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Sample records for niii cuii pdii

  1. Elaborated studies for the ligitional behavior of thiouracil derivative towards Ni(II), Pd(II), Pt(IV), Cu(II) and UO2 ² ions.

    PubMed

    Abou-Melha, Khlood Saad

    2012-11-01

    A synthesis of new thiouracil derivative was carried out and deliberately investigated. A new series of complexes was prepared using Ni(II), Pd(II), Pt(IV), Cu(II) and UO(2)(+2) ions. IR spectral data proposed the coordination mod of the ligand towards each metal ion and displays the binegative pentadentate mod as the maximum mod of coordination obtained with Ni(II) and Cu(II) complexes. (1)HNMR spectrum of UO(2)(+2) complex in comparing with the free ligand spectrum supports the binegative appearance of the coordinated ligand through the ionization of CO and CS groups. The electronic spectral data as well as the magnetic moment measurements are coincide with each others to propose the square-planar geometry with Ni(II), Pd(II) and Cu(II) complexes and octahedral geometry with the others. ESR spectrum of Cu(II) complex displays axially symmetric g tensor parameters with g(11)>g(⊥)>2.0023 indicating that the [Formula: see text] orbital as a ground state with the square-planar geometry. The TG analysis for all isolated complexes were carried out to assert about the presence of water molecules physically or chemically attached with the central atom. The biological study was carried out against different microorganisms as gram negative, gram positive and fungi. The comparable data display the relative priority of Ni(II) complex in comparing with others against all organisms but, the other complexes display activity by the same with the free ligand.

  2. Synthesis, antimicrobial activity, structural and spectral characterization and DFT calculations of Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5-pyrimidinecarbonitrile.

    PubMed

    Mohamed, Tarek A; Shaaban, Ibrahim A; Farag, Rabei S; Zoghaib, Wajdi M; Afifi, Mahmoud S

    2015-01-25

    Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5-pyrimidinecarbonitrile (APC) have been synthesized and characterized using elemental analysis, magnetic susceptibility, mass spectrometry, infrared (4000-200 cm(-1)), UV-Visible (200-1100 nm), (1)H NMR and ESR spectroscopy as well as TGA analysis. The molar conductance measurements in DMSO imply non-electrolytic complexes, formulated as [M(APC)2Cl2] where M=Co(II), Ni(II), Cu(II) and Pd(II). The infrared spectra of Co(II), Ni(II) and Cu(II) complexes indicate a bidentate type of bonding for APC through the exocyclic amino and adjacent pyrimidine nitrogen as donors whereas APC coordinated to Pd(II) ion as a monodentated ligand via a pyrimidine nitrogen donor. The magnetic measurements and the electronic absorption spectra support distorted octahedral geometries for Co(II), Ni(II) and Cu(II) complexes however a square planar complex was favored for the Pd(II) complex (C2h skeleton symmetry). In addition, we carried out B3LYP and ω-B97XD geometry optimization at 6-31G(d) basis set except for Pd(II) where we implemented LanL2DZ/6-31G(d) combined basis set. The computational results favor all trans geometrical isomers where amino N, pyrimidine N and Cl are trans to each other (structure 1). Finally, APC and its divalent metal ion complexes were screened for their antibacterial activity, and the synthesized complexes were found to be more potent antimicrobial agents than APC against one or more microbial species.

  3. Synthesis, antimicrobial activity, structural and spectral characterization and DFT calculations of Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5-pyrimidinecarbonitrile

    NASA Astrophysics Data System (ADS)

    Mohamed, Tarek A.; Shaaban, Ibrahim A.; Farag, Rabei S.; Zoghaib, Wajdi M.; Afifi, Mahmoud S.

    2015-01-01

    Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5-pyrimidinecarbonitrile (APC) have been synthesized and characterized using elemental analysis, magnetic susceptibility, mass spectrometry, infrared (4000-200 cm-1), UV-Visible (200-1100 nm), 1H NMR and ESR spectroscopy as well as TGA analysis. The molar conductance measurements in DMSO imply non-electrolytic complexes, formulated as [M(APC)2Cl2] where M = Co(II), Ni(II), Cu(II) and Pd(II). The infrared spectra of Co(II), Ni(II) and Cu(II) complexes indicate a bidentate type of bonding for APC through the exocyclic amino and adjacent pyrimidine nitrogen as donors whereas APC coordinated to Pd(II) ion as a monodentated ligand via a pyrimidine nitrogen donor. The magnetic measurements and the electronic absorption spectra support distorted octahedral geometries for Co(II), Ni(II) and Cu(II) complexes however a square planar complex was favored for the Pd(II) complex (C2h skeleton symmetry). In addition, we carried out B3LYP and ω-B97XD geometry optimization at 6-31G(d) basis set except for Pd(II) where we implemented LanL2DZ/6-31G(d) combined basis set. The computational results favor all trans geometrical isomers where amino N, pyrimidine N and Cl are trans to each other (structure 1). Finally, APC and its divalent metal ion complexes were screened for their antibacterial activity, and the synthesized complexes were found to be more potent antimicrobial agents than APC against one or more microbial species.

  4. Spectroscopic evaluation for VO(II), Ni(II), Pd(II) and Cu(II) complexes derived from thiosemicarbazide: A special emphasis on EPR study and DNA cleavage

    NASA Astrophysics Data System (ADS)

    El-Metwally, Nashwa M.; Al-Hazmi, Gamil A. A.

    2013-04-01

    Some thiosemicarbazide complexes were prepared and deliberately investigated by all allowed tools. The ligand coordinates as a mono negative bidentate towards VO(II) and Ni(II) as well as a neutral bidentate towards Pd(II) and Cu(II) ions. Electronic spectral data beside the magnetic measurements facilitate the structural geometry proposal. EPR spectra of Cu(II) and VO(II) complexes were recorded in their solid state. Spin Hamiltonian parameters and molecular orbital coefficient for Cu(II) and VO(II) complexes were calculated and supporting the octahedral geometry of Cu(II) complex and a square pyramidal for VO(II) one. The biological activity investigation was studied by the use of all prepared compounds. The VO(II) and Cu(II) complexes display the susceptible biotoxicity against a gram-positive bacterium. Also, Cu(II) complex displays the same toxicity against gram-negative bacteria used. The effect of all compounds on DNA were photographed. A successive degradation for the DNA target was observed with Pd(II) and Ni(II) complexes beside their original ligand.

  5. 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

    NASA Astrophysics Data System (ADS)

    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.

  6. A new approach for simultaneous determination of Co(II), Ni(II), Cu(II) and Pd(II) using 2-thiophenaldehyde-3-thiosemicarbazone as reagent by solid phase microextraction-high performance liquid chromatography.

    PubMed

    Kaur, Varinder; Aulakh, Jatinder Singh; Malik, Ashok Kumar

    2007-11-05

    A new method is proposed herein for the sorption, separation and simultaneous determination of Co(II), Ni(II), Cu(II) and Pd(II) using 2-thiophenaldehyde-3-thiosemicarbazone (TPTS) as a reagent by solid phase microextraction-high performance liquid chromatography-UV detection. The method is based upon the sorption of metal complexes on polydimethylsiloxane (PDMS) fiber from aqueous solution followed by desorption in the desorption chamber of solid phase microextraction-high performance liquid chromatography (SPME-HPLC) interface. Reversed phase high performance liquid chromatography using acetonitrile:water (65:35) as an eluent on a C18 column has been used to achieve the separation. The effects of agitation, addition of salts, extraction time and desorption time are examined to obtain optimized conditions. The detection limits for Co(II), Ni(II), Cu(II) and Pd(II) are 9, 6, 1 and 7 ng L(-1) based on 3sigma of blank response. The precision is calculated to be less than 3.5% (R.S.D.) for all species. A 10 time enhancement in the signal is observed for SPME when compared with direct analysis. The method is successfully applied to several synthetic mixtures without interference from other common metal ions such as Mo(VI), V(V), Ag(I), Sn(IV), Cd(II), Zn(II), Pb(II), Cr(III) and Cr(VI). The proposed method is tested for the determination of Co(II), Ni(II), Cu(II) and Pd(II) in alloys and water samples spiked with these metal ions.

  7. Coordination of Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with 2,5-hexanedione bis(thiosemicarbazone), HBTS: Crystal structure of cis-[Pd(HBTS)]Cl2 and 1-(2,5-dimethyl-1H-pyrrol-yl)-thiourea

    NASA Astrophysics Data System (ADS)

    Jeragh, Bakir; El-Asmy, Ahmed A.

    2014-09-01

    Metal complexes of Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pd2+ or Pt2+ with 2,5-hexanedione bis(thiosemicarbazone), HBTS; have been prepared and spectroscopically investigated. The empirical formulae of the complexes were suggested based on the elemental analysis. Single crystal of Pd(II) has been solved to be cis-form of square-planar geometry by the X-ray crystallography. 1H and 13C NMR spectra have been recorded for HBTS, Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) complexes, in DMSO-d6, showing the mode of chelation. The ligand acts as a neutral or a binegative tetradentate (N2S2) or neutral bidentate on the basis of FT-IR. The magnetic moments and electronic spectra provide information about the geometry of the complexes which supported by calculating the ligand field parameters for the Co(II) and Fe(III) complexes. The Ni(II) complex has subnormal magnetic moment (0.71 BM) indicative of a mixed stereochemistry of square-planar and tetrahedral structure. [Cu(HBTS-2H)] measured 0.93 BM indicating high interaction between the copper centers. The ligand may be ordered at the top of the spectrochemical series which giving high ligand field splitting energy (10Dq = 17,900 cm-1 for Co2+ complex). The mass spectra of some complexes proved their stable chemical formulae while the TGA depicts the degradation steps and the final residue. In evaporating the mother liquor during the preparation of HBTS, new compound is obtained naming 1-(2,5-dimethyl-1H-pyrrol-yl)thiourea and its crystal was solved.

  8. A study on the inhibition kinetics of bioaccumulation of Cu(II) and Ni(II) ions using Rhizopus delemar.

    PubMed

    Açikel, Unsal; Alp, Tuğba

    2009-09-15

    The microbial growth and simultaneous bioaccumulation of Cu(II) and Ni(II) ions during the growth of Rhizopus delemar in molasses medium was investigated in a batch system. The level of Cu(II) and Ni(II) bioaccumulation and microbial growth was dependent on pH, molasses sucrose concentration and initial Cu(II) and Ni(II) ion concentrations. An increase in initial total metal ion concentration inhibited both the growth rate of fungus and the bioaccumulation capacity. Lineweaver-Burk plot of Monod equation was used to study the inhibition kinetics of bioaccumulation of Cu(II) and Ni(II) and the intrinsic and apparent model parameters were evaluated in metals-free and metals-contaminated fermentation media. The maximum specific growth rate (micro(m)) and the Monod constant (K(s)) of microorganism in metals-free media were found as 0.405 L/h and 3.977 g/L, respectively. As micro(m) remained constant in the presence of increasing concentrations of Cu(II) and Ni(II) ions, the combined inhibition of Cu(II) and Ni(II) ions on the growth rate of R. delemar was found to be a competitive inhibition. The inhibition constants for Cu(II) and Ni(II) ions were determined as 56.71 mg Cu(II)/L and 47.44 mg Ni(II)/L. As the bioaccumulation of Cu(II) and Ni(II) ions was reduced by the presence of increasing concentrations of the other metal ion, compared with the single-metal systems, the individual action of Cu(II) and Ni(II) ions on the bioaccumulation of R. delemar was generally found to be antagonistic. On the other hand, the total combined effects of Cu(II) and Ni(II) ions on the bioaccumulation of R. delemar are thought to be synergistic since the total bioaccumulated metal ion quantities per unit mass of biomass were higher than those obtained in the growth media containing Cu(II) and Ni(II) ions alone at the same concentrations.

  9. Removal of Cu(II) and Ni(II) from aqueous solution by lignite-based humic acids

    SciTech Connect

    Arslan, G.; Cetin, S.; Pehlivan, E.

    2007-07-01

    The removal of Cu(II) and Ni(II) metal ions from an aqueous solution were investigated by using humic acids (HAs) in a batch arrangement. HAs were prepared by using alkaline extraction, following sedimentation and acidic precipitation from three Turkish lignites: Ilgin, Beysehir, and Ermenek. The interactions of Cu(II) and Ni(II) with solid HAs and influence of three parameters (initial metal concentration, solution pH and temperature) on the removal of metals were studied. Adsorption equilibrium was achieved in about 120 min for Cu(II) and Ni(II) ions. The sorption of Cu(II) and Ni(II) on the surface of HAs depended strongly on the pH, and increased with increasing pH and the initial concentration of metal. The sorption of Cu(II) was higher than that of Ni(II) for HAs. The equilibrium relationship between adsorbent and adsorbate is described by adsorption isotherms at a fixed temperature 35 {sup o}C, at pH about 4.0. The Langmuir adsorption isotherm was used to describe observed sorption phenomena. Adsorption isotherms and kinetics data of Cu(II) and Ni(II) ions removed by HAs are presented and discussed.

  10. Cu(II) and Pd(II) complexes of water soluble O-carboxymethyl chitosan Schiff bases: Synthesis, characterization.

    PubMed

    Baran, Talat; Menteş, Ayfer

    2015-08-01

    This study reports the synthesis of two new water soluble O-carboxymethyl chitosan Schiff bases (OCMCS-5 and OCMCS-6a) and their Cu(II) and Pd(II) complexes. Characterizations of these complexes were carried out with FTIR, elemental analysis, (13)C CPMAS, UV-vis, magnetic moment and molar conductivity techniques. The degrees of substitution (DS) for OCMCS-5a and OCMCS-6a were determined to be 0.48 and 0.44 in elemental analysis. The solubility test revealed that OCMCS-5a and OCMCS-6a dissolved thoroughly in water. The surface morphologies of chitosan (CS), OCMCS-5a, OCMCS-6a and their complexes were studied with SEM-EDAX. Thermal stability of the synthesized compounds was evaluated by TG/DTG and their crystallinity values were investigated with powder X-ray diffraction. Cu(II) and Pd(II) contents of the complexes were estimated with ICP-OES. The characterization studies demonstrated that the thermal stability and crystallinity values of the OCMCS-5a and OCMCS-6a were lower than those of CS.

  11. Adsorption of Cu(II), Ni(II) and Zn(II) on modified jute fibres.

    PubMed

    Shukla, S R; Pai, Roshan S

    2005-09-01

    The potential of a lignocellulosic fibre, jute, was assessed for adsorption of heavy metal ions like Cu(II), Ni(II) and Zn(II) from their aqueous solutions. The fibre was also used as adsorbent after chemically modifying it by two different techniques viz, loading of a dye with specific structure, C.I. Reactive Orange 13, and oxidising with hydrogen peroxide. Both the modified jute fibres gave higher metal ion adsorption. Thus, the dye loaded jute fibres showed metal ion uptake values of 8.4, 5.26 and 5.95 mg/g for Cu(II), Ni(II) and Zn(II), respectively, while the corresponding values for oxidised jute fibres were 7.73, 5.57 and 8.02 mg/g, as against 4.23, 3.37 and 3.55 mg/g for unmodified jute fibres. Adsorption isotherm models indicated best fit for Langmuir model for the modified jute fibres. The adsorption values decreased with lowering of pH. The desorption efficiency, regenerative and reuse capacity of these adsorbents were also assessed for three successive adsorption-desorption cycles. The adsorptive capacity was retained only when the caustic soda regeneration is carried out as an intermediate step after desorption. Possible mechanism has been given.

  12. Unexpected Ni(II) and Cu(II) polynuclear assemblies--a balance between ligand and metal ion coordination preferences.

    PubMed

    Shuvaev, Kontantin V; Tandon, Santokh S; Dawe, Louise N; Thompson, Laurence K

    2010-07-14

    Polytopic ligand design involves matching the coordination pocket composition with the metal ion coordination 'algorithm', but despite targeting [4 x 4] grids as the final outcome, metal ion preferences and ligand control can lead to widely varying complexes in the self-assembly process with Ni(II) and Cu(II).

  13. Spectroscopic and mycological studies of Co(II), Ni(II) and Cu(II) complexes with 4-aminoantipyrine derivative

    NASA Astrophysics Data System (ADS)

    Sharma, Amit Kumar; Chandra, Sulekh

    2011-10-01

    Complexes of the type [M(L)X 2], where M = Co(II), Ni(II) and Cu(II), have been synthesized with novel NO-donor Schiff's base ligand, 1,4-diformylpiperazine bis(4-imino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one) which is obtained by the acid catalyzed condensation of 1,4-diformylpiperazine with 4-aminoantipyrine. The elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV, NMR, mass and EPR studies of the compounds led to the conclusion that the ligand acts as tetradentate chelate. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Ni(II) and tetragonal geometry for Co(II) and Cu(II) complexes. The mycological studies of the compounds were examined against the several opportunistic pathogens, i.e., Alternaria brassicae, Aspergillus niger and Fusarium oxysporum. The Cu(II) complexes were found to have most fungicidal behavior.

  14. Adsorptive removal of Cu(II) and Ni(II) from single-metal, binary-metal, and industrial wastewater systems by surfactant-modified alumina.

    PubMed

    Khobragade, Moni U; Pal, Anjali

    2015-01-01

    Batch adsorption was carried out to investigate the possibility of utilizing surfactant-modified alumina (SMA) as an adsorbent for the removal of Cu(II) and Ni(II) from single-metal and binary-metal solutions. Scanning electron microscopic (SEM) images of SMA before and after metal removal from single-metal matrix, showed no significant changes, whereas energy dispersive X-ray (EDX) studies confirmed the incorporation of Cu(II) (∼ 0.74 atomic%) and Ni(II) (∼ 0.64 atomic%) on the adsorbent surface. The removal of Cu(II) and Ni(II), using SMA depends on contact time, adsorbent dose and medium pH. The sorption kinetics followed pseudo-second-order model for Cu(II). However, for Ni(II), either pseudo-first-order or pseudo-second-order model is applicable. The batch experimental data were fitted to Langmuir and Freundlich isotherm, and based on the correlation coefficient value (R(2)), the adsorption could be described more precisely by the Freundlich isotherm. The maximum adsorption capacity from Langmuir isotherm of Cu(II) was 9.34 mg g(-1) and for Ni(II) 6.87 mg g(-1). In a synthetic binary mixture of Cu(II) and Ni(II), having a concentration of 10 mg L(-1) each, removal of Cu(II) was better. The treatment method was further applied to real wastewater from an electroplating industry. The batch experiment results showed that SMA was effective in the simultaneous removal of Cu(II) and Ni(II) to a significant extent, with additional improvement of water quality of the industrial effluent considered.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Adsorption of Cd(II), Cu(II) and Ni(II) ions by cross-linking chitosan/rectorite nano-hybrid composite microspheres.

    PubMed

    Zeng, Lixuan; Chen, Yufei; Zhang, Qiuyun; Guo, Xingmei; Peng, Yanni; Xiao, Huijuan; Chen, Xiaocheng; Luo, Jiwen

    2015-10-05

    Chitosan/rectorie (CTS/REC) nano-hybrid composite microsphere was prepared by changing the proportion of CTS/REC with 2:1, 3:1 and 4:1. Compared with the pure cross-linking chitosan microsphere, the nano-hybrid composite microsphere was proved to have better sorption capacity of Cd(II), Cu(II) and Ni(II), especially 2:1(CTS/REC-1). The adsorption behavior of the microsphere of Cd(II), Cu(II) and Ni(II) was investigated in single and binary metal systems. In single system, the equilibrium studies showed that the adsorption of Cd(II), Cu(II) and Ni(II) followed the Langmuir model and the pseudo-second-order kinetic model. The negative values of (ΔG) suggested that the adsorption process was spontaneous. In binary system, the combined action of the metals was found to be antagonistic and the metal sorption followed the order of Cu(II)>Cd(II)>Ni(II). The regeneration studies indicated that EDTA desorbed Cd(II), Cu(II) and Ni(II) from cross-linking microspheres better than HCl. The FT-IR and XPS spectra showed that coordination bonds were formed between Cd(II), Cu(II) and Ni(II) and the nitrogen atoms of cross-linking CTS/REC nano-hybrid composite microspheres.

  17. Isolation and spectroscopic characterization of Zn(II), Cu(II), and Pd(II) complexes of 1,3,4-thiadiazole-derived ligand

    NASA Astrophysics Data System (ADS)

    Karcz, Dariusz; Matwijczuk, Arkadiusz; Boroń, Bożena; Creaven, Bernadette; Fiedor, Leszek; Niewiadomy, Andrzej; Gagoś, Mariusz

    2017-01-01

    A series of complexes incorporating Zn(II), Cu(II), and Pd(II) ions, and 4-(5-heptyl-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (L1) as model ligand, was synthesized in order to examine the nature of potential interactions between biologically active ligands, 1,3,4-thiadiazoles and metal ions with proven biological relevance. The structures of the compounds isolated were characterized using a number of spectroscopic methods including IR, Uv-vis, AAS, steady state and time-resolved fluorescence (TRF). The results obtained suggest that the L1-Zn(II) and L1-Pd(II) complexes consist of one molecule of L1 and one acetate ion acting as ligands, while the L1-Cu(II) complex adapts a 2:1 (L1: metal) stoichiometry. The coordination of L1 to metal ions occurs most likely via one of the deprotonated hydroxyl groups of the resorcinyl moiety and one of the N atoms of the thiadiazole heterocycle.

  18. Synthesis and characterization of Co(II), Ni(II) and Cu(II) complexes involving hydroxy antipyrine azodyes

    NASA Astrophysics Data System (ADS)

    Gaber, M.; Hassanein, A. M.; Lotfalla, A. A.

    2008-03-01

    The complexes formed between some hydroxy antipyrine azodyes and Co(II), Ni(II) and Cu(II) ions were studied spectrophotometrically in solution. The stoichiometry and stability constants of the metal chelates were determined. The spectrophotometric determination of the titled metal ions and titration using EDTA were reported. The chelating behaviour of the azodyes was confirmed by preparing the solid chelates in which their structures are elucidated using molar conductance, elemental, thermogravimetric (TGA) analyses, IR, ESR and electronic spectra as well as the magnetic measurements. Kinetic parameters are computed from the thermal decomposition data. The electrical properties for the metal complexes are measured from which the activation energies are calculated.

  19. Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers.

    PubMed

    Monier, M; Ayad, D M; Sarhan, A A

    2010-04-15

    The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  20. Competitive sorption of Pb(II), Cu(II) and Ni(II) on carbonaceous nanofibers: A spectroscopic and modeling approach.

    PubMed

    Ding, Congcong; Cheng, Wencai; Wang, Xiangxue; Wu, Zhen-Yu; Sun, Yubing; Chen, Changlun; Wang, Xiangke; Yu, Shu-Hong

    2016-08-05

    The competitive sorption of Pb(II), Cu(II) and Ni(II) on the uniform carbonaceous nanofibers (CNFs) was investigated in binary/ternary-metal systems. The pH-dependent sorption of Pb(II), Cu(II) and Ni(II) on CNFs was independent of ionic strength, indicating that inner-sphere surface complexation dominated sorption Pb(II), Cu(II) and Ni(II) on CNFs. The maximum sorption capacities of Pb(II), Cu(II) and Ni(II) on CNFs in single-metal systems at a pH 5.5±0.2 and 25±1°C were 3.84 (795.65mg/g), 3.21 (204.00mg/g) and 2.67 (156.70mg/g)mmol/g, respectively. In equimolar binary/ternary-metal systems, Pb(II) exhibited greater inhibition of the sorption of Cu(II) and Ni(II), demonstrating the stronger affinity of CNFs for Pb(II). The competitive sorption of heavy metals in ternary-metal systems was predicted quite well by surface complexation modeling derived from single-metal data. According to FTIR, XPS and EXAFS analyses, Pb(II), Cu(II) and Ni(II) were specifically adsorbed on CNFs via covalent bonding. These observations should provide an essential start in simultaneous removal of multiple heavy metals from aquatic environments by CNFs, and open the doorways for the application of CNFs.

  1. Removal of Cu(II) and Ni(II) ions from an aqueous solution using α-Fe₂O₃nanoparticle-coated volcanic rocks.

    PubMed

    Zhu, Xianfang; Song, Tiehong; Lv, Zhuo; Ji, Guodong

    2015-01-01

    An adsorbent, volcanic rocks coated with α-Fe₂O₃nanoparticles, was prepared and utilized for the removal of Cu(II) and Ni(II) ions from an aqueous solution. Characterization of the coated volcanic rocks indicated that the α-Fe₂O₃nanoparticles were successfully and homogeneously distributed on the volcanic rocks, including penetration into rock pores. Batch experiments were conducted to investigate adsorption performance. The adsorption behavior of both ions was found to best fit a pseudo second-order model and Langmuir isotherm. The maximum adsorption capacities of Cu(II) and Ni(II) ions were 58.14 mg g⁻¹ and 56.50 mg g⁻¹ at 293 K, respectively, and increased with rising temperature. The loaded α-Fe₂O₃nanoparticles onto volcanic rock significantly increased removal of Cu(II) and Ni(II) ions. The adsorption process was combined control of film diffusion and intra-particle diffusion. Adsorption thermodynamics indicated the adsorption process was spontaneous and occurred mainly through chemisorption. The results confirmed that the volcanic rocks coated with α-Fe₂O₃nanoparticles acted as a high-efficiency and low-cost absorbent, and effectively removed Cu(II) and Ni(II) from wastewater.

  2. Spectral studies on Co(II), Ni(II) and Cu(II) complexes with thiosemicarbazone (L1) and semicarbazone (L2) derived from 2-acetyl furan.

    PubMed

    Chandra, Sulekh; Kumar, Anil

    2007-04-01

    Co(II), Ni(II) and Cu(II) complexes are synthesized with thiosemicarbazone (L1) and semicarbazone (L2) derived from 2-acetyl furan. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMSO correspond to non-electrolytic nature except Ni(L)2(NO3)2, which is 1:2 electrolyte. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry may be assigned for Co(II) and Ni(II) complexes except nitrato complexes of Ni(II) which is of tetrahedral geometry, whereas tetragonal geometry for Cu(II) complexes.

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

    PubMed

    Chandra, Sulekh; Kumar, Anil

    2007-12-31

    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.

  4. Heterodinuclear Ni(ii) and Cu(ii) Schiff base complexes and their activity in oxygen reduction.

    PubMed

    Realista, Sara; Ramgi, Priscila; Cardoso, Bernardo de P; Melato, Ana I; Viana, Ana S; Calhorda, Maria José; Martinho, Paulo N

    2016-10-07

    New Cu(ii)/Ni(ii) heterodinuclear complexes with salphen-type ligands were synthesised via a stepwise template method. DFT studies were performed to understand their electronic properties, showing localisation of the HOMO on the Ni(ii) fragment, while in the oxidised species the spin density was high at some carbon phenolate atoms. These new complexes were potentiodynamically electropolymerised on glassy carbon and platinum. Atomic force microscopy was used to evaluate the influence of the metal centres on the morphology of the polymers, revealing how the presence of Cu(ii) increased the surface roughness. The oxygen reduction reaction was observed on both glassy carbon and platinum modified electrodes in neutral medium.

  5. Antibacterial Co(II), Cu(II), Ni(II) and Zn(II) Complexes of Thiadiazoles Schiff Bases

    PubMed Central

    Jaffery, Maimoon F.; Supuran, Claudiu T.

    2001-01-01

    Schiff bases were obtained by condensation of 2-amino-l,3,4-thiadiazole with 5-substituted-salicylaldehydes which were further used to obtain complexes of the type [M(L)2]Cl2, where M=Co(II), Cu(II), Ni(II) or Zn(II). The new compounds described here have been characterized by physical, spectral and analytical data, and have been screened for antibacterial activity against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of these Schiff bases increased upon chelation/complexation, against the tested bacterial species, opening new aproaches in the fight against antibiotic resistant strains. PMID:18475981

  6. Competitive sorption and selective sequence of Cu(II) and Ni(II) on montmorillonite: Batch, modeling, EPR and XAS studies

    NASA Astrophysics Data System (ADS)

    Yang, Shitong; Ren, Xuemei; Zhao, Guixia; Shi, Weiqun; Montavon, Gilles; Grambow, Bernd; Wang, Xiangke

    2015-10-01

    Heavy metal ions that leach from various industrial and agricultural processes are simultaneously present in the contaminated soil and water systems. The competitive sorption of these toxic metal ions on the natural soil components and sediments significantly influences their migration, bioavailability and ecotoxicity in the geochemical environment. In this study, the competitive sorption and selectivity order of Cu(II) and Ni(II) on montmorillonite are investigated by combining the batch experiments, X-ray diffraction (XRD), electron paramagnetic resonance (EPR), surface complexation modeling and X-ray Absorption Spectroscopy (XAS). The batch experimental data show that the coexisting Ni(II) exhibits a negligible influence on the sorption behavior of Cu(II), whereas the coexisting Cu(II) reduces the Ni(II) sorption percentage and changes the shape of the Ni(II) sorption isotherm. The sorption species of Cu(II) and Ni(II) on montmorillonite over the acidic and near-neutral pH range are well simulated by the surface complexation modeling. However, this model cannot identify the occurrence of surface nucleation and the co-precipitation processes at a highly alkaline pH. Based on the results of the EPR and XAS analyses, the microstructures of Cu(II) on montmorillonite are identified as the hydrated free Cu(II) ions at pH 5.0, inner-sphere surface complexes at pH 6.0 and the surface dimers/Cu(OH)2(s) precipitate at pH 8.0 in the single-solute and the binary-solute systems. For the Ni(II) sorption in the single-solute system, the formed microstructure varies from the hydrated free Ni(II) ions at the pH values of 5.0 and 6.0 to the inner-sphere surface complexes at pH 8.0. For the Ni(II) sorption in the binary-solute system, the coexisting Cu(II) induces the formation of the inner-sphere complexes at pH 6.0. In contrast, Ni(II) is adsorbed on montmorillonite via the formation of Ni phyllosilicate co-precipitate/α-Ni(OH)2(s) precipitate at pH 8.0. The selective sequence

  7. Extraction and separation of Pd(II), Pt(IV), Fe(III), Zn(II), Cu(II) and Ag(I) from hydrochloric acid solutions with selected cyanamides as novel extractants.

    PubMed

    Mowafy, E A; Aly, H F

    2007-10-22

    Three structurally related novel extractants namely: N,N-dihexylcyanamide (DHCY), N,N-di(2-ethylhexyl)cyanamide (DEHCY) and N,N-di-octylcyanamide (DOCY) were synthesized in our laboratory and characterized by different techniques. The general method for synthesizing these extractants was based on the reaction of relevant secondary amines with cyanogen bromide in presence of sodium acetate anhydride. Their extracting ability in toluene as a diluent for Pd(II), Pt(IV), Fe(III), Zn(II), Cu(II) and Ag(I) from hydrochloric acid media has been studied. The extraction of hydrochloric acid was studied also. Pd(II) was strongly extracted by these extractants at low hydrochloric acid concentrations and the extraction decreased with increasing hydrochloric acid concentration while the reverse was obtained in the extraction of Pt(IV), Fe(III) and Zn(II). Under similar extraction conditions Cu(II) and Ag(I) were found poorly extracted. Hydrochloric acid was extracted only in its high concentration region. A systematic investigation has been carried out on the extraction of Pd(II) using two of the synthesized extractants. Pd(II) was extracted as a solvated complex with the composition, metal:chloride ion:extractant=1:2:2. The extracted species were studied also using IR spectra.

  8. The vibrational spectra of the Ni(II) and Cu(II) complexes with oxamic hydrazide

    NASA Astrophysics Data System (ADS)

    Quaeyhaegens, Frank; Hofmans, Hendrik; Desseyn, H. O.

    The infrared-, Raman- and u.v./vis spectra as well as the thermal analysis ofthe Ni(II)and Cu(II) complexes with oxamic hydrazide (H 2NCOCONHNH 2) are discussed. We assume 2/1 planar complexes and a coordination via the four amide nitrogen atoms as visualised in Fig. 1.

  9. Spectral, IR and magnetic studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes with pyrrole-2-carboxyaldehyde thiosemicarbazone (L).

    PubMed

    Chandra, Sulekh; Kumar, Anil

    2007-11-01

    Mn(II), Co(II), Ni(II) and Cu(II) complexes are synthesized with thiosemicarbazone (L) derived from pyrrole-2-carboxyaldehyde. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurement, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO indicates that the complexes are non-electrolyte except Co(L)2(NO3)2 and Ni(L)2(NO3)2 complexes which are 1:2 electrolyte. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry may be assigned for Mn(II), Co(II) and Ni(II) complexes except Co(L)2(NO3)2 and Ni(L)2(NO3)2 which are of tetrahedral geometry. A tetragonal geometry may be suggested for Cu(II) complexes.

  10. Ni(II), Pd(II) and Pt(II) complexes of (1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol. Structural, spectroscopic, biological, cytotoxicity, antioxidant and DNA binding

    NASA Astrophysics Data System (ADS)

    Gaber, M.; El-Ghamry, H. A.; Fathalla, S. K.

    2015-03-01

    Metal complexes of the general formula [ML(H2O)Cl]nH2O; n = 1 for M = Ni and Pt and n = 2 for M = Pd, L = Schiff base (HL) derived from the condensation of 3-amino-1,2,4-triazole and 2-hydroxy-1-naphthaldehyde, were prepared. The synthesized ligand and its metal complexes were characterized on the basis of elemental analyses, spectral and magnetic studies as well as thermal analysis. The IR spectra revealed that the ligand is coordinated to the metal ions in bidentate manner via the N-atom of the azomethine group and the phenolic OH group. Square planar geometry was proposed for Pd(II) and Pt(II) complexes and tetrahedral for Ni(II) complex. The ligand and its metal complexes were screened against the sensitive organisms Escherichia coli as Gram-negative bacteria, Staphylococcus aureus as Gram-positive bacteria, Aspergillus flavus and Candida albicans as fungi. Moreover, the anticancer activity of the ligand and its metal complexes was evaluated in liver carcinoma (HEPG2) cell line. The results obtained indicated that the Schiff base ligand is more effective than its metal complexes towards the tested cell line. Ni(II), Pd(II) and Pt(II) complexes as well as the free Schiff base ligand were tested for their antioxidant activities. The DNA-binding properties of the studied complexes have been investigated by electronic absorption and viscosity measurements.

  11. Ni(II), Pd(II) and Pt(II) complexes of (1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol. Structural, spectroscopic, biological, cytotoxicity, antioxidant and DNA binding.

    PubMed

    Gaber, M; El-Ghamry, H A; Fathalla, S K

    2015-03-15

    Metal complexes of the general formula [ML(H2O)Cl]nH2O; n=1 for M=Ni and Pt and n=2 for M=Pd, L=Schiff base (HL) derived from the condensation of 3-amino-1,2,4-triazole and 2-hydroxy-1-naphthaldehyde, were prepared. The synthesized ligand and its metal complexes were characterized on the basis of elemental analyses, spectral and magnetic studies as well as thermal analysis. The IR spectra revealed that the ligand is coordinated to the metal ions in bidentate manner via the N-atom of the azomethine group and the phenolic OH group. Square planar geometry was proposed for Pd(II) and Pt(II) complexes and tetrahedral for Ni(II) complex. The ligand and its metal complexes were screened against the sensitive organisms Escherichia coli as Gram-negative bacteria, Staphylococcus aureus as Gram-positive bacteria, Aspergillus flavus and Candida albicans as fungi. Moreover, the anticancer activity of the ligand and its metal complexes was evaluated in liver carcinoma (HEPG2) cell line. The results obtained indicated that the Schiff base ligand is more effective than its metal complexes towards the tested cell line. Ni(II), Pd(II) and Pt(II) complexes as well as the free Schiff base ligand were tested for their antioxidant activities. The DNA-binding properties of the studied complexes have been investigated by electronic absorption and viscosity measurements.

  12. Synthesis, spectral and theoretical studies of Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2'-hydroxynaphthaline.

    PubMed

    Gaber, Mohamed; El-Ghamry, Hoda; Atlam, Faten; Fathalla, Shaimaa

    2015-02-25

    Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2'-hydroxynaphthaline have been isolated and characterized by elemental analysis, IR, (1)H NMR, EI-mass, UV-vis, molar conductance, magnetic moment measurements and thermogravimetric analysis. The molar conductance values indicated that the complexes are non-electrolytes. The magnetic moment values of the complexes displayed diamagnetic behavior for Pd(II) and Pt(II) complexes and tetrahedral geometrical structure for Ni(II) complex. From the bioinorganic applications point of view, the interaction of the ligand and its metal complexes with CT-DNA was investigated using absorption and viscosity titration techniques. The Schiff-base ligand and its metal complexes have also been screened for their antimicrobial and antitumor activities. Also, theoretical investigation of molecular and electronic structures of the studied ligand and its metal complexes has been carried out. Molecular orbital calculations were performed using DFT (density functional theory) at B3LYP level with standard 6-31G(d,p) and LANL2DZ basis sets to access reliable results to the experimental values. The calculations were performed to obtain the optimized molecular geometry, charge density distribution, extent of distortion from regular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), Mulliken atomic charges, reactivity index (ΔE), dipole moment (D), global hardness (η), softness (σ), electrophilicity index (ω), chemical potential and Mulliken electronegativity (χ).

  13. Synthesis, spectral and theoretical studies of Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2‧-hydroxynaphyhaline

    NASA Astrophysics Data System (ADS)

    Gaber, Mohamed; El-Ghamry, Hoda; Atlam, Faten; Fathalla, Shaimaa

    2015-02-01

    Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2‧-hydroxynaphthaline have been isolated and characterized by elemental analysis, IR, 1H NMR, EI-mass, UV-vis, molar conductance, magnetic moment measurements and thermogravimetric analysis. The molar conductance values indicated that the complexes are non-electrolytes. The magnetic moment values of the complexes displayed diamagnetic behavior for Pd(II) and Pt(II) complexes and tetrahedral geometrical structure for Ni(II) complex. From the bioinorganic applications point of view, the interaction of the ligand and its metal complexes with CT-DNA was investigated using absorption and viscosity titration techniques. The Schiff-base ligand and its metal complexes have also been screened for their antimicrobial and antitumor activities. Also, theoretical investigation of molecular and electronic structures of the studied ligand and its metal complexes has been carried out. Molecular orbital calculations were performed using DFT (density functional theory) at B3LYP level with standard 6-31G(d,p) and LANL2DZ basis sets to access reliable results to the experimental values. The calculations were performed to obtain the optimized molecular geometry, charge density distribution, extent of distortion from regular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), Mulliken atomic charges, reactivity index (ΔE), dipole moment (D), global hardness (η), softness (σ), electrophilicity index (ω), chemical potential and Mulliken electronegativity (χ).

  14. Biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions by cross-linked metal-imprinted chitosans with epichlorohydrin.

    PubMed

    Chen, Chia-Yun; Yang, Cheng-Yu; Chen, Arh-Hwang

    2011-03-01

    Cross-linked metal-imprinted chitosan microparticles were prepared from chitosan, using four metals (Cu(II), Zn(II), Ni(II), and Pb(II)) as templates, and epichlorohydrin as the cross-linker. The microparticles were characterized by Fourier transform infrared spectroscopy, solid state (13)C nuclear magnetic resonance spectroscopy, and energy-dispersive X-ray spectroscopy. They were used for comparative biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions in an aqueous solution. The results showed that the sorption capacities of Cu(II), Zn(II), Ni(II), and Pb(II) on the templated microparticles increased from 25 to 74%, 13 to 46%, 41 to 57%, and 12 to 43%, respectively, as compared to the microparticles without metal ion templates. The dynamic study showed that the sorption process followed the second-order kinetic equation. Three sorption models, Langmuir, Freundlich, and Dubinin-Radushkevich, were applied to the equilibrium isotherm data. The result showed that the Langmuir isotherm equation best fitted for monolayer sorption processes. Furthermore, the microparticles can be regenerated and reused for the metal removal.

  15. Polymeric material prepared from Schiff base based on O-carboxymethyl chitosan and its Cu(II) and Pd(II) complexes

    NASA Astrophysics Data System (ADS)

    Baran, Talat; Menteş, Ayfer

    2016-07-01

    In this study, a new eco-friendly Schiff base based on O-carboxymethyl chitosan ([OCMCS-7a]) and its copper(II) and palladium(II) complexes were synthesized. Characterizations of [OCMCS-7a] and its metal complexes were conducted using FTIR, 1H NMR, 13C NMR, TG/DTG, XRD, SEM-EDAX, ICP, UV-VIS, GC-MS, elemental analysis, magnetic moment and molar conductivity measurements. The degree of substitution (DS) of [OCMCS-7a] was determined by elemental analysis to be 0.44. It was shown by the solubility test that [OCMCS-7a] was completely soluble in water. Surface images of chitosan, [OCMCS-7a] and its Cu(II) and Pd(II) complexes were investigated using the SEM-EDAX technique. Their thermal behaviors and crystallinities of the synthesized complexes were determined by TG/DTG and X-ray powder diffraction techniques, respectively. The metal contents of the obtained complexes were determined using an ICP-OES instrument. From the analyses, it was noted that the thermal stabilities and crystallinities of [OCMCS-7a] and its complexes decreased compared to chitosan. As a consequence of surface screening, it was also noted that the surface structure of the chitosan was smoother than that of the obtained compounds.

  16. Synthesis and studies on Cu(II), Co(II), Ni(II) complexes of Knoevenagel β-diketone ligands

    NASA Astrophysics Data System (ADS)

    Sumathi, S.; Tharmaraj, P.; Sheela, C. D.; Anitha, C.

    2012-11-01

    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, 1H NMR, Mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are non-electrolytic in nature. Spectroscopic and other analytical data of the complexes suggest octahedral geometry for other metal(II) complexes. The redox behavior 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 the bacteria Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus as well as the fungus Candida albicans by well diffusion method. The zone of inhibition value indicates that the most of 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 (L1-L3) was found to be considerable effect than that of urea and KDP (potassium dihydrogen phosphate).

  17. Synthesis, structural characterization, thermal and electrochemical studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes containing thiazolylazo ligands

    NASA Astrophysics Data System (ADS)

    Chavan, S. S.; Sawant, V. A.

    2010-02-01

    Some thiazolylazo derivatives and their metal complexes of the type [M(L)(H 2O)Cl]; M = Mn(II), Co(II), Ni(II), Cu(II) and L = 6-(2'-thiazolylazo)-2-mercapto-quinazolin-4-one (HL 1), 6-(4'-phenyl-2'-thiazolylazo)-2-mercapto-quinazolin-4-one (HL 2), 6-(2'-thiazolylazo)-2-mercapto-3-( m-tolyl)-quinazolin-4-one (HL 3) and 6-(4'-phenyl-2'-thiazolylazo)-2-mercapto-3-( m-tolyl)-quinazolin-4-one (HL 4) have been prepared. All the complexes were characterized on the basis of elemental analysis, molar conductance, magnetic moment, IR, UV-vis, ESR, TG-DTA and powder X-ray diffraction studies. IR spectra of these complexes reveal that the complex formation occurred through thiazole nitrogen, azo nitrogen, imino nitrogen and sulfur atom of the ligands. On the basis of electronic spectral data and magnetic susceptibility measurement octahedral geometry has been proposed for the Mn(II), Co(II) and Ni(II) complexes and distorted octahedral geometry for the Cu(II) complexes. Electrochemical behavior of Ni(II) complexes exhibit quasireversible oxidation corresponding to Ni(III)/Ni(II) couple along with ligand reduction. X-ray diffraction study is used to elucidate the crystal structure of the complexes.

  18. The Co(II), Ni(II) and Cu(II) complexes with herbicide 2,4-dichlorophenoxyacetic acid - Synthesis and structural studies

    NASA Astrophysics Data System (ADS)

    Drzewiecka-Antonik, Aleksandra; Ferenc, Wiesława; Wolska, Anna; Klepka, Marcin T.; Cristóvão, Beata; Sarzyński, Jan; Rejmak, Paweł; Osypiuk, Dariusz

    2017-01-01

    The Co(II), Ni(II) and Cu(II) complexes with herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) were synthesized and structurally characterized. The geometry of metal-ligand interaction was refined using XAFS and DFT studies. The Co(2,4-D)2·6H2O and Ni(2,4-D)2·4H2O complexes have octahedral geometry with two carboxylate groups of 2,4-D anions and four water molecules in the coordination sphere. The square planar geometry around metal cations formed by the carboxylate groups from two monodentate ligands and two water molecules, is observed for Cu(2,4-D)2·4H2O complex. In the recrystallized Ni(II) complex dinuclear 'Chinese lantern' structures with bridging carboxylate groups of 2,4-D were observed.

  19. Synthesis, molecular structures and phase transition studies on benzothiazole-cored Schiff bases with their Cu(II) and Pd(II) complexes: Crystal structure of (E)-6-methoxy-2-(4-octyloxy-2-hydroxybenzylideneamino)benzothiazole

    NASA Astrophysics Data System (ADS)

    Yeap, Guan-Yeow; Heng, Boon-Teck; Faradiana, Nur; Zulkifly, Raihana; Ito, Masato M.; Tanabe, Makoto; Takeuchi, Daisuke

    2012-03-01

    Two new homologous series of Cu(II) and Pd(II) complexes with benzothiazole-cored Schiff bases have been synthesised with the aim to study the mesomorphic and thermal properties of ligands upon formation of metal complexes. The molecular structure of title compounds were elucidated with the employment of FT-IR, 1D and 2D FT-NMR spectroscopic techniques. Mesomorphic and thermal behaviour of title compounds have been investigated by differential scanning calorimetry and polarising optical microscope. All the ligands are nematogenic but the corresponding Cu(II) and Pd(II) complexes crystallised in ordinary solid. The conformation of 6-methoxy-2-(4-octyloxy-2-hydroxy-benzylideneamino)benzothiazole was determined by single crystal X-ray diffraction analysis of which the title compound favours more stable (E)-6-methoxy-2-(4-octyloxy-2-hydroxybenzylideneamino)benzothiazole. Crystal structure of the title compound also revealed that the bond length of Cdbnd N (1.303 Å) in the benzothiazole rings very close to that in the exocyclic Cdbnd N linkage (1.298 Å).

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

    PubMed Central

    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. PMID:23983672

  1. Synthesis, characterization and quantum chemical ab initio calculations of new dimeric aminocyclodiphosph(V)azane and its Co(II), Ni(II) and Cu(II) complexes.

    PubMed

    Alaghaz, Abdel-Nasser M A; Al-Sehemi, Abdullah G; El-Gogary, Tarek M

    2012-09-01

    The complexes of type [M(2)LCl(2)] in which M=Co(II), Ni(II) and Cu(II) ions and L are 1,3-o-pyridyl-2,4-dioxo-2',4'-bis(3-benzo[d]thiazol-2-yl-2-iminothiophene) cyclodiphosph(V)azane, were prepared and their structures were characterized by different physical techniques (IR, UV-Vis, (1)H NMR, (31)P NMR, mass, TGA, DTA, XRD, SEM, magnetic moment and electrical conductance measurements). Ab initio calculations at the level of DFT B3LYP/6-31G(d) were utilized to find the optimum geometry of the ligand. Spectral characterization of the ligand was simulated using DT-DFT method. Infrared spectra of the complexes indicate deprotonation and coordination of the imine NH. It also confirms that nitrogen atoms of the pyridine group and thiazole group contribute to the complexation. NBO natural charges were computed and discussed in the light of coordination centers. Electronic spectra and magnetic susceptibility measurements as well as quantum chemical calculations reveal square planar geometry for Cu(II) and Ni(II) complexes and tetrahedral geometry for Co(II) complex. The elemental analyses and mass spectral data have justified the M(2)LCl(2) composition of complexes.

  2. Synthesis, molecular docking and evaluation of antifungal activity of Ni(II), Co(II) and Cu(II) complexes of porphyrin core macromolecular ligand.

    PubMed

    Singh, Urvashi; Malla, Ali Mohammad; Bhat, Imtiyaz Ahmad; Ahmad, Ajaz; Bukhari, Mohd Nadeem; Bhat, Sneha; Anayutullah, Syed; Hashmi, Athar Adil

    2016-04-01

    Porphyrin core dendrimeric ligand (L) was synthesized by Rothemund synthetic route in which p-hydroxy benzaldehyde and pyrrole were fused together. The prepared ligand was complexed with Ni(II), Cu(II) and Co(II) ions, separately. Both the ligand and its complexes were characterized by elemental analysis and spectroscopic studies (FT-IR, UV-Vis, (1)HNMR). Square planar geometries were proposed for Cu(II), Ni(II) and Co(II) ions in cobalt, Nickel and copper complexes, respectively on the basis of UV-Vis spectroscopic data. The ligand and its complex were screened on Candida albicans (ATCC 10231), Aspergillus fumigatus (ATCC 1022), Trichophyton mentagrophytes (ATCC 9533) and Pencillium marneffei by determining MICs and inhibition zones. The activity of the ligand and its complexes was found to be in the order: CuL ˃ CoL ≈ NiL ˃ L. Detection of DNA damage at the level of the individual eukaryotic cell was observed by commet assay. Molecular docking technique was used to understand the ligand-DNA interactions. From docking experiment, we conclude that copper complex interacts more strongly than rest two.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: Synthesis and spectral approach

    NASA Astrophysics Data System (ADS)

    Patil, Sangamesh A.; Prabhakara, Chetan T.; Halasangi, Bhimashankar M.; Toragalmath, Shivakumar S.; Badami, Prema S.

    2015-02-01

    The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, 1H NMR, 13C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

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

    PubMed

    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·2H2O 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.

  6. DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: synthesis and spectral approach.

    PubMed

    Patil, Sangamesh A; Prabhakara, Chetan T; Halasangi, Bhimashankar M; Toragalmath, Shivakumar S; Badami, Prema S

    2015-02-25

    The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

  7. Synthesis, characterization and biological activity of Cu(II), Ni(II) and Zn(II) complexes of biopolymeric Schiff bases of salicylaldehydes and chitosan.

    PubMed

    de Araújo, Eliene Leandro; Barbosa, Hellen Franciane Gonçalves; Dockal, Edward Ralph; Cavalheiro, Éder Tadeu Gomes

    2017-02-01

    Schiff bases have been prepared from biopolymer chitosan and salicylaldehyde, 5-methoxysalicylaldehyde, and 5-nitrosalicylaldehyde. Ligands were synthesized in a 1:1.5mol ratio, and their Cu(II), Ni(II) and Zn(II) complexes in a 1:1mol ratio (ligand:metal). Ligands were characterized by (1)H NMR and FTIR, resulting in degrees of substitution from 43.7 to 78.7%. Complexes were characterized using FTIR, electronic spectra, XPRD. The compounds were confirmed by the presence of an imine bond stretching in the 1630-1640cm(-1) and νMetal-N and νMetal-O at <600cm(-1). Electronic spectra revealed that both Cu(II) and Ni(II) complexes present a square plane geometry. The crystallinity values were investigated by X-ray powder diffraction. Thermal behavior of all compounds was evaluated by TGA/DTG and DTA curves with mass losses related to dehydration and decomposition, with characteristic events for ligand and complexes. Schiff base complexes presented lower thermal stability and crystallinity than the starting chitosan. Residues were the metallic oxides as confirmed by XPRD, whose amounts were used in the calculation of the percentage of complexed metal ions. Surface morphologies were analyzed with SEM-EDAX. Preliminary cytotoxicity tests were performed using MTT assay with HeLa cells. Despite the differences in solubility, the free bases presented relatively low toxicity.

  8. Synthesis, spectroscopic, anticancer, antibacterial and antifungal studies of Ni(II) and Cu(II) complexes with hydrazine carboxamide, 2-[3-methyl-2-thienyl methylene

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Vandana; Kumar, Suresh

    2015-01-01

    Schiff's base ligand(L) hydrazine carboxamide, 2-[3-methyl-2-thienyl methylene] and its metal complexes have been synthesized and characterized by elemental analysis, molar conductance, various spectroscopic techniques such as electronic, IR, 1H NMR, mass, EPR. Molar conductance of complexes in DMF solution corresponds to non-electrolyte. Complexes have general composition [M(L)2X2], where M = Ni(II) and Cu(II), X = Cl-, NO3-, CH3COO- and ½SO42-. On the basis of above spectral studies, an octahedral geometry has been assigned for Ni(II) complexes and tetragonal geometry for Cu(II) complexes except [Cu(L)2SO4] which possesses five coordinated trigonal bipyramidal geometry. These metal complexes were also tested for their anticancer, antibacterial and antifungal activities to assess their inhibition potential. Anticancer activity of ligand and its metal complexes were evaluated using SRB fluorometric assay and Adriamycin (ADR) was applied as positive control. Schiff's base ligand and its metal complexes were screened for their antibacterial and antifungal activity against Escherichia coli, Bacillus cereus and Aspergillus niger, Aspergillus flavus, respectively. Kirby-Bauer single disk susceptibility test was used for antibacterial activity and well diffusion method for antifungal activity of the compounds on the used fungi.

  9. Synthesis and characterization of transition metal 2,6-pyridinedicarboxylic acid derivatives, interactions of Cu(II) and Ni(II) complexes with DNA in vitro

    NASA Astrophysics Data System (ADS)

    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.

  10. Synthesis, spectral characterization and thermal studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-amino benzoic acid- and 2-hydroxy benzoic acid thiophen-2-ylmethylene hydrazide

    NASA Astrophysics Data System (ADS)

    Singh, Vinod P.; Singh, Pooja

    2013-03-01

    A series of metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 2-amino benzoic acid thiophen-2-ylmethylene hydrazide (Habth) and 2-hydroxy benzoic acid thiophen-2-ylmethylene hydrazide (Hhbth) have been synthesized. The complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, electronic, IR, NMR, ESR spectra and thermal studies (TGA and DTA). Molecular structure of the Habth ligand was determined by single crystal X-ray diffraction technique. Habth acts as a monobasic bidentate ligand in all its complexes bonding through a deprotonated Csbnd O- and lbond2 Cdbnd Nsbnd groups whereas, Hhbth acts as a monobasic bidentate in its Co(II) and Ni(II) complexes, bonding through a deprotonated Csbnd O- and lbond2 Cdbnd Nsbnd groups and as monobasic tridentate in Cu(II) and Zn(II) complexes bonding through lbond2 Cdbnd O, lbond2 Cdbnd Nsbnd and deprotonated (Csbnd O)- groups with the metal ion. Electronic spectra suggest a square planar geometry for Co(II), Ni(II) and Cu(II) complexes of Habth and Co(II) and Ni(II) complexes of Hhbth. However, the Cu(II) and Zn(II) complexes of Hhbth have octahedral geometry. The ESR spectra of Cu(II) complex of Hhbth in the solid state and in DMSO frozen solution show axial signals and suggest the presence of unpaired electron in d orbital of Cu(II). The Cu(II) complex of Habth in solid state shows isotropic signal, whereas, axial signal in DMSO frozen solution in the range of tetragonally distorted octahedral geometry due to interactions of DMSO molecules at axial positions. Thermal studies of some of the metal complexes show a multi-step decomposition pattern of bonded ligands in the complex.

  11. Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate Schiff base derived from vanillin and DL-α-aminobutyric acid

    NASA Astrophysics Data System (ADS)

    Nair, M. Sivasankaran; Joseyphus, R. Selwin

    2008-09-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from vanillin and DL-α-aminobutyric acid were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements, powder XRD and biological activity. The analytical data show the composition of the metal complex to be [ML(H 2O)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. IR results demonstrate the tridentate binding of the Schiff base ligand involving azomethine nitrogen, phenolic oxygen and carboxylato oxygen atoms. The IR data also indicate the coordination of a water molecule with the metal ion in the complex. The electronic spectral measurements show that Co(II) and Ni(II) complexes have tetrahedral geometry, while Cu(II) complex has square planar geometry. The powder XRD studies indicate that Co(II) and Cu(II) complexes are amorphous, whereas Ni(II) and Zn(II) complexes are crystalline in nature. Magnetic measurements show that Co(II), Ni(II) and Cu(II) complexes have paramagnetic behaviour. Antibacterial results indicated that the metal complexes are more active than the ligand.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Design, synthesis and characterization of macrocyclic ligand based transition metal complexes of Ni(II), Cu(II) and Co(II) with their antimicrobial and antioxidant evaluation

    NASA Astrophysics Data System (ADS)

    Gull, Parveez; Malik, Manzoor Ahmad; Dar, Ovas Ahmad; Hashmi, Athar Adil

    2017-04-01

    Three new complexes Ni(II), Cu(II) and Co(II) were synthesized of macrocyclic ligand derived from 1, 4-dicarbonyl-phenyl-dihydrazide and O-phthalaldehyde in the ratio of 2:2. The synthesized compounds were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, FTIR, UV-Vis., Mass and 1H NMR spectral studies. The electronic spectra of the metal complexes indicate a six coordinate octahedral geometry of the central metal ion. These metal complexes and the ligand were evaluated for antimicrobial activity against bacteria (E. coli, B. subtilis, S. aureus) and fungi (A. niger, A. flavus, C. albicans) and compared against standard drugs chloramphenicol and nystatin respectively. In addition, the antioxidant activity of the compounds was also investigated through scavenging effect on DPPH radicals.

  14. Synthesis, characterization, in vitro antimicrobial and DNA cleavage studies of Co(II), Ni(II) and Cu(II) complexes with ONOO donor coumarin Schiff bases

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    A series of Co(II), Ni(II) and Cu(II) complexes have been synthesized with Schiff bases derived from 2-hydroxy-1-naphthaldehyde and 2-oxo-2H-chromene-3-carbohydrazide/6-bromo-2-oxo-2H-chromene-3-carbohydrazide. The chelation of the complexes has been proposed in the light of analytical, spectral (IR, UV-Vis, 1H NMR, ESR, FAB-mass and fluorescence), magnetic and thermal studies. The measured molar conductance values indicate that, the complexes are non-electrolytic in nature. The redox behavior of the complexes was investigated with electrochemical method by using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial ( Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi) and antifungal activities ( Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The DNA cleavage is studied by agarose gel electrophoresis method.

  15. Synthesis, characterization, equilibrium study and biological activity of Cu(II), Ni(II) and Co(II) complexes of polydentate Schiff base ligand.

    PubMed

    El-Sherif, Ahmed A; Shehata, Mohamed R; Shoukry, Mohamed M; Barakat, Mohammad H

    2012-10-01

    Schiff base ligand, 1,4-bis[(2-hydroxybenzaldehyde)propyl]piperazine (BHPP), and its Cu(II), Ni(II) and Co(II) metal complexes were synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance and spectral (IR and UV-vis) studies. The ground state of BHPP ligand was investigated using the BUILDER module of MOE. Metal complexes are formed in the 1:1 (M:L) ratio as found from the elemental analysis and found to have the general formula [ML]·nH(2)O, where M=Co(II), Ni(II) and Cu(II), L=BHPP. In all the studied complexes, the (BHPP) ligand behaves as a hexadentate divalent anion with coordination involving the two azomethine nitrogen's, the two nitrogen atoms of piperazine ring and the two deprotonated phenolic OH-groups. The magnetic and spectral data indicates octahedral geometry of metal(II) complexes. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. They were found to be more active against Gram-positive than Gram-negative bacteria. Protonation constants of (BHPP) ligand and stability constants of its Cu(2+), Co(2+) and Ni(2+) complexes were determined by potentiometric titration method in 50% DMSO-water solution at ionic strength of 0.1 M sodium nitrate. It has been observed that the protonated Schiff base ligand (BHPP) have four protonation constants. The divalent metal ions Cu(2+), Ni(2+) and Co(2+) form 1:1 complexes.

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

    PubMed

    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.

  17. Experimental and computational study on 2,2'-[(1E,2E)-hydrazine-1,2-diylidenedi(1E)eth-1-yl-1-ylidene]diphenol and its Ni(II), Pt(II), Pd(II) complexes.

    PubMed

    Alyar, Saliha; Özbek, Neslihan; Yıldırım, Sema Öztürk; Ide, Semra; Butcher, Ray J

    2014-09-15

    2,2'-[(1E,2E)-hydrazine-1,2-diylidenedi(1E)eth-1-yl-1-ylidene]diphenol and its dimeric, binuclear Ni(II), Pd(II) and Pt(II) metal complexes were synthesized. Hydrazine derivative and its complexes were characterized by elemental analyses, LC-MS, IR, electronic spectra, (1)H and (13)C NMR spectra, conductivity and magnetic measurements. 1H and 13C shielding tensors for crystal structure were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments were performed at B3LYP/6-311++G(d,p) theory level combined with scaled quantum mechanics force field (SQMFF) methodology. The antibacterial activities of synthesized compounds were studied against some Gram-positive and Gram-negative bacteria by using the microdilution and disk diffusion method. As the antibacterial activity results evidently show, the compound possessed a broad spectrum of activity against the tested bacteria.

  18. 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

    NASA Astrophysics Data System (ADS)

    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.

  19. Synthesis, characterization, and antioxidant/cytotoxic activity of new chromone Schiff base nano-complexes of Zn(II), Cu(II), Ni(II) and Co(II)

    NASA Astrophysics Data System (ADS)

    Saif, M.; El-Shafiy, Hoda F.; Mashaly, Mahmoud M.; Eid, Mohamed F.; Nabeel, A. I.; Fouad, R.

    2016-08-01

    A chromone Schiff base complexes of Zn(II) (1), Cu(II) (2), Ni(II) (3) and Co(II) (4) were successfully prepared in nano domain with crystalline or amorphous structures. The spectroscopic data revealed that the Schiff base ligand behaves as a monoanionic tridentate ligand. The metal complexes exhibited octahedral geometry. Transmission electron microscope (TEM) analysis showed that Cu(II) complex have aggregated nanospheres morphology. The obtained nano-complexes were tested as antioxidant and antitumor agents. The H2L and its Cu(II) complex (2) were found to be more potent antioxidant (IC50(H2L) = 0.93 μM; IC50(Cu(II) complex) = 1.1 μM than standard ascorbic acid (IC50 = 2.1 μM) as evaluated by DPPH• method. The H2L and its complexes (1-4) were tested for their in vitro cytotoxicity against Ehrlich Ascites Carcinoma cell line (EAC). The Cu(II) nano-complex (2) effectively inhibited EAC growth with IC50 value of 47 μM in comparison with its parent compound and other prepared complexes. The high antioxidant activity and antitumor activity of Cu(II) nano-complex (2) were attributed to their chemical structure, Cu(II) reducing capacity, and nanosize property. The toxicity test on mice showed that Zn(II) (1) and Cu(II) (2) nano-complex have lower toxicity than the standard cis-platin.

  20. Removal of Cu(II) and Ni(II) using cellulose extracted from sisal fiber and cellulose-g-acrylic acid copolymer.

    PubMed

    Hajeeth, T; Vijayalakshmi, K; Gomathi, T; Sudha, P N

    2013-11-01

    The extraction of cellulose from sisal fiber was done initially using the steam explosion method. The batch adsorption studies were conducted using the cellulose extracted from the sisal fiber and cellulose-g-acrylic acid as an adsorbent for the removal of Cu(II) and Ni(II) metal ions from aqueous solution. The effect of sorbent amount, agitation period and pH of solution that influence sorption capacity were investigated. From the observed results, it was evident that the adsorption of metal ions increases with the increase in contact time and adsorbent dosage. The optimum pH was found to be 5.0 for the removal of copper(II) and nickel(II) for both the extracted cellulose and cellulose-g-acrylic acid copolymer. The adsorption data were modeled using Langmuir and Freundlich isotherms. The experimental results of the Langmuir, Freundlich isotherms revealed that the adsorption of Cu(II) and nickel(II) ion onto cellulose extracted from the sisal fiber and cellulose-g-acrylic acid copolymer was found to fit well with Freundlich isotherm. The kinetics studies show that the adsorption follows the pseudo-second-order kinetics. From the above results, it was concluded that the cellulose-g-acrylic acid copolymer was found to be an efficient adsorbent.

  1. Spectroscopic and fluorescence studies on Mn(II), Co(II), Ni(II) and Cu(II) complexes with NO donor fluorescence dyes

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Metwaly, Nashwa M.

    2011-10-01

    The reactions of the two common dyes [2TMPACT and 4PENI] with Mn(II), Co(II), Ni(II) and Cu(II) ions were done. All the isolated complexes have been characterized by physicochemical and spectroscopic techniques. The IR data reflect the bidentate mode of 2TMPACT towards the mononuclear complex [Mn(II)] even its tetradentate in binuclear complexes [Co(II) and Cu(II)]. However, the bidentate mode is the only behavior of 4PENI ligand towards each metal ion in its mononuclear complexes. The UV-vis spectral analysis beside the magnetic moment measurements are proposed different geometries concerning each metal ions with the two ligands under investigation, as the Mn(II)-2TMPACT complex is an octahedral but Mn(II)-4PENI is a tetrahedral geometry. All the synthesized compounds are thermogravimetrically investigated. The proposed thermal decomposition was discussed for each compound with each step as well as, the kinetic parameters were calculated for all preferrible decomposition steps. The mass spectroscopy tool was used to emphasis on the suitable molecular formula proposed and the fragmentation patterns were displayed. The fluorescence properties of the synthesized ligands and their complexes were studied in DMSO at room temperature.

  2. Spectroscopic and fluorescence studies on Mn(II), Co(II), Ni(II) and Cu(II) complexes with NO donor fluorescence dyes.

    PubMed

    Refat, Moamen S; el-Metwaly, Nashwa M

    2011-10-15

    The reactions of the two common dyes [2TMPACT and 4PENI] with Mn(II), Co(II), Ni(II) and Cu(II) ions were done. All the isolated complexes have been characterized by physicochemical and spectroscopic techniques. The IR data reflect the bidentate mode of 2TMPACT towards the mononuclear complex [Mn(II)] even its tetradentate in binuclear complexes [Co(II) and Cu(II)]. However, the bidentate mode is the only behavior of 4PENI ligand towards each metal ion in its mononuclear complexes. The UV-vis spectral analysis beside the magnetic moment measurements are proposed different geometries concerning each metal ions with the two ligands under investigation, as the Mn(II)-2TMPACT complex is an octahedral but Mn(II)-4PENI is a tetrahedral geometry. All the synthesized compounds are thermogravimetrically investigated. The proposed thermal decomposition was discussed for each compound with each step as well as, the kinetic parameters were calculated for all preferrible decomposition steps. The mass spectroscopy tool was used to emphasis on the suitable molecular formula proposed and the fragmentation patterns were displayed. The fluorescence properties of the synthesized ligands and their complexes were studied in DMSO at room temperature.

  3. Synthesis, spectroscopic characterization, molecular modeling and antimicrobial activities of Mn(II), Co(II), Ni(II), Cu(II) complexes containing the tetradentate aza Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Ruchi

    2013-02-01

    Mn(II), Co(II), Ni(II), and Cu(II) complexes with a tetradentate macrocyclic ligand [1.2.5.6tetraoxo-3,4,7,8tetraaza-(1,2,3,4,5,6,7,8)tetrabenzene(L)] were synthesized and characterized by elemental analysis, molar conductance measurements, mass, nmr, i.r., electronic and e.p.r. spectral studies. All the complexes are non electrolytes in nature and may be formulated as [M(L)X2] [where, M = Mn(II), Co(II), Ni(II), Cu(II) and X = Cl-, CH3COO-]. On the basis of i.r., electronic and e.p.r. spectral studies a distorted octahedral geometry has been assigned for all complexes. The antimicrobial activities and LD50 values of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against two different species of bacteria and plant pathogenic fungi.

  4. Dehydrogenation of ammonia-borane by cationic Pd(II) and Ni(II) complexes in a nitromethane medium: hydrogen release and spent fuel characterization.

    PubMed

    Kim, Sung-Kwan; Hong, Sung-Ahn; Son, Ho-Jin; Han, Won-Sik; Michalak, Artur; Hwang, Son-Jong; Kang, Sang Ook

    2015-04-28

    A highly electrophilic cationic Pd(II) complex, [Pd(MeCN)4][BF4]2 (1), brings about the preferential activation of the B-H bond in ammonia-borane (NH3·BH3, AB). At room temperature, the reaction between 1 in CH3NO2 and AB in tetraglyme leads to Pd nanoparticles and formation of spent fuels of the general formula MeNHxBOy as reaction byproducts, while 2 equiv. of H2 is efficiently released per AB equiv. at room temperature within 60 seconds. For a mechanistic understanding of dehydrogenation by 1, the chemical structures of spent fuels were intensely characterized by a series of analyses such as elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), solid state magic-angle-spinning (MAS) NMR spectra ((2)H, (13)C, (15)N, and (11)B), and cross polarization (CP) MAS methods. During AB dehydrogenation, the involvement of MeNO2 in the spent fuels showed that the mechanism of dehydrogenation catalyzed by 1 is different from that found in the previously reported results. This AB dehydrogenation derived from MeNO2 is supported by a subsequent digestion experiment of the AB spent fuel: B(OMe)3 and N-methylhydroxylamine ([Me(OH)N]2CH2), which are formed by the methanolysis of the AB spent fuel (MeNHxBOy), were identified by means of (11)B NMR and single crystal structural analysis, respectively. A similar catalytic behavior was also observed in the AB dehydrogenation catalyzed by a nickel catalyst, [Ni(MeCN)6][BF4]2 (2).

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  6. Theoretical and experimental studies on three new coordination complexes of Co(II), Ni(II), and Cu(II) with 2,4-dichloro-6-{(E)-[(5-chloro-2 sulfanylphenyl)imino]methyl}phenol Schiff base ligand.

    PubMed

    Kusmariya, Brajendra S; Mishra, A P

    2015-11-01

    Three mononuclear coordination complexes of Co(II), Ni(II), and Cu(II) have been synthesized from 2,4-dichloro-6-{(E)-[(5-chloro-2-sulfanylphenyl)imino]methyl}phenol ligand (H 2 L) obtained by simple condensation reaction of 3,5-dichloro-2-hydroxybenzaldehyde and 2-amino-4-chlorobenzenethiol and characterized by elemental analysis, spectral (FT-IR, electronic, and (1)H-NMR), molar conductance, thermal, SEM, PXRD, and fluorescence studies. The PXRD analysis and SEM-EDX micrographs show the crystalline nature of complexes. The domain size and the lattice strain of synthesized compounds have been determined according to Williamson-Hall plot. TG of the synthesized complexes illustrates the general decomposition pattern of the complexes. The ligand exhibits an interesting fluorescence property which is suppressed after complex formation. The Co(II) complex adopted a distorted octahedral configuration while Ni(II) and Cu(II) complexes showed square planar geometry around metal center. The geometry optimization, HOMO-LUMO, molecular electrostatic potential map (MEP), and spin density of synthesized compounds have been performed by density functional theory (DFT) method using B3LYP/6-31G and B3LYP/LANL2DZ as basis set. Graphical abstract Three new coordination complexes of Co(II), Ni(II) and Cu(II) with 2,4-dichloro-6-{(E)-[(5-chloro-2 sulfanylphenyl)imino]methyl}phenol Schiff base ligand.

  7. Effect of the competition of Cu(II) and Ni(II) on the kinetic and thermodynamic stabilities of Cr(III)-organic ligand complexes using competitive ligand exchange (EDTA).

    PubMed

    Cunha, Graziele da Costa; Goveia, Danielle; Romão, Luciane Pimenta Cruz; de Oliveira, Luciana Camargo

    2015-05-01

    The effect of competition of Cu(II) and Ni(II) on the kinetic stability of Cr(III) complexed with natural organic matter (NOM) was characterized using EDTA exchange with single-stage tangential-flow ultrafiltration. For a water sample from Serra de Itabaiana, 3% of spiked Cr(III) was exchanged, while for a sample from the Itapanhaú River, 7, 10, 10, and 21% was exchanged in experiments using Cr(III) alone and in combination with Cu(II), Ni(II), or Cu(II) + Ni(II), respectively. Times required to reach exchange equilibrium with EDTA were less than 360 min. The influence of competition from Ni(II) and Cu(II) on the availability of complexed Cr(III) was low, demonstrating preference of the ligand sites for Cr(III). This was correlated with sample humification, as confirmed by EPR and (13)C NMR analyses. Exchange efficiency was in the order Cu > Ni > Cr, and the process could be readily described by first order kinetics, with average rate constants of 0.35-0.37 h(-1).

  8. Synthesis, characterization and DNA binding/cleavage, protein binding and cytotoxicity studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes of aminonaphthoquinone.

    PubMed

    Kosiha, A; Parthiban, C; Elango, Kuppanagounder P

    2017-03-01

    The Co(II), Ni(II), Cu(II) and Zn(II) complexes of an aminonaphthoquinone ligand (L) have been prepared and characterized using analytical and spectral techniques. The structures of L and its Zn(II) complex are confirmed by single crystal X-ray diffraction study. The results indicate that Co(II), Ni(II) and Zn(II) complexes possess tetrahedral geometry while Cu(II) complex exhibits square planar structure. The interaction of L and its complexes with CT-DNA reveal that they could interact with CT-DNA through intercalation. The DNA cleavage studies of the L and its complexes indicate that the Cu(II) and Ni(II) complexes cleave the circular form of the DNA relatively to a greater extent than the other complexes. The results of the interaction of these compounds with bovine serum albumin (BSA) indicate that the complexes exhibit a strong binding to BSA over the L. The in vitro anticancer activities indicate that these compounds exhibit substantial activity against human breast (MCF7) and lung cancer (A549) cell lines. The characteristics of apoptosis in cell morphology have been observed using AO/EB and DAPI staining and the results suggest that an apoptotic mode of cell death with these compounds. The overall results and discussion indicate that coordination of metal ions with the ligand enhances the biological activity.

  9. Spectroscopic, magnetic and thermal studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes of 3-acetylcoumarin-isonicotinoylhydrazone and their antimicrobial and anti-tubercular activity evaluation

    NASA Astrophysics Data System (ADS)

    Hunoor, Rekha S.; Patil, Basavaraj R.; Badiger, Dayananda S.; Vadavi, Ramesh S.; Gudasi, Kalagouda B.; Chandrashekhar, V. M.; Muchchandi, I. S.

    2010-11-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes with a new heterocyclic Schiff base derived by the condensation of isonicotinoylhydrazide and 3-acetylcoumarin have been synthesized. 1H, 13C and 2D HETCOR NMR analyses confirm the formation of title compound and existence of the same in two isomeric forms. The metal complexes were characterized on the basis of various spectroscopic techniques like electronic, EPR, IR, 1H and 13C NMR studies, elemental analysis, magnetic properties and thermogravimetric analysis, and also by the aid of molar conductivity measurements. It is found that the Schiff base behaves as a monobasic tridentate ligand coordinating in the imidol form with 1:1 metal to ligand stoichiometry. Trigonal bipyramidal geometry has been assigned for Ni(II) and Cu(II) complexes, while tetrahedral for Co(II) and Zn(II) complexes. The compounds were subjected to antimicrobial and anti-tubercular activity screening using serial broth dilution method and Minimum Inhibitory Concentration (MIC) is determined. Zn(II) complex has shown significant antifungal activity with an MIC of 6.25 μg/mL while Cu(II) complex is noticeable for antibacterial activity at the same concentration. Anti-TB activity of the ligand has enhanced on complexation with Co(II) and Ni(II) ions.

  10. DNA cleavage, antimicrobial, spectroscopic and fluorescence studies of Co(II), Ni(II) and Cu(II) complexes with SNO donor coumarin Schiff bases

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

    A series of Co(II), Ni(II) and Cu(II) complexes of the type ML 2 have been synthesized with Schiff bases derived from methylthiosemicarbazone and 5-formyl-6-hydroxy coumarin/8-formyl-7-Hydroxy-4-methylcoumarin. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMF indicate that, the complexes are non-electrolytes in nature. In view of analytical, spectral (IR, UV-vis, ESR, FAB-mass and fluorescence), magnetic and thermal studies, it has been concluded that, all the metal complexes possess octahedral geometry in which ligand is coordinated to metal ion through azomethine nitrogen, thione sulphur and phenolic oxygen atom via deprotonation. The redox behavior of the metal complexes was investigated by using cyclic voltammetry. The Schiff bases and their complexes have been screened for their antibacterial ( Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities ( Aspergillus niger, Aspergillus flavus and Cladosporium) by Minimum Inhibitory Concentration method. The DNA cleavage is studied by agarose gel electrophoresis method.

  11. Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment.

    PubMed

    El-Baradie, K; El-Sharkawy, R; El-Ghamry, H; Sakai, K

    2014-01-01

    The azodye ligand (HL(1)) was synthesized from the coupling of sulfaguanidine diazonium salt with 2,4-dihydroxy-benzaldehyde while the two ligands, HL(2) and HL(3), were prepared by the coupling of sulfadiazine diazonium salt with salicylaldehyde (HL(2)) and 2,4-dihydroxy-benzaldehyde (HL(3)). The prepared ligands were characterized by elemental analysis, IR, (1)H 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 HL(1) and HL(3). HL(2) 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 HO 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.

  12. Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment

    NASA Astrophysics Data System (ADS)

    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.

  13. Changes in spectrochemical and catalytic properties of biopolymer anchored Cu(II) and Ni(II) catalysts by electron beam irradiation.

    PubMed

    Antony, R; Suja Pon Mini, P S; Theodore David Manickam, S; Sanjeev, Ganesh; Mitu, Liviu; Balakumar, S

    2015-01-01

    Chitosan (a biopolymer) anchored Cu(II) and Ni(II) Schiff base complexes, [M(OIAC)Cl2] (M: Cu/Ni and OIAC: ([2-oxo-1H-indol-3-ylidene]amino)chitosan) were electron beam irradiated by different doses (100 Gy, 1 kGy and 10 kGy). The electron beam has shown potential impact on biopolymer's support, in detail chain linking and chain scissoring, as evidenced by viscosity studies, FT-IR and X-ray diffraction spectroscopic techniques. Due to these structural changes, thermal properties of the complexes were found to be changed. The surface of these heterogeneous complexes was also effectually altered by electron beam. As a consequence, pores and holes were created as probed by SEM technique. The catalytic activity of both non-irradiated and irradiated complexes was investigated in the aerobic oxidation of cyclohexane using hydrogen peroxide oxidant. The catalytic ability of the complexes was enhanced significantly after irradiation as the result of surface changes. The reusability of the complexes was also greatly affected because of the structural variations in polymeric support. In terms of both better catalytic activity along with the reusability, 1 kGy is suggested as the best dose to attain adequate increase in catalytic activity and good reusability.

  14. Batch sorption dynamics, kinetics and equilibrium studies of Cr(VI), Ni(II) and Cu(II) from aqueous phase using agricultural residues

    NASA Astrophysics Data System (ADS)

    Kaur, Rajvinder; Singh, Joginder; Khare, Rajshree; Cameotra, Swaranjit Singh; Ali, Amjad

    2013-03-01

    In the present study, the agricultural residues viz., Syzygium cumini and Populus deltoides leaves powder have been used for the biosorption of Cu(II), Ni(II), and Cr(VI) from aqueous solutions. FTIR and SEM analysis of the biosorbents were performed to explore the type of functional groups available for metal binding and to study the surface morphology. Various physico-chemical parameters such as pH, adsorbent dosage, initial metal ion concentration, and equilibrium contact time were studied. Thermodynamic studies were carried out and the results demonstrated the spontaneous and endothermic nature of the biosorption process. The equilibrium data were tested using four isotherm models—Langmuir, Freundlich, Temkin and Dubinin-Radushkevich and the maximum biosorption capacities were evaluated. The Pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models were applied to study the reaction kinetics with pseudo-second order model giving the best fit ( R 2 = 0.99) to the experimental data.

  15. Synthesis, physico-chemical investigations of Co(II), Ni(II) and Cu(II) complexes and their in vitro microbial, cytotoxic, DNA cleavage studies.

    PubMed

    Bagihalli, Gangadhar B; Patil, Sangamesh A

    2010-06-01

    A series of metal complexes of cobalt(II), nickel(II), and copper(II) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 2-amino-4-phenyl-1,3-thiazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The probable structure of the complexes has been proposed on the basis of analytical and spectroscopic data (IR, UV-Vis, ESR, FAB-mass, and thermoanalytical). Electrochemical study of the complexes is also reported. Elemental analysis of the complexes confined them to stoichiometry of the type ML(2).2H(2)O [M = Co(II), Ni(II), and Cu(II)]. The Schiff base and its metal(II) complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes, and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the MIC method. The brine shrimp bioassay was carried out to study their in vitro cytotoxic properties, and also the Schiff base and its metal(II) complexes have been studied for DNA cleavage.

