REACTIONS OF CARBON MONOXIDE WITH trans-Ir(CO)(Cl)(TPPMS)2 (TPPMS = PPh2(C6H4SO3K)) IN DMSO AND WATER, RATE AND MECHANISTIC STUDIES

Abstract

Reaction of CO with trans-Ir(CO)(Cl)L2 (L = PPh3 in toluene and DMSO; L = TPPMS in DMSO and H2O, TPPMS = PPh2(m-C6H4SO3Na)) reversibly produces Ir(CO)2(Cl)L2 or [Ir(CO)3L2]Cl depending on the solvent polarity. The solvent polarity has a small effect on the rate of reaction with CO; the rate constants in toluene, DMSO and H2O are all within a factor of two. Comparison to the reaction with H2 shows that the selectivity for CO is much greater (k CO/k H2 = 150) in toluene than in water (k CO/k H2 = 5).