Conformational isomers are stereoisomers that can interconvert over low potential barriers by rotation around a single bond. However, such bond rotation is hampered by geometrical constraints when molecules are adsorbed on surfaces. Here we show that the adsorption of 4,4'-bis(4-carboxyphenyl)-6,6'-dimethyl-2,2'-bipyridine molecules on surfaces leads to the appearance of pro-chiral single-molecules on NiO(001) and to enantiopure supramolecular domains on Au(111) surfaces containing the transoid molecule conformation. Upon additional Fe adatom deposition, molecules undergo a controlled interconversion from a transoid to cisoid conformation as a result of coordination of the Fe atoms to the 2,2'-bipyridine moieties. As confirmed by atomic force microscopy images and X-ray photoelectron spectroscopy measurements, the resulting molecular structures become irreversibly achiral.
@article{arxiv.1807.04011,
title = {Transoid-to-Cisoid Conformation Changes of Single Molecules on Surfaces Triggered by Metal Coordination},
author = {Sara Freund and Rémy Pawlak and Lucas Moser and Antoine Hinaut and Roland Steiner and Nathalie Marinakis and Edwin C. Constable and Ernst Meyer and Catherine E. Housecroft and Thilo Glatzel},
journal= {arXiv preprint arXiv:1807.04011},
year = {2018}
}