complexes in DMF correspond to non electrolyte nature, whereas Pd(II and Pt(II complexes are 1:2 electrolyte. On the basis of spectral studies an octahedral geometry has been assigned for Mn(II, Co(II and Ni(II complexes, whereas square planar geometry assigned for Pd(II and Pt(II. In vitro the ligand and its metal complexes were evaluated against plant pathogenic fungi (Fusarium odum, Aspergillus niger and Rhizoctonia bataticola and some compounds found to be more active as commercially available fungicide like Chlorothalonil.

  5. DNA damage by the cobalt (II) and zinc (II) complexes of ...

    African Journals Online (AJOL)

    Using the single cell gel electrophoresis method, the tetraazamacrocycle Zn(II) complex (Zn(II)-L) and the tetraazamacrocycle Co(II) complex (Co(II)-L) were investigated focusing on their DNA damage to Tetrahymena thermophila. When the cells were treated with the 0.05, 0.25 and 0.50 mg/ml Zn(II)-L, the tail length ...

  6. DNA damage by the cobalt (II) and zinc (II) complexes of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... Using the single cell gel electrophoresis method, the tetraazamacrocycle Zn(II) complex (Zn(II)-L) and the tetraazamacrocycle Co(II) complex (Co(II)-L) were investigated focusing on their DNA damage to. Tetrahymena thermophila. When the cells were treated with the 0.05, 0.25 and 0.50 mg/ml Zn(II)-L, the.

  7. Synthesis, optical and thermal behaviour of palladium(II) complexes ...

    Indian Academy of Sciences (India)

    shows that all the ligands and Pd(II) complexes exhibit enantiotropic mesophases. The ligands with n-octyloxy and n-decyloxy flexible chains exhibit the nematic (N) and smectic A (SmA) phases whilst the Pd(II) complexes show exclusive SmA phase. The SmA phase observed in Pd(II) complexes can be supported by the ...

  8. A complex molecular interplay of auxin and ethylene signaling pathways is involved in Arabidopsis growth promotion by Burkholderia phytofirmans PsJN

    Directory of Open Access Journals (Sweden)

    María Josefina Poupin

    2016-04-01

    Full Text Available Modulation of phytohormones homeostasis is one of the proposed mechanisms to explain plant growth promotion induced by beneficial rhizobacteria (PGPR. However, there is still limited knowledge about the molecular signals and pathways underlying these beneficial interactions. Even less is known concerning the interplay between phytohormones in plants inoculated with PGPR. Auxin and ethylene are crucial hormones in the control of plant growth and development, and recent studies report an important and complex crosstalk between them in the regulation of different plant developmental processes. The objective of this work was to study the role of both hormones in the growth promotion of Arabidopsis thaliana plants induced by the well-known PGPR Burkholderia phytofirmans PsJN. For this, the spatiotemporal expression patterns of several genes related to auxin biosynthesis, perception and response and ethylene biosynthesis were studied, finding that most of these genes showed specific transcriptional regulations after inoculation in roots and shoots. PsJN-growth promotion was not observed in Arabidopsis mutants with an impaired ethylene (ein2-1 or auxin (axr1-5 signaling. Even, PsJN did not promote growth in an ethylene overproducer (eto2, indicating that a fine regulation of both hormones signaling and homeostasis is necessary to induce growth of the aerial and root tissues. Auxin polar transport is also involved in growth promotion, since PsJN did not promote primary root growth in the pin2 mutant or under chemical inhibition of transport in wild type plants. Finally, a key role for ethylene biosynthesis was found in the PsJN-mediated increase in root hair number. These results not only give new insights of PGPR regulation of plant growth but also are also useful to understand key aspects of Arabidopsis growth control.

  9. SPECIATION OF L-ASPARTIC ACID COMPLEXES OF Co(II), Ni(II ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Chemical speciation of binary complexes of Co(II), Ni(II), Cu(II) and Zn(II) with L-aspartic acid was investigated pH-metrically in acetonitrile- and ethylene glycol-water mixtures. The stability constants were calculated using the computer program MINIQUAD75. The best-fit chemical models were selected based ...

  10. Studies on transition metal complexes of herbicidal compounds. II ...

    African Journals Online (AJOL)

    2(2-Hydroxyethyl)hydrazino-4-ethylamino-6-isopropylamino-s-triazine (HEATZ), a derivative of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine, atrazine (ATZ) – a well known herbicide has been studied for complex formation with cobalt(II), nickel(II), and copper(II). Analytical, conductance, thermal, and spectral studies ...

  11. Zinc (II) metal ion complexes of Chitosan: Toward heterogeneous ...

    African Journals Online (AJOL)

    The Application of Zn(II)-Chit for the polymerization of VAc yielded PVAc in good yield. The catalyst efficiency of Zn(II)-Chit for the polymerization of VAc was considerably high in terms of induction period and percentage yield of PVAc. Keywords: Chitosan, Zn(II)-Chitosan Complex, Catalyst, Polymerization, Polyvinyl Acetate ...

  12. Topoisomerase II poisoning by indazole and imidazole complexes ...

    Indian Academy of Sciences (India)

    The clinical use of these compounds however was hindered due to toxic side effects on the human body. Our present study on topoisomerase II poisoning by these compounds shows that they effectively poison the activity of topoisomerase II by forming a ternary cleavage complex of DNA, drug and topoisomerase II.

  13. Copper(II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

    Unknown

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

  14. Zinc (II) complexes of carboxamide derivatives: Crystal structures ...

    Indian Academy of Sciences (India)

    The two complexes were characterized by physicochemical and spectroscopic tools, and by X-ray crystal structures of both ligands and the complex 1. In complex 1, zinc(II) is chelated by three ligands with a distorted octahedral geometry. The DNA-binding properties of zinc complexes 1 and 2 have been investigated by ...

  15. studies on transition metal complexes of herbicidal compounds. ii

    African Journals Online (AJOL)

    a

    Cobalt(II) complex exhibits thermochromism. Antimicrobial studies on E. coli and S. aureus show the absence of growth inhibitory activities for HEATZ and its metal complexes which is attributed to the combined effect of derivatization of ATZ and metal complexation. KEY WORDS: Metal complexes, Atrazine derivatives, ...

  16. Studies on Bis(Para Anisidine Acetylacetonato) Nickel (II) Complex ...

    African Journals Online (AJOL)

    Studies on Bis(Para Anisidine Acetylacetonato) Nickel (II) Complex. HN Aliyu, UL Bilyamin. Abstract. Schiff base was prepared from the reaction of para anisidine and acetylacetone. Bis(para anisidineacetylacetonato)nickel(II) complex was synthesized by the reaction of the prepared para anisidineacetylacetone ligand and ...

  17. Carboxylate-bridged Cu(II) coordination polymeric complex ...

    Indian Academy of Sciences (India)

    SABITHAKALA THATITURI

    Keywords. Copper(II)polymeric complex; ferromagnetism; electrochemical studies; crystal structure. ... The electron transfer mechanism of copper(II) complex ... EPR spec- trum was obtained using BRUKER Xenon EMX-ER073 spectrometer. X-ray powder diffractograms were recorded on a SMART Bruker D8 advance X-ray ...

  18. New mixed ligand complexes of ruthenium (II) that incorporate a ...

    Indian Academy of Sciences (India)

    New mixed ligand complexes of ruthenium(II) that incorporate a modified phenanthroline ligand: Synthesis, spectral characterization and DNA binding. S Murali C V ... Fulltext. Click here to view fulltext PDF ... Ruthenium(II) complexes; modified phenanthroline ligand; spectroscopy; DNA binding; fluorescence enhancement.

  19. URANYL(II)- NTA-CYSTEINE COMPLEXES BY PAPER ...

    African Journals Online (AJOL)

    a

    of a spot of metal ion under an electric field with the complexants added to the background electrolyte at pH 8.5. ... Lead(II) and uranyl(II) are toxic metal ions because they are harmful even at very low concentration. Therefore ... studies on complexation reactions of divalent lead and uranyl is also of interest because of their.

  20. Nickel(II) and copper(II) complexes with humic acid anions and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Ryabova, I.N. [Kazakh Academy of Science, Karaganda (Kazakhstan)

    2008-01-15

    Complexation of Ni(II) and Cu(II) in aqueous solutions with anions of humic acids, extracted from naturally oxidized coal, and with their hydroxymethyl derivatives is studied spectrophotometrically and potentiometrically. The complexation stoichiometry and the stability constants of the complexes are determined.

  1. Transition metal M(II complexes with isonicotinoylhydrazone-9-anthraldehyde

    Directory of Open Access Journals (Sweden)

    Dianu M.L.

    2010-01-01

    Full Text Available New complexes of isonicotinoylhydrazone-9-anthraldehyde with Cu(II, Co(II and Ni(II have been prepared and characterized by analytical and physico-chemical techniques, such as elemental and thermal analyses, magnetic susceptibility and conductivity measurements, and electronic, EPR and IR spectral studies. The infrared spectral studies revealed the bidentate or monodentate nature of the Schiff base in the complexes; the pyridine nitrogen does not participate in the coordination. A tetrahedral geometry is suggested for the nitrate-complexes and an octahedral geometry for the others. Thermal studies support the chemical formulation of these complexes.

  2. Mass spectrometry and potentiometry studies of Pb(II)-, Cd(II)- and Zn(II)-cystine complexes.

    Science.gov (United States)

    Furia, Emilia; Aiello, Donatella; Di Donna, Leonardo; Mazzotti, Fabio; Tagarelli, Antonio; Thangavel, Hariprasad; Napoli, Anna; Sindona, Giovanni

    2014-01-21

    Cd(II)-, Pb(II)- and Zn(II)-cystine complexes were investigated by potentiometric and different mass spectrometric (MS) methodologies. Laser desorption mass spectrometry has provided both the composition and structure of metal-cystine complexes according to the speciation models proposed on the basis of the potentiometric data. Detection of neutral complexes was achieved by protonation or electrochemical reduction during mass spectrometric experiments. The redox activity of metal-cystine complexes was confirmed by laser desorption and charge transfer matrix assisted laser assisted MS experiments, which allowed us to observe the formation of complexes with a reduction of cystine. The stoichiometry of Cd(II)-, Pb(II)- and Zn(II)-cystine complexes was defined by observing the isotopic pattern of the investigated compound. The results suggest that interaction occurs through the carboxylate group of the ligand.

  3. Cross-reconstitution of the extrinsic proteins and photosystem II complexes from Chlamydomonas reinhardtii and Spinacia oleracea.

    Science.gov (United States)

    Suzuki, T; Ohta, H; Enami, I

    2005-06-01

    Cross-reconstitution of the extrinsic proteins and Photosystem II (PS II) from a green alga, Chlamydomonas reinhardtii, and a higher plant,Spinacia oleracea, was performed to clarify the differences of binding properties of the extrinsic proteins between these two species of organisms. (1) Chlamydomonas PsbP and PsbQ directly bound to Chlamydomonas PS II independent of the other extrinsic proteins but not to spinach PS II. (2) Chlamydomonas PsbP and PsbQ directly bound to the functional sites of Chlamydomonas PS II independent of the origins of PsbO, while spinach PsbP and PsbQ only bound to non-functional sites on Chlamydomonas PS II. (3) Both Chlamydomonas PsbP and spinach PsbP functionally bound to spinach PS II in the presence of spinach PsbO. (4) While Chlamydomonas PsbP functionally bound to spinach PS II in the presence of Chlamydomonas PsbO, spinach PsbP bound loosely to spinach PS II in the presence of Chlamydomonas PsbO with no concomitant restoration of oxygen evolution. (5) Chlamydomonas PsbQ bound to spinach PS II in the presence of Chlamydomonas PsbP and PsbO or spinach PsbO but not to spinach PS II in the presence of spinach PsbP and Chlamydomonas PsbO or spinach PsbO. (6) Spinach PsbQ did not bind to spinach PS II in the presence of Chlamydomonas PsbO and PsbP. On the basis of these results, we showed a simplified scheme for binding patterns of the green algal and higher plant extrinsic proteins with respective PS II.

  4. Copper(II and lead(II complexation by humic acid and humic-like ligands

    Directory of Open Access Journals (Sweden)

    IVANA KOSTIĆ

    2011-09-01

    Full Text Available The stability of metal–humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II and Pb(II with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25 °C and at an ionic strength of 0.01 mol dm-3 (NaCl using the Schubert ion-exchange method and its modified form. The stability constants were calculated from the experimental data by the Schubert method for complexes with benzoic and humic acid. A modified Schubert method was used for the determination of the stability constants of the complexes with salicylic acid. It was found that Cu(II and Pb(II form mononuclear complexes with benzoic and humic acid while with salicylic acid both metals form polynuclear complexes. The results indicate that Pb(II has a higher binding ability than Cu(II to all the investigated ligands. The Cu(II–salicylate and Pb(II–salicylate complexes showed noticeable higher stability constants compared with their complexes with humic acid, while the stabilities of the complexes with benzoic acid differed less. Salicylic and benzoic acids as humic-like ligands can be used for setting the range of stability constants of humic complexes with Cu(II and Pb(II.

  5. Electrochemical, Antifungal, Antibacterial and DNA Cleavage Studies of Some Co(II), Ni(II), Cu(II) and Zn(II)-Copolymer Complexes

    OpenAIRE

    Dhanaraj, C. Justin; Nair, M. Sivasankaran

    2008-01-01

    Cyclic voltammetric measurements were performed for Co(II), Ni(II), Cu(II) and Zn(II) complexes of 1 : 1 alternating copolymer, poly(3-nitrobenzylidene-1-naphthylamine-co-succinic anhydride) (L) and Ni(II) and Cu(II) complexes of 1 : 1 alternating copolymer, poly(3-nitrobenzylidene-1-naphthylamine-co-methacrylic acid) (L1). The in vitro biological screening effects of the investigated compounds were tested against the fungal species including Aspergillus niger, Rhizopus stolonifer, Aspergillu...

  6. Structural and optical properties of tin (II) sulfide thin films deposited using organophosphorus precursor (Ph3PS)

    Science.gov (United States)

    Assili, Kawther; Alouani, Khaled; Vilanova, Xavier

    2017-02-01

    Tin sulfide (SnS) thin films have been deposited onto glass substrates using triphenylphosphine sulfide (Ph3PS) as a sulfur precursor in a chemical vapor deposition reactor in a temperature range of 250 °C-400 °C. The influence of the sulphidisation temperature in the crystal structure, surface morphology, chemical composition and optical properties has been investigated. X-ray diffraction, energy dispersive analysis of x-rays, and Raman spectroscopy showed that pure SnS thin films have been successfully obtained at 250 °C. All the deposited films were polycrystalline and showed orthorhombic structure, with a preferential orientation according to the direction . The optical measurements showed that the films deposited exhibited a direct allowed transition and have a relatively high absorption coefficient. The presence of mixed tin sulfide phases granted by the variation of the sulphidisation temperature has affected the optical properties of the deposited films. The refractive index (n) and extinction coefficient (k), has low values compared to conventional semiconductor materials. The grown films can be considered as a good light absorbing material and a promising candidate for application in optoelectronic devices.

  7. A new Mannich base and its transition metal (II) complexes ...

    Indian Academy of Sciences (India)

    The monomeric and non-electrolytic nature of the complexes is evidenced by their magnetic susceptibility and low conductance data. The electrochemical property of the ligand and its complexes in acetonitrile solution was studied by cyclic voltammetry. The X-band ESR spectra of the Cu(II) complex in DMSO at 300 and 77 ...

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

    Indian Academy of Sciences (India)

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

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

    Science.gov (United States)

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

    1998-01-01

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

  10. Chemical speciation of L-glutamine complexes with Co(II), Ni(II) and ...

    African Journals Online (AJOL)

    The impact of cationic micelles on the protonation equilibria of L-glutamine and chemical speciation of its complexes with Co(II), Ni(II) and Cu(II) have been studied by monitoring hydrogen ion concentration pH metrically at 303 K and at an ionic strength of 0.16 M. The protonation constants and binary stability constants ...

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

    Science.gov (United States)

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

    1999-04-01

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

  12. STUDIES ON SOME VO(IV), Ni(II) AND Cu(II) COMPLEXES OF NON ...

    African Journals Online (AJOL)

    a

    planar complexes are diamagnetic [23]. The Ni(II) complexes reported in this work, are diamagnetic and consequently, four coordinate, square planar in geometry [19-20, 23], ruling out the presence of paramagnetic, tetrahedral forms. The room temperature magnetic moments of the copper(II) compounds are expected to be.

  13. Studies on some VO(IV), Ni(II) and Cu(II) complexes of non ...

    African Journals Online (AJOL)

    The ligands are tetradentately coordinating via the imine N and enolic O atoms, resulting in 5-coordinate square-pyramidal geometry for the VO(IV) complexes and 4-coordinate square-planar geometry for the Ni(II) and Cu(II) complexes. The assignment of geometry is supported by magnetic and spectral measurements.

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

    African Journals Online (AJOL)

    B. S. Chandravanshi

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

  15. Complex with fullerenol and copper (II

    Directory of Open Access Journals (Sweden)

    Đorđević Aleksandar N.

    2009-01-01

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

  16. Synthesis and luminescence properties of polymeric complexes of Cu(II), Zn(II) and Al(III) with 8-hydroxyquinoline side group-containing polystyrene

    Science.gov (United States)

    Gao, Baojiao; Wei, Xiaopeng; Zhang, Yanyan

    2013-01-01

    Three kinds of metalloquinolate-containing polystyrene were prepared via a polymer reaction and a coordination reaction. 5-Chloromethyl-8-hydroxyquinoline (CHQ) was first prepared through the chloromethylation reaction of 8-hydroxyquinoline (HQ) with 1,4-bichloromethoxy-butane as chloromethylation reagent. A polymer reaction, Friedel-Crafts alkylation reaction, was carried out between polystyrene (PS) and CHQ in the presence of Lewis catalyst, and HQ was bonded onto the side chains of PS, obtaining 8-hydroxyquinoline-functionalized Polystyrene, HQ-PS. And then, by using one-pot method with two-stage procedures, the coordination reaction of HQ-PS and small molecule HQ with metal ions including Al(III), Zn(II) and Cu(II) ions, was allowed to be carried out, and three polymeric metalloquinolates, AlQ3-PS, ZnQ2-PS and CuQ2-PS, were successfully prepared, respectively. In the chemical structures of these polymeric metalloquinolates, metalloquinolates were chemically attached onto the side chains of PS. HQ-PS and three polymeric metalloquinolates were fully characterized by FTIR, 1H NMR and TGA. The luminescence properties of the three polymeric metalloquinolates were mainly investigated by UV/Vis absorption spectra and fluorescence emission spectra in solutions and in solid film states. When excited by the ray at about 365 nm, the three polymeric metalloquinolates have blue-green luminescence, and the main emission peaks in the DMF solutions are located at 490, 482 and 502 nm for AlQ3-PS, ZnQ2-PS and CuQ2-PS, respectively. As compared with their emissions in solutions, the emissions in solid film states are red-shifted to some extent, and the main emission peaks are located at 500, 488 and 510 nm for AlQ3-PS, ZnQ2-PS and CuQ2-PS, respectively. Besides, these polymeric metalloquinolates have higher thermal stability than PS as polymeric skeleton.

  17. Photocleavage of DNA by copper(II) complexes

    OpenAIRE

    Chakravarty, Akhil R

    2006-01-01

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

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

    Indian Academy of Sciences (India)

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

  19. Synthesis and characterization of mixed ligand complexes of Zn (II ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 117; Issue 3. Synthesis and characterization of mixed ligand complexes of Zn(II) and Co(II) with amino acids: Relevance to zinc binding sites in zinc fingers. P Rabindra Reddy M Radhika P Manjula. Volume 117 Issue 3 May 2005 pp 239-246 ...

  20. Carboxylate-bridged Cu (II) coordination polymeric complex ...

    Indian Academy of Sciences (India)

    Carboxylate-bridged Cu(II) coordination polymeric complex: synthesis, crystal structure, magnetic properties, DNA binding and electrochemical studies ... Abstract. A novel water-soluble carboxylate-bridged copper(II) coordination polymer,Cu-BIG was formed by the reaction of Cu(ClO₄)₂ ·6H₂O and tridentate ...

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

    African Journals Online (AJOL)

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

  2. Complexation of the fungal metabolite tenuazonic acid with copper (II), iron (III), nickel (II), and magnesium (II) ions.

    Science.gov (United States)

    Lebrun, M H; Duvert, P; Gaudemer, F; Gaudemer, A; Deballon, C; Boucly, P

    1985-07-01

    Tenuazonic acid (TA) is a phytotoxin produced by a fungal pathogen of rice, Pyricularia oryzae. We have synthesized and characterized the metal complexes of TA with copper (II), iron (III), nickel (II), and magnesium (II). The stoichiometry of the complexes determined by microanalysis and mass spectroscopy (D/CI) are Cu(II)TA2, Fe(III)TA3, Ni(II)TA2, and Mg(TA)2. Voltammograms of Fe(III)TA3, and Cu(II)TA2 in methanolic solutions confirmed this stoichiometry. Ni(II)TA2 paramagnetism and visible absorption data suggest an octahedral geometry. Fe(III)TA3 showed a characteristic visible absorption at 450 nm. Addition of Fe(III)Cl3 and Mg(II)Cl2 did not reverse the toxicity of NaTA to rice and bacterial cells, showing that this toxicity is not due to the privation of the cells of these metals essential for cell growth.

  3. L-α-Valine Cobalt (II) Complex

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    base is crystalline white and has a yield of 66%. The prepared complex is pale ... Weightings were carried out on digital balance model, AB 54 to four decimal places. Infrared spectral analyses were ... The interaction of L-valine and salicyladehyde gave a white crystalline N–(2 – hydroxybenzyl) - L - α - valine Schiff base.

  4. Synthesis, Characterization, and Biological Activity of Nickel (II) and Palladium (II) Complex with Pyrrolidine Dithiocarbamate (PDTC)

    OpenAIRE

    Sk Imadul Islam; Suvendu Bikash Das; Sutapa Chakrabarty; Sudeshna Hazra; Akhil Pandey; Animesh Patra

    2016-01-01

    The synthesis of square planar Ni(II) and Pd(II) complexes with pyrrolidine dithiocarbamate (PDTC) was characterized by elemental, physiochemical, and spectroscopic methods. Two complexes were prepared by the reaction of nickel acetate and palladium acetate with pyrrolidine dithiocarbamate (PDTC) in 1 : 2 molar ratio. The bovine serum albumin (BSA) interaction with complexes was examined by absorption and fluorescence spectroscopic techniques at pH 7.4. All the spectral data suggest that coor...

  5. Differentials on graph complexes II: hairy graphs

    Science.gov (United States)

    Khoroshkin, Anton; Willwacher, Thomas; Živković, Marko

    2017-10-01

    We study the cohomology of the hairy graph complexes which compute the rational homotopy of embedding spaces, generalizing the Vassiliev invariants of knot theory. We provide spectral sequences converging to zero whose first pages contain the hairy graph cohomology. Our results yield a way to construct many nonzero hairy graph cohomology classes out of (known) non-hairy classes by studying the cancellations in those sequences. This provide a first glimpse at the tentative global structure of the hairy graph cohomology.

  6. I. Redox chemistry of bimetallic fulvalene complexes II. Oligocyclopentadienyl complexes

    Energy Technology Data Exchange (ETDEWEB)

    Brown, David Stephen [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley Lab., CA (United States). Chemical Sciences Div.

    1993-11-01

    The electrochemistry of the heterobimetallic complexes (fulvalene)WFe(CO)5 (30) and (fulvalene)WRu(CO)5 (31) has been investigated. Compound 30 is reduced in two one-electron processes, and this behavior was exploited synthetically to prepare a tetranuclear dimer by selective metal reduction. Complex 31 displayed a distinction between the metals upon reoxidation of the dianion, allowing the formation of a dimer by selective metal anion oxidation. The redox behavior of 30 led to an investigation of the use of electrocatalysis to effect metal-specific ligand substitution. It was found that reduction of 30 with a catalytic amount of CpFe(C6Me6) (97) in the presence of excess P(OMe)3 or PMe5 led to the formation of the zwitterions (fulvalene)[W(CO)3-][Fe(CO)PR3+] (107, R = P(OMe)3; 108, R = PMe3). Compound 31 also displayed unique behavior with different reducing agents, as the monosubstituted zwitterion (fulvalene)[W(CO)3-][Ru(CO)2(PMe3+] was obtained when 97 was used while the disubstituted complex (fulvalene) [W(CO)3-] [Ru(CO)(PMe3)2+] was produced when Cp*Fe(C6Me6) was the catalyst. Potential synthetic routes to quatercyclopentadienyl complexes were also explored. Various attempts to couple heterobimetallic fulvalene compounds proved to be unsuccessful. 138 refs.

  7. Heteroleptic neutral Ru(II) complexes based photodiodes

    Science.gov (United States)

    Elgazzar, Elsayed; Dayan, O.; Serbetci, Z.; Dere, A.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; El-Tantawy, Farid; Farooq, W. A.; Yakuphanoglu, F.

    2017-07-01

    The two complexes Ru (II) containing 2,6-bis(benzimidazol-2-yl)pyridine and 2-pyridine and 2-quinoline carboxylates were synthesized to fabricate organic photodiodes. The electrical properties of Au / Ru (II) complex (I) / n - Si / Al and Au / Ru (II) complex (II) / n - Si / Al diodes were investigated by current-voltage and capacitance-voltage measurements. The fabricated devices give a high rectification behavior with rectification ratio of 2.4 × 104 -2.1 × 103 at ± 4 V. The diodes exhibited a high photoconductivity based on trap levels within band gap. The series resistance and barrier height were calculated from (C - V) measurements and compared to other of (I - V) . The obtained results indicate that the prepared photodiodes can be used as photosensor for optoelectronic applications.

  8. Structural determination of the photosystem II core complex from spinach

    NARCIS (Netherlands)

    Irrgang, Klaus-D.; Boekema, Egbert J.; Vater, Joachim; Renger, Gernot

    1988-01-01

    A photosystem II core complex was purified with high yield from spinach by solubilization with β-dodecylmaltoside. The complex consisted of polypeptides with molecular mass 47, 43, 34, 31, 9 and 4 kDa and some minor components, as detected by silver-staining of polyacrylamide gels. There was no

  9. Photocleavage of DNA by copper(II) complexes

    Indian Academy of Sciences (India)

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

  10. Synthesis and structure of ruthenium(II) ternary complexes involving ...

    Indian Academy of Sciences (India)

    Administrator

    All the complexes are diamagnetic (low spin d6,. S = 0) and show intense bands corresponding to metal to ligand charge-transfer transitions and inter-ligand transitions in the UV-Vis spectra. All the complexes show one reversible oxidation due to ruthenium(II)–ruthenium(III) in the anodic region of the cyclic voltammogram.

  11. 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 ...

  12. (Ii) Complexes with Schiff Bases Derived From 2 – Hydroxy

    African Journals Online (AJOL)

    Schiff base ligands derived from 2-hydroxy-1-naphthaldehyde and some aliphatic diamines were synthesized and characterized. Each of the ligands was used to form complex with Mn (II). Solubility, elemental analyses and IR spectra were carried evaluated. Elemental analyses of the complexes for C, N and H revealed 1:1 ...

  13. Model of the extradiol-cleaving manganese(II) dioxygenase penicillamine-manganese(II) complex.

    Science.gov (United States)

    Sakurai, H; Shimomura, S; Yoshimura, T

    1983-09-15

    The structure of the green penicillamine(Pen)-Mn(II) complex prepared under air was determined from its electronic spectra, molar ratio, ESR spectra and oxygen consumptions at various pH values and by potentiometric titration. Pen bound with Mn(II) in a molar ratio of approximately 1:1 forming coordination bonds with a thiolate and an amino group, and the complex consumed about 1 mol of oxygen at pH 9-10. Oxygen binding to this complex was found to be reversible at room temperature. The oxygen adduct complex catalysed oxidative extradiol-cleavage of catechol at pH 7.0-7.5. The Pen-Mn(II)-02 complex seems to be a simple model of extradiol-cleaving manganese(II) dioxygenase, which was recently found in Bacillus brevis.

  14. Studies of Mn (II) and Ni (II) complexes with Schiff base derived from ...

    African Journals Online (AJOL)

    However, manganese(II) complex is insoluble in most organic solvents but soluble in dimethylsulphoxide (DMSO). The molar conductance of the complexes measured are low, indicating their non-electrolytic nature. The potentiometric and spectrophotometric studies of the complex compounds revealed 1:1 metal to ligand ...

  15. Studies of mn (ii) and ni (ii) complexes with schiff base derived from ...

    African Journals Online (AJOL)

    However, manganese(II) complex is insoluble in most organic solvents but soluble in dimethylsulphoxide (DMSO). The molar conductance of the complexes measured are, indicating their non-electrolytic nature. The potentiometric and spectrophotometric studies of the complex compounds revealed 1:1 metal to ligand ratio.

  16. Vibrational spectra of Cu(II), Cu(I), Ni(II), Pd(II), Pt(II) and Hg(II) complexes with dithizone

    Science.gov (United States)

    Michalska, Danuta; Kowal, Andrzei T.

    1985-01-01

    The far i.r. spectra of Cu(II), Cu(I) and Ni(II) complexes with dithizone are presented. The assignment of the metal—ligand vibrations was carried out by 63Cu/ 65Cu and 58Ni/ 62Ni isotopic substitution. Resonance Raman spectra of Hg(II), Pd(II), Pt(II), Cu(II) and Cu(I) complexes were measured. Excitation profiles of the enhanced Raman modes of Hg(II) dithizonate allowed us to identify vibrations associated with the chromophoric azo group. It is concluded that Pd(II) dithizonate and Pt(II) dithizonate are N, S coordinated and form a trans square-planar structure, whereas in Cu(I) dithizonate the Cu(I) ion forms a strong bond with the sulfur atom and a weak secondary bond with the azo nitrogen as well as with sulfur atoms from the neighboring molecules conferring a tetrahedral configuration on the coordination sphere and polymeric structure of the complex.

  17. A low-spin Fe(III) complex with 100-ps ligand-to-metal charge transfer photoluminescence

    DEFF Research Database (Denmark)

    Chabera, Pavel; Liu, Yizhu; Prakash, Om

    2017-01-01

    Transition-metal complexes are used as photosensitizers(1), in light-emitting diodes, for biosensing and in photocatalysis(2). A key feature in these applications is excitation from the ground state to a charge-transfer state(3,4); the long charge-transfer-state lifetimes typical for complexes...

  18. Cu(II) chloride complexes in frozen ethanol solution

    Energy Technology Data Exchange (ETDEWEB)

    Plyusnin, V.F.; Usov, O.M.

    1985-12-01

    This paper examines the photochemical properties of Cu(II) chloride complexes in frozen organic matrices. It was necessary to determine the spectroscopic parameters and conditions of the existence of individual complexes at 77 K. Ethanol was saturated with gaseous HC1, the solubility of which is appreciably greater than that of such salts as LiC1, NaC1, or KC1. The spectroscopic parameters of the complexes are determined and discussed.

  19. Cohesin regulates major histocompatibility complex class II genes through interactions with MHC-II insulators1

    Science.gov (United States)

    Majumder, Parimal; Boss, Jeremy M.

    2011-01-01

    Cohesin is a multiprotein ringed complex that is most well known for its role in stabilizing the association of sister chromatids between S phase and M. More recently cohesin was found to be associated with transcriptional insulators, elements that are associated with the organization of chromatin into regulatory domains. The human major histocompatibility complex class II (MHC-II) locuscontains ten intergenic elements, termed MHC-II insulators, which bind the transcriptional insulator protein CCCTC transcription factor (CTCF). MHC-II insulators interact with each other forming a base architecture of discrete loops and potential regulatory domains. When MHC-II genes are expressed, their proximal promoter regulatory regions reorganize to the foci established by the interacting MHC-II insulators. MHC-II insulators also bind cohesin, but the functional role of cohesin in regulating this system is not known. Here we show that the binding of cohesin to MHC-II insulators occurred irrespective of MHC-II expression but was required for optimal expression of the HLA-DR and HLA-DQ genes. In a DNA dependent manner, cohesin subunits interacted with CTCF and the MHC-II specific transcription factors RFX and CIITA. Intriguingly, cohesin subunits were important for DNA looping interactions between the HLA-DRA promoter region and a 5’ MHC-II insulator but were not required for interactions between the MHC-II insulators themselves. This latter observation introduces cohesin as a regulator of MHC-II expression by initiating or stabilizing MHC-II promoter regulatory element interactions with the MHC-II insulator elements; events which are required for maximal MHC-II transcription. PMID:21911605

  20. A multicenter, phase II study of bortezomib (PS-341) in patients with unresectable or metastatic gastric and gastroesophageal junction adenocarcinoma.

    Science.gov (United States)

    Shah, Manish A; Power, Derek G; Kindler, Hedy L; Holen, Kyle D; Kemeny, Margaret M; Ilson, David H; Tang, Laura; Capanu, Marinela; Wright, John J; Kelsen, David P

    2011-12-01

    The transcription factor nuclear factor-kB (NFkB) is implicated in gastric cancer carcinogenesis and survival, and its inhibition by proteosome inhibition is associated with preclinical gastric cancer anti-tumor activity. We examined the single agent efficacy of bortezomib, a selective proteasome inhibitor, in gastric adenocarcinoma. We performed a phase II trial of bortezomib in patients with advanced gastric adenocarcinoma. Bortezomib 1.3 mg/m(2) was administered on days 1, 4, 8, and 11 every 21 days. The primary endpoint was objective response rate(RR); the null hypothesis was RR <1% versus the alternative ≥15%. One response in the first stage(15 patients) was required before proceeding with an additional 18 patients. If at least 2 or more responses out of 33 were observed, further study with bortezomib was warranted. Correlative studies evaluated pre-treatment tumor expression of NFkB, IkB, p53, p21, and cyclin D1. We enrolled 16 patients (15 evaluable for response) from four institutions. No patients demonstrated an objective response(95% CI, 0-22%); one patient achieved stable disease. Fourteen out of 16 patients experienced ≥ grade 2 toxicity. The most common toxicity was fatigue in six patients (n = 4 grade 2, n = 2 grade 3). Seven patients experienced neuropathy (n = 5 grade 1, and 1 each grade 2 and 3). Seven (60%) had high cytoplasmic staining for NFkB. Single agent bortezomib is inactive in metastatic gastric adenocarcinoma and should not be pursued. Future study of proteasome inhibition in gastric adenocarcinoma should be considered in combination with targeted inhibition of other non-overlapping oncogenic pathways as a potential rational approach.

  1. STUDIES OF MN (II) AND NI (II) COMPLEXES WITH SCHIFF BASE ...

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... Department of Chemistry Bayero University, P. M. B. 3011, Kano, Nigeria. Correspondence author: hnuhu2000@yahoo.com. ABSTRACT. The complexes of Mn (II) and Ni (II) with Schiff base derived from salicylaldehyde and 2- aminobenzoic acid have been prepared and characterized by gravimetry, ...

  2. Cobalt (III), nickel (II) and ruthenium (II) complexes of 1, 10 ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 112; Issue 1. Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10-phenanthroline family of ligands: DNA binding and photocleavage studies. S Arounaguiri D Easwaramoorthy A Ashokkumar Aparna Dattagupta Bhaskar G Maiya. Inorganic and Analytical Volume ...

  3. Potentiometric and spectrophotometric studies of Mn{sup II} and Ni{sup II} cimetidine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kanumfre, Francieli; Lima, Eliane M. de; Scheidt, Gabriele; Carneiro, Paulo I.B.; Rosso, Neiva D., E-mail: ndrosso@uepg.b [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Quimica

    2010-07-01

    Cimetidine is an important hydrogen histamine receptor which has the ability to chelate metal ions in blood plasma and in different tissues. This study aimed to determine the stability constants for the cimetidine ligand with Mn{sup II} and Ni{sup II} metallic ions, synthesizing complexes and characterizing them by infrared spectroscopy, IR, and hydrogen nuclear magnetic resonance, {sup 1}H NMR. Cimetidine protonation constant regarding to the imidazole group was log K 7.05 and the stability constants for Mn{sup II} and Ni{sup II} complexes, ML{sub 2} species were log K 3.75 and 2.97, respectively, in 0.100 mol L{sup -1} KCl. The interpretation of IR and {sup H}1 NMR spectra for complexes Mn{sup II}-cim{sub 2} and Ni{sup II}-cim{sub 2} indicated that their formation occurs through the sulfur atoms in the thiol group, nitrogen atoms of imidazole ring, and nitrogen atoms of secondary amine. The nitrile group seems to be involved in the complexation of the Ni{sup II}-cim{sub 2} complex. (author)

  4. Synthesis, characterization and cytotoxicity of mixed ligand Mn(II, Co(II and Ni(II complexes

    Directory of Open Access Journals (Sweden)

    Osman Souad A.

    2014-01-01

    Full Text Available Complexes of the type [ML'L(OH(H2O] {where M= Ni(II, Co(II or Mn(II, L'= isatin and HL= 3-(2-phenylhydrazonoacetylacetone, 3-(2-(4-chlorophenylhydrazonoacetylacetone or 3-(2-(4-bromophenylhydrazono-acetylacetone} have been synthesized by equimolar reaction of a metal(II chloride with isatin and 3-(2-(arylhydrazonoacetylacetone. The resulting complexes have been characterized by elemental analyses, molar conductivity, spectral data (IR, 1H NMR, mass and magnetic moments. Furthermore, the ligands and their metal complexes have been screened for their cytotoxicity against different human cancer cell lines by using SRB assay. The results showed that most of the mixed ligand metal complexes have high cytotoxicity in comparison with the reference drugs used.

  5. Speciation of Co(II), Ni(II) and Cu(II) Complexes with L-Glutamic ...

    African Journals Online (AJOL)

    NICO

    2011-08-10

    Aug 10, 2011 ... Chemical speciation of Co(II), Ni(II) and Cu(II) complexes of L-glutamic acid in the presence of Dioxan-Water mixtures at an ionic strength of 0.16 mol L–1 at 303 K was studied pH– metrically. Glu is taken as a model compound for amino acid residues and dioxan is used to mimic the low dielectric constant ...

  6. Formation of binary complexes of Co(II), Ni(II) and Cu(II) with L ...

    African Journals Online (AJOL)

    ... on statistical parameters like crystallographic R factor and sum of the squares of residuals in mass-balance equations. The models for binary complex systems contain the chemical species ML, ML2, MLH, ML2H and ML2H2 for Co(II), Ni(II) and Cu(II) in dioxan-water mixtures. The trend in the variation of stability constants ...

  7. A substituted sulfonamide and its Co (II), Cu (II), and Zn (II) complexes as potential antifungal agents.

    Science.gov (United States)

    Diaz, Jorge R A; Fernández Baldo, Martín; Echeverría, Gustavo; Baldoni, Héctor; Vullo, Daniela; Soria, Delia B; Supuran, Claudiu T; Camí, Gerardo E

    2016-01-01

    A sulfonamide 1-tosyl-1-H-benzo(d)imidazol-2-amine (TBZA) and three new complexes of Co(II), Cu(II), and Zn(II) have been synthesized. The compounds have been characterized by elemental analyses, FTIR, 1 H, and 13 C-NMR spectroscopy. The structure of the TBZA, and its Co(II) and Cu(II) complexes, was determined by X-ray diffraction methods. TBZA and its Co(II) complex crystallize in the triclinic P-1 space group, while the Cu(II) complex crystallizes in the monoclinic P2 1 /c space group. Antifungal activity was screened against eight pathogenic yeasts: Candida albicans (DMic 972576), Candida krusei (DMic 951705), Candida glabrata (DMic 982882), Candida tropicalis (DMic 982884), Candida dubliniensis (DMic 93695), Candida guilliermondii (DMic 021150), Cryptococcus neoformans (ATCC 24067), and Cryptococcus gattii (ATCC MYA-4561). Results on the inhibition of various human (h) CAs, hCA I, II, IV, VII, IX, and XII, and pathogenic beta and gamma CAs are also reported.

  8. Spectroscopic evaluation of Co(II), Ni(II) and Cu(II) complexes derived from thiosemicarbazone and semicarbazone

    Science.gov (United States)

    Chandra, Sulekh; Kumar, Anil

    2007-12-01

    Co(II), Ni(II) and Cu(II) complexes were synthesized with thiosemicarbazone (L 1) and semicarbazone (L 2) derived from 2-acetyl furan. These complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non-electrolytic nature. All the complexes are of high-spin type. On the basis of different spectral studies six coordinated geometry may be assigned for all the complexes except Co(L) 2(SO 4) and Cu(L) 2(SO 4) [where L = L 1 and L 2] which are of five coordinated square pyramidal geometry.

  9. The synthesis and characterization of complexes of zinc(II, cadmium(II, platinum(II and palladium(II with potassium 3-dithiocarboxy-3-aza-5-aminopentanoate

    Directory of Open Access Journals (Sweden)

    SRECKO TRIFUNOVIC

    2004-02-01

    Full Text Available Complexes of zinc(II, cadmium(II, platinum(II and palladium(II with a new polydentate dithiocarbamate ligand, 3-dithiocarboxy-3-aza-5-aminopentanoate (daap-, of the type M(daap2·nH2O (M = Zn(II, Cd(II, n = 2, or M = Pt(II, Pd(II, n = 0, have been prepared and characterized by elemental analysis, IR and UV/VIS spectroscopy, as well as magnetic measurements. The spectra of the complexes suggest a bidentate coordination of the daap- ligand to the metal ions via the sulfur atoms of the deprotonated dithiocarbamato group. The fact that under the same experimental conditions its S-methyl ester does not form complexes could be taken as proof of the suggested coordination mode.

  10. Pseudo-S6 Complex Cations of a Hexakis-N-methylformamide Nickel(II) Complex

    National Research Council Canada - National Science Library

    SAKIYAMA, Hiroshi; MITSUHASHI, Ryoji; MIKURIYA, Masahiro

    2015-01-01

    The nickel(II) complex [Ni(NMF)6](BPh4)2 [NMF = N-methylformamide] [hexakis(N-methylformamide-κO)nickel(II) bis(tetraphenylborate)] was prepared, and characterized by a single-crystal X-ray method...

  11. LOW-TEMPERATURE OZONE DECOMPOSITION BY COMPLEXES OF Cu(II, Co(II AND Mn(II WITH HEXAMETHYLENETETRAMINE

    Directory of Open Access Journals (Sweden)

    A. S. Truba

    2016-04-01

    Full Text Available First, the complexes MCl2*HTMA*xH2O/SiO2 (M = Cu(II, Co(II, Mn(II with hexa-methylenetetramine (HMTA molecule weakly bound with a central M atom (CM ranging from 5.010-7 to 5.010-6 mol/g have been found to catalyse the ozone decomposition. Their activity and turnover number exceeded much those for MCl2*хН2О/ SiO2 acido complexes

  12. A Heteroleptic Ferrous Complex with Mesoionic Bis(1,2,3-triazol-5-ylidene) Ligands: Taming the MLCT Excited State of Iron(II)

    DEFF Research Database (Denmark)

    Liu, Yizhu; Kjær, Kasper Skov; Fredin, Lisa A.

    2015-01-01

    based on sequentially furnishing the Fe-II center with the benchmark 2,2-bipyridine (bpy) ligand and the more strongly sigma-donating mesoionic ligand, 4,4-bis(1,2,3-triazol-5-ylidene) (btz). Complex1 was comprehensively characterized by electrochemistry, static and ultrafast spectroscopy, and quantum...... structure effectively destabilizes the metal-centered (MC) states relative to the triplet metal-to-ligand charge transfer ((MLCT)-M-3) state in 1, rendering it a lifetime of 13ps, the longest to date of a photochemically stable Fe-II complex. Deactivation of the (MLCT)-M-3 state is proposed to proceed via...

  13. Surface complexation of Pb(II) by hexagonal birnessite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, K.; Refson, K.; Sposito, G.

    2010-10-15

    Natural hexagonal birnessite is a poorly-crystalline layer type Mn(IV) oxide precipitated by bacteria and fungi which has a particularly high adsorption affinity for Pb(II). X-ray spectroscopic studies have shown that Pb(II) forms strong inner-sphere surface complexes mainly at two sites on hexagonal birnessite nanoparticles: triple corner-sharing (TCS) complexes on Mn(IV) vacancies in the interlayers and double edge-sharing (DES) complexes on lateral edge surfaces. Although the TCS surface complex has been well characterized by spectroscopy, some important questions remain about the structure and stability of the complexes occurring on the edge surfaces. First-principles simulation techniques such as density functional theory (DFT) offer a useful way to address these questions by providing complementary information that is difficult to obtain by spectroscopy. Following this computational approach, we used spin-polarized DFT to perform total-energy-minimization geometry optimizations of several possible Pb(II) surface complexes on model birnessite nanoparticles similar to those that have been studied experimentally. We first validated our DFT calculations by geometry optimizations of (1) the Pb-Mn oxyhydroxide mineral, quenselite (PbMnO{sub 2}OH), and (2) the TCS surface complex, finding good agreement with experimental structural data while uncovering new information about bonding and stability. Our geometry optimizations of several protonated variants of the DES surface complex led us to conclude that the observed edge-surface species is very likely to be this complex if the singly-coordinated terminal O that binds to Pb(II) is protonated. Our geometry optimizations also revealed that an unhydrated double corner-sharing (DCS) species that has been proposed as an alternative to the DES complex is intrinsically unstable on nanoparticle edge surfaces, but could become stabilized if the local coordination environment is well-hydrated. A significant similarity exists

  14. Network characteristics of individual pigments in cyanobacterial photosystem II core complexes

    Science.gov (United States)

    Lee, Eun; Holme, Petter

    2013-12-01

    Part of the excitation energy transfer (EET) characteristics of the photosystem II (PSII) comes from the interconnection between pigments. To understand the correlation between the EET and the pigments' interaction structure, we construct a network from the EET rates which are related to both the distance between the pigments (chlorophylls and pheophytins) and their spatial orientations. Especially, we investigate how well the PS II core complex's EET functionality can be explained by using only the network topology in Thermosynechococcus vulcanus 1.9 °A. Starting from the Förster theory, we construct a network of EET pathways. For an analysis of the network structure, we calculate common network-structural measures like betweenness centrality, eigenvector centrality and weighted clustering. These measures can reflect the role of individual pigments in the EET network. In our work, we found that some well-known properties were reproduced by the network analysis of the simplified network, which means that the topology of the network encodes functionally relevant information. For example, from the network structural analysis, we can infer that most of the chlorophyll molecules (clorophylls) in the pigment-protein complex CP47 have heightened probability to transfer energy compared with other chlorophylls. We also see that the active branch chlorophylls in the reaction center are characterized by a high eigenvector centrality, a high betweenness centrality and a low weighted clustering coefficient. This is indicative of functionally important vertices.

  15. Copper(II), cobalt(II) and nickel(II) complexes of juglone: synthesis, structure, DNA interaction and enhanced cytotoxicity.

    Science.gov (United States)

    Tabrizi, Leila; Fooladivanda, Mahrokh; Chiniforoshan, Hossein

    2016-12-01

    Three novel copper(II), cobalt(II), and nickel(II) complexes of juglone (Jug) containing 1,10-phenanthroline (phen) ligand, [M(Jug) 2 (phen)] (M = Cu(II), 1, Co(II), 2, and Ni(II), 3), have been synthesized and characterized using, elemental analysis and spectroscopic studies. Their interactions with calf thymus DNA were investigated using viscosity measurements, UV-visible and fluorescence spectrophotometric methods. The catalytic activities on DNA cleavage of the complexes 1-3 were studied, which copper complex 1 showed better catalyst activity in the DNA cleavage process than complexes 2 and 3. The in vitro cytotoxic potential of the complexes 1-3 against human cervical carcinoma (HeLa), human liver hepatocellular carcinoma (HepG-2), and human colorectal adenocarcinoma (HT-29) cells indicated their promising antitumor activity with quite low IC 50 values in the range of 0.09-1.89 μM, which are 75 times lower than those of cisplatin.

  16. Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

    Directory of Open Access Journals (Sweden)

    Tanabe Makoto

    2011-09-01

    Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

  17. Topoisomerase II poisoning by indazole and imidazole complexes ...

    Indian Academy of Sciences (India)

    Unknown

    to even 5-fluorouracil, which is an established cytostatic drug against human gastrointestinal carcinomas. Fruhauf and Zeller (1991) observed that RuInd brings about anti- tumour activity by interacting with DNA and inhibiting. DNA synthesis. The present work analyses the ability of these two complexes to poison topo II. 2.

  18. Ruthenium(II) complexes containing bidentate Schiff bases and ...

    Indian Academy of Sciences (India)

    Unknown

    expensive Schiff base ligands, in this paper, we de- scribe the synthesis, characterisation and catalytic studies of stable ruthenium(II) complexes. The general structure of the Schiff base ligands used in this study is shown in scheme 1. 2. Experimental. RuCl3.3H2O was purchased from Loba-Chemie and used as supplied.

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

    African Journals Online (AJOL)

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

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

    Indian Academy of Sciences (India)

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

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

    Indian Academy of Sciences (India)

    Unknown

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

  2. Nickel (II) complexes containing ONS donor ligands: Synthesis ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 4. Nickel(II) complexes containing ONS donor ligands: Synthesis, characterization, crystal structure and catalytic application towards C-C cross-coupling reactions. Panneerselvam Anitha Rajendran Manikandan Paranthaman Vijayan Govindan Prakash ...

  3. Polypyridyl iron(II) complexes showing remarkable photocytotoxicity ...

    Indian Academy of Sciences (India)

    aditya

    Polypyridyl iron(II) complexes showing remarkable photocytotoxicity in visible light. ADITYA GARAI a. , UTTARA BASU a. , ILA PANT b. , PATURU KONDAIAH*. ,b. AND. AKHIL R. CHAKRAVARTY*. ,a a. Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore. 560012, India. E-mail: ...

  4. Nickel (II) complexes having Imidazol-2-ylidene-N′-phenylurea ...

    Indian Academy of Sciences (India)

    In the molecular structures of complexes 1 and 2, each nickel(II) ion is six fold coordinated and form a distorted octahedral geometry. ... Department of Chemistry, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502 205, Telangana, India; Department of Applied Chemistry, Indian School ...

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

    Indian Academy of Sciences (India)

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

  6. THE STABILITY CONSTANTS OF NICKEL (II) COMPLEXES OF ...

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... THE STABILITY CONSTANTS OF NICKEL (II) COMPLEXES OF AMINO ACIDS. WITH POLAR UNCHARGED R – GROUPS. Na'aliya, J. Department of Pure and Industrial Chemistry, Bayero University Kano, P. M. B. 3011, Kano, Nigeria jnaaliya@yahoo.com. ABSTRACT. The dissociation constant,pKa of ...

  7. Enhanced personal protection at the PS

    CERN Multimedia

    Samuel Morier Genoud

    2013-01-01

    Pictures 03, 06, 07 08 : Pierre Ninin, deputy group leader of GS-ASE and responsible for the installation of the new PS complex safety system, in front of a new access control system.Pictures 10, 12 ,13 : View of Building 271, the future control centre of the new PS complex safety system.

  8. Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II binary complexes of l-methionine in 1,2-propanediol-water mixtures

    Directory of Open Access Journals (Sweden)

    M. Padma Latha

    2007-04-01

    Full Text Available Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II complexes of L-methionine in 0.0-60 % v/v 1,2-propanediol-water mixtures maintaining an ionic strength of 0.16 M at 303 K has been studied pH metrically. The active forms of ligand are LH2+, LH and L-. The predominant species detected are ML, MLH, ML2, ML2H, ML2H2 and MLOH. Models containing different numbers of species were refined by using the computer program MINIQUAD 75. The best-fit chemical models were arrived at based on statistical parameters. The trend in variation of complex stability constants with change in the dielectric constant of the medium is explained on the basis of electrostatic and non-electrostatic forces.

  9. Nickel (II and Iron (II Complexes with Azole Derivatives: Synthesis, Crystal Structures and Antifungal Activities

    Directory of Open Access Journals (Sweden)

    Emmanuel N. Nfor

    2013-01-01

    Full Text Available Two new complexes of nickel (II with 4-amino-3, 5-bis(pyridyl-1, 2, 4-triazole (abpt and iron (II with 2-(3-phenyl-1H-pyrazole-5-yl pyridine (phpzpy have been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal structures of the complexes have been determined by single crystal X-ray diffraction techniques. In the nickel and iron complexes, the ligands are coordinated through nitrogen atoms in bidentate manner. The ligands and their respective complexes have been tested for their antifungal activity against Aspergillus niger, Aspergillus flavus, and Candida albicans. From the study, the complexes showed enhanced activities against the tested organisms compared to the ligands.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-05-01

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

  11. Speciation of binary complexes of Pb(II) and Cd(II) with L ...

    African Journals Online (AJOL)

    Chemical speciation of L-Asparagine complexes of Pb(II) and Cd(II) in presence of (0-50% v/v) dimethyl sulfoxide(DMSO)-water mixtures has been studied potentiometrically at 303.0 K and at an ionic strength of 0.16 mol L-1. The models containing different number of species were refined by using the computer program ...

  12. SPECIATION OF BINARY COMPLEXES OF Pb(II) AND Cd(II) WITH ...

    African Journals Online (AJOL)

    ABSTRACT. Chemical speciation of L-Asparagine complexes of Pb(II) and Cd(II) in presence of (0-50% v/v) dimethyl sulfoxide(DMSO)-water mixtures has been studied potentiometrically at 303.0 K and at an ionic strength of 0.16 mol L-1. The models containing different number of species were refined by using the ...

  13. Bortezomib (PS-341 treatment decreases inflammation and partially rescues the expression of the dystrophin-glycoprotein complex in GRMD dogs.

