Formation of Tetrafluorobenzyne by β-Fluoride Elimination in Zirconium-Perfluorophenyl Complexes

Cp*2ZrH2 (Cp* = pentamethylcyclopentadienyl) and Hg(C6F5)2 react in pentane to form Cp*2Zr(C6F5)H in high yield at room temperature. Cp*2Zr(C6F5)H reacts intramolecularly at 120 °C under an atmosphere of H2 to give Cp*2Zr(o-C6F4H)F quantitatively by β-fluoride elimination and subsequent insertion of tetrafluorobenzyne into the Zr−H bond. Under vacuum, Cp*2Zr(C6F5)H decomposes into a mixture of Cp*2Zr(o-C6F4H)F and the ring methyl C−H activated product, Cp*(Fv)Zr(C6F5) (Fv = tetramethylfulvene). Upon further heating, Cp*(Fv)Zr(C6F5) reacts to form the novel complex Cp*(C5Me4CH2(C6F4))ZrF, formed by β-fluoride elimination and subsequent insertion of tetrafluorobenzyne into the Zr−CH2 bond.