  16. Synthesis, characterization, DFT and biological studies of (Z)-N‧-(2-oxoindolin-3-ylidene)picolinohydrazide and its Co(II), Ni(II) and Cu(II) complexes

    NASA Astrophysics Data System (ADS)

    Rakha, T. H.; El-Gammal, O. A.; Metwally, H. M.; Abu El-Reash, G. M.

    2014-03-01

    The picolinohydrazide derivative: (Z)-N‧-(2-oxoindolin-3-ylidene)picolinohydrazide (H2IPH) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and investigated by using the modern spectroscopic and physicochemical techniques viz. IR, 1H NMR, UV-Vis spectrometric methods and magnetic moment measurements. The investigation study revealed that the ligand acts as monobasic tri- and tetradentate in Co(II) and Ni(II) complex, respectively and as neutral tridentate in Cu(II) complex. On the basis of magnetic moment and spectral studies, a six coordinated octahedral geometry is assigned for all complexes. The molecular modeling are drawn and showed the bond length, bond angle, chemical reactivity, energy components (kcal/mol) and binding energy (kcal/mol) for all the title compounds and also NLO for the ligand is shown. The energy gap between the HOMO and LUMO for Ni(II) complex is (-7 eV) which indicates that these compound is a promising structure for photovoltaic devices such as solar cells. A comparison of the experimental and theoretical spectra can be very useful in making correct assignments and understanding the basic chemical shift. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The in vitro antibacterial studies of these complexes screened against pathogenic bacteria proved them as growth inhibiting agents. Antitumor activity, carried out in vitro on human mammary gland (breast) MCF7, have shown that the Co(II) complex exhibited potent activity followed by the ligand, Cu(II) and Ni(II) complexes.

  17. Synthesis, characterization antibacterial and antiproliferative activity of novel Cu(II) and Pd(II) complexes with 2-hydroxy-8-R-tricyclo[7.3.1.0.(2,7)]tridecane-13-one thiosemicarbazone.

    PubMed

    Rosu, Tudor; Pahontu, Elena; Pasculescu, Simona; Georgescu, Rodica; Stanica, Nicolae; Curaj, Adelina; Popescu, Alexandra; Leabu, Mircea

    2010-04-01

    Synthesis and biological activity investigation of complex compounds of Cu(II) are challenging issues because of the metal is not a xenobiotic one and the activity of ligands could be modulated by complexation. Complex combinations of Cu(II) and Pd(II) with thiosemicarbazone derivatives of 2-hydroxy-8-R-tricyclo[7.3.1.0.(2,7)]tridecane-13-one (where R=C(3)H(7), C(4)H(3)O) were synthesized. The characterization of the ligands and the newly formed compounds was done by (1)H NMR, (13)C NMR, UV-vis, IR, ESR spectroscopy, elemental analysis, molar electric conductibility and thermal studies. Experiments performed to identify the structures proved that the ligands coordinate to metal ions in different ways - neutral bidentate or mononegative bidentate. Also, if copper(II) acetate, copper(II) nitrate, copper(II) chloride and copper(II) thiocyanate were used, the ligands coordinated in a mononegative bidentate fashion. If copper(II) sulfate was used, the ligands coordinated in a neutral bidentate fashion. The biological activity for the copper(II) synthesized compounds was assessed in terms of antibacterial or antiproliferative activity. The antibacterial activity of the complexes against Staphylococcus aureus var. Oxford 6538, Escherichia coli ATCC 10536, Klebsielle pneumoniae ATCC 100131 and Candida albicans ATCC 10231 strains was studied and compared with that of free ligands. The effect of complex compounds on the proliferation of HeLa cells was tested. For all tested complexes an antiproliferative activity was noted at concentrations higher than 1 microM, but lower than 10 microM. Therefore, complex compounds of copper(II) were synthesized, structurally characterized and tested for biological activity, proving both antibacterial and antiproliferative activity.

  18. Synthesis and Characterization of Novel Cu(II), Pd(II) and Pt(II) Complexes with 8-Ethyl-2-hydroxytricyclo(7.3.1.0(2,7))tridecan-13-one-thiosemicarbazone: Antimicrobial and in Vitro Antiproliferative Activity.

    PubMed

    Pahonțu, Elena; Paraschivescu, Codruța; Ilieș, Diana-Carolina; Poirier, Donald; Oprean, Camelia; Păunescu, Virgil; Gulea, Aurelian; Roșu, Tudor; Bratu, Ovidiu

    2016-05-21

    New Cu(II), Pd(II) and Pt(II) complexes, (Cu(L)(H₂O)₂(OAc)) (1), (Cu(HL)(H₂O)₂(SO₄)) (2), (Cu(L)(H₂O)₂(NO₃)) (3), (Cu(L)(H₂O)₂(ClO₄)) (4), (Cu(L)₂(H₂O)₂) (5), (Pd(L)(OAc))H₂O (6), and (Pt(L)₂) (7) were synthesized from 8-ethyl-2-hydroxytricyclo(7.3.1.0(2,7))tridecan-13-one thiosemicarbazone (HL). The ligand and its metal complexes were characterized by IR, ¹H-NMR, (13)C-NMR, UV-Vis, FAB, EPR, mass spectroscopy, elemental and thermal analysis, magnetic susceptibility measurements and molar electric conductivity. The free ligand and the metal complexes have been tested for their antimicrobial activity against E. coli, S. enteritidis, S. aureus, E. faecalis, C. albicans and cytotoxicity against the NCI-H1573 lung adenocarcinoma, SKBR-3 human breast, MCF-7 human breast, A375 human melanoma and HL-60 human promyelocytic leukemia cell lines. Copper complex 2 exhibited the best antiproliferative activities against MCF-7 human breast cancer cells. A significant inhibition of malignant HL-60 cell growth was observed for copper complex 2, palladium complex 6 and platinum complex 7, with IC50 values of 1.6 µM, 6.5 µM and 6.4 µM, respectively.

  19. Synthesis and studies on Cu(II), Co(II), Ni(II) complexes of Knoevenagel β-diketone ligands.

    PubMed

    Sumathi, S; Tharmaraj, P; Sheela, C D; Anitha, C

    2012-11-01

    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, (1)H NMR, Mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are non-electrolytic in nature. Spectroscopic and other analytical data of the complexes suggest octahedral geometry for other metal(II) complexes. The redox behavior 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 the bacteria Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus as well as the fungus Candida albicans by well diffusion method. The zone of inhibition value indicates that the most of 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 (L1-L3) was found to be considerable effect than that of urea and KDP (potassium dihydrogen phosphate).

  20. Synthesis, spectral characterization and microbiological studies of Co(II), Ni(II) and Cu(II) complexes with some novel 20-membered macrocyclic hydrazino-1,2,4-triazole Schiff bases.

    PubMed

    Avaji, Prakash Gouda; Patil, Sangamesh Amarappa

    2009-02-01

    A series of Co(II), Ni(II) and Cu(II) complexes have been synthesized by template condensation of 2,6-diformyl-4-methylphenol and 3-substituted-4-amino-5-hydrazino-1,2,4-triazole with CoCl(2).6H(2)O, NiCl(2).6H(2)O and CuCl(2).2H(2)O chlorides in 2 + 2+2 molar ratio in ethanol. These complexes were characterized by elemental analyses, magnetic susceptibility, molar conductance, spectral (IR, Uv-Vis, ESR, (1)H NMR and FAB-mass), thermal, fluorescence and solid-state DC electrical conductivity studies. The observed molar conductance values indicate that they are non-electrolytes. Elemental analyses suggest the complexes to have 2:1 stoichiometry of the type [M(2)LX(2)] 2H(2)O (M = Co(II) & Cu(II), L = L(I)-L(IV) and X = Cl) and [Ni(2)LX(2)2H(2)O] 2H(2)O. The solid state DC electrical conductivity showed that the complexes were semiconducting. All the Schiff bases and their Co(II), Ni(II) and Cu(II) complexes were evaluated for their microbiological properties and some compounds showed promising results.

  1. Characterization and electrochemical studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes with 2-mercapto-3-substituted-quinazolin-4-one and 1,10-phenanthroline or ethylenediamine as ligands

    NASA Astrophysics Data System (ADS)

    Sawant, V. A.; Gotpagar, S. N.; Yamgar, B. A.; Sawant, S. K.; Kankariya, R. D.; Chavan, S. S.

    2009-04-01

    Some mixed ligand complexes of the type [M(L 1 or L 2)( phen or en)(H 2O)Cl], where M = Mn(II), Co(II), Ni(II) and Cu(II); HL 1 = 2-mercapto-quinazolin-4-one; HL 2 = 2-mercapto-3-phenyl-quinazolin-4-one; phen = 1,10-phenanthroline; en = ethylenediamine have been prepared. All complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, IR, UV-vis, ESR and powder X-ray diffraction studies. IR spectra of these complexes reveal that the complex formation occurred through both nitrogen and sulphur atoms. On the basis of electronic spectral data and magnetic susceptibility measurement octahedral geometry has been proposed for the complexes. The ESR spectral data of the Cu(II) complexes showed that the metal-ligand bonds have considerable covalent character. X-ray diffraction studies of Cu(II) complexes are used to elucidate the crystal structure. The electrochemical behaviour of mixed ligand Ni(II) complexes was studied which showed that complexes of phen appear at more positive potential as compared to those for corresponding en complexes.

  2. Characterization and electrochemical studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes with 2-mercapto-3-substituted-quinazolin-4-one and 1,10-phenanthroline or ethylenediamine as ligands.

    PubMed

    Sawant, V A; Gotpagar, S N; Yamgar, B A; Sawant, S K; Kankariya, R D; Chavan, S S

    2009-04-01

    Some mixed ligand complexes of the type [M(L(1) or L(2))(phen or en)(H(2)O)Cl], where M=Mn(II), Co(II), Ni(II) and Cu(II); HL(1)=2-mercapto-quinazolin-4-one; HL(2)=2-mercapto-3-phenyl-quinazolin-4-one; phen=1,10-phenanthroline; en=ethylenediamine have been prepared. All complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, IR, UV-vis, ESR and powder X-ray diffraction studies. IR spectra of these complexes reveal that the complex formation occurred through both nitrogen and sulphur atoms. On the basis of electronic spectral data and magnetic susceptibility measurement octahedral geometry has been proposed for the complexes. The ESR spectral data of the Cu(II) complexes showed that the metal-ligand bonds have considerable covalent character. X-ray diffraction studies of Cu(II) complexes are used to elucidate the crystal structure. The electrochemical behaviour of mixed ligand Ni(II) complexes was studied which showed that complexes of phen appear at more positive potential as compared to those for corresponding en complexes.

  3. Spectroscopic and structural study of some 2,5-hexanedione bis(salicyloylhydrazone) complexes: Crystal structures of its Ni(II) and Cu(II) complexes and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxy-benzamide

    NASA Astrophysics Data System (ADS)

    Jeragh, Bakir; El-Asmy, Ahmed A.

    2014-08-01

    The reaction between 2,5-hexanedione and salicylic acid hydrazide produced two compounds: 2,5-hexanedione bis(salicyloylhydrazone) [HDSH] (ethanol insoluble) and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide [DPH] (ethanol soluble). HDSH formed complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and Pd(II) which are characterized by elemental analyses, spectra (IR, 1H NMR, ESR and MS), thermal and magnetic measurements. The crystals of [Ni(HDSH-2H)(EtOH)(H2O)] and [Cu(HDSH-2H)] were solved having octahedral and square-planar geometries, respectively. The other complexes have the formulae [Co(HDSH-2H)(H2O)2], [Cu(HDSH-H)2], [Zn(HDSH-2H)(H2O)2], [Cd2(HDSH-4H)(H2O)4], [Cd2(HDSH-2H)(H2O)4Cl2]; [Hg(HDSH-2H)] and [Pd2(HDSH-4H)(H2O)4]. The obtained complexes are stable in air and non-hygroscopic. The magnetic moments and electronic spectra of the complexes provide different geometries. The ESR spectra support the mononuclear geometry for [Cu(HDSH-2H)] and [Cu(HDSH-H)2]. The thermal decomposition of the complexes revealed the coordinated waters as well as the end product which is in most cases the metal oxide. The crystal structure of N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide is solved by X-ray technique.

  4. Spectroscopic and structural study of some 2,5-hexanedione bis(salicyloylhydrazone) complexes: crystal structures of its Ni(II) and Cu(II) complexes and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxy-benzamide.

    PubMed

    Jeragh, Bakir; El-Asmy, Ahmed A

    2014-08-14

    The reaction between 2,5-hexanedione and salicylic acid hydrazide produced two compounds: 2,5-hexanedione bis(salicyloylhydrazone) [HDSH] (ethanol insoluble) and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide [DPH] (ethanol soluble). HDSH formed complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and Pd(II) which are characterized by elemental analyses, spectra (IR, (1)H NMR, ESR and MS), thermal and magnetic measurements. The crystals of [Ni(HDSH-2H)(EtOH)(H2O)] and [Cu(HDSH-2H)] were solved having octahedral and square-planar geometries, respectively. The other complexes have the formulae [Co(HDSH-2H)(H2O)2], [Cu(HDSH-H)2], [Zn(HDSH-2H)(H2O)2], [Cd2(HDSH-4H)(H2O)4], [Cd2(HDSH-2H)(H2O)4Cl2]; [Hg(HDSH-2H)] and [Pd2(HDSH-4H)(H2O)4]. The obtained complexes are stable in air and non-hygroscopic. The magnetic moments and electronic spectra of the complexes provide different geometries. The ESR spectra support the mononuclear geometry for [Cu(HDSH-2H)] and [Cu(HDSH-H)2]. The thermal decomposition of the complexes revealed the coordinated waters as well as the end product which is in most cases the metal oxide. The crystal structure of N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide is solved by X-ray technique.

  5. Hydrothermal Syntheses and Crystal Structures of Ni(II), Co(II), and Cu(II), Bis( trans-4-pyridylacrylate) Interpenetration Networks

    NASA Astrophysics Data System (ADS)

    Liu, Yen-Hsiang; Lin, Chia-Shiang; Chen, Shiang-Ying; Tsai, Hui-Lien; Ueng, Chuen-Her; Lu, Kuang-Lieh

    2001-02-01

    Three metal-organic polymeric networks, Ni(C8H6NO2)2(H2O)2 (1), Co(C8H6NO2)2 (2), and Cu(C8H6NO2)2(H2O)2 (3), were synthesized by the hydrothermal method. Single-crystal X-ray analysis revealed that within these compounds metal centers are linked through trans-4-pyridylacrylate ligands to form interpenetrating infinite networks. The Ni(II) and Cu(II) compounds possess an overlay of interpenetrating square grid layers, whereas the Co(II) compound possesses interpenetrating diamondoid networks. Comparing these three compounds, the formation of cavities potentially for guest molecule inclusion within the interpenetrating networks could be achieved by taking advantage of the coordination nature of metals. Crystal structures of all three compounds were determined by single-crystal X-ray diffraction methods and solved by direct method. Crystal data for 1: orthorhombic, space group Pbcn, a=13.735(3) Å, b=6.995(2) Å, c=16.723(3) Å, V=1606.7(6) Å3, Z=4, final refinement (I>2σ(I)): R1=0.0296, wR2=0.0843. Crystal data for 2: monoclinic, space group Cc, a=11.5717(9) Å, b=21.2838(16) Å, c=8.5504(7) Å, β=130.5210(10)°, V=1600.8(2) Å3, Z=4, final refinement (I>2σ(I)): R1=0.0347, wR2=0.0879. Crystal data for 3: orthorhombic, space group Pbcn, a=13.6844(13) Å, b=7.5053(8) Å, c=15.929(4) Å, V=1636.0(5) Å3, Z=4, final refinement (I>2σ(I)), R1=0.0299, wR2=0.0787.

  6. Immobilization of heavy metal ions (CuII, CdII, NiII, and PbII) by broiler litter-derived biochars in water and soil.

    PubMed

    Uchimiya, Minori; Lima, Isabel M; Thomas Klasson, K; Chang, SeChin; Wartelle, Lynda H; Rodgers, James E

    2010-05-12

    Chars, a form of environmental black carbon resulting from incomplete burning of biomass, can immobilize organic contaminants by both surface adsorption and partitioning mechanisms. The predominance of each sorption mechanism depends upon the proportion of organic to carbonized fractions comprising the sorbent. Information is currently lacking in the effectiveness of char amendment for heavy metal immobilization in contaminated (e.g., urban and arms range) soils where several metal contaminants coexist. The present study employed sorbents of a common biomass origin (broiler litter manure) that underwent various degrees of carbonization (chars formed by pyrolysis at 350 and 700 degrees C and steam-activated analogues) for heavy metal (Cd(II), Cu(II), Ni(II), and Pb(II)) immobilization in water and soil. ATR-FTIR, (1)H NMR, and Boehm titration results suggested that higher pyrolysis temperature and activation lead to the disappearance (e.g., aliphatic -CH(2) and -CH(3)) and the formation (e.g., C-O) of certain surface functional groups, portions of which are leachable. Both in water and in soil, pH increase by the addition of basic char enhanced the immobilization of heavy metals. Heavy metal immobilization resulted in nonstoichiometric release of protons, that is, several orders of magnitude greater total metal concentration immobilized than protons released. The results suggest that with higher carbonized fractions and loading of chars, heavy metal immobilization by cation exchange becomes increasingly outweighed by other controlling factors such as the coordination by pi electrons (C=C) of carbon and precipitation.

  7. Synthesis, spectral, thermal and magnetic studies of Mn(II), Ni(II) and Cu(II) complexes with some benzopyran-4-one Schiff bases.

    PubMed

    el-Ansary, Aida L; Abdel-Fattah, Hussein M; Abdel-Kader, Nora S

    2011-08-01

    The Schiff bases of N(2)O(2) dibasic ligands, H(2)La and H(2)Lb are prepared by the condensation of ethylenediamine (a) and trimethylenediamine (b) with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzopyran-4-one. Also tetra basic ligands, H(4)La and H(4)Lb are prepared by the condensation of aliphatic amines (a) and (b) with 6-formyl-5,7-dihydroxy-2-methylbenzopyran-4-one. New complexes of H(4)La and H(4)Lb with metal ions Mn(II), Ni(II) and Cu(II) are synthesized, in addition Mn(II) complexes with ligands H(2)La and H(2)Lb are also synthesized. Elemental and thermal analyses, infrared, ultraviolet-visible as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure of the newly prepared metal complexes. The structures of copper(II) complexes are also assigned based upon ESR spectra study. All the complexes separated with the stoichiometric ratio (1:1) (M:L) except Mn-H(4)La and Mn-H(4)Lb with (2:1) (M:L) molar ratio. In metal chelates of the type 1:1 (M:L), the Schiff bases behave as a dinegative N(2)O(2) tetradentate ligands. Moreover in 2:1 (M:L) complexes, the Schiff base molecules act as mono negative bidentate ligand and binuclear complex is then formed. The Schiff bases were assayed by the disc diffusion method for antibacterial activity against Staphylococcus aureus and Escherichia coli. The antifungal activity of the Schiff bases was also evaluated against the fungi Aspergillus flavus and Candida albicans.

  8. Cu(II), Ni(II) and Co(II) co-ordination properties and tautomerism of 1,8-bis-phenylazo-2,7-dihydroxy naphthalene. A spectroscopic and semiempirical AM1/PM3 study

    NASA Astrophysics Data System (ADS)

    Arancibia, J. A.; Olivieri, A. C.; Escandar, G. M.

    2000-04-01

    As a continuation of a study on the prototropic properties of aromatic α,α'-dihydroxy-bis-azocompounds, 1,8-bis-phenylazo-2,7-dihydroxynaphthalene (PHADN) has been studied through 1H and 13C nuclear magnetic resonance experiments, electronic absorption and semiempirical molecular orbital methods. In addition, the metal binding properties of this compound were evaluated and related with its tautomeric forms. The equilibrium constants for Cu(II), Ni(II) and Co(II)-PHADN complexes were spectrophotometrically determined in dioxane-water 50% v/v solutions. The structures of the evaluated chelates were proposed on the basis of spectral analysis and PM3 semiempirical calculations.

  9. A new chelating resin for preconcentration and determination of Mn(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) by flame atomic absorption spectrometry.

    PubMed

    Maheswari, Mohan A; Subramanian, Mandakolathur S

    2003-01-01

    A new polychelatogen, AXAD-16-1,2-diphenylethanolamine, was developed by chemically modifying Amberlite XAD-16 with 1,2-diphenylethanolamine to produce an effective metal-chelating functionality for the preconcentration of Mn(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) and their determination by flame atomic absorption spectrometry. Various physiochemical parameters that influence the quantitative preconcentration and recovery of metal were optimized by both static and dynamic techniques. The resin showed superior extraction efficiency with high-metal loading capacity values of 0.73, 0.80, 0.77, 0.87, 0.74, and 0.81 mmol/g for Mn(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II), respectively. The system also showed rapid metal-ion extraction and stripping, with complete saturation in the sorbent phase within 15 min for all the metal ions. The optimum condition for effective metal-ion extraction was found to be a neutral pH, which is a great advantage in the preconcentration of trace metal ions from natural water samples without any chemical pretreatment of the sample. The resin also demonstrated exclusive ion selectivity toward targeted metal ions by showing greater resistivity to various complexing species and more common metal ions during analyte concentration, which ultimately led to high preconcentration factors of 700 for Cu(II); 600 for Mn(II), Ni(II), and Zn(II); and 500 for Cd(II) and Pb(II), arising from a larger sample breakthrough volume. The lower limits of metal-ion detection were 7 ng/mL for Mn(II) and Ni(II); 5 ng/mL for Cu(II), Zn(II), and Cd(II), and 10 ng/mL for Pb(II). The developed resin was successful in preconcentrating metal ions from synthetic and real water samples, multivitamin-multimineral tablets, and curry leaves (Murraya koenigii) with relative standard deviations of < or = 3.0% for all analytical measurements, which demonstrated its practical utility.

  10. Synthesis, spectral and thermal studies of Co(II), Ni(II) and Cu(II) complexes 1-(4,6-dimethyl-pyrimidin-2-ylazo)-naphthalen-2-ol.

    PubMed

    Gaber, M; Ayad, M M; El-Sayed, Y S Y

    2005-11-01

    The electronic absorption spectra of 1-(4,6-dimethyl-pyrimidin-2-ylazo)-naphthalen-2-ol is studied in organic solvents of different polarity as well as in buffer solutions of varying pH values at different temperatures and different ratios of methanol. The probable structure of the azodye has been assigned on the basis of spectral studies (IR and (1)H NMR). The effect of Co(II), Ni(II) and Cu(II) ions on the emission spectrum of the free azodye is also assigned. The stoichiometry of the metal complexes is determined spectrophotometrically and conductometrically. Novel complexes of Co(II), Ni(II) and Cu(II) with the pyrimidine azodye have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic as well as ESR spectral studies The thermal decomposition of the metal complexes is studied by TGA and DTA techniques. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation are estimated.

  11. Synthesis, spectroscopic characterization, molecular modeling and potentiometric studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 1,1-diaminobutane-Schiff base

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.

    2014-08-01

    Complexes of cobalt(II), nickel(II), copper(II) and zinc(II) of general composition [M(L)(H2O)2]·2H2O have been synthesized [L = N,N";-bis(2-hydroxybenzylidene)-1,1-diaminobutane]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR, SEM, EDX, thermal and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a tetradentate manner. The molar conductance of the complexes in fresh solution of DMSO lies in the range of 7.46-9.13 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The Schiff base acts as tetradentate ligand, coordinated through deprotonated phenolic oxygen and azomethine nitrogen atoms. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The molecular parameters of the ligand and its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been calculated. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M sodium perchlorate.

  12. Synthesis, characterization and biological activity of some new VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based NNO Schiff base derived from 2-aminothiazole

    NASA Astrophysics Data System (ADS)

    Kalanithi, M.; Kodimunthiri, D.; Rajarajan, M.; Tharmaraj, P.

    2011-11-01

    Coordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base obtained through the condensation of 2-aminothiazole with 3-formyl chromone were synthesized. The compounds were characterized by 1H, 13C NMR, UV-Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. The Cu(II) complex possesses tetrahedrally distorted square planar geometry whereas Co(II), Ni(II), and Zn(II) show distorted tetrahedral geometry. The VO(IV) complex shows square pyramidal geometry. The cyclic voltammogram of Cu (II) complex showed a well defined redox couple Cu(II)/Cu(I) with quasireversible nature. The antimicrobial activity against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger was screened and compared to the activity of the ligand. Emission spectrum was recorded for the ligand and the metal(II) complexes. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea. The SEM image of the copper(II) complex implies that the size of the particles is 2 μm.

  13. 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

    NASA Astrophysics Data System (ADS)

    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.

  14. Bonding analyses, formation energies, and vibrational properties of M-R2dtc complexes (M=Ag(I), Ni(II), Cu(II), or Zn(II)).

    PubMed

    Georgieva, I; Trendafilova, N

    2007-12-20

    Detailed theoretical studies based on density functional theory (DFT)/B3LYP calculations of dimethyl- and diethyldithiocarbamate complexes of Ni(II), Cu(II), Zn(II), and Ag(I) are performed to characterize the metal-ligand bonding type as well as the metal-ligand bonding strength depending on the metal and the dialkyl substituent. The metal-ligand interactions in the studied complexes are investigated by means of charge decomposition analysis, energy partitioning analysis (EPA), and natural bond orbital analysis. According to the EPA calculations, the electrostatic attraction is the dominant contribution to the M-S2(R2dtc) (dtc=dithiocarbamate) bonding. The electrostatic and the orbital energies follow the order of the total binding energy, and hence both contributions are responsible for the binding energy order of M(R2dtc)2 complexes. The stability of the M(R2dtc)2 complexes is estimated by means of calculated formation reaction energies in the gas phase and solution, and it decreases in the order Ni(R2dtc)2>Cu(R2dtc)2>Zn(R2dtc)2. Larger formation reaction energies are found for M(Et2dtc)2 than for M(Me2dtc)2 complexes. The calculations predict stabilization of M(II)(R2dtc)2 complexes going from the gas phase to a polar solvent and destabilization of the bidentate AgR2dtc complex in a polar solvent. Gas-phase frequency calculations of all possible bonding types, symmetrical, asymmetrical, and uni- and bidentate, predict one band due to the nu(CS) IR absorption, and therefore the number of the bands in the 1060-920 cm(-1) region could not be used to discern the metal-ligand bonding type. Periodic DFT frequency calculations for Cu(Et2dtc)2 reveal that the splitting observed in the solid-state spectra of the complexes arises from the nonplanar MS4 fragment and intermolecular contacts but not from asymmetrical bonding. The calculations suggest that the important vibrational characteristic that can be used to discern uni- and bidentate bonding is the Raman activity of

  15. Interaction of Co(II), Ni(II) and Cu(II) with dibenzo-substituted macrocyclic ligands incorporating both symmetrically and unsymmetrically arranged N, O and S donors.

    PubMed

    Vasilescu, I M; Baldwin, D S; Bourne, D J; Clegg, J K; Li, F; Lindoy, L F; Meehan, G V

    2011-09-14

    The synthesis and characterisation of four 17-membered, dibenzo-substituted macrocyclic ligands incorporating unsymmetrical arrangements of their N(3)S(2), N(3)O(2) and N(3)OS (two ligands) donor atoms are described; these rings complete the matrix of related macrocyclic systems incorporating both symmetric and unsymmetric donor sets reported previously. The X-ray structures of three of the new macrocycles are reported. In two of the Cu(II) structures only three of the possible five donor atoms present in the corresponding macrocyclic ligand bind to the Cu(II) site, whereas all five donors are coordinated in each of the remaining complexes. The interaction of Co(II), Ni(II) and Cu(II) with the unsymmetric macrocycle series has been investigated by potentiometric (pH) titration in 95% methanol; X-ray structures of two nickel and three copper complexes of these ligands, each exhibiting 1:1 (M:L) ratios, have been obtained. The results are discussed in the context of previous results for these metals with the analogous 17-membered ring systems incorporating symmetrical arrangements of their donor atoms, with emphasis being given to both the influence of the donor atom set, as well as the donor atom sequence, on the nature of the resulting complexes.

  16. Spectroscopic and thermal degradation behavior of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes with thiopental sodium anesthesia drug

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.

    2013-04-01

    A new series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized with thiopental sodium anesthesia drug. The elemental analyses of the complexes are confined to stoichiometry of the formulas [M(TPL)3]ṡnH2O (M = Cr(III) or Fe(III); n = 6 or 5), [M(TPL)2(H2O)2]ṡnH2O (M = Mn(II), Co(II) or Ni(II); n = 0 or 4), and [M(TPL)2] (M = Cu(II) or Zn(II); n = 2 or 0) respectively, where TPL is thiopental chelating agent. Structures have been discussed and suggested upon elemental analyses, infrared, Raman, electronic, electron spin resonance, 1H NMR spectral data and magnetic studies. The X-ray powder diffraction (XRD) was performed of metal complexes. The XRD patterns indicate crystalline nature for the complexes. The measured low molar conductance values in dimethylsulfoxide indicate that the complexes are non-electrolyte nature. Spectroscopic discussion refer that coordination take place through three types: Cdbnd N (pyrimidine moiety) nitrogen and C2sbnd S (2-thiolate group) for Cr(III), Mn(II) and Fe(III), C6dbnd O (amido group) oxygen and C2sbnd S (2-thiolate group) for Co(II) and Ni(II), and Cu(II) and Zn(II) ions coordinated via Cdbnd N (pyrimidine moiety) nitrogen, C2dbnd S (2-thiolate group) and C6dbnd O (amido group) oxygen, respectively. The thermal behavior (TG/DTG/DTA) of the complexes was studied and kinetic parameters were determined by Horowitz-Metzger and Coats-Redfern methods. The thiopental and its complexes have been screened for their antimicrobial (G+ and G-) bacteria (Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa) and fungi (Aspergillus flavus and Candida albicans) activities by minimum inhibitory concentration (MIC) method.

  17. Synthesis, structural characterization, thermal and electrochemical studies of the N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine and its Cu(II), Co(II) and Ni(II) metal complexes.

    PubMed

    Dolaz, Mustafa; McKee, Vickie; Gölcü, Ayşegül; Tümer, Mehmet

    2009-01-01

    In this study, N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine (L) and its Cu(II), Co(II) and Ni(II) complexes were prepared and characterized by the analytical and spectroscopic methods. The analytical data show the composition of the metal complex to be [M(2)L(Cl)(4)(H(2)O)(2)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. The compound (L) behaves as a monodentate ligand. But, obtained complexes have binuclear nature. The electrochemical properties of the metal complexes are dependent on reversible, irreversible and quasi-reversible redox waves in the anodic and cathodic regions due to oxidation and reduction of the metal ions. The single crystal of the ligand (L) was obtained from CH(3)CN solution. Space group and crystal system of the ligand are P2(1)/C and monoclinic, respectively.

  18. Synthesis, characterization and electrochemical study of synthesis of a new Schiff base (H₂cddi(t)butsalen) ligand and their two asymmetric Schiff base complexes of Ni(II) and Cu(II) with NN'OS coordination spheres.

    PubMed

    Menati, Saeid; Azadbakht, Azadeh; Taeb, Abbas; Kakanejadifard, Ali; Khavasi, Hamid Reza

    2012-11-01

    A novel Schiff base (H(2)cddi(t)butsalen) ligand was prepared via condensation of Methyl-2-{N-(2'-aminoethane)}-amino-1-cyclopentenedithiocarboxylate(Hcden) and 3,5-di-tert-butyl-2-hydroxybenzaldehyde. The ligand and Ni(II) and Cu(II) complexes were characterized based on elemental analysis, IR, (1)H NMR, (13)C NMR, UV-Vis spectrometry and cyclic voltammetry. The structure of copper{methyl-2-{N-[2-(3,5-di-tert-butyl-2-hydroxyphenyl)methylidynenitrilo]ethyl}amino-1-cyclopentedithiocarboxylate has been determined by X-ray crystallography. The X-ray results confirm that the geometry of the complex is slightly distorted square-planar structure. The copper(II) ion coordinates to two nitrogen atoms from the imine moiety of the ligand, a sulfur atom the methyl dithiocarboxylate moiety and phenolic oxygen atom.

  19. Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) new complexes of 5-aminosalicylic acid: Spectroscopic, thermal characterization and biological activity studies

    NASA Astrophysics Data System (ADS)

    Soliman, Madiha H.; Mohamed, Gehad G.

    2013-04-01

    The complexing behavior of mesalazine (5-aminosalicylic acid; 5-ASA) towards the transition metal ions namely, Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) have been examined by elemental analyses, magnetic measurements, electronic, IR and 1H NMR. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation, mathematical analyses and evaluation of kinetic parameters of all thermal decomposition stages have been evaluated using Coats-Redfern equation. The free ligand and its metal complexes have been tested in vitro against Aspergillus fumigatus and Candida albicans fungi and Pseudomonas aeruginosa, Escherichia coli, Bacillis subtilies and Staphylococcus aureus bacteria in order to assess their antimicrobial potential. The results indicate that the metal complexes are also found to have more antimicrobial activity than the parent 5-ASA drug.

  20. Potentiometric and spectrophotometric study of a new dipodal ligand N, N'-bis{2-[(2-hydroxybenzylidine)amino]ethyl}malonamide with Co(II), Ni(II), Cu(II) and Zn(II)

    NASA Astrophysics Data System (ADS)

    Sahoo, Suban K.; Muthu, S. E.; Baral, Minati; Kanungo, B. K.

    2006-03-01

    A new dipodal ligand, N, N'-bis{2-[(2-hydroxybenzylidine)amino]ethyl}malonamide (BHAEM) was synthesized by Schiff base condensation of N, N'-bis(2-aminoethyl)malonamide with two equivalent of salicylaldehyde and characterized on the basis of elemental analyses and various spectral (UV-vis, IR, 1H NMR and 13C NMR) data. The complexation reaction of the ligand with H +, Co(II), Ni(II), Cu(II) and Zn(II) in solution was investigated by spectrophotometric and potentiometric method. Two protonation constants of BHAEM assigned for two hydroxyl groups of aromatic ring were determined and its hydrolysis mechanism was proposed through potentiometric result. In presence of metal ions, BHAEM shows different coordination properties. All metal ions form ML type complex where the ligand coordinates to the metal ion through two N-amine and two O-phenolate groups. In addition, Ni(II) and Cu(II) form additional complex species of the type MLH -1 and MLH -2, respectively due to ionization of amide protons. The molecular geometry of BHAEM was examined theoretically using the molecular mechanics MM3 force field followed by semi-empirical PM3 method and various spectral data UV-vis, IR and 1H NMR were calculated from the energy-minimized structure applying semi-empirical ZINDO, PM3 and TNDO/2 method, respectively and compared with the experimental data. The probable structure of metal complexes in solution were proposed through calculated minimum strain energy by applying molecular mechanics MM + force field coupled with molecular dynamics simulation. Further the proposed structure of Cu(BHAEM) was refined through semi-empirical AM1/d method.

  1. NiII, CuII and ZnII complexes with a sterically hindered scorpionate ligand (TpmsPh) and catalytic application in the diasteroselective nitroaldol (Henry) reaction.

    PubMed

    Rocha, Bruno G M; Mac Leod, Tatiana C O; Guedes da Silva, M Fátima C; Luzyanin, Konstantin V; Martins, Luísa M D R S; Pombeiro, Armando J L

    2014-10-28

    The Ni(II) and Zn(II) complexes [MCl(Tpms(Ph))] (Tpms(Ph) = SO3C(pz(Ph))3, pz = pyrazolyl; M = Ni 2 or Zn 3) and the Cu(II) complex [CuCl(Tpms(Ph))(H2O)] (4) have been prepared by treatment of the lithium salt of the sterically demanding and coordination flexible tris(3-phenyl-1-pyrazolyl)methanesulfonate (Tpms(Ph))(-) (1) with the respective metal chlorides. The (Tpms(Ph))(-) ligand shows the N3 or N2O coordination modes in 2 and 3 or in 4, respectively. Upon reaction of 2 and 3 with Ag(CF3SO3) in acetonitrile the complexes [M(Tpms(Ph))(MeCN)](CF3SO3) (M = Ni 5 or Zn 6, respectively) were formed. The compounds were obtained in good yields and characterized by analytic and spectral (IR, (1)H and (13)C{(1)H} NMR, ESI-MS) data, density functional theory (DFT) methods and {for 4 and [(n)Bu4N](Tpms(Ph)) (7), the latter obtained upon Li(+) replacement by [(n)Bu4N](+) in Li(Tpms(Ph))} by single crystal X-ray diffraction analysis. The Zn(II) and Cu(II) complexes (3 and 4, respectively) act as efficient catalyst precursors for the diastereoselective nitroaldol reaction of benzaldehydes and nitroethane to the corresponding β-nitroalkanols (up to 99% yield, at room temperature) with diastereoselectivity towards the formation of the anti isomer, whereas the Ni(II) complex 2 only shows a modest catalytic activity.

  2. Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate ONO donor Schiff base ligand: Synthesis, characterization, thermal, non-isothermal kinetics and DFT calculations

    NASA Astrophysics Data System (ADS)

    Kusmariya, Brajendra S.; Mishra, A. P.

    2017-02-01

    We report here four mononuclear Co(II), Ni(II), Cu(II) and Zn(II) coordination compounds of general formula [M(L)2] {L = dcp; M = CoII, CuII & ZnII} and [M(L)(H2O)]·H2O {L = dcp; M = NiII} derived from tridentate 2,4-dichloro-6-{[(3-chloro-2-hydroxy-5-nitrophenyl)imino]methyl}phenol (dcp) ligand. These compounds were synthesized and characterized by elemental analysis, FT-IR, uv-vis, 1H NMR, molar conductance, magnetic moment, thermal, PXRD and SEM-EDX. The Powder X-ray Diffraction patterns and SEM analyses showed the crystalline nature of synthesized compounds. The peak broadening was explained in terms of crystallite size and the lattice strain using Scherrer and Williamson-Hall method. Thermogravimetric analysis was performed to determine the thermal stability of synthesized compounds under nitrogen atmosphere up to 820 K at 10 Kmin-1 heating rate. The kinetic and thermodynamic parameters of thermal decomposition were calculated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods assuming first order degradation. The calculated optical band gap values of complexes were found to be in semiconducting range. To support the experimental findings, and derive some fruitful information viz. frequency calculations, HOMO-LUMO, energy gap (ΔE), molecular electrostatic potential (MEP), spin density, absorption spectra etc.; theoretical calculations by means of DFT and TD-DFT at B3LYP level were incorporated.

  3. Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO 2(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine

    NASA Astrophysics Data System (ADS)

    Sharaby, Carmen M.

    2005-11-01

    Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H 4L, l,3-[ N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO 2(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, 1H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4 keV γ-ray from radioactive 57Co (Mössbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H 4L ligand forms complexes of the general formulae [(MX z) 2(H 2L)H 2O) n] and [(FeSO 4) 2 (H 4L) (H 2O) 4], where X = NO 3 in case of UO 2(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.

  4. Synthesis, DNA-binding, DNA-photonuclease profiling and antimicrobial activity of novel tetra-aza macrocyclic Ni(II), Co(II) and Cu(II) complexes constrained by thiadiazole

    NASA Astrophysics Data System (ADS)

    Vinay Kumar, B.; Bhojya Naik, H. S.; Girija, D.; Sharath, N.; Pradeepa, S. M.; Joy Hoskeri, H.; Prabhakara, M. C.

    A new tetra-aza macrocyclic ligand, L (C24H16N12O2S4) and its complexes of type, [MLCl2] and [CuL]Cl2 (where M = Ni(II), Co(II); L = N,N'-(benzene-1,3-diyldi-1,3,4-thiadiazole-5,2-diyl)bis{2-[(5-benzene-1,3-diyl-1,3,4-thiadiazol-2-yl)amino]acetamide}) were synthesized and characterized by the spectral and analytical techniques. An octahedral geometry has been proposed for Ni(II) and Co(II) complexes while Cu(II) complex exhibit a square planar geometry. All the synthesized metal complexes were screened for their in vitro antimicrobial activity against selected species of pathogenic bacteria and fungi. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. The photo induced cleavage studies revealed that the complexes possess photonuclease property against pUC19 DNA under UV-visible irradiation.

  5. 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

    NASA Astrophysics Data System (ADS)

    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).

  6. Spectrophotometric, conductometric and thermal studies of Co(II), Ni(II) and Cu(II) complexes with 2-(2-hydroxynaphthylazo)-4-hydroxy-6-methyl-1,3-pyrimidine

    NASA Astrophysics Data System (ADS)

    Gaber, Mohamed; Mansour, Ikhlas A.; El-Sayed, Yousif S. Y.

    2007-10-01

    The electronic absorption spectra of 2-(2-hydroxynaphthylazo)-4-hydroxy-6-methyl-1,3-pyrimidine in pure organic solvents of different polarities and in buffer solutions of varying pH are studied. The important bands in the IR and the main signals in the 1H NMR spectra are assigned. The observed UV-vis absorption bands are assigned to the corresponding electronic transitions. The molecular stoichiometry, stability constant, absorption maximum, molar absorptivity and Sandell's sensitivity of the complexes are calculated. Obeyence to Beer's law and Ringbom optimum concentration ranges are also determined. The ability of using the titled azodye as metalochromic indicator in complexometric titrations was also studied. The effect of Co(II), Ni(II) and Cu(II) ions on the fluorescence of the azodye is also considered. The solid Cu(II) complexes of the titled azodye have been prepared and characterized by elemental, IR, UV-vis spectra as well as by conductometric and magnetic measurements. The data suggest square planar geometry for 1:1 and 1:2 (M:L) complexes. The thermal behaviour of the complexes has been studied. The kinetic parameters ( n, E, A, Δ H, Δ S and Δ G) of the thermal decomposition steps are computed using Coats-Redfern equations.

  7. 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

    NASA Astrophysics Data System (ADS)

    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.

  8. Proton/metal-ligand stability constants of complexes of Ni(II), Cu(II), and Co(II) with diethyl 4-(substituted-phenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate in 70% dioxane-water mixture

    NASA Astrophysics Data System (ADS)

    Tekade, Pradip V.; Bajaj, Sonal D.; Thool, Seemita

    2015-12-01

    Physico-chemical properties viz proton-ligand and metal-ligand stability constants of complexes of diethyl 4-(substituted-phenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate with Ni(II), Cu(II), and Co(II) were determined in mixed solvents (70% dioxane). Presence of OH/NH group(s) in these compounds was confirmed at 0.1 M ionic strength in 70% dioxane-water mixture pH-metrically. It is observed that Ni(II), Cu(II), and Co(II) metal ions formed 1: 1 and 1: 2 complex with all the three ligands. The results show that the ratio of log K 1/log K 2 is positive in all cases. This implies that there is little or no steric hindrance to the addition of secondary molecules.

  9. Synthesis and characterization of binary and ternary complexes of Co(II), Ni(II), Cu(II) and Zn(II) ions based on 4-aminotoluene-3-sulfonic acid

    NASA Astrophysics Data System (ADS)

    Faheim, Abeer A.; Abdou, Safaa N.; Abd El-Wahab, Zeinab H.

    2013-03-01

    Salicylidene (4-aminotoluene-3-sulfonic acid) Schiff base ligand H2L, and its binary and ternary Co(II), Ni(II), Cu(II) and Zn(II) complexes using 8-hydroxyquinoline (8-HOqu) and 2-aminopyridine (2-Ampy) as secondary ligands have been synthesised and characterized via elemental analysis, spectral data (IR, 1H NMR, mass and solid reflectance), molar conductance, magnetic moment, TG-DSC measurements and XRPD analysis. Correlation of all spectroscopic data suggest that H2L ligand acts as monoanionic terdentate ligand with ONO sites coordinating to the metal ions via deprotonated phenolic-O, azomethine-N and sulfonate-O while 2-Ampy behaves as a neutral monodentate ligand via amino group-N and 8-HOqu behaves as a monoanionic bidentate ligand through the ring-N and deprotonated phenolic-O. The thermal behavior of these complexes shows that the coordinated water molecules were eliminated from the complexes at relatively higher temperatures than the hydrated water and there are two routes in removal of coordinated water molecules. All complexes have mononuclear structure and the tetrahedral, square planar or an octahedral geometry have been proposed. The ligand and its complexes have been screened for their antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Candida albicans and Aspergillus fumigatus. Among the synthesised compounds, the binary and ternary Ni(II) complexes, (2, 8 and 10) and ternary Zn(II) complex, (12) were found to be very effective against Candida albicans and Bacillus subtilis than all other complexes with MICs of 2 and 8 μg/mL, respectively.

  10. Synthesis and characterization of binary and ternary complexes of Co(II), Ni(II), Cu(II) and Zn(II) ions based on 4-aminotoluene-3-sulfonic acid.

    PubMed

    Faheim, Abeer A; Abdou, Safaa N; Abd El-Wahab, Zeinab H

    2013-03-15

    Salicylidene (4-aminotoluene-3-sulfonic acid) Schiff base ligand H(2)L, and its binary and ternary Co(II), Ni(II), Cu(II) and Zn(II) complexes using 8-hydroxyquinoline (8-HOqu) and 2-aminopyridine (2-Ampy) as secondary ligands have been synthesised and characterized via elemental analysis, spectral data (IR, (1)H NMR, mass and solid reflectance), molar conductance, magnetic moment, TG-DSC measurements and XRPD analysis. Correlation of all spectroscopic data suggest that H(2)L ligand acts as monoanionic terdentate ligand with ONO sites coordinating to the metal ions via deprotonated phenolic-O, azomethine-N and sulfonate-O while 2-Ampy behaves as a neutral monodentate ligand via amino group-N and 8-HOqu behaves as a monoanionic bidentate ligand through the ring-N and deprotonated phenolic-O. The thermal behavior of these complexes shows that the coordinated water molecules were eliminated from the complexes at relatively higher temperatures than the hydrated water and there are two routes in removal of coordinated water molecules. All complexes have mononuclear structure and the tetrahedral, square planar or an octahedral geometry have been proposed. The ligand and its complexes have been screened for their antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Candida albicans and Aspergillus fumigatus. Among the synthesised compounds, the binary and ternary Ni(II) complexes, (2, 8 and 10) and ternary Zn(II) complex, (12) were found to be very effective against Candida albicans and Bacillus subtilis than all other complexes with MICs of 2 and 8 μg/mL, respectively.

  11. Self-assembled Cu(II) and Ni(II) metallamacrocycles formed from 3,3,3',3'-tetrabenzyl-1,1'-aroylbis(thiourea) ligands: DNA and protein binding studies, and cytotoxicity of trinuclear complexes.

    PubMed

    Selvakumaran, Nagamani; Bhuvanesh, Nattamai S P; Karvembu, Ramasamy

    2014-11-21

    Self-assembled metallamacrocyclic Cu(II) and Ni(II) complexes of the types [Cu(L1-O,S)]3 (1), [Ni(L1-O,S)]3 (2), [Cu(L2-O,S)]2 (3) and [Ni(L2-O,S)]2 (4) [H2L1 = 3,3,3',3'-tetrabenzyl-1,1'-terephthaloylbis(thiourea) and H2L2 = 3,3,3',3'-tetrabenzyl-1,1'-isophthaloylbis(thiourea)] were synthesized and characterized by analytical, spectroscopic (UV-Vis, FT-IR, mass, (1)H & (13)C NMR and EPR) and single crystal X-ray diffraction techniques. The crystal structures of [Ni(L1-O,S)]3 and [Cu(L2-O,S)(Py)]2 showed the formation of self-assembled 3:3 and 2:2 metallamacrocyclic Cu(II) and Ni(II) complexes respectively. The binding affinity and binding mode of the trinuclear complexes toward CT DNA were determined by UV-Vis spectrophotometric titrations and the fluorescent indicator displacement (FID) assay. The interaction of the ligand (H2L1) and the complexes (1 and 2) with BSA was investigated using UV-Vis and fluorescence spectroscopic methods. Absorption and emission spectral studies indicate that the complexes 1 and 2 interact with CT DNA and BSA protein more strongly than their parent ligand. Both the complexes (1 and 2) cleaved the pBR 322 plasmid DNA in the absence of an external agent. Complex 1 [IC50 = 22.36 (A549) and 10 μM (MCF7)] exhibited higher cytotoxicity than cyclophosphamide against A549 and MCF7 cancer cell lines. The IC50 value of 2 (29.24) is lower in the A549 cell line and slightly higher (18.04) in the MCF7 cell line than that of cyclophosphamide [IC50 = 41.84 (A549) and 11.89 μM (MCF7)].

  12. Determination of kinetic and equilibrium parameters of the batch adsorption of Mn(II), Co(II), Ni(II) and Cu(II) from aqueous solution by black carrot (Daucus carota L.) residues.

    PubMed

    Güzel, Fuat; Yakut, Hakan; Topal, Giray

    2008-05-30

    In this study, the effect of temperature on the adsorption of Mn(II), Ni(II), Co(II) and Cu(II) from aqueous solution by modified carrot residues (MCR) was investigated. The equilibrium contact times of adsorption process for each heavy metals-MCR systems were determined. Kinetic data obtained for each heavy metal by MCR at different temperatures were applied to the Lagergren equation, and adsorption rate constants (kads) at these temperatures were determined. These rate constants related to the adsorption of heavy metal by MCR were applied to the Arrhenius equation, and activation energies (Ea) were determined. In addition, the isotherms for adsorption of each heavy metal by MCR at different temperatures were also determined. These isothermal data were applied to linear forms of isotherm equations that they fit the Langmuir adsorption isotherm, and the Langmuir constants (qm and b) were calculated. b constants determined at different temperatures were applied to thermodynamic equations, and thermodynamic parameters such as enthalpy (Delta H), free energy (Delta G), and entropy (Delta S) were calculated and these values show that adsorption of heavy metal on MCR was an endothermic process and process of adsorption was favoured at high temperatures.

  13. Synthesis, Spectroscopic Characterization, and In Vitro Antimicrobial Studies of Pyridine-2-Carboxylic Acid N′-(4-Chloro-Benzoyl)-Hydrazide and Its Co(II), Ni(II), and Cu(II) Complexes

    PubMed Central

    Singh, Jagvir; Singh, Prashant

    2012-01-01

    N-substituted pyridine hydrazide (pyridine-2-carbonyl chloride and 4-chloro-benzoic acid hydrazide) undergoes hydrazide formation of the iminic carbon nitrogen double bond through its reaction with cobalt(II), nickel(II), and copper(II) metal salts in ethanol which are reported and characterized based on elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TG). From the elemental analyses data, 1 : 2 metal complexes are formed having the general formulae [MCl2(HL)2] ·yH2O (where M = Co(II), Ni(II), and Cu(II), y = 1–3). The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied. IR spectra show that ligand is coordinated to the metal ions in a neutral bidentate manner with ON donor sites. The solid complexes have been synthesized and studied by thermogravimetric analysis. All the metal chelates are found to be nonelectrolytes. From the magnetic and solid reflectance spectra, the complexes (cobalt(II), nickel(II), and copper(II)) have octahedral and square planner geometry, respectively. The antibacterial and antifungal activity's data show that the metal complexes have a promising biological activity comparable with the parent ligand against bacterial and fungal species. PMID:23125560

  14. Synthesis, spectral and electrochemical studies of Cu(II) and Ni(II) complexes with new N 2O 2 ligands: A new precursor capable of depositing copper nanoparticles using thermal reduction

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Mokhtari, Reza; Mikhak, Maryam; Amirnasr, Mehdi; Amiri, Ahmad

    2011-09-01

    Cu(II) and Ni(II) complexes of the general type [M(N 2O 2)] are described. The N 2O 2 ligands used are [N,N'-bis(2-hydroxy-6-methoxybenzylidene)propane-1,3-diamine] (HOMeSalpn) and [N,N'-bis(2-hydroxy-6-methoxybenzylidene)propane-1,2-diamine (HOMeSalpr). These complexes have been characterized by IR, UV-vis, CV, TG-DTA and 1H NMR spectroscopy. The electrochemical behavior of these complexes at a glassy carbon electrode in acetonitrile solution indicates that the first reduction process corresponding to Cu(II)-Cu(I) and Ni(II)-Ni(I) is electrochemically irreversible. The new copper complexes have been applied for the preparation of copper nanoparticles using non-ionic surfactant (Triton X-100) by thermal reduction. The copper nanoparticles with average size of 48 nm were formed by thermal reduction of [N,N'-bis(2-hydroxy-6-methoxybenzylidene)propane-1,3-diamine]copper(II) in the presence of triphenylphosphine thus releasing the reduced copper and affording the high-purity copper nanoparticles.

  15. Synthesis, characterization and equilibrium studies of some potential antimicrobial and antitumor complexes of Cu(II), Ni(II), Zn(II) and Cd(II) ions involving 2-aminomethylbenzimidazole and glycine

    NASA Astrophysics Data System (ADS)

    Aljahdali, M.

    2013-08-01

    The ternary complexes of Cu(II), Zn(II), Ni(II) and Cd(II) with 2-aminomethylbenzimidazole (AMBI) and glycine as a representative example of amino acids have been isolated and characterized by elemental analyses, IR, ESR, UV-vis, magnetic moment, molar conductance and 1H NMR spectra. AMBI behaves as neutral bidentate ligands with coordination through imidazole and amino group nitrogens while the glycine amino acid behaves as a monodenate anion with coordination involving the amino group and carboxylate oxygen after deprotonation. The magnetic and spectral data indicates a square planar geometry for both Cu2+ and Ni2+ complexes and a tetrahedral geometry for both Zn2+ and Cd2+ complexes. The isolated chelates have been screened for their antifungal and antibacterial activities using the disc diffusion method. A cytotoxicity of the compounds against colon (HCT116) and larynx (HEP2) cancer cells have been studied. The stability constants of ternary M-AMBI-Gly complexes were determined potentiometrically in aqueous solution at I = 0.1 mol dm-3 NaCl.

  16. 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

    NASA Astrophysics Data System (ADS)

    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.

  17. A multi-approach study of the interaction of the Cu(II) and Ni(II) ions with alanylglycylhistamine, a mimicking pseudopeptide of the serum albumine N-terminal residue.

    PubMed

    Gizzi, P; Henry, B; Rubini, P; Giroux, S; Wenger, E

    2005-05-01

    The protonation equilibria of alanylglycylhistamine (Ala-Gly-Ha) and the complexation of this ligand with Cu(II) and Ni(II) have been studied by pH-potentiometry, 1H and 14N NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), circular dichroism (CD), UV-Vis spectrophotometry and electron paramagnetic resonance (EPR). From pH approximately 2-12, the following complexes: MLH, MLH(-1), MLH(-2) and MLH(-3) are successively formed in aqueous solutions, the ligand under its neutral form being noted L. At physiological pH, the MLH(-2) complex is predominant. The coordination in this complex is assumed by one amino, two deprotonated peptide and one imidazole nitrogen atoms. The ESI-MS study confirmed the formation of the MLH(-1), MLH(-2) and MLH(-3) complexes. The structure of MLH(-2) was determined by single crystal X-ray analysis. CD and UV-Vis techniques allowed us to propose that the imidazole-N3 nitrogen acts as the anchor group for the coordination to the metal(II) ions rather than the amino group. At high pH values, the further deprotonation of the N-H imidazole group, leading to the formation of MLH(-3), occurs, as revealed by 1H NMR spectroscopy.

  18. N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide and its Co(II), Ni(II) and Cu(II) complexes: Synthesis, characterization, DFT computations, thermal decomposition, antioxidant and antitumor activity

    NASA Astrophysics Data System (ADS)

    Yeşilkaynak, Tuncay; Özpınar, Celal; Emen, Fatih Mehmet; Ateş, Burhan; Kaya, Kerem

    2017-02-01

    N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide (HL: C11H8ClN3O2S) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analysis, FT-IR,1H NMR and HR-MS methods. The HL was characterized by single crystal X-ray diffraction technique. It crystallizes in the monoclinic system. The HL has the space group P 1 21/c 1, Z = 4, and its unit cell parameters are a = 4.5437(5) Å, b = 22.4550(3) Å, c = 11.8947(14) Å. The ligand coordinates the metal ions as bidentate and thus essentially yields neutral complexes of the [ML2] type. ML2 complex structures were optimized using B97D/TZVP level. Molecular orbitals of both HL ligand were calculated at the same level. Thermal decomposition of the complexes has been investigated by thermogravimetry. The complexes were screened for their anticancer and antioxidant activities. Antioxidant activity of the complexes was determined by using the DPPH and ABTS assays. The anticancer activity of the complexes was studied by using MTT assay in MCF-7 breast cancer cells.

  19. Syntheses, spectroscopic characterization, thermal study, molecular modeling, and biological evaluation of novel Schiff's base benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) with Ni(II), and Cu(II) metal complexes.

    PubMed

    Chandra, Sulekh; Gautam, Seema; Rajor, Hament Kumar; Bhatia, Rohit

    2015-02-25

    Novel Schiff's base ligand, benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) was synthesized by the condensation of benzil and 5-amino-1,3,4-thiadiazole-2-thiol in 1:2 ratio. The structure of ligand was determined on the basis of elemental analyses, IR, (1)H NMR, mass, and molecular modeling studies. Synthesized ligand behaved as tetradentate and coordinated to metal ion through sulfur atoms of thiol ring and nitrogen atoms of imine group. Ni(II), and Cu(II) complexes were synthesized with this nitrogen-sulfur donor (N2S2) ligand. Metal complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic spectra, EPR, thermal, and molecular modeling studies. All the complexes showed molar conductance corresponding to non-electrolytic nature, expect [Ni(L)](NO3)2 complex, which was 1:2 electrolyte in nature. [Cu(L)(SO4)] complex may possessed square pyramidal geometry, [Ni(L)](NO3)2 complex tetrahedral and rest of the complexes six coordinated octahedral/tetragonal geometry. Newly synthesized ligand and its metal complexes were examined against the opportunistic pathogens. Results suggested that metal complexes were more biological sensitive than free ligand.

  20. Synthesis, spectral and electrochemical studies of Cu(II) and Ni(II) complexes with new N2O2 ligands: a new precursor capable of depositing copper nanoparticles using thermal reduction.

    PubMed

    Habibi, Mohammad Hossein; Mokhtari, Reza; Mikhak, Maryam; Amirnasr, Mehdi; Amiri, Ahmad

    2011-09-01

    Cu(II) and Ni(II) complexes of the general type [M(N2O2)] are described. The N2O2 ligands used are [N,N'-bis(2-hydroxy-6-methoxybenzylidene)propane-1,3-diamine] (HOMeSalpn) and [N,N'-bis(2-hydroxy-6-methoxybenzylidene)propane-1,2-diamine (HOMeSalpr). These complexes have been characterized by IR, UV-vis, CV, TG-DTA and 1H NMR spectroscopy. The electrochemical behavior of these complexes at a glassy carbon electrode in acetonitrile solution indicates that the first reduction process corresponding to Cu(II)-Cu(I) and Ni(II)-Ni(I) is electrochemically irreversible. The new copper complexes have been applied for the preparation of copper nanoparticles using non-ionic surfactant (Triton X-100) by thermal reduction. The copper nanoparticles with average size of 48nm were formed by thermal reduction of [N,N'-bis(2-hydroxy-6-methoxybenzylidene)propane-1,3-diamine]copper(II) in the presence of triphenylphosphine thus releasing the reduced copper and affording the high-purity copper nanoparticles.

  1. Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS).

    PubMed

    Duran, Celal; Gundogdu, Ali; Bulut, Volkan Numan; Soylak, Mustafa; Elci, Latif; Sentürk, Hasan Basri; Tüfekci, Mehmet

    2007-07-19

    A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L(-1) HNO3 in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 microg L(-1). The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

  2. Synthesis and characterization of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based azo-linked Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Anitha, C.; Sheela, C. D.; Tharmaraj, P.; Johnson Raja, S.

    2012-12-01

    Azo-Schiff-base complexes of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized and characterized by elemental analysis, IR, UV-Vis, 1H NMR, mass spectra, molar conductance, magnetic susceptibility measurement, electron spin resonance (EPR), CV, fluorescence, NLO and SEM. The conductance data indicate the nonelectrolytic nature of the complexes, except VO(II) complex which is electrolytic in nature. On the basis of electronic spectra and magnetic susceptibility octahedral geometry has been proposed for the complexes. The EPR spectra of copper and oxovanadium complexes in DMSO at 300 and 77 K were recorded and its salient features are reported. The redox behavior of the copper(II) complex was studied using cyclic voltammetry. The in vitro antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella enterica typhi, Bacillus subtilis and Candida strains was studied and compared with that of free ligand by well-diffusion technique. The azo Schiff base exhibited fluorescence properties originating from intraligand (π-π∗) transitions and metal-mediated enhancement is observed on complexation and so the synthesized complexes can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. On the basis of the optimized structures, the second-order nonlinear optical properties (NLO) are calculated by using second-harmonic generation (SHG) and also the surface morphology of the complexes was studied by SEM.

  3. Synthesis, Spectroscopic Characterization, and In Vitro Antimicrobial Studies of Pyridine-2-Carboxylic Acid N'-(4-Chloro-Benzoyl)-Hydrazide and Its Co(II), Ni(II), and Cu(II) Complexes.

    PubMed

    Singh, Jagvir; Singh, Prashant

    2012-01-01

    N-substituted pyridine hydrazide (pyridine-2-carbonyl chloride and 4-chloro-benzoic acid hydrazide) undergoes hydrazide formation of the iminic carbon nitrogen double bond through its reaction with cobalt(II), nickel(II), and copper(II) metal salts in ethanol which are reported and characterized based on elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TG). From the elemental analyses data, 1 : 2 metal complexes are formed having the general formulae [MCl(2)(HL)(2)] ·yH(2)O (where M = Co(II), Ni(II), and Cu(II), y = 1-3). The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied. IR spectra show that ligand is coordinated to the metal ions in a neutral bidentate manner with ON donor sites. The solid complexes have been synthesized and studied by thermogravimetric analysis. All the metal chelates are found to be nonelectrolytes. From the magnetic and solid reflectance spectra, the complexes (cobalt(II), nickel(II), and copper(II)) have octahedral and square planner geometry, respectively. The antibacterial and antifungal activity's data show that the metal complexes have a promising biological activity comparable with the parent ligand against bacterial and fungal species.

  4. Antimicrobial, spectral, magnetic and thermal studies of Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes of the Schiff base derived from oxalylhydrazide.

    PubMed

    Melha, Khlood Abou

    2008-04-01

    The Schiff base ligand, oxalyl [( 2 - hydroxybenzylidene) hydrazone] [corrected].H(2)L, and its Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes were prepared and tested as antibacterial agents. The Schiff base acts as a dibasic tetra- or hexadentate ligand with metal cations in molar ratio 1:1 or 2:1 (M:L) to yield either mono- or binuclear complexes, respectively. The ligand and its metal complexes were characterized by elemental analyses, IR, (1)H NMR, Mass, and UV-Visible spectra and the magnetic moments and electrical conductance of the complexes were also determined. For binuclear complexes, the magnetic moments are quite low compared to the calculated value for two metal ions complexes and this shows antiferromagnetic interactions between the two adjacent metal ions. The ligand and its metal complexes were tested against a Gram + ve bacteria (Staphylococcus aureus), a Gram -ve bacteria (Escherichia coli), and a fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.

  5. Chitosan film loaded with silver nanoparticles-sorbent for solid phase extraction of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II).

    PubMed

    Djerahov, Lubomir; Vasileva, Penka; Karadjova, Irina; Kurakalva, Rama Mohan; Aradhi, Keshav Krishna

    2016-08-20

    The present study describes the ecofriendly method for the preparation of chitosan film loaded with silver nanoparticles (CS-AgNPs) and application of this film as efficient sorbent for separation and enrichment of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II). The stable CS-AgNPs colloid was prepared by dispersing the AgNPs sol in chitosan solution at appropriate ratio and further used to obtain a cast film with very good stability under storage and good mechanical strength for easy handling in aqueous medium. The incorporation of AgNPs in the structure of CS film and interaction between the polymer matrix and nanoparticles were confirmed by UV-vis and FTIR spectroscopy. The homogeneously embedded AgNPs (average diameter 29nm, TEM analysis) were clearly observed throughout the film by SEM. The CS-AgNPs nanocomposite film shows high sorption activity toward trace metals under optimized chemical conditions. The results suggest that the CS-AgNPs nanocomposite film can be feasibly used as a novel sorbent material for solid-phase extraction of metal pollutants from surface waters.

  6. 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

    NASA Astrophysics Data System (ADS)

    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.

  7. Synthesis, DNA-binding, DNA-photonuclease profiling and antimicrobial activity of novel tetra-aza macrocyclic Ni(II), Co(II) and Cu(II) complexes constrained by thiadiazole.

    PubMed

    Vinay Kumar, B; Bhojya Naik, H S; Girija, D; Sharath, N; Pradeepa, S M; Joy Hoskeri, H; Prabhakara, M C

    2012-08-01

    A new tetra-aza macrocyclic ligand, L (C(24)H(16)N(12)O(2)S(4)) and its complexes of type, [MLCl(2)] and [CuL]Cl(2) (where M=Ni(II), Co(II); L=N,N'-(benzene-1,3-diyldi-1,3,4-thiadiazole-5,2-diyl)bis{2-[(5-benzene-1,3-diyl-1,3,4-thiadiazol-2-yl)amino]acetamide}) were synthesized and characterized by the spectral and analytical techniques. An octahedral geometry has been proposed for Ni(II) and Co(II) complexes while Cu(II) complex exhibit a square planar geometry. All the synthesized metal complexes were screened for their in vitro antimicrobial activity against selected species of pathogenic bacteria and fungi. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. The photo induced cleavage studies revealed that the complexes possess photonuclease property against pUC19 DNA under UV-visible irradiation.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Dinuclear Metallacycles with Single M-X-M Bridges (X = Cl(-), Br(-); M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)): Strong Antiferromagnetic Superexchange Interactions.

    PubMed

    Reger, Daniel L; Pascui, Andrea E; Foley, Elizabeth A; Smith, Mark D; Jezierska, Julia; Wojciechowska, Agnieszka; Stoian, Sebastian A; Ozarowski, Andrew

    2017-03-06

    A series of monochloride-bridged, dinuclear metallacycles of the general formula [M2(μ-Cl)(μ-L)2](ClO4)3 have been prepared using the third-generation, ditopic bis(pyrazolyl)methane ligands L = m-bis[bis(1-pyrazolyl)methyl]benzene (Lm), M = Cu(II), Zn(II), and L = m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*), M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). These complexes were synthesized from the direct reactions of M(ClO4)2·6H2O, MCl2, and the ligand, Lm or Lm*, in the appropriate stoichiometric amounts. Three analogous complexes of the formula [M2(μ-Cl)(μ-L)2](BF4)3, L = Lm, M = Cu(II), and L = Lm*, M = Co(II), Cu(II), were prepared from the reaction of [M2(μ-F)(μ-L)2](BF4)3 and (CH3)3SiCl. The bromide-bridged complex [Cu2(μ-Br)(μ-Lm*)2](ClO4)3 was prepared by the first method. Three acyclic complexes, [Co2(μ-Lm)μ-Cl4], [Co2(μ-Lm*)Cl4], and [Co2(μ-Lm*)Br4], were also prepared. The structures of all [M2(μ-X)(μ-L)2](3+) (X = Cl(-), Br(-)) complexes have two ditopic bis(pyrazolyl)methane ligands bridging two metals in a metallacyclic arrangement. The fifth coordination site of the distorted trigonal bipyramidal metal centers is filled by a bridging halide ligand that has an unusual linear or nearly linear M-X-M angle. The NMR spectra of [Zn2(μ-Cl)(μ-Lm*)2](ClO4)3 and especially [Cd2(μ-Cl)(μ-Lm*)2](ClO4)3 demonstrate that the metallacycle structure is maintained in solution. Solid state magnetic susceptibility data for the copper(II) compounds show very strong antiferromagnetic exchange interactions, with -J values of 536 cm(-1) for [Cu2(μ-Cl)(μ-Lm)2](ClO4)3·xCH3CN, 720 cm(-1) for [Cu2(μ-Cl)(μ-Lm*)2](ClO4)3, and 945 cm(-1) for [Cu2(μ-Br)(μ-Lm*)2](ClO4)3·2CH3CN. Smaller but still substantial antiferromagnetic interactions are observed with other first row transition metals, with -J values of 98 cm(-1) for [Ni2(μ-Cl)(μ-Lm*)2](ClO4)3, 55 cm(-1) for [Co2(μ-Cl)(μ-Lm*)2](ClO4)3, and 34 cm(-1) for [Fe2(μ-Cl)(μ-Lm*)2](ClO4

  10. Metal-Based Antibacterial and Antifungal Agents: Synthesis, Characterization, and In Vitro Biological Evaluation of Co(II), Cu(II), Ni(II), and Zn(II) Complexes With Amino Acid-Derived Compounds

    PubMed Central

    Chohan, Zahid H.; Arif, M.; Akhtar, Muhammad A.; Supuran, Claudiu T.

    2006-01-01

    A series of antibacterial and antifungal amino acid-derived compounds and their cobalt(II), copper(II), nickel(II), and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, and IR, and electronic spectral measurements. Ligands (L1)−(L5) were derived by condensation of β-diketones with glycine, phenylalanine, valine, and histidine and act as bidentate towards metal ions (cobalt, copper, nickel, and zinc) via the azomethine-N and deprotonated-O of the respective amino acid. The stoichiometric reaction between the metal(II) ion and synthesized ligands in molar ratio of M : L (1 : 1) resulted in the formation of the metal complexes of type [M(L)(H2O)4]Cl (where M = Co(II), Cu(II), and Zn(II)) and of M : L (1 : 2) of type [M(L)2(H2O)2] (where M = Co(II), Cu(II), Ni(II), and Zn(II)). The magnetic moment data suggested for the complexes to have an octahedral geometry around the central metal atom. The electronic spectral data also supported the same octahedral geometry of the complexes. Elemental analyses and NMR spectral data of the ligands and their metal(II) complexes agree with their proposed structures. The synthesized ligands, along with their metal(II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The results of these studies show the metal(II) complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Five compounds, (3), (7), (10), (11), and (22), displayed

  11. Template Synthesis of Co(II), Ni(II) and Cu(II) Complexes Derived From Oxamide Ligand and the Reactivity of Cu(II) Complex Towards Human Serum Albumin

    PubMed Central

    Mohani, Bhawana; Arjmand, Farukh

    2004-01-01

    A new oxamide ligand 2,2'-(oxalydimino)bis(diacetic acid)[C10H11O10N2],[L] has been synthesized by the condensation reaction of Iminodiacetic acid and Diethyloxalate. This ligand [L] was further allowed to interact with triethylene-tetraamine metal complexes [C16H26N6O8M]Cl2 (where M=Co11, Ni11 and Cu11) to yield the new N4 macrocyclic complexes 3, 3', 6, 6' tetraazadodeca 1-1' diimino N N tetraacetic acid M) chloride ([C16H26N6O8Co]Cl2, [C16H26N6O8Ni]Cl2 and [C16H26N6O8Cu]Cl2). These complexes were characterized by elemental analyses, i.r., n.m.r., e.p.r, and u.v.-vis spectroscopy. All the complexes show square planar geometry and are ionic in nature. The kinetic studies of the Cu(lI) complex were ascertained spectrophotometrically by observing the absorbance changes in presence of protein Human Serum Albumin (HSA) in phosphate buffer at different pH's at 300C. The absorbance changes were monitored at 278 nm (λmax of HSA) with respect to time and pseudo-first-order rate constants, kobs, were obtained from the slope of the straight line using the least squares regression method. The electrochemical behaviour of the Cu(ll) complex was monitored by cyclic voltammetry in a phosphate buffer. The Ep values-0.730 and-0.560 V respectively, were obtained at the scan rate of 0.1 Vs-1. The interaction of the Cu(II) complex with the HSA was studied at the same scan rate, which reveals weak binding as the E0 values do not shift considerably. The cyclic voltammogram of the Cu(II) complex bound to HSA was recorded at different pH's also (6.5 to 7.4). The pH-rate profile data reveals that the reactions are pH dependent. PMID:18365078

  12. Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol

    NASA Astrophysics Data System (ADS)

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B. S.; Yadav, Deepak

    2015-06-01

    A series of two biologically active Schiff base ligands L1, L2 have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by 1H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7.

  13. Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol.

    PubMed

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S; Yadav, Deepak

    2015-06-15

    A series of two biologically active Schiff base ligands L(1), L(2) have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by (1)H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7.

  14. Synthesis, spectral characterization, structural investigation and antimicrobial studies of mononuclear Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of a new potentially hexadentate N2O4 Schiff base ligand derived from salicylaldehyde

    NASA Astrophysics Data System (ADS)

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Elerman, Yalcin; Buyukgungor, Orhan

    2013-01-01

    A new potentially hexadentate N2O4 Schiff base ligand, H2L derived from condensation reaction of an aromatic diamine and salicylaldehyde, and its metal complexes were characterized by elemental analyses, IR, UV-Vis, EI-MS, 1H and 13C NMR spectra, as well as conductance measurements. It has been originated that the Schiff base ligand with Cu(II), Ni(II), Co(II), Cd(II) and Zn(II) ions form mononuclear complexes on 1:1 (metal:ligand) stoichiometry. The conductivity data confirm the non-electrolytic nature of the complexes. Also the crystal structures of the complexes [ZnL] and [CoL] have also been determined by using X-ray crystallographic technique. The Zn(II) and Co(II) complexes show a tetrahedral configuration. Electronic absorption spectra of the Cu(II) and Ni(II) complexes suggest a square-planar geometry around the central metal ion. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Bacillus cereus, Enterococcus faecalis and Listeria monocytogenes and also against the three Gram-negative bacteria: Salmonella paraB, Citrobacter freundii and Enterobacter aerogenes. The results showed that in some cases the antibacterial activity of complexes were more than nalidixic acid and amoxicillin as standards.

  15. Preparation and Characterization of Bi-metallic and Tri-metallic Metal Organic Frameworks Based on Trimesic Acid and Co(II), Ni(II), and Cu(II) Ions

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Demirci, Sahin; Yildiz, Mustafa

    2017-02-01

    Trimesic acid-M1(II):M2(II) (M1,2(II)=M(II)=Co(II), Ni(II) and Cu(II)) bi-metallic or tri-metallic organic frameworks (MOFs) were synthesized by the reaction of trimesic acid (H3BTC) ligand with the corresponding MCl2nH2O aqueous solutions. Here, bi- and tri-metallic MOF preparations were demonstrated by using H3BTC as an organic linker, with dual metal ion mixtures at different mole ratios such as Co(II):Ni(II), Ni(II):Cu(II), and Cu(II):Co(II) as metal ion sources in the synthesis of bi-metallic MOFs, and the triple metal ion mixture of Co(II):Ni(II):Cu(II) as the metal ion source in the synthesis of tri-metallic MOFs. The bi- or tri-metallic MOFs were characterized via the Brunauer-Emmett-Teller method, thermogravimetric analyzer (TGA), and magnetic susceptibility measurements with the Gouy method, FT-IR spectroscopy, and electronic spectral studies. The results revealed that the H3BTC MOFs have octahedral and distorted octahedral arrangement around the metal ions, and the d-d transition was not observed in the complex. It was further found that all the prepared MOFs contain water molecules confirmed by Fourier transform infrared (FT-IR) and TGA analyses. The FT-IR spectra of the MOF complexes were characterized by the appearance of a broad band in the region of 3454-3300 cm-1 due to the ν(-OH) of the coordinated water; therefore, the location of the two water molecules was assumed to be inside the complex structure. Remarkably, the synthesized bi-metallic MOFs had unique and distinct colors depending on the amounts of metal ions used in the feed, implying that these bi-metallic MOFs with tunable M1(II) and M2(II) ratios offer great potential in the design of color-coded materials for use as sensors.

  16. Thermal- and pressure-induced cooperative spin transition in the 2D and 3D coordination polymers {Fe(5-Br-pmd)z[M(CN)x]y} (M=AgI, AuI, NiII, PdII, PtII).

    PubMed

    Agustí, Gloria; Gaspar, Ana Belén; Muñoz, M Carmen; Real, José Antonio

    2007-11-12

    A new family of cyanide-based spin-crossover polymers with the general formula {Fe(5-Br-pmd)z[M(CN)x]y} [M=AgI (1), AuI (2), NiII (3), PdII (4), PtII (5); 5-Br-pmd=5-bromopyrimidine; z=1 or 2, x=2 or 4, and y=2 or 1] have been synthesized and characterized using single-crystal X-ray diffraction (XRD), X-ray powder diffraction (XRPD), magnetic susceptibility measurements, and differential scanning calorimetry (DSC). At 293 K, compound 1 presents the monoclinic space group C2/c, whereas at 120 K, it changes to the monoclinic space group P21/c. At 293 K, the crystal structure of 1 displays an uninodal three-dimensional network whose nodes, constituted of FeII, lie at the inversion center of an elongated octahedron. The equatorial bond lengths are defined by the N atoms of four [AgI(CN)2]- groups belonging to two crystallographically nonequivalent AgI atoms, Ag(1) and Ag(2). They are shorter than those of the axial positions occupied by the N atoms of the 5-Br-pmd ligands. The Fe-N average bond length of 2.1657(7) A is consistent with a high-spin (HS) state for the FeII ions. At 120 K, the crystal structure changes refer mainly to the FeII environment. There are two crystallographically independent FeII ions at this temperature, Fe(1) and Fe(2), which adopt the HS and low-spin (LS) states, respectively. The average Fe-N bond length for Fe(1) [2.174(5) A] and Fe(2) [1.955(5) A] agrees well with the reported magnetic data at this temperature. The spin transition of the FeII ions labeled as Fe(1) is found to be centered at Tc downward arrow=149 K and Tc upward arrow=167 K and accompanied by a drastic change of color from orange (HS) to red (LS). Magnetic susceptibility measurements under applied hydrostatic pressure performed on 1 have shown a linear displacement of the transition to higher temperatures while the hysteresis width remains unaltered in the interval of pressures of 105 Pa to 0.34 GPa. A further increase of the pressure induces the spin transition in the Fe(2

  17. Synthesis, spectral and quantum chemical studies and use of (E)-3-[(3,5-bis(trifluoromethyl)phenylimino)methyl]benzene-1,2-diol and its Ni(II) and Cu(II) complexes as an anion sensor, DNA binding, DNA cleavage, anti-microbial, anti-mutagenic and anti-cancer agent

    NASA Astrophysics Data System (ADS)

    Ünver, Hüseyin; Boyacıoğlu, Bahadır; Zeyrek, Celal Tuğrul; Yıldız, Mustafa; Demir, Neslihan; Yıldırım, Nuray; Karaosmanoğlu, Oğuzhan; Sivas, Hülya; Elmalı, Ayhan

    2016-12-01

    We report the synthesis of a novel Schiff base (E)-3-[(3,5-bis(trifluoromethyl) phenylimino)methyl] benzene-1,2-diol from the reaction of 2,3-dihydroxybenzaldehyde with 3,5-bis(trifluoromethyl)aniline, and its Ni(II) and Cu(II) complexes. The molecular structure of the Schiff base was experimentally determined using X-ray single-crystal data and was compared to the structure predicted by theoretical calculations using density functional theory (DFT), Hartree-Fock (HF) and Möller-Plesset second-order perturbation (MP2). In addition, nonlinear optical (NLO) effects of the compound was predicted using DFT. The antimicrobial activities of the compounds were investigated for their minimum inhibitory concentration. UV-Vis spectroscopy studies of the interactions between the compounds and calf thymus DNA (CT-DNA) showed that the compounds interacts with CT-DNA via intercalative binding. A DNA cleavage study showed that the Cu(II) complex cleaved DNA without any external agents. The compounds inhibited the base pair mutation in the absence of S9 with high inhibition rate. In addition, in vitro cytotoxicity of the Ni(II) complex towards HepG2 cell line was assayed by the MTT method. Also, the colorimetric response of the Schiff base in DMSO to the addition of equivalent amount of anions (F-, Br-, I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4-, N3- and OH-) was investigated. In this regard, while the addition of F-, CN-, AcO- and OH- anions into the solution containing Schiff base resulted in a significant color change, the addition of Br-, I-, SCN-, ClO4-, HSO4-, H2PO4- and N3- anions resulted in no color change. The most discernable color change in the Schiff base was caused by CN-, which demonstrated that the ligand can be used to selectively detect CN-.

