Circularly Polarized Luminescence from Chiral p ‐Terphenylene‐Based Supramolecular Aggregates

Herein, a pair of chiral macrocyclic luminogens derived from chiral 1,1-bi(2-naphthol) (BINOL) and tetraphenylethenes (TPEs) have been prepared with high yield via intramolecular McMurry coupling, in which the preferential helicity of propeller-shaped TPE units can be tuned via choosing proper chiral BINOL tethers. The preferential chiral geometry of the macrocyclic luminogen was unambiguously confirmed by X-ray crystal crystallography and theoretical calculation, whereas the variable-temperature NMR spectra and chiral HPLC analysis further verified the intramolecular motions. These two chiral macrocyclic luminogens both exhibit obvious aggregation-induced emission behavior and mechanochromic luminescence properties. Furthermore, aggregation attenuated CD signals and circularly polarized luminescence were observed for these two chiral macrocylic luminogens in THF-water mixture and PMMA matrix. These results had paved a new approach toward constructing chiral aggregation-induced emission luminogens (AIEgens) and their structural engineering.

Chiral Macrocyclic AIEgens from BINOL and Tetraphenylethene via Tailoring Chirality of Luminescent Molecular Propellers

Wang

Liu

et al. 2022

Enhancing the Circularly Polarized Luminescence of Self‐assembled Cyanostilbenes through Extended π‐Conjugation

Lv,

Wu,

Jin

et al. 2023

Main observation and conclusionChiral supramolecular assembly of π‐conjugated luminophores provides a promising avenue for enhancing circularly polarized luminescence. In this study, we shed light on the impact of π‐conjugation length on circularly polarized luminescent performance of the resulting supramolecular assemblies, by designing a tetra‐cyanostilbene monomeric compound alongside two dicyanostilbene control compounds. These cyanostilbene‐based compounds possess the ability to form chiral supramolecular polymers in toluene, driven by a synergistic combination of intermolecular hydrogen bonding and π–π stacking interactions. The extended π‐aromatic skeleton brings bathochromic‐shifted fluorescence and enhanced intermolecular stacking capability for the tetra‐cyanostilbene compound. Consequently, chiral supramolecular assemblies formed by the tetra‐cyanostilbene compound demonstrate a remarkable two‐fold increase in glum values relative to the assemblies formed by the dicyanostilbene compounds. Overall, this study provides valuable insights into the relationship between π‐conjugation length and the circularly polarized luminescent performance of π‐conjugated supramolecular assemblies.This article is protected by copyright. All rights reserved.

Cholesterol Decorated Diazocine Gelator with Photo‐ and Thermo‐Responsive Properties for Smart Window

Wang,

Yuan,

Zhang

et al. 2024

Comprehensive SummaryA new gelator (BAzo‐Chol) comprising a diazocine core and two cholesterol units linked via carbamate groups has been designed and synthesized. Its gelation ability in several kinds of organic solvents is identified. Investigations with scanning electron microscopy (SEM), transmission electron microscopy (TEM), rheological measurements, and UV‐vis absorption and 1H NMR spectroscopy reveal that BAzo‐Chol can self‐assemble into elastically interpenetrating one‐dimensional nanostructures in organogels through a cooperative effect of the π‐π interactions, hydrogen‐bonding, and van der Waals forces. Moreover, the unconventional Z/E conformational transitions of these organogels, due to the inclusion of diazocine, endow the BAzo‐Chol gels with excellent photo‐responsive gel‐sol transition and remarkable visible light‐induced chromic properties. Lastly, due to its sensitive response to visible light accompanied by distinct changes in both colour and transparency of the gel‐sol transitions, the potential application of the current gelator in smart windows is signified.