Predetermined ferromagnetic coupling via strict control of M−O−M angles

Abstract

An imidazolidine-phenolate ligand HL yields quadruple bridged ferromagnetic nickel and cobalt dinuclear complexes. The ferromagnetism of these samples is mainly ascribed to the double µ-Ophenolate bridges, on the basis of DFT calculations. These studies demonstrate that the short M-O-M angles of the M2O2 are the optimal ones for maximizing the ferromagnetic contribution in these complexes. And these acute angles, close to 90º, are predetermined by the geometrical constrictions imposed by the ligand itself. Thus, HL is an odd polydentate donor that induces ferromagnetism per se in its metal complexes by strict control of geometric parameters.