  18. Syntheses, spectroscopic and thermal analyses of cyanide bridged heteronuclear polymeric complexes: [M(L)2Ni(CN)4]n (Ldbnd N-methylethylenediamine or N-ethylethylenediamine; Mdbnd Ni(II), Cu(II), Zn(II) or Cd(II))

    NASA Astrophysics Data System (ADS)

    Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla

    2016-02-01

    Polymeric tetracyanonickelate(II) complexes of the type [M(L)2Ni(CN)4]n (Ldbnd N-methylethylenediamine (men) or N-ethylethylenediamine (neen); Mdbnd Ni(II), Cu(II), Zn(II) or Cd(II)) have been prepared and characterized by FT-IR, Raman spectroscopy, thermal and elemental analysis techniques. Additionally, FT-IR and Raman spectral analyses of men and neen have experimentally and theoretically investigated in the range of 4000-250 cm-1. The corresponding vibration assignments of men and neen are performed by using B3LYP density functional theory (DFT) method together with 6-31 G(d) basis set. The spectral features of the complexes suggest that the coordination environment of the M(II) ions are surrounded by the two symmetry related men and neen ligands and the two symmetry related N atom of cyanide groups, whereas the Ni(II) atoms are coordinated with a square-planar to four C atoms of the cyanide groups. Polymeric structures of the complexes consist of one dimensional alternative chains of [M(L)2]2+ and [Ni(CN)4]2- moieties. The thermal decompositions in the temperature range 30-700 °C of the complexes were investigated in the static air atmosphere.

  19. Sonochemical synthesis, DNA binding, antimicrobial evaluation and in vitro anticancer activity of three new nano-sized Cu(II), Co(II) and Ni(II) chelates based on tri-dentate NOO imine ligands as precursors for metal oxides.

    PubMed

    Abdel-Rahman, Laila H; Abu-Dief, Ahmed M; El-Khatib, Rafat M; Abdel-Fatah, Shimaa Mahdy

    2016-09-01

    Three new nano sized Cu(II), Co(II) and Ni(II) complexes of imine ligand derived from the condensation of 2-amino-3-hydroxypyridine and 3-methoxysalicylaldehyde have been prepared and investigated using various chemical techniques such as NMR, elemental analysis, molar conductance, IR, electronic spectra, TGA and magnetic moment measurements. The obtained chemical analysis data showed that the synthesis of 1:1 (metal:ligand) ratio and octahedral geometry was proposed on the basis of magnetic moment and spectral data studies except the Cu(II) complex which is tetrahedral geometry. Nano-sized particles of the investigated complexes were prepared by sonochemistry method. Furthermore, metal oxides nanoparticles were gained by calcination of the prepared corresponding complexes at 500°C and their structures were characterized by powder x-ray and transmittance electron microscopy. Moreover, the free ligand, its complexes and their metal oxides have been checked in vitro against a number of bacteria and fungi in order to assess their antimicrobial activities. In addition to that, DNA binding of the prepared complexes was tested by many routes such as electronic spectra, viscosity and gel electrophoresis. The results showed that the investigated complexes could bind to DNA via an intercalative mode. The cytotoxicity of the Schiff base complexes on human colon carcinoma cells, (HCT-116 cell line) and Breast carcinoma cells, (MCF-7 cell line) showed potent cytotoxicity effect against growth of carcinoma cells compared to the clinically used Vinblastine standard.

  20. Cu(II), Co(II), Ni(II), Mn(II), and Fe(II) metal complexes containing N,N'-(3,4-diaminobenzophenon)-3,5-Bu t2-salicylaldimine ligand: Synthesis, structural characterization, thermal properties, electrochemistry, and spectroelectrochemistry

    NASA Astrophysics Data System (ADS)

    Tas, E.; Kilic, A.; Durgun, M.; Küpecik, L.; Yilmaz, I.; Arslan, S.

    2010-02-01

    The synthesis, structure, spectroscopic and electro-spectrochemical properties of steric hindered Schiff-base ligand [ N,N'-(3,4-benzophenon)-3,5-Bu t2-salicylaldimine (LH 2)] and its mononuclear Cu(II), Co(II), Ni(II), Mn(II) and Fe(II) complexes are described in this work. The new dissymmetric steric hindered Schiff-base ligand containing a donor set of NONO was prepared through reaction of 3,4-diaminobenzophenon with 3,5-Bu t2-salicylaldehyde. Certain metal complexes of this ligand were synthesized by treating an ethanolic solution of the ligand with an equimolar amount of metal salts. The ligand and its complexes were characterized by FT-IR, UV-vis, 1H NMR, elemental analysis, molar conductivity and thermal analysis methods in addition to magnetic susceptibility, electrochemistry and spectroelectrochemistry techniques. The tetradentate and mononuclear metal complexes were obtained by reacting N,N'-(3,4-benzophenon)-3,5-Bu t2-salicylaldimine (LH 2) with some metal acetate in a 1:1 mole ratio. The molar conductance data suggest metal complexes to be non-electrolytes.

  1. Synthesis, Characterization, and Biological Activity of N (')-[(Z)-(3-Methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)(phenyl)methyl]benzohydrazide and Its Co(II), Ni(II), and Cu(II) Complexes.

    PubMed

    Asegbeloyin, Jonnie N; Ujam, Oguejiofo T; Okafor, Emmanuel C; Babahan, Ilknur; Coban, Esin Poyrazoglu; Ozmen, Ali; Biyik, Halil

    2014-01-01

    Reaction of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one and benzoyl hydrazide in refluxing ethanol gave N (')-[(Z)-(3-methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)(phenyl)methyl]benzohydrazide (HL(1)), which was characterized by NMR spectroscopy and single-crystal X-ray structure study. X-ray diffraction analyses of the crystals revealed a nonplanar molecule, existing in the keto-amine form, with intermolecular hydrogen bonding forming a seven-membered ring system. The reaction of HL(1) with Co(II), Ni(II), and Cu(II) halides gave the corresponding complexes, which were characterized by elemental analysis, molar conductance, magnetic measurements, and infrared and electronic spectral studies. The compounds were screened for their in vitro cytotoxic activity against HL-60 human promyelocytic leukemia cells and antimicrobial activity against some bacteria and yeasts. Results showed that the compounds are potent against HL-60 cells with the IC50 value ≤5 μM, while some of the compounds were active against few studied Gram-positive bacteria.

  2. Another step toward DNA selective targeting: NiII and CuII complexes of a Schiff base ligand able to bind gene promoter G-quadruplexes† †Electronic supplementary information (ESI) available. CCDC 1451694–1451696. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6dt00648e Click here for additional data file. Click here for additional data file.

    PubMed Central

    Lötsch, Daniela; van Schoonhoven, Sushilla; Roller, Alexander; Kowol, Christian R.; Berger, Walter; Keppler, Bernhard K.

    2016-01-01

    DNA G-rich sequences are able to form four-stranded structures organized in stacked guanine tetrads. These structures, called G-quadruplexes, were found to have an important role in the regulation of oncogenes expression and became, for such a reason, appealing targets for anticancer drugs. Aiming at finding selective G-quadruplex binders, we have designed, synthesized and characterized a new water soluble Salen-like Schiff base ligand and its NiII and CuII metal complexes. UV-Vis, circular dichroism and FRET measurements indicated that the nickel complex can stabilize oncogene promoter G-quadruplexes with high selectivity, presenting no interactions with duplex DNA at all. The same compound exhibited dose-dependent cytotoxic activity in MCF-7 breast cancer cells when combined with lipofectamine as lipophilic carrier. PMID:27054617

  3. Pharmacologically significant complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) of novel Schiff base ligand, (E)-N-(furan-2-yl methylene) quinolin-8-amine: Synthesis, spectral, XRD, SEM, antimicrobial, antioxidant and in vitro cytotoxic studies

    NASA Astrophysics Data System (ADS)

    Shakir, M.; Hanif, Summaiya; Sherwani, Mohd. Asif; Mohammad, Owais; Al-Resayes, Saud I.

    2015-07-01

    A novel series of metal complexes of the types, [ML2(H2O)2]Cl2 and [ML2]Cl2 [M = Mn(II), 1; Co(II), 2; Ni(II), 3; Cu(II), 4; and Zn(II), 5] were synthesized by the interaction of ligand, L (E)-N-(furan-2-yl methylene) quinolin-8-amine, derived from the condensation of 2-furaldehyde and 8-aminoquinoline. The synthesized ligand and its metal complexes were characterized on the basis of results obtained from elemental analysis, ESI-MS, XRD, SEM, TGA/DTA, FT-IR, UV-Vis, magnetic moment and 1H and 13C NMR spectroscopic studies. EPR parameters were recorded in case of complex 4. The comparative in-vitro antimicrobial activities against various pathogens with reference to known antibiotics and antioxidant activity against standard control at variable concentrations revealed that the metal complexes show enhanced antimicrobial and free radical scavenging activities in general as compared to free ligand. However, the complexes 1 and 5 have shown best antioxidant activity among all the metal complexes. Furthermore, comparative in-vitro antiproliferative activity on ligand and its metal chelates performed on MDA-MB-231 (breast carcinoma), KCL22 (blood lymphoid carcinoma), HeLa (cervical carcinoma) cell lines and normal cells (PBMC) revealed that metal chelates show moderate to good activity as compared to ligand where as complex 1 seems to be the most promising one possessing a broad spectrum of activity against all the selected cancer cell lines with IC50 < 2.10 μM.

  4. Ligational behaviour of lomefloxacin drug towards Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Th(IV) and UO(2)(VI) ions: synthesis, structural characterization and biological activity studies.

    PubMed

    Abd el-Halim, Hanan F; Mohamed, Gehad G; el-Dessouky, Maher M I; Mahmoud, Walaa H

    2011-11-01

    Nine new mononuclear Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Th(IV) and UO(2)(VI) complexes of lomefloxacin drug were synthesized. The structures of these complexes were elucidated by elemental analyses, IR, XRD, UV-vis, (1)H NMR as well as conductivity and magnetic susceptibility measurements and thermal analyses. The dissociation constants of lomefloxacin and stability constants of its binary complexes have been determined spectrophotometrically in aqueous solution at 25±1°C and at 0.1 M KNO(3) ionic strength. The discussion of the outcome data of the prepared complexes indicate that the lomefloxacin ligand behaves as a neutral bidentate ligand through OO coordination sites and coordinated to the metal ions via the carbonyl oxygen and protonated carboxylic oxygen with 1:1 (metal:ligand) stoichiometry for all complexes. The molar conductance measurements proved that the complexes are electrolytes. The powder XRD study reflects the crystalline nature for the investigated ligand and its complexes except Mn(II), Zn(II) and UO(2)(II). The geometrical structures of these complexes are found to be octahedral. The thermal behaviour of these chelates is studied where the hydrated complexes lose water molecules of hydration in the first steps followed by decomposition of the anions, coordinated water and ligand molecules in the subsequent steps. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. A comparative study of the inhibition zones of the ligand and its metal complexes indicates that metal complexes exhibit higher antibacterial effect against one or more bacterial species than the free LFX ligand. The antifungal and anticancer activities were also tested. The antifungal effect of almost metal complexes is higher than the free ligand. LFX, [Co(LFX)(H(2)O)(4)]·Cl(2) and [Zn(LFX)(H(2)O)(4)]·Cl(2) were found to be very active with IC50 values 14, 11.2 and 43.1, respectively. While, other

  5. Ligational behaviour of lomefloxacin drug towards Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Th(IV) and UO 2(VI) ions: Synthesis, structural characterization and biological activity studies

    NASA Astrophysics Data System (ADS)

    El-Halim, Hanan F. Abd; Mohamed, Gehad G.; El-Dessouky, Maher M. I.; Mahmoud, Walaa H.

    2011-11-01

    Nine new mononuclear Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Th(IV) and UO 2(VI) complexes of lomefloxacin drug were synthesized. The structures of these complexes were elucidated by elemental analyses, IR, XRD, UV-vis, 1H NMR as well as conductivity and magnetic susceptibility measurements and thermal analyses. The dissociation constants of lomefloxacin and stability constants of its binary complexes have been determined spectrophotometrically in aqueous solution at 25 ± 1 °C and at 0.1 M KNO 3 ionic strength. The discussion of the outcome data of the prepared complexes indicate that the lomefloxacin ligand behaves as a neutral bidentate ligand through OO coordination sites and coordinated to the metal ions via the carbonyl oxygen and protonated carboxylic oxygen with 1:1 (metal:ligand) stoichiometry for all complexes. The molar conductance measurements proved that the complexes are electrolytes. The powder XRD study reflects the crystalline nature for the investigated ligand and its complexes except Mn(II), Zn(II) and UO 2(II). The geometrical structures of these complexes are found to be octahedral. The thermal behaviour of these chelates is studied where the hydrated complexes lose water molecules of hydration in the first steps followed by decomposition of the anions, coordinated water and ligand molecules in the subsequent steps. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. A comparative study of the inhibition zones of the ligand and its metal complexes indicates that metal complexes exhibit higher antibacterial effect against one or more bacterial species than the free LFX ligand. The antifungal and anticancer activities were also tested. The antifungal effect of almost metal complexes is higher than the free ligand. LFX, [Co(LFX)(H 2O) 4]·Cl 2 and [Zn(LFX)(H 2O) 4]·Cl 2 were found to be very active with IC50 values 14, 11.2 and 43.1, respectively. While, other complexes had

  6. Syntheses, structures, and magnetic properties of acetato- and diphenolato-bridged 3d-4f binuclear complexes [M(3-MeOsaltn)(MeOH)x(ac)Ln(hfac)2] (M = Zn(II), Cu(II), Ni(II), Co(II); Ln = La(III), Gd(III), Tb(III), Dy(III); 3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato; ac = acetato; hfac = hexafluoroacetylacetonato; x = 0 or 1).

    PubMed

    Towatari, Masaaki; Nishi, Koshiro; Fujinami, Takeshi; Matsumoto, Naohide; Sunatsuki, Yukinari; Kojima, Masaaki; Mochida, Naotaka; Ishida, Takayuki; Re, Nazzareno; Mrozinski, Jerzy

    2013-05-20

    A series of 3d-4f binuclear complexes, [M(3-MeOsaltn)(MeOH)x(ac)Ln(hfac)2] (x = 0 for M = Cu(II), Zn(II); x = 1 for M = Co(II), Ni(II); Ln = Gd(III), Tb(III), Dy(III), La(III)), have been synthesized and characterized, where 3-MeOsaltn, ac, and hfac denote N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato, acetato, and hexafluoroacetylacetonato, respectively. The X-ray analyses demonstrated that all the complexes have an acetato- and diphenolato-bridged M(II)-Ln(III) binuclear structure. The Cu(II)-Ln(III) and Zn(II)-Ln(III) complexes are crystallized in an isomorphous triclinic space group P1, where the Cu(II) or Zn(II) ion has square pyramidal coordination geometry with N2O2 donor atoms of 3-MeOsaltn at the equatorial coordination sites and one oxygen atom of the bridging acetato ion at the axial site. The Co(II)-Ln(III) and Ni(II)-Ln(III) complexes are crystallized in an isomorphous monoclinic space group P2(1)/c, where the Co(II) or Ni(II) ion at the high-spin state has an octahedral coordination environment with N2O2 donor atoms of 3-MeOsaltn at the equatorial sites, and one oxygen atom of the bridged acetato and a methanol oxygen atom at the two axial sites. Each Ln(III) ion for all the complexes is coordinated by four oxygen atoms of two phenolato and two methoxy oxygen atoms of "ligand-complex" M(3-MeOsaltn), four oxygen atoms of two hfac(-), and one oxygen atom of the bridging acetato ion; thus, the coordination number is nine. The temperature dependent magnetic susceptibilities from 1.9 to 300 K and the field-dependent magnetization up to 5 T at 1.9 K were measured. Due to the important orbital contributions of the Ln(III) (Tb(III), Dy(III)) and to a lesser extent the M(II) (Ni(II), Co(II)) components, the magnetic interaction between M(II) and Ln(III) ions were investigated by an empirical approach based on a comparison of the magnetic properties of the M(II)-Ln(III), Zn(II)-Ln(III), and M(II)-La(III) complexes. The differences of χ(M)T and M

  7. Ten metal complexes of vitamin B3/niacin: Spectroscopic, thermal, antibacterial, antifungal, cytotoxicity and antitumor studies of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cd(II), Pt(IV) and Au(III) complexes

    NASA Astrophysics Data System (ADS)

    Al-Saif, Foziah A.; Refat, Moamen S.

    2012-08-01

    Ten coordination compounds, namely Mn(NA)2Cl2·4H2O (1), Fe(NA)Cl3(H2O)2 (2), Co(NA)2(NO3)2·6H2O (3), Ni(NA)Cl2·5H2O (4), Cu(NA)Cl2·3H2O (5), Zn(NA)(NO3)2·H2O (6), Pd(NA)2Cl2·H2O (7), Cd(NA)Cl2·H2O (8), Pt(NA)2Cl4·5H2O (9) and Au(NA)Cl3 (10) were obtained by the reactions of the corresponding transition metal salts with vitamin B3/niacin (NA) in the presence of 1:4 (v:v) distilled water: methanol solvent at 70 °C for about 30 min, and their suggested structures were determined by elemental analyses, molar conductivity, (infrared, UV-vis) spectra, effective magnetic moment in Bohr magnetons, electron spin resonance (ESR), thermal analysis (TG), X-ray powder diffraction (XRD) as well as scanning electron microscopy (SEM). The results revealed that in complexes 1, 3, 7, and 9 both of two NA ligand coordinates one metal ion to form four or six coordinated structures, while in compound 10, one NA ligand coordinate to Au+++ ion to form a square-planar geometry with N-bonded pyridine ligand is suggested, and (2, 4, 5, 6 and, 8) complexes have 1:1 structures. Antimicrobial and antitumor activities were assessment against some kind of (G+ and G-) bacteria, fungi and breast carcinoma cells (MCF-7-cell line).

  8. Ternary complexes metal [Co(II), Ni(II), Cu(II) and Zn(II)]--ortho-iodohippurate (I-hip)--acyclovir. X-ray characterization of isostructural [(Co, Ni or Zn)(I-hip)(2)(ACV)(H(2)O)(3)] with stacking as a recognition factor.

    PubMed

    Barceló-Oliver, M; Terrón, A; García-Raso, A; Fiol, J J; Molins, E; Miravitlles, C

    2004-11-01

    Four ternary metal--ortho-iodohippurate (I-hip)--acyclovir (ACV) complexes, [M(I-hip)(2)(ACV)(H(2)O)(3)] where M is Co(II) (1), Ni(II) (2), Cu (3) and Zn(II) have been obtained by reaction between the corresponding binary complexes M(II)(I-hip)(2)xnH(2)O and ACV. Three ternary complexes (M=Co, Ni and Zn) and the corresponding Zn(II)--ortho-iodohippurate binary derivative have been structurally characterized by X-ray diffraction: The studies show these three ternary complexes are isostructural and present, in solid state, an interesting stacking between the nucleobase and the aryl ring of the hippurate moiety, which probably promotes the formation of ternary complexes. Moreover, the two different ligands interact between them by means of ancillary hydrogen bonds with water molecules coordinated to the metal ion. It must be mentioned that these two recognition factors, hydrogen bonds plus stacking, could explain the reason for the isostructurality of these ternary derivatives with so different three metal ions, with diverses trends in coordination numbers and geometries. In solid state, there are two enantiomeric molecules that are related by an inversion center as the crystal-building unit (as a translational motif) for the ternary complexes.

  9. [Coordination compounds of Pd(II) with potential antitumor activity].

    PubMed

    González Vílchez, F; García Basallote, M; Benítez Ordóñez, J; Vilaplana Serrano, R

    1982-01-01

    The first results about the anti-neoplastic activity of Pd(II) ion coordinative compounds with complexones of the ethylenediamine-tetraacetic acid type are described. The assays employing Ehrlich ascites cancer of the mouse show that the presence of substitutes in the ethylenediamine skeleton originates important changes of the activity of such compounds.

  10. Recovery of EDTA from complex solution using Cu(II) as precipitant and Cu(II) subsequent removal by electrolysis.

    PubMed

    Gyliene, O; Aikaite, J; Nivinskiene, O

    2004-12-10

    Ethylendiaminetetraacetate (EDTA) is a chelating agent widely used in industry and agriculture. Resistant to chemical and biological degradation EDTA represents a serious ecological problem. In order to avoid the outlet into the environment a new method of EDTA recycling has been proposed. The method involves substituting of the metal ions in EDTA complexes by Cu(II) and formation of an insoluble Cu2EDTA.4H2O compound at the excess of Cu(II) ions in weakly acidic solutions. Cu(II) ions substitute such metal ions as Ni(II), Zn(II), Co(II), Cd(II), Ca(II) and Mg(II). After treatment of the precipitate with water only, acidic or alkaline solutions the copper from the suspension formed can be removed by electrolysis. The highest current efficiency under galvanostatic conditions is in alkaline solutions, however, the highest yield of EDTA recovery is in acidic solutions. FT-IR investigations and chemical analysis of the precipitate formed have shown that in acidic and in alkaline solutions, H4EDTA and Na2H2EDTA.2H2O were formed, respectively. Electrolysis in acidic solutions gives the best results, i.e. the formed H4EDTA contains the highest amount of EDTA (95%) and the lowest amount of copper (0.01%).

  11. Kinetic fluorescence quenching of CdS quantum dots in the presence of Cu(II): chemometrics-assisted resolving of the kinetic data and quantitative analysis of Cu(II).

    PubMed

    Abdollahi, Hamid; Shamsipur, Mojtaba; Barati, Ali

    2014-06-05

    In this work, the kinetic fluorescence behavior of CdS quantum dots (QDs) in the presence of Cu(II) was investigated. In contrast to some other transition metal ions such as Ag(I), Ni(II), and Hg(II), a gradual red-shift in the emission spectrum of CdS QDs was observed for Cu(II) during the reaction course. More investigations revealed the existence of two chemical components in the recorded kinetic data in the presence of Cu(II). Multivariate curve resolution-alternating least squares (MCR-ALS) method was applied in order to extract pure emission spectra and time-dependent profiles of these two components at different concentrations of Cu(II). The results obtained from resolving the data by MCR-ALS got some information about the mechanism of the interaction between CdS QDs and Cu(II) ions which were in good agreement with those reported in the literature. Moreover, the multivariate method of analysis, partial least-squares (PLS) method, was used to develop a multivariate calibration model for quantitative analysis of Cu(II) using the entire kinetic data sets. The calibration and validation sets were created ranging from 0.02 to 1μM of Cu(II) and were successfully calibrated and predicted by the PLS model. This method allowed a sensitive determination of Cu(II) ions with a detection limit of 13nM based on three times of the standard deviation corresponding to PLS regression.

  12. Calix[4]arene based chemosensor for selective complexation of Cd(II) and Cu(II)

    NASA Astrophysics Data System (ADS)

    Qazi, Mansoor Ahmed; Qureshi, Imdadullah; Memon, Shahabuddin

    2010-06-01

    The present article describes synthesis, characterization and a detailed complexation study of calix[4]arene based chemosensor ( 4) bearing two anthracenyl units as signaling groups on its coordination sphere. The complex formation ability of 4 toward selected transition metals such as Cd(II), Co(II), Cu(II), Ni(II) and Pb(II) has been investigated by UV-visible spectroscopy. Assessment of results reveal that the chemosensor is selective toward Cd(II) and Cu(II). The FT-IR spectroscopic method was applied for further confirmation of the complexation phenomenon. Besides this, a study regarding interference of other metals on complex formation in solution has also supported the efficient binding preference of 4 for Cd(II) and Cu(II). From the results it has been concluded that 4 has compatible coordination sphere to accommodate these metals. The similarities and differences revealed that being soft nature of both metals and because of diagonal relationship in the periodic table their coordination behavior toward N/O-donor ligand may be treated as a test on possibility of the Cu(II) ions to be displaced by Cd(II). The study certainly will help in understanding the hazards of Cd(II) in biological systems.

  13. Tren centered tris-macrocycles as polytopic ligands for Cu(II) and Ni(II).

    PubMed

    Siegfried, Liselotte; McMahon, C Niamh; Kaden, Thomas A; Palivan, Cornelia; Gescheidt, Georg

    2004-07-21

    Two novel symmetric polytopic ligands L(1) and L(2) have been synthesized. They are composed of three 1,4,8,11-tetraazacyclotetradecane macrocycles which are connected to a central tren moiety via an ethylene and a trimethylene bridge, respectively. The complexation potential and the speciation diagrams of L(1) and L(2) towards Cu(2+) and Ni(2+) were determined by spectrophotometric and potentiometric titrations. Insight into the geometry of the Cu(2+) complexes is provided by UV-VIS and EPR spectroscopy. The simplified ligands L(3) and L(4) are utilized as references for an aminoethyl- and a tren-substituted tetraaza macrocycle to help assign the EPR spectra of the polytopic ligands L(1) and L(2). At a metal-to-ligand ratio of 3 : 1, the metal cations are preferentially bound to the tetraaza macrocycles of L(1) and L(2) in a square planar geometry. At high pH values, a nitrogen atom of the tren moiety in L(1) serves as an additional ligand in an axial position leading to a square pyramidal coordination around Cu(2+), whereas in L(2) no such geometry change is observed. At a metal-to-ligand ratio of 4 : 1, the additional metal cation resides in the central tren moiety of L(1) and L(2). However, in contrast to the typical trigonal bipyramidal geometry found in the [Cutren](2+) complex, the fourth Cu(2+) has a square pyramidal coordination caused by the interaction with the Cu(2+) cations in the macrocycles (as evidenced by EPR spectra). Since the sequence of metal complexation is such that the first three metal ions always bind to the three macrocycles of L(1) and L(2) and the fourth to the tren unit, it is possible to prepare heteronuclear complexes such as [Cu(3)NiL](8+) or [Ni(3)CuL](8+), which can be unambiguously identified by their spectral properties.

  14. DFT investigation of Ni(II) adsorption onto MA-DTPA/PVDF chelating membrane in the presence of coexistent cations and organic acids.

    PubMed

    Song, Laizhou; Zhao, Xiaodan; Fu, Jie; Wang, Xiuli; Sheng, Yiping; Liu, Xiaowei

    2012-01-15

    Melamine-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (MA-DTPA/PVDF) chelating membrane bearing polyaminecarboxylate groups was used to remove Ni(II) from nickel plating effluents. Adsorption experiments were conducted to study the adsorption of the membrane towards Ni(II) in Ni(II)-Ca(II), Ni(II)-NH(4)(+), Ni(II)-Fe(III) binary systems, and Ni(II)-lactic acid, Ni(II)-succinic acid and Ni(II)-citric acid complex systems. For the ternary nickel plating processes, the effects of 3d transition metals including Fe(II), Co(II), Cu(II) and Zn(II) on Ni(II) adsorption were evaluated. The influences of the aforementioned coexistent cations and organic acids were elucidated by the continuum solvation model (COSMO)-corrected density functional theory (DFT) method. Geometries and complexation energies were analyzed for metal-MA-DTPA and Ni(II)-organic acid complexes. DFT results accord with the experimental data, indicating that DFT is helpful to evaluate the complexation between the membrane and metal cations. The coexistent Ca(II) tends to form more stable complex with MA-DTPA ligand than NH(4)(+) and Fe(III), and can interfere with the formation of Ni(II)-MA-DTPA complex. The complexing sequence of 3d metals with MA-DTPA ligand is Zn(II)Cu(II) have the considerable competition with Ni(II). The stabilities of Ni(II)-organic acid complexes follow the order of lactic acid

  15. Selective recovery of Pd(II) from extremely acidic solution using ion-imprinted chitosan fiber: Adsorption performance and mechanisms.

    PubMed

    Lin, Shuo; Wei, Wei; Wu, Xiaohui; Zhou, Tao; Mao, Juan; Yun, Yeoung-Sang

    2015-12-15

    A novel, selective and acid-resisting chitosan fiber adsorbent was prepared by the ion-imprinting technique using Pd(II) and epichlorohydrin as the template and two-step crosslinking agent, respectively. The resulting ion-imprinted chitosan fibers (IIF) were used to selectively adsorb Pd(II) under extremely acidic synthetic metal solutions. The adsorption and selectivity performances of IIF including kinetics, isotherms, pH effects, and regeneration were investigated. Pd(II) rapidly adsorbed on the IIF within 100 min, achieving the adsorption equilibrium. The isotherm results showed that the maximum Pd(II) uptake on the IIF was maintained as 324.6-326.4 mg g(-1) in solutions containing single and multiple metals, whereas the Pd(II) uptake on non-imprinted fibers (NIF) decreased from 313.7 to 235.3 mg g(-1) in solution containing multiple metals. Higher selectivity coefficients values were obtained from the adsorption on the IIF, indicating a better Pd(II) selectivity. The amine group, supposedly the predominant adsorption site for Pd(II), was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The pH value played a significant role on the mechanism of the selective adsorption in the extremely acidic conditions. Furthermore, the stabilized performance for three cycles of sorption/desorption shows a potential for further large-scale applications.

  16. Recovery of Pd(II) from hydrochloric solution using polyallylamine hydrochloride-modified Escherichia coli biomass.

    PubMed

    Park, Jiyeong; Won, Sung Wook; Mao, Juan; Kwak, In Seob; Yun, Yeoung-Sang

    2010-09-15

    A new type of biosorbent able to bind anionic metals was developed by cross-linking of waste biomass Escherichia coli with polyallylamine hydrochloride (PAH). The PAH-modified biomass was investigated for the removal and recovery of Pd(II), in the chloro-complex form, from aqueous solution. The performance of the PAH-modified biomass was evaluated in terms of the following parameters: the solution pH, contact time and initial metal concentration. In the pH edge experiments, the uptake of Pd(II) increased with increasing pH. Pd(II) biosorption proceeded rapidly in the first 10 min, with almost complete equilibrium being achieved within 60 min. Moreover, the isotherm data showed that the maximum uptakes of Pd(II) were 265.3mg/g at pH 3 and 212.9 mg/g at pH 2, respectively. After incineration of the Pd-loaded PAH-modified biomass, metallic palladium was recovered in the ash. X-ray photoelectron spectroscopy (XPS) results confirmed that the palladium was recovered in two valency states: zero-valent and divalent palladium (as PdO). Therefore, we concluded that PAH-modified biomass is a useful and cost-effective biosorbent for the recovery of anionic precious metals as chloro-complex solutions containing hydrochloric acid produced from metal refining processes.

  17. Ion-imprinted modified chitosan resin for selective removal of Pd(II) ions.

    PubMed

    Monier, M; Abdel-Latif, D A; Abou El-Reash, Y G

    2016-05-01

    In this work, a selective Pd(II) ions chelating resin based on 2-aminobenzaldehyde modified chitosan Schiff's base (Pd-CAZ) was synthesized through ion-imprinting technique. All the performed chemical and morphological changes during the modification and Pd(II) ion-imprinting process were investigated using instrumental techniques including FTIR, (1)H NMR, XRD and SEM. In addition, the mechanism of Pd(II) binding to the synthesized polymeric active sites was elucidated using both XPS and FTIR spectra, and the results indicated that Pd(II) ions coordinated in square planar geometry. Also, the selective extraction experiments with respect to Pd-CAZ and control non-imprinted NI-CAZ resins were performed to obtain the fundamental thermodynamic, kinetic and isotherm parameters. In all cases the adsorption was endothermic, spontaneous, fit well with pseudo-second order kinetic model and Langmuir adsorption isotherm model with maximum adsorption capacities of 275±0.4 and 114±0.2 mg/g for Pd-CAZ and NI-CAZ, respectively. Moreover, the regeneration and recovery experiments indicated that the resin maintain about 96% of its original activity after the fifth adsorption-desorption cycle, revealing the high economic value.

  18. Surface complexation of heavy metal cations on clay edges: insights from first principles molecular dynamics simulation of Ni(II)

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Liu, Xiandong; Lu, Xiancai; He, Mengjia; Jan Meijer, Evert; Wang, Rucheng

    2017-04-01

    Aiming at an atomistic mechanism of heavy metal cation complexing on clay surfaces, we carried out systematic first principles molecular dynamics (FPMD) simulations to investigate the structures, free energies and acidity constants of Ni(II) complexes formed on edge surfaces of 2:1 phyllosilicates. Three representative complexes were studied, including monodentate complex on the tbnd SiO site, bidentate complex on the tbnd Al(OH)2 site, and tetradentate complex on the octahedral vacancy where Ni(II) fits well into the lattice. The complexes structures were characterized in detail. Computed free energy values indicate that the tetradentate complex is significantly more stable than the other two. The calculated acidity constants indicate that the tetradentate complex can get deprotonated (pKa = 8.4) at the ambient conditions whereas the other two hardly deprotonate due to extremely high pKa values. By comparing with the 2 Site Protolysis Non Electrostatic Surface Complexation and Cation Exchange (2SPNE SC/CE) model, the vacant site has been assigned to the strong site and the other two to the weak site, respectively. Thus a link has been built between atomistic simulations and macroscopic experiments and it is deduced that this should also apply to other heavy metal cations based on additional simulations of Co(II) and Cu(II) and previous simulations of Fe(II) and Cd(II)). This study forms a physical basis for understanding the transport and fixation of heavy metal elements in many geologic environments.

  19. Synthesis and structural characterization of Pd(II) complexes derived from perimidine ligand and their in vitro antimicrobial studies

    NASA Astrophysics Data System (ADS)

    Azam, Mohammad; Warad, Ismail; Al-Resayes, Saud I.; Alzaqri, Nabil; Khan, Mohammad Rizwan; Pallepogu, Raghavaiah; Dwivedi, Sourabh; Musarrat, Javed; Shakir, Mohammad

    2013-09-01

    A novel series of Pd(II) complexes derived from 2-thiophenecarboxaldehyde and 1,8-diaminonaphthalene has been synthesized and characterized by various physico-chemical and spectroscopic techniques viz., elemental analyses, IR, UV-vis, 1H and 13C NMR spectroscopy, and ESI-mass spectrometry. The structure of ligand, 2-(2-thienyl)-2,3-dihydro-1H-perimidine has been ascertained on the basis of single crystal X-ray diffraction. All Pd(II) complexes together with the corresponding ligand have been evaluated for their ability to suppress the in vitro growth of microbes, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Citrobacter sp., Bacillus subtilis and Stenotrophomonas acidaminiphila and results show that Pd(II) complexes have more significant antimicrobial activity than their corresponding ligand. Fluorescence spectroscopic measurements clearly support that both of the Pd(II) complexes show significant DNA binding with calf thymus DNA.

  20. Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Fu, Ruiqi; Sun, Yue; Zhou, Xiaoxin; Baig, Shams Ali; Xu, Xinhua

    2016-04-01

    In this study, EDTA-functionalized Fe3O4 (Fe3O4@SiO2-EDTA) was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups for Pb(II) and Cu(II) removal from aqueous solutions. Fe3O4@SiO2-EDTA composites were characterized using SEM, TEM, EDX, FTIR, XPS, TGA and saturated magnetization techniques. Maximum Pb(II) adsorption capacity was found to be 114.94 mg g-1 with SiO2/EDTA molar ratio of 2.5:1. The adsorption rate was significantly fast and the equilibrium was reached within 10 min. The optimum pH was recorded to be 5.0. The maximum adsorption capacity of the studied heavy metal ions calculated by Langmuir model followed the order: Cu(II) (0.58 mmol g-1) > Pb(II) (0.55 mmol g-1) ≈ Ni(II) (0.55 mmol g-1) > Cd(II) (0.45 mmol g-1). Moreover, Pb(II) and Cu(II) adsorption capacities were not significantly affected by co-existing cations and NOM. These results suggested that this adsorbent can be considered as a promising adsorbent to remove Pb(II) and Cu(II) from wastewaters.

  1. Ni(II) and Pd(II) complexes with new N,O donor thiophene appended Schiff base ligand: Synthesis, electrochemistry, X-ray structure and DFT calculation

    NASA Astrophysics Data System (ADS)

    Kundu, Subhankar; Pramanik, Ajoy Kumar; Mondal, Apurba Sau; Mondal, Tapan Kumar

    2016-07-01

    The thiophene appended Schiff's base ligand, 1-(2-(thiophen-2-yl)ethylimino)methyl)naphthalene-2-ol (HL) with N,O donor sites has been synthesized by the condensation between 2-hydroxy-1-naphthaldehyde and thiophene-2-ethylamine. The square planar 1:2 complexes of HL having general formula [M(L)2] (M = Ni(1) and Pd(2)) with nickel(II) and palladium(II) have been synthesized and characterized by several spectroscopic techniques. The geometry has been confirmed by single crystal X-ray study for complex 1. The electronic structure and spectral properties of the complexes are interpreted by DFT and TDDFT studies.

  2. Determination of Pd(II) content in catalysts and tap water samples via photoacoustic spectroscopy analysis of Pd(II)-3-[2'-thiazolylazo]-2,6-diaminopyridine complex on solid phase.

    PubMed

    Saavedra, Renato; Soto, César; Yañez, Jorge; Toral, Mara Ines

    2009-08-15

    In this work a simple method for the determination of Pd(II) by photoacoustic spectroscopy (PAS) is introduced. The method is based on Pd(II) colorimetric reaction with immobilized 3-[2(')-thiazolylazo]-2,6 diaminopyridine (2,6 TADAP) retained in a cationic resin Dowex 50W X4 20/50. The immobilization of Pd(II) on solid phase is combined with PAS. The Pd(II) concentration was determined by conventional photoacoustic measurement in the range of 625-645 nm. The calibration for Pd(II) was linear over the range 12-210 microg L(-1). The obtained analytical features were LOD 4 microg L(-1) and LOQ 12 microg L(-1). The relative standard deviation of the method was <5%. The proposed method has been successfully tested in determination of leachable Pd in disposed catalyst and in spiked samples of tap water. In the introduced method, complicated preparatory steps became simple, inexpensive, and it is suitable for applications in environmental samples. Results obtained by PAS agree with those obtained by using conventional FAAS. The figures of merit in this method make it an attractive alternative to UV-vis and FAAS.

  3. Cu(II) promotes amyloid pore formation

    SciTech Connect

    Zhang, Hangyu; Rochet, Jean-Christophe; Stanciu, Lia A.

    2015-08-14

    The aggregation of α-synuclein is associated with dopamine neuron death in Parkinson's disease. There is controversy in the field over the question of which species of the aggregates, fibrils or protofibrils, are toxic. Moreover, compelling evidence suggested the exposure to heavy metals to be a risk of PD. Nevertheless, the mechanism of metal ions in promoting PD remains unclear. In this research, we investigated the structural basis of Cu(II) induced aggregation of α-synuclein. Using transmission electron microscopy experiments, Cu(II) was found to promote in vitro aggregation of α-synuclein by facilitating annular protofibril formation rather than fibril formation. Furthermore, neuroprotective baicalein disaggregated annular protofibrils accompanied by considerable decrease of β-sheet content. These results strongly support the hypothesis that annular protofibrils are the toxic species, rather than fibrils, thereby inspiring us to search novel therapeutic strategies for the suppression of the toxic annular protofibril formation. - Highlights: • Cu(II) promoted the annular protofibril formation of α-synuclein in vitro. • Cu(II) postponed the in vitro fibrillization of α-synuclein. • Neuroprotective baicalein disaggregated annular protofibrils.

  4. Formation of very stable and selective Cu(II) complexes with a non-macrocyclic ligand: can basicity rival pre-organization?

    PubMed

    Abada, Sabah; Lecointre, Alexandre; Elhabiri, Mourad; Charbonnière, Loïc J

    2010-10-14

    The synthesis of ligand L based on a 2,6-bis[(N,N-bis(methylene phosphonic acid)aminomethyl] pyridine scaffold is described. Potentiometry combined with UV-Vis absorption spectrophotometric titrations were used to determine the protonation constants of the ligand and the stability constants of its corresponding Cu(II), Ni(II), Zn(II) and Ga(III) cations (0.1 M NaClO(4), 25.0 °C). The physico-chemical approach revealed very large stability constants for Cu(II) complexation (logK(CuL) = 22.71(7)) reflected in a very high pCu(II) value of ∼ 15.5 (pH = 7.4, [L](tot) = 10(-5) M, [Cu](tot) = 10(-6) M), close to those measured for the strong methylphosphonate functionalized cyclen chelators. Based on a literature survey, a correlation is proposed between the pK values of branched polyamine ligands and their stability constants for Cu(II) complexation, allowing for an estimation of the latter on the basis of the protonation constants of L. Ligand L was also shown to be very selective towards Cu(II) compared to the other cations studied (ΔlogK > 4). UV-Vis spectroscopy and kinetic measurements indicated that the formation of the cupric complexes with L is very fast, which, in combination with all other properties, makes it an excellent non-cyclic target for Cu(II) radiopharmaceutical within the frame of (64)Cu positron emission tomography imaging and radiotherapy.

  5. Synthesis, spectral, and thermal characterizations of Ni(II) and Cu(II) β-diketone complexes with thenoyltrifluoroacetone ligand

    NASA Astrophysics Data System (ADS)

    Chen, Zhimin; Wu, Yiqun; Huang, Fuxin; Gu, Donghong; Gan, Fuxi

    2007-04-01

    Two kinds of nickel(II) and copper(II) β-diketone complexes derived from thenoyltrifluoroacetone ligand with blue-violet light absorption were synthesized by reacting free ligand and different metal(II) ions in sodium methoxide solution. Their structures were postulated based on elemental analysis, ESI-MS, FT-IR spectra and UV-vis electronic absorption spectra. Smooth films on K9 glass substrates were prepared using the spin-coating method. Their solubility in organic solvents, absorption properties of thin film and thermal stability of these complexes were evaluated.

  6. Synthesis, spectral, and thermal characterizations of Ni(II) and Cu(II) beta-diketone complexes with thenoyltrifluoroacetone ligand.

    PubMed

    Chen, Zhimin; Wu, Yiqun; Huang, Fuxin; Gu, Donghong; Gan, Fuxi

    2007-04-01

    Two kinds of nickel(II) and copper(II) beta-diketone complexes derived from thenoyltrifluoroacetone ligand with blue-violet light absorption were synthesized by reacting free ligand and different metal(II) ions in sodium methoxide solution. Their structures were postulated based on elemental analysis, ESI-MS, FT-IR spectra and UV-vis electronic absorption spectra. Smooth films on K9 glass substrates were prepared using the spin-coating method. Their solubility in organic solvents, absorption properties of thin film and thermal stability of these complexes were evaluated.

  7. Microwave assisted synthesis of biarlys by Csbnd C coupling reactions with a new chitosan supported Pd(II) catalyst

    NASA Astrophysics Data System (ADS)

    Baran, Talat; Menteş, Ayfer

    2016-10-01

    In this study a new type chitosan-based support has been produced for Pd(II) catalyst and its catalytic performance in Suzuki Csbnd C reactions has been studied under microwave irradiation without using any solvent. The chemical identification of the catalyst was performed using TG/DTG, FTIR, UV-Vis ICP-OES, SEM/EDAX, 13C NMR, molar conductivity, XRD and magnetic moment techniques. The performance of this new Pd(II) catalyst was studied in Suzuki Csbnd C reactions. The Pd(II) catalyst exhibited a good catalytic performance in very short time (4 min) by giving high TONs and TOFs with low amount of the catalyst (0.015 mol%). The catalyst also had reusability and did not lose its activity until six runs.

  8. 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.

    PubMed

    Al-Shaalan, Nora H

    2011-10-13

    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), UO(2) (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 UO(2) (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 UO(2) (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.

  9. DNA Oxidative Cleavage Induced by the Novel Peptide Derivatives of 3-(quinoxalin-6-yl)alanine in Combination with Cu(II) or Fe(II) Ions

    PubMed Central

    Szczepanik, Wojciech; Kucharczyk-Klamińska, Marzena; Stefanowicz, Piotr; Staszewska, Anna; Szewczuk, Zbigniew; Skała, Jacek; Mysiak, Andrzej; Jeżowska-Bojczuk, Małgorzata

    2009-01-01

    Three model dipeptides containing 3-(2,3-di(pyridin-2-yl)quinoxalin-6-yl)alanine, 3-(dipyrido[3,2-a:2,3-c]phenazin-11-yl)alanine, and 3-(2,3-diphenylquinoxalin-6-yl)alanine were studied with respect to their ability to bind selected transition metal ions, such as Cu(II), Fe(II), Ni(II), Co(II), Mn(II), and Cr(III). It was found that only Cu(II) and Fe(II) ions could form stable complex species with the studied compounds. The ability to form the complexes correlated well with DNA damage experiments. Only the ferrous and cupric complexes are capable of generating both single- and double-strand scissions. However, double-strand breakages appear to be dominating lesions in the presence of hydrogen peroxide, especially for copper(II) containing systems. The quantity of breakage products in the presence of N-(3-(dipyrido[3,2-a:2,3-c]phenazine-11-yl)alanyl)glycine complexes was the highest as compared to the complexes of the remaining compounds. Moreover, this ligand was the only one that cleaved DNA in the absence of either Cu(II) or Fe(II) ions. PMID:20224817

  10. The use of a polymer inclusion membrane in a paper-based sensor for the selective determination of Cu(II).

    PubMed

    Jayawardane, B Manori; Coo, Lilibeth dlC; Cattrall, Robert W; Kolev, Spas D

    2013-11-25

    A disposable paper-based sensor (PBS) is described for the determination of Cu(II) in natural and waste waters at approximately 2 cents per measurement. The device makes use of a polymer inclusion membrane (PIM) to provide the selectivity for Cu(II). The PIM consists of 40 wt% di(2-ethlyhexyl) phosphoric acid (D2EHPA) as the carrier, 10 wt% dioctyl phthalate (DOP) as a plasticizer, 49.5 wt% poly(vinyl chloride) (PVC) as the base polymer and 0.5 wt% (mm(-1)) 1-(2'-pyridylazo)-2-naphthol (PAN) as the colourimetric reagent. High selectivity under mildly acidic conditions (HCl, pH 2.0) is achieved for Cu(II) in the presence of frequently encountered metal ions in natural and waste waters such as Fe(III), Al(III), Zn(II), Cd(II), Pb(II), Ca(II), Mg(II), and Ni(II). The laminated PBS consists of a PIM sensing disc (2mm in diameter) attached to the centre of a circular hydrophilic zone (7 mm in diameter) pretreated with 0.01 M HCl. This hydrophilic zone separates the sample port (a circular hole in the plastic cover) from the PIM sensing disc. After introducing 19.2 μL of a sample/standard solution to the sample port, Cu(II) diffuses across the hydrophilic zone and is extracted into the PIM disc as the Cu(II)-D2EHPA complex which subsequently reacts with PAN to produce the red-purple coloured Cu(II)-PAN complex. The colour intensity of the PIM disc is measured 15 min after sample/standard introduction by scanning using a flatbed scanner. Under optimal conditions the device is characterized by a limit of detection (LOD) and limit of quantitation (LOQ) of 0.06 and 0.21 mg L(-1) Cu(II), respectively, with two linear ranges together covering the Cu(II) concentration range from 0.1 to 30.0 mg L(-1). The PBS was successfully applied to the determination of Cu(II) in hot tap water and mine tailings water.

  11. Nanostructured discotic Pd(ii) metallomesogens as one-dimensional proton conductors.

    PubMed

    Cuerva, Cristián; Campo, José A; Cano, Mercedes; Schmidt, Rainer

    2016-12-20

    A novel family of square-planar Pd(ii) complexes based on isoquinoline-functionalised pyrazolate ligands [Pd(pz(R(n,n)iq))2] (R(n,n) = C6H3(OCnH2n+1)2, n = 4, 6, 8, 10, 12, 14, 16, 18) has been synthesised and characterised. The new complexes show mesomorphic properties and exhibit columnar mesophases that are highly-stable in exceptionally wide temperature ranges of up to 345 °C. The formation of nanochannels in the fluid liquid crystal phases generates continuous pathways for one-dimensional proton conduction on the basis of C-HN proton transfer. The complex with an intermediate chain length (n = 12) shows the highest proton conductivity of 1.34 × 10(-4) S m(-1) at 269 °C in the hexagonal columnar mesophase, and an activation energy of 0.84 eV. The influence of both the terminal alkyl chain length and the mesophase columnar organisation on the proton conduction mechanism is demonstrated. The series of Pd(ii) complexes investigated in this work constitutes one of the first examples of proton-conducting metallomesogens with potential applications in PEM fuel cells.

  12. Synthesis, Characterization, and Antibacterial Studies of Pd(II) and Pt(II) Complexes of Some Diaminopyrimidine Derivatives

    PubMed Central

    Ajibade, Peter A.; Idemudia, Omoruyi G.

    2013-01-01

    Pd(II) and Pt(II) complexes of trimethoprim and pyrimethamine were synthesized and characterized by elemental analysis, UV-Vis, FTIR, and NMR spectroscopy. The complexes are formulated as four coordinate square planar species containing two molecules of the drugs and two chloride or thiocyanate ions. The coordination of the metal ions to the pyrimidine nitrogen atom of the drugs was confirmed by spectroscopic analyses. The complexes were screened for their antibacterial activities against eight bacterial isolates. They showed varied activities with the active metal complexes showing more enhanced inhibition than either trimethoprim or pyrimethamine. The Pd(II) complexes of pyrimethamine showed unique inhibitory activities against P. aeruginosa and B. pumilus, and none of the other complexes or the drugs showed any activity against these bacteria isolates. The MIC and MBC determinations revealed that these Pd(II) complexes are the most active. Structure activity relationship showed that Pt(II) complexes containing chloride ions are more active, while for Pd(II) complexes containing thiocyanate ions showed more enhanced activity than those containing chloride ions. PMID:23573071

  13. Quantitative study of Au(III) and Pd(II) ion biosorption on genetically engineered Tobacco mosaic virus.

    PubMed

    Lim, Jung-Sun; Kim, Seung-Min; Lee, Sang-Yup; Stach, Eric A; Culver, James N; Harris, Michael T

    2010-02-15

    One major obstacle in the mineralization of metal onto biologically derived templates is the lack of fundamental information pertaining to the relationship between metal ion loading and overall metal deposition onto the biotemplate. This study focuses on Au(III) and Pd(II) biosorption on the genetically-modified model biological template Tobacco mosaic virus (TMV1Cys). Metal ion (Au(III) or Pd(II)) loading on the TMV1Cys template was measured as a function of the equilibrium concentration of Au(III) or Pd(II) ions in solution at several temperatures. In addition, the Pd(II) loading on the TMV-wild (wild-type TMV) and TMV1Cys were compared to estimate the improvement of metal ion loading by genetic modification of the biotemplate. The gold or palladium coatings on the TMV1Cys were prepared using various metal ion loadings. Results show, for a range of metal ion loadings, a positive correlation existed between the concentration of the metal ions and the coating density of the metals deposited on the virus surface.

  14. Antibacterial activity of Pd(II) complexes with salicylaldehyde-amino acids Schiff bases ligands.

    PubMed

    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.

  15. Extraction of Pd(II), Rh(III) and Ru(III) from HNO(3) aqueous solution to betainium bis(trifluoromethanesulfonyl)imide ionic liquid.

    PubMed

    Sasaki, Kotoe; Takao, Koichiro; Suzuki, Tomoya; Mori, Takahiro; Arai, Tsuyoshi; Ikeda, Yasuhisa

    2014-04-21

    Extraction efficiencies of Pd(ii), Rh(iii), and Ru(iii) from HNO3(aq) to [Hbet][Tf2N] were demonstrated, i.e., Pd(ii) is the most extractable, Rh(iii) is medium extractable, and Ru(iii) is the least extractable. The extraction seems to proceed through coordination of betaine to the metal ions and the cation exchange of the formed complex with H(+).

  16. Binding properties of a new anti-tumor component (2,2'-bipyridin octylglycinato Pd(II) nitrate) with bovine beta-lactoglobulin-A and -B.

    PubMed

    Divsalar, A; Saboury, A A; Mansoori-Torshizi, H; Moosavi-Movahedi, A A

    2007-10-01

    An new water soluble palladium (II) complex of formula [Pd(bpy)(Oct-Gly)]NO(3), (where bpy is 2,2'-bipyridine and Oct-Gly is octylglycine) have been synthesised. The Pd(II) complex has been characterized by elemental analysis and conductivity measurements as well as spectroscopic methods such as infrared, (1)H NMR, and ultraviolet-visible. The interaction between the new Pd(II)-complex (2,2'-bipyridin octylglycinato Pd(II) nitrate), an anti-tumor component, with beta-lactoglobulin-A and -B (BLG-A and -B) was studied by fluorescence spectroscopy and far and near-UV circular dichroism (CD) spectrophotometric techniques. A strong fluorescence quenching interaction of Pd(II) complex with BLG-A and -B was observed. The quenching constant was determined using the modified Stern-Volmer equation. The calculated binding constants of Pd(II) complex with BLG-A and -B were 0.51 and 0.28 (x 10(6) M(-1)) and the corresponding average number of binding sites were 2.8 and 1.5, respectively. Far-UV CD studies showed that the Pd(II) complex can significantly change the secondary structure of BLG-A and -B via an increase in the content of alpha-helix structure, which stabilizes the secondary structure of the proteins. Near-UV CD data clearly indicate the alteration in the tertiary structure of BLG-A and -B due to the interaction with Pd(II) complex. Pd(II) complex can change and stabilize both the secondary and tertiary structures of BLG-A more than BLG-B. These conformational changes may be considered to be a deleterious effect of the designed ligand on the protein structures. The difference in the interaction properties observed for BLG-A and -B with Pd(II) complex is due to the difference in the amino acid sequences between these two variants.

  17. Designing a heterotrinuclear Cu(II)-Ni(II)-Cu(II) complex from a mononuclear Cu(II) Schiff base precursor with dicyanamide as a coligand: synthesis, crystal structure, thermal and photoluminescence properties.

    PubMed

    Hopa, Cigdem; Cokay, Ismail

    2016-08-01

    Schiff bases are considered `versatile ligands' in coordination chemistry. The design of polynuclear complexes has become of interest due to their facile preparations and varied synthetic, structural and magnetic properties. The reaction of the `ligand complex' [CuL] {H2L is 2,2'-[propane-1,3-diylbis(nitrilomethanylylidene)]diphenol} with Ni(OAc)2·4H2O (OAc is acetate) in the presence of dicyanamide (dca) leads to the formation of bis(dicyanamido-1κN(1))bis(dimethyl sulfoxide)-2κO,3κO-bis{μ-2,2'-[propane-1,3-diylbis(nitrilomethanylylidene)]diphenolato}-1:2κ(6)O,O':O,N,N',O';1:3κ(6)O,O':O,N,N',O'-dicopper(II)nickel(II), [Cu2Ni(C17H16N2O2)2(C2N3)2(C2H6OS)2]. The complex shows strong absorption bands in the frequency region 2155-2269 cm(-1), which clearly proves the presence of terminal bonding dca groups. A single-crystal X-ray study revealed that two [CuL] units coordinate to an Ni(II) atom through the phenolate O atoms, with double phenolate bridges between Cu(II) and Ni(II) atoms. Two terminal dca groups complete the distorted octahedral geometry around the central Ni(II) atom. According to differential thermal analysis-thermogravimetric analysis (DTA-TGA), the title complex is stable up to 423 K and thermal decomposition starts with the release of two coordinated dimethyl sulfoxide molecules. Free H2L exhibits photoluminescence properties originating from intraligand (π-π*) transitions and fluorescence quenching is observed on complexation of H2L with Cu(II).

  18. Antiproliferative and apoptotic effects of two new Pd(II) methylsarcosinedithiocarbamate derivatives on human acute myeloid leukemia cells in vitro.

    PubMed

    Aldinucci, Donatella; Cattaruzza, Lara; Lorenzon, Debora; Giovagnini, Lorena; Fregona, Dolores; Colombatti, Alfonso

    2008-01-01

    [Pd(MSDT)Cl]n palladium, chloro[methyl N-(dithiocarboxy-kS,kS')-N-methylglycinate], and [Pd(MSDT) Br]n palladium, bromo[methyl N-(dithiocarboxy-kS,kS')-N-methylglycinate], palladium (Pd)(II) derivatives are two newly synthesized Pd(II) derivatives of methylsarcosinedithiocarbamate (MSDT), containing a sulfur chelating ligand that is able to strongly bind the metal center, so preventing interactions with sulfur-containing enzymes. In fact, these reactions are believed to be responsible for the nephrotoxicity induced by platinum (II)-based drugs. Their activity has been evaluated in a panel of acute myeloid leukemia (AML) cell lines representing different French-American-British (FAB) subtypes and in the Philadelphia (Ph)-positive cell line K-562 and compared to cisplatin. Both compounds suppressed, in a dose-dependent manner, colony formation in methylcellulose with ID50 values comparable to those of the reference drug cisplatin, excluding the ML-3 cell line (ID50 10-fold lower than cisplatin). Exposure of HL-60, ML-3, NB-4, and THP-1 cell lines to a cytotoxic concentration of [Pd(MSDT)Br]n (5 microM) determined: downregulation of the antiapoptotic molecule Bcl-2, upregulation of the proapoptotic molecule Bax; apoptosis induction, as evaluated by APO2.7 and annexin V staining; mitochondrial membrane permeabilization; and DNA fragmentation. In ML-3 cells the Pd(II) complexes were more active than cisplatin in apoptosis induction. Finally, [Pd(MSDT)Br]n showed an inhibitory effect on clonogenic growth of hematopoietic progenitors (CFU-GM, CFU-GEMM, and BFU-E) with both ID50 and ID90 comparable to those of cisplatin. Remarkably, the Pd(II) complex was more potent in inhibiting the clonogenic growth of the less differentiated AML cell lines KG-1a, HL-60, NB-4, ML-3, and THP-1 (ID50 ranging from 0.02 +/- 0.001 to 0.52 +/- 0.04 microM), compared to normal hematopoietic progenitors (ID50 of 2.1 +/- 0.1, 3.8 +/- 0.4, and 2.5 +/- 0.2 microM) for CFU-GEMM, BFU-E, and CFU

  19. Simultaneous determination of Cd(II) and Cu(II) using stripping voltammetry in groundwater, soil and Alhagi maurorum plants in industrial and urban areas in Northern Border, Saudi Arabia with luminol as a chelating agent.

    PubMed

    Al-Hossainy, Ahmed Farouk

    2015-01-01

    The cathodic stripping voltammetry of Cu(II) and Cd(II) speciation was re-optimized by using luminol (Lu) in groundwater, soil and Alhagi maurorum plants, finding differences with the pre-existing method and a different interpretation for the electroactive species. The main findings are that optimum sensitivity is obtained at 0.3-142.5 ng/mL and 0.065-60.0 ng/mL for copper and cadmium, respectively, that the complexes responsible for adsorption on the electrode are CuLu and CdLu, and that the sensitivity of the method is much improved in the absence of dissolved oxygen. The limit of detection of the method was 0.011 ± 0.001 ng/mL for Cu(II) and 0.013 ± 0.001 ng/mL for Cd(II). The interference of some common ions: Cr(III), Fe(III), Zn(II), Ni(II), Co(II) and Mo(II) was studied. It was concluded that application of this method for the determination of Cu(II) and Cd(II) in groundwater, soil and Alhagi maurorum plants led to satisfactory results.

  20. Spectral and thermodynamic properties of Ag(I), Au(III), Cd(II), Co(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II), U(IV), and Zn(II) binding by methanobactin from Methylosinus trichosporium OB3b.

    PubMed

    Choi, Dong W; Do, Young S; Zea, Corbin J; McEllistrem, Marcus T; Lee, Sung-W; Semrau, Jeremy D; Pohl, Nicola L; Kisting, Clint J; Scardino, Lori L; Hartsel, Scott C; Boyd, Eric S; Geesey, Gill G; Riedel, Theran P; Shafe, Peter H; Kranski, Kim A; Tritsch, John R; Antholine, William E; DiSpirito, Alan A

    2006-12-01

    Methanobactin (mb) is a novel chromopeptide that appears to function as the extracellular component of a copper acquisition system in methanotrophic bacteria. To examine this potential physiological role, and to distinguish it from iron binding siderophores, the spectral (UV-visible absorption, circular dichroism, fluorescence, and X-ray photoelectron) and thermodynamic properties of metal binding by mb were examined. In the absence of Cu(II) or Cu(I), mb will bind Ag(I), Au(III), Co(II), Cd(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II), U(VI), or Zn(II), but not Ba(II), Ca(II), La(II), Mg(II), and Sr(II). The results suggest metals such as Ag(I), Au(III), Hg(II), Pb(II) and possibly U(VI) are bound by a mechanism similar to Cu, whereas the coordination of Co(II), Cd(II), Fe(III), Mn(II), Ni(II) and Zn(II) by mb differs from Cu(II). Consistent with its role as a copper-binding compound or chalkophore, the binding constants of all the metals examined were less than those observed with Cu(II) and copper displaced other metals except Ag(I) and Au(III) bound to mb. However, the binding of different metals by mb suggests that methanotrophic activity also may play a role in either the solubilization or immobilization of many metals in situ.

  1. Adsorption character for removal Cu(II) by magnetic Cu(II) ion imprinted composite adsorbent.

    PubMed

    Ren, Yueming; Wei, Xizhu; Zhang, Milin

    2008-10-01

    A novel magnetic Cu(II) ion imprinted composite adsorbent (Cu(II)-MICA) was synthesized, characterized and applied for the selective removal Cu(II) from aqueous solution in the batch system. The adsorption-desorption and selectivity characteristics were investigated. The maximum adsorption occurred at pH 5-6. The equilibrium time was 6.0h, and a pseudo-second-order model could best describe adsorption kinetics. The adsorption equilibrium data fit Langmuir isotherm equation well with a maximum adsorption capacity of 46.25mg/g and Langmuir adsorption equilibrium constant of 0.0956L/mg at 298K. Thermodynamic parameters analysis predicted an exothermic nature of adsorption and a spontaneous and favourable process that could be mainly governed by physisorption mechanism. The relative selectivity coefficients of Cu(II)-MICA for Cu(II)/Zn(II) and Cu(II)/Ni(II) were 2.31, 2.66 times greater than the magnetic non-imprinted composite adsorbent (MNICA). Results suggested that Cu(II)-MICA was a material of efficient, low-cost, convenient separation under magnetic field and could be reused five times with about 14% regeneration loss.

  2. On Cu(II) Cu(II) distance measurements using pulsed electron electron double resonance

    NASA Astrophysics Data System (ADS)

    Yang, Zhongyu; Becker, James; Saxena, Sunil

    2007-10-01

    The effects of orientational selectivity on the 4-pulse electron electron double resonance (PELDOR) ESR spectra of coupled Cu(II)-Cu(II) spins are presented. The data were collected at four magnetic fields on a poly-proline peptide containing two Cu(II) centers. The Cu(II)-PELDOR spectra of this peptide do not change appreciably with magnetic field at X-band. The data were analyzed by adapting the theory of Maryasov, Tsvetkov, and Raap [A.G. Maryasov, Y.D. Tsvetkov, J. Raap, Weakly coupled radical pairs in solids:ELDOR in ESE structure studies, Appl. Magn. Reson. 14 (1998) 101-113]. Simulations indicate that orientational effects are important for Cu(II)-PELDOR. Based on simulations, the field-independence of the PELDOR data for this peptide is likely due to two effects. First, for this peptide, the Cu(II) g-tensor(s) are in a very specific orientation with respect to the interspin vector. Second, the flexibility of the peptide washes out the orientation effects. These effects reduce the suitability of the poly-proline based peptide as a good model system to experimentally probe orientational effects in such experiments. An average Cu(II)-Cu(II) distance of 2.1-2.2 nm was determined, which is consistent with earlier double quantum coherence ESR results.

  3. Synthesis, spectroscopic, fluorescence properties and biological evaluation of novel Pd(II) and Cd(II) complexes of NOON tetradentate Schiff bases.

    PubMed

    Ali, Omyma A M

    2014-01-01

    The solid complexes of Pd(II) and Cd(II) with N,N/bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L(1)), and N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L(2)) have been synthesized and characterized by several techniques using elemental analysis (CHN), FT-IR, (1)H NMR, UV-Vis spectra and thermal analysis. Elemental analysis data proved 1:1 stoichiometry for the reported complexes while spectroscopic data indicated square planar and octahedral geometries for Pd(II) and Cd(II) complexes, respectively. The prepared ligands, Pd(II) and Cd(II) complexes exhibited intraligand (π-π(∗)) fluorescence and can potentially serve as photoactive materials. Thermal behavior of the complexes was studied and kinetic parameters were determined by Coats-Redfern method. Both the ligands and their complexes have been screened for antimicrobial activities.

  4. The analysis of the immobilization mechanism of Ni(II) on Bacillus cereus.

    PubMed

    Pan, Xiaohong; Chen, Zhi; Cheng, Yangjian; Pan, Danmei; Yin, Shungao; Huang, Feng; Guan, Xiong; Lin, Zhang

    2011-04-01

    This work focused on the identification of biosorption mechanism of Ni(II) by living Bacillus cereus (B. cereus) based on batch experiments and a variety of microscopic equipments. The adsorption equilibrium reached rapidly in 2 h and the maximum nickel adsorption capability of B. cereus was 17.7 mg x g(-1) (dry weight). Atomic force microscopy (AFM) analysis showed that the bacterial surface roughness increased from 7.9 +/- 0.5 nm to 12.6 +/- 1.6 nm during this process. Scanning electron microscopy (SEM) observation confirmed that there was Ni(II) on the bacterial surface. However, transmission electron microscopy (TEM) thin section analysis coupled with energy dispersive X-ray spectroscopy (EDS) revealed that Ni(II) could also be found in the inner portions of the bacteria. Inductive coupled plasma emission spectrometer (ICP-OES) quantitative analysis elucidated that over 70% of the immobilized Ni(II) was binding on the surface of bacteria. X-ray diffraction (XRD) analysis showed that the Ni(II) collected by the bacteria was amorphous. Fourier transform infrared (FT-IR) analysis indicated that amides and carboxylation functional groups might be involved in the coordination of Ni(II).

  5. Biosorption of Ni(II) from aqueous solutions by Litchi chinensis seeds.

    PubMed

    Flores-Garnica, Jonathan Gonzalo; Morales-Barrera, Liliana; Pineda-Camacho, Gabriela; Cristiani-Urbina, Eliseo

    2013-05-01

    The potential of Litchi chinensis seeds (LCS) for biosorption of Ni(II) ions from aqueous solutions was investigated in batch systems in terms of kinetics, equilibrium and thermodynamics. Experimental data showed that the biosorption capacity of LCS was dependent on operating variables such as solution pH, initial Ni(II) concentration, contact time, and temperature. The optimum pH value for Ni(II) biosorption was 7.5. Significant enhancement of Ni(II) biosorption was observed by increasing initial metal concentration and temperature. Modeling of sorption kinetics showed good agreement of experimental data with the pseudo-second-order kinetic model. Langmuir model exhibited the best fit to experimental data. According to this isotherm model, the maximum Ni(II) biosorption capacity of LCS is 66.62 mg g(-1). The calculated thermodynamic parameters showed that the biosorption of Ni(II) ions is an endothermic and non-spontaneous process. Results indicate that LCS can be used as an effective and environmentally friendly biosorbent to detoxify Ni(II)-polluted wastewaters.

  6. Structural consequences of spin conversion in a sterically encumbered Ni(II) porphyrin

    SciTech Connect

    Barkigia, K.M.; Nelson, N.Y.; Renner, M.W.; Smith, K.M.; Fajer, J.

    1999-10-14

    The crystal structure of a pyridine-ligated, high-spin Ni(II) complex of 2,3,7,8,12,13,17,18-octabromo-5, 15-bis(isopropyl)-10,20-bis(isopropylidenyl) porphyrin, is reported and compared to the unligated, low-spin Ni(II) complex previously reported. The results demonstrate that conversion to high-spin Ni(II) in nonplanar, sterically encumbered porphyrins induces a significant core expansion about the Ni while nonplanarity is still retained. The expansion of the core parameters (Ni-N, Ct-C{alpha}, Ct-Cmexo) and the Ni-N{sub axial} distances are characteristic of the d{sub x{sup 2}{minus}y{sup 2}} orbital occupancies in high-spin Ni(II) porphyrins and document the structural consequences of the spin conversion in severely nonplanar Ni(II) porphyrins. The stereochemical results are particularly relevant to ligation effects in nonplanar Ni biomolecules and synthetic porphyrins increasingly used as biomimetic models of conformational effects in chromophores and prosthetic groups in vivo, and to the remarkably wide range of lifetimes observed for excited (d,d) states in nonplanar, sterically constrained Ni(II) porphyrins in which the d{sub x{sup 2}{minus}y{sup 2}} and d{sub z{sup 2}} orbitals are also populated.

  7. Metal-ion exchange induced structural transformation as a way of forming novel Ni(II)- and Cu(II)-salicylaldimine structures

    NASA Astrophysics Data System (ADS)

    Wu, Jing-Yun; Tsai, Chi-Jou; Chang, Ching-Yun; Wu, Yung-Yuan

    2017-02-01

    A Zn(II)-salicylaldimine complex [Zn(Lsalpyca)(H2O)]n (1, where H2Lsalpyca=4-hydroxy-3-(((pyridin-2-yl)methylimino)methyl)benzoic acid), with a one-dimensional (1D) chain structure, has been successfully converted to a discrete Ni(II)-salicylaldimine complex [Ni(Lsalpyca)(H2O)3] (2) and an infinite Cu(II)-salicylaldimine complex {[Cu(Lsalpyca)]·3H2O}n (3) through a metal-ion exchange induced structural transformation process. However, such processes do not worked by Mn(II) and Co(II) ions. Solid-state structure analyses reveal that complexes 1-3 form comparable coordinative or supramolecular zigzag chains running along the crystallographic [201] direction. In addition, replacing Zn(II) ion by Ni(II) and Cu(II) ions caused changes in coordination environment and sphere of metal centers, from a 5-coordinate intermediate geometry of square pyramidal and trigonal bipyramidal in 1 to a 6-coordinate octahedral geometry in 2, and to a 4-coordiante square planar geometry in 3. This study shows that metal-ion exchange serves as a very efficient way of forming new coordination complexes that may not be obtained through direct synthesis.

  8. Determination of Pd(II) using an antimony film coated on a screen-printed electrode by adsorptive stripping voltammetry.

    PubMed

    Pérez-Ràfols, Clara; Trechera, Pedro; Serrano, Núria; Díaz-Cruz, José Manuel; Ariño, Cristina; Esteban, Miquel

    2017-05-15

    The use of an antimony film coated on a screen-printed carbon electrode (ex-situ SbSPCE) is proposed for the determination of Pd(II) at ppb levels in natural samples by adsorptive stripping voltammetry using dimethylglyoxime as chelating agent. Ex-situ SbSPCE produces a better analytical performance as compared to a commercially sputtered bismuth screen-printed electrode (BispSPE). The detection and quantification limits were 2.7 and 9.0µgL(-1) respectively with a good linear behaviour in the wide examined concentration range (from 1µgL(-1) up to 100.0µgL(-1), R(2)=0.998). The proposed ex-situ SbSPCE showed an excellent repeatability with a relative standard deviation of 0.5% for ten successive measurements and a very good reproducibility (1.6% for three different ex-situ SbSPCE units within series of ten repetitive assays). Moreover, the ex-situ SbSPCE was successfully applied for the determination of low concentration levels of Pd(II) in spiked tap water with a very high reproducibility (0.2%) and providing equivalent results to those achieved by ICP-MS measurements.

  9. Cytosolic Ni(II) sensor in cyanobacterium: nickel detection follows nickel affinity across four families of metal sensors.

    PubMed

    Foster, Andrew W; Patterson, Carl J; Pernil, Rafael; Hess, Corinna R; Robinson, Nigel J

    2012-04-06

    Efflux of surplus Ni(II) across the outer and inner membranes of Synechocystis PCC 6803 is mediated by the Nrs system under the control of a sensor of periplasmic Ni(II), NrsS. Here, we show that the product of ORF sll0176, which encodes a CsoR/RcnR-like protein now designated InrS (for internal nickel-responsive sensor), represses nrsD (NrsD is deduced to efflux Ni(II) across the inner membrane) from a cryptic promoter between the final two ORFs in the nrs operon. Transcripts initiated from the newly identified nrsD promoter accumulate in response to nickel or cobalt but not copper, and recombinant InrS forms specific, Ni(II)-inhibited complexes with the nrsD promoter region. Metal-dependent difference spectra of Ni(II)- and Cu(I)-InrS are similar to Cu(I)-sensing CsoR and dissimilar to Ni(II)/Co(II)-sensing RcnR, consistent with factors beyond the primary coordination sphere switching metal selectivity. Competition with chelators mag-fura-2, nitrilotriacetic acid, EDTA, and EGTA estimate K(D) Ni(II) for the tightest site of InrS as 2.05 (±1.5) × 10(-14) m, and weaker K(D) Ni(II) for the cells' metal sensors of other types: Zn(II) co-repressor Zur, Co(II) activator CoaR, and Zn(II) derepressor ZiaR. Ni(II) transfer to InrS occurs upon addition to Ni(II) forms of each other sensor. InrS binds Ni(II) sufficiently tightly to derepress Ni(II) export at concentrations below K(D) Ni(II) of the other sensors.

  10. Adsorption characteristics of Ni(II) onto MA-DTPA/PVDF chelating membrane.

    PubMed

    Zhao, Xiaodan; Song, Laizhou; Fu, Jie; Tang, Pei; Liu, Feng

    2011-05-30

    The melamine-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (MA-DTPA/PVDF) chelating membrane bearing polyaminecarboxylate groups was prepared for the removal of Ni(II) from wastewater effluents. The membrane was characterized by SEM, (13)C NMR and FTIR techniques. Quantitative adsorption experiments were performed in view of pH, contact time, temperature, the presence of Ca(II) and lactic acid as the controlling parameters. Adsorption kinetics and equilibrium were examined regarding the single Ni(II) system, binary Ni(II) and Ca(II) system and nickel-lactic acid complexes system. The desorption efficiency was also evaluated, and the adsorption mechanism was suggested based on experimental data. The results show that the sorption kinetics fit well to Lagergren second-order equation and the isotherms can be well described by Langmuir model. At 298 K, the second-order rate constant is calculated to be 4.171, 11.39, 6.203 cm(2)/(mg min) and the equilibrium uptake is 0.0264, 0.0211 and 0.0216 mg/cm(2) in the aforementioned three systems. The distribution coefficient of Ni(II) slowly decreases from 4.27 to 2.72, and the separation factor (f(Ni(II)/Ca(II))) increases from 3.10 to 8.46 when the initial Ca(II) concentration varies from 20 to 200mg/L. This reveals the chelating membrane shows more affinity for Ni(II) than Ca(II) ions. In the studied range of lactic acid concentration, Ni(II) uptake decreases with the maximum ratio of 10%. Chemical bonding (chelation) dominates in the adsorption process, and the negative ΔG° and ΔH° indicate the spontaneous and exothermic nature of adsorption.

  11. Synthesis, characterization and anticancer studies of Ni(II), Pd(II) and Pt(II) complexes with Schiff base derived from N-methylhydrazinecarbothioamide and 2-hydroxy-5-methoxy-3-nitrobenzaldehyde

    NASA Astrophysics Data System (ADS)

    Arafath, Md. Azharul; Adam, Farook; Razali, Mohd. R.; Ahmed Hassan, Loiy E.; Ahamed, Mohamed B. Khadeer; Majid, Amin Malik S. A.

    2017-02-01

    A carbothioamide NSO tridentate Schiff base ligand (HL) and its square planar complexes Na[NiLOAc], Na[PdLOAc] and [PtLdmso] have been synthesized and characterized on the basis of melting point, elemental analysis, FT-IR, 1H NMR, 13C NMR, UV-Vis spectra. The structure of HL was elucidated with X-ray diffraction analysis. In the present study, the synthesized compounds were evaluated for their anticancer properties against three human cancer cell lines breast cancer (MCF-7), cervical (Hela), and colon (HCT-116). In addition, the cytotoxicity of the synthesized compounds was tested on a normal human cell line (human endothelial cell line EA.hy926). Among the tested compounds, the complex [NiLOAc] excelled in halting proliferation of the cervical and colon cancer cells with median inhibitory concentration (IC50) values of 28.33 and 34.4 μM, respectively. The complex, [PdLOAc] demonstrated selective cytotoxicity against breast cancer line MCF-7 with IC50 = 47.5 μM, while HL showed inhibitory effect against colon cancer cell line (HCT-116) with IC50 = 55.66 μM. The complex, [PtLdmso] showed mild activity against breast cancer (MCF-7) and cervical cancer (Hela) cells with IC50 = 64.44 and 68.3 μM, respectively, whereas, it displayed insignificant cytotoxicity against human endothelial cells (EA.hy926) with IC50 > 200 μM. Cancer cells treated with [NiLOAc] showed apoptotic features such as membrane blebbing and DNA condensation. Thus, the findings of the present study demonstrated that the series of metal complexes of HL could form the new lead for development of cancer chemotherapies to treat human cervical, breast and colon malignancies.

  12. Co(II), Ni(II) and Cu(II) complexes of methyl-5-(Phenylthio) benzimidazole-2-carbamate: Molecular structures, spectral and DFT calculations

    NASA Astrophysics Data System (ADS)

    Mansour, Ahmed M.; El Bakry, Eslam M.; Abdel-Ghani, Nour T.

    2016-05-01

    [Co(FBZ)2(H2O)]·2NO3·0.5H2O (1), [Ni(FBZ)2X2]·zH2O (X = Cl​-, z = 0.5 (2) and X = CH3COO-, z = 1 (3)) and [Cu(FBZ)2(H2O) (NO3)]·NO3·1.5H2O (4) (FBZ = methyl-5-(Phenylthio) benzimidazole-2-carbamate; Fenbendazole) complexes were synthesized and characterized by elemental analysis, thermal, IR, EPR, UV-Vis, magnetic and conductance measurements. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were carried out at DFT/B3LYP/6-31G∗ level of theory. FBZ behaves as a neutral bidentate ligand via the pyridine-type nitrogen of the benzimidazole moiety and the carbamate group. Three-step ionization with pKa values of 3.38, 4.06 and 10.07 were reported for FBZ. The coordination of FBZ to the metal ions led to an increase in the antibacterial activity against the tested Staphylococcus aureus and Escherichia coli bacteria.

  13. Characteristics of equilibrium, kinetics studies for adsorption of Hg(II), Cu(II), and Ni(II) ions by thiourea-modified magnetic chitosan microspheres.

    PubMed

    Zhou, Limin; Wang, Yiping; Liu, Zhirong; Huang, Qunwu

    2009-01-30

    Magnetic chitosan microspheres were prepared and chemically modified with thiourea (TMCS) for adsorption of metal ions. TMCS obtained were investigated by means of X-ray diffraction (XRD), IR, magnetic properties and thermogravimetric analysis (TGA). The adsorption properties of TMCS toward Hg(2+), Cu(2+), and Ni(2+) ions were evaluated. Various factors affecting the uptake behavior such as contact time, temperature, pH and initial concentration of the metal ions were investigated. The kinetics was evaluated utilizing the pseudo-first-order, pseudo-second-order, and the intra-particle diffusion models. The equilibrium data were analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorption mechanism and not involving a mass transfer in solution. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 625.2, 66.7, and 15.3mg/g for Hg(2+), Cu(2+), and Ni(2+) ions, respectively. TMCS displayed higher adsorption capacity for Hg(2+) in all pH ranges studied. The adsorption capacity of the metal ions decreased with increasing temperature. The metal ion-loaded TMCS with were regenerated with an efficiency of greater than 88% using 0.01-0.1M ethylendiamine tetraacetic acid (EDTA).

  14. One-pot synthesis, structural characterization, UV-Vis and electrochemical analyses of new Schiff base complexes of Fe(III), Ni(II) and Cu(II)

    NASA Astrophysics Data System (ADS)

    Back, Davi Fernando; de Oliveira, Gelson Manzoni; Fontana, Liniquer Andre; Ramão, Brenda Fiorin; Roman, Daiane; Iglesias, Bernardo Almeida

    2015-11-01

    The complexes [Ni(Pyr2tetam-2H)]·2H2O (1) (Pyr2tetam = (pyridoxyl)2-N1,N4-triethylenetetramine), [Fe(Pyr2tetam-2H)](ClO4)·H2O (2) and [Cu(Pyrtetam-H)](ClO4) (3) (Pyrtetam = pyridoxyl-N1-triethylenetetramine) were obtained through one pot reactions of triethylenetetramine, pyridoxal chloridrate, triethylamine and the metal salts Ni(ClO4)2·6H2O, Fe(ClO4)2·6H2O and Cu(ClO4)2·6H2O. In complexes 1 and 2 the metal centers present a distorted octahedral coordination, while complex 3 shows a square pyramidal configuration. The structures were characterized through X-ray diffractometry, IR and UV-Vis spectra. Cyclic voltammograms of the title compounds are also presented and discussed.

