Spin Crossover Phenomenon in Coordination Compounds

Control of Exchange Interactions in Trinuclear Complexes Based on Orthogonal Magnetic Orbitals

The reaction of copper(II) acetate with the tetradentate Schiff base like ligand H4L {(E,E)-[{diethyl 2,2′-[4,5-dihydroxy-1,2-phenylenebis(iminomethylidyne)]bis(3-oxobutanoate)}] leads to the formation of the square planar N2O2 coordinated complex [H2CuL]. Reaction of two equivalents of this complex with copper(II) acetylacetonato or vanadyl(IV) acetylacetonato yields the trinuclear complexes [V(O)Cu2L2][N(nBu)4]2·2MeOH (1) and [Cu3L2][N(nBu)4]2·2DMF (2). Both complexes were characterised by using magnetic measurements and X-ray crystallography. Special attention was given to the spin-exchange coupling through the bridging phenylene ring. The principle of strict orthogonality of the magneti…