Acid Ligands (acid + ligand)

Distribution by Scientific Domains
Chemistry94%
Distribution within Chemistry
General & Introductory Chemistry22%
Organic Chemistry10%

Kinds of Acid Ligands

  • amino acid ligand
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    Selected Abstracts

    Syntheses, Structures and Luminescence Properties of Ln-Coordination Polymers Based on Flexible Thiodiacetic Acid Ligand

    CHINESE JOURNAL OF CHEMISTRY, Issue 8 2009
    Xiangyang HOU
    Abstract Two novel lanthanide complexes with the formulas [Ln2(tda)3(H2O)2]n [Ln=Sm (1), Dy (2), H2tda=thiodiacetic acid] have been prepared by using the corresponding lanthanide salt and H2tda under hydrothermal conditions. Single crystal X-ray diffraction studies show that the two compounds are isostructural and present a 2D network based on the 1D metallic chain, in which an edge-sharing dinuclear polyhedral [Ln2O16] was found to be the building unit of the 1D chains. Interestingly, in the network, the tda ligands exhibit two different coordination modes, including the mode La: bis(syn,syn -bridging bidentate, chelating-bridging tridentate), and mode Lb: bis(chelating- bridging tridentate, syn, anti- bridging bidentate). Furthermore, through the tda ligand in modes La and Lb, the 1D metallic chains are cross-linked to generate a 2D network structure with (3,4,5,6)-connected (47·68)(44·66)(45·6)- (46)(43) topology. Photoluminescence measurements indicate that the dysprosium complex is yellow emitters, and the samarium complex shows salmon pink light emission in the solid state at room temperature. [source]

    Prediction of Decomposition Temperature for Lanthanide Complexes Involving Cyclopentadienyl and Benzohydroxamic Acid Ligand by ANNs

    CHINESE JOURNAL OF CHEMISTRY, Issue 10 2002
    Yi-Min Sun
    Abstract The decomposition temperatures of the lanthanide organic complexes (,5 -C5H5)2 Ln(C6H5CONHO) involving cyclopentadienyl and benzohydroxamic acid ligands were calculated and predicted by the model based on ANNs (artificial neural networks) method. The comparison was carried out between results from ANNs method and traditional regression method. It is proved that ANNs could be used more efficiently for the prediction of decomposition temperature of lanthanide organic complexes. [source]

    Synthesis, Characterization, and Sensitizing Properties of Heteroleptic RuII Complexes Based on 2,6-Bis(1-pyrazolyl)pyr­idine and 2,2,-Bipyridine-4,4,-dicarboxylic Acid Ligands

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2007
    Athanassios I. Philippopoulos
    Abstract Starting from the Ru(bpp)Cl3 precursor (1), a family of novel heteroleptic RuII complexes of the general formulae [Ru(bpp)(dcbpyH)(X)] [X = Cl, (2a), NCS,, (3)] and Na[Ru(bpp)(dcbpy)(CN)] (4) with the ligands 2,6-bis(1-pyrazolyl)pyridine (bpp) and 2,2,-bipyridine-4,4,-dicarboxylic acid (dcbpyH2) has been synthesized, spectroscopically characterized, and attached to nanocrystalline TiO2 electrodes to be tested as solar cell sensitizers. Addition of HCl to (2a) led to the corresponding cationic derivative [Ru(bpp)(dcbpyH2)Cl]Cl (2b). All complexes were characterized by FT-IR, FT-Raman, UV/Vis, 1H NMR spectroscopy, elemental analysis, and mass spectrometry. Complex 4 and the previously reported [Ru(bdmpp)(dcbpyH2)Cl](PF6) (5) [bdmpp is 2,6-bis(3,5-dimethyl-1-pyrazolyl)pyridine] were characterized by single-crystal X-ray diffraction. The photo-electochemical properties of the dyes 2,4 were investigated and the efficiency of the corresponding dye-sensitized solar cells was compared to the sensitizing performance of the cis -[Ru(dcbpyH)2(NCS)2](NBu4)2 (N719) dye.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

    Copper-Catalyzed Cross-Coupling of Sulfonamides with Aryl Iodides and Bromides Facilitated by Amino Acid Ligands.

