Synthesis, characterization and magnetic study of mu-oxamido-bridged copper(II)-lanthanide(III) heterobinuclear complexes

Tell new mu -oxamido-bridged copper(II)-lanthanide(III) heterobinuclear com plexes described by the overall formula Cu(Br(4)Obbz)Ln(phen)(2)NO3 (Ln = Y , La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er), where Br(4)obbz denotes the oxamido- N,N'-bis(3,5-dibromobenzoato) and phen represents 1,10-phenanthroline, have been synthesized and characterized by the elemental analyses, magnetic mom ents (at room temperature), molar conductivity measurements and spectroscop ic (IR, UV, ESR) studies. The temperature dependence of the magnetic suscep tibility of Cu(Br(4)obbz)Gd(phen)(2)NO3 complex was measured over the range 4.2-300 K. The least-squares fit of the experimental susceptibilities base d on the spin Hamiltonian operator, (H) over cap=-2J (S) over cap (1).(S) o ver cap (2), yielded J= +3.7 cm(-1). This result indicates the presence of a weak ferromagnetic spin-exchange interaction between Gd(III) and Cu(II) i ons.