Analysis of the synergistic effect of carbonylplatinum complexes on the iridium-catalysed carbonylation of methanol to acetic acid

High-pressure NMR mechanistic investigations into the promoting role of dicarbonyldiiodoplatinum complex in the iridium-catalysed carbonylation of methanol to acetic acid are consistent with iodide abstraction from the [IrI3(CH3)(CO)(2)](-)resting state species by [PtI2(CO)(2)], unbolting the rate-limiting migratory CO insertion step. A new [Ir-Pt] heterodimetallic complex, which presumably represents the key species involved in the abstraction of I-, has been characterised by NMR in tandem with FAB-MS. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)