Trifluoromethylation of [AuF 3 (SIMes)] with the Ruppert-Prakash reagent TMSCF 3 in the presence of CsF yields the product series [Au(CF 3) x F 3Àx (SIMes)](x = 1-3). The degree of trifluoromethylation is solvent dependenta nd the ratio of the speciesc an be controlled by varying the stoichiometry of the reaction, as evidenced from the 19 FNMR spectra of the correspondingr eactionm ixtures.T he molecular structures in the solid state of trans-[Au(CF 3)F 2 (SIMes)] and [Au(CF 3) 3 (SIMes)] are presented, together with as elective route for the synthesis of the latter complex.C orrelation of the calculated SIMes affinity with the carbene carbon chemical shifti nt he 13 CNMR spectrum reveals that trans-[Au(CF 3)F 2 (SIMes)] and [Au(CF 3) 3 (SIMes)] nicely follow the trend in Lewis acidities of related organo gold(III) complexes. Furthermore, an ew correlation between the AuÀC carbene bond length of the molecular structure in the solid state and the chemical shift of the carbene carbon in the 13 CNMR spectrum is presented.

The trifluorides of the two high field strength elements yttrium and holmium are studied by periodic density functional theory. As a lanthanide, holmium also belongs to the group of rare earth elements (REE). Due to their equivalent geochemical behavior, both elements form a geochemical twin pair and consequently, yttrium is generally associated with the REE as REE+Y. Interestingly, it has been found that DFT/DFT+U describe bulk HoF3 best, when the 4f-electrons are excluded from the valence region. An extensive surface stability analysis of YF3 (PBE) and HoF3 (PBE+Ud/3 eV/4f-in-core) using two-dimensional surface models (slabs) is performed. All seven low-lying Miller indices surfaces are considered with all possible stoichiometric or substoichiometric terminations with a maximal fluorine-deficit of two. This leads to a scope of 24 terminations per compound. The resulting Wulff plots consists of seven surfaces with 5–26% abundance for YF3 and six surfaces with 6–34% for HoF3. The stoichiometric (010) surface is dominating in both compounds. However, subtle differences have been found between these two geochemical twins.

We report on a comprehensive reactivity study starting from [AuF3(SIMes)] to synthesize different motifs of monomeric gold(III) fluorides. A plethora of different ligands has been introduced in a mono‐substitution yielding trans‐[AuF2X(SIMes)] including alkynido, cyanido, azido, and a set of perfluoroalkoxido complexes. The latter were better accomplished via use of perfluorinated carbonyl‐bearing molecules, which is unprecedented in gold chemistry. In case of the cyanide and azide, triple substitution gave rise to the corresponding [AuX3(SIMes)] complexes. Comparison of the chemical shift of the carbene carbon atom in the 13C{1H} NMR spectrum, the calculated SIMes affinity and the Au−C bond length in the solid state with related literature‐known complexes yields a classification of trans‐influences for a variety of ligands attached to the gold center. Therein, the mixed fluorido perfluoroalkoxido complexes have a similar SIMes affinity to AuF3 with a very low Gibbs energy of formation when using the perfluoro carbonyl route.

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