Bera Abhijit, Henkel Stefan, Mieres-Perez Joel, Andargie Tsegaw Yetsedaw, Sanchez-Garcia Elsa, Sander Wolfram, Morgenstern Karina
Physikalische Chemie I, Ruhr-Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
Organic Chemistry II, Ruhr-Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
Angew Chem Int Ed Engl. 2022 Oct 24;61(43):e202212245. doi: 10.1002/anie.202212245. Epub 2022 Sep 29.
Chirality switching of self-assembled molecular structures is of potential interest for designing functional materials but is restricted by the strong interaction between the embedded molecules. Here, we report on an unusual approach based on reversible chirality changes of self-assembled oligomers using variable-temperature scanning tunneling microscopy supported by quantum mechanical calculations. Six functionalized diazomethanes each self-assemble into chiral wheel-shaped oligomers on Ag(111). At 130 K, a temperature far lower than expected, the oligomers change their chirality even though the molecules reside in an embedded self-assembled structure. Each chirality change is accompanied by a slight center-of-mass shift. We show how the identical activation energies of the two processes result from the interplay of the chirality change with surface diffusion, findings that open the possibility of implementing various functional materials from self-assembled supramolecular structures.
自组装分子结构的手性转换对于设计功能材料具有潜在的意义，但受到嵌入分子间强相互作用的限制。在此，我们报道了一种基于自组装低聚物可逆手性变化的不同寻常的方法，该方法利用了可变温度扫描隧道显微镜，并辅以量子力学计算。六种功能化重氮甲烷各自在Ag(111)上自组装成手性轮状低聚物。在130 K（一个远低于预期的温度）时，尽管分子处于嵌入的自组装结构中，低聚物仍会改变其手性。每次手性变化都伴随着质心的轻微移动。我们展示了这两个过程相同的活化能是如何由手性变化与表面扩散的相互作用产生的，这些发现为从自组装超分子结构实现各种功能材料开辟了可能性。
