Synthesis, Structure and Thermal Properties of Two New Nickel(II) Coordination Polymers Based on Diphenic Acid and Bis(Imidazole) Ligands

Abstract

Two novel nickel(II) coordination polymers, Ni(DPA)(BIX) (1) and Ni2(DPA)2(FBIX)2·H2O (2) (H2DPA = diphenic acid, BIX = 1,4-bis(imidazol-1-ylmethyl)benzene and FBIX = 2,3,5,6-tetrafluoro-1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized under the hydrothermal conditions and characterized by IR, elemental analysis and single crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 35.504(4) A, b = 7.6014(9) A, c = 19.894(2) A, β = 121.607(2)°, V = 4,572.6(9) A3, Z = 8, R 1 = 0.0461 and wR 2 = 0.1193. Complex 2 crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 21.623(2) A, b = 13.9245(15) A, c = 19.743(3) A, β = 119.2360(10)°, V = 5,187.2(12) A3, Z = 4, R 1 = 0.0399 and wR 2 = 0.1034. Complex 1 affords a two-dimensional (2D) wave-like layer network based on the intersection of Ni-BIX and Ni-DPA chains, while complex 2 is an interesting three-dimensional (3D) 4-connected network with a point symbol of (65.8). A careful structural comparison reveals the similarity of the Ni(II) coordination geometry and ligand binding mode. The significant discrepancy of their network structures may be attributed to the fluorinated substituent group. Two novel nickel(II) coordination polymers have been synthesized under the hydrothermal conditions. Complex 1 affords a two-dimensional (2D) wave-like layer network based on the intersection of Ni-BIX and Ni-DPA chains, while complex 2 is an interesting three-dimensional (3D) 4-connected network with (65.8) topology. The results show that the substituent group plays a significant role in the assembly process.