Kato Kenichi, Kurakake Yuta, Ohtani Shunsuke, Fa Shixin, Gon Masayuki, Tanaka Kazuo, Ogoshi Tomoki
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
Angew Chem Int Ed Engl. 2022 Sep 12;61(37):e202209222. doi: 10.1002/anie.202209222. Epub 2022 Aug 3.
Control of symmetry is fundamental in molecular design with aimed properties. Herein we report a set of chiroptical C -symmetric molecules with variable dipolar structures based on a rim-differentiated cylindrical macrocycle, pillar[5]arene. Incorporation of electron-withdrawing ester groups formed an explicit two-sided structure, leading to increase in response wavelength and luminescence efficiency. On the other hand, chiroptical measurement of separated enantiomers revealed that such a dipolar character diminished dissymmetry of the electronic transitions. By suppressing the dipole, the dissymmetry factor for luminescence was enhanced from 0.4×10 to 5.1×10 in a less dipolar methoxy-substituted molecule, which was larger than reported pillar[5]arene derivatives without C -symmetry around one order of magnitude.
对称性控制是具有目标性质的分子设计的基础。在此，我们报道了一组基于边缘差异化的柱状大环分子柱[5]芳烃的具有可变偶极结构的手性光活性C对称分子。引入吸电子酯基形成了明确的双侧结构，导致响应波长和发光效率增加。另一方面，对分离的对映体进行的手性光活性测量表明，这种偶极特性降低了电子跃迁的不对称性。通过抑制偶极，在偶极较小的甲氧基取代分子中，发光的不对称因子从0.4×10提高到5.1×10，这比报道的没有C对称性的柱[5]芳烃衍生物大约一个数量级。