    Directory of Open Access Journals (Sweden)

    Karla P C Araujo

    Full Text Available Golden retriever muscular dystrophy (GRMD is a genetic myopathy corresponding to Duchenne muscular dystrophy (DMD in humans. Muscle atrophy is known to be associated with degradation of the dystrophin-glycoprotein complex (DGC via the ubiquitin-proteasome pathway. In the present study, we investigated the effect of bortezomib treatment on the muscle fibers of GRMD dogs. Five GRMD dogs were examined; two were treated (TD- Treated dogs with the proteasome inhibitor bortezomib, and three were control dogs (CD. Dogs were treated with bortezomib using the same treatment regimen used for multiple myeloma. Pharmacodynamics were evaluated by measuring the inhibition of 20S proteasome activity in whole blood after treatment and comparing it to that in CD. We performed immunohistochemical studies on muscle biopsy specimens to evaluate the rescue of dystrophin and dystrophin-associated proteins in the muscles of GRMD dogs treated with bortezomib. Skeletal tissue from TD had lower levels of connective tissue deposition and inflammatory cell infiltration than CD as determined by histology, collagen morphometry and ultrastructural analysis. The CD showed higher expression of phospho-NFκB and TGF-β1, suggesting a more pronounced activation of anti-apoptotic factors and inflammatory molecules and greater connective tissue deposition, respectively. Immunohistochemical analysis demonstrated that dystrophin was not present in the sarcoplasmic membrane of either group. However, bortezomib-TD showed higher expression of α- and β-dystroglycan, indicating an improved disease histopathology phenotype. Significant inhibition of 20S proteasome activity was observed 1 hour after bortezomib administration in the last cycle when the dose was higher. Proteasome inhibitors may thus improve the appearance of GRMD muscle fibers, lessen connective tissue deposition and reduce the infiltration of inflammatory cells. In addition, proteasome inhibitors may rescue some

  14. Multi-Nuclear NMR Investigation of Nickel(II), Palladium(II), Platinum(II) and Ruthenium(II) Complexes of an Asymmetrical Ditertiary Phosphine

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Joe Gerald Jesu [Institut National de la Recherche Scientifique, Quebec (China); Pathak, Devendra Deo [Indian School of Mines, Dhanbad (India); Kapoor, Pramesh N. [Univ. of Delhi, Delhi (India)

    2013-12-15

    Complexes synthesized by reacting alkyl and aryl phosphines with different transition metals are of great interest due to their catalytic properties. Many of the phosphine complexes are soluble in polar solvents as a result they find applications in homogeneous catalysis. In our present work we report, four transition metal complexes of Ni(II), Pd(II), Pt(II) and Ru(II) with an asymmetrical ditertiaryphosphine ligand. The synthesized ligand bears a less electronegative substituent such as methyl group on the aromatic nucleus hence makes it a strong σ-donor to form stable complexes and thus could effectively used in catalytic reactions. The complexes have been completely characterized by elemental analyses, FTIR, {sup 1}HNMR, {sup 31}PNMR and FAB Mass Spectrometry methods. Based on the spectroscopic evidences it has been confirmed that Ni(II), Pd(II) and Pt(II) complexes with the ditertiaryphosphine ligand showed cis whereas the Ru(II) complex showed trans geometry in their molecular structure.

  15. Investigation of the oxygen affinity of manganese(II, cobalt(II and nickel(II complexes with some tetradentate Schiff bases

    Directory of Open Access Journals (Sweden)

    Adel A.A. Emara

    2014-12-01

    Full Text Available Oxygen absorption–desorption processes for square planar Mn(II, Co(II and Mn(II complexes of tetradentate Schiff base ligands in DMF and chloroform solvents were investigated. The tetradentate Schiff base ligands were obtained by condensation reaction of ethylenediamine with salcyldehyde, o-hydroxyacetophenone or acetylacetone in the molar ratio 1:2. The square planar complexes were prepared by the reaction of the Schiff base ligands with Mn(II acetate, Co(II nitrate and Ni(II nitrate in dry ethanol under nitrogen atmosphere. The sorption processes were undertaken in the presence and absence of (pyridine axial-base in 1:1 M ratio of (pyridine:metal(II complexes. Complexes in DMF indicate significant oxygen affinity than in chloroform solvent. Cobalt(II complexes showed significant sorption processes compared to Mn(II and Ni(II complexes. The presence of pyridine axial base clearly increases oxygen affinity.

  16. High molecular weight forms of mammalian respiratory chain complex II.

    Directory of Open Access Journals (Sweden)

    Nikola Kovářová

    Full Text Available Mitochondrial respiratory chain is organised into supramolecular structures that can be preserved in mild detergent solubilisates and resolved by native electrophoretic systems. Supercomplexes of respiratory complexes I, III and IV as well as multimeric forms of ATP synthase are well established. However, the involvement of complex II, linking respiratory chain with tricarboxylic acid cycle, in mitochondrial supercomplexes is questionable. Here we show that digitonin-solubilised complex II quantitatively forms high molecular weight structures (CIIhmw that can be resolved by clear native electrophoresis. CIIhmw structures are enzymatically active and differ in electrophoretic mobility between tissues (500 - over 1000 kDa and cultured cells (400-670 kDa. While their formation is unaffected by isolated defects in other respiratory chain complexes, they are destabilised in mtDNA-depleted, rho0 cells. Molecular interactions responsible for the assembly of CIIhmw are rather weak with the complexes being more stable in tissues than in cultured cells. While electrophoretic studies and immunoprecipitation experiments of CIIhmw do not indicate specific interactions with the respiratory chain complexes I, III or IV or enzymes of the tricarboxylic acid cycle, they point out to a specific interaction between CII and ATP synthase.

  17. Correlated behavior of the EPR signal of cytochrome b-559 heme Fe(III) ligated by OH- and the multiline signal of the Mn cluster in PS-II membrane fragments.

    Science.gov (United States)

    Fiege, R; Shuvalov, V A

    1996-05-27

    EPR signals of Cyt b-559 heme Fe(III) ligated by OH- and the multiline signal of the Mn cluster in PS-II membrane fragments have been investigated. In 2,3-dicyano-5,6-dichloro-p-benzoquinone-oxidized PS-II membrane fragments the light-induced decrease of the EPR signal of the heme Fe(III)-OH- is accompanied by the appearance of the EPR multiline signal of the Mn cluster. Addition of F- ions, which act as a stronger ligand for heme Fe(III) than OH-, decreases to the same extent the dark- and light-induced signal of the heme Fe(III)-OH- and the light-induced multiline signal of the Mn cluster. These results are discussed in terms of the light-induced formation of a bound OH' radical shared between the Cyt b-559 heme Fe and the Mn cluster as a first step of water oxidation.

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

    Science.gov (United States)

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

    2006-03-01

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

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

    Science.gov (United States)

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

    2006-03-01

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

  20. Copper(II) and lead(II) complexation by humic acid and humic-like ligands

    OpenAIRE

    IVANA KOSTIĆ; TATJANA ANĐELKOVIĆ; RUŽICA NIKOLIĆ; ALEKSANDAR BOJIĆ; MILOVAN PURENOVIĆ; SRĐAN BLAGOJEVIĆ; DARKO ANĐELKOVIĆ

    2011-01-01

    The stability of metal–humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II) and Pb(II) with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25 °C and at an ionic strength of 0.01 mol dm-3 (NaCl) using the Schubert ion-exchange method and its modified form....

  1. The Electronic Structure of Mn in Oxides, Coordination Complexes, and the Oxygen-Evolving Complex of Photosystem II Studied by Resonant Inelastic X-ray Scattering

    Science.gov (United States)

    Yano, Junko; Visser, Hendrik; Robblee, John H.; Gu, Weiwei; de Groot, Frank M. F.; Christou, George; Pecoraro, Vincent L.

    2014-01-01

    Resonant inelastic X-ray scattering (RIXS) was used to collect Mn K pre-edge spectra and to study the electronic structure in oxides, molecular coordination complexes, as well as the S1 and S2 states of the oxygen-evolving complex (OEC) of photosystem II (PS II). The RIXS data yield two-dimensional plots that can be interpreted along the incident (absorption) energy or the energy transfer axis. The second energy dimension separates the pre-edge (predominantly 1s to 3d transitions) from the main K-edge, and a detailed analysis is thus possible. The 1s2p RIXS final-state electron configuration along the energy transfer axis is identical to conventional L-edge absorption spectroscopy, and the RIXS spectra are therefore sensitive to the Mn spin state. This new technique thus yields information on the electronic structure that is not accessible in conventional K-edge absorption spectroscopy. The line splittings can be understood within a ligand field multiplet model, i.e., (3d,3d) and (2p,3d) two-electron interactions are crucial to describe the spectral shapes in all systems. We propose to explain the shift of the K pre-edge absorption energy upon Mn oxidation in terms of the effective number of 3d electrons (fractional 3d orbital population). The spectral changes in the Mn 1s2p3/2 RIXS spectra between the PS II S1 and S2 states are small compared to that of the oxides and two of the coordination complexes (MnIII(acac)3 and MnIV(sal)2(bipy)). We conclude that the electron in the step from S1 to S2 is transferred from a strongly delocalized orbital. PMID:15303869

  2. Unsaturated b-ketoesters and their Ni(II, Cu(II and Zn(II complexes

    Directory of Open Access Journals (Sweden)

    MUHAMMED BASHEER UMMATHUR

    2009-03-01

    Full Text Available A new series of b-ketoesters in which the keto group is attached to the olefinic linkage were synthesized by the reaction of methyl acetoacetate and aromatic aldehydes under specified conditions. The existence of these compounds predominantly in the intramolecularly hydrogen bonded enol form was well demonstrated from their IR, 1H-NMR and mass spectral data. Details on the formation of their [ML2] complexes with Ni(II, Cu(II and Zn(II and the nature of the bonding are discussed on the basis of analytical and spectral data.

  3. Synthesis, Characterization, and Biological Activity of Nickel (II and Palladium (II Complex with Pyrrolidine Dithiocarbamate (PDTC

    Directory of Open Access Journals (Sweden)

    Sk Imadul Islam

    2016-01-01

    Full Text Available The synthesis of square planar Ni(II and Pd(II complexes with pyrrolidine dithiocarbamate (PDTC was characterized by elemental, physiochemical, and spectroscopic methods. Two complexes were prepared by the reaction of nickel acetate and palladium acetate with pyrrolidine dithiocarbamate (PDTC in 1 : 2 molar ratio. The bovine serum albumin (BSA interaction with complexes was examined by absorption and fluorescence spectroscopic techniques at pH 7.4. All the spectral data suggest that coordination of the pyrrolidine dithiocarbamate (PDTC takes place through the two sulphur atoms in a symmetrical bidentate fashion. All the synthesized compounds were screened for their antimicrobial activity against some species of pathogenic bacteria (Escherichia coli, Vibrio cholerae, Streptococcus pneumonia, and Bacillus cereus. It has been observed that complexes have higher activity than the free ligand.

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

    Science.gov (United States)

    Mautner, Franz A.; Massoud, Salah S.

    2007-12-01

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

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

    Science.gov (United States)

    Chandra, Usha; Chandra, Sulekh

    1992-08-01

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

  6. Anionic Palladium(0) and Palladium(II) Ate Complexes.

    Science.gov (United States)

    Kolter, Marlene; Böck, Katharina; Karaghiosoff, Konstantin; Koszinowski, Konrad

    2017-10-16

    Palladium ate complexes are frequently invoked as important intermediates in Heck and cross-coupling reactions, but so far have largely eluded characterization at the molecular level. Here, we use electrospray-ionization mass spectrometry, electrical conductivity measurements, and NMR spectroscopy to show that the electron-poor catalyst [L3 Pd] (L=tris[3,5-bis(trifluoromethyl)phenyl]phosphine) readily reacts with Br(-) ions to afford the anionic, zero-valent ate complex [L3 PdBr](-) . In contrast, more-electron-rich Pd catalysts display lower tendencies toward the formation of ate complexes. Combining [L3 Pd] with LiI and an aryl iodide substrate (ArI) results in the observation of the Pd(II) ate complex [L2 Pd(Ar)I2 ](-) . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The Basic Properties of the Electronic Structure of the Oxygen-evolving Complex of Photosystem II Are Not Perturbed by Ca2+ Removal*

    Science.gov (United States)

    Lohmiller, Thomas; Cox, Nicholas; Su, Ji-Hu; Messinger, Johannes; Lubitz, Wolfgang

    2012-01-01

    Ca2+ is an integral component of the Mn4O5Ca cluster of the oxygen-evolving complex in photosystem II (PS II). Its removal leads to the loss of the water oxidizing functionality. The S2′ state of the Ca2+-depleted cluster from spinach is examined by X- and Q-band EPR and 55Mn electron nuclear double resonance (ENDOR) spectroscopy. Spectral simulations demonstrate that upon Ca2+ removal, its electronic structure remains essentially unaltered, i.e. that of a manganese tetramer. No redistribution of the manganese valence states and only minor perturbation of the exchange interactions between the manganese ions were found. Interestingly, the S2′ state in spinach PS II is very similar to the native S2 state of Thermosynechococcus elongatus in terms of spin state energies and insensitivity to methanol addition. These results assign the Ca2+ a functional as opposed to a structural role in water splitting catalysis, such as (i) being essential for efficient proton-coupled electron transfer between YZ and the manganese cluster and/or (ii) providing an initial binding site for substrate water. Additionally, a novel 55Mn2+ signal, detected by Q-band pulse EPR and ENDOR, was observed in Ca2+-depleted PS II. Mn2+ titration, monitored by 55Mn ENDOR, revealed a specific Mn2+ binding site with a submicromolar KD. Ca2+ titration of Mn2+-loaded, Ca2+-depleted PS II demonstrated that the site is reversibly made accessible to Mn2+ by Ca2+ depletion and reconstitution. Mn2+ is proposed to bind at one of the extrinsic subunits. This process is possibly relevant for the formation of the Mn4O5Ca cluster during photoassembly and/or D1 repair. PMID:22549771

  8. The basic properties of the electronic structure of the oxygen-evolving complex of photosystem II are not perturbed by Ca2+ removal.

    Science.gov (United States)

    Lohmiller, Thomas; Cox, Nicholas; Su, Ji-Hu; Messinger, Johannes; Lubitz, Wolfgang

    2012-07-13

    Ca(2+) is an integral component of the Mn(4)O(5)Ca cluster of the oxygen-evolving complex in photosystem II (PS II). Its removal leads to the loss of the water oxidizing functionality. The S(2)' state of the Ca(2+)-depleted cluster from spinach is examined by X- and Q-band EPR and (55)Mn electron nuclear double resonance (ENDOR) spectroscopy. Spectral simulations demonstrate that upon Ca(2+) removal, its electronic structure remains essentially unaltered, i.e. that of a manganese tetramer. No redistribution of the manganese valence states and only minor perturbation of the exchange interactions between the manganese ions were found. Interestingly, the S(2)' state in spinach PS II is very similar to the native S(2) state of Thermosynechococcus elongatus in terms of spin state energies and insensitivity to methanol addition. These results assign the Ca(2+) a functional as opposed to a structural role in water splitting catalysis, such as (i) being essential for efficient proton-coupled electron transfer between Y(Z) and the manganese cluster and/or (ii) providing an initial binding site for substrate water. Additionally, a novel (55)Mn(2+) signal, detected by Q-band pulse EPR and ENDOR, was observed in Ca(2+)-depleted PS II. Mn(2+) titration, monitored by (55)Mn ENDOR, revealed a specific Mn(2+) binding site with a submicromolar K(D). Ca(2+) titration of Mn(2+)-loaded, Ca(2+)-depleted PS II demonstrated that the site is reversibly made accessible to Mn(2+) by Ca(2+) depletion and reconstitution. Mn(2+) is proposed to bind at one of the extrinsic subunits. This process is possibly relevant for the formation of the Mn(4)O(5)Ca cluster during photoassembly and/or D1 repair.

  9. Biphenolate Iron (II) Complexes with Intramolecularly Coordinating Nitrogen Lewis Bases

    NARCIS (Netherlands)

    Koten, G. van; Brandts, J.A.M.; Janssen, M.D.; Hogerheide, M.P.; Boersma, J.; Spek, A.L.

    1999-01-01

    The synthesis and characterisation of a novel Fe(II) bisphenolate complex [Fe(OC{6}H{4}CH{2}NMe{2}-2){2}]{2} (1) from [Na(OC{6}H{4}CH{2}NMe{2}-2)] and anhydrous FeCl{2} is reported. The solid state structure has been elucidated by single crystal X-ray analysis and shows a dimeric structure with two

  10. The quinone-binding and catalytic site of complex II.

    Science.gov (United States)

    Maklashina, Elena; Cecchini, Gary

    2010-12-01

    The complex II family of proteins includes succinate:quinone oxidoreductase (SQR) and quinol:fumarate oxidoreductase (QFR). In the facultative bacterium Escherichia coli both are expressed as part of the aerobic (SQR) and anaerobic (QFR) respiratory chains. SQR from E. coli is homologous to mitochondrial complex II and has proven to be an excellent model system for structure/function studies of the enzyme. Both SQR and QFR from E. coli are tetrameric membrane-bound enzymes that couple succinate/fumarate interconversion with quinone/quinol reduction/oxidation. Both enzymes are capable of binding either ubiquinone or menaquinone, however, they have adopted different quinone binding sites where catalytic reactions with quinones occur. A comparison of the structures of the quinone binding sites in SQR and QFR reveals how the enzymes have adapted in order to accommodate both benzo- and napthoquinones. A combination of structural, computational, and kinetic studies of members of the complex II family of enzymes has revealed that the catalytic quinone adopts different positions in the quinone-binding pocket. These data suggest that movement of the quinone within the quinone-binding pocket is essential for catalysis. Published by Elsevier B.V.

  11. Synthesis, spectroscopic, antimicrobial and DNA cleavage studies of new Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and Hg(II) complexes with naphthofuran-2-carbohydrazide Schiff base

    Science.gov (United States)

    Halli, Madappa B.; Sumathi, R. B.

    2012-08-01

    A series of Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and Hg(II) complexes have been synthesized with newly synthesized Schiff base derived from naphthofuran-2-carbohydrazide and cinnamaldehyde. The elemental analyses of the complexes are confined to the stoichiometry of the type MLCl2 [M = Co(II) and Cu(II)], ML2Cl2 [M = Ni(II), Cd(II), Zn(II) and Hg(II)] respectively, where L is Schiff base ligand. Structures have been proposed from elemental analyses, IR, electronic, mass, 1H NMR, ESR spectral data, magnetic, and thermal studies. The measured low molar conductance values in DMF indicate that the complexes are non-electrolytes. Spectroscopic studies suggest coordination occurs through azomethine nitrogen and carbonyl oxygen of the ligand with the metal ions. The Schiff base and its complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi) and antifungal (Aspergillus niger, Aspergillus flavus, Cladosporium and Candida albicans) activities by minimum inhibitory concentration (MIC) method. The DNA cleavage studies by agarose gel electrophoresis method was studied for all the complexes.

  12. Synthesis, Characterization, and Antibacterial Activity of Co(II, Ni(II, Cu(II, Zn(II, Cd(II, and Hg(II Complexes of Schiff's Base Type Ligands Containing Benzofuran Moiety

    Directory of Open Access Journals (Sweden)

    N. Shashidhar Reddy

    2013-01-01

    Full Text Available Six new complexes of Co(II, Ni(II, Cu(II, Zn(II, Cd(II, and Hg(II with substituted benzofuran derivatives have been synthesized and characterized by elemental analysis, magnetic moments, conductance measurements, spectral characterization, and so forth. Elemental data coincide with the general formula MLC1n, where L = (E-7-Methoxy-N1-(2,4,5-trimethoxy benzylidene benzofuran-2-carbohydrazide (L1 or (E-N1-(2,6-dichloro benzylidene-7-methoxy benzofuran-2-carbohydrazide (L2, of the complexes. The ligands coordinate to the metal ions through the oxygen of the carbonyl group and the nitrogen of the hydrazine group. Electronic spectral data of the complexes suggests the probable geometry is octahedral in nature. All the complexes and ligands were screened for their antibacterial activity. Among them, Co, Ni, and Cu complexes of L2 showed good activity against all microbes.

  13. One-dimensional Co(II)/Ni(II) complexes of 2-hydroxyisophthalate: Structures and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kai [Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China); State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004 (China); Zou, Hua-Hong; Chen, Zi-Lu; Zhang, Zhong [State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004 (China); Sun, Wei-Yin [Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China); Liang, Fu-Pei, E-mail: fliangoffice@yahoo.com [State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004 (China); College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004 (China)

    2015-03-15

    The solvothermal reactions of 2-hydroxyisophthalic acid (H{sub 3}ipO) with M(NO{sub 3}){sub 2}∙6H{sub 2}O (M=Co, Ni) afforded two complexes [Co{sub 2}(HipO){sub 2}(Py){sub 2}(H{sub 2}O){sub 2}] (1) and [Ni(HipO)(Py)H{sub 2}O] (2) (Py=pyridine). They exhibit similar zig-zag chain structures with the adjacent two metal centers connected by a anti-syn bridging carboxylate group from the HipO{sup 2−} ligand. The magnetic measurements reveal the dominant antiferromagnetic interactions and spin-canting in 1 while ferromagnetic interactions in 2. Both of them exhibit magnetocaloric effect (MCE) with the resulting entropy changes (−ΔS{sub m}) of 12.51 J kg{sup −1} K{sup −1} when ΔH=50 kOe at 3 K for 1 and 11.01 J kg{sup −1} K{sup −1} when ΔH=50 kOe at 3 K for 2, representing the rare examples of one-dimensional complexes with MCE. - Graphical abstract: Synopsis: Two Co(II)/Ni(II) complexes with zig-zag chain structures have been reported. 1-Co shows cant-antiferromagnetism while 2-Ni shows ferromagnetism. Magnetocaloric effect is also found in both of them. - Highlights: • Two one-dimensional Co(II)/Ni(II) complexes were solvothermally synthesized. • The Co-complex exhibits canted antiferromagnetism. • The Ni-complex exhibits ferromagnetism. • Both of the complexes display magnetocaloric effect.

  14. Synthesis, spectral characterization and biological evaluation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with thiosemicarbazone ending by pyrazole and pyridyl rings

    Science.gov (United States)

    Yousef, T. A.; Abu El-Reash, G. M.; Al-Jahdali, M.; El-Rakhawy, El-Bastawesy R.

    2014-08-01

    Here we present the synthesis of the new Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with chelating ligand (Z)-(2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene) hydrazinyl)(pyridin-2-ylamino)methanethiol. All the complexes were characterized by elemental analysis, IR, 1H NMR, UV-vis, magnetic susceptibility measurements and EPR spectral studies. IR spectra of complexes showed that the ligand behaves as NN neutral bidentate, NSN mononegative tridentate and NSNN mononegative tetradentate. The electronic spectra and the magnetic measurements suggested the octahedral geometry for all complexes as well as the EPR confirmed the tetragonal distorted octahedral for Cu(II) complex. Cd(II) complex showed the highest inhibitory antioxidant activity either using ABTS method. The SOD-like activity exhibited those Cd(II) and Zn(II) complexes have strong antioxidative properties. We tested the synthesized compounds for antitumor activity and showed that the ability to kill liver (HePG2) and breast (MCF-7) cancer cells definitely.

  15. Antiviral Activity of Substituted Chalcones and their Respective Cu(ii, Ni(ii and Zn(ii Complexes

    Directory of Open Access Journals (Sweden)

    K. G. Mallikarjun

    2005-01-01

    Full Text Available Complexes of Cu(II, Ni(II and Zn(II with of 3-(phenyl-1-(2’-hydroxynaphthyl – 2 – propen – 1 – one (PHPO , 3 - (4-chlorophenyl - 1- (2’-hydroxynaphthyl–2–propen – 1 – one (CPHPO, 3 - (4 -methoxyphenyl -1-(2’-hydroxynapthyl-2-propen-1-one(MPHPO,3 - (3,4-dimethoxyphenyl –1-(2’-hydroxynaphthyl – 2 - propen– 1 – one (DMPHPO have been prepared and the purity of the samples were checked by elemental analysis. The ligands and their Cu(II, Ni(II and Zn(II complexes were tested on the infectivity of tobacco ring spot virus(TRSV using cowpea (Vigna Sinensis as a local lesions assay host. All the compounds were tested at different concentrations (250 ppm to 1500 ppmon the infectivity of the virus by applying them either with virus inoculum or 24 h before of after virus inoculation to the test plants. The compounds were found to have varied effects on virus infectivity depending on compounds concentration and method of application. The statistical significance of the data was determined by using analysis of variance.

  16. Synthesis, structure, and paramagnetism of manganese(II) iminophosphate complexes.

    Science.gov (United States)

    Woodruff, Daniel N; McInnes, Eric J L; Sells, Daniel O; Winpenny, Richard E P; Layfield, Richard A

    2012-08-20

    The coordination chemistry of the bidentate bis(imino)bis(amino)phosphate ligands [Me(3)SiN═P{NR}{N(H)R}(2)](-), where R = n-propyl is [L(1)H(2)](-), R = cyclohexyl is [L(2)H(2)](-), and R = tert-butyl is [L(3)H(2)](-), with manganese(II), is described. The bis(imino)bis(amino)phosphate-manganese(II) complexes [(η(5)-Cp)Mn(μ-L(1)H(2))](2) (1), [Mn(L(2)H(2))(2)]·THF (2·THF), and [(η(5)-Cp)Mn(L(3)H(2))] (3) were synthesized by monodeprotonation of the respective pro-ligands by manganocene, Cp(2)Mn. The molecular structures of 1-3 reveal that the steric demands of the ligand N-substituents play a dominant role in determining the aggregation state and overall composition of the manganese(II) complexes. The coordination geometries of the Mn(II) centers are six-coordinate pseudotetrahedral in 1, four-coordinate distorted tetrahedral in 2, and five-coordinate in 3, resulting in formal valence electron counts of 17, 13, and 15, respectively. EPR studies of 1-3 at Q-band reveal high-spin manganese(II) (S = 5/2) in each case. In the EPR spectrum of 1, no evidence of intramolecular magnetic exchange was found. The relative magnitudes of the axial zero-field splitting parameter, D, in 2 and 3 are consistent with the symmetry of the manganese environment, which are D(2d) in 2 and C(2v) in 3.

  17. Complexes cobalt(II, zinc(II and copper(II with some newly synthesized benzimidazole derivatives and their antibacterial activity

    Directory of Open Access Journals (Sweden)

    S. O. PODUNAVAC-KUZMANOVIC

    1999-05-01

    Full Text Available The preparation and properties of some complexes of cobalt(II, zinc(II and copper(II with several newly synthesized benzimidazole derivatives (L are reported. The complexes, of the general formula [MCl2L2] (M=Co(II, Zn(II and [CuCl2L(H2O], have a tetrahedral structure. The complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility measurements, IR and absorption electronic spectra. The antibacterial activitiy of the benzimidazoles and their complexes was evaluated against Erwinia carotovora subsp. carotovora and Erwinia amylovora. The complexes were found to be more toxic than the ligands.

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

    Science.gov (United States)

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

    2012-07-01

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

  19. Ruthenium(II) Complex Based Photodiode for Organic Electronic Applications

    Science.gov (United States)

    Tataroglu, A.; Ocaya, R.; Dere, A.; Dayan, O.; Serbetci, Z.; Al-Sehemi, Abdullah G.; Soylu, M.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

    2018-01-01

    In this study, the electrical and photoresponse properties of a photovoltaic device with Ruthenium(II) complex interfacial thin film were investigated. Heteroleptic Ru(II) complex including bidentate and tridentate ligands thin film was coated on n-Si substrate by the spin coating technique. From current-voltage ( I- V) measurements of an Au/Ru(II)/n-Si photodiode, it is observed that the reverse bias current under light is higher than that of the current in the dark. This indicates that the photodiode exhibits a photoconducting characteristic. The transient measurements such as photocurrent, photocapacitance and photoconductance were performed under various illumination conditions. These measurements indicate that the photodiode has a high photoresponsivity. The electrical parameters such as barrier height (Φb), ideality factor ( n) and series resistance ( R s) of the photodiode were determined from the analysis of I- V characteristics. Moreover, the capacitance/conductance-voltage characteristics of the photodiode highly depend on both voltage and frequency. Results show that the heterojunction can be used for various optoelectronic applications.

  20. Ruthenium(II) Complex Based Photodiode for Organic Electronic Applications

    Science.gov (United States)

    Tataroglu, A.; Ocaya, R.; Dere, A.; Dayan, O.; Serbetci, Z.; Al-Sehemi, Abdullah G.; Soylu, M.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

    2017-10-01

    In this study, the electrical and photoresponse properties of a photovoltaic device with Ruthenium(II) complex interfacial thin film were investigated. Heteroleptic Ru(II) complex including bidentate and tridentate ligands thin film was coated on n-Si substrate by the spin coating technique. From current-voltage (I-V) measurements of an Au/Ru(II)/n-Si photodiode, it is observed that the reverse bias current under light is higher than that of the current in the dark. This indicates that the photodiode exhibits a photoconducting characteristic. The transient measurements such as photocurrent, photocapacitance and photoconductance were performed under various illumination conditions. These measurements indicate that the photodiode has a high photoresponsivity. The electrical parameters such as barrier height (Φb), ideality factor (n) and series resistance (R s) of the photodiode were determined from the analysis of I-V characteristics. Moreover, the capacitance/conductance-voltage characteristics of the photodiode highly depend on both voltage and frequency. Results show that the heterojunction can be used for various optoelectronic applications.

  1. Nickel(II) and palladium(II) complexes of azobenzene-containing ligands as dichroic dyes.

    Science.gov (United States)

    Blackburn, Octavia A; Coe, Benjamin J; Fielden, John; Helliwell, Madeleine; McDouall, Joseph J W; Hutchings, Michael G

    2010-10-18

    A large series of complexes has been synthesized with two chelating, Schiff base azobenzene derivatives connected linearly by coordination to a central nickel(II) or palladium(II) ion. These compounds have the general formulas M(II)(OC(6)H(3)-2-CHNR-4-N═NC(6)H(4)-4-CO(2)Et)(2) [M = Ni; R = n-Bu (3c), n-C(6)H(13) (3d), n-C(8)H(17) (3e), n-C(12)H(25) (3f), Ph (3g), OH (3h), C(6)H(4)-4-CO(2)Et (3i). M = Pd; R = i-Pr (4a), t-Bu (4b), n-Bu (4c), n-C(6)H(13) (4d), n-C(8)H(17) (4e), n-C(12)H(25) (4f), Ph (4g)], M(II)[OC(6)H(3)-2-CHN(n-C(8)H(17))-4-N═NC(6)H(4)-4-CO(2)(n-C(8)H(17))](2) [M = Ni (9), Pd (10)], M(II)[OC(6)H(3)-2-CHN(n-C(8)H(17))-4-N═NC(6)H(4)-4-C(6)H(4)-4-O(n-C(7)H(15))](2) [M = Ni (14), Pd (15)], and M(II)[OC(6)H(3)-2-CHN(CMe(2))-4-N═NC(6)H(4)-4-CO(2)Et](2) [M = Ni (17), Pd (18); the CMe(2) groups are connected]. These compounds have been characterized by using various physical techniques including (1)H NMR spectroscopy and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Single-crystal X-ray structures have been obtained for two pro-ligands and five complexes (3e, 4e, 14, 15, and 17). The latter always show a strictly square planar arrangement about the metal center, except for the Ni(II) complex of a salen-like ligand (17). In solution, broadened (1)H NMR signals indicate distortions from square planar geometry for the bis-chelate Ni(II) complexes. Electronic absorption spectroscopy and ZINDO_S (Zerner's intermediate neglect of differential overlap) and TD-DFT (time-dependent density functional theory) calculations show that the lowest energy transition has metal-to-ligand charge-transfer character. The λ(max) of this band lies in the range of 409-434 nm in dichloromethane, and replacing Ni(II) with Pd(II) causes small blue-shifts. Dichroic ratios measured in various liquid crystal hosts show complexation-induced increases with Ni(II), but using Pd(II) has a detrimental effect.

  2. Spectroscopic and biological approach of Ni(II) and Cu(II) complexes of 2-pyridinecarboxaldehyde thiosemicarbazone

    Science.gov (United States)

    Chandra, Sulekh; Raizada, Smriti; Tyagi, Monika; Sharma, Praveen Kumar

    2008-03-01

    Ni(II) and Cu(II) complexes having the general composition [M(L) 2X 2] [where L = 2-pyridinecarboxaldehyde thiosemicarbazone, M = Ni(II) and Cu(II), X = Cl -, NO 3- and 1/2 SO 42-] have been synthesized. All the metal complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, EPR and electronic spectral studies. The magnetic moment measurements of the complexes indicate that all the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry has been assigned for Ni(II) complexes whereas tetragonal geometry for Cu(II) except [Cu(L) 2SO 4] which posseses five coordinated geometry. The ligand and its metal complexes were screened against phytopathogenic fungi and bacteria in vitro.

  3. Electrochemical studies of DNA interaction and antimicrobial activities of MnII, FeIII, CoII and NiII Schiff base tetraazamacrocyclic complexes

    Science.gov (United States)

    Kumar, Anuj; Vashistha, Vinod Kumar; Tevatia, Prashant; Singh, Randhir

    2017-04-01

    Tetraazamacrocyclic complexes of MnII, FeIII, CoII and NiII have been synthesized by template method. These tetraazamacrocycles have been analyzed with various techniques like molar conductance, IR, UV-vis, mass spectral and cyclic voltammetric studies. On the basis of all these studies, octahedral geometry has been assigned to these tetraazamacrocyclic complexes. The DNA binding properties of these macrocyclic complexes have been investigated by electronic absorption spectra, fluorescence spectra, cyclic voltammetric and differential pulse voltammetric studies. The cyclic voltammetric data showed that ipc and ipa were effectively decreased in the presence of calf thymus DNA, which is a strong evidence for the interaction of these macrocyclic complexes with the calf thymus DNA (ct-DNA). The heterogeneous electron transfer rate constant found in the order: KCoII > KNiII > KMnII which indicates that CoII macrocyclic complex has formed a strong intercalated intermediate. The Stern-Volmer quenching constant (KSV) and voltammetric binding constant were found in the order KSV(CoII) > KSV(NiII) > KSV(MnII) and K+(CoII) > K+(NiII) > K+(MnII) which shows that CoII macrocyclic complex exhibits the high interaction affinity towards ct-DNA by the intercalation binding. Biological studies of the macrocyclic complexes compared with the standard drug like Gentamycin, have shown antibacterial activities against E. coli, P. aeruginosa, B. cereus, S. aureus and antifungal activity against C. albicans.

  4. DNA photocleavage by a supramolecular Ru(II)-viologen complex.

    Science.gov (United States)

    Fu, Patty K-L; Bradley, Patricia M; van Loyen, Dietmar; Dürr, Heinz; Bossmann, Stefan H; Turro, Claudia

    2002-07-29

    A novel Ru(II) complex possessing two sequentially linked viologen units, Ru-V(1)-V(2)(6+), was synthesized and characterized. Upon excitation of the Ru(II) unit (lambda(exc) = 532 nm, fwhm approximately 10 ns), a long-lived charge-separated (CS) state is observed (tau = 1.7 micros) by transient absorption spectroscopy. Unlike Ru(bpy)(3)(2+), which cleaves DNA upon photolysis through the formation of reactive oxygen species, such as (1)O(2) and O(2)(-), the photocleavage of plasmid DNA by Ru-V(1)-V(2)(6+) is observed both in air and under N(2) atmosphere (lambda(irr) > 395 nm).

  5. Anticancer Activities of Mononuclear Ruthenium(II Coordination Complexes

    Directory of Open Access Journals (Sweden)

    William M. Motswainyana

    2015-01-01

    Full Text Available Ruthenium compounds are highly regarded as potential drug candidates. The compounds offer the potential of reduced toxicity and can be tolerated in vivo. The various oxidation states, different mechanism of action, and the ligand substitution kinetics of ruthenium compounds give them advantages over platinum-based complexes, thereby making them suitable for use in biological applications. Several studies have focused attention on the interaction between active ruthenium complexes and their possible biological targets. In this paper, we review several ruthenium compounds which reportedly possess promising cytotoxic profiles: from the discovery of highly active compounds imidazolium [trans-tetrachloro(dmso(imidazoleruthenate(III] (NAMI-A, indazolium [trans-tetrachlorobis(1H-indazoleruthenate(III](KP1019, and sodium trans-[tetrachloridobis(1H-indazoleruthenate(III] (NKP-1339 to the recent work based on both inorganic and organometallic ruthenium(II compounds. Half-sandwich organometallic ruthenium complexes offer the opportunity of derivatization at the arene moiety, while the three remaining coordination sites on the metal centre can be functionalised with various coordination groups of various monoligands. It is clear from the review that these mononuclear ruthenium(II compounds represent a strongly emerging field of research that will soon culminate into several ruthenium based antitumor agents.

  6. Platinum(II) complexes as spectroscopic probes for biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.

    1990-09-21

    The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

  7. Functional properties of the oxygen evolving complex of photosystem 2

    NARCIS (Netherlands)

    Vliet, van P.H.

    1996-01-01


    This Thesis presents the results of a study by electron paramagnetic resonance (EPR) and measurements of oxygen evolution of the Oxygen Evolving Complex of Photosystem 11 (PS-II) in PS-II enriched membranes from spinach.

    The experimental part of this Thesis is preceded by a

  8. Thermodynamics for complex formation between palladium(ii) and oxalate.

    Science.gov (United States)

    Pilný, Radomír; Lubal, Přemysl; Elding, Lars I

    2014-08-28

    Complex formation between [Pd(H2O)4](2+) and oxalate (ox = C2O4(2-)) has been studied spectrophoto-metrically in aqueous solution at variable temperature, ionic strength and pH. Thermodynamic parameters at 298.2 K and 1.00 mol dm(-3) HClO4 ionic medium for the complex formation [Pd(H2O)4](2+) + H2ox ⇄ [Pd(H2O)2(ox)] + 2H3O(+) with equilibrium constant K1,H (in mol dm(-3)) are log10K1,H = 3.38 ± 0.08, ΔH = -33 ± 3 kJ mol(-1), and ΔS = -48 ± 11 J K(-1) mol(-1), as determined from spectrophotometric equilibrium titrations at 15.0, 20.0, 25.0 and 31.0 °C. Thermodynamic overall stability constants β (in (mol dm(-3))(-n), n = 1,2) for [Pd(H2O)2(ox)] and [Pd(ox)2](2-) at zero ionic strength and 298.2 K, defined as the equilibrium constants for the reaction Pd(2+) + nox(2-) ⇄ [Pd(ox)n](2-2n) (water molecules omitted) are log10β = 9.04 ± 0.06 and log10β = 13.1 ± 0.3, respectively, calculated by use of Specific Ion Interaction Theory from spectrophotometric titrations with initial hydrogen ion concentrations of 1.00, 0.100 and 0.0100 mol dm(-3) and ionic strengths of 1.00, 2.00 or 3.00 mol dm(-3). The values derived together with literature data give estimated overall stability constants for Pd(ii) compounds such as [Pd(en)(ox)] and cis-[Pd(NH3)2Cl2], some of them analogs to Pt(ii) complexes used in cancer treatment. The palladium oxalato complexes are significantly more stable than palladium(ii) complexes with monodentate O-bonding ligands. A comparison between several different palladium complexes shows that different parameters contribute to the stability variations observed. These are discussed together with the so-called chelate effect.

  9. PT (II AND PD (II COMPLEXES INFLUENCE ON SPHEROIDS GROWTH OF BREAST CANCER CELLS

    Directory of Open Access Journals (Sweden)

    A. A. Bilyuk

    2017-02-01

    Full Text Available The aim of the research was to examine the changes in multi-cellular tumor spheroid growth, adhesion properties and gamma-glutamintranspeptidasic activity in model systems of human breast cancer multicellular spheroid MCF-7 under the influence of Pt(ІІ and Pd(ІІ π-complexes with allyl-containing thioureas. Comparing with cisplatin, Pt(II and Pd(II complexes reduce gamma-glutamintranspeptidasic activity, increase adhesive properties in model system of solid tumor and inhibit the multicellular spheroids’ growth. All changes prove the importance of further investigation and analysis of these compounds as potential analogues of anticancer drugs that possibly do not cause resistance and reduce the level of metastasis in breast cancer.

  10. Interfacial charge separation and recombination in InP and quasi-type II InP/CdS core/shell quantum dot-molecular acceptor complexes.

    Science.gov (United States)

    Wu, Kaifeng; Song, Nianhui; Liu, Zheng; Zhu, Haiming; Rodríguez-Córdoba, William; Lian, Tianquan

    2013-08-15

    Recent studies of group II-VI colloidal semiconductor heterostuctures, such as CdSe/CdS core/shell quantum dots (QDs) or dot-in-rod nanorods, show that type II and quasi-type II band alignment can facilitate electron transfer and slow down charge recombination in QD-molecular electron acceptor complexes. To explore the general applicability of this wave function engineering approach for controlling charge transfer properties, we investigate exciton relaxation and dissociation dynamics in InP (a group III-V semiconductor) and InP/CdS core/shell (a heterostructure beween group III-V and II-VI semiconductors) QDs by transient absorption spectroscopy. We show that InP/CdS QDs exhibit a quasi-type II band alignment with the 1S electron delocalized throughout the core and shell and the 1S hole confined in the InP core. In InP-methylviologen (MV(2+)) complexes, excitons in the QD can be dissociated by ultrafast electron transfer to MV(2+) from the 1S electron level (with an average time constant of 11.4 ps) as well as 1P and higher electron levels (with a time constant of 0.39 ps), which is followed by charge recombination to regenerate the complex in its ground state (with an average time constant of 47.1 ns). In comparison, InP/CdS-MV(2+) complexes show similar ultrafast charge separation and 5-fold slower charge recombination rates, consistent with the quasi-type II band alignment in these heterostructures. This result demonstrates that wave function engineering in nanoheterostructures of group III-V and II-VI semiconductors provides a promising approach for optimizing their light harvesting and charge separation for solar energy conversion applications.

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

    Indian Academy of Sciences (India)

    Administrator

    phenyl)-. 1-phenyl-5-(phenyl-methylene)-2-naphthalenecarboxamide (X = H, CH3, OCH3. Cl)] have been prepared and characterized on the basis of elemental analysis, magnetic moments, i.e., EPR and electronic spectra. These metal complexes ...

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

    Science.gov (United States)

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

    2014-06-02

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

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

    Indian Academy of Sciences (India)

    Administrator

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

  14. Electrophilic alkylation of pseudotetrahedral nickel(II) arylthiolate complexes.

    Science.gov (United States)

    Deb, Tapash; Jensen, Michael P

    2015-01-05

    A kinetic study is reported for reactions of pseudotetrahedral nickel(II) arylthiolate complexes [(Tp(R,Me))Ni-SAr] (Tp(R,Me) = hydrotris{3-R-5-methyl-1-pyrazolyl}borate, R = Me, Ph, and Ar = C6H5, C6H4-4-Cl, C6H4-4-Me, C6H4-4-OMe, 2,4,6-Me3C6H2, 2,4,6-(i)Pr3C6H2) with organic electrophiles R'X (i.e., MeI, EtI, BzBr) in low-polarity organic solvents (toluene, THF, chloroform, dichloromethane, or 1,2-dichloroethane), yielding a pseudotetrahedral halide complex [(Tp(R,Me))Ni-X] (X = Cl, Br, I) and the corresponding organosulfide R'SAr. Competitive reactions with halogenated solvents and adventitious air were also examined. Akin to reactions of analogous and biomimetic zinc complexes, a pertinent mechanistic question is the nature of the reactive nucleophile, either an intact thiolate complex or a free arylthiolate resulting from a dissociative pre-equilibrium. The observed kinetics conformed to a second-order rate law, first order with respect to the complex and electrophile, and no intermediate complexes were observed. In the absence of a mechanistically diagnostic rate law, a variety of mechanistic probes were examined, including kinetic effects of varying the metal, solvent, electrophile, and temperature, as well as the 3-pyrazolyl and arylthiolate substituents. Compared to zinc analogues, the effect of Ni-SAr covalency is also of interest herein. The results are broadly interpreted with respect to the disparate mechanistic pathways.

  15. Synthesis, characterization and single crystal x-ray analysis of a complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sandeep; Andotra, Savit; Kaur, Mandeep [University of Jammu, Department of Chemistry (India); Gupta, Vivek K.; Kant, Rajni [Department of Physics and Electronics, University of Jammu, X-ray Crystallographic Laboratory (India); Pandey, Sushil K., E-mail: kpsushil@rediffmail.com [University of Jammu, Department of Chemistry (India)

    2016-09-15

    Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [((2,4- (CH{sub 3}){sub 2}C{sub 6}H{sub 3}O)2PS2)2Fe(NC{sub 5}H{sub 4}(C{sub 2}H{sub 5})-4){sub 2}] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P2{sub 1}/n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry.

  16. Assembly and properties of heterobimetallic Co(II/III)/Ca(II) complexes with aquo and hydroxo ligands.

    Science.gov (United States)

    Lacy, David C; Park, Young Jun; Ziller, Joseph W; Yano, Junko; Borovik, A S

    2012-10-24

    The use of water as a reagent in redox-driven reactions is advantageous because it is abundant and environmentally compatible. The conversion of water to dioxygen in photosynthesis illustrates one example, in which a redox-inactive Ca(II) ion and four manganese ions are required for function. In this report we describe the stepwise formation of two new heterobimetallic complexes containing Co(II/III) and Ca(II) ions and either hydroxo or aquo ligands. The preparation of a four-coordinate Co(II) synthon was achieved with the tripodal ligand, N,N',N"-[2,2',2"-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamido, [MST](3-). Water binds to [Co(II)MST](-) to form the five-coordinate [Co(II)MST(OH(2))](-) complex that was used to prepare the Co(II)/Ca(II) complex [Co(II)MST(μ-OH(2))Ca(II)⊂15-crown-5(OH(2))](+) ([Co(II)(μ-OH(2))Ca(II)OH(2)](+)). [Co(II)(μ-OH(2))CaOH(2)](+) contained two aquo ligands, one bonded to the Ca(II) ion and one bridging between the two metal ions, and thus represents an unusual example of a heterobimetallic complex containing two aquo ligands spanning different metal ions. Both aquo ligands formed intramolecular hydrogen bonds with the [MST](3-) ligand. [Co(II)MST(OH(2))](-) was oxidized to form [Co(III)MST(OH(2))] that was further converted to [Co(III)MST(μ-OH)Ca(II)⊂15-crown-5](+) ([Co(III)(μ-OH)Ca(II)](+)) in the presence of base and Ca(II)OTf(2)/15-crown-5. [Co(III)(μ-OH)Ca(II)](+) was also synthesized from the oxidation of [Co(II)MST](-) with iodosylbenzene (PhIO) in the presence of Ca(II)OTf(2)/15-crown-5. Allowing [Co(III)(μ-OH)Ca(II)](+) to react with diphenylhydrazine afforded [Co(II)(μ-OH(2))Ca(II)OH(2)](+) and azobenzene. Additionally, the characterization of [Co(III)(μ-OH)Ca(II)](+) provides another formulation for the previously reported Co(IV)-oxo complex, [(TMG(3)tren)Co(IV)(μ-O)Sc(III)(OTf)(3)](2+) to one that instead could contain a Co(III)-OH unit.

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

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, H.; Hirobe, M.

    1986-05-29

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

  18. Neuroprotective Effects and Mechanisms of Curcumin–Cu(II and –Zn(II Complexes Systems and Their Pharmacological Implications

    Directory of Open Access Journals (Sweden)

    Fa-Shun Yan

    2017-12-01

    Full Text Available Alzheimer’s disease (AD is the main form of dementia and has a steadily increasing prevalence. As both oxidative stress and metal homeostasis are involved in the pathogenesis of AD, it would be interesting to develop a dual function agent, targeting the two factors. Curcumin, a natural compound isolated from the rhizome of Curcuma longa, is an antioxidant and can also chelate metal ions. Whether the complexes of curcumin with metal ions possess neuroprotective effects has not been evaluated. Therefore, the present study was designed to investigate the protective effects of the complexes of curcumin with Cu(II or Zn(II on hydrogen peroxide (H2O2-induced injury and the underlying molecular mechanisms. The use of rat pheochromocytoma (PC12 cells, a widely used neuronal cell model system, was adopted. It was revealed that curcumin–Cu(II complexes systems possessed enhanced O2·–-scavenging activities compared to unchelated curcumin. In comparison with unchelated curcumin, the protective effects of curcumin–Cu(II complexes systems were stronger than curcumin–Zn(II system. Curcumin–Cu(II or –Zn(II complexes systems significantly enhanced the superoxide dismutase, catalase, and glutathione peroxidase activities and attenuated the increase of malondialdehyde levels and caspase-3 and caspase-9 activities, in a dose-dependent manner. The curcumin–Cu(II complex system with a 2:1 ratio exhibited the most significant effect. Further mechanistic study demonstrated that curcumin–Cu(II or –Zn(II complexes systems inhibited cell apoptosis via downregulating the nuclear factor κB (NF-κB pathway and upregulating Bcl-2/Bax pathway. In summary, the present study found that curcumin–Cu(II or –Zn(II complexes systems, especially the former, possess significant neuroprotective effects, which indicates the potential advantage of curcumin as a promising agent against AD and deserves further study.

  19. Calcium EXAFS establishes the Mn-Ca cluster in the oxygen-evolving complex of Photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Cinco, Roehl M.; McFarlane Holman, Karen L.; Robblee, John H.; Yano, Junko; Pizarro, Shelly A.; Bellacchio, Emanuele; Sauer, Kenneth; Yachandra, Vittal K.

    2002-08-02

    The proximity of Ca to the Mn cluster of the photosynthetic water-oxidation complex is demonstrated by X-ray absorption spectroscopy. We have collected EXAFS data at the Ca K-edge using active PS II membrane samples that contain approximately 2 Ca per 4 Mn. These samples are much less perturbed than previously investigated Sr-substituted samples, which were prepared subsequent to Ca depletion. The new Ca EXAFS clearly shows backscattering from Mn at 3.4 angstroms, a distance that agrees with that surmised from previously recorded Mn EXAFS. This result is also consistent with earlier related experiments at the Sr K-edge, using samples that contained functional Sr, that show Mn is {approx}; 3.5 angstroms distant from Sr. The totality of the evidence clearly advances the notion that the catalytic center of oxygen evolution is a Mn-Ca heteronuclear cluster.

  20. Anticancer Organometallic Osmium(II)-p-cymene Complexes.

    Science.gov (United States)

    Păunescu, Emilia; Nowak-Sliwinska, Patrycja; Clavel, Catherine M; Scopelliti, Rosario; Griffioen, Arjan W; Dyson, Paul J

    2015-09-01

    Osmium compounds are attracting increasing attention as potential anticancer drugs. In this context, a series of bifunctional organometallic osmium(II)-p-cymene complexes functionalized with alkyl or perfluoroalkyl groups were prepared and screened for their antiproliferative activity. Three compounds from the series display selectivity toward cancer cells, with moderate cytotoxicity observed against human ovarian carcinoma (A2780) cells, whereas no cytotoxicity was observed on non-cancerous human embryonic kidney (HEK-293) cells and human endothelial (ECRF24) cells. Two of these three cancer-cell-selective compounds induce cell death largely via apoptosis and were also found to disrupt vascularization in the chicken embryo chorioallantoic membrane (CAM) model. Based on these promising properties, these compounds have potential clinical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Stability of different zinc(II)-diamine complexes in aqueous solution with respect to structure and dynamics: a QM/MM MD study.

    Science.gov (United States)

    Fatmi, M Qaiser; Hofer, Thomas S; Randolf, Bernhard R; Rode, Bernd M

    2007-01-11

    In the context of our detailed study of the chemical behavior of aquo- and ammine-Zn(II) complexes, ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations were performed at the Hartree-Fock (HF) level for the zinc(II)-diamine complexes in aqueous solution. The initial structures of cis and trans isomers of the tetraaquodiamminezinc(II) complex were found to transform into the triaquodiamminezinc(II) complex by releasing one water ligand after approximately 6 and approximately 22 ps of simulation time, respectively. The structural and dynamical properties of these three zinc complexes, i.e., cis-[Zn(NH3)2(H2O)4]2+, trans-[Zn(NH3)2(H2O)4]2+, and [Zn(NH3)2(H2O)3]2+, were analyzed in terms of radial distribution functions (RDF), coordination number distributions (CND), angular distribution functions (ADF), tilt and theta angle distributions, ligands' mean residence times (MRTs), and ion-ligand stretching frequencies. One considerably elongated Zn-O bond of 2.43 A was observed in the case of the cis isomer for one of the water ligands located in the trans position to an ammonia ligand. In the trans isomer the average Zn-O bond length was observed to be 2.23 A, while in the triaquodiamminezinc(II) complex two distinct Zn-O bonds, namely 2.12 A for the ligands in the trigonal plane and 2.26 A for axial water molecules, were observed. As both of the octahedral isomers are transformed into the pentacoordinated structure within the picosecond range, they might be regarded as "metastable species or intermediates", while the triaquodiamminezinc(II) complex is the most stable species of the zinc(II)-diamine complex in aqueous solution.