  15. Zn(II), Ni(II), Cu(II) and Pb(II) complexes of tridentate asymmetrical Schiff base ligands: Synthesis, characterization, properties and biological activity

    NASA Astrophysics Data System (ADS)

    Şahin, Mustafa; Koçak, Nuriye; Erdenay, Damla; Arslan, Uğur

    2013-02-01

    New asymmetrical tridentate Schiff base ligands were synthesized using 1,2-phenylenediamine, 4-methyl-1,2-phenylenediamine, 2-hydroxy-1-napthaldehyde, 9-anthracenecarboxaldehyde. Schiff base ligands and their metal complexes were synthesised and characterized by using FT-IR, 1H NMR, 13C NMR, UV-Vis, XRD, ESR, elemental analysis and fluorescence studies. The antimicrobial activity of the ligands and their metal complexes were studied against Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, Streptococcus mutans RSHM 676, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The determination of the antibacterial activity was done using the broth microdilution methods. In general, it has been determined that the studied compounds have MIC values similar to Gram-positive and Gram-negative bacteria. It has been found that Ni, Pb, Zn derivatives of HL1A and ZnL2A has lower MIC values than ampicillin for P. aeruginosa ATCC 27853 strain.

  16. Molecular tectonics: homochiral coordination networks based on combinations of a chiral neutral tecton with Hg(II), Cu(II) or Ni(II) neutral complexes as metallatectons.

    PubMed

    Larpent, Patrick; Jouaiti, Abdelaziz; Kyritsakas, Nathalie; Hosseini, Mir Wais

    2014-02-07

    The use of compound 1 as an enantiomerically pure neutral and rigid organic linear tecton bearing two divergently oriented monodentate coordinating sites appended with two chiral centres of the same (S) configuration leads, in the presence of neutral metal complexes behaving either as a linear (Cu(hfac)2, Cu(OAc)2) or a V-shaped (HgCl2) 2-connecting node or a 4-connecting square node (NiCl2), to the formation of four homochiral 1- and 2-D coordination polymers.

  17. Phenoxide bridged tetranuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes: Electrochemical, magnetic and antimicrobial studies

    NASA Astrophysics Data System (ADS)

    Kamath, Anupama; Kulkarni, Naveen V.; Netalkar, Priya P.; Revankar, Vidyanand K.

    2011-09-01

    Phenoxide bridged later first row transition metal(II) complexes have been prepared by the interaction of later 3d transition metal(II) chlorides with tetranucleating compartmental Schiff base ligand system derived from 2,6-diformyl-4-methylphenol, p-phenylenediamine and 2-hydrazinobenzothiazole. Ligand and complexes were characterized by analytical, spectral (IR, UV-visible, ESR, FAB-mass and fluorescence), magnetic and thermal studies. All complexes are found to have octahedral geometry. The mutual influence of metal centres in terms of cooperative effect on the electronic, magnetic, electrochemical and structural properties was investigated. The Schiff base and its complexes have been screened for their antibacterial (against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa) and antifungal activities (against Aspergillus niger, and Candida albicans).

  18. Simultaneous preconcentration of Co(II), Ni(II), Cu(II), and Cd(II) from environmental samples on Amberlite XAD-2000 column and determination by FAAS.

    PubMed

    Duran, Celal; Senturk, Hasan Basri; Elci, Latif; Soylak, Mustafa; Tufekci, Mehmet

    2009-02-15

    A new method for the preconcentration of some trace metals (Co, Ni, Cu, and Cd) as complexed with ammonium pyrrolidynedithiocarbamate (APDC) was developed using a mini-column filled with Amberlite XAD-2000 resin. Metal contents were determined by flame atomic absorption spectrometry (FAAS) after the metal complexes accumulated on the resin were eluted with 1M HNO(3) in acetone. The effects of the analytical parameters such as sample pH, quantity of complexing agent, eluent type, resin quantity, sample volume, sample flow rate, and matrix ions were investigated on the recovery of the metals from aqueous solutions. The relative standard deviation (R.S.D.) of the method was <6%. The validation of the method was confirmed using two certified reference materials (CRM TMDW-500 Drinking Water and CRM SA-C Sandy Soil C). The method was successfully applied to some stream waters and mushroom samples from Eastern Black Sea Region (Trabzon city) of Turkey.

  19. Highly efficient removal of Cu(II), Zn(II), Ni(II) and Fe(II) from electroplating wastewater using sulphide from sulphidogenic bioreactor effluent.

    PubMed

    Fang, Di; Zhang, Ruichang; Deng, Wenjing; Li, Jie

    2012-01-01

    A bench-scale, stirred-tank batch precipitator was used to assess the selective removal of Cu2+, Zn2+, Ni2+ and Fe2+ from acidic electroplating wastewater using sulphide from a sulphidogenic bioreactor effluent. At pH approximately 1.7, >99% of Cu was selectively precipitated, over Zn, Ni and Fe, from the wastewater as pure CuS by recycling H2S from the bioreactor effluent via N2 sparging, resulting in a Cu effluent concentration <0.4 mg/L. The rate of Cu precipitation increased from 1.6 to 6.4 mg Cu/(L x min) when the pH of the bioreactor effluent decreased from 7.5 to 5.5. Experiments focusing on the precipitation of Zn, Ni and Fe from the wastewater devoid of Cu (at pH approximately 1.7), using sulphide-rich bioreactor effluent, achieved approximately 85-97% precipitation efficiency for Zn, approximately 25-92% for Ni, and approximately 2-99% for Fe, depending on the initial sulphide/metal molar ratio. The sulphide/metal ratio of 1.76 was found to be optimal for the precipitation of Zn, Ni and Fe with sulphides and, to a lesser extent, with hydroxides, resulting in residual metal concentrations of 1 mg Zn/L, 3 mg Ni/L, and 0.5 mg Fe/L. These findings suggest the potential of waste biogenic sulphides for the selective recovery of valuable metals from acidic metal-rich industrial wastewaters.

  20. Spectroscopic and theoretical study of Cu(II), Zn(II), Ni(II), Co(II) and Cd(II) complexes of glyoxilic acid oxime

    NASA Astrophysics Data System (ADS)

    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.

  1. Spectroscopic and theoretical study of Cu(II), Zn(II), Ni(II), Co(II) and Cd(II) complexes of glyoxilic acid oxime.

    PubMed

    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 (gaoH2), Cu(gaoH)2(H2O)2 (1), Zn(gaoH)2(H2O)2 (2), Co(gaoH)2(H2O)2 (3), Ni(gaoH)2(H2O)2 (4) and [Cd(gaoH)2(H2O)2].H2O (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 nu(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. Synthesis, Characterization, Electrochemical Studies, and In Vitro Antibacterial Activity of Novel Thiosemicarbazone and Its Cu(II), Ni(II), and Co(II) Complexes

    PubMed Central

    Khan, Salman A.; Asiri, Abdullah M.; Al-Amry, Khalid; Malik, Maqsood Ahmad

    2014-01-01

    Metal complexes were prepared by the reaction of thiosemicarbazone with CuCl2, NiCl2, CoCl2, Cu(OAc)2, Ni(OAc)2, and Co(OAc)2. The thiosemicarbazone coordinates to metal through the thionic sulfur and the azomethine nitrogen. The thiosemicarbazone was obtained by the thiosemicarbazide with 3-acetyl-2,5-dimethylthiophene. The identities of these compounds were elucidated by IR, 1H, 13C-NMR, and GC-MS spectroscopic methods and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined by using chloramphenicol as reference drug. The results showed that compound 1.1 is better inhibitor of both types of tested bacteria as compared to chloramphenicol. PMID:24523641

  3. Phenoxide bridged tetranuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes: electrochemical, magnetic and antimicrobial studies.

    PubMed

    Kamath, Anupama; Kulkarni, Naveen V; Netalkar, Priya P; Revankar, Vidyanand K

    2011-09-01

    Phenoxide bridged later first row transition metal(II) complexes have been prepared by the interaction of later 3d transition metal(II) chlorides with tetranucleating compartmental Schiff base ligand system derived from 2,6-diformyl-4-methylphenol, p-phenylenediamine and 2-hydrazinobenzothiazole. Ligand and complexes were characterized by analytical, spectral (IR, UV-visible, ESR, FAB-mass and fluorescence), magnetic and thermal studies. All complexes are found to have octahedral geometry. The mutual influence of metal centres in terms of cooperative effect on the electronic, magnetic, electrochemical and structural properties was investigated. The Schiff base and its complexes have been screened for their antibacterial (against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa) and antifungal activities (against Aspergillus niger, and Candida albicans).

  4. Zn(II), Ni(II), Cu(II) and Pb(II) complexes of tridentate asymmetrical Schiff base ligands: synthesis, characterization, properties and biological activity.

    PubMed

    Şahin, Mustafa; Koçak, Nuriye; Erdenay, Damla; Arslan, Uğur

    2013-02-15

    New asymmetrical tridentate Schiff base ligands were synthesized using 1,2-phenylenediamine, 4-methyl-1,2-phenylenediamine, 2-hydroxy-1-napthaldehyde, 9-anthracenecarboxaldehyde. Schiff base ligands and their metal complexes were synthesised and characterized by using FT-IR, (1)H NMR, (13)C NMR, UV-Vis, XRD, ESR, elemental analysis and fluorescence studies. The antimicrobial activity of the ligands and their metal complexes were studied against Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, Streptococcus mutans RSHM 676, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The determination of the antibacterial activity was done using the broth microdilution methods. In general, it has been determined that the studied compounds have MIC values similar to Gram-positive and Gram-negative bacteria. It has been found that Ni, Pb, Zn derivatives of HL1A and ZnL(2)A has lower MIC values than ampicillin for P. aeruginosa ATCC 27853 strain.

  5. Axially chiral monomeric and dimeric square planar Pd(II) complexes and their application to chiral tectonics.

    PubMed

    Sato, Hisako; Morimoto, Kazuya; Mori, Yukie; Shinagawa, Yuji; Kitazawa, Takafumi; Yamagishi, Akihiko

    2013-06-07

    Mononuclear and dinuclear square planar palladium(II) complexes (denoted by [(hfac)Pd(II)(L-LH)] and [(hfac)Pd(II)(L-L)Pd(II)(hfac)], respectively) were synthesized. Here hfac(-), HL-L(-) and L-L(2-) denote hexafluoroacetylacetonato, monoprotonated and non-protonated bis-β-diketonato ligands, respectively. Three bis-β-diketones were used as HL-LH: 1,2-diacetyl-1,2-dibenzoylethane (denoted by dabeH2), 1,2-diacetyl-1,2-bis(3-methylbutanoyl)ethane (baetH2) and 1,2-diacetyl-1,2-propanoylethane (dpeH2). Both the monomeric and dimeric Pd(II) complexes were chiral due to the orthogonal twisting of the two non-symmetric diketonato moieties in HL-L(-) and L-L(2-), respectively. Optical resolution of [(hfac)Pd(II)(dabe)Pd(II)(hfac)] was achieved chromatographically on a chiral column to obtain a pair of optical antipodes which were stable against racemization. As for the other complexes, resolution was possible only after replacing hfac(-) with a bulky ligand such as dibenzoylmethanato (dbm(-)). Although a dinuclear complex with a symmetric bis-β-diketonato ligand, [(hfac)Pd(II)(taet)Pd(II)(hfac)] (taet(2-) = 1,1,2,2-tetraacetylethanato), was achiral, the replacement of the terminal ligands with non-symmetric β-diketonates yielded an axially chiral complex such as [(phacac)Pd(II)(taet)Pd(II)(phacac)], wherein phacac(-) denotes 1-phenyl-1,3-butanedionato. The UV and CD spectra of the Pd(II) complexes were analyzed with the help of the TDDFT calculations. The chiral monomeric species, [(dbm)Pd(II)(R- or S-baetH)], formed a heterometallic tetranuclear complex, [Fe(III){(dbm)Pd(II)(R- or S-baet)}3], in methanol solution.

  6. Metal Zn(II), Cu(II), Ni (II) complexes of ursodeoxycholic acid as putative anticancer agents

    PubMed Central

    Dyakova, Lora; Culita, Daniela-Cristina; Marinescu, Gabriela; Alexandrov, Marin; Kalfin, Reni; Patron, Luminita; Alexandrova, Radostina

    2014-01-01

    The aim of the study was to evaluate the influence of metal [Zn(II), Cu(II), Ni(II)] complexes with ursodeoxycholic acid (UDCA) on the viability and proliferation of tumour and non-tumour cells. Cell lines established from retrovirus-transformed chicken hepatoma (LSCC-SF-Mc29) and rat sarcoma (LSR-SF-SR) as well as from human cancers of the breast (MCF-7), uterine cervix (HeLa), lung (A549) and liver (HepG2) were used as model systems. Non-tumour human embryo (Lep-3) cells were also included in some of the experiments. The investigations were carried out by the thiazolyl blue tetrazolium bromide (MTT) test, neutral red uptake cytotoxicity assay, crystal violet staining, double staining with acridine orange and propidium iodide and the colony-forming method. The results obtained revealed that: (1) UDCA and its metal complexes in the tested concentrations decreased (to a varying degree) the viability and proliferation of the treated cells in a time- and concentration-dependent manner; (2) chicken hepatoma (LSCC-SF-Mc29) cells were most sensitive to the cytotoxic and antiproliferative action of the compounds tested, followed by rat sarcoma (LSR-SF-SR) cells; (3) Cu‒UDCA and Ni‒UDCA were more effective against animal LSCC-SF-Mc29 and LSR-SF-SR cells, while Zn‒UDCA significantly decreased the viability and proliferation of human tumour cell lines; (4) applied independently, UDCA expressed lower cytotoxic/cytostatic activity as compared to metal complexes; and (5) the sensitivity of the non-tumour embryonic Lep-3 cells to the effects of UDCA and its metal complexes was comparable or even higher than those of the human tumour cells. PMID:26019542

  7. Comparative studies and modeling structures of two new isomers containing binuclear PdII complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPTZ).

    PubMed

    Al-Assy, Waleed H; Mostafa, Mohsen M

    2014-01-01

    The synthesis and comparative studies of two new binuclear PdII isomer complexes derived from TPTZ, [2,4,6-tri-(2-pyridyl)-1,3,5-triazine], have been synthesized and characterized. Their structures have been investigated by elemental analyses, spectral (IR, UV-vis, mass and 1H-NMR) and thermal measurements. Electronic and magnetic studies suggest a distorted square-planar around the two PdII ions. The HOMO, LUMO and DFT parameters on the atoms have been calculated to confirm the geometry of the ligand and their complexes. Kinetic parameters were determined using Coats-Redfern and Horowitz-Metzger methods. Also, the geometry of the two isomers is confirmed using DFT method from DMOL3 calculations. Moreover, the two PdII complexes have different specific optical rotation where the red PdII complex has dextrorotatory (+5.68) while the yellow PdII complex has levorotatory (-9.37). The results of biological activity for the two PdII complexes promised to be effective in tumor treatment.

  8. Adsorption of Cu(II) ions on cotton boll.

    PubMed

    Ozsoy, H Duygu; Kumbur, Halil

    2006-08-25

    In this study, cotton boll was used as an adsorbent for the aim of removing of the Cu(II) ions from the aqueous solutions. The adsorption process was carried out in a batch process and the effects of contact time (2-24h), adsorbent concentration (1-20 g l(-1)), initial pH (2.0-6.0), initial metal ion concentration (20-160 mg l(-1)) and temperature (20-45 degrees C) on the adsorption were investigated. Experimental results showed that the maximum adsorption capacity was determined at pH 5.0 and adsorbed Cu(II) ion concentration was increased with increasing adsorbent concentration and contact time. The isothermal data of cotton boll could be well described by the Langmuir equations and the Langmuir monolayer capacity had a mean value of 11.40 mg g(-1). Experimental results indicated that the pseudo-second order reaction model provided the best description of the data with a correlation coefficient 0.99 for different initial metal concentrations and therefore it was explained that chemical sorption was the basic mechanism in this system. FT-IR results showed that oxygen and nitrogen atoms in structure of cotton boll were involved in Cu(II) ions adsorption.

  9. Study on Adsorption of Cu(II) on Chitosan Nanofiber Membranes

    NASA Astrophysics Data System (ADS)

    Cao, Jianhua; Li, Dongzhou; Liang, Weihua; Wu, Dayong

    2014-12-01

    Chitosan nanofiber membranes by electrospinning technique were used to remove Cu(II) from aqueous solution. The adsorption kinetics, equilibrium isotherms, and pH effect were investigated in batch experiments. The Langmuir isotherm and pseudo second-order kinetic models agree well with the experimental data. The chitosan nanofiber membranes are effective for Cu(II) adsorption at pH6. Results showed that the maximum adsorption capacity of the chitosan nanofiber membranes with Cu(II) is 118.62 mg g-1. The chitosan nanofiber membranes can be used as an effective adsorbent for the removal of Cu(II) in aqueous solution due to high adsorption capacity.

  10. Secondary Structure and Pd(II) Coordination in S-Layer Proteins from Bacillus sphaericus Studied by Infrared and X-Ray Absorption Spectroscopy

    PubMed Central

    Fahmy, Karim; Merroun, Mohamed; Pollmann, Katrin; Raff, Johannes; Savchuk, Olesya; Hennig, Christoph; Selenska-Pobell, Sonja

    2006-01-01

    The S-layer of Bacillus sphaericus strain JG-A12, isolated from a uranium-mining site, exhibits a high metal-binding capacity, indicating that it may provide a protective function by preventing the cellular uptake of heavy metals and radionuclides. This property has allowed the use of this and other S-layers as self-assembling organic templates for the synthesis of nanosized heavy metal cluster arrays. However, little is known about the molecular basis of the metal-protein interactions and their impact on secondary structure. We have studied the secondary structure, protein stability, and Pd(II) coordination in S-layers from the B. sphaericus strains JG-A12 and NCTC 9602 to elucidate the molecular basis of their biological function and of the metal nanocluster growth. Fourier transform infrared spectroscopy reveals similar secondary structures, containing ∼35% β-sheets and little helical structure. pH-induced infrared absorption changes of the side-chain carboxylates evidence a remarkably low pK < 3 in both strains and a structural stabilization when Pd(II) is bound. The COO−-stretching absorptions reveal a predominant Pd(II) coordination by chelation/bridging by Asp and Glu residues. This agrees with XANES and EXAFS data revealing oxygens as coordinating atoms to Pd(II). The additional participation of nitrogen is assigned to side chains rather than to the peptide backbone. The topology of nitrogen- and carboxyl-bearing side chains appears to mediate heavy metal binding to the large number of Asp and Glu in both S-layers at particularly low pH as an adaptation to the environment from which the strain JG-A12 has been isolated. These side chains are thus prime targets for the design of engineered S-layer-based nanoclusters. PMID:16698775

  11. Potentiometric, spectroscopic and thermal studies on the metal chelates of 1-(2-thiazolylazo)-2-naphthalenol

    NASA Astrophysics Data System (ADS)

    Omar, M. M.; Mohamed, Gehad G.

    2005-03-01

    The synthesis and characterization of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pd(II) and UO 2(II) chelates of 1-(2-thiazolylazo)-2-naphthalenol (TAN) were reported. The dissociation constants of the ligand and the stability constants of the metal complexes were calculated pH-metrically at 25 °C and 0.1 M ionic strength. The solid complexes were characterized by elemental and thermal analyses, molar conductance, IR, magnetic and diffuse reflectance spectra. The complexes were found to have the formulae [M(L) 2] for M = Mn(II), Co(II), Ni(II), Zn(II) and Cd(II); [M(L)X]· nH 2O for M = Cu(II) (X = AcO, n = 3), Pd(II) (X = Cl, n = 0) and UO 2(II) (X = NO 3, n = 0), and [Fe(L)Cl 2(H 2O)]·2H 2O. The molar conductance data reveal that the chelates are non-electrolytes. IR spectra show that the ligand is coordinated to the metal ions in a terdentate manner with ONN donor sites of the naphthyl OH, azo N and thiazole N. An octahedral structure is proposed for Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II) and UO 2(II) complexes and a square planar structure for Cu(II) and Pd(II) complexes. The thermal behaviour of these chelates shows that water molecules (coordinated and hydrated) and anions are removed in two successive steps followed immediately by decomposition of the ligand molecule in the subsequent steps. The relative thermal stability of the chelates is evaluated. The final decomposition products are found to be the corresponding metal oxides. The thermodynamic activation parameters, such as E*, Δ H*, Δ S* and Δ G* are calculated from the TG curves.

  12. A convenient method for determination of quizalofop-p-ethyl based on the fluorescence quenching of eosin Y in the presence of Pd(II)

    NASA Astrophysics Data System (ADS)

    Wu, Huan; Zhao, Yanmei; Tan, Xuanping; Zeng, Xiaoqing; Guo, Yuan; Yang, Jidong

    2017-03-01

    A convenient fluorescence quenching method for determination of Quizalofop-p-ethyl(Qpe) was proposed in this paper. Eosin Y(EY) is a red dye with strong green fluorescence (λex/λem = 519/540 nm). The interaction between EY, Pd(II) and Qpe was investigated by fluorescence spectroscopy, resonance Rayleigh scattering(RRS) and UV-Vis absorption. Based on changes in spectrum, Pd(II) associated with Qpe giving a positively charged chelate firstly, then reacted with EY through electrostatic and hydrophobic interaction formed ternary chelate could be demonstrated. Under optimum conditions, the fluorescence intensity of EY could be quenched by Qpe in the presence of Pd(II) and the RRS intensity had a remarkable enhancement, which was directly proportional to the Qpe concentration within a certain concentration range, respectively. Based on the fluorescence quenching of EY-Pd(II) system by Qpe, a novel, convenient and specific method for Qpe determination was developed. To our knowledge, this is the first fluorescence method for determination of Qpe was reported. The detection limit for Qpe was 20.3 ng/mL and the quantitative determination range was 0.04-1.0 μg/mL. The method was highly sensitive and had larger detection range compared to other methods. The influence of coexisting substances was investigated with good anti-interference ability. The new analytical method has been applied to determine of Qpe in real samples with satisfactory results.

  13. Use of microorganisms immobilized on composite polyurethane foam to remove Cu(II) from aqueous solution.

    PubMed

    Zhou, Lin-Cheng; Li, Yan-Feng; Bai, Xue; Zhao, Guang-Hui

    2009-08-15

    Composite polyurethane (PU) foams were made via the polymerization of toluene diisocyanate (TDI) and polyether polyol with activated carbon fiber, and immobilized microorganisms on polyurethane (IPU) foam were prepared by cultivating the microbe B350 in a mixture of culture medium and PU. We used batch adsorption techniques to study the removal of Cu(II) ions from aqueous solutions via PU and IPU. Moreover, the effects of pH, temperature, carrier amount, and biosorption time on the removal rate of Cu(II), adsorption equilibrium, and adsorption kinetics were investigated in detail. The IPU showed an excellent removal rate for Cu(II). The adsorption kinetics data were in good agreement with the pseudo-second-order rate model, and the adsorption isotherms could be adequately described by the Langmuir equation. For synthetic wastewater containing Cu(II), the removal rates for Cu(II) and COD after 4h treatment were 85% and 80%, respectively.

  14. Highly efficient simultaneous ultrasonic-assisted adsorption of Pb(II), Cd(II), Ni(II) and Cu (II) ions from aqueous solutions by graphene oxide modified with 2,2'-dipyridylamine: Central composite design optimization.

    PubMed

    Zare-Dorabei, Rouholah; Ferdowsi, Somayeh Moazen; Barzin, Ahmad; Tadjarodi, Azadeh

    2016-09-01

    In present work, a graphene oxide chemically modified with 2,2'-dipyridylamine (GO-DPA), was synthesized by simple, fast and low-cost process for the simultaneous adsorption of four toxic heavy metals, Pb(II), Cd(II), Ni(II) and Cu(II), from aqueous solutions. The synthesized adsorbent was characterized by FT-IR, XRD, XPS, SEM and AFM measurements. The effects of variables such as pH solution, initial ion concentrations, adsorbent dosage and sonicating time were investigated on adsorption efficiency by rotatable central composite design. The optimum conditions, specified as 8mg of adsorbent, 20mgL(-1) of each ion at pH 5 and short time of 4min led to the achievement of a high adsorption capacities. Ultrasonic power had important role in shortening the adsorption time of ions by enhancing the dispersion of adsorbent in solution. The adsorption kinetic studies and equilibrium isotherms for evaluating the mechanism of adsorption process showed a good fit to the pseudo-second order and Langmuir model, respectively. The maximum adsorption capacities (Qm) of this adsorbent were 369.749, 257.201, 180.893 and 358.824mgg(-1) for lead, cadmium, nickel and copper ions, respectively. The removal performance of adsorbent on the real wastewater samples also showed the feasibility of adsorbent for applying in industrial purposes.

  15. Molecular-programmed self-assembly of homo- and heterometallic penta- and hexanuclear coordination compounds: synthesis, crystal structures, and magnetic properties of ladder-type CuII2MIIx (M=Cu, Ni; x=3, 4) oxamato complexes with CuII2 metallacyclophane cores.

    PubMed

    Pardo, Emilio; Ruiz-García, Rafael; Lloret, Francesc; Julve, Miguel; Cano, Joan; Pasán, Jorge; Ruiz-Pérez, Catalina; Filali, Yasmine; Chamoreau, Lise-Marie; Journaux, Yves

    2007-05-28

    New homo- and heterometallic, hexa- and pentanuclear complexes of formula {[Cu2(mpba)2(H2O)F][Cu(Me5dien)]4}(PF6)(3).5H2O (1), {[Cu2(Me3mpba)2(H2O)2][Cu(Me5dien)]4}(ClO4)(4).12H2O (2), {[Cu2(ppba)2][Cu(Me5dien)]4}(ClO4)4 (3), and [Ni(cyclam)]{[Cu2(mpba)2][Ni(cyclam)]3}(ClO4)(4).6H2O (4) [mpba=1,3-phenylenebis(oxamate), Me3mpba=2,4,6-trimethyl-1,3-phenylenebis(oxamate), ppba=1,4-phenylenebis(oxamate), Me5dien=N,N,N'N' ',N' '-pentamethyldiethylenetriamine, and cyclam=1,4,8,11-tetraazacyclotetradecane] have been synthesized through the use of the "complex-as-ligand/complex-as-metal" strategy. The structures of 1-3 consist of cationic CuII6 entities with an overall [2x2] ladder-type architecture which is made up of two oxamato-bridged CuII3 linear units connected through two m- or p-phenylenediamidate bridges between the two central copper atoms to give a binuclear metallacyclic core of the cyclophane-type. Complex 4 consists of cationic CuII2NiII3 entities with an incomplete [2x2] ladder-type architecture which is made up of oxamato-bridged CuIINiII and CuIINiII2 linear units connected through two m-phenylenediamidate bridges between the two copper atoms to give a binuclear metallacyclophane core. The magnetic properties of 1-3 and 4 have been interpreted according to their distinct "dimer-of-trimers" and "dimer-plus-trimer" structures, respectively, (H=-J(S1A.S3A+S1A.S4A+S2B.S5B+S2B.S6B)-J'S1A.S2B). Complexes 1-4 exhibit moderate to strong antiferromagnetic coupling through the oxamate bridges (-JCu-Cu=81.3-105.9 cm-1; -JCu-Ni=111.6 cm-1) in the trinuclear and/or binuclear units. Within the binuclear metallacyclophane core, a weak to moderate ferromagnetic coupling (J'Cu-Cu=1.7-9.0 cm-1) operates through the double m-phenylenediamidate bridge, while a strong antiferromagnetic coupling (J'Cu-Cu=-120.6 cm-1) is mediated by the double p-phenylenediamidate bridge.

  16. Apo-neocarzinostatin: a protein carrier for Cu(II) glycocomplexes and Cu(II) into U937 and HT29 cell lines.

    PubMed

    Garcia, Ludivine; Franzoni, Susanna; Mussi, Francesca; Aumont-Niçaise, Magali; Bertrand, Hélène; Desmadril, Michel; Pelosi, Giorgio; Buschini, Annamaria; Policar, Clotilde

    2014-06-01

    In the field of pharmaceuticals there is an increasing need for new delivery systems to overcome the issues of solubility, penetration, toxicity and drug resistance. One of the possible strategies is to use biocarriers such as proteins to encourage the cell-penetration of drugs. In this paper, the use of the apo-protein neocarzinostatin (apo-NCS) as a carrier-protein for two Cu(II) glycocomplexes, previously characterized, and Cu(II) ions was investigated. Its interaction with the metallic compounds was analyzed using microcalorimetry. The dissociation constants were shown to be in the micromolar range. The Cu(II) glycocomplexes, in absence of apo-NCS, were found to be cytotoxic in the U937 and HT29 cell lines whereas the corresponding glycoligands showed no toxicity. The leukemic cell line (U937) seems to be more sensitive to glycocomplexes than the colon cancer cell line (HT29). Interestingly, apo-NCS was shown to increase systematically the antiproliferative activity by a factor of 2 and 3 for Cu(II) glycocomplexes and Cu(II) respectively. The antiproliferative activity detected was not related to proteasome inhibition. This result stresses the importance of new molecular tools for the delivery of Cu(II) to tumor cells using non-covalent association with carriers proteins.

  17. Nano sponge Mn₂O ₃ as a new adsorbent for the preconcentration of Pd(II) and Rh(III) ions in sea water, wastewater, rock, street sediment and catalytic converter samples prior to FAAS determinations.

    PubMed

    Yavuz, Emre; Tokalıoğlu, Serife; Sahan, Halil; Patat, Saban

    2014-10-01

    In this study, a nano sponge Mn2O3 adsorbent was synthesized and was used for the first time. Various parameters affecting the recovery values of Pd(II) and Rh(III) were examined. The tolerance limits (≥ 90 %) for both Pd(II) and Rh(III) ions were found to be 75,000 mg L(-1) Na(I), 75,000 mg L(-1) K(I), 50,000 mg L(-1) Mg(II) and 50,000 mg L(-1) Ca(II). A 30s contact time was enough for both adsorption and elution. A preconcentration factor of 100 was obtained by using 100mg of the nano sponge Mn2O3. The reusability of the adsorbent was 120 times. Adsorption capacities for Pd(II) and Rh(III) were found to be 42 and 6.2 mg g(-1), respectively. The detection limits were 1.0 µg L(-1) for Pd(II) and 0.37 µg L(-1) for Rh(III) and the relative standard deviations (RSD, %) were found to be ≤ 2.5%. The method was validated by analyzing the standard reference material, SRM 2556 (Used Auto Catalyst Pellets) and spiked real samples. The optimized method was applied for the preconcentration of Pd(II) and Rh(III) ions in water (sea water and wastewater), rock, street sediment and catalytic converter samples.

  18. Saturation magnetization of Ni(II) in metalloproteins and model compounds

    SciTech Connect

    Sendova, M.; Day, E.P.; Kiick, K.; Johnson, M.; Ma, L.; Scott, B.; Hausinger, R.; Todd, M.; Peterson, J. Univ. of Georgia, Athens Michigan State Univ., East Lansing Univ. of Alabama, Tuscaloosa )

    1992-01-01

    The Ni(II) sites of urease (from Klebsiella aerogenes and jack bean), coenzyme F[sub 430] (from Methanobacterium thermoautotrophicum), and several model compounds having octahedral symmetry have been studied using the saturation megnetization technique. Data were collected at four fixed fields over the temperature range from 2 - 200K. Theoretical curves calculated from the spin Hamiltonian were used to fit the experimentally obtained magnetization curves. The following parameters were determined: the spine state (S), the amount of the sample in this spin state ([S]), the gyromagnetic ratio (g), and the zero field splitting parameters (D, E/D). The amount of S=1 paramagnetism of the Ni(II) sites was found to depend on the pH of the buffer and on the concentration of the protein in D[sub 2]O (for coenzyme F[sub 430]). The relationship of the strength of the ligand field to the zero field splitting parameter was studied for the model compounds. There was no evidence for exchange coupling between the two Ni(II) ions at the active sites of either plant or bacterial urease.

  19. A Trinuclear Ni(II) Enediolate Complex: Synthesis, Characterization, and O2 Reactivity

    PubMed Central

    Arif, Atta M.; Berreau, Lisa M.

    2009-01-01

    Using a new N4-donor chelate ligand having a mixture of hydrophobic phenyl and hydrogen bond donor appendages, a trinuclear Ni(II) complex of the doubly deprotonated form of 2-hydroxy-1,3-diphenylpropane-1,3-dione was isolated, characterized (X-ray crystallography, elemental analysis, UV-vis, 1H NMR, FTIR, magnetic moment measurement), and evaluated for O2 reactivity. This complex, [(6-NA-6-Ph2TPANi)2(μ-PhC(O)C(O)C(O)Ph)2Ni](ClO4)2 (4), has two terminal pseudo octahedral Ni(II) centers supported by the tetradentate chelate ligand, and a central square planar Ni(II) ion ligated by oxygen atoms of two bridging enediolate ligands. In CH3CN, 4 exhibits a deep orange/brown color and λmax = 463 nm (ε = 16,000 M-1cm-1). The room temperature magnetic moment of 4, determined by Evans method, is μeff = 5.3(2) μB. This is consistent with the presence of two non-interacting high-spin Ni(II) centers, a diamagnetic central Ni(II) ion, and an overall quintet ground state. Exposure of a CH3CN solution of 4 to O2 results in the rapid loss of the orange/brown color to give a green solution. The products identified from this reaction are [(κ3-6-NA-6-Ph2TPA)Ni(O2Ph)(H2O)]ClO4 (5), benzil (PhC(O)C(O)Ph), and CO. Identification of 5 was achieved via its independent synthesis and comparison of its 1H NMR and mass spectral features with those of the 6-NA-6-Ph2TPA-containing product generated upon reaction of 4 with O2. The independently prepared sample of 5 was characterized by X-ray crystallography, elemental analysis, UV-vis, mass spectrometry, and FTIR. The O2 reactivity of 4 has relevance to the active site chemistry of Ni(II)-containing acireductone dioxygenase (Ni(II)-ARD). PMID:18959363

  20. Process optimization for Ni(II) removal from wastewater by calcined oyster shell powders using Taguchi method.

    PubMed

    Yen, Hsing Yuan; Li, Jun Yan

    2015-09-15

    Waste oyster shells cause great environmental concerns and nickel is a harmful heavy metal. Therefore, we applied the Taguchi method to take care of both issues by optimizing the controllable factors for Ni(II) removal by calcined oyster shell powders (OSP), including the pH (P), OSP calcined temperature (T), Ni(II) concentration (C), OSP dose (D), and contact time (t). The results show that their percentage contribution in descending order is P (64.3%) > T (18.9%) > C (8.8%) > D (5.1%) > t (1.7%). The optimum condition is pH of 10 and OSP calcined temperature of 900 °C. Under the optimum condition, the Ni(II) can be removed almost completely; the higher the pH, the more the precipitation; the higher the calcined temperature, the more the adsorption. The latter is due to the large number of porosities created at the calcination temperature of 900 °C. The porosities generate a large amount of cavities which significantly increase the surface area for adsorption. A multiple linear regression equation obtained to correlate Ni(II) removal with the controllable factors is: Ni(II) removal(%) = 10.35 × P + 0.045 × T - 1.29 × C + 19.33 × D + 0.09 × t - 59.83. This equation predicts Ni(II) removal well and can be used for estimating Ni(II) removal during the design stage of Ni(II) removal by calcined OSP. Thus, OSP can be used to remove nickel effectively and the formula for removal prediction is developed for practical applications.

  1. Sorption of Cu(II) complexes with ligands tartrate, glycine and quadrol by chitosan.

    PubMed

    Gyliene, Ona; Binkiene, Rima; Butkiene, Rita

    2009-11-15

    The sorption by chitosan in Cu(II) solutions containing tartrate, glycine (amino acetic acid) and quadrol (N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine) as ligands has been investigated. The degree of sorbate removal strongly depends on pH. In solutions containing tartrate almost complete sorption of both Cu(II) and tartrate proceeds in mildly acidic and neutral solutions. The sorption of Cu(II) is also complete in alkaline solutions containing glycine; meanwhile a substantial sorption of glycine proceeds at pH approximately 6. The Cu(II) sorption in solutions containing quadrol is insignificant. Any sorption of quadrol does not proceed in the whole range of pH investigated. The investigations under equilibrium conditions showed that the Cu(II) sorption from tartrate containing solutions obeys Freundlich equation and in solutions containing glycine and quadrol it fits Langmuir equation. Supposedly, Cu(II) sorption onto chitosan proceeds with formation of amino complexes onto the surface of chitosan; the sorption of tartrate proceeds as electrostatic as well as with formation of amide bonds. Applying of electrolysis enables a complete removal of sorbed Cu(II) and ligands without changes in physical and chemical properties of chitosan. This is confirmed by sorption ability of regenerated chitosan, measurements of its molecular weight, the deacetylation degree and FT-IR spectra.

  2. Design, properties and application of a facile fluorescence switch for Cu(II)

    NASA Astrophysics Data System (ADS)

    Diao, Haipeng; Niu, Weiping; Liu, Wen; Feng, Liheng; Xie, Jun

    2017-01-01

    A facile fluorescence switch based on Schiff base 2,2‧-[1,3-phenylenbis- (methylidynenitrilo)]bis[benzenethiol] (PMBB) has been developed and used to sensing metal ions. UV-vis absorption and fluorescence emission spectra show that the PMBB receptor has high selectivity and sensitivity for Cu(II) ions. Based on the photoinduced electron transfer (PET) and chelation enhanced fluorescence (CHEF) mechanisms, the receptor exhibits an fluorescence "turn-on" switch signal for Cu(II). The 1:1 binding mode of PMBB and Cu (II) ions can be obtained by the Job-plot and ESI-Mass spectra data. Noticeably, the color changes (from colorless to yellow) of PMBB solutions for Cu(II) sensing can be observed by naked eyes in the sunlight. The detection limit of the receptor for Cu(II) may reach 10- 7 mol/L with a good linear relation in the lower concentrations of Cu(II). To develop the practical application, the Cu(II) ions in swimming pool water samples were detected. Results show that PMBB receptor as a fluorescent probe can use to detect the trace level of Cu(II) in the environmental samples. This work contributes to providing a facile strategy for designing efficient probes and developing their practical application value.

  3. The influence of Cu(II) on the decay of monochloramine.

    PubMed

    Fu, Jun; Qu, Jiuhui; Liu, Ruiping; Zhao, Xu; Qiang, Zhimin

    2009-01-01

    Maintenance of monochloramine concentration during water disinfection is important to ensure the microbial safety of drinking water. The decay of monochloramine always occurs and some substances present in the water can accelerate this process. Copper often exists in ionic form in water, but the effect of Cu(II) on the decomposition of monochloramine is largely unknown. In this paper, a series of experiments were carried out under varying conditions of pH, Cu(II) and initial monochloramine concentrations. Results showed that the decomposition rate of monochloramine was greatly enhanced by Cu(II), and this enhancement decreased with the increase of solution pH and the decrease of Cu(II) concentration. It was proposed that the monochloramine decomposition in the presence of Cu(II) was catalyzed via complexation between Cu(II) and monochloramine. The X-ray absorption fine structure experiments gave further evidence to this conclusion. The results will provide useful information for selecting proper disinfection method in water disinfection where Cu(II) exists and reasonable monochloramine dosage during chloramination.

  4. The aerobic oxidation of a Pd(II) dimethyl complex leads to selective ethane elimination from a Pd(III) intermediate.

    PubMed

    Khusnutdinova, Julia R; Rath, Nigam P; Mirica, Liviu M

    2012-02-01

    Oxidation of the Pd(II) complex (N4)Pd(II)Me(2) (N4 = N,N'-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane) with O(2) or ROOH (R = H, tert-butyl, cumyl) produces the Pd(III) species [(N4)Pd(III)Me(2)](+), followed by selective formation of ethane and the monomethyl complex (N4)Pd(II)Me(OH). Cyclic voltammetry studies and use of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap suggest an inner-sphere mechanism for (N4)Pd(II)Me(2) oxidation by O(2) to generate a Pd(III)-superoxide intermediate. In addition, reaction of (N4)Pd(II)Me(2) with cumene hydroperoxide involves a heterolytic O-O bond cleavage, implying a two-electron oxidation of the Pd(II) precursor and formation of a transient Pd(IV) intermediate. Mechanistic studies of the C-C bond formation steps and crossover experiments are consistent with a nonradical mechanism that involves methyl group transfer and transient formation of a Pd(IV) species. Moreover, the (N4)Pd(II)Me(OH) complex formed upon ethane elimination reacts with weakly acidic C-H bonds of acetone and terminal alkynes, leading to formation of a new Pd(II)-C bond. Overall, this study represents the first example of C-C bond formation upon aerobic oxidation of a Pd(II) dimethyl complex, with implications in the development of Pd catalysts for aerobic oxidative coupling of C-H bonds.

  5. Construction of new biopolymer (chitosan)-based pincer-type Pd(II) complex and its catalytic application in Suzuki cross coupling reactions

    NASA Astrophysics Data System (ADS)

    Baran, Talat; Menteş, Ayfer

    2017-04-01

    In this paper we described the fabrication, characterization and application of a new biopolymer (chitosan)-based pincer-type Pd(II) catalyst in Suzuki cross coupling reactions using a non-toxic, cheap, eco-friendly and practical method. The catalytic activity tests showed remarkable product yields as well as TON (19800) and TOF (330000) values with a small catalyst loading. In addition, the catalyst indicated good recyclability in the Suzuki C-C reaction. This biopolymer supported catalyst can be used with various catalyst systems due to its unique properties, such as being inert, green in nature, low cost and chemically durable.

  6. Synthesis, spectroscopic, thermal and anticancer studies of metal-antibiotic chelations: Ca(II), Fe(III), Pd(II) and Au(III) chloramphenicol complexes

    NASA Astrophysics Data System (ADS)

    Al-Khodir, Fatima A. I.; Refat, Moamen S.

    2016-09-01

    Four Ca(II), Fe(III), Pd(II) and Au(III) complexes of chloramphenicol drug have been synthesized and well characterized using elemental analyses, (infrared, electronic, and 1H-NMR) spectra, magnetic susceptibility measurement, and thermal analyses. Infrared spectral data show that the chloramphenicol drug coordinated to Ca(II), Pd(II) and Au(III) metal ions through two hydroxyl groups with 1:1 or 1:2 M ratios, but Fe(III) ions chelated towards chloramphenicol drug via the oxygen and nitrogen atoms of amide group with 1:2 ratio based on presence of keto↔enol form. The X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques were used to identify the nano-size particles of both iron(III) and gold(III) chloramphenicol complexes. The antimicrobial assessments of the chloramphenicol complexes were scanned and collected the results against of some kind of bacteria and fungi. The cytotoxic activity of the gold(III) complex was tested against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.

  7. Characterizing Ni(II) hydration in aqueous solution using DFT and EXAFS.

    PubMed

    Liu, H Y; Fang, C H; Fang, Y; Zhou, Y Q; Ge, H W; Zhu, F Y; Sun, P C; Miao, J T

    2016-01-01

    In the present work, a detailed investigation of Ni(II) hydration in water solutions was carried out using density functional theory (DFT) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The hydrated characteristics of [Ni(H2O)n](2+) clusters, such as energy parameters, atomic charge distributions, and bond parameters, were explored using DFT with Becke's three-parameter exchange potential and the Lee-Yang-Parr correlation functional (B3LYP). DFT calculations indicated that the preferred structure of the first hydration shell of Ni(II) generally has a coordination number of six and is almost unaffected by the water molecules in the outer solvation shell, whereas the structure of the second solvation shell varies as the hydration proceeds. EXAFS measurements are reported for aqueous NiSO4 and Ni(NO3)2 solutions and the Ni(NO3)2·6H2O crystal. Analysis of the EXAFS spectra of these three systems using a multiparameter fitting procedure showed that, in each case, the first coordination shell consists of six water molecules with a Ni-O coordination distance of 2.04 Å, and that there is no Ni-S or Ni-N coordination in the first shell. There was no evidence of outer-shell SO4(2-) or NO3(-) ions substituting inner-sphere water molecules in NiSO4 and Ni(NO3)2. The characteristics of Ni(II) hydration obtained from DFT calculations agreed well with those obtained experimentally using EXAFS.

  8. XAFS study of bioactive Cu(II) complexes of 7-hydroxycoumarin derivatives in organic solvents

    NASA Astrophysics Data System (ADS)

    Klepka, M. T.; Wolska, A.; Drzewiecka-Antonik, A.; Rejmak, P.; Hatada, K.; Aquilanti, G.

    2017-04-01

    We characterize the structure of two Cu(II) complexes of 7-hydroxycoumarins in organic solvents. The solvents are, dimethyl sulfoxide and dimethylformamide. X-ray absorption spectroscopy together with density functional theory calculations are employed to identify the structural changes induced by the two solvents in comparison to the solid form of complexes. We show that the structure of the Cu(II) complexes is modified depending on the solvent and we propose the geometry of the complexes molecule.

  9. Is there a redox reaction between Cu(II) and gallic acid?

    PubMed

    Severino, Joyce Ferreira; Goodman, Bernard A; Reichenauer, Thomas G; Pirker, Katharina F

    2011-02-01

    Interactions between transition metal ions and polyphenols can result in complexation, redox or polymerization, but the relative importance of these reactions is unclear. The present paper reports results from the reaction of gallic acid (GA) with Cu(II) using electron paramagnetic resonance (EPR) and UV/visible spectroscopy for various relative concentrations and pH values. Reduction of Cu(II) by GA does not occur under strongly acidic or strongly alkaline conditions. Di- or polymerization reactions between Cu(II) and carboxylate groups of GA dominate the results at acidic pH, whereas mononuclear complexes increase in importance at higher pH and GA concentrations. There was no evidence for any redox reaction between Cu(II) and GA and free radical formation from GA at high pH was shown to be the consequence of auto-oxidation, which was inhibited by Cu(II). Serious questions are thus raised about the existence of the frequently assumed redox reactions between Cu(II) and polyphenols.

  10. An omp gene enhances cell tolerance of Cu(II) in Sinorhizobium meliloti CCNWSX0020.

    PubMed

    Li, Zhefei; Lu, Mingmei; Wei, Gehong

    2013-09-01

    The main aim of this work was to study molecular characterization of a DNA fragment conferring resistance to Cu(II) in Sinorhizobium meliloti CCNWSX0020. The strain CCNWSX0020, resistant to 1.4 mmol l(-1) Cu(II) in tryptone-yeast extract medium was isolated from Medicago lupulina growing in mine tailings of Fengxian County, China. The availability of the complete genome sequence of S. meliloti CCNWSX0020 provides an opportunity for investigating genes that play significant roles in Cu(II) resistance. A copper resistance gene, with a length of 1,445 bp, encoding 481 amino acids, designated omp, was identified by cDNA-amplified fragment length polymorphism from S. meliloti CCNWSX0020. The expression of omp gene strongly increased in the presence of Cu(II). The omp-defective mutants display sensitivities to Cu(II) compared with their wild types. The Cu(II)-sensitive phenotype of the mutant was complemented by a 1.5-kb DNA fragment containing omp gene. BLAST analysis revealed that this gene encoded a hypothetical outer membrane protein with 75 % similarity to outer membrane efflux protein in Rhizobium leguminosarum bv. viciae 3841. These studies suggested that the omp product was involved in the Cu(II) tolerance of S. meliloti CCNWSX0020.

  11. Anticandidal activity of cinnamaldehyde, its ligand and Ni(II) complex: effect of increase in ring and side chain.

    PubMed

    Shreaz, Sheikh; Sheikh, Rayees A; Rimple, Bhatia; Hashmi, Athar Adil; Nikhat, Manzoor; Khan, Luqman A

    2010-09-01

    To increase efficacy of cinnamaldehyde as an antimycotic agent, N, N'- Bis (trans-cinnamadehyde) ethylenediimine [C(20)H(20)N(2)] and Ni(II) complex of the type [Ni(C(40)H(40)N(4))Cl(2)] have been synthesized. The ligand [P] and Ni(II) complex have been characterized on the basis of elemental analysis, FTIR, ESI- MS, IR, (1)H NMR, UV-Vis spectroscopic techniques, conductivity and magnetic measurements. MIC of cinnamaldehyde against clinical isolate of Candida albicans and Candida tropicalis was 400 microg/ml and 500 microg/ml, respectively. Synthesized ligand has markedly reduced MIC; 200 microg/ml and 300 microg/ml whereas Ni(II) complex of ligand displayed MIC of 90 microg/ml and 120 microg/ml. Growth and sensitivity of the organisms were effected by ligand & complex at significantly reduced concentration. Plasma membrane ATPase activity and ergosterol content have been investigated as site of action. Result obtained indicates ergosterol biosynthesis pathway as site of action of cinnamaldehyde, synthesized ligand and its Ni(II) complex.

  12. Direct functionalization of M-C (M = Pt(II), Pd(II)) bonds using environmentally benign oxidants, O2 and H2O2.

    PubMed

    Vedernikov, Andrei N

    2012-06-19

    Atom economy and the use of "green" reagents in organic oxidation, including oxidation of hydrocarbons, remain challenges for organic synthesis. Solutions to this problem would lead to a more sustainable economy because of improved access to energy resources such as natural gas. Although natural gas is still abundant, about a third of methane extracted in distant oil fields currently cannot be used as a chemical feedstock because of a dearth of economically and ecologically viable methodologies for partial methane oxidation. Two readily available "atom-economical" "green" oxidants are dioxygen and hydrogen peroxide, but few methodologies have utilized these oxidants effectively in selective organic transformations. Hydrocarbon oxidation and C-H functionalization reactions rely on Pd(II) and Pt(II) complexes. These reagents have practical advantages because they can tolerate moisture and atmospheric oxygen. But this tolerance for atmospheric oxygen also makes it challenging to develop novel organometallic palladium and platinum-catalyzed C-H oxidation reactions utilizing O(2) or H(2)O(2). This Account focuses on these challenges: the development of M-C bond (M = Pt(II), Pd(II)) functionalization and related selective hydrocarbon C-H oxidations with O(2) or H(2)O(2). Reactions discussed in this Account do not involve mediators, since the latter can impart low reaction selectivity and catalyst instability. As an efficient solution to the problem of direct M-C oxidation and functionalization with O(2) and H(2)O(2), this Account introduces the use of facially chelating semilabile ligands such as di(2-pyridyl)methanesulfonate and the hydrated form of di(2-pyridyl)ketone that enable selective and facile M(II)-C(sp(n)) bond functionalization with O(2) (M = Pt, n = 3; M = Pd, n = 3 (benzylic)) or H(2)O(2) (M = Pd, n = 2). The reactions proceed efficiently in protic solvents such as water, methanol, or acetic acid. With the exception of benzylic Pd(II) complexes, the

  13. Cu(II) and Zn(II) adsorption capacity of three different clay liner materials.

    PubMed

    Musso, T B; Parolo, M E; Pettinari, G; Francisca, F M

    2014-12-15

    Sorption of Cu(II) and Zn(II) on three natural clays meeting the international requirements for use as liners was evaluated by means of batch tests. The purpose of this research was to determine the retention capacities of the clays for metal cations commonly present in urban solid waste leachates. The pH and ionic strength conditions were set at values frequently found in real leachates. The changes observed in the XRD patterns and FTIR spectra upon adsorption can be considered an evidence of clay-metal electrostatic interaction. The Langmuir model was found to best describe the sorption processes, offering maximum sorption capacities from 8.16 to 56.89 mg/g for Cu(II) and from 49.59 to 103.83 mg/g for Zn(II). All samples remove more Zn(II) than Cu(II), which may be related to the different geometry of the hydrated Cu(II) cation. The total amount of metal sorption was strongly influenced by the total specific surface area, the presence of carbonates and the smectite content of the clays. In addition to their known quality as physical barriers, the adsorbed amounts obtained indicate the suitability of the tested clays to contribute to the retardation of Cu(II) and Zn(II) transport through clay liners.

  14. Optimization of Cu(II) biosorption onto Ascophyllum nodosum by factorial design methodology.

    PubMed

    Freitas, Olga; Delerue-Matos, Cristina; Boaventura, Rui

    2009-08-15

    A Box-Behnken factorial design coupled with surface response methodology was used to evaluate the effects of temperature, pH and initial concentration in the Cu(II) sorption process onto the marine macro-algae Ascophyllum nodosum. The effect of the operating variables on metal uptake capacity was studied in a batch system and a mathematical model showing the influence of each variable and their interactions was obtained. Study ranges were 10-40 degrees C for temperature, 3.0-5.0 for pH and 50-150 mg L(-1) for initial Cu(II) concentration. Within these ranges, the biosorption capacity is slightly dependent on temperature but markedly increases with pH and initial concentration of Cu(II). The uptake capacities predicted by the model are in good agreement with the experimental values. Maximum biosorption capacity of Cu(II) by A. nodosum is 70 mg g(-1) and corresponds to the following values of those variables: temperature=40 degrees C, pH=5.0 and initial Cu(II) concentration=150 mg L(-1).

  15. Characteristics and mechanisms of Cu(II) sorption from aqueous solution by using bioflocculant MBFR10543.

    PubMed

    Guo, Junyuan

    2015-01-01

    This paper investigated the characteristics of Cu(II) sorption from aqueous solution by using bioflocculant MBFR10543 and discussed the mechanism during the sorption process. Results have demonstrated that the removal efficiency of Cu(II) reached 96.9% by adding MBFR10543 in two stages, separately, 1.5 × 10(-2) % (w/w) in the 1.0-min rapid mixing (180 rpm) and 2.0 × 10(-2) % (w/w) after 2.0-min slow mixing (80 rpm), with pH value fixed at 6.0. Cu(II) sorption process could be described by the pseudo-second-order kinetic model and the Langmuir isotherms model. The negative Gibbs free energy change indicated the spontaneous nature of the sorption. Fourier transform infrared spectra analysis indicated that functional groups, such as -OH, -COOH, C═O, and -NH2, were existed in MBFR10543 molecular chains, which had strong capacity for removing Cu(II). Furthermore, both charge neutralization and bridging being the main mechanisms involved in Cu(II) removal by MBFR10543.

  16. Removal of heavy metal Cu(II) in simulated aquaculture wastewater by modified palygorskite.

    PubMed

    Cao, Jia-Shun; Wang, Cheng; Fang, Fang; Lin, Jun-Xiong

    2016-12-01

    Palygorskite (PAL) is a good heavy metal adsorbent due to its high surface area, low cost, and environmentally compatibility. But the natural PAL has limited its adsorption capacity and selectivity. In this study, a cost-effective and readily-generated absorbent, l-threonine-modified palygorskite (L-PAL), was used and its performance for Cu(II) removal in simulated aquaculture wastewater was evaluated. After preparation, L-PAL was characterized by using Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric analysis. The impacts of pH, adsorbent dosage, contact time, and initial Cu(II) concentration on the adsorption capacity of L-PAL were examined. The Cu(II) adsorption capacity on L-PAL was enhanced almost 10 times than that of raw PAL. The adsorption isotherms of Cu(II) fit the Langmuir isotherms, and the adsorption kinetics was dominated by the pseudo-second-order model. The thermodynamic parameters at four temperatures were calculated, which indicated that the adsorption was spontaneous and endothermic. The adsorption mechanism involves complexation, chelation, electrostatic attraction, and micro-precipitation. Furthermore, L-PAL is shown to have a high regeneration capacity. These results indicate that L-PAL is a cheap and promising absorbent for Cu(II) removal and hold potential to be used for aquaculture wastewater treatment.

  17. Exploiting orientation-selective DEER: determining molecular structure in systems containing Cu(ii) centres.

    PubMed

    Bowen, Alice M; Jones, Michael W; Lovett, Janet E; Gaule, Thembanikosi G; McPherson, Michael J; Dilworth, Jonathan R; Timmel, Christiane R; Harmer, Jeffrey R

    2016-02-17

    Orientation-selective DEER (Double Electron-Electron Resonance) measurements were conducted on a series of rigid and flexible molecules containing Cu(ii) ions. A system with two rigidly held Cu(ii) ions was afforded by the protein homo-dimer of copper amine oxidase from Arthrobacter globiformis. This system provided experimental DEER data between two Cu(ii) ions with a well-defined distance and relative orientation to assess the accuracy of the methodology. Evaluation of orientation-selective DEER (os DEER) on systems with limited flexibility was probed using a series of porphyrin-based Cu(ii)-nitroxide and Cu(ii)-Cu(ii) model systems of well-defined lengths synthesized for this project. Density functional theory was employed to generate molecular models of the conformers for each porphyrin-based Cu(ii) dimer studied. Excellent agreement was found between DEER traces simulated using these computed conformers and the experimental data. The performance of different parameterised structural models in simulating the experimental DEER data was also investigated. The results of this analysis demonstrate the degree to which the DEER data define the relative orientation of the two Cu(ii) ions and highlight the need to choose a parameterised model that captures the essential features of the flexibility (rotational freedom) of the system being studied.

  18. Rapid Photodegradation of Methyl Orange (MO) Assisted with Cu(II) and Tartaric Acid

    PubMed Central

    Guo, Jing; Chen, Xue; Shi, Ying; Lan, Yeqing; Qin, Chao

    2015-01-01

    Cu(II) and organic carboxylic acids, existing extensively in soil and aquatic environments, can form complexes that may play an important role in the photodegradation of organic contaminants. In this paper, the catalytic role of Cu(II) in the removal of methyl orange (MO) in the presence of tartaric acid with light was investigated through batch experiments. The results demonstrate that the introduction of Cu(II) could markedly enhance the photodegradation of MO. In addition, high initial concentrations of Cu(II) and tartaric acid benefited the decomposition of MO. The most rapid removal of MO assisted by Cu(II) was achieved at pH 3. The formation of Cu(II)-tartaric acid complexes was assumed to be the key factor, generating hydroxyl radicals (•OH) and other oxidizing free radicals under irradiation through a ligand-to-metal charge-transfer pathway that was responsible for the efficient degradation of MO. Some intermediates in the reaction system were also detected to support this reaction mechanism. PMID:26241043

  19. Influence of Cu(II) on the interaction of sulfite with DNA

    NASA Astrophysics Data System (ADS)

    Guo, Dong-Sheng; Yuan, Xiao-Ying; Liang, Jie-Qing

    2006-10-01

    The quantitative influence of Cu(II) on the interaction of eukaryotic DNA with sulfite (SO 32-), which is a derivative of sulfur dioxide in the human body, was studied using ultraviolet (UV) absorption spectrometry. The results showed that under physiological pH conditions, SO 32- reacted weakly with DNA at concentrations of up to 10 -1 M, at which point a rapid increase in the reaction constant and the reaction number of SO 32- with DNA was observed. The addition of Cu(II) at concentrations ranging from 6.67 × 10 -4 to 3.33 × 10 -3 M to DNA-SO 32- binary systems increased the reaction constant of SO 32- with DNA 41- to 115-fold at a low concentration of SO 32- (10 -3 M), and 4- to 84-fold at an intermediate concentration of SO 32- (10 -2 M), but had little influence on the reaction number of SO 32- with DNA compared with the absence of Cu(II). When the concentration of SO 32- reached 10 -1 M, the presence of Cu(II) reduced the reaction number but had no effect on the reaction constant of SO 32- with DNA. These results show that the efficiency of SO 32- is increased in the presence of Cu(II) at high concentrations of SO 32-.

  20. Rapid Photodegradation of Methyl Orange (MO) Assisted with Cu(II) and Tartaric Acid.

    PubMed

    Guo, Jing; Chen, Xue; Shi, Ying; Lan, Yeqing; Qin, Chao

    2015-01-01

    Cu(II) and organic carboxylic acids, existing extensively in soil and aquatic environments, can form complexes that may play an important role in the photodegradation of organic contaminants. In this paper, the catalytic role of Cu(II) in the removal of methyl orange (MO) in the presence of tartaric acid with light was investigated through batch experiments. The results demonstrate that the introduction of Cu(II) could markedly enhance the photodegradation of MO. In addition, high initial concentrations of Cu(II) and tartaric acid benefited the decomposition of MO. The most rapid removal of MO assisted by Cu(II) was achieved at pH 3. The formation of Cu(II)-tartaric acid complexes was assumed to be the key factor, generating hydroxyl radicals (•OH) and other oxidizing free radicals under irradiation through a ligand-to-metal charge-transfer pathway that was responsible for the efficient degradation of MO. Some intermediates in the reaction system were also detected to support this reaction mechanism.

  1. Constituting fully integrated visual analysis system for Cu(II) on TiO₂/cellulose paper.

    PubMed

    Li, Shun-Xing; Lin, Xiaofeng; Zheng, Feng-Ying; Liang, Wenjie; Zhong, Yanxue; Cai, Jiabai

    2014-07-15

    As a cheap and abundant porous material, cellulose filter paper was used to immobilize nano-TiO2 and denoted as TiO2/cellulose paper (TCP). With high adsorption capacity for Cu(II) (more than 1.65 mg), TCP was used as an adsorbent, photocatalyst, and colorimetric sensor at the same time. Under the optimum adsorption conditions, i.e., pH 6.5 and 25 °C, the adsorption ratio of Cu(II) was higher than 96.1%. Humic substances from the matrix could be enriched onto TCP but the interference of their colors on colorimetric detection could be eliminated by the photodegradation. In the presence of hydroxylamine, neocuproine, as a selective indicator, was added onto TCP, and a visual color change from white to orange was generated. The concentration of Cu(II) was quantified by the color intensity images using image processing software. This fully integrated visual analysis system was successfully applied for the detection of Cu(II) in 10.0 L of drinking water and seawater with a preconcentration factor of 10(4). The log-linear calibration curve for Cu(II) was in the range of 0.5-50.0 μg L(-1) with a determination coefficient (R(2)) of 0.985 and its detection limit was 0.073 μg L(-1).

  2. Spectroscopic, thermal characterization and cytotoxic activity of bi-, tri- and tetra-nuclear Pd(II) and Pt(II) complexes with diSchiff base ligands

    NASA Astrophysics Data System (ADS)

    Hegazy, Wael Hussein

    2014-10-01

    In this paper; new di-, tri-, and tetra-nuclear Pd(II) and Pt(II) complexes of N,N‧-bis(3,4-dihydroxybenzylidene)ethan-1,2-diamine (EDH4), N,N‧-bis(3,4-dihydroxy-benzylidene)-benzene-1,2-diamine (PDH4) and N,N‧-bis-(3,4-dihydroxybenzylidene)-4,5-dimethyl-1,2-diamine (MPDH4) ligands were synthesized by two different methods. The first method involve the synthesis of the three ligands from condensation reaction of 3,4-dihydroxybenzaldehyde (L‧H2) with ethylenediamine (en), o-phenylenediamine (o-PD), or 4,5-dimethyl-1,2-phenylendiamine (DMPD) in a mole ratio of 2:1 followed by the reaction of the resulting Schiff bases ligands with Pd(II) or Pt(II) ions in the presence of 2,2‧-dipyridyl (L) to form the di- and tri-nuclear metal complexes. The second method involve the condensation of the Pd complex LPd(II)L‧, (L = 2,2‧-dipyridyl, L‧ = 4-formylbenzene-1,2-bis(olate)) with en, o-PD, or DMPD in a mole ratio of 2:1, respectively, followed by reaction with PdCl2 to form di-, tri-, and tetra-nuclear palladium(II) complexes, respectively. Structures of ligands and metal complexes are characterized by physical properties, FT-IR spectra and nuclear magnetic resonance. The geometries of metal complexes are suggested according to elemental analysis, electronic absorption spectra, thermal analysis, atomic absorption, magnetic susceptibility and molar conductance. Cytotoxic activity against lung large cell carcinoma (H460), prostate carcinoma (DU145), breast adenocarcinoma (MCF-7), amelanotic melanoma (M-14), colon adenocarcinoma (HT-29), and chronic myelogenous leukemia (K562) is also reported.

  3. Determination of trace amounts of Pd(II) ions in water and road dust samples by flame atomic absorption spectrometry after preconcentration on modified organo nanoclay.

    PubMed

    Afzali, Daryoush; Mostafavi, Al; Afzali, Zahra

    2010-01-01

    This paper describes the application of organo nanoclay, an easily prepared and stable solid sorbent, to the preconcentration of trace amounts of palladium ions in aqueous solution. The organo nanoclay was prepared by adding tetradecyldimethylbenzylamonium chloride onto montmorillonite, which was then modified with 1-(2-pyridylazo)-2-naphthol. The modified nanoclay was used as a solid sorbent for separation and preconcentration of trace amounts of Pd(II) ions, and a simple, sensitive, and economical method was developed for determination of trace amounts of palladium by flame atomic absorption spectrometry. The sorption of Pd(II) ions was quantitative in the pH range of 1.5-5.0, whereas quantitative desorption occurred with 5.0 mL of a mixture containing 1.0 M thiourea and 1.0 M HCl. The RSD of the method was +/- 2.1% (n = 10; concn = 0.5 microg/mL), and the LOD (3sigma(bl); sigma = SD and bl = blank) was 0.1 ng/mL. The calibration curve was linear for concentrations of 0.5-8.0 microg/mL in the initial solution, and the preconcentration factor was 140. The maximum capacity of the sorbent was 2.4 mg Pd(II)/g modified organo nanoclay. The influences of the experimental parameters, including sample pH, eluant volume, eluant type, sample volume, and interfering ions, on the recoveries of the palladium ion were investigated. The proposed method was applied to the preconcentration and determination of palladium in different samples.

  4. XAFS and crystallographic studies of Ni(II) porphyrins in single crystals and in solution

    SciTech Connect

    Renner, M.W.; Furenlid, L.R.; Barkigia, K.M.; Fajer, J.

    1996-09-01

    Abstract. Nickel porphyrins serve as models for the active sites of several biological processes. Crystallographic and EXAFS results for a Ni meso-tetrapropyl porphyrin (NiTPrP) yield different Ni-N distances in solution and in the solid state. The Ni-N distances determined by single crystal polarized XAS and X-ray diffraction agree well. Polarized XANES experiments further establish that the pre-edge feature observed in square planar Ni(II) complexes is a ls-4pz transition. The single crystal and solution EXAFS results demonstrate that conformational variations of the porphyrin macrocycle can readily be imposed by environmental and/or packing forces and can thereby modulate the chemical and physical properties of porphyrinic chromophores and prosthetic groups.

  5. Rapid and direct electrochemical determination of Ni(II) in industrial discharge water.

    PubMed

    Ferancová, Adriana; Hattuniemi, Maarit K; Sesay, Adama M; Räty, Jarkko P; Virtanen, Vesa T

    2016-04-05

    Industrial water contains a number of contaminants, such as organic pollutants and heavy metals, which can significantly affect the quality of soil, ground and environmental waters. We have successfully optimized and tested an electrochemical method and sensor modified with dimethylglyoxime for monitoring of nickel(II). The detection limit was 0.03mg/L and determination limit was 0.09mg/L. Linear concentration range was observed from 0.06 to 0.5mg/L Ni(II) and it is suitable for the analysis of environmental waters. The effect of all parameters important for on-site measurements (such as interferences, presence of dissolved oxygen, temperature) was investigated and considered in the analysis of mine discharge water. Water samples were analyzed without any pretreatment or filtration. A low level of error (5.6%) was observed for analysis demonstrating the usability of the optimized sensor and method for on-site measurements.

  6. Dynamic self-assembly of an M3L6 molecular triangle and an M4L8 tetrahedron from naked Pd(II) ions and bis(3-pyridyl)-substituted arenes.

    PubMed

    Chand, Dillip K; Biradha, Kumar; Kawano, Masaki; Sakamoto, Shigeru; Yamaguchi, Kentaro; Fujita, Makoto

    2006-07-17

    The pyridine-appended nonchelating bidentate ligands 1,4-bis(3-pyridyl)benzene (1) and 4,4'-bis(3-pyridyl) biphenyl (2) were complexed with a naked Pd(II) ion for the construction of molecular cage compounds. Prior to these experiments, the complexation of the ligands with cis-[Pd(en)(NO3)2] was also examined, because self-assemblies from the cis-protected Pd(II) ion were expected to be simple motifs that constitute the assemblies from naked Pd(II) ion. The structures of the self-assembled compounds resulting from 1 and [Pd(en)(NO3)2] depended on the solvent employed. In aqueous solution, an M2L2 trenchlike compound was obtained. In dimethyl sulfoxide, however, a mixture of the M2L2 trench and an M3L3 macrocycle was found in equilibrium, the dynamic nature of which was confirmed by the concentration-dependent nature of the species. At higher concentration, an M4L4 macrocycle was mostly observed. The complexation of 1 with naked Pd(II) ions was expected to produce novel structures that are combinations of the M(n)L(n) type frameworks. A peculiar tetrahedral M4L8 assembly was obtained quantitatively from 1 and Pd(NO3)2, rather than the smallest possible M3L6 double-walled triangle. Interestingly, the use of Pd(CF3SO3)2 resulted in the sole formation of the latter structure. Thus, the anion is important as a template in the formation of these assemblies. Ligand 2, which contains an extra p-phenylene unit compared to 1, behaved in a similar manner when treated with [Pd(en)(NO3)2], but showed subtle differences with naked Pd(II) ions. With Pd(NO3)2, 2 gave mostly a tetrahedron along with a double-walled triangle. With Pd(CF3SO3)2, this longer ligand formed a double-walled triangle with a negligible amount of tetrahedra. A single discrete assembly of a perfect tetrahedron was obtained from 2 and Pd(II) ions by choosing p-tosylate as a counterion.

  7. Investigation of Cu(II) Binding to Bovine Serum Albumin by Potentiometry with an Ion Selective Electrode

    ERIC Educational Resources Information Center

    Jie Liu

    2004-01-01

    A laboratory project that investigates Cu(II) bind to bovine serum albumin (BSA) in an aqueous solution is developed to assist undergraduate students in gaining better understanding of the interaction of ligands with biological macromolecule. Thus, students are introduced to investigation of Cu(II) binding to BSA by potentiometry with the Cu(II)…

  8. Effect of pectin on adsorption of Cu(II) by two variable-charge soils from southern China.

    PubMed

    Wang, Ru-hai; Zhu, Xiao-fang; Qian, Wei; Yu, Yuan-chun; Xu, Ren-kou

    2015-12-01

    The influence of pectin on Cu(II) adsorption by two variable-charge soils (an Oxisol and an Ultisol) was investigated. Pectin increased the adsorption, and the extent of adsorption increased linearly with the dose of pectin, being greater in the Oxisol than that in the Ultisol because the adsorption of pectin by the Oxisol was greater. Both Langmuir and Freundlich equations fitted the adsorption isotherms of Cu(II) for both soils well. The fitting parameters of both equations indicated that pectin increased not only the adsorption capacity of the soils for Cu(II) but also the adsorption strength of Cu(II). The effect of pectin decreased with rising pH in the pH range 3.5-6.0, although the extent of electrostatic adsorption of Cu(II) by both soils was markedly greater over the pH range. Fourier-transformed infrared spectroscopy analysis and zeta potential measurement of soil colloids indicated that adsorption of pectin by the soils made the negative charge on both soils more negative, which was responsible for the increase in the electrostatic adsorption of Cu(II) induced by the addition of pectin. In conclusion, pectin-enhanced adsorption of Cu(II) especially at low pH would be beneficial to the soils as it would decrease the activity and mobility of Cu(II) in acidic variable-charge soils.

  9. A rhodamine-based dual chemosensor for Cu(II) and Fe(III).

    PubMed

    Sikdar, Anindita; Panja, Sujit Sankar; Biswas, Partha; Roy, Swapnadip

    2012-01-01

    An "off-on" rhodamine-based fluorescence probe for the selective signaling of Cu(II) and Fe(III) has been designed and synthesized. The optical properties of this compound have been investigated in acetonitrile-water (1:1) binary solution. Very interestingly, this compound showed sensitivity and selectivity towards Cu(II) during absorption process and towards Fe(III) during emission process. So this is a nice example of an excellent dual chemosensor for two biologically/physiologically very important transition metal ions using only the two very different techniques (absorption and emission); both cases displayed only intensity enhancement.

  10. Modification of humic acid by ether functional group as biosorbent to Au(III) adsorption in the presence of Sn(II) and Ni(II)

    NASA Astrophysics Data System (ADS)

    Yanti, Ika; Winata, Wahyu Fajar; Sudiono, Sri; Triyono

    2017-03-01

    Modification of humic acid on the phenolic functional group with dimethylsulfate (DMS) for adsorption Au(III) in the presence of Sn(II) and Ni(II) have been conducted. Ash content was analyzed and characterized by Fourier-Transform Infrared (FTIR). Determination of Au(III) adsorption in the presence of Sn(II) and Ni(II) was conducted by Atomic Adsorption Spectroscopy (AAS). The isolated humic acid has 19.8% ash content and after purification has 0.6% ash content, etherified humic acid (EHAs) has 1.4% ash content. Adsorption percentage of Au(III) in the presence of Sn(II) and Ni(II) by EHAs decreased until 4.936% and 41.782% respectively. The addition of Sn(II) and Ni(II) as competitors of Au(III) in the Au(III) adsorption by using EHAs, were affect the percentage of Au(III) adsorption.

  11. An unexpected Schiff base-type Ni(II) complex: synthesis, crystal structures, fluorescence, electrochemical property and SOD-like activities.

    PubMed

    Chai, Lan-Qin; Zhang, Hong-Song; Huang, Jiao-Jiao; Zhang, Yu-Li

    2015-02-25

    An unexpected Schiff base-type Ni(II) complex, [Ni(L(2))2]⋅CH3OH (HL(2) = 1-(2-{[(E)-3, 5-dibromo-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), has been synthesized via complexation of Ni(II) acetate tetrahydrate with HL(1) (2-(3,5-dibromo-2-hydroxyphenyl)-4-methyl-1,2-dihydroquinazoline 3-oxide) originally. HL(1) and its corresponding Ni(II) complex were characterized by IR, (1)H NMR spectra, as well as by elemental analysis, UV-Vis and emission spectroscopy, respectively. Crystal structures of the ligand and complex have been determined by single-crystal X-ray diffraction. Each complex links two other molecules into an infinite 1-D chain via intermolecular hydrogen bonding interactions. Moreover, the electrochemical property of the nickle complex was studied by cyclic voltammetry. In addition, SOD-like activities of HL(1) and Ni(II) complex were also investigated.

  12. Chelation, spectroscopic characterization, biological activity and crystal structure of 2,3-butanedione isonicotinylhydrazone: Determination of Zr4+ after flotation separation

    NASA Astrophysics Data System (ADS)

    Al-Fulaij, O. A.; Jeragh, B.; El-Sayed, A. E. M.; El-Defrawy, M. M.; El-Asmy, A. A.

    2015-02-01

    New metal complexes of Co(II), Ni(II) Cu(II), Zn(II), Cd(II), Pd(II) and Hg(II) with 2,3-butanedione isonicotinylhydrazone [BINH] have been prepared and investigated. Single crystal for BINH is grown and solved as orthorhombic with P 21 21 2 space group. The formula of the ligand was assigned based on the elemental analysis, mass spectra and conductivity measurements. The complexes assigned the formulae [M(BINH-H)Cl]ṡnH2O (Mdbnd Co(II), Ni(II), Cu(II), Zn(II); n = 0 or 1); [Hg(BINH-H)(H2O)2Cl]; [Cd(BINH)Cl2]ṡ2H2O and [Pd(BINH)Cl2]ṡH2O. All complexes are nonelectrolytes. BINH acts as a tridentate ligand in [M(BINH-H)Cl]ṡnH2O and [Hg(BINH-H)(H2O)2Cl] coordinating through Cdbnd Oketonic, Csbnd Oamedic and Cdbnd Nhy and as a neutral bidentate through Cdbnd Oketonic and Cdbnd Nhy in [Cd(BINH)Cl2]ṡ2H2O and [Pd(BINH)Cl2]ṡH2O; the pyridine nitrogen has no rule in coordination. The data are supported by NMR (1H and 13C) spectra. The magnetic moments and electronic spectra provide a tetrahedral structure for the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes; square-planar for the Pd(II) complex and octahedral for the Hg(II) complex. The TGA of the complexes depicted the outer and inner water molecules as well as the final residue. The cobalt and cadmium complexes ended with the metal while the Cu(II), Zn(II) and Pd(II) complexes ended with complex species. [Hg(BINH-H)(H2O)2Cl] has no residue. The ligand is inactive against all tested organisms except for Bacillus thuringiensis. The Hg(II) complex is found more active than the other complexes. The flotation technique is found applicable for the separation of micro amount (10 ppm) of Zr4+ using 10 ppm of BINH and 1 × 10-5 mol L-1 of oleic acid at pH 6 with efficiency of 98% with no interferences.

  13. p53 activation by Ni(II) is a HIF-1α independent response causing caspases 9/3-mediated apoptosis in human lung cells

    SciTech Connect

    Wong, Victor C.; Morse, Jessica L.; Zhitkovich, Anatoly

    2013-06-15

    Hypoxia mimic nickel(II) is a human respiratory carcinogen with a suspected epigenetic mode of action. We examined whether Ni(II) elicits a toxicologically significant activation of the tumor suppressor p53, which is typically associated with genotoxic responses. We found that treatments of H460 human lung epithelial cells with NiCl{sub 2} caused activating phosphorylation at p53-Ser15, accumulation of p53 protein and depletion of its inhibitor MDM4 (HDMX). Confirming the activation of p53, its knockdown suppressed the ability of Ni(II) to upregulate MDM2 and p21 (CDKN1A). Unlike DNA damage, induction of GADD45A by Ni(II) was p53-independent. Ni(II) also increased p53-Ser15 phosphorylation and p21 expression in normal human lung fibroblasts. Although Ni(II)-induced stabilization of HIF-1α occurred earlier, it had no effect on p53 accumulation and Ser15 phosphorylation. Ni(II)-treated H460 cells showed no evidence of necrosis and their apoptosis and clonogenic death were suppressed by p53 knockdown. The apoptotic role of p53 involved a transcription-dependent program triggering the initiator caspase 9 and its downstream executioner caspase 3. Two most prominently upregulated proapoptotic genes by Ni(II) were PUMA and NOXA but only PUMA induction required p53. Knockdown of p53 also led to derepression of antiapoptotic MCL1 in Ni(II)-treated cells. Overall, our results indicate that p53 plays a major role in apoptotic death of human lung cells by Ni(II). Chronic exposure to Ni(II) may promote selection of resistant cells with inactivated p53, providing an explanation for the origin of p53 mutations by this epigenetic carcinogen. - Highlights: • Ni(II) is a strong activator of the transcription factor p53. • Apoptosis is a principal form of death by Ni(II) in human lung epithelial cells. • Ni(II)-activated p53 triggers caspases 9/3-mediated apoptotic program. • NOXA and PUMA are two main proapoptotic genes induced by Ni(II). • HIF-1α and p53 are independent

  14. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases; Part 1: alkyl halide alkylations.

    PubMed

    Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim A

    2013-10-01

    Alkylations of chiral or achiral Ni(II) complexes of glycine Schiff bases constitute a landmark in the development of practical methodology for asymmetric synthesis of α-amino acids. Straightforward, easy preparation as well as high reactivity of these Ni(II) complexes render them ready available and inexpensive glycine equivalents for preparing a wide variety of α-amino acids, in particular on a relatively large scale. In the case of Ni(II) complexes containing benzylproline moiety as a chiral auxiliary, their alkylation proceeds with high thermodynamically controlled diastereoselectivity. Similar type of Ni(II) complexes derived from alanine can also be used for alkylation providing convenient access to quaternary, α,α-disubstituted α-amino acids. Achiral type of Ni(II) complexes can be prepared from picolinic acid or via recently developed modular approach using simple secondary or primary amines. These Ni(II) complexes can be easily mono/bis-alkylated under homogeneous or phase-transfer catalysis conditions. Origin of diastereo-/enantioselectivity in the alkylations reactions, aspects of practicality, generality and limitations of this methodology is critically discussed.

  15. Biological activity of metal complexes. I. Interaction of pt(II), pd(II) and rh(I) complexes with E. coli strains and with mice LS fibroblasts in vitro.