    CHEMINFORM, Issue 5 2006
    Wei Deng
    No abstract is available for this article. [source]

    A novel three-dimensional copper(I) coordination polymer constructed from a copper,bromide net and nicotinic acid ligands

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009
    Ming-Hua Yang
    The title compound, poly[,3 -bromido-(pyridine-3-carboxylato-,N)copper(I)], [CuBr(C6H5NO2)]n, is a novel coordination polymer based on a copper,bromide net and nicotinic acid ligands. The asymmetric unit contains one copper(I) ion, one bromide ligand and one nicotinic acid ligand, all on general positions. The CuI atom is tetrahedral and coordinated by three bridging Br atoms and the N atom from the nicotinic acid ligand. The Cu,Br units form alternating six-membered chair-patterned rings in net-like layers. The attached nicotinic acid units point alternately up and down. The layers are assembled into a three-dimensional network via intermolecular O,H...O and C,H...Br hydrogen-bonding interactions. [source]

    Poly[triaqua(,4 -4-carboxybenzenesulfonato-,4O:O,:O,,:O,,,)(4-carboxybenzenesulfonato-,O)strontium(II)]

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009
    G. Prochniak
    This study presents the coordination modes and two-dimensional network of a novel strontium(II) coordination polymer, [Sr(C7H5O5S)2(H2O)3]n. The eight-coordinate Sr2+ ion is in a distorted bis-disphenoidal coordination environment, surrounded by four sulfonate and one carboxyl O atom from five benzenesulfonate ligands, two of which are symmetry unique, and by three O atoms from three independent aqua ligands. The compound exhibits a monolayer structure with coordination bonds within and hydrogen bonds between the layers. The ,4 acid ligand bridges the metal ions in two dimensions to form a thick undulating monolayer with a hydrophobic interior and hydrophilic surfaces. A second independent monoanion is arranged outward from both sides of the monolayer and serves to link adjacent monolayers via carboxyl,water and water,carboxyl hydrogen bonds. [source]

    Probing the supramolecular interaction synthons of 1-benzofuran-2,3-dicarboxylic acid in its monoanionic form

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009
    Rajesh Koner
    1-Benzofuran-2,3-dicarboxylic acid (C10H6O5) is a dicarboxylic acid ligand which can readily engage in organometallic complexes with various metal ions. This ligand is characterized by an intramolecular hydrogen bond between the two carboxyl residues, and, as a monoanionic species, readily forms supramolecular adducts with different organic and inorganic cations. These are a 1:1 adduct with the dimethylammonium cation, namely dimethylammonium 3-carboxy-1-benzofuran-2-carboxylate, C2H8N+·C10H5O5,, (I), a 2:1 complex with Cu2+ ions in which four neutral imidazole molecules also coordinate the metal atom, namely bis(3-carboxy-1-benzofuran-2-carboxylato-,O3)tetrakis(1H -imidazole-,N3)copper(II), [Cu(C10H5O5)2(C3H4N2)4], (II), and a 4:1 adduct with [La(H2O)7]3+ ions, namely heptaaquabis(3-carboxy-1-benzofuran-2-carboxylato-,O3)lanthanum 3-carboxy-1-benzofuran-2-carboxylate 1-benzofuran-2,3-dicarboxylic acid solvate tetrahydrate, [La(C10H5O5)2(H2O)7](C10H5O5)·C10H6O5·4H2O, (III). In the crystal structure, complex (II) resides on inversion centres, while complex (III) resides on axes of twofold rotation. The crystal packing in all three structures reveals ,,, stacking interactions between the planar aromatic benzofuran residues, as well as hydrogen bonding between the components. The significance of this study lies in the first crystallographic characterization of the title framework, which consistently exhibits the presence of an intramolecular hydrogen bond and a consequent monoanionic-only nature. It shows further that the anion can coordinate readily to metal cations as a ligand, as well as acting as a monovalent counter-ion. Finally, the aromaticity of the flat benzofuran residue provides an additional supramolecular synthon that directs and facilitates the crystal packing of compounds (I),(III). [source]

    Analysis of Dopamine and Tyrosinase Activity on Ion-Sensitive Field-Effect Transistor (ISFET) Devices

