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Mixed Ligands (mixed + ligand)

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Chemistry100%

Terms modified by Mixed Ligands

  • mixed ligand complex
    		•

    Selected Abstracts

    Direct Simultaneous Determination of Cu, Ni and V in Seawater Using Adsorptive Cathodic Stripping Voltammetry with Mixed Ligands

    ELECTROANALYSIS, Issue 10 2005
    A. Cobelo-García
    Abstract An analytical procedure is proposed for the direct simultaneous determination in a single scan of Cu, Ni and V in seawater by means of adsorptive cathodic stripping voltammetry (ACSV) with mixed ligands (DMG and catechol). Optimum conditions for the determination of these three elements were studied. Detection limits of the technique depended upon the reproducibility of the procedura blank, and were found to be 0.5,nM for Cu, 0.4,nM for Ni and 0.3,nM for V. The method is suitable for the analysis of estuarine, coastal and open-ocean waters, and especially to study the metal contamination in areas subject to oil spill events. [source]

    Novel Metallosupramolecular Networks Constructed from CuII, NiII, and CdII with Mixed Ligands: Crystal Structures, Fluorescence, and Magnetism

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2006
    Miao Du
    Abstract Reactions of mixed ligands succinic acid (H2suc) and bent dipyridines, such as 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and its 4- N -donor analog (4-bpo), with inorganic CuII, NiII, and CdII salts yield three new metal-organic coordination frameworks {[Cu(suc)(3-bpo)(H2O)2]·(H2O)1.75}n (1), {[Ni(suc)(4-bpo)(H2O)2]·(H2O)5}n (3), and {[Cd2(suc)2(3-bpo)2(H2O)2]·(H2O)6.75}n (4), in which the metal centers are linked by bridging ligands 3-bpo/4-bpo and suc2, along two directions to form 2D infinite networks. The corrugated 2D nets of 1 and 4, obtained under hydrothermal conditions, align in an interdigitated manner with the presence of significant aromatic-stacking interactions to result in similar 3D architectures. The 2D sheets in 3 are extended by interlayer hydrogen bonds to afford a 3D structure. However, when succinic acid is replaced by fumaric acid (H2fum) in the reaction with 3-bpo and CuII salt, a metallacyclophane [Cu(Hfum)2(3-bpo)(H2O)]2·(3-bpo)2·(H2O)6 (2) is generated. The binuclear coordinated motifs are hydrogen-bonded to the lattice water chains to furnish a unique 3D channel-like framework, in which the guest 3-bpo molecules are accommodated. The thermal stabilities of these new materials were investigated by thermogravimetric analysis (TGA) of mass loss. The magnetic coupling in complexes 1,3 is antiferromagnetic and very small, which is as expected considering the long organic bridges between the paramagnetic centers. The solid-state luminescence properties of 4 reveal an intense fluorescence emission at 378 nm. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

    Iron(III) Chelation: Tuning of the pH Dependence by Mixed Ligands

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2003
    Anne-Marie Albrecht-Gary
    Abstract The iron(III) chelating properties of two heteropodands with 8-hydroxyquinoline and catechol binding groups were examined and compared to those of the corresponding homopodal analogues, O-TRENSOX and TRENCAMS. Like the parent homopodands, the two heteropodands are based on the TREN scaffold and the chelating units are connected by amide groups, TRENSOX2CAMS having two 8-hydroxyquinoline and one catechol arms and TRENSOXCAMS2 one 8-hydroxyquinoline and two catechol moieties. The aqueous coordination chemistry of these ligands was examined by potentiometric and spectrophotometric methods in combination with 1H NMR spectroscopy. The respective pFeIII values showed a cooperative effect of the mixed chelating units. Moreover, the pFeIII dependence on pH showed that the mixed ligands exhibit a higher complexing ability than the parent ligands over the pH range 5,9 which is of biological relevance. This result could be of great interest for medical applications. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Hydrothermal Synthesis, Crystal Structures and Photoluminescence of Two Novel Metal-organic Supramolecular Frameworks Based on Mixed Ligands of Dipyrazino[2,3- f:2,,3,-h]quinoxaline and Pyridine-2,5-dicarboxylic Acid

