TRIFLUOROMETHYL, DIFLUOROCARBENE AND TETRAFLUOROETHYLENE COMPLEXES OF IRIDIUM AND THE CRYSTAL-STRUCTURES OF IRI(CH3)(CF3)(CO)(PPH3)2, IR(CF3)(C2F4)(CO)(PPH3)2 AND IR(CF3)(=CF2)(CO)(PPH3)2

A trifluoromethyl iridium(I) complex Ir(CF3)(CO)2(PPh3)2 (1 has been prepared by the reaction of Hg(CF3)2 with IrH(CO)2(PPh3)2, or by thermal decomposition of Ir(COCF3)(CO)2(PPh3)2 (3), which is produced from (CF3CO)2O and a reduced iridium(-I) species. Either the reaction of IrH(CO)(PPh3)3 with Hg(CF3)2 or the reversible thermal decarbonylation of 1 yields the coordinatively unsaturated complex Ir(CF3)(CO)(PPh3)2 (2). Derivatives Ir(CF3)L(CO)(PPh3)2 (L = C2F4 (4), L = C2H4 (5), L = O2 (6)) result from treatment of 1 with tetrafluoroethylene, or 2 with ethylene or oxygen, respectively. Both 1 and 2 undergo oxidative addition of Cl2, I2, HCl, H2 and CH3I to give trifluoromethyl iridium(III) complexes IrCl2(CF3)(CO)(PPh3)2 (7), IrI2 (CF3)(CO)(PPh3)2 (8), IrHCl(CF3)(CO)(PPh3)2 (9), cis-IrH2(CF3)(CO)(PPh3)2 (10) and IrI(CH3)(CF3)(CO)(PPh3)2 (11), respectively. The iodo ligand in 11 is labile and can be replaced by an acetonitrile ligand to yield [Ir(CH3)(CF3)(L)(CO)(PPh3)2] ClO4 (L = CH3CN (12)). This ligand can in turn be replaced by p-tolylisocyanide (L = CN-p-C6H4CH3 (13)) or Cl- to give IrCl(CH3)(CF3)(CO)(PPh3)2 (14). Complexes 1 and 9 each react with AlCl3 to give the difluoromethyl species IrCl2(CF2H)(CO)(PPh3)2 (15). A difluorocarbene iridium(I) complex, IrCl(CF2)(CO)(PPh3)2 (16), has been prepared by thermal decarbonylation of Ir(COCF2Cl)(CO)2(PPh3)2 (18), and a complex containing both CF3 and CF2 ligands, Ir(CF2)(CF3)(CO)(PPh3)2 (17), has been made by treatment of either IrCl(CO)(PPh3)2, 2 or 16 with Cd(CF3)2 · glyme. Both 16 and 17 are hydrolysed to give carbonyl species IrCl(CO)2(PPh3)2 and 1, respectively, while 16 reacts with t-butylamine to give an isocyanide complex, IrCl(CN-t-C4H9)(CO)(PPh3)2 (20). Addition of HCl to 16 or 17 produces 15 or 9, respectively. Complexes 4, 11 and 17 have been characterised by X-ray diffraction studies. © 1990.