Synthesis,Crystal Structure,Fluorescent Property and DFT Study of a Novel 1D Polymer [Zn(HMICD)(bpy)]_n·2nH_2O

A new one-dimensional(1D) polymer, Zn(HMIDC)(bpy)]_n·2n H_2O(1, H_3MIDC = 2-methyl-imidazole-4,5-dicarboxylic acid, bpy = 2,2?-bipyridine), has been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, UV-vis spectrum and fluorescence measurements. Complex 1 crystallizes in orthorhombic system, space group Pbca with a = 14.404(3), b = 8.6900(17), c = 26.570(5) ?, V = 3325.8(11) ?~3, Dc = 1.700 g/cm~3, M_r = 425.70, Z = 8, F(000) = 1744, μ = 1.522 mm~(-1), the final R = 0.0421 and w R = 0.1018. The Zn(Ⅱ) ion is six-coordinated by O and N atoms from one HMIDC ligand, two O atoms from another HMIDC ligand and two N atoms from the bpy ligand. The HMIDC anion, which acts as a tetradentate ligand, chelates two Zn ions to form a one-dimensional(1D) zigzag chain structure. We analyzed the electronic structure and orbital energies of complex 1 by DFT methods, and the results are consistent with the UV-vis spectrum. And we also discussed the luminescent mechanism of complex 1 in detail.