cis-[Ni(μ-ox)(H2O)2]∞: Metal organic coordination polymer assembled by oxalate ligand: Structural and magnetic characterization

Abstract: In this work, we describe for first time, the structure and magnetic characterization of the one dimensional catena cis-[Ni(μ-ox)(H2O)2]∞ (1), which was obtained by solvothermal synthesis. Cis-[Ni(μ-ox)(H2O)2]∞ crystallizes in a C2/c spatial group. The asymmetric unit contains only one type of nickel atom, oxalate ligand and water molecules. The chain backbone is constructed by the bis-chelating coordination mode of the oxalate ligand, presenting a zigzag chain in the [101] direction. The nickel ions have a distorted octahedral geometry, surrounded by six oxygens, four of them from two different oxalate ligands and the other two from the cis-coordinated water molecules. Thermal dependence of the magnetic susceptibility of (1) was studied in a temperature range of 2.5–255K, at applied fields of 0.10 and 0.25kOe. The plot of χ M T(T) shows antiferromagnetic interactions between the Ni(II) centres. The experimental data were fitted between 255 and 30K, using an empirical expression for a chain of equally spaced Ni(II) centres. The best fit of the experimental date gave a J value of −57cm−1, which is much higher that the obtained for the trans-analogue. Irreversibility between ZFC and FC measurements below 9K was observed, indicating some kind of magnetic ordering. [Copyright &y& Elsevier]