Synthesis and Characterization of Bidentate (P^N)Gold(III) Fluoride Complexes: Reactivity Platforms for Reductive Elimination Studies

Reactivity of [AuF3 (SIMes)]: Pathway to Unprecedented Structural Motifs

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-[AuF2 X(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 13 C{1 H} 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.

Gold(I) α‐Trifluoromethyl Carbenes: Synthesis, Characterization and Reactivity Studies

Aryl trifluoromethyl diazomethanes 2‐R (R=Ph, OMe, CF₃) are readily decomposed by the (o‐carboranyl)diphosphine gold(I) complex 1. The resulting α‐CF₃ substituted carbene complexes 3‐R have been characterized by multi‐nuclear NMR spectroscopy as well as X‐ray crystallography (for 3‐Ph). The bonding situation was thoroughly assessed by computational means, showing stabilization of the electrophilic carbene center by π‐donation from the aryl substituent and backdonation from Au, as enhanced by the chelating P^P ligand. Reactivity studies under stoichiometric and catalytic conditions substantiate typical carbene‐type behavior for 3‐Ph.