| Institution: | 1. GDMPA Key Laboratory for Process Control and Quality Evaluation of Chiral Pharmaceuticals, and Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou, 510006 China;2. State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 China;3. GDMPA Key Laboratory for Process Control and Quality Evaluation of Chiral Pharmaceuticals, and Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou, 510006 China
SCNU Qingyuan Institute of Science and Technology Innovation Co., Ltd., Qingyuan, 511517 China;4. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA-94720 USA |
| 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 (glum) up to ≈0.01. |