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2007
    Ronit Freeman
    Abstract Dopamine (1) and tyrosinase (TR) activities were analyzed by using chemically modified ion-sensitive field-effect transistor (ISFET) devices. In one configuration, a phenylboronic acid functionalized ISFET was used to analyze 1 or TR. The formation of the boronate,1 complex on the surface of the gate altered the electrical potential associated with the gate, and thus enabled 1 to be analyzed with a detection limit of 7×10,5,M. Similarly, the TR-induced formation of 1, and its association with the boronic acid ligand allowed a quantitative assay of TR to be performed. In another configuration, the surface of the ISFET gate was modified with tyramine or 1 to form functional surfaces for analyzing TR activities. The TR-induced oxidation of the tyramine- or 1 -functionalized ISFETs resulted in the formation of the redox-active dopaquinone units. The control of the gate potential by the redox-active dopaquinone units allowed a quantitative assay of TR to be performed. The dopaquinone-functionalized ISFETs could be regenerated to give the 1 -modified sensing devices by treatment with ascorbic acid. [source]

    A Ru-Hbpp-Based Water-Oxidation Catalyst Anchored on Rutile TiO2,

    CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 4 2009
    Laia Francàs
    Abstract In support of a split: A water oxidation catalyst based on ruthenium bis-(2-pyridyl)pyrazole anchored on rutile TiO2 was prepared. The performance of this new material with regard to its capacity to catalytically oxidize water to molecular oxygen in a heterogeneous phase was evaluated. Two organic ligands based on bis-(2-pyridyl)pyrazole (Hbpp) functionalized with a para -methylenebenzoic acid (Hbpp-Ra) or its ester derivative (Hbpp-Re) were prepared and characterized. The ester-functionalized ligand was then used to prepare a series of related dinuclear ruthenium complexes of general formula [RuII2(L- L)(bpp-Rn)(trpy)2]m+ (L-L=,-Cl, ,-acetato, or (H2O)2; n=e or a; trpy=2,2,:6,,2,,-terpyridine; m=2 or 3). The complexes were characterized in solution by 1D and 2D,NMR spectroscopy, UV/Vis spectroscopy, and electrochemical techniques. The [RuII2(,-Cl)(bpp-Re)(trpy)2](PF6)2 complex was further characterized in the solid state by X-ray diffraction. The complexes containing the free carboxylic acid ligand were anchored onto rutile TiO2 and treated with 0.1,M triflic acid solution to generate the homologous water-oxidation catalysts TiO2 -[RuII2(H2O)2(bpp-Ra)(trpy)2]2+. This new hybrid material catalytically oxidizes water to molecular oxygen in a heterogeneous manner using CeIV as chemical oxidant. The generation of molecular oxygen is accompanied by the formation of carbon dioxide as well as some leaching of the Ru catalyst. [source]

    Syntheses and Crystal Structures of Copper and Silver Complexes with New Imine Ligands , Air-Stable, Photoluminescent CuIN4 Chromophores

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2003
    Goutam Kumar Patra
    Abstract A series of new imine ligands [1 (C12H12N2S2), 2 (C12H12N2S2), 3 (C24H18N4S2), and 5 (C30H27N7)] have been synthesized (1 and 2 are structural isomers). CuI and AgI complexes of the nonconjugated dithiophene-diimine ligands 1, 2 and the tripodal imine-amine ligand 5 have also been prepared and thoroughly characterized by spectroscopic techniques as well as by X-ray diffraction. In cyclic voltammetry at a glassy carbon milli electrode in anhydrous dichloromethane under dry N2, the corresponding CuI complexes [6 (2C12H12N2S2·CuClO4), 7 (2C12H12N2S2·CuClO4), and 12 (C30H27N7·CuClO4)] show quasi-reversible CuII/I couples with high redox potentials (1.001 V for 6, 0.958 V for 7, and 0.692 V for 12, vs. Ag/AgCl). This indicates that the ,-acid ligands 1, 2, and 5 preferentially stabilize copper(I) over copper(II). The CuIN4 chromophores in the complexes 6, 7, and 12 display photoluminescence in dichloromethane at room temperature. The related silver complexes of the same three ligands 10 (2C12H12N2S2·AgClO4), 11 (2C12H12N2S2·AgClO4), and 13 [C30H27N7·Ag(CH3CN)ClO4] reveal similar structural features but lack specific photophysical properties. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Palladium-Catalyzed Suzuki,Miyaura Cross-Coupling Using Phosphinous Acids and Dialkyl(chloro)phosphane Ligands

