Synthesis and magnetic studies of [Cu(3)(II)Ln(III)] heterotetranuclear complexes with N,N '-bis(3-amino-2,2-dimethylpropyl)oxamidocopper(II)

Eleven new oxamido-bridged Cu(3)(II)Ln(III)-type(Ln = La, Ce, Pr, Nd, Sm, E u, Od, Tb, Ho, Er, Yb) heterotetranuclear complexes, namely Cu-3(Me(2)oxpn) (3)Ln(NO3)(3), where Me(2)oxpn denotes N,N'-bis(3-amino-2,2-dimethylpropyl) oxamido dianion, have been synthesized and characterized by elemental analy ses, molar conductivity measurements, and spectroscopic (IR, UV, ESR) studi es. Cryomagnetic measurements (4.2 similar to 300 K) and studies of Cu-3(Me (2)oxpn)(3)Gd(NO3)(3) complex have revealed that the gadolinium(III) and co pper(II) ions are ferromagnetically coupled with the exchange integral J = +3.88 cm(-1), on the basis of the spin Hamiltonian operator [(H) over cap = -2J((S) over cap (1) . (S) over cap (0) + (S) over cap (2) . (S) over cap (0) + (S) over cap (3) . (S) over cap (0))].