Moriya Miyu, Kohri Michinari, Kishikawa Keiki
Department of Applied Chemistry and Biotechnology, Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Department of Applied Chemistry and Biotechnology, Graduate School of Engineering and Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
ACS Omega. 2021 Jul 10;6(28):18451-18457. doi: 10.1021/acsomega.1c02534. eCollection 2021 Jul 20.
An axially polar-ferroelectric columnar liquid crystal (AP-FCLC) phase that exhibits both switching and maintenance of the macro-polarity in the column axis direction has been achieved in an ,'-bis(3,4,5-trialkoxyphenyl)urea compound (-) prepared from (±)-citronellyl bromide. Although it had been thought that chirality is necessary to achieve the AP-FCLC phase from our previous study, the optically inactive compound which is a mixture of 21 stereoisomers, generated an AP-FCLC phase. We confirmed its ferroelectricity and investigated the mechanism for realizing the AP-FCLC phase using optoelectronic experiments, X-ray diffraction, and circular dichroism spectroscopy. As a result, it was suggested that chiral self-sorting occurs in the columnar liquid crystal phase, in which molecules with a similar stereochemistry form a one-handed helical column, and columns with the same helicity gather together to form a chiral domain. Accordingly, we conclude that the optically inactive compound - also indicates ferroelectricity similar to that of an optically pure urea compound because of chiral self-sorting.
在由（±）-香茅基溴制备的α，ω-双（3,4,5-三烷氧基苯基）脲化合物（-）中，已实现了一种轴向极化铁电柱状液晶（AP-FCLC）相，该相在柱轴方向上兼具宏观极性的切换和维持特性。尽管根据我们之前的研究认为手性对于实现AP-FCLC相是必要的，但这种由21种立体异构体组成的非光学活性化合物却产生了AP-FCLC相。我们证实了其铁电性，并通过光电实验、X射线衍射和圆二色光谱研究了实现AP-FCLC相的机制。结果表明，在柱状液晶相中发生了手性自分类，其中具有相似立体化学结构的分子形成单手螺旋柱，并且具有相同螺旋度的柱聚集在一起形成手性畴。因此，我们得出结论，由于手性自分类，这种非光学活性化合物-α也表现出与光学纯脲化合物相似的铁电性。
