Complexes derived from the reactions of diphenylphosphinoacetic acid. Part 4. Mononuclear complexes of Rh(I), Ir(I) and Ir(III) and some related chemistry involving the diphenyl(2,6-dimethylphenyl)-phosphine ligand

The iridium complex [IrCl(COD)](2) reacts with diphenylphosphinoacetic acid (1) in the Presence of CO to afford the iridium(III) complex IrHCl(CO)(eta(2)-Ph2PCH2CO2)eta(1)-Ph2PCH2CO2H) (3) which in the solid state exists as a hydrogen-bonded dimer. Complex 3 converts to IrH(CO)(eta(2)-Ph2PCH2CO2)(2) (4) when treated with AgO3SCF3 in dichloromethane. The tertiary phosphine PPh2(Ph-2,6-Me-2) (2) reacts with solutions of [RhCl(CO)(2)](2) and [IrCl(COD)](2) (in the presence of CO) in dichloromethane to give the square planar complexes MCl(CO)[PPh2(Ph-2,6-Me-2)](2) (M = Rh (5) or Ir (6) in high yield. While the iridium(I) complex 6 undergoes an oxidative-addition reaction with HgCl2 to yield the complex IrCl2(HgCl)(CO)[PPh2(Ph-2,6-Me-2)](2) (7), complex 5 is unreactive towards this reagent. (C) 2002 Elsevier Science B.V. All rights reserved.