Cu–Ni hetero-bimetallic compounds, Part 1: Preparation, structure and properties of [Cu 0.05Ni 0.95(bpy) 2(ox)]·4H 2O

Abstract

New bimetallic compound [Cu x Ni 1− x (bpy) 2(ox)]·4H 2O ( x = 0.05, ox = oxalato, bpy = 2,2′-bipyridine) was synthesized and chemically characterized. Its crystal structure is molecular. The octahedron around the metal central atom is deformed due to coordination by one bidentate oxalate anion and two bpy ligands. There are four uncoordinated water molecules in the asymmetric unit. The metal site is occupied by both Cu(II) and Ni(II) atoms in the 5:95 ratio. The complex molecules interact with water molecules through hydrogen bonds and, moreover, π–π interactions between aromatic rings lead to a 1D arrangement of molecules. The susceptibility data measured down to 2 K were analyzed using strong-coupling theory and the best agreement with the experimental data were found for g = 2.1, D/ k = 5.6, E/ k = 0.35, J/ k = 0.2. The dehydration starts at 30 °C. As a final product of its thermal decomposition a solid solution of Cu x Ni 1− x O was detected by X-ray powder diffraction.