Synthesis,Crystal Structure and Thermal Stability of a New Cadmium(Ⅱ) Polymer Based on 1H-pyrazole-3-carboxylic Acid Ligand

A novel Cd(II) coordination polymer, [Cd Cl(Hpc)H2O]n(1, H2 pc = 1H-pyrazole-3-carboxylic acid), was synthesized by the reaction of Cd Cl2·2.5H2 O with H2 pc, and structurally characterized by IR spectrum, UV-Vis spectrum, elemental analysis, single-crystal X-ray diffraction, as well as thermal analysis. Compound 1 crystallizes in monoclinic, P21/n space group with a = 7.0304(3), b = 10.3047(3), c = 10.6446(4), β = 107.174(4)°, V = 736.78(5) 3, Z = 4, C4H5 Cd Cl N2O3, Mr = 276.95, Dc = 2.497 g/cm3, F(000) = 528.0, μ = 3.281 mm-1, R = 0.0169 and w R = 0.0387. The central metals adopt distorted octahedral geometry. Carboxyl groups of the ligand connect Cd(II) into a one-dimensional chain, which further constructs a two-dimensional network by halogen bridging. Such two-dimensional structures are finally connected into a three-dimensional supramolecular architecture due to the hydrogen bonds and intermolecular π-π interactions. In addition, complex 1 has high thermal stability.