Metal atom reactions of cobalt with cyclopentadiene and alkynes: Synthesis of structurally novel organometallic complexes

Article abstract of DOI:10.1021/ic50207a006

The reactions of cobalt atoms and cyclopentadiene with various alkynes such as hexafluorobutyne, trifluoropropyne, and diphenylacetylene have been found to yield a variety of new organometallic compounds including both mono- and multimetal complexes. In general the products obtained fall into four categories: (1) complexes containing ligands resulting from dimerization or trimerization of the alkyne usually accompanied by hydrogen addition, i.e., (η-C₅H₅)Co[C₄H₂(CF ₃)₄], (η-C₅H₅)₂Co₂[C₅H ₂F(CF₃)₃], (η-C₅H₅)₂Co₂[C₆H ₅(CF₃)₃], [η,-C₅(CH₃)₅]Co[C₄H ₂(CF₃)₄], (η-C₅H₅)₂Co₂[C₂H ₂(CF₃)]₂, and (η-C₅H₅)Co[C₄(C₆H ₅)₄]; (2) multimetal clusters containing cyclopentadienylcobalt units and alkynes, i.e., (η-C₅H₅)₃Co₃[C ₂(CF₃)₂], (η-C₅H₅)₃Co₃[C ₂(CF₃)₂](μ₃-CO), and [η-C₅(CH₃)₅]₂Co ₂[C₂(CF₃)₂]₂; (3) complexes containing ligands resulting from cycloadditions of cyclopentadiene and alkynes, i.e., (η-C₅H₅)Co[C₇H₆(CF ₃)₂] and (η-C₅H₅)Co[C₉H₆(CF ₃)₄]; (4) complexes containing ligands resulting from simple additions of cyclopentadiene and alkynes, i.e., (η-C₅H₅)₂Co₂[C₇H ₈(CF₃)₂], (η-C₅H₅)₂Co₂[C₉H ₄(CF₃)₄], (η-C₅H₅)₂Co₂[C₉H ₆(CF₃)₄], and (η-C₅H₅)Co[C₉H₆(C ₆H₅)₄]. The nature of these products implies the formation of certain reactive cyclopentadienylcobalt intermediates in these metal atom reactions, and an appropriate reaction scheme is discussed.