Synthesis and magnetic properties of binuclear copper(II)-cobalt(II) complexes with N,N′-bis (2-aminopropyl)oxamidocopper(II)

Abstract

Three heterobinuclear complexes have been synthesized, namely [Cu(oxap) Co(L) 2](ClO 4) 2 [where L = 2,2′-bipyridyl (bpy), 1,10-phenanthroline (phen) and 5-nitro- 1,10-phenanthroline (NO 2-phen)], where oxap is N,N′-bis(2-aminopropyl)oxamido. Based on IR, elemental analyses, conductivity measurements and electronic spectra, these complexes are proposed to have extended oxamido-bridged structures and to consist of copper(II) in a planar environment and cobalt(II) in an octahedral environment. The complexes have been characterized by variable temperature magnetic susceptibility (4.2-300 K) and the data were fit by least-squares to a susceptibility equation derived from the spin Hamiltonian, Ĥ = −2 JŜ· Ŝ 2− DŜ 2 z1. The exchange integral, J, was found to be −15 cm −1 (for bpy), −24 cm −1 (for phen) and −26 cm −1 (for NO 2-phen), indicating that a weak antiferromagnetic spin-exchange interaction operates between the metal ions.