Synthesis and applications of [Au(NCPh)2]+, a versatile labile gold(I) intermediate

Abstract

The [Au(NCPh) 2 ] + cation has been isolated and synthesized in high yields by the oxidation of gold powder in the presence of NOBF 4 . It represents a labile form of gold(), which has been shown to be a valuable synthon for the synthesis of a wide range of gold() complexes and especially of a variety of gold() amines which have opened new synthetic routes for the isolation of organometallic gold() complexes.

Homoleptic Gold Acetonitrile Complexes with Medium to Very Weakly Coordinating Counterions: Effect on Aurophilicity?

“…All presented [Au(NCMe) 2 ] + [WCA] À salts ([WCA] À = [BF 4 ] À , [14] (2a)[ GaCl 4 ] À (2b) , [B(CF 3 ) 4 ] À (2c), [Al(OR F ) 4 ] À (2d)) werep repared through direct oxidation of elemental gold in acetonitrile with nitrosyl salts of weakly coordinatinga nions [NO] [14] and by Yaua nd Mingos, [13] according to Eq. (2), [13] and confirmt hat the salt is very reactive and unstable.N evertheless, by pickingt he crystals at low temperature (À30 8C) and under inert conditions, it was possible to determinei ts crystal structure. As the macroscopicn eedle-like shape of the crystalssuggests, the molecular (11), N1ÀO1 22.476 (11).…”

“…[9] In 1964, the related[ NO] + [ClO 4 ] À was used for M = Au, [10] but the resulting [Au(NCMe) 2 ] + [ClO 4 ] À ,w hich was only characterizedb ye lemental analysis, is highly sensitive to light and water and already decomposesi nt he absence of acetonitrile vapor.L ater,t he more stable [Au(NCMe) 2 ] + [SbF 6 ] À was prepared from [Au(CO) 2 ] + [SbF 6 ] À in superacids, providing the only crystallographicallyc haracterized [Au(NCMe) 2 ] + salt reported to date. [11,12] More recently,Y au and Mingos and Shimizu and Rebek oxidized gold with [NO] + [BF 4 ] À in acetonitrile and obtained [Au(NCMe) 2 ] + [BF 4 ] À , [13,14] acompound highly sensitive towards air,l ight, and water (only vibrational spectroscopy,m ass spectrometry). Yaua nd Mingosi ntroduced the more stable benzonitrile complex[ Au(NCPh) 2 ] + [BF 4 ] À as av ersatile but labile gold(I) intermediate.…”

“…Yaua nd Mingosi ntroduced the more stable benzonitrile complex[ Au(NCPh) 2 ] + [BF 4 ] À as av ersatile but labile gold(I) intermediate. [13] In 2011, Echavarren and coworkers synthesized the first gold(I) complexw ith two nitrile ligands that wass table at room temperature, [Au(tmbn) 2 ] + [SbF 6 ] À ,including the more electron-donating 2,4,6-trimethoxybenzonitrile (tmbn) ligand. This complex proveda ne xcellent catalysta nd was the second structurally characterizedb isnitrile complex of Au I .…”

“…Molecular chainstructure of [Au(NCMe) 2 ] + [BF 4 ] À (2a). Selectedb ond lengths []: Au1ÀF1B 3.147(9), Au1ÀN1 1.991(13), N1ÀC1 1.093(18), C1ÀC2 1.46(2), Au2ÀF1C 4.108(11), Au2ÀN2 1.957(13), N2ÀC3 1.141(18), C3ÀC4 1.431(19),A u2ÀF3D 3.796(10), Au2ÀN3 1.974(12), N3ÀC5 1.140(18), C5ÀC6 1.458(19), Au3ÀF2B 3.163(9), Au3ÀN4 1.955(13),N 4 ÀC7 1.145(19),C 7 ÀC8 1.44(2),A u3ÀF3B 3.211(10), Au3ÀN5 1.963(12),N 5 ÀC9 1.117(19), C9ÀC10 1.46(2), Au4ÀF2 A3.997(13), Au4ÀN6 1.959(13), N6ÀC111.136(19), C11ÀC12 1.43(2).T hermale llipsoids were drawna t5 0% probability.Part of the [BF 4 ] À anions are transparent and the hydrogen atomsa re omitted for clarity.…”

Expedient Syntheses of Neutral and Cationic Au(I)–NHC Complexes

“…The σ-donor lone pair on the N atom of acetonitrile is weakly antibonding, and upon complexation, electron donation from the lone pair to the gold center would be expected to remove weakly antibonding electrons from the CN bond, thereby strengthening it and increasing νC≡N. 37 Indeed, blue-shifted values of νC≡N were measured for 5a-d (Table 6) relative to non-coordinated acetonitrile (νC≡N = 2254, 2293 cm -1 , doublet). 38 Unfortunately, the poor resolution and small range of νC≡N prohibits meaningful comparison to known metrics of -accepting potential of ligands.…”