Hydrothermal Synthesis and Crystal Structure of One 3D Coordination Polymer of Cobalt(II) Achieved from 1,1′-Biphenyl-2,2′,6,6′-tetracarboxylic Acid Ligand

A new three-dimensional coordination polymer {[Co（BPTC）0.5（bix）]′（H2O）}n （1, H4BPTC = 1,1′-biphenyl-2,2′,6,6′-tetracarboxylic acid, bix = 1,3-bis（imidazol-l-ylmethyl）-benzene） has been synthesized by the hydrothermal method and characterized by IR, elemental analysis, and single-crystal X-ray analysis. The crystal is of orthorhombic, space group Pbcn with a = 13.2975（10）, b = 13.8424（12）, c = 22.6367（17） A, CoC22H19N4Os, Mr = 478.34, V = 4166.7（6） A3, Dc = 1.525 g/cm^3, F（000） = 1968,μ = 0.867 mm^-1, S = 1.023 and Z = 8. The final R = 0.0683 and wR = 0.1529 for 3655 observed reflections with I 〉 20（I）. In the title complex, the 2D Co-BPTC layer is formed through self-assembly of Co（II） ions and bridging BPTC4-ligands in a molar ratio of 2：1. The metal-organic lattice layers are further united together through the second bridging ligand bix to form a 3D metal-organic framework. The thermal stability of the title complex was studied by thermal gravimetric （TG） and differential thermal analysis （DTA）.