The First Azide((mu)1,1)-Bridged Binuclear Cobalt(II)-Imino Nitroxide Complex with Ferromagnetic Behavior

The first azide((mu)1,1)-bridged binuclear cobalt(II) complex with a chelated imino nitroxide radical, [Co2(immepy)2(N3)4]·2EtOH, was structurally and magnetically characterized, where immepy = 4,4,5,5-tetramethyl-2-(6ʹ-methyl-2ʹ-pyridyl) imidazoline-1-oxyl. Five nitrogen atoms complete the coordination sphere of the Co(II) ion, showing a distorted trigonal bipyramid geometry. Two N3- anions act as bridges between cobalt ions in the (mu)1,1 coordination mode, resulting in a binuclear structure with an inversion center. Magnetic studies show that ferromagnetic couplings occurred between the adjacent cobalt(II) ions through N3-((mu)1,1) bridges, and antiferromagnetic couplings between the cobalt(II) ions and organic radicals.