Dinuclear Rare-Earth β-Diketiminates with Bridging 3,5-Ditert-butyl-catecholates: Synthesis, Structure, and Single-Molecule Magnet Properties

Abstract

The dinuclear β-diketiminato complex [L¹ClDy(μ-Cl)₃DyL¹(THF)] (1) (L¹ = {2,6-ⁱPr₂C₆H₃–NC(Me)CHC(Me)N-2,6-ⁱPr₂C₆H₃}⁻) was obtained by reaction of DyCl₃ with KL¹ in a molar ratio of 1:1 and used for the preparation of the mixed-ligand complex [L¹Dy(μ-3,5-Cat)]₂ (2) by salt metathesis reaction with 3,5-CatK₂ (3,5-Cat −3,5-di-tert-butyl-catecholate). Reactions of 3,5-CatNa₂ with [L²LnCl₂(THF)₂] (Ln³⁺ = Dy, Y) ligated with the less bulky ligand L² = {2,4,6-Me₃C₆H₂–NC(Me)CHC(Me)N-2,4,6-Me₃C₆H₂}⁻ afforded the mixed-ligand THF-containing complexes [L²Ln(μ-3,5-Cat)(THF)]₂ (Ln³⁺ = Dy (3a), Y (3b)). All new complexes were fully characterized, and the solid-state structures were determined by single-crystal X-ray diffraction. Magnetic measurements revealed single-molecule magnet behavior for the dysprosium complexes. Sub-Kelvin μSQUID studies confirm the SMM character of the systems, while CASSCF calculation along with simulation of the experimental data yields an antiferromagnetic interaction operating between the Dy³⁺ ions.