Fukunaga Toshiya M, Sawabe Chizuru, Matsuno Taisuke, Takeya Jun, Okamoto Toshihiro, Isobe Hiroyuki
Department of Chemistry, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan.
Material Innovation Research Center (MIRC) and Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba, 277-8561, Japan.
Angew Chem Int Ed Engl. 2021 Aug 23;60(35):19097-19101. doi: 10.1002/anie.202106992. Epub 2021 Jul 19.
A desymmetrization strategy has been devised in the design of molecular cylinders to maximize the dissymmetry factor relevant to circularly polarized light. Although the highest dissymmetry factor of organic molecules was previously achieved with a chiral belt-persistent cycloarylene having magnetic and electric transition dipole moments in parallel, we noticed that an unbalanced magnitude of two moments was detrimental for higher dissymmetry factors. In this study, a molecular cylinder was desymmetrized by arraying doped and undoped panels via stereoselective cross-coupling macrocyclization. The desymmetrization succeeded in balancing two moments by reducing the electric transition moment at the global minimum but failed to maximize the dissymmetry factor. Structural studies revealed that the dissymmetry factor is sensitive to subtle structural fluctuations, while the rotatory strength is not affected. This study is important for the development of chiroptical materials.
在分子圆柱体的设计中，已经设计出一种去对称化策略，以最大化与圆偏振光相关的不对称因子。尽管有机分子的最高不对称因子先前是通过具有平行磁和电跃迁偶极矩的手性带状持久环芳烯实现的，但我们注意到，两个矩的大小不平衡不利于获得更高的不对称因子。在本研究中，通过立体选择性交叉偶联大环化排列掺杂和未掺杂面板，使分子圆柱体去对称化。这种去对称化成功地通过在全局最小值处降低电跃迁矩来平衡两个矩，但未能使不对称因子最大化。结构研究表明，不对称因子对细微的结构波动敏感，而旋光强度不受影响。这项研究对于手性光学材料的开发很重要。
