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

Elementary steps in enantioselective heterogeneous catalysis take place on the catalyst surface and the targeted synthesis of a desired enantiomer requires the implantation of chiral information at the surface, which can be achieved-for example-by adsorbing chiral molecules. Studies of the structures of complexes formed between adsorbed prochiral reagents and chiral molecules yield information on the forces exerting stereocontrol, but further insight could be gained by studying the dynamics of their interactions. Here, using time-lapsed scanning tunnelling microscopy and density functional theory, we observe coupling between multiple stereochemical states within individual non-covalently bonded chirality-transfer complexes 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 states of opposing prochirality in the process. These results provide insight on the contribution of individual stereochemical states to the overall enantioselectivity of reactions occurring on catalyst surfaces.