Construction And Property Of Coordination Compounds Based On Benzimidazolyl-Pyridine-Containing Ligand

In recent years, coordination polymers that formed by metal salts and organic ligands have attracted great attention of researchers because they have inorganic and organic advantages. Many factors affect the assembly of coordination polymers, such as reaction temperature, pH, and metal centers. In order to achieve new coordination polymers, we need to choose suitable metal centers, organic ligands and control reaction conditions. One common method is using carboxylic acids as auxiliary ligands to regulate the structure of coordination polymers. In this thesis, seven new coordination complexes were successfully obtained by a new ligand3,5-di(1H-benzoimidazol-1-yl)pyridine (L) reacted with transition metal salts and carboxylic acid ligands. On the other hand, the charm of coordination polymers is their interesting properties in the fields of magnetism, gas adsorption, ion exchange and catalysis etc. Therefore, the complexes were characterized by X-ray diffraction, elemental, IR, and thermogravimetric analyses. Furthermore, sorption, catalysis and fluorescence properties of the complexes were studied.This thesis is divided into three parts:1. The development, structure design and property of coordination polymers are summarized in the introduction chapter. 2. The reactions of L with NiSO4·6H2O and carboxylic acids of phthalic acid (o-H2BDC), terephthalic acid (p-H2BDC), isophthalic acid (m-H2BDC), biphenyl-4,4’-dicarboxylic acid (H2BPDC) by solyothermal method yield four one-(ID), two-(2D) and three-dimensional (3D) coordination polymers, namely [Ni(L)(SO4)(H2O)2]·H2O (1),[Ni1.5(L)2(p-BDC)1.5(H2O)3]·3H2O (2),[Ni(L)(m-BDC)(H2O)2](3),[Ni(L)(BPDC)(H2O)2](4). Both1and2show2D structures, the difference between them is, in1, the carboxylic acid does not take part in the formation of the complex, instead, SO42-coordinates with Ni(II).3is an infinite1D chain while4forms a3D framework. The metal centers in the four complexes are all six coordinated, however, ligand L shows two different coordination modes. The pyridine groups of L do not participate coordination except2. Furthermore, the sorption and catalytic of properties1-4were investigated.3. Three new coordination polymers [Zn(L)(m-BDC)](5),[Cd(L)(CCA)]·2H2O (6),[Co(L)(p-BDC)]·H2O (7) with different structures were successfully synthesized by reactions of Zn(II)/Cd(Ⅱ)/Co(Ⅱ) salts with ligand L and carboxylic acids of m-H2BDC,4-carboxycinnamic acid (H2CCA),p-H2BDC, respectively. The L ligands in complexes5-7all adopt bidentate coordination mode with the benzimidazole-N, resulting in formation of2D networks. Complexes6and7have the same (44.62) topology. The fluorescence properties of5and6were also investigated.In summary, we have successfully synthesized a series of novel coordination complexes through assembly of ligand L with various metal salts and carboxylic acid ligands, and the impact of metal centers, coordination mode of the ligand, as well as carboxylic acid ligands were studied. Furthermore, the sorption, catalysis and fluorescence properties of the complexes were explored.