title: Enantiospecific desorption of R- and S-propylene oxide from D- or L-lysine modified Cu(100) surfaces.
abstract: The enantiospecific desorption kinetics of R- and S-propylene oxide (PO) from a Cu(100) surface modified by enantiomerically pure D- or L-lysine have been studied using temperature programmed desorption. These experiments have used R- or S-PO as the chiral probe for study of enantiospecific adsorption on Cu(100) surfaces modified with D- or L-lysine. This chiral probe/modifier/Cu system manifests a significant diastereomeric effect in the R- and S-PO peak desorption temperatures and, hence, true enantiospecific behavior. The enantiospecificity in the PO desorption kinetics is observed only over a narrow range of lysine modifier coverage with a maximum at a lysine coverage leaving an empty site density of θ(O) ≈ 0.25. The observation of enantiospecific behavior in the PO/lysine/Cu(100) system is in contrast with the failed results of prior attempts to observe enantiospecific desorption from chirally modified Cu surfaces. The potential for hydrogen-bonding interactions between the chiral probe and chiral modifier, which can depend on the coverage and configuration of the adsorbed modifier, may play a crucial role in enantiospecific adsorption on lysine modified Cu surfaces.
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Wai Yeng
authors.initials: WY
authors.lastname: Cheong
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gellman
mesh_terms: D000327:Adsorption; D003300:Copper / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D008239:Lysine / Q000737:chemistry*; D013057:Spectrum Analysis; D013237:Stereoisomerism; D013499:Surface Properties; D013696:Temperature
chemical_list: D004852:Epoxy Compounds; D003300:Copper; D008239:Lysine; C009068:propylene oxide