Trifluoromethyl, difluorocarbene and tetrafluoroethylene complexes of iridium and the crystal structures of IrI(CH 3)(CF 3)(CO)(PPh 3) 2, Ir(CF 3)(C 2F 4)(CO)(PPh 3) 2 and Ir(CF 3)(CF 2)(CO)(PPh 3) 2

Abstract

A trifluoromethyl iridium(I) complex Ir(CF 3)(CO) 2(PPh 3) 2 ( 1 has been prepared by the reaction of Hg(CF 3) 2 with IrH(CO) 2(PPh 3) 2, or by thermal decomposition of Ir(COCF 3)(CO) 2(PPh 3) 2 ( 3), which is produced from (CF 3CO) 2O and a reduced iridium(−I) species. Either the reaction of IrH(CO)(PPh 3) 3 with Hg(CF 3) 2 or the reversible thermal decarbonylation of 1 yields the coordinatively unsaturated complex Ir(CF 3)(CO)(PPh 3) 2 ( 2). Derivatives Ir(CF 3)L(CO)(PPh 3) 2 (L = C 2F 4 ( 4), L = C 2H 4 ( 5), L = O 2 ( 6)) result from treatment of 1 with tetrafluoroethylene, or 2 with ethylene or oxygen, respectively. Both 1 and 2 undergo oxidative addition of Cl 2, I 2, HCl, H 2 and CH 3I to give trifluoromethyl iridium(III) complexes IrCl 2(CF 3)(CO)(PPh 3) 2 ( 7), IrI 2 (CF 3)(CO)(PPh 3) 2 ( 8), IrHCl(CF 3)(CO)(PPh 3) 2 ( 9), cis-IrH 2(CF 3)(CO)(PPh 3) 2 ( 10) and IrI(CH 3)(CF 3)(CO)(PPh 3) 2 ( 11), respectively. The iodo ligand in 11 is labile and can be replaced by an acetonitrile ligand to yield [Ir(CH 3)(CF 3)(L)(CO)(PPh 3) 2]ClO 4 (L = CH 3CN ( 12)). This ligand can in turn be replaced by p-tolylisocyanide (L = CN- p-C 6H 4CH 3 ( 13)) or Cl − to give IrCl(CH 3)(CF 3)(CO)(PPh 3) 2 ( 14). Complexes 1 and 9 each react with AlCl 3 to give the difluoromethyl species IrCl 2(CF 2H)(CO)(PPh 3) 2 ( 15). A difluorocarbene iridium(I) complex, IrCl(CF 2)(CO)(PPh 3) 2 ( 16), has been prepared by thermal decarbonylation of Ir(COCF 2Cl)(CO) 2(PPh 3) 2 ( 18), and a complex containing both CF 3 and CF 2 ligands, Ir(CF 2)(CF 3)(CO)(PPh 3) 2 ( 17), has been made by treatment of either IrCl(CO)(PPh 3) 2, 2 or 16 with Cd(CF 3) 2 · glyme. Both 16 and 17 are hydrolysed to give carbonyl species IrCl(CO) 2(PPh 3) 2 and 1, respectively, while 16 reacts with t-butylamine to give an isocyanide complex, IrCl(CN-t-C 4H 9)(CO)(PPh 3) 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.