While fluorine forms the strongest single bond to carbon, it is well established that transition metals can lengthen and weaken ligated C-F bonds. Described here are studies on the activation of C-F bonds on iridium (III) compounds induced by acids and reducing agents.

New methods towards the preparation of Cp*Ir(PMe₃)(R _F)(R) (R = Me, Ph) compounds using ZnR₂ (R = Me, Ph) are reviewed and extended to the secondary butyl compound, Cp*Ir(PMe₃)[CF(CF ₃)(CF₂CF₃)](Me). X-ray crystallographic and variable temperature NMR studies were performed on Cp*Ir(PMe₃)[CF(CF ₃)(CF₂CF₃)](H) and Cp*Ir(PMe₃)(CF ₂CF₂CF₃)(Ph) in an effort to determine the ground state conformation and the origin of restricted rotation about some of the bonds.

Oxidative addition of I-CF₂CF₂CF₃ to CpIr(CO)(PMe₃) gave a mixture of four major products: [CpIr(CO)(PMe ₃)(CF₂CF₂CF₃)]I, CpIr(PMe₃)(CF ₂CF₂CF₃)(I), CpIr(PMe₃)(COCF₂ CF₂CF₃)(I), and CpIr(PMe₃)(COCF ₂CF₂CF₃)(CF₂CF₂CF₃ ). A mechanism to the formation of these compounds has been proposed beginning with a single electron transfer from CpIr(CO)(PMe₃) to I-CF₂CF₂CF₃.

A novel class of perfluoroalkylidene compounds, (C₅R ₅)Ir(L)(=CFR_F) (R = H, Me; L = CO, PMe₃; R _F = F, CF₃, CF₂CF₃) has been prepared by reduction of the corresponding (perfluoroalkyl)(iodide) compounds, (C ₅R₅)Ir(L)(CF₂R_F)(I), with potassium or magnesium graphite. HCl addition to the iridium carbon double bond is shown to occur in a regio- and stereospecific cis fashion to yield (C₅Me ₅)Ir(L)(CFHR_F)(Cl).

Iridium fluoroolefin compounds of the class, Cp*Ir(L)(CH₂=CFR _F) (L = CO, PMe₃; R_F = F, CF₃, CF ₂CF₃), have been prepared by the reduction of Cp*Ir(L)(CH ₂CF₂R_F)(I) with potassium or magnesium graphite. Addition of HCl resulted in formation of the methyl compounds, Cp*Ir(L)[CF(CH ₃)(R_F)](Cl), from a regio- and stereospecific addition of HCl. Addition of acids with more weakly coordinating anions (HOTf, HO ₂CCF₃) ultimately formed the rearranged product, Cp*Ir(L)(CH ₂CHFR_F)(X), which resulted from a β-hydride elimination from the methyl group.

The reaction of HX in ether with Cp*Ir(PMe₃)[CF(CF₃)(CF ₂R_F)](H) (R_F = F, CF₃) yielded Cp*Ir(PMe ₃)[CH(CF₃)(CF₂R_F)](Cl) and Cp*Ir(PMe ₃)[CF(CF₃)(CF₂R_F)](Cl) while the same reaction in toluene resulted in Cp*Ir(PMe₃)(X)₂ and CF₃CH₂CF₂R_F. However, no reaction of Cp*Ir(PMe₃)[CF(CF₃)(CF₂R_F)](Me) was observed with HX in toluene or ether.