Mechanism of Carbon−Fluorine Bond Activation by (C5Me5)Rh(PMe3)H2

The complex Cp*Rh(PMe 3 )H 2 (Cp* = C 5 Me 5 ) reacts with C 6 F 6, C 6 F 5 H, C 12 F 10, or C 10 F 8 in pyridine or 1:1 pyridine/benzene to give the C−F cleavage products Cp*Rh(PMe 3 )(aryl F )H in high yield. Kinetic studies reveal that the reaction has autocatalytic character, and fluoride ion is shown to be responsible for the catalysis. The anion [Cp*Rh(PMe 3 )H] - reacts rapidly with C 12 F 10 or C 10 F 8 to give the same C−F cleavage products as Cp*Rh(PMe 3 )H 2 . A mechanism initiated by deprotonation of Cp*Rh(PMe 3 )H 2 followed by nucleophilic attack of the resulting anion on the polyfluoroaromatic with subsequent loss of fluoride is proposed. The fluoride ion continues the cycle by deprotonating Cp*Rh(PMe 3 )H 2 .