Mechanistic studies of the activation and the decomposition of [Rh2Cl2(CO)4] in organometallic chemical vapour deposition

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