Synthesis and structural characterization of (perfluoroalkyl)fluoroiridium(III) and (perfluoroalkyl)methyliridium(III) compounds

A new family of metal perfluoroalkyl fluoro compounds has been obtained by treatment of the iodo precursors Cp* Ir(PMe3)(R-F) I with AgF in CH2Cl2 solution in the dark to give Cp* Ir(PMe3)(R-F) F (R-F = CF3, CF2CF3, CF2CF2CF3, CF(CF3)(2), CF(CF3)(CF2CF3)). The molecular structures of the compounds with RF) CF2CF3, CF2CF2CF3, CF(CF3)(2) have been determined crystallographically. These fluoro compounds provide a ready and reproducible route to the analogous methyl complexes Cp* Ir( PMe3)( R-F) CH3, by treatment with exactly 0.5 equiv of Zn(CH3)(2) at low temperatures in toluene. Alkylation with other reagents such as CH3Li and Cp2Zr(CH3)(2) leads to inseparable mixtures. This metathesis of Ir-F and Zn-CH3 represents the only way to date for the clean reproducible synthesis of Cp* Ir(PMe3)( R-F) CH3 compounds containing primary perfluoroalkyl groups. The molecular structures of Cp* Ir(PMe3)( R-F) CH3 (R-F = CF2CF3, CF2CF2CF3) have been determined crystallographically.