Synthesis And Characterization Of Coordination Polymers Based On2-(Pyridine-3-yl)-1H-4,5-imidazoledicarboxylate Ligand

In this thesis, we have prepared five new coordination polymers by using2-（pyridine-3-yl）-1H-4,5-imidazoledicarboxylic acid （H₃PyImDC） as organic ligandunder hydro/solvothermal conditions.Three novel isomorphic coordination polymers [Zn（HPyImDC）H₂O]（1）,[Mn（HPyImDC）H₂O]（2）,[Co（HPyImDC）H₂O]（3） have been synthesized from2-（pyridine-3-yl）-1H-4,5-imidazoledicarboxylic acid under hydrothermal conditions. Allthe compounds crystallize in P2₁2₁2₁chiral space group and possess left-hand helicalchains and right-hand helical chains along the [010] and [100] directions, respectively.Two types of helical chains connect with each other to form an interesting2D bilayerstructure which extending to a3D supermolecular structure through thehydrogen-bonding interactions. Topology analysis shows that the H₃PyImDC ligands andmetal centers can be regarded as3-connected T-shaped nodes and thus leading to a（3,3）-connected network with vertex symbol of （8²·10）.Compound1exhibits strong fluorescent emission in the solid state at roomtemperature and compound2exhibits antiferromagnetic properties. Additionally, thermalgravimetric analysis （TGA） shows that three compounds retain high thermal stabilities.Two novel Cu-based coordination polymers [Cu₅（HPyImDC）₄·（NH₄）₃]（4） and[Cu₃（H₂O）₂（HPyImDC）₂(C₃N₂H₁₀)]（5） based on H₃PyImDC ligand have beensolvothermally synthesized. Single-crystal X-ray diffraction analyses reveal thatcompound4is a3D framework with open channels along [010] direction, which isconstructed from1D tubes, and the framework can be simplified into a novel（3,4）-connected network with Schl fli symbol of （6².14⁴）（6².8）₄. Compound5exhibits3Dsupermolecular structure constructed by1D tubes via hydrogen-bonding interactions.Compounds4and5are the first example relating to Cu （I） and Cu （I, II） coordinationpolymers based on H₃PyImDC ligands. Further characterizations including elementalanalyses, IR spectra, thermogravimetric analyses have been studied.