TETRAFLUOROETHYL COMPLEXES OF IRIDIUM(III) DERIVED FROM A TETRAFLUOROETHYLENE COMPLEX OF IRIDIUM(I) - A STUDY OF ALPHA-FLUORIDE ABSTRACTION AND DETERMINATION OF THE STRUCTURE OF IRCL2(CF2CF2CL)(CO)(PPH(3))(2)

Treatment of the tetrafluoroethylene complex, IrCl(eta(2)-C2F4)(PPh(3))(2), (1), with HCl or Cl-2 gives IrCl2(CF2CF2H)(PPh(3))(2) (2) or IrCl2(CF2CF2Cl)(PPh(3))(2) (3), respectively. These coordinately unsaturated complexes react with Various neutral ligands to give stable, six-coordinate, tetrafluoroethyl and halotetrafluoroethyl complexes. The single crystal X-ray structure of one of these compounds, the carbonyl derivative of (3), IrCl2(CF2CF2Cl)(CO)(PPh(3))(2) (15) was determined. The acetonitrile derivative of (2), IrCl2(CF2CF2H)(CH3CN)(PPh(3))(2) (17) undergoes a reaction with HCl that proceeds through the intermediate fluorocarbene complex, [IrCl2(=CFCF2H)(CH3CN)(PPh(3))](+) (18), to give, upon hydrolysis, IrCl2(C[O]CF2H)(CH3CN)(PPh(3))(2) (19). The acetonitrile ligand, by virtue of its position trans to the acyl group, can be thermally displaced from (19) to give IrCl2(C[O]CF2H)(PPh(3))(2) (20). The vacant coordination site in (20) can be filled by other neutral ligands. Thermal treatment of any of the acyl complexes results finally in a reverse migration process and formation of IrCl2(CF2H)(CO)(PPh(3))(2) (23).