Ferromagnetic coupling in a chloride-bridged erbium single-molecule magnet

Abstract

We present the first ferromagnetically-coupled Er³⁺ complex with linked, high-anisotropy Er–COT (COT²⁻ = cyclooctatetraene dianion) subunits. The dinuclear complex, [Er(μ₂-Cl)(COT)(THF)]₂, demonstrates single-molecule magnetism with a single, zero-field magnetization relaxation barrier of U_eff = 113 cm⁻¹. This system offers evidence that anisotropy can be preserved in the presence of ferromagnetic linking of the Er–COT subunits, providing a rational means to build strong molecular magnets of tunable dimensionality.