Heterometallic 3d-4f Single-Molecule Magnets: Ligand and Metal Ion Influences on the Magnetic Relaxation

Abstract

Six tetranuclear 3d–4f single-molecule magnet (SMM) complexes formed using N-n-butyldiethanolamine and N-methyldiethanolamine in conjunction with ortho- and para-substituted benzoic acid and hexafluoroacetoacetone ligands yield two families, both having a butterfly metallic core. The first consists of four complexes of type {Co2(III)Dy2(III)} and {Co2(III)Co(II)Dy(III)} using N-n-butyldiethanolamine with variation of the carboxylate ligand. The anisotropy barriers are 80 cm–1, (77 and 96 cm–1—two relaxation processes occur), 117 and 88 cm–1, respectively, each following a relaxation mechanism from a single DyIII ion. The second family consists of a {Co2(III)Dy2(III)} and a {Cr2(III)Dy2(III)}..