    CHINESE JOURNAL OF CHEMISTRY, Issue 9 2008
    Xiu-Li WANG
    Abstract Two novel metal-organic frameworks [Zn2(Dpq)2(2,5-pda)2(H2O)2]·2H2O (1) (dipyrazino[2,3- f:2,3,- h]quinoxaline=Dpq) and [Cd2(Dpq)2(2,5-pda)2]·2H2O (2) (pyridine-2,5-dicarboxylic acid=2,5-H2pda) have been obtained from hydrothermal reactions of two different metal(II) nitrates with the same mixed ligands Dpq and 2,5-H2pda, and structurally characterized by elemental analyses, TG, IR spectroscopy, and single-crystal X-ray diffraction analyse. Single-crystal X-ray analyses show that the metal ions are bridged by different coordination modes of 2,5-pda to form a dimer in 1, 2D rhombic grid in 2, respectively. In the compound 1, adjacent dimers are packed through hydrogen bonds and - aromatic stacking interactions to form a distorted , -Po supramolecular structure. In the compound 2, adjacent polymer layers are further linked by hydrogen bonds to form a distorted , -Po 3D supramolecular framework stabilized by - stacking interactions. The different structures of compounds 1 and 2 illustrate the influence of the metal ions and ligands on the self-assembly of polymeric coordination architectures. In addition, the title compounds exhibit blue emission in the solid state at room temperature. [source]

    Characterization by NMR Spectroscopy, X-ray Analysis and Cytotoxic Activity of the Ruthenium(II) Compounds [RuL3](PF6)2(L = 2-Phenylazopyridine or o -Tolylazopyridine) and [RuL'2L"](PF6)2(L', L" = 2-Phenylazopyridine, 2,2'-Bipyridine)

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2005
    Anna C. G. Hotze
    Abstract Tris(ligand) complexes [RuL3](PF6)2 (L = 2-phenylazopyridine or o -tolylazopyridine) and mixed ligand [RuL'2L"](PF6)2 (L' and L" are 2-phenylazopyridine or 2,2'-bipyridine) have been synthesized, structurally characterized and investigated for cytotoxic activity. These complexes are important to study the hypothesis that the compound ,-[Ru(azpy)2Cl2] (azpy = 2-phenylazopyridine) exhibits a high cytotoxicity due to its two cis chloride ligands, which might be exchanged for biological targets as DNA. Molecular structures of mer -[Ru(azpy)3](PF6)2 (1) and mer -[Ru(tazpy)3](PF6)2 (5) (tazpy = o -tolylazopyridine) have been determined by X-ray diffraction. Series of complexes [RuL3](PF6)2 and [RuL'2L"](PF6)2 show interesting NMR spectroscopic data; e.g. the spectrum of mer -[Ru(azpy)3](PF6)2 (1) shows extremely broadened resonances at room temp. but sharpened resonances at low temperature. In the 1H NMR spectra of compounds [Ru(azpy)2(bpy)]2+ and [Ru(bpy)2(azpy)]2+ (bpy = 2,2-bipyridine), respectively, less broadened (room temp.) or completely sharp resonances (room temp.) occur in comparison to 1 (under same conditions). By selecting the right temperature and/or concentration, NMR spectra of these series of compounds have been resolved using 2D COSY and NOESY NMR spectroscopy. Remarkably, the cytotoxicity data against a series of human tumor cell lines (A498, EVSA-T, H226, IGROV, M19, MCF-7 and WIDR) show a moderate cytotoxicity for these series of tris(ligand) complexes. So, even though no chloride ligands are present in these tris(ligand) complexes, a considerable cytotoxic activity is observed. This would imply that the 2-phenylazopyridine ruthenium(II) complexes act by a completely different mechanism than the well-known cisplatin. This finding is important, because an anticancer compound acting via a different mechanism is a prerequisite in designing new anticancer drugs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    H93G myoglobin cavity mutant as versatile template for modeling heme proteins: Magnetic circular dichroism studies of thiolate- and imidazole-ligated complexes

    BIOPOLYMERS, Issue 4-5 2002
    John H. Dawson
    Abstract Recent ligand binding and spectroscopic investigations of the myoglobin H93G cavity mutant are reviewed, revealing it to be a versatile template for the preparation of model heme complexes of defined structure. The H93G myoglobin cavity mutant is shown to be capable of forming mixed ligand adducts because of the difference in accessibility of the two sides of the ferric heme iron. With imidazole bound in the proximal cavity, H93G myoglobin also forms reasonably stable oxyferrous and oxoferryl derivatives, thereby providing a potential system to use for the study of such complexes with proximal ligands other than imidazole. In addition, thiolate-ligated ferric H93G derivatives are described that serve as spectroscopic models for the high-spin ferric state of cytochrome P450. All of the complexes described are characterized with magnetic circular dichroism spectroscopy, and they are compared to the appropriate derivatives of native myoglobin and P450. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 200,206, 2002 [source]

    Direct Simultaneous Determination of Cu, Ni and V in Seawater Using Adsorptive Cathodic Stripping Voltammetry with Mixed Ligands

