AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuM

Paper SS1-TuM8
Enantioselective Reactivity of R-2-bromobutane on Cu(531)

Tuesday, November 4, 2003, 10:40 am, Room 327

Session: Catalysis II: Hydrocarbons at Metal Surfaces
Presenter: D.M. Rampulla, Carnegie Mellon University
Authors: D.M. Rampulla, Carnegie Mellon University
A.J. Gellman, Carnegie Mellon University
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Enantioselective reactions are integral to most biological chemistry and large-scale pharmaceutical production. The difficult aspect of enantioselective reactions is that they require chiral media such as solvents, surfaces, or catalysts. Enantioselective heterogeneous catalysis is a promising method for the preparation of chiral compounds but requires catalytic surfaces with inherently chiral structure. The stepped and kinked high Miller index surfaces of metals are naturally chiral and have been shown to interact enantiospecifically with chiral adsorbates. Enantioselective desorption of small chiral molecules from such surfaces has been demonstrated and studied, but enantioselective reactivity on naturally chiral metal surfaces has not been explored. Temperature Programmed Reaction Spectroscopy (TPRS) has been used to study the decomposition of R-2-bromobutane on the chiral Cu(531)@super R@ and Cu(531)@super S@ surfaces. R-2-bromobutane debrominates to produce a chiral R-2-butyl intermediate. The R-2-butyl group decomposes by @beta@-hydride elimination to form cis- and trans-2-butene and 1-butene. The hydrogen released by @beta@-hydride elimination can also hydrogenate the R-2-butyl intermediate to form butane. In addition to reaction temperatures that are indicative of enantioselective kinetics, the reaction yield is influenced by the chirality of the Cu(531) surfaces.