Transoid-to-Cisoid Conformation Changes of Single Molecules on Surfaces Triggered by Metal Coordination

• Published in: ACS omega 2018-10, Vol.3 (10), p.12851-12856
• Main Authors: Freund, Sara, Pawlak, Rémy, Moser, Lucas, Hinaut, Antoine, Steiner, Roland, Marinakis, Nathalie, Constable, Edwin C, Meyer, Ernst, Housecroft, Catherine E, Glatzel, Thilo
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.8b01792

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 prochiral 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.