Synthesis and Structural Characterization of (Perfluoroalkyl)fluoroiridium(III) and (Perfluoroalkyl)methyliridium(III) Compounds

Abstract

A new family of metal perfluoroalkyl fluoro compounds has been obtained by treatment of the iodo precursors Cp*Ir(PMe3)(RF)I with AgF in CH2Cl2 solution in the dark to give Cp*Ir(PMe3)(RF)F (RF = 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)(RF)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)(RF)CH3 compounds containing primary perfluoroalkyl groups. The molecular structures of Cp*Ir(PMe3)(RF)CH3 (RF = CF2CF3, CF2CF2CF3) have been determined crystallographically.