Synthesis,Structure,Fluorescent Property and Natural Bond Orbital（NBO） Analysis of a One-dimensional Cobalt（III） Complex Containing 1,3-Benzenedicarboxylate and 2-Methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline Ligand

A novel metal-organic coordination polymer Co(m-BDC)(Medpq)·2H2O]n(m-H2BDC = benzene-1,3-dicarboxyalic acid,Medpq = 2-methyldipyrido3,2-f:2',3'-h]quinoxaline) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.The title compound crystallizes in monoclinic,space group C2/c with a = 19.986(4),b = 15.789(3),c = 16.292(3),β = 126.54(3)°,V = 4130.3(14)3,C23H18N4O6Co,Mr = 505.34,Dc = 1.625 g·cm-3,Z = 8,μ = 0.883 mm-1,F(000) = 2072,the final R = 0.0772 and wR = 0.1428.The crystal structure of complex 1 is an infinite zigzag-like chain of hexacoordinate Co3+ ions,in which the Co3+ ions are bridged in two coordination modes by m-BDC2+ ligands and decorated by Medpq ligands,showing a slightly distorted octahedral geometry.Additionally,the compound shows strong fluorescence in the solid state at room temperature.Natural bond orbital(NBO) analysis is performed by using the NBO method built in Gaussian 03 Program.The calculation results show a covalent interaction between the coordinated atoms and Co3+ ions.