Synthesis and magnetic studies of copper(II)-lanthanide(III) heterobinuclear complexes bridged by N,N′-bis[3-(dimethylamino)propyl]oxamido

Ten new copper(II)-lanthanide(III) heterobinuclear complexes bridged by N,N'-bis[3(dimethylamino)propyl]oxamido dianions (dmoxpn) and end-capped with 2,2'-bipyridine (bpy), namely, Cu(dmoxpn)Ln(bpy)(2)(NO3)(3) (Ln = La, Nd, Sin, Eu, Gd, Tb, Dy, Ho, Er, Yb), have been synthesized and characterized by elemental analyses, molar conductivity measurements, and spectroscopic (IR, UV, ESR) studies. The Cu(dmoxpn)Gd(bpy)(2)(NO3)(3) complex was further characterized by variable-temperature magnetic susceptibility (4.2similar to300 K) measurements and the magnetic data have been also used to deduce the indicated heterobinuclear structure., The results derived from least-squares fit of the experimental data have confirmed that the adjacent copper(II) and gadolinium(III) ions through the oxamido-bridge in the complex are ferromagnetically coupled with the exchange integral J((Cu-Gd)) = +8.59 cm(-1). A plausible mechanism for the ferromagnetic coupling betwecn gadolinium(III) and copper(II) is discussed in terms of spin-polarization.