Transition metal complexes of substituted alkynes. VI. Substituent arrangement in some bridging tris(alkyne)-cobalt complexes

Abstract

The new organocobalt complex CO₂(CO)₄(CF₃C₂CF₃)₂(CF₃C₂H) has been isolated from the reaction of hexafluorobut-2-yne with p-trifluoropropyne-hexacarbonyldicobalt. In addition, a second isomer of the known complex CO₂(CO)₄(CF₃C₂CF₃)₂(CF₃C₂H)₂ has been isolated from the reaction of 3,3,3-tri-fluoropropyne with p-hexafluorobut-2-yne-hexacarbonyldicobalt. A detailed study of the ¹H and ¹⁹F N.M.R. spectra of these and the related complexes Co₂(C0)_4- (CF₃C₂CF₃)₃ and CO₂(CO)₄₍CF₃C₂H)₃ has led to an assignment of the substituent arrangement in all of these complexes.