CARBONYLATION OF TRANS-IR(CO)CL(TPPTS)(2) AND REACTIVITY OF [IR(CO)(2)(TPPTS)(3)]CL (TPPTS = P(M-C6H4SO3NA)(3)) IN DMSO AND WATER

Reaction of CO with trans-Ir(CO)(Cl)(TPPTS)(2) in DMSO and H2O give [I r(CO)(3)(TPPTS)(2)]-Cl (H2O and DMSO) and Ir(CO)(2)(Cl)(TPPTS)(2) (DMS O only). In both solvents the carbonylation is reversed. by passing N- 2 through the solution. In water, further reactions occur slowly, incl uding water-gas-shift reactions and formation of Ir(CO)(2)(TPPTS)(3)(). This trisphosphine complex was independently prepared to examine it s reactions. In DMSO, reaction with CO readily forms Ir(CO)(3)(TPPTS)( 2)(+); no reaction with CO is observed in water. Reaction of Ir(CO)(2) (TPPTS)(3)(+) with H-2 occurs through TPPTS dissociation giving Ir(CO) (2)- (H)(2)(TPPTS)(2)(+) initially before reaction with free TPPTS giv es Ir(CO)(H)(2)(TPPTS)(3)(+) as the final product. Hydrogen bonding fr om water to the sulfonated phosphine ligands provides a reasonable exp lanation for the differing ligand substitution behavior in DMSO and H2 O.