title: Reactivity of the terminal oxo species (((t)Bu2PCH2SiMe2)2N)RhO.
abstract: Reactivity of the 4-coordinate molecule (PNP)RhO (PNP is ((t)Bu2PCH2SiMe2)2N) towards CO proceeds stepwise, first forming an η(2)-CO2 complex, by a mechanism which involves a preliminary adduct of CO on Rh, then a second CO displaces CO2. Reaction of the oxo complex with CO2 occurs in time of mixing even at low temperature to form (PNP)Rh(η(2)-CO3), with no intermediate detectable. DFT calculations indicate an initial bond formation between the oxo center and the CO2 carbon. Reaction of (PNP)RhO with H2 occurs only at a 1 : 2 molar stoichiometry, to ultimately form (PNP)Rh(H)2 and free H2O. No intermediate reaches detectable population even at -60 °C, but DFT mapping of various possible mechanisms on the singlet energy surface shows that the nearly equi-energetic (PNP)Rh(H2O) and (PNP)RhH(OH) are formed, but only the latter readily adds the second molecule of H2 to proceed to the observed products; these reactions thus both involve heterolytic splitting of H2.
authors.affiliation: Indiana University, Department of Chemistry, 800 East Kirkwood Avenue, Bloomington, Indiana, USA.
authors.forename: Nikolay P
authors.initials: NP
authors.lastname: Tsvetkov
authors.forename: José G
authors.initials: JG
authors.lastname: Andino
authors.forename: Hongjun
authors.initials: H
authors.lastname: Fan
authors.forename: Alexander Y
authors.initials: AY
authors.lastname: Verat
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Caulton