Synthesis, crystal structures, and magnetic properties of trinuclear cobalt(II) and nickel(II) complexes with oxamido vanadium(IV)-oxo complex ligand

By using a macrocyclic vanadium(IV)-oxo complex ligand VOL (H2L = 2,3-dioxo-5,6:13,14-dibenzo-7,12-diphenyl-1,4,8,11-tetraazacyclo-tetradeca-7,12-diene) as a precursor, two new trinuclear complexes [(VOL)2Co(C2H5OH)2](ClO4)2·2C2H5OH (1) and [(VOL)2Ni(CH3OH)2](ClO4)2 (2) have been synthesized and characterized by elemental analyses, IR spectroscopy, and power and single-crystal X-ray diffraction. In the two complexes, the central ions cobalt(II) and nickel(II) are connected with two VOL fragments via exo-cis oxamido bridge. Magnetic susceptibility measurements indicate that both complexes 1 and 2 show weak ferromagnetic interactions.