Abstract

In this work, we describe for first time, the structure and magnetic characterization of the one dimensional catena cis-[Ni(?-ox)(H 2O) 2] ? (1), which was obtained by solvothermal synthesis. Cis-[Ni(?-ox)(H 2O) 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 [1 0 1] 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 2.5-255 K, at applied fields of 0.10 and 0.25 kOe. The plot of ? MT(T) shows antiferromagnetic interactions between the Ni(II) centres. The experimental data were fitted between 255 and 30 K, 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 -57 cm -1, which is much higher that the obtained for the trans-analogue. Irreversibility between ZFC and FC measurements below 9 K was observed, indicating some kind of magnetic ordering. © 2011 Elsevier B.V. All rights reserved.