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

Hydride abstraction from the gold (disilyl)ethylacetylide complex [(P)Au{η(1) -C≡CSi(Me)2CH2CH2SiMe2H}] (P=P(tBu)2o-biphenyl) with triphenylcarbenium tetrakis(pentafluorophenyl)borate at -20 °C formed the cationic gold (β,β-disilyl)vinylidene complex [(P)Au=C=CSi(Me)2CH2CH2Si(Me)2](+)B(C6F5)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 (ΔG(≠)=9.7 kcal mol(-1)), presumably via the gold π-disilacyclohexyne intermediate [(P)Au{η(2)-C≡CSi(Me)2CH2CH2Si(Me)2}](+)B(C6F5)4(-).

Duke Scholars

Author Ross A. Widenhoefer Chemistry