Synthesis and Magnetic Studies of Copper(II)-Lanthanide(III) Heterobinuclear Complexes Bridged by N,N'-Bis[3-(dimethylamino)propyl]oxamido

摘要

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'-bipyri-dine (bpy),namely,Cu(dmoxpn)Ln(bpy)_2(NO_3)_3 (Ln=La,Nd,Sm,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(NO_3)_3 complex was further characterized by variable-temperature magnetic susceptibility (4.2approx300 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 between gadolinium(III) and copper(II) is discussed in terms of spin-polarization.