Syntheses, crystal structures and magnetism of azide-bridged five-coordinate binuclear nickel(II) and cobalt(II) complexes

Abstract

The bulky ligand 2,9-dimethyl-1,10-phenanthroline (dmphen) has been used to construct pentacoordinate transition metal complexes. Two such doubly end-on azido-bridged dinuclear complexes [M2(dmphen)2(μ1,1−N3)2Cl2] [M = Ni (1) or M = Co (2)] have been obtained and characterized by single-crystal X-ray diffraction analysis and magnetic studies. Both complexes consist of dimeric square pyramidal M(II) centers bridged by two end-on azide ligands. Magnetic studies suggest that both complexes display intramolecular intermetallic ferromagnetic coupling. The coupling constants for pentacoordinate azide-bridged dinuclear Ni(II) complexes are found to decrease with the increasing Ni–N–Ni bond angle.