    PubMed

    Aresta, M; Giordano, D; Ingrosso, A; Riccardi, S; Sinigaglia, E

    1979-01-01

    The effects of a number of Pt(II, Pd(II) and Rh(I) complexes against cultures of Escherichia coli (strains B, H10178, uvra-, recA-) and cultures of mice LS Fibroblasts were tested. Most of the compounds showed higher cytotoxic activity than the cis-Pt(NH3)2Cl2, the compound at present on clinical trial as antittumour drug. A new model of active compound is proposed.

  16. Effects of inorganic electrolyte anions on enrichment of Cu(II) ions with aminated Fe3O4/graphene oxide: Cu(II) speciation prediction and surface charge measurement.

    PubMed

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; Wang, Hui; You, Shao-hong; Hu, Xi; Tan, Xiao-fei; Chen, An-wei; Guo, Fang-ying

    2015-05-01

    The present work evaluated the effects of six inorganic electrolyte anions on Cu(II) removal using aminated Fe3O4/graphene oxide (AMGO) in single- and multi-ion systems. A 2(6-2) fractional factorial design (FFD) was employed for assessing the effects of multiple anions on the adsorption process. The results indicated that the Cu(II) adsorption was strongly dependent on pH and could be significantly affected by inorganic electrolyte anions due to the changes in Cu(II) speciation and surface charge of AMGO. In the single-ion systems, the presence of monovalent anions (Cl(-), ClO4(-), and NO3(-)) slightly increased the Cu(II) adsorption onto AMGO at low pH, while the Cu(II) adsorption was largely enhanced by the presence of SO4(2-), CO3(2-), and HPO4(2-). Based on the estimates of major effects and interactions from FFD, the factorial effects of the six selected species on Cu(II) adsorption in multi-ion system were in the following sequence: HPO4(2-)>CO3(2-)>Cl(-)>SO4(2-)>NO3(-)=ClO4(-), and the combined factors of AD (Cl(-)×SO4(2-)) and EF (Cl(-)×SO4(2-)) had significant effects on Cu(II) removal.

  17. Synthesis, structural, optical and anti-rheumatic activity of metal complexes derived from (E)-2-amino-N-(1-(2-aminophenyl)ethylidene)benzohydrazide (2-AAB) with Ru(III), Pd(II) and Zr(IV).

    PubMed

    Hosny, Nasser Mohammed; Sherif, Yousery E

    2015-02-05

    Three new metal complexes derived from Pd(II), Ru(III) and Zr(IV) with (E)-2-amino-N-(1-(2-aminophenyl)ethylidene)benzohydrazide (2-AAB) have been synthesized. The isolated complexes were characterized by elemental analyses, FT-IR, UV-Vis, ES-MS, (1)H NMR, XRD, thermal analyses (TGA and DTA) and conductance. The morphology and the particle size were determined by transmittance electron microscope (TEM). The results showed that, the ligand coordinates to Pd(II) in the enol form, while it coordinates to Ru(III) and Zr(IV) in the keto form. A square planar geometry is suggested for Pd(II) complex and octahedral geometries are suggested for Ru(III) and Zr(IV) complexes. The optical band gaps of the isolated complexes were measured and indicated the semi-conductivity nature of the complexes. The anti-inflammatory and analgesic activities of the ligand and its complexes showed that, Ru(III) complex has higher effect than the well known drug "meloxicam".

  18. A novel dispersive liquid-liquid microextraction method based on solidification of floating organic drop for preconcentration of Pd(II) by graphite furnace atomic absorption spectrometry after complexation by a thienyl substituted 1,2-ethanediamine.

    PubMed

    Ragheb, Elham; Hashemi, Payman; Alizadeh, Kamal; Ganjali, Mohammad Reza

    2015-01-01

    A novel dispersive liquid-liquid microextraction method based on solidification of floating organic drop (DLLME-SFO) was developed for the preconcentration of ultratrace amounts of palladium (Pd)(II) before its determination by electrothermal atomic absorption spectrometry. Diphenyl ether (m.p. 26°C) was used for the first time as a heavier than water organic solvent in the developed method. Pd was complexed by N,N'-bis(thiophen-2-ylmethylene)ethane-1,2-diamine to be extracted into the dispersed diphenyl ether phase using acetonitril as the disperser solvent. Upon cooling and centrifugation, the organic solvent was sedimented at the bottomn and the aqueous phase was easily decantated. Some factors influencing the extraction efficiency of Pd(II) and its subsequent determination, including extraction and dispersive solvent type and volume, pH of sample solution, concentration of the chelating agent and salting out effect, were studied and optimized both with univariate and multivariate methods. Under the optimized conditions, the calibration graph exhibited linearity over a range of 10 - 120 μg L(-1). The enrichment factor was 83.3, the detection limit for Pd (3σ) was 47 ng L(-1) and the relative standard deviation was 3.2% (n = 10, 1 ng mL(-1)). The method was successfully applied to the determination of trace amounts of Pd(II) in water samples.

  19. Adsorption studies of Cu(II) onto biopolymer chitosan and its nanocomposite 5%bentonite/chitosan.

    PubMed

    Moussout, Hamou; Ahlafi, Hammou; Aazza, Mustapha; Zegaoui, Omar; El Akili, Charaf

    2016-01-01

    Chitosan (CS) and nanocomposite 5%bentonite/chitosan (5%Bt/CS) prepared from the natural biopolymer CS were tested to remove Cu(II) ions using a batch adsorption experiment at various temperatures (25, 35 and 45°C). X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis (TGA/DTA) were used in CS and the nanocomposite characterisation. This confirmed the exfoliation of bentonite (Bt) to form the nanocomposite. The adsorption kinetics of copper on both solids was found to follow a pseudo-second-order law at each studied temperature. The Cu(II) adsorption capacity increased as the temperature increased from 25 to 45°C for nanocomposite adsorbent but slightly increased for CS. The data were confronted to the nonlinear Langmuir, Freundlich and Redlich-Peterson models. It was found that the experimental data fitted very well the Langmuir isotherm over the whole temperature and concentration ranges. The maximum monolayer adsorption capacity for the Cu(II) was 404-422 mg/g for CS and 282-337 mg/g for 5%Bt/CS at 25-45°C. The thermodynamic study showed that the adsorption process was spontaneous and endothermic. The complexation of Cu(II) with NH(2) and C = O groups as active sites was found to be the main mechanism in the adsorption processes.

  20. Synthesis, characterization and biological activity of phthalimide derivatives of Cu(II) complex

    NASA Astrophysics Data System (ADS)

    Lingappa, Y.; Rao, S. Sreenivasa; Ravikumar, R. V. S. S. N.; Rao, P. Sambasiva

    The Cu(II) complex of phthalimide-o-aminophenylenediamine has been synthesized by a template method. The complex is characterized by elemental analysis, conductivity measurements and electronic and EPR spectral techniques. The electronic spectra reveal four coordinations for the Cu(II) ion with the ligand. The evaluated spin-Hamiltonian parameters from the EPR spectrum are g|D2.2041, g⊥D2.0263 and A|D166×10-4 cm-1 and A⊥D46×10-4 cm-1E By correlating EPR and electronic data, the calculated bonding parameters are α2D0.7132, αD0.8445, α'D0.6073 and ?. These bonding parameters suggest a moderate covalent nature of the Cu(II) ion with the ligand. Antimicrobial activities of this Cu(II) complex against six bacterial isolates like Bacillus faecalis, Escherichia coil, Pseudomonas aeruginosa, Salmonella typhimurium and Klebsiella pneumoniae are determined.

  1. Calculation of equilibrium binding constants and cooperativity of Cu(II) mixed solvated complexes formation.

    PubMed

    Kudrev, A G

    2012-11-15

    A new extension of matrix approach is proposed to calculate the equilibrium constants of coordinated solvent substitution in a metal ion first salvation shell in the mixed solvent system. The proposed method allows reducing the number of independent variables, necessary to calculate the fractions of species in solution. The equilibrium model of MeCN substitution with DMF and DMSO in the presence of Cu(II) ion for the assessment of structure of intermediate species is presented and verified. The distribution diagrams of Cu(II) species in mixed organic solvents have been analyzed using the modified matrix method. The intrinsic equilibrium constants K of the first solvent molecule replacement in the Cu(II) coordination shell and the correction for the mutual influence between the solvent molecules as ligands in the successive complex formation (cooperativity parameter w) in acetonitrile solution have been calculated from the fitting procedure. It is shown that anticooperative substitution of MeCN by donor ligands in the first coordination shell of the Cu(II) ion is always governed by the change of coordination number during the stepwise process.

  2. The effect of CuII ions in L-asparagine single crystals

    NASA Astrophysics Data System (ADS)

    Santana, Ricardo C.; Gontijo, Henrique O.; Menezes, Arthur F.; Martins, José A.; Carvalho, Jesiel F.

    2016-11-01

    We report the synthesis, crystal growth, and spectroscopic characterization of L-asparagine monohydrate (LAM) single crystals doped with CuII. The crystals were successfully grown by slow cooling from a supersaturated aqueous solution up to size of 16×12×2 mm3;the effect of copper impurities in the crystals morphology was discussed. Electron Paramagnetic Resonance (EPR) was used to calculate the g and hyperfine coupling (A) tensors of the CuII ions (g1=2.044, g2=2.105, g3=2.383and A1≈0, A2=35, A3=108 Gauss). The EPR spectra for certain orientations of the magnetic field suggest that CuII ions are coordinated to two 14N atoms. Correlating the EPR and optical absorption results, the crystal field and the CuII orbital bond parameters were calculated. The results indicate that the paramagnetic center occupies interstitial rhombic distorted site and the ground orbital state for the unpaired electron is the d(x2-y2).

  3. Study on the adsorption of Cu(II) by folic acid functionalized magnetic graphene oxide

    NASA Astrophysics Data System (ADS)

    Wang, Cuicui; Ge, Heyi; Zhao, Yueying; Liu, Shanshan; Zou, Yu; Zhang, Wenbo

    2017-02-01

    The folic acid functionalized magnetic graphene oxide (FA-mGO) as a new adsorbent has been synthesized in this work for the elimination of Cu(II) from waste water. The as-prepared FA-mGO was tested by SEM, TEM, particle size analyzer, FTIR, XRD, Roman spectrum, TGA and magnetic properties analyzer. Some factors, such as adsorbent dose, pH, contact time, initial concentration of adsorbate and temperature were explored. The results showed that the FA-mGO had the better adsorption performance than mGO. After 40 min, the adsorption equilibrium could be reached. Furthermore, the adsorption property obeyed the pseudo-second order kinetic model and the Temkin isotherms well. The maximum adsorption capacity was 283.29 mg/g for Cu(II) from Pseudo-second-order model at pH=5 and 318 K. The chelation action between FA and Cu(II) along with electrostatic incorporation between GO and Cu(II) determined the favourable adsorption property. Besides, thermodynamic studies results ∆G0<0, ∆H0>0, ∆S0>0 suggested that the adsorption mechanism was an endothermic and spontaneous process essentially. Finally, desorption and reusability studies imply FA-mGO has an excellent reproducibility and is benefit to environmental protection and resource conservation.

  4. The new chemical insight for understanding the mechanism of Henry reaction over Cu(II) catalyst

    NASA Astrophysics Data System (ADS)

    Chen, Zhe-Ning; Wang, Kangli; Cui, Deng; Wu, Anan

    2017-04-01

    In this work, we present an alternative mechanism without the initial coordination of reactant and catalyst for the asymmetric Henry reaction over Cu(II) catalyst. Our calculations show that the re-coordination of acetate and Cu center is essential for the enantioselectivity. Thus, any effect of the re-coordination process would affect the enantioselectivity for this reaction.

  5. Adsorption studies of Cu(II) on Boston fern (Nephrolepis exaltata Schott cv. Bostoniensis) leaves

    NASA Astrophysics Data System (ADS)

    Rao, Rifaqat Ali Khan; Khan, Umra

    2016-02-01

    Adsorption studies were done on Boston fern leaves for the effective removal of Cu(II) ions from aqueous solution. It has been tested for the first time for heavy metal adsorption from aqueous solution. This promising material has shown remarkable adsorption capacity towards Cu(II) ions which confirm its novelty, ease of availability, non-toxic nature, cheapness, etc., and give the main innovation to the present study. The adsorbent was analyzed by FT-IR, SEM and EDS. The effect of pH, contact time, initial metal ion concentration and temperature on the adsorption was investigated using batch process to optimize conditions for maximum adsorption. The adsorption of Cu(II) was maximum (96 %) at pH 4. The experimental data were analyzed by Langmuir, Freundlich and Tempkin isotherms. The kinetic studies of Cu(II)were carried out at room temperature (30 °C) in the concentration range 10-100 mg L-1. The data obtained fitted well with the Langmuir isotherm and pseudo-second-order kinetics model. The maximum adsorption capacity (q m) obtained from Langmuir adsorption isotherm was found to be 27.027 mg g-1 at 30 °C. The process was found to be exothermic and spontaneous in nature. The breakthrough and exhaustive capacities were found to be 12.5 and 37.5 mg g-1, respectively. Desorption studies showed that 93.3 % Cu(II) could be desorbed with 0.1 M HCl by continuous mode.

  6. Effective removal of Ni(II) from aqueous solutions by modification of nano particles of clinoptilolite with dimethylglyoxime.

    PubMed

    Nezamzadeh-Ejhieh, Alireza; Kabiri-Samani, Mehdi

    2013-09-15

    In this work an Iranian natural clinoptilolite tuff was pre-treated and changed to the micro (MCP) and nano (NCP) particles by mechanical method. Modification of micro and nano particles and also their Ni-exchanged forms were done by dimethylglyoxime (DMG). The raw and modified samples were characterized by XRD, FT-IR, SEM, BET, TG-DTG and energy dispersive analysis X-ray spectroscopy (EDAX). Removal of Ni(II) by modified and unmodified samples was investigated in batch procedure. It was found that NCP-DMG has higher capacity for removal of Ni(II). The effects of analytical parameters such as pH, dose of DMG, concentration of nickel solution, contact time and selectivity were studied and the optimal operation parameters were found as follows: pHPZC: 7.6, CNi(II): 0.01 M, contact time: 360 min and DMG dosage: 5mM. The results of selectivity experiments showed that the modified zeolite has a good selectivity for nickel in the presence of different multivalent cations. Langmuir and Freundlich isotherm models were adopted to describe the adsorption isotherms. Adsorption isotherms of Ni(II) ions could be best modelled by Langmuir equation, that indicate the monolayer sorption of Ni(II). Comparison of two kinetic models indicates that the adsorption kinetic can be well described by the pseudo-second-order rate equation that indicates that the rate limiting step for the process involves chemical reaction. The negative ΔH and ΔG indicate an exothermic and spontaneously process. The negative ΔS indicates that the adsorption of nickel cations from solution occurs with lower amount ion replacement, thus chemisorptions due to complex formation are dominant process in nickel removal.

  7. Ni(II) Tol-BINAP-catalyzed enantioselective Michael reactions of beta-ketoesters and unsaturated N-acylthiazolidinethiones.

    PubMed

    Evans, David A; Thomson, Regan J; Franco, Francisco

    2005-08-10

    The enantioselective addition of beta-ketoesters to unsaturated N-acylthiazolidinethiones catalyzed by Ni(II) Tol-BINAP Lewis acid complexes is reported. Notable features of this reaction are its operation simplicity, the obviated need for the addition of an external base, and the ease with which the adducts are converted into a range of potentially useful derivatives. In particular, the dihydropyrone adducts are versatile scaffolds for further stereoselective elaboration.

  8. Nuclease activity and interaction studies of unsymmetrical binuclear Ni(II) complexes with CT-DNA and BSA.

    PubMed

    Poornima, S; Gunasekaran, K; Kandaswamy, M

    2015-10-07

    New unsymmetrical binuclear nickel(II) complexes [Ni2L(1-5)] (ClO4)2 (1-5) were synthesized by using [NiL] [(3-((9E)-(2-((E)-(3-formyl-2-olato-5-methylbenzylideneamino)methyl) phenylimino)methyl)-3-formyl-5-methyl-2-olato)nickel(II)] with various diamines like 1,2-diaminoethane (L(1)), 1,3-diaminopropane (L(2)), 1,4-diaminobutane (L(3)), 1,2-diaminobenzene (L(4)) and 1,8-diaminonaphthalene (L(5)) and characterized by elemental analysis and spectroscopic methods. The molecular structure of binuclear nickel(II) complex 1 is determined by a single crystal X-ray diffraction method. Cyclic voltammograms of binuclear Ni(II) complexes exhibit two quasi-reversible reduction waves in the cathodic region and two oxidation waves in the anodic region. DNA binding, protein binding and DNA cleavage studies were investigated. The interactions of complexes (1-5) with calf thymus DNA were studied by spectroscopic techniques, including absorption and fluorescence methods. The binding affinities of complexes (1-5) with CT-DNA and nuclease activities are in the following order: 5> 4>3 >2>1 . Binuclear Ni(II) complex 1 cleaved the plasmid DNA by a hydrolytic pathway. The hydrolytic cleavage of DNA by the complexes is supported by evidence from free radical quenching and T4 ligase ligation. Binuclear Ni(II) complexes (1-5) displayed significant protein (bovine serum albumin) interactions. The experimental results showed that the interaction between binuclear Ni(II) complexes and BSA was mainly a static quenching process.

  9. Biosorption of Cu(II) by immobilized microalgae using silica: kinetic, equilibrium, and thermodynamic study.

    PubMed

    Lee, Hongkyun; Shim, Eunjung; Yun, Hyun-Shik; Park, Young-Tae; Kim, Dohyeong; Ji, Min-Kyu; Kim, Chi-Kyung; Shin, Won-Sik; Choi, Jaeyoung

    2016-01-01

    Immobilized microalgae using silica (IMS) from Micractinium reisseri KGE33 was synthesized through a sol-gel reaction. Green algal waste biomass, the residue of M. reisseri KGE33 after oil extraction, was used as the biomaterial. The adsorption of Cu(II) on IMS was tested in batch experiments with varying algal doses, pH, contact times, initial Cu(II) concentrations, and temperatures. Three types of IMSs (IMS 14, 70, and 100) were synthesized according to different algal doses. The removal efficiency of Cu(II) in the aqueous phase was in the following order: IMS 14 (77.0%) < IMS 70 (83.3%) < IMS 100 (87.1%) at pH 5. The point of zero charge (PZC) value of IMS100 was 4.5, and the optimum pH for Cu(II) adsorption was 5. Equilibrium data were described using a Langmuir isotherm model. The Langmuir model maximum Cu(II) adsorption capacity (q m) increased with the algal dose in the following order: IMS 100 (1.710 mg g(-1)) > IMS 70 (1.548 mg g(-1)) > IMS 14 (1.282 mg g(-1)). The pseudo-second-order equation fitted the kinetics data well, and the value of the second-order rate constant increased with increasing algal dose. Gibbs free energies (ΔG°) were negative within the temperature range studied, which indicates that the adsorption process was spontaneous. The negative value of enthalpy (ΔH°) again indicates the exothermic nature of the adsorption process. In addition, SEM-energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses of the IMS surface reveal that the algal biomass on IMS is the main site for Cu(II) binding. This study shows that immobilized microalgae using silica, a synthesized biosorbent, can be used as a cost-effective sorbent for Cu(II) removal from the aqueous phase.

  10. Optimizing Cu(II) removal from aqueous solution by magnetic nanoparticles immobilized on activated carbon using Taguchi method.

    PubMed

    Ebrahimi Zarandi, Mohammad Javad; Sohrabi, Mahmoud Reza; Khosravi, Morteza; Mansouriieh, Nafiseh; Davallo, Mehran; Khosravan, Azita

    2016-01-01

    This study synthesized magnetic nanoparticles (Fe(3)O(4)) immobilized on activated carbon (AC) and used them as an effective adsorbent for Cu(II) removal from aqueous solution. The effect of three parameters, including the concentration of Cu(II), dosage of Fe(3)O(4)/AC magnetic nanocomposite and pH on the removal of Cu(II) using Fe(3)O(4)/AC nanocomposite were studied. In order to examine and describe the optimum condition for each of the mentioned parameters, Taguchi's optimization method was used in a batch system and L9 orthogonal array was used for the experimental design. The removal percentage (R%) of Cu(II) and uptake capacity (q) were transformed into an accurate signal-to-noise ratio (S/N) for a 'larger-the-better' response. Taguchi results, which were analyzed based on choosing the best run by examining the S/N, were statistically tested using analysis of variance; the tests showed that all the parameters' main effects were significant within a 95% confidence level. The best conditions for removal of Cu(II) were determined at pH of 7, nanocomposite dosage of 0.1 gL(-1) and initial Cu(II) concentration of 20 mg L(-1) at constant temperature of 25 °C. Generally, the results showed that the simple Taguchi's method is suitable to optimize the Cu(II) removal experiments.

  11. Cu(II) Catalytic Reduction of Cr(VI) by Tartaric Acid Under the Irradiation of Simulated Solar Light

    PubMed Central

    Li, Ying; Qin, Chao; Zhang, Jing; Lan, Yeqing; Zhou, Lixiang

    2014-01-01

    Abstract Cu(II) catalytic reduction of Cr(VI) by tartaric acid under the irradiation of simulated solar light was investigated through batch experiments at pHs from 3 to 6 and at temperatures from 15°C to 35°C. Results demonstrated that introduction of Cu(II) could markedly improve reduction of Cr(VI) in comparison with tartaric acid alone. Optimal removal of Cr(VI) was achieved at pH 4. Reduction of Cr(VI) increased with increasing temperatures and initial concentrations of Cu(II) and tartaric acid. The catalytic role of Cu(II) in the reduction of Cr(VI) was ascribed to the formation of Cu(II)-tartaric acid complex, which generated active reductive intermediates, including Cu(I) and tartaric acid radicals through a pathway of metal–ligand–electron transfer with light. Cu(II) photocatalytic reduction of Cr(VI) by tartaric acid followed pseudo zero-order kinetics with regard to Cr(VI), and the activation energy was calculated to be 21.48 kJ/mol. To date, such a role of Cu(II) has not been reported. The results from the present study are helpful in fully understanding the photochemical reductive behavior of Cr(VI) in the presence of both tartaric acid and Cu(II) in soil and aquatic environments. PMID:25125941

  12. Cu(II) Catalytic Reduction of Cr(VI) by Tartaric Acid Under the Irradiation of Simulated Solar Light.

    PubMed

    Li, Ying; Qin, Chao; Zhang, Jing; Lan, Yeqing; Zhou, Lixiang

    2014-08-01

    Cu(II) catalytic reduction of Cr(VI) by tartaric acid under the irradiation of simulated solar light was investigated through batch experiments at pHs from 3 to 6 and at temperatures from 15°C to 35°C. Results demonstrated that introduction of Cu(II) could markedly improve reduction of Cr(VI) in comparison with tartaric acid alone. Optimal removal of Cr(VI) was achieved at pH 4. Reduction of Cr(VI) increased with increasing temperatures and initial concentrations of Cu(II) and tartaric acid. The catalytic role of Cu(II) in the reduction of Cr(VI) was ascribed to the formation of Cu(II)-tartaric acid complex, which generated active reductive intermediates, including Cu(I) and tartaric acid radicals through a pathway of metal-ligand-electron transfer with light. Cu(II) photocatalytic reduction of Cr(VI) by tartaric acid followed pseudo zero-order kinetics with regard to Cr(VI), and the activation energy was calculated to be 21.48 kJ/mol. To date, such a role of Cu(II) has not been reported. The results from the present study are helpful in fully understanding the photochemical reductive behavior of Cr(VI) in the presence of both tartaric acid and Cu(II) in soil and aquatic environments.

  13. Interactive effects of sulfadiazine and Cu(II) on their sorption and desorption on two soils with different characteristics.

    PubMed

    Xu, Yonggang; Yu, Wantai; Ma, Qiang; Zhou, Hua

    2015-11-01

    Antibiotics and heavy metals often coexist in soils due to land application of animal wastes and other sources of inputs. The aim of this study is to evaluate the interaction of Cu(II) and sulfadiazine (SDZ) regarding to their sorption and desorption on Brown soil (BS, luvisols) and Red soil (RS, Udic Ferrosols) using batch experiments. The presence of Cu(II) significantly enhanced sorption of SDZ on BS at pH>5.0, and this trend increased with increasing pH, which was mainly ascribed to the formation of ternary complexes of Cu-SDZ-soil and/or SDZ-Cu-soil. In contrast, Cu(II) only slightly increased SDZ sorption on RS at pH<5.0 due to the decrease of equilibrium solution pH, whereas it hardly affected SDZ sorption at pH>5.0 because RS had high oxides contents and low affinity for Cu(II). In addition, Cu(II) inhibited SDZ desorption from BS but promoted SDZ desorption from RS, which was related to their different sorption mechanisms. The presence of SDZ exerted no significant effect on the sorption of Cu(II) on the two soils at pH<6.5 because of its low sorption coefficients (Kd), while slightly decreased Cu(II) sorption at pH>6.5 by forming water-soluble complexes. Furthermore, SDZ had little effect on Cu(II) desorption from the two soils at natural pH. These results indicate that soil characteristics strongly influence the interactions of Cu(II) and SDZ on their sorption and desorption on soils.

  14. Cu(II) binding by a pH-fractionated fulvic acid

    USGS Publications Warehouse

    Brown, G.K.; Cabaniss, S.E.; MacCarthy, P.; Leenheer, J.A.

    1999-01-01

    The relationship between acidity, Cu(II) binding and sorption to XAD resin was examined using Suwannee River fulvic acid (SRFA). The work was based on the hypothesis that fractions of SRFA eluted from an XAD column at various pH's from 1.0 to 12.0 would show systematic variations in acidity and possibly aromaticity which in turn would lead to different Cu(II) binding properties. We measured equilibrium Cu(II) binding to these fractions using Cu2+ ion-selective electrode (ISE) potentiometry at pH 6.0. Several model ligands were also examined, including cyclopentane-1,2,3,4-tetracarboxylic acid (CP-TCA) and tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THF-TCA), the latter binding Cu(II) much more strongly as a consequence of the ether linkage. The SRFA Cu(II) binding properties agreed with previous work at high ionic strength, and binding was enhanced substantially at lower ionic strength, in agreement with Poisson-Boltzmann predictions for small spheres. Determining Cu binding constants (K(i)) by non-linear regression with total ligand concentrations (L(Ti)) taken from previous work, the fractions eluted at varying pH had K(i) similar to the unfractionated SRFA, with a maximum enhancement of 0.50 log units. We conclude that variable-pH elution from XAD does not isolate significantly strong (or weak) Cu(II)-binding components from the SRFA mixture. Copyright (C) 1999 Elsevier Science B.V.

  15. Influence of Cu(II) on the interaction between sulfite and horseradish peroxidase in vitro

    NASA Astrophysics Data System (ADS)

    Lan, Jie; Guo, Dong-Sheng; Yuan, Xiao-Ying

    2007-06-01

    This paper discussed the quantitative influence of Cu(II) on the interaction between horseradish peroxidase (HRP) and sulfite (SO 32-), which is a derivate of sulfite dioxide in human bodies, by using fluorescence spectrum and ultraviolet (UV) absorption spectrometry in vitro. The results show that under the conditions of physiological pH and room-temperature, Cu(II) can bind strongly with both the protein part and the ferroporphyrin part in HRP at a low concentration (10 -4 mol L -1), and the combination constants are 2.047 × 10 3 and 7.66 × 10 2 L mol -1, respectively. Under the same conditions, SO 32- at low concentrations (<0.15 mol L -1) has little quenching for the fluorescence of HRP at 330 nm, and the combination constant is 0.108 L mol -1. While the fluorescence intensity at 440 nm enhance gradually with the increased concentration of SO 32- (<0.1 mol L -1), and the combination constant is 8.219 L mol -1. These indicate that SO 32- at low concentration has little reaction with the enzyme protein part in HRP but obvious reaction with the ferroporphyrin part in HRP. After SO 32- at low concentrations is added into the HRP-Cu(II) binary system, the reaction constants between SO 32- and the enzyme protein part in HRP increase rapidly. Compared with the absence of Cu(II), the combination constant of SO 32- with the enzyme protein part in HRP increases nearly 70 times with a certain Cu(II) concentration (5.0 × 10 -4 mol L -1) in the system. However, the presence of Cu(II) in the system has little effect on the reaction constants between SO 32- and the ferroporphyrin part in HRP.

  16. EPR Methods for Biological Cu(II): L-Band CW and NARS

    PubMed Central

    Bennett, Brian; Kowalski, Jason

    2016-01-01

    Copper has many roles in biology that involve the change of coordination sphere and/or oxidation state of the copper ion. Consequently, the study of copper in heterogeneous environments is an important area in biophysics. EPR is a primary technique for the investigation of paramagnetic copper, which is usually the isolated Cu(II) ion, but sometimes as Cu(II) in different oxidation states of multi-transition ion clusters. The gross geometry of the coordination environment of Cu(II) can often be determined from a simple inspection of the EPR spectrum, recorded in the traditional X-band frequency range (9 – 10 GHz). Identification and quantitation of the coordinating ligand atoms, however, is not so straightforward. In particular, analysis of the superhyperfine structure on the EPR spectrum, to determine the number of coordinated nitrogen atoms, is fraught with difficulty at X-band, despite the observation that the overwhelming number of EPR studies of Cu(II) in the literature have been carried out at X-band. Greater reliability has been demonstrated at S-band (3 – 4 GHz), using the low-field parallel (gz) features. However, analysis relies on clear identification of the outermost superhyperfine line, which has the lowest intensity of all the spectral features. Computer simulations have subsequently indicated that the much more intense perpendicular region of the spectrum can be reliably interpreted at L-band (2 GHz). The present work describes the development of L-band EPR of Cu(II) into a routine method, that is applicable to biological samples. PMID:26478491

  17. FTIR spectroscopic characterization of Cu(II) coordination compounds with exopolysaccharide pullulan and its derivatives

    NASA Astrophysics Data System (ADS)

    Mitić, Ž.; Nikolić, G. S.; Cakić, M.; Premović, P.; Ilić, Lj.

    2009-04-01

    Pullulan is a water-soluble, extracellular neutral polysaccharide with a linear flexible chain of α-(1 → 6)-linked maltotriose units, the structure of which is intermediate between pullulan and amylose structures because of the co-existence of both α-(1 → 6) and α-(1 → 4)-glycosidic linkages in single compounds. In alkali solutions Cu(II) ion forms complexes with reduced low-molar pullulan (RLMP). The metal content and the solution composition depends on pH. The complexing process begins in a weak alkali solution (pH > 7), and involves OH groups in C(2) and C(3) or C(6) pullulan monomer units (α- D-glucopyranose). Complexes of Cu(II) ion with reduced low-molar pullulan were synthesized in the water solutions, at the boiling temperature and at different pH values (7.512). Fourier-Transform Infrared (FTIR) spectroscopic data of synthesized complexes are rare in literature. FTIR spectroscopic characterization (FTIR, LNT-FTIR, ATR-FTIR, and FTIR microspectroscopy) of Cu(II) ion complexes with RLMP ( M w 6000 g mol -1) was carried out in this work. The similarities of the γ(C sbnd H) range in a part of FTIR spectra indicate that there is no difference in the conformation of the C 1 glucopyranose (Glc) unit in the RLMP and synthesized Cu(II) complexes. The complexing Cu(II) ion with RLMP in the dependence from the pH form different types of complex (pH 7-8: Cu(II)(Glc) 2(H 2O) 2, pH 8-10: Cu(II)(Glc) 2(H 2O)(OH), pH 10-12: Cu(II)(Glc) 2(OH) 2).

  18. Single Crystal EPR and Optical Studies of Cu(II) Doped Zinc Ammonium Phosphate Hexahydrate: A Case of Rhombic Distortion

    NASA Astrophysics Data System (ADS)

    Poonguzhali, E.; Srinivasan, R.; Ravikumar, R. V. S. S. N.; Ravikumar, R. V. S. S. N.; Chandrasekhar, A. V.; Reddy, B. J.; Reddy, Y. P.; Sambasiva Rao, P.

    Single crystal EPR and optical studies of Cu(II) doped ZnNH4PO4·6H2O (Zinc struvite) have been carried out at room and liquid nitrogen temperatures. The g and A tensors indicate that the impurity has entered the lattice substitutionally. Even though the coordination polyhedron around the host Zn(II) is a compressed octahedron of oxygen atoms of water, the Cu(II) ion has an elongated octahedron corresponding to dx2-y2 ground state. The optical spectrum shows four bands at 1205, 1095, 833 and 805nm, which confirms the octahedral coordination of Cu(II) with rhombic (C2V) distortion.

  19. Amine-based extraction recovery of Cu(II) from aqueous solutions in the presence of EDTA. Equilibrium studies

    SciTech Connect

    Juang, R.S.; Chen, Y.J.; Huang, I.P.

    1999-11-01

    The distribution ratios of Cu(II) between kerosene solutions of Aliquat 336 and water containing EDTA (ethylenediaminetetraacetic acid) are measured. Experiments were performed as a function of the pH, the concentration of Cu(II), the concentration ratio of EDTA to Cu(II), and the concentration of amine. It is shown that the distribution ratios first increase with pH and then decrease with further increase in pH up to 7.0. The effect of temperature on the extraction was studied, and the enthalpy of the extraction reaction was determined. Finally, the nonideal behavior of the organic phase is discussed.

  20. A bifunctional non-natural tetrapeptide modulates amyloid-beta peptide aggregation in the presence of Cu(ii).

    PubMed

    Márquez, Maripaz; Blancas-Mejía, Luis M; Campos, Adriana; Rojas, Luis; Castañeda-Hernández, Gilberto; Quintanar, Liliana

    2014-12-01

    Amyloid-beta peptide (Aβ) aggregation is one of the hallmarks of Alzheimer's disease (AD), and metal ions such as Cu(ii) have been proposed to play a role in amyloid formation and the onset of this progressive neurodegenerative disorder. This study reports the design and characterization of a novel bifunctional non-natural tetrapeptide, Met-Asp-d-Trp-Aib, that is capable of binding copper, competing with Aβ for Cu(ii), and modulating Aβ aggregation. The study of this tetrapeptide provides further insights into the role of Cu(ii) in the Aβ aggregation pathway, and into the design of compounds with therapeutic potential for Alzheimer's disease.

  1. Link between Affinity and Cu(II) Binding Sites to Amyloid-β Peptides Evaluated by a New Water-Soluble UV-Visible Ratiometric Dye with a Moderate Cu(II) Affinity.

    PubMed

    Conte-Daban, Amandine; Borghesani, Valentina; Sayen, Stéphanie; Guillon, Emmanuel; Journaux, Yves; Gontard, Geoffrey; Lisnard, Laurent; Hureau, Christelle

    2017-02-07

    Being able to easily determine the Cu(II) affinity for biomolecules of moderate affinity is important. Such biomolecules include amyloidogenic peptides, such as the well-known amyloid-β peptide involved in Alzheimer's disease. Here, we report the synthesis of a new water-soluble ratiometric Cu(II) dye with a moderate affinity (10(9) M(-1) at pH 7.1) and the characterizations of the Cu(II) corresponding complex by X-ray crystallography, EPR, and XAS spectroscopic methods. UV-vis competition was performed on the Aβ peptide as well as on a wide series of modified peptides, leading to an affinity value of 1.6 × 10(9) M(-1) at pH 7.1 for the Aβ peptide and to a coordination model for the Cu(II) site within the Aβ peptide that agrees with the one mostly accepted currently.

  2. EXAFS in total reflection (reflEXAFS) for the study of organometallic Pd(II) thiol complexes based self-assembled monolayers on gold

    NASA Astrophysics Data System (ADS)

    Battocchio, C.; Fratoddi, I.; Venditti, I.; Yarzhemsky, V. G.; Norov, Yu. V.; Russo, M. V.; Polzonetti, G.

    2011-01-01

    The molecular structure and organization of self-assembled monolayers (SAMs) and multilayer films grafted onto Au/Si(1 1 1) surfaces of mononuclear transition metal dialkynyl bridged Pd(II) complexes trans-[HS-Pd(PBu 3) 2-SH] ( 1), trans-[HS-Pd(PBu 3) 2(-C tbnd C-C 6H 5)] ( 2) and of the binuclear complex trans, trans-[HS-Pd(PBu 3) 2(-C tbnd C-C 6H 4-C 6H 4-C tbnd C-Pd(PBu 3) 2-SH] ( 3), have been investigated by extended X-ray absorption fine structure spectroscopy in total reflection conditions (reflEXAFS). ReflEXAFS analysis of the data lead to determine the local structure around Pd atoms, assessing the square-planar geometry around the transition metal in the multilayers case, preserved in the monolayer regime. The investigation on the SAMs also provided the assessment of the S-Au bond length and Pd-S-Au bond angle and on the molecular orientation on the gold substrate of the complexes, confirmed by quantum chemical calculations.

  3. Competitive adsorption of Cu(II) and Cd(II) ions by chitosan crosslinked with epichlorohydrin-triphosphate.

    PubMed

    Laus, Rogério; de Fávere, Valfredo Tadeu

    2011-10-01

    In this study, chitosan (CTS) was crosslinked with both epichlorohydrin (ECH) and triphosphate (TPP), by covalent and ionic crosslinking reactions, respectively. The resulting adsorbent (CTS-ECH-TPP) was characterized by SEM, CHN, EDS, FT-IR and TGA analyses, and tested for metal adsorption. The adsorbent was used in batch experiments to evaluate the adsorption of Cu(II) and Cd(II) ions in single and binary metal solutions. In single metal solutions the maximum adsorption capacities for Cu(II) and Cd(II) ions, obtained by Langmuir model, were 130.72 and 83.75 mg g⁻¹, respectively. Adsorption isotherms for binary solutions showed that the presence of Cu(II) decreased Cd(II) adsorption due to a significant competition effect, that is, the adsorbent was selective towards Cu(II) rather than Cd(II).

  4. Experiment, modeling and optimization of liquid phase adsorption of Cu(II) using dried and carbonized biomass of Lyngbya majuscula

    NASA Astrophysics Data System (ADS)

    Kushwaha, Deepika; Dutta, Susmita

    2015-07-01

    The present work aims at evaluation of the potential of cyanobacterial biomass to remove Cu(II) from simulated wastewater. Both dried and carbonized forms of Lyngbya majuscula, a cyanobacterial strain, have been used for such purpose. The influences of different experimental parameters viz., initial Cu(II) concentration, solution pH and adsorbent dose have been examined on sorption of Cu(II). Kinetic and equilibrium studies on Cu(II) removal from simulated wastewater have been done using both dried and carbonized biomass individually. Pseudo-second-order model and Langmuir isotherm have been found to fit most satisfactorily to the kinetic and equilibrium data, respectively. Maximum 87.99 and 99.15 % of Cu(II) removal have been achieved with initial Cu(II) concentration of 10 and 25 mg/L for dried and carbonized algae, respectively, at an adsorbent dose of 10 g/L for 20 min of contact time and optimum pH 6. To optimize the removal process, Response Surface Methodology has been employed using both the dried and carbonized biomass. Removal with initial Cu(II) concentration of 20 mg/L, with 0.25 g adsorbent dose in 50 mL solution at pH 6 has been found to be optimum with both the adsorbents. This is the first ever attempt to make a comparative study on Cu(II) removal using both dried algal biomass and its activated carbon. Furthermore, regeneration of matrix was attempted and more than 70% and 80% of the adsorbent has been regenerated successfully in the case of dried and carbonized biomass respectively upto the 3rd cycle of regeneration study.

  5. Adsorption of Cu(II) on Oxidized Multi-Walled Carbon Nanotubes in the Presence of Hydroxylated and Carboxylated Fullerenes

    PubMed Central

    Wang, Jing; Li, Zhan; Li, Shicheng; Qi, Wei; Liu, Peng; Liu, Fuqiang; Ye, Yuanlv; Wu, Liansheng; Wang, Lei; Wu, Wangsuo

    2013-01-01

    The adsorption of Cu(II) on oxidized multi-walled carbon nanotubes (oMWCNTs) as a function of contact time, pH, ionic strength, temperature, and hydroxylated fullerene (C60(OH)n) and carboxylated fullerene (C60(C(COOH)2)n) were studied under ambient conditions using batch techniques. The results showed that the adsorption of Cu(II) had rapidly reached equilibrium and the kinetic process was well described by a pseudo-second-order rate model. Cu(II) adsorption on oMWCNTs was dependent on pH but independent of ionic strength. Compared with the Freundlich model, the Langmuir model was more suitable for analyzing the adsorption isotherms. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that Cu(II) adsorption on oMWCNTs was spontaneous and endothermic. The effect of C60(OH)n on Cu(II) adsorption of oMWCNTs was not significant at low C60(OH)n concentration, whereas a negative effect was observed at higher concentration. The adsorption of Cu(II) on oMWCNTs was enhanced with increasing pH values at pH < 5, but decreased at pH ≥ 5. The presence of C60(C(COOH)2)n inhibited the adsorption of Cu(II) onto oMWCNTs at pH 4–6. The double sorption site model was applied to simulate the adsorption isotherms of Cu(II) in the presence of C60(OH)n and fitted the experimental data well. PMID:24009683

  6. Zn(II) ions substantially perturb Cu(II) ion coordination in amyloid-β at physiological pH.

    PubMed

    Silva, K Ishara; Saxena, Sunil

    2013-08-15

    The interaction of Cu(II) and Zn(II) ions with amyloid-β (Aβ) plays an important role in the etiology of Alzheimer's disease. We describe the use of electron spin resonance (ESR) to measure metal-binding competition between Cu(II) and Zn(II) in amyloid-β at physiological pH. Continuous wave ESR measurements show that the affinity of Cu(II) toward Aβ(1-16) is significantly higher than that of Zn(II) at physiological pH. Importantly, of the two known Cu(II) coordination modes in Aβ, component I and component II, Zn(II) displaces Cu(II) only from component I. Our results indicate that at excess amounts of Zn(II) component II becomes the most dominant coordination mode. This observation is important as Aβ aggregates in the brain contain a high Zn(II) ion concentration. In order to determine details of the metal ion competition, electron spin echo envelope modulation experiments were carried out on Aβ variants that were systematically (15)N labeled. In the presence of Zn(II), most peptides use His 14 as an equatorial ligand to bind Cu(II) ions. Interestingly, Zn(II) ions completely substitute Cu(II) ions that are simultaneously coordinated to His 6 and His 13. Furthermore, in the presence of Zn(II), the proportion of Cu(II) ions that are simultaneously coordinated to His 13 and His 14 is increased. On the basis of our results we suggest that His 13 plays a critical role in modulating the morphology of Aβ aggregates.

  7. Synthesis and characterization of hydroxyapatite nanoparticles impregnated on apple pomace to enhanced adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution.

    PubMed

    Chand, Piar; Pakade, Yogesh B

    2015-07-01

    Hydroxyapatite nanoparticles were synthesized, characterized, and impregnated onto apple pomace surface (HANP@AP) for efficient removal of Pb(II), Cd(II), and Ni(II) ions from water. HANP@AP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD), and surface area analysis. Batch sorption studies were carried out to investigate the influence of different parameters as amount of dose (g), pH, time (min), and initial concentration (mg L(-1)) on adsorption process. Experimental kinetic data followed pseudo-second-order model and equilibrium data well fitted to Langmuir adsorption model with maximum adsorption capacities of 303, 250, and 100 mg g(-1) for Pb(II), Cd(II), and Ni(II) ions, respectively. Competitive adsorption of Pb(II), Cd(II), and Ni(II) ions in presences of each other was studied to evaluate the removal efficiency of HANP@AP against multi metal-loaded water. HANP@AP was successfully applied to real industrial wastewater with 100 % removal of all three metal ions even at high concentration. HANP@AP could be recycled for four, four, and three cycles in case of Pb(II), Cd(II) and Ni(II), respectively. The study showed that HANP@AP is fast, cost effective, and environmental friendly adsorbent for removal of Pb(II), Cd(II), and Ni(II) ions from real industrial wastewater.

  8. Metallation of ethylenediamine based Schiff base with biologically active Cu(II), Ni(II) and Zn(II) ions: synthesis, spectroscopic characterization, electrochemical behaviour, DNA binding, photonuclease activity and in vitro antimicrobial efficacy.

    PubMed

    Raman, N; Selvan, A; Sudharsan, S

    2011-09-01

    A new ligand [C28H20N6O8] (L2) has been synthesized by the condensation reaction of 3-hydroxy-4-nitrobenzaldehydenephenylhydrazine (L1) with diethyloxalate. This ligand L2 is allowed to react with bis(ethylenediamine)Cu(II)/Ni(II)/Zn(II) complexes. It affords [(L2)Cu(en)2]Cl2(1)/[(L2)Ni(en)2]Cl2(2)/[(L2)Zn(en)2]Cl2(3) complexes, respectively. These complexes (1-3) have been characterized by the spectral and analytical techniques. The interaction of these complexes with calf thymus (CT) DNA is characterized by the absorption spectra which exhibit a slight red shift with hypochromic effect. Electrochemical analyses and viscosity measurements have also been carried out to determine the mode of binding. The shift in ΔEp, E1/2 and Ipc values explores the interaction of CT DNA with the above metal complexes. The slight increase in the viscosity of CT DNA indicates that these complexes bind to CT DNA through a partial non-classical intercalative mode. Cleavage experiments using pBR322 DNA in presence of H2O2 indicate that these complexes behave as efficient artificial chemical nucleases in the order of 1>2>3. Moreover, the antibacterial and antifungal studies reveal that complex 1 is highly active against the bacterial and fungal growth.

  9. Synthesis, spectroscopic characterization and antimicrobial studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff bases derived from 5-bromo-salicylaldehyde

    NASA Astrophysics Data System (ADS)

    Kursunlu, Ahmed Nuri; Guler, Ersin; Sevgi, Fatih; Ozkalp, Birol

    2013-09-01

    In this study, the new Schiff base ligands derived from condensation of amine and 5-bromo-salicylaldehyde were characterized. All compounds, the Schiff bases and the metal complexes, were characterized by elemental analyzes, FT-IR, 1H NMR, 13C NMR and magnetic susceptibility measurements. The synthesized ligands, along with their metal (II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis) and four Gram-positive (Streptococcus pyogones, Bacillus cereus, Staphylococcus aureus and Methicillin-resistant S. aureus) bacterial strains by using disc diffusion and broth microdilution techniques.

  10. Synthesis, spectral characterization, in vitro antibacterial, antifungal and cytotoxic activities of Co(II), Ni(II) and Cu(II) complexes with 1,2,4-triazole Schiff bases.

    PubMed

    Bagihalli, Gangadhar B; Avaji, Prakash Gouda; Patil, Sangamesh A; Badami, Prema S

    2008-12-01

    A series of metal complexes of cobalt(II), nickel(II) and copper(II) have been synthesized with newly synthesized biologically active 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole and 8-formyl-7-hydroxy-4-methylcoumarin, which have been characterized by elemental analyses, spectroscopic measurements (IR, UV-vis, fluorescence, ESR), magnetic measurements and thermal studies. Electrochemical study of the complexes is also reported. All the complexes are soluble to limited extent in common organic solvents but soluble to larger extent in DMF and DMSO and are non-electrolytes in DMF and DMSO. All these Schiff bases and their complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by MIC method. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties.

  11. Phosphate ester hydrolysis and DNA binding capacity of two new dinuclear Ni(II) complexes

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Xiao, W.; Mao, J. W.; Zhou, H.; Pan, Z. Q.

    2013-03-01

    Two new dinuclear Ni(II) complexes, [Ni2L1(OAc)2]ClO4 (1) and [Ni2L2(OAc)2] Br·0.5H2O (2) (where HL is the condensation product of 2,6-diformyl-4-X-phenol (X = CH3, Br) and N1-(2-aminoethyl)-N2-(4-nitrobenzyl)ethane-1,2-diamine), were synthesized and characterized. The coordination polyhedron of each metal ion in the complexes can be approximately described as a distorted octahedron. The Ni-Ni distances in 1 and 2 are 3.306 Å and 3.369 Å, respectively. The phosphate hydrolysis promoted by the complexes was examined using 4-nitrophenyl phosphate disodium salt hexahydrate (pNPP) as the substrate. The catalytic rate constants (kcat) are 1.29 × 10-5 s-1 for 1 and 0.47 × 10-5 s-1 for 2 at 25 °C in physiological pH condition. The binding activities of the complexes toward calf thymus (CT-DNA) were analyzed by spectroscopic and voltammetric methods, and the corresponding binding constants are 7.75 × 105 and 6.51 × 104 M-1 for 1 and 8.59 × 105 and 9.18 × 104 M-1 for 2, respectively. The linear Stern-Volmer quenching constants obtained in the fluorescent spectroscopic study of 1 and 2 are 0.7 × 103 and 1.5 × 103 M-1, respectively.

  12. Catalysis with Cu(II) (bpy) improves alkaline hydrogen peroxide pretreatment.

    PubMed

    Li, Zhenglun; Chen, Charles H; Liu, Tongjun; Mathrubootham, Vaidyanathan; Hegg, Eric L; Hodge, David B

    2013-04-01

    Copper(II) 2,2'-bipyridine (Cu(II) (bpy))-catalyzed alkaline hydrogen peroxide (AHP) pretreatment was performed on three biomass feedstocks including alkali pre-extracted switchgrass, silver birch, and a hybrid poplar cultivar. This catalytic approach was found to improve the subsequent enzymatic hydrolysis of plant cell wall polysaccharides to monosaccharides for all biomass types at alkaline pH relative to uncatalyzed pretreatment. The hybrid poplar exhibited the most significant improvement in enzymatic hydrolysis with monomeric sugar release and conversions more than doubling from 30% to 61% glucan conversion, while lignin solubilization was increased from 36.6% to 50.2% and hemicellulose solubilization was increased from 14.9% to 32.7%. It was found that Cu(II) (bpy)-catalyzed AHP pretreatment of cellulose resulted in significantly more depolymerization than uncatalyzed AHP pretreatment (78.4% vs. 49.4% decrease in estimated degree of polymerization) and that carboxyl content the cellulose was significantly increased as well (fivefold increase vs. twofold increase). Together, these results indicate that Cu(II) (bpy)-catalyzed AHP pretreatment represents a promising route to biomass deconstruction for bioenergy applications.

  13. Effect of formaldehyde on Cu(II) removal from synthetic complexed solutions by ion exchange.

    PubMed

    Juang, Ruey-Shin; Lin, Su-Hsia; Kao, Hsiang-Chien; Theng, Ming-Huei

    2005-06-01

    The effect of formaldehyde (HCHO) on the ion exchange of Cu(II) from an equimolar EDTA (ethylenediaminetetraacetic acid, H(4)L) solution with a strong-base Amberlite IRA-400 resin was studied. Experiments were conducted as a function of the initial concentration of Cu(II) (0.5-10 mM), solution pH (1.0-6.0), HCHO concentration (0-6 vol%), and temperature (15-35 degrees C). It was shown that the amount of exchange of Cu(II), which exists in the form of complexed anions CuL(2-), increased with increasing solution pH and reached a plateau at an equilibrium pH (pH(e)) of 3.5. However, the amount of exchange decreased with increasing HCHO concentration up to 3 vol% but then slightly decreased with a further increase in HCHO concentration. Such effect of added HCHO was determined by the following two factors: the competitive exchange of HCOO(-) anions and the enhanced exchange of Cu(I) in the form of complexed anions CuL(3-). The exchange isotherm obtained at a fixed pH(e) could be well described by the Langmuir equation. The isosteric enthalpy change for the present ion exchange process was also evaluated and discussed.

  14. Dual effects of curcumin on neuronal oxidative stress in the presence of Cu(II).

    PubMed

    Huang, Han-Chang; Lin, Chang-Jun; Liu, Wen-Juan; Jiang, Rui-Rui; Jiang, Zhao-Feng

    2011-07-01

    Alzheimer's disease (AD) is one of the most common neurodegenerative disorders. Elevated copper (Cu) ions are thought to link AD pathology. Curcumin is suggested to treat AD because of its high anti-oxidative activity and coordination to transitional metal ions. In this study, the protective effect of curcumin against the Cu(II)-induced oxidative damage was investigated in primary rat cortical neurons. The neuronal damage was assessed by morphological observation, cell viability, and oxidative stress level. The results showed that curcumin at low dosage protected primary cultured neurons from the 20 μM Cu(II)-induced damage. Low dosage of curcumin depressed oxidative stress levels exacerbated by Cu(II). However, high dosage of curcumin failed to decrease the Cu(II)-induced oxidative stress. When Cu(II) was presented in primary neurons, curcumin at high dosage resulted in chromosomal aberration and cell damage. These results suggest that curcumin, in a concentration-dependent manner, plays both anti-oxidative and pro-oxidative roles in primary neurons treated with Cu(II).

  15. Collagen/cellulose hydrogel beads reconstituted from ionic liquid solution for Cu(II) adsorption.

    PubMed

    Wang, Jilei; Wei, Ligang; Ma, Yingchong; Li, Kunlan; Li, Minghui; Yu, Yachen; Wang, Lei; Qiu, Huihui

    2013-10-15

    A novel adsorbent, biodegradable collagen/cellulose hydrogel beads (CCHBs), was prepared by reconstitution from a 1-butyl, 3-methylimidazolium chloride ([C4mim]Cl) solution. The adsorption properties of the CCHBs for Cu(II) ion removal from aqueous solutions were investigated and compared with those of cellulose hydrogel beads (CHBs). The CCHBs have a three-dimensional macroporous structure whose amino groups are believed to be the main active binding sites of Cu(II) ions. The equilibrium adsorption capacity (qe) of the CCHBs is greatly influenced by the collagen/cellulose mass ratio, and steeply increases until the collagen/cellulose mass ratio exceeds 2/1. The maximum adsorption is obtained at pH 6. The qe of Cu(II) ions increases with increased initial concentration of the solution. Based on Langmuir isotherms, the maximum adsorption capacity (qm) of CCHB3 (collagen/cellulose mass ratio of 3/1) is 1.06 mmol/g. The CCHBs maintain good adsorption properties after the fourth cycle of adsorption-desorption.

  16. Preparation, characterisation and study of in vitro biologically active azamacrocyclic Cu(II) dicarboxylate complexes

    NASA Astrophysics Data System (ADS)

    Antonijević-Nikolić, Mirjana; Antić-Stanković, Jelena; Tanasković, Sladjana B.; Korabik, Maria J.; Gojgić-Cvijović, Gordana; Vučković, Gordana

    2013-12-01

    New cationic Cu(II) complexes with N, N‧, N″, N″‧-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) and aliphatic dicarboxylic acids: pentanedioic (glutaric acid = glutH2), hexanedioic acid (adipic acid = adipH2) and decanedioic acid (sebacic acid = sebH2) of general formula [Cu4(L)(tpmc)2](ClO4)6·xH2O, L = glut, x = 2; L = adip, x = 7; L = seb, x = 6 were isolated. Their composition and charges are proposed based on elemental analyses and molar conductivity measurements. By the comparison of their UV-Vis, reflectance, FTIR and EPR spectral data, CV and SQUID magnetic measurements, with those for the complex with butanedioic acid (succinic acid = succH2) of known molecular structure and analysis of LC/MS spectra, geometry with two [Cu2tpmc]4+ units bridged by dicarboxylate dianion engaging all oxygens is proposed. Within units, Cu(II) ions are also bridged with N portion of cyclam ring. All four complexes were screened to in vitro antimicrobial and cytotoxic activity along with free primary and secondary ligands, Cu(II) salt and solvent controls. Detected antibacterial and cytotoxic activity for the complexes was enhanced in most cases than the corresponding controls.

  17. Cu(II) complexes in bacterial growth medium: electron spin resonance study

    NASA Astrophysics Data System (ADS)

    Jung, Katinka; Ristori, Sandra; Martini, Giacomo

    2000-02-01

    In this study we report a spectroscopic investigation on the structure and stability of Cu(II)-complexes that are formed in a minimum growth medium (MM), normally used for Bacillus subtilis cultures. As other transition metals, Cu(II) compounds are toxic to this bacterium and the toxicity depends on the Cu(II) concentration. MM contained NH 4+ ions and asparagine (asn) as the source of inorganic and organic nitrogen. Both ESR and electronic spectra demonstrated the very important role played by the amino acid asparagine in the coordinative behaviour of Cu(II). In particular, three different complexes were evidenced: Cu(H 2O) 62+; Cu(asn) + and Cu(asn) 2. The relative amount of these three species strongly depended on pH, on Cu:asn ratio and on the presence of the phosphate ions. They were identified and evaluated quantitatively by extensive simulation of the electron spin resonance (ESR) spectra recorded in different experimental conditions. The bis-complex was found to be more stable in MM than in an asparagine-containing water solution with the same Cu:asn ratio. A comparison of the spectroscopic results with microbiological investigations is also made.

  18. A new one-dimensional NiII coordination polymer with a two-dimensional supra­molecular architecture

    PubMed Central

    Zhong, Kai-Long

    2017-01-01

    A new one-dimensional NiII coordination polymer of 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene, namely catena-poly[[aqua­(sulfato-κO)hemi(μ-ethane-1,2-diol-κ2 O:O′)[μ3-1,3,5-tris­(1H-imidazol-1-ylmeth­yl)benzene-κ3 N 3,N 3′,N 3′′]nickel(II)] ethane-1,2-diol monosolvate monohydrate], {[Ni(SO4)(C18H18N6)(C2H6O2)0.5(H2O)]·C2H6O2·H2O}n, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The NiII cation is coordinated by three N atoms of three different 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene ligands, one O atom of an ethane-1,2-diol mol­ecule, by a sulfate anion and a water mol­ecule, forming a distorted octa­hedral NiN3O3 coordination geometry. The tripodal 1,3,5-tris­(imidazol-1-ylmeth­yl)benzene ligands link the NiII cations, generating metal–organic chains running along the [100] direction. Adjacent chains are further connected by O—H⋯O hydrogen bonds, resulting in a two-dimensional supermolecular architecture running parallel to the (001) plane. Another water mol­ecule and a second ethane-1,2-diol mol­ecule are non-coordinating and are linked to the coordinating sulfate ions via O—H⋯O hydrogen bonds. PMID:28217340

  19. Transition metal complexes of a new 15-membered [N5] penta-azamacrocyclic ligand with their spectral and anticancer studies

    NASA Astrophysics Data System (ADS)

    El-Boraey, Hanaa A.; Serag El-Din, Azza A.

    2014-11-01

    Novel penta-azamacrocyclic 15-membered [N5] ligand [L] i.e. 1,5,8,12-tetetraaza-3,4: 9,10-dibenzo-6-ethyl-7-methyl-1,12-(2,6-pyrido)cyclopentadecan-5,7 diene-2,11-dione and its transition metal complexes with Co(II), Ni(II), Cu(II), Ru(III) and Pd(II) have been synthesized and structurally characterized by elemental analysis, spectral, thermal as well as magnetic and molar conductivity measurements. On basis of IR, MS, UV-Vis 1H NMR and EPR spectral studies an octahedral geometry has been proposed for all complexes except Co(II), Cu(II) nitrate complexes and Pd(II) chloride complex that adopt tetrahedral, square pyramidal and square planar geometries, respectively. The antitumor activity of the synthesized ligand and some complexes against human breast cancer cell lines (MCF-7) and human hepatocarcinoma cell lines (HepG2) has been studied. The complexes (IC50 = 2.04-9.7, 2.5-3.7 μg/mL) showed potent antitumor activity comparable with their ligand (IC50 = 11.7, 3.45 μg/mL) against the above mentioned cell lines, respectively. The results evidently show that the activity of the ligand becomes more pronounced and significant when coordinated to the metal ion.

  20. Relative abundance of chemical forms of Cu(II) and Cd(II) on soybean roots as influenced by pH, cations and organic acids

    PubMed Central

    Zhou, Qin; Liu, Zhao-dong; Liu, Yuan; Jiang, Jun; Xu, Ren-kou

    2016-01-01

    Little information is available on chemical forms of heavy metals on integrate plant roots. KNO3 (1 M), 0.05M EDTA at pH6 and 0.01 M HCl were used sequentially to extract the exchangeable, complexed and precipitated forms of Cu(II) and Cd(II) from soybean roots and then to investigate chemical form distribution of Cu(II) and Cd(II) on soybean roots. Cu(II) and Cd(II) adsorbed on soybean roots were mainly exchangeable form, followed by complexed form, while their precipitated forms were very low under acidic conditions. Soybean roots had a higher adsorption affinity to Cu(II) than Cd(II), leading to higher toxic of Cu(II) than Cd(II). An increase in solution pH increased negative charge on soybean and thus increased exchangeable Cu(II) and Cd(II) on the roots. Ca2+, Mg2+ and NH4+ reduced exchangeable Cu(II) and Cd(II) levels on soybean roots and these cations showed greater effects on Cd(II) than Cu(II) due to greater adsorption affinity of the roots to Cu(II) than Cd(II). L-malic and citric acids decreased exchangeable and complexed Cu(II) on soybean roots. In conclusion, Cu(II) and Cd(II) mainly existed as exchangeable and complexed forms on soybean roots. Ca2+ and Mg2+ cations and citric and L-malic acids can potentially alleviate Cu(II) and Cd(II) toxicity to plants. PMID:27805020

  1. Relative abundance of chemical forms of Cu(II) and Cd(II) on soybean roots as influenced by pH, cations and organic acids

    NASA Astrophysics Data System (ADS)

    Zhou, Qin; Liu, Zhao-Dong; Liu, Yuan; Jiang, Jun; Xu, Ren-Kou

    2016-11-01

    Little information is available on chemical forms of heavy metals on integrate plant roots. KNO3 (1 M), 0.05M EDTA at pH6 and 0.01 M HCl were used sequentially to extract the exchangeable, complexed and precipitated forms of Cu(II) and Cd(II) from soybean roots and then to investigate chemical form distribution of Cu(II) and Cd(II) on soybean roots. Cu(II) and Cd(II) adsorbed on soybean roots were mainly exchangeable form, followed by complexed form, while their precipitated forms were very low under acidic conditions. Soybean roots had a higher adsorption affinity to Cu(II) than Cd(II), leading to higher toxic of Cu(II) than Cd(II). An increase in solution pH increased negative charge on soybean and thus increased exchangeable Cu(II) and Cd(II) on the roots. Ca2+, Mg2+ and NH4+ reduced exchangeable Cu(II) and Cd(II) levels on soybean roots and these cations showed greater effects on Cd(II) than Cu(II) due to greater adsorption affinity of the roots to Cu(II) than Cd(II). L-malic and citric acids decreased exchangeable and complexed Cu(II) on soybean roots. In conclusion, Cu(II) and Cd(II) mainly existed as exchangeable and complexed forms on soybean roots. Ca2+ and Mg2+ cations and citric and L-malic acids can potentially alleviate Cu(II) and Cd(II) toxicity to plants.

  2. Synthesis, biological and comparative DFT studies on Ni(II) complexes of NO and NOS donor ligands.

    PubMed

    Yousef, T A; El-Gammal, O A; Ahmed, Sara F; Abu El-Reash, G M

    2015-01-25

    Three new NOS donor ligands have been prepared by addition ethanolic suspension of 2-hydrazino-2-oxo-N-phenyl-acetamide to phenyl isocyanate (H2PAPS), phenyl isothiocyanate (H2PAPT) and benzoyl isothiocyanate (H2PABT). The Ni(II) complexes prepared from the chloride salt and characterized by conventional techniques. The isolated complexes were assigned the formulaes, [Ni2(PAPS)(H2O)2](H2O)2, [Ni(H2PAPT)Cl2(H2O)](H2O)2 and [(Ni)2(HPABT)2Cl2(H2O)2], respectively. The IR spectra of complexes shows that H2PAPS behaves as a binegative pentadentate via both CO of hydrazide moiety in keto and enol form, enolized CO of cyanate moiety and the CN (azomethine) groups of enolization. H2PAPT behaves as neutral tridentate via both CO of hydrazide moiety and CN (azomethine) group due to SH formation and finally H2PABT behaves as mononegative tetradentate via CO and enolized CO of hydrazide moiety, CO of benzoyl moiety and C=S groups. The experimental IR spectra of ligands are compared with those obtained theoretically from DFT calculations. Also, the bond lengths, bond angles, HOMO (Highest Occupied Molecular Orbitals), LUMO (Lowest Unoccupied Molecular Orbital) and dipole moments have been calculated. The calculated HOMO-LUMO energy gap reveals that charge transfer occurs within the molecule. The theoretical values of binding energies indicate the higher stability of complexes than of ligands. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. The antibacterial activities were also tested against B. Subtilis and E. coli bacteria. The free ligands showed a higher antibacterial effect than their Ni(II) complexes. The antitumor activities of the Ligands and their Ni(II) complexes have been evaluated against liver (HePG2) and breast (MCF-7) cancer cells. All ligands were found to display cytotoxicity that are better than that of Fluorouracil (5-FU), while Ni(II

  3. Synthesis, biological and comparative DFT studies on Ni(II) complexes of NO and NOS donor ligands

    NASA Astrophysics Data System (ADS)

    Yousef, T. A.; El-Gammal, O. A.; Ahmed, Sara F.; Abu El-Reash, G. M.

    2015-01-01

    Three new NOS donor ligands have been prepared by addition ethanolic suspension of 2-hydrazino-2-oxo-N-phenyl-acetamide to phenyl isocyanate (H2PAPS), phenyl isothiocyanate (H2PAPT) and benzoyl isothiocyanate (H2PABT). The Ni(II) complexes prepared from the chloride salt and characterized by conventional techniques. The isolated complexes were assigned the formulaes, [Ni2(PAPS)(H2O)2](H2O)2, [Ni(H2PAPT)Cl2(H2O)](H2O)2 and [(Ni)2(HPABT)2Cl2(H2O)2], respectively. The IR spectra of complexes shows that H2PAPS behaves as a binegative pentadentate via both CO of hydrazide moiety in keto and enol form, enolized CO of cyanate moiety and the CN (azomethine) groups of enolization. H2PAPT behaves as neutral tridentate via both CO of hydrazide moiety and CN (azomethine) group due to SH formation and finally H2PABT behaves as mononegative tetradentate via CO and enolized CO of hydrazide moiety, CO of benzoyl moiety and Cdbnd S groups. The experimental IR spectra of ligands are compared with those obtained theoretically from DFT calculations. Also, the bond lengths, bond angles, HOMO (Highest Occupied Molecular Orbitals), LUMO (Lowest Unoccupied Molecular Orbital) and dipole moments have been calculated. The calculated HOMO-LUMO energy gap reveals that charge transfer occurs within the molecule. The theoretical values of binding energies indicate the higher stability of complexes than of ligands. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. The antibacterial activities were also tested against B. Subtilis and E. coli bacteria. The free ligands showed a higher antibacterial effect than their Ni(II) complexes. The antitumor activities of the Ligands and their Ni(II) complexes have been evaluated against liver (HePG2) and breast (MCF-7) cancer cells. All ligands were found to display cytotoxicity that are better than that of Fluorouracil (5-FU), while Ni(II

  4. Immobilization of Pb(II), Cd(II) and Ni(II) ions on kaolinite and montmorillonite surfaces from aqueous medium.

    PubMed

    Sen Gupta, Susmita; Bhattacharyya, Krishna G

    2008-04-01

    The present study investigates the immobilization of Pb(II), Cd(II) and Ni(II) on clays (kaolinite and montmorillonite) in aqueous medium through the process of adsorption under a set of variables (concentration of metal ion, amount of clay, pH, time and temperature of interaction). Increasing pH favours the removal of metal ions till they are precipitated as the insoluble hydroxides. The uptake is rapid with maximum adsorption being observed within 180 min for Pb(II) and Ni(II) and 240 min for Cd(II). A number of available models like the Lagergren pseudo first-order kinetics, second-order kinetics, Elovich equation, liquid film diffusion and intra-particle diffusion are utilized to evaluate the kinetics and the mechanism of the immobilization interactions. Two isotherm equations due to Langmuir and Freundlich showed good fits with the experimental data. Kaolinite and montmorillonite have considerable Langmuir monolayer capacity with respect to Pb(II), Cd(II) and Ni(II), the values being in the range of 6.8-11.5mg/g (kaolinite) and 21.1-31.1mg/g (montmorillonite). The Freundlich adsorption capacity follows a similar order. The thermodynamics of the immobilization process indicates the same to be exothermic with Pb(II) and Ni(II), but endothermic with Cd(II). The interactions with Pb(II) and Ni(II) are accompanied by decrease in entropy and Gibbs energy while the endothermic immobilization of Cd(II) is supported by an increase in entropy and an appreciable decrease in Gibbs energy. The results have established good potentiality for kaolinite and montmorillonite to remove heavy metals like Pb(II), Cd(II) and Ni(II) from aqueous medium through adsorption-mediated immobilization.

  5. Adsorption of Ni(II) and Cd(II) from water by novel chelating sponge and the effect of alkali-earth metal ions on the adsorption.

    PubMed

    Cheng, Cheng; Wang, Jinnan; Yang, Xin; Li, Aimin; Philippe, Corvini

    2014-01-15

    Novel chelating sponge (PVA-M-H) was prepared with polyvinyl alcohol by graft polymerization and nucleophilic substitution. E.A, SEM, FT-IR, (13)CNMR, and XPS analyses were used to characterize PVA-M-H. The equilibrium adsorption capacities of PVA-M-H for Ni(II) and Cd(II) were 65.39 and 125.11mgg(-1), respectively. Within the range of 278-308K, the adsorption enthalpy changes of Ni(II) and Cd(II) on PVA-M-H were about 36.39-37.72kJmol(-1), and the free energy were about -13.27 to -1.7kJmol(-1). Both pseudo-first- and -second-order equations fit the adsorption kinetic curves well, and the initial adsorption rates of Ni(II) and Cd(II) onto PVA-M-H were 17.83 and 34.81mg (gmin)(-1), respectively. Although the presence of alkali-earth metal ions in solution decreased Ni(II) and Cd(II) removal, PVA-M-H still retained more than 60 and 80% of its adsorption capacity even as the concentration of Ca(2+) and Mg(2+) was up to 10mmolL(-1), respectively. Both 0.1M HCl and 0.1M EDTA solution could desorb Ni(II) and Cd(II) from PVA-M-H effectively, and the adsorption capacity of PVA-M-H for Ni(II) and Cd(II) could still maintain more than 90% level without any obvious decrease at the fifth cycle.

  6. Kinetic and thermodynamic studies of the Co(II) and Ni(II) ions removal from aqueous solutions by Ca-Mg phosphates.

    PubMed

    Ivanets, A I; Srivastava, V; Kitikova, N V; Shashkova, I L; Sillanpää, M

    2017-03-01

    The aim of this work was to study the sorption kinetics and thermodynamics of Co(II) and Ni(II) from aqueous solutions by sorbents on the basis of hydrogen (PD-1) and tertiary (PD-2) Ca-Mg phosphates depending on the solution temperature and sorbents chemical composition. Kinetic studies of adsorption of Co(II) and Ni(II) ions onto samples of phosphate sorbents were performed in batch experiment at the temperatures 288, 303, 318 and 333 K. The sorbent dose was fixed at 10 g L(-1), initial pH value 2.6, and contact time varied from 5 to 600 min. The kinetics of Co(II) and Ni(II) adsorption were analyzed by using pseudo-first order, pseudo-second order and intraparticle diffusion models. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for the sorption of Co(II) and Ni(II) were determined using the Gibbs-Helmholtz equation. The calculated kinetic parameters and corresponding correlation coefficients revealed that Co(II) and Ni(II) uptake process followed the pseudo-second order rate expression. Thermodynamic studies confirmed the spontaneous and endothermic nature of removal process which indicate that sorption of Co(II) and Ni(II) ions onto both phosphate sorbents is favoured at higher temperatures and has the chemisorptive mechanism. The data thus obtained would be useful for practical application of the low cost and highly effective Ca-Mg phosphate sorbents.

  7. Synthesis, DNA binding and complex formation reactions of 3-amino-5,6-dimethyl-1,2,4-triazine with Pd(II) and some selected biorelevant ligands

    NASA Astrophysics Data System (ADS)

    Shoukry, Azza A.; Alghanmi, Reem M.

    2015-03-01

    With the purpose of studying the binding behavior of Pd(II) complexes with DNA as the main biological target, and their ability to penetrate reasonably into tumour cells and destroy their replication ability, Pd(ADT)Cl2 complex was synthesized and characterized, where ADT is 3-amino-5,6-dimethyl-1,2,4-triazine. Stoichiometry and stability constants of the complexes formed between various biologically relevant ligands (amino acids, amides, DNA constituents, and dicarboxylic acids) and [Pd(ADT)(H2O)2]2+ were investigated at 25 °C and at constant 0.1 mol dm-3 ionic strength. The concentration distribution diagrams of the various species formed are evaluated. Further investigation of the binding properties of the diaqua complex [Pd(ADT)(H2O)2]2+ with calf thymus DNA (CT-DNA) was investigated by UV-vis spectroscopy. The intrinsic binding constants (Kb) calculated from UV-vis absorption studies was calculated to be 2.00 × 103 mol dm-3. The calculated (Kb) value was found to be of lower magnitude than that of the classical intercalator EB (Ethidium bromide) (Kb = 1.23(±0.07) × 105 mol dm-3) suggesting an electrostatic and/or groove binding mode for the interaction with CT-DNA. Thermal denaturation has been systematically studied by spectrophotometric method and the calculated ΔTm was nearly 5 °C, supporting the electrostatic and/or groove binding mode for the interaction between the complex and CT-DNA

  8. Al(III), Pd(II), and Zn(II) phthalocyanines for inactivation of dental pathogen Aggregatibacter actinomycetemcomitans as planktonic and biofilm-cultures

    NASA Astrophysics Data System (ADS)

    Kussovski, V.; Mantareva, V.; Angelov, I.; Avramov, L.; Popova, E.; Dimitrov, S.

    2012-06-01

    The Gram-negative, oral bacterium Aggregatibacter actinomycetemcomitans has been implicated as the causative agent of several forms of periodontal disease in humans. The new periodontal disease treatments are emergence in order to prevent infection progression. Antimicrobial photodynamic therapy (a-PDT) can be a useful tool for this purpose. It involves the use of light of specific wavelength to activate a nontoxic photosensitizing agent in the presence of oxygen for eradication of target cells, and appears effective in photoinactivation of microorganisms. The phthalocyanine metal complexes of Pd(II)- (PdPcC) and Al(III)- (AlPc1) were evaluated as photodynamic sensitizers towards a dental pathogen A. actinomycetemcomitans in comparison to the known methylpyridyloxy-substituted Zn(II) phthalocyanine (ZnPcMe). The planktonic and biofilm-cultivated species of A. actinomycetemcomitans were treated. The photophysical results showed intensive and far-red absorbance with high tendency of aggregation for Pd(II)-phthalocyanine. The dark toxicities of both photosensitizers were negligible at concentrations used (< 0.5 log decrease of viable cells). The photodynamic response for planktonic cultured bacteria was full photoinactivation after a-PDT with ZnPcMe. In case of the newly studied complexes, the effect was lower for PdPcC (4 log) as well as for AlPc1 (1.5-2 log). As it is known the bacterial biofilms were more resistant to a-PDT, which was confirmed for A. actinomycetemcomitans biofilms with 3 log reductions of viable cells after treatment with ZnPcMe and approximately 1 log reduction of biofilms after PdPcC and AlPc1. The initial results suggest that a-PDT can be useful for effective inactivation of dental pathogen A. actinomycetemcomitans.

  9. Complexes of Pd(II) and Pt(II) with 9-Aminoacridine: Reactions with DNA and Study of Their Antiproliferative Activity

    PubMed Central

    Riera, X.; Moreno, V.; Ciudad, C. J.; Noe, V.; Font-Bardía, M.; Solans, X.

    2007-01-01

    Four new metal complexes {M = Pd(II) or Pt(II)} containing the ligand 9-aminoacridine (9AA) were prepared. The compounds were characterized by FT-IR and 1H, 13C, and 195Pt NMR spectroscopies. Crystal structure of the palladium complex of formulae [Pd(9AA)(μ-Cl)]2 · 2DMF was determined by X-ray diffraction. Two 9-acridine molecules in the imine form bind symmetrically to the metal ions in a bidentate fashion through the imine nitrogen atom and the C(1) atom of the aminoacridine closing a new five-membered ring. By reaction with phosphine or pyridine, the Cl bridges broke and compounds with general formulae [Pd(9AA)Cl(L)] (where L = PPh3 or py) were formed. A mononuclear complex of platinum of formulae [Pt(9AA)Cl(DMSO)] was also obtained by direct reaction of 9-aminoacridine and the complex [PtCl2(DMSO2]. The capacity of the compounds to modify the secondary and tertiary structures of DNA was evaluated by means of circular dichroism and electrophoretic mobility. Both palladium and platinum compounds proved active in the modification of both the secondary and tertiary DNA structures. AFM images showed noticeable modifications of the morphology of the plasmid pBR322 DNA by the compounds probably due to the intercalation of the complexes between base pairs of the DNA molecule. Finally, the palladium complex was tested for antiproliferative activity against three different human tumor cell lines. The results suggest that the palladium complex of formula [Pd(9AA)(μ-Cl)]2 has significant antiproliferative activity, although it is less active than cisplatin. PMID:18364995

  10. Low-dimensional compounds containing bioactive ligands. V: Synthesis and characterization of novel anticancer Pd(II) ionic compounds with quinolin-8-ol halogen derivatives.

    PubMed

    Vranec, Peter; Potočňák, Ivan; Sabolová, Danica; Farkasová, Veronika; Ipóthová, Zuzana; Pisarčíková, Jana; Paulíková, Helena

    2014-02-01

    Three novel palladium(II) complexes, NH2(CH3)2[PdCl2(CQ)] (1) (CQ=5-chloro-7-iodo-quinolin-8-ol), NH2(CH3)2[PdCl2(dClQ)] (2) (dClQ=5,7-dichloro-quinolin-8-ol) and NH2(CH3)2[PdCl2(dBrQ)] (3) (dBrQ=5,7-dibromo-quinolin-8-ol) have been prepared and characterized. Their structures contain square-planar [PdCl2(XQ)](-) complex anions in which deprotonated XQ ligands are coordinated to the Pd atoms via the pyridine nitrogen and the phenolato oxygen atoms, other two cis-positions are occupied by two chlorido ligands. Negative charges of these anions are balanced by uncoordinated dimethylammonium cations. Coordination of the XQ ligands to Pd(II) atom was confirmed by the differences in the stretching ν(OH) and ν(CN) vibrations in the IR spectra of ligands and prepared complexes while bands of aliphatic CH and NH stretching vibrations observed in the spectra of 1-3 confirm the presence of dimethylammonium cations in the complexes. The binding of complexes 1-3 to calf thymus DNA was investigated using UV-visible and fluorescence emission spectrophotometry. The fluorescence spectral results indicate that the complexes can bind to DNA through an intercalative mode. The Stern-Volmer quenching constants obtained from the linear quenching plot are in the 1.04 × 10(4) to 4.35 × 10(4) M(-1) range. The complexes exhibit significant anticancer activity tested on A2780 cells and cisplatin resistant cell line A2780/CP.

