Synthesis And Properties Of Metal-organic Coordination Polymer With Two Different Ligands As Co-ligands

The design and synthesis of novel metal-organic coordination polymershave attracted researchers’ intensively interests not only for their intriguingstructural topologies but also for their potential applications as functionalmaterials in gas storage and separation, catalysis, magnetism, nonlinear optics,luminosity and so on. In order to expand the structure and properties ofcoordination polymers, we use mixed organic ligands to connect metal ions. Inthis thesis, we choose4,4’-bipyridine as the main ligand, formate and2,6-dimethylpyridine-3,5-dicarboxylic acid as auxiliary ligand, to assemble withtransition metal ions and afforded three coordination polymers undersolvothermal conditions. The main results can be summarized as follows:An unusual2D coordination polymer, namely,[Cu (HCO2)(bpy)]+·(NO-3)(bpy=4,4’-bipyridine)1has been constructed under solvothermal conditions,employing4,4′-bipyridine and formate as organic ligand. In the crystal structureof1, Cu (II) cations are bridged by HCOO-ligand to form infinite1-D zigzagchains, and such1-D zigzag chains are further connected by the4,4’-bpybridges to form a2-D layer. The layers are stacked along the c-axis in an -ABAB-sequence. Compound1exhibits a weak ferromagnetic couplingbetween Cu2+ions, and also has a good chemical stability. In addition，structuretransformation property is also observed after seven days immersion in NaCland NaBr aqueous solution.Two coordination polymers,[Zn2(MPDC)2(4,4’-Bpy)(DMF)]·(DMF)2and[Zn2(mpdc)2(bpy)(H2O)2]2·H2O3have been successfully synthesized byemploying4,4’-bipyridine and2,6-dimethylpyridine-3,5-dicarboxylic acid asorganic ligand. Compound2shows a three-dimensional (3D) networkframework with1-D channels along the a-axis. From the view of topology, theframework of2can be represented as a2,3,4-connected net. In addition,compound2exhibits strong photoluminescent emissions in the solid state atroom temperature. Compound3is a2-D coordination polymer with helicalmotifs, and then further connected by hydrogen bonds to assemble a3-Dsupramolecular network. And pH value may be the key factor that influences thecrystal growth.