Synthesis and magnetic properties of novel oxamido heterotrinuclear complexes Cu IIM IICu II (M = Mn and Cu)

Abstract

Two novel trinuclear complexes have been synthesized, namely [Cu 2(oxae) 2(H 2O) 2Mn](ClO 4) 2 ( 1) and [Cu 2(oxae) 2Cu](ClO 4) 2 ( 2), where oxae denotes the N, N′-bis(2-aminoethyl)oxamido dianion. Based on IR, elemental analyses, conductivity measurements and electronic spectra, the complexes are proposed to have extended oxamido-bridged structures. The magnetic susceptibility of the complex 1 has been studied in the 4–300 K range and the observed data were fit by least-squares to a susceptibility equation derived from the spin Hamiltonian, H ̂ = −2J( S ̂ 1 S ̂ 2 + S ̂ 2 S ̂ 3)−2J′ S ̂ 1 S ̂ 3 . The exchange integrals, J and J′, were found to be equal to −18 and −0.38 cm −1. This procedure indicates the existence of an antiferromagnetic spin-exchange interaction between the adjacent metal ions. The powder ESR spectrum of complex 1 has been obtained and discussed.