MECHANISTIC STUDIES OF THE ACTIVATION AND THE DECOMPOSITION OF [RH2CL2(CO)(4)] IN ORGANOMETALLIC CHEMICAL-VAPOR-DEPOSITION

Various direct and indirect methods have been investigated to show tha t hydride-rhodium species are generated in the gas phase when vapours of [Rh2Cl2(CO)(4)] react with dihydrogen for the organometallic chemic al vapour deposition of rhodium on silica supports. Mass spectrometric , infrared, and thermogravimetric analyses were carried out to identif y the activated species which are produced in the gas phase. Addition of [AuPPh(3)I] which is an isolobal analogue of HCl to [Rh2Cl2(CO)(4)] was examined to simulate the presence of an hydride intermediate and to show the role of dihydrogen. The isolation of [Rh-2(mu-Cl)(mu-I)(CO )(3)(PPh(3))], whose X-ray crystal structure was determined, also supp orts a primary oxidative addition of H-2 to [Rh2Cl2(CO)(4)].