Synthesis, Characterization, and Reactivity of Cationic Gold Diarylallenylidene Complexes

Methoxide abstraction from gold acetylide complexes of the form (L)Au[η 1 ‐C≡CC(OMe)ArAr′] (L=IPr, P( t Bu) 2 ( ortho ‐biphenyl); Ar/Ar′=C 6 H 4 X where X=H, Cl, Me, OMe) with trimethylsilyl trifluoromethanesulfonate (TMSOTf) at −78 °C resulted in the formation of the corresponding cationic gold diarylallenylidene complexes [(L)Au=C=C=CArAr′] +  OTf − in ≥85±5 % yield according to 1 H NMR analysis. 13 C NMR and IR spectroscopic analysis of these complexes established the arene‐dependent delocalization of positive charge on both the C1 and C3 allenylidene carbon atoms. The diphenylallenylidene complex [(IPr)Au=C=C=CPh 2 ] +  OTf − reacted with heteroatom nucleophiles at the allenylidene C1 and/or C3 carbon atom.