    ELECTROANALYSIS, Issue 10 2005
    A. Cobelo-García
    Abstract An analytical procedure is proposed for the direct simultaneous determination in a single scan of Cu, Ni and V in seawater by means of adsorptive cathodic stripping voltammetry (ACSV) with mixed ligands (DMG and catechol). Optimum conditions for the determination of these three elements were studied. Detection limits of the technique depended upon the reproducibility of the procedura blank, and were found to be 0.5,nM for Cu, 0.4,nM for Ni and 0.3,nM for V. The method is suitable for the analysis of estuarine, coastal and open-ocean waters, and especially to study the metal contamination in areas subject to oil spill events. [source]

    Three Novel Functional CdII Dicarboxylates with Nanometer Channels: Hydrothermal Synthesis, Crystal Structures, and Luminescence Properties

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2007
    Yu-Peng Tian
    Abstract Three novel functional transition-metal complexes with H2A (H2A = 9-ethylcarbazole-3,6-dicarboxylic acid), Cd(HA)2(H2O)2 (1), [Cd(A)(phen)]·1.5H2O (2) (phen = 1,10-phenanthroline), and Cd(HA)2(bipy) (3) (bipy = 4,4,-bipyridine), have been successfully synthesized by a hydrothermal synthetic method and characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, thermogravimetric analysis, and photoluminescence. The results show that all of the complexes contain nanometer channels, while the coordination modes were changed by the addition of the mixed ligands. The 2D supramolecular open-framework 1 is constructed through hydrogen-bond and aromatic ,,, interactions. 2D coordination polymer 2 is constructed by ,,, interactions between adjacent metal-organic polymeric coordination chains. Interestingly, the 3D supramolecular architecture of 3 first formed 2D grid layers from 1D chains by intermolecular hydrogen bonds and then extended into a 3D structure through aromatic ,,, interactions. Furthermore, strong emissions from these complexes were also changed by the coordination modes in the solid state. However, complexes 1,3 show high thermal stability.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    Iron(III) Chelation: Tuning of the pH Dependence by Mixed Ligands

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2003
    Anne-Marie Albrecht-Gary
    Abstract The iron(III) chelating properties of two heteropodands with 8-hydroxyquinoline and catechol binding groups were examined and compared to those of the corresponding homopodal analogues, O-TRENSOX and TRENCAMS. Like the parent homopodands, the two heteropodands are based on the TREN scaffold and the chelating units are connected by amide groups, TRENSOX2CAMS having two 8-hydroxyquinoline and one catechol arms and TRENSOXCAMS2 one 8-hydroxyquinoline and two catechol moieties. The aqueous coordination chemistry of these ligands was examined by potentiometric and spectrophotometric methods in combination with 1H NMR spectroscopy. The respective pFeIII values showed a cooperative effect of the mixed chelating units. Moreover, the pFeIII dependence on pH showed that the mixed ligands exhibit a higher complexing ability than the parent ligands over the pH range 5,9 which is of biological relevance. This result could be of great interest for medical applications. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    catena -Poly[[[(iminodiacetato-,O)silver(I)]-,3 -2-aminopyrimidine-,3N1:N2:N3] monohydrate]: a one-dimensional silver(I) coordination polymer with mixed ligands

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009
    Di Sun
    The title compound, {[Ag(C4H6NO4)(C4H5N3)]·H2O}n, was synthesized by the reaction of silver(I) nitrate with 2-aminopyrimidine and iminodiacetic acid. X-ray analysis reveals that the crystal structure contains a one-dimensional ladder-like AgI coordination polymer and that N,H...O and O,H...O hydrogen bonding results in a three-dimensional network. The AgI centre is four-coordinated by three N atoms from three different 2-aminopyrimidine ligands and one O atom from one iminodiacetate ligand. Comparison of the structural features with previous findings suggests that the existence of a second ligand plays an important role in the construction of such polymer frameworks. [source]

    Deposition of crystalline copper films from tetranuclear copper (II) complexes without application of reducing atmosphere

    APPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2010
    Muhammad Shahid
    Abstract Crystalline copper films were deposited by aerosol-assisted chemical vapor deposition (AACVD) in the absence of hydrogen from two newly synthesized complexes [Cu(deae)(TFA)]4·1.25THF (1) and [Cu4(OAc)6(bdmap)2(H2O)2]·4H2O (2) [deae = N, N -diethylaminoethanolate, TFA = trifloroacetate, OAc = acetate and bdmap = 1,3-bis(dimethylamino)-2-propanolato]. These precursors were prepared in high yield using mixed ligands and crystallized in tetragonal and triclinic crystal systems with space groups 141/a and P , 1. Complexes 1 and 2 thermally decomposed at 290 and 250 °C, respectively, to yield copper films which were characterized by SEM/EDX for their morphology and composition and PXRD for their crystallinity and phase. These films have smooth morphologies with particle sizes within the range of 0.3,0.6 µm and may find applications in fabrication of ultralarge-scale integrated circuits. Copyright © 2010 John Wiley & Sons, Ltd. [source]