Ikai Tomoyuki, Wada Yuya, Awata Seiya, Yun Changsik, Maeda Katsuhiro, Mizuno Motohiro, Swager Timothy M
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Org Biomol Chem. 2017 Oct 11;15(39):8440-8447. doi: 10.1039/c7ob02046e.
A pair of optically pure triptycene derivatives ((R,R)- and (S,S)-3) containing fluorescent pyrene-based π-conjugated pendant groups attached through amide spacers were prepared via a resolution step using chiral high-performance liquid chromatography. Their absorption, circular dichroism, photoluminescence and circularly polarized luminescence (CPL) properties were investigated under various solution conditions. (R,R)- and (S,S)-3 exhibited clear solvent- and concentration-dependences of the optical and chiroptical properties as a result of the interconversion between molecularly dispersed and aggregate states. We also observed that (R,R)- and (S,S)-3 emitted left- and right-handed circularly polarized light, respectively, upon UV irradiation under aggregation conditions, and their dissymmetry factors were found to be greater than 1.0 × 10. Based on the contrasting result that almost no CPL signal appeared in the monomeric solution state, the resulting CPL was considered to arise from the supramolecular chirality induced in the hydrogen-bonded aggregate, wherein the pyrenyl pendants of 3 were most likely arranged in a preferred-handed twisting structure.
通过手性高效液相色谱的拆分步骤，制备了一对光学纯的三联苯衍生物（(R,R)-3和(S,S)-3），其含有通过酰胺间隔基连接的基于芘的荧光π共轭侧基。在各种溶液条件下研究了它们的吸收、圆二色性、光致发光和圆偏振发光（CPL）性质。由于分子分散态和聚集态之间的相互转化，(R,R)-3和(S,S)-3表现出明显的光学和手性光学性质的溶剂和浓度依赖性。我们还观察到，在聚集条件下进行紫外线照射时，(R,R)-3和(S,S)-3分别发射左旋和右旋圆偏振光，并且发现它们的不对称因子大于1.0×10。基于在单体溶液状态下几乎没有CPL信号出现的对比结果，认为所得的CPL源于氢键聚集体中诱导的超分子手性，其中3的芘基侧链最有可能排列成优选手性的扭曲结构。
