Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan.
Chemistry. 2019 Feb 6;25(8):2011-2018. doi: 10.1002/chem.201804688. Epub 2019 Jan 9.
A unique and effective interaction between the peripheral aromatic blades makes hexaarylbenzenes (HABs) attractive in fundamental research as well as for various applications such as molecular wires, sensors, and supramolecular assemblies. The chiroptical responses of HABs are susceptible to environmental factors such as solvent and temperature owing to the dynamic conformational transitions between the conformers. In this study, pressure dependence on the propeller chiral HABs in two different solvents was studied in detail. The effective differential volumes for two different equilibria were determined by quantitative analyses of CD spectra, affording very large differential volumes from the propeller to toroidal conformer (ΔV ) of +43 and +42 cm mol , for H2 and H6, respectively, in methylcyclohexane. The value of H6 was further enhanced to +72 cm mol in hexane, the largest value for the typical unimolecular conformational change. Such a response of propeller chirality in HABs is expedient in designing more advanced piezo-sensitive materials.
外围芳香刀片之间的独特而有效的相互作用使六芳基苯（HABs）在基础研究以及各种应用中都很有吸引力，例如分子导线、传感器和超分子组装。由于构象体之间的动态构象转变，HABs 的手性光学响应容易受到溶剂和温度等环境因素的影响。在这项研究中，详细研究了两种不同溶剂中螺旋桨手性 HABs 的压力依赖性。通过对 CD 光谱的定量分析确定了两种不同平衡的有效差体积，从而为螺旋桨到手性（ΔV）的转变提供了非常大的差体积，对于甲基环己烷中的 H2 和 H6，分别为+43 和+42cm 3mol -1。在己烷中，H6 的值进一步增加到+72cm 3mol -1，这是典型的单分子构象变化的最大值。HABs 中螺旋桨手性的这种响应有利于设计更先进的压敏材料。