  2. Spectroscopic, thermal and antibacterial studies on Mn(II and Co(II complexes derived from thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    SULEKH CHANDRA

    2009-08-01

    Full Text Available Mn(II and Co(II complexes having the general composition [M(L2X2] (where L = 2-pyridinecarboxaldehyde thiosemicarbazone, M = Mn(II and Co(II, X = Cl- and NO3- were synthesized. All the metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, EPR, electronic spectral studies and thermogravimetric analysis (TG. Based on the spectral studies, an octahedral geometry was assigned for all the complexes. Thermal studies of the compounds suggest that the complexes are more stable than the free ligand. This fact was supported by the kinetic parameters calculated using the Horowitz–Metzger (H–M and Coats–Redfern (C–R equations. The antibacterial properties of the ligand and its metal complexes were also examined and it was observed that the complexes are more potent bactericides than the free ligand.

  3. Cu(II AND Zn(II COMPLEX COMPOUNDS WITH BIGUANIDES AROMATIC DERIVATIVES. SYNTHESIS, CHARACTERIZATION, BIOLOGICAL ACTIVITY

    Directory of Open Access Journals (Sweden)

    Ticuţa Negreanu-Pîrjol

    2011-05-01

    Full Text Available In this paper we report the synthesis, physical-chemical characterization and antimicrobial activity of some new complex compounds of hetero-aromatic biguanides ligands, chlorhexidine base (CHX and chlorhexidine diacetate (CHXac2 with metallic ions Cu(II and Zn(II, in different molar ratio. The synthesized complexes were characterized by elemental chemical analysis and differential thermal analysis. The stereochemistry of the metallic ions was determined by infrared spectra, UV-Vis, EPR spectroscopy and magnetic susceptibility in the aim to establish the complexes structures. The biological activity of the new complex compounds was identified in solid technique by measuring minimum inhibition diameter of bacterial and fungal culture, against three standard pathogen strains, Escherichia coli ATCC 25922, Staphilococcus aureus ATCC 25923 and Candida albicans ATCC 10231. The results show an increased specific antimicrobial activity for the complexes chlorhexidine:Cu(II 1:1 and 1:2 compared with the one of the Zn(II complexes.

  4. Copper(II) and nickel(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone: Synthesis, characterization and biological activity

    Science.gov (United States)

    Prathima, B.; Subba Rao, Y.; Adinarayana Reddy, S.; Reddy, Y. P.; Varada Reddy, A.

    2010-09-01

    Benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone ligand (L) has been synthesized from benzyloxybenzaldehyde and 4-phenyl-3-thiosemicarbazide. Complexes of this ligand with chlorides of Cu(II) and Ni(II) have been prepared. The structure of the ligand (L) is proposed based on elemental analysis, IR and 1H NMR spectra. Its complexes with Cu(II) and Ni(II) ions are characterized from the studies of electronic as well as EPR spectra. On the basis of electronic and EPR studies, rhombically distorted octahedral structure has been proposed for Cu(II) complex while the Ni(II) complex has been found to acquire an octahedral structure. The ligand and their metal complexes have been tested in vitro for their biological effects. Their antibacterial activities against Gram-negative bacteria ( Escherichia coli and Klebsiella pneumoniae) and Gram-positive bacteria ( Staphylococcus aureus and Bacillus subtilis) have been investigated. The prepared metal complexes exhibit higher antibacterial activities than the parent ligand. The in vitro antioxidant activity of free ligand and its metal(II) complexes have also been investigated and the results however reveal that the ligand exhibits greater antioxidant activity than its complexes.

  5. DNA binding and biological activity of mixed ligand complexes of Cu(II, Ni(II and Co(II with quinolones and N donor ligand

    Directory of Open Access Journals (Sweden)

    S.M M Akram

    2015-10-01

    Full Text Available  AbstractMixed ligand complexes of  Cu(II, Ni(II and Co(II have been synthesized by using levofloxacin and bipyridyl and characterized using spectral and analytical techniques. The binding behavior of the Ni(II and Cu(II complexes with herring sperm DNA(Hs-DNA were determined using electronic absorption titration, viscometric measurements and cyclic voltammetry measurements. The binding constant calculated  for Cu(II and Ni(II complexes are 2.0 x 104 and 4.0 x 104 M-1 respectively. Detailed analysis reveals that these metal complexes interact with DNA through intercalative binding mode. The nuclease activity of  Cu(II and Ni(II complexes with ct-DNA was carried out using agarose gel electrophoresis technique. The antioxidant activities for the synthesized complexes have been tested and the antibacterial activity for Ni(II complex was also checked.Key words: Intercalation, hypochromism, red shift and  peak potential.

  6. Mixed ligand complexes of alkaline earth metals: Part XII. Mg(II, Ca(II, Sr(II and Ba(II complexes with 5-chlorosalicylaldehyde and salicylaldehyde or hydroxyaromatic ketones

    Directory of Open Access Journals (Sweden)

    MITHLESH AGRAWAL

    2002-04-01

    Full Text Available The reactions of alkaline earth metal chlorides with 5-chlorosalicylaldehyde and salicylaldehyde, 2-hydroxyacetophenone or 2-hydroxypropiophenone have been carried out in 1 : 1 : 1 mole ratio and the mixed ligand complexes of the type MLL’(H2O2 (where M = Mg(II, Ca(II, Sr(II and Ba(II, HL = 5-chlorosalicylaldehyde and HL’ = salicylaldehyde, 2-hydroxyacetophenone or 2-hydroxypropiophenone have been isolated. These complexes were characterized by TLC, conductance measurements, IR and 1H-NMR spectra.

  7. Synthesis and characterization of heterobimetallic complexes of the type [Cu(pn2][MCl4] where M = Co(II, Ni(II, Cu(II, Zn(II, Cd(II, and Hg(II

    Directory of Open Access Journals (Sweden)

    Seema Yadav

    2016-11-01

    Full Text Available A series of new bimetallic transition metal complexes of the type [Cu(pn2] [MCl4] have been synthesized (where M = Co(II, Ni(II, Cu(II, Zn(II, Cd(II and Hg(II, pn = 1,3-diaminopropane and characterized by elemental analysis, molar conductance, TGA, IR and electronic spectra. All the compounds are 1:1 electrolyte in DMF. The Cu(II ion is square-planar while metal ions in the anionic moiety acquire their usual tetrahedral arrangement. On the basis of these studies it is concluded that anionic moiety is electrically stabilized by its cationic counterpart.

  8. 454 sequencing reveals extreme complexity of the class II Major Histocompatibility Complex in the collared flycatcher

    Directory of Open Access Journals (Sweden)

    Gustafsson Lars

    2010-12-01

    Full Text Available Abstract Background Because of their functional significance, the Major Histocompatibility Complex (MHC class I and II genes have been the subject of continuous interest in the fields of ecology, evolution and conservation. In some vertebrate groups MHC consists of multiple loci with similar alleles; therefore, the multiple loci must be genotyped simultaneously. In such complex systems, understanding of the evolutionary patterns and their causes has been limited due to challenges posed by genotyping. Results Here we used 454 amplicon sequencing to characterize MHC class IIB exon 2 variation in the collared flycatcher, an important organism in evolutionary and immuno-ecological studies. On the basis of over 152,000 sequencing reads we identified 194 putative alleles in 237 individuals. We found an extreme complexity of the MHC class IIB in the collared flycatchers, with our estimates pointing to the presence of at least nine expressed loci and a large, though difficult to estimate precisely, number of pseudogene loci. Many similar alleles occurred in the pseudogenes indicating either a series of recent duplications or extensive concerted evolution. The expressed alleles showed unambiguous signals of historical selection and the occurrence of apparent interlocus exchange of alleles. Placing the collared flycatcher's MHC sequences in the context of passerine diversity revealed transspecific MHC class II evolution within the Muscicapidae family. Conclusions 454 amplicon sequencing is an effective tool for advancing our understanding of the MHC class II structure and evolutionary patterns in Passeriformes. We found a highly dynamic pattern of evolution of MHC class IIB genes with strong signals of selection and pronounced sequence divergence in expressed genes, in contrast to the apparent sequence homogenization in pseudogenes. We show that next generation sequencing offers a universal, affordable method for the characterization and, in perspective

  9. and Ni (II) complexes with Schiff base derived from 2-amino benzoic

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: The complexes of Mn (II) and Ni (II) with Schiff base derived from salicylaldehyde and 2-amino benzoic acid have been prepared and characterized by gravimetry, potentiometry, molar conductance and infrared analyses. The solubility test on the Schiff base and its nickel(II) complex revealed their solubility in ...

  10. ynthesis, theoretical study on Zinc (II and Ni(II complexes of 5-methoxyisatin 3-[N-(4-chlorophenyl thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    Fatma Kandemirli

    2012-03-01

    Full Text Available Zinc(II and nickel(II-complexes of 5-methoxyisatin 3-[N-(4-chlorophenyl thiosemicarbazone] (H2MICP were synthesized and characterized by infrared, ultraviolet and 1H-NMR spectroscopies as well as elemental analysis. Model of H2MICP and its zinc(II and nickel(II-complexes were optimized with B3LYP method using 6-31G(d,p, 6-311G(d,p, 6-311++G(d,p, 6-311++G(2d,2p basis sets. The calculated 1H-NMR, UV and IR spectra data were compared with experimental results. In addition to the Natural Bond Orbital (NBO analysis of H2MICP and its Zinc(II and Nickel(II complexes, Fukui functions of H2MICP were also reported.

  11. Synthesis and characterization of thermally stable oligomer-metal complexes of copper(II, nickel(II, zinc(II and cobalt(II derived from oligo-p-nitrophenylazomethinephenol

    Directory of Open Access Journals (Sweden)

    Ufuk S. Vural

    2006-12-01

    Full Text Available Thermally stable metal complexes based on oligomers were prepared by the reaction between oligo-p-nitrophenilazomethinephenol (ONPAP and Cu(II, Ni(II, Zn(II and Co(II ions. The properties of oligomer-metal complexes were studied by elemental, FT-IR and magnetic moments analyses. The thermal stabilities of the oligomer-metal complexes were compared by thermogravimetric (TG and differential thermal (DTA analyses. According to TG, oligomer-metal complexes were stable against to temperature and thermooxidative decomposition. The weight losses of oligomer-metal complexes were found to be 5 and 50 % at 200 and > 850 (Cu(II, 172 and 600 (Ni(II, 252 and > 850 (Zn(II and 174 and 510 (Co(II, oC, respectively. Based on half degradation temperature parameters Cu(II and Zn(II complexes were more resistant than the others.

  12. Synthesis, physico-chemical studies of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes with some p-substituted acetophenone benzoylhydrazones and their antimicrobial activity.

    Science.gov (United States)

    Singh, Vinod P; Singh, Shweta; Katiyar, Anshu

    2009-04-01

    Complexes of the type [M(pabh)(H2O)Cl], [M(pcbh)(H2O)Cl] and [M(Hpabh)(H2O)2 (SO4)] where, M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpabh = p-amino acetophenone benzoyl hydrazone and Hpcbh = p-chloro acetophenone benzoyl hydrazone have been synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic susceptibility measurements, electronic, ESR and IR spectra, thermal (TGA & DTA) and X-ray diffraction studies. Co(II), Ni(II) and Cu(II) chloride complexes are square planar, whereas their sulfate complexes have spin-free octahedral geometry. ESR spectra of Cu(II) complexes with Hpabh are axial and suggest d(x(2)-y(2) as the ground state. The ligand is bidentate bonding through > C = N--and deprotonated enolate group in all the chloro complexes, whereas, >C = N and >C = O groups in all the sulfato complexes. Thermal studies (TGA & DTA) on [Cu(Hpabh)(H2O)2(SO4)] indicate a multistep decomposition pattern, which are both exothermic and endothermic in nature. X-ray powder diffraction parameters for [Co(pabh)(H2O)Cl] and [Ni(Hpabh)(H2O)2(SO4)] correspond to tetragonal and orthorhombic crystal lattices, respectively. The ligands as well as their complexes show a significant antifungal and antibacterial activity. The metal complexes are more active than the ligand.

  13. Last PS magnet refurbished

    CERN Document Server

    2009-01-01

    PS Magnet Refurbishment Programme Completed. The 51st and final refurbished magnet was transported to the PS on Tuesday 3 February. The repair and consolidation work on the PS started back in 2003 when two magnets and a busbar connection were found to be faulty during routine high-voltage tests. The cause of the fault was a combination of age and radiation on electrical insulation. After further investigation the decision was taken to overhaul half of the PS’s 100 magnets to reduce the risk of a similar fault. As from 20 February the PS ring will start a five-week test programme to be ready for operation at the end of March.

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

    Science.gov (United States)

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

    2015-03-01

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

  15. Characterization and biological studies on Co(II), Ni(II) and Cu(II) complexes of carbohydrazones ending by pyridyl ring

    Science.gov (United States)

    Abu El-Reash, G. M.; El-Gammal, O. A.; Ghazy, S. E.; Radwan, A. H.

    2013-03-01

    The chelating behavior of ligands based on carbohydrazone core modified with pyridine end towards Co(II), Ni(II) and Cu(II) ions have been examined. The ligands derived from the condensation of carbohydrazide with 2-acetylpyridine (H2APC) and 4-acetylpyridine (H2APEC). The 1H NMR, IR data and the binding energy calculations of H2APC revealed the presence of two stereoisomers syn and anti in the solid state and in the solution. The 1H NMR, IR data and the binding energy calculations confirmed the presence of H2APEC in one keto form only in the solid state and in the solution. The spectroscopic data confirmed that H2APC behaves as a monobasic pentadentate in Co(II) and Cu(II) complexes and as mononegative tetradentate in Ni(II) complex. On the other hand, H2APEC acts as a mononegative tridentate in Co(II) complex, neutral tridentate in Ni(II) complex and neutral bidentate in Cu(II) complex. The electronic spectra and the magnetic measurements of complexes as well as the ESR of the copper complexes suggested the octahedral geometry. The bond length and bond angles were evaluated by DFT method using material studio program. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The antioxidant (DDPH and ABTS methods), anti-hemolytic and in vitro Ehrlich ascites of the compounds have been screened.

  16. Bipyrimidine ruthenium(II) arene complexes: structure, reactivity and cytotoxicity.

    Science.gov (United States)

    Betanzos-Lara, Soledad; Novakova, Olga; Deeth, Robert J; Pizarro, Ana M; Clarkson, Guy J; Liskova, Barbora; Brabec, Viktor; Sadler, Peter J; Habtemariam, Abraha

    2012-10-01

    The synthesis and characterization of complexes [(η(6)-arene)Ru(N,N')X][PF(6)], where arene is para-cymene (p-cym), biphenyl (bip), ethyl benzoate (etb), hexamethylbenzene (hmb), indane (ind) or 1,2,3,4-tetrahydronaphthalene (thn), N,N' is 2,2'-bipyrimidine (bpm) and X is Cl, Br or I, are reported, including the X-ray crystal structures of [(η(6)-p-cym)Ru(bpm)I][PF(6)], [(η(6)-bip)Ru(bpm)Cl][PF(6)], [(η(6)-bip)Ru(bpm)I][PF(6)] and [(η(6)-etb)Ru(bpm)Cl][PF(6)]. Complexes in which N,N' is 1,10-phenanthroline (phen), 1,10-phenanthroline-5,6-dione or 4,7-diphenyl-1,10-phenanthroline (bathophen) were studied for comparison. The Ru(II) arene complexes undergo ligand-exchange reactions in aqueous solution at 310 K; their half-lives for hydrolysis range from 14 to 715 min. Density functional theory calculations on [(η(6)-p-cym)Ru(bpm)Cl][PF(6)], [(η(6)-p-cym)Ru(bpm)Br][PF(6)], [(η(6)-p-cym)Ru(bpm)I][PF(6)], [(η(6)-bip)Ru(bpm)Cl][PF(6)], [(η(6)-bip)Ru(bpm)Br][PF(6)] and [(η(6)-bip)Ru(bpm)I][PF(6)] suggest that aquation occurs via an associative pathway and that the reaction is thermodynamically favourable when the leaving ligand is I > Br ≈ Cl. pK (a)* values for the aqua adducts of the complexes range from 6.9 to 7.32. A binding preference for 9-ethylguanine (9-EtG) compared with 9-ethyladenine (9-EtA) was observed for [(η(6)-p-cym)Ru(bpm)Cl][PF(6)], [(η(6)-hmb)Ru(bpm)Cl](+), [(η(6)-ind)Ru(bpm)Cl](+), [(η(6)-thn)Ru(bpm)Cl](+), [(η(6)-p-cym)Ru(phen)Cl](+) and [(η(6)-p-cym)Ru(bathophen)Cl](+) in aqueous solution at 310 K. The X-ray crystal structure of the guanine complex [(η(6)-p-cym)Ru(bpm)(9-EtG-N7)][PF(6)](2) shows multiple hydrogen bonding. Density functional theory calculations show that the 9-EtG adducts of all complexes are thermodynamically preferred compared with those of 9-EtA. However, the bmp complexes are inactive towards A2780 human ovarian cancer cells. Calf thymus DNA interactions for [(η(6)-p-cym)Ru(bpm)Cl][PF(6)] and [(η(6)-p

  17. Spectroscopic, DNA binding ability, biological activity, DFT calculations and non linear optical properties (NLO) of novel Co(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes with ONS Schiff base

    Science.gov (United States)

    Abdel Aziz, Ayman A.; Elantabli, Fatma M.; Moustafa, H.; El-Medani, Samir M.

    2017-08-01

    The reaction of Co(II), Cu(II), Zn(II), Cd(II) and Hg(II) with the synthesized N-(2-hydroxy-1-naphthylidene)-2-aminothiophenol Schiff base ligand (H2L) at room temperature resulted in the formation of the five complexes; [Co(HL)2]H2O, 1; [M(HL)2] (M = Cu, Zn and Cd), (2-4) and [Hg(HL)Cl], 5. The ligand and its complexes were characterized based on elemental analyses, IR, 1H NMR, magnetic measurement, molar conductance, and thermal analysis. Coats and Redfern method was used to compute the kinetic and thermodynamic parameters. Antimicrobial activities of H2L and its complexes have been studied. The binding of Co(II), Cu(II) and Zn(II) complexes to calf thymus DNA (CT-DNA) has been investigated using UV-Vis and fluorescence absorption spectra. The results indicated that the ligand and its complexes may bind to DNA by intercalation modes, with a much higher binding affinity of the complexes than that of the ligand. The equilibrium geometries of the studied complexes are investigated theoretically at the B3LYP/LANL2DZ level of theory, and it was found that these geometries are non-linear. The calculated EHOMO and ELUMO energies of the studied complexes can be used to calculate the global properties. The calculated nonlinear optical parameters (NLO); first order hyperpolarizibility (β) of the studied complexes show promising optical properties.

  18. Five coordinate M(II)-diphenolate [M = Zn(II), Ni(II), and Cu(II)] Schiff base complexes exhibiting metal- and ligand-based redox chemistry.

    Science.gov (United States)

    Franks, Mark; Gadzhieva, Anastasia; Ghandhi, Laura; Murrell, David; Blake, Alexander J; Davies, E Stephen; Lewis, William; Moro, Fabrizio; McMaster, Jonathan; Schröder, Martin

    2013-01-18

    Five-coordinate Zn(II), Ni(II), and Cu(II) complexes containing pentadentate N(3)O(2) Schiff base ligands [1A](2-) and [1B](2-) have been synthesized and characterized. X-ray crystallographic studies reveal five coordinate structures in which each metal ion is bound by two imine N-donors, two phenolate O-donors, and a single amine N-donor. Electron paramagnetic resonance (EPR) spectroscopic studies suggest that the N(3)O(2) coordination spheres of [Cu(1A)] and [Cu(1B)] are retained in CH(2)Cl(2) solution and solid-state superconducting quantum interference device (SQUID) magnetometric studies confirm that [Ni(1A)] and [Ni(1B)] adopt high spin (S = 1) configurations. Each complex exhibits two reversible oxidation processes between +0.05 and +0.64 V vs [Fc](+)/[Fc]. The products of one- and two-electron oxidations have been studied by UV/vis spectroelectrochemistry and by EPR spectroscopy which confirm that each oxidation process for the Zn(II) and Cu(II) complexes is ligand-based with sequential formation of mono- and bis-phenoxyl radical species. In contrast, the one-electron oxidation of the Ni(II) complexes generates Ni(III) products. This assignment is supported by spectroelectrochemical and EPR spectroscopic studies, density functional theory (DFT) calculations, and the single crystal X-ray structure of [Ni(1A)][BF(4)] which contains Ni in a five-coordinate distorted trigonal bipyramidal geometry.

  19. Synthesis and characterization of thermally stable oligomer-metal complexes of copper(II), nickel(II), zinc(II) and cobalt(II) derived from oligo-p-nitrophenylazomethinephenol

    OpenAIRE

    Ufuk S. Vural; Hasan Mart; H. Okkes Demir; Ozlem Sarıöz; Vefa Muradoğlu; M. Cihangir Koç

    2006-01-01

    Thermally stable metal complexes based on oligomers were prepared by the reaction between oligo-p-nitrophenilazomethinephenol (ONPAP) and Cu(II), Ni(II), Zn(II) and Co(II) ions. The properties of oligomer-metal complexes were studied by elemental, FT-IR and magnetic moments analyses. The thermal stabilities of the oligomer-metal complexes were compared by thermogravimetric (TG) and differential thermal (DTA) analyses. According to TG, oligomer-metal complexes were stable against to temperatur...

  20. Design, synthesis, spectral characterization, DNA interaction and biological activity studies of copper(II), cobalt(II) and nickel(II) complexes of 6-amino benzothiazole derivatives

    Science.gov (United States)

    Daravath, Sreenu; Kumar, Marri Pradeep; Rambabu, Aveli; Vamsikrishna, Narendrula; Ganji, Nirmala; Shivaraj

    2017-09-01

    Two novel Schiff bases, L1 = (2-benzo[d]thiazol-6-ylimino)methyl)-4,6-dichlorophenol), L2 = (1-benzo[d]thiazol-6-ylimino)methyl)-6-bromo-4-chlorophenol) and their bivalent transition metal complexes [M(L1)2] and [M(L2)2], where M = Cu(II), Co(II) and Ni(II) were synthesized and characterized by elemental analysis, NMR, IR, UV-visible, mass, magnetic moments, ESR, TGA, SEM, EDX and powder XRD. Based on the experimental data a square planar geometry around the metal ion is assigned to all the complexes (1a-2c). The interaction of synthesized metal complexes with calf thymus DNA was explored using UV-visible absorption spectra, fluorescence and viscosity measurements. The experimental evidence indicated that all the metal complexes strongly bound to CT-DNA through an intercalation mode. DNA cleavage experiments of metal(II) complexes with supercoiled pBR322 DNA have also been explored by gel electrophoresis in the presence of H2O2 as well as UV light, and it is found that the Cu(II) complexes cleaved DNA more effectively compared to Co(II), Ni(II) complexes. In addition, the ligands and their metal complexes were screened for antimicrobial activity and it is found that all the metal complexes were more potent than free ligands.

  1. Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II, Co(II, Ni(II, Cu(II, and Zn(II] metals

    Directory of Open Access Journals (Sweden)

    Nahid Nishat

    2016-09-01

    Full Text Available A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II, Co(II, Ni(II, Cu(II and Zn(II. All the polymeric compounds were characterized by (FT-IR spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA and antibacterial activities. Polymer complexes of Mn(II, Co(II and Ni(II show octahedral geometry, while polymer complexes of Cu(II and Zn(II show square planar and tetrahedral geometry, respectively. The TGA revealed that all the polymer metal complexes are more thermally stable than their parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM-D-5338-93 standards of biodegradable polymers by CO2 evolution method which says that coordination decreases biodegradability. The antibacterial activity was screened with the agar well diffusion method against some selected microorganisms. Among all the complexes, the antibacterial activity of the Cu(II polymer–metal complex showed the highest zone of inhibition because of its higher stability constant.

  2. Synthesis, characterization and biological activities of Cu(II), Co(II), Mn(II), Fe(II), and UO2(VI) complexes with a new Schiff Base hydrazone: O-hydroxyacetophenone-7-chloro-4-quinoline hydrazone

    National Research Council Canada - National Science Library

    Al-Shaalan, Nora H

    2011-01-01

    .... This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II), Ni(II), Co(II), Mn(II), UO(2) (VI) and Fe(II) to form either mono- or binuclear complexes...

  3. Development and molecular modeling of Co(II, Ni(II and Cu(II complexes as high acting anti breast cancer agents

    Directory of Open Access Journals (Sweden)

    S.A. Deodware

    2017-02-01

    Full Text Available A series of cobalt, nickel and copper complexes of bidentate Schiff base derived from the condensation reaction of 4-amino-5-mercapto-3-methyl-1,2,4-triazole with 2-nitrobenzaldehyde had been synthesized. The synthesized Schiff base and their metal complexes have been characterized with the support of more than a few physicochemical techniques, elemental evaluation, magnetic moment measurements, spectroscopic, thermo gravimetric techniques and X-ray powder diffraction. Spectral analysis exhibits square planer geometry for Cu(II complex while octahedral geometry for Co(II and Ni(II complexes. The Schiff base and their complexes have been screened for their anticancer activity using MCF7 cell line. In molecular docking learn exhibits that Ni(II complex is more active confirmed quantity of interaction in particular hydrogen bond interaction with ASN142 and charge interactions with ASP97 and GLU99.

  4. Metalloantibiotics: synthesis, characterization and in-vitro antibacterial studies on cobalt (II), copper (II), nickel (II) and zinc (II) complexes with cloxacillin.

    Science.gov (United States)

    Chohan, Zahid H; Supuran, Claudiu T

    2006-08-01

    The synthesis and characterization of cloxacillin (clox) complexes with divalent metal ions [Co (II), Cu (II), Ni (II) and Zn (II)] is described. The nature of bonding of the chelated cloxacillin and the structures of the metal complexes have been elucidated on the basis of their physical and spectroscopic data. In all the complexes, the cloxacillin acts as a uninegatively charged bidentate ligand with coordination involving the carboxylate-O and endocyclic-N of the beta-lactam ring. The new compounds have been screened for in-vitro antibacterial activity against Escherichia coli (a), Klebsiella pneumonae (b), Proteus mirabilis (c), Pseudomonas aeruginosa (d), Salmonella typhi (e), Shigella dysentriae (f), Bacillus cereus (g), Corynebacterium diphtheriae (h), Staphylococcus aureus (j) and Streptococcus pyogenes (k) bacterial strains. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties. All compounds, respectively, showed a promising activity (90%) against five bacterial species at 10 microg/ml concentration and a significant activity (52%) against the same test bacteria at 25 microg/ml concentration.

  5. Ultrafast energy transfer within the photosystem II core complex.

    Science.gov (United States)

    Pan, Jie; Gelzinis, Andrius; Chorošajev, Vladimir; Vengris, Mikas; Senlik, S Seckin; Shen, Jian-Ren; Valkunas, Leonas; Abramavicius, Darius; Ogilvie, Jennifer P

    2017-06-14

    We report 2D electronic spectroscopy on the photosystem II core complex (PSII CC) at 77 K under different polarization conditions. A global analysis of the high time-resolution 2D data shows rapid, sub-100 fs energy transfer within the PSII CC. It also reveals the 2D spectral signatures of slower energy equilibration processes occurring on several to hundreds of picosecond time scales that are consistent with previous work. Using a recent structure-based model of the PSII CC [Y. Shibata, S. Nishi, K. Kawakami, J. R. Shen and T. Renger, J. Am. Chem. Soc., 2013, 135, 6903], we simulate the energy transfer in the PSII CC by calculating auxiliary time-resolved fluorescence spectra. We obtain the observed sub-100 fs evolution, even though the calculated electronic energy shows almost no dynamics at early times. On the other hand, the electronic-vibrational interaction energy increases considerably over the same time period. We conclude that interactions with vibrational degrees of freedom not only induce population transfer between the excitonic states in the PSII CC, but also reshape the energy landscape of the system. We suggest that the experimentally observed ultrafast energy transfer is a signature of excitonic-polaron formation.

  6. Carbonylation of Ethene Catalysed by Pd(II-Phosphine Complexes

    Directory of Open Access Journals (Sweden)

    Gianni Cavinato

    2014-09-01

    Full Text Available This review deals with olefin carbonylation catalysed by Pd(II-phosphine complexes in protic solvents. In particular, the results obtained in the carbonylation with ethene are reviewed. After a short description of the basic concepts relevant to this catalysis, the review treats in greater details the influence of the bite angle, skeletal rigidity, electronic and steric bulk properties of the ligand on the formation of the products, which range from high molecular weight perfectly alternating polyketones to methyl propanoate. It is shown that the steric bulk plays a major role in directing the selectivity. Particular emphasis is given to the factors governing the very active and selective catalysis to methyl propanoate, including the mechanism of the catalytic cycles with diphosphine- and monophosphine-catalysts. A brief note on the synthesis of methyl propanoate using a “Lucite” type catalyst in ionic liquids is also illustrated. A chapter is dedicated to the carbonylation of olefins in aqueous reaction media. The nonalternating CO-ethene copolymerization is also treated.

  7. Hippocampal Lipid Homeostasis in APP/PS1 Mice is Modulated by a Complex Interplay Between Dietary DHA and Estrogens: Relevance for Alzheimer's Disease.

    Science.gov (United States)

    Díaz, Mario; Fabelo, Noemí; Casañas-Sánchez, Verónica; Marin, Raquel; Gómez, Tomás; Quinto-Alemany, David; Pérez, José A

    2016-01-01

    Current evidence suggests that lipid homeostasis in the hippocampus is affected by different genetic, dietary, and hormonal factors, and that its deregulation may be associated with the onset and progression of Alzheimer's disease (AD). However, the precise levels of influence of each of these factors and their potential interactions remain largely unknown, particularly during neurodegenerative processes. In the present study, we have performed multifactorial analyses of the combined effects of diets containing different doses of docosahexaenoic acid (DHA), estrogen status (ovariectomized animals receiving vehicle or 17β-estradiol), and genotype (wild-type or transgenic APP/PS1 mice) in hippocampal lipid profiles. We have observed that the three factors affect lipid classes and fatty acid composition to different extents, and that strong interactions between these factors exist. The most aberrant lipid profiles were observed in APP/PS1 animals receiving DHA-poor diets and deprived of estrogens. Conversely, wild-type animals under a high-DHA diet and receiving estradiol exhibited a lipid profile that closely resembled that of the hippocampus of control animals. Interestingly, though the lipid signatures of APP/PS1 hippocampi markedly differed from wild-type, administration of a high-DHA diet in the presence of estrogens gave rise to a lipid profile that approached that of control animals. Paralleling changes in lipid composition, patterns of gene expression of enzymes involved in lipid biosynthesis were also altered and affected by combination of experimental factors. Overall, these results indicate that hippocampal lipid homeostasis is strongly affected by hormonal and dietary conditions, and that manipulation of these factors might be incorporated in AD therapeutics.

  8. Spectral, thermal and magnetic properties of Cu(II and Ni(II complexes with Schiff base ligands

    Directory of Open Access Journals (Sweden)

    Cristóvão Beata

    2011-01-01

    Full Text Available Mononuclear copper(II and nickel(II complexes of the formulae [Cu(L1] (1, [Ni(L1] (2, [Cu(L2] (3 and [Cu(L3H2O] (4 (where L1 = N,N’-ethylenebis(4,6-dimethoxysalicylidenaminato, L2 = N,N’-ethylenebis(5-bromosalicylidenaminato and L3 = N,N’-ethylenebis(5-bromo-3-methoxysalicylidenaminato were synthesized as microcrystalline powders and characterized by IR spectroscopy, thermal analysis and magnetic measurements. The magnetic susceptibility of the Cu(II complexes changed with temperature according to the Curie-Weiss law. The complexes 1, 3 and 4 exhibit magnetic moments of 2.29, 2.20 and 1.88 µB, respectively, at 303 K. These values practically do not change with lowering the temperature to 77 K. The nickel(II complex 2 is diamagnetic.

  9. Novel (cyanamide)Zn(II) complexes and zinc(ii)-mediated hydration of the cyanamide ligands.

    Science.gov (United States)

    Smirnov, Andrey S; Butukhanova, Ekaterina S; Bokach, Nadezhda A; Starova, Galina L; Gurzhiy, Vladislav V; Kuznetsov, Maxim L; Kukushkin, Vadim Yu

    2014-11-14

    The cyanamides NCNR2 (R2 = Me2, Ph2, C5H10) react with ZnX2 (X = Cl, Br, I) in a 2 : 1 molar ratio at RT, giving a family of zinc(ii) complexes [ZnX2(NCNR2)2] (R2 = Me2, X = Cl , X = Br , X = I ; R2 = C5H10, X = Cl , X = Br ; X = I ; R2 = Ph2, X = Cl , X = Br , X = I ; 75-92% yields). Complexes and undergo ligand redistribution in wet CH2Cl2 solutions giving the [Zn(NCNPh2)4(H2O)2][Zn2(μ-X)2X4] (X = Cl , Br ) species that were characterized by (1)H NMR, HRESI-MS, and X-ray diffraction. Halide abstraction from by the action of AgCF3SO3 or treatment of Zn(CF3SO3)2 with NCNR2 (R2 = Me2, C5H10) leads to labile complexes [Zn(CF3SO3)2(NCNR2)3] (R2 = Me2, ; C5H10, ). Crystallization of from wet CH2Cl2 or from the reaction mixture gave [Zn(NCNMe2)3(H2O)2](SO3CF3)2 () or [Zn(CF3SO3)2(NCNMe2)2]∞ (), whose structures were determined by X-ray diffraction. The Zn(II)-mediated hydration was observed for the systems comprising ZnX2 (X = Cl, Br, I), 2 equiv. NCNR2 (R2 = Me2, C5H10, Ph2) and ca. 40-fold excess of water and conducted in acetone at 60 °C (R2 = Me2, C5H10) or 80 °C (R2 = Ph2) in closed vials, and it gives the urea complexes [ZnX2{OC(NR2)NH2}] (R2 = Me2, X = Cl , X = Br , X = I ; R = C5H10, X = Cl , X = Br ; X = I ; R2 = Ph2, X = Cl , X = Br , X = I ; 57-81%). In contrast to the Zn(II)-mediated hydration of conventional nitriles, which proceeds only in the presence of co-catalyzing oximes or carboxamides, the reaction with cyanamides does not require any co-catalyst. Complexes , were characterized by (1)H, (13)C{(1)H} NMR, IR, HRESI-MS, and X-ray crystallography (for , , , , and ), whereas and were characterized by HRESI(+)-MS and (1)H and (13)C{(1)H} NMR (for ). The structural features of the cyanamide complexes , , , and were interpreted by theoretical calculations at the DFT level.

  10. Mononuclear nickel (II) and copper (II) coordination complexes supported by bispicen ligand derivatives: Experimental and computational studies

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Nirupama; Niklas, Jens; Poluektov, Oleg; Van Heuvelen, Katherine M.; Mukherjee, Anusree

    2017-01-01

    The synthesis, characterization and density functional theory calculations of mononuclear Ni and Cu complexes supported by the N,N’-Dimethyl-N,N’-bis-(pyridine-2-ylmethyl)-1,2-diaminoethane ligand and its derivatives are reported. The complexes were characterized by X-ray crystallography as well as by UV-visible absorption spectroscopy and EPR spectroscopy. The solid state structure of these coordination complexes revealed that the geometry of the complex depended on the identity of the metal center. Solution phase characterization data are in accord with the solid phase structure, indicating minimal structural changes in solution. Optical spectroscopy revealed that all of the complexes exhibit color owing to d-d transition bands in the visible region. Magnetic parameters obtained from EPR spectroscopy with other structural data suggest that the Ni(II) complexes are in pseudo-octahedral geometry and Cu(II) complexes are in a distorted square pyramidal geometry. In order to understand in detail how ligand sterics and electronics affect complex topology detailed computational studies were performed. The series of complexes reported in this article will add significant value in the field of coordination chemistry as Ni(II) and Cu(II) complexes supported by tetradentate pyridyl based ligands are rather scarce.

  11. CART treatment improves memory and synaptic structure in APP/PS1 mice.

    Science.gov (United States)

    Jin, Jia-li; Liou, Anthony K F; Shi, Yejie; Yin, Kai-lin; Chen, Ling; Li, Ling-ling; Zhu, Xiao-lei; Qian, Lai; Yang, Rong; Chen, Jun; Xu, Yun

    2015-05-11

    Major characteristics of Alzheimer's disease (AD) include deposits of β-amyloid (Aβ) peptide in the brain, loss of synapses, and cognitive dysfunction. Cocaine- and amphetamine-regulated transcript (CART) has recently been reported to attenuate Aβ-induced toxicity. In this study, CART localization in APP/PS1 mice was characterized and the protective effects of exogenous CART treatment were examined. Compared to age-matched wild type mice, 8-month-old APP/PS1 mice had significantly greater CART immunoreactivity in the hippocampus and cortex. A strikingly similar pattern of Aβ plaque-associated CART immunoreactivity was observed in the cortex of AD cases. Treatment of APP/PS1 mice with exogenous CART ameliorated memory deficits; this effect was associated with improvements in synaptic ultrastructure and long-term potentiation, but not a reduction of the Aβ plaques. Exogenous CART treatment in APP/PS1 mice prevented depolarization of the mitochondrial membrane and stimulated mitochondrial complex I and II activities, resulting in an increase in ATP levels. CART treatment of APP/PS1 mice also reduced reactive oxygen species and 4-hydroxynonenal, and mitigated oxidative DNA damage. In summary, CART treatment reduced multiple neuropathological measures and improved memory in APP/PS1 mice, and may therefore be a promising and novel therapy for AD.

  12. Synthesis and characterization of a tetraaza macrocyclic ligand and its cobalt(II, nickel(II and copper(II complexes

    Directory of Open Access Journals (Sweden)

    SULEKH CHANDR

    2010-07-01

    Full Text Available Co(II, Ni(II, and Cu(II complexes with a tetradentate nitrogen donor [N4] macrocyclic ligand, viz. 6,15-dimethyl-8,17diphenyl-7,16-dihydrodibenzo[b,i][1.4.8.11]tetraazacyclotetradecine, were synthesized. Their structures were determined based on elemental analyses, molar conductance and magnetic susceptibility measurements, and IR, 1H-NMR (ligand and electronic spectral studies. Based on analytical and molar conductance data, the complexes may be formulated as [M(LCl2] and [M’(L]Cl2 (where M = Co(II and Cu(II, and M’ = Ni(II due to their non-electrolytic and 1:2 electrolytic nature. Based on spectral studies, an octahedral geometry was assigned for the Co(II complex, whereas square-planar and tetragonal geometry were proposed for the Ni(II and Cu(II complexes, respectively. The synthesized ligand and its complexes were screened for fungicidal activity against two pathogenic fungi (i.e., Fusarium moniliformae and Rhizoctonia solani to assess their growth inhibiting potential.

  13. Physicochemical impact studies of gamma rays on "aspirin" analgesics drug and its metal complexes in solid form: Synthesis, spectroscopic and biological assessment of Ca(II), Mg(II), Sr(II) and Ba(II) aspirinate complexes

    Science.gov (United States)

    Refat, Moamen S.; Sharshar, T.; Elsabawy, Khaled M.; Heiba, Zein K.

    2013-09-01

    Metal aspirinate complexes, M2(Asp)4, where M is Mg(II), Ca(II), Sr(II) or Ba(II) are formed by refluxed of aspirin (Asp) with divalent non-transition metal ions of group (II) and characterized by elemental analysis and spectroscopic measurements (infrared, electronic, 1H NMR, Raman, X-ray powder diffraction and scanning electron microscopy). Elemental analysis of the chelates suggests the stoichiometry is 1:2 (metal:ligand). Infrared spectra of the complexes agree with the coordination to the central metal atom through three donation sites of two oxygen atoms of bridge bidentate carboxylate group and oxygen atom of sbnd Cdbnd O of acetyl group. Infrared spectra coupled with the results of elemental analyzes suggested a distorted octahedral structure for the M(II) aspirinate complexes. Gamma irradiation was tested as a method for stabilization of aspirin as well as their complexes. The effect of gamma irradiation, with dose of 80 Gy, on the properties of aspirinate complexes was studied. The aspirinate chelates have been screened for their in vitro antibacterial activity against four bacteria, gram-positive (Bacillus subtilis and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to possess more antibacterial activity than the free aspirin chelate.

  14. Spectroscopic characterization, antioxidant and antitumour studies of novel bromo substituted thiosemicarbazone and its copper(II), nickel(II) and palladium(II) complexes

    Science.gov (United States)

    Jagadeesh, M.; Lavanya, M.; Kalangi, Suresh K.; Sarala, Y.; Ramachandraiah, C.; Varada Reddy, A.

    2015-01-01

    A new, slightly distorted octahedral complex of copper(II), square planar complexes of nickel(II) and palladium(II) with 2,4‧-dibromoacetophenone thiosemicarbazone (DBAPTSC) are synthesized. The ligand and the complexes are characterized by FT-IR, FT-Raman, powder X-ray diffraction studies. The IR and Raman data are correlated for the presence of the functional groups which specifically helped in the confirmation of the compounds. In addition, the free ligand is unambiguously characterized by 1H and 13C NMR spectroscopy while the copper(II) complex is characterized by electron paramagnetic resonance spectroscopy (EPR). The g values for the same are found to be 2.246 (g1), 2.012 (g2) and 2.005 (g3) which suggested rhombic distortions. The HOMO-LUMO band gap calculations for these compounds are found to be in between 0.5 and 4.0 eV and these compounds are identified as semiconducting materials. The synthesized ligand and its copper(II), nickel(II) and palladium(II) complexes are subjected to antitumour activity against the HepG2 human hepatoblastoma cell lines. Among all the compounds, nickel(II) complex is found to exert better antitumour activity with 57.6% of cytotoxicity.

  15. 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.

  16. Synthesis, Spectral and Antimicrobial Studies of Some Co(II, Ni(II and Cu(II Complexes Containing 2-Thiophenecarboxaldehyde Moiety

    Directory of Open Access Journals (Sweden)

    A. P. Mishra

    2012-01-01

    Full Text Available Some new Schiff base metal complexes of Co(II, Ni(II and Cu(II derived from 3-chloro-4-fluoroaniline (HL1 and 4-fluoroaniline (HL2 with 2-thiophenecarboxaldehyde have been synthesized and characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR and magnetic susceptibility. The complexes exhibit coordination number 4 or 6. The complexes are colored and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand ratio. FAB-mass data show degradation pattern of the complexes. The Schiff base and metal complexes show a good activity against the bacteria; B. subtilis, E. coli and S. aureus and fungi A. niger, A. flavus and C. albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.

  17. Metal (II) Complexes Derived from Naphthofuran-2-carbohydrazide and Diacetylmonoxime Schiff Base: Synthesis, Spectroscopic, Electrochemical, and Biological Investigation

    Science.gov (United States)

    Sumathi, R. B.; Halli, M. B.

    2014-01-01

    A new Schiff base and a new series of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) complexes were synthesized by the condensation of naphthofuran-2-carbohydrazide and diacetylmonoxime. Metal complexes of the Schiff base were prepared from their chloride salts of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) in ethanol. The ligand along with its metal complexes have been characterized on the basis of analytical data, IR, electronic, mass, 1HNMR, ESR spectral data, thermal studies, magnetic susceptibility, and molar conductance measurements. The nonelectrolytic behaviour of the complexes was assessed from the measured low conductance data. The elemental analysis of the complexes confirm the stoichiometry of the type CuL2Cl2 and MLCl2 where M = Ni(II), Co(II), Cd(II), and Hg(II) and L = Schiff base. The redox property of the Cu(II) complex was investigated by electrochemical method using cyclic voltammetry. In the light of these results, Co(II), Ni(II), and Cu(II) complexes are assigned octahedral geometry, Cd(II), and Hg(II) complexes tetrahedral geometry. In order to evaluate the effect of metal ions upon chelation, both the ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleaving capacity of all the complexes was analysed by agarose gel electrophoresis method. PMID:24592203

  18. Transition Metal(II) Complexes with Cefotaxime-Derived Schiff Base: Synthesis, Characterization, and Antimicrobial Studies

    Science.gov (United States)

    Amzoiu, Emilia; Spînu, Cezar Ionuţ

    2014-01-01

    New [ML2(H2O)2] complexes, where M = Co(II), Ni(II), Cu(II), and Zn(II) while L corresponds to the Schiff base ligand, were synthesized by condensation of cefotaxime with salicylaldehyde in situ in the presence of divalent metal salts in ethanolic medium. The complexes were characterized by elemental analyses, conductance, and magnetic measurements, as well as by IR and UV-Vis spectroscopy. The low values of the molar conductance indicate nonelectrolyte type of complexes. Based on spectral data and magnetic moments, an octahedral geometry may be proposed for Co(II), Ni(II), and Zn(II) complexes while a tetragonal geometry for Cu(II) complex. Molecular structure of the Schiff base ligand and its complexes were studied using programs dedicated to chemical modeling and quantomolecular calculation of chemical properties. All the synthesized complexes were tested for in vitro antibacterial activity against some pathogenic bacterial strains, namely Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. The MIC values shown by the complexes against these bacterial strains revealed that the metal complexes possess superior antibacterial activity than the Schiff base. PMID:24688454

  19. Assembly and Properties of Heterobimetallic CoII/III/CaII Complexes with Aquo and Hydroxo Ligands

    OpenAIRE

    Lacy, David C.; Park, Young Jun; Ziller, Joseph W.; Yano, Junko; Borovik, A. S.

    2012-01-01

    The use of water as a reagent in redox-driven reactions is advantageous because it is abundant and environmentally compatible. The conversion of water to dioxygen in photosynthesis illustrates one example, in which a redox-inactive CaII ion and four manganese ions are required for function. In this report we describe the stepwise formation of two new heterobimetallic complexes containing CoII/III and CaII ions, and either hydroxo or aquo ligands. The preparation of a 4-coordinate CoII synthon...

  20. Synthesis, spectroscopic, anticancer and antibacterial studies of Ni(II) and Cu(II) complexes with 2-carboxybenzaldehyde thiosemicarbazone

    Science.gov (United States)

    Chandra, Sulekh; Vandana

    2014-08-01

    Ni(II) and Cu(II) complexes of 2-carboxybenzaldehyde thiosemicarbazone (L) were synthesized and investigated by their spectral and analytical data. These newly synthesized complexes have a composition of M(L)X(H2O)2 (where M = Ni(II), Cu(II) and X = Cl-, NO3-, CH3COO-) and (L) is the tridentate Schiff base ligand. The ligand and its complexes have been characterized on the basis of analytical, molar conductivity, magnetic susceptibility measurements, FT-IR, ESR, 1H NMR and electronic spectral analysis. All the compounds were non-electrolytic in nature. On the basis of spectral studies an octahedral geometry has been assigned for Ni(II) and a tetragonal geometry for Cu(II) complexes. The ligand and its metal complexes were screened for their anticancer studies against human breast cancer cell lines MCF-7 and calculated minimum inhibitory concentration and also for antibacterial activity using Kirby-Bauer single disk susceptibility test.

  1. Coordination behavior of tetraaza [N4] ligand towards Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes: Synthesis, spectroscopic characterization and anticancer activity

    Science.gov (United States)

    El-Boraey, Hanaa A.

    2012-11-01

    Novel eight Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes with [N4] ligand (L) i.e. 2-amino-N-{2-[(2-aminobenzoyl)amino]ethyl}benzamide have been synthesized and structurally characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and molar conductivity measurements. On the basis of IR, mass, electronic and EPR spectral studies an octahedral geometry has been proposed for Co(II), Ni(II) complexes and Cu(II) chloride complex, square-pyramidal for Cu(I) bromide complex. For Cu(II) nitrate complex (6), Pd(II) complex (8) square planar geometry was proposed. The EPR data of Cu(II) complexes in powdered form indicate dx2-y2 ground state of Cu(II) ion. The antitumor activity of the synthesized ligand and some selected metal complexes has been studied. The palladium(II) complex (8) was found to display cytotoxicity (IC50 = 25.6 and 41 μM) against human breast cancer cell line MCF-7 and human hepatocarcinoma HEPG2 cell line.

  2. BIOASSAY STUDIES OF METAL(II) COMPLEXES OF 2,2'-(ETHANE ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Ni(II), Cu(II) and Zn(II) coordination compounds with modified diammine 2,2'-(ethane-1,2- diyldiimino)diacetic acid (EDDA) were prepared and characterized. Coordination complexes of the EDDA were characterized by physical measurements including elemental analysis, IR, UV-Visible, magnetic ...

  3. Assembly and Properties of Heterobimetallic CoII/III/CaII Complexes with Aquo and Hydroxo Ligands

    Science.gov (United States)

    Lacy, David C.; Park, Young Jun; Ziller, Joseph W.; Yano, Junko; Borovik, A. S.

    2012-01-01

    The use of water as a reagent in redox-driven reactions is advantageous because it is abundant and environmentally compatible. The conversion of water to dioxygen in photosynthesis illustrates one example, in which a redox-inactive CaII ion and four manganese ions are required for function. In this report we describe the stepwise formation of two new heterobimetallic complexes containing CoII/III and CaII ions, and either hydroxo or aquo ligands. The preparation of a 4-coordinate CoII synthon was achieved with the tripodal ligand, N,N′,N″-[2,2′,2″-nitrilotris(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamido, [MST]3−. Water binds to [CoIIMST]− to form the 5-coordinate [CoIIMST(OH2)]− complex that was used to prepare the CoII/CaII complex [CoIIMST(μ-OH2)CaII⊂15-crown-5(OH2)]+ ([CoII(μ-OH2)CaIIOH2]+). [CoII(μ-OH2)CaOH2]+ contained two aquo ligands, one bonded to the CaII ion and one bridging between the two metal ions and thus represents an unusual example of a heterobimetallic complex containing 2 aquo ligands spanning different metal ions. Both aquo ligands formed intramolecular hydrogen bonds with the [MST]3− ligand. [CoIIMST(OH2)]− was oxidized to form [CoIIIMST(OH2)] that was further converted to [CoIIIMST(μ-OH)CaII⊂15-crown-5]+ ([CoIII(μ-OH)CaII]+) in the presence of base and CaIIOTf2/15-crown-5. [CoIII(μ-OH)CaII]+ was also synthesized from the oxidation of [CoIIMST]− with PhIO in the presence of CaIIOTf2/15-crown-5. Allowing [CoIII(μ-OH)CaII]+ to react with diphenylhydrazine afforded [CoII(μ-OH2)CaIIOH2]+ and azobenzene. Additionally, the characterization of [CoIII(μ-OH)CaII]+ provides another formulation for the previously reported CoIV–oxo complex, [(TMG3tren)CoIV(μ-O)ScIII(OTf)3]2+ to one that instead could contain a CoIII–OH unit. PMID:22998407

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

    African Journals Online (AJOL)

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

  5. Coordination chemistry of sugar-phosphate complexes with palladium(II), rhenium(V) and zinc(II)

    Energy Technology Data Exchange (ETDEWEB)

    Steinborn, Christian Martin

    2013-05-21

    As described before, some studies dealing with coordination chemistry of sugar phosphates are available but no analogous complexes of Zn{sup II} have been investigated yet. The primary goal of this work is, therefore, to fill this gap. In order to stay close to the active sites of enzymes such as class-II-aldolase, the simple metal fragment Zn{sup II}(dien) is used. NMR spectroscopy is used primarily as analytical method since it enables the investigation of both complex equilibria in solution and pH dependence of metal-binding sites. Since this approach is challenging due to the fast metal-ligand exchange and the absence of CIS values, it is necessary to improve the significance of NMR data collected from sugar-phosphate complexes with Zn{sup II}. Hence, further experiments are performed with molecules similar to sugar phosphates such as reducing and methylated sugars or polyols. Beside NMR spectroscopy, crystal-structure analysis will be used to get more detailed information about the binding pattern of the complexes. Additionally, sugar-phosphate complexes of Pd{sup II} are investigated. Further experiments are conducted, on the one hand, to synthesise more sugarphosphate complexes with ReVON2 fragments, and, on the other hand, to grow crystals confirming the theory about mixed sugar-core-phosphate chelation.

  6. Influence of second sphere hydrogen bonding interaction on a manganese(II)-aquo complex.

    Science.gov (United States)

    El Ghachtouli, Sanae; Guillot, Régis; Dorlet, Pierre; Anxolabéhère-Mallart, Elodie; Aukauloo, Ally

    2012-02-14

    We have developed a pentadentate N(4)O ligand scaffold with a benzimidazole group placed in a rigid fashion to develop hydrogen bonding interaction with the ligand in the sixth position. The mononuclear Mn(II) complex with a water molecule was isolated and characterized. We discuss the role of the outer sphere ligand in stabilising a Mn(II)-aquo complex.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    Indian Academy of Sciences (India)

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

  9. Inside the PS tunnel

    CERN Multimedia

    1974-01-01

    Pre-start work is going on at the end of the PS long shut-down. The photo shows secondary beams drawn from an internal target (bottom) towards South Hall, behind the shielding wall (top) (see also photo 7409012X).

  10. PS Control Room

    CERN Multimedia

    CERN PhotoLab

    1963-01-01

    The good old PS Control Room, all manual. For each parameter, a knob or a button to control it; for each, a light or meter or oscilloscope to monitor it; carefully written pages serve as the data bank; phones and intercom for communication. D.Dekkers is at the microphone, M.Valvini sits in front.

  11. PS auxiliary magnet

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    Units of the PS auxiliary magnet system. The picture shows how the new dipoles, used for vertical and horizontal high-energy beam manipulation, are split for installation and removal so that it is not necessary to break the accelerator vacuum. On the right, adjacent to the sector valve and the windings of the main magnet, is an octupole of the set.

