Activation of molecular hydrogen by cationic iridium diene complexes

Abstract
The cationic complexes [Ir(cod)L2]PF6(1; L = tertiary phosphine; cod = cyclo-octadiene) react with dihydrogen at –80 °C in CD2Cl2 to give cis-[IrH2(cod)L2]PF6 complexes which revert to (1) on warming; at 0 °C in CH2Cl2 complex (1; L = PMePh2) is a highly active hydrogenation catalyst.