Tetracoordinate Co(ii) complexes containing bathocuproine and single molecule magnetism

Abstract

Three Co(II) complexes [Co(bcp)X₂] (bcp = bathocuproine = 4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline; X = Cl, Br, I) were prepared in single crystal forms using a solvothermal method and characterized using chemical and spectroscopic methods. The crystal structures of all three complexes are formed of neutral complex molecules in which the Co(II) atoms are coordinated by one chelate bonded bcp ligand and two halogenido ligands in the form of a distorted tetrahedron. The crystal packing in all structures is governed by π–π stacking and weak C–H⋯X hydrogen bonds with different topologies in the respective complexes. The DC magnetic data showed that all three complexes possess moderate magnetic anisotropy (e.g. D/hc = −5.62 cm⁻¹ for X = Cl). The AC susceptibility measurements indicate the single molecule magnetic behaviour of [Co(bcp)Cl₂]. The bromido and iodido complexes exhibit weak antiferromagnetic interactions within dimeric units held by weak intermolecular interactions, but they do not show a slow magnetic relaxation.