  11. Interaction between glutathione and Cu(II) in the vicinity of nucleic acids.

    PubMed Central

    Prütz, W A

    1994-01-01

    GSH interacts with Cu(II) in the vicinity of DNA (pH approximately 7) to form the DNA-Cu(I) complex, which can be quantified by characteristic absorption changes [e.g. delta epsilon 295 = 4516 cm-1.M-1 Cu(I)]. Under initial conditions of Cu(II)/GSH >> 1 and DNA(base)/Cu(II) >> 5, the stoichiometry is 1 DNA-Cu(I) per SH group (also for other thiols). Stopped-flow kinetics show that the complex is formed with half-lives of 1-30 s, depending on the environment, but independent of O2. DNA-Cu(I) generation is much slower, less efficient, and O2-dependent at Cu(II)/GSH < 1, or when GSH interacts with Cu(II) before the addition of DNA. Interaction of GSH with Cu(II) in the presence of DNA [at Cu(II)/GSH > 1] leads to DNA-associated transients, probably DNA-GS(-)-Cu(I); DNA-Cu(I) formation under these conditions is proposed to occur by ligand exchange: DNA-GS(-)-Cu(I)+Cu(II)<-->DNA-Cu(I)+GS(-)-Cu(II). There is no evidence for generation of free thiyl radicals (GS.) on reaction of Cu(II) with GSH. Formation of DNA-Cu(I) is, in our opinion, a primary step involved in DNA-strand cleavage by GSH in the presence of Cu(II) [Reed and Douglas (1991) Biochem. J. 275, 601-608]. In this context the question of the pro-oxidative and/or antioxidative activity of GSH, when combined with copper, is discussed. GSH also generates Cu(I) complexes with other nucleic acids. An updated order of affinities of various nucleic acids for Cu(I) is presented. Cu(I) exhibits a high preference for alternating dG-dC sequences and might even be a Z-DNA inducer. The poly(C)-Cu(I) complex seems to form a base-paired structure at pH approximately 7, as demonstrated by intercalation of ethidium bromide. PMID:8092988

  12. Coadsorption of ciprofloxacin and Cu(II) on montmorillonite and kaolinite as affected by solution pH.

    PubMed

    Pei, Zhiguo; Shan, Xiao-Quan; Kong, Jingjing; Wen, Bei; Owens, Gary

    2010-02-01

    The coadsorption of ciprofloxacin (Cip) and Cu(II) on montmorillonite and kaolinite was studied between pH 4.0 and 9.5. At pH < 5.0, Cu(2+), Cip(+) and [Cu(II)(Cip(+/-))](2+) were the main species in solution. Between pH 5.0-7.0 [Cu(II)(Cip(+/-))](2+) was the dominant complex species. Above pH 8.0 [Cu(II)(Cip(-))(2)](0) precipitated. The presence of Cu(II) exerted no effect on the Cip sorption onto montmorillonite at low pH, whereas it increased Cip sorption on montmorillonite at pH > 6.0 due to the stronger affinity of Cip-Cu(II) complexes compared to sole Cip(-) or Cip(+/-), or Cip sorption via a Cu(II) bridge increased. In contrast, Cip increased Cu(II) adsorption on montmorillonite at pH < 7.0, whereas it decreased the adsorption of Cu(II) on kaolinite at pH 6.0-8.0. Cip was sorbed onto the kaolinite surface via interaction of carboxyl groups over the entire pH range. At pH 4.0-4.7, Cip(+) sorption onto kaolinite's positively charged surface was more favorable than sorption of Cip-Cu(II) complexes. Batch experiments and FTIR analyses indicated that the coordination between Cip(+/-), Cip(-) and Cu(II) were most likely present on kaolinite surface at pH 7.0. At pH > 8.0, Cu(OH)(2) (s) and [Cu(II)(Cip(-))(2)](0) precipitated out of solution or on the montmorillonite or kaolinite surface, which was not considered evidence for either the sorption of Cip or the adsorption of Cu(II).

  13. Arene C(sp(2))-H Metalation at Ni(II) Modeled with a Reactive PONCPh Ligand.

    PubMed

    Jongbloed, Linda S; García-López, Diego; van Heck, Richard; Siegler, Maxime A; Carbó, Jorge J; van der Vlugt, Jarl Ivar

    2016-08-15

    Coordination of the reactive phosphinitopyridylphenyl PONCPh ligand L(H) to NiBr2 initially yields paramagnetic brown NiBr2(L(H)) (1), but addition of triethylamine results in fast and facile cyclometalation at Ni(II), giving NiBr(κ(3)-P,N,C-L) (2) as well-defined species. This is a rare example of direct cyclometalation at Ni(II) from a C-H bond in a ligand structure other than encumbering ligands (e.g., ECE pincers). Diamagnetic yellow complex 2 reacts instantaneously with HBF4 to give purple [NiBr(κ(3)-P,N-L(H))]BF4 (3). A very unusual (an)agostic Ni(CPh-H) interaction in the solid-state structure of 3 was unequivocally demonstrated using single-crystal X-ray crystallography and was interpreted by density functional theory calculations (quantum theory of atoms in molecules and electron localization function analysis). These compounds may be viewed as models for key intermediates in the Ni-catalyzed C-H functionalization of arenes.

  14. Syntheses, structural characterization, luminescence and optical studies of Ni(II) and Zn(II) complexes containing salophen ligand

    NASA Astrophysics Data System (ADS)

    More, M. S.; Pawal, S. B.; Lolage, S. R.; Chavan, S. S.

    2017-01-01

    Some Ni(II) (1a-d) and Zn(II) (2a-d) salophen complexes were prepared by the treatment of 5-bromosalicylaldehyde, 5-(trimethylsilylethynyl)salicylaldehyde, 5-(4-nitrophenyl)ethynylsalicylaldehyde or 5-(4-methoxyphenyl)ethynylsalicylaldehyde with nickel acetate or zinc acetate followed by addition of 2,3-diamino-5-bromopyridine. All complexes were characterized by elemental analyses, IR, 1H NMR and mass spectral studies. X-ray powder diffraction of representative complexes 1c and 2b and SEM studies of 1b and 2d are used to elucidate the crystal structure and morphology of the complexes. The electrochemical behavior reveals that the redox responses of Ni(II) complexes shifted to more negative potential in order to increase the π-conjugation in the complexes. Room temperature luminescence is observed for all complexes corresponding to π→π* ILCT transition with some MLCT character in DMF and is finely tuned by the degree of extended π-conjugation and variation of the substituent group with different electronic effects in the complexes. The second harmonic generation (SHG) efficiency of the complexes was screened by Kurtz-powder technique indicating that all complexes possesses promising potential for the application as a useful nonlinear optical material.

  15. Immobilization of polyethylenimine nanoclusters onto a cation exchange resin through self-crosslinking for selective Cu(II) removal.

    PubMed

    Chen, Yiliang; Pan, Bingcai; Zhang, Shujuan; Li, Haiyan; Lv, Lu; Zhang, Weiming

    2011-06-15

    Donnan membrane principle provides great opportunities for development of highly efficient adsorbents for toxic metals abatement. Based on the principle we prepared a new composite adsorbent by immobilizing polyethylenimine (PEI) nanoclusters within a macroporous cation exchanger D001 through self-crosslinking by glutaraldehyde upon Cu(II)-template process. Negligible PEI loss was observed from the resultant composite adsorbent D001-PEI-GA to solution of pHs 1-12. Increasing solution pH from 1 to 6 results in more favorable Cu(II) retention by D001-PEI-GA, and Cu(II) adsorption onto D001-PEI-GA follows the pseudo-second-order kinetic model well. Compared to D001, D001-PEI-GA displays more preferable Cu(II) sequestration in the presence of co-ions Mg(2+), Ca(2+), Sr(2+) at higher levels. Fixed-bed adsorption of a synthetic solution containing Cu(II) and other co-ions showed that Cu(II) sequestration on D001-PEI-GA could result in its conspicuous decrease from 5mg/L to below 0.01 mg/L with the treatment volume as high as 630 BV per run, while that for D001 was only ∼ 85 BV. Also, the spent composite adsorbent can be readily regenerated by HCl (0.3M)-NaCl (0.5M) binary solution for repeated use with negligible capacity loss.

  16. Alginate-immobilized bentonite clay: adsorption efficacy and reusability for Cu(II) removal from aqueous solution.

    PubMed

    Tan, Wei Shang; Ting, Adeline Su Yien

    2014-05-01

    This study evaluated the use of alginate-immobilized bentonite to remove Cu(II) as an alternative to mitigate clogging problems. The adsorption efficacy (under the influence of time, pH and initial Cu(II) concentration) and reusability of immobilized-bentonite (1% w/v bentonite) was tested against plain alginate beads. Results revealed that immobilized bentonite demonstrated significantly higher sorption efficacy compared to plain alginate beads with 114.70 and 94.04 mg Cu(II) adsorbed g(-1) adsorbent, respectively. Both sorbents were comparable in other aspects where sorption equilibrium was achieved within 6 h, with optimum pH between pH 4 and 5 for adsorption, displayed maximum adsorption capacity at initial Cu(II) concentrations of 400 mg l(-1), and demonstrated excellent reusability potential with desorption greater than 90% throughout three consecutive adsorption-desorption cycles. Both sorbents also conformed to Langmuir isotherm and pseudo-second order kinetic model. Immobilized bentonite is therefore recommended for use in water treatments to remove Cu(II) without clogging the system.

  17. Removal of Cu(II) in aqueous media by biosorption using water hyacinth roots as a biosorbent material.

    PubMed

    Zheng, Jia-Chuan; Feng, Hui-Min; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Ding, Yan-Wei; Yu, Han-Qing

    2009-11-15

    Water hyacinth roots were employed as a biosorbent to remove Cu(II) in aqueous media. Nitrogen adsorption/desorption analysis revealed that the biosorbent was mesoporous with a relatively small surface area. Equilibrium biosorption isotherms showed that the water hyacinth roots possessed a high affinity and sorption capacity for Cu(II) with a monolayer sorption capacity of 22.7 mg g(-1) at initial pH 5.5. Kinetics study at different temperatures revealed that the sorption was a rapid and endothermic process. The activation energy for Cu(II) sorption was estimated to be 30.8 kJ mol(-1), which is typical of activated chemisorption processes. The sorption mechanism was investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, effect of pH and calcium release. These analyses suggested that the biosorption mainly involved the ion exchange of Cu(II) with cations and complex formation with functional groups on the surface of the roots. All the results showed that water hyacinth roots are an alternative low-cost biosorbent for the removal of Cu(II) from aqueous media.

  18. Synthesis, Characterization and Antimicrobial Activity of d8-10 Metal Complexes of some 2-Substituted-1H-Benzimidazoles

    PubMed Central

    Tavman, Aydin; Ötük, Gülten

    1999-01-01

    The metal complexes of nine 2-substituted-1H-benzimidazoles (I-IX) with Ni(II), Pd(II), Cu(II), Ag(I), Zn(II) salts were synthesized. The compounds were characterized by melting point, analytical data, IR spectroscopy and magnetic susceptibility. The antimicrobial activity of the compounds was determined by the disk diffusion method in Mueller-Hinton Agar on Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis, Candida albicans ATCC 10231. Cu(II)and Ag(I)complexes of II, III and IV showed considerable activity against S. aureus, S. epidermidis, Ps. aeruginosa, S. typhi, Sh. flexneri and C. albicans microorganisms, the ligands themselves having no effect. PMID:18472907

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  20. Physicochemical studies and biological evaluation on (E)-3-(2-(1-(2-hydroxyphenyl)hydrazinyl)-3-oxo-N-(thiazol-2yl)propanamide complexes

    NASA Astrophysics Data System (ADS)

    Ibrahim, K. M.; Zaky, R. R.; Gomaa, E. A.; Abd El-Hady, M. N.

    2013-04-01

    Hydrazone complexes of Co(II), Ni(II), Cu(II), Pd(II), Cd(II), Zn(II) and U(VI)O2 with (E)-3-(2-(1-(2-hydroxyphenyl)hydrazinyl)-3-oxo-N-(thiazol-2yl)propanamide (H2o-HAH) have been synthesized. The complex structure has been elucidated by analysis (elemental and thermal), spectroscopy (1H NMR, 13C NMR, IR, UV-visible, ESR, MS) and physical measurements (magnetic susceptibility and molar conductance). The kinetic and thermodynamic parameters for the different decomposition steps of some complexes have been calculated using the Coats-Redfern equation. Also, the association and formation constants of Co(II) ion in absolute ethanol solutions at 294.15 K have been calculated by using electrical conductance. Moreover, the ligand and its complexes have been screened for their antibacterial (Escherichia coli and Clostridium sp.) and antifungal activities (Aspergillus sp. and Stemphylium sp.) by MIC method.

  1. Spectrophotometric determination of molybdenum by extraction of its thiosulphate complex.

    PubMed

    Yatirajam, V; Ram, J

    1974-12-01

    A simple and rapid spectrophotometric determination of molybdenum is described. The molybdenum thiosulphate complex is extracted into isoamyl alcohol from 1.0-1.5M hydrochloric acid containing 36-40 mg of Na(2)S(2)O(3).5H(2)O per ml. The absorbance at lambda(max) = 475 nm obeys Beer's law over the range 0-32 microg of Mo per ml of solvent phase. Up to 5 mg/ml of Ti(IV), V(V), Cr(VI), Fe(III), Co(II), Ni(II), U(VI), W(VI), Sb(III), 1 mg/ml of Cu(II), Sn(II), Bi(V) and 10 microg/ml of Pt(IV) and Pd(II) do not interfere. Large amounts of complexing agents interfere. The method has been applied to analysis of synthetic and industrial samples.

  2. Catalytic determination of Pb(II) in the presence of Cu(II).

    PubMed

    Rustoiu-Csavdari, A; Bâldea, S; Mihai, D

    2002-09-01

    A kinetic method is presented to determine micro-molar amounts of Pb(II) from various river and wastewater samples, in the presence of trace copper. The procedure is based on the catalytic effect of both species on the oxidation of mercaptosuccinic acid by chromate in acidic media. The extent of the reaction is followed spectrophotometrically at 420 nm and pseudo-first-order rate coefficients of the rate-determining step are determined as a function of catalyst concentrations. The optimum operating conditions (ionic strength, temperature, and concentration of reagents) regarding sensitivity towards lead were established. Interference by several ionic species has been studied. The effect of Fe(III), the only severe interferent, is suppressed by complexation with 1,10-phenantroline. The bi-component calibration model employs an artificial neural network to compute the Pb(II) concentration from a k(obsd) value and the a priori-known Cu(II) concentration of the sample. Working concentration ranges are 20-2160 micro g L(-1) for Pb(II) and 80-650 micro g L(-1) for Cu(II), respectively. Detection limits are 20 micro g L(-1) Pb(II) and 80 micro g L(-1) Cu(II), respectively. The relative standard deviations (3 measurements) for four different testing points are lower than 2.5%. The method was applied to samples of river and wastewater of the mining region of Baia-Mare, Northern Romania. The results were compared to those obtained by an officially standardized AAS method. Good agreement was achieved. The method is inexpensive, fairly rapid, and sensitive. Its working range covers the exact range of concentrations usually encountered in the mentioned geographic area.

  3. Fluorescent probe based subcellular distribution of Cu(II) ions in living electrotrophs isolated from Cu(II)-reduced biocathodes of microbial fuel cells.

    PubMed

    Tao, Ye; Xue, Hua; Huang, Liping; Zhou, Peng; Yang, Wei; Quan, Xie; Yuan, Jinxiu

    2017-02-01

    Based on the four indigenous electrotrophs (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) isolated from well adapted Cu(II)-reduced biocathodes of microbial fuel cells (MFCs), a rhodamine based Cu(II) fluorescent probe was used to imaginably and quantitatively track subcellular Cu(II) ions in these electrotrophs. Cathodic electrons led to more Cu(II) ions (14.3-30.1%) in the intracellular sites at operation time of 2-3h with Cu(II) removal rates of 2.90-3.64mg/Lh whereas the absence of cathodic electrons prolonged the appearance of more Cu(II) ions (16.6-22.5%) to 5h with Cu(II) removal rates of 1.96-2.28mg/Lh. This study illustrates that cathodic electrons directed more Cu(II) ions for quicker entrance into the electrotrophic cytoplasm, and gives an alternative approach for developing imaging and functionally tracking Cu(II) ions in the electrotrophs of MFCs.

  4. Spectroscopic investigation of bis-appended 1,2,3-triazole probe for the detection of Cu(II) ion

    NASA Astrophysics Data System (ADS)

    Ghosh, Debanjana; Rhodes, Shannon; Winder, Domonique; Atkinson, Austin; Gibson, Jaclyn; Ming, Weihua; Padgett, Clifford; Landge, Shainaz; Aiken, Karelle

    2017-04-01

    A novel bis-1,4-disubstituted-1,2,3-triazole chemosensor, accessed with "Click Chemistry", was probed for its recognition of metal ions. The interaction of the sensor with various cation analytes was investigated by 1H-NMR, UV-Vis absorption and fluorescence spectroscopy. The bis-triazole is selective for Cu(II) with a detection limit in the micromolar concentration range and a clear to yellow colorimetric response that is exclusive to that ion is observed. The stoichiometry of probe to Cu(II), 2:1, was determined with Job's plots based on titration studies using UV-absorption and 1H-NMR spectroscopy. Computational and spectroscopic investigations revealed that the sensor binds to Cu(II) via its triazole units.

  5. Isostructural Pd(II) and Pt(II) pyrophosphato complexes: polymorphism and unusual bond character in d8-d8 systems.

    PubMed

    Marino, Nadia; Fazen, Christopher H; Blakemore, James D; Incarvito, Christopher D; Hazari, Nilay; Doyle, Robert P

    2011-03-21

    Isostructural, "clamshell"-like, neutral dimeric pyrophosphato complexes of general formula {[M(bipy)](2)(μ-P(2)O(7))} [M = Pd(II) (1) or Pt(II) (2)] were synthesized and studied through single-crystal X-ray diffraction, IR, (31)P NMR spectroscopy, and MALDI-TOF mass spectrometry. Compound 1 was synthesized through the reaction of palladium(II) acetate, 2,2'-bipyridine (bipy), and sodium pyrophosphate (Na(4)P(2)O(7)) in water. Compound 2 was prepared through two different routes. The first involved the reaction of the Pt(IV) precursor Na(2)PtCl(6), bipy, and Na(4)P(2)O(7) in water, followed by reduction in DMF. The second involved the reaction of the Pt(II) precursor K(2)PtCl(4), bipy, and Na(4)P(2)O(7) in water. Both complexes crystallize in the monoclinic chiral space group Cc as hexahydrates, 1·6H(2)O (1a, yellow crystals) and 2·6H(2)O (2a, orange crystals), and exhibit a zigzag chain-like supramolecular packing arrangement with short and long intra/intermolecular metal-metal distances [3.0366(3)/4.5401(3) Å in 1a; 3.0522(3)/4.5609(3) Å in 2a]. A second crystalline phase of the Pt species was also isolated, with formula 2·3.5H(2)O (2b, deep green crystals), characterized by a dimer-of-dimers (pseudo-tetramer) structural submotif. Green crystals of 2b could be irreversibly converted to the orange form 2a by exposure to air or water, without retention of crystallinity, while a partial, reversible crystal-to-crystal transformation occurred when 2a was dried in vacuo. (31)P NMR spectra recorded for both 1 and 2 at various pHs revealed the occurrence of a fluxional protonated/deprotonated system in solution, which was interpreted as being composed, in the protonated form, of [HO=PO(3)](+) (P(α)) and O=PO(3) (P(β)) pyrophosphate subunits. Compounds 1 and 2 exhibited two successive one-electron oxidations, mostly irreversible in nature; however, a dependence upon pH was observed for 1, with oxidation only occurring in strongly basic conditions. Density

  6. Preparation and characterization of chitosan-clay nanocomposites for the removal of Cu(II) from aqueous solution.

    PubMed

    Azzam, Eid M S; Eshaq, Gh; Rabie, A M; Bakr, A A; Abd-Elaal, Ali A; El Metwally, A E; Tawfik, Salah M

    2016-08-01

    In the present study, chitosan assembled on gold and silver nanoparticles were prepared and characterized by UV-vis, TEM, EDX and DLS techniques. The nanocomposites chitosan (Ch)/clay, chitosan (Ch)/AgNPs/clay and chitosan (Ch)/AuNPs/clay were prepared by solution mixing method and characterized by FTIR, XRD, and SEM techniques. The adsorption of copper(II) ions onto the prepared hybrid composites from an aqueous solution using batch adsorption was examined. The results showed that benefiting from the surface property of clay, the abundant amino and hydroxyl functional groups of chitosan, the adsorbent provides adequate and versatile adsorption for the Cu(II) ions under investigation. The batch adsorption experiments showed that the adsorption of the Cu(II) is considerably dependent on pH of milieu, the amount of adsorbent, and contact time. Batch adsorption studies revealed that the adsorption capacity of Cu(II) increased with increase in initial concentration and contact time with optimum pH in the range around neutral. The maximum uptake of Cu(II) ions by (Ch)/AgNPs/clay composite was found to be 181.5mg/g. The adsorption efficiency of Cu(II) ions by prepared (Ch)/AgNPs/clay and (Ch)/AuNPs/clay is bigger than that the individual chitosan (Ch)/clay composite which clarifies the role of metal nanoparticles in enhancement the adsorption characters. The study suggests that the (Ch)/AgNPs/clay hybrid composite is a promising nano-adsorbent for the removal of Cu(II) ions from aqueous solution.

  7. The role of Cu(II) in the reduction of N-nitrosodimethylamine with iron and zinc.

    PubMed

    Han, Ying; Chen, Zhong-Lin; Shen, Ji-Min; Wang, Ji-He; Li, Wei-Wei; Li, Jun; Wang, Bin-Yuan; Tong, Li-Na

    2017-01-01

    The role of Cu(II) in the reduction of N-nitrosodimethylamine (NDMA) with zero-valent metals was investigated by determining the effects of Cu(II) on the removal, kinetics, products, and mechanism. NDMA removal was enhanced, and all reactions followed a pseudo-first-order kinetic model except for the Fe and Fe/0.1 mM Cu(II) systems. The iron mass-normalized pseudo-first-order rate constants (kMFe) increased with the Cu(II) concentration. The zinc mass-normalized pseudo-first-order rate constants (kMZn) were identical to those with the Cu(II) concentrations from 0.1 mM to 1.0 mM and were higher with 2.0 mM Cu(II). The types of products detected were unchanged. Some unknown products were also found. NDMA was reduced to 1,1-dimethylhydrazine (unsymmetrical dimethylhydrazine, UDMH). Then, UDMH was reduced into dimethylamine (DMA) by the Fe/Cu(II) and Zn/Cu(II) systems. Catalytic hydrogenation was proposed as the reduction mechanism. Several copper species, such as Cu(OH)2 in the Fe/Cu(II) system and Cu2O and Cu(OH)2 in the Zn/Cu(II) system enhanced NDMA reduction. Differences between the Fe/Cu(II) and Zn/Cu(II) systems were caused by the reduction potentials and surface conditions of the different metals and the copper species in the various systems.

  8. Synthesis, Structure, and Reactivity of Co(II) and Ni(II) PCP Pincer Borohydride Complexes

    PubMed Central

    2015-01-01

    The 15e square-planar complexes [Co(PCPMe-iPr)Cl] (2a) and [Co(PCP-tBu)Cl] (2b), respectively, react readily with NaBH4 to afford complexes [Co(PCPMe-iPr)(η2-BH4)] (4a) and [Co(PCP-tBu)(η2-BH4)] (4b) in high yields, as confirmed by IR spectroscopy, X-ray crystallography, and elemental analysis. The borohydride ligand is symmetrically bound to the cobalt center in η2-fashion. These compounds are paramagnetic with effective magnetic moments of 2.0(1) and 2.1(1) μB consistent with a d7 low-spin system corresponding to one unpaired electron. None of these complexes reacted with CO2 to give formate complexes. For structural and reactivity comparisons, we prepared the analogous Ni(II) borohydride complex [Ni(PCPMe-iPr)(η2-BH4)] (5) via two different synthetic routes. One utilizes [Ni(PCPMe-iPr)Cl] (3) and NaBH4, the second one makes use of the hydride complex [Ni(PCPMe-iPr)H] (6) and BH3·THF. In both cases, 5 is obtained in high yields. In contrast to 4a and 4b, the borohydride ligand is asymmetrically bound to the nickel center but still in an η2-mode. [Ni(PCPMe-iPr)(η2-BH4)] (5) loses readily BH3 at elevated temperatures in the presence of NEt3 to form 6. Complexes 5 and 6 are both diamagnetic and were characterized by a combination of 1H, 13C{1H}, and 31P{1H} NMR, IR spectroscopy, and elemental analysis. Additionally, the structure of these compounds was established by X-ray crystallography. Complexes 5 and 6 react with CO2 to give the formate complex [Ni(PCPMe-iPr)(OC(C=O)H] (7). The extrusion of BH3 from [Co(PCPMe-iPr)(η2-BH4)] (4a) and [Ni(PCPMe-iPr)(η2-BH4)] (5) with the aid of NH3 to yield the respective hydride complexes [Co(PCPMe-iPr)H] and [Ni(PCPMe-iPr)H] (6) and BH3NH3 was investigated by DFT calculations showing that formation of the Ni hydride is thermodynamically favorable, whereas the formation of the Co(II) hydride, in agreement with the experiment, is unfavorable. The electronic structures and the bonding of the borohydride ligand in [Co

  9. Energetic changes in the surface of activated carbons and relationship with Ni(II) adsorption from aqueous solution

    NASA Astrophysics Data System (ADS)

    Rodríguez-Estupiñan, Paola; Giraldo, Liliana; Moreno-Piraján, Juan Carlos

    2013-12-01

    This study investigated Ni(II) ion adsorption from aqueous solution on activated carbons obtained by chemically modifying the surface with the oxidizing agents nitric acid and hydrogen peroxide (CAGoxP and CAGoxN, respectively). The activated carbons were characterized by total acidity and basicity, pH at the point of charge zero determination and IR spectroscopy. Textural parameters such as the BET area and pore volumes were evaluated by gas adsorption. The BET area of the materials was between 816 and 876 m2 g-1. Additionally, the immersion enthalpies of the activated carbons in water and benzene were determined. The experimental results on adsorption in solution were adjusted to the Langmuir and Freundlich models, obtaining values for the monolayer capacity between 29.68 and 50.97 mg g-1, which indicates that the adsorption capacity depends largely on solid surface chemistry.

  10. DNA interaction with octahedral and square planar Ni(II) complexes of aspartic-acid Schiff-bases

    NASA Astrophysics Data System (ADS)

    Sallam, S. A.; Orabi, A. S.; Abbas, A. M.

    2011-12-01

    Ni(II) complexes of (S,E)-2-(2-OHbenzilydene)aspartic acid; (S,E)-2-(2,3-diOHbenzilydene)aspartic acid-; (S,E)-2-(2,4-diOH-benzilydene)aspartic acid; (S,E)-2-(2,5-diOHbenzilydene)aspartic acid and (S,E)-2-((2-OHnaphthalene-1-yl)methylene)aspartic acid Schiff-bases have been synthesized by template method in ethanol or ammonia media. They were characterized by elemental analyses, conductivity measurements, magnetic moment, UV, IR and 1H nmr spectra as well as thermal analysis (TG, DTG, DTA). The Schiff-bases are dibasic tridentate or tetradentate donors and the complexes have square planar and octahedral structures. The complexes decompose in two or three steps where kinetic and thermodynamic parameters of the decomposition steps were computed. The interactions of the formed complexes with FM-DNA were monitored by UV and fluorescence spectroscopy.

  11. Decontamination of solutions containing Cu(II) and ligands tartrate, glycine and quadrol using metallic iron.

    PubMed

    Gyliene, Ona; Vengris, Tomas; Nivinskiene, Ona; Binkiene, Rima

    2010-03-15

    Decontamination of solutions containing Cu(II) complexes with tartrate, glycine and quadrol (N,N,N'N'-tetrakis(2-hydroxypropyl)ethylenediamine) using metallic iron depends on pH and proceeds best in mildly acidic solutions. Cu(II) is completely removed from all solutions containing the ligands investigated. The degree of ligand removal from solutions considerably differs. Tartrate is relatively rapidly and completely removed from solutions. A complete removal of glycine is prolonged. The removal of quadrol from solutions using metallic iron is negligible. Electrochemical investigations showed that tartrate and glycine have inhibitory influence on anodic dissolution of iron at pH 2 and enhance it at pH 4. Quadrol does not exhibit any significant influence on iron dissolution. Chemical analysis and FT-IR investigations have shown that the content of organic compounds is the greatest in the precipitate formed in solutions containing tartrate, while it is considerably lower in glycine containing solutions. The precipitate formed in quadrol-containing solutions during the treatment with metallic iron contains only negligible amount of organics.

  12. Spectroscopic and Electronic Structure Studies of Phenolate Cu(II) Complexes

    PubMed Central

    Ghosh, Somdatta; Cirera, Jordi; Vance, Michael A.; Ono, Tetsuya; Fujisawa, Kiyoshi; Solomon, Edward I.

    2009-01-01

    A combination of spectroscopies and DFT calculations have been used to define the electronic structures of two crystallographically defined CuII-phenolate complexes. These complexes differ in the orientation of the phenolate ring which results in different bonding interactions of the phenolate donor orbitals with the CuII, which are reflected in the very different spectroscopic properties of the two complexes. These differences in electronic structures lead to significant differences in DFT calculated reactivities with oxygen. These calculations suggest that oxygen activation via a CuI phenoxyl ligand-to-metal charge transfer (LMCT) complex is highly endergonic (> 50 kcal/mol), hence an unlikely pathway. Rather, the two electron oxidation of the phenolate forming a bridging CuII peroxoquinone complex is more favorable (11.3 kcal/mol). The role of the oxidized metal in mediating this two electron oxidation of the coordinated phenolate and its relevance to the biogenesis of the covalently bound topa quinone in amine oxidase are discussed. PMID:18998639

  13. Cu(II) coordination structure determinants of the fibrillization switch in Abeta peptides

    NASA Astrophysics Data System (ADS)

    Hernandez-Guzman, Jessica; Sun, Li; Mehta, Anil; Lynn, David; Warncke, Kurt

    2010-03-01

    Alzheimer's Disease (AD) is associated with the aggregation and fibrillization of the beta-amyloid protein (Abeta). The coordination of Cu(II) by peptide histidine imidazole sidechains is proposed to play an important role in determining the fibrillization ``switch'' [1]. We have developed techniques of powder X-band electron spin echo envelope modulation (ESEEM) spectroscopy to determine the 3D molecular structure of the Cu(II)-histidine imidazole coordination in cryotrapped soluble and fibrillar forms of Abeta peptides, in order to gain insight into the factors that govern fibrillization. We use hybrid optimization-based OPTESIM [2] simulation of the double quantum harmonic feature to determine the mutual orientation of the imidazole rings in Cu(II)--bis-imidazole complexes and in Abeta(13-21) peptides. The Cu(II) coordination mode and assembly constraints in fibrils are revealed. [1] Dong , J., et al., Proc. Natl. Acad. Sci., 2007, 104, 13313. [2] Sun, L., et al., J. Magn. Reson. 2009, 200, 21.

  14. Crystal polymorphism of (μ4-O)-body centered adamantanoid Cu(II) complexes

    NASA Astrophysics Data System (ADS)

    Olijnyk, V.; Zarychta, B.

    2016-02-01

    Two novel polymorphs of [Cu4(μ4-O)(μ-Cl)6(DASO)4], (DASO = diallyl sulfoxide; C6H10OS), rhombic (C) and triclinic (D), were obtained and examined by single crystal X-ray diffraction analysis at two temperatures, 295(2) and 100(1) K. This study, in addition to our recent work on the tetragonal (A) and trigonal (B) forms of the title compound, allowed determining the nature of polymorphism and temperature-induced phase transitions. It is stated that both the packing arrangement and the displacive transformation integrate these structures, forming the symmetrically and thermodynamically related series: A,B → C → D. The C3h → C4 distortion of Cu(II) trigonal bipyramidal coordination geometry underlies the static disorder of adamantanoid cage, resulting in the thermal order-disorder phase transition. The square-pyramidal distortion degree as well as the disorder rate may be crucial for anomalous magnetic behaviour of (μ4-O)-body centered adamantanoid Cu(II) complexes.

  15. Recovery of Cu(II) by chemical reduction using sodium dithionite.

    PubMed

    Chou, Yi-Hsuan; Yu, Jui-Hsuan; Liang, Yang-Min; Wang, Pin-Jan; Li, Chi-Wang; Chen, Shiao-Shing

    2015-12-01

    Wastewaters containing Cu(II) along with ligands are ubiquitous in various industrial sectors. Efficacy of treatment processes for copper removal, especially precipitation, is greatly debilitated by ligands. Chemical reduction being commonly employed for production of metal nanoparticles has also been used for removing copper. Addition of ammonia was reported to be essential for improving copper reduction efficiency by increasing copper solubility at alkaline pH values. In this study, chemical reduction was employed to treat ligand-containing wastewater, exploiting the fact that ligands and metals are coexisted in many wastewaters. Result shows that copper ions were removed by either reduction or precipitation mechanisms depending on pH, type of ligands, and mixing condition. Complete copper reduction/removal was achieved under optimal condition. The lowest removal efficiency observed at pH 9.0 for ammonia system is due to formation of nano-sized particles, which are readily to pass through 0.45μm filter used for sample pretreatment before copper analysis. Instead of producing metallic copper, cuprous and copper oxide are identified in the samples collected from ammonia system and EDTA system, respectively. Re-oxidation of metallic copper particles by atmospheric oxygen during sample handling or incomplete reduction of Cu(II) ions during reduction process might be the cause. Finally, reduction process was applied to treat real wastewater, achieving complete removal of copper but only 10% of nickel.

  16. Visual sensor for the detection of trace Cu(II) ions using an immunochromatographic strip.

    PubMed

    Xing, Changrui; Feng, Min; Hao, Changlong; Xu, Liguang; Wang, Libing; Xu, Chuanlai

    2013-01-01

    A rapid and simple immunochromatography method based on a gold nanoparticle-labeled monoclonal antibody was developed for the on-site detection of copper (Cu) in water samples. This monoclonal antibody, obtained by a cell fusion technique, recognized the Cu-ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) complex, but not metal-free EDTA, with high sensitivity and specificity. In optimized conditions, the visual limit of detection for qualitative detection of Cu(II) ions was 10 ng/mL and the LOD for semi-quantitative detection decreased to 0.45 ng/mL with the help of a scanning reader system. The detection process was achieved within 10 min with no cross-reactivity from other heavy metal ions. The recovery of the test samples ranged from 98% to 109%. To our knowledge, this antibody-based test strip for Cu(II) ions has not been previously reported. Based on the above results, this strip sensor could be used as an alternative tool for screening heavy metal pollution in the environment.

  17. The Design and Implementation of Adsorptive Removal of Cu(II) from Leachate Using ANFIS

    PubMed Central

    Turan, Nurdan Gamze; Ozgonenel, Okan

    2013-01-01

    Clinoptilolite was investigated for the removal of Cu(II) ions from industrial leachate. Adaptive neural fuzzy interface system (ANFIS) was used for modeling the batch experimental system and predicting the optimal input values, that is, initial pH, adsorbent dosage, and contact time. Experiments were studied under laboratory batch and fixed bed conditions. The outcomes of suggested ANFIS modeling were then compared to a full factorial experimental design (23), which was utilized to assess the effect of three factors on the adsorption of Cu(II) ions in aqueous leachate of industrial waste. It was observed that the optimized parameters are almost close to each other. The highest removal efficiency was found as about 93.65% at pH 6, adsorbent dosage 11.4 g/L, and contact time 33 min for batch conditions of 23 experimental design and about 90.43% at pH 5, adsorbent dosage 15 g/L and contact time 35 min for batch conditions of ANFIS. The results show that clinoptilolite is an efficient sorbent and ANFIS, which is easy to implement and is able to model the batch experimental system. PMID:23844405

  18. Batch and dynamic sorption of Ni(II) ions by activated carbon based on a native lignocellulosic precursor.

    PubMed

    Nabarlatz, Debora; de Celis, Jorge; Bonelli, Pablo; Cukierman, Ana Lea

    2012-04-30

    Vinal-derived Activated Carbon (VAC) developed by phosphoric acid activation of sawdust from Prosopis ruscifolia native wood was tested for the adsorption of Ni(II) ions from dilute solutions in both batch and dynamic modes, comparing it with a Commercial Activated Carbon (CAC). Batch experiments were performed to determine adsorption kinetics and equilibrium isotherms for both carbons. It was possible to remove near 6.55 mg Ni g(-1) VAC and 7.65 mg Ni g(-1) CAC after 5 h and 10 h contact time, respectively. A pseudo second order equation fitted well with the kinetics of the process, and Langmuir adsorption model was used to adjust the experimental results concerning the adsorption isotherm. The parameters obtained indicate a stronger interaction between sorbent and sorbate for VAC (K = 26.56 L mmol(-1)) than for CAC (K = 19.54 L mmol(-1)). Continuous experiments were performed in a fixed-bed column packed with the investigated carbons, evaluating the influence of operational parameters such as flow rate, bed height and feed concentration on the breakthrough curves obtained. The breakthrough occurred more slowly for low concentrations of the metal ion in the feed, low flow rates and high bed height. The breakthrough curves were properly represented by Hall's model for both carbon types. Regeneration of the vinal activated carbon in column was tested, obtaining the same breakthrough curve in a new cycle of use. Finally, vinal-derived activated carbon can effectively be used to treat wastewater having until 30 ppm Ni(II).

  19. Calix receptor edifice; scrupulous turn off fluorescent sensor for Fe(III), Co(II) and Cu(II).

    PubMed

    Bhatt, Keyur D; Gupte, Hrishikesh S; Makwana, Bharat A; Vyas, Disha J; Maity, Debdeep; Jain, Vinod K

    2012-11-01

    Novel Supramolecular fluorescence receptor derived from calix-system i.e. calix[4]resorcinarene bearing dansylchloride as fluorophore was designed and synthesized. The compound was purified by column chromatography and characterized by elemental analysis, NMR and Mass spectroscopy. Tetradansylated calix[4] resorcinarene (TDCR) shows a boat conformation with C(2)v symmetry. The complexation behaviour of metal cations [Ag(I), Cd(II), Co(II), Fe(III), Hg(II), Cu(II), Pb(II), Zn(II), U(VI) (1 × 10(-4) M)] with tetra dansylated calix[4]resorcinarene (1 × 10(-6) M) was studied by spectophotometry and spectrofluorometry. Red shift in the absorption spectra led us to conclude that there is strong complexation Fe(III), Co(II) and Cu(II) with TDCR. These metal cations also produce quenching with red shifts in the emission spectra. The maximum quenching in emission intensity was observed in the case of Fe(III) and its binding constant was also found to be significantly higher than that of Co(II) and Cu(II). Quantum yield of metal complexes of Fe(III) was found to be lower in comparison with Co(II) and Cu(II) complexes. Stern Volmer analysis indicates that the mechanism of fluorescence quenching is either purely dynamic, or purely static.

  20. Lifetime response of contemporary versus resurrected Daphnia galeata Sars (Crustacea, Cladocera) to Cu(II) chronic exposure.

    PubMed

    Piscia, Roberta; Colombini, Maria; Ponti, Benedetta; Bettinetti, Roberta; Monticelli, Damiano; Rossi, Valeria; Manca, Marina

    2015-01-01

    Resurrecting legacy lineages of organisms from sediment cores of known geological age allows us to understand how environmental change can cause selection pressures that constrain the variation of populations over time. We quantified the lifetime tolerance and effects of Cu(II) exposure on Daphnia galeata in a polluted subalpine lake by comparing extant individuals with those resurrected from ephippia extracted from ca. 30-years-old sediments. Laboratory experiments were conducted using two Cu(II) concentrations, 40 and 10 µg L(-1), corresponding to the levels recorded in the lake, during chemical recovery, when Daphnia first re-appeared and succeeded. Contemporary Daphnia were unable to survive after the 10th day at either of the Cu(II) concentrations, and were unable to successfully reproduce. Daphnia cohorts from the past performed better in low Cu(II) concentrations than in copper-free, control conditions. The copper-adapted, tolerant Daphnia strains grew faster under non-toxic conditions, but were unable to survive new pollution events.

  1. EPR interpretation, magnetism and biological study of a Cu(II) dinuclear complex assisted by a schiff base precursor.

    PubMed

    Das, Kuheli; Patra, Chiranjit; Sen, Chandana; Datta, Amitabha; Massera, Chiara; Garribba, Eugenio; El Fallah, Mohamed Salah; Beyene, Belete B; Hung, Chen-Hsiung; Sinha, Chittaranjan; Askun, Tulin; Celikboyun, Pinar; Escudero, Daniel; Frontera, Antonio

    2016-12-30

    A new Cu(II) dinuclear complex, Cu2L2 (1) was afforded employing the potentially pentatentate Schiff base precursor H2L, a refluxed product of o-vanillin and diethylenetriamine in methanol. Complex 1 was systematically characterized by FTIR, UV-Vis, emission and EPR spectrometry. The single crystal X-ray diffraction analysis of 1 reveals that the copper atom exhibits a distorted square planar geometry, comprising two pairs of phenolato-O and imine-N donors from two different H2L ligands. The temperature dependent magnetic interpretation agrees with the existence of weak antiferromagnetic interactions between the bridging dinuclear Cu(II) ions. A considerable body of experimental evidence has been accumulated to elucidate the magneto-structural relationship in this dinuclear Cu(II) complex by DFT computation. Both the ligand and complex 1 exhibit anti-mycobacterial activity and considerable efficacy on M. tuberculosis H37Ra (ATCC 25177) and M. tuberculosis H37Rv (ATCC 25618) strains. The practical applicability of the ligand and complex 1 has been examined in living cells (African Monkey Vero Cells). The MTT assay proves the non-toxicity of the probe up to 100 mg mL(-1). A new homometallic dinuclear Cu(II) complex is afforded with a tetradentate Schiff base precursor. EPR interpretation and temperature dependent magnetic studies show that complex 1 has weak antiferromagnetic coupling and DFT computation is governed to explain the magneto-structural correlation.

  2. Removal and separation of Cu(II) from aqueous solutions using nano-silver chitosan/polyacrylamide membranes.

    PubMed

    Abou El-Reash, Y G; Abdelghany, A M; Elrazak, A Abd

    2016-05-01

    In the present study, adsorption of Cu(II) ions from aqueous solutions was evaluated using new thin adsorptive membranes modified with silver nanoparticles. Membranes were prepared from chitosan/polyacrylamide polymer blend. The variation of adsorption process was investigated in batch sorption mode. Infrared absorption spectra were applied for chemical characterization of the prepared polymer blend. Thermogravimetric analysis showed that addition of polyacrylamide to chitosan increased its thermal stability. The kinetics and thermodynamic parameters of Cu(II) ions adsorption onto the membranes were studied by removal experiments of Cu(II) ions from standard aqueous solutions. The kinetic data fitted to the traditional Lagergren adsorption kinetic equations. Thermodynamic studies indicated endothermic (ΔH°> 0) and spontaneous (ΔG°< 0) adsorption together with entropy generation (ΔS°> 0) at the solid/liquid interface process. Regeneration experiments showed that the newly prepared membranes could be reconditioned without significant loss of its initial properties even after three adsorption-desorption cycles. The results suggest that the prepared composite membranes can be efficiently applied for the adsorptive removal of Cu(II) ions from natural water samples. Antimicrobial activity was tested against two gram negatives, two gram positives and Candida sp. microbes and they showed a remarkable bioactivity indicating the capability of applying such membranes for a dual action.

  3. Sorption of Cu(II) Ions on Chitosan-Zeolite X Composites: Impact of Gelling and Drying Conditions.

    PubMed

    Djelad, Amal; Morsli, Amine; Robitzer, Mike; Bengueddach, Abdelkader; di Renzo, Francesco; Quignard, Françoise

    2016-01-19

    Chitosan-zeolite Na-X composite beads with open porosity and different zeolite contents were prepared by an encapsulation method. Preparation conditions had to be optimised in order to stabilize the zeolite network during the polysaccharide gelling process. Composites and pure reference components were characterized using X-ray diffraction (XRD); scanning electron microscopy (SEM); N₂ adsorption-desorption; and thermogravimetric analysis (TG). Cu(II) sorption was investigated at pH 6. The choice of drying method used for the storage of the adsorbent severely affects the textural properties of the composite and the copper sorption effectiveness. The copper sorption capacity of chitosan hydrogel is about 190 mg·g(-1). More than 70% of this capacity is retained when the polysaccharide is stored as an aerogel after supercrititcal CO₂ drying, but nearly 90% of the capacity is lost after evaporative drying to a xerogel. Textural data and Cu(II) sorption data indicate that the properties of the zeolite-polysaccharide composites are not just the sum of the properties of the individual components. Whereas a chitosan coating impairs the accessibility of the microporosity of the zeolite; the presence of the zeolite improves the stability of the dispersion of chitosan upon supercritical drying and increases the affinity of the composites for Cu(II) cations. Chitosan-zeolite aerogels present Cu(II) sorption properties.

  4. Circular serendipity: in situ ligand transformation for the self-assembly of an hexadecametallic [Cu(II)16] wheel.

    PubMed

    Kostopoulos, Andreas K; Katsenis, Athanassios D; Frost, Jamie M; Kessler, Vadim G; Brechin, Euan K; Papaefstathiou, Giannis S

    2014-12-11

    A [Cu(II)16] wheel was isolated serendipitously from the reaction of acetylacetone dioxime with copper(ii) chloride and lanthanide ions in a reaction initially designed to produce heterometallic 3d-4f cages. The ligand has been transformed in situ to three different forms, all found within the [Cu16] wheel, with the original ligand completely absent.

  5. Synthesis, structural characterization, fluorescence, antimicrobial, antioxidant and DNA cleavage studies of Cu(II) complexes of formyl chromone Schiff bases.

    PubMed

    Kavitha, P; Saritha, M; Laxma Reddy, K

    2013-02-01

    Cu(II) complexes have been synthesized from different Schiff bases, such as 3-((2-hydroxy phenylimino)methyl)-4H-chromen-4-one (HL(1)), 2-((4-oxo-4H-chromen-3-yl)methylneamino) benzoicacid (HL(2)), 3-((3-hydroxypyridin-2-ylimino)methyl)-4H-chromen-4-one (HL(3)) and 3-((2-mercaptophenylimino)methyl)-4H-chromen-4-one (HL(4)). The complexes were characterized by analytical, molar conductance, IR, electronic, magnetic, ESR, thermal, powder XRD and SEM studies. The analytical data reveal that metal to ligand molar ratio is 1:2 in all the complexes. Molar conductivity data indicates that all the Cu(II) complexes are neutral. On the basis of magnetic and electronic spectral data, distorted octahedral geometry is proposed for all the Cu(II) complexes. Thermal behaviour of the synthesized complexes illustrates the presence of lattice water molecules in the complexes. X-ray diffraction studies reveal that all the ligands and their Cu(II) complexes have triclinic system with different unit cell parameters. Antimicrobial, antioxidant and DNA cleavage activities indicate that metal complexes exhibited greater activity as compared with ligands.

  6. Numerical Simulations Reveal Randomness of Cu(II) Induced Aβ Peptide Dimerization under Conditions Present in Glutamatergic Synapses

    PubMed Central

    Goch, Wojciech; Bal, Wojciech

    2017-01-01

    The interactions between the Aβ1–40 molecules species and the copper ions (Cu(II)) were intensively investigated due to their potential role in the development of the Alzheimer Disease (AD). The rate and the mechanism of the Cu(II)—Aβ complexes formation determines the aggregation pathway of the Aβ species, starting from smaller but more cytotoxic oligomers and ending up in large Aβ plaques, being the main hallmark of the AD. In our study we exploit the existing knowledge on the Cu(II)—Aβ interactions and create the theoretical model of the initial phase of the copper- driven Aβ aggregation mechanism. The model is based on the direct solution of the Chemical Master Equations, which capture the inherent stochastics of the considered system. In our work we argue that due to a strong Cu(II) affinity to Aβ and temporal accessibility of the Cu(II) ions during normal synaptic activity the aggregation driven by Cu(II) dominates the pure Aβ aggregation. We also demonstrate the dependence of the formation of different Cu(II)—Aβ complexes on the concentrations of reagents and the synaptic activity. Our findings correspond to recent experimental results and give a sound hypothesis on the AD development mechanisms. PMID:28125716

  7. Surface adsorption and self-assembly of Cu(II) ions on TEMPO-oxidized cellulose nanofibers in aqueous media.

    PubMed

    Liu, Peng; Oksman, Kristiina; Mathew, Aji P

    2016-02-15

    TEMPO-mediated oxidized cellulose nanofibers (TOCNFs) have shown potential in the bioremediation of metal ions from contaminated water due to their interaction with positively charged metal ions via electrostatic interactions involving surface carboxyl groups. Copper is one of the most common pollutants in industrial effluents and is thus the target metal in the current study. The specific surface adsorption of Cu(II) was similar for TOCNFs with different degrees of functionalization and directly impacted the zeta potential. SEM imaging of the TOCNF after Cu(II) adsorption revealed interesting nanostructured clusters that were attributable to Cu(II) ions first being adsorbed by carboxylate groups on the TOCNF and subsequently being reduced and self-assembled to Cu(0) nanoparticles (NPs) or copper oxide NPs by microprecipitation. TOCNF turned superhydrophilic and resulted in faster water filtration after copper adsorption due to the stronger polarity of the copper ions or the self-assembled Cu(0) NPs creating voids or highly water-permeable channels at the interface between the interconnected TEMPO-oxidized nanofibers. Thus, the adsorption of Cu(II) ions and self-assembly into the Cu NPs on TOCNF favors a faster water purification process and provides a viable route to reuse/recycle TOCNFs studded with Cu nanoparticles as biocidal materials.

  8. The coupling of carbon dioxide and epoxides by phenanthroline derivatives containing different Cu(II) complexes as catalyst.

    PubMed

    Kilic, Ahmet; Palali, Ahmet Arif; Durgun, Mustafa; Tasci, Zeynep; Ulusoy, Mahmut

    2013-09-01

    A series of the mononuclear Cu(II) metal complexes containing the ligand Bdppz [(9a,13a-dihydro-4,5,9,14-tetraaza-benzo[b]triphenylene-11-yl)-phenyl-methanone] (L1) and Aqphen [(12,17-dihydronaphthol[2,3-h]dipyrido[3,2-a:2',3'-c]-phenazine-12,17-dione)] (L2) were synthesized and used as catalyst for the coupling of carbon dioxide (CO2) and liquid epoxide which served as both reactant and solvent. Dimethylamino pyridine (DMAP) was used as co-catalyst. The yields of epoxides to corresponding cyclic carbonates were determined by comparing the ratio of product to substrate in the (1)H NMR spectrum of an aliquot of the reaction mixture. The mononuclear Cu(II) complexes of these ligands were synthesized by treating an ethanol solvent of the appropriate ligand with a different molar amount of CuCl2·2H2O. The Cu(II) complexes were characterized by FT-IR, UV-Vis, elemental analysis, melting point analysis, mass spectra, molar conductivity measurements and magnetic susceptibility techniques. The reaction of the Bdppz and Aqphen ligands in a 1:1, 1:2 or 1:3 mole ratio with CuCl2·2H2O afforded ionic Cu(II) complexes in the presence of Et3N.

  9. Correlation between circuital current, Cu(II) reduction and cellular electron transfer in EAB isolated from Cu(II)-reduced biocathodes of microbial fuel cells.

    PubMed

    Shen, Jingya; Huang, Liping; Zhou, Peng; Quan, Xie; Puma, Gianluca Li

    2017-04-01

    The performance of four indigenous electrochemically active bacteria (EAB) (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) was evaluated for Cu(II) reduction on the cathodes of microbial fuel cells (MFCs). These EAB were isolated from well adapted mixed cultures on the MFC cathodes operated for Cu(II) reduction. The relationship between circuital current, Cu(II) reduction rate, and cellular electron transfer processes was investigated from a mechanistic point of view using X-ray photoelectron spectroscopy, scanning electronic microscopy coupled with energy dispersive X-ray spectrometry, linear sweep voltammetry and cyclic voltammetry. JY1 and JY5 exhibited a weak correlation between circuital current and Cu(II) reduction. A much stronger correlation was observed for JY3 followed by JY6, demonstrating the relationship between circuital current and Cu(II) reduction for these species. In the presence of electron transfer inhibitors (2,4-dinitrophenol or rotenone), significant inhibition on JY6 activity and a weak effect on JY1, JY3 and JY5 was observed, confirming a strong correlation between cellular electron transfer processes and either Cu(II) reduction or circuital current. This study provides evidence of the diverse functions played by these EAB, and adds to a deeper understanding of the capabilities exerted by diverse EAB associated with Cu(II) reduction.

  10. 3D-RISM-MP2 Approach to Hydration Structure of Pt(II) and Pd(II) Complexes: Unusual H-Ahead Mode vs Usual O-Ahead One.

    PubMed

    Aono, Shinji; Mori, Toshifumi; Sakaki, Shigeyoshi

    2016-03-08

    Solvation of transition metal complexes with water has been one of the fundamental topics in physical and coordination chemistry. In particular, Pt(II) complexes have recently attracted considerable interest for their relation to anticancer activity in cisplatin and its analogues, yet the interaction of the water molecule and the metal center has been obscured. The challenge from a theoretical perspective remains that both the microscopic solvation effect and the dynamical electron correlation (DEC) effect have to be treated simultaneously in a reasonable manner. In this work we derive the analytical gradient for the three-dimensional reference interaction site model Møller-Plesset second order (3D-RISM-MP2) free energy. On the basis of the three-regions 3D-RISM self-consistent field (SCF) method recently proposed by us, we apply a new layer of the Z-vector method to the CP-RISM equation as well as point-charge approximation to the derivatives with respect to the density matrix elements in the RISM-CPHF equation to remarkably reduce the computational cost. This method is applied to study the interaction of H2O with the d(8) square planar transition metal complexes in aqueous solution, trans-[Pt(II)Cl2(NH3)(glycine)] (1a), [Pt(II)(NH3)4](2+) (1b), [Pt(II)(CN)4](2-) (1c), and their Pd(II) analogues 2a, 2b, and 2c, respectively, to elucidate whether the usual H2O interaction through O atom (O-ahead mode) or unusual one through H atom (H-ahead mode) is stable in these complexes. We find that the interaction energy of the coordinating water and the transition metal complex changes little when switching from gas to aqueous phase, but the solvation free energy differs remarkably between the two interaction modes, thereby affecting the relative stability of the H-ahead and O-ahead modes. Particularly, in contrast to the expectation that the O-ahead mode is preferred due to the presence of positive charges in 1b, the H-ahead mode is also found to be more stable. The O

  11. Co-sorption of ofloxacin and Cu(II) in soils before and after organic matter removal.

    PubMed

    Wu, Di; Li, Hao; Liao, Shaohua; Sun, Xiaolong; Peng, Hongbo; Zhang, Di; Pan, Bo

    2014-05-15

    Various mechanisms play roles simultaneously for antibiotic sorption on solid particles. Previous studies simply emphasized mechanisms that match the increased or decreased antibiotic sorption by metal ions, without a general concept including these diverse mechanisms in their co-sorption. We observed both increased and decreased OFL and Cu(II) sorption in their co-sorption system. The comparison of the sorption coefficients of primary adsorbate (Kd(pri)) and co-adsorbate (Kd(co)) suggested that enhanced sorption occurred at high Kd(pri) region (low primary adsorbate concentration). Competitive sorption was observed when Kd(pri) was decreased to a certain value depending on solid particle properties. We thus summarized that if the adsorbates were introduced with low concentrations, OFL (such as hydrophobic region in solid particles) and Cu(II) (such as inner-sphere complexation sites) occupied their unique high-energy sorption sites. Cu(II) complexed with the adsorbed OFL, and OFL bridged by the adsorbed Cu(II) promoted the sorption for both chemicals. With the increased concentrations, the adsorbates spread to some common sorption sites with low sorption energy, such as cation exchange and electrostatic attraction region. The overlapping of Cu(II) and OFL on these sorption sites resulted in competitive sorption at high concentrations. The previously reported apparently increased or decreased sorption in antibiotic-metal ion co-sorption system may be only a part of the whole picture. Extended study on the turning point of decreased and increased sorption relating to water chemistry conditions and solid particle properties will provide more useful information to predict antibiotic-metal ion co-sorption.

  12. Interaction of the water soluble fraction of MSW-composts with Pb(II) and Cu(II) ions.

    PubMed

    Castaldi, Paola; Demurtas, Daniela; Silvetti, Margherita; Deiana, Salvatore; Garau, Giovanni

    2017-05-01

    In this study we report on the interactions between the water-soluble fraction (WSF) of two municipal solid waste composts (C1- and C2-WSF) with Pb(II) and Cu(II) ions at pH 4.5. The Me(II) addition to the compost-WSFs led to the formation of soluble Me(II)-organic complexes (as highlighted by FT-IR spectroscopy), and to a decrease of the trace metals' solubility, which was greater for Pb(II) than Cu(II). This was due to the formation of insoluble Me(II) complexes involving the water-soluble organic carbon (WSOC) and the inorganic anions within both WSFs [1.10 and 0.62 mmol L(-1) and 2.06 and 0.42 mmol L(-1) of Pb(II) and Cu(II) precipitated from C1- and C2-WSF respectively, when 6.4 mmol L(-1) Me(II) was added]. A loss of WSOC from both WSFs, i.e. ∼13% and <5%, was detected in the systems containing 6.4 mmol L(-1) Pb(II) and Cu(II) respectively. A significant contribution in the formation of Pb(II) precipitates was also due to phosphate, chloride and sulphate anions, since their concentrations in the WSF decreased of 80, 25 and 90%, respectively, after the addition of 6.4 mmol L(-1) Pb(II). A decrease of phosphate anions in both WSFs (∼30%) was found in the systems containing Cu(II).

  13. In situ immobilization of Cu(II) in soils using a new class of iron phosphate nanoparticles.

    PubMed

    Liu, Ruiqiang; Zhao, Dongye

    2007-08-01

    This study tested the feasibility of using a new class of iron phosphate (vivianite) nanoparticles synthesized using sodium carboxymethyl cellulose (NaCMC) as a stabilizer for in situ immobilization of Cu(II) in soils. Transmission electron microscopy measurements demonstrated that the particle size was about 8.4+/-2.9 nm. Batch tests showed that nano-sized vivianite particles can effectively reduce the leachability and in vitro bioaccessibility of Cu(II) in three representative soils (calcareous, neutral, and acidic) at the low doses of 0.61 and 3.01 mg PO(4) g(-1) soil. The Cu leachability was evaluated by the toxicity characteristic leaching procedure and in vitro bioaccessibility was evaluated by the physiological based extraction test. In the case of soil amendment with nanoparticles in 3.01 mg PO(4) g(-1) soil, Cu leachability reduced 63-87% and Cu concentrations in TCLP extract decreased from 1.74-13.33 mg l(-1) to 0.23-2.55 mg l(-1) after those soils were amended for 56 d. Meanwhile, the bioaccessibility of Cu was reduced by 54-69%. Sequential extraction procedures showed the significant decrease of water soluble/exchangeable Cu(II) and carbonate bound fractions and concomitant increase of Cu residual fraction after the soils were amended with the nanoparticles, suggesting that the formation of copper phosphate minerals through precipitation and adsorption was probably responsible for the decrease of Cu availability in soils. Visual MINTEQ modeling further revealed that Cu(3)(PO(4))(2) and Cu(5)(PO(4))(3)OH were formed in the vivianite-solid Cu(II) system, resulting in the decreased solubility of the Cu(II) in the acidic pH range.

  14. Synthesis, structure, and magnetic properties of (6-9)-nuclear Ni(II) trimethylacetates and their heterospin complexes with nitroxides.

    PubMed

    Ovcharenko, Victor; Fursova, Elena; Romanenko, Galina; Eremenko, Igor; Tretyakov, Evgeny; Ikorskii, Vladimir

    2006-07-10

    New polynuclear nickel trimethylacetates [Ni6(OH)4(C5H9O2)8(C5H10O2)4] (6), [Ni7(OH)7(C5H9O2)7(C5H10O2)6(H2O)] x 0.5 C6H14 x 0.5 H2O (7), [Ni8(OH)4(H2O)2(C5H9O2)12] (8), and [Ni9(OH)6(C5H9O2)12(C5H10O2)4] x C5H10O2 x 3 H2O (9), where C5H9O2 is trimethylacetate and C5H10O2 is trimethylacetic acid, have been found. Their structures were determined by X-ray crystallography. Because of their high solubility in low-polarity organic solvents, compounds 6-9 reacted with stable organic radicals to form the first heterospin compounds based on polynuclear Ni(II) trimethylacetate and nitronyl nitroxides containing pyrazole (L(1)-L(3)), methyl (L(4)), or imidazole (L(5)) substituent groups, respectively, in side chain [Ni7(OH)5(C5H9O2)9(C5H10O2)2(L(1))2(H2O)] x 0.5 C6H14 x H2O (6+1a), [Ni7(OH)5(C5H9O2)9(C5H10O2)2(L2)2(H2O)] x H2O (6+1b), [Ni7(OH)5(C5H9O2)9(C5H10O2)2(L(3))2(H2O)] x H2O (6+1c), [Ni6(OH)3(C5H9O2)9(C5H10O2)4(L(4))] x 1.5 C6H14 (6''), and [Ni4OH)3(C5H9O2)5(C5H10O2)4(L(5))] x 1.5 C7H8 (4). Their structures were also determined by X-ray crystallography. Although Ni(II) trimethylacetates may have varying nuclearity and can change their nuclearity during recrystallization or interactions with nitroxides, this family of compounds is easy to study because of its topological relationship. For any of these complexes, the polynuclear framework may be derived from the [Ni6] polynuclear fragment {Ni6(mu4-OH)2(mu3-OH)2(mu2-C5H9O2-O,O')6(mu2-C5H9O2-O,O)(mu4-C5H9O2-O,O,O',O')(C5H10O2)4}, which is shaped like an open book. On the basis of this fragment, the structure of 7-nuclear compounds (7 and 6+1a-c) is conveniently represented as the result of symmetric addition of other mononuclear fragments to the four Ni(II) ions lying at the vertexes of the [Ni6] open book. The 9-nuclear complex is formed by the addition of trinuclear fragments to two Ni(II) ions lying on one of the lateral edges of the [Ni6] open book. This wing of the 9-nuclear complex preserves its structure in

  15. Electronic structure aspects of the complete O2 transfer reaction between Ni(II) and Mn(II) complexes with cyclam ligands.

    PubMed

    Zapata-Rivera, Jhon; Caballol, Rosa; Calzado, Carmen J

    2015-01-28

    This work explores the electronic structure aspects involving the complete intermolecular O2 transfer between Ni(ii) and Mn(ii) complexes, both containing N-tetramethylated cyclams (TMC). The energy of the low-lying states of reactants, intermediates and products is established at the CASSCF level and also the DDCI level when possible. The orthogonal valence bond analysis of the wave functions obtained from CASSCF and DDCI calculations indicates the dominant superoxide nature of all the adducts participating in the reaction, and consequently that the whole reaction can be described as the transfer of the superoxide O2(-) between Ni(ii) and Mn(ii) complexes, without any additional change in the electronic structure of the fragments.

  16. Insolubilization of Chestnut Shell Pigment for Cu(II) Adsorption from Water.

    PubMed

    Yao, Zeng-Yu; Qi, Jian-Hua; Hu, Yong; Wang, Ying

    2016-03-28

    Chestnut shell pigment (CSP) is melanin from an agricultural waste. It has potential as an adsorbent for wastewater treatment but cannot be used in its original state because of its solubility in water. We developed a new method to convert CSP to insolubilized chestnut shell pigment (ICSP) by heating, and the Cu(II) adsorption performance of ICSP was evaluated. The conversion was characterized, and the thermal treatment caused dehydration and loss of carboxyl groups and aliphatic structures in CSP. The kinetic adsorption behavior obeyed the pseudo-second-order rate law, and the equilibrium adsorption data were well described with both the Langmuir and the Freundlich isotherms. ICSP can be used as a renewable, readily-available, easily-producible, environmentally-friendly, inexpensive and effective adsorbent to remove heavy-metal from aquatic environments.

  17. Hydrogen peroxide can be generated by tau in the presence of Cu(II).

    PubMed

    Su, Xiao-Yang; Wu, Wei-Hui; Huang, Zhi-Ping; Hu, Jia; Lei, Peng; Yu, Chun-Hui; Zhao, Yu-Fen; Li, Yan-Mei

    2007-06-29

    Alzheimer's disease has been closely related with oxidative stress, which might be responsible for the dysfunction or death of neuronal cells that contributes to disease pathogenesis. Impaired copper homeostasis makes contribution to the oxidative stress and consequently to several neurodegenerative conditions. Inappropriate binding of Cu(II) to cellular proteins are currently being explored as sources of pathological oxidative stress in several neurodegenerative disorders. Here we report that a fragment of tau protein possesses copper reduction activity and initiates the copper-mediated generation of hydrogen peroxide. The tau peptide was found to be oxidized to form disulfide bond-linked dimer. The hydrogen peroxide generated was quantified by TCEP/DTNB (tris(2-carboxyethyl) phosphine hydrochloride/5,5'-dithio-bis(2-nitrobenzoic acid). Since the copper reduction capacity and the generation of hydrogen peroxide were believe to be a major toxicological pathway of Abeta peptide, the functional similarity shared by tau and Abeta implies a new perspective of tau pathology.

  18. A spectroscopic investigation of captopril and the Cu(II) captopril system

    NASA Astrophysics Data System (ADS)

    Torreggiani, Armida; Taddei, Paola; Tosi, M. Raffaella; Tugnoli, Vitaliano

    2001-05-01

    A Raman and IR study of captopril (CpSH), a synthetic derivative of L-proline, and the Cu(II)-CpSH system at different pHs and metal/ligand ratios was carried out. The vibrational spectra suggested disulphide formation (CpSSCp) by the reduction of Cu(II) to Cu(I) and allowed the identification of the sites involved in metal coordination. Various complexes can be formed and the nature of the predominant species depends mainly on the pH. At pH 10 CpSH gives rise to two monomeric complexes with different structures depending on the metal/ligand ratio, whereas at acid pH a water-insoluble polymeric species predominates.

  19. Magnetic exchange couplings from noncollinear perturbation theory: dinuclear CuII complexes.

    PubMed

    Phillips, Jordan J; Peralta, Juan E

    2014-08-07

    To benchmark the performance of a new method based on noncollinear coupled-perturbed density functional theory [J. Chem. Phys. 138, 174115 (2013)], we calculate the magnetic exchange couplings in a series of triply bridged ferromagnetic dinuclear Cu(II) complexes that have been recently synthesized [Phys. Chem. Chem. Phys. 15, 1966 (2013)]. We find that for any basis-set the couplings from our noncollinear coupled-perturbed methodology are practically identical to those of spin-projected energy-differences when a hybrid density functional approximation is employed. This demonstrates that our methodology properly recovers a Heisenberg description for these systems, and is robust in its predictive power of magnetic couplings. Furthermore, this indicates that the failure of density functional theory to capture the subtle variation of the exchange couplings in these complexes is not simply an artifact of broken-symmetry methods, but rather a fundamental weakness of current approximate density functionals for the description of magnetic couplings.

  20. Unravelling the quenching mechanisms of a luminescent Ru(II) probe for Cu(II).

    PubMed

    Santos, André Ribeiro; Escudero, Daniel; González, Leticia; Orellana, Guillermo

    2015-03-01

    We have investigated the photophysical and photochemical features of a luminescent heteroleptic Ru(II)-polypyridyl probe and of its corresponding Ru(II)-Cu(II) dinuclear complex formed upon the analyte binding through extensive density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The molecular probe contains the tailored imidazo[4,5-f]-1,10-phenanthroline (IIP) ligand for simultaneously binding the Ru(II) core and the target metal ion in aqueous solution. We have rationalized the static photoluminescence quenching observed upon the Cu(II) coordination, on the grounds of distinct excited state deactivation mechanisms which are absent in the free Ru(II) complex probe. Additionally, the emission quenching found upon increasing the solution pH has also been investigated. When coordinated IIP deprotonates, the nature of the lowest excited state of its complex changes from (3)MLCT to (3)LLCT/(3)IL. The strong base-induced emission quenching can be understood in terms of both the energy-gap law, since the (3)LLCT/(3)IL states lie at a significantly lower energy than the (3)MLCT state increasing the contribution of non-radiative mechanisms, and the expected slower radiative rates from such (3)LLCT/(3)IL states. After Cu(II) binding, the lowest triplet excited state is similar to the analyte-free probe in both energy and electronic nature. However, Cu-centered non-radiative excited states, populated after photoinduced electron transfer and intersystem crossing processes, are responsible for the population drainage of the emissive state.

  1. π-π Stacking and ferromagnetic coupling mechanism on a binuclear Cu(II) complex.

    PubMed

    Chi, Yan-Hui; Yu, Li; Shi, Jing-Min; Zhang, Yi-Quan; Hu, Tai-Qiu; Zhang, Gui-Qiu; Shi, Wei; Cheng, Peng

    2011-02-21

    The ferromagnetic couplings were observed in an unpublished crystal that consists of binuclear copper(II) complexes, namely, [Cu(2)(μ(1,3)-SCN)(2)(PhenOH)(OCH(3))(2)(HOCH(3))(2)] (PhenOH = 2-hydroxy-1,10-phenanthroline), and in the binuclear complex Cu(ii) ion assumes a distorted octahedral geometry and thiocyanate anion functions as a μ(1,3)-SCN(-) equatorial-axial (EA) bridging ligand. The analysis for the crystal structure indicates that there are three types of magnetic coupling pathways, in which two pathways involve π-π stacking between the adjacent complexes and the third one is the μ(1,3)-SCN(-) bridged pathway. The fitting for the data of the variable-temperature magnetic susceptibilities shows that there is a ferromagnetic coupling between adjacent Cu(II) ions with J = 50.02 cm(-1). Theoretical calculations reveal that the two types of π-π stacking resulted in ferromagnetic couplings with J = 4.16 cm(-1) and J = 2.75 cm(-1), respectively, and the bridged thiocyanate anions pathway led to a weaker ferromagnetic interaction with J = 0.88 cm(-1). The theoretical calculations also indicate that the ferromagnetic coupling sign from the two types of π-π stacking does not accord with McConnell I spin-polarization mechanism. The analysis for the Wiberg bond indexes that originate from the π-π stacking atoms indicates that the Wiberg bond indexes are relevant to the associated magnetic coupling magnitude and the Wiberg bond index is one of the key factors that dominates the associated magnetic coupling magnitude.

  2. Biosorption of Cu(II) ions by cellulose of cabbage waste as biosorbent from agricultural waste

    NASA Astrophysics Data System (ADS)

    Heraldy, Eddy; Wireni, Lestari, Witri Wahyu

    2016-02-01

    Biosorption on lignocellulosic wastes has been identified as an appropriate alternative technology to remove heavy metal ions from wastewater. The purpose of this research was to study the ability of cabbage waste biosorbent prepared from agricultural waste on biosorption of Cu(II). Cabbage waste biosorbent was activated with sodium hydroxide at concentration 0.1 M. The biosorption optimum conditions were studied with initial pH (2-8), biosorbent dosage (0.2-1) g/L, contact time (15-90) minutes, and metal ion concentrations (10-100) mg/L by batch method. Experimental data were analyzed in terms of two kinetic models such as pseudo-first-order and pseudo-second-order models. Langmuir and Freundlich isotherm models were applied to describe the biosorption process. The results showed that cabbage biosorbent activated by 0.1 M sodium hydroxide enhanced the biosorption capacity from 9,801 mg/g to 12,26 mg/g. The FTIR spectra have shown a typical absorption of cellulose and typical absorption of lignin decrease after activation process. The kinetic biosorption was determined to be appropriate to the pseudo-second order model with constant rate of 0,091 g/mg.min, and the biosorption equilibrium was described well by the Langmuir isotherm model with maximum biosorption capacity of 37.04 mg/g for Cu(II) at pH 5, biosorption proses was spontaneous in nature with biosorption energy 25.86 kJ/mol at 302 K.

  3. Discrete and polymeric Cu(II) complexes featuring substituted indazole ligands: their synthesis and structural chemistry.

    PubMed

    Hawes, Chris S; Kruger, Paul E

    2014-11-21

    Reported here are the syntheses of four indazole-based ligands and the structural characterisation of four Cu(II) complexes derived from them. The ligands 1-(2-pyridyl)-1H-indazole, L1, and 2-(2-pyridyl)-2H-indazole, L2, have been characterised by single crystal X-ray diffraction methods for the first time. The intramolecular structural changes within L1 and L2 that result from the transition from the 1H to the 2H electronic configuration have been delineated. The synthesis of 1H-indazole-6-carboxylic acid, H2L3, and 1H-indazole-7-carboxylic acid, H2L4, is fully described and the structure of H2L4·H2O determined. The structures of two discrete mononuclear complexes {[Cu(L1)2(NO3)]·NO3·1.5H2O}, 1, and {[Cu(L2)2(NO3)]·NO3}, 2, have been determined and their molecular compositions corroborated by solution-based methods. Reaction of Cu(II) with H2L3 generates a 2D coordination polymer, [Cu3(HL3)4(NO3)2(EtOH)2]·3(C6H6)·2(H2O), 3, that features the archetypal [Cu2(OAc)4] paddlewheel motif and 1D channels; whereas reaction with H2L4 gives a discrete complex [Cu(HL4)2]·H2O·MeOH, 4, in which hydrogen bonding interactions link indazole dimers via a water molecule to yield a 1D network.

  4. Ni(II) and Zn(II) complexes of 2-((thiophen-2-ylmethylene)amino)benzamide: Synthesis, spectroscopic characterization, thermal, DFT and anticancer activities

    NASA Astrophysics Data System (ADS)

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B. S.

    2015-01-01

    The paper presents the synthesis of Ni(II) and Zn(II) complexes of general composition M(L)X2 and M(L)2X2 (M = Ni(II), Zn(II), X = Cl-1, OAc-1) with Schiff base obtained through the condensation of 2-aminobenzamide with thiophene-2-carbaldehyde. The characterization of newly formed complexes was done by 1H NMR, UV-VIS, TGA, IR, mass spectrophotometry and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies a distorted octahedral geometry has been assigned for Ni(II) complexes and tetrahedral geometry for Zn(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (HepG2) were studied and compared with those of free ligand.

  5. Selective and sensitized spectrophotometric determination of trace amounts of Ni(II) ion using α-benzyl dioxime in surfactant media

    NASA Astrophysics Data System (ADS)

    Ghaedi, Mehrorang

    2007-02-01

    Highly sensitive and interference-free sensitized spectrophotometric method for the determination of Ni(II) ions is described. The method is based on the reaction between Ni(II) ion and benzyl dioxime in micellar media in the presence of sodium dodecyl sulfate (SDS). The absorbance is linear from 0.1 up to 25.0 μg mL -1 in aqueous solution with repeatability (RSD) of 1.0% at a concentration of 1 μg mL -1 and a detection limit of 0.12 ng mL -1 and molar absorption coefficient of 68,600 L mol -1 cm -1. The influence of reaction variables including type and amount of surfactant, pH, and amount of ligand and complexation time and the effect of interfering ions are investigated. The proposed procedure was applied to the determination of trace amounts of Ni(II) ion in tap water, river water, chocolate and vegetable without separation or organic solvent extraction.

  6. Dual shell-like magnetic clusters containing Ni(II) and Ln(III) (Ln = La, Pr, and Nd) ions.

    PubMed

    Kong, Xiang-Jian; Ren, Yan-Ping; Long, La-Sheng; Zheng, Zhiping; Nichol, Gary; Huang, Rong-Bin; Zheng, Lan-Sun

    2008-04-07

    Dual shell-like nanoscopic magnetic clusters featuring a polynuclear nickel(II) framework encapsulating that of lanthanide ions (Ln = La, Pr, and Nd) were synthesized using Ni(NO3)(2).6H2O, Ln(NO3)(3).6H2O, and iminodiacetic acid (IDA) under hydrothermal conditions. Structurally established by crystallographic studies, these clusters are [La20Ni30(IDA)30(CO3)6(NO3)6(OH)30(H2O)12](CO3)(6).72H2O (1), [Ln20Ni21(C4H5NO4)21(OH)24(C2H2O3)6(C2O4)3(NO3)9(H2O)12](NO3)9.nH2O [C2H2O3 is the alkoxide form of glycolate; Ln = Pr (2), n = 42; Nd (3), n = 50], and {[La4Ni5Na(IDA)5(CO3)(NO3)4(OH)5(H2O)5][CO3].10H2O} infinity (4). Carbonate, oxalate, and glycolate are products of hydrothermal decomposition of IDA. Compositions of these compounds were confirmed by satisfactory elemental analyses. It has been found that the cluster structure is dependent on the identity of the lanthanide ion as well as the starting Ln/Ni/IDA ratio. The cationic cluster of 1 features a core of the Keplerate type with an outer icosidodecahedron of Ni(II) ions encaging a dodecahedral kernel of La(III). Clusters 2 and 3, distinctly different from 1, are isostructural, possessing a core of an outer shell of 21 Ni(II) ions encapsulating an inner shell of 20 Ln(III) ions. Complex 4 is a three-dimensional assembly of cluster building blocks connected by units of Na(NO3)/La(NO3)3; the structure of the building block resembles closely that of 1, with a hydrated La(III) ion internalized in the decanuclear cage being an extra feature. Magnetic studies indicated ferromagnetic interactions in 1, while overall antiferromagnetic interactions were revealed for 2 and 3. The polymeric, three-dimensional cluster network 4 displayed interesting ferrimagnetic interactions.

  7. "Self-activating" chemical nuclease: ferrocenyl cyclen Cu(II) complexes act as efficient DNA cleavage reagents in the absence of reductant.

    PubMed

    Li, Kun; Zhou, Li-Hong; Zhang, Ji; Chen, Shan-Yong; Zhang, Zhong-Wei; Zhang, Jing-Jing; Lin, Hong-Hui; Yu, Xiao-Qi

    2009-04-01

    The interactions of cyclen Cu(II) complexes functionalized by ferrocenyl group with plasmid DNA indicated that these complexes have high cleavage efficiency via an oxidative mechanism in the absence of any reductant or oxidant.

  8. Resolving ligand hyperfine couplings of type 1 and 2 Cu(II) in ascorbate oxidase by high field pulse EPR correlation spectroscopy.

    PubMed

    Potapov, Alexey; Pecht, Israel; Goldfarb, Daniella

    2010-01-07

    Ascorbate oxidase contains two paramagnetic Cu(ii) binding sites, type 1 (T1) and type 2 (T2) and in both sites the Cu(ii) is coordinated to histidine residues. We use several pulse EPR techniques at high field (95 GHz) to determine ligand (1)H and (14)N hyperfine couplings in the two sites and identify the T1 signals by a new triple resonance correlation technique named THYCOS.

  9. Octahedral Ni(II) complex with new NNO donor Schiff base ligand: Synthesis, structure and Hirshfeld surface

    NASA Astrophysics Data System (ADS)

    Jana, Kalyanmoy; Maity, Tithi; Chandra Debnath, Subhas; Samanta, Bidhan Chandra; Seth, Saikat Kumar

    2017-02-01

    A new mononuclear Schiff base octahedral Ni(II) complex of general formula [NiII(L)2] has been synthesized using a new NNO donor Schiff base ligand (HL = 2-[(piperidin-2-ylmethylimino)-methyl]-phenol). The title complex has been characterized by various physical measurements such as elemental analyses, FT-IR, 1H NMR and UV-Vis spectroscopic techniques. The molecular structure of the title complex was determined by single crystal X-ray diffraction technique. The title complex is a mononuclear bis-ligand complex showing distorted octahedral geometry around nickel (II). X-ray crystallography reveals that the complex exhibits extensive supramolecular interactions in the solid-state. Two types of non-covalent interactions namely, π-π and C-H···π interactions are found to govern final solid-state architecture in the complex. The contribution of each interaction to the formation of the self-assembly has been analyzed through Hirshfeld surface calculation which enables quantitative contributions to the crystal packing in a novel visual manner.

  10. Thermodynamic functions of Ni(II) complexes with 5-(2-hydroxyphenyl)-pyrazole derivatives. A potentiometric study

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Narwade, M. L.; Thakre, V. J.

    2013-10-01

    Proton-ligand dissociation constants of five biologically important pyrazole derivatives, viz. [5-(2-hydroxyphenyl)-3-(pyridin-3-yl)-4-benzoyl]-pyrazol (HPPBP), [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(3-pyridinoyl)]-pyrazol (HPNPPP), [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-benzoyl]-pyrazol (HPNPBP), [5-(2-hydroxyphenyl)-3-phenyl-4-(3-pyridinoyl)]-pyrazol (HPPPP), and [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(2-furoyl) pyrazol (HPNPFP) and metal ligand stability constants of their Ni(II) complexes in 70% (v/v) dioxane-water and 0.1 M KNO3 were determined at 298.15, 303.15, and 308.15 K by potentiometric method. Thermodynamic functions, such as, free energy change (Δ G ○), enthalpy change (Δ H ○) and entropy (Δ S ○) change for dissociation and complex formation have been estimated form temperature dependence of proton-ligand and metal-ligand stability constants and interpreted in terms of feasibility of these processes.

