Self‐Assembly of Helical Nanofibrous Chiral Covalent Organic Frameworks. Issue 4 (14th December 2022)

• Record Type: Journal Article
• Authors: Tang, Xihao; Liao, Xiangji; Cai, Xinting; Wu, Jialin; Wu, Xueying; Zhang, Qianni; Yan, Yilun; Zheng, Shengrun; Jiang, Huawei; Fan, Jun; Cai, Songliang; Zhang, Weiguang; Liu, Yi
• Is Part Of: Angewandte Chemie international edition. Volume 62:Issue 4(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-14
• Subjects: Chiral Covalent Organic Frameworks -- Chiral Inversion -- Circularly Polarized Luminescence -- Helical Nanofibrous Morphology; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202216310
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Despite significant progress on the design and synthesis of covalent organic frameworks (COFs), precise control over microstructures of such materials remains challenging. Herein, two chiral COFs with well‐defined one‐handed double‐helical nanofibrous morphologies were constructed via an unprecedented template‐free method, capitalizing on the diastereoselective formation of aminal linkages. Detailed time‐dependent experiments reveal the spontaneous transformation of initial rod‐like aggregates into the double‐helical microstructures. We have further demonstrated that the helical chirality and circular dichroism signal can be facilely inversed by simply adjusting the amount of acetic acid during synthesis. Moreover, by transferring chirality to achiral fluorescent molecular adsorbents, the helical COF nanostructures can effectively induce circularly polarized luminescence with the highest luminescent asymmetric factor ( g lum ) up to ≈0.01. Abstract : Two chiral COFs with well‐defined, one‐handed double‐helical nanofibrous morphologies are constructed for the first time involving a chiral aminal linkage. By adjusting the amount of acetic acid during synthesis, the helicity of the resulting COF double helices can be readily inversed. Circularly polarized luminescence of the COF double helices is achieved via transferring chirality to achiral fluorophores.