Reversible CO2 Fixation by Iridium(I) Complexes Containing Me2PhP as Ligand

The iridium(I) complexes [IrCl(Me2PhP)(3)] (1), [Ir(Me7PhP)(4)]Cl (2), [Ir(Me2PhP)(4)]I (3), and [Ir(Me-2-PhP)(4)]PF6 (4) are prepared from the iridium(I) precursors [IrX(coe)(2)](2) (X = Cl, I). Complex 1 reacts reversibly with CO2 to form the metallacyclic compound [IrCl(C2O4-kappa C-2,O)(Me2PhP)(3)] (5), which was characterized by NMR and IR measurements as well as elemental analysis. Additionally, [mer-Ir(Cl)(2)(H)(Me,PhP)(3)] (6) and [mer-Ir(CO3)(H)(Me2PhP)(3)] (7) are formed as side products from water present in the used CO2 and the solvents. Compound 2 yields similar results. When the iodo compound 3 is used, the cationic compound [Ir(I)(H)(Me2PhP)(4)]I-+(-) (9) is formed as one of the products. Molecular structures of 1, 2, 5, and 9 are presented.