Straightforward Synthetic Access to gem‐Diaurated and Digold σ,π‐Acetylide Species

Abstract

The more the merrier: Following previous investigations on the synthesis of organogold complexes by using [Au(IPr)(OH)], a high‐yielding straightforward methodology for the synthesis of gem‐diaurated and σ,π‐acetylide species via a dinuclear gold hydroxide complex [{Au(IPr)}2(μ‐OH)][BF4] (see scheme) has now been developed.

Methyl‐, Ethenyl‐, and Ethynyl‐Bridged Cationic Digold Complexes Stabilized by Coordination to a Bulky Terphenylphosphine Ligand

“…It also features ao ne-bond 13 C-1 Hc oupling of 129 Hz, which indicates symmetric AuÀCH 3 ÀAu coordination, void of any agostic interactions.Athree-center-two-electron (3c-2e) bond is also in accord with single-crystal X-ray analysis and DFT studies (see below). Thel atter is shorter than the average value found in other gem-digold compounds [10c, [14][15][16] and than the Au-Aud istance of 2.878 i n metallic gold, [18] indicating an important contribution of aurophilicity to the bonding within the {Au(CH 3 )Au} + triangular core of 3. Thec entral {Au 2 (m-CH 3 )} unit forms an early isosceles triangle,w ith two very similar AuÀCH 3 bonds (2.210(5) and 2.227(4) ) and a Au-Aus eparation of 2.7120 (8) .…”

“…[16] Finally,i ti sn oteworthy that complexes 4 and 5 may be viewed as isolobal analogues to the ethenium (C 2 H 5 + )a nd ethynium (C 2 H 3 + )i ons,r espectively,t hat is,p rotonated ethylene and acetylene.F or the two species,t here is theoretical consensus on structures in which H + interacts with a p-component of the carbon-carbon multiple bond. In contrast, all substituted acetylide complexes with abridging m-CCR unit reported to date have structures of the s,p-type.…”

“…[5c,10] Likewise,r elevant, commonly proposed intermediates,s uch as cationic gold(I) alkylidene,v inylidene,a llenyl, and other species,h ave been structurally characterized. [2g, 13] Cationic digold species of the type [Au 2 (m-R)L 2 ] + ,w here Lrepresents aneutral ligand, commonly atertiary phosphine or an N-heterocyclic carbene (NHC), and Ri saformally monoanionic hydrocarbon-derived group such as phenyl, [10c, 14] alkenyl, [15] or acetylide, [16] have been known for many years (Figure 1, structure A). [2g, 13] Cationic digold species of the type [Au 2 (m-R)L 2 ] + ,w here Lrepresents aneutral ligand, commonly atertiary phosphine or an N-heterocyclic carbene (NHC), and Ri saformally monoanionic hydrocarbon-derived group such as phenyl, [10c, 14] alkenyl, [15] or acetylide, [16] have been known for many years (Figure 1, structure A).…”

Quantum chemical insight into C–H⋯F bonding interactions between noncovalently bonded ion-pairs in N-heterocyclic carbene complexes of gold(I) [(NHC*)2Au]+[PF6]−and gold(III) [(NHC*)2AuCl2]+[PF6]−

“…Triple-z basis sets augmented by two sets of polarization function have been used for all the elements. The (1s) 2 of carbon, nitrogen and fluorine, (1s2s2p) 10 of phosphorus, chlorine and, (1s2s2p3s3p3d4s4p4d) 46 core electrons of gold were treated by the frozen core approximation [93]. An auxiliary set of s, p, d, f, and g STOs was used to fit the molecular densities and to present the Coulomb and exchange potentials accurately in each SCF cycle [92].…”

Direct Evidence for the Origin of Bis‐Gold Intermediates: Probing Gold Catalysis with Mass Spectrometry

“…(Figure 1B). [7] Although gold acetylides can be readily prepared from terminal alkyne under various conditions, [8] one critical question is whether the gold-catalyzed terminal alkyne activation takes place through σ,π-dual activation instead of simple π-activation. [9] …”