Ferromagnetic coupling by orthogonal magnetic orbitals in a heterodinuclear CuIIVIV=O complex and in a homodinuclear CuIICuII complex

The heterodinuclear complex [(LCuVIVO)-V-II] 1 was synthesized by using a new unsymmetric dinucleating ligand based on 1,8-naphthalenediol, whereas the homodinuclear (CuCuII)-Cu-II complex 2 has a bridging beta-diketimineamid unit. Here we report on the synthesis, molecular structures, and magnetic properties of 1 and 2. In the solid state, both complexes dimerize to tetranuclear entities 1(2) and 2(2). The intradimer interaction in both complexes is ferromagnetic because of the orthogonality of the magnetic orbitals (J(12) = +45.6 cm(-1) in 1 and +4.8 cm(-1) in 2). The interdimer interaction in 1 is also ferromagnetic, giving a S-t = 2 ground state.