  12. Syntheses, Crystal Structures and Thermal Behaviors of Two Supramolecular Salamo-Type Cobalt(II and Zinc(II Complexes

    Directory of Open Access Journals (Sweden)

    Gang Li

    2017-07-01

    Full Text Available This paper reports the syntheses of two new complexes, [Co(L1(H2O2] (1 and [{Zn(L2(μ-OAcZn(n-PrOH}2] (2, from asymmetric halogen-substituted Salamo-type ligands H2L1 and H3L2, respectively. Investigation of the crystal structure of complex 1 reveals that the complex includes one Co(II ion, one (L12− unit and two coordinated water molecules. Complex 1 shows slightly distorted octahedral coordination geometry, forming an infinite 2D supramolecular structure by intermolecular hydrogen bond and π–π stacking interactions. Complex 2 contains four Zn(IIions, two completely deprotonated (L23− moieties, two coordinated μ-OAc− ions and n-propanol molecules. The Zn(II ions in complex 2 display slightly distorted trigonal bipyramidal or square pyramidal geometries.

  13. Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N-Methyl-N-((pyridin-2-yl)methyl) cyclohexanamine

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Seoung Hyun; Lee, Hyosun [Kyungpook National University, Daegu (Korea, Republic of); Shin, Jongwon [POSTECH, Pohang (Korea, Republic of); Nayab, Saira [Shaheed Benazir Bhutto University, Sheringal (Pakistan)

    2016-05-15

    We demonstrated the synthesis and characterization of Co(II), Cu(II), and Zn(II) complexes ligated to N-methyl-N-((pyridin-2-yl)methyl)cyclohexanamine. The complex [Co(nmpc)Cl{sub 2}] in the presence of MMAO showed the highest catalytic activity for MMA polymerization at 60 °C compared with its Zn(II) and Cu(II) analogs. The metal center showed an obvious influence on the catalytic activity, although this appeared to have no effect on the stereo-regularity of the resultant PMMA. X-ray diffraction analysis revealed that [Co(nmpc)Cl{sub 2}] and [Zn(nmpc)Cl{sub 2}] crystallized in the monoclinic system with space group P2{sub 1}/c and existed as monomeric and solvent-free complexes.

  14. New Mn(II, Ni(II, Cd(II, Pb(II complexes with 2-methylbenzimidazole and other ligands. Synthesis, spectroscopic characterization, crystal structure, magnetic susceptibility and biological activity studies

    Directory of Open Access Journals (Sweden)

    Shayma A. Shaker

    2016-11-01

    Full Text Available Synthesis and characterization of Mn(II, Ni(II, Cd(II and Pb(II mixed ligand complexes of 2-methylbenzimidazole with other ligands have been reported. The structure of the ligands and their complexes was investigated using elemental analysis, IR, UV–Vis, (1H, 13C NMR spectroscopy, molar conductivity and magnetic susceptibility measurements. In all the studies of complexes, the 2-methylbenzimidazole behaves as a neutral monodentate ligand which is coordinated with the metal ions through the N atom. While benzotriazole behaves as a neutral bidentate ligand which is coordinated with the Ni(II ion through the two N atoms. Moreover, the N-acetylglycine behaves as a bidentate ligand which is coordinated with the Mn(II, Ni(II and Pb(II ions through the N atom and the terminal carboxyl oxygen atom. The magnetic and spectral data indicate the tetrahedral geometry for Mn(II complex, irregular tetrahedral geometry for Pb(II complex and octahedral geometry for Ni(II complex. The X-ray single crystal diffraction method was used to confirm a centrosymmetric dinuclear Cd(II complex as each two metal ions are linked by a pair of thiocyanate N = S bridge. Two 2-methylbenzimidazole N-atom donors and one terminal thiocyanate N atom complete a highly distorted square pyramid geometry around the Cd atom. Besides, different cell types were used to determine the inhibitory effect of Mn(II, Ni(II, Cd(II and Pb(II complexes on cell growth using MTT assay. Cd(II complex showed cytotoxic effect on various types of cancer cell lines with different EC50 values.

  15. Six, Seven or Eight Coordinate Fe(II) , Co(II) or Ni(II) Complexes of Amide-Appended Tetraazamacrocycles for ParaCEST Thermometry.

    Science.gov (United States)

    Olatunde, Abiola O; Bond, Christopher J; Dorazio, Sarina J; Cox, Jordan M; Benedict, Jason B; Daddario, Michael D; Spernyak, Joseph A; Morrow, Janet R

    2015-12-07

    Fe(II) , Co(II) and Ni(II) complexes of two tetraazamacrocycles (1,4,8,11-tetrakis(carbamoylmethyl)-1,4,8,11-tetraazacyclotetradecane (L1) and 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane (L2) show promise as paraCEST agents for registration of temperature (paraCEST=paramagnetic chemical exchange saturation transfer). The Fe(II) , Co(II) and Ni(II) complexes of L1 show up to four CEST peaks shifted ≤112 ppm, whereas analogous complexes of L2 show only a single CEST peak at ≤69 ppm. Comparison of the temperature coefficients (CT ) of the CEST peaks of [Co(L2)](2+) , [Fe(L2)](2+) , [Ni(L1)](2+) and [Co(L1)](2+) showed that a CEST peak of [Co(L1)](2+) gave the largest CT (-0.66 ppm (o) C(-1) at 4.7 T). NMR spectral and CEST properties of these complexes correspond to coordination complex symmetry as shown by structural data. The [Ni(L1)](2+) and [Co(L1)](2+) complexes have a six-coordinate metal ion bound to the 1-, 4-amide oxygen atoms and four nitrogen atoms of the tetraazamacrocycle. The [Fe(L2)](2+) complex has an unusual eight-coordinate Fe(II) bound to four amide oxygen atoms and four macrocyclic nitrogen atoms. For [Co(L2)](2+) , one structure has seven-coordinate Co(II) with three bound amide pendents and a second structure has a six-coordinate Co(II) with two bound amide pendents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    Bera, Manindranath; Patra, Ayan

    2011-10-18

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

  17. Surface complexation and oxidation of Sn(II) by nanomagnetite.

    Science.gov (United States)

    Dulnee, Siriwan; Banerjee, Dipanjan; Merkel, Broder J; Scheinost, Andreas C

    2013-11-19

    The long-lived fission product 126Sn is of substantial interest in the context of nuclear waste disposal in deep underground repositories. However, the prevalent redox state, the aqueous speciation as well as the reactions at the mineral-water interface under the expected anoxic and reducing conditions are a matter of debate. We therefore investigated the reaction of Sn(II) with a relevant redox-reactive mineral, magnetite (Fe(II)Fe(III)2O4) at 9 by coadsorption of Fe(II), thereby increasing sorption at this high pH.

  18. SPECIATION OF L-ASPARTIC ACID COMPLEXES OF Co(II), Ni(II ...

    African Journals Online (AJOL)

    Preferred Customer

    0.1 M solutions of Co(II), Ni(II), Cu(II) and Zn(II) nitrates (GR, E-Merck, Germany) were prepared by maintaining 0.05 M acid (HNO3) concentration to suppress the hydrolysis. Acetonitrile (GR, E-Merck) and ethylene glycol (AR, Qualigen) were used as received. 2.0 M sodium nitrate solution was prepared to maintain ionic ...

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

    Science.gov (United States)

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

    2015-01-01

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

  20. Exogenous bridging and nonbridging in Cu (II) complexes of ...

    Indian Academy of Sciences (India)

    The complexes are characterized by elemental analysis, electrochemical and electron paramagnetic spectral studies. Redox properties of the complexes in acetonitrile are highly quasireversible due to the chemical or/and stereochemical changes subsequent to electron transfer. The complexes show resolved copper ...

  1. Single crystal X- and Q-band EPR spectroscopy of a binuclear Mn(2)(III,IV) complex relevant to the oxygen-evolving complex of photosystem II.

    Science.gov (United States)

    Yano, Junko; Sauer, Kenneth; Girerd, Jean-Jacques; Yachandra, Vittal K

    2004-06-23

    The anisotropic g and hyperfine tensors of the Mn di-micro-oxo complex, [Mn(2)(III,IV)O(2)(phen)(4)](PF(6))(3).CH(3)CN, were derived by single-crystal EPR measurements at X- and Q-band frequencies. This is the first simulation of EPR parameters from single-crystal EPR spectra for multinuclear Mn complexes, which are of importance in several metalloenzymes; one of them is the oxygen-evolving complex in photosystem II (PS II). Single-crystal [Mn(2)(III,IV)O(2)(phen)(4)](PF(6))(3).CH(3)CN EPR spectra showed distinct resolved (55)Mn hyperfine lines in all crystal orientations, unlike single-crystal EPR spectra of other Mn(2)(III,IV) di-micro-oxo bridged complexes. We measured the EPR spectra in the crystal ab- and bc-planes, and from these spectra we obtained the EPR spectra of the complex along the unique a-, b-, and c-axes of the crystal. The crystal orientation was determined by X-ray diffraction and single-crystal EXAFS (Extended X-ray Absorption Fine Structure) measurements. In this complex, the three crystallographic axes, a, b, and c, are parallel or nearly parallel to the principal molecular axes of Mn(2)(III,IV)O(2)(phen)(4) as shown in the crystallographic data by Stebler et al. (Inorg. Chem. 1986, 25, 4743). This direct relation together with the resolved hyperfine lines significantly simplified the simulation of single-crystal spectra in the three principal directions due to the reduction of free parameters and, thus, allowed us to define the magnetic g and A tensors of the molecule with a high degree of reliability. These parameters were subsequently used to generate the solution EPR spectra at both X- and Q-bands with excellent agreement. The anisotropic g and hyperfine tensors determined by the simulation of the X- and Q-band single-crystal and solution EPR spectra are as follows: g(x) = 1.9887, g(y) = 1.9957, g(z) = 1.9775, and hyperfine coupling constants are A(III)(x) = |171| G, A(III)(y) = |176| G, A(III)(z) = |129| G, A(IV)(x) = |77| G, A

  2. Micellar effect on metal-ligand complexes of Co(II, Ni(II, Cu(II and Zn(II with citric acid

    Directory of Open Access Journals (Sweden)

    Nageswara Rao Gollapalli

    2009-12-01

    Full Text Available Chemical speciation of citric acid complexes of Co(II, Ni(II, Cu(II and Zn(II was investigated pH-metrically in 0.0-2.5% anionic, cationic and neutral micellar media. The primary alkalimetric data were pruned with SCPHD program. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. Alkalimetric titrations were carried out in different relative concentrations (M:L:X = 1:2:5, 1:3:5, 1:5:3 of metal (M to citric acid. The selection of best chemical models was based on statistical parameters and residual analysis. The species detected were MLH, ML2, ML2H and ML2H2. The trend in variation of stability constants with change in mole fraction of the medium is explained on the basis of electrostatic and non-electrostatic forces. Distributions of the species with pH at different compositions of micellar media are also presented.

  3. Speciation of L-aspartic acid complexes of Co(II), Ni(II), Cu(II) and Zn ...

    African Journals Online (AJOL)

    The models for the binary species contained ML2H2, ML2H and ML2 for Co(II) and Zn(II), ML, ML2H2 and ML2 for Ni(II) and Cu(II) in acetonitrile- and ethylene glycol-water mixtures. The trend in variation of stability constants with change in the dielectric constant of the medium was explained on the basis of electrostatic and ...

  4. Cr(III,Mn(II,Fe(III,Co(II,Ni(II,Cu(II and Zn(II Complexes with Diisobutyldithiocarbamato Ligand

    Directory of Open Access Journals (Sweden)

    Mohammad Tarique

    2011-01-01

    Full Text Available The synthesis of sulphur and nitrogen containing dithiocarbamato ligand derived from diisobutylamine as well as its coordination compounds with 3d series transition metals is presented. These synthesized compounds were characterized on the basis of elemental analysis, conductometric measurements and IR spectral studies. The analytical data showed the stoichiometry 1:2 and 1:3 for the compounds of the types ML2 {M=Mn(II, Co(II, Ni(II, Cu(II and Zn(II} and M'L3{M'=Cr(III and Fe(III} respectively. The conductometric measurements proved the non-electrolytic behaviour of all the compounds. The bidentate nature of dithiocarbamato moiety was confirmed on the basis of IR spectral data.

  5. Synthesis, characterization and biocidal activity of some transition metal(II) complexes with isatin salicylaldehyde acyldihydrazones.

    Science.gov (United States)

    Singh, Vinod P; Singh, Shweta; Singh, Divya P

    2012-06-01

    Cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes with two new unsymmetrical ligands, isatin salicylaldehyde oxalic acid dihydrazide (isodh) and isatin salicylaldehyde malonic acid dihydrazide (ismdh) were synthesized and characterized by elemental analyses, electrical conductance, magnetic moments, electronic, NMR, ESR and IR spectral studies. The isodh acts as a dibasic tetra dentate ligand bonding through two >C=N-, a deprotonated phenolate and deprotonated indole enolate groups to the metal. The ismdh ligand shows monobasic tetra dentate behaviour in bonding with metal ion through two >C=N-, indole >C=O and a deprotonated phenolate group. The electronic spectral data suggest 4-coordinate square planar geometry for Co(II), Ni(II) and Cu(II) complexes of isodh, whereas, 6-coordinate octahedral structure for the ismdh complexes. The ESR studies also indicate a square planar and distorted octahedral environment around Cu(II) for isodh and ismdh complexes, respectively. Most of the metal complexes show better antifungal activity than the standard and a significant antibacterial activity against various fungi and bacteria.

  6. Docking and molecular dynamics simulations of the ternary complex nisin2:lipid II

    Science.gov (United States)

    Mulholland, Sam; Turpin, Eleanor R.; Bonev, Boyan B.; Hirst, Jonathan D.

    2016-01-01

    Lanthionine antibiotics are an important class of naturally-occurring antimicrobial peptides. The best-known, nisin, is a commercial food preservative. However, structural and mechanistic details on nisin-lipid II membrane complexes are currently lacking. Recently, we have developed empirical force-field parameters to model lantibiotics. Docking and molecular dynamics (MD) simulations have been used to study the nisin2:lipid II complex in bacterial membranes, which has been put forward as the building block of nisin/lipid II binary membrane pores. An Ile1Trp mutation of the N-terminus of nisin has been modelled and docked onto lipid II models; the computed binding affinity increased compared to wild-type. Wild-type nisin was also docked onto three different lipid II structures and a stable 2:1 nisin:lipid II complex formed. This complex was inserted into a membrane. Six independent MD simulations revealed key interactions in the complex, specifically the N-terminal engagement of nisin with lipid II at the pyrophosphate and C-terminus of the pentapeptide chain. Nisin2 inserts into the membrane and we propose this as the first step in pore formation, mediated by the nisin N-terminus–lipid II pentapeptide hydrogen bond. The lipid II undecaprenyl chain adopted different conformations in the presence of nisin, which may also have implications for pore formation. PMID:26888784

  7. Physiological consequences of complex II inhibition for aging, disease, and the mKATP channel.

    Science.gov (United States)

    Wojtovich, Andrew P; Smith, C Owen; Haynes, Cole M; Nehrke, Keith W; Brookes, Paul S

    2013-05-01

    In recent years, it has become apparent that there exist several roles for respiratory complex II beyond metabolism. These include: (i) succinate signaling, (ii) reactive oxygen species (ROS) generation, (iii) ischemic preconditioning, (iv) various disease states and aging, and (v) a role in the function of the mitochondrial ATP-sensitive K(+) (mKATP) channel. This review will address the involvement of complex II in each of these areas, with a focus on how complex II regulates or may be involved in the assembly of the mKATP. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease. Copyright © 2012. Published by Elsevier B.V.

  8. Joint toxicity of tetracycline with copper(II) and cadmium(II) to Vibrio fischeri: effect of complexation reaction.

    Science.gov (United States)

    Tong, Fei; Zhao, Yanping; Gu, Xueyuan; Gu, Cheng; Lee, Charles C C

    2015-03-01

    Co-contamination of antibiotic and heavy metals commonly occurs in the environment. Tetracycline (TC), a common antibiotic, can behave as an efficient organic ligand to complex with cations. In this paper, the joint toxicity of TC with two commonly existing metals, copper(II) and cadmium(II), towards a luminescent bacteria, Vibrio fischeri, are investigated. Results showed that coexistence of TC and Cu(II) showed a significant antagonistic effect, while TC and Cd(II) showed a synergistic effect. The aqueous speciation of TC with two metal cations was calculated using a chemical equilibrium software Visual MINTEQ and results indicated that a strong complexation exist between TC and Cu(II), while much weaker interaction between TC and Cd(II). Traditional joint toxicity prediction model based on independent action failed to predict the combined toxicity of TC with metals. A new method based on speciation calculation was used to evaluate the joint toxicity of ligands and cations. It is assumed that the metal-ligand complexes are non-toxic to V. fischeri and the joint toxicity is determined by the sum of toxic unit of free metal-ions and free organic ligands. It explained the joint toxicity of the mixed systems reasonably well. Meanwhile, citric acid (CA) and fulvic acid (FA) were also introduced in this study to provide a benchmark comparison with TC. Results showed it is also valid for mixed systems of CA and FA with metals except for the Cd-CA mixture.

  9. PS injection area

    CERN Multimedia

    1974-01-01

    Looking against the direction of protons in the main ring (left): the beam coming from the linac 1 either goes to the booster (on the right) or is deflected towards the PS to be directly injected into section 26 (facing the camera). Also shown the start of the TT2 line, ejected from straight section 16 to go towards the ISR passing over the beam line from the linac. (see Photo Archive 7409009)

  10. PS injection area

    CERN Multimedia

    1974-01-01

    To the right is the PS ring viewed along the direction of the protons. At the left the injection line coming from the 50 MeV Linac 1 (bottom) and going towards the 800 MeV booster, or deflected to the right to be injected directly into straight section 16. The drumlike element behind the (blue) dipole magnet is a 'debuncher' (a 200 MHz cavity). See photos 7409014X and 7409009.

  11. Ni(II, Pd(II and Pt(II complexes with ligand containing thiosemicarbazone and semicarbazone moiety: synthesis, characterization and biological investigation

    Directory of Open Access Journals (Sweden)

    SULEKH CHANDRA

    2008-07-01

    Full Text Available The synthesis of nickel(II, palladium(II and platinum(II complexes with thiosemicarbazone and semicarbazone of p-tolualdehyde are reported. All the new compounds were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, 1H-NMR, IR and electronic spectral studies. Based on the molar conductance measurements in DMSO, the complexes may be formulated as [Ni(L2Cl2] and [M(L2]Cl2 (where M = Pd(II and Pt(II due to their non-electrolytic and 1:2 electrolytic nature, respectively. The spectral data are consistent with an octahedral geometry around Ni(II and a square planar geometry for Pd(II and Pt(II, in which the ligands act as bidentate chelating agents, coordinated through the nitrogen and sulphur/oxygen atoms. The ligands and their metal complexes were screened in vitro against fungal species Alternaria alternata, Aspergillus niger and Fusarium odum, using the food poison technique.

  12. Dinuclear mixed-valence Co(III)Co(II) complexes derived from a macrocyclic ligand: unique example of a Co(III)Co(II) complex showing catecholase activity.

    Science.gov (United States)

    Majumder, Samit; Mondal, Suraj; Lemoine, Pascale; Mohanta, Sasankasekhar

    2013-04-07

    The work in this paper presents the syntheses, characterization, catecholase activity, and electrospray ionization mass spectroscopic (ESI-MS positive) study of three mixed-valence dinuclear Co(III)Co(II) complexes of composition [Co(III)Co(II)L(N(3))(3)]·CH(3)CN (1), [Co(III)Co(II)L(OCN)(3)]·CH(3)CN (2), and [Co(III)Co(II)L(μ-CH(3)COO)(2)](ClO(4)) (3), derived from a tetraimino diphenolate macrocyclic ligand H(2)L, obtained on [2 + 2] condensation of 4-ethyl-2,6-diformylphenol and 2,2'-dimethyl-1,3-diaminopropane. While 1 and 2 are diphenoxo-bridged, 3 is a heterobridged bis(μ-phenoxo)bis(μ-acetate) system. Utilizing 3,5-di-tert-butyl catechol (3,5-DTBCH(2)) as the substrate, the catecholase activity of all the three complexes has been checked in methanol/acetonitrile/N,N-dimethyl formamide. While 2 and 3 are inactive, complex 1 shows catecholase activity with turnover numbers of 482.16 h(-1) and 45.38 h(-1) in acetonitrile and methanol, respectively. Electrospray ionization mass (ESI-MS positive) spectra of complexes 1-3 have been recorded in acetonitrile solutions and the positive ions have been well characterized. The ESI-MS positive spectrum of complex 1 in the presence of 3,5-DTBCH(2) has also been recorded and, interestingly, two positive ions [Co(III)Co(II)L(N(3))(2)(3,5-DTBCH(-))H](+) and [Co(II)Co(II)L(μ-3,5-DTBCH(2-))Na](+) have been identified.

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

    Science.gov (United States)

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

    2017-03-10

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

  14. Spectroscopic and biological approach of Ni(II), Cu(II) and Co(II) complexes of 4-methoxy/ethoxybenzaldehyde thiosemicarbazone glyoxime

    Science.gov (United States)

    Babahan, Ilknur; Eyduran, Fatih; Coban, Esin Poyrazoglu; Orhan, Nil; Kazar, Didem; Biyik, Halil

    2014-03-01

    Two novel vicinal dioxime ligands containing (4-methoxybenzaldehyde thiosemicarbazone glyoxime (L1H2) or 4-ethoxybenzaldehyde thiosemicarbazone glyoxime (L2H2)) thiosemicarbazone units were synthesized and characterized using 1H NMR, 13C NMR, HMQC, MS, infrared and, UV-VIS. spectroscopy, elemental analysis, and magnetic susceptibility measurements. Mononuclear nickel(II), copper(II) and cobalt(II) complexes with a metal:ligand ratio of 1:2 for L1H2 and L2H2 were also synthesized. The effect of pH and solvent on the absorption spectra of both ligands and complexes was determined. IR spectra show that the ligands act in a bidentate manner and coordinates N4 donor groups of the ligands to NiII, CuII and CoII ions. The detection of H-bonding (Osbnd H⋯O) in the [M(LH)2] metal complexes by IR spectra supported the square-planar MN4 coordination of mononuclear complexes. The antimicrobial activities of compounds L1H2 , L2H2 , and their Ni(II), Cu(II) and Co(II) complexes were evaluated using the disc diffusion method against 12 bacteria and 4 yeasts. The minimal inhibitory concentrations (MICs) against 7 bacteria and 3 yeasts were also determined. Among the test compounds attempted, L1H2 , [Ni(L1H)2 ], [Cu(L1H)2 ], L2H2 , [Ni(L2H)2 ] and [Cu(L2H)2 ] showed some activities against certain Gram-positive bacteria and some of the yeasts tested.

  15. Synthesis, Characterization and Biological Activities of Cu(II, Co(II, Mn(II, Fe(II, and UO2(VI Complexes with a New Schiff Base Hydrazone: O-Hydroxyacetophenone-7-chloro-4-quinoline Hydrazone

    Directory of Open Access Journals (Sweden)

    Nora H. Al-Shaalan

    2011-10-01

    Full Text Available The Schiff base hydrazone ligand HL was prepared by the condensation reaction of 7-chloro-4-quinoline with o-hydroxyacetophenone. The ligand behaves either as monobasic bidentate or dibasic tridentate and contain ONN coordination sites. This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II, Ni(II, Co(II, Mn(II, UO2 (VI and Fe(II to form either mono- or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, Mass, and UV-Visible spectra. The magnetic moments and electrical conductance of the complexes were also determined. The Co(II, Ni(II and UO2 (VI complexes are mononuclear and coordinated to NO sites of two ligand molecules. The Cu(II complex has a square-planar geometry distorted towards tetrahedral, the Ni(II complex is octahedral while the UO2 (VI complex has its favoured heptacoordination. The Co(II, Mn(II complexes and also other Ni(II and Fe(III complexes, which were obtained in the presence of Li(OH as deprotonating agent, are binuclear and coordinated via the NNNO sites of two ligand molecules. All the binuclear complexes have octahedral geometries and their magnetic moments are quite low compared to the calculated value for two metal ions complexes and thus antiferromagnetic interactions between the two adjacent metal ions. The ligand HL and metal complexes were tested against a strain of Gram +ve bacteria (Staphylococcus aureus, Gram −ve bacteria (Escherichia coli, and fungi (Candida albicans. The tested compounds exhibited high antibacterial activities.

  16. Synthesis and crystal structure of a polymeric zinc(II) complex ...

    African Journals Online (AJOL)

    A new polymeric zinc(II) complex, [ZnL2(PDA)]n, has been prepared by the reaction of zinc sulfate, 4-nitrophenylacetic acid, and propane-1,3-diamine (PDA) in water. Structure of the complex has been characterized by single-crystal X-ray diffraction. The complex crystallizes as orthorhombic space group Pnma, with unit cell ...

  17. Complexation Effect on Redox Potential of Iron(III)-Iron(II) Couple: A Simple Potentiometric Experiment

    Science.gov (United States)

    Rizvi, Masood Ahmad; Syed, Raashid Maqsood; Khan, Badruddin

    2011-01-01

    A titration curve with multiple inflection points results when a mixture of two or more reducing agents with sufficiently different reduction potentials are titrated. In this experiment iron(II) complexes are combined into a mixture of reducing agents and are oxidized to the corresponding iron(III) complexes. As all of the complexes involve the…

  18. Nickel(II) complexes containing ONS donor ligands: Synthesis ...

    Indian Academy of Sciences (India)

    that the complexes possess a distorted octahedral geometry with the ligand coordinating in a uni-negative tri- dentate ONS fashion. The catalytic activity of complexes towards some C–C ... gen, nitrogen and sulfur was carried out using Vario EL. III Elemental analyzer at SAIF - Cochin India. The IR spectra of the ligand and ...

  19. Application of bisphosphomide-palladium (II) pincer complex in ...

    Indian Academy of Sciences (India)

    The bisphosphomide-based pincer complex [PdBr{2,6-{Ph2PC(O)}2(C6H3)}] (2) has shown very high catalytic activity in Suzuki-Miyaura cross coupling reaction under microwave irradiation for a variety of aryl bromides and aryl boronic acids. The complex showed the same efficiency for gram scale reactions.

  20. Mixed-ligand complexes of ruthenium (II) incorporating a diazo ...

    Indian Academy of Sciences (India)

    Binding of these complexes with calf thymus DNA (CT-DNA) has been investigated by absorption spectroscopy, steady-state emission spectroscopy and viscosity measurements. The experimental results indicate that the size and shape of the intercalating ligands have marked effect on the binding affinity of the complexes ...

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

    African Journals Online (AJOL)

    B. S. Chandravanshi

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

  2. Copper(II Complexes with Ligands Derived from 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one: Synthesis and Biological Activity

    Directory of Open Access Journals (Sweden)

    Raluca Cernat

    2006-11-01

    Full Text Available The synthesis of Cu(II complexes derived from Schiff base ligands obtainedby the condensation of 2-hydroxybenzaldehyde or terephtalic aldehyde with 4-amino-antipyrine (4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one is presented. The newlyprepared compounds were characterized by 1H-NMR, UV-VIS, IR and ESRspectroscopy. The determination of the antimicrobial activity of the ligands and of thecomplexes was carried out on samples of Escherichia coli, Klebsiella pneumoniae,Acinetobacter boumanii, Pseudomonas aeruginosa, Staphylococcus aureus and Candidasp. The qualitative and quantitative antimicrobial activity test results proved that all theprepared complexes are very active, especially against samples of Ps. aeruginosa, A.Boumanii, E. coli and S. aureus.

  3. Synthesis and crystal structure of an iron(II) dimeric complex

    OpenAIRE

    Roy, Partha; Dhara, Koushik; Chakraborty, Jishnunil; Nethaji, Munirathinam; Banerjee, Pradyot

    2007-01-01

    An iron(II) complex, $[Fe_2(salen)_2]$ has been prepared by the reaction of $[Fe^{III}(salen)Cl]$ with copper(II) malonate dihydrate [salen = N,N'-ethylenebis(salicylideneiminato) dianion] in N,N-dimethylformamide-water mixture. The complex has been characterized by FT-IR spectroscopy, UV-vis spectra, thermogravimetric analysis, cyclic voltammetry and X-ray crystallography. The iron(II) complex 1 crystallizes in the monoclinic, space group C2/c, a = 26.664(5) \\AA, b = 6.9943(11) \\AA, c = 14.7...

  4. Synthesis, spectroscopic characterization, DNA interaction and biological activities of Mn(II), Co(II), Ni(II) and Cu(II) complexes with [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol

    Science.gov (United States)

    Gaber, Mohamed; El-Wakiel, Nadia A.; El-Ghamry, Hoda; Fathalla, Shaimaa K.

    2014-11-01

    Manganese(II), cobalt(II), nickel(II) and copper(II) complexes of [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol have been synthesized. The structure of complexes have been characterized by elemental analysis, molar conductance, magnetic moment measurements and spectral (IR, 1H NMR, EI-mass, UV-Vis and ESR), and thermal studies. The results showed that the chloro and nitrato Cu(II) complexes have octahedral geometry while Ni(II), Co(II) and Mn(II) complexes in addition to acetato Cu(II) complex have tetrahedral geometry. The possible structures of the metal complexes have been computed using the molecular mechanic calculations using the hyper chem. 8.03 molecular modeling program to confirm the proposed structures. The kinetic and thermodynamic parameters of the thermal decomposition steps were calculated from the TG curves. The binding modes of the complexes with DNA have been investigated by UV-Vis absorption titration. The results showed that the mode of binding of the complexes to DNA is intercalative or non-intercalative binding modes. Schiff base and its metal complexes have been screened for their in vitro antimicrobial activities against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli and Pesudomonas aeruginosa), fungi (Asperigllus flavus and Mucer) and yeast (Candida albicans and Malassezia furfur).

  5. Designer ligands. Part 14. Novel Mn(lI), Ni(II) and Zn(II) complexes of benzamide- and biphenyl-derived ligands

    CSIR Research Space (South Africa)

    Wellington, Kevin W

    2009-01-01

    Full Text Available geometries. The catecholase activity of the manganese(II) complexes has also been evaluated. Keywords: Manganese(II), nickel(II) and zinc(II) complexes, biomimetic ligands, catalysis Introduction Metals play important roles in biological systems... and, in earlier papers, we have described the development of biomimetic complexes designed to mimic the active site of tyrosinase,1 an enzyme capable of ortho-hydroxylating phenols (phenolase activity) and oxidising catechols to ortho...

  6. Preparation and Spectral Properties of Mixed-Ligand Complexes of VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II with Dimethylglyoxime and N-acetylglycine

    Directory of Open Access Journals (Sweden)

    Shayma A. Shaker

    2010-01-01

    Full Text Available A number of mixed-ligand complexes of the general formula [M(D(G] where D=dimethylglyoximato monoanion, G=N-acetylglycinato and M=VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II were prepared. Each complex was characterized by elemental analysis, determination of metal, infrared spectra, electronic spectra, (1H and 13C NMR spectra, conductivity and magnetic moments. All these complexes were not soluble in some of the organic solvent but highly soluble in dimethylformamide. The conductivity data showed the non-electrolytic nature of the complexes. The electronic spectra exhibited absorption bands in the visible region caused by the d-d electronic transition such as VO(IV, Ni(II and Pd(II. The IR and (1H, 13C NMR spectra which have indicate that the dimethylglyoxime was coordinated with the metal ions through the N and O atoms of the oxime group and N-acetylglycine was coordinated with metal ions through the N atom and terminal carboxyl oxygen atom.

  7. Two polymeric metal complexes based on polycarbazole containing complexes of 8-hydroxyquinoline with Zn(II) and Ni(II) in the backbone: Synthesis, characterization and photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Deng Jinyan; Guo Lihui; Xiu Qian; Zhang Lirong; Wen Gaojun [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Xiangtan University, College of Chemistry, Xiangtan, Hunan 411105 (China); Zhong Chaofan, E-mail: zhongcf798@yahoo.com.cn [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Xiangtan University, College of Chemistry, Xiangtan, Hunan 411105 (China)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We have synthesized two photosensitizers of D-{pi}-A polymeric metal complexes. Black-Right-Pointing-Pointer The polymeric metal complexes possess excellent thermal stability and good open-circuit voltages. Black-Right-Pointing-Pointer The application of the photosensitizers in dye-sensitized solar cells was investigated. Black-Right-Pointing-Pointer The polymeric metal complex containing d{sup 10} Zn(II) exhibited better device performance than that containing low spin d{sup 8} Ni(II). - Abstract: Two novel polymeric metal complexes PZn(Q){sub 2}-C and PNi(Q){sub 2}-C based on polycarbazole containing complexes of 8-hydroxyquinoline with Zn(II) and Ni(II) were synthesized and applied in dye-sensitized solar cells (DSSCs) as photosensitizers. They possess moderate thermal stability and good open-circuit voltages, and the power conversion efficiency of them reached to 1.11% and 0.45%, respectively, under simulated AM 1.5 G solar irradiation (100 mW cm{sup -2}), which shows a new strategy to design photosensitizers for DSSCs.

  8. Unsymmetrical Mesoporphyrinic Complexes of Copper (II and Zinc (II. Microwave-Assisted Synthesis, Spectral Characterization and Cytotoxicity Evaluation

    Directory of Open Access Journals (Sweden)

    Rica Boscencu

    2011-06-01

    Full Text Available New unsymmetrical mesoporphyrinic complexes, namely 5-(4-hydroxyphenyl-10,15,20–tris-(4-carboxymethylphenyl–21,23-Zn(II-porphine and 5-(4-hydroxyphenyl-10,15,20–tris-(4-carboxymethylphenyl–21,23-Cu(II-porphine, were synthesized using a microwave irradiation method. The structures of the porphyrinic complexes were confirmed using FT-IR, UV–Vis, EPR and NMR spectral data. The spectral absorption and emission properties of the porphyrinic complexes were studied in organic solvents of different polarities and the influence of solvent polarity on the wavelengths of the absorbance and fluorescence band maxima is described. The cytotoxicity evaluation of the porphyrinic complexes was performed on human colon adenocarcinoma cell line HT29 for different doses and incubation times. The obtained result indicates a lack of or low toxicity for both compounds, thus recommending them for further testing in light activation protocols.

  9. Bis(. eta. sup 6 -hexamethylbenzene)(. eta. sup 6 ,. eta. sup 6 -polycyclic aromatic)diruthenium(II,II) complexes and their two-electron reduction to cyclohexadienyl anion complexes

    Energy Technology Data Exchange (ETDEWEB)

    Plitzko, K.; Wehrle, G.; Gollas, B.; Rapko, B.; Dannheim, J.; Boekelheide, V. (Univ. of Oregon, Eugene (USA))

    1990-08-29

    The bis({eta}{sup 6}-hexamethylbenzene)({eta}{sup 6},{eta}{sup 6}-polycyclic aromatic)diruthenium(II,II) complexes where the polycyclic aromatic ligands are phenanthrene, 9,10-dihydrophenanthrene, biphenyl, 3,3{prime},5,5{prime}-tetramethylbiphenyl, 4,5,9,10-tetrahydropyrene, and triphenylene, respectively, have been synthesized and their electrochemical properties measured. A two-electron chemical reduction of each of these 4+ diruthenium complexes has led to the isolation and characterization of each of their corresponding 2+ diruthenium complexes. On the basis of analyses of their {sup 1}H and {sup 13}C NMR spectra, structural assignments have been made for all of these 2+ diruthenium complexes.

  10. Magnetochemistry of Model Complexes for the Water Oxidation Center of Photosystem II and High Nuclearity Manganese Complexes.

    Science.gov (United States)

    Tsai, Hui-Lien

    1995-01-01

    Several polynuclear oxo-bridged manganese compounds have been synthesized, and their structural, magnetic, and spectroscopic properties have been characterized. The tetranuclear complexes have been investigated as models of the manganese cluster in the water oxidation center of photosystem II. As the nuclearity increases, manganese complexes are no longer good model complexes. However, they exhibit interesting magnetic properties. Some have high spin ground states as a result of the spin frustration mechanism, or they show some quite unusual properties, such as relaxation behavior shown in superparamagnetic materials. The work described in this thesis focuses on characterizing the electronic structure of polynuclear manganese complexes that have from three to twelve manganese atoms. Of the complexes synthesized, (Mn_3 O(O_2C_2Cl _3)(HO_2CMe) _2(H_2O)) crystallizes in triclinic space group P1 and possesses asymmetric Mn_3 units and is a valence trapped Mn^{II}Mn^ {III}_2 complex. Variable temperature magnetic susceptibility studies have been performed for four trinuclear Mn complexes. The ground state is calculated to have S = 3/2 or S = 1/2 for rm Mn^ {II}Mn^{III}_2 complexes. The Mn^{III} _3 complexes have S = 0 ground state. By changing the ratio of the exchange interaction constant in a Mn_3O complex, it is possible to stabilize ground states with different total spin S _{T} for a rm Mn^{II}Mn^{III} _2 complex. The Mn_4 cubane complexes have been characterized to have an S = 9/2 ground state. Changing the mu_3-bridging ligand or the terminal ligand does not change the ground state of the cubane complexes. The cubane complexes show appreciable zero-field splitting thus have a large anisotropy energy. Because of this relaxation process be seen in theses molecules and shows an out-of-phase component in the AC susceptibility. Mn _8 and Mn_9 clusters show S = 11 and S = 3 ground state respectively. Neutral an reduced Mn_{12} complexes were also synthesized. All of

  11. Oxidation of a dinuclear manganese(II) complex to an oxide-bridged dimanganese(IV) complex

    DEFF Research Database (Denmark)

    Lennartson, A.; McKenzie, C. J.

    2012-01-01

    -2(C15H16N3O2)(2)(H2O)(2)](CF3O3S)(2)center dot 2H(2)O, (II), form binuclear seven-coordinate complexes. Oxidation of (II) with ammonium hexanitratocerate(IV), (NH4)(2)[Ce(NO3)(6)], gave the oxide-bridged dimanganese(IV) complex di-mu-oxido-bis(bis3-[bis(pyridin-2-ylmethyl) amino] propionato...... manganese(IV)) bis[triaquatetranitratocerate(IV)], [Mn2O2(C15H16N3O2)(2)][Ce(NO3)(4)(H2O)(3)](2), (III). The manganese complexes in (II) and (III) sit on a site of (1) over bar symmetry....

  12. General synthesis of di-mu-oxo dimanganese complexes as functional models for the oxygen evolving complex of photosystem II.

    Science.gov (United States)

    Chen, Hongyu; Tagore, Ranitendranath; Das, Siddhartha; Incarvito, Christopher; Faller, J W; Crabtree, Robert H; Brudvig, Gary W

    2005-10-17

    A series of complexes with the formula [Mn(III/IV)2(mu-O)2(L)2(X)2]3+ have been prepared in situ from Mn(II)LCl2 precursors by a general preparative method (L = terpy, Cl-terpy, Br-terpy, Ph-terpy, tolyl-terpy, mesityl-terpy, t Bu3-terpy, EtO-terpy, py-phen, dpya, Me2N-terpy, or HO-terpy, and X = a labile ligand such as water, chloride, or sulfate). The parent complex, where L = terpy and X = water, is a functional model for the oxygen-evolving complex of photosystem II (Limburg, et al. J. Am. Chem. Soc. 2001, 123, 423-430). Crystals of Mn(II)(dpya)Cl2, Mn(II)(Ph-terpy)Cl2, Mn(II)(mesityl-terpy)Cl2, and an organic-soluble di-mu-oxo di-aqua dimanganese complex, [Mn(III/)(IV)2(mu-O)2(mesityl-terpy)2(OH2)2](NO3)3, were obtained and characterized by X-ray crystallography. Solutions of the in situ-formed di-mu-oxo dimanganese complexes were characterized by electrospray mass spectrometry, EPR spectroscopy, and UV-visible spectroscopy, and the rates of catalytic oxygen-evolving activity were assayed. The use of Mn(II)LCl2 precursors leads to higher product purity of the Mn dimers while achieving the 1:1 ligand to Mn stoichiometry appropriate for catalytic activity assay. These methods can be used to screen the catalytic activity of other di-mu-oxo dimanganese complexes generated by using a ligand library.

  13. XANES, EXAFS and Kbeta spectroscopic studies of the oxygen-evolving complex in Photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Robblee, John Henry [Univ. of California, Berkeley, CA (United States)

    2000-12-01

    possible oxidation states of Mn in the S0 state. The dichroic nature of X-rays from synchrotron radiation and single-crystal Mn complexes have been exploited to selectively probe Mn-ligand bonds using XANES and EXAFS spectroscopy. The results from single-crystal Mn complexes show that dramatic dichroism exists in these complexes, and are suggestive of a promising future for single-crystal studies of PS II.

  14. Polypyridyl iron(II) complexes showing remarkable photocytotoxicity ...

    Indian Academy of Sciences (India)

    immortalized human keratinocyte cells HaCaT and breast cancer cell line MCF-7 giving IC50 values of 0.08 and 13 μM in visible light (400–700 ... [Fe(BHA)(L)Cl] of a dipicolylamine derivative (L) and benzhydroxamic acid (HBHA) which ... μM in various cancer cell lines.31 The iron(II) com- plexes showing the BLM activity ...

  15. Co(II), Ni(II) and Cu(II) complexes with coumarin-8-yl Schiff-bases: Spectroscopic, in vitro antimicrobial, DNA cleavage and fluorescence studies

    Science.gov (United States)

    Patil, Sangamesh A.; Unki, Shrishila N.; Kulkarni, Ajaykumar D.; Naik, Vinod H.; Badami, Prema S.

    2011-09-01

    A new series of Co(II), Ni(II) and Cu(II) complexes of the type ML·2H 2O of Schiff-bases derived from m-substituted thiosemicarbazides and 8-acetyl-7-hydroxy-4-methylcoumarin have been synthesized and characterized by spectroscopic studies. Schiff-bases exhibit thiol-thione tautomerism wherein sulphur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, FAB-mass, ESR and fluorescence), magnetic and thermal studies. The low molar conductance values in DMF indicate that, the metal complexes are non-electrolytes. The cyclic voltammetric studies suggested that, the Cu(II) and Ni(II) complexes are of single electron transfer quasi-reversible nature. The Schiff-bases and its metal complexes have been evaluated for their in vitro antibacterial ( Escherichia coli, Staphilococcus aureus, Bascillus subtilis and Salmonella typhi) and antifungal activities ( Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The Schiff-base I and its metal complexes exhibited DNA cleavage activity on isolated DNA of A. niger.

  16. Acceptors in II-IV Semiconductors - Incorporation and Complex Formation

    CERN Multimedia

    2002-01-01

    A strong effort is currently devoted to the investigation of defects and the electrical activation of dopant atoms in II-VI semiconductors. In particular, the knowledge about the behaviour of acceptors, prerequisite for the fabrication of p-type semiconductors, is rather limited. The perturbed $\\,{\\gamma\\gamma}$ -angular correlation technique (PAC) and the photoluminescence spectroscopy (PL) using the radioactive isotopes $^{77}\\!$Br and $^{111}\\!$Ag will be applied for investigating the behaviour of acceptor dopant atoms and their interactions with defects in II-VI semiconductors. The main topic will be the identification of the technical conditions for the incorporation of electrically active acceptors in the II-VI semiconductors ~ZnS, ZnSe, ZnTe, CdS, CdSe, and CdTe with particular emphasis on the compounds~ CdTe, ZnSe, and ZnTe. The investigations will be supplemented by first exploratory PL experiments with the group V acceptors $^{71}\\!$As and $^{121}\\!$Sb. With help of the probe $^{111}\\!$Ag, the pos...

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

    Science.gov (United States)

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

    1999-09-28

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

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

    Science.gov (United States)

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-01

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

  19. Catalytic enantioselective conjugate addition of diethylzinc using NiII-DAIB complexes

    NARCIS (Netherlands)

    Jansen, Johan F.G.A.; Feringa, Bernard

    The conjugate addition of diethylzinc to chalcone, catalyzed by a NiII complex of the chiral aminoalcohol (-)-DAIB, resulted in the formation of (R)-1,3-diphenyl-penta-1-one with enantiomeric excess up to 85%.

  20. Leukoencephalopathy due to Complex II Deficiency and Bi-Allelic SDHB Mutations

    DEFF Research Database (Denmark)

    Grønborg, Sabine; Darin, Niklas; Miranda, Maria J

    2017-01-01

    Isolated complex II deficiency is a rare cause of mitochondrial disease and bi-allelic mutations in SDHB have been identified in only a few patients with complex II deficiency and a progressive neurological phenotype with onset in infancy. On the other hand, heterozygous SDHB mutations are a well......-known cause of familial paraganglioma/pheochromocytoma and renal cell cancer. Here, we describe two additional patients with respiratory chain deficiency due to bi-allelic SDHB mutations. The patients' clinical, neuroradiological, and biochemical phenotype is discussed according to current knowledge...... on complex II and SDHB deficiency and is well in line with previously described cases, thus confirming the specific neuroradiological presentation of complex II deficiency that recently has emerged. The patients' genotype revealed one novel SDHB mutation, and one SDHB mutation, which previously has been...

  1. Conformational transition of DNA by dinuclear Pt(II) complexes causes cooperative inhibition of gene expression

    Science.gov (United States)

    Shimizu, Yuta; Yoshikawa, Yuko; Kenmotsu, Takahiro; Komeda, Seiji; Yoshikawa, Kenichi

    2017-06-01

    Recently, it was reported that a cationic tetrazolato-bridged dinuclear Pt(II) complex, 5-H-Y, is a promising anticancer drug candidate. Here, we investigated the effects of a series of tetrazolato-bridged dinuclear Pt(II) complexes on the higher-order structure of DNA by using fluorescence and atomic force microscopies. The results showed that these dinuclear Pt(II) complexes cause marked shrinkage on the conformation of genomic DNA. We also found highly cooperative inhibitory effects of these drugs on in vitro gene expression. The unique mechanism of action of these dinuclear Pt(II) complexes is discussed in terms of their bridging effect on DNA segments.

  2. At PS170 (APPLE)

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    APPLE stands for Antiproton-Proton to Pair of LEptons (an acronym of the ancestor experiment PAPLEP), the PS170 experiment setup at LEAR to study e+e-pair production in antiproton-proton annihilation by Padova-(CEN) Saclay- Torino Collaboration. It consisted of a liquid hydrogen target surrounded by several layers of proportional chambers in the vertical field of a C-magnet (this photo), a gas Cerenkov counter, wire chambers, hodoscopes, and an electromagnetic calorimeter (see photo 8302539X, 8302540X). See also photo 8301539X for the setup assembly at an early stage.

  3. EPR characterization of Mn(ii) complexes for distance determination with pulsed dipolar spectroscopy.

    Science.gov (United States)

    Keller, Katharina; Zalibera, Michal; Qi, Mian; Koch, Vanessa; Wegner, Julia; Hintz, Henrik; Godt, Adelheid; Jeschke, Gunnar; Savitsky, Anton; Yulikov, Maxim

    2016-09-14

    The four Mn(ii) complexes Mn-DOTA, Mn-TAHA, Mn-PyMTA, and Mn-NO3Py were characterized by electron paramagnetic resonance (EPR), electron-nuclear double resonance (ENDOR), and relaxation measurements, to predict their relative performance in the EPR pulse dipolar spectroscopy (PDS) experiments. High spin density localization on the metal ions was proven by ENDOR on 1H, D, 14N, and 55Mn nuclei. The transverse relaxation of the Mn(ii) complexes appears to be slow enough for PDS-based spin-spin distance determination. Rather advantageous ratios of T1/Tm were measured allowing for good relaxation induced dipolar modulation enhancement (RIDME) performance and, in general, fast shot repetitions in any PDS experiment. Relaxation properties of the Mn(ii) complexes correlate with the strengths of their zero field splitting (ZFS). Further, a comparison of Mn(ii)-DOTA and Gd(iii)-DOTA based spin labels is presented. The RIDME technique to measure nanometer-range Mn(ii)-Mn(ii) distances in biomolecules is discussed as an alternative to the well-known DEER technique that often appears challenging in cases of metal-metal distance measurements. The use of a modified kernel function that includes dipolar harmonic overtones allows model-free computation of the Mn(ii)-Mn(ii) distance distributions. Mn(ii)-Mn(ii) distances are computed from RIDME data of Mn-rulers consisting of two Mn-PyMTA complexes connected by a rodlike spacer of defined length. Level crossing effects seem to have only a weak influence on the distance distributions computed from this set of Mn(ii)-Mn(ii) RIDME data.

  4. Complexation facilitated reduction of aromatic N-oxides by aqueous Fe(II)-tiron complex: reaction kinetics and mechanisms.

    Science.gov (United States)

    Chen, Yiling; Zhang, Huichun

    2013-10-01

    Rapid reduction of carbadox (CDX), olaquindox and several other aromatic N-oxides were investigated in aqueous solution containing Fe(II) and tiron. Consistent with previous work, the 1:2 Fe(II)-tiron complex, FeL2(6-), is the dominant reactive species as its concentration linearly correlates with the observed rate constant kobs under various conditions. The N-oxides without any side chains were much less reactive, suggesting direct reduction of the N-oxides is slow. UV-vis spectra suggest FeL2(6-) likely forms 5- or 7-membered rings with CDX and olaquindox through the N and O atoms on the side chain. The formed inner-sphere complexes significantly facilitated electron transfer from FeL2(6-) to the N-oxides. Reduction products of the N-oxides were identified by HPLC/QToF-MS to be the deoxygenated analogs. QSAR analysis indicated neither the first electron transfer nor N-O bond cleavage is the rate-limiting step. Calculations of the atomic spin densities of the anionic N-oxides confirmed the extensive delocalization between the aromatic ring and the side chain, suggesting complex formation can significantly affect the reduction kinetics. Our results suggest the complexation facilitated N-oxide reduction by Fe(II)-tiron involves a free radical mechanism, and the subsequent deoxygenation might also benefit from the weak complexation of Fe(II) with the N-oxide O atom.

  5. Synthesis, characterization, DFT calculations and biological studies of Mn(II), Fe(II), Co(II) and Cd(II) complexes based on a tetradentate ONNO donor Schiff base ligand

    Science.gov (United States)

    Abdel-Rahman, Laila H.; Ismail, Nabawia M.; Ismael, Mohamed; Abu-Dief, Ahmed M.; Ahmed, Ebtehal Abdel-Hameed

    2017-04-01

    This study highlights synthesis and characterization of a tetradentate ONNO Schiff base ligand namely (1, 1‧- (pyridine-2, 3-dimethyliminomethyl) naphthalene-2, 2‧-diol) and hereafter denotes as "HNDAP″ and selected metal complexes including Mn(II), Fe(II), Co(II) and Cd(II) as a central metal. HNDAP was synthesized from 1:2 M ratio condensation of 2, 3-diaminopyridine and 2- hydroxy-1-naphthaldhyde, respectively. The stoichiometric ratios of the prepared complexes were estimated using complementary techniques such as; elemental analyses (-C, H, N), FT-IR, magnetic measurements and molar conductivity. Furthermore, their physicochemical studies were carried out using thermal TGA, DTA and kinetic-thermodynamic studies along with DFT calculations. The results of elemental analyses showed that these complexes are present in a 1:1 metal-to- ligand molar ratio. Moreover, the magnetic susceptibilities values at room temperature revealed that Mn(II), Fe(II) and Co(II) complexes are paramagnetic in nature and have an octahedral (Oh) geometry. In contrast, Cd(II) is diamagnetic and stabilizes in square planar sites. The molar conductivity measurements indicated that all complexes are nonelectrolytes in dimethyl formamide. Spectral data suggested that the ligand is as tetradentate and coordinated with Co(II) ion through two phenolic OH and two azomethine nitrogen. However, for Mn(II), Fe(II) and Cd(II) complexes, the coordination occurred through two phenolic oxygen and two azomethine nitrogen with deprotonation of OH groups. The proposed chemical structures have been validated by quantum mechanics calculations. Antimicrobial activities of both the HNDAP Schiff base ligand and its metal complexes were tested against strains of Gram (-ve) E. coli and Gram (+ve) B. subtilis and S. aureus bacteria and C. albicans, A. flavus and T. rubrum fungi. All the prepared compounds showed good results of inhibition against the selected pathogenic microorganisms. The investigated

  6. Synthesis, characterization and in vitro antimicrobial studies of Co(II), Ni(II) and Cu(II) complexes derived from macrocyclic compartmental ligand

    Science.gov (United States)

    El-Gammal, O. A.; Bekheit, M. M.; El-Brashy, S. A.

    2015-02-01

    New Co(II), Ni(II) and Cu(II) complexes derived from tetradentate macrocyclic nitrogen ligand, (1E,4E,8E,12E)-5,8,13,16-tetramethyl-1,4,9,12-tetrazacyclohexadeca-4,8,12,16-tetraene (EDHDH) have been synthesized. The complexes have been characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR and ESR (for Cu(II) complex)) mass, and magnetic as well as thermal analysis measurements. The complexes afforded the formulae: [Cu(EDHDH)Cl2]·2EtOH and [M(EDHDH)X2]·nH2O where M = Co(II) and Ni(II), X = Cl- or OH-, n = 1,0, respectively. The data revealed an octahedral arrangement with N4 tetradentate donor sites in addition to two Cl atoms occupying the other two sites. ESR spectrum of Cu2+ complex confirmed the suggested geometry with values of a α2and β2 indicating that the in-plane σ-bonding and in-plane π-bonding are appreciably covalent, and are consistent with very strong σ-in-plane bonding in the complexes. The molecular modeling is drawn and showed the bond length, bond angle, chemical reactivity, energy components (kcal/mol) and binding energy (kcal/mol) for all the title compounds using DFT method. Also, the thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. Moreover, the in vitro antibacterial studies of all compounds screened against pathogenic bacteria (two Gram +ve and two Gram -ve) to assess their inhibiting potential. The assay indicated that the inhibition potential is metal ion dependent. The ligand, EDHDH, Co(II) and Cu(II) complexes exhibited a remarkable antibacterial activity against Streptococcus Pyogenes as Gram +ve and Proteus vulgaris as Gram -ve bacterial strains. On the other hand, Ni(II) complex revealed a moderate antibacterial activity against both Gram +ve organisms and no activity against Gram -ve bacterial strain.

