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

Abstract

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.

Ligand-Enabled Oxidative Fluorination of Gold(I) and Light-Induced Aryl–F Coupling at Gold(III)

“…In addition, 19 F NMR spectroscopy shows a doublet at δ – 299.6 ppm with coupling to phosphorus ( J FP = 7.3 Hz). The 19 F NMR chemical shift of 1a falls in the lower range of those found previously for Au­(III) fluoride complexes (δ from −150 to −320 ppm typically). − The small value found for J FP contrasts with the large coupling constants observed for the analogous [(MeDalphos)­Au­(Ar)­F] + complexes with fluorine trans to phosphorus ( J PF ∼ 100 Hz) . This suggests that the oxidative fluorination occurs trans to nitrogen, which can assist in the oxidation of the gold center (this assertion is supported by DFT calculations, vide infra ), and thus the aryl remains trans to phosphorus.…”

“…The methyl Au­(III) complex proved active in fluorine-assisted transmetalation with aryl boronic acids followed by reductive elimination resulting in C­(sp 2 )–C­(sp 3 ) coupling . Fluorine-assisted transmetalation and C­(sp 2 )–C­(sp 2 )/C­(sp) coupling from Au­(III) fluorides have been further investigated by Nevado and co-workers with (C,N)-cyclometalated and (P,N)-chelated complexes. − These Au­(III) fluoride precursors were synthesized using an alternative approach, i.e., halide exchange at Au­(III) using AgF. − …”