Mixed-metal cluster carbides and a mixed-metal ketenylidene with nucleophilic carbide sites

Article abstract of DOI:10.1021/om00081a031

The nucleophilic ketenylidene [Fe₃(CO)₉-(CCO)]₂- (III) serves as a convenient mixed-metal carbide precursor. Compound III reacts readily with labile metal carbonyl fragments such as M(CO)₃(NCCH₃)₃ (M = Cr, W) to generate the new clusters [Fe₃MC(CO)₁₃]^2- which contain a nucleophilic carbide ligand similar to that in [Fe₄C(CO)₁₂]^2-. By contrast, treatment of III with Co₂(CO)₈ leads to replacement of one iron vertex, generating a new monoanionic heterometallic ketenylidene [Fe₂Co(CO)₉(CCO)]^- which is less reactive but otherwise chemically similar to III. X-ray cristallographic analysis shows the CCO tilt to be considerably less than in the [Fe₃(CO)₉(CCO)]^2- species.