title: A combined parahydrogen and theoretical study of H2 activation by 16-electron d8 ruthenium(0) complexes and their subsequent catalytic behaviour.
abstract: The photochemical reaction of Ru(CO)(3)(L)(2), where L = PPh(3), PMe(3), PCy(3) and P(p-tolyl)(3) with parahydrogen (p-H(2)) has been studied by in-situ NMR spectroscopy and shown to result in two competing processes. The first of these involves loss of CO and results in the formation of the cis-cis-trans-L isomer of Ru(CO)(2)(L)(2)(H)(2), while in the second, a single photon induces loss of both CO and L and leads to the formation of cis-cis-cis Ru(CO)(2)(L)(2)(H)(2) and Ru(CO)(2)(L)(solvent)(H)(2) where solvent = toluene, THF and pyridine (py). In the case of L = PPh(3), cis-cis-trans-L Ru(CO)(2)(L)(2)(H)(2) is shown to be an effective hydrogenation catalyst with rate limiting phosphine dissociation proceeding at a rate of 2.2 s(-1) in pyridine at 355 K. Theoretical calculations and experimental observations show that H(2) addition to the Ru(CO)(2)(L)(2) proceeds to form cis-cis-trans-L Ru(CO)(2)(L)(2)(H)(2) as the major product via addition over the pi-accepting OC-Ru-CO axis.
authors.affiliation: Department of Chemistry, University of York, UK.
authors.forename: John P
authors.initials: JP
authors.lastname: Dunne
authors.forename: Damir
authors.initials: D
authors.lastname: Blazina
authors.forename: Stuart
authors.initials: S
authors.lastname: Aiken
authors.forename: Hilary A
authors.initials: HA
authors.lastname: Carteret
authors.forename: Simon B
authors.initials: SB
authors.lastname: Duckett
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Jones
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Poli
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Whitwood