Stabilization of Lewis Acidic AuF3 as an N-Heterocyclic Carbene Complex: Preparation and Characterization of [AuF3(SIMes)]

Two different reaction routes are described to access the unprecedented trifluoridoorganogold(III) complex [AuF3(SIMes)]. The compound bears the N-heterocyclic carbene SIMes (1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) as a ligand for a molecular Lewis acidic AuF3 unit and was characterized by NMR spectroscopy as well as X-ray crystallography. Apart from the use of a [AuF4](-) salt as precursor, the strong oxidizing compound AuF3 can be employed neat as starting material. The reaction proceeded even in organic solvents in the presence of SIMes as the ligand precursor. Decomposition reactions with the solvent can, therefore, be prevented by using this strategy.