A Dynamic Hydrogen‐Bonded Azo‐Macrocycle for Precisely Photo‐Controlled Molecular Encapsulation and Release

• Published in: Angewandte Chemie Vol. 131; no. 36; pp. 12649 - 12653
• Main Authors: Ye, Zecong, Yang, Zhiyao, Wang, Lei, Chen, Lixi, Cai, Yimin, Deng, Pengchi, Feng, Wen, Li, Xiaopeng, Yuan, Lihua
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 02.09.2019
• Subjects: Cage molecules; Cations; Chemistry; Encapsulation; Exchanging; Ionic mobility; Irradiation; Light irradiation; Mass spectrometry; Mass spectroscopy; Molecular machines; NMR; Nuclear magnetic resonance; Photochemie; Präzise Freisetzung; Radiation; Stoichiometry; Supramolekulare Chemie; Switches; Traveling waves; Wasserstoffverbrückter Makrocyclus; Wirt-Gast-Systeme
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201906912

A light‐responsive system constructed from hydrogen‐bonded azo‐macrocycles demonstrates precisely controlled propensity in molecular encapsulation and release process. A significant decrease in the size of the cavity is observed in the course of the E→Z photoisomerization based on the results from DFT calculations and traveling wave ion mobility mass spectrometry. These macrocyclic hosts exhibit a rare 2:1 host–guest stoichiometry and guest‐dependent slow or fast exchange on the NMR timescale. With the slow host–guest exchange and switchable shape change of the cavity, quantitative release and capture of bipyridinium guests is achieved with the maximum release of 68 %. This work underscores the importance of slow host–guest exchange on realizing accurate release of organic cations in a stepwise manner under light irradiation. The light‐responsive system established here could advance further design of novel photoresponsive molecular switches and mechanically interlocked molecules. Ein photoresponsives Wirt‐Gast‐System auf der Basis von wasserstoffverbrückten Azomakrocyclen und Viologen im langsamen Austausch zeigt eine präzise kontrollierte molekulare Verkapselung und schrittweise Freisetzung. Die Ergebnisse zeigen Anwendungspotenzial für photogesteuerte molekulare Maschinen auf.