The NanoSciences Group, Centre d'élaboration de matériaux et d'études structurales (CEMES) CNRS and University of Toulouse III Paul Sabatier, 29 rue Jeanne-Marvig, BP 94347, F-31005 Toulouse Cedex 4, France.
J Chem Phys. 2010 Feb 21;132(7):074705. doi: 10.1063/1.3314725.
The adsorption of indigo molecules on Cu(111) was investigated by low temperature (5 K) scanning tunneling microscopy from the isolated single molecule regime to one monolayer. Structural optimization and image calculations demonstrate that the molecules are in a physisorbed state. Because of the reduced symmetry at the surface, single molecules acquire a chiral character upon adsorption leading to a two-dimensional (2D) chirality. They adopt two adsorption configurations, related by a mirror symmetry of the substrate, each with a distinct molecular orientation. Consequently, the 2D chirality is expressed by the orientation of the molecule. For higher coverage, molecules self-assemble by hydrogen bonding in nearly homochiral molecular chains, whose orientation is determined by the orientation taken by the isolated molecules. When the coverage approaches one monolayer, these chains pack into domains. Finally, the completion of the monolayer induces the expulsion of the molecules of the wrong chirality that are still in these domains, leading to perfect resolution in enantiopure domains.
通过从孤立的单分子状态到单层的低温（5 K）扫描隧道显微镜，研究了靛蓝分子在 Cu(111)上的吸附。结构优化和图像计算表明，分子处于物理吸附状态。由于表面的对称性降低，单个分子在吸附后获得手性特征，导致二维（2D）手性。它们采用两种吸附配置，通过基底的镜像对称相关，每种配置都具有独特的分子取向。因此，2D 手性由分子的取向表达。对于更高的覆盖率，分子通过氢键自组装成几乎同手性的分子链，其取向由孤立分子的取向决定。当覆盖率接近单层时，这些链组装成域。最后，单层的完成会排斥仍在这些域中的错误手性的分子，导致在纯对映体域中具有完美的分辨率。
