Reactions of SO2 with trans-Ir(CO)(Cl)(TPPTS)(2) in water

Reaction of SO2 with trans-Ir(CO)(Cl)(TPPTS)(2) in water mirrors the nature of SO2 dissolved in water. At low pH (pH = 1) where SO2 exists as the hydr ated species SO2.H2O, only Ir(CO)(Cl)(SO2)(TPPTS)(2) forms. At higher pH (p H = 6) where HSO3- dominates, no SO2 complex is observed and a hydride, Ir( CO)(Cl)(H)(OH)(TPPTS)(2), is the primary product. A mixture of SO2 and O-2 does not lead to an iridium sulfate or show any evidence of the dioxygen ad duct upon reaction in water with trans-Ir(CO)(Cl)(TPPTS)(2), in contrast to the analogous reaction in organic solvents. In water, only the SO2 complex , Ir(CO)(Cl)(SO2)(TPPTS)(2), is observed prior to decomposition. The contra sts to the PPh3 analogues in organic solvents provide further insight to wa ter as a solvent for organometallic complexes.