April 2017   (Technical report   )

Monitoring interconversion between stereochemical states in single chirality-transfer complexes on a platinum surface

Guillaume Goubert, Yi Dong, Michael N. Groves, Jean-Christian Lemay, Bjørk Hammer, Peter McBreen

Elementary steps in enantioselective heterogeneous catalysis take place on the catalyst surface and the targeted synthesisof a desired enantiomer requir es the implantation of chiral informa tion at the surface, which can be achieve d—for example—by adsorbing chiral molecules. Studies of the structures of complexes formed between adsorbed prochiral reagents andchiral molecules yield information on the forces exerting stereocontrol, but further insight could be gained by studying thedynamics of their interactions. Here, using time-lapsed scanning tunnelling microscopy and density functional theory, weobserve coupling between multiple stereochemical states within individual non-covalently bonded chirality-transfercomplexes on a metal surface. We identify two modes of transformation between stereochemical states and find that the prochiral reagent can sample several complexation geometries during the lifetime of a complex, switching between statesof opposing prochirality in the process. These results provide insight on the contribution of individual stereochemicalstates to the overall enantioselectivity of reactions occurring on catalyst surfaces.

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