Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
J Am Chem Soc. 2023 Mar 29;145(12):6905-6913. doi: 10.1021/jacs.3c00397. Epub 2023 Mar 17.
Installation of various substituents is a reliable and versatile way to alter the properties of macrocyclic molecules, but high-yield and controlled methods are not always available especially for multifold reactions. Herein, we report 10- and 12-fold introduction of aryl substituents onto both rims of cylinder-shaped pillar[]arenes, which usually have alkoxy substituents slanting to the cylinder axes. Although alkoxy pillar[5]arenes exist as -symmetric enantiomeric pairs, arylated pillar[5]arenes provide crushed single-crystal structures and stereoisomerism including -symmetric conformations depending on the aryl groups. Pillar[]arenes with 2-benzofuranyl groups display bright fluorescence with quantum yields of 88-90% and no host-guest complexation with electron-deficient molecules in solution due to large deviation from alkoxy compounds. A benzofuran-appended pillar[6]arene instead captures small gaseous molecules in the solid state, probably owing to outside spaces surrounded by aromatic rings.
安装各种取代基是改变大环分子性质的一种可靠且通用的方法，但高产率和可控的方法并不总是可用的，特别是对于多步反应。在此，我们报告了将芳基取代基以 10 倍和 12 倍的比例引入到柱[]芳烃的两个边缘，这些柱[]芳烃通常具有倾斜于柱轴的烷氧基取代基。尽管烷氧基柱[5]芳烃以 -对称对映体的形式存在，但芳基化的柱[5]芳烃提供了粉碎的单晶结构和立体异构性，包括 -对称构象，具体取决于芳基。带有 2-苯并呋喃基的柱[]芳烃具有 88-90%的量子产率的明亮荧光，并且由于与烷氧基化合物的大偏差，在溶液中不与缺电子分子形成主客体配合物。而苯并呋喃取代的柱[6]芳烃则在固态中捕获小分子气体，这可能是由于被芳香环包围的外部空间所致。
