Synthesis, Characterization And Properties Of Coordination Polymers Based On The N-containing Ligands

Metal coordination polymers have attracted much interest due to diverse topological structuresand potential applications as functional materials in luminescence, absorption, separation, catalysis,magnetism and so on. Recently, the employment of the self-assembly of metal salts with N-donorheterocyclic ligands and multicarboxylates has become an effective approach for constructingcoordination polymers, which can better satisfy the coordination needs of metal ions and result inmore stable structures. So a series of Co(II) coordination polymers derived from seven derivatives offlexible bis(benzimidazole) ligands and varied polycarboxylates have been synthesized byhydrothermal methods and characterized by elemental analyses, IR spectra and single-crystal X-raydiffraction. Moreover, the thermogravimetric analysis (TGA), fluorescence and catalytic performanceshave also been investigated. The main contents are summarized as following:Four Co(II) coordination polymers with different dimensional architectures based onbis(benzimidazole) ligands and polycarboxylates as mixed ligands have been obtained. Compound1displays a1D ladder-like chain.2possesses a2D (4,4) network.3exhibits a3D (3,5)-connected3,5T21framework.4shows a2D honeycomb (6,3) network. In addition, compounds1,2and4arefurther extended into3D supramolecular architectures by hydrogen bonding interactions, indicatingthat supermolecular interactions have a great influence on the self-assembly process and the resultingframeworks.Six new coordination polymers have been hydrothermally synthesized by the reactions of Co(II)salts with dicarboxylates in the presence of5,6-dimethylbenzimidazole-type co-ligands. Complex5forms a1D looped-like chain consisting of two kinds of macrocycles;6and10feature1D ladder-likechains;7and9are both wave-like (4,4) grid two-dimensional coordination polymers;8exhibits a3Dframework with a twofold interpenetrating diamondoid topology. So, the skeletons of N-containingligands and carboxylates have a vital role in determining their final structures.In addition, compounds2,3and9all display a high thermal stability. Compounds except4possess good photoluminescence properties, demonstrating their potential applications in the opticalmaterials. Compounds1~10used as heterogeneous catalysts for the oxidative degradation of methylorange by persulfate as oxidant have also been investigated in detail. Under the same condition, thecomplexes all show positive catalytic activities in the decomposition of methyl orange. Therefore, it isa feasible method to use complexes as catalysts and shows a potential application for the removal oforganic wastewater.