AVS 60th International Symposium and Exhibition
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS+AS+EN+SS-TuA

Paper NS+AS+EN+SS-TuA4
Trends in Reactivity of Organic Compounds on a Model Gold Catalyst

Tuesday, October 29, 2013, 3:00 pm, Room 203 B

Session: Nanoscale Catalysis and Surface Chemistry
Presenter: J.C. Rodriguez-Reyes, Universidad de Ingeniería y Tecnología, UTEC, Peru
Authors: J.C. Rodriguez-Reyes, Universidad de Ingeniería y Tecnología, UTEC, Peru
C.M. Friend, Harvard University
R.J. Madix, Harvard University
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The perception that gold is chemically inert has faded in the light of the unique properties of this metal as an environmentally friendly catalyst. To date, the contrast between the large number of gold-based catalysts reported and the very limited number of probe molecules employed to test their efficiency has hindered the possibility of using gold beyond the laboratory scale and into an industrial scale as a practical catalyst. In this presentation, our efforts towards the elucidation of a reactivity scale for various organic molecules (including alcohols, amines, hydrocarbons, carboxylic acids and thiols) are discussed. The use of controlled (ultra-high vacuum) conditions allows for an assessment of the intrinsic behavior of gold as catalyst, with the mass spectrometric detection of desorbing products allowing both the identification of reactive species and the extraction of thermodynamics and kinetics parameters of importance for future studies. The results confirm that the first steps in gold-mediated reactions involve the dehydrogenation of a probe molecule and, therefore, there is a relationship between the gas-phase acidity of a molecule and its reactivity on gold. However, this relationship is modified by several factors including 1) the strength of the interaction of a functional group with the gold surface, 2) the presence of aromatic groups and long alkyl chains within a molecule, and 3) the presence of substituents able to modify the first two factors. The elucidation of a reactivity scale is anticipated to expand and direct the range of gold-mediated catalytic conversions.