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

    Indian Academy of Sciences (India)

    chemsci

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

  8. Spin crossover in Fe(II) complexes with N4S2 coordination

    DEFF Research Database (Denmark)

    Arroyave, Alejandra; Lennartson, Anders; Dragulescu-Andrasi, Alina

    2016-01-01

    A systematic study of a series of Fe(II) complexes with the tetradentate N2S2-binding ligand and NCX− coligands (X = S, Se, BH3) conclusively demonstrates the occurrence of temperature-driven spin crossover (SCO), which is rarely observed for the Fe(II) ion in the N4S2 coordination environment...

  9. Enantioselectivity Measurements of Copper(II) Amino Acid Complexes Using Isothermal Titration Calorimetry

    NARCIS (Netherlands)

    Bruin, de T.J.M.; Marcelis, A.T.M.; Zuilhof, H.; Sudhölter, E.J.R.

    2000-01-01

    Enantioselectivity experiments for the binding to chiral Cu(II) complexes have been performed for several -amino acids using isothermal titration calorimetry. To a system containing nonionic micelles, Cu(II) ions, and cholesteryl glutamate as chiral selector, either the D- or L-amino acid was

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

    Indian Academy of Sciences (India)

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

  11. Structural Feature of an Hexakis-N-methylformamide Cobalt(II) Complex

    National Research Council Canada - National Science Library

    Ryo YAMAGUCHI; Daisuke YOSHIOKA; Masahiro MIKURIYA; Hiroshi SAKIYAMA

    2015-01-01

      The cobalt(II) complex [Co(NMF)6](BPh4)2 [NMF = N-methylformamide] [hexakis(N-methylformamide-κO)cobalt(II) bis(tetraphenylborate)] was prepared, and characterized by a single-crystal X-ray method...

  12. IR and ESR studies on novel Cu(II) theophyllinato complexes containing mono- or bidentate ligands

    Science.gov (United States)

    Forizs, Edit; David, L.; Cozar, O.; Chiş, V.; Damian, G.; Csibi, Jolán

    1999-05-01

    Three mixed-ligand copper(II) complexes containing theophylline and mono- or bidentate N-donor ligands (2,2'-bipyridine, 4-fluoraniline and 1,10-phenanthroline) were synthesized and characterized by elemental analysis, IR and ESR spectra. According to IR and ESR data the Cu(II) complexes exhibit a distorted tetrahedral coordination of copper by two nitrogen atoms of the monodentate or bidentate ligands and the two monodentate theophyllinate anion bonded through N(7) atom.

  13. Electronic structure of the oxygen evolving complex in photosystem II, as revealed by 55Mn Davies ENDOR studies at 2.5 K.

    Science.gov (United States)

    Jin, Lu; Smith, Paul; Noble, Christopher J; Stranger, Rob; Hanson, Graeme R; Pace, Ron J

    2014-05-07

    We report the first (55)Mn pulsed ENDOR studies on the S2 state multiline spin ½ centre of the oxygen evolving complex (OEC) in Photosystem II (PS II), at temperatures below 4.2 K. These were performed on highly active samples of spinach PS II core complexes, developed previously in our laboratories for photosystem spectroscopic use, at temperatures down to 2.5 K. Under these conditions, relaxation effects which have previously hindered observation of most of the manganese ENDOR resonances from the OEC coupled Mn cluster are suppressed. (55)Mn ENDOR hyperfine couplings ranging from ∼50 to ∼680 MHz are now seen on the S2 state multiline EPR signal. These, together with complementary high resolution X-band CW EPR measurements and detailed simulations, reveal that at least two and probably three Mn hyperfine couplings with large anisotropy are seen, indicating that three Mn(III) ions are likely present in the functional S2 state of the enzyme. This suggests a low oxidation state paradigm for the OEC (mean Mn oxidation level 3.0 in the S1 state) and unexpected Mn exchange coupling in the S2 state, with two Mn ions nearly magnetically silent. Our results rationalize a number of previous ligand ESEEM/ENDOR studies and labelled water exchange experiments on the S2 state of the photosystem, in a common picture which is closely consistent with recent photo-assembly (Kolling et al., Biophys. J. 2012, 103, 313-322) and large scale computational studies on the OEC (Gatt et al., Angew. Chem., Int. Ed. 2012, 51, 12025-12028, Kurashige et al. Nat. Chem. 2013, 5, 660-666).

  14. Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin

    OpenAIRE

    Tanabe Makoto; Simova Svetlana; Mitewa Mariana; Pantcheva Ivayla N; Ivanova Juliana; Osakada Kohtaro

    2011-01-01

    Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as poss...

  15. Structural Determination of a Transcribing RNA Polymerase II Complex

    Science.gov (United States)

    2000-05-01

    cleft between them Fig. 2. Subunit struc- tures determined pre- viously or rebuilt here A B C fitted to the experi- u197-210 mental pot II electron...and 3 mM DTT). Crystals were cooled to 4*C mental zinc peak (Fig. 2B). The COOH-terminal re- Res. 21, 113 (1993). overnight and maintained at that...detected with the Infrared Space Obser- stituto de Estructura de Ia Materia, Departamento Fisica Molecular, Serrano 121, 28006 Madrid, Spain. vatory

  16. Synthesis and Characterization of Some New Cu(II, Ni(II and Zn(II Complexes with Salicylidene Thiosemicarbazones: Antibacterial, Antifungal and in Vitro Antileukemia Activity

    Directory of Open Access Journals (Sweden)

    Tudor Rosu

    2013-07-01

    Full Text Available Thirty two new Cu(II, Ni(II and Zn(II complexes (1–32 with salicylidene thiosemicarbazones (H2L1–H2L10 were synthesized. Salicylidene thiosemicarbazones, of general formula (XN-NH-C(S-NH(Y, were prepared through the condensation reaction of 2-hydroxybenzaldehyde and its derivatives (X with thiosemicarbazide or 4-phenylthiosemicarbazide (Y = H, C6H5. The characterization of the new formed compounds was done by 1H-NMR, 13C-NMR, IR spectroscopy, elemental analysis, magnetochemical, thermoanalytical and molar conductance measurements. In addition, the structure of the complex 5 has been determined by X-ray diffraction method. All ligands and metal complexes were tested as inhibitors of human leukemia (HL-60 cells growth and antibacterial and antifungal activities.

  17. Intercalation of a Zn(II) complex containing ciprofloxacin drug between DNA base pairs.

    Science.gov (United States)

    Shahabadi, Nahid; Asadian, Ali Ashraf; Mahdavi, Mryam

    2017-11-02

    In this study, an attempt has been made to study the interaction of a Zn(II) complex containing an antibiotic drug, ciprofloxacin, with calf thymus DNA using spectroscopic methods. It was found that Zn(II) complex could bind with DNA via intercalation mode as evidenced by: hyperchromism in UV-Vis spectrum; these spectral characteristics suggest that the Zn(II) complex interacts with DNA most likely through a mode that involves a stacking interaction between the aromatic chromophore and the base pairs of DNA. DNA binding constant (K b = 1.4 × 10 4 M -1 ) from spectrophotometric studies of the interaction of Zn(II) complex with DNA is comparable to those of some DNA intercalative polypyridyl Ru(II) complexes 1.0 -4.8 × 10 4 M -1 . CD study showed stabilization of the right-handed B form of DNA in the presence of Zn(II) complex as observed for the classical intercalator methylene blue. Thermodynamic parameters (ΔH DNA-MB, indicating that it binds to DNA in strong competition with MB for the intercalation.

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

    Science.gov (United States)

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

    2017-10-01

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

  19. Investigation of detergent effects on the solution structure of spinach Light Harvesting Complex II

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Mateus B; Smolensky, Dmitriy; Heller, William T; O' Neill, Hugh, E-mail: hellerwt@ornl.gov, E-mail: oneillhm@ornl.gov [Center for Structural Molecular Biology, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2010-11-01

    The properties of spinach light harvesting complex II (LHC II), stabilized in the detergents Triton X-100 (TX100) and n-Octyl-{beta}-D-Glucoside (BOG), were investigated by small-angle neutron scattering (SANS). The LHC II-BOG scattering curve overlaid well with the theoretical scattering curve generated from the crystal structure of LHC II indicating that the protein preparation was in its native functional state. On the other hand, the simulated LHC II curve deviated significantly from the LHC II-TX100 experimental data. Analysis by circular dichroism spectroscopy supported the SANS analysis and showed that LHC II-TX100 is inactivated. This investigation has implications for extracting and stabilizing photosynthetic membrane proteins for the development of biohybrid photoconversion devices.

  20. Investigation of Detergent Effects on the Solution Structure of Spinach Light Harvesting Complex II

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Mateus B [ORNL; Smolensky, Dmitriy [ORNL; Heller, William T [ORNL; O' Neill, Hugh Michael [ORNL

    2010-01-01

    The properties of spinach light harvesting complex II (LHC II), stabilized in the detergents Triton X-100 (TX100) and n-Octyl-{beta}-D-Glucoside (BOG), were investigated by small-angle neutron scattering (SANS). The LHC II-BOG scattering curve overlaid well with the theoretical scattering curve generated from the crystal structure of LHC II indicating that the protein preparation was in its native functional state. On the other hand, the simulated LHC II curve deviated significantly from the LHC II-TX100 experimental data. Analysis by circular dichroism spectroscopy supported the SANS analysis and showed that LHC II-TX100 is inactivated. This investigation has implications for extracting and stabilizing photosynthetic membrane proteins for the development of biohybrid photoconversion devices.

  1. Determination of mixed stability constants of lead(II/uranyl(II-NTA-cysteine complexes by paper electrophoresis

    Directory of Open Access Journals (Sweden)

    Brij Bhushan Tewari

    2005-12-01

    Full Text Available A method involving the use of paper ionophoresis is described for the study of equilibria in mixed – ligand complex systems in solution. The technique is based on the movement of a spot of metal ion under an electric field with the complexants added to the background electrolyte at pH 8.5. The stability constants of the complexes Pb(II – nitrilotriacetate – cysteine and UO2(II – nitrilotriacetate – cysteine are found to be 5.35 plus or minus 0.02 and 6.27 plus or minus 0.07 (logarithm of stability constant values at ionic strength 0.1 M and a temperature of 35 0C.

  2. Synthesis, magnetic, spectral, and antimicrobial studies of Cu(II), Ni(II) Co(II), Fe(III), and UO 2(II) complexes of a new Schiff base hydrazone derived from 7-chloro-4-hydrazinoquinoline

    Science.gov (United States)

    El-Behery, Mostafa; El-Twigry, Haifaa

    2007-01-01

    A new hydrazone ligand, HL, was prepared by the reaction of 7-chloro-4-hydrazinoquinoline with o-hydroxybenzaldehyde. The ligand behaves as monoprotic bidentate. This was accounted for as the ligand contains a phenolic group and its hydrogen atom is reluctant to be replaced by a metal ion. The ligand reacted with Cu(II), Ni(II), Co(II), Fe(III), and UO 2(II) ions to yield mononuclear complexes. In the case of Fe(III) ion two complexes, mono- and binuclear complexes, were obtained in the absence and presence of LiOH, respectively. Also, mixed ligand complexes were obtained from the reaction of the metal cations Cu(II), Ni(II) and Fe(III) with the ligand (HL) and 8-hydroxyquinoline (8-OHqu) in the presence of LiOH, in the molar ratio 1:1:1:1. It is clear that 8-OHqu behaves as monoprotic bidentate ligand in such mixed ligand complexes. The ligand, HL, and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass, and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square-planar geometry, while Ni(II) mixed complex has also formed a tetrahedral configuration and UO 2(II) complex which formed a favorable pentagonal biprymidial geometry. Magnetic moment of the binuclear Fe(III) complex is quite low compared to calculated value for two iron ions complex and thus shows antiferromagnetic interactions between the two adjacent ferric ions. The HL and metal complexes were tested against one stain Gram positive bacteria ( Staphylococcus aureus), Gram negative bacteria ( Escherichia coli), and fungi ( Candida albicans). The tested compounds exhibited higher antibacterial acivities.

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

    Indian Academy of Sciences (India)

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

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

    Indian Academy of Sciences (India)

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

  5. Mn (II) complexes with bipyridine, phenanthroline and benzoic acid ...

    Indian Academy of Sciences (India)

    The presence of two different types and the number of chelating NN-donor neutral ligands allowed for analysis of their effects on the catalase and biological activities. It was observed that the presence and number of phen ligands improved the activity more than the bipy ligand. Complexes 1 and 2, which contain more basic ...

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

    Indian Academy of Sciences (India)

    ARC

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

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

    Indian Academy of Sciences (India)

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

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

    Indian Academy of Sciences (India)

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

  9. Chalcogenated Schiff bases: Complexation with palladium(II) and ...

    Indian Academy of Sciences (India)

    The Pd–complexes (3–4) of L6–L7 were explored for Suzuki–Miyaura coupling and found promising as 0.006 mol % of 3 is sufficient to obtain good conversion with TON up to 1.58 × 104. Keywords. Chalcogenated Schiff base; palladium; Suzuki coupling; crystal structure. 1. Introduction. Schiff bases and related compounds ...

  10. Beyond iPS!

    Directory of Open Access Journals (Sweden)

    Editorial

    2012-01-01

    Full Text Available It’s undoubtedly a jubilant moment for scientists and clinicians working in the stem cell arena as Prof. Gurdon and Prof. Shinya Yamanaka have been chosen for the Nobel Prize in Physiology & Medicine this year. The mystery of cell biology is something unfathomable and probably the work of this duo as well as the other scientists, who have put their hands on in- vitro de-differentiation have opened our eyes to a new window or a new paradigm in cell biology. The iPS invention has brought a lot of hope in terms of potential direct benefits to treat several diseases, which have no definite options at the moment. But, we envisage that several spin-offs could come out of this invention and one very significant spin-off finding recently witnessed is the finding by Prof. Masaharu Seno and his team of researchers at the Okayama University, Japan (Chen L, et al. 2012, PLoS ONE 7(4:e33544.doi:10.1371/journal.pone.0033544. According to Prof. Seno, mouse iPS cells (miPS when cultured in the conditioned medium derived from cancer cell lines, differentiate into cancer stem cells (CSCs. While differentiating into CSCs, they do retain the potential to develop endothelial progenitor cells. Several questions arise here: 1.Are these miPS derived CSCs really pluripotent, even if the terminal differentiation destined to specific phenotypes? 2.Shouldn’t the Cancer Stem Cells be termed as cancer progenitor cells, as till date they are considered to be producing only cancer cells but not pluripotent to yield other types of normal tissues? The spin-offs could be infinite as the process of differentiation and de-differentiation happening due to trillions of signals and pathways, most still remaining not-so-well understood. A special mention should be made to Prof. Shinya Yamanaka as he has several sterling qualities to be a role-model for budding scientists. Apart from his passion for science, which made him shift his career from orthopedics to a cell biologist, his

  11. Cobalt (II, nickel (II, copper (II and zinc (II complexes of 1-(phenyl(phenylamino methylpyrrolidine-2,5-dione and 2-((phenylaminomethyl isoindoline-1,3-dione and their biological activity

    Directory of Open Access Journals (Sweden)

    D. Tamil Vendan

    2010-12-01

    Full Text Available The new Mannich bases 1-(phenyl(phenylaminomethylpyrrolidine-2,5-dione (SBA was synthesized from the condensation of succinimide, benzaldehyde and aniline. 2-((phenylaminomethylisoindoline-1,3-dione (PFA was derived from pthalimide, formaldehyde and aniline. The general formula of the Co (II, Ni (II, Cu (II and Zn (II chloro complexes, ML2X2 are reported. The ligands and the complexes have been characterized by various physical-chemical techniques such as elemental analysis, molar conductance, magnetic susceptibility measurements, infrared and electronic spectra. The spectral analysis to ascertain mode of bonding and overall geometry of the complexes revealed octahedral geometries.

  12. Cu(II), Ni(II), and Zn(II) Complexes of Salan-Type Ligand Containing Ester Groups: Synthesis, Characterization, Electrochemical Properties, and In Vitro Biological Activities

    OpenAIRE

    Jeslin Kanaga Inba, P.; B. Annaraj; Thalamuthu, S.; Neelakantan, M.A.

    2013-01-01

    A salen ligand on reduction and N-alkylation affords a novel [N2O2] chelating ligand containing ester groups [L = diethyl-2,2′-(propane-1,3-diylbis((2-hydroxy-3-methoxy benzyl)azanediyl))diacetate]. The purity of the ligand was confirmed by NMR and HPLC chromatograms. Its Cu(II), Ni(II), and Zn(II) complexes were synthesized and characterized by a combination of elemental analysis, IR, NMR, UV-Vis, and mass spectral data, and thermogravimetric analysis (TG/DTA). The magnetic moments, UV-Vis, ...

  13. Cu(II), Ni(II), and Zn(II) Complexes of Salan-Type Ligand Containing Ester Groups: Synthesis, Characterization, Electrochemical Properties, and In Vitro Biological Activities.

    Science.gov (United States)

    Jeslin Kanaga Inba, P; Annaraj, B; Thalamuthu, S; Neelakantan, M A

    2013-01-01

    A salen ligand on reduction and N-alkylation affords a novel [N2O2] chelating ligand containing ester groups [L = diethyl-2,2'-(propane-1,3-diylbis((2-hydroxy-3-methoxy benzyl)azanediyl))diacetate]. The purity of the ligand was confirmed by NMR and HPLC chromatograms. Its Cu(II), Ni(II), and Zn(II) complexes were synthesized and characterized by a combination of elemental analysis, IR, NMR, UV-Vis, and mass spectral data, and thermogravimetric analysis (TG/DTA). The magnetic moments, UV-Vis, and EPR spectral studies support square planar geometry around the Cu(II) and Ni(II) ions. A tetrahedral geometry is observed in four-coordinate zinc with bulky N-alkylated salan ligand. The redox properties of the copper complex were examined in DMSO by cyclic voltammetry. The voltammograms show quasireversible process. The interaction of metal complexes with CT DNA was investigated by UV-Vis absorption titration, ethidium bromide displacement assay, cyclic voltammetry methods, and agarose gel electrophoresis. The apparent binding constant values suggest moderate intercalative binding modes between the complexes and DNA. The in vitro antioxidant and antimicrobial potentials of the synthesized compounds were also determined.

  14. Redox reactions of Cu(II)-amine complexes in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kumbhar, A.G.; Kishore, Kamal E-mail: kakish@magnum.barc.errnet.in

    2003-03-01

    A number of amines can be employed for all volatile treatment (AVT) of steam generator (SG) systems of nuclear power reactors. These amines form complexes with Cu{sup 2+} and Ni{sup 2+} ions which come into water due to corrosion. The redox reactions of a number of Cu(II)-AVT amine complexes and the stability of the transient species formed have been studied by pulse radiolysis technique. Rate constants for the reaction of e{sub aq}{sup -} with a number of Cu(II)-amine complexes have been determined by following the decay of e{sub aq}{sup -} absorption. Stability of Cu(I)-amine complexes was studied by following the kinetics of the bleaching signal formed at the {lambda}{sub max} of the Cu(II) amine complex. Except for Cu(I)-triethanolamine complex all other Cu(I)-amine complexes were found to be stable. One-electron oxidation of Cu(II) amine complexes was studied using azidyl radicals for the oxidation reaction as OH radicals react with the alcohol groups present in the amines used in this study. Cu(III)-amine complexes were found to be unstable and decayed by second-order kinetics.

  15. Structural, spectroscopic and quantum chemical studies of acetyl hydrazone oxime and its palladium(II) and platinum(II) complexes

    Science.gov (United States)

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T.; Buyukgungor, Orhan

    2015-09-01

    Acetyl hydrazone oxime, [(1E,2E)-2-(hydroxyimino)-1-phenylethylidene]acetohydrazone (hipeahH2) and its palladium(II) and platinum(II) complexes, [M(hipeahH)2] (M = PdII and PtII), have been synthesized and characterized by elemental analysis, UV-vis IR, NMR and LC-MS techniques. X-ray diffraction analysis of [Pd(hipeahH)2] shows that the two hipeahH2 ligands are not equal; one of the ligands loses the hydrazone proton, while the other one loses the oxime proton, resulting in a different coordination behavior to form five- and six-membered chelate rings. The molecular geometries from X-ray experiments in the ground state were compared using the density functional theory (DFT) with the B3LYP method combined with the 6-311++G(d,p) basis set for the ligand and the LanL2DZ basis set for the complexes. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, NMR and UV-vis spectrometry. In addition, the isomer studies of ligand and its complexes were made by DFT.

  16. Effect of Schiff base Cu(II) complexes on signaling pathways in HT-29 cells.

    Science.gov (United States)

    Koňariková, Katarína; Perdikaris, Georgios A; Gbelcova, Helena; Andrezálová, Lucia; Švéda, Martin; Ruml, Tomáš; Laubertová, Lucia; Žitňanová, Ingrid

    2016-11-01

    Schiff base copper (II) complexes are known for their anticancer, antifungal, antiviral and anti‑inflammatory activities. The aim of the current study was to investigate biological effects of Schiff base Cu (II) complexes (0.001‑100 µmol/l)‑[Cu2(sal‑D, L‑glu)2(isoquinoline)2]·2C2H5OH (1), [Cu(sal‑5‑met‑L‑glu)(H2O)].H2O (2), [Cu(ethanol)2(imidazole)4][Cu2(sal‑D, L-glu)2(imidazole)2] (3), [Cu(sal‑D,L‑glu)(2‑methylimidazole)] (4) on the human colon carcinoma cells HT‑29, the mouse noncancerous cell line NIH‑3T3 and the human noncancerous fibroblast cell line VH10. The results suggested that Cu (II) complexes exhibit cytotoxic effects against the HT‑29 cell line, while complexes 3 and 4 were the most effective. Subsequent to 72 h of incubation, apoptosis was observed in the HT‑29 cells induced by Cu (II) complexes 1 (0.1, 1, 10 and 50 µmol/l), 2 (1, 10, 50 and 100 µmol/l), 3 (0.01, 1, 10 and 50 µmol/l) and 4 (0.01, 0.1, 1 and 10 µmol/l). The apoptotic pathways activated by the Cu (II) complexes were identified. The results indicated that complexes 2, 3 and 4 were able to induce the mitochondria‑dependent pathway of apoptosis in HT‑29 cells, while complex 1 was obsered to activate the extrinsic pathway of apoptosis. The levels of the anti‑apoptotic protein Bcl‑2 were reduced and those of the pro‑apoptotic protein Bax increased following treatment with complexes 2, 3 and 4. Complex 1 had no effect on Bax protein expression. Complexes 2 and 3 induced elevation of cytochrome c (cyt c), while complex 4 induced a time‑dependent elevation of cyt c levels. No cyt c was detected in HT‑29 cells exposed to complex 1, suggesting that Cu (II) complexes activated the extrinsic pathway of apoptosis. The results from the current study in addition to previous studies suggest that Schiff base Cu (II) complexes have potential as novel anticancer drugs.

  17. Synthesis and Spectral Investigations of Manganese(II, Cobalt(II, Nickel(II, Copper(II and Zinc(II Complexes of New Polydentate Ligands Containing a 1,8-Naphthyridine Moiety

    Directory of Open Access Journals (Sweden)

    Sunkari Jyothi

    2006-12-01

    Full Text Available 2-(o-Hydroxyphenyl-1,8-naphthyridine (HN, 2-(4-hydroxy-6-methylpyran-2-one-3-yl-1,8-naphthyridine (HMPN and 2-(benzimidazol-2-yl-1,8-naphthyridine(BN react with acetates of Mn(II, Co(II, Ni(II, Cu(II and Zn(II to yield metal ioncomplexes of definite composition. These compounds were characterized by elementalanalyses, molar conductivity, magnetic susceptibility measurements, thermal studies, IR,UV-visible, NMR and mass spectral investigations. The complexes are found to have theformulae [M(HN2(H2O2], [M(HMPN2(H2O2] and [M(BN2(OAc2], respectively.

  18. Copper II - polar amino acid complexes: toxicity to bacteria and larvae of Aedes aegypti

    Directory of Open Access Journals (Sweden)

    THIAGO A.D. RODRIGUES

    Full Text Available ABSTRACT Control strategies using insecticides are sometimes ineffective due to the resistance of the insect vectors.In this scenario new products must be proposed for the control of insect vectors.The complexes L-aspartate Cu (II and L-glutamate-Cu (II complexes were synthesized and characterized by elemental analysis, visible ultraviolet, infrared spectroscopy and potentiometric titration. The toxicity of these complexes was analyzed in Aedes aegypti (Diptera: Culicidae larvae and Gram-negative and Gram-positive bacteria. The interaction between the ligands and the amino acid balance and the distribution of the species as a function of pH were discussed. The lethal concentration median (LC50 for Ae. aegypti larvae were: L-glutamic acid-Cu (II - 53.401 mg L-1 and L-aspartate-Cu (II - 108.647 mg L-1. The minimum inhibitory concentration (MIC required for Staphylococcus aureus and Escherichia coli was: L-glutamate-Cu (II 500-2000 mg L-1 and L-aspartate-Cu (II 1000-2000 mg L-1. The concentrations demonstrated toxicity that evidence the potential of the complexes as bactericide and insecticide. Metal complexes formed by amino acids and transition metals are advantageous because of low environmental toxicity, biodegradability and low production cost.

  19. Synthesis, spectroscopic, molecular structure, antioxidant, antimicrobial and antitumor behavior of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of O2N type tridentate chromone-2-carboxaldehyde Schiff's base ligand

    Science.gov (United States)

    Ammar, Reda A.; Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Al-Bedair, Lamia A.

    2017-08-01

    Tridentate Schiff's base (HL) ligand was synthesized via condensation of salicylaldehyde and 3-hydroxypyridin-2-yliminomethyl-4H-chromen-4-one and their corresponding Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. The isolated solid complexes were characterized by elemental analyses, molar conductance, spectral (IR, UV-Vis, 1H NMR), magnetic moment, EPR, and thermal measurements. The IR spectra showed that HL was coordinated to the metal ions in tridentate manner with O2N donor sites of the azomethine N, deprotonated phenolic-OH and carbonyl-O. The activation of thermodynamic parameters are calculated using Coast-Redfern and Horowitz-Metzger (HM). The octahedral geometry of the complexes is confirmed using DFT method from DMOL3 calculations, UV-Vis and magnetic moment measurements, ESR and ligand field parameters. Antioxidant activities have also been performed for all the compounds. The investigated ligand and metal complexes were screened for their in-vitro antimicrobial activities against different types of fungal and bacterial strains. The resulting data assert on the inspected compounds as a highly promising bactericides and fungicides. The antitumor activities of all inspected compounds were evaluated towards human liver Carcinoma (HepG2) cell line.

  20. Indirect spectrophotometric determination of thiocyanate by extraction as bisthiocyanatobisquinolinemercury(II) complex and its ligand substitution reaction with dithizone.

    Science.gov (United States)

    Einaga, H; Ishii, H; Iwasaki, I

    1973-10-01

    Thiocyanate forms with mercury(II) in the presence of quinoline a mixed-ligand mercury(II) complex, bisthiocyanatobisquinolinemercury(II), and is extracted into chloroform. This mixed-ligand complex is treated with dithizone and forms the bisdithizonatomercury(II) complex. Maximum and constant absorbance of the dithizone complex is obtained when thiocyanate is extracted at pH 5.1-6.5, and Beer's law is obeyed at 498 nm, where the difference in absorbance between the dithizone complex and dithizone is largest. Chloride, bromide, iodide, cyanide and large amounts of ammonium and copper(II) ions interfere.

  1. Two different zinc (II)-aqua complexes held up by a metal-oxide ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 120; Issue 1. Two different zinc(II)-aqua complexes held up by a metal-oxide based support: Synthesis, crystal ... Keywords. Inorganic-organic hybrid material; polyoxometalate supported zinc complexes; crystal structure; supramolecular interactions; catalytic activity.

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

    Indian Academy of Sciences (India)

    Unknown

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

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

    Indian Academy of Sciences (India)

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

  4. Catalytic dioxygen activation by Co(II) complexes employing a coordinatively versatile ligand scaffold.

    Science.gov (United States)

    Sharma, Savita K; May, Philip S; Jones, Matthew B; Lense, Sheri; Hardcastle, Kenneth I; MacBeth, Cora E

    2011-02-14

    The ligand bis(2-isobutyrylamidophenyl)amine has been prepared and used to stabilize both mononuclear and dinuclear cobalt(II) complexes. The nuclearity of the cobalt product is regulated by the deprotonation state of the ligand. Both complexes catalytically oxidize triphenylphosphine to triphenylphosphine oxide in the presence of O(2).

  5. DNA incision evaluation, binding investigation and biocidal screening of Cu(II), Ni(II) and Co(II) complexes with isoxazole Schiff bases.

    Science.gov (United States)

    Ganji, Nirmala; Chityala, Vijay Kumar; Marri, Pradeep Kumar; Aveli, Rambabu; Narendrula, Vamsikrishna; Daravath, Sreenu; Shivaraj

    2017-10-01

    Two new series of binary metal complexes [M(L 1 ) 2 ] and [M(L 2 ) 2 ] where, M=Cu(II), Ni(II) & Co(II) and L 1 =4-((3,4-dimethylisoxazol-5-ylimino)methyl)benzene-1,3-diol; L 2 =2-((3,4-dimethylisoxazol-5-ylimino)methyl)-5-methoxyphenol were synthesized and characterized by elemental analysis, 1 H NMR, 13 C NMR, FT-IR, ESI mass, UV-Visible, magnetic moment, ESR, SEM and powder XRD studies. Based on these results, a square planar geometry is assigned for all the metal complexes where the Schiff base acts as uninegatively charged bidentate chelating agent via the hydroxyl oxygen and azomethine nitrogen atoms. DNA binding studies of all the complexes with calf thymus DNA have been comprehensively investigated using electronic absorption spectroscopy, fluorescence quenching and viscosity studies. The oxidative and photo cleavage affinity of metal complexes towards supercoiled pBR322 DNA has been ascertained by agarose gel electrophoresis assay. From the results, it is observed that all the metal complexes bind effectively to CT-DNA via an intercalative mode of binding and also cleave pBR322 DNA in a promising manner. Further the Cu(II) complexes have shown better binding and cleavage properties towards DNA. The antimicrobial activities of the Schiff bases and their metal complexes were studied on bacterial and fungal strains and the results denoted that the complexes are more potent than their Schiff base ligands. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Dinuclear ruthenium(II) and/or osmium(II) complexes of bipyridyl ...

    Indian Academy of Sciences (India)

    Administrator

    2Ru-. BL1/BL2-Os(bpy)2]4+ have been synthesized. For the synthesis of heterodinuclear complexes a new strategy has been adopted, which eliminates the possibility of the presence of homodinuclear complexes as impurity. Mononuclear model ...

  7. Synthesis, Spectral Characterization and Antioxidant Activity of Tin(II-Morin Complex

    Directory of Open Access Journals (Sweden)

    Shahabuddin Memon

    2012-12-01

    Full Text Available The study focuses on the interaction between morin and Tin(II and the resulting complex was characterized through various analytical techniques by comparing it with morin. The complexation was confirmed at first by UV-Vis study, which shows that addition of Tin(II to morin may produce bathochromic shifts indicative of complex formation. IR spectral studies indicated that carbonyl has involved in coordination with Tin(II. Moreover, 1H-NMR studies validated that in conjunction with carbonyl, 3-OH of morin is more appropriate to be involved in complexation by replacement of its proton. Scavenging activities of morin and its Tin(II complex on DPPH• radical showed the inhibitory rates of 65% and 49%, respectively. In addition, the reducing capacity of morin was outstanding at 0.5 and 2.0 mg/ml concentrations relative to Tin(II complex. Overall, the study potentially shows the strong impact in order to design the anticancer drugs jointly from its cytotoxic potential and antioxidant activities, thereby selectively targeting the cancerous cells in result increasing their therapeutic index as well as extra advantages over other anticancer drugs.

  8. High-spin binuclear Co(II complexes with a pendant octaazamaclocycle and carboxylates

    Directory of Open Access Journals (Sweden)

    G. VUCKOVIC

    2007-12-01

    Full Text Available Three new binuclear Co(II mixed-ligand complexes with N,N′,N′′,N′′′-tetrakis(2-pyridylmethyl-1,4,8,11-tetraazacyclotetradecane (tpmc and mono- or dicarboxylate ligands were prepared and some of their physical properties were determined. The general formulas: [Co2(HCOO2tpmc](ClO42·4H2O, [Co2(CH3COO2tpmc](ClO42 and [Co2(tphttpmc](ClO42·4H2O (tphtH2 = terephthalic acid were proposed on the basis of elemental analyses (C,H,N and molar conductivity. UV/Vis absorption and IR spectra, magnetic and CV measurements were used to study their geometries and properties. For the monocarboxylate complexes, an exo coordination of Co(II with four nitrogens from tpmc and bis-bidentate bonded HCOO-/CH3COO- in the trans position is assumed. Tpmc adopts the chair conformation. For the dicarboxylate complex, it is supposed that a terephthalate dianion, as well as methylene chains from cyclam bridged two Co(II atoms, while tpmc is in the boat conformation. The complexes were stable against chemical and electrochemical oxidation of Co(II to Co(III. The data are compared with those for the previously published Cu(II complexes containing the corresponding ligands and mutual similarities or differences were considered. Finally, some antibacterial activity of the complexes was found.

  9. Synthesis, structural and biochemical activity studies of a new hexadentate Schiff base ligand and its Cu(II), Ni(II), and Co(II) complexes

    Science.gov (United States)

    Ekmekcioglu, Pinar; Karabocek, Nevin; Karabocek, Serdar; Emirik, Mustafa

    2015-11-01

    A new Schiff base ligand (H2L) and its metal complexes have been prepared and characterized by elemental analysis, magnetic moment and spectral studies. The comparative in-vitro antimicrobial activities against various pathogens with reference to known antibiotics activity under the standard control of different concentrations revealed that the metal complexes (6-8) showed enhanced antimicrobial activities in general as compared to free ligand. As an exception, the free ligand showed better activity against Trichoderma. The antifungal activity experiments were performed in triplicate. The order of biochemical activity for metal complexes were observed as in the following. CuL > CoL > NiL, which is exactly same as the order of stability constants of these complexes. Additionally, we performed DFT and TD-DFT calculation for free ligand and Cu(II) complex to support the experimental data. The geometries of the Cu(II) complex have been optimized using the B3LYP level of theory. The theoretical calculations confirm that the copper (II) center exhibits a distorted square pyramidal geometry which is favored by experimental results.

  10. Which is the Stronger Nucleophile, Platinum or Nitrogen in Rollover Cycloplatinated(II) Complexes?

    Science.gov (United States)

    Niroomand Hosseini, Fatemeh; Nabavizadeh, S Masoud; Abu-Omar, Mahdi M

    2017-12-04

    The rollover cyclometalated platinum(II) complexes [PtMe(2,X'-bpy-H)(PPh3)], (X = 2, 1a; X = 3, 1b; and X = 4, 1c) containing two potential nucleophilic centers have been investigated to elucidate which center is the stronger nucleophile toward methyl iodide. On the basis of DFT calculations, complexes 1b and 1c are predicted reacting with MeI through the free nitrogen donor to form N-methylated platinum(II) complexes, while complex 1a reacts through oxidative addition on platinum to give a platinum(IV) complex, which is in agreement with experimental findings. The reasons for this difference in selectivity for complexes 1a-1c are discussed based on the energy barrier needed for N-methylation versus oxidative addition reactions.

  11. Spectroscopic, electrochemical, magnetic and structural investigations of dimanganese-(II/II) and mixed-valence-(II/III)-tetraiminodiphenolate complexes

    OpenAIRE

    Rocha, Julio C. da; Poneti, Giordano; Ferreira,Janaina G.; Ribeiro, Ronny R.; Nunes, Fábio S.

    2014-01-01

    Synthesis, spectroscopic [electron paramagnetic resonance (EPR), UV-Vis and Fourier transform infrared spectroscopy (FTIR)], magnetic and spectroeletrochemical properties of [MnII2(tidf)(OAc)(ClO4)(MeOH)] (tidf = a Robson type macrocyclic ligand obtained through condensation of 2,6-diformyl-4-methylphenol and 1,3-diaminopropane) are reported. Compound [MnII2(tidf)(OAc)(ClO4)(MeOH)] shows a weak antiferromagnetic behavior with exchange coupling constant J = -1.59(1) cm-1. UV-Vis and EPR spectr...

  12. Two uranyl complexes with pyromellitic acid. A heterometallic complex with U=O-Cu{sup II} interaction

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Lingling; Cai, Yige; Li, Xiang; Zhang, Ronglan; Zhao, Jianshe [College of Chemistry and Materials, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi' an (China); Liu, Chiyang [Department of Geology, Northwest University, Xi' an (China); Weng, Ng Seik [Department of Chemistry, University of Malaya, Kuala Lumpur (Malaysia)

    2015-08-15

    Two uranyl complexes based on pyromellitic acid were hydrothermally synthesized, and their X-ray single-crystal diffraction structures were determined. Complex [UO{sub 2}(Hbtec)]{sup -}(Himd){sup +}.H{sub 2}O (1) (H{sub 4}btec = pyromellitic acid, imd = imidazole), is an ionic complex, which shows a typical (4, 4) topological structure in the space. A heterometallic complex, UO{sub 2}Cu(btec)(phen) (2) (phen = 1,10-phenanthroline) results from the reaction of uranyl nitrate and copper(II) bromide with pyromellitic acid. The structure of complex 2 revealed that the chains of UO{sub 7} and CuO{sub 3}N{sub 2} units were connected to each other through the carboxyl groups and U=O-Cu interactions to create a two-dimensional framework. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Synthesis, spectral characterization and biological evaluation of copper(II) and nickel(II) complexes with thiosemicarbazones derived from a bidentate Schiff base

    Science.gov (United States)

    Chandra, Sulekh; Bargujar, Savita; Nirwal, Rita; Yadav, Neesha

    2013-04-01

    Complexes of copper(II) and nickel(II) of general composition M(L)2X2, have been synthesized with the ligand 1-Tetralone thiosemicarbazone (where L = 1-Tetralone thiosemicarbazone and X=Cl,1/2SO42-). The molar conductance of the complexes in fresh solution of DMSO lies in the range of 10-20 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. Thus, the complexes may be formulated as [M(L2)X2]. Ligand was characterized by mass, NMR, IR and single crystallographic studies. All the complexes were characterized by elemental analyses, magnetic moments, IR, electronic and EPR spectral studies. The IR spectral data of ligand indicated the involvement of sulfur and azomethine nitrogen in coordination to the central metal ion. The copper(II) and nickel(II) complexes were found to have magnetic moments1.93-1.96 BM and 2.91-2.94 BM corresponding to one and two unpaired electrons respectively. On the basis of molar conductance, EPR, electronic and infrared spectral studies, a tetragonal geometry has been assigned for Cu(II) chloride complex and trigonal bipyramidal to Cu(II) sulfate complex but an octahedral geometry for Ni(II) complexes. Newly synthesized ligand and its Cu(II) and Ni(II) complexes have also been screened against different bacterial and fungal species.

  14. Synthesis, Characterization and DNA-Binding Properties of The Novel Mononuclear Zn(II, Cd(II, and Mn(II Complexes with Pantoprazole.

    Directory of Open Access Journals (Sweden)

    Wessam N. El-Sayed

    2016-04-01

    Full Text Available A   novel   mononuclear   Mn(II,   Zn(II   and   Cd(II   complexes of pantoprazole   (PA   was synthesized  and characterized  by elemental analysis,  molar conductivity,  magnetic susceptibility   measurements,   IR,  UV-visible  spectral  studies,  and  thermal  analysis.  The electronic spectra along with magnetic data suggest octahedral geometry for Mn(II, Zn(II and Cd(II complexes.  PA acts as an anionic bi-dentate ligand being coordinated by (S=O oxygen and benzimdazolyl nitrogen atoms. The interaction of the complexes with calf thymus DNA (CT-DNA was monitored by blue shift and hyperchromism in the UV-vis spectra. The observed  intrinsic  binding  constants  together  with  structural  analysis  of  the  complexes indicate  the groove  binding. The binding constants were determined at 303°K, 308°K and 313°K.  A thermodynamic analysis showed that the reaction is spontaneous with ΔG being negative. The enthalpy ΔH and the entropy ΔS of reactions were all determined.

  15. EPR study of complex formation between copper (II) ions and sympathomimetic amines in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Preoteasa, E.A. [Inst. of Atomic Physics, IFIN, Bucharest (Romania); Duliu, O.G.; Grecu, V.V. [Bucharest, Univ. (Romania). Dept. of Atomic and Nuclear Physics

    1997-07-01

    The complex formation between sympathomimetic amines (SA): adrenaline (AD), noradrenaline (NA), dopamine (DA), ephedrine (ED) and p-tyramine (pTA), and Cu(II) ion in aqueous solution has been studied by X-band EPR at room temperature. Excepting pTA, all investigated SA yielded two types of complexes in different pH domains. All complexes consistent with a ligand fields having a distorted octahedral symmetry, i.e., hexacoordination of Cu(II). The covalence coefficient calculated from the isotropic g and A values has shown strong ionic sigma-type ligand bonds. A structural model with the Cu(II) ion bound by four catecholic O(hydroxy) atoms for the low pH complexes of AD, NA and DA is proposed. For the high pH complexes of the former compounds as well as for both Ed complexes, the authors suppose Cu(II) bound by two N (amino) and two O (hydroxy) atoms. The spectra are consistent to water binding on the longitudinal octahedron axis in all compounds excepting the high pH complex of Ed, where OH2- ions are bound. Possible implications for the SA-cell receptors interactions are discussed.

  16. Light harvesting and directional energy transfer in long-lived homo- and heterotrimetallic complexes of Fe(II), Ru(II), and Os(II).

    Science.gov (United States)

    Maity, Dinesh; Bhaumik, Chanchal; Mardanya, Sourav; Karmakar, Srikanta; Baitalik, Sujoy

    2014-10-06

    A new family of trimetallic complexes of the form [(bpy)2 M(phen-Hbzim-tpy)M'(tpy-Hbzim-phen)M(bpy)2](6+) (M=Ru(II), Os; M'=Fe(II), Ru(II), Os; bpy=2,2'-bipyridine) derived from heteroditopic phenanthroline-terpyridine bridge 2-{4-[2,6-di(pyridin-2-yl) pyridine-4-yl]phenyl}-1H-imidazole[4,5-f][1,10]phenanthroline (phen-Hbzim-tpy) were prepared and fully characterized. Zn(2+) was used to prepare mixed-metal trimetallic complexes in situ by coordinating with the free tpy site of the monometallic precursors. The complexes show intense absorptions throughout the UV/Vis region and also exhibit luminescence at room temperature. The redox behavior of the compounds is characterized by several metal-centered reversible oxidation and ligand-centered reduction processes. Steady-state and time-resolved luminescence data show that the potentially luminescent Ru(II)- and Os(II)-based triplet metal-to-ligand charge-transfer ((3)MLCT) excited states in the triads are quantitatively quenched, most likely by intercomponent energy transfer to the lower lying (3)MLCT (for Ru and Os) or triplet metal-centered ((3)MC) excited states of the Fe(II) subunit (nonluminescent). Interestingly, iron did not adversely affect the photophysics of the respective systems. This suggests that the multicomponent molecular-wire-like complexes investigated here can behave as efficient light-harvesting antennas, because all the light absorbed by the various subunits is efficiently channeled to the subunit(s) in which the lowest-energy excited states are located. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Design, spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases

    Science.gov (United States)

    Hanif, Muhammad; Chohan, Zahid H.

    2013-03-01

    A new series of three biologically active triazole derived Schiff base ligands L1-L3 have been synthesized in equimolar reaction of 3-amino-1H-1,2,4-triazole with pyrrol-2-carboxaldehyde, 4-bromo-thiophene-2-carboxaldehyde, and 5-iodo-2-hydroxy benzaldehyde. The prepared Schiff bases were used for further complex formation reaction with different metal elements like Co(II), Ni(II), Cu(II) and Zn(II) as chlorides by using a molar ratio of ligand:metal as 2:1. The structure and bonding nature of all the compounds were identified by their physical, spectral and analytical data. All the metal(II) complexes possessed an octahedral geometry except the Cu(II) complexes which showed a distorted octahedral geometry. All the synthesized compounds, were studied for their in vitro antibacterial, and antifungal activities, against four Gram-negative (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and against six fungal strains (Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata) by using agar-well diffusion method. It has been shown that all the synthesized compounds showed moderate to significant antibacterial activity against one or more bacterial strains. In vitro Brine Shrimp bioassay was also carried out to investigate the cytotoxic properties of these compounds. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination.

  18. Studies on Zn(II monohydroxyphenyl mesoporphyrinic complexes. Synthesis and characterization

    Directory of Open Access Journals (Sweden)

    RICA BOSCENCU

    2008-07-01

    Full Text Available A series of four Zn(II complexes with asymmetrical porphyrinic ligands were synthesized: [5-(4-hydroxyphenyl-10,15,20-triphenyl-21H,23H-porphinato]Zn(II (Zn(IITPPOHP, [5-(3-hydroxyphenyl-10,15,20-triphenyl-21H,23H-porphinato]Zn(II (Zn(IITPPOHM, [5-(2-hydroxyphenyl-10,15,20-triphenyl-21H,23H-Zn(II-porphinato]Zn(II (Zn(IITPPOHO and the well-known (5,10,15,20-tetraphenyl-21H,23H-porphinato]Zn(II (Zn(IITPP as reference, in a 1:1 mole ratio. In all cases, the free-base porphyrin served as a tetradentate ligand through the four pyrrole nitrogen atoms. The complexes were characterized by elemental analysis, FTIR and UV–Vis spectroscopy, which fully confirmed the structure of the complexes. UV–Vis showed that the spectral absorption of the four complexes was blue-shifted by at least 50 nm compared to that of the free ligands. Also important structural data were obtained from several different NMR experiments (including 1H-NMR, 13C-NMR, DEPT, COSY, HMBC and HMQC. Influences of external substituents on the porphyrin ring were observed.

  19. Hydride Reactivity of Ni-II-X-Ni-II Entities : Mixed-Valent Hydrido Complexes and Reversible Metal Reduction

    NARCIS (Netherlands)

    Gehring, Henrike; Metzinger, Ramona; Herwig, Christian; Intemann, Julia; Harder, Sjoerd; Limberg, Christian

    After the lithiation of PYR-H2 (PYR2-=[{NC(Me)C(H)C(Me)NC6H3(iPr)2}2(C5H3N)]2-), which is the precursor of an expanded beta-diketiminato ligand system with two binding pockets, its reaction with [NiBr2(dme)] led to a dinuclear nickel(II)bromide complex, [(PYR)Ni(mu-Br)NiBr] (1). The bridging bromide

  20. Asymmetric Ruthenium(II and Osmium(II Complexes with New Bidentate Polyquinoline Ligands. Synthesis and NMR Characterization

    Directory of Open Access Journals (Sweden)

    Antonino Mamo

    2010-03-01

    Full Text Available A series of Ru(II and Os(II tris-chelate complexes with new bidentate 2-pyridylquinoline ligands have been synthesized and fully characterized by EA,1H-NMR and FAB-MS techniques. The new ligands are: L1 = 4-p-methoxyphenyl-6-bromo-2-(2′- pyridylquinoline (mphbr-pq and L2 = 4-p-hydroxyphenyl-6-bromo-2-(2′-pyridyl-quinoline (hphbr-pq. The complexes studied are: [Ru(bpy2L1](PF62 (C1, [Ru(bpy2L2](PF62 (C2, [Os(bpy2L1](PF62 (C3, [Os(bpy2L2](PF62 (C4 (bpy = 2,2′-bipyridine, [Ru(dmbpy2L1](PF62 (C5, [Ru(dmbpy2L2](PF62 (C6, [Os(dmbpy2L1](PF62 (C7, and [Os(dmbpy2L2](PF62 (C8 (dmbpy = 4,4′-dimethyl-2,2′-bipyridine. Moreover, new functionalized complexes C9-C12 were obtained by the basecatalyzed direct alkylation of C2, C4, C6, and C8 with 6-bromo-1-hexene. The complete assignment of the 1H-NMR spectra for the two new ligands (L1 and L2, and their Ru(II or Os(II complexes has been accomplished using a combination of one- and two-dimensional NMR techniques. The JH,H values have been determined for the majority of the resonances.

  1. Studies on nickel (II and palladium (II complexes with some tetraazamacrocycles containing tellurium

    Directory of Open Access Journals (Sweden)

    Rathee Nitu

    2012-01-01

    Full Text Available The synthesis of 10-membered and 12-membered tellurium containing tetraazamacrocyclic complexes of divalent nickel and palladium by template condensation of diaryltellurium dichlorides, (aryl = p-hydroxyphenyl, 3-methyl-4-hydroxyphenyl, p-methoxyphenyl with 1,2-diaminoethane and 1,3-diaminopropane in the presence of metal dichloride is reported. The resulting complexes have been subjected to elemental analyses, magnetic measurements, electronic absorption, infra-red, and proton magnetic resonance spectral studies. The formation of proposed macrocyclic skeletons and their donor sites have been identified on the basis of spectral studies. Distorted octahedral structure for the nickel complexes in the solid state and squareplanar structure for the palladium complexes have been suggested.

  2. Studies of Ni(II) & Cu(II) complexes with ampicillin | Guru | Nigerian ...

    African Journals Online (AJOL)

    On the basis of elemental analysis and molar conductance, formulas Ni(C16H19 N3O4S)MoO4H2O and Cu(C16H19N3O4S)MoO4H2O have been suggested for the complexes under study. The geometries of the complexes have been proposed on the basis of magnetic moment, electronic and infrared spectral data.

  3. Two photon absorption energy transfer in the light-harvesting complex of photosystem II (LHC-II) modified with organic boron dye.

    Science.gov (United States)

    Chen, Li; Liu, Cheng; Hu, Rui; Feng, Jiao; Wang, Shuangqing; Li, Shayu; Yang, Chunhong; Yang, Guoqiang

    2014-07-15

    The plant light-harvesting complexes of photosystem II (LHC-II) play important roles in collecting solar energy and transferring the energy to the reaction centers of photosystems I and II. A two photon absorption compound, 4-(bromomethyl)-N-(4-(dimesitylboryl)phenyl)-N-phenylaniline (DMDP-CH2Br), was synthesized and covalently linked to the LHC-II in formation of a LHC-II-dye complex, which still maintained the biological activity of LHC-II system. Under irradiation with femtosecond laser pulses at 754 nm, the LHC-II-dye complex can absorb two photons of the laser light effectively compared with the wild type LHC-II. The absorbed excitation energy is then transferred to chlorophyll a with an obvious fluorescence enhancement. The results may be interesting and give potentials for developing hybrid photosystems. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Influence of the 33 kDa manganese-stabilizing protein on the structure and substrate accessibility of the oxygen-evolving complex of photosystem II.

    Science.gov (United States)

    Gregor, Wolfgang; Cinco, Roehl M; Yu, Hui; Yachandra, Vittal K; Britt, R David

    2005-06-21

    The 33 kDa manganese-stabilizing extrinsic protein binds to the lumenal side of photosystem II (PS II) close to the Mn(4)Ca cluster of the oxygen-evolving complex, where it limits access of small molecules to the metal site. Our previous finding that the removal of this protein did not alter the magnetic coupling regime within the manganese cluster, measured by electron spin-echo envelope modulation [Gregor, W., and Britt, R. D. (2000) Photosynth. Res. 65, 175-185], prompted us to examine whether this accessibility control is also true for substrate water, using the same pulsed EPR technique. Comparing the deuteron modulation of the S(2)-state multiline signal of PS II membranes, equilibrated with deuterated water (D(2)O) after removal or retention of the 33 kDa protein, we observed no change in the number and the distance of deuterons magnetically coupled to manganese, indicating that the number and distance of water molecules bound to the manganese cluster are independent of bound 33 kDa protein in the S(1) state, in which the sample was poised prior to cryogenic illumination. A simple modulation depth analysis revealed a distance of 2.5-2.6 A between the closest deuteron and manganese. These results are in agreement with our refined X-ray absorption analysis. The manganese K-edge positions, reflecting their oxidation states, and the extended X-ray absorption fine structure amplitudes and distances between the manganese ions and their oxygen and nitrogen ligands (1.8, 2.7, and 3.3-3.4 A) were independent of bound 33 kDa protein.

  5. The regulation of TiO2 nanoparticles on the expression of light-harvesting complex II and photosynthesis of chloroplasts of Arabidopsis thaliana.

    Science.gov (United States)

    Ze, Yuguan; Liu, Chao; Wang, Ling; Hong, Mengmeng; Hong, Fashui

    2011-11-01

    Recent studies demonstrated that titanium dioxide nanoparticles (TiO2 NPs) could significantly promote photosynthesis and plant growth, but its mechanism is still unclear. In this article, we studied the mechanism of light absorption and transfer of chloroplasts of Arabidopsis thaliana caused by TiO2 NPs treated. The results showed that TiO2 NPs could induce significant increases of light-harvesting complex II (LHCII) b gene expression and LHCII II content on the thylakoid membrane in A. thaliana, and the increases in LHCII were higher than the non-nano TiO2 (bulk-TiO2) treatment. Meanwhile, spectroscopy assays indicated that TiO2 NPs obviously increased the absorption peak intensity of the chloroplast in red and blue region, the fluorescence quantum yield near 680 nm, the excitation peak intensity near 440 and 480 nm and/or near 650 and 680 nm of the chloroplast. TiO2 NPs treatment could reduce F480/F440 ratio and increase F650/F680 ratio and accelerate the rate of whole chain electron transport and oxygen evolution of the chloroplast. However, the photosynthesis improvement of the non-nanoTiO2 treatment was far less effective than TiO2 NPs treatment. Taken together, TiO2 NPs could promote the light absorption of chloroplast, regulate the distribution of light energy from PS I to PS II by increasing LHCII and accelerate the transformation from light energy to electronic energy, water photolysis, and oxygen evolution.

