Morimoto Kohei, Tsujioka Hajime, Kitagawa Daichi, Kobatake Seiya
Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
J Phys Chem A. 2020 Jun 11;124(23):4732-4741. doi: 10.1021/acs.jpca.0c02774. Epub 2020 Jun 1.
Stimuli-responsive organic crystals represent a new frontier of material chemistry. Recently, we have reported photoreversible interference color change to multicolor in single crystals composed of a photochromic diarylethene derivative, 1,2-bis(2-ethyl-5-phenyl-3-thienyl)perfluorocyclopentene (), accompanied by the photochromic reaction. The origin of the interference color change is due to the photoinduced birefringence change in the photoisomerization of diarylethenes. In this study, we newly found that single crystals composed of 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene () also exhibit a photoreversible interference color change. The birefringence value for crystal increased with the photocyclization conversion, while that for crystal decreased. The relationship between the photoinduced birefringence changes for crystals and and their molecular structures was discussed based on the change in the molecular polarizability anisotropy accompanied by the photochromic reaction. These results would provide not only new opportunities for the application of photochromic crystals but also useful strategies for the design of crystalline materials that exhibit the desired birefringence change.
刺激响应性有机晶体代表了材料化学的一个新前沿。最近，我们报道了由光致变色二芳基乙烯衍生物1,2-双(2-乙基-5-苯基-3-噻吩基)全氟环戊烯（）组成的单晶中光致变色反应伴随的光可逆干涉颜色向多色的变化。干涉颜色变化的起源是由于二芳基乙烯光异构化过程中的光致双折射变化。在本研究中，我们新发现由1,2-双(2,5-二甲基-3-噻吩基)全氟环戊烯（）组成的单晶也表现出光可逆干涉颜色变化。晶体的双折射值随着光环化转化率的增加而增加，而晶体的双折射值则降低。基于光致变色反应伴随的分子极化率各向异性的变化，讨论了晶体和晶体的光致双折射变化与其分子结构之间的关系。这些结果不仅将为光致变色晶体的应用提供新的机会，也为设计具有所需双折射变化的晶体材料提供有用的策略。