  11. Pb(II), Cu(II) and Cd(II) removal through untreated rice husk; thermodynamics and kinetics.

    PubMed

    Guiso, Maria Giovanna; Alberti, Giancarla; Emma, Giovanni; Pesavento, Maria; Biesuz, Raffaela

    2012-01-01

    The sorption properties of rice husk towards Cu(II), Cd(II) and Pb(II) were studied. The sorption isotherms are described by the Langmuir equation, and Pb(II) shows a higher affinity for rice husk compared to Cu(II) and Cd(II) under the same conditions. The kinetics of sorption obeys to a pseudo second-order equation for all metals. The sorption profiles as a function of the pH were used to characterize the stoichiometry of the sorption reaction. The competition for metal complexation by any ligand in solution is also accounted for. Upon increasing the ionic strength, the sorption curves of Pb(II) move to basic pH; this shift can be explained by considering the effect of nitrate complexes on the free metal ion concentration, since KNO(3) is used as the ionic medium. An attempt to employ rice husk in a dynamic system is presented.

  12. Cu(II) complexation by "non-coordinating" N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES buffer).

    PubMed

    Sokołowska, Magdalena; Bal, Wojciech

    2005-08-01

    The combined potentiometric and spectroscopic studies of interactions of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) with Cu(II) demonstrated that this popular buffer, commonly labelled as "non-coordinating" forms a CuL+ complex, with the logbeta(CuL) value of 3.22. This complex undergoes alkaline hydrolysis above pH 6, resulting in Cu(OH)2 precipitation. However, the presence of HEPES at a typical concentration of 100 mM at pH 7.4 elevates the apparent binding constant, being determined for a complex of another ligand, by a factor of 80. HEPES does not form ternary complexes with aminoacids Ala, Trp, and His, but may do so with other bioligands, such as nucleotides. Therefore, HEPES can still be recommended for Cu(II) studies in place of other common buffers, such as Tris and phosphate, but appropriate corrections and precautions should be applied in quantitative experiments.

  13. Development of a microalgal PAM test method for Cu(II) in waters: comparison of using spectrofluorometry.

    PubMed

    Peña-Vázquez, E; Pérez-Conde, C; Costas, E; Moreno-Bondi, M C

    2010-08-01

    Test methods are needed to monitor Cu concentrations in reservoirs and water supplies. Dictyosphaerium chlorelloides (Chlorophyta) cells were immobilized in a silicate sol-gel and the toxic effects of Cu(II) were examined using different techniques: fluorescence measurements (using a spectrofluorometer with an optic fiber coupled to a flow cell or a 96-well-plate reader) or by Pulse Amplitude Modulation (PAM) parameters using a portable instrument and the pulse saturation method. Fm' and qN were the most sensitive indicator parameters when performing Cu analysis in water. D. chlorelloides PAM biosensor presented a detection limit of 0.6 mg l(-1) for Cu(II), within the limits to establish if Cu concentrations exceeded regulatory levels. Moreover, a 1.9 mg Cu l(-1) (30 microM) resistant strain of the D. chlorelloides microalgae was produced in order to obtain more selectivity on the metal determination.

  14. X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex

    PubMed Central

    Matiadis, Dimitrios; Tsironis, Dimitrios; Stefanou, Valentina; Igglessi–Markopoulou, Olga; McKee, Vickie; Sanakis, Yiannis; Lazarou, Katerina N.

    2017-01-01

    In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed. Finally, a computational approach was performed in order to obtain a detailed and precise insight of product structures and properties. It is hoped that this study can enrich the field of functional supramolecular systems, giving place to the formation of coordination-driven self-assembly architectures. PMID:28316540

  15. Adsorption and desorption of Zn(II) and Cu(II) on Ca- alginate immobilized activated rice bran

    NASA Astrophysics Data System (ADS)

    Suratman, A.; Kamalia, N. Z.; Kusumawati, W. A.

    2016-02-01

    Ca-alginate immobilized activated rice bran has been used for adsorption of Zn(II) and Cu(II) from aqueous solution. The effect of the pH, kinetics model, adsorption isotherm and desorption on the adsorption performance was investigated. Activated rice bran was immobilized by the entrapment in alginate beads. The adsorption strength of Ca-alginate immobilized activated rice bran was compared to Ca-alginate and non-immobilized activated rice bran. The concentrations of adsorbed ions were analyzed using Atomic Absorption Spectrophotometer (AAS). The result showed that pH of 4.0 and the contact time of 120 min are the optimum condition for adsorption of Zn(II) and Cu(II). The adsorption kinetic of Zn(II) and Cu(II) followed the pseudo-second-order model with adsorption rate constant 4.9 x 10-2 and 3.14 g.mg-1.min-1, respectively. The both adsorption processes obeyed Langmuir isotherm with adsorption capacity of 2.03 and 2.42 mg.g-1 of adsorbent, respectively. The strength of Zn adsorption on Ca-alginate immobilized activated rice bran (86.63%) was more effective compared to Ca-alginate beads (60.96%) and activated rice bran (43.85%). The strength of Cu adsorption was 80.00%, 61.50% and 22.10%, respectively. The desorption of Zn(II) and Cu(II) showed that recovery percentage of the adsorption was 76.56% and 57.80% with the condition of using HCl 0.1 M as desorption agent for 1 hour.

  16. Kinetic catalytic determination of trace Cu(II) in water samples with the thioglycolic/thiolactic acid-chromate reaction.

    PubMed

    Rustoiu-Csavdari, A; Mihai, D; Bâldea, I

    2005-04-01

    The use of two novel similar indicator reactions as applied to the kinetic determination of Cu(II) in water is investigated. The methods rely on the catalytic effect of the analyte on the oxidation of thioglycolic (TGA) and thiolactic (TLA) acids by chromate in acidic media. The extent of the reactions was followed spectrophotometrically at 345 nm. Pseudo-first-order rate coefficients, k(obsd), were determined as a function of catalyst concentration. Interference of Fe(III) and Pb(II) was suppressed by complexation with pyrophosphate. For the reaction of TGA, a linear regression for k(obsd) versus [Cu(II)] was obtained for the entire concentration range considered. Although the plot corresponding to TLA oxidation exhibits a sharp change of slope at approximately 1.8x10(-5) M Cu(II), it can still be described effectively by two linear regressions with different slopes. The reaction of TGA is more sensitive than that of TLA at low Cu(II) concentration. The opposite is true for higher catalyst contents. The detection limits were 65 microg L(-1) for TGA and of 80 microg L(-1) for TLA oxidation, respectively. The relative standard deviations, of 0.4% for TGA and 1.1% for TLA oxidation, respectively, were obtained for five replicate runs at 1000 microg L(-1). Samples of river and wastewater from the mining region of Baia-Mare, Northern Romania were analyzed using the more sensitive reaction of thioglycolic acid. Results were compared to those obtained by the officially standardized methods. Good agreement was obtained, even for an untreated sample. Measurements did not require prior separation of interfering species.

  17. Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives.

    PubMed

    Zhang, Tao; Wu, Ying-Xin; Huang, Xiong-Fei; Liu, Jun-Min; Xia, Bing; Zhang, Wei-Hua; Qiu, Rong-Liang

    2012-07-01

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C(6)HEDTA (2,2'-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C(12)HEDTA (2,2'-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C(6)HEDTA and C(12)HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C(6)HEDTA or C(12)HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C(6)HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C(12)HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C(12)HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid.

  18. a Gas Phase Investigation of CuOH(H_2O)+ and Cu(II) Oligoglycine Water Oxidation Catalysts

    NASA Astrophysics Data System (ADS)

    Marsh, Brett; Zhou, Jia; Garand, Etienne

    2014-06-01

    The abundance of copper and copper compounds within the crust of the Earth and the well characterized coordination chemistry of copper species has led to investigation of copper as a catalyst for several different chemical reactions. Among the most notable of these has been the application of copper containing compounds to water oxidation. The chemistry used in this reaction has thus far been dominated by expensive materials containing the rare metals ruthenium or iridium. In this presentation we study several copper species which have attracted interest in this field including CuOH(H_2O)n+ clusters and Cu(II) oligoglycine complexes. We find that in the case of CuOH(H_2O)n+ clusters that the undercoordinated CuOH(H_2O)+ cluster has a strong affinity towards activating D2 while the higher coordinated CuOH(H_2O)2+ and CuOH(H_2O)3+ clusters show no propensity for the activation of D2. In the case of the Cu(II) oligoglycine complexes we find that the charge environment strongly affects the diagnostic CO stretch frequencies, creating a clear spectroscopic fingerprint for assessing the charge and interactions within these systems. Despite the small size (6-12 atoms) of the CuOH(H_2O)n+ clusters electronic structure methods including DFT and MP2 give poor agreement with the experimental results while DFT calculations on the relatively large Cu(II) oligoglycine species show excellent agreement with experiment.

  19. Adsorption of tetracycline on soil and sediment: effects of pH and the presence of Cu(II).

    PubMed

    Zhang, Zheyun; Sun, Ke; Gao, Bo; Zhang, Guixiang; Liu, Xitao; Zhao, Ye

    2011-06-15

    Tetracycline (TC) is frequently detected in the environment, however, knowledge on the environmental fate and transport of TC is still limited. Batch adsorption experiments of TC by soil and sediment samples were conducted. The distribution of charge and electrostatic potential of individual atoms of various TC species in the aqueous solution were determined using MOPAC version 0.034 W program in ChemBio3D Ultra software. Most of the adsorption isotherms on the soil, river and marine sediments were well fitted with the Freundlich and Polanyi-Manes (PMM) models. The single point organic carbon (OC)-normalized adsorption distribution coefficients (K(OC)) and PMM saturated adsorption capacity (Q(OC)(0)) values of TC were associated with the mesopore volume and clay content to a greater extent, indicating the mesopore volume of the soil and sediments and their clay content possibly influenced the fate and transport of TC in the natural environment. The adsorption of TC on soil and sediments strongly depended on the pH and presence of Cu(II). The presence of Cu(II) facilitated TC adsorption on soil and sediments at low pH (pH<5), possibly due to the metallic complexation and surface-bridging mechanism by Cu(II) adsorption on soil and sediments. The cation exchange interaction, metallic complexation and Coulombic interaction of mechanisms for adsorption of TC to soils and sediments were further supported by quantum chemical calculation of various TC species in different pH.

  20. Removal of Pb(II), Cd(II), Cu(II) and trichloroethylene from water by Nanofer ZVI.

    PubMed

    Eglal, Mahmoud M; Ramamurthy, Amruthur S

    2015-01-01

    Zero-valent iron nanoparticle (Nanofer ZVI) is a new reagent due to its unique structure and properties. Images of scanning electron microscopy/electron dispersive spectroscopy (SEM/EDS), transmission electron microscopy and X-ray diffraction revealed that Nanofer ZVI is stable, reactive and has a unique structure. The particles exhibited a spherical shape, a chain-like structure with a particle size of 20 to 100 nm and a surface area between 25-30 m2g(-1). The time interval for particles to agglomerate and settle was between 4-6 h. SEM/EDS Images showed that particle size increased to 2 µm due to agglomeration. Investigation of adsorption and oxidation behavior of Nanofer ZVI used for the removal of Cu(II), Pb(II), Cd(II) ions and trichloroethylene (TCE) from aqueous solutions showed that the optimal pH for Pb(II), Cu(II), Cd(II) and TCE removal were 4.5 and 4.8, 5.0 and 6.5, respectively. Test data were used to form Langmuir and Freundlich isotherms. The maximum contaminant loading was estimated as 270, 170, 110, 130 mg per gram of Nanofer ZVI for Cu(II), Pb(II), Cd(II) and TCE respectively. Removal of metal ions is interpreted in terms of their hydrated ionic radii and their electronegativity. TCE oxidation followed the dechlorination pathway resulting in nonhazardous by-products.

  1. Accelerated Sorption Diffusion for Cu(II) Retention by Anchorage of Nano-zirconium Dioxide onto Highly charged Polystyrene Material

    PubMed Central

    Zhang, Qingrui; Du, Qing; Jiao, Tifeng; Teng, Jie; Sun, Qina; Peng, Qiuming; Chen, Xinqing; Gao, Faming

    2015-01-01

    The development of nanocomposite with strong adsorption ability exhibits great potential applications for environmental remediation. However, the pore blocking in preparation frequently constrains sorption diffusion, resulting in low utilization efficiency. Here we synthesized a new nano-ZrO2/Polystyrene (NZO-PS) material tailored with a specific fixed SO3-Na group to enhance Cu(II) removal. The NZO-PS exhibits efficient Cu(II) sequestration in a wide pH range (3.0–6.5) and preferential sorption performances. The efficient kinetic behavior and column applicability suggest the blocked pore channel is not a matter when presence of negatively charged moiety, which accelerates Cu(II) sorption diffusion and enrichment toward target active site. Moreover, the exhausted NZO-PS can be readily regenerated through HCl-NaCl binary solution. The preparation route can be extended to synthesize other functional composited materials. Simultaneously, the characteristics of simplicity, high-yield and regeneration provide some promising industrial merits. PMID:26184921

  2. Spectral, thermal and biological studies of Mn(II) and Cu(II) complexes with two thiosemicarbazide derivatives.

    PubMed

    Refat, Moamen S; El-Metwaly, Nashwa M

    2012-06-15

    Two derivatives of thiosemicarbazide were prepared. Their complexes were prepared using Mn(II) and Cu(II) salts. All the isolated complexes are characterized using the following spectra: IR, UV-Vis, Mass, (1)H NMR and X-ray diffraction. Magnetic measurements and thermal analysis are the other additive tools for complete investigation. Mononuclear and binuclear complexes are proposed based on elemental analysis mainly. The IR spectra offer the mode of coordination of each ligand with each metal ion. The electronic spectra and magnetic measurements are proposing the structural geometry of the investigated complexes. The octahedral geometry proposed for Mn(II) complexes but the square-planar for Cu(II) complexes. The (1)H NMR spectra were done for all organic compounds used in this study and displaying the most suitable tautomer of them. X-ray diffraction of H(2)L(1) and its complexes show their amorphous nature but H(2)L(2) ligand and its complexes show their nanocrystalline nature. The TG analysis was used to prove the presence of solvent molecules attached with the complexes as covalently or physically. Finally, the biological investigation was carried out for H(2)L(2) ligand and its complexes and displaying the inhibition activity of Cu(II) complex than the Mn(II) one.

  3. Spectral, thermal and biological studies of Mn(II) and Cu(II) complexes with two thiosemicarbazide derivatives

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Metwaly, Nashwa M.

    Two derivatives of thiosemicarbazide were prepared. Their complexes were prepared using Mn(II) and Cu(II) salts. All the isolated complexes are characterized using the following spectra: IR, UV-Vis, Mass, 1H NMR and X-ray diffraction. Magnetic measurements and thermal analysis are the other additive tools for complete investigation. Mononuclear and binuclear complexes are proposed based on elemental analysis mainly. The IR spectra offer the mode of coordination of each ligand with each metal ion. The electronic spectra and magnetic measurements are proposing the structural geometry of the investigated complexes. The octahedral geometry proposed for Mn(II) complexes but the square-planar for Cu(II) complexes. The 1H NMR spectra were done for all organic compounds used in this study and displaying the most suitable tautomer of them. X-ray diffraction of H2L1 and its complexes show their amorphous nature but H2L2 ligand and its complexes show their nanocrystalline nature. The TG analysis was used to prove the presence of solvent molecules attached with the complexes as covalently or physically. Finally, the biological investigation was carried out for H2L2 ligand and its complexes and displaying the inhibition activity of Cu(II) complex than the Mn(II) one.

  4. Magnetic, electronic and electrochemical studies of mono and binuclear Cu(II) complexes using novel macrocyclic ligands.

    PubMed

    Gupta, Nidhi; Gupta, Rachna; Chandra, Sulekh; Bawa, S S

    2005-04-01

    A series of new mono and binuclear copper (II) complexes [Cul]X(2)and [Cu(2)lX(2)] where 1 = L(1), L(2) and L(3) are the macrocyclic ligands. In mononuclear complexes the geometry of Cu(II) ion is distorted squareplanar and in binuclear complexes the geometry of Cu(II) is tetragonal. The synthesized complexes were characterized by spectroscopic (IR,UV-vis and ESR) techniques. Electrochemical studies of the complexes reveals that all the mononuclear Cu(II) complexes show a single quasireversible one-electron transfer reduction wave (E(pc) = -0.76 to -0.84V) and the binuclear complexes show two quasireversible one electron transfer reduction waves (E(pc)(1) = -0.86 to -1.01V, E(pc)(2) = -1.11 to -1.43V) in cathodic region. The ESR spectra of mononuclear complexes show four lines with nuclear hyperfine splittings with the observed g(11) values in the ranges 2.20-2.28, g( perpendicular) = 2.01-2.06 and A(11) = 125-273. The binuclear complexes show a broad ESR spectra with g = 2.10-2.11. The room temperature magnetic moment values for the mononuclear complexes are in the range [mu(eff) = 1.70-1.72BM] and for the binuclear complexes the range is [mu(eff) = 1.46-1.59BM].

  5. Very high Cu(II) adsorption efficacy of designed nano-platelet Mg(OH)2 assembly

    NASA Astrophysics Data System (ADS)

    Sekhar Das, Pradip; Bakuli, Suvajit; Samanta, Aniruddha; Mandal, Ashok Kumar; Ghosh, Jiten; Dey, Arjun; Mukhopadhyay, Anoop Kumar

    2017-02-01

    The present work examined the efficacy of designed Mg(OH)2 nano-platelet assembly (DMGHNPA) for toxic Cu(II) waste removal from water. For this purpose, DMGHNPA with surface area as high as 237 m2.g‑1 was synthesized by a very simple and cost effective method at room temperature. The results showed that at concentration range of 80–1000 mg.l‑1, extra-ordinarily high e.g.  >99% Cu(II) ion adsorption efficacy was achieved by the DMGHNPA. Based on the experimental data, adsorption mechanism is proposed to explain the extra-ordinary high adsorption efficacy of the DMGHNPA. The efficient adsorption was occurred through Cu2(NO3)(OH)3 microspheres formation on the surfaces of self-supported DMGHNPA. The implication of such extra-ordinary high adsorption efficacy of the Mg(OH)2 nano-platelet assembly is discussed further in the context of toxic waste e.g. Cu(II) ion removal from water.

  6. Tuning the Reactivity of Radical through a Triplet Diradical Cu(II) Intermediate in Radical Oxidative Cross-Coupling

    PubMed Central

    Zhou, Liangliang; Yi, Hong; Zhu, Lei; Qi, Xiaotian; Jiang, Hanpeng; Liu, Chao; Feng, Yuqi; Lan, Yu; Lei, Aiwen

    2015-01-01

    Highly selective radical/radical cross-coupling is paid more attention in bond formations. However, due to their intrinsic active properties, radical species are apt to achieve homo-coupling instead of cross-coupling, which makes the selective cross-coupling as a great challenge and almost untouched. Herein a notable strategy to accomplish direct radical/radical oxidative cross-coupling has been demonstrated, that is metal tuning a transient radical to a persistent radical intermediate followed by coupling with another transient radical. Here, a transient nitrogen-centered radical is tuned to a persistent radical complex by copper catalyst, followed by coupling with a transient allylic carbon-centered radical. Firstly, nitrogen-centered radical generated from N-methoxybenzamide stabilized by copper catalyst was successfully observed by EPR. Then DFT calculations revealed that a triplet diradical Cu(II) complex formed from the chelation N-methoxybenzamide nitrogen-centered radical to Cu(II) is a persistent radical species. Moreover, conceivable nitrogen-centered radical Cu(II) complex was observed by high-resolution electrospray ionization mass spectrometry (ESI-MS). Ultimately, various allylic amides derivatives were obtained in good yields by adopting this strategy, which might inspire a novel and promising landscape in radical chemistry. PMID:26525888

  7. Investigation of irradiated rats DNA in the presence of Cu(II) chelates of amino acids Schiff bases.

    PubMed

    Karapetyan, N H; Torosyan, A L; Malakyan, M; Bajinyan, S A; Haroutiunian, S G

    2016-01-01

    The new synthesized Cu(II) chelates of amino acids Schiff bases were studied as a potential radioprotectors. Male albino rats of Wistar strain were exposed to X-ray whole-body irradiation at 4.8 Gy. This dose caused 30% mortality of the animals (LD30). The survival of animals exposed to radiation after preliminary administration of 10 mg/kg Cu(II)(Nicotinyl-L-Tyrosinate)2 or Cu(II)(Nicotinyl-L-Tryptophanate)2 prior to irradiation was registered about 80 and 100% correspondingly. Using spectrophotometric melting and agarose gel electrophoresis methods, the differences between the DNA isolated from irradiated rats and rats pretreated with Cu(II) chelates were studied. The fragments of DNA with different breaks were revealed in DNA samples isolated from irradiated animals. While, the repair of the DNA structure was observed for animals pretreated with the Cu(II) chelates. The results suggested that pretreatment of the irradiated rats with Cu(II)(Nicotinyl-L-Tyrosinate)2 and Cu(II)(Nicotinyl-L-Tryptophanate)2 compounds improves the liver DNA characteristics.

  8. Multifunctional Composites of Chiral Valine Derivative Schiff Base Cu(II) Complexes and TiO2

    PubMed Central

    Takeshita, Yuki; Takakura, Kazuya; Akitsu, Takashiro

    2015-01-01

    We have prepared four new Cu(II) complexes containing valine moieties with imidazole ligands at the fourth coordination sites and examined their photo-induced reactions with TiO2 in order of understanding the reaction mechanisms. Under a nitrogen atmosphere, the intermolecular electron transfer reactions (essentially supramolecular interactions) of these systems, which resulted in the reduction of Cu(II) species to Cu(I) ones, occurred after UV light irradiation. In this study, we have investigated the conditions of the redox reactions in view of substituent effects of aldehyde moieties. The results of cyclic voltammetry (CV) on an rotating ring-disk electrode (RRDE) suggested that the substitution effects and redox potentials were correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were also performed to simulate the UV–Vis and circular dichroism (CD) spectra; the results revealed a reasonably good correlation between the substituent effects and the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals (HOMO-LUMO) gaps associated with the most intense transition bands. In addition, we summarized the substitution effects of Cu(II) complexes for their corresponding UV light-induced reactions. PMID:25686033

  9. Multifunctional composites of chiral valine derivative Schiff base Cu(II) complexes and TiO2.

    PubMed

    Takeshita, Yuki; Takakura, Kazuya; Akitsu, Takashiro

    2015-02-12

    We have prepared four new Cu(II) complexes containing valine moieties with imidazole ligands at the fourth coordination sites and examined their photo-induced reactions with TiO2 in order of understanding the reaction mechanisms. Under a nitrogen atmosphere, the intermolecular electron transfer reactions (essentially supramolecular interactions) of these systems, which resulted in the reduction of Cu(II) species to Cu(I) ones, occurred after UV light irradiation. In this study, we have investigated the conditions of the redox reactions in view of substituent effects of aldehyde moieties. The results of cyclic voltammetry (CV) on an rotating ring-disk electrode (RRDE) suggested that the substitution effects and redox potentials were correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were also performed to simulate the UV-Vis and circular dichroism (CD) spectra; the results revealed a reasonably good correlation between the substituent effects and the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals (HOMO-LUMO) gaps associated with the most intense transition bands. In addition, we summarized the substitution effects of Cu(II) complexes for their corresponding UV light-induced reactions.

  10. Photochemical behavior of antibiotics impacted by complexation effects of concomitant metals: a case for ciprofloxacin and Cu(II).

    PubMed

    Wei, Xiaoxuan; Chen, Jingwen; Xie, Qing; Zhang, Siyu; Li, Yingjie; Zhang, Yifei; Xie, Hongbin

    2015-07-01

    Many water bodies, especially those adjacent to aquaculture and livestock breeding areas, are contaminated by both antibiotics and transition metals. However, the effects of the interaction between antibiotics and transition metals on the environmental behavior and the ecotoxicology of antibiotics are largely unknown. We hypothesized that antibiotics may coordinately bind with metal ions, and this complexation may affect the environmental photochemical behavior of antibiotics. We took ciprofloxacin (CIP) and Cu(ii) as a case, and employed simulated sunlight experiments and density functional theory calculations to investigate the underlying reaction mechanisms. The results showed that monovalent cationic ciprofloxacin (H2CIP(+)) that is predominant in the normal pH range (6-9) of surface waters can chelate with hydrated Cu(ii) to form [Cu(H2CIP)(H2O)4](3+). Compared with H2CIP(+), [Cu(H2CIP)(H2O)4](3+) has different molecular orbitals, and atomic charge distribution. As a result, [Cu(H2CIP)(H2O)4](3+) showed dissimilar light absorption properties, slower direct photolytic rates, lower (1)O2 generation ability and weaker reactivity towards (1)O2. Due to the Cu(ii) complexation, the apparent photodegradation of H2CIP(+) was inhibited, and the photolytic pathways and product distribution were altered. This study implies that for an accurate ecological risk assessment of antibiotics under transition metal co-contamination conditions, the effects of metal complexation should be considered.

  11. A click fluorophore sensor that can distinguish Cu(II) and Hg(II) via selective anion-induced demetallation.

    PubMed

    Lau, Yu Heng; Price, Jason R; Todd, Matthew H; Rutledge, Peter J

    2011-03-01

    A cyclam-based fluorescent sensor featuring a novel triazole pendant arm has been synthesised using click chemistry. The sensor is highly responsive to both Cu(II) and Hg(II) in neutral aqueous solution and displays excellent selectivity in the presence of various competing metal ions in 50-fold excess. The addition of specific anions such as I(-) and S(2)O(3)(2-) causes a complete revival of fluorescence only in the case of Hg(II), providing a simple and effective method for distinguishing solutions containing Cu(II), Hg(II) or a mixture of both ions, even in doped seawater samples. X-ray crystal structures of both the Hg(II) sensor complex and a model Cu(II) complex show that pendant triazole coordination occurs through the central nitrogen atom (N2), providing to the best of our knowledge the first reported examples of this unusual coordination mode in macrocycles. Fluorescence, mass spectrometry and (1)H NMR experiments reveal that the mechanism of anion-induced fluorescence revival involves either displacement of pendant coordination or complete removal of the Hg(II) from the macrocycle, depending on the anion.

  12. Structural models for Cu(II) bound to the fragment 92-96 of the human prion protein.

    PubMed

    Grande-Aztatzi, Rafael; Rivillas-Acevedo, Lina; Quintanar, Liliana; Vela, Alberto

    2013-01-24

    The prion protein (PrP(C)) binds Cu(II) in its N-terminal region, and it is associated to a group of neurodegenerative diseases termed transmissible spongiform encephalopaties (TSEs). The isoform PrP(Sc), derived from the normal PrP(C), is the pathogenic agent of TSEs. Using spectroscopic techniques (UV-vis absorption, circular dichroism, and electron paramagnetic resonance) and electronic structure calculations, we obtained a structural description for the different pH-dependent binding modes of Cu(II) to the PrP(92-96) fragment. We have also evaluated the possibility of water molecule ligation to the His96-bound copper ion. Geometry-optimized structural models that reproduce the spectroscopic features of these complexes are presented. Two Cu(II) binding modes are relevant at physiological pH: 4N and 3NO equatorial coordination modes; these are best described by models with no participation of water molecules in the coordination sphere of the metal ion. In contrast, the 2N2O and N3O coordination modes that are formed at lower pH involve the coordination of an axial water molecule. This study underscores the importance of including explicit water molecules when modeling copper binding sites in PrP(C).

  13. Synthesis and adsorption of silica gel modified 3-aminopropyltriethoxysilane (APTS) from corn cobs against Cu(II) in water

    NASA Astrophysics Data System (ADS)

    Purwanto, Agung; Yusmaniar, Ferdiani, Fatmawati; Damayanti, Rachma

    2017-03-01

    Silica gel modified APTS was synthesized from silica gel which was obtained from corn cobs via sol-gel process. Silica gel was synthesized from corn cobs and then chemically modified with silane coupling agent which has an amine group (NH2). This process resulting modified silica gel 3-aminopropyltriethoxysilane (APTS). Characterization of silica gel modified APTS by SEM-EDX showed that the size of the particles of silica gel modified APTS was 20µm with mass percentage of individual elements were nitrogen (N) 15.56%, silicon (Si) 50.69% and oxygen (O) 33.75%. In addition, silica gel modified APTS also showed absorption bands of functional groups silanol (Si-OH), siloxane (Si-O-Si), and an aliphatic chain (-CH2-), as well as amine (NH2) from FTIR spectra. Based on the characterization of XRD, silica gel 2θ of 21.094° and 21.32° respectively. It indicated that both material were amorphous. Determination of optimum pH and contact time on adsorption of silica gel 3-aminopropyltriethoxysilane (APTS) against Cu(II). The optimum pH and contact time was measured by using AAS. Optimum pH of adsorption silica gel modified APTS against metal Cu(II) could be obtained at pH 6 while optimum contact time was at 30 minutes, with the process of adsorption metal Cu(II) occured based on the model Freundlich isotherm.

  14. Removal of Cu(II) from aqueous solution using synthetic poly(catechol-diethylenetriamine-p-phenylenediamine) particles.

    PubMed

    Liu, Qiang; Liu, Qinze; Ruan, Zining; Chang, Xiaoqing; Yao, Jinshui

    2016-07-01

    A novel poly(catechol-diethylenetriamine-pphenylenediamine)(PCEA) adsorbent was synthesized in methanol, with chelating groups supplied by catechol and diethylenetriamine, which showed a strong removal performance and efficient adsorption toward Cu(II) ions in aqueous solution. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Besides, factors such as adsorbent dosage, pH, initial ionic and metal concentrations, contact time, and temperature on the adsorption of Cu(II) were studied. The data revealed that the adsorption followed a pseudo-second order kinetic model and the adsorption rate was influenced by the intra-particle diffusion. Furthermore, the adsorption process followed the Langmuir isotherm model, and the maximum adsorption capacity (Qm) was 44.2mg/g at 298K in simulated wastewater. The value of ΔG (kJ/mol) and ΔH (kJ/mol) also demonstrated that the adsorption process was spontaneous and endothermic. Studies revealed that PCEA particles were powerful and stable for the removal of Cu(II) in water, and it could be directly applied to the Cu(II)-contaminated water.

  15. Complexation of Cu(II) by original tartaric acid-based ligands in nonionic micellar media: thermodynamic study and applications.

    PubMed

    Dupont-Leclercq, Laurence; Giroux, Sébastien; Parant, Stéphane; Khoudour, Leïla; Henry, Bernard; Rubini, Patrice

    2009-04-09

    The complexation of Cu(II) with original alkylamidotartaric acids (C(x)T) is investigated in homogeneous aqueous medium and in the presence of nonionic micelles of Brij 58 (C16EO20), thanks to various analytical techniques such as NMR self-diffusion experiments, CD and UV-vis spectroscopy, ESI mass spectrometry, pHmetry and micellar-enhanced ultrafiltration (MEUF). First, a complete speciation study proves the formation of dimeric complexes in water and provides their formation constants. Second, a similar study is led in the presence of nonionic micelles. It underlines a modification of the apparent equilibrium constants in micellar medium and demonstrates that the structure of the complexes is slightly modified in the presence of micelles. This thermodynamic and structural study is applied to modelize the evolution of the extraction yields of Cu(II) by the micelles as a function of pH and to identify the complexes extracted in the micelles. The effects of the chain length of the ligand (C3T vs C8T) on the solubilization properties are put into relief and discussed. Anionic species are proved to be more incorporated in the nonionic micelles than the cationic species. The extracting system constituted of octylamidotartaric acid (CsT) solubilized in nonionic micelles of Brij 58 is demonstrated to be very efficient for the extraction of Cu(II) by MEUF, this technique being an interesting green alternative to traditional solvent extraction.

  16. Ditopic receptors containing urea groups for solvent extraction of Cu(ii) salts.

    PubMed

    Carreira-Barral, Israel; Mato-Iglesias, Marta; de Blas, Andrés; Platas-Iglesias, Carlos; Tasker, Peter A; Esteban-Gómez, David

    2017-02-21

    The ditopic receptor L3 [1-(2-((7-(4-(tert-butyl)benzyl)-1,4,7,10-tetraazacyclododecan-1-yl)methyl)phenyl)-3-(3-nitrophenyl)urea] containing a macrocyclic cyclen unit for Cu(ii)-coordination and a urea moiety for anion binding was designed for recognition of metal salts. The X-ray structure of [CuL3(SO4)] shows that the sulfate anion is involved in cooperative binding via coordination to the metal ion and hydrogen-bonding to the urea unit. This behaviour is similar to that observed for the related receptor L1 [1-(2-((bis(pyridin-2-ylmethyl)amino)methyl)phenyl)-3-(3-nitrophenyl)urea], which forms a dimeric [CuL1(μ-SO4)]2 structure in the solid state. In contrast, the single crystal X-ray structure of [ZnL3(NO3)2] contains a 1 : 2 complex (metal : anion) where one anion coordinates to the metal and the other is hydrogen-bonded to the urea group. Spectrophotometric titrations performed for the [CuL3(OSMe2)](2+) complex indicate that this system is able to bind a wide range of anions with an affinity sequence: MeCO2(-) > Cl(-) > H2PO4(-) > Br(-) > NO2(-) > HSO4(-) > NO3(-). Lipophilic analogues of L1 and L3 extract CuSO4 and CuCl2 from water into chloroform with high selectivity over the corresponding Co(ii), Ni(ii) and Zn(ii) salts.

  17. Role of DDL processes during electrolytic reduction of Cu(II) in a low oxygen environment.

    PubMed

    Brosky, Rebekah T; Pamukcu, Sibel

    2013-11-15

    Heavy metals typically accumulate in reduced bottom sediments after being discharged into waterways by industrial and municipal processes. A laboratory experiment was conducted in order to determine if abundance of clay in the bottom sediments of a Cu-contaminated aqueous ecosystem could enhance electrolytic reduction of the heavy metal. Cu(NO3)2 · 2.5H2O was added to simulate a moderately contaminated system with 650 μg Cu/ml kaolinite clay-water slurry. A constant electrical potential of 1.0 V/cm was applied across platinum wire electrodes inserted into the continuously stirred system for four days while the system ORP(2) was monitored and periodic sub-samples were taken for analysis. The electrical as well as the chemical results indicate that the quantity of Cu(II) being reduced to Cu(I), especially within the aqueous phase, is increased within the first 48 h of experimentation by the presence of kaolinite clay up to 0.05 mg clay/l slurry.

  18. SOD-Mimic Cu(II) Dimeric Complexes Involving Kinetin and Its Derivative: Preparation and Characterization

    PubMed Central

    Novotná, Radka; Trávníček, Zdeněk; Herchel, Radovan

    2012-01-01

    Two SOD-mimic active dimeric Cu(II) chlorido complexes of the compositions [Cu2(μ-HL1)4Cl2]Cl2 (1) and [Cu2(μ-HL2)2(μ-Cl)2(HL2)2Cl2] · 4H2O (2) involving the cosmetologically relevant cytokinin kinetin (N6-furfuryladenine, HL1) and its derivative N6-(5-methylfurfuryl)adenine (HL2) have been synthesized and characterized by elemental analysis, infrared, and electronic spectroscopy, ESI+ mass spectrometry, conductivity and temperature dependence of magnetic susceptibility measurements, and thermogravimetric (TG) and differential thermal (DTA) analyses. The results of these methods, particularly the temperature dependence of magnetic susceptibility, showed the complexes to be dimeric with a strong antiferromagnetic exchange (J = −290 cm−1 for complex 1 and J = −160 cm−1 for 2). The complexes have been identified as auspicious SOD-mimics, as their antiradical activity evaluated by the in vitro SOD-mimic assay resulted in the IC50 values equal to 8.13 μM (1) and 0.71 μM (2). PMID:22966218

  19. Sequestering of Cu(II) from aqueous solution using cassava peel (Manihot esculenta).

    PubMed

    Kosasih, Aline Natasia; Febrianto, Jonathan; Sunarso, Jaka; Ju, Yi-Hsu; Indraswati, Nani; Ismadji, Suryadi

    2010-08-15

    Cassava peel is a prospective cheap biosorbent for metal ions sequestration. In this research, the ability of cassava peel to remove Cu(II) from aqueous solution was evaluated. Its physical characteristics were probed by nitrogen adsorption measurements and scanning electron microscopy while its biosorption mechanism was studied by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy/Energy Dispersive using X-ray analysis-(SEM/EDX), X-ray mapping and X-ray Photoelectron Spectroscopy (XPS). Biosorption experiments were carried out isothermally at three different temperatures (30 degrees C, 45 degrees C and 60 degrees C) in a static mode. The maximum adsorption capacity (41.77 mg g(-1)) was attained at the highest temperature. The pH and particle size effects in relation to biosorption capacity were also discussed. In addition, Langmuir, Freundlich, Sips and Toth equations were tested for data correlation. Langmuir and Freundlich models were the best choices since they contained less parameter with equally good fitting performance in comparison to the other three parameters equations. For kinetic studies, sorption rates were better represented using a pseudo second-order expression in comparison to a more commonly used pseudo first-order equation. Also, thermodynamic variables showed that the process was spontaneous (DeltaG<0), endothermic (DeltaH>0) and irreversible (DeltaS>0).

  20. Ferrocenyl-substituted dinuclear Cu(II) complex: Synthesis, spectroscopy, electrochemistry, DFT calculations and catecholase activity

    NASA Astrophysics Data System (ADS)

    Emirik, Mustafa; Karaoğlu, Kaan; Serbest, Kerim; Menteşe, Emre; Yilmaz, Ismail

    2016-02-01

    A new ferrocenyl-substituted heterocyclic hydrazide ligand and its Cu(II) complex were prepared. The DFT calculations were performed to determine the electronic and molecular structures of the title compounds. The electronic spectra were calculated by using time-dependent DFT method, and the transitions were correlated with the molecular orbitals of the compounds. The bands assignments of IR spectra were achieved in the light of the theoretical vibrational spectral data and total energy distribution values calculated at DFT/B3LYP/6-311++G(d,p) level. The redox behaviors of the ferrocene derivatives were investigated by cyclic voltammetry. The compounds show reversible redox couple assignable to Fc+/Fc couple. The copper(II) complex behaves as an effective catalyst towards oxidation of 3,5-di-tert-butylcatechol to its corresponding quinone derivative in DMF saturated with O2. The reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers 2.32 × 103.

  1. Behavior of human immunoglobulin G adsorption onto immobilized Cu(II) affinity hollow-fiber membranes.

    PubMed

    Borsoi-Ribeiro, Mariana; Bresolin, Igor Tadeu Lazzarotto; Vijayalakshmi, Mookambeswaran; Bueno, Sônia Maria Alves

    2013-10-01

    Iminodiacetic acid (IDA) and tris(2-aminoethyl)amine (TREN) chelating ligands were immobilized on poly(ethylene vinyl alcohol) (PEVA) hollow-fiber membranes after activation with epichlorohydrin or butanediol diglycidyl ether (bisoxirane). The affinity membranes complexed with Cu(II) were evaluated for adsorption of human immunoglobulin G (IgG). The effects of matrix activation and buffer system on adsorption of IgG were studied. Isotherms of batch IgG adsorption onto finely cut membranes showed that neither of the chelates, IDA-Cu(II) or TREN-Cu(II), had a Langmuirean behavior with negative cooperativity for IgG binding. A comparison of equilibrium and dynamic maximum capacities showed that the dynamic capacity for a mini-cartridge in a cross-flow filtration mode (52.5 and 298.4 mg g(-1) dry weight for PEVA-TREN-Cu(II) and PEVA-IDA-Cu(II), respectively) was somewhat higher than the equilibrium capacity (9.2 and 73.3 mg g(-1) dry weight for PEVA-TREN-Cu(II) and PEVA-IDA-Cu(II), respectively). When mini-cartridges were used, the dynamic adsorption capacity of IDA-Cu(II) was the same for both mini-cartridge and agarose gel.

  2. A set of robust fluorescent peptide probes for quantification of Cu(ii) binding affinities in the micromolar to femtomolar range.

    PubMed

    Young, Tessa R; Wijekoon, Chathuri J K; Spyrou, Benjamin; Donnelly, Paul S; Wedd, Anthony G; Xiao, Zhiguang

    2015-03-01

    Reliable quantification of copper binding affinities and identification of the binding sites provide a molecular basis for an understanding of the nutritional roles and toxic effects of copper ions. Sets of chromophoric probes are now available that can quantify Cu(i) binding affinities from nanomolar to attomolar concentrations on a unified scale under in vitro conditions. Equivalent probes for Cu(ii) are lacking. This work reports development of a set of four fluorescent dansyl peptide probes (DP1-4) that can quantify Cu(ii) binding affinities from micromolar to femtomolar concentrations, also on a unified scale. The probes were constructed by conjugation of a dansyl group to four short peptides of specific design. Each was characterised by its dissociation constant KD, its pH dependence and the nature of its binding site. One equivalent of Cu(ii) is bound by the individual probes that display different and well-separated affinities at pH 7.4 (log KD = -8.1, -10.1, -12.3 and -14.1, respectively). Intense fluorescence is emitted at λmax ∼ 550 nm upon excitation at ∼330 nm. Binding of Cu(ii) quenches the fluorescence intensity linearly until one equivalent of Cu(ii) is bound. Multiple approaches and multiple affinity standards were employed to ensure reliability. Selected examples of application to well-characterised Cu(ii) binding peptides and proteins are presented. These include Aβ16 peptides, two naturally occurring Cu(ii)-chelating motifs in human serum and cerebrospinal fluid with sequences GHK and DAHK and two copper binding proteins, CopC from Pseudomonas syringae and PcoC from Escherichia coli. Previously reported affinities are reproduced, demonstrating that peptides DP1-4 form a set of robust and reliable probes for Cu(ii) binding to peptides and protein targets.

  3. Utilization of Mg2Al-layered double hydroxide as an effective sequestrator to trap Cu(II) ions from aqueous solution impacted by water quality parameters

    NASA Astrophysics Data System (ADS)

    Xu, Meng; Linghu, Wensheng; Hu, Jun; Jiang, Gongyi; Sheng, Jiang

    2016-11-01

    Recently, Mg2Al-layered double hydroxide (Mg2Al-LDH) has been extensively studied as promising candidates to trap metal ions due to their high complexation and adsorption capacity. Herein, Mg2Al-LDH was utilized as an effectiveness sequestrator to trap Cu(II) ions from aqueous solution by an adsorption process using batch technique under ambient conditions. The results showed that Cu(II) adsorption on Mg2Al-LDH increases with pH increasing and maintains a high level at pH>7.0. The adsorption of Cu(II) was obviously affected by ionic strength at low pH, which was not dependent on ionic strength at high pH. The presence of HA or FA promotes the adsorption of Cu(II) on Mg2Al-LDH at low pH values, while reduces the adsorption of Cu(II) at high pH values. The adsorption isotherms of Cu(II) on Mg2Al-LDH at three different temperatures were simulated by the Langmuir, Freundlich, and Dubinin-Radushkevitch (D-R) models very well. The thermodynamic parameters were determined from the temperature-dependent adsorption, and the results showed that Cu(II) adsorption on Mg2Al-LDH was exothermic and the process was favored at high temperature. The results suggest that Mg2Al-LDH is suitable as a sorbent material for the recovery and attenuation of Cu(II)-polluted wastewater.

  4. Adsorption of As(III), As(V) and Cu(II) on zirconium oxide immobilized alginate beads in aqueous phase.

    PubMed

    Kwon, Oh-Hun; Kim, Jong-Oh; Cho, Dong-Wan; Kumar, Rahul; Baek, Seung Han; Kurade, Mayur B; Jeon, Byong-Hun

    2016-10-01

    A composite adsorbent to remove arsenite [As(III)], arsenate [As(V)], and copper [Cu(II)] from aqueous phase was synthesized by immobilizing zirconium oxide on alginate beads (ZOAB). The composition (wt%) of ZOAB (Zr-34.0; O-32.7; C-21.3; Ca-1.0) was confirmed by energy dispersive X-ray (EDX) analysis. Sorption studies were conducted on single and binary sorbate systems, and the effects of contact time, initial adsorbate concentration, and pH on the adsorption performance of ZOAB (pHPZC = 4.3) were monitored. The sorption process for As(III)/As(V) and Cu(II) reached an equilibrium state within 240 h and 24 h, respectively, with maximum sorption capacities of 32.3, 28.5, and 69.9 mg g(-1), respectively. The addition of Cu(II) was favorable for As(V) sorption in contrast to As(III). In the presence of 48.6 mg L(-1) Cu(II), the sorption capacity of As(V) increased from 1.5 to 3.8 mg g(-1) after 240 h. The sorption data for As(III)/As(V) and Cu(II) conformed the Freundlich and Langmuir isotherm models, respectively. The adsorption of As(III), As(V), and Cu(II) followed pseudo second order kinetics. The effect of arsenic species on Cu(II) sorption was insignificant. The results of present study demonstrated that the synthesized sorbent could be useful for the simultaneous removal of both anionic and cationic contaminants from wastewaters.

  5. Adsorption phenomena of cubane-type tetranuclear Ni(II) complexes with neutral, thioether-functionalized ligands on Au(111)

    NASA Astrophysics Data System (ADS)

    Heß, Volkmar; Matthes, Frank; Bürgler, Daniel E.; Monakhov, Kirill Yu.; Besson, Claire; Kögerler, Paul; Ghisolfi, Alessio; Braunstein, Pierre; Schneider, Claus M.

    2015-11-01

    The controlled and intact deposition of molecules with specific properties onto surfaces is an emergent field impacting a wide range of applications including catalysis, molecular electronics, and quantum information processing. One strategy is to introduce grafting groups functionalized to anchor to a specific surface. While thiols and disulfides have proven to be quite effective in combination with gold surfaces, other S-containing groups have received much less attention. Here, we investigate the surface anchoring and organizing capabilities of novel charge-neutral heterocyclic thioether groups as ligands of polynuclear nickel(II) complexes. We report on the deposition of a cubane-type {Ni4} (= [Ni(μ3-Cl)Cl(HL·S)]4) single-molecule magnet from dichloromethane solution on a Au(111) surface, investigated by scanning tunneling microscopy, X-ray photoelectron spectroscopy, and low-energy electron diffraction, both immediately after deposition and after subsequent post-annealing. The results provide strong evidence for partial decomposition of the coordination complex upon deposition on the Au(111) surface that, however, leaves the magnetic {Ni4Cl4n} (n = 1 or 2) core intact. Only post-annealing above 480 K induces further decomposition and fragmentation of the {Ni4Cl4n} core. The detailed insight into the chemisorption-induced decomposition pathway not only provides guidelines for the deposition of thioether-functionalized Ni(II) complexes on metallic surfaces but also reveals opportunities to use multidentate organic ligands decorated with thioether groups as transporters for highly unstable inorganic structures onto conducting surfaces, where they are stabilized retaining appealing electronic and magnetic properties.

  6. Magnetic Anisotropy in Pentacoordinate Ni(II) and Co(II) Complexes: Unraveling Electronic and Geometrical Contributions.

    PubMed

    Cahier, Benjamin; Perfetti, Mauro; Zakhia, Georges; Naoufal, Daoud; El-Khatib, Fatima; Guillot, Régis; Rivière, Eric; Sessoli, Roberta; Barra, Anne-Laure; Guihéry, Nathalie; Mallah, Talal

    2017-03-13

    The magnetic properties of the pentacoordinate [M(II) (Me4 cyclam)N3 ](+) (Me4 cyclam=tetramethylcyclam; N3 =azido; M=Ni, Co) complexes were investigated. Magnetization and EPR studies indicate that they have an easy plane of magnetization with axial anisotropy parameters D close to 22 and greater than 30 cm(-1) for the Ni and Co complexes, respectively. Ab initio calculations reproduced the experimental values of the zero-field splitting parameters and allowed the orientation of the anisotropy tensor axes with respect to the molecular frame to be determined. For M=Ni, the principal anisotropy axis lies along the Ni-Nazido direction perpendicular to the Ni(Me4 cyclam) mean plane, whereas for M=Co it lies in the Co(Me4 cyclam) mean plane and thus perpendicular to the Co-Nazido direction. These orientations match one of the possible solutions experimentally provided by single-crystal cantilever torque magnetometry. To rationalize the geometry and its impact on the orientation of the anisotropy tensor axis, calculations were carried out on model complexes [Ni(II) (NCH)5 ](2+) and [Co(II) (NCH)5 ](2+) by varying the geometry between square pyramidal and trigonal bipyramidal. The geometry of the complexes was found to be the result of a compromise between the electronic configuration of the metal ion and the structure-orienting effect of the Me4 cyclam macrocycle. Moreover, the orientation of the anisotropy axes is mainly dependent on the geometry of the complexes.

  7. Relationship between Ni(II) and Zn(II) Coordination and Nucleotide Binding by the Helicobacter pylori [NiFe]-Hydrogenase and Urease Maturation Factor HypB*

    PubMed Central

    Sydor, Andrew M.; Lebrette, Hugo; Ariyakumaran, Rishikesh; Cavazza, Christine; Zamble, Deborah B.

    2014-01-01

    The pathogen Helicobacter pylori requires two nickel-containing enzymes, urease and [NiFe]-hydrogenase, for efficient colonization of the human gastric mucosa. These enzymes possess complex metallocenters that are assembled by teams of proteins in multistep pathways. One essential accessory protein is the GTPase HypB, which is required for Ni(II) delivery to [NiFe]-hydrogenase and participates in urease maturation. Ni(II) or Zn(II) binding to a site embedded in the GTPase domain of HypB modulates the enzymatic activity, suggesting a mechanism of regulation. In this study, biochemical and structural analyses of H. pylori HypB (HpHypB) revealed an intricate link between nucleotide and metal binding. HpHypB nickel coordination, stoichiometry, and affinity were modulated by GTP and GDP, an effect not observed for zinc, and biochemical evidence suggests that His-107 coordination to nickel toggles on and off in a nucleotide-dependent manner. These results are consistent with the crystal structure of HpHypB loaded with Ni(II), GDP, and Pi, which reveals a nickel site distinct from that of zinc-loaded Methanocaldococcus jannaschii HypB as well as subtle changes to the protein structure. Furthermore, Cys-142, a metal ligand from the Switch II GTPase motif, was identified as a key component of the signal transduction between metal binding and the enzymatic activity. Finally, potassium accelerated the enzymatic activity of HpHypB but had no effect on the other biochemical properties of the protein. Altogether, this molecular level information about HpHypB provides insight into its cellular function and illuminates a possible mechanism of metal ion discrimination. PMID:24338018

  8. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    SciTech Connect

    Taha, Mohd F. Shaharun, Maizatul S.; Shuib, Anis Suhaila Borhan, Azry

    2014-10-24

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  9. Remarkable Features of the McMurry Reaction Conditions in Dimerization of Formyl- and 2-Formylvinylpurpurinimides. Electrochemistry of Monomeric Ni(II) Purpurinimide and the Corresponding Dyads

    PubMed Central

    Goswami, Lalit N.; Ethirajan, Manivannan; Dobhal, Mahabeer P.; Zhang, Min; Missert, Joseph R.; Shibata, Masayuki; Kadish, Karl M.; Pandey, Ravindra K.

    2009-01-01

    To investigate the electrochemical properties of purpurinimide dyads and electron transfer sites for their reduction and oxidation, a series of dimers with variable C-C linkages were synthesized. For the preparation of these novel structures, the formyl and 2-formylvinyl substituents were regioselectively introduced at positions-3 and 20 of Ni(II) purpurinimides by the Vilsmeier reaction. The Ni(II) complexes were then subjected to the McMurry reaction under two different conditions with unexpected results being obtained. For example, the reaction of formyl purpurinimides with TiCl3(DME)1.5 failed to produce the desired C-C dimers and the starting compounds were recovered almost quantitatively. Under similar reaction conditions, the 20-(2-formylvinyl)purpurinimide also did not dimerize but gave instead unexpected benzoisobacteriochlorins via an intramolecular cyclization. However, treatment of the 3-formyl- and 20-formyl-purpurinimides with TiCl4/Zn gave the corresponding dimers linked with one double bond (trans-) in modest yields. Under similar conditions, Ni(II) purpurinimides containing a 2-formylvinyl substituent either at position-3 or position-20 afforded the respective C-C dimers, where the purpurinimide moieties were joined with a trans-trans-trans- hexatriene linker. Molecular modeling data suggest that the nature of the conformational energy difference found in all trans- vs. trans-cis-trans- conformers of the dimers connected by a hexatriene linker at the meso- or β-position of the macrocycle is not due to the intrinsic conformational energy difference of the linker region, which is identical for both dimers. PMID:19072690

  10. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    NASA Astrophysics Data System (ADS)

    Taha, Mohd F.; Shuib, Anis Suhaila; Shaharun, Maizatul S.; Borhan, Azry

    2014-10-01

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m2/g and 0.17 cm2/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  11. Binding of Cu(II) to human alpha-synucleins: comparison of wild type and the point mutations associated with the familial Parkinson's disease.

    PubMed

    Hong, Lian; Simon, John D

    2009-07-16

    The Cu(II)-alpha-synuclein interaction has been invoked as an important process in the pathogenesis of Parkinson's disease. Herein, we report binding constants and stoichiometry under near-physiological conditions for the binding of Cu(II) to human alpha-synuclein. Specifically, we compare the binding of Cu(II) to wild-type (WT) protein and two separate single mutation proteins that are associated with familial Parkinson's diseases: A30P and A53T. Cu(II) binds to all three alpha-synuclein proteins with a 1:1 stoichiometry. The Cu(II) binding constants, however, vary among the proteins studied. Cu(II) binding to WT and A53T at 37 degrees C is similar with a pH-dependent binding constant (K) of approximately 2.4 x 10(9) and approximately 4.8 x 10(9) M(-1) at pH 7.2 and 7.4, respectively. Cu(II) binding to A30P, however, exhibits two binding constants. The major binding site of A30P, characteristic of >90% of the bound Cu(II), has binding constants of 1.6 x 10(9) and 3.6 x 10(9) M(-1) at pH 7.2 and 7.4, respectively, slightly lower ( approximately 70%) than that characteristic of WT or A53T at the corresponding pH. The second less populated binding exhibited by A30P has a large binding constant, approximately 10(10) M(-1). Our size exclusion analysis ruled out the contribution of protofibrils to the strong Cu(II) binding. Previous studies indicated that A30P had a larger proportion of intermediate species (e.g., small oligomeric species, such as dimers and trimers) relative to WT and A53T. Thus, we propose that the high affinity site is attributed to the binding of Cu(II) to those small oligomeric species.

  12. Both Met(109) and Met(112) Are Utilized For Cu(II) Coordination By The Amyloidogenic Fragment of The Human Prion Protein at Physiological pH

    PubMed Central

    Shearer, Jason; Soh, Pamela; Lentz, Stefanie

    2008-01-01

    The prion protein is a ubiquitous neuronal membrane protein. Misfolding of the prion protein has been implicated in transmissible spongiform encephalopathies (prion diseases). It has been demonstrated that the human prion protein (PrP) is capable of coordinating at least five CuII ions under physiological conditions; four copper binding sites can be found in the octarepeat domain between residues 61 – 91, while another copper binding site can be found in the unstructured “amyloidogenic” domain between residues 91 – 126 (PrP(91–126). Herein we expand upon a previous study (J. Shearer, P. Soh, Inorg. Chem. 46 (2007) 710–719) where we demonstrated that the physiologically relevant high affinity CuII coordination site within PrP(91–126) is found between residues 106–114. It was shown that CuII is contained within a square planar (N/O)3S coordination environment with one His imidazole ligand (H(111)) and one Met thioether ligand (either M(109) or M(112)). The identity of the Met thioether ligand was not identified in that study. In this study we perform a detailed investigation of the CuII coordination environment within the PrP fragment containing residues 106–114 (PrP(106–114)) involving optical, X-ray absorption, EPR, and fluorescence spectroscopies in conjunction with electronic structure calculations. By using derivatives of PrP(106–114) with systematic Met → Ile “mutations” we show that the CuII coordination environment within PrP(106–114) is actually comprised of a mixture of two major species; one CuII(N/O)3S center with the M(109) thioether coordinated to CuII and another CuII(N/O)3S center with the M(112) thioether coordinated to CuII. Furthermore, deletion of one or more Met residues from the primary sequence of PrP(106–114) both reduces the CuII affinity of the peptide by two to seven fold, and renders the resulting CuII metallopeptides redox inactive. The biological implications of these findings are discussed. PMID:18778855

  13. Synthesis, characterization, computational studies, antimicrobial activities and carbonic anhydrase inhibitor effects of 2-hydroxy acetophenone-N-methyl p-toluenesulfonylhydrazone and its Co(II), Pd(II), Pt(II) complexes

    NASA Astrophysics Data System (ADS)

    Özbek, Neslihan; Alyar, Saliha; Memmi, Burcu Koçak; Gündüzalp, Ayla Balaban; Bahçeci, Zafer; Alyar, Hamit

    2017-01-01

    2-Hydroxyacetophenone-N-methyl p-toluenesulfonylhydrazone (afptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Co(II), Pd(II), Pt(II) complexes were synthesized for the first time. Synthesized compounds were characterized by spectroscopic methods (FT-IR, 1Hsbnd 13C NMR, LC-MS, UV-vis), magnetic susceptibility and conductivity measurements. 1H and 13C shielding tensors for crystal structure of ligand were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments were performed at B3LYP/6-311++G(d,p) theory level combined with scaled quantum mechanics force field (SQMFF) methodology. The antibacterial activities of synthesized compounds were studied against some Gram positive and Gram negative bacteria by using microdilution and disc diffusion methods. In vitro enzyme inhibitory effects of the compounds were measured by UV-vis spectrophotometer. The enzyme activities against human carbonic anhydrase II (hCA II) were evaluated as IC50 (the half maximal inhibitory concentration) values. It was found that afptsmh and its metal complexes have inhibitory effects on hCA II isoenzyme. General esterase activities were determined using alpha and beta naphtyl acetate substrates (α- and β-NAs) of Drosophila melanogaster (D. melanogaster). Activity results show that afptsmh does not strongly affect the bacteria strains and also shows poor inhibitory activity against hCAII isoenzyme whereas all complexes posses higher biological activities.

  14. Vibrational study of new Pt(II) and Pd(II) complexes with functionalized nitrogen-containing tertiary phosphine oxides. Ab initio study of ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline.

    PubMed

    Trendafilova, N; Bauer, G; Georgieva, I; Tosheva, T; Varbanov, S

    2003-01-01

    Vibrational study of new Pt(II) and Pd(II) complexes of functionalized nitrogen-containing tertiary phosphine oxides, namely ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline (o-, m- and p-dpmoa), (CH3)2P(O)CH2OC6H4NH2, have been presented. Geometry optimization of the ligands was performed at HF/6-31G* and B3LYP/6-31G* levels of the theory. Harmonic frequencies were calculated at HF/6-31G* optimized geometries. Relative gas-phase and solution-phase (H2O and CH3CN) basicities of o-, m- and p-dpmoa ligands have been determined by ab initio calculations at STO-3G level with the Onsager reaction field model. On the basis of the vibrational study, physical and analytical data it was suggested that the ligands in the complexes studied coordinate through the amino group and form square-planar platinum and palladium complexes of the general formula ML2Cl2 (M = Pt, Pd, L = o-, m- and p-dpmoa).

  15. Vibrational study of new Pt(II) and Pd(II) complexes with functionalized nitrogen-containing tertiary phosphine oxides. Ab initio study of ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline

    NASA Astrophysics Data System (ADS)

    Trendafilova, N.; Bauer, G.; Georgieva, I.; Tosheva, T.; Varbanov, S.

    2003-01-01

    Vibrational study of new Pt(II) and Pd(II) complexes of functionalized nitrogen-containing tertiary phosphine oxides, namely ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline ( o-, m- and p-dpmoa), (CH 3) 2P(O)CH 2OC 6H 4NH 2, have been presented. Geometry optimization of the ligands was performed at HF/6-31G* and B3LYP/6-31G* levels of the theory. Harmonic frequencies were calculated at HF/6-31G* optimized geometries. Relative gas-phase and solution-phase (H 2O and CH 3CN) basicities of o-, m- and p-dpmoa ligands have been determined by ab initio calculations at STO-3G level with the Onsager reaction field model. On the basis of the vibrational study, physical and analytical data it was suggested that the ligands in the complexes studied coordinate through the amino group and form square-planar platinum and palladium complexes of the general formula ML 2Cl 2 (M=Pt, Pd, L= o-, m- and p-dpmoa).

  16. Effect of carboxyethylation degree on the adsorption capacity of Cu(II) by N-(2-carboxyethyl)chitosan from squid pens.

    PubMed

    Huang, Jun; Xie, Haihua; Ye, Hui; Xie, Tian; Lin, Yuecheng; Gong, Jinyan; Jiang, Chengjun; Wu, Yuanfeng; Liu, Shiwang; Cui, Yanli; Mao, Jianwei; Mei, Lehe

    2016-03-15

    Chitosan was prepared by N-deacetylation of squid pens β-chitin, and N-carboxyethylated chitosan (N-CECS) with different degrees of substitution (DS) were synthesized. DS values of N-CECS derivatives calculated by (1)H nuclear magnetic resonance (NMR) spectroscopy were 0.60, 1.02 and 1.46, respectively. The adsorption capacity of Cu(II) by N-CECS correlated well with the DS and pH ranging from 3.2 to 5.8. The maximum Cu(II) adsorption capacity (qm) of all three N-CECS at pH 5.4 was 207.5mg g(-1), which was 1.4-fold higher than that of chitosan. The adsorption equilibrium process was better described by the Langmuir than Freundlich isotherm model. Adsorption of Cu(II) ion onto N-CECS followed a pseudo-second order mechanism with chemisorption as the rate-limiting step. In a ternary adsorption system, the adsorption capacity of Cu(II) by N-CECS also presented high values, and qm for Cu(II), Cd(II), and Pb(II) were 150.2, 28.8, and 187.9mg g(-1), respectively.

  17. A theoretical analysis of the coordination modes of CuII with penicillins: activation of the beta-lactam C-N bond.

    PubMed

    Campomanes, Pablo; Menéndez, M Isabel; López, Ramón; Sordo, Tomás L

    2005-02-01

    The interaction of CuII with 6-formylamino-3alpha-carboxypenam and 6-acetylamino-3alpha-carboxypenam was investigated by means of DFT calculations with the UB3LYP functional. Nine different modes of complexation between CuII and 6-formylamino-3alpha-carboxypenam were located. When two water molecules directly bonded to CuII are included in the calculations on 6-acetylamino-3alpha-carboxypenam as penicillin model, only six CuII(H2O)2-6-acetylamino-3alpha-carboxypenam complexes (1S-6S) are found. In solution the four most stable complexes obtained from our calculations, 6S, 1S, 2S, and 3S, exhibit CuII in square-planar coordination with at least one bond to the carboxylate group, in agreement with experimental evidence. Complexes 6S, 1S, and 3S were previously suggested by available experimental evidence. In three of the most stable complexes (6S, 2S, and 3S) the beta-lactam C-N bond is remarkably activated and displays C-N bond lengths similar to those found in some tetrahedral intermediates located for the hydrolysis of 2-azetidinones. This suggests that these kinds of complexes belong to the reaction coordinate for the degradation of beta-lactam antibiotics in the presence of CuII.

  18. Spectroscopic evidence on improvement in complex formation of O2N2 aza-crown macrocyclic ligands with Cu(II) acetate upon incorporation with [60]Fullerene

    NASA Astrophysics Data System (ADS)

    Ghanbari, Bahram; Gholamnezhad, Parisa

    2016-12-01

    The present paper reports the spectroscopic investigations on the complexation of Cu(II) with two macrocyclic ligands bonded to [60]Fullerene (L1 and L2) measured in N-methylpyrrolidone (NMP) as solvent. On the basis of UV-vis-NIR spectroscopy applying Jobs method of continuous variation, typical 1:1 stoichiometries were established for the complexes of Cu(II) with L1, and L2. DFT calculations suggested that superior HOMO distributions spread over the nitrogen-donor (as well as somehow oxygen- donor in L2) groups of L1 and L2 macrocycles were the key factor for the observed Kb value enhancement. Thermodynamic stabilities for these complexes have also been determined employing Benesi-Hildebrand equation and the results were compared in terms of their calculated binding constants (Kb). These measurements showed that L1 and L2 bound to these cations stronger than their parent free macrocyclic ligands 1 and 2, respectively. Furthermore, Kb values found for L2 complexes revealed that it could coordinate Cu(II) cation better than L1. Thermodynamic parameters (ΔG, ∆ H, and - ΔS) derived from Van't Hoff equation showed that L1 and L2 coordination of Cu(II) cation were occurred due to both enthalpic and entropic factors while the coordination of Cu(II) with their parent macrocyclic ligands 1 and 2 only enjoyed from only enthalpic advantages.

  19. Statistical Analysis of Main and Interaction Effects on Cu(II) and Cr(VI) Decontamination by Nitrogen–Doped Magnetic Graphene Oxide

    NASA Astrophysics Data System (ADS)

    Hu, Xinjiang; Wang, Hui; Liu, Yunguo

    2016-10-01

    A nitrogen–doped magnetic graphene oxide (NMGO) was synthesized and applied as an adsorbent to remove Cu(II) and Cr(VI) ions from aqueous solutions. The individual and combined effects of various factors (A: pH, B: temperature, C: initial concentration of metal ions, D: CaCl2, and E: humic acid [HA]) on the adsorption were analyzed by a 25‑1 fractional factorial design (FFD). The results from this study indicated that the NMGO had higher adsorption capacities for Cu(II) ions than for Cr(VI) ions under most conditions, and the five selected variables affected the two adsorption processes to different extents. A, AC, and C were the very important factors and interactions for Cu(II) adsorption. For Cr(VI) adsorption, A, B, C, AB, and BC were found to be very important influencing variables. The solution pH (A) was the most important influencing factor for removal of both the ions. The main effects of A–E on the removal of Cu(II) were positive. For Cr(VI) adsorption, the main effects of A and D were negative, while B, C, and E were observed to have positive effects. The maximum adsorption capacities for Cu(II) and Cr(VI) ions over NMGO were 146.365 and 72.978 mg/g, respectively, under optimal process conditions.

  20. Cu(II) salen complex with propylene linkage: An efficient catalyst in the formation of Csbnd X bonds (X = N, O, S) and biological investigations

    NASA Astrophysics Data System (ADS)

    Azam, Mohammad; Dwivedi, Sourabh; Al-Resayes, Saud I.; Adil, S. F.; Islam, Mohammad Shahidul; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Lee, Dong-Ung

    2017-02-01

    The catalytic property of a mononuclear Cu(II) salen complex in Chan-Lam coupling reaction with phenyl boronic acid at room temperature is reported. The studied complex is found to be potential catalyst in the preparation of carbon-heteroatom bonds with excellent yields. The studied Cu(II) salen complex is monoclinic with cell parameters, a = 9.6807(5) (α 90°), (b = 17.2504(8) (β 112.429 (2), c = 11.1403 (6) (γ = 90°), and has distorted square planar environment around Cu(II) ion. Furthermore, there is no π⋯π interactions in the reported complex due to large distance between the centroid of aromatic rings. In addition, DNA binding study of Cu(II) salen complex by fluorescence and absorption spectroscopy is also reported. Moreover, the reported Cu(II) salen complex exhibits significant anticancer activity against MCF-7 cancer cell lines, and displays potential antimicrobial biofilm activity against P. aeruginosa, suggesting antimicrobial biofilm an important tool for suppression of resistant infections caused by P. aeruginosa.

  1. Statistical Analysis of Main and Interaction Effects on Cu(II) and Cr(VI) Decontamination by Nitrogen–Doped Magnetic Graphene Oxide

    PubMed Central

    Hu, Xinjiang; Wang, Hui; Liu, Yunguo

    2016-01-01

    A nitrogen–doped magnetic graphene oxide (NMGO) was synthesized and applied as an adsorbent to remove Cu(II) and Cr(VI) ions from aqueous solutions. The individual and combined effects of various factors (A: pH, B: temperature, C: initial concentration of metal ions, D: CaCl2, and E: humic acid [HA]) on the adsorption were analyzed by a 25−1 fractional factorial design (FFD). The results from this study indicated that the NMGO had higher adsorption capacities for Cu(II) ions than for Cr(VI) ions under most conditions, and the five selected variables affected the two adsorption processes to different extents. A, AC, and C were the very important factors and interactions for Cu(II) adsorption. For Cr(VI) adsorption, A, B, C, AB, and BC were found to be very important influencing variables. The solution pH (A) was the most important influencing factor for removal of both the ions. The main effects of A–E on the removal of Cu(II) were positive. For Cr(VI) adsorption, the main effects of A and D were negative, while B, C, and E were observed to have positive effects. The maximum adsorption capacities for Cu(II) and Cr(VI) ions over NMGO were 146.365 and 72.978 mg/g, respectively, under optimal process conditions. PMID:27694891

  2. Separation and sequential recovery of tetracycline and Cu(II) from water using reusable thermo-responsive chitosan-based flocculant.

    PubMed

    Ren, Kexin; Du, Hongwei; Yang, Zhen; Tian, Ziqi; Zhang, Xuntong; Yang, Weiben; Chen, Jianqiang

    2017-02-27

    Coexistence of antibiotics and heavy metals is typically detected in water containing both organic and inorganic contaminants. In this work, flocculation method, using a reusable thermal-responsive chitosan-based flocculant (CS-g-PNNPAM), was applied for separation and sequential recovery of tetracycline (TC) and Cu(II) from water. High synergistic removal rates of both TC and Cu(II) from water (>90%) were reached. Interactive effects among targeted water's temperature (T1), stock solution's temperature (T2) and flocculant dosage on flocculation performance were assessed using response surface methodology. In order to optimize flocculation, operation strategies of adjusting T2 and dosage according to T1, based on the interactive effects, were given through mathematical analyses. Flocculation mechanism, as well as interfacial interactions among CS-g-PNNPAM, TC and Cu(II), was studied through experimental investigations (floc size monitoring, XPS and UV spectra) and theoretical calculations (density functional theory (DFT) and molecular dynamics (MD) simulations): Coordination of Cu(II) with TC and the flocculant promoted flocculation; switchable interactions (H-bonds and hydrophobic association) of TC-flocculant at different temperatures were key factors affecting operation strategies. By weaken these interactions step by step, TC and Cu(II) were sequentially recovered from flocs using certain solutions. Meanwhile, the flocculant in flocs was regenerated and found reusable with high flocculation efficiency.

  3. Removal of Pb(II) and Cu(II) from aqueous solution using multiwalled carbon nanotubes/iron oxide magnetic composites.

    PubMed

    Hu, Jun; Zhao, Donglin; Wang, Xiangke

    2011-01-01

    Multiwalled carbon nanotubes (MWCNTs)/iron oxide magnetic composites (named as MCs) were prepared by co-precipitation method, and were characterised by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in detail. The prepared MCs were employed as an adsorbent for the removal of Pb(II) and Cu(II) ions from wastewater in heavy metal ion pollution cleanup. The results demonstrated that the sorption of Pb(II) and Cu(II) ions was strongly dependent on pH and temperature. The experimental data were well described by Langmuir model, and the monolayer sorption capacity of MCs was found to vary from 10.02 to 31.25 mg/g for Pb(II) and from 3.11 to 8.92 mg/g for Cu(II) at temperature increasing from 293.15 to 353.15 K at pH 5.50. The sorption capacity of Pb(II) on MCs was higher than that of Cu(II), which was attributed to their ionic radius, hydration energies and hydrolysis of their hydroxides. The thermodynamic parameters (i.e., ΔH(0), ΔS(0) and ΔG(0)) were calculated from temperature dependent sorption isotherms, and the results indicated that the sorption of Pb(II) and Cu(II) ions on MCs were spontaneous and endothermic processes.

  4. Adsorption of Pb(II) and Cu(II) from aqueous solution on magnetic porous ferrospinel MnFe2O4.

    PubMed

    Ren, Yueming; Li, Nan; Feng, Jing; Luan, Tianzhu; Wen, Qing; Li, Zhanshuang; Zhang, Milin

    2012-02-01

    The adsorption of Pb(II) and Cu(II) from aqueous solution on magnetic porous ferrospinel MnFe(2)O(4) prepared by a sol-gel process was investigated. Single batch experiment was employed to test pH effect, sorption kinetics, and isotherm. The interaction mechanism and the regeneration were also explored. The results showed that Pb(II) and Cu(II) removal was strongly pH-dependent with an optimum pH value of 6.0, and the equilibrium time was 3.0 h. The adsorption process could be described by a pseudo-second-order model, and the initial sorption rates were 526.3 and 2631.5 μmol g(-1)min(-1) for Pb(II) and Cu(II) ions, respectively. The equilibrium data were corresponded well with Langmuir isotherm, and the maximum adsorption capacities were 333.3 and 952.4 μmol g(-1) for Pb(II) and Cu(II) ions, respectively. The adsorbed Pb(II) and Cu(II) ions were in the form of the complex with oxygen in carboxyl and hydroxyl groups binding on the surface of magnetic porous MnFe(2)O(4). The sorbent could be reused for five times with high removal efficiency.

  5. A novel reusable nanocomposite adsorbent, xanthated Fe3O4-chitosan grafted onto graphene oxide, for removing Cu(II) from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Jinshui; Liu, Wenxiu; Wang, Yiru; Xu, Meijiao; Wang, Bin

    2016-03-01

    Novel nanocomposites of xanthated Fe3O4-chitosan grafted onto graphene oxide (xanthated Fe3O4-CS-GO) were successfully synthesized for the first time using an amidation reaction. The xanthated Fe3O4-CS-GO was used to remove Cu(II) from aqueous solutions. The xanthated Fe3O4-CS-GO was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and energy dispersive X-ray spectroscopy. The Cu(II) adsorption isotherms for the xanthated Fe3O4-CS-GO fitted the Langmuir isotherm model. The maximum Cu(II) adsorption capacity of the xanthated Fe3O4-CS-GO was 426.8 mg g-1, which is much higher than the maximum adsorption capacities of other adsorbents that have been described in the literature. This was attributed to xanthated Fe3O4-CS-GO having abundant functional groups. The xanthated Fe3O4-CS-GO could be regenerated using ethylene diamine tetraacetic acid, and could easily be removed from a liquid using an external magnetic field. These features would allow secondary pollution of the environment to be avoided more easily than is the case for other adsorbents. Cu(II) was adsorbed from aqueous solutions quickly and efficiently by the xanthated Fe3O4-CS-GO complex, suggesting that xanthated Fe3O4-CS-GO may be an ideal candidate for removing Cu(II) from wastewater.

  6. Crystal structures, DNA-binding and cytotoxic activities studies of Cu(II) complexes with 2-oxo-quinoline-3-carbaldehyde Schiff-bases.

    PubMed

    Liu, Zeng-Chen; Wang, Bao-Dui; Li, Bo; Wang, Qin; Yang, Zheng-Yin; Li, Tian-Rong; Li, Yong

    2010-11-01

    Three novel 2-oxo-quinoline-3-carbaldehyde Schiff-bases and their Cu(II) complexes were synthesized. The molecular structures of Cu(II) complexes were determined by X-ray crystal diffraction. The DNA-binding modes of the complexes were also investigated by UV-vis absorption spectrum, fluorescence spectrum, viscosity measurement and EB-DNA displacement experiment. The experimental evidences indicated that the ligands and Cu(II) complexes could interact with CT-DNA (calf-thymus DNA) through intercalation, respectively. Comparative cytotoxic activities of ligands and Cu(II) complexes were also determined by MTT [3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide] and SRB (sulforhodamine B) methods. The results showed that the three Cu(II) complexes exhibited more effective cytotoxic activity against HL60 cells and HeLa cells than corresponding ligands. Also, CuL(3) showed higher cytotoxic activity than CuL(1) and CuL(2).

  7. Structural basis for the inhibition of truncated islet amyloid polypeptide aggregation by Cu(II): insights into the bioinorganic chemistry of type II diabetes.

    PubMed

    Rivillas-Acevedo, Lina; Sánchez-López, Carolina; Amero, Carlos; Quintanar, Liliana

    2015-04-20

    Type 2 diabetes (T2D) is one of the most common chronic diseases, affecting over 300 million people worldwide. One of the hallmarks of T2D is the presence of amyloid deposits of human islet amyloid polypeptide (IAPP) in the islets of Langerhans of pancreatic β-cells. Recent reports indicate that Cu(II) can inhibit the aggregation of human IAPP, although the mechanism for this inhibitory effect is not clear. In this study, different spectroscopic techniques and model fragments of IAPP were employed to shed light on the structural basis for the interaction of Cu(II) with human IAPP. Our results show that Cu(II) anchors to His18 and the subsequent amide groups toward the C-terminal, forming a complex with an equatorial coordination mode 3N1O at physiological pH. Cu(II) binding to truncated IAPP at the His18 region is the key event for its inhibitory effect in amyloid aggregation. Electron paramagnetic resonance studies indicate that the monomeric Cu(II)-IAPP(15-22) complex differs significantly from Cu(II) bound to mature IAPP(15-22) fibers, suggesting that copper binding to monomeric IAPP(15-22) competes with the conformation changes needed to form β-sheet structures, thus delaying fibril formation. A general mechanism is proposed for the inhibitory effect of copper and other imidazole-binding metal ions in IAPP amyloid formation, providing further insights into the bioinorganic chemistry of T2D.

  8. Improving the separation of Cu(II) from Zn(II) based on an anion exchanger for the preparation a 62Zn/62Cu generator.

    PubMed

    El-Azony, K M

    2011-09-01

    A separation procedure of (64,67)Cu(II) from (65)Zn(II) was studied for serving (62)Zn/(62)Cu generator preparation. The distribution coefficients of (65)Zn(II) and (64,67)Cu(II) ions from homogeneous medium of hydrochloric acid and acetone onto De-Acidite FF anion exchanger were investigated. Both hydrochloric acid and acetone concentrations are important factors that affect the separation process. Effects of decreasing the HCl concentration from 0.2 to 0.04 M, increasing the acetone concentration from 5% to 80% and different acetone concentrations (5-97%) in 0.2M HCl were also studied on the separation of (64,67)Cu(II) from (65)Zn(II). The exchange capacity of Zn(II) on the De-Acidite FF matrix was obtained as 3.8 meq/g and the(64,67)Cu(II) elution efficiency was 92.5% using 20 ml of 0.2M HCl-60% acetone with flow rate of 2 ml/min.The radionuclidic purity and radiochemical purity of the eluted (64,67)Cu(II) were examined.

  9. Valorization of Romanian silver fir tree bark (Abies alba Mill.) wastes as low-cost sorbent of Cu(II) ions from polluted waters.

    PubMed

    Tofan, Lavinia; Paduraru, Carmen; Amalinei, Roxana Laura Mihailescu; Bunia, Ion; Miron, Anca

    2016-11-01

    Considering recycling as the first option in the hierarchy of sustainable waste management, and also the demand for efficient processes for wastewater treatment with reduced costs, the potential applicability of Romanian Abies alba bark, the main waste from the industrial processing of the wood of mature silver fir trees, as sorbent for Cu(II) has been studied in batch conditions. It was observed that the extent of Cu(II) sorption is strongly dependent on initial solution pH, sorbent dose, initial Cu(II) ion concentration, temperature and contact time. Equilibrium data fitted very well with both Langmuir and Freundlich isotherm models. The Langmuir maximum sorption capacity of Cu(II) ions on Abies alba bark waste was found to be 7.80 mg/g at 293 K. Kinetic studies showed a high affinity of the sorption experimental data to the pseudo-second order model. Gibbs free energy was spontaneous for all interactions and the sorption process exhibited endothermic enthalpy value. The waste of Abies alba bark was successfully used for the sorption removal of Cu(II) ions from industrial electroplating wastewaters.

  10. MEKC determination of vanadium from mineral ore and crude petroleum oil samples using precapillary chelation with bis(salicylaldehyde)tetramethyl-ethylenediimine.