  6. PS1-23: Capitalizing on the HMO Cancer Research Network (CRN): The Optimal Setting to Conduct Studies of Rare Complex Diseases

    Science.gov (United States)

    Johnson, Christine Cole; Chao, Chun; Engel, Larry; Feigelson, Heather; Fortuny, Joan; Habel, Laurel; Koshiol, Jill; Roblin, Douglas; Spangler, Leslie; Wells, Karen; Yood, Marianne Ulcickas

    2013-01-01

    Background/Aims Rare cancers are challenging to study, both epidemiologically and clinically, as it is difficult to ascertain enough cases to achieve adequate statistical power or to be representative of a vast range of exposures. Further, as the complexity of unraveling the natural history of disease has increased, a large investigator team with diverse expertise is required to optimize the scientific contributions that can be mined from research projects. The HMOCRN provides a setting that can overcome these barriers. Although many studies evaluate all lymphomas combined, lymphoma consists of over 50 rare histological subtypes with varying incidence and survival rates and epidemiological features. Ideally, each histological subtype should be considered separately in etiological studies, but even the most common, diffuse large B cell lymphoma, has a SEER incidence of only 7.5 per 100,000 in men and 5.0 per 100,000 in women. Other lymphoma types range in incidence from intellectual capital from numerous HMOCRN investigators and external collaborators.

  7. Ruthenium (II) complexes of thiosemicarbazone: Synthesis, biosensor applications and evaluation as antimicrobial agents

    Energy Technology Data Exchange (ETDEWEB)

    Yildirim, Hatice [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Buca, Izmir (Turkey); Guler, Emine [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Yavuz, Murat, E-mail: myavuz@dicle.edu.tr [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Dicle University, Faculty of Science, Department of Chemistry, 21280 Diyarbakir (Turkey); Ozturk, Nurdan; Kose Yaman, Pelin [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Buca, Izmir (Turkey); Subasi, Elif; Sahin, Elif [Dokuz Eylul University, Faculty of Science, Department of Chemistry, 35160 Buca, Izmir (Turkey); Timur, Suna [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Ege University, Institute on Drug Abuse, Toxicology and Pharmaceutical Science (BATI), 35100 Bornova, Izmir (Turkey)

    2014-11-01

    A conformationally rigid half-sandwich organoruthenium (II) complex [(η{sup 6}-p-cymene)RuClTSC{sup N–S}]Cl, (1) and carbonyl complex [Ru(CO)Cl(PPh{sub 3}){sub 2}TSC{sup N–S}] (2) have been synthesized from the reaction of [{(η"6-p-cymene)RuCl}{sub 2}(μ-Cl){sub 2}] and [Ru(H)(Cl)(CO)(PPh{sub 3}){sub 3}] with thiophene-2-carboxaldehyde thiosemicarbazon (TSC) respectively and both novel ruthenium (II) complexes have been characterized by elemental analysis, FT-IR and NMR spectroscopy. The peripheral TSC in the complexes acts as an electrochemical coupling unit providing the ability to carry out electrochemical deposition (ED) and to form an electro-deposited film on a graphite electrode surface. The biosensing applicability of complexes 1 and 2 was investigated by using glucose oxidase (GOx) as a model enzyme. Electrochemical measurements at − 0.9 V versus Ag/AgCl electrode by following the ED Ru(II) reduction/oxidation due to from the enzyme activity, in the presence of glucose substrate. The designed biosensor showed a very good linearity for 0.01–0.5 mM glucose. The in vitro antimicrobial activities of complexes 1 and 2 were also investigated against nine bacterial strains and one fungus by the disc diffusion test method. No activity was observed against the Gram-negative strains and fungus, whereas complex 1 showed moderate antibacterial activities against Gram-positive bacterial strains. - Highlights: • Novel Ru (II) thiosemicarbazone complexes were synthesized and characterized. • Electrochemical depositions were performed. • Rigid half-sandwich Ru (II) complex showed enhanced antibacterial activity.

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

    Science.gov (United States)

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

    2005-01-01

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

  9. Interplay of bifurcated hydrogen bonds in making of inclusion/pseudo-inclusion complexes of Ni(II), Cu(II) and Zn(II) of a salophen type ligand: Crystal structures and spectral aspects

    Science.gov (United States)

    Ambili, K. U.; Sithambaresan, M.; Kurup, M. R. Prathapachandra

    2017-04-01

    Three novel photoluminescent materials were synthesized by treating Ni(II), Cu(II) and Zn(II) acetate salts with a Schiff base prepared from 3-ethoxysalicylaldehyde and 2-aminobenzylamine. Among the prepared complexes, Ni(II) and Cu(II) complexes are inclusion compounds while Zn(II) complex is a pseudo-inclusion compound. They were characterized by elemental analysis, IR, UV-visible and EPR spectra. Single crystal XRD studies of these complexes suggest that Ni(II) and Cu(II) are in a distorted square planar environment while the spatial arrangement of donor atoms in Zn(II) complex is best described as distorted square based pyramid although significant distortion towards trigonal bipyramid is noticed. Stabilized crystal packing of the complexes is established via supramolecular interactions. The metal chelate rings as the π system for C-H···π interactions found in Cu(II) and Zn(II) complexes explicit the concept of metalloaromaticity. TG-DTG studies reveal that all the complexes are thermally stable. Both ligand and complexes exhibit intense photoluminescence in near UV region. However, Zn(II) complex giving an intense blue-green emission spectrum at maximum wavelength of 518 nm with shoulder peaks, could be used for optoelectronic applications.

  10. Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, Miriam M.; Zhang, Cheng; Tan, Howe-Siang, E-mail: howesiang@ntu.edu.sg [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Akhtar, Parveen; Garab, Győző; Lambrev, Petar H., E-mail: lambrev@brc.hu [Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged (Hungary)

    2015-06-07

    The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Q{sub y} band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240–270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet–singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state.

  11. A Bloch equation approach to intensity dependent optical spectra of light harvesting complex II: excitation dependence of light harvesting complex II pump-probe spectra.

    Science.gov (United States)

    Richter, Marten; Renger, Thomas; Knorr, Andreas

    2008-01-01

    On the basis of the recent progress in the resolution of the structure of the antenna light harvesting complex II (LHC II) of the photosystem II, we propose a microscopically motivated theory to predict excitation intensity-dependent spectra. We show that optical Bloch equations provide the means to include all 2( N ) excited states of an oligomer complex of N coupled two-level systems and analyze the effects of Pauli Blocking and exciton-exciton annihilation on pump-probe spectra. We use LHC Bloch equations for 14 Coulomb coupled two-level systems, which describe the S (0) and S (1) level of every chlorophyll molecule. All parameter introduced into the Hamiltonian are based on microscopic structure and a quantum chemical model. The derived Bloch equations describe not only linear absorption but also the intensity dependence of optical spectra in a regime where the interplay of Pauli Blocking effects as well as exciton-exciton annihilation effects are important. As an example, pump-probe spectra are discussed. The observed saturation of the spectra for high intensities can be viewed as a relaxation channel blockade on short time scales due to Pauli blocking. The theoretical investigation is useful for the interpretation of the experimental data, if the experimental conditions exceed the low intensity pump limit and effects like strong Pauli Blocking and exciton-exciton annihilation need to be considered. These effects become important when multiple excitations are generated by the pump pulse in the complex.

  12. Structural and spectroscopic characterization of two new Cd(II) complexes: bis(thiosaccharinato)bis(imidazole) cadmium(II) and tris(thiosaccharinato)aquacadmate(II)

    Science.gov (United States)

    Tarulli, S. H.; Quinzani, O. V.; Baran, E. J.; Piro, O. E.; Castellano, E. E.

    2003-08-01

    The crystal structures of [Cd(tsac)2(im)2] (1) (tsac=anion of thiosaccharine; im=imidazole) and of (Him)[Cd(tsac)3(H2O)] (2) (Him=imidazolium cation) have been determined at 120 K by single crystal X-ray diffractometry. Complex 1 crystallises in the monoclinic space group P21/a with Z=4 whereas compound 2 is triclinic, space group P(-1) and Z=2. In both compounds, Cd(II) is in a distorted tetrahedral environment. In the neutral complex 1 the metal is coordinated to the S-atom of the two thiosaccharinato ligands and to the N-atom of the imidazole molecules. In the anionic complex 2, Cd(II) is coordinated to three thiosaccharinato S-atoms and to the O-atom of the water molecule. The FTIR spectra of both compounds were also recorded and briefly discussed.

  13. Synthesis, spectral characterization and biological activities of Mn(II) and Co(II) complexes with benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone

    Science.gov (United States)

    Prathima, B.; Subba Rao, Y.; Ramesh, G. N.; Jagadeesh, M.; Reddy, Y. P.; Chalapathi, P. V.; Varada Reddy, A.

    2011-06-01

    Mn(II) and Co(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone have been synthesized and characterized by the investigations of electronic and EPR spectra and X-ray diffraction. Based on the spectral studies, an octahedral geometry is assigned for the Mn(II) and Co(II) complexes. X-ray powder diffraction studies reveal that Mn(II) and Co(II) complexes have triclinic crystal lattices. The unit cell parameters of the Mn(II) complex are a = 11.0469 Å, b = 6.2096 Å, c = 7.4145 Å, α = 90.646°, β = 95.127°, γ = 104.776°, V = 489.7 Å 3 and those of Co(II) complex are a = 9.3236 Å, b = 10.2410 Å, c = 7.8326 Å, α = 90.694°, β = 99.694°, γ = 100.476°, V = 724.2 Å 3. When the free ligand and its metal complexes are subjected to antibacterial activity, the metal complexes are proved to be more active than the ligand. However with regard to in vitro antioxidant activity, the ligand exhibits greater antioxidant activity than its metal(II) complexes.

  14. DNA damaging, cell cytotoxicity and serum albumin binding efficacy of the rutin-Cu(ii) complex.

    Science.gov (United States)

    Roy, Atanu Singha; Tripathy, Debi Ranjan; Samanta, Sintu; Ghosh, Sudip K; Dasgupta, Swagata

    2016-04-26

    Flavonoids are widely used as anti-oxidants, anti-cancer agents and possess metal ion chelation properties. In this report we have investigated the DNA binding (and damaging), cell cytotoxicity and serum albumin (SA) binding efficacy of the rutin-Cu(ii) complex using differential spectroscopic methods. The rutin-Cu(ii) complex was able to intercalate into calf thymus DNA (ct-DNA) at lower concentrations and its DNA damaging properties were also confirmed from the agarose gel based assay, fluorescence and UV-vis studies. The copper complex was found to be effective against the growth of HeLa cells in vivo. The binding constants (Kb) of the rutin-Cu(ii) complex towards HSA and BSA were found to be (0.98 ± 0.03) and (1.05 ± 0.02) × 10(5) M(-1), respectively, at 299 K and observed to increase with the increase in temperature. Site selectivity studies revealed that the rutin-Cu(ii) complex binds near site 1 (subdomain IIA) of SAs. Thermodynamic parameters indicated that the mode of interaction of rutin and its copper complex with SAs are different from each other. Both ΔH° and ΔS° were observed to be positive for the interaction of the rutin-Cu(ii) complex with SAs, indicating the presence of hydrophobic association in binding. The values of ΔH° were estimated to be negative (-42.07 ± 2.92 and -23.29 ± 2.33 kJ mol(-1) for HSA and BSA respectively) in the binding of rutin with SAs. It implies that after chelation with Cu(ii) ion, rutin alters its binding mode which could have varying applications to its other physicochemical activities.

  15. Synthesis and characterization of monomeric and dimeric manganese(II and zinc(II complexes of pyridine-2-carbaldoxime

    Directory of Open Access Journals (Sweden)

    Jørgen Glerup

    2000-12-01

    Full Text Available The syntheses and characterization of two complexes of manganese(II and one complex of zinc(II with the ligand pyridine-2-carbaldoxime, C6H6N2O, are described. The monomeric manganese(II complex cis-[Mn(C6H6N2O 2Cl2] (1 crystallizes in the orthorhombic space group Pbcn with 4 formula units in a cell of dimensions a = 12.479(3 Å, b = 10.348(2 Å, and c = 11. 974(2 Å. The structure has been refined to a final value of the conventional R-factor of 0.0330 based on 1513 observed independent reflections. The analogous zinc(II complex, cis-[Zn(C6H6N2O2Cl2] (2 also crystallizes in the orthorhombic space group Pbcn with 4 formula units in a cell of dimensions a = 12.215(2 Å, b = 10.383(2 Å, and c = 12. 016(2 Å. The structure has been refined to a final value of the conventional R-factor of 0.0377 based on 1117 observed independent reflections. The two complexes are isostructural, with the central metal atom lying on a crystallographic 2-fold axis. Both complexes are approximately octahedral, the coordination being provided by two trans pyridine nitrogen atoms and two cis amine nitrogen atoms from the oxime ligands, and by two cis chlorides. The dimeric manganese(II complex [(C6H6N2O(CH3OHClMnCl2MnCl(CH3OH(C6H6N2O] (3 crystallizes in the monoclinic space group P21/n with 2 formula units in a cell of dimensions a = 7.895(2 Å, b = 11.196(3 Å, and c = 12. 544(2 Å, and b = 98.39(2o. The structure has been refined to a final value of the conventional R-factor of 0.0312 based on 1568 observed independent reflections. There is a crystallographic inversion center in the middle of the dimer relating one manganese center to the other. The geometry at each manganese(II center is again roughly octahedral, coordination being provided by two nitrogen atoms from the oxime ligand, a terminal chloride ion trans to the amine nitrogen, the oxygen atom of the coordinated methanol molecule, and two bridging chlorides that link the two halves of the dimer. The Mn

  16. Synthesis, physical characterization and biological evaluation of Schiff base M(II complexes

    Directory of Open Access Journals (Sweden)

    Mahasin Alias

    2014-04-01

    Full Text Available Metal (II complexes of Cu, Ni, and Co with Schiff base derived from potassium 2-N (4-N,N-dimethylaminobenzyliden- 4-trithiocarbonate 1,3,4-thiadiazole (L were synthesized and characterized by standard physico-chemical procedures i.e. (metal analysis A.A, elemental chemical analysis C.H.N.S, FTIR, UV–vis, thermal analysis TGA, magnetic susceptibility and conductometric measurements. On the basis of these studies, a six coordinated octahedral geometry for all these complexes has been proposed. The Schiff base ligand and its complexes were also tested for their antibacterial activity to assess their inhibiting potential against Pseudomonas aeruginosa (as gram negative bacteria and Staphylococcus aureus (as gram positive bacteria using two different concentrations (5 and 10 mM. The results showed the Ni(II complex have the higher rate in antibacterial activity than other complexes and ligand when compared them with ampicillin as standard drug.

  17. Synthesis, XRD and spectroscopic characterization of pharmacologically active Cu(II) and Zn(II) complexes

    Science.gov (United States)

    Gull, Parveez; Hashmi, Athar Adil

    2017-07-01

    The present contribution accounts for the synthesis and structural elucidation of a newly synthesised copper and zinc containing schiff base compounds obtained by the condensation of 1, 2-diphenylethane-1, 2-dione and dinitrophenyl hydrazine as main ligand and benzene-1,2-diamine as co-ligand respectively. The synthesised compounds were characterized by several techniques, including elemental analysis, molar conductance and electronic, FT-IR, XRD, mass and 1H NMR spectral studies. The analytical and molar conductance values indicated that the complexes have square planar and tetrahedral geometry respectively. X-ray powder diffraction illustrates that they are crystalline in nature. The copper and zinc complexes were screened for their antimicrobial potential against some bacterial and fungi strains and the assay indicate that these complexes are good antimicrobial agents against these tested pathogens.

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

    Science.gov (United States)

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

    2014-10-01

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

  19. Indole-7-carbaldehyde thiosemicarbazone as a flexidentate ligand toward ZnII, CdII, PdII and PtII ions: cytotoxic and apoptosis-inducing properties of the PtII complex.

    Science.gov (United States)

    Ibrahim, Abeer A; Khaledi, Hamid; Hassandarvish, Pouya; Mohd Ali, Hapipah; Karimian, Hamed

    2014-03-14

    A new thiosemicarbazone (LH2) derived from indole-7-carbaldehyde was synthesized and reacted with Zn(II), Cd(II), Pd(II) and Pt(II) salts. The reactions with zinc and cadmium salts in 2 : 1 (ligand-metal) molar ratio afforded complexes of the type MX2(LH2)2, (X = Cl, Br or OAc), in which the thiosemicarbazone acts as a neutral S-monodentate ligand. In the presence of potassium hydroxide, the reaction of LH2 with ZnBr2 resulted in deprotonation of the thiosemicarbazone at the hydrazine and indole nitrogens to form Zn(L)(CH3OH). The reaction of LH2 with K2PdCl4 in the presence of triethylamine, afforded Pd(L)(LH2) which contains two thiosemicarbazone ligands: one being dianionic N,N,S-tridentate while the other one is neutral S-monodentate. When PdCl2(PPh3)2 was used as the Pd(II) ion source, Pd(L)(PPh3) was obtained. In a similar manner, the analogous platinum complex, Pt(L)(PPh3), was synthesized. The thiosemicarbazone in the latter two complexes behaves in a dianionic N,N,S-tridentate fashion. The platinum complex was found to have significant cytotoxicity toward four cancer cells lines, namely MDA-MB-231, MCF-7, HT-29, and HCT-116 but not toward the normal liver WRL-68 cell line. The apoptosis-inducing properties of the Pt complex was explored through fluorescence microscopy visualization, DNA fragmentation analysis and propidium iodide flow cytometry.

  20. Palladium(II) and platinum(II) complexes containing benzimidazole ligands: Molecular structures, vibrational frequencies and cytotoxicity

    Science.gov (United States)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.

    2011-04-01

    (1H-benzimidazol-2-ylmethyl)-(4-methoxyl-phenyl)-amine (L 1), (1H-benzimidazol-2-ylmethyl)-(4-methyl-phenyl)-amine (L 2) and their Pd(II) and Pt(II) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using a variety of physico-chemical techniques. Theoretical calculations invoking geometry optimization, vibrational assignments, 1H NMR, charge distribution and molecular orbital description HOMO and LUMO were done using density functional theory. Natural bond orbital analysis (NBO) method was performed to provide details about the type of hybridization and the nature of bonding in the studied complexes. Strong coordination bonds (LP(1)N11 → σ *(M sbnd Cl22)) and (LP(1)N21 → σ *(M sbnd Cl23)) (M = Pd or Pt) result from donation of electron density from a lone pair orbital on the nitrogen atoms to the acceptor metal molecular orbitals. The experimental results and the calculated molecular parameters revealed square-planar geometries around the metallic centre through the pyridine-type nitrogen of the benzimidazole ring and secondary amino group and two chlorine atoms. The activation thermodynamic parameters were calculated using non-isothermal methods. The synthesized ligands, in comparison to their metal complexes were screened for their antibacterial activity. In addition, the studied complexes showed activity against three cell lines of different origin, breast cancer (MCF-7), Colon Carcinoma (HCT) and human heptacellular carcinoma (Hep-G2) comparable to cis-platin.

  1. Spectroscopic and theoretical study of Cu(II), Zn(II), Ni(II), Co(II) and Cd(II) complexes of glyoxilic acid oxime

    Science.gov (United States)

    Georgieva, Ivelina; Trendafilova, Natasha; Bauer, Günther

    2006-02-01

    The paper presents a detailed experimental and theoretical study of five metal complexes of glyoxilic acid oxime (gaoH 2), Cu(gaoH) 2(H 2O) 2 ( 1), Zn(gaoH) 2(H 2O) 2 ( 2), Co(gaoH) 2(H 2O) 2 ( 3), Ni(gaoH) 2(H 2O) 2 ( 4) and [Cd(gaoH) 2(H 2O) 2]·H 2O ( 5). The electronic and vibrational spectra were measured and discussed as to the most sensitive to the M-L binding bands. Two different types of coordination were considered for gaoH - ligand: bidentate through the carboxylic oxygen and oxime nitrogen in 1- 4 and mixed bidentate and bridging through the COO group in 5. It is shown that the spectral behavior of the ν(COO) modes can be used to predict bridging ligand coordination. DFT(B3LYP/6-31++G(d,p)) calculations on model compounds: neutral, anionic and radical forms of gao and Cu(gaoH) 2, have been carried out to correlate geometries, electronic and vibrational structures. The results obtained were used to assist the electronic and vibrational analysis of the complexes studied. The effect of the metal-ligand interactions (electrostatic and covalent) on the geometry structure of the ligand was investigated.

  2. Antibacterial activity of Pd(II) complexes with salicylaldehyde-amino acids Schiff bases ligands.

    Science.gov (United States)

    Rîmbu, Cristina; Danac, Ramona; Pui, Aurel

    2014-01-01

    Palladium(II) complexes with Schiff bases ligands derived from salicylaldehyde and amino acids (Ala, Gly, Met, Ser, Val) have been synthesized and characterized by Fourier transform (FT)-IR, UV-Vis and (1)H-NMR spectroscopy. The electrospray mass spectrometry (ES-MS) spectrometry confirms the formation of palladium(II) complexes in 1/2 (M/L) molar ratio. All the Pd(II) complexes 1, [Pd(SalAla)2]Cl2; 2, [Pd(SalGly)2]Cl2; 3, [Pd(SalMet)2]Cl2; 4, [Pd(SalSer)2]Cl2; 5, [Pd(SalVal)2]Cl2; have shown antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli.

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

    Science.gov (United States)

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

    2004-05-31

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

  4. Mössbauer study of novel iron(II) complexes synthesized with Schiff bases

    Science.gov (United States)

    Várhelyi, Cs.; Lengyel, A.; Homonnay, Z.; Szalay, R.; Pokol, Gy.; Szilágyi, I.-M.; Huszthy, P.; Papp, J.; Goga, F.; Golban, L.-M.; Várhelyi, M.; Tomoaia-Cotisel, M.; Szőke, Á.; Kuzmann, E.

    2017-11-01

    Novel [Fe(4-benzyl-2-hydroxyphenyl-propylidene)2ethylene-diamine], and [Fe (2,4,6-trihydroxy-benzyl-4-metoxiphenyl-methylidene)2ethylene-diamine] complexes were synthesized by reacting FeII salt with the indicated Schiff-base ligands. The compounds were characterized by57Fe Mössbauer spectroscopy, FTIR, UV-VIS, TG-DTA-DTG, MS, AFM, XRD, cyclic voltammetry and biological activity measurements. 295 K and 78 K Mössbauer spectra revealed that iron is dominantly in high spin FeII state in both complexes while simultaneously a minor low spin FeII was also present in both complexes, furthermore a minor high spin FeIII was observed in [Fe(2,4,6-trihydroxy-benzyl-4-metoxiphenyl- methylidene) 2ethylene-diamine], too.

  5. Cobalt(II), nickel(II) and copper(II) complexes of a hexadentate pyridine amide ligand. Effect of donor atom (ether vs. thioether) on coordination geometry, spin-state of cobalt and M(III)-M(II) redox potential.

    Science.gov (United States)

    Pandey, Sharmila; Das, Partha Pratim; Singh, Akhilesh Kumar; Mukherjee, Rabindranath

    2011-10-28

    Using an acyclic hexadentate pyridine amide ligand, containing a -OCH(2)CH(2)O- spacer between two pyridine-2-carboxamide units (1,4-bis[o-(pyrydine-2-carboxamidophenyl)]-1,4-dioxabutane (H(2)L(9)), in its deprotonated form), four new complexes, [Co(II)(L(9))] (1) and its one-electron oxidized counterpart [Co(III)(L(9))][NO(3)]·2H(2)O (2), [Ni(II)(L(9))] (3) and [Cu(II)(L(9))] (4), have been synthesized. Structural analyses revealed that the Co(II) centre in 1 and the Ni(II) centre in 3 are six-coordinate, utilizing all the available donor sites and the Cu(II) centre in 4 is effectively five-coordinated (one of the ether O atoms does not participate in coordination). The structural parameters associated with the change in the metal coordination environment have been compared with corresponding complexes of thioether-containing hexadentate ligands. The μ(eff) values at 298 K of 1-4 correspond to S = 3/2, S = 0, S = 1 and S = 1/2, respectively. Absorption spectra for all the complexes have been investigated. EPR spectral properties of the copper(II) complex 4 have been investigated, simulated and analyzed. Cyclic voltammetric experiments in CH(2)Cl(2) reveal quasireversible Co(III)-Co(II), Ni(III)-Ni(II) and Cu(II)-Cu(I) redox processes. In going from ether O to thioether S coordination, the effect of the metal coordination environment on the redox potential values of Co(III)-Co(II) (here the effect of spin-state as well), Ni(III)-Ni(II) and Cu(II)-Cu(I) processes have been systematically analyzed.

  6. Superoxide-mediated Fe(II) formation from organically complexed Fe(III) in coastal waters

    Science.gov (United States)

    Fujii, Manabu; Ito, Hiroaki; Rose, Andrew L.; Waite, T. David; Omura, Tatsuo

    2008-12-01

    Fe(III) complexed by organic ligands (Fe(III)L) is the primary form of dissolved Fe in marine and coastal environments. Superoxide, typically produced in biological and photochemical processes, is one of the reducing agents that contributes to transformation of Fe(III)L to bioavailable, free dissolved Fe(II) (Fe(II)'). In this work, the kinetics of superoxide-mediated Fe(II)' formation from Fe(III)L in a simulated coastal water system were investigated and a comprehensive kinetic model was developed using citrate and fulvic acid as exemplar Fe-binding ligands. To simulate a coastal environment in laboratory experiments, Fe(III)L samples with various ligand/Fe ratios were incubated for 5 min to 1 week in seawater medium. At each ratio and incubation time, the rate of superoxide-mediated Fe(II)' formation was determined in the presence of the strong Fe(II) binding ligand ferrozine by spectrophotometrically measuring the ferrous-ferrozine complex generated at a constant concentration of superoxide. The Fe(II)' formation rate generally decreased with incubation time, as Fe(III)L gradually dissociated to form less reactive Fe(III) oxyhydroxide. However, when the ligand/Fe ratio was sufficiently high, the dissociation of Fe(III)L (and subsequent Fe precipitation) was suppressed and Fe(II)' was formed at a higher rate. The rate of Fe(II)' produced during the experiment was explained by the kinetic model. The model confirmed that both the ligand/Fe ratio and incubation time have a significant effect on the pathway via which Fe(II)' is formed from Fe(III)-fulvic acid complexes.

  7. SPS and PS Experiments Committee

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    OPEN SESSION: 09:00 Status report of NA58 / COMPASS: A. Magnon 09:40 Status report of PS212 / DIRAC: L. Tausher 10:10 PS212 / DIRAC Addendum: L. Nemenov CLOSED SESSION on Tuesday, 27 April 2004 after the open session, Main Building, 6th floor conference room

  8. Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10 ...

    Indian Academy of Sciences (India)

    DNA is related to their utility in the design and development of synthetic restriction enzymes, new drugs, DNA footprinting agents etc. and also to their ability to probe the structure of DNA itself1,2. In this regard, metal complexes have been found to be particularly useful because of their potential to bind DNA via a multitude of ...

  9. Anti-Leishmania activity of new ruthenium(II) complexes: Effect on parasite-host interaction.

    Science.gov (United States)

    Costa, Mônica S; Gonçalves, Yasmim G; Nunes, Débora C O; Napolitano, Danielle R; Maia, Pedro I S; Rodrigues, Renata S; Rodrigues, Veridiana M; Von Poelhsitz, Gustavo; Yoneyama, Kelly A G

    2017-10-01

    Leishmaniasis is a parasitic disease caused by protozoa of the genus Leishmania. The many complications presented by the current treatment - including high toxicity, high cost and parasite resistance - make the development of new therapeutic agents indispensable. The present study aims to evaluate the anti-Leishmania potential of new ruthenium(II) complexes, cis‑[RuII(η2-O2CR)(dppm)2]PF6, with dppm=bis(diphenylphosphino)methane and R=4-butylbenzoate (bbato) 1, 4-(methylthio)benzoate (mtbato) 2 and 3-hydroxy-4-methoxybenzoate (hmxbato) 3, in promastigote cytotoxicity and their effect on parasite-host interaction. The cytotoxicity of complexes was analyzed by MTT assay against Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis, Leishmania (Leishmania) infantum promastigotes and the murine macrophage (RAW 264.7). The effect of complexes on parasite-host interaction was evaluated by in vitro infectivity assay performed in the presence of two different concentrations of each complex: the promastigote IC50 value and the concentration nontoxic to 90% of RAW 264.7 macrophages. Complexes 1-3 exhibited potent cytotoxic activity against all Leishmania species assayed. The IC50 values ranged from 7.52-12.59μM (complex 1); 0.70-3.28μM (complex 2) and 0.52-1.75μM (complex 3). All complexes significantly inhibited the infectivity index at both tested concentrations. The infectivity inhibitions ranged from 37 to 85%. Interestingly, the infectivity inhibitions due to complex action did not differ significantly at either of the tested concentrations, except for the complex 1 against Leishmania (Leishmania) infantum. The infectivity inhibitions resulted from reductions in both percentage of infected macrophages and number of parasites per macrophage. Taken together the results suggest remarkable leishmanicidal activity in vitro by these new ruthenium(II) complexes. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. 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.

  11. Synthesis and characterization of new unsymmetrical 'side-off' tetra and hexa coordinate homobinuclear Cu(II) and heterobinuclear Cu(II)-Zn(II) complexes: Magnetic, electrochemical and kinetic studies

    Science.gov (United States)

    Shanmuga Bharathi, K.; Sreedaran, S.; Kalilur Rahiman, A.; Narayanan, V.

    A new class of phenol based unsymmetrical side-off tetra and hexa coordinate homobinuclear Cu(II) and heterobinuclear Cu(II)-Zn(II) complexes have been synthesized and characterized by elemental and spectral analysis. The electronic spectra of all the complexes show "Red shift" in LMCT band, for the ligand H2L2 compared to that of the ligand H2L1 due to the relatively higher electron donating nature of their substitutents. The homobinuclear Cu(II) complexes (1 and 2) illustrate an antiferromagnetic interaction (μeff: 1.58 and 1.60 BM) at 298 K with a broad EPR signal. Variable temperature magnetic moment study of the binuclear copper (II) complexes shows that the extent of antiferromagnetic coupling is greater in the case of H2L2 complexes than H2L1 complexes (-2 J values: 192 cm-1 and 184 cm-1 respectively). The heterobinuclear Cu(II)-Zn(II) complexes (3 and 4) have a magnetic moment value close to the spin only value with four hyperfine EPR signals. Electrochemical studies of the complexes reveal that all the binuclear complexes show two irreversible one-electron transfer reduction waves in the cathodic region. There is an "anodic shift" in the first reduction potential of the complexes, of the ligand H2L1 when compared to that of the ligand H2L2 due to the presence of relatively higher electron donating N-substituents in the later case than in the former case. The catecholase activity of the complexes reveals that the homobinuclear Cu(II) complexes show higher catalytic activity than the corresponding heterobinuclear Cu(II)-Zn(II) complexes. In the hydrolysis of 4-nitrophenylphosphate, the heterobinuclear Cu(II)-Zn(II) complexes show better catalytic activity than the corresponding homobinuclear Cu(II) complexes.

  12. Nickel(II) Complexes Bearing 4-Arylimino-1,2,3-trihydroacridines: Synthesis, Characterization, and Ethylene Oligomerization

    OpenAIRE

    Wang, Shengdong; Du, Shizhen; Zhang, Wenjuan; Asuha, Sin; Sun, Wen-Hua

    2015-01-01

    Nickel(II) complexes have attracted much attention as a new generation of olefin catalysts since the ?-diiminonickel complex was discovered as a highly efficient procatalyst for ethylene polymerization. A series of novel 4-arylimino-1,2,3-trihydroacridylnickel(II) dihalide complexes was synthesized in a one-pot reaction of 2,3-dihydroacridine-4-one and different anilines with nickel(II) chloride or nickel(II) bromide 1,2-dimethoxyethane complex. The complexes were characterized by infrared sp...

  13. The Libera as a PS orbit measurement system building block

    CERN Document Server

    Belleman, J M; CERN. Geneva. AB Department

    2005-01-01

    During the year 2004, extensive tests using a Libera data processor have been made in order to study its suitability as a building block for a complete PS trajectory and orbit measurement system. The Libera consists of four fast 12-bits ADCs, a Virtex II Pro FPGA and a large memory. This note presents some of the results of the analysis of acquisitions made on a position pick-up in the CERN PS.

  14. Alternative Ii-independent antigen-processing pathway in leukemic blasts involves TAP-dependent peptide loading of HLA class II complexes

    NARCIS (Netherlands)

    van Luijn, M.M.; Chamuleau, M.E.D.; Ressing, M.E.; Wiertz, E.J.; Ostrand-Rosenberg, S.; Souwer, Y.; Zevenbergen, A.; Ossenkoppele, G.J.; van de Loosdrecht, A.A.; Ham, S.M.

    2010-01-01

    During HLA class II synthesis in antigen-presenting cells, the invariant chain (Ii) not only stabilizes HLA class II complexes in the endoplasmic reticulum, but also mediates their transport to specialized lysosomal antigen-loading compartments termed MIICs. This study explores an alternative HLA

  15. Subtle conformational changes induced in major histocompatibility complex class II molecules by binding peptides.

    Science.gov (United States)

    Chervonsky, A V; Medzhitov, R M; Denzin, L K; Barlow, A K; Rudensky, A Y; Janeway, C A

    1998-08-18

    Intracellular trafficking of major histocompatibility complex (MHC) class II molecules is characterized by passage through specialized endocytic compartment(s) where antigenic peptides replace invariant chain fragments in the presence of the DM protein. These changes are accompanied by structural transitions of the MHC molecules that can be visualized by formation of compact SDS-resistant dimers, by changes in binding of mAbs, and by changes in T cell responses. We have observed that a mAb (25-9-17) that is capable of staining I-Ab on the surface of normal B cells failed to interact with I-Ab complexes with a peptide derived from the Ealpha chain of the I-E molecule but bound a similar covalent complex of I-Ab with the class II binding fragment (class II-associated invariant chain peptides) of the invariant chain. Moreover, 25-9-17 blocked activation of several I-Ab-reactive T cell hybridomas but failed to block others, suggesting that numerous I-Ab-peptide complexes acquire the 25-9-17(+) or 25-9-17(-) conformation. Alloreactive T cells were also able to discriminate peptide-dependent variants of MHC class II molecules. Thus, peptides impose subtle structural transitions upon MHC class II molecules that affect T cell recognition and may thus be critical for T cell selection and autiommunity.

  16. Crystal structure of subunit VPS25 of the endosomal trafficking complex ESCRT-II

    Directory of Open Access Journals (Sweden)

    Weissenhorn Winfried

    2004-12-01

    Full Text Available Abstract Background Down-regulation of plasma membrane receptors via the endocytic pathway involves their monoubiquitylation, transport to endosomal membranes and eventual sorting into multi vesicular bodies (MVB destined for lysosomal degradation. Successive assemblies of Endosomal Sorting Complexes Required for Transport (ESCRT-I, -II and III largely mediate sorting of plasma membrane receptors at endosomal membranes, the formation of multivesicular bodies and their release into the endosomal lumen. In addition, the human ESCRT-II has been shown to form a complex with RNA polymerase II elongation factor ELL in order to exert transcriptional control activity. Results Here we report the crystal structure of Vps25 at 3.1 Å resolution. Vps25 crystallizes in a dimeric form and each monomer is composed of two winged helix domains arranged in tandem. Structural comparisons detect no conformational changes between unliganded Vps25 and Vps25 within the ESCRT-II complex composed of two Vps25 copies and one copy each of Vps22 and Vps36 12. Conclusions Our structural analyses present a framework for studying Vps25 interactions with ESCRT-I and ESCRT-III partners. Winged helix domain containing proteins have been implicated in nucleic acid binding and it remains to be determined whether Vps25 has a similar activity which might play a role in the proposed transcriptional control exerted by Vps25 and/or the whole ESCRT-II complex.

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

    Science.gov (United States)

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

    2001-04-01

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

  18. Structural and spectroscopic characterization of iron(II), cobalt(II), and nickel(II) ortho-dihalophenolate complexes: insights into metal-halogen secondary bonding.

    Science.gov (United States)

    Machonkin, Timothy E; Boshart, Monica D; Schofield, Jeremy A; Rodriguez, Meghan M; Grubel, Katarzyna; Rokhsana, Dalia; Brennessel, William W; Holland, Patrick L

    2014-09-15

    Metal complexes incorporating the tris(3,5-diphenylpyrazolyl)borate ligand (Tp(Ph2)) and ortho-dihalophenolates were synthesized and characterized in order to explore metal-halogen secondary bonding in biorelevant model complexes. The complexes Tp(Ph2)ML were synthesized and structurally characterized, where M was Fe(II), Co(II), or Ni(II) and L was either 2,6-dichloro- or 2,6-dibromophenolate. All six complexes exhibited metal-halogen secondary bonds in the solid state, with distances ranging from 2.56 Å for the Tp(Ph2)Ni(2,6-dichlorophenolate) complex to 2.88 Å for the Tp(Ph2)Fe(2,6-dibromophenolate) complex. Variable temperature NMR spectra of the Tp(Ph2)Co(2,6-dichlorophenolate) and Tp(Ph2)Ni(2,6-dichlorophenolate) complexes showed that rotation of the phenolate, which requires loss of the secondary bond, has an activation barrier of ~30 and ~37 kJ/mol, respectively. Density functional theory calculations support the presence of a barrier for disruption of the metal-halogen interaction during rotation of the phenolate. On the other hand, calculations using the spectroscopically calibrated angular overlap method suggest essentially no contribution of the halogen to the ligand-field splitting. Overall, these results provide the first quantitative measure of the strength of a metal-halogen secondary bond and demonstrate that it is a weak noncovalent interaction comparable in strength to a hydrogen bond. These results provide insight into the origin of the specificity of the enzyme 2,6-dichlorohydroquinone 1,2-dioxygenase (PcpA), which is specific for ortho-dihalohydroquinone substrates and phenol inhibitors.

  19. Back to work for the PS

    CERN Multimedia

    2006-01-01

    On 22 June, the PS's rotating machine started turning again for the first time since its enforced shutdown one month ago (see Bulletin No. 23-24/2006) - and the PS was back in operation the very next day! A team from Siemens worked their socks off, 6 days a week for one month (including public holidays), to repair the electrical power supply in collaboration with the AB/PO Group's Main Power Converters (MPC) Section. The generator's faulty rotor was dismantled and replaced by the renovated spare rotor. The multitude of electrical and mechanical connections together with the sheer weight of the rotor (80 tonnes) made this an extremely complex job. The AB/PO Group used the shutdown to test a back-up solution for the PS power supply. The accelerator was directly wired up to the 18 kV electrical network via a 13 MVA transformer, installed at the end of the 1970s but never used. This solution succeeded in bringing the PS back into operation but at limited energy and frequency. Just 14 GeV could be achieved, whic...

  20. Antiproliferative effect of novel platinum(II) and palladium(II) complexes on hepatic tumor stem cells in vitro.

    Science.gov (United States)

    Miklášová, Natalia; Fischer-Fodor, Eva; Lönnecke, Peter; Tomuleasa, Ciprian Ionuţ; Virag, Piroska; Schrepler, Maria Perde; Mikláš, Roman; Dumitrescu, Luminiţa Silaghi; Hey-Hawkins, Evamarie

    2012-03-01

    Novel platinum and palladium complexes with (2-isopropoxyphenyl)dicyclohexylarsine and (2-methoxyphenyl)dicyclohexylarsine ligands were synthesized and tested on different tumor cells. Adducts with general formula MX(2)L(2) (M = Pt(II), Pd(II); X = Cl or I; L = organoarsenic ligand) were fully characterized. According to the crystallographic data, in all complexes the organoarsenic ligands coordinate the metal center through the arsenic atom only, in a trans arrangement with the halogen atoms. The antiproliferative potential of complexes 1-4 was evaluated in vitro on human tumor cell lines. A markedly biological activity was observed against the chemoresistant hepatic tumor stem cell line, the normal hepatic stem cells and towards the hepatocellular carcinoma (non-stem) cells. The new compounds toxicity is selectively limited in normal liver cells, unlikeness with the oxaliplatin, which displays a more intense effect in normal cells, compared with the two tumor cell lines. The stem cells treatment with compounds 1-4 causes DNA damages; the antimitotic effect of these compounds is based on their genotoxicity and on the capacity to form crosslinks with the DNA interstrand. In the case of platinum complexes 1 and 3 this mechanism gives rise to specific lesions on DNA that induces apoptosis in stem cells, influencing their selectivity in tumor cell growth inhibition. Compounds 1, 2 and 4 display higher activity against tumor stem cells. The novel platinum complexes 1 and 3 are more efficient against tumor stem cells than oxaliplatin, and if used in combination with sorafenib-based monoclonal anticancer therapy, complexes 1, 3 and 4 have the ability to induce superior chemosensitivity relative to sorafenib than the standard platinum-based drug, making them promising candidates for prodrug development. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  1. Multifunctional Zn(II) Complexes: Photophysical Properties and Catalytic Transesterification toward Biodiesel Synthesis.

    Science.gov (United States)

    Gupta, Abhishek Kumar; Dhir, Abhimanew; Pradeep, Chullikkattil P

    2016-08-01

    Using 4-substituted derivatives of phenol-based compartmental Schiff-base hydroxyl-rich ligand, four multifunctional binuclear Zn(II) complexes have been synthesized and characterized. The photophysical properties of these complexes were explored in the solid state, in solutions, and in poly(methyl methacrylate) (PMMA) matrix, which revealed their good potential as tunable solid state emitters. Some of these complexes acted as efficient catalysts for the transesterification of esters and canola oil showing their potential in biodiesel generation. Mechanistic investigations using ESI-MS revealed that the transesterification catalyzed by these complexes proceeds through two types of acyl intermediates.

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

    Directory of Open Access Journals (Sweden)

    Akinori Honda

    2016-10-01

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

  3. Spectrochemical study the effect of high energetic ionization radiation on Ru(III, Pd(II and Hg(II complexes

    Directory of Open Access Journals (Sweden)

    Samar A. Aly

    2017-04-01

    Thermal studies of these chelates before and after γ-irradiation stable that the complexes of Ru(III and Pd (II after γ-irradiation are more thermal show than Hg(II complexes before and after γ-irradiation.

  4. Synthesis, characterization, antimicrobial activity and carbonic anhydrase enzyme inhibitor effects of salicilaldehyde-N-methyl p-toluenesulfonylhydrazone and its Palladium(II), Cobalt(II) complexes

    Science.gov (United States)

    Alyar, Saliha; Adem, Şevki

    2014-10-01

    We report the synthesis of the ligand, salicilaldehyde-N-methyl p-toluenesulfonylhydrazone (salptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Pd(II) and Co(II) metal complexes were synthesized for the first time. The structure of the ligand and their complexes were investigated using elemental analysis, magnetic susceptibility, molar conductance and spectral (IR, NMR and LC-MS) measurements. Salptsmh has also been characterized by single crystal X-ray diffraction. 1H and 13C shielding tensors for crystal structure were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The complexes were found to have general composition [ML2]. The results of elemental analysis showed 1:2 (metal/ligand) stoichiometry for all the complex. Magnetic and spectral data indicate a square planar geometry for Pd(II) complex and a distorted tetrahedral geometry for Co(II) complexes. The ligand and its metal chelates have been screened for their antimicrobial activities using the disk diffusion method against the selected Gram positive bacteria: Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Gram negative bacteria: Eschericha coli, Pseudomonas aeruginosa, Klebsiella pneumonia. The inhibition activities of these compounds on carbonic anhydrase II (CA II) and carbonic anhydrase I (CA I) have been investigated by comparing IC50 and Ki values and it has been found that Pd(II) complex have more enzyme inhibition efficiency than salptsmh and Co(II) complex.

  5. Impaired ergosterol biosynthesis mediated fungicidal activity of Co(II) complex with ligand derived from cinnamaldehyde.

    Science.gov (United States)

    Shreaz, Sheikh; Shiekh, Rayees A; Raja, Vaseem; Wani, Waseem A; Behbehani, Jawad M

    2016-03-05

    In this study, we have used aldehyde function of cinnamaldehyde to synthesize N, N'-Bis (cinnamaldehyde) ethylenediimine [C20H20N2] and Co(II) complex of the type [Co(C40H40N4)Cl2]. The structures of the synthesized compounds were determined on the basis of physiochemical analysis and spectroscopic data ((1)H NMR, FTIR, UV-visible and mass spectra) along with molar conductivity measurements. Anticandidal activity of cinnamaldehyde its ligand [L] and Co(II) complex was investigated by determining MIC80, time-kill kinetics, disc diffusion assay and ergosterol extraction and estimation assay. Ligand [L] and Co(II) complex are found to be 4.55 and 21.0 folds more efficient than cinnamaldehyde in a liquid medium. MIC80 of Co(II) complex correlated well with ergosterol inhibition suggesting ergosterol biosynthesis to be the primary site of action. In comparison to fluconazole, the test compounds showed limited toxicity against H9c2 rat cardiac myoblasts. In confocal microscopy propidium iodide (PI) penetrates the yeast cells when treated with MIC of metal complex, indicating a disruption of cell membrane that results in imbibition of dye. TEM analysis of metal complex treated cells exhibited notable alterations or damage to the cell membrane and the cell wall. The structural disorganization within the cell cytoplasm was noted. It was concluded that fungicidal activity of Co(II) complex originated from loss of membrane integrity and a decrease in ergosterol content is only one consequence of this. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Preparation and characterization of Schiff base Cu(II) complex and its applications on textile materials

    Science.gov (United States)

    Oylumluoglu, G.; Oner, J.

    2017-10-01

    Schiff base ligands are regarded as an important class of organic compounds on account of the fact that their complexation ability with transition metal ions. A new monomeric Schiff base Cu(II) complex, [Cu(HL)2], 1 [H2L = 2–((E)–(2–hydroxypropylimino)methyl)–4–nitrophenol] has been synthesized and characterized by elemental analysis, UV and IR spectroscopy, single crystal X-ray diffraction and photoluminescence study. While the Schiff base ligand and its Cu(II) complex are excited at λex = 349 nm in UV region, the Schiff base ligand shows a blue emission band at λmax = 480 nm whereas its Cu(II) complex shows a strong green emission band at λmax = 520 nm in the solid state at room temperature. The luminescent properties showed that the Schiff base ligand and its Cu(II) complex can be used as novel potential candidates for applications in textile such as UV-protection, antimicrobial, laundry and functional bleaching treatments.

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

    Science.gov (United States)

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

    2017-08-03

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

  8. Stability of binary complexes of Pb(II), Cd(II) and Hg(II) with maleic ...

    African Journals Online (AJOL)

    The trend in variation of complex stability constants with change in the mole fraction of the medium is explained on the basis of prevailing electrostatic and non-electrostatic forces. The species distribution as a function of pH at different compositions of TX100-water mixtures and plausible speciation equilibria are presented ...

  9. Synthesis, characterization, thermal behavior, and DNA-cleaving studies of cyano-bridged nickel(II)-copper(II) complexes of 4-(pyridin-2-ylazenyl)resorcinol.

    Science.gov (United States)

    Karipcin, Fatma; Ozmen, Ismail; Cülü, Burcin; Celikoğlu, Umut

    2011-10-01

    We present here the syntheses of a mononuclear Cu(II) complex and two polynuclear Cu(II)-Ni(II) complexes of the azenyl ligand, 4-(pyridin-2-ylazenyl)resorcinol (HL; 1). The reaction of HL (1) and copper(II) perchlorate with KCN gave a mononuclear complex [CuL(CN)] (4). Using 4, one pentanuclear complex, [{CuL(NC)}(4) Ni](ClO(4))(2) (5) and one trinuclear complex, [{CuL(CN)}(2) NiL]ClO(4) (6), were prepared and characterized by elemental analyses, magnetic susceptibility, molar conductance, IR, and thermal analysis. Stoichiometric and spectral results of the mononuclear Cu(II) complex indicated that the metal/ligand/CN ratio was 1 : 1 : 1, and the ligand behaved as a tridentate ligand forming neutral metal chelates through the pyridinyl and azenyl N-, and resorcinol O-atom. The interaction between the compounds (the ligand 1, its Ni(II) and Cu(II) complexes without CN, i.e., 2 and 3, and its complexes with CN, 4-6) and DNA has also been investigated by agarose gel electrophoresis. The pentanuclear Cu(4) Ni complex (5) with H(2) O(2) as a co-oxidant exhibited the strongest DNA-cleaving activity. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  10. Synthesis, spectroscopic characterization and in vitro antimicrobial studies of Schiff base ligand, H2L derived from glyoxalic acid and 1,8-diaminonaphthalene and its Co(II, Ni(II, Cu(II and Zn(II complexes

    Directory of Open Access Journals (Sweden)

    Saud I. Al-Resayes

    2016-05-01

    Full Text Available A novel Schiff base ligand, N,N′-bis (glyoxalicacidcarboxaldiimine-1,8-diaminonaphthalene [H2L] obtained by the condensation of glyoxalic acid and 1,8-diaminonaphthalene and its mononuclear complexes of type, [ML] [M = Co(II, Ni(II, Cu(II, Zn(II] have been synthesized and characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz., FT-IR, EPR, 1H NMR, FAB-Mass, UV–vis and magnetic moment data. A square planar geometry has been assigned on the basis of UV–vis and magnetic susceptibility around Co(II, Ni(II and Cu(II ions while conductivity data showed non electrolytic nature of all the complexes. The synthesized ligand, H2L and its complexes have been tested against Streptococcus mutans, Staphylococcus pyogenes, MRSA (Gram positive bacteria, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli (Gram negative bacteria, Candida albicans, Candida krusei, Candida parapsilosis and Candida neroformans and results suggested that Cu(II complex has significant antimicrobial activity.

  11. Synthesis, spectral elucidation, electrochemistry and DFT interpretation of manganese(II)-thioalkyl-arylazoimidazole complex

    Science.gov (United States)

    Nandi, Soumendranath; Das, Kuheli; Datta, Amitabha; Banerjee, Debashis; Roy, Suman; Mondal, Tapan Kumar; Mandal, Debashree; Nanda, Prasanta Kumar; Akitsu, Takashiro; Tanaka, Shinnosuke; Sinha, Chittaranjan

    2017-04-01

    One new Mn(II) thioalkyl-arylazoimidazole complex (1), [Mn(SRaaiNR/)2(SCN)2] (SRaaiNR/ = 1-alkyl-2-{(o-thioalkyl)phenylazo}imidazole and R = Me, R/ = Et) is afforded and systematically characterized by FT-IR, UV-Vis and EPR spectroscopy. The single crystal X-ray diffraction technique reveals that in complex 1, the central Mn atom possesses a tetrahedral environment of MnN4 sphere; coordinated by a pair of monodentate orientation of Nimidazolyl and NSCN atoms. Variable temperature magnetic moment confirms that in complex 1, there exists an antiferromagnetic coupling in tetrahedral symmetry. Cyclic voltammogram study of complex 1 evidenced the presence of a Mn(III)/Mn(II) redox response at 1.25 V alongwith azo reductions at -0.8 V. DFT computational using optimized geometry clearly explains the electronic and redox properties which is in accordance with the experimental evidence.

  12. Cu(II complexes with a pendant octaazamacrocycle and m-bonded aromatic carboxylates

    Directory of Open Access Journals (Sweden)

    DEJAN POLETI

    2002-10-01

    Full Text Available Three new cationic mixed-ligand Cu(II complexes with N,N’,N’’,N’’’-tetrakis(2-pyridylmethyl-1,4,8,11-tetraazacyclotetradecane (tpmc and bridging aromatic mono- or dicarboxylate ligands were prepared. Elemental analysis, conductometric and magnetic measurements, as well as electronic and IR spectroscopy were employed for their characteriization. It is proposed that the complexes [Cu2(C6H5COOtpmc](CIO43MeOH and [Cu2(Hphttpmc](CIO43H2O (H2pht = phthalic acid are binuclear with m-coordination of the carboxylate monoanions. The third complex, [Cu4ipht(tpmc2](CIO46NaClO42MeCN (H2ipht = isophthalic acid is one of the rare tetranuclear Cu(II-tpmc complexes with an aromatic dicarboxylate ion bridging two Cu2tpmc units. This was also confirmed by preliminary results of the determination of the crystal structure.

  13. From Synthesis to Biological Impact of Pd (II Complexes: Synthesis, Characterization, and Antimicrobial and Scavenging Activity

    Directory of Open Access Journals (Sweden)

    Nitin Kumar Sharma

    2016-01-01

    Full Text Available The Pd (II complexes with a series of halosubstituted benzylamine ligands (BLs have been synthesized and characterized with different spectroscopic technique such as FTIR, UV/Vis, LCMS, 1H, and 13C NMR. Their molecular sustainability in different solvents such as DMSO, DMSO : H2O, and DMSO : PBS at physiological condition (pH 7.2 was determined by UV/Vis spectrophotometer. The in vitro antibacterial and antifungal activities of the complexes were investigated against Gram-positive and Gram-negative microbes and two different fungi indicated their significant biological potential. Additionally, their antioxidant activity has been analyzed with DPPH• free radical through spectrophotometric method and the result inferred them as an antioxidant. The stronger antibacterial and antioxidant activities of the synthesized complexes suggested them as a stronger antimicrobial agent. Our study advances the biological importance of palladium (II amine complexes in the field of antimicrobial and antioxidant activities.

