Synthesis and Properties of μ-Oxamido Heterobinuclear Cu(II)-Mn(II) Complexes

Abstract

Abstract From the planar monomeric fragment Cu(oxpn) where oxpn is N, N′-bis(3-aminopropyl)oxamido, we have synthesized three complexes, namely[Cu(oxpn)Mn(bpy)2](ClO4)2.H2O (1)(bpy = 2, 2′-bipyridyl), [Cu(oxpn)Mn(phen)2](ClO4)2.2H2O (2) (phen = 1, 10-phenanthroline), and [Cu(oxpn)Mn(NO2-phen)](ClO4)2.H2O (3) (NO2-phen = 5-nitro-1, 10-phenanthroline). Based on IR, elemental analyses, electronic spectra and conductivity, the complexes are proposed to have an oxamido-bridged structure and consist of Cu(II) in a planar environment and Mn(II) in a distorted octahedron. The complexes have been characterized by variable-temperature magnetic susceptibility (4-300 K) and the susceptibility data were least-squares fit to the susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for Mn(II) ion Ĥ = −2JS1-S2-DS2 z1, where D is the axial zero-field splitting parameter for the Mn(II) ion. The exchange integral, J, was found to be equal to -10.73 cm−1 in (1) -15.20 cm−1 in (2) and -15-30 cm−1 in (3). This indicates an antiferromagnetic spin exchange interaction among the metal ions.