Trifluoromethylation of [AuF (SIMes)]: Preparation and Characterization of [Au(CF ) F (SIMes)] (x=1-3) Complexes.

Trifluoromethylation of [AuF (SIMes)] with the Ruppert-Prakash reagent TMSCF in the presence of CsF yields the product series [Au(CF ) F (SIMes)] (x=1-3). The degree of trifluoromethylation is solvent dependent and the ratio of the species can be controlled by varying the stoichiometry of the reaction, as evidenced from the F NMR spectra of the corresponding reaction mixtures. The molecular structures in the solid state of trans-[Au(CF )F (SIMes)] and [Au(CF ) (SIMes)] are presented, together with a selective route for the synthesis of the latter complex. Correlation of the calculated SIMes affinity with the carbene carbon chemical shift in the C NMR spectrum reveals that trans-[Au(CF )F (SIMes)] and [Au(CF ) (SIMes)] nicely follow the trend in Lewis acidities of related organo gold(III) complexes. Furthermore, a new correlation between the Au-C bond length of the molecular structure in the solid state and the chemical shift of the carbene carbon in the C NMR spectrum is presented.