  14. Synthesis and characterization of transition metal 2,6-pyridinedicarboxylic acid derivatives, interactions of Cu(II) and Ni(II) complexes with DNA in vitro

    Science.gov (United States)

    Khan, Sadaf; Nami, Shahab A. A.; Siddiqi, K. S.; Husain, Eram; Naseem, Imrana

    2009-03-01

    Mononuclear complexes M(L)Cl 2 where M = Mn(II), Fe(II), Co(II), Ni(II) and Cu(II) and (L = N,N-diethylpiperazinyl,2,6-pyridinedicarboxylate), have been synthesized and characterized by elemental analysis, FT-IR, 1H NMR spectroscopy, UV-vis, magnetic moment, TGA/DSC, cyclic voltammetry and conductivity measurement data. The spectral data suggests that the dipicolinic acid acts as a bidentate ligand and is coordinated to the metal ion through the carboxylate oxygen. The cyclic voltammogram for Cu(L)Cl 2 complex was found to display two reversible Cu(II)/Cu(I) and Cu(II)/Cu(III) redox couple. The ligand exhibits a two-step thermolytic pattern while the complexes decompose in three stages respectively. An octahedral geometry has been proposed for both the complexes. The investigation of the interaction of the complexes with calf thymus DNA has been performed with absorption spectroscopy and fluorescence quenching experiments, which showed that the complexes are avid binders of calf thymus DNA. Also the interaction of the Cu(II) and Ni(II) complexes with plasmid DNA (pUC 19) was studied using agarose gel electrophoresis. The results revealed that these complexes can act as effective DNA cleaving agents resulting in the nicked form of DNA (pUC 19) under physiological conditions. The gel was run both in the absence and presence of an oxidizing agent (H 2O 2). The ligand and its complexes have also been screened against microbes in order to study their antibacterial action. The results revealed that the Cu(II) complex has activity comparable with the reference drugs gentamycin and flucanzole.

  15. Structural Investigation in Solution of a series of five-Coordinate Bisphosphinoaryl Ruthenium(II) Complexes

    NARCIS (Netherlands)

    Koten, G. van; Dani, P.; Kink, G. van

    2000-01-01

    The structure of the ruthenium(II) complexes [RuCl{C6H2(CH2PPh2)2-2,6-R-4}(PPh3)] [R = H (1), Ph (2) or Br (3)] was investigated in solution using two-dimensional NMR techniques (1H-1H-, 13C-1H- and 31P-1H-correlation NMR spectroscopy and 1H NOESY). The 1H and 13C NMR spectra of the complexes 1-3

  16. Synthesis and Characterization of the Adducts of Morpholinedithioccarbamate Complexes of Oxovanadium (IV, Nickel(II, and Copper(II with Piperidine and Morpholine

    Directory of Open Access Journals (Sweden)

    Mousami Sharma

    2012-01-01

    Full Text Available A series of 1:1 adducts of bis(morpholinedithiocarbamato complex of VO(IV, 1:1 and 1:2 adducts of bis(morpholinedithiocarbamato complexes of Ni(II and Cu(II with piperidine and morpholine have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibility, IR, UV-Vis, and TGA/DTA techniques. Analytical data reveals that VO(IV complex forms only 1:1 adducts with the formula [VO(morphdtc2L].H2O while Ni(II and Cu(II complexes form both 1:1 and 1:2 adducts with 1:1 adducts having general formula Ni(morphdtc2.L and Cu(morphdtc2.L and 1:2 adducts having general formula Ni(morphdtc2.L2 and Cu(morphdtc2.L2 (morphdtc = morpholinedithiocarbamate, L = morpholine and piperidine. Antifungal activity of some complexes has been carried out against the fungal strain Fusarium oxysporium. Thermal studies indicate a continuous weight loss. A square pyramidal geometry has been proposed for the 1:1 adducts of Ni(II and Cu(II complexes while an octahedral geometry has been proposed for the 1:1 adducts of VO(IV and for the 1:2 adducts of Ni(II and Cu(II complexes.

  17. Bioinspired manganese(II) complexes with a clickable ligand for immobilisation on a solid support.

    Science.gov (United States)

    Chaignon, Jérémy; Stiriba, Salah-Eddine; Lloret, Francisco; Yuste, Consuelo; Pilet, Guillaume; Bonneviot, Laurent; Albela, Belén; Castro, Isabel

    2014-07-07

    Clickable ligands like N,N'-bis((pyridin-2-yl)methyl)prop-2-yn-1-amine (L(1)) and N-((1-methyl-1H-imidazol-2-yl)methyl)-N-(pyridin-2-ylmethyl)prop-2-yn-1-amine (L(2)) have been used to synthesise a series of manganese(ii) complexes for grafting onto appropriate solid supports. These ligands mimic the 2-His-1-carboxylate facial chelation present in the active site of the manganese-dependent dioxygenase (MndD), while the alkyne side function allows grafting of the ligand onto an azido-functionalised support using "click chemistry" methodologies. Such synthetic analogues of the MndD crystallise in the solid state as double halide or pseudohalide-bridged dinuclear manganese(ii) complexes of the general formula [Mn2(μ-X)2X2L2] [L = L(1) with X = Cl (), Br (), and N3 (); L = L(2) with X = N3 ()]. Complexes are characterised by a weak magnetic exchange interaction between the two high-spin Mn(II) ions through the two X(-) bridges (J in the range of -0.059 to +5.30 cm(-1), H = -J·SMn1·SMn2 with SMn1 = SMn2 = 5/2). A new magneto-structural correlation of superexchange bis(μ1,1-azido)dimanganese(ii) complexes has been proposed using both structural parameters, the Mn-N-Mn bridging angle and the Mn-Nazido distance. In MeOH-EtOH solution the dimeric species are present together with few percents of mononuclear manganese(ii) complexes as evidenced by electron paramagnetic resonance (EPR) spectroscopy. Grafting the complexes onto mesoporous silica of MCM-41 type stabilises both dimers and monomers in the nanopores of the solid.

  18. Environmental pH and the requirement for the extrinsic proteins of Photosystem II in the function of cyanobacterial photosynthesis

    Directory of Open Access Journals (Sweden)

    Jaz N Morris

    2016-08-01

    Full Text Available In one of the final stages of cyanobacterial Photosystem II (PS II assembly, binding of up to four extrinsic proteins to PS II stabilizes the oxygen-evolving complex (OEC. Growth of cyanobacterial mutants deficient in certain combinations of these thylakoid-lumen-associated polypeptides is sensitive to changes in environmental pH, despite the physical separation of the membrane-embedded PS II complex from the external environment. In this perspective, we discuss the effect of environmental pH on OEC function and photoautotrophic growth in cyanobacteria, with reference to pH-sensitive PS II mutants lacking extrinsic proteins. We consider the possibilities that, compared to pH 10.0, pH 7.5 increases susceptibility to PS II-generated reactive oxygen species (ROS, causing photoinhibition and reducing PS II assembly in some mutants and that perturbations to channels in the lumenal regions of PS II might alter the accessibility of water to the active site, and egress of oxygen and protons to the thylakoid lumen. Reduced levels of PS II in these mutants and reduced OEC activity arising from the disruption of substrate/product channels could reduce the trans-thylakoid pH gradient (ΔpH, leading to the impairement of photosynthesis. Growth of some PS II mutants at pH 7.5 can be rescued by elevating CO2 levels, suggesting that the pH-sensitive phenotype might primarily be an indirect result of back-pressure in the electron transport chain that results in heightened production of ROS by the impaired photosystem.

  19. Antibacterial and antifungal activity of zinc(II complexes with some 2-methylbenzimidazole derivatives

    Directory of Open Access Journals (Sweden)

    Podunavac-Kuzmanović Sanja O.

    2005-01-01

    Full Text Available Zinc(II chloride reacts with 2-methylbenzimidazole derivatives to give complexes of the formula ZnL2Cl2-nH2O, where L=2-methylbenzimidazole l-benzyl-2-methylbenzimida-zole and l-(4-methylbenzyl-2-methylbenzimidazole n=0, 0.5 or 1. All the ligands and their zinc(II complexes were evaluated for their in vitro antimicrobial activity against Pseudomonas aeruginosa Bacillus sp., Staphylococcus aureus, Sarcina lutea and Candida pseudotropicalis. It was found that the majority of the investigated compounds displayed in vitro antimicrobial activity against very persistent microorganisms, except for the starting ligand, 2-methylbenzimidazole and its zinc(II complex which were active only against gram-negative bacteria. None of the compounds was significantly effective against Candida pseudotropicalis, except for l-(4-methylbenzyl-2-methylbenzimidazoleandits complex, which very slightly or slightly inhibited the yeast growth. The minimum inhibitory concentration (MIC was determined for all the ligands and their complexes. The effect of ligand and complex structure on the antimicrobial activity was discussed.

  20. TDDFT study on recognition mechanism for the oxygen sensing of the cyclometalated platinum (II) complex

    Science.gov (United States)

    Tong, Huan; Zhao, Zhengyan; Li, Guanglan; Gao, Liguo; Zhao, Ningjiu; Li, Peng; Jia, Yan; Zhou, Chenyang; Zhang, Mingzhen; Wang, Yong; Hao, Ce; Tang, Xiaoying

    2017-08-01

    The influence of oxygen molecule on the luminescent properties of a cyclometalated Pt(II) complex Lxp1, was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. Analysis of frontier molecular orbitals and electronic configuration indicated that the highest-occupied molecular orbital of the Lxp1 has a significant mixture of metal Pt (d) as well as 2-phenylpyridine and acetyl acetone(π). The lowest-unoccupied orbital of the Lxp1 primarily locates on π* of 2-phenylpyridineligands. The emission mechanism of the cyclometalated Pt(II) complex Lxp1 is assigned to the mixing of ligand-to-metal charge transfer and ligand-to-ligand charge transfer. The emission mechanism of the Lxp1-O2 complex can be attributed to the charge transfer from the oxygen molecule to the luminescent material Lxp1. Our study showed that intermolecular hydrogen bonding between the Lxp1 and oxygen molecule was strengthened by the calculation of electronic excitation, leading to a luminescence-decreasing phenomenon. The calculation of the radiative and non-radiative decay rate constants of the Lxp1 and the Lxp1-O2 complex demonstrates that the phosphorescence from T1-S0 of the Lxp1 would alter to the internal conversion from T1-T0 of the Lxp1-O2 complex. This alteration further explains the luminescence quenching phenomenon of the cyclometalated Pt(II) complex Lxp1 after interacting with oxygen molecule.

  1. Catecholase activity of a mu-hydroxodicopper(II) macrocyclic complex: structures, intermediates and reaction mechanism.

    Science.gov (United States)

    Koval, Iryna A; Belle, Catherine; Selmeczi, Katalin; Philouze, Christian; Saint-Aman, Eric; Schuitema, Anna Maria; Gamez, Patrick; Pierre, Jean-Louis; Reedijk, Jan

    2005-11-01

    The monohydroxo-bridged dicopper(II) complex (1), its reduced dicopper(I) analogue (2) and the trans-mu-1,2-peroxo-dicopper(II) adduct (3) with the macrocyclic N-donor ligand [22]py4pz (9,22-bis(pyridin-2'-ylmethyl)-1,4,9,14,17,22,27,28,29,30- decaazapentacyclo -[22.2.1(14,7).1(11,14).1(17,20)]triacontane-5,7(28),11(29),12,18,20(30), 24(27),25-octaene), have been prepared and characterized, including a 3D structure of 1 and 2. These compounds represent models of the three states of the catechol oxidase active site: met, deoxy (reduced) and oxy. The dicopper(II) complex 1 catalyzes the oxidation of catechol model substrates in aerobic conditions, while in the absence of dioxygen a stoichiometric oxidation takes place, leading to the formation of quinone and the respective dicopper(I) complex. The catalytic reaction follows a Michaelis-Menten behavior. The dicopper(I) complex binds molecular dioxygen at low temperature, forming a trans-mu-1,2-peroxo-dicopper adduct, which was characterized by UV-Vis and resonance Raman spectroscopy and electrochemically. This peroxo complex stoichiometrically oxidizes a second molecule of catechol in the absence of dioxygen. A catalytic mechanism of catechol oxidation by 1 has been proposed, and its relevance to the mechanisms earlier proposed for the natural enzyme and other copper complexes is discussed.

  2. One-dimensional Co(II)/Ni(II) complexes of 2-hydroxyisophthalate: Structures and magnetic properties

    Science.gov (United States)

    Wang, Kai; Zou, Hua-Hong; Chen, Zi-Lu; Zhang, Zhong; Sun, Wei-Yin; Liang, Fu-Pei

    2015-03-01

    The solvothermal reactions of 2-hydroxyisophthalic acid (H3ipO) with M(NO3)2•6H2O (M=Co, Ni) afforded two complexes [Co2(HipO)2(Py)2(H2O)2] (1) and [Ni(HipO)(Py)H2O] (2) (Py=pyridine). They exhibit similar zig-zag chain structures with the adjacent two metal centers connected by a anti-syn bridging carboxylate group from the HipO2- ligand. The magnetic measurements reveal the dominant antiferromagnetic interactions and spin-canting in 1 while ferromagnetic interactions in 2. Both of them exhibit magnetocaloric effect (MCE) with the resulting entropy changes (-ΔSm) of 12.51 J kg-1 K-1 when ΔH=50 kOe at 3 K for 1 and 11.01 J kg-1 K-1 when ΔH=50 kOe at 3 K for 2, representing the rare examples of one-dimensional complexes with MCE.

  3. RutheniumII(η6-arene Complexes of Thiourea Derivatives: Synthesis, Characterization and Urease Inhibition

    Directory of Open Access Journals (Sweden)

    Muhammad Hanif

    2014-06-01

    Full Text Available RuII(arene complexes have emerged as a versatile class of compounds to design metallodrugs as potential treatment for a wide range of diseases including cancer and malaria. They feature modes of action that involve classic DNA binding like platinum anticancer drugs, may covalent binding to proteins, or multimodal biological activity. Herein, we report the synthesis and urease inhibition activity of RuII(arene complexes of the general formula [RuII(η6-p-cymene(LCl2] and [RuII(η6-p-cymene(PPh3(LCl]PF6 with S-donor systems (L based on heterocyclic thiourea derivatives. The compounds were characterized by 1H-, 13C{1H}- and 31P{1H}-NMR spectroscopy, as well as elemental analysis. The crystal structure of [chlorido(η6-p-cymene(imidazolidine-2-thione(triphenylphosphineruthenium(II] hexafluorophosphate 11 was determined by X-ray diffraction analysis. A signal in the range 175–183 ppm in the 13C{1H}-NMR spectrum indicates the presence of a thione rather than a thiolate. This observation was also confirmed in the solid state by X-ray diffraction analysis of 11 which shows a C=S bond length of 1.720 Å. The compounds were tested for urease inhibitory activity and the thiourea-derived ligands exhibited moderate activity, whereas their corresponding Ru(arene complexes were not active.

  4. Supramolecular complexes of Co(II), Ni(II) and Zn(II) p-hydroxybenzoates with caffeine: Synthesis, spectral characterization and crystal structure

    Science.gov (United States)

    Taşdemir, Erdal; Özbek, Füreya Elif; Sertçelik, Mustafa; Hökelek, Tuncer; Çelik, Raziye Çatak; Necefoğlu, Hacali

    2016-09-01

    Three novel complexes Co(II), Ni(II) and Zn(II) containing p-hydroxybenzoates and caffeine ligands were synthesized and characterized by elemental analysis, FT-IR and UV-vis Spectroscopy, molar conductivity and single crystal X-ray diffraction methods. The thermal properties of the synthesized complexes were investigated by TGA/DTA. The general formula of the complexes is [M(HOC6H4COO)2(H2O)4]·2(C8H10N4O2)·8H2O (where: M: Co, Ni and Zn). The IR studies showed that carboxylate groups of p-hydroxybenzoate ligands have monodentate coordination mode. The M2+ ions are octahedrally coordinated by two p-hydroxybenzoate ligands, four water molecules leading to an overall MO6 coordination environment. The medium-strength hydrogen bondings involving the uncoordinated caffeine ligands and water molecules, coordinated and uncoordinated water molecules and p-hydroxybenzoate ligands lead to three-dimensional supramolecular networks in the crystal structures.

  5. Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment

    Science.gov (United States)

    El-Baradie, K.; El-Sharkawy, R.; El-Ghamry, H.; Sakai, K.

    2014-03-01

    The azodye ligand (HL1) was synthesized from the coupling of sulfaguanidine diazonium salt with 2,4-dihydroxy-benzaldehyde while the two ligands, HL2 and HL3, were prepared by the coupling of sulfadiazine diazonium salt with salicylaldehyde (HL2) and 2,4-dihydroxy-benzaldehyde (HL3). The prepared ligands were characterized by elemental analysis, IR, 1H NMR and mass spectra. Cu(II), Co(II) and Ni(II) complexes of the prepared ligands have been synthesized and characterized by various spectroscopic techniques like IR, UV-Visible as well as magnetic and thermal (TG and DTA) measurements. It was found that all the ligands behave as a monobasic bidentate which coordinated to the metal center through the azo nitrogen and α-hydroxy oxygen atoms in the case of HL1 and HL3. HL2 coordinated to the metal center through sulfonamide oxygen and pyrimidine nitrogen. The applications of the prepared complexes in the oxidative degradation of indigo carmine dye exhibited good catalytic activity in the presence of H2O2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. The degradation reaction involved the catalytic action of the azo-dye complexes toward H2O2 decomposition, which can lead to the generation of HOrad radicals as a highly efficient oxidant attacking the target dye. The detailed kinetic studies and the mechanism of these catalytic reactions are under consideration in our group.

  6. Chemical speciation of L-glutamine complexes with Co(II, Ni(II and Cu(II in cationic micellar medium

    Directory of Open Access Journals (Sweden)

    Gandham Hima Bindu

    2012-12-01

    Full Text Available The impact of cationic micelles on the protonation equilibria of L-glutamine and chemical speciation of its complexes with Co(II, Ni(II and Cu(II have been studied by monitoring hydrogen ion concentration pH metrically at 303 K and at an ionic strength of 0.16 M. The protonation constants and binary stability constants have been calculated with the computer program MINIQUAD75. The best fit chemical models are selected based on standard deviations in the model parameters and residual analysis using crystallographic R-factor and sum of squares of residuals in all mass-balance equations. The trend in the variation of stability constants of the complexes with mole fraction of the surfactant is attributed to the compartmentalization of complexation equilibria. Distribution of species and effect of influential parameters on chemical speciation have also been presented.DOI: http://dx.doi.org/10.4314/bcse.v26i3.7

  7. Monoprotic Tetradentate N(3)O-Donor Ligands and Their Cu(II) and Ni(II) Complexes.

    Science.gov (United States)

    Luo, Hongyan; Lo, Jem-Mau; Fanwick, Phillip E.; Stowell, Joseph G.; Green, Mark A.

    1999-05-03

    A convenient four-step procedure was developed to prepare the novel monoprotic tetradentate ligands N-(2-hydroxy)benzyl-N-methyl-N'-(2-pyridyl)methyl-1,3-propanediamine (Hpamap) and N-(2-hydroxy)benzyl-N'-methyl-N'-(2-pyridyl)methyl-1,3-propanediamine (Hpmaap), which provide an N(3)O metal coordination sphere. A mononuclear copper(II) complex, [Cu(pamap)Cl] (A), was obtained by reaction of Hpamap with CuCl(2).2H(2)O. The binuclear copper(II) complexes [Cu(pamap)](2)(BF(4))(2) (B) and [Cu(pmaap)](2)(BF(4))(2) (C) were obtained when these ligands were reacted with Cu(II) in the presence of the noncoordinating BF(4)(-) anion. Reaction of nickel(II) with the Hpamap ligand generated the binuclear Ni(II) complex [Ni(2)(pamap)(2)(NO(3))]NO(3) (D). The crystal of A (C(17)H(22)ClCuN(3)O) is orthorhombic Pbca (No. 61), a = 11.837(4) Å, b = 15.648(5) Å, c = 11.002(11) Å, Z = 8; that of B (C(34)H(44)B(2)Cu(2)F(8)N(6)O(2)) is triclinic P&onemacr; (No. 2), a = 9.147(0) Å, b = 10.375(0) Å, c = 10.535(1) Å, alpha = 107.20(0) degrees, beta = 91.19(0) degrees, gamma = 105.05(0) degrees, Z = 1; that of C (C(34)H(44)B(2)Cu(2)F(8)N(6)O(2)) is monoclinic P2(1)/c (No. 14), a = 9.158(2) Å, b = 10.714(2) Å, c = 19.085(4) Å, beta = 90.58(2) degrees, Z = 4; and that of D (C(34)H(44)N(8)NiO(8)) is monoclinic C2/c (No. 15), a = 13.849(0) Å, b = 13.609(0) Å, c = 19.558(1) Å, beta = 92.34 (0) degrees, Z = 4. The copper atoms of all three complexes are five-coordinate in the solid state, assuming the geometry of a distorted square pyramid with the deprotonated tetradentate ligand in the basal plane. The mononuclear complex A has a chloride ligand in the axial position, while each copper center in the binuclear complexes B and C has, in the axial position, a bridging phenolate O donor from the other unit of the dimer. Each nickel center in the binuclear complex D is six-coordinate, with the pseudo-octahedron formed by a deprotonated tetradentate ligand, a bridging nitrato oxygen atom

  8. Interaction of drug based copper(II) complexes with Herring Sperm DNA and their biological activities

    Science.gov (United States)

    Patel, Mohan N.; Patel, Chintan R.; Joshi, Hardik N.

    2012-11-01

    Square pyramidal Cu(II) complexes with NS donor ligand and ciprofloxacin have been synthesized and characterized using analytical and spectral techniques. The synthesized complexes have been tested for their antimicrobial activity using double dilution technique in terms of minimum inhibitory concentration (MIC) and colony forming unit (CFU). The DNA binding ability of the complexes with Sperm Herring DNA has been performed using absorption titration and viscosity measurement. The nuclease activity of complexes with plasmid DNA (pUC19) has been carried out using agarose gel electrophoresis technique. Synthesized complexes have been tested for their SOD mimic activity using NBT/NADH/PMS system. The cytotoxic properties of metal complexes have been evaluated using brine shrimp lethality bioassay.

  9. Effect of substituent of terpyridines on the DNA-interaction of polypyridyl ruthenium(II) complexes

    Science.gov (United States)

    Patel, Mohan N.; Gandhi, Deepen S.; Parmar, Pradhuman A.

    2011-12-01

    An octahedral complexes of ruthenium with 2,9-dimethyl-1,10-phenanthroline (dmphen) and substituted terpyridine have been synthesized. The Ru II complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1H NMR and FAB mass spectra. The binding strength and mode of interaction of the complexes with Herring Sperm DNA has been investigated using absorption titration and viscosity measurement studies. Results suggest that the substituent on terpyridine ligand affects the binding mode and binding ability of the complexes. Effect of time and ionic strength on DNA cleavage ability of complex has also been studied by gel electrophoresis. Results suggest that more than 200 mM concentration of NaCl decreases the cleavage ability of complex.

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

    Science.gov (United States)

    Roy, Partha; Manassero, Mario

    2010-02-14

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

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

    Science.gov (United States)

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

    2015-02-01

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

  12. Microwave assisted synthesis, spectral, magnetic and bioevolution of few Mn (II)-amide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Gaurav [Department of Chemistry, Govt. Engineering College, Bikaner (India); Verma, K. K.; Gudesaria, D. D.; Bhojak, N., E-mail: drbhojak@rediffmail.com [GCRC, Department of Chemistry, Govt Dungar College, Bikaner-334003, Rajasthan (India)

    2016-05-06

    The importance and versatility of amide group containing ligands have promoted the selection of this class of ligands and their complexes for the study. The present work describes the synthesis, spectral and biological investigations on the complexes of amides derived from heterocyclic amines with Mn (II) ions. Four ligands derived 2-aminopyridine and their complexes with Mn (II) have been synthesized. A method for the synthesis of complexes has been developed by the use of microwave irradiation which is in agreement to Green chemistry approach. The complexes have been characterized on the basis of elemental analysis, infrared, electronic, ESR spectra and magnetic susceptibility studies. The diffuse reflectance spectrum of the complexes show bands in the region 20,000 cm{sup −1} to 26,000 cm{sup −1} assignable to {sup 6}A{sub 1g} → {sup 4}T{sub 2g} and {sup 6}A{sub 1g} → {sup 4}E{sub 1g} transitions. These are also typical of tetrahedral environment around the manganese. The magnetic moment (5.80 BM) of the complex indicates high spin tetrahedral environment. The microwave method of synthesis of complexes have been found easier, convenient and ecofriendly. Antimicrobial activities of compounds were also carried out against bacteria and fungi. Further minimal inhibitory concentration (MIC) was also determined for each compound.

  13. Microwave assisted synthesis, spectral, magnetic and bioevolution of few Mn (II)-amide complexes

    Science.gov (United States)

    Joshi, Gaurav; Verma, K. K.; Gudesaria, D. D.; Bhojak, N.

    2016-05-01

    The importance and versatility of amide group containing ligands have promoted the selection of this class of ligands and their complexes for the study. The present work describes the synthesis, spectral and biological investigations on the complexes of amides derived from heterocyclic amines with Mn (II) ions. Four ligands derived 2-aminopyridine and their complexes with Mn (II) have been synthesized. A method for the synthesis of complexes has been developed by the use of microwave irradiation which is in agreement to Green chemistry approach. The complexes have been characterized on the basis of elemental analysis, infrared, electronic, ESR spectra and magnetic susceptibility studies. The diffuse reflectance spectrum of the complexes show bands in the region 20,000 cm-1 to 26,000 cm-1 assignable to 6A1g → 4T2g and 6A1g → 4E1g transitions. These are also typical of tetrahedral environment around the manganese. The magnetic moment (5.80 BM) of the complex indicates high spin tetrahedral environment. The microwave method of synthesis of complexes have been found easier, convenient and ecofriendly. Antimicrobial activities of compounds were also carried out against bacteria and fungi. Further minimal inhibitory concentration (MIC) was also determined for each compound.

  14. A Chromium(II) Tetracarbene Complex Allows Unprecedented Oxidative Group Transfer.

    Science.gov (United States)

    Elpitiya, Gaya R; Malbrecht, Brian J; Jenkins, David M

    2017-11-20

    Multiple distinct oxidative group transfer reactions to low valent chromium were examined. Six new chromium complexes were prepared from a highly electronically unsaturated Cr(II) square planar complex that was supported by a macrocyclic tetracarbene ligand. This complex's reactivity with Me3NO and disparate azides was investigated. The reaction with Me3NO generated a highly stable Cr(IV)-oxo complex. Less bulky organic azides such as p-tolyl and n-octyl azides gave rise to metallotetrazenes, while more sterically demanding mesityl and adamantyl azides generated Cr(IV)-imido complexes. The reaction of the square planar Cr(II) complex with TMS-azide yielded the first linearly bridging nitrido chromium species. Reductive group transfer was explored for a Cr(IV)-imido complex, and organic products, such as aziridines, were formed after addition. Cr(IV) imidos and oxos are quite rare, while tetrazenes and bridging nitridos are virtually unknown. This is the most detailed study on oxidative group transfer reactions using chromium based complexes on a single auxiliary ligand to date.

  15. Catalytic Oxygen Evolution by a Bioinorganic Model of the Photosystem II Oxygen-Evolving Complex

    Science.gov (United States)

    Howard, Derrick L.; Tinoco, Arthur D.; Brudvig, Gary W.; Vrettos, John S.; Allen, Bertha Connie

    2005-01-01

    Bioinorganic models of the manganese Mn4 cluster are important not only as aids in understanding the structure and function of the oxygen-evolving complex (OEC), but also in developing artificial water-oxidation catalysts. The mechanism of water oxidation by photosystem II (PSII) is thought to involve the formation of a high-valent terminal Mn-oxo…

  16. CD1 and major histocompatibility complex II molecules follow a different course during dendritic cell maturation

    NARCIS (Netherlands)

    van der Wel, Nicole N.; Sugita, Masahiko; Fluitsma, Donna M.; Cao, Xaiochun; Schreibelt, Gerty; Brenner, Michael B.; Peters, Peter J.

    2003-01-01

    The maturation of dendritic cells is accompanied by the redistribution of major histocompatibility complex (MHC) class II molecules from the lysosomal MHC class IT compartment to the plasma membrane to mediate presentation of peptide antigens. Besides MHC molecules, dendritic cells also express CD1

  17. O2 Activation and Double CH Oxidation by a Mononuclear Manganese(II) Complex

    NARCIS (Netherlands)

    Deville, Claire; Padamati, Sandeep K; Sundberg, Jonas; McKee, Vickie; Browne, Wesley R; McKenzie, Christine J

    2015-01-01

    A Mn(II) complex, [Mn(dpeo)2 ](2+) (dpeo=1,2-di(pyridin-2-yl)ethanone oxime), activates O2 , with ensuing stepwise oxidation of the methylene group in the ligands providing an alkoxide and ultimately a ketone group. X-ray crystal-structure analysis of an intermediate homoleptic alkoxide Mn(III)

  18. CATALYTIC ENANTIOSELECTIVE CONJUGATE ADDITION OF DIETHYLZINC USING NI(II) DAIB COMPLEXES

    NARCIS (Netherlands)

    JANSEN, JFGA; FERINGA, BL

    The conjugate addition of diethylzinc to chalcone, catalyzed by a NiII complex of the chiral amino-alcohol (-)-DAIB, resulted in the formation of (R)-1,3-diphenyl-penta-1-one with enantiomeric excess up to 85%.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  20. Four-site cooperative spin crossover in a mononuclear FeII complex

    DEFF Research Database (Denmark)

    Lennartson, Anders; Bond, Andrew D; Piligkos, Stergios

    2012-01-01

    Round and round: A mononuclear Fe(II) complex (see picture) with an N(4)S(2) coordination set has been characterized in four polymorphic forms. Two of the polymorphs display four-site cooperative spin crossover (SCO), shown conclusively by the crystal structure of a fully ordered 1:3 high-spin/lo...

  1. High turnover catalysis of water oxidation by Mn(II) complexes of monoanionic pentadentate ligands

    DEFF Research Database (Denmark)

    Seidler-Egdal, Rune Kirk; Nielsen, Anne; Bond, Andrew

    2011-01-01

    Capillary electrophoresis (CE) and electrospray ionisation (ESI) mass spectra of aqueous solutions of manganese(II) complexes of the monoanions of the pentadentate ligands N-methyl-N'-carboxymethyl-N,N'-bis(2-pyridylmethyl)ethane-1,2-diamine (mcbpen(-)) and N-benzyl-N'-carboxymethyl-N,N'-bis(2-py...

  2. Highly stereoselective cyclopropanation of diazo Weinreb amides catalyzed by chiral Ru(ii)-Amm-Pheox complexes.

    Science.gov (United States)

    Chanthamath, Soda; Mandour, Hamada S A; Tong, Thu Minh Thi; Shibatomi, Kazutaka; Iwasa, Seiji

    2016-06-14

    The first highly stereoselective cyclopropanation of diazo Weinreb amides with olefins was accomplished using chiral Ru(ii)-Amm-Pheox complex to give the corresponding chiral cyclopropyl Weinreb amides in high yields (up to 99%) with excellent diastereoselectivities (up to 99 : 1 dr) and enantioselectivities (up to 96% ee).

  3. Thermodynamic characteristics of the formation of complexes of nickel(II) with L-homoserine

    Science.gov (United States)

    Gridchin, S. N.

    2016-12-01

    The formation of complexes of nickel(II) with L-homoserine at 298.15 K and ionic strengths I = 0.5, 1.0, and 1.5 (KNO3) are investigated by potentiometry and calorimetry. Standard characteristics of studied equilibria (log K°, Δr G°, Δr H°, and Δr S°) are determined.

  4. Nickel (II) complexes of N 2 S 2 donor set ligand and halide ...

    Indian Academy of Sciences (India)

    The complexes were characterized by physicochemical and spectroscopic methods along with detailed structural characterization of 1,2 and 3 by single crystal X-ray diffraction analyses. The structural study showed that the nickel(II) ion has a distorted octahedral geometry being chelated by the tetradentate N2S2 ligand ...

  5. Nickel(II) complexes of N2S2 donor set ligand and halide ...

    Indian Academy of Sciences (India)

    J. Chem. Sci. Vol. 127, No. 11, November 2015, pp. 1883–1893. c Indian Academy of Sciences. DOI 10.1007/s12039-015-0962-3. Nickel(II) complexes of ... ized by physicochemical and spectroscopic methods along with detailed structural characterization of 1,2 and ... we report an account of coordination chemistry of.

  6. Probing the picosecond kinetics of the photosystem II core complex in vivo

    NARCIS (Netherlands)

    Tian, L.; Farooq, S.; Amerongen, van H.

    2013-01-01

    Photosystems I (PSI) and II (PSII) are two major pigment–protein complexes of photosynthetic organisms that function in series to convert sunlight energy into chemical energy. We have studied the picosecond fluorescence behaviour of the core of both photosystems in vivo by using two Synechocystis

  7. Photoenhanced Oxidative DNA Cleavage with Non-Heme Iron(II) Complexes

    NARCIS (Netherlands)

    Li, Qian; Browne, Wesley R.; Roelfes, Gerard

    2010-01-01

    The DNA cleavage activity of iron(II) complexes of a series of monotopic pentadentate N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine (N4Py)-derived ligands (1-5) was investigated under laser irradiation at 473, 400.8, and 355 nm in the absence of a reducing agent and compared to that under

  8. Light-harvesting and structural organization of Photosystem II: From individual complexes to thylakoid membrane

    NARCIS (Netherlands)

    Croce, R.; van Amerongen, H.

    2011-01-01

    Photosystem II (PSII) is responsible for the water oxidation in photosynthesis and it consists of many proteins and pigment-protein complexes in a variable composition, depending on environmental conditions. Sunlight-induced charge separation lies at the basis of the photochemical reactions and it

  9. Light-harvesting and structuralorganization ofphotosystem II: from individual complexes to thylakoid membrane

    NARCIS (Netherlands)

    Croce, R.; Amerongen, van H.

    2011-01-01

    Photosystem II (PSII) is responsible for the water oxidation in photosynthesis and it consists of many proteins and pigment-protein complexes in a variable composition, depending on environmental conditions. Sunlight-induced charge separation lies at the basis of the photochemical reactions and it

  10. Stoichiometry of Zn(II)-heparin-glycine complex, determined using data from elemental and thermal analysis

    Science.gov (United States)

    Feofanova, M. A.; Skobin, M. I.; Kryukov, T. V.; Alekseev, V. G.; Ryasenskii, S. S.

    2017-10-01

    Ternary polymer Zn(II)-heparin-glycine complex with the composition {Na3[ZnHepGly]·H2O} n , where Hep4- is the monomer chain of a heparin polyanion and Gly- is the chain of a glycine anion, is isolated in a solid state from a water solution, and is characterized via elemental and thermal analysis.

  11. Occupancy and Functional Architecture of the Pigment Binding Sites of Photosystem II Antenna Complex Lhcb5

    NARCIS (Netherlands)

    Ballottari, Matteo; Mozzo, Milena; Croce, Roberta; Morosinotto, Tomas; Bassi, Roberto

    2009-01-01

    Lhcb5 is an antenna protein that is highly conserved in plants and green algae. It is part of the inner layer of photosystem II antenna system retained in high light acclimated plants. To study the structure-function relation and the role of individual pigments in this complex, we (i) "knocked out"

  12. Pigment binding sites occupancy and functional architecture of the Photosystem II antenna complex Lhcb5

    NARCIS (Netherlands)

    Ballottari, M.; Mozzo, M.; Croce, R.; Morosinotto, T.; Bassi, R.

    2009-01-01

    Lhcb5 is an antenna protein that is highly conserved in plants and green algae. It is part of the inner layer of photosystem II antenna system retained in high light acclimated plants. To study the structure-function relation and the role of individual pigments in this complex, we (i) "knocked out"

  13. Anaerobic DNA cleavage in red light by dicopper(II) complexes on ...

    Indian Academy of Sciences (India)

    Administrator

    *For correspondence. Anaerobic DNA cleavage in red light by dicopper(II) complexes on disulphide bond activation. DEBOJYOTI LAHIRI a. , RITANKAR MAJUMDAR b. , ASHIS K PATRA a and. AKHIL R CHAKRAVARTY a,. *. aDepartment of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012.

  14. Ring-opening Metathesis Polymerization of Norbornene Catalyzed by Ru(II)-Vinylidene Complex

    NARCIS (Netherlands)

    Koten, G. van; Rio, I. del

    1999-01-01

    Highly selective ring opening metathesis polymerization (ROMP) of norbornene can be achieved using a new Ru(II)-vinylidene complex as catalyst precursor. The polymerization reaction proceeds in 1, 2-dichloroethane at 80 }o{C in absence of co-catalysts with high turnover frequencies. The molecular

  15. Mononuclear Fe(II)-N4Py complexes in oxidative DNA cleavage : structure, activity and mechanism

    NARCIS (Netherlands)

    Li, Qian; Berg, Tieme A. van den; Roelfes, Gerard; Feringa, Bernard

    2010-01-01

    A series of monotopic N4Py (N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) derived ligands have been prepared and evaluated in the iron catalyzed oxidative cleavage of pUC18 DNA, in the presence and absence of external reducing agent DTT. The mononuclear iron(II) complexes induce efficient

  16. N-donor functionalized N-heterocyclic carbene nickel(II) complexes in the Kumada coupling

    NARCIS (Netherlands)

    Berding, J.; van Dijkman, T.F.; Lutz, M.; Spek, A.L.; Bouwman, E.

    2009-01-01

    The synthesis and characterization of novel nickel(II) complexes bearing two bidentate N-heterocyclic carbene ligands functionalized with anionic N-donor moieties are described. Two different N-donor groups are employed, namely amido and benzimidazolato moieties. The solid-state structures of three

  17. Mesogenic copper (II) complexes with [1, 2, 3]-triazole-based ...

    Indian Academy of Sciences (India)

    The first mesogenic Cu(II) complex with [1,2,3]-triazole-based bidentate Schiff bases with flexible terminal alkyl chain, CnH2n+1 (even parity of n = 10-18) has been successfully synthesized. The heterocyclic triazole core was introduced into the target compound through the click reaction between azidoalkane and propargyl ...

  18. Benzyl anion abstraction from a (beta-diiminato)Fe(II) benzyl complex

    NARCIS (Netherlands)

    Sciarone, T.J.J.; Meetsma, A.; Hessen, B.; Teuben, J.H; Hesssen, B.

    2002-01-01

    The 3-coordinate 12 VE iron(II) benzyl complex [(nacnac)Fe(CH2Ph)] reacts with B(C6F5)(3) to yield a paramagnetic contact ion pair with an eta(2)-(o,m)-[PhCH2B(C6F5)(3)] anion, which was characterised by X-ray diffraction.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  20. One-Pot Synthesis of Cu(II Complex with Partially Oxidized TTF Moieties

    Directory of Open Access Journals (Sweden)

    Hiroki Oshio

    2012-07-01

    Full Text Available The one-pot synthesis of a Cu(II complex with partially oxidized tetrathiafulvalene (TTF moieties in its capping MT-Hsae-TTF ligands, [CuII(MT-sae-TTF2] [CuICl2] was realized by the simultaneous occurrence of Cu(II complexation and CuIICl2 mediated oxidation of TTF moieties. The crystal structure was composed of one-dimensional columns formed by partially oxidized TTF moieties and thus the cation radical salt showed relatively high electrical conductivity. Tight binding band structure calculations indicated the existence of a Peierls gap due to the tetramerization of the TTF moieties in the one-dimensional stacking column at room temperature, which is consistent with the semiconducting behavior of this salt.

  1. Spectrophotometric Determination of Metoprolol Tartrate in Pharmaceutical Dosage Forms on Complex Formation with Cu(II

    Directory of Open Access Journals (Sweden)

    Mustafa Cesme

    2011-06-01

    Full Text Available A new, simple, sensitive and accurate spectrophotometric method has been developed for the assay of metoprolol tartrate (MPT, which is based on the complexation of drug with copper(II [Cu(II] at pH 6.0, using Britton-Robinson buffer solution, to produce a blue adduct. The latter has a maximum absorbance at 675 nm and obeys Beer’s law within the concentration range 8.5-70 mg/mL. Regression analysis of the calibration data showed a good correlation coefficient (r = 0.998 with a limit of detection of 5.56 mg/mL. The proposed procedure has been successfully applied to the determination of this drug in its tablets. In addition, the spectral data and stability constant for the binuclear copper(II complex of MPT (Cu2MPT2Cl2 have been reported.

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

    Science.gov (United States)

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

    2016-09-15

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

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

    Science.gov (United States)

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

    2011-04-30

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

  4. The time course of photoinactivation of photosystem II in leaves revisited.

    Science.gov (United States)

    Kou, Jiancun; Oguchi, Riichi; Fan, Da-Yong; Chow, Wah Soon

    2012-09-01

    Res 103:7-17, 2010). That is, the single-negative-exponential time course does not provide evidence for photoprotection of functional PS II complexes by photoinactivated, connected neighbours.

  5. Expression of major histocompatibility complex class II and costimulatory molecules in oral carcinomas in vitro.

    Science.gov (United States)

    Villarroel-Dorrego, Mariana; Speight, Paul M; Barrett, A William

    2005-01-01

    Recognition in the 1980 s that keratinocytes can express class II molecules of the Major Histocompatibility Complex (MHC) first raised the possibility that these cells might have an immunological function, and may even act as antigen presenting cells (APC). For effective T lymphocyte activation, APC require, in addition to MHC II, appropriate costimulatory signals. The aim of this study was to determine the expression of MHC class II and the co-stimulatory molecules CD40, CD80 and CD86 in keratinocytes derived from healthy oral mucosa and oral carcinomas. Using flow cytometry, it was confirmed that oral keratinocytes, switch on, expression of MHC class II molecules after stimulation with IFNgamma in vitro. All keratinocyte lines expressed CD40 constitutively; by contrast, CD80 and CD86 were universally absent. Loss of CD80 and CD86 may be one means whereby tumours escape immunological surveillance.

  6. New bioactive silver(I) complexes: Synthesis, characterization, anticancer, antibacterial and anticarbonic anhydrase II activities

    Science.gov (United States)

    Ozdemir, Ummuhan O.; Ozbek, Neslihan; Genc, Zuhal Karagoz; İlbiz, Firdevs; Gündüzalp, Ayla Balaban

    2017-06-01

    Silver(I) complexes of alkyl sulfonic acide hydrazides were newly synthesized as homologous series. Methanesulfonic acide hydrazide (L1), ethanesulfonic acide hydrazide (L2), propanesulfonic acide hydrazide (L3) and butanesulfonic acide hydrazide (L4) were used for complexation with Ag(I) ions. The silver complexes obtained in the mol ratio of 1:2 have the structural formula as Ag(L1)2NO3 (I), Ag(L2)2NO3 (II), Ag(L3)2NO3(III), (Ag(L4)2NO3 (IV). The Ag(I) complexes exhibit distorted linear two-fold coordination in [AgL2]+ cations with uncoordinated nitrates. Ligands are chelated with silver(I) ions through unsubstituted primary nitrogen in hydrazide group. Ag(I) complexes were characterized by using elemental analysis, spectroscopic methods (FT-IR, LC-MS), magnetic susceptibility and conductivity measurements. Silver(I) complexes were optimized using PBEPBE/LanL2DZ/DEF2SV basic set performed by DFT method with the Gaussian 09 program package. The geometrical parameters, frontier molecular orbitals (HOMOs and LUMOs) and molecular electrostatic potential (MEP) mapped surfaces of the optimized geometries were also determined by this quantum set. The anticancer activities of silver(I) complexes on MCF-7 human breast cancer cell line were investigated by comparing IC50 values. The antibacterial activities of complexes were studied against Gram positive bacteria; S. aureus ATCC 6538, B. subtilis ATCC 6633, B. cereus NRRL-B-3711, E. faecalis ATCC 29212 and Gram negative bacteria; E. coli ATCC 11230, P. aeruginosa ATCC 15442, K. pneumonia ATCC 70063 by using disc diffusion method. The inhibition activities of Ag(I) complexes on carbonic anhydrase II enzyme (hCA II) were also investigated by comparing IC50 and Ki values. The biological activity screening shows that Ag(I) complex of butanesulfonicacidehydrazide (IV) has the highest activity against tested breast cancer cell lines MCF-7, Gram positive/Gram negative bacteria and carbonic anhydrase II (hCA II) isoenzyme.

  7. Hydrogenation catalysts based on complexes of palladium(II) and polyvinylpyridines

    Energy Technology Data Exchange (ETDEWEB)

    Zharmagambetova, A.K.; Mukhamedzhanova, S.G.; Bekturov, E.A.; Saltykov, Yu.P.

    1992-05-20

    Recently methods for producing a new type of catalyst, grafted complexes have been developed. Polymers containing functional groups have been used quite successfully as a substrate in such catalysts. The refinement of the preparative method for metallopolymeric complexes (MPC) is of some importance. By varying the conditions of interaction between the polymers and the metal compounds the catalytic properties of MPC can be improved significantly. In this study the authors have looked at the effect of the preparative conditions for complexes of palladium(II) with poly-2-vinylpyridine (Pd-P2VP) on their catalytic activity in the hydrogenation of 2-propen-1-ol. 13 refs., 3 figs., 1 tab.

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

    OpenAIRE

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

    2009-01-01

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

  9. NMR investigation of dynamic processes in complexes of nickel(II) and zinc(II) with iminodiacetate, n-methyliminodiacetate and n-ethyliminodiacetate

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M.R.

    1985-11-01

    Analysis of oxygen-17 bulk water relaxation rates with an aqueous solution of 1:1 Ni(II):ida reveals that two rate-limiting processes are involved with solvent exchange. Analysis of carbon-13 longitudinal relaxation rates of the bis-ligand complexes with zinc(II) are used to determine molecular tumbling rates and methyl rotation rates. The carbon-13 transverse relaxation rates for the carbons in the bis-ligand complex with Ni(II) are adequately fitted to the Solomon-Bloembergen equation. Three carboxylate carbon peaks are seen with the /sup 13/C spectrum of the 1:2 Ni(II):ida complex, which coalesce into a single peak above about 360 K. The mechanism and rate of ligand exchange are determined for the complexes Zn(II)L/sub 2//sup -2/ (L = mida, eida) in aqueous solution by total lineshape analysis of the proton spectrum at 500 MHz.

  10. Enhanced personal protection system for the PS

    CERN Multimedia

    Caroline Duc

    2013-01-01

    During the first long shutdown (LS1) a new safety system will be installed in the primary beam areas of the PS complex in order to bring the standard of personnel radiation protection at the PS into line with that of the LHC.   Pierre Ninin, deputy group leader of GS-ASE and responsible for the installation of the new PS complex safety system, in front of a new access control system. The LHC access control systems are state-of-the-art, whereas those of the injection chain accelerators were running the risk of becoming obsolete. For the past two years a project to upgrade the access and safety systems of the first links in the LHC accelerator chain has been underway to bring them into compliance with nuclear safety standards. These systems provide the personnel with automatic protection by limiting access to hazardous areas and by ensuring that nobody is present in the areas when the accelerator is in operation. By the end of 2013, the project teams will ha...

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

    Science.gov (United States)

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

    2017-01-01

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

  12. Synthesis, spectral characterization, solution equilibria, in vitro antibacterial and cytotoxic activities of Cu(II), Ni(II), Mn(II), Co(II) and Zn(II) complexes with Schiff base derived from 5-bromosalicylaldehyde and 2-aminomethylthiophene

    Science.gov (United States)

    El-Sherif, Ahmed A.; Eldebss, Taha M. A.

    2011-09-01

    Schiff base namely 2-aminomethylthiophenyl-4-bromosalicylaldehyde (ATS)(4-bromo-2-(thiophen-2-yl-imino)methylphenol) and its metal complexes have been synthesized and characterized by elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, ESR and thermal analysis (TGA). The analytical data of the complexes show the formation of 1:2 [M:L] ratio of the formula [ML 2], where M represents Ni(II), Zn(II) and Cu(II) ions, while L represents the deprotonated Schiff base. IR spectra show that ATS is coordinated to the metal ions in a bidentate manner through azomethine-N and phenolic-oxygen groups. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria. A cytotoxicity of the compounds against colon (HCT116) and larynx (HEP2) cancer cells have been studied. Protonation constants of (ATS) ligand and stability constants of its Cu 2+, Co 2+, Mn 2+, Zn 2+ and Ni 2+ complexes were determined by potentiometric titration method in 50% (v/v) DMSO-water solution at ionic strength of 0.1 M NaNO 3.

  13. A cyanide-bridged trinuclear Fe(II)-Ru(II)-Fe(II) complex with three stable states: synthesis, crystal structures, electronic couplings and magnetic properties.

    Science.gov (United States)

    Ma, Xiao; Hu, Sheng-Min; Tan, Chun-Hong; Wen, Yue-Hong; Zhu, Qi-Long; Shen, Chao-Jun; Sheng, Tian-Lu; Wu, Xin-Tao

    2012-10-21

    Treatment of trans-(Ph-tpy)Ru(PPh(3))(CN)(2) (Ph-tpy = 4'-phenyl-2,2':6',2''-terpyridine, PPh(3) = triphenylphosphine) with 2 equiv of Cp(dppe)Fe(NCCH(3))Br (dppe = bis(diphenylphosphino)ethane) in the presence of NH(4)PF(6) produced a trinuclear cyanide-bridged complex, trans-[Cp(dppe)Fe(CN)(Ph-tpy)Ru(PPh(3))(CN)Fe(dppe)Cp][PF(6)](2) (1[PF(6)](2)). Its one-electron oxidation product (1[PF(6)](3)) and two-electron-oxidation product (1[PF(6)](4)) were obtained by oxidation with (Cp)(2)FePF(6) and AgPF(6), respectively. Firstly, the crystal structures of the cyanide-bridged complexes with three stable states were fully characterized. The reversible electrochemistry measurement of 1(2)(+) shows the presence of a long range intervalence interaction between the external iron centres. Both 1(3)(+) and 1(4)(+) were considered to be Class II mixed valence complexes according to the classification of Robin and Day. Magnetic analysis indicated the presence of a moderately strong antiferromagnetic coupling between the two remote Fe(III) ions across the Fe-NC-Ru-CN-Fe array in 1(4)(+). This proves that the Ru(II)-dicyano complex is a bridging ligand that can transmit electro- and magneto-communication.

  14. Mechanisms of energy transfer and conversion in plant Light-Harvesting Complex II

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Tiago Ferreira de

    2009-09-24

    The light-harvesting complex of photosystem II (LHC-II) is the major antenna complex in plant photosynthesis. It accounts for roughly 30% of the total protein in plant chloroplasts, which makes it arguably the most abundant membrane protein on Earth, and binds about half of plant chlorophyll (Chl). The complex assembles as a trimer in the thylakoid membrane and binds a total of 54 pigment molecules, including 24 Chl a, 18 Chl b, 6 lutein (Lut), 3 neoxanthin (Neo) and 3 violaxanthin (Vio). LHC-II has five key roles in plant photosynthesis. It: (1) harvests sunlight and transmits excitation energy to the reaction centres of photosystems II and I, (2) regulates the amount of excitation energy reaching each of the two photosystems, (3) has a structural role in the architecture of the photosynthetic supercomplexes, (4) contributes to the tight appression of thylakoid membranes in chloroplast grana, and (5) protects the photosynthetic apparatus from photo damage by non photochemical quenching (NPQ). A major fraction of NPQ is accounted for its energy-dependent component qE. Despite being critical for plant survival and having been studied for decades, the exact details of how excess absorbed light energy is dissipated under qE conditions remain enigmatic. Today it is accepted that qE is regulated by the magnitude of the pH gradient ({delta}pH) across the thylakoid membrane. It is also well documented that the drop in pH in the thylakoid lumen during high-light conditions activates the enzyme violaxanthin de-epoxidase (VDE), which converts the carotenoid Vio into zeaxanthin (Zea) as part of the xanthophyll cycle. Additionally, studies with Arabidopsis mutants revealed that the photosystem II subunit PsbS is necessary for qE. How these physiological responses switch LHC-II from the active, energy transmitting to the quenched, energy-dissipating state, in which the solar energy is not transmitted to the photosystems but instead dissipated as heat, remains unclear and is the

  15. 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.

  16. Structural, spectral, DFT and biological studies on macrocyclic mononuclear ruthenium (II) complexes

    Science.gov (United States)

    Muthukkumar, M.; Kamal, C.; Venkatesh, G.; Kaya, C.; Kaya, S.; Enoch, Israel V. M. V.; Vennila, P.; Rajavel, R.

