Observation of Field-Induced Single-Molecule Magnet Behavior in a Binuclear Co2 Compound with Oh Configuration

Abstract

A binuclear cobalt compound, namely, [Co2(HL)2Cl2(H2O)4]·2Cl·2H2O (1), was synthesized by acylhydrazone Schiff base ligand N 3-(4-pyridyl)-4-hydroxybenzoylhydrazone (HL) and CoCl2·6H2O. The crystal structure study suggests that each CoII ion in 1 is surrounded by two nitrogen atoms and one oxygen atom from ligand, one chloride atom and two oxygen atoms from two water molecules, giving rise to six-coordinated geometry, where two N atoms from two ligands as bridges link two CoII ions. The direct-current (dc) magnetic susceptibility measurements reveal that the antiferromagnetic coupling interaction exists in 1. The alternating-current (ac) magnetic susceptibility measurements indicate that 1 exhibits field-induced slow magnetic relaxation behavior with energy barrier (Ueff) of 53.58 K, standing out among Co2 -SMMs. This study demonstrates that the large magnetic anisotropy of each CoII ion and the weak antiferromagnetic coupling interaction between two CoII ions can improve Co2-SMMs performance effectively.

Keywords: Binuclear cobalt compound, single-molecule magnet, octahedron configuration