Synthesis and Characterization of a Gold Vinylidene Complex Lacking π‐Conjugated Heteroatoms

Hydride abstraction from the gold (disilyl)ethylacetylide complex [( P )Au{η 1 ‐CCSi(Me) 2 CH 2 CH 2 SiMe 2 H}] ( P =P( t Bu) 2 o ‐biphenyl) with triphenylcarbenium tetrakis(pentafluorophenyl)borate at −20 °C formed the cationic gold (β,β‐disilyl)vinylidene complex [( P )AuCCS i(Me) 2 CH 2 CH 2 Si (Me) 2 ] + B(C 6 F 5 ) 4 − with ≥90 % selectivity. 29 Si NMR analysis of this complex pointed to delocalization of positive charge onto both the β‐silyl groups and the ( P )Au fragment. The C1 and C2 carbon atoms of the vinylidene complex underwent facile interconversion (Δ G ≠ =9.7 kcal mol −1 ), presumably via the gold π‐disilacyclohexyne intermediate [( P )Au{η 2 ‐ CCSi(Me) 2 CH 2 CH 2 Si (Me) 2 }] + B(C 6 F 5 ) 4 − .