Synthesis, Structure and Magnetic Studies of a Ni(II) Coordination Polymer Constructed from Asymmetrical Tetracarboxylic Acid and N-Donor Ligand

One new tri-nuclear nickel(II) coordination polymer, namely, [Ni3(μ3-O)(as-H2bptc)2(4,4′-bpy)2(H2O)4]n (H4bptc = 2,3,3′,4′-biphenyl tetracarboxylic acid, and 4,4′-bpy = 4,4′-bipyridine) has been synthesised under hydrothermal conditions, and its structure and properties have been characterised by X-ray single-crystal and powder diffraction, infrared spectrum analysis, elemental analysis, thermogravimetric analysis and magnetic susceptibility analysis. The single-crystal diffraction results showed that complex crystallised in the C2/c monoclinic space group was a 3D structure with tri-nuclear Ni(II) secondary building units, in which metal cations were in octahedral coordination geometries. The powder X-ray diffraction indicated that the complex was a pure phase and thermal analysis showed the excellent thermal stability of the complex. Additionally, variable temperature (2–300 K) magnetic measurements indicated antiferromagnetic coupling or spin inclination behaviour in the Ni3 core in the complex.