Striking ligand-disproportionative Cl/aryl scrambling in a simple Au(iii) system. Solvent role, driving forces and mechanisms

Abstract

Aryl rearrangements triggered by Cl⁻ extraction from trans-[Au^III(Rf)₂Cl₂]⁻ (Rf = C₆F₃Cl₂-3,5), led quickly to a mixture of [Au(Rf)₃(solv)], cis-[Au(Rf)₂Cl(solv)] and [Au(Rf)Cl₂(solv)] (solv = OEt₂, OH₂). ¹⁹F NMR and X-ray diffraction studies led us to identify the species present in solution and the role of the solvent in their formation, while DFT calculations confirm the thermodynamic basis of their evolution. Very different Rf–Rf coupling rates are found from (μ-Cl)₂[cis-Au(Rf)₂]₂ or cis-[Au(Rf)₂ClL] species (L = OEt₂, NCMe, Cl⁻) depending on the coordination strength of the ligand or solvent in the fourth position.