Structural studies of a dinuclear (Cu, Gd) and two trinuclear (Cu-2, Ln) complexes (Ln = Ce, Er). Magnetic properties of two original (Cu, Gd) complexes

With the aim of increasing the number of structurally characterized dimetal lic (Cu-II, Ln(III)) complexes, we have obtained a strictly dinuclear (Cu-I I, Gd-III) complex 1 in which, according to structural data, the two metal ions are triply bridged. Then, we have investigated the capability of Cusal en precursors for complexing lanthanide ions. Structural and magnetochemica l studies show that dinuclear entities with a CuO(2)Ln bridging network can only be isolated with the heavier lanthanide ions such as gadolinium or er bium (complexes 2, 3 and 4) while trinuclear (CuO(2)LnO(2)Cu) complexes are obtained in the case of lighter Ln(III) ions, such as cerium (complex 5) f or example. Ferromagnetic interactions with J values of 4.2 and 3.5 cm(-1) characterize complexes 1 and 2, respectively.