Dinuclear Rare-Earth β-Diketiminates with Bridging 3,5-Di<i>tert</i>-butyl-catecholates: Synthesis, Structure, and Single-Molecule Magnet Properties

The dinuclear β-diketiminato complex [L¹ClDy(μ-Cl)₃DyL¹(THF)] (<b>1</b>) (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 (<b>2</b>) by salt metathesis reaction with 3,5-CatK₂ (3,5-Cat -3,5-di-<i>tert</i>-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 (<b>3a</b>), Y (<b>3b</b>)). 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.