Synthesis And Properties Of Coordination Polymers Constructed By Carboxylate And Nitrogen-containing Heterocycle Ligands

Metal-Organic Frameworks (MOFs) have found extensive application in suchfields as gas absorption, catalysis, optical and magnetic materials. The coordinationpolymers with different topology structure and properties could be obtained throughthe design of organic ligand and the choice of metal ions. Now, many research worksare focused on design and synthesis of novel ligands to construct supramoleculararchitectures.Six nitrogen-containing heterocycle ligands were designed and synthesized:1,2-bis(benzoimidazol-2-yl)ethane (bbe),1,3-bis(benzoimidazol-2-yl)propane (bb2p),1,3-bis(benzoimidazol-1-yl)propane (bb1p),1,3-bis(2-methyl-benzoimidazol-1-yl)propane (bmbp),1,4-bis(benzoimidazol-1-yl)butane (bbb) and1,4-bis(2-methyl-benzoimidazol-1-yl)butane (bmbb).Through hydrothermal method, by using5-hydroxyisophthalic acid (HO-H2BDC)as the first ligand and these six nitrogen-containing heterocycles as the second ligands,as well as CoCl2or Co(NO3)2as metal salts, six cobalt coordination polymers wereprepared:{[Co(HO-BDC)(bbe)](H2O)}n(1),{[Co(O-BDC)(bb2p)](H2O)}n(2),{[Co(HO-BDC)(bb1p)]}n(3),{[Co(HO-BDC)(bmbp)2](H2O)2}n(4),{[Co(HO-BDC)(bbb)]}n(5) and {[Co2(HO-BDC)2(bmbb)2](H2O)3}n(6).The structures and properties of these coordination polymers were characterizedby many kinds of analysis methods, such as elemental analysis, thermal gravityanalysis, X-ray single crystal diffraction, and fluorescence analysis.