Tuning the Lewis acidity of difluorido gold(iii) complexes: the synthesis of [AuClF₂(SIMes)] and [AuF₂(OTeF₅)(SIMes)]

Abstract

The synthesis and structural characterisation of the difluorido organo gold(iii) complexes [AuClF2(SIMes)] and [AuF2(OTeF5)(SIMes)] are presented. The substitution of a fluorido ligand in [AuF3(SIMes)] by an OTeF5 group increases the Lewis acidity of the Au moiety. A scale for carbene affinities is presented, which correlates calculated and experimental values for the Lewis acidity of the metal centre in akin compounds.

Trifluoromethylation of [AuF3(SIMes)]: Preparation and Characterization of [Au(CF3)xF3−x(SIMes)] (x=1–3) Complexes

“…The molecular structure of [AuF 3 (SIMes)] in the solid state reveals that the Au−F bond with the fluorido ligand in trans position to the SIMes ligand is about 5 pm longer than those to the cis ‐fluorido ligands [14] . In accordance with this finding, a selective substitution of the trans ‐fluorido ligand by a chlorido or a pentafluoridoorthotellurato (OTeF 5 ) ligand was recently reported by us [43] . Hence, the trifluoromethylation of [AuF 3 (SIMes)] is expected to yield trans ‐[Au(CF 3 )F 2 (SIMes)] ( 1 ).…”

“…(3)( bothh ighlightedi nb old)a nd similar, literature-known compounds. [43] The 13 Cc hemical shift of uncoordinatedS IMes, whichh as by definition aS IMes affinity of 0kJmol À1 ,isa lso included. [55] Figure 7.…”

Metathesis Reactions between Heavy d-8 Fluorides and I(III)–Pyridine Complexes

“…1-4). [1][2][3][4][5][6][7] In recent work led by Toste and Nevado in organometallic compounds such as 1-3, it has been shown that the Au(III)-F bond may be displaced by boronic acids, leading to reductive elimination and bond formation reactions, indicating potential utility for the Au-F bond. 1,2 In addition to the structurally characterized examples, Riedel and co-workers have studied the solution phase chemistry of pyridine-AuF 3 mixtures.…”

Reactivity Studies of Cationic Au(III) Difluorides Supported by N-Ligands

“…To date there has been only one report of manipulating an Au-F bond with -TMS in which Riedel replaced an Au(III)-F with chloride or triflate of an NHC-AuF3 complex using the corresponding -TMS reagent. 15 To demonstrate that our Au(III)-F system was compatible with TMS metathesis reactions we sought to generate a known compound, tetrakis pyridine species 8H. 20 The TMS-pyridine cations 7R were generated by direct reaction between TMS-OTf and the appropriate pyridine following literature procedure, and can be isolated and stored for future use.…”

“…The chemistry of organometallic and coordination complexes containing an Au-F bond is underdeveloped, with only 8 unique compounds for Au( I) [1][2][3][4][5][6] and 15 for Au(III) [7][8][9][10][11][12][13][14][15][16] as well as a single Au(II) complex 17 having been characterized by X-ray crystallography. The first was described in 2005, with most examples being reported in the past 5 years as interest in the area increases.…”