Enantioselective Reactions on Model Chirally Modified Surfaces



Imparting chirality to non-chiral metal surfaces by adsorption of chiral modifiers is a highly promising route to create effective heterogeneously catalyzed processes for production of enantiopure pharmaceuticals. A molecular-level understanding of enantioselective processes on chiral surfaces is an importance prerequisite for the rational design of new enantiospecific catalysts. In our studies, we are aiming at a fundamental level understanding of the structure of chirally modified surfaces, the bonding of the prochiral substrate on the chiral media and the details of the kinetics and dynamics of enantioselective surface reactions. A full mechanistic picture can be obtained if these aspects will be understood both on the extended single crystal surfaces, mimicking a local interaction of the modifier-substrate complexes with a metal, as well as on the small chirally modified nanoparticles that more accurately resemble the structural properties and high catalytic activity of practically relevant powdered supported catalyst. To achieve these atomistic insights, we apply a combination of ultrahigh vacuum (UHV) based methods for studying reaction kinetics and dynamics (multi-molecular beam techniques) and in-situ surface spectroscopic and microscopic tools on well-defined model surfaces consisting of metal nanoparticles supported on thin single crystalline oxide films. Complementary, the catalytic behaviour of these chirally modified model surfaces is investigated under ambient pressure conditions with enantiospecific detection of the reaction products that enables detailed atomistic insights into structure-reactivity relationships.