title: Stereodirection of an α-ketoester at sub-molecular sites on chirally modified Pt(111): heterogeneous asymmetric catalysis.
abstract: Chirally modified Pt catalysts are used in the heterogeneous asymmetric hydrogenation of α-ketoesters. Stereoinduction is believed to occur through the formation of chemisorbed modifier-substrate complexes. In this study, the formation of diastereomeric complexes by coadsorbed methyl 3,3,3-trifluoropyruvate, MTFP, and (R)-(+)-1-(1-naphthyl)ethylamine, (R)-NEA, on Pt(111) was studied using scanning tunneling microscopy and density functional theory methods. Individual complexes were imaged with sub-molecular resolution at 260 K and at room temperature. The calculations find that the most stable complex isolated in room-temperature experiments is formed by the minority rotamer of (R)-NEA and pro-S MTFP. The stereodirecting forces in this complex are identified as a combination of site-specific chemisorption of MTFP and multiple non-covalent attractive interactions between the carbonyl groups of MTFP and the amine and aromatic groups of (R)-NEA.
authors.affiliation: C3V and Department of Chemistry, Laval University, Québec, Canada G1V 0A6.
authors.forename: Vincent
authors.initials: V
authors.lastname: Demers-Carpentier
authors.forename: Anton M H
authors.initials: AM
authors.lastname: Rasmussen
authors.forename: Guillaume
authors.initials: G
authors.lastname: Goubert
authors.forename: Lara
authors.initials: L
authors.lastname: Ferrighi
authors.forename: Yi
authors.initials: Y
authors.lastname: Dong
authors.forename: Jean-Christian
authors.initials: JC
authors.lastname: Lemay
authors.forename: Federico
authors.initials: F
authors.lastname: Masini
authors.forename: Yang
authors.initials: Y
authors.lastname: Zeng
authors.forename: Bjørk
authors.initials: B
authors.lastname: Hammer
authors.forename: Peter H
authors.initials: PH
authors.lastname: McBreen
mesh_terms: D002384:Catalysis; D004952:Esters / Q000737:chemistry*; D006865:Hydrogenation; D010984:Platinum / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D004952:Esters; D010984:Platinum