The Organic Ammonium Counterion Effect on Slow Magnetic Relaxation of the [Er(hfac)₄]⁻ Complexes

Abstract

The first mononuclear anionic erbium complex [Er(hfac)4]− (hfac = hexafluoroacetylacetone) with an organic ammonium cation [(CH3)4N+] as the counterion was synthesized and structurally and magnetically characterized. The coordination geometries around the Er ions are square antiprisms with pseudo-D4d symmetry. The complex shows distinct field-induced slow magnetization relaxation, which is described by a combination of Orbach (Ueff/kB~28.54(8) K.) and direct mechanisms. Quantum chemical calculations were performed to analyze the magnetic properties of the complex under consideration.

Keywords

• mononuclear complexes of rare earth elements with β-diketone ligands
• ligand environment geometry
• single-molecule magnets (SMMs)
• slow magnetic relaxation
• anisotropy barrier