    2017-11-01

    Macrocyclic mononuclear ruthenium (II) complexes have been synthesized by condensation method [Ru (L1, L2, L3) Cl2] L1 = (C36 H31 N9), L2= (C42H36N8), L3= (C32H32 N8)]. These ruthenium complexes have been established by elemental analyses and spectroscopic techniques (Fourier transform infrared spectroscopy (FT-IR), 1H- nuclear magnetic resonance (NMR), 13C- NMR and Electrospray ionization mass spectrometry (ESI-MS)). The coordination mode of the ligand has been confirmed and the octahedral geometry around the ruthenium ion has been revealed. Binding affinity and binding mode of ruthenium (II) complexes with Bovine serum Albumin (BSA) have been characterized by Emission spectra analysis. UV-Visible and fluorescence spectroscopic techniques have also been utilized to examine the interaction between ligand and its complexes L1, L2, & L3 with BSA. Chemical parameters and molecular structure of Ru (II) complexes L1H, L2H, & L3H have been determined by DFT coupled with B3LYP/6-311G** functional in both the gaseous and aqueous phases.

  17. Spectroscopic, thermal, catalytic and biological studies of Cu(II) azo dye complexes

    Science.gov (United States)

    El-Sonbati, A. Z.; Diab, M. A.; El-Bindary, A. A.; Shoair, A. F.; Hussein, M. A.; El-Boz, R. A.

    2017-08-01

    New complexes of copper(II) with azo compounds of 5-amino-2-(aryl diazenyl)phenol (HLn) are prepared and investigated by elemental analyses, molar conductance, IR, 1H NMR, UV-Visible, mass, ESR spectra, magnetic susceptibility measurements and thermal analyses. The complexes have a square planar structure and general formula [Cu(Ln)(OAc)]H2O. Study the catalytic activities of Cu(II) complexes toward oxidation of benzyl alcohol derivatives to carbonyl compounds were tested using H2O2 as the oxidant. The intrinsic binding constants (Kb) of the ligands (HLn) and Cu(II) complexes (1-4) with CT-DNA are determined. The formed compounds have been tested for biological activity of antioxidants, antibacterial against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and yeast Candida albicans. Antibiotic (Ampicillin) and antifungal against (Colitrimazole) and cytotoxic compounds HL1, HL2, HL3 and complex (1) showed moderate to good activity against S. aureus, E. coli and Candida albicans, and also to be moderate on antioxidants and toxic substances. Molecular docking is used to predict the binding between the ligands with the receptor of breast cancer (2a91).

  18. Major histocompatibility complex class II deficiency complicated by Mycobacterium avium complex in a boy of mixed ethnicity.

    Science.gov (United States)

    Dimitrova, Dimana; Ong, Peck Y; O'Gorman, Maurice R G; Church, Joseph A

    2014-08-01

    Major histocompatibility complex class II (MHCII) deficiency represents a rare form of severe immunodeficiency associated with increased susceptibility to viral, bacterial, and fungal pathogens and commonly leads to failure to thrive and early death. This autosomal recessive disorder is caused by mutations in MHCII transcription regulator genes, resulting in impaired expression of MHCII, and it is usually seen in consanguineous populations. Our patient presented at age 15 months with a history of developmental delay, multiple respiratory infections and skin abscesses, and recently, at 5 years of age, he was found to have disseminated Mycobacterium avium complex. His mother is Mexican-American, and his father is Persian. Laboratory investigations showed hypogammaglobulinemia, modest T-lymphopenia, borderline mitogen responses, absent tetanus toxoid and candida antigen lymphoproliferative assays, and absent tetanus toxoid and Haemophilus influenzae type b antibody levels. Flow cytometry demonstrated absent HLA-DR antigen on monocytes and B-cells, and a diagnosis of MHCII deficiency was made. Genetic analysis yielded a homozygous pathogenic class II transactivator (CIITA) mutation. The same mutation was found in both parents. Coincidently, an Xq28 microduplication was identified and likely was the cause of the patient's developmental delay. This patient demonstrated some of the typical features of MHCII deficiency with the addition of several unique findings: disseminated M. avium complex, homozygosity in a CIITA mutation despite remarkably diverse parental ethnicity, and coincident Xq28 microdeletion with mild intellectual disability.

  19. Polynuclear complexes incorporating Cu(II) and Mn(II) centers bridged by acetylenedicarboxylate: Structure, thermal stability and magnetism

    Science.gov (United States)

    Shao, Min; Li, Ming-Xing; Dai, Hui; Lu, Wen-Cong; An, Bao-Li

    2007-03-01

    Two acetylenedicarboxylate complexes, [Mn 2(C 4O 4)(phen) 4(H 2O) 2](ClO 4) 2·H 2O ( 1) and [Cu(C 4O 4)(2,2'-bpy)] n ( 2), have been synthesized and characterized by elemental analyses and IR spectra. Mn II ions have distorted octahedral coordination geometry and bridged by C 4O 42- to form a binuclear structure. Thermal analysis shows C 4O 42- released in the range of 180-280 °C. Cu II is five-coordinated by 2,2'-bipyridine and three oxygen atoms from three different C 4O 42- ligands, leading to a square-pyramidal coordination geometry. Each C 4O 42- links three Cu II centers through bifunctional carboxylate to form a polymeric structure of (4, 4) layers with nodes being dimer of Cu 2O 2 and bridges of C 4O 42-. Its variable-temperature magnetism was also investigated.

  20. SYNTHESIS AND CRYSTAL STRUCTURE OF A Ni(II COMPLEX WITH 1,5-NAPHTHALENEDISULFONATE

    Directory of Open Access Journals (Sweden)

    WANG LI-HUA

    2014-11-01

    Full Text Available A new Ni(II complex, [Ni(H2O6]•(L (L=1,5-naphthalenedisulfonate has been obtained by the reaction of Ni(OAc2•4H2O with sodium 1,5-naphthalenedisulfonate in the CH3CH2OH/H2O (V:V=1:1 solution. The complex was characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The results showed that the local geometry around central Ni(II ion can be described as distorted octahedral environment which connected by six coordinated water molecules. The complex molecules formed one dimensional chained structure by hydrogen bonds and π-π stacking.

  1. Bioinorganic Relevance of Some Cobalt(II Complexes with Thiophene-2-glyoxal Derived Schiff Bases

    Directory of Open Access Journals (Sweden)

    Prashant Singh

    2009-01-01

    Full Text Available Complexes of Co(II with two new Schiff bases TEAB [2-hydroxy-4-{[2-oxo-2-(thiophen-2-ylethylidene]amino}benzoic acid] and TEPC [N-[2-oxo-2-(thiophen-2-ylethylidene]pyridine-3-carboxamide] have been synthesized and characterized with the help of elemental analysis, magnetic, mass, 1H-NMR, 13C-NMR, IR and electronic spectral data. IR spectra manifest the coordination of the ligand to the metal ion through the carbonyl oxygen, azomethine nitrogen and thienyl sulphur atoms. With the help of electronic spectral data various ligand field parameters were also calculated. All these studies reveal the distorted octahedral Co(II complexes. Synthesized compounds have also been screened against some micro organisms viz, Escherichia coli, Proteus vulgaris, Aspergillus niger and Aspergillus flavus with the help of ‘filter paper disc’ technique. It has been observed that the antimicrobial activities of metal complexes are higher than that of the free ligand.

  2. Synthesis, characterization and antibacterial activity of new sulfonyl hydrazone derivatives and their nickel(II) complexes

    Science.gov (United States)

    Özmen, Ümmühan Özdemir; Olgun, Gülçin

    2008-08-01

    Prophane sulfonic acid hydrazide (psh: CH 3CH 2CH 2SO 2NHNH 2) derivatives as salicylaldehydeprophanesulfonylhydrazone (salpsh), 5-methylsalicylaldehydeprophanesulfonylhydrazone (5-msalpsh), 2-hydroxyacetophenoneprophanesulfonylhydrazone (afpsh), 5-methyl-2-hydroxyacetophenoneprophanesulfonylhydrazone (5-mafpsh) and their Ni(II) complexes have been synthesized. The structure of these compounds has been investigated by using elemental analysis, FTIR, 1H NMR, LC/MS, UV-vis spectrophotometric method, magnetic susceptibility and conductivity measurements. The complexes were found to have general compositions [NiL2]. Square-planer structures are proposed for the Ni(II) complexes on the basis of magnetic evidence, electronic spectra and TGA data. Bacterial activities of sulfonyl hydrazone compounds were studied against gram-positive bacteria: Staphylococcus aureus, Bacillus subtilis, Bacillus magaterium and gram-negative bacteria: Salmonella enteritidis, Escherichia coli by using minimum inhibitory concentrations (MICs) method.

  3. C{sub 2}-symmetric Copper(II) complexes as chiral Lewis acids

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D.A.; Murry, J.A.; Matt, P. von [Harvard Univ., Cambridge, MA (United States)] [and others

    1995-12-01

    Two new Cu(II)-derived Lewis acid catalysts 1 and 2 have been prepared and their utility as catalysts in the Diels-Alder reaction documented. While complex 1 is effective in catalyzing the cycloaddition of unsaturated aldehyde dienophiles with cyclopentadiene complex 2 is optimal for imide dienophiles. This study provides a rational basis for the design of Lewis acids based on the coordinating capacity of cationic Cu(II) complexes which possess sufficient Lewis acidity to catalyze a range of synthetically useful Diels-Alder reactions. In particular, documentation of the importance of counterion structure in the use of cationic metal centers as Lewis acids has been made for the first time.

  4. Synthesis, spectroscopic and thermal studies of Mg(II), Ca(II), Sr(II) and Ba(II) diclofenac sodium complexes as anti-inflammatory drug and their protective effects on renal functions impairment and oxidative stress

    Science.gov (United States)

    El-Megharbel, Samy M.; Hamza, Reham Z.; Refat, Moamen S.

    2015-01-01

    The main task of our present study is the preparation of newly complexes of Mg(II), Ca(II), Sr(II) and Ba(II) with diclofenac which succeeded to great extent in alleviating the side effects of diclofenac alone and ameliorating the kidney function parameters and antioxidant capacities with respect to diclofenac treated group alone. The Mg(II), Ca(II), Sr(II) and Ba(II) with diclofenac have been synthesized and characterized using infrared, electronic and 1H NMR spectral, thermogravimetric and conductivity measurements. The diclofenac ligand has been found to act as bidentate chelating agent. Diclofenac complexes coordinate through the oxygen's of the carboxyl group. The molar ratio chelation is 1:2 (M2+-dic) with general formula [M(dic)2(H2O)2]ṡnH2O. Antibacterial screening of the alkaline earth metal complexes against Escherichia coli (Gram - ve), Bacillus subtilis (Gram + ve) and anti-fungal (Asperagillus oryzae, Asperagillus niger, Asperagillus flavus) were investigated. The kidney functions in male albino rats were ameliorated upon treatment with metal complexes of dic, which are represented by decreasing the levels of urea and uric acid to be located within normal values. The other looks bright spot in this article is the assessment of antioxidant defense system including SOD, CAT and MDA with the help of Sr2+, Mg2+ and Ca2+-dic complexes. The hormones related to kidney functions and stresses have been greatly ameliorated in groups treated with dic complexes in comparable with dic treated group.

  5. Synthesis, characterization, and biological activity of a new palladium(II) complex with deoxyalliin

    Energy Technology Data Exchange (ETDEWEB)

    Corbi, P.P.; Massabni, A.C. [Inst. de Quimica - UNESP, Dept., Dept. de Quimica Geral e Inoganica, Araraquara (Brazil)]. E-mail: pedrocorbi@yahoo.com; Moreira, A.G. [Inst. de Quimica - UNESP, Dept. de Quimica Geral e Inoganica, Araraquara (Brazil); Faculdade de Medicina de Ribeirao Preto - USP, Dept. de Bioquimica e Imunologia, Ribeirao Preto (Brazil); Medrano, F.J. [Laboratorio Nacional de Luz Sincrotron - LNLS, Campinas (Brazil); Jasiulionis, M.G. [Escola Paulista de Medicina - UNIFESP, Dept. de Micro-Imuno-Parasitologia, Sao Paulo (Brazil); Costa-Neto, C.M. [Faculdade de Medicina de Ribeirao Preto - USP, Dept. de Bioquimica e Imunologia, Ribeirao Preto (Brazil)

    2005-02-15

    Synthesis, characterization, and biological activity of a new water-soluble Pd(II)-deoxyalliin (S-allyl-L-cysteine) complex are described in this article. Elemental and thermal analysis for the complex are consistent with the formula [Pd(C{sub 6}H{sub 10}NO{sub 2}S){sub 2}]. {sup 13}C NMR, {sup 1}H NMR, and IR spectroscopy show coordination of the ligand to Pd(II) through S and N atoms in a square planar geometry. Final residue of the thermal treatment was identified as a mixture of PdO and metallic Pd. Antiproliferative assays using aqueous solutions of the complex against HeLa and TM5 tumor cells showed a pronounced activity of the complex even at low concentrations. After incubation for 24 h, the complex induced cytotoxic effect over HeLa cells when used at concentrations higher than 0.40 mmol/L. At lower concentrations, the complex was nontoxic, indicating its action is probably due to cell cycle arrest, rather than cell death. In agreement with these results, the flow cytometric analysis indicated that after incubation for 24 h at low concentrations of the complex cells are arrested in G0/G1. (author)

  6. Spectral, NLO, Fluorescence, and Biological Activity of Knoevenagel Condensate of β-Diketone Ligands and Their Metal(II Complexes

    Directory of Open Access Journals (Sweden)

    S. Sumathi

    2011-01-01

    Full Text Available Transition metal complexes of various acetylacetone-based ligands of the type ML (where M=  Cu(II, Ni(II, Co(II; L=  3-(aryl-pentane-2,4-dione have been synthesized. The structural features have been derived from their elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, H1NMR, mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are nonelectrolytic in nature. Spectroscopic and other analytical data of the complexes suggest square planar geometry for copper(II, cobalt(II, and nickel(II complexes of 3-(3-phenylallylidenepentane-2,4-dione and octahedral geometry for other metal(II complexes. The redox behaviors of the copper(II complexes have been studied by cyclic voltammetry. The free ligands and their metal complexes have been screened for their in vitro biological activities against bacteria and fungus. The metal(II complexes are found to possess increased activities compared to those of the free ligands. All synthesized compounds may serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG efficiency of the ligands was found to have considerable effect compared to that of urea and KDP.

  7. Synthesis, characterization, DFT calculations and antibacterial activity of palladium(II) cyanide complexes with thioamides

    Science.gov (United States)

    Ahmad, Saeed; Nadeem, Shafqat; Anwar, Aneela; Hameed, Abdul; Tirmizi, Syed Ahmed; Zierkiewicz, Wiktor; Abbas, Azhar; Isab, Anvarhusein A.; Alotaibi, Mshari A.

    2017-08-01

    Palladium(II) cyanide complexes of thioamides (or thiones) having the general formula PdL2(CN)2, where L = Thiourea (Tu), Methylthiourea (Metu), N,N‧-Dimethylthiourea (Dmtu), Tetramethylthiourea (Tmtu), 2-Mercaptopyridine (Mpy) and 2-Mercaptopyrimidine (Mpm) were prepared by reacting K2[PdCl4] with potassium cyanide and thioamides in the molar ratio of 1:2:2. The complexes were characterized by elemental analysis, thermal and spectroscopic methods (IR, 1H and 13C NMR). The structures of three of the complexes were predicted by DFT calculations. The appearance of a band around 2100 cm-1 in IR and resonances around 120-130 ppm in the 13C NMR spectra indicated the coordination of cyanide to palladium(II). More than one resonances were observed for CN- carbon atoms in 13C NMR indicating the existence of equilibrium between different species in solution. DFT calculations revealed that in the case of the palladium(II) complex of Tmtu, the ionic dinuclear [Pd(Tmtu)4][Pd(CN)4] form was more stable than the dimer of mononuclear complex [Pd(Tmtu)2(CN)2] by 0.91 kcal mol-1, while for the complexes of Tu or Mpy ligands, the nonionic [Pd(L)2(CN)2] forms were more stable than the corresponding [Pd(L)4][Pd(CN)4] complexes by 1.26 and 6.49 kcal mol-1 for L = Tu and Mpy, respectively. The complexes were screened for antibacterial effects and some of them showed significant activities against both gram positive as well as gram negative bacteria.

  8. Spiral Dinuclear Complexes of Tetradentate N(4) Diazine Ligands with Mn(II), Fe(II), Fe(III), Co(III), and Ni(II) Salts.

    Science.gov (United States)

    Xu, Zhiqiang; Thompson, Laurence K.; Miller, David O.; Clase, Howard J.; Howard, Judith A. K.; Goeta, Andrés E.

    1998-07-13

    A series of dinuclear complexes of the tetradentate dipyridyl-diazine ligand PAHAP with Mn(II), Fe(II), Fe(III), Co(III), and Ni(II) salts is reported in which three ligands wrap themselves around the six-coordinate metal centers in a rare spiral-like fashion. A similar Fe(II) complex is found for the dipyrazinyl-diazine ligand PZHPZ. The ligands are severely twisted with dihedral angles between the metal chelate ring mean planes on each ligand in the range 50-70 degrees, values close to the expected twist angle for orthogonality between the bridging nitrogen atom p orbitals. Full structures are reported for the dinuclear complexes [Mn(2)(PAHAP)(3)](ClO(4))(4).5H(2)O (1), [Fe(2)(PAHAP)(3)](NO(3))(4).3H(2)O (2), [Fe(2)(PZHPZ)(3)](NO(3))(4).5H(2)O (5), [Co(2)(PAHAP)(3)](NO(3))(6).5H(2)O (6), and [Ni(2)(PAHAP)(3)][Ni(H(2)O)(6)](NO(3))(6).4.5H(2)O (7). Other derivatives [Fe(2)(PAHAP)(3)](ClO(4))(4).4H(2)O (3), [Fe(2)(PAHAP)(3)](ClO(4))(6).4.5H(2)O (4), [Ni(2)(PAHAP)(3)](ClO(4))(4).5H(2)O (8), and [Fe(PHAAP-H)(H(2)O)(2)(NO(3))](NO(3))(2) (9) are also reported. Complex 1 crystallized in the monoclinic system, space group C2/c, with a = 13.4086(2) Å, b = 32.0249(1) Å, c = 14.3132(2) Å, alpha = 90 degrees, beta = 115.635(1) degrees, gamma = 90 degrees, and Z = 4. Complex 2 crystallized in the cubic system, space group Pa&thremacr;, with a = b = c = 21.0024(1) Å, alpha = beta = gamma = 90 degrees, and Z = 8. Complex 5 crystallized in the monoclinic system, space group P2/n, with a = 14.039(3) Å, b = 11.335(6) Å, c = 14.6517(15) Å, beta = 96.852(11) degrees, and Z = 1. Complex 6 crystallized in the trigonal system, space group R&thremacr;c(h), with a = b = 17.386(2) Å, c = 32.15(2) Å, alpha = beta = 90 degrees, gamma = 120 degrees, and Z = 4. Complex 7 crystallized in the trigonal system, space group R&thremacr;c, with a = b = 17.3737(3) Å, c = 33.235(6) Å, alpha = beta = 90 degrees, gamma = 120 degrees, and Z = 27. Weak ferromagnetic coupling was observed for 1

  9. Mn(II) and Cu(II) complexes of a bidentate Schiff's base ligand: Spectral, thermal, molecular modelling and mycological studies

    Science.gov (United States)

    Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

    2014-01-01

    Complexes of manganese(II) and copper(II) of general composition M(L)2X2 have been synthesized [L = 2-acetyl thiophene thiosemicarbazone and X = Cl- and NO3-]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Mn(II) and tetragonal geometry for Cu(II) complexes. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modelling the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p) basis set. The mycological studies of the compounds were examined against the plant pathogenic fungi i.e. Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium odum.

  10. Spectroscopic characterization of chromium(III), manganese(II) and nickel(II) complexes with a nitrogen donor tetradentate, 12-membered azamacrocyclic ligand

    Science.gov (United States)

    Chandra, Sulekh; Pundir, Meenakshi

    2008-01-01

    The complexes of Cr(III), Mn(II) and Ni(II) were synthesized with macrocyclic ligand i.e. 5,11-dimethyl-6,12-diethyl-dione-1,2,4,7,9,10-hexazacyclododeca -1,4,6,10-tetraene. The ligand (L) was prepared by [2 + 2] condensation reaction of 2,3-pentanedione and semicarbazide hydrochloride. These complexes were found to have the general composition [Cr(L)X 2]X and [M(L)X 2] (where M = Mn(II) and Ni(II); X = Cl -, NO 3-, (1/2)SO 42-, NCS - and L = ligand [N 6]). The ligand and its transition metal complexes were characterized by the elemental analysis, molar conductance, magnetic susceptibility, mass, IR, electronic and EPR spectral studies. On the basis of IR, electronic and EPR spectral studies, an octahedral geometry has been assigned for these complexes except sulphato complexes which are of five coordinated geometry.

  11. Mn(II) and Cu(II) complexes of a bidentate Schiff's base ligand: spectral, thermal, molecular modelling and mycological studies.

    Science.gov (United States)

    Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

    2014-01-03

    Complexes of manganese(II) and copper(II) of general composition M(L)2X2 have been synthesized [L=2-acetyl thiophene thiosemicarbazone and X=Cl(-) and NO3(-)]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Mn(II) and tetragonal geometry for Cu(II) complexes. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modelling the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p) basis set. The mycological studies of the compounds were examined against the plant pathogenic fungi i.e. Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium odum. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Synthesis, characterization and electrochemical studies of heterometallic manganese(IV)-zinc(II) and manganese(IV)-copper(II) complexes derived from bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone

    Science.gov (United States)

    Koch, Angira; Phukan, Arnab; Chanu, Oinam B.; Kumar, A.; Lal, R. A.

    2014-02-01

    Five manganese(IV) complexes [Mn(L)(bpy)] (1) and heterobimetallic complexes [MMn(L)Cl2(H2O)4]·1.5H2O (M = ZnII(2), CuII(3)) and [MnM(L)(bpy)Cl2] (M = ZnII(4), CuII(5)] have been synthesized from bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (H4L) in methanol medium. The composition of the complexes have been established based on the data obtained from analytical, thermoanalytical and mass spectral studies. The structures of the complexes have been discussed in the light of molar conductance, magnetic moment, electronic, EPR, IR, FT-IR spectroscopic studies and transmission electron microscopies. The molar conductance values of these complexes in DMSO suggest their non-electrolytic nature. The μeff value for the complexes (1), (2) and (4) fall in the range 3.82-4.12 BM characteristic of the presence of the manganese(IV) in them. The complex (3) has μeff value of 3.70 BM at RT indicating considerable antiferromagnetic interaction between Mn(IV) and Cu(II). The μeff value of 4.72 BM for complex (5) is slightly lower than 4.90 BM for S = 2 ground state. In the complex (1) to (3), the ligand is coordinated to the metal centres as tetradentate ligand while in the complexes (4) and (5) as hexadentate ligand. Manganese(IV) has distorted octahedral stereochemistry in all complexes. Copper(II) has distorted octahedral and square planar stereochemistry in complexes (3) and (5) while zinc has distorted octahedral and tetrahedral stereochemistry, respectively. EPR studies of the complexes are also reported. The electron transfer reactions of the complexes have also been investigated by cyclic voltammetry.

  13. Pocket Semiquinonate Complexes of Cobalt(II), Copper(II), and Zinc(II) Prepared with the Hydrotris(cumenylmethylpyrazolyl)borate Ligand.

    Science.gov (United States)

    Ruf, Michael; Noll, Bruce C.; Groner, Markus D.; Yee, Gordon T.; Pierpont, Cortlandt G.

    1997-10-08

    3,5-Di-tert-butyl-1,2-semiquinonate (3,5-DBSQ) complexes of Co(II), Cu(II), and Zn(II) have been prepared that contain the hydrotris(cumenylmethyl-pyrazolyl)borate (Tp(Cum,Me)) coligand. Tp(Cum,Me)Zn(3,5-DBSQ) and Tp(Cum,Me)Cu(3,5-DBSQ) were prepared by treating the parent hydroxide, Tp(Cum,Me)M(OH), M = Cu and Zn, with 3,5-di-tert-butylcatechol. Tp(Cum,Me)Co(3,5-DBSQ) was prepared by a reaction between (Tp(Cum,Me))(2)Co and 3,5-DBCat. The identity of (Tp(Cum,Me))(2)Co in this reaction was confirmed by a structure determination [(Tp(Cum,Me))(2)Co: orthorhombic, Pbcn, a = 17.7189(4) Å, b = 17.4806(3) Å, c = 25.7123(6) Å, V = 7964.1(3) Å(3), Z = 4, R(F) = 0.054]. Intersecting cumenyl substituents of the pyrazolylborate ligand encapsulate the Co(II) ion. Structural characterization on all three members of the Tp(Cum,Me)M(3,5-DBSQ) series has been carried out. The complexes of Co(II) and Zn(II) are isomorphous and isostructural [Tp(Cum,Me)Co(3,5-DBSQ): triclinic, P&onemacr;, a = 14.4631(2) Å, b = 18.5438(3) Å, c = 21.6142(2) Å, alpha = 79.8430(10) degrees, beta = 90.0900(10) degrees, gamma = 84.9900(10) degrees, V = 5683.45(13) Å(3), Z = 4, R(F) = 0.072; Tp(Cum,Me)Zn(3,5-DBSQ), triclinic, P&onemacr;, a = 14.261(3) Å, b = 18.760(7) Å, c = 21.710(4) Å, alpha = 80.049(12) degrees, beta = 89.853(8) degrees, gamma = 85.542(12) degrees, V = 5703(3) Å(3), Z = 4, R(F) = 0.064]. Tp(Cum,Me)Cu(3,5-DBSQ) [monoclinic, P2(1)/c, a = 19.3081(3) Å, b = 13.0291(2) Å, c = 21.4783(4) Å, beta = 102.8420(10) degrees, V = 5268.1(2) Å(3), Z = 4, R(F) = 0.071] has a distorted square pyramidal structure, the complexes of Zn and Co have structures that are closer to a trigonal bipyramid. Parent catecholate complexes of all three metals are unusually stable in air but undergo slow oxidation in solution to give the semiquinonate products characterized structurally. Copper(II) and SQ spins of Tp(Cum,Me)Cu(3,5-DBSQ) are located in orthogonal orbitals, and the complex has a S = 1 spin

  14. Crystal structures of bis- and hexakis[(6,6′-dihydroxybipyridinecopper(II] nitrate coordination complexes

    Directory of Open Access Journals (Sweden)

    Deidra L. Gerlach

    2015-12-01

    Full Text Available Two multinuclear complexes synthesized from Cu(NO32 and 6,6′-dihydroxybipyridine (dhbp exhibit bridging nitrate and hydroxide ligands. The dinuclear complex (6,6′-dihydroxybipyridine-2κ2N,N′[μ-6-(6-hydroxypyridin-2-ylpyridin-2-olato-1:2κ3N,N′:O2](μ-hydroxido-1:2κ2O:O′(μ-nitrato-1:2κ2O:O′(nitrato-1κOdicopper(II, [Cu2(C10H7N2O2(OH(NO32(C10H8N2O2] or [Cu(6-OH-6′-O-bpy(NO3(μ-OH(μ-NO3Cu(6,6′-dhbp], (I, with a 2:1 ratio of nitrate to hydroxide anions and one partially deprotonated dhbp ligand, forms from a water–ethanol mixture at neutral pH. The hexanuclear complex bis(μ3-bipyridine-2,2′-diolato-κ3O:N,N′:O′tetrakis(6,6′-dihydroxybipyridine-κ2N,N′tetrakis(μ-hydroxido-κ2O:O′bis(methanol-κOtetrakis(μ-nitrato-κ2O:O′hexacopper(II, [Cu6(C10H6N2O22(CH4O2(OH4(NO34(C10H8N2O24] or [Cu(6,6′-dhbp(μ-NO32(μ-OHCu(6,6′-O-bpy(μ-OHCu(6,6′dhbp(CH3OH]2, (II, with a 1:1 NO3–OH ratio and two fully protonated and fully deprotonated dhbp ligands, was obtained by methanol recrystallization of material obtained at pH 3. Complex (II lies across an inversion center. Complexes (I and (II both display intramolecular O—H...O hydrogen bonding. Intermolecular O—H...O hydrogen bonding links symmetry-related molecules forming chains along [100] for complex (I with π-stacking along [010] and [001]. Complex (II forms intermolecular O—H...O hydrogen-bonded chains along [010] with π-stacking along [100] and [001].

  15. Pentagonal Bipyramid FeII Complexes: Robust Ising-Spin Units towards Heteropolynuclear Nanomagnets.

    Science.gov (United States)

    Bar, Arun Kumar; Gogoi, Nayanmoni; Pichon, Céline; Goli, V M L Durga Prasad; Thlijeni, Mehrez; Duhayon, Carine; Suaud, Nicolas; Guihéry, Nathalie; Barra, Anne-Laure; Ramasesha, S; Sutter, Jean-Pascal

    2017-03-28

    Pentagonal bipyramid FeII complexes have been investigated to evaluate their potential as Ising-spin building units for the preparation of heteropolynuclear complexes that are likely to behave as single-molecule magnets (SMMs). The considered monometallic complexes were prepared from the association of a divalent metal ion with pentadentate ligands that have a 2,6-diacetylpyridine bis(hydrazone) core (H2 LN3O2R ). Their magnetic anisotropy was established by magnetometry to reveal their zero-field splitting (ZFS) parameter D, which ranged between -4 and -13 cm-1 and was found to be modulated by the apical ligands (ROH versus Cl). The alteration of the D value by N-bound axial CN ligands, upon association with cyanometallates, was also assessed for heptacoordinated FeII as well as for related NiII and CoII derivatives. In all cases, N-coordinated cyanide ligands led to large magnetic anisotropy (i.e., -8 to -18 cm-1 for Fe and Ni, +33 cm-1 for Co). Ab initio calculations were performed on three FeII complexes, which enabled one to rationalize the role of the ligand on the nature and magnitude of the magnetic anisotropy. Starting from the pre-existing heptacoordinated complexes, a series of pentanuclear compounds were obtained by reactions with paramagnetic [W(CN)8 ]3- . Magnetic studies revealed the occurrence of ferromagnetic interactions between the spin carriers in all the heterometallic systems. Field-induced slow magnetic relaxation was observed for mononuclear FeII complexes (Ueff /kB up to 53 K (37 cm-1 ), τ0 =5×10-9  s), and SMM behavior was evidenced for a heteronuclear [Fe3 W2 ] derivative (Ueff /kB =35 K and τ0 =4.6 10-10  s), which confirmed that the parent complexes were robust Ising-type building units. High-field EPR spectroscopic investigation of the ZFS parameters for a Ni derivative is also reported. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Synthesis, Characterization and Thermal Analysis of New Cu(II Complexes with Hydrazide Ligands

    Directory of Open Access Journals (Sweden)

    Saber Rajaei

    2010-01-01

    Full Text Available A number of new complexes have been synthesized by reaction of novel ligands acetic acid(4-methyl-benzylidenehydrazide (L1 and acetic acid(naphthalen-1-ylmethylenehydrazide (L2 with copper(II nitrate. These new compounds were characterized by elemental analysis, TG, DTA, IR spectroscopy, UV spectral techniques. The changes observed between the FT-IR and UV-Vis spectra of the ligands and of the complexes allowed us to establish the coordination mode of the metal in complexes. The results suggest that the Schiff bases L1 and L2 coordinate as univalent anions with their bidentate N,O donors derived from the carbonyl and azomethine nitrogen. Also the probing of thermal analysis complexes can detect which complex has excellent thermal stability.

  17. Nickel(II) complexes containing thiosemicarbazone and triphenylphosphine: Synthesis, spectroscopy, crystallography and catalytic activity

    Science.gov (United States)

    Priyarega, S.; Kalaivani, P.; Prabhakaran, R.; Hashimoto, T.; Endo, A.; Natarajan, K.

    2011-09-01

    Four new Ni(II) complexes of the general formula [Ni(PPh 3)(L)] (L = dibasic tridentate ligand derived from 4-diethylamino-salicylaldehyde and thiosemicarbazide or 4-N-substituted thiosemicarbazide) have been reported. The new complexes have been synthesized and characterized by analytical and spectroscopic (IR, electronic, 1H NMR and 31P NMR) techniques. Molecular structure of one of the complexes has been determined by X-ray crystallography. The complex, [Ni(PPh 3)(L4)] (H 2L4 = thiosemicarbazone prepared from 4-diethylamino-salicylaldehyde and 4-phenylthiosemicarbazide) crystallized in monoclinic space group with two molecules per unit cell and has the dimensions of a = 13.232(6) Å, b = 10.181(5) Å, c = 13.574(7) Å, α = 90°, β = 98.483(2)° and γ = 90°. Catalytic activity of the complexes has been explored for aryl-aryl coupling reaction.

  18. Antibacterial activity of cobalt(II complexes with some benzimidazole derivatives

    Directory of Open Access Journals (Sweden)

    S. O. PODUNAVAC-KUZMANOVIC

    2008-12-01

    Full Text Available The antibacterial activities of cobalt(II complexes with two series of benzimidazoles were evaluated in vitro against three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus aureus, and Sarcina lutea and one Gram-negative isolate (Pseudomonas aeruginosa. The minimum inhibitory concentration was determined for all the complexes. The majority of the investtigated complexes displayed in vitro inhibitory activity against very persistent bacteria. They were found to be more active against Gram-positive than Gram-negative bacteria. It may be concluded that the antibacterial activity of the compounds is related to the cell wall structure of the tested bacteria. Comparing the inhibitory activities of the tested complexes, it was found that the 1-substituted-2-aminobenzimidazole derivatives were more active than complexes of 1-substituted-2-amino-5,6-dimethylbenzimidazoles. The effect of chemical structure on the antibacterial activity is discussed.

  19. Ruthenium(II) and osmium(II) polypyridyl complexes of an asymmetric pyrazinyl- and pyridinyl-containing 1,2,4-triazole based ligand. Connectivity and physical properties of mononuclear complexes

    NARCIS (Netherlands)

    Browne, Wesley R.; O’Connor, Christine M.; Hughes, Helen P.; Hage, Ronald; Walter, Olaf; Doering, Manfred; Gallagher, John F.; Vos, Johannes G.

    2002-01-01

    The synthesis, purification and characterisation of two coordination isomers of ruthenium(II) and osmium (II) complexes containing the ligand 3-(pyrazin-2'-yl)-5-(pyridin-2"-yl)-1,2,4-triazole (Hppt) are described. The X-ray and molecular structure of the complex [Ru(bipy)(2) (ppt)] PF6.CH3OH (1a)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-15

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

  1. A high quantum yield molecule-protein complex fluorophore for near-infrared II imaging

    Science.gov (United States)

    Antaris, Alexander L.; Chen, Hao; Diao, Shuo; Ma, Zhuoran; Zhang, Zhe; Zhu, Shoujun; Wang, Joy; Lozano, Alexander X.; Fan, Quli; Chew, Leila; Zhu, Mark; Cheng, Kai; Hong, Xuechuan; Dai, Hongjie; Cheng, Zhen

    2017-05-01

    Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. NIR-II fluorophores draw from a broad spectrum of materials spanning semiconducting nanomaterials to organic molecular dyes, yet unfortunately all water-soluble organic molecules with >1,000 nm emission suffer from low quantum yields that have limited temporal resolution and penetration depth. Here, we report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore thus far. The bright molecular complex allowed for the fastest video-rate imaging in the second NIR window with ~50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. In addition, we demonstrate that the NIR-II molecular complexes are superior to clinically approved ICG for lymph node imaging deep within the mouse body.

  2. Formation of binary complexes of Co(II, Ni(II and Cu(II with L-DOPA in dioxan-water mixtures

    Directory of Open Access Journals (Sweden)

    Rama Raju Bendi

    2011-04-01

    Full Text Available Complexation of essential metal ions with (S-2-amino-3-(3,4-dihydroxyphenyl propanoic acid (dopa in (0-60% v/v dioxan-water mixtures has been studied pH-metrically at a temperature of 303 K and an ionic strength of 0.16 M. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. The best-fit chemical models were selected based on statistical parameters like crystallographic R factor and sum of the squares of residuals in mass-balance equations. The models for binary complex systems contain the chemical species ML, ML2, MLH, ML2H and ML2H2 for Co(II, Ni(II and Cu(II in dioxan-water mixtures. The trend in the variation of stability constants with change in the mole fraction of the medium was explained based on electrostatic and non-electrostatic forces. Distribution of the species with pH at different compositions of dioxan-water mixtures was also presented.

  3. In vitro DNA binding studies of the sweetening agent saccharin and its copper(II) and zinc(II) complexes.

    Science.gov (United States)

    Icsel, Ceyda; Yilmaz, Veysel T

    2014-01-05

    The interactions of fish sperm DNA (FS-DNA) with the sodium salt of sweetener saccharin (sacH) and its copper and zinc complexes, namely [M(sac)2(H2O)4]·2H2O (M=Cu(II) or Zn(II)) were studied by using UV-Vis titration, fluorometric competition, thermal denaturation, viscosity and gel electrophoresis measurements. The intrinsic binding constants (Kb) obtained from absorption titrations were estimated to be 2.86 (±0.06)×10(4)M(-1) for Na(sac), 6.67 (±0.12)×10(4)M(-1) for Cu-sac and 4.01 (±0.08)×10(4)M(-1) for Zn-sac. The Cu-sac complex binds to FS-DNA via intercalation with a KA value of 50.12 (±0.22)×10(4)M(-1) as evidenced by competitive binding studies with ethidium bromide. Moreover, competition experiments with Hoechst 33258 are indicative of a groove binding mode of Na(sac) and Zn-sac with binding constants of 3.13 (±0.16)×10(4)M(-1) and 5.25 (±0.22)×10(4)M(-1), respectively. The spectroscopic measurements indicate a moderate DNA binding affinity of Na(sac) and its metal complexes. The suggested binding modes are further confirmed by the thermal denaturation and viscosity measurements. In addition, Cu-sac and Zn-sac show weak ability to damage to pBR322 supercoiled plasmid DNA. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2004-06-21

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-30

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

  6. Synthesis of Ni(II) complexes bearing indole-based thiosemicarbazone ligands for interaction with biomolecules and some biological applications.

    Science.gov (United States)

    Haribabu, Jebiti; Jeyalakshmi, Kumaramangalam; Arun, Yuvaraj; Bhuvanesh, Nattamai S P; Perumal, Paramasivan Thirumalai; Karvembu, Ramasamy

    2017-06-01

    A series of new Ni(II) complexes containing indole-based thiosemicarbazone ligands was synthesized and characterized by elemental analyses, and UV-visible, FT-IR, 1H & 13C NMR and mass spectroscopic techniques. The Ni(II) complexes (1-4) bear the general formula [Ni{C10H9N2NHCSNH(R)}2] where R = hydrogen (1), 4-methyl (2), 4-phenyl (3) and 4-cyclohexyl (4). Molecular structure of ligands (L3 and L4) and complexes (2, 3 and 4) was confirmed by single crystal X-ray crystallography. Four coordinated Ni(II) complexes showed square planar geometry. The interaction of the Ni(II) complexes with calf thymus DNA (CT-DNA) has been evaluated by absorption spectroscopic and ethidium bromide (EB) competitive binding studies, which revealed the intercalative interaction of the complexes with CT-DNA. Gel electrophoresis experiments showed the cleavage of DNA by the complexes without any external agent. Further, the interaction of the complexes with bovine serum albumin (BSA) was investigated using UV-visible, fluorescence and synchronous fluorescence spectroscopic methods, which showed that the complexes could bind strongly with BSA. Molecular docking was employed to understand the binding of the Ni(II) complexes with the molecular target B-DNA, human DNA topoisomerase I and BSA. All the Ni(II) complexes possess high antioxidant activity against 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical and antihaemolytic activity. In addition, in vitro cytotoxicity of the Ni(II) complexes against lung cancer (A549), human breast cancer (MCF7) and mouse embryonic fibroblasts (L929) cell lines was investigated. Complex 4 has high cytotoxicity. The mode of cell death effected by complex 4 has been explored using Hoechst 33258 staining. Nickel(II) complexes of thiosemicarbazone ligands were synthesized and their DNA/protein binding, DNA cleavage and cytotoxicity abilities were studied.

  7. Towards Water Soluble Mitochondria-Targeting Theranostic Osmium(II Triazole-Based Complexes

    Directory of Open Access Journals (Sweden)

    Salem A. E. Omar

    2016-10-01

    Full Text Available The complex [Os(btzpy2][PF6]2 (1, btzpy = 2,6-bis(1-phenyl-1,2,3-triazol-4-ylpyridine has been prepared and characterised. Complex 1 exhibits phosphorescence (λem = 595 nm, τ = 937 ns, φem = 9.3% in degassed acetonitrile in contrast to its known ruthenium(II analogue, which is non-emissive at room temperature. The complex undergoes significant oxygen-dependent quenching of emission with a 43-fold reduction in luminescence intensity between degassed and aerated acetonitrile solutions, indicating its potential to act as a singlet oxygen sensitiser. Complex 1 underwent counterion metathesis to yield [Os(btzpy2]Cl2 (1Cl, which shows near identical optical absorption and emission spectra to those of 1. Direct measurement of the yield of singlet oxygen sensitised by 1Cl was carried out (φ (1O2 = 57% for air equilibrated acetonitrile solutions. On the basis of these photophysical properties, preliminary cellular uptake and luminescence microscopy imaging studies were conducted. Complex 1Cl readily entered the cancer cell lines HeLa and U2OS with mitochondrial staining seen and intense emission allowing for imaging at concentrations as low as 1 μM. Long-term toxicity results indicate low toxicity in HeLa cells with LD50 >100 μM. Osmium(II complexes based on 1 therefore present an excellent platform for the development of novel theranostic agents for anticancer activity.

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

    Science.gov (United States)

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

    2015-09-01

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

  9. Data on the characterization and anticancer action of iron(II polypyridyl complexes

    Directory of Open Access Journals (Sweden)

    Jingjing Chen

    2016-09-01

    The characterization of Fe(II complexes by ESI-MS, 1H NMR, 13C NMR spectroscopy, FT-IR spectra, UV–vis spectra was provided. Also,the data for the stability of Fe(II complexes 1–5 in DMSO/Milli-Q water/ culture medium (without serum or phenol red at 37 °C at different periods of time by UV–vis spectra and 1H NMR was showed. At the same time, the anticancer efficacy, cellular distribution and ROS generation in MCF-7 cells of complexes are reported. In addition, we also show the cellular localization of complex 4, the relative fluorescence intensity of complex 1 and complex 3 pretreated with anti-TfR (2 μg/mL in MCF-7 cells using flow cytometry. The compilation of this data provides an invaluable resource for the wider research community and the interpretation of these data could be found in the research article noted above.

  10. A new Co(II) complex of diniconazole: synthesis, crystal structure and antifungal activity.

    Science.gov (United States)

    Xi, Teng; Li, Jie; Yan, Biao; Yang, Mingyan; Song, Jirong; Ma, Haixia

    2015-10-01

    A new Co(II) complex of diniconazole, namely diaqua[(E)-(RS)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl-κN(4))pent-1-en-3-ol]cobalt(II) dinitrate dihydrate, [Co(C15H17Cl2N3O)3(H2O)2](NO3)2·2H2O, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that the centrosymmetric Co(II) cation is coordinated by four diniconazole ligands and two water molecules, forming a six-coordinated octahedral structure. There are also two free nitrate counter-anions and two additional solvent water molecules in the structure. Intermolecular O-H...O hydrogen bonds link the complex cations into a one-dimensional chain. In addition, the antifungal activity of the complex against Botryosphaeria ribis, Gibberella nicotiancola, Botryosphaeria berengriana and Alternariasolani was studied. The results indicate that the complex shows a higher antifungal activity for Botryosphaeria ribis and Botryosphaeria berengriana than diniconazole, but a lower antifungal activity for Gibberella nicotiancola and Alternariasolani.

  11. Synthesis, characterization, thermal study and biological evaluation of Cu(II), Co(II), Ni(II) and Zn(II) complexes of Schiff base ligand containing thiazole moiety

    Science.gov (United States)

    Nagesh, G. Y.; Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

    2015-01-01

    The novel Schiff base ligand 2-(4-(dimethylamino)benzylidene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 4-dimethylaminobenzaldehyde and its newly synthesized Cu(II), Co(II), Ni(II) and Zn(II) complexes have been characterized by microanalysis, magnetic susceptibility, molar conductance, thermal analysis, FT-IR, 1H NMR, ESI mass, UV-Visible, ESR spectroscopy and powder X-ray diffraction data. The newly synthesized ligand behaves as a bidentate ON donor. The IR results confirmed the bidentate binding of the ligand involving oxygen atom of amide carbonyl and azomethine nitrogen. 1H NMR spectral data of the ligand (L) and its Zn(II) complex agreed well with the proposed structures. In order to evaluate the effect of antimicrobial activity of metal ions upon chelation, the newly synthesized ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were studied using plasmid DNA pBR322 as a target molecule by agarose gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties of all the compounds against Artemia salina. Furthermore, the antioxidant activity of the ligand (L) and its metal complexes were determined in vitro by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH), the ligand exhibited potent in vitro - antioxidant activity than its metal complexes.

  12. Architecture of the RNA polymerase II-TFIIF complex revealed by cross-linking and mass spectrometry

    DEFF Research Database (Denmark)

    Chen, Zhuo Angel; Jawhari, Anass; Fischer, Lutz

    2010-01-01

    Higher-order multi-protein complexes such as RNA polymerase II (Pol II) complexes with transcription initiation factors are often not amenable to X-ray structure determination. Here, we show that protein cross-linking coupled to mass spectrometry (MS) has now sufficiently advanced as a tool to ex...

  13. Mild formation of cyclic carbonates using Zn(II) complexes based on N2S2-chelating ligands

    NARCIS (Netherlands)

    Anselmo, D.; Bocokic, V.; Decortes, A.; Escudero-Adan, E.C.; Benet-Buchholz, J.; Reek, J.N.H.; Kleij, A.W.

    2012-01-01

    We have prepared a series of Zn(II) complexes (1-3) based on a versatile N2S2-chelating ligand abbreviated as btsc [btsc = bis-(thiosemicarbazonato)] derived from simple and accessible building blocks. These complexes comprise a Lewis acidic Zn(II) center useful for substrate activation, and we have

  14. Oxidative double dehalogenation of tetrachlorocatechol by a bio-inspired Cu II complex: formation of chloranilic acid

    NARCIS (Netherlands)

    Bruijnincx, P.C.A.|info:eu-repo/dai/nl/33799529X; Viciano-Chumillas, M.; Lutz, M.|info:eu-repo/dai/nl/304828971; Spek, A.L.|info:eu-repo/dai/nl/156517566; Reedijk, J.; van Koten, G.|info:eu-repo/dai/nl/073839191; Klein Gebbink, R.J.M.|info:eu-repo/dai/nl/166032646

    2008-01-01

    Copper(II) complexes of the potentially tripodal N,N,O ligand 3,3-bis(1-methylimidazol-2-yl)propionate (L1) and its conjugate acid HL1 have been synthesised and structurally and spectroscopically characterised. The reaction of equimolar amounts of ligand and CuII resulted in the complexes

  15. Synthesis, characterization and anti-fungal evaluation of Ni(II and Cu(II complexes with a derivative of 4-aminoantipyrine

    Directory of Open Access Journals (Sweden)

    Monika Tyagi

    2017-01-01

    Full Text Available Transition metal complexes of Ni(II and Cu(II metal ions with the general stoichiometry [M(LX]X and [M(LSO4], where M = Ni(II and Cu(II, L = (1E-N-((5-((E-(2,3-dimethyl-1-phenyl-4-pyrazolineiminomethylthiophen-2-ylmethylene-2,3-dimethyl-1-phenyl-4-pyrazolineamine and X = Cl−, NO3− and SO42−, have been synthesized and characterized. The synthesized ligand and metal complexes were characterized by 1H NMR, IR, mass spectrometry, UV–Vis spectra and EPR. In molecular modelling, the geometries of the Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p basis set. The nickel(II complexes were found to have octahedral geometry, whereas the copper(II complexes were of tetragonal geometry. The covalency factor (β and orbital reduction factor (k suggest the covalent nature of the complexes. To develop broad spectrum new molecules against seed-borne fungi, the minimum inhibitory concentration (MIC of the ligand and its metal complexes was evaluated by the serial dilution method.

  16. Synthesis and Characterization of a Tetramethyl Furanone Functionalized Diiminedioxime, A Potential Ligand for Cu Radiopharmaceuticals, and its Copper(II) and Nickel(II) Complexes.

    Science.gov (United States)

    Kiani, Salma; Staples, Richard J; Treves, S Ted; Packard, Alan B

    2009-03-12

    As part of our on-going effort to develop (64)Cu-based radiopharmaceuticals for PET (positron emission tomography) imaging of multidrug resistance in cancer, we prepared a tetramethylfuranone-functionalized diiminedioxime ligand, TMFPreH (TMFPreH = 4-[3-(4-Hydroxyimino-2,2,5,5-dimethyl-dihydro-furan-3-ylideneamino)-propylimino]-2,2,5,5-tetramethyl-dihydro-furan-3-one oxime) and its Cu(II) and Ni(II) complexes. When the copper(II) complex was prepared from Cu(ClO(4))(2) in ethanol, it was isolated as a Cu(II)-bridged dimer, but when it was prepared from Cu(OAc)(2) and heated in acetone, an unusual example of an acetone adduct of the ligand is formed by reduction of one of the imine double bonds by the solvent. The Ni(II) complex is square pyramidal with the perchlorate counterion at the apex.

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

    Directory of Open Access Journals (Sweden)

    K. A. Kuliev

    2017-01-01

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

  18. Preparation and surface photoelectric properties of Fe(II/III) complexes

    Science.gov (United States)

    Jin, Jing; Xu, Xiao-Ting; Li, Dan; Han, Xiao; Li, Lei; Chi, Yu-Xian; Niu, Shu-Yun; Zhang, Guang-Ning

    2013-05-01

    Four Fe(II/III) supramolecules, {[Fe(Hpdc)2(H2O)2]·2H2O} (1), [Fe(HImbc)2(H2O)2] (2), [Fe(phen)2(CN)2]·CH3CH2OH·2H2O (3), K[Fe(tp)2]·SO4 (4) (H2pdc = 2,5-Pyridinedicarboxylic acid, H2Imbc = 4,5-Imidazoledicarboxylic acid, phen = 1,10-phenanthroline, tp- = poly(pyrazolyl)borate), were synthesized by hydrothermal and room temperature stirring methods. They were characterized by single crystal X-ray diffraction, surface photovoltage spectroscopy (SPS), field-induced surface photovoltage spectroscopy (FISPS), electron paramagnetic resonance (EPR), UV-Vis absorption spectra (UV-Vis), infrared spectra (IR) and element analysis. The structural analyses indicate that complex (1) is a supramolecule with 2D structure connected by hydrogen bonds. Complex (2) is a supramolecule with hydrogen-bonded 3D structure. Complexes (3) and (4) are both 1D supramolecules connected by hydrogen bonds. The electronic state of central metal Fe(II) ions in complexes (1) and (2) is d6 with FeN2O4 coordination mode, lying in weaker distorted octahedral field. The electronic state of Fe(II) ion in complex (3) is d6 with Fe(CN)2N4 mode in the strong distorted octahedral field. The electronic state of Fe(III) ion in complex (4) is d5 with FeN6 mode, lying in the strong octahedral field. The micro-environment of Fe(II/III) ions in the four complexes is further investigated by EPR. The SPS of four complexes all exhibit photovoltage responses in the range of 300-700 nm. This indicates that they all possess certain photoelectric conversion capability. The effects of component, structure, type of ligands of the complexes, valence state and coordination micro-environment of the central metal ions on the SPS were discussed. Furthermore, the SPS and UV-Vis absorption spectra were interrelated.

  19. Structure and spectroscopic investigations of a bi-dentate N‧-[(4-ethylphenyl)methylidene]-4-hydroxybenzohydrazide and its Co(II), Ni(II), Cu(II) and Cd(II) complexes: Insights relevant to biological properties

    Science.gov (United States)

    Gopal Reddy, N. B.; Krishna, P. Murali; Shantha Kumar, S. S.; Patil, Yogesh P.; Nethaji, Munirathinam

    2017-06-01

    The present paper describes the synthesis of novel ligand, N‧-[(4-ethylphenyl)methylidene]-4-hydroxy benzohydrazide (HL) and its Co(II), Ni(II), Cu(II) and Cd(II) complexes. The ligand (HL) crystallizes in orthorhombic lattice in P212121 space group with a = 7.9941 (7) Å, b = 11.6154 (10) Å, c = 15.2278 (13) Å, α = β = γ = 90°. Spectroscopic data gives the strong evidence that ligand is coordinated through azomethine nitrogen and enolic oxygen with metal ion. The DNA binding studies revealed that the complexes bind to CT-DNA via intercalation/electrostatic interaction. All the targeted compounds showed more pronounced DNA cleavage activity in the presence of H2O2 and also inhibit the growth of in vitro antibacterial activity against Gram-positive and Gram-negative bacteria.

  20. PELDOR and RIDME Measurements on a High-Spin Manganese(II) Bisnitroxide Model Complex.

    Science.gov (United States)

    Meyer, Andreas; Schiemann, Olav

    2016-05-26

    A homoleptic bisnitroxide complex of manganese(II) was synthesized as a model system for EPR spectroscopic distance determinations involving high-spin metal ions and more than one distance. The performance of the RIDME experiment is compared with that of the more frequently used PELDOR experiment. It is shown that the PELDOR experiment yields both distances, Mn(II)-nitroxide and nitroxide-nitroxide, and that they can be separated to a certain extent, whereas the RIDME experiment yields only the Mn(II)-nitroxide distance. Both pulse sequences yield artifacts, either due to multispin effects or higher electron-spin transitions. Orientation selection is mostly introduced by the nitroxide signal and can be averaged out by variation of the observer field in the RIDME experiment. Thus, both methods might be used complementarily to obtain a reliable picture of an unknown system.