华中农业大学项勇刚团队报道了通过铑催化脱氢环化构建超稳定非取代喹啉桥联共价有机框架。相关研究成果发表在2022年8月23日出版的《德国应用化学》。

探索锁定亚胺连接的共价有机框架（COFs）中动态C=N键的新途径来对于增强其稳定性和功能性非常重要。

该文提出了一种通过铑催化[4+2]环化的新型C=N桥锁定策略，以构建非取代喹啉连接的COFs（NQ-COFs）。该策略的显著特征包括高C=N转化效率、无氧化剂以及合成具有高化学稳定性的各种NQ-COFs的通用性。特别是，在合成后改性，原始亚胺连接的COFs的结晶度、拓扑结构和孔隙率得到很好的保留。当用作