Synthesis And Characterizations Of Transition Metal/Lanthanide Coordintion Polymers Of N-containing Heterocyclic Ligands

Metal-organic frameworks have diverse topologically architecture, high porosity and high specific surface area. At the same time, the pore size is adjustable, controllable and stable. Lots of literatures report that a target coordination polymer may be obtained by choosing appropriate organic ligands and metal centers. Nitrogen containing carboxylic acid is a kind of important multifunctional organic ligands, which have received more attention for the ability of constructing diverse, high-dimension and stable metal organic frameworks.This paper focuses on the synthesis and characterization of transition metal/lanthanide coordination polymers of rigid N-containing heterocyclic ligands. By using 4-(pyridin-4-yl)benzoic acid or 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine as the first ligand, in the presence of the second ligand, we synthesized a series of transition metal/lanthanide coordination polymers hydrothermally. These complexes have been characterized by single crystal X- ray diffraction, infrared, XRD and fluorescence analysis methods.1、A mononuclear transition metal complexe [Cu(pydca)(Hpyba)(H2O)]2(1) was obtained by adopting 4-(pyridin-4-yl)benzoic acid, pyridine-2,6-dicarboxylic acid and copper(II) bromide as raw materials. Hpyba = 4-(pyridin-4-yl)benzoic acid, H2 pydca = pyridine-2,6-dicarboxylic acid.2 、 Two isostructural lanthanide complexes, [Ln2(μ3-OH)(Hpydca)(pyba)3(H2O)]n(Ln=Nd,2; Pr,3), were obtained by selecting 4-(pyridin-4-yl)benzoic acid and pyridine-2,6-dicarboxylic acid as mixed ligands, while adding lanthanide oxides under the condition of hydrothermal. In the structure of 2, the μ3-OH bridges three lanthanide ions forming a trimetallic unit, which connect another trimetallic unit through edging-sharing to generate a stable core building unit of [Nd4(OH)2(pyba)2].3、Selecting 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine as the first ligand, the benzene-1,3-dicarboxylate as the second ligand, while adding transition metal salt and lanthanides nitrate, four heteronucle ar coordination polymers of 3d-4f with three-diamension network, were obtained: [Ln M(Htyba)(tyba)(m-bdc)(NO3)]·NO3}n](4-7)(Ln/M=Nd/Cu,4; Sm/Cu,5; Eu/Zn,6; Gd/Zn,7). Htyba=4′-(4-carboxyphen yl)-2,2′:6′,2″-terpyridine,m-H2bdc= benzene-1,3-dicarboxylate.