Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 74: Organic Molecules at Surfaces 5: Molecular Switches

O 74.8: Vortrag

Donnerstag, 8. September 2022, 16:45–17:00, S054

Tuning the chirality change of a single molecule by van der Waals interactions — •Yunjun Cao and Karina Morgenstern — Physical Chemistry I, Ruhr-Universität Bochum, Bochum, Germany

The chiral induction and control of molecules by non-covalent intermolecular interactions, like hydrogen bonding and van der Waals interactions, is crucial to understand the origin of homochirality in nature. However, it remains challenging to address these subtle intermolecular interactions at a single-molecular level, especially the weakest of them, the van der Waals interactions. Here, by adsorbing a specifically designed carbene molecule on a copper surface, we examine the influence of the van der Waals interactions on the chirality induction by scanning tunneling microscopy. While the strongly binding carbene center of this molecule suppresses any side-reactions upon excitation, its two low-interacting phenyl rings facilitate a chirality change induced by inelastically tunneling electrons. The potential energy of the chirality change is modified by the van der Waals interactions in the presence of a tip. A marginal change induces an asymmetric distribution of the carbene molecule between its two enantiomers during this chirality change. Our study shows how the weak van der Waals interactions alter the dynamics of chirality changes at the molecular level, enabling an in-depth understanding of the origin of homochirality in nature and providing new insights into the construction of homochiral supramolecular assemblies in solutions and on solid surfaces.