Freund Sara, Pawlak Rémy, Moser Lucas, Hinaut Antoine, Steiner Roland, Marinakis Nathalie, Constable Edwin C, Meyer Ernst, Housecroft Catherine E, Glatzel Thilo
Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, CH-4058 Basel, Switzerland.
ACS Omega. 2018 Oct 9;3(10):12851-12856. doi: 10.1021/acsomega.8b01792. eCollection 2018 Oct 31.
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.
构象异构体是立体异构体，可通过围绕单键旋转越过低势能垒进行相互转化。然而，当分子吸附在表面时，这种键的旋转会受到几何限制的阻碍。在这里，我们表明，4,4'-双(4-羧基苯基)-6,6'-二甲基-2,2'-联吡啶分子在表面的吸附导致在NiO(001)上出现前手性单分子，并在含有反式分子构象的Au(111)表面上形成对映体纯的超分子域。在额外沉积铁吸附原子后，由于铁原子与2,2'-联吡啶部分的配位作用，分子经历了从反式到顺式构象的可控相互转化。如原子力显微镜图像和X射线光电子能谱测量所证实的，所得分子结构不可逆地变为非手性。
