Ferromagnetically coupled heterobinuclear Cu(II)‐Ln(III) complexes with N,N′‐bis(2‐aminoethyl)‐oxamido dianion as a bridged ligand

Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (LnLa, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dianion, Me2bpy is 4,4'-dimethyl-2,2'-bipyridyl, have been synthesized and characterised by elemental analyses, IR, conductivity measurements and electronic spectra. The temperature dependence of the magnetic susceptibility of Cu(oxae)Gd(Me2bpy)2(ClO4)3 has been measured over the range 4–300 K. The least-squares fit of the experimental susceptibilities yielded J = 1.87 cm−1. The observed Gd(III)-Cu(II) coupling is ferromagnetic. One plausible mechanism that can cause a ferromagnetic coupling between Gd(III) and Cu(II) is discussed in terms of spin-polarization.