Alignment and Dynamic Inversion of Planar Chirality in Pillar[n]arenes

Abstract

Pillar[n]arenes are symmetrical macrocyclic compounds composed of benzene panels with para‐methylene linkages. Each panel usually exhibits planar chirality and prefers chirality‐aligned states. Because of this feature, pillar[n]arenes are attractive scaffolds for chiroptical materials that are easy to prepare and optically resolve and show intense circular dichroism (CD) signals. In addition, rotation of the panels endows the chirality of pillar[n]arenes with a dynamic nature. The chirality in tubular oligomers and supramolecular assemblies sometimes show time‐ and procedure‐dependent alignment phenomena. Furthermore, the CD signals of some pillar[n]arenes respond to the addition of chiral guests when their dynamic chirality is coupled with host–guest properties. By using diastereomeric pillar[n]arenes with additional chiral structures, the response can also be caused by achiral guests and changes of the environment, providing molecular sensors.

Functionalization of pillar[n]arenes towards optically responsive systems via host–guest interactions

“…Interconversion between pS and pR forms occurs by unit rotations. 67,68 Experimental and calculated results show that negative and positive CD signals at 310 nm in the range of π–π* transitions are observed from the pS and pR forms, respectively. 107–109 Therefore, CD signals can be induced by creating an unequal population of the pS / pR isomers.…”

“…1f). [67][68][69][70] Chiroptical properties, such as circular dichroism (CD) and circularly polarized luminescence (CPL), that arise because of this planar chirality have been studied. Furthermore, interconversion between pS and pR forms occurs because of rotation of benzene units.…”

有机硼氮（b/N）圆偏振发光手性分子的研究进展：合成、结构及其性能表征

“…结构， 从而对其前线轨道分布和能带结构产生显著影 响 [36][37][38][39][40][41][42][43] 。近年来，主族元素掺杂的化合物在 CPL 发 光中也体现出了一定优势 [44][45][46][47][48] [49][50][51][52][53][54] 。 例如 2020 年，我们课题组首次报道了一种新型手性 有机硼(氮)化合物(P5NN 和 P5BN)的合成与性…”

Linking Nitrogen-Rich Pillar[5]arene to Hyper-Cross-Linked Polymers for Efficient and Simultaneous Capture of Iodine and Methyl Iodide

“…Among them, pillar­[ n ]­arenes (P­[ n ]­A) are a macrocyclic host with rigid pillars and π-electron-rich external walls/cavities. They are often functionalized on the rims or incorporated into materials to impart physicochemical properties − or significant functions, such as environmental remediation, − disease diagnosis, and luminescence detection. − …”