Transition metal complexes of substituted alkynes. II. Pentafluorophenylacetylene complexes of iron and cobalt

Abstract

Treatment of pentacarbonyliron with pentafluorophenylacetylene has given the stable complex tricarbonyl-2,5-bis(pentafluorophenyl)cyclopentadienoneiron. There is no evidence of the formation of other structural isomers. The complex is also formed from pentafluorophenylaoetylene and nonacarbonyldiiron or dodecacarbonyltriiron. Two alkyne-cobalt complexes have been isolated from the interaction of octacarbonyldicobalt and pentafluorophenylacetylene. One of these is a bridging alkyne complex of molecular stoicheiometry Co₂(CO)₆(C₆F₆CCH); the second is a complex of formula Co₃(CO)₉(CCH₂C₆F₅). The infrared and nuclear magnetic resonance spectra of the complexes are given, and the probable structures of the compounds are deduced from these spectroscopic properties.