Formation of Hydroxyindenyl and Vinylidene Ligands by Reaction of Internal Alkynes with Cp*Fe(CO)(NCMe)Ph

The reactivity of Cp*Fe­(CO)­(NCMe)­Ph (1) (Cp* = pentamethyl­cyclopentadienyl) with internal alkynes has been studied. Reactions of 1 with dihydrocarbyl-substituted alkynes result in the formation of pentamethyl­cyclopentadienyl hydroxyindenyl sandwich complexes. A divergent reaction pathway is observed in the case of bis­(trimethylsilyl)­acetylene, where a neutral Fe vinylidene is isolated. The reactions of hydrocarbyl trimethylsilyl-substituted alkynes with complex 1 result in the formation of the pentamethyl­cyclopentadienyl hydroxyindenyl sandwich complexes. This reactivity suggests the necessity of two trimethylsilyl groups for vinylidene formation.