Abstract

Reported here are the in situ FT-IR and 13C-NMR spectroscopic studies of the complex cis-[Ir(CO) 2(py) 2](PF 6) (py = pyridine) dissolved in 80% aqueous pyridine used as a precursor in the homogeneous catalysis of the water gas shift reaction (WGSR, CO + H 2O ? CO 2 + H 2). These spectroscopy studies reveal the presence of aminocarbonyliridium complexes with linear and bridging carbonyls groups as reaction intermediates. The WGSR catalysis by Ir 4(CO) 12 complex dissolved in 80% of aqueous 4-picoline or pyridine under 1.9 atm of CO at 100°C and the FT-IR and 1H-NMR in situ studies of the pyridine promoted disproportionation of Ir 4(CO) 12, are also described.