title: Understanding the role of water in aqueous ruthenium-catalyzed transfer hydrogenation of ketones.
abstract: We report an accurate computational study of the role of water in transfer hydrogenation of formaldehyde with a ruthenium-based catalyst using a water-specific model. Our results suggest that the reaction mechanism in aqueous solution is significantly different from that in the gas phase or in methanol solution. Previous theoretical studies have shown a concerted hydride and proton transfer in the gas phase (M. Yamakawa, H. Ito, R. Noyori, J. Am. Chem. Soc. 2000, 122, 1466-1478;J.-W. Handgraaf, J. N. H. Reek, E. J. Meijer, Organometallics 2003, 22, 3150-3157; D. A. Alonso, P. Brandt, S. J. M. Nordin, P. G. Andersson, J. Am. Chem. Soc. 1999, 121, 9580-9588; D. G. I. Petra, J. N. H. Reek, J.-W. Handgraaf, E. J. Meijer, P. Dierkes, P. C. J. Kamer, J. Brussee, H. E. Schoemaker, P. W. N. M. van Leeuwen, Chem. Eur. J. 2000, 6, 2818-2829), whereas a delayed, solvent-mediated proton transfer has been observed in methanol solution (J.-W. Handgraaf, E. J. Meijer, J. Am. Chem. Soc. 2007, 129, 3099-3103). In aqueous solution, a concerted transition state is observed, as in the previous studies. However, only the hydride is transferred at that point, whereas the proton is transferred later by a water molecule instead of the catalyst.
authors.affiliation: Van't Hoffs Institute of Molecular Sciences, University Of Amsterdam, Netherlands.
authors.forename: Anna
authors.initials: A
authors.lastname: Pavlova
authors.forename: Evert Jan
authors.initials: EJ
authors.lastname: Meijer
mesh_terms: D002384:Catalysis; D006865:Hydrogenation; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D012428:Ruthenium / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D007659:Ketones; D012996:Solutions; D014867:Water; D012428:Ruthenium