The Synthesis And Catalytic Properties Of Microscale Crystalline Coordination Polymers

Coordination polymers have been an active research field, arising from not only the tunability of their architectures, but also their properties in heterogeneous catalysis,gas storage, sensing, drug delivery, photocatalysis and so on. In comparison with other immobilized systems, CPs have highly ordered crystalline structures, high catalyst loadings, more uniform and isolated catalytic sites, thus eliminating multimolecular catalyst deactivation pathways. CPs have been considered as eco-friendly alternatives for catalysis. The coordination site of multiple N/O can provide metal centers with an unsaturated coordination environment, which is benefical for the catalytic processes. In this paper, a tetrazole ligand5,5’-(1H-imidazole-4,5-diyl)-bis-(2H-tetrazole)(H3idbt) and a tetradentate acid ligand9,9′-spirobifluorene-2,2′,7,7′-tetracarboxylic acid(H4sbtc) have been designed and synthesized. We synthesized five novel complexes under solvothermal conditions.Based on the feature of their structures, they are used as heterogeneous catalysts in particular catalytic reactions to detailedly research the influence of catalytic performance by their structure. The paper includes the following two parts:1. The combination of H3 idbt ligand with zinc ions affords four 2D coordination polymers {[Zn6(idbt)4(phen)4]·3H2O}n(1), {[Zn3(idbt)2(H2O)4]·2H2O}n(2),{[Zn3(idbt)2(bpy)2]·H2O}n(3) and {[Zn3(idbt)2(bMe-bPy)2]·H2O}n(4)(H3idbt =5,5’-(1H-imidazole-4,5-diyl)-bis-(2H-tetrazole), phen = 1,10-phenanthroline, bpy =2,2’-dipyridyl, bMe-bPy = 4,4’-dimethyl-2,2’-dipyridyl) under solvothermal conditions. CPs 1 and 2 as heterogeneous catalysts for the reactions of amino alcohol and dinitriles exerted a influence on the selectivity of the catalytic reactions, yielding mono-oxazolines as the major products. To improve the catalytic efficiency,microscale coordination polymers of 1 and 2 are obtained by using surfactant-mediated hydrothermal methods and a systematic investigation is conducted to explore how different surfactants affect the morphologies and particle sizes of CPs. In addition, a plausible mechanism for the catalytic reaction has been proposed. The solid-state fluorescences of complexes 2–4 have been investigated andthe solid ultraviolet visible spectrum of complexes 1–4 have also been studied.2. A tetradentate acid ligand has been designed, synthesized and charaeterized by NMR, FT-IR and MS. We assembled a H4 sbtc ligand with Co(NO3)2·6H2O by solvothermal synthetic method and synthesized {[Co2(sbtc)·2H2O]·H2O}n(5). Its structure has been charaeterized by single crystal structure analysis. Thermal analyse was carried out so as to examine the thermal stability of the complex. The UV-Vis absorption spectra of the complex 5 was conducted in the crystalline state at room temperature. Complex 5 exhibits strong absorption bands in ultraviolet visible light region.