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.