Synthesis and Crystal Structure of One-dimensional Cadmium（II） Coordination Polymer: [Cd2（DTB）(Bpy)2（H2O）2]n （DTB = 1,4-Dinitro-2,3,5,6-tetracarboxylatebenzene Tetravalent Anion;Bpy = 2,2'-Bipyridyl）

A one-dimensional coordination polymer [Cd2(DTB)(Bpy)2(H2O)2]n was synthe- sized by the reaction of hydrate cadmium perchlorate with 1,4-dinitro-2,3,5,6-tetracarboxylateben- zenic acid, sodium hydroxide and 2,2?-bipyridyl in 50% methanol solution by using solvent-thermal method. The crystal belongs to the triclinic system, space group P1 with a = 8.137(3), b = 9.527(3), c = 10.737(4) ?, α = 96.305(6), β = 102.996(5), γ = 101.511(6)°, Z = 1, C30H20Cd2N6O14, Mr = 913.32, Dc = 1.934 g/cm3, V = 784.2(5) ?3, F(000) = 450 and μ = 1.440 mm-1. The structure was refined to R = 0.0497 and wR = 0.0955 for 1870 observed reflections (I > 2σ(I)). In the complex each DTB as a four-dentate ligand bridges four cadmium(II) ions to form a one-dimensional chain structure.