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

Sara Freund; Rémy Pawlak; Lucas Moser; Antoine Hinaut; Roland Steiner; Nathalie Marinakis; Edwin C Constable; Ernst Meyer; Catherine E Housecroft; Thilo Glatzel

doi:10.1021/acsomega.8b01792

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

ACS Omega. 2018 Oct 9;3(10):12851-12856. doi: 10.1021/acsomega.8b01792. eCollection 2018 Oct 31.

Affiliations

¹ Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
² Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, CH-4058 Basel, Switzerland.

Abstract

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.