Crystal structure and magnetic properties of the octahedral complexes of Ni(II) with 3-imidazoline nitroxides

This paper reports on our studies of the crystal structures and magnetic pr operties of five mixed-ligand octahedral complexes-of Ni(II) with 3-imidazo line nitroxides Ni(RL)(2)X-2, where RL are deprotonated enaminoketone deriv atives of 3-imidazoline nitroxide with different substituents R (CF3, Ph) i n the side chain, and X is pyridine, dimethylsulfoxide, or semi-phenanthrol ine. It is established that this type of heterospin system is characterized by an intramolecular exchange interaction parameter (J) of an order of 10 cm(-1). Substitution of the N-donor diamagnetic pyridine or phenanthroline by the O-donor dimethylsulfoxide in the coordination sphere of the metal de creases J by 2-3 cm(-1). A transition from trans to cis-coordination of the enaminoketone ligands and variation of the R substituent in the chelate ri ng do not affect the value of J.