Single-Molecule Magnet Behavior with a Single Metal Center Enhanced through Peripheral Ligand Modifications

Bis(imino)pyridine pincer ligands in conjunction with two isothiocyanate ligands have been used to prepare two mononuclear Co(II) complexes. Both complexes have a distorted square-pyramidal geometry with the Co(II) centers lying above the basal plane. This leads to significant spin–orbit coupling for the d7 Co(II) ions and consequently to slow relaxation of the magnetization that is characteristic of Single-Molecule Magnet (SMM) behavior.