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2006
    Christian Wolf
    Abstract The use of eleven palladium complexes having monomeric and ,-chloro-bridged dimeric structures and either bulky dialkyl- and diarylphosphinous acid ligands (POPd, POPd-Br, POPd1, POPd2, POPd6, POPd7, Ph1-Phoxide) or dialkyl(chloro)phosphane ligands (PXPd, PXPd2, PXPd6, PXPd7) for Suzuki,Miyaura coupling reactions has been evaluated. Screening and optimization of catalyst loading, solvent, temperature, and base showed that excellent results can be obtained with electron-deficient and electron-rich aryl iodides, bromides, and chlorides in the presence of 2.5 mol-% of palladium,phosphinous acid POPd, (tBu2POH)2PdCl2, in 1,4-dioxane using cesium carbonate as base. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

    Clean and Flexible Modification Strategy for Carboxyl/Aldehyde-Functionalized Upconversion Nanoparticles and Their Optical Applications

    ADVANCED FUNCTIONAL MATERIALS, Issue 24 2009
    Huan-Ping Zhou
    Abstract Rare-earth upconversion nanoparticles (UCNPs) exhibit great potential in luminescent biolabels and other multifunctional probes; however, their applications are limited by their low water solubility and the lack of binding groups. To address these problems, a clean and flexible strategy to modify hydrophobic monodisperse UCNPs into hydrophilic ones that are capped with functional groups is developed. The modification process is implemented by direct oxidation of oleic acid ligands with ozone under specific conditions, where the oleic acid (OA) ligands on the surface of the UCNPs can be converted into azelaic acid ligands (HOOC(CH2)7COOH) or azelaic aldehyde HOOC(CH2)7CHO, as is revealed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) measurements. This oxidation process has no significant side-effects on the morphology, phase, composition, or luminescent properties of the UCNPs. Free carboxylic acid groups on the surface endow the UCNPs with good water solubility, while aldehyde groups at the surface provide binding sites for amino-containing molecules via Schiff-base condensation, such as 2-(4-aminophenylethylyl)-5-methoxy-2-(2-pyridyl)thiazole (MPTEA) and 2-aminoethanethiol hydrochloride (NH2CH2CH2SH·HCl, HEMA). A Ce4+ sensor is constructed based on the dual-emission arising from the different spectral responses of MPTEA and the UCNPs. Facilitated by the covalent linkage between the terminal aldehyde group on the UCNPs and the amino group in HEMA, a hybrid structure of UCNPs and Au NPs is fabricated. The effective coupling between the aldehyde group and the amino group suggests that these functionalized UCNPs have potential in combining other functional units for simultaneous biolabeling, or other optical applications. [source]

    Collectin structure: A review

    PROTEIN SCIENCE, Issue 9 2000
    Kjell Håkansson
    Abstract Colleetins are animal calcium dependent lectins that target the carbohydrate structures on invading pathogens, resulting in the agglutination and enhanced clearance of the microorganism. These proteins form trimers that may assemble into larger oligomers. Each polypeptide chain consists of four regions: a relatively short N-terminal region, a collagen like region, an ,-helical coiled-coil, and the lectin domain. Only primary structure data are available for the N-terminal region, while the most important features of the collagen-like region can be derived from its homology with collagen. The structures of the ,-helical coiled-coil and the lectin domain are known from crystallographic studies of mannan binding protein (MBP) and lung surfactant protein D (SP-D). Carbohydrate binding has been structurally characterized in several complexes between MBP and carbohydrate; all indicate that the major interaction between carbohydrate and collectin is the binding of two adjacent carbohydrate hydroxyl group to a collectin calcium ion. In addition, these hydroxyl groups hydrogen bond to some of the calcium amino acid ligands. While each collectin trimer contains three such carbohydrate binding sites, deviation from the overall threefold symmetry has been demonstrated for SP-D, which may influence its binding properties. The protein surface between the three binding sites is positively charged in both MBP and SP-D. [source]

