Abstract
Cobalt fluorocarbene complex CpCo(CF(CF3))(PPh2Me) (Cp = η5-cyclopentadienyl) reacts with para-substituted phenylacetylenes to furnish partially fluorinated cobaltacyclobutene complexes [Cp(PPh2Me)Co{κ2-C(Ar)CHCF(CF3)}], which were isolated and characterized by elemental analysis, multinuclear NMR and UV–vis spectroscopy, and X-ray crystallography. The scope of reactivity between CpCo(CFRF)(L) and various alkynes was explored. The detailed pathway for the [2 + 2] cycloaddition reaction was investigated using a combination of kinetic studies and DFT computational chemistry (M06/def2-TZVP), with a 1,4 diradical species identified as the key intermediate.