Synthesis and magnetism of μ-oxamido-bridged Cu2IILnIII - type heterotrinuclear complexes (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er)

Eight new Cu2IILnIII - type (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er) heterotrinuclear complexes bridged by N,N'-bis (2-aminopropyl)oxamidocopper(II) [Cu(oxdn)], namely Cu2(oxdn)Ln(NO3)3, have been synthesized and characterized by elemental analyses, molar conductivity measurements and spectroscopic (IR, UV, ESR) studies. Magnetic susceptibility measurements (4.2 ∼300 K) and studies of Cu2(oxdn)Gd(NO3)3 complex have revealed that the central gadolinium(III) and terminal copper(II) ions are ferromagnetically coupled with the exchange integral J(Cu-Gd) = +2.98 cm-1, while an antiferromagnetic coupling is detected between the terminal copper(II) metal ions with the exchange integral J'(Cu-Gd) = -0.75 cm-1, on the basis of the spin Hamiltonian operator [H -2J(SCu1-SGd+SCu2+SGd)-2J'(SCu1SCu2)]. (author)