Coordination microenvironment perturbed single-ion magnet behavior in β-diketone Dy(III) complex

A β-diketonate mononuclear dysprosium complex, [Dy(DBM)2(bpy)(CH3OH)2]·Cl- (1) (DBM = dibenzoylmethane, bpy = 2,2’-bipyridine), has been prepared and structurally and magnetically characterized. The metal centers in 1 adopt approximately square-antiprismatic (SAP) coordination environment with D4d axial symmetry. Magnetic investigations unveil that 1 displays a slow magnetic relaxation of SMM behavior with the effective barrier (Ueff) of 25.13 K under zero dc field as well as 68.30 K in attendance of 1200 Oe dc field. The comparative studies of known Dy(III)-based SIMs with DBM ligand show that the energy barriers can be significantly arranged by adjusting the distortion of the SAP configuration on DyIII ions. Ab initio calculations demonstrate that relaxation of the magnetization for 1 takes place mainly via the first excited-state Kramers doublet through Orbach, Raman, and thermally assisted quantum-tunnelling mechanisms.