    PubMed

    Mirza, Muhammad Aslam; Kandhro, Abdul Jabbar; Khuhawar, Muhammad Yar; Arain, Rafee

    2009-09-01

    An analytical procedure has been developed for the separation of Cu(II), Ni(II), Co(II), Fe(II), Pd(II), Th(IV), V(IV), and determination of Fe(II), Co(II), Ni(II), and V(IV) by MEKC after chelation with bis(salicylaldehyde)tetramethylethylenediimine (H(2)SA(2)Ten). Uncoated fused silica capillary was used with an applied voltage of 30 kV with photo-diode array detection at 228 nm. SDS was added as micellar medium at pH 8.2 with sodium tetraborate buffer (0.1 M). Linear calibrations were established within 0.015-1000 microg/mL of each element with LOD within 5-67 ng/mL. The method was applied for the determination of vanadium from crude oil and ore samples in the range 0.34-2.40 and 114.2-720.7 microg/g with RSD 1.7-3.8 and 0.98-2.30% (n = 3), respectively. Fe, Ni, and Co present in crude oil and ore samples were also determined with RSD 1.3-2.8, 1.1-4.1, and 1.2-3.5% (n = 3), respectively. The results were compared with that of supplier's specifications and atomic absorption spectrometry (AAS). Method was evaluated by standard addition technique.

  11. 2,4-Dinitrophenylhydrazine functionalized sodium dodecyl sulfate-coated magnetite nanoparticles for effective removal of Cd(II) and Ni(II) ions from water samples.

    PubMed

    Sobhanardakani, Soheil; Zandipak, Raziyeh

    2015-07-01

    2,4-Dinitrophenylhydrazine immobilized on sodium dodecyl sulfate (SDS)-coated magnetite and was used for removal of Cd(II) and Ni(II) ions from aqueous solution. The prepared product was characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The size of the nanoparticles according to SEM was obtained around 20-35 nm. In batch tests, the effects of pH, contact time, initial metal concentration, and temperature were studied. The kinetic and equilibrium data were modeled with recently developed models. The adsorption kinetics and isotherms were well fitted by the fractal-like pseudo-second-order model and Langmuir-Freundlich model, respectively. Maximum adsorption capacity by this adsorbent is 255.1 mg g(-1) for Cd(II) ion and 319.6 mg g(-1) for Ni(II) ion at pH 7.0 and 25 °C. The method was successfully applied to the removal of metal cations in real samples (tap water, river water, and petrochemical wastewater).

  12. Iminodiacetic acid functionalized cation exchange resin for adsorptive removal of Cr(VI), Cd(II), Ni(II) and Pb(II) from their aqueous solutions.

    PubMed

    Misra, R K; Jain, S K; Khatri, P K

    2011-01-30

    Iminodiacetic acid functionality has been introduced on styrene-divinyl benzene co-polymeric beads and characterized by FT-IR in order to develop weak acid based cation exchange resin. This resin was evaluated for the removal of different heavy metal ions namely Cd(II), Cr(VI), Ni(II) and Pb(II) from their aqueous solutions. The results showed greater affinity of resin towards Cr(VI) for which 99.7% removal achieved in optimal conditions following the order Ni(II)>Pb(II)>Cd(II) with 65%, 59% and 28% removal. Experiments were also directed towards kinetic studies of adsorption and found to follow first order reversible kinetic model with the overall rate constants 0.3250, 0.2393, 0.4290 and 0.2968 for Cr(VI), Ni(II), Pb(II) and Cd(II) removal respectively. Detailed studies of Cr(VI) removal has been carried out to see the effect of pH, resin dose and metal ion concentration on adsorption and concluded that complexation enhanced the chromium removal efficacy of resin drastically, which is strongly pH dependent. The findings were also supported by the comparison of FT-IR spectra of neat resin with the chromium-adsorbed resin.

  13. Competitive adsorption of Cd(II), Zn(II) and Ni(II) from their binary and ternary acidic systems using tourmaline.

    PubMed

    Liu, Haibin; Wang, Cuiping; Liu, Jingting; Wang, Baolin; Sun, Hongwen

    2013-10-15

    The adsorption of Cd(II), Zn(II) and Ni(II) from aqueous solutions in binary and ternary component systems by tourmaline was investigated. Kinetic data were accurately fitted to pseudo-second order and internal diffusion models, which indicated that the adsorption of heavy metals occurred on the interior surface of the sorbent and internal diffusion was the controlling mechanism during heavy metal ion adsorption but was not the only rate-controlling step. Additionally, tourmaline had a very good adsorption capacity for Cd(II), Zn(II) and Ni(II) in multi-component aqueous solutions at strongly acidic pH values (in contrast to industrial wastewater pH values). This good adsorption capacity is attributed to the fact that tourmaline can automatically adjust the pH values of acidic (except pH 2.0 and 3.0), neutral or alkaline aqueous solutions to 6.0. Adsorption isotherms and separation factors showed that tourmaline displays a high selectivity toward one metal in a two-component or a three-component system with an affinity order of Cd(II) > Zn(II) > Ni(II). Thermodynamic parameters indicated that heavy metal adsorption was feasible, spontaneous, and endothermic. Therefore, tourmaline should be explored as a material for removing pollutants from the strongly acidic wastewater.

  14. Ni(II) and Zn(II) complexes of 2-((thiophen-2-ylmethylene)amino)benzamide: synthesis, spectroscopic characterization, thermal, DFT and anticancer activities.

    PubMed

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S

    2015-01-05

    The paper presents the synthesis of Ni(II) and Zn(II) complexes of general composition M(L)X₂ and M(L)₂X₂ (M=Ni(II), Zn(II), X=Cl(-1), OAc(-1)) with Schiff base obtained through the condensation of 2-aminobenzamide with thiophene-2-carbaldehyde. The characterization of newly formed complexes was done by (1)H NMR, UV-VIS, TGA, IR, mass spectrophotometry and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies a distorted octahedral geometry has been assigned for Ni(II) complexes and tetrahedral geometry for Zn(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (HepG2) were studied and compared with those of free ligand.

  15. Investigation of antitumor potential of Ni(II) complexes with tridentate PNO acylhydrazones of 2-(diphenylphosphino)benzaldehyde and monodentate pseudohalides.

    PubMed

    Čobeljić, Božidar; Milenković, Milica; Pevec, Andrej; Turel, Iztok; Vujčić, Miroslava; Janović, Barbara; Gligorijević, Nevenka; Sladić, Dušan; Radulović, Siniša; Jovanović, Katarina; Anđelković, Katarina

    2016-04-01

    Square-planar azido Ni(II) complex with condensation product of 2-(diphenylphosphino)benzaldehyde and Girard's T reagent was synthesized and its crystal structure was determined. Cytotoxic activity of the azido complex and previously synthesized isothiocyanato, cyanato and chlorido Ni(II) complexes with this ligand was examined on six tumor cell lines (HeLa, A549, K562, MDA-MB-453, MDA-MB-361 and LS-174) and two normal cell line (MRC-5 and BEAS-2B). All the investigated nickel(II) complexes were cytotoxic against all tumor cell lines. The newly synthesized azido complex showed selectivity to HeLa and A549 tumor cell lines compared to the normal cells (for A549 IC50 was similar to that of cisplatin). Azido complex interferes with cell cycle phase distribution of A549 and HeLa cells and possesses nuclease activity towards supercoiled DNA. The observed selectivity of the azido complex for some tumor cell lines can be connected with its strong DNA damaging activity.

  16. Importance of nanoparticle size in colorimetric and SERS-based multimodal trace detection of Ni(II) ions with functional gold nanoparticles.

    PubMed

    Krpetić, Zeljka; Guerrini, Luca; Larmour, Iain A; Reglinski, John; Faulds, Karen; Graham, Duncan

    2012-03-12

    Colorimetric detection of analytes using gold nanoparticles along with surface-enhanced Raman spectroscopy (SERS) are areas of intense research activity since they both offer sensing of very low concentrations of target species. Multimodal detection promotes the simultaneous detection of a sample by a combination of different techniques; consequently, surface chemistry design in the development of multimodal nanosensors is important for rapid and sensitive evaluation of the analytes by diverse analytical methods. Herein it is shown that nanoparticle size plays an important role in the design of functional nanoparticles for colorimetric and SERS-based sensing applications, allowing controlled nanoparticle assembly and tunable sensor response. The design and preparation of robust nanoparticle systems and their assembly is reported for trace detection of Ni(II) ions as a model system in an aqueous solution. The combination of covalently attached nitrilotriacetic acid moieties along with the L-carnosine dipeptide on the nanoparticle surface represents a highly sensitive platform for rapid and selective detection of Ni(II) ions. This systematic study demonstrates that significantly lower detection limits can be achieved by finely tuning the assembly of gold nanoparticles of different core sizes. The results clearly demonstrate the feasibility and usefulness of a multimodal approach.

  17. Cassava root husks powder as green adsorbent for the removal of Cu(II) from natural river water

    NASA Astrophysics Data System (ADS)

    Jorgetto, A. O.; Silva, R. I. V.; Saeki, M. J.; Barbosa, R. C.; Martines, M. A. U.; Jorge, S. M. A.; Silva, A. C. P.; Schneider, J. F.; Castro, G. R.

    2014-01-01

    Through a series of simple processes, cassava root husks were turned into a fine powder of controlled particle size (63-75 μm). FTIR spectrum demonstrated the existence of alcohol, amine and carboxylic groups; and elemental analysis confirmed the presence of elements of interest such as sulphur, nitrogen and oxygen. Cross-polarized {1H}sbnd 13C NMR technique indicated the existence of methionine and thiamine through the signals observed at 55 ppm and 54 ppm, respectively, and the point of zero charge (pHpzc) was achieved at pH 5.2. The material was applied in solid-phase extraction of Cu(II) via batch experiments. Optimum adsorption pH was found to be in range of 3-6 and in the kinetic experiment the equilibrium was attained in 1 min. The highest adsorption capacity was 0.14 mmol g-1. The adsorption data were fit to the modified Langmuir equation, and the maximum amount of metal species extracted from the solution, Ns, was determined to be ∼0.14 mmol g-1, which is an indicative that the main adsorption mechanism is through chemisorption. Under optimized conditions, the material was utilized in preconcentration experiments, which culminated in an enrichment factor of 41.3-fold. With the aid of the enrichment factor, experiments were carried out to determine the Cu(II) content in tap water and natural water. Preconcentration method was also applied to a certified reference material (1643e) and the concentration found was 23.03 ± 0.79 μg L-1, whereas the specified Cu(II) concentration was 22.7 ± 0.31 μg L-1.

  18. Synthesis, spectroscopic and electrochemical studies of N,N-bis[(E)-2-thienylmethylidene]-1,8-naphthalenediamine and its Cu(II) complex: DNA cleavage and generation of superoxide anion.

    PubMed

    Shakir, Mohammad; Azam, Mohammad; Ullah, M F; Hadi, S M

    2011-09-02

    A novel tetradentate Cu(II) complex of the type, [CuL](NO(3))(2) was synthesized by the interaction of Schiff base ligand, N,N-bis[(E)-2-thienylmethylidene]-1,8-naphthalenediamine, L obtained by the condensation of thiophene-2-carboxaldehyde and 1,8-diaminonaphthalene. The formation of Schiff base ligand, L and its Cu(II) complex was confirmed on the basis of results of elemental analyses, mass, FT-IR, (1)H and (13)C{(1)H} NMR spectral studies. UV-Vis, EPR and magnetic susceptibility data support a square planar environment around Cu(II) ion. However, molar conductance values confirmed 1:2 electrolytic nature for the Cu(II) complex. The electrochemical studies of Cu(II) complex was carried out by using cyclic voltammetry which revealed the complex to exhibit quasi reversible process. The biological activity of Cu(II) complex such as ability to bind DNA and DNA cleavage were studied where the Cu(II) complex was shown to cause considerable DNA cleavage and also generated reactive oxygen species such as superoxide anion. Since it is known that various anticancer drugs act through induction of oxidative stress that is mediated by reactive oxygen species, our results suggest a putative role of Cu(II) complex similar to various anticancer drugs.

  19. Organic acids pretreatment effect on Rosa bourbonia phyto-biomass for removal of Pb(II) and Cu(II) from aqueous media.

    PubMed

    Manzoor, Qaisar; Nadeem, Raziya; Iqbal, Munawar; Saeed, Rashid; Ansari, Tariq M

    2013-03-01

    The sorption of Pb(II) and Cu(II) form aqueous media by Rosa bourbonia waste phyto-biomass (RBWPB) pretreated with organic acids was investigated as a function of biosorbent dosage, initial metal ions concentration and contact time. The equilibrium biosorption data was analyzed using two kinetic models (pseudo-first order and pseudo-second order) and two isotherm models (Langmuir and Freundlich). The RBWPB was successfully applied for sequestration of both heavy metal ions; however, organic acids pretreatments decreased the metal adsorption capacity of RBWPB. The Langmuir model fitted well to the data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of Pb(II) and Cu(II) metal ions. Gibbs free energy indicated the spontaneous adsorption of Pb(II) and Cu(II) onto RBWPB.

  20. Interplay between lattice, orbital, and magnetic degrees of freedom in the chain-polymer Cu(II) breathing crystals

    NASA Astrophysics Data System (ADS)

    Streltsov, S. V.; Petrova, M. V.; Morozov, V. A.; Romanenko, G. V.; Anisimov, V. I.; Lukzen, N. N.

    2013-01-01

    The chain-polymer Cu(II) “breathing crystals” C21H19CuF12N4O6 were studied using the x-ray diffraction and ab initio band structure calculations. We show that the crystal structure modification at T=146 K, associated with the spin crossover transition, induces the changes of the orbital order in half of the Cu sites. This in turn results in the switch of the magnetic interaction sign in accordance with the Goodenough-Kanamori-Andersen theory of the coupling between the orbital and spin degrees of freedom.

  1. A Colorimetric and Luminescent Dual-Modal Assay for Cu(II) Ion Detection Using an Iridium(III) Complex

    PubMed Central

    Ma, Dik-Lung; He, Hong-Zhang; Chan, Daniel Shiu-Hin; Wong, Chun-Yuen; Leung, Chung-Hang

    2014-01-01

    A novel iridium(III) complex-based chemosensor bearing the 5,6-bis(salicylideneimino)-1,10-phenanthroline ligand receptor was developed, which exhibited a highly sensitive and selective color change from colorless to yellow and a visible turn-off luminescence response upon the addition of Cu(II) ions. The interactions of this iridium(III) complex with Cu2+ ions and thirteen other cations have been investigated by UV-Vis absorption titration, emission titration, and 1H NMR titration. PMID:24927177

  2. Speciation of the new ligand di-isopropyliminodiacetoamide with Cu(II) using computational processing and graphical methods.

    PubMed

    Bernabé-Pineda, Margarita; Ramírez-Silva, María Teresa; Tapia-Benavides, Rafael; Rojas-Hernández, Alberto

    2004-04-01

    The importance assigned to chelating agents in diverse areas has impelled studies concerning their development as related to metal ions representing a biological concern. The synthesis of di-isopropyliminodiacetoamide (D) is presented in this work. The acidity constant obtained for D was pKa = 5.79 +/- 0.04 with the aid of program SUPERQUAD. The equilibrium constants for D with Cu(II) were obtained with the aid of program SQUAD for CuD2+ and CuD2(2)+ species giving log beta1 = 4.795 +/- 0.002 and log beta2 = 8.374 +/- 0.004, respectively.

  3. Revealing the halide effect on the kinetics of the aerobic oxidation of Cu(I) to Cu(II)

    SciTech Connect

    Deng, Yi; Zhang, Guanghui; Qi, Xiaotian; Liu, Chao; Miller, Jeffrey T.; Kropf, A. Jeremy; Bunel, Emilio E.; Lan, Yu; Lei, Aiwen

    2015-01-01

    In situ infrared (IR) and X-ray absorption near-edge structure (XANES) spectroscopic investigations reveal that different halide ligands have distinct effects on the aerobic oxidation of Cu(I) to Cu(II) in the presence of TMEDA (tetramethylethylenediamine). The iodide ligand gives the lowest rate and thus leads to the lowest catalytic reaction rate of aerobic oxidation of hydroquinone to benzoquinone. Further DFT calculations suggest that oxidation of CuI–TMEDA involves a side-on transition state, while oxidation of CuCl–TMEDA involves an end-on transition state which has a lower activation energy.

  4. Dependency of simultaneous Cr(VI), Cu(II) and Cd(II) reduction on the cathodes of microbial electrolysis cells self-driven by microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Yu, Lihua; Wu, Dan; Huang, Liping; Zhou, Peng; Quan, Xie; Chen, Guohua

    2015-01-01

    Microbial fuel cells (MFCs) using either Cr(VI) (MFCsCr) or Cu(II) (MFCsCu) as a final electron acceptor, are stacked to self-drive microbial electrolysis cells (MECs) using Cd(II) (MECsCd) as an electron acceptor for simultaneous reduction of Cr(VI) in MFCsCr, Cu(II) in MFCsCu and Cd(II) in MECsCd with no external energy consumption. Titanium sheet (TS) and carbon rod (CR) as the cathodes of MECsCd are assessed for efficient system performance. MFCsCr and MFCsCu in series is superior to the parallel configuration, and higher Cd(II) reduction along with simultaneous Cr(VI) and Cu(II) reduction supports TS function as a good cathode material. Conversely, CR can not entirely proceed Cd(II) reduction in MECsCd despite of more Cr(VI) and Cu(II) reduction in the same serial configuration than either system alone. While a decrease in cathode volume in both MFCsCr and MFCsCu with serial connection benefits to reduction of Cr(VI) in MFCsCr and Cu(II) in MFCsCu, Cd(II) reduction in MECsCd is substantially enhanced under a decrease in cathode volume in individual MFCsCr and serially connected with volume-unchanged MFCsCu. This study demonstrates simultaneous Cr(VI), Cu(II) and Cd(II) recovery from MFCsCr-MFCsCu-MECsCd self-driven system is feasible, and TS as the cathodes of MECsCd is critical for efficient system performance.

  5. New insights into the coordination of Cu(II) by the amyloid-B 16 peptide from Fourier transform IR spectroscopy and isotopic labeling.

    PubMed

    El Khoury, Youssef; Dorlet, Pierre; Faller, Peter; Hellwig, Petra

    2011-12-15

    Alzheimer's disease is a neurodegenerative disorder in which the formation of amyloid-β (Aβ) aggregates plays a causative role. There is ample evidence that Cu(II) can bind to Aβ and modulate its aggregation. Moreover, Cu(II) bound to Aβ might be involved in the production of reactive oxygen species, a process supposed to be involved in the Alzheimer's disease. The native Aβ40 contains a high affinity binding site for Cu(II), which is comprised in the N-terminal portion. Thus, Aβ16 (amino acid 1-16 of Aβ) has often been used as a model for Cu(II)-binding to monomeric Aβ. The Cu(II)-binding to Aβ is pH dependent and at pH 7.4, two different type of Cu(II) coordinations exist in equilibrium. These two forms are predominant at pH 6.5 and pH 9.0. In either form, a variety of studies show that the N-terminal Asp and the three His play a key role in the coordination, although the exact binding of these amino acids has not been addressed. Therefore, we studied the coordination modes of Cu(II) at pH 6.5 and 9.0 with the help of Fourier transform infrared (FTIR) spectroscopy. Combined with isotopic labeling of the amino acids involved in the coordination sphere, the data points toward the coordination of Cu(II) via the carboxylate of Asp1 at both pH values in a pseudobridging monovalent fashion. At low pH, His6 binds copper via Nτ, while His13 and His14 are bound via Nπ. At high pH, direct evidence is given on the coordination of Cu(II) via the Nτ atom of His6. Additionally, this study clearly shows the effect of Cu(II) binding on the protonation state of the His residues where a proton displacement takes places on the nitrogen atoms of the imidazole ring.

  6. Synthesis, characterization and magnetic studies on mono-, di-, and tri-nuclear Cu(ii) complexes of a new versatile diazine ligand.

    PubMed

    Anwar, Muhammad U; Rawson, Jeremy M; Gavey, Emma L; Pilkington, Melanie; Al-Harrasi, Ahmed; Thompson, Laurence K

    2017-02-14

    The synthesis and coordination chemistry of a new open-chain diazine ligand (L4H2) containing bipyridine, oxime and hydrazone functionalities is reported. Reaction of L4H2 with CuCl2·2H2O affords the mononuclear complex [Cu(L4H2)Cl2] (1) in which the ligand acts as a neutral tridentate N,N',N'' donor, whereas treatment with a large excess of CuCl2·2H2O affords the dinuclear complex [Cu2(L4H)Cl3(CH3OH)(H2O)] (2) in which the ligand is singly-deprotonated at the diazine, offering N,N',N'' and N,N' donor sets to two Cu(ii) ions. Reaction with Cu(NO3)2·3H2O yields the trinuclear complex, [Cu3(L4H)2(CH3OH)4(NO3)4] (3) in which the ligand is again singly deprotonated, but now presents a tetradentate N,N',N'',N'''-donor set to the first Cu(ii) and behaves as an N,O-chelate to a second Cu(ii), with a conformational change from cis to trans at the diazine moiety. When the latter reaction is repeated in the presence of a mild base, a second trinuclear complex is isolated, [Cu3(L4)2(CH3CH2OH)](NO3)2 (4) in which both the diazine and oxime functionalities of the ligand are deprotonated which subsequently bridges all three Cu(ii) ions, acting as an N,N',N'' donor to the first Cu(ii), a N,N' donor to a second Cu(ii) (similar to 2) and as a terminal O-donor to a third Cu(ii) ion. The Cu(ii) ions are linked mutually cis via the two-atom diazine bridge in the case of 2 and 4 and trans in the case of 3. Magnetic studies reveal the presence of weak ferromagnetic interactions in 2 (g = 2.2, J/k = +12.8 K) and strong antiferromagnetic interactions in both 3 and 4 (g = 2.093 J/k = -140 K and g = 2.24 J/k = -300 K respectively).

  7. Site-specific interactions of Cu(II) with alpha and beta-synuclein: bridging the molecular gap between metal binding and aggregation.

    PubMed

    Binolfi, Andrés; Lamberto, Gonzalo R; Duran, Rosario; Quintanar, Liliana; Bertoncini, Carlos W; Souza, Jose M; Cerveñansky, Carlos; Zweckstetter, Markus; Griesinger, Christian; Fernández, Claudio O

    2008-09-03

    The aggregation of alpha-synuclein (AS) is a critical step in the etiology of Parkinson's disease (PD) and other neurodegenerative synucleinopathies. Protein-metal interactions play a critical role in AS aggregation and might represent the link between the pathological processes of protein aggregation and oxidative damage. Our previous studies established a hierarchy in AS-metal ion interactions, where Cu(II) binds specifically to the protein and triggers its aggregation under conditions that might be relevant for the development of PD. In this work, we have addressed unresolved structural details related to the binding specificity of Cu(II) through the design of site-directed and domain-truncated mutants of AS and by the characterization of the metal-binding features of its natural homologue beta-synuclein (BS). The structural properties of the Cu(II) complexes were determined by the combined application of nuclear magnetic resonance, electron paramagnetic resonance, UV-vis, circular dichroism spectroscopy, and matrix-assisted laser desorption ionization mass spectrometry (MALDI MS). Two independent, noninteracting copper-binding sites with significantly different affinities for the metal ion were detected in the N-terminal regions of AS and BS. MALDI MS provided unique evidence for the direct involvement of Met1 as the primary anchoring residue for Cu(II) in both proteins. Comparative spectroscopic analysis of the two proteins allowed us to deconvolute the Cu(II) binding modes and unequivocally assign the higher-affinity site to the N-terminal amino group of Met1 and the lower-affinity site to the imidazol ring of the sole His residue. Through the use of competitive chelators, the affinity of the first equivalent of bound Cu(II) was accurately determined to be in the submicromolar range for both AS and BS. Our results prove that Cu(II) binding in the C-terminal region of synucleins represents a nonspecific, very low affinity process. These new insights into the

  8. Comparative DNA binding abilities and phosphatase-like activities of mono-, di-, and trinuclear Ni(II) complexes: the influence of ligand denticity, metal-metal distance, and coordinating solvent/anion on kinetics studies.

    PubMed

    Bhardwaj, Vimal K; Singh, Ajnesh

    2014-10-06

    Six novel Ni(II) complexes, namely, [Ni2(HL(1))(OAc)2] (1), [Ni3L(1)2]·H2O·2CH3CN (2), [Ni2(L(2))(L(3))(CH3CN)] (3), [Ni2(L(2))2(H2O)2] (4), [Ni2(L(2))2(DMF)2]2·2H2O (5), and [Ni(HL(2))2]·H2O (6), were synthesized by reacting nitrophenol-based tripodal (H3L(1)) and dipodal (H2L(2)) Schiff base ligands with Ni(II) metal salts at ambient conditions. All the complexes were fully characterized with different spectroscopic techniques such as elemental analyses, IR, UV-vis spectroscopy, and electrospray ionization mass spectrometry. The solid-state structures of 2, 3, 5, and 6 were determined using single-crystal X-ray crystallography. The compounds 1, 3, 4, and 5 are dinuclear complexes where the two Ni(II) centers have octahedral geometry with bridging phenoxo groups. Compound 2 is a trinuclear complex with two different types of Ni(II) centers. In compound 3 one of the Ni(II) centers has a coordinated acetonitrile molecule, whereas in compound 4, a water molecule has occupied one coordination site of each Ni(II) center. In complex 5, the coordinated water of complex 4 was displaced by the dimethylformamide (DMF) during its crystallization. Complex 6 is mononuclear with two amine-bis(phenolate) ligands in scissorlike fashion around the Ni(II) metal center. The single crystals of 1 and 4 could not be obtained; however, from the spectroscopic data and physicochemical properties (electronic and redox properties) it was assumed that the structures of these complexes are quite similar to other analogues. DNA binding abilities and phosphatase-like activities of all characterized complexes were also investigated. The ligand denticity, coordinated anions/solvents (such as acetate, acetonitrile, water, and DMF), and cooperative action of two metal centers play a significant role in the phosphate ester bond cleavage of 2-hydroxypropyl-p-nitropenylphosphate by transesterification mechanism. Complex 3 exhibits highest activity among complexes 1-6 with 3.86 × 10(5) times

  9. Spectral characterization and in vitro microbiological activity of new bis-1,8-naphthalimides and their Cu(II) complexes

    NASA Astrophysics Data System (ADS)

    Ottaviani, Maria Francesca; Yordanova, Stanislava; Cangiotti, Michela; Vasileva-Tonkova, Evgenia; Coppola, Concetta; Stoyanov, Stanimir; Grabchev, Ivo

    2016-04-01

    Two novel bis-1,8-naphthalimide derivatives with different substituents at C-4 position, termed L1 and L2, were synthesized and their photophysical properties in organic solvents with different polarity were investigated. Their Cu(II) complexes were also synthesized to be used as antimicrobial agents. The structural properties of [Cu(L1) (NO3)2] and [Cu(L2) (NO3)2] complexes were studied by nuclear magnetic resonance (NMR) and Fourier transform - infrared (FT-IR) spectroscopies. Cu(II) - ligands complexation at different Cu(II)/ligand molar ratios was studied by means of UV-Vis, fluorescence and electron paramagnetic resonance (EPR) spectroscopies. The results indicate the formation of Cu-N4 and Cu-N2O2 coordinations with different structure and stability conditions for the L1 and L2 derivatives. A different solvent at different polarity also affects the structural properties and the range of stability. L1 provided more stable Cu-N4 complexes than L2. [Cu(L1) (NO3)2] also showed stronger antibacterial and antifungal abilities than those of [Cu(L2) (NO3)2]. These results indicate that [Cu(L1) (NO3)2] works as antimicrobial agent to be used in biomedical and agrochemical applications.

  10. High-sensitivity determination of Zn(II) and Cu(II) in vitro by fluorescence polarization

    NASA Astrophysics Data System (ADS)

    Thompson, Richard B.; Maliwal, Badri P.; Feliccia, Vincent; Fierke, Carol A.

    1998-04-01

    Recent work has suggested that free Cu(II) may play a role in syndromes such as Crohn's and Wilson's diseases, as well as being a pollutant toxic at low levels to shellfish and sheep. Similarly, Zn(II) has been implicated in some neural damage in the brain resulting from epilepsy and ischemia. Several high sensitivity methods exist for determining these ions in solution, including GFAAS, ICP-MS, ICP-ES, and electrochemical techniques. However, these techniques are generally slow and costly, require pretreatment of the sample, require complex instruments and skilled personnel, and are incapable of imaging at the cellular and subcellular level. To address these shortcomings we developed fluorescence polarization (anisotropy) biosensing methods for these ions which are very sensitivity, highly selective, require simple instrumentation and little pretreatment, and are inexpensive. Thus free Cu(II) or Zn(II) can be determined at picomolar levels by changes in fluorescence polarization, lifetime, or wavelength ratio using these methods; these techniques may be adapted to microscopy.

  11. Pecan nutshell as biosorbent to remove Cu(II), Mn(II) and Pb(II) from aqueous solutions.

    PubMed

    Vaghetti, Julio C P; Lima, Eder C; Royer, Betina; da Cunha, Bruna M; Cardoso, Natali F; Brasil, Jorge L; Dias, Silvio L P

    2009-02-15

    In the present study we reported for the first time the feasibility of pecan nutshell (PNS, Carya illinoensis) as an alternative biosorbent to remove Cu(II), Mn(II) and Pb(II) metallic ions from aqueous solutions. The ability of PNS to remove the metallic ions was investigated by using batch biosorption procedure. The effects such as, pH, biosorbent dosage on the adsorption capacities of PNS were studied. Four kinetic models were tested, being the adsorption kinetics better fitted to fractionary-order kinetic model. Besides that, the kinetic data were also fitted to intra-particle diffusion model, presenting three linear regions, indicating that the kinetics of adsorption should follow multiple sorption rates. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. Taking into account a statistical error function, the data were best fitted to Sips isotherm model. The maximum biosorption capacities of PNS were 1.35, 1.78 and 0.946mmolg(-1) for Cu(II), Mn(II) and Pb(II), respectively.

  12. Chelation of Cu(II), Zn(II), and Fe(II) by tannin constituents of selected edible nuts.

    PubMed

    Karamać, Magdalena

    2009-12-22

    The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II). The Fe(II) complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II) by approximately 90%. The capacity to chelate Zn(II) was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II), whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II) chelation took place at the levels tested.

  13. Synthesis, interaction with DNA and antiproliferative activities of two novel Cu(II) complexes with norcantharidin and benzimidazole derivatives.

    PubMed

    Song, Wen-Ji; Lin, Qiu-Yue; Jiang, Wen-Jiao; Du, Fang-Yuan; Qi, Qing-Yuan; Wei, Qiong

    2015-02-25

    Two novel complexes [Cu(L)2(Ac)2]·3H2O (1) (L=N-2-methyl benzimidazole demethylcantharate imide, C16H15N3O3, Ac=acetate, C2H3O2) and [Cu(bimz)2(DCA)] (2) (bimz=benzimidazole, C7H6N2; DCA=demethylcantharate, C8H8O5) were synthesized and characterized by elemental analysis, infrared spectra and X-ray diffraction techniques. Cu(II) ion was four-coordinated in complex 1, Cu(II) ion was five-coordinated in complex 2. A large amount of intermolecular hydrogen-bonding and π-π stacking interactions were observed in these complex structures. The DNA-binding properties of these complexes were investigated using electronic absorption spectra, fluorescence spectra, viscosity measurements and agarose gel electrophoresis. The interactions between the complexes and bovine serum albumin (BSA) were investigated by fluorescence spectra. The antiproliferative activities of the complexes against human hepatoma cells (SMMC7721) were tested in vitro. And the results showed that these complexes could bind to DNA in moderate intensity via partial intercalation, and complexes 1 and 2 could cleave plasmid DNA through hydroxyl radical mechanism. Title complexes could effectively quench the fluorescence of BSA through static quenching. Meanwhile, title complexes had stronger antiproliferative effect compared to L and Na2(DCA) within the tested concentration range. And complex 1 possessed more antiproliferative active than complex 2.

  14. Effect of the Amine Concentration on Phase Evolution and Densification in Printed Films Using Cu(II) Complex Ink.

    PubMed

    Choi, Yun-Hyuk; Hong, Seong-Hyeon

    2015-07-28

    The nucleation and growth behavior of Cu nanoparticles during thermal heating of Cu(II) complex inks for printed Cu metallization were investigated, particularly focusing on the effects of the amine concentration on the microstructure evolution and electrical conductivity. Herein, the dual effects of hexylamine as a reducing agent dissociating the carboxyl group from the precursor and a capping agent hindering the subsequent growth of Cu nuclei were confirmed. On the basis of such dual effects of amine, the sufficient complexation of the Cu(II) precursor with a high amine concentration in the ink led to the single-route growth of Cu nanoparticles during thermal heating, which resulted in the dense film with a narrow particle size distribution exhibiting a high electrical conductivity. The electrical conductivity of the film could be further enhanced by a reducing atmosphere with formic acid. Significantly, the understanding of the ink chemistry and the nucleation and growth kinetics in the metal ion complex or metal-organic decomposition (MOD) ink can provide the design rules for the formulation of the solution-type inks to control the microstructure of printed metallization.

  15. Relative Orientation of Imidazole Ligands in Cu(II) Model and Abeta peptides Complexes revealed by ESEEM Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hernandez, Jessica; Sun, Li; Warncke, Kurt

    2009-11-01

    Alzheimer's Disease (AD) is associated with the aggregation and fibrillization of the beta-amyloid protein (Abeta). The coordination of Cu(II) by peptide histidine imidazole sidechains is proposed to play an important role in determining the fibrillization ``switch'' [1]. We have developed techniques of X-band electron spin echo envelope modulation (ESEEM) spectroscopy to determine the molecular structure of the Cu(II)-histidine imidazole coordination in cryotrapped soluble and fibrillar forms of Abeta peptides, in order to gain insight into the factors that govern fibrillization. Focusing on the ESEEM double quantum harmonic feature, we use our hybrid optimization-based OPTESIM simulation software [2] to determine the mutual orientation of the imidazole rings in Cu(II)--bis-imidazole complexes that include cis- versus trans- coordination. The technique has been applied to Abeta(13-21) peptide to reveal the Cu(II) coordination mode in fibrils. [1] Dong , J., et al., Proc. Natl. Acad. Sci., 2007, 104, 13313. [2] Sun, L., et al., J. Magn. Reson. 2009, 200, 21

  16. Synthesis, structural studies and biological activity of new Cu(II) complexes with acetyl derivatives of 7-hydroxy-4-methylcoumarin.

    PubMed

    Klepka, Marcin T; Drzewiecka-Antonik, Aleksandra; Wolska, Anna; Rejmak, Paweł; Ostrowska, Kinga; Hejchman, Elżbieta; Kruszewska, Hanna; Czajkowska, Agnieszka; Młynarczuk-Biały, Izabela; Ferenc, Wiesława

    2015-04-01

    The new Cu(II) complexes with 6-acetyl-7-hydroxy-4-methylcoumarin (HL1) and 8-acetyl-7-hydroxy-4-methylcoumarin (HL2) have been obtained by the electrochemical method. The density functional theory calculations and X-ray absorption spectroscopy techniques have been used to geometrically describe a series of new compounds. The studies have been focused on the coordination mode of the hydroxy ligands to the metallic centre. The complexes, Cu(HL1)2 and Cu(HL2)2⋅0.5H2O, have flat square geometry with oxygen atoms in the first coordination sphere. Two bidentate anionic coumarins are bonded to the metal cation via the acetyl and deprotonated hydroxyl O atoms. Biological activity, including microbiological and cytotoxic, has been evaluated and found to be enhanced in comparison with the parent ligands. Moreover, the Cu(II) complex with 8-acetyl-7-hydroxy-4-methylcoumarin shows similar antifungal activity as commercially used fluconazole.

  17. An unlikely DNA cleaving agent: A photo-active trinuclear Cu(II) complex based on hexaazatriphenylene.

    PubMed

    Williams, Dominique E; Fischer, Christina M; Kassai, Miki; Gude, Lourdes; Fernández, María-José; Lorente, Antonio; Grant, Kathryn B

    2017-03-01

    This paper describes the synthesis of a trinuclear Cu(II) complex (4) containing a central 1,4,5,8,9,12-hexaazatriphenylene-hexacarboxylate (hat) core (3). Low, micromolar concentrations of the negatively charged parent ligand 3 and the neutral trinuclear complex 4 were found to photocleave negatively charged pUC19 plasmid DNA with high efficiency at neutral pH (350nm, 50min, 22°C). The interactions of complex 4 with double-helical DNA were studied in detail. Scavenger and colorimetric assays pointed to the formation of Cu(I), superoxide anion radicals, hydrogen peroxide, and hydroxyl radicals during photocleavage reactions. UV-visible absorption, circular dichroism, DNA thermal denaturation, and fluorescence data suggested that the Cu(II) complex contacts double-stranded DNA in an external fashion. The persistent association of ligand 3 and complex 4 with Na(I) and/or other cations in aqueous solution might facilitate electrostatic DNA interactions.

  18. New Mononuclear Cu(II) Complexes and 1D Chains with 4-Amino-4H-1,2,4-triazole

    PubMed Central

    Dîrtu, Marinela M.; Boland, Yves; Gillard, Damien; Tinant, Bernard; Robeyns, Koen; Safin, Damir A.; Devlin, Eamonn; Sanakis, Yiannis; Garcia, Yann

    2013-01-01

    The crystal structures of two mononuclear Cu(II) NH2trz complexes [Cu(NH2trz)4(H2O)](AsF6)2 (I) and [Cu(NH2trz)4(H2O)](PF6)2 (II) as well as two coordination polymers [Cu(μ2-NH2trz)2Cl]Cl·H2O (III) and [Cu(μ2-NH2trz)2Cl] (SiF6)0.5·1.5H2O (IV) are presented. Cationic 1D chains with bridging bis-monodentate μ2-coordinated NH2trz and bridging μ2-coordinated chloride ligands are present in III and IV. In these coordination polymers, the Cu(II) ions are strongly antiferromagnetically coupled with J = −128.4 cm−1 for III and J = −143 cm−1 for IV (H = −J∑SiSi+1), due to the nature of the bridges between spin centers. Inter-chain interactions present in the crystal structures were taken into consideration, as well as g factors, which were determined experimentally, for the quantitative modeling of their magnetic properties. PMID:24300095

  19. Kinetics modelling of Cu(II) biosorption on to coconut shell and Moringa oleifera seeds from tropical regions.

    PubMed

    Acheampong, Mike A; Pereira, Joana P C; Meulepas, Roel J W; Lens, Piet N L

    2012-01-01

    Adsorption kinetic studies are of great significance in evaluating the performance of a given adsorbent and gaining insight into the underlying mechanism. This work investigated the sorption kinetics of Cu(II) on to coconut shell and Moringa oleifera seeds using batch techniques. To understand the mechanisms of the biosorption process and the potential rate-controlling steps, kinetic models were used to fit the experimental data. The results indicate that kinetic data were best described by the pseudo-second-order model with correlation coefficients (R2) of 0.9974 and 0.9958 for the coconut shell and Moringa oleifera seeds, respectively. The initial sorption rates obtained for coconut shell and Moringa oleifera seeds were 9.6395 x 10(-3) and 8.3292 x 10(-2) mg g(-1) min(-1), respectively. The values of the mass transfer coefficients obtained for coconut shell (1.2106 x 10(-3) cm s(-1)) and Moringa oleifera seeds (8.965 x 10(-4) cm s(-1)) indicate that the transport of Cu(II) from the bulk liquid to the solid phase was quite fast for both materials investigated. The results indicate that intraparticle diffusion controls the rate of sorption in this study; however, film diffusion cannot be neglected, especially at the initial stage of sorption.

  20. A new porous magnetic chitosan modified by melamine for fast and efficient adsorption of Cu(II) ions.

    PubMed

    Wu, Zhan-Chao; Wang, Zhao-Zhan; Liu, Jie; Yin, Jin-Hua; Kuang, Shao-Ping

    2015-11-01

    A new porous magnetic chitosan modified by melamine (MA-CS/Fe3O4) was synthesized. The compositions and surface topographies were characterized by infrared (IR) spectroscopy, X-ray diffraction (XRD) analysis, thermogravimetric (TG) analysis and scanning electron microscope (SEM), respectively. The results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation (R>0.999). The adsorption isotherm was well fitted by the Langmuir equation (R>0.999), and the values of separation factors were in the range of 0-1.0. The maximum adsorption capacity for Cu(II) was 2.58mmolg(-1) at the optimal experimental conditions, which were pH=5.5, t=25min, C0=5.0mmolL(-1). The rate-controlling step was supposed to be chemical adsorption rather than mass transport. The adsorbent still exhibited high adsorption capacity after five regeneration cycles. The adsorption mechanism was due to coordination between Cu(II) and N atoms.

  1. Synthesis, interaction with DNA and antiproliferative activities of two novel Cu(II) complexes with norcantharidin and benzimidazole derivatives

    NASA Astrophysics Data System (ADS)

    Song, Wen-Ji; Lin, Qiu-Yue; Jiang, Wen-Jiao; Du, Fang-Yuan; Qi, Qing-Yuan; Wei, Qiong

    2015-02-01

    Two novel complexes [Cu(L)2(Ac)2]·3H2O (1) (L = N-2-methyl benzimidazole demethylcantharate imide, C16H15N3O3, Ac = acetate, C2H3O2) and [Cu(bimz)2(DCA)] (2) (bimz = benzimidazole, C7H6N2; DCA = demethylcantharate, C8H8O5) were synthesized and characterized by elemental analysis, infrared spectra and X-ray diffraction techniques. Cu(II) ion was four-coordinated in complex 1, Cu(II) ion was five-coordinated in complex 2. A large amount of intermolecular hydrogen-bonding and π-π stacking interactions were observed in these complex structures. The DNA-binding properties of these complexes were investigated using electronic absorption spectra, fluorescence spectra, viscosity measurements and agarose gel electrophoresis. The interactions between the complexes and bovine serum albumin (BSA) were investigated by fluorescence spectra. The antiproliferative activities of the complexes against human hepatoma cells (SMMC7721) were tested in vitro. And the results showed that these complexes could bind to DNA in moderate intensity via partial intercalation, and complexes 1 and 2 could cleave plasmid DNA through hydroxyl radical mechanism. Title complexes could effectively quench the fluorescence of BSA through static quenching. Meanwhile, title complexes had stronger antiproliferative effect compared to L and Na2(DCA) within the tested concentration range. And complex 1 possessed more antiproliferative active than complex 2.

  2. Electrical conducting bis(oxalato)platinate complex with direct connection of CuII ions.

    PubMed

    Yamamoto, Chihiro; Nishikawa, Hiroyuki; Nihei, Masayuki; Shiga, Takuya; Hedo, Masato; Uwatoko, Yoshiya; Sawa, Hiroshi; Kitagawa, Hiroshi; Taguchi, Yasujiro; Iwasa, Yoshihiro; Oshio, Hiroki

    2006-12-11

    Reactions of K1.62[Pt(ox)2].2H2O and [Cu(bpy)(H2O)3](NO3)2 yielded partially oxidized one-dimensional (1D) bis(oxalato)platinates of [Cu(bpy)(H2O)n]6[Pt(ox)2]7.7H2O (n = 2, 3, or 4) (1) and [Cu(bpy)(H2O)n]8[Pt(ox)2]10.8H2O (n = 3 or 4) (2). The average oxidation numbers of the platinum ions in 1 and 2 are +2.29 and +2.40, respectively. Complexes 1 and 2 crystallize in the triclinic P and monoclinic C2/c space groups, respectively, and the [Pt(ox)2]n- anions are stacked along the crystallographic b axis with 7-fold periodicity for 1 and 10-fold periodicity for 2. In 1, an oxalato ligand in the platinum chain directly coordinates to a paramagnetic [Cu(bpy)(H2O)3]2+ ion, whereas no such direct coordination was observed for 2. The electrical conductivity of 2 at room temperature along the platinum chain is approximately 3 orders of magnitude smaller (sigma||= 1.3 x 10(-3) S cm(-1)) than that of 1 (sigma|| = 0.9-0.5 S cm(-1)), and the activation energies of 1 and 2 are 29 and 67 meV, respectively. The longest inter-platinum distances in 1 and 2 are 2.762 and 3.0082 A, respectively, and this is responsible for the lower electrical conductivity of 2. An X-ray oscillation photograph taken along the b axis of 1 reveals the 7-fold periodicity in the 1D chain, consistent with the period of the Peierls distortion estimated from the degree of partial oxidation. The semiconducting state of 1 can therefore be regarded as a commensurate Peierls state. The magnetoresistance of 1 at ambient pressure indicates no interaction between conduction electrons in the platinum chain and local spins of the paramagnetic CuII ions. Application of hydrostatic pressures of up to 3 GPa enhances electrical conduction, as is often seen as the usual pressure effect on the electrical conductivity, which is due to enhanced orbital (Pt-5dz2) overlap by pressure application.

  3. Synthesis, characterization, and stereochemistry of S-bridged Co(III)MCo(III)(M = Pd(II), Pt(II)) trinuclear complexes containing two non-bridging thiolato groups: building blocks for the construction of chiral heterometallic aggregates.

    PubMed

    Chikamoto, Yu; Hirotsu, Masakazu; Yamaguchi, Tadashi; Yoshimura, Takashi; Konno, Takumi

    2004-11-07

    The reaction of fac(S)-[Co(aet)(3)](aet = aminoethanethiolate) with [PdCl(4)](2-) in a 2:1 ratio in water gave an S-bridged Co(III)Pd(II)Co(III) trinuclear complex composed of two mer(S)-[Co(aet)(3)] units, [Pd[Co(aet)(3)](2)](2+)([1](2+)). In [1](2+), each of the two mer(S)-[Co(aet)(3)] units is bound to a square-planar Pd(II) ion through two of three thiolato groups, leaving two non-bridging thiolato groups at the terminal. Of two geometrical forms, syn and anti, possible for [Pd[Co(aet)(3)](2)](2+), which arise from the difference in arrangement of two terminal non-bridging thiolato groups, [1](2+) afforded only the syn form. A similar reaction of fac(S)-[Co(aet)(3)] with [PtCl(4)](2-) or trans-[PtCl(2)(NH(3))(2)] produced an analogous Co(III)Pt(II)Co(III) trinuclear complex, [Pt[Co(aet)(3)](2)](2+)([2](2+)), but both the syn and anti forms were formed for [2](2+). Complexes [1](2+) and syn- and anti-[2](2+), which exclusively exist as a racemic(DeltaDelta/LambdaLambda) form, were successfully optically resolved with use of [Sb(2)(R,R-tartrato)(2)](2-) as the resolving agent. The reaction of syn-[2](2+) with [AuCl[S(CH(2)CH(2)OH)(2)

  4. The exocyclic amino group of adenine in Pt(II) and Pd(II) complexes: a critical comparison of the X-ray crystallographic structural data and gas phase calculations.

    PubMed

    Silaghi-Dumitrescu, Radu; Mihály, Béla; Mihály, Timea; Attia, Amr A A; Sanz Miguel, Pablo J; Lippert, Bernhard

    2017-03-17

    A detailed computational (DFT level of theory) study regarding the nature of the exocyclic amino group, N6H2, of the model nucleobase 9-methyladenine (9MeA) and its protonated (9MeAH(+)) and deprotonated forms (9MeA-H), free and metal-complexed, has been conducted. The metals are Pt(II) and Pd(II), bonded to nitrogen-containing co-ligands (NH3, dien, bpy), with N1, N6, and N7 being the metal-binding sites, individually or in different combinations. The results obtained from gas phase calculations are critically compared with X-ray crystallography data, whenever possible. In the majority of cases, there is good qualitative agreement between calculated and experimentally determined C6-N6 bond lengths, but calculated values always show a trend to larger values, by 0.02-0.08 Å. Both methods indicate, with few exceptions, a high degree of double-bond character of C6-N6, consistent with an essentially sp(2)-hybridized N6 atom. The shortest values for C6-N6 distances in X-ray crystal structures are around 1.30 Å. Exceptions refer to cases in which DFT calculations suggest the existence of a hydrogen bond with N6H2 acting as a H bond acceptor, hence a situation with N6 having undergone a substantial hybridization shift toward sp(3). Nevertheless, even in these cases the C6-N6 bond (1.392 Å) is still halfway between a typical C-N single bond (1.48 Å) and a typical C=N double bond (1.28 Å). This scenario is, however, not borne out by X-ray crystallographic results, and is attributed to the absence of counter anions and solvent molecules in the calculated structures.

  5. Enneanuclear [Ni6Ln3] Cages: [Ln(III)3] Triangles Capping [Ni(II)6] Trigonal Prisms Including a [Ni6Dy3] Single-Molecule Magnet.

    PubMed

    Canaj, Angelos B; Tzimopoulos, Demetrios I; Siczek, Milosz; Lis, Tadeusz; Inglis, Ross; Milios, Constantinos J

    2015-07-20

    The use of (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) ligand, H3L, in Ni/Ln chemistry has led to the isolation of three new isostructural [Ni(II)6Ln(III)3] metallic cages. More specifically, the reaction of Ni(ClO4)2·6H2O, the corresponding lanthanide nitrate salt, and H3L in MeCN, under solvothermal conditions in the presence of NEt3, led to the isolation of three complexes with the formulas [Ni6Gd3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (1·5.75MeCN·2Et2O·1.5H2O), [Ni6Dy3(OH)6(HL)6(NO3)3]·2MeCN·2.7Et2O·2.4H2O (2·2MeCN·2.7Et2O·2.4H2O), and [Ni6Er3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (3·5.75MeCN·2Et2O·1.5H2O). The structure of all three clusters describes a [Ln(III)3] triangle capping a [Ni(II)6] trigonal prism. Direct current magnetic susceptibility studies in the 5-300 K range for complexes 1-3 reveal the different nature of the magnetic interactions within the clusters: dominant antiferromagnetic exchange interactions for the Dy(III) and Er(III) analogues and dominant ferromagnetic interactions for the Gd(III) example. Alternating current magnetic susceptibility measurements under zero external dc field displayed fully formed temperature- and frequency-dependent out-of-phase peaks for the [Ni(II)6Dy(III)3] analogue, establishing its single molecule magnetism behavior with Ueff = 24 K.

  6. Optimization of conditions for Cu(II) adsorption on D151 resin from aqueous solutions using response surface methodology and its mechanism study.

    PubMed

    Zhang, Hao; Xiong, Chunhua; Liu, Fang; Zheng, Xuming; Jiang, Jianxiong; Zheng, Qunxiong; Yao, Caiping

    2014-01-01

    An experimental study on the removal of Cu(II) from aqueous solutions by D151 resin was carried out in a batch system. The response surface methodology (RSM)-guided optimization indicated that the optimal adsorption conditions are: temperature of 35 °C, pH of 5.38, and initial Cu(II) concentration of 0.36 mg/mL, and the predicted adsorption capacity from the model reached 328.3 mg/g. At optimum adsorption conditions, the adsorption capacity of Cu(II) was 321.6 mg/g, which obtained from real experiments what were in close agreement with the predicted value. The adsorption isotherms data fitted the Langmuir model well, and the correlation coefficient has been evaluated. The calculation data of thermodynamic parameters (ΔG, ΔS, and ΔH) confirmed that the adsorption process was endothermic and spontaneous in nature. The desorption study revealed that Cu(II) can be effectively eluted by 1 mol/l HCl solution, and the recovery was 100%. Moreover, the characterization was undertaken by infrared (IR) spectroscopy.

  7. DNA binding, photoactivated DNA cleavage and cytotoxic activity of Cu(II) and Co(II) based Schiff-base azo photosensitizers

    NASA Astrophysics Data System (ADS)

    Pradeepa, S. M.; Bhojya Naik, H. S.; Vinay Kumar, B.; Indira Priyadarsini, K.; Barik, Atanu; Prabhakara, M. C.

    2015-04-01

    A new class of Cu(II) and Co(II) complexes of azo-containing Schiff base of the type [Cu(L1)2] and [Co(L1)2], where L1 = 4-[(E)-{2-hydroxy-3-[(E)-(4-bromophenyl)diazenyl]benzylidene}amino]benzoic acid have been synthesized and characterized. Extension of conjugation and the presence of free carboxylic acid group of the ligand L1 increased the wavelength of the complexes from visible region to the near IR region (620-850 nm). The Cu(II) and Co(II) complexes interacted with CT-DNA via intercalative mode with the respective Kb value of 3.2 × 104 M-1 and 2.9 × 104 M-1 and acted as proficient photocleavers of SC pUC19 DNA in UV-A light, forming 1O2 as the reactive oxygen species with the quantum yield of 0.38 and 0.36, respectively. Furthermore, the Cu(II) and Co(II) complexes showed photocytotoxicity toward two selected tumor cell lines MCF-7 and A549 by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) method, and the Cu(II) complex exhibits higher photocytotoxicity than Co(II) complex against each of the selected cell lines, this result is identical with their DNA binding ability order.

  8. DNA binding, photoactivated DNA cleavage and cytotoxic activity of Cu(II) and Co(II) based Schiff-base azo photosensitizers.

    PubMed

    Pradeepa, S M; Bhojya Naik, H S; Vinay Kumar, B; Indira Priyadarsini, K; Barik, Atanu; Prabhakara, M C

    2015-04-15

    A new class of Cu(II) and Co(II) complexes of azo-containing Schiff base of the type [Cu(L1)2] and [Co(L1)2], where L1=4-[(E)-{2-hydroxy-3-[(E)-(4-bromophenyl)diazenyl]benzylidene}amino]benzoic acid have been synthesized and characterized. Extension of conjugation and the presence of free carboxylic acid group of the ligand L1 increased the wavelength of the complexes from visible region to the near IR region (620-850 nm). The Cu(II) and Co(II) complexes interacted with CT-DNA via intercalative mode with the respective Kb value of 3.2×10(4) M(-1) and 2.9×10(4) M(-1) and acted as proficient photocleavers of SC pUC19 DNA in UV-A light, forming (1)O2 as the reactive oxygen species with the quantum yield of 0.38 and 0.36, respectively. Furthermore, the Cu(II) and Co(II) complexes showed photocytotoxicity toward two selected tumor cell lines MCF-7 and A549 by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) method, and the Cu(II) complex exhibits higher photocytotoxicity than Co(II) complex against each of the selected cell lines, this result is identical with their DNA binding ability order.

  9. Biosorption characteristics of Aspergillus flavus biomass for removal of Pb(II) and Cu(II) ions from an aqueous solution.

    PubMed

    Akar, Tamer; Tunali, Sibel

    2006-10-01

    The Pb(II) and Cu(II) biosorption characteristics of Aspergillus flavus fungal biomass were examined as a function of initial pH, contact time and initial metal ion concentration. Heat inactivated (killed) biomass was used in the determination of optimum conditions before investigating the performance of pretreated biosorbent. The maximum biosorption values were found to be 13.46 +/- 0.99 mg/g for Pb(II) and 10.82 +/- 1.46 mg/g for Cu(II) at pH 5.0 +/- 0.1 with an equilibrium time of 2 h. Detergent, sodium hydroxide and dimethyl sulfoxide pretreatments enhanced the biosorption capacity of biomass in comparison with the heat inactivated biomass. The biosorption data obtained under the optimum conditions were well described by the Freundlich isotherm model. Competitive biosorption of Pb(II) and Cu(II) ions was also investigated to determine the selectivity of the biomass. The results indicated that A. flavus is a suitable biosorbent for the removal of Pb(II) and Cu(II) ions from aqueous solution.

  10. Functionalized cotton via surface-initiated atom transfer radical polymerization for enhanced sorption of Cu(II) and Pb(II).

    PubMed

    Zheng, Y Q; Deng, Shubo; Niu, Li; Xu, F J; Chai, M Y; Yu, Gang

    2011-09-15

    The surface-initiated atom transfer radical polymerization (ATRP) was used to successfully prepare the aminated cotton and polyacrylic acid sodium (P(AA-Na))-grafted cotton for the efficient removal of Cu(II) and Pb(II) from aqueous solution in this study. The modified cotton surfaces were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The grafted long polymers with high density of amine and carboxyl groups on the cotton surfaces were responsible for the enhanced adsorption of heavy metals. The sorption behaviors including sorption kinetics, isotherms and pH effect were investigated. The sorption equilibrium of Cu(II) and Pb(II) was achieved within 1h on the P(AA-Na)-grafted cotton, much faster than 8h on the aminated cotton. According to the Langmuir fitting, the maximum sorption capacities of Cu(II) and Pb(II) on the P(AA-Na)-grafted cotton were 2.45 and 2.44 mmol/g, respectively, higher than many adsorbents reported in the literature. The P(AA-Na)-grafted cotton had better adsorption behaviors for Cu(II) and Pb(II) than the aminated cotton.

  11. Sub-micron-sized polyethylenimine-modified polystyrene/Fe3O4/chitosan magnetic composites for the efficient and recyclable adsorption of Cu(II) ions

    NASA Astrophysics Data System (ADS)

    Xiao, Changwei; Liu, Xijian; Mao, Shimin; Zhang, Lijuan; Lu, Jie

    2017-02-01

    A sub-micron-sized polyethylenimine(PEI)-modified polystyrene/Fe3O4/chitosan magnetic composite (PS/Fe3O4/CS-PEI) was developed as a novel adsorbent for the removal of Cu(II) ions from aqueous solutions. The PS/Fe3O4/CS-PEI microspheres with a diameter of ∼300 nm can be highly monodisperse and conveniently separated from suspensions by a magnet due to their excellent magnetism. When the PS/Fe3O4/CS-PEI microspheres were used as an absorbent for the absorption of Cu(II) ions, the adsorption isotherms and adsorption kinetics well fitted the Langmuir model and the pseudo-second-order model, respectively. The maximum adsorption capacity was about 204.6 mg g-1, which was higher than those of other chitosan adsorbents reported recently. The adsorption was considerably fast, reaching the equilibrium within 15 min. In addition, the adsorbed Cu(II) ions could be effectively desorbed using 0.1 mol L-1 NaOH solution, and the regeneration study proved that the composite microspheres could be repeatedly utilized without significant capacity loss after six cycles. All the results demonstrated that the synthesized sub-micron-sized magnetic PS/Fe3O4/CS-PEI composites can be used as an ideal adsorbent of Cu(II) ions for environmental cleanup applications.

  12. Magnetic-epichlorohydrin crosslinked chitosan schiff's base (m-ECCSB) as a novel adsorbent for the removal of Cu(II) ions from aqueous environment.

    PubMed

    Gutha, Yuvaraja; Zhang, Yaping; Zhang, Weijiang; Jiao, Xu

    2017-04-01

    Metal ions cause a serious public health problem. It is a great challenge to find an effective and efficient adsorbent to remove heavy metals from wastewater. Chitosan-based adsorbents are potential and effective for heavy metal ion removal. Hence a novel m-ECCSB was synthesized, characterized and utilized as an adsorbent for the removal of Cu(II) ions from aqueous solution. Various factors affecting the uptake behavior such as pH, adsorbent dosage, contact time, initial concentration of Cu(II) and temperature effect were investigated. Maximum adsorption capability (123.10mg/g) was obtained at pH=6, adsorbent dose of=250mg, rotational speed=200rpm, contact time=60min, and temperature of 323K. The result of the kinetic study shows that the adsorption of Cu(II) could be described by the pseudo-second-order equation. Equilibrium data were analysed with the Langmuir, Freundlich and Dubinin-Radushkevich isotherms and Langmuir model was found to provide the best fit of the experimental data. The thermodynamic parameters showed that the adsorption of Cu(II) onto m-ECCSB was spontaneous (ΔG°=-8.990, -10.00 and -10.593kJ/mol), endothermic (ΔH°=15.674, 15.478 and 15.699kJ/mol) and ΔS° (0.0814J/molK) suggests an increased randomness at the solid/solution interface under the studied conditions.

  13. Adsorption and desorption of Cu(II), Cd(II) and Pb(II) ions using chitosan crosslinked with epichlorohydrin-triphosphate as the adsorbent.

    PubMed

    Laus, Rogério; Costa, Thiago G; Szpoganicz, Bruno; Fávere, Valfredo T

    2010-11-15

    In this study, chitosan (CTS) was crosslinked with both epichlorohydrin (ECH) and triphosphate (TPP), by covalent and ionic crosslinking, respectively. The resulting new CTS-ECH-TPP adsorbent was characterized by CHN analysis, EDS, FTIR spectroscopy, TGA and DSC, and the adsorption and desorption of Cu(II), Cd(II) and Pb(II) ions in aqueous solution were investigated. Potentiometric studies were also performed and revealed three titratable protons for each pK(a) value of 5.14, 6.76 and 9.08. The results obtained showed that the optimum pH values for adsorption were 6.0 for Cu(II), 7.0 for Cd(II) and 5.0 for Pb(II). The kinetics study demonstrated that the adsorption process proceeded according to the pseudo-second-order model. Three isotherm models (Langmuir, Freundlich and Dubinin-Radushkevich) were employed in the analysis of the adsorption equilibrium data. The Langmuir model resulted in the best fit and the new adsorbent had maximum adsorption capacities for Cu(II), Cd(II) and Pb(II) ions of 130.72, 83.75 and 166.94 mg g(-1), respectively. Desorption studies revealed that HNO(3) and HCl were the best eluents for desorption of Cu(II), Cd(II) and Pb(II) ions from the crosslinked chitosan.

  14. Successive extraction of As(V), Cu(II) and P(V) ions from water using spent coffee powder as renewable bioadsorbents

    PubMed Central

    Hao, Linlin; Wang, Peng; Valiyaveettil, Suresh

    2017-01-01

    For the first time, renewable and easy accessible pre-bleached spent coffee powder coated with polyethylenimine (PEI) and ferric ions (Coffee-PEI-Fe) was used for the successive adsorption of As(V), Cu(II) and P(V) ions from spiked water samples. Fully characterized coffee-PEI-Fe was employed for batch mode experiments. Kinetic regression analysis showed that the adsorption processes of As(V) and P(V) anions follows a pseudo-second-order model, while the adsorption of Cu(II) ions fit with a pseudo-first-order model. The maximum adsorption capacities estimated by Langmuir model for As(V), Cu(II) and P(V) ions were 83.3, 200.1, and 50.2 mg/g, respectively. The simulated results revealed that the internal diffusion is the rate-determining step for the adsorptions of As(V) and Cu(II) ions, while film diffusion is the mass transfer resistance for the adsorption of P(V) ions on the surface of coffee-PEI-Fe. The successive adsorptions of adsorbates were achieved through electrostatic attraction between adsorbent surface and adsorbates. The dynamic column adsorption behavior of the adsorbent was described by Thomas model, which showed a good agreement with the experimental values (qexp). The results presented in this paper could be used for developing efficient adsorbent from renewable materials for water purification. PMID:28220853

  15. Successive extraction of As(V), Cu(II) and P(V) ions from water using spent coffee powder as renewable bioadsorbents

    NASA Astrophysics Data System (ADS)

    Hao, Linlin; Wang, Peng; Valiyaveettil, Suresh

    2017-02-01

    For the first time, renewable and easy accessible pre-bleached spent coffee powder coated with polyethylenimine (PEI) and ferric ions (Coffee-PEI-Fe) was used for the successive adsorption of As(V), Cu(II) and P(V) ions from spiked water samples. Fully characterized coffee-PEI-Fe was employed for batch mode experiments. Kinetic regression analysis showed that the adsorption processes of As(V) and P(V) anions follows a pseudo-second-order model, while the adsorption of Cu(II) ions fit with a pseudo-first-order model. The maximum adsorption capacities estimated by Langmuir model for As(V), Cu(II) and P(V) ions were 83.3, 200.1, and 50.2 mg/g, respectively. The simulated results revealed that the internal diffusion is the rate-determining step for the adsorptions of As(V) and Cu(II) ions, while film diffusion is the mass transfer resistance for the adsorption of P(V) ions on the surface of coffee-PEI-Fe. The successive adsorptions of adsorbates were achieved through electrostatic attraction between adsorbent surface and adsorbates. The dynamic column adsorption behavior of the adsorbent was described by Thomas model, which showed a good agreement with the experimental values (qexp). The results presented in this paper could be used for developing efficient adsorbent from renewable materials for water purification.

  16. Successive extraction of As(V), Cu(II) and P(V) ions from water using spent coffee powder as renewable bioadsorbents.

    PubMed

    Hao, Linlin; Wang, Peng; Valiyaveettil, Suresh

    2017-02-21

    For the first time, renewable and easy accessible pre-bleached spent coffee powder coated with polyethylenimine (PEI) and ferric ions (Coffee-PEI-Fe) was used for the successive adsorption of As(V), Cu(II) and P(V) ions from spiked water samples. Fully characterized coffee-PEI-Fe was employed for batch mode experiments. Kinetic regression analysis showed that the adsorption processes of As(V) and P(V) anions follows a pseudo-second-order model, while the adsorption of Cu(II) ions fit with a pseudo-first-order model. The maximum adsorption capacities estimated by Langmuir model for As(V), Cu(II) and P(V) ions were 83.3, 200.1, and 50.2 mg/g, respectively. The simulated results revealed that the internal diffusion is the rate-determining step for the adsorptions of As(V) and Cu(II) ions, while film diffusion is the mass transfer resistance for the adsorption of P(V) ions on the surface of coffee-PEI-Fe. The successive adsorptions of adsorbates were achieved through electrostatic attraction between adsorbent surface and adsorbates. The dynamic column adsorption behavior of the adsorbent was described by Thomas model, which showed a good agreement with the experimental values (qexp). The results presented in this paper could be used for developing efficient adsorbent from renewable materials for water purification.

  17. An Analytical Chemistry Experiment in Simultaneous Spectrophotometric Determination of Fe(III) and Cu(II) with Hexacyanoruthenate(II) Reagent.

    ERIC Educational Resources Information Center

    Mehra, M. C.; Rioux, J.

    1982-01-01

    Experimental procedures, typical observations, and results for the simultaneous analysis of Fe(III) and Cu(II) in a solution are discussed. The method is based on selective interaction between the two ions and potassium hexacyanoruthenate(II) in acid solution involving no preliminary sample preparations. (Author/JN)

  18. Preparation of a core-shell magnetic ion-imprinted polymer via a sol-gel process for selective extraction of Cu(II) from herbal medicines.

    PubMed

    He, Huan; Xiao, Deli; He, Jia; Li, Hui; He, Hua; Dai, Hao; Peng, Jun

    2014-05-21

    A novel magnetic surface ion-imprinted polymer (c-MMWCNTs-SiO2-IIP) was synthesized for the first time using magnetic CNTs/Fe3O4 composites (c-MMWCNTs) as the core, 3-ammonium propyltriethoxysilane (APTES) as the functional monomer, tetraethylorthosilicate (TEOS) as the cross-linker and Cu(II) as the template. c-MMWCNTs-SiO2-IIP was evaluated for selective extraction of Cu(II) from herbal medicines via a magnetic solid phase extraction (M-SPE) procedure. One factor affecting the separation and preconcentration of the target heavy metal was pH. Under the optimized experimental conditions, the adsorption kinetics and adsorption capacity of c-MMWCNTs-SiO2-IIP toward Cu(II) were estimated. The results indicated that the adsorption mechanism corresponds to a pseudo-second order adsorption process, with a correlation coefficient (R(2)) of 0.985 and a maximum adsorption capacity of 42.2 mg g(-1). The relative selectivity factor (β) values of Cu(II)/Zn(II) and Cu(II)/Pb(II) were 38.5 and 34.5, respectively. c-MMWCNTs-SiO2-IIP, combined with flame atomic absorption spectrometry, was successfully applied in the extraction and detection of Cu(II) in herbal medicine, with high recoveries ranging from 95.6% to 108.4%.

  19. Adaptively Evolving Bacterial Communities for Complete and Selective Reduction of Cr(VI), Cu(II), and Cd(II) in Biocathode Bioelectrochemical Systems.

    PubMed

    Huang, Liping; Wang, Qiang; Jiang, Linjie; Zhou, Peng; Quan, Xie; Logan, Bruce E

    2015-08-18

    Bioelectrochemical systems (BESs) have been shown to be useful in removing individual metals from solutions, but effective treatment of electroplating and mining wastewaters requires simultaneous removal of several metals in a single system. To develop multiple-reactor BESs for metals removal, biocathodes were first individually acclimated to three different metals using microbial fuel cells with Cr(VI) or Cu(II) as these metals have relatively high redox potentials, and microbial electrolysis cells for reducing Cd(II) as this metal has a more negative redox potential. The BESs were then acclimated to low concentrations of a mixture of metals, followed by more elevated concentrations. This procedure resulted in complete and selective metal reduction at rates of 1.24 ± 0.01 mg/L-h for Cr(VI), 1.07 ± 0.01 mg/L-h for Cu(II), and 0.98 ± 0.01 mg/L-h for Cd(II). These reduction rates were larger than the no adaptive controls by factors of 2.5 for Cr(VI), 2.9 for Cu(II), and 3.6 for Cd(II). This adaptive procedure produced less diverse microbial communities and changes in the microbial communities at the phylum and genus levels. These results demonstrated that bacterial communities can adaptively evolve to utilize solutions containing mixtures of metals, providing a strategy for remediating wastewaters containing Cr(VI), Cu(II), and Cd(II).

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

    NASA Astrophysics Data System (ADS)

    Sharma, Amit Kumar; Chandra, Sulekh

    2011-01-01

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

  1. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 3: Michael addition reactions and miscellaneous transformations.

    PubMed

    Aceña, José Luis; Sorochinsky, Alexander E; Soloshonok, Vadim

    2014-09-01

    The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations.

  2. Conformational change of a chiral Schiff base Ni(II) complex with a binaphthyl moiety: application of vibrational circular dichroism spectroscopy.

    PubMed

    Sato, Hisako; Mori, Yukie; Yamagishi, Akihiko

    2013-05-21

    Vibrational circular dichroism (VCD) spectroscopy was applied to study the structural change of a Ni(II) complex (denoted by [Ni(II)L]) with a chiral Schiff base ligand, (R)- or (S)-2,2'-bis(salicylideneamino)-1,1'-binaphthyl (denoted by H2L), in solution. The major signals in the mid-IR region were assigned on the basis of comparison with the DFT-calculated spectra. The complex transformed reversibly between the square-planar, tetrahedral and octahedral configurations, depending on solvents and temperature. The observed changes in the VCD peaks accompanying the transformation were analyzed in terms of the conformational change of the chiral ligand with a focus on the twisting angle in the Schiff base backbone and the dihedral angle of the binaphthyl group.

  3. Synthesis, structural characterization and DFT calculation on a square-planar Ni(II) complex of a compartmental Schiff base ligand

    NASA Astrophysics Data System (ADS)

    Biswas, Surajit; Dolai, Malay; Dutta, Arpan; Ali, Mahammad

    2016-12-01

    Reaction of a symmetric compartmental Schiff-base ligand, (H2L) with nickel(II) perchlorate hexahydrate in 1:1 M ratio in methanol gives rise to a mononuclear nickel(II) compound, NiL (1). The compound has been characterized by C, H, N microanalyses and UV-Vis spectra. The single crystal X-ray diffraction studies reveal a square planar geometry around the Ni(II) center. The compound crystallizes in monoclinic system with space group C2/c with a = 21.6425(6), b = 9.9481(3), c = 13.1958(4) Å, β = 107.728(2)°, V = 2706.16(14) Å3 and Z = 4. Ground state DFT optimization and TDDFT calculations on the ligand and complex were performed to get their UV-Vis spectral pattern.

  4. Direct C-N Coupling in an in Situ Ligand Transformation and the Self-Assembly of a Tetrametallic [Ni(II)4] Staircase.

    PubMed

    Ghosh, Aloke Kumar; Singha Mahapatra, Tufan; Clérac, Rodolphe; Mathonière, Corine; Bertolasi, Valerio; Ray, Debashis

    2015-06-01

    A [Ni(II)4] staircase complex was serendipitously prepared from the reaction of the binucleating Schiff base proligand 2,6-bis[[(3-hydroxypropyl)imino]methyl]-4-methylphenol (H3L2) and 3,5-dimethylpyrazole (Me2pzH) with nickel(II) nitrate in a reaction at room temperature, initially aimed to yield a dinuclear complex. From a room temperature metal ion/ligand reaction, the proligand H3L2 in situ transformed to modified forms HL3(2-) and HL4(2-), allowing the [Ni4] formation. Variable-temperature magnetic behavior of a [Ni4] complex reveals antiferromagnetic interactions with stabilization of a diamagnetic ground state (ST = 0).

  5. pH-dependence of the specific binding of Cu(II) and Zn(II) ions to the amyloid-{beta} peptide

    SciTech Connect

    Ghalebani, Leila; Wahlstroem, Anna; Danielsson, Jens; Waermlaender, Sebastian K.T.S.; Graeslund, Astrid

    2012-05-11

    Highlights: Black-Right-Pointing-Pointer Cu(II) and Zn(II) display pH-dependent binding to the A{beta}(1-40) peptide. Black-Right-Pointing-Pointer At pH 7.4 both metal ions display residue-specific binding to the A{beta} peptide. Black-Right-Pointing-Pointer At pH 5.5 the binding specificity is lost for Zn(II). Black-Right-Pointing-Pointer Differential Cu(II) and Zn(II) binding may help explain metal-induced AD toxicity. -- Abstract: Metal ions like Cu(II) and Zn(II) are accumulated in Alzheimer's disease amyloid plaques. The amyloid-{beta} (A{beta}) peptide involved in the disease interacts with these metal ions at neutral pH via ligands provided by the N-terminal histidines and the N-terminus. The present study uses high-resolution NMR spectroscopy to monitor the residue-specific interactions of Cu(II) and Zn(II) with {sup 15}N- and {sup 13}C,{sup 15}N-labeled A{beta}(1-40) peptides at varying pH levels. At pH 7.4 both ions bind to the specific ligands, competing with one another. At pH 5.5 Cu(II) retains its specific histidine ligands, while Zn(II) seems to lack residue-specific interactions. The low pH mimics acidosis which is linked to inflammatory processes in vivo. The results suggest that the cell toxic effects of redox active Cu(II) binding to A{beta} may be reversed by the protective activity of non-redox active Zn(II) binding to the same major binding site under non-acidic conditions. Under acidic conditions, the protective effect of Zn(II) may be decreased or changed, since Zn(II) is less able to compete with Cu(II) for the specific binding site on the A{beta} peptide under these conditions.

  6. Characterization and application of expanded graphite modified with phosphoric acid and glucose for the removal of Ni(II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Zhang, Jian; Xu, Xiaoli; Zhang, Jie; Liu, Hai; Guo, Zizhang; Kang, Yan; Li, Yiran; Xu, Jingtao

    2015-12-01

    Three kinds of modified expanded graphite (EG), impregnated with phosphoric acid (H3PO4) (P-EG), impregnated with glucose (G-EG), and impregnated with H3PO4 and glucose (G-P-EG), were prepared under a low temperature (150 °C). The adsorption capacity of G-P-EG (Qm = 7.016 mg/g) is much higher than original expanded graphite (EG Qm = 0.423 mg/g) and other two kinds of modified expanded graphite (P-EG Qm = 0.770 mg/g; G-EG Qm = 0.507 mg/g). The physicochemical properties of EG and G-P-EG were characterized by N2 adsorption/desorption, Boehm's titration and X-ray photoelectron spectroscopy (XPS). EG exhibited higher values of BET surface area (11.357 m2/g) and total pore volume (0.0303 cm3/g) than that of G-P-EG (4.808 m3/g and 0.0109 cm3/g). However, the results of Bohm's titration and XPS showed that G-P-EG contained more surface oxygen-containing functional groups. The Ni(II) adsorption equilibrium data agreed well with the Langmuir model. And the experimental data of EG and G-P-EG fitted better by pseudo-second order model. Based on the results of batch adsorption experiments and XPS analysis, there were several possible mechanisms for Ni(II) adsorption on the G-P-EG, including chemical adsorption, cation exchange, electrostatic attraction and surface complication.

  7. 4,2-Ribbon like ferromagnetic cyano-bridged Fe(III)2Ni(II) chains: a magneto-structural study.

    PubMed

    Toma, Luminita Marilena; Lescouëzec, Rodrigue; Uriel, Santiago; Llusar, Rosa; Ruiz-Pérez, Catalina; Vaissermann, Jacqueline; Lloret, Francesc; Julve, Miguel

    2007-09-07

    The low-spin iron(III) complex AsPh(4)[Fe(III)(bpy)(CN)(4)].CH(3)CN (1) [AsPh(4) = tetraphenylarsonium cation] and the heterobimetallic chains [{Fe(III)(L)(CN)(4)}(2)Ni(II)(H(2)O)(2)].4H(2)O with L = bpy (2) and phen (3) [bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline] have been prepared and their structures determined by X-ray diffraction methods. The structure of 1 consists of mononuclear [Fe(bpy)(CN)(4)](-) anions, tetraphenylarsonium cations and acetonitrile molecules of crystallization. The iron(III) is hexacoordinated with two nitrogen atoms of the bidentate bpy and four carbon atoms of four terminal cyanide groups building a distorted octahedral surrounding around the metal atom. 2 and 3 are isomorphous compounds whose structure is made up of neutral 4,2-ribbon like bimetallic chains of formula [{Fe(III)(L)(CN)(4)}(2)Ni(II)(H(2)O)(2)] where the [Fe(III)(L)(CN)(4)](-) unit acts as a bis-monodentate bridging ligand toward the trans-diaquanickel(II) units through two of its four cyanide groups in cis positions. The chains exhibit two orientations in the unit cell and they interact with each other through hydrogen bonds involving the coordination and crystallization water molecules together with the uncoordinated cyanide nitrogen atoms of the [Fe(L)(CN)(4)](-) units. Compounds 2 and 3 behave as ferromagnetic Fe(III)(2)Ni(II) chains which interact ferromagnetically at very low temperatures in the case of 2, whereas metamagnetic-like behaviour is observed for with a critical field (H(c)) around 200 G. For H > H(c) the ferromagnetic Fe(III)(2)Ni(II) chains of 3 exhibit a frequency dependence of the out-of-phase ac susceptibility signal at T < 3.5 K.

  8. Ni(ii) ions cleave and inactivate human alpha-1 antitrypsin hydrolytically, implicating nickel exposure as a contributing factor in pathologies related to antitrypsin deficiency.

    PubMed

    Wezynfeld, Nina Ewa; Bonna, Arkadiusz; Bal, Wojciech; Frączyk, Tomasz

    2015-04-01

    Human alpha-1 antitrypsin (AAT) is an abundant serum protein present at a concentration of 1.0-1.5 g L(-1). AAT deficiency is a genetic disease that manifests with emphysema and liver cirrhosis due to the accumulation of a misfolded AAT mutant in hepatocytes. Lung AAT amount is inversely correlated with chronic obstructive pulmonary disease (COPD), a serious and often deadly condition, with increasing frequency in the aging population. Exposure to cigarette smoke and products of fossil fuel combustion aggravates AAT deficiency and COPD according to mechanisms that are not fully understood. Taking into account that these fumes contain particles that can release nickel to human airways and skin, we decided to investigate interactions of AAT with Ni(ii) ions within the paradigm of Ni(ii)-dependent peptide bond hydrolysis. We studied AAT protein derived from human blood using HPLC, SDS-PAGE, and mass spectrometry. These studies were aided by spectroscopic experiments on model peptides. As a result, we identified three hydrolysis sites in AAT. Two of them are present in the N-terminal part of the molecule next to each other (before Thr-13 and Ser-14 residues) and effectively form one N-terminal cleavage site. The single C-terminal cleavage site is located before Ser-285. The N-terminal hydrolysis was more efficient than the C-terminal one, but both abolished the ability of AAT to inhibit trypsin in an additive manner. Nickel ions bound to hydrolysis products demonstrated an ability to generate ROS. These results implicate Ni(ii) exposure as a contributing factor in AAT-related pathologies.

  9. In situ ligand generation for novel Mn(II) and Ni(II) coordination polymers with disulfide ligand: Solvothermal syntheses, structures and magnetic properties

    SciTech Connect

    Han, Yinfeng Wang, Chang'an; Zheng, Zebao; Sun, Jiafeng; Nie, Kun; Zuo, Jian; Zhang, Jianping

    2015-07-15

    Two coordination polymers, ([Mn{sub 2}(L1){sub 2}(μ{sub 2}-H{sub 2}O)(H{sub 2}O){sub 4}]·5H{sub 2}O){sub n}1 and ([Ni(L1)(H{sub 2}O){sub 2}]·2H{sub 2}O){sub n}2 (H{sub 2}L1=2,2′-dithiobisnicotinic acid), were prepared by the solvothermal reactions of the Mn(II) or Ni(II) ions with 2-mercaptonanicotinic acid. In 1, the [Mn{sub 2}(COO){sub 4}] units are connected by the 2,2′-dithiobisnicotinic dianion to form a two-dimensional (4,4)-connected network. In 2, the adjacent Ni(II) ions are connected by the carboxyl groups of the 2,2′