    Poly[hexaaquabis(,4 -4-carboxybenzenesulfonato)bis(,3 -4-carboxybenzenesulfonato)calcium(II)dipotassium(I)]

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009
    G. Prochniak
    This study presents the coordination modes and crystal organization of a calcium,potassium coordination polymer, poly[hexaaquabis(,4 -4-carboxybenzenesulfonato-,4O1:O1,:O1,,:O4)bis(,3 -4-carboxybenzenesulfonato-,2O1:O1,)calcium(II)dipotassium(I)], [CaK2(C7H5O5S)4(H2O)6]n, displaying a novel two-dimensional framework. The potassium ion is seven-coordinated by four sulfonate and one carboxyl O atom located on five different acid ligands, two of which are unique, and by two symmetry-independent water O atoms. A pair of close potassium ions share two inversion-related sulfonate O-atom sites to form a dimeric K2O12 unit, which is extended into a one-dimensional array along the a -axis direction. The six-coordinate Ca2+ ion occupies a special position (),at (0, , ) and is surrounded by four sulfonate O atoms from two inversion-related pairs of unique acid monoanions and by two O atoms from aqua ligands. The compound displays a layered structure, with K2O12 and CaO6 polyhedra in the layers and aromatic linkers between the layers. The three-dimensional scaffold is open, with nano-sized channels along the c axis. [source]

    A novel three-dimensional copper(I) coordination polymer constructed from a copper,bromide net and nicotinic acid ligands

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009
    Ming-Hua Yang
    The title compound, poly[,3 -bromido-(pyridine-3-carboxylato-,N)copper(I)], [CuBr(C6H5NO2)]n, is a novel coordination polymer based on a copper,bromide net and nicotinic acid ligands. The asymmetric unit contains one copper(I) ion, one bromide ligand and one nicotinic acid ligand, all on general positions. The CuI atom is tetrahedral and coordinated by three bridging Br atoms and the N atom from the nicotinic acid ligand. The Cu,Br units form alternating six-membered chair-patterned rings in net-like layers. The attached nicotinic acid units point alternately up and down. The layers are assembled into a three-dimensional network via intermolecular O,H...O and C,H...Br hydrogen-bonding interactions. [source]

    Crystallographic report: The [bis(,5 -cyclopentadienyl)titanium(IV)-bis(L -methionine)] dichloride

    APPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2004
    Radim Bína
    Abstract The structure of ionic complex [Cp2Ti(L -Met)2]2+[Cl,]2 (where Cp = ,5 -C5H5) possessing C2 symmetry is presented. Discrete cationic units with distorted tetrahedral geometry around the central titanium atom are connected through intermolecular H···Cl bonds between ammonium group protons of ,-amino acid ligands and chloride anions. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Amino Acid Ligand Chirality for Enantioselective Syntheses

    CHEMISTRY & BIODIVERSITY, Issue 6 2010
    Károly Micskei
    Abstract Amino acids are attractive sources of chirality in stoichiometric or catalytic transition metal/organic chemistry. In spite of easy availability and other advantages, the application of these ligands is hindered by several problems. Now, at the dawn of emerging d- amino acid biochemistry, efforts in this direction are becoming increasingly important. The results of research on application of amino acid ligands for transition-metal reagents in organic syntheses are reviewed in the present work. [source]

    Prediction of Decomposition Temperature for Lanthanide Complexes Involving Cyclopentadienyl and Benzohydroxamic Acid Ligand by ANNs

    CHINESE JOURNAL OF CHEMISTRY, Issue 10 2002
    Yi-Min Sun
    Abstract The decomposition temperatures of the lanthanide organic complexes (,5 -C5H5)2 Ln(C6H5CONHO) involving cyclopentadienyl and benzohydroxamic acid ligands were calculated and predicted by the model based on ANNs (artificial neural networks) method. The comparison was carried out between results from ANNs method and traditional regression method. It is proved that ANNs could be used more efficiently for the prediction of decomposition temperature of lanthanide organic complexes. [source]