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

Abstract

A β-diketonate mononuclear dysprosium compound, [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 an approximately square-antiprismatic (SAP) coordination environment with D_4d axial symmetry. Magnetic investigations unveil that 1 displays slow magnetic relaxation of SMM behavior with an effective barrier (U_eff) of 25.13 K under a zero dc field as well as 68.30 K in the presence of a 1200 Oe dc field. The comparative studies of some known Dy(III)-based SIMs with DBM ligands show that the energy barriers can be significantly tuned by adjusting the distortion of the SAP configuration on Dy^III ions. Ab initio calculations demonstrate that relaxation of the magnetization for 1 mainly takes place via the first excited-state Kramers doublet through Orbach, Raman, and thermally assisted quantum-tunnelling mechanisms.