title: Scanning Tunneling Microscopy Measurements of the Full Cycle of a Heterogeneous Asymmetric Hydrogenation Reaction on Chirally Modified Pt(111).
abstract: The hydrogenation of a prochiral substrate, 2,2,2-trifluoroacetophenone (TFAP), on Pt(111) was studied using room-temperature scanning tunneling microscopy (STM) measurements. The experiments were carried out both on a clean surface and on a chirally modified surface, using chemisorbed (R)-(+)-1-(1-naphthyl)ethylamine, ((R)-NEA), as the modifier. On the nonmodified surface, introduction of H2 at a background pressure of ∼1 × 10(-6) mbar leads to the rapid break-up of TFAP dimer structures followed by the gradual removal of all TFAP-related images. During the latter step, some monomers display an extra protrusion compared to TFAP in dimer structures. They are attributed to a half-hydrogenated intermediate. The introduction of H2 to a mixture of (R)-NEA and TFAP on Pt(111) leads to the removal of TFAP without any change in the population of the modifier, as required for an efficient chirally modified catalyst.
authors.affiliation: CERPIC et Département de chimie, Université Laval , Québec, Qc, Canada G1V 0A6.
authors.forename: Vincent
authors.initials: V
authors.lastname: Demers-Carpentier
authors.affiliation: CERPIC et Département de chimie, Université Laval , Québec, Qc, Canada G1V 0A6.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Goubert
authors.affiliation: CERPIC et Département de chimie, Université Laval , Québec, Qc, Canada G1V 0A6.
authors.forename: Federico
authors.initials: F
authors.lastname: Masini
authors.affiliation: CERPIC et Département de chimie, Université Laval , Québec, Qc, Canada G1V 0A6.
authors.forename: Yi
authors.initials: Y
authors.lastname: Dong
authors.affiliation: iNANO and Department of Physics and Astronomy, Aarhus University , 8000 Aarhus C, Denmark.
authors.forename: Anton M H
authors.initials: AM
authors.lastname: Rasmussen
authors.affiliation: iNANO and Department of Physics and Astronomy, Aarhus University , 8000 Aarhus C, Denmark.
authors.forename: Bjørk
authors.initials: B
authors.lastname: Hammer
authors.affiliation: CERPIC et Département de chimie, Université Laval , Québec, Qc, Canada G1V 0A6.
authors.forename: Peter H
authors.initials: PH
authors.lastname: McBreen
keywords: asymmetric heterogeneous catalysis; chirally modified surfaces