Vinylidene Compounds from the Reactions of Me₃SiC⋮CSiMe₃ with Tp^Me2Ir Precursors. Protonation to Alkylidene and Iridabenzene Structures

Abstract

Reaction of the Ir(I) butadiene compound Tp Me2 Ir(η 4 -CH 2 C(Me)C(Me) CH 2 ) with the alkyne Me 3 SiC⋮CSiMe 3 gives the vinylidene ( 1 ). A related vinylidene 2 forms when Tp Me2 Ir(Ph) 2 (N 2 ) is reacted with Me 3 SiC⋮CSiMe 3 . Compounds 1 and 2 have been characterized by microanalysis and spectroscopy (IR, 1 H and 13 C{ 1 H} NMR data), and in addition the molecular structure of 1 has been determined by X-ray diffraction. The reactions of these compounds with different protic acids have been investigated. Thus, the vinylidene 2 gives rise to the cationic alkylidene [Tp Me2 Ir(Ph)(Et 2 O)( C(Me)Ph)]BF 4 ( 3 ) when treated with HBF 4, to the neutral chlorocarbene Tp Me2 Ir(Ph)(Cl)( C(Me)Ph) ( 4 ) upon reaction with HCl, and to the neutral alkylidene Tp Me2 Ir(Ph)(κ 1 -O 2 CCF 3 )( C(Me)Ph) ( 5 ) by action of CF 3 COOH. In turn the vinylidene species 1 and CF 3 COOH give rise to the iridabenzene compound ( 6 ), characterized in the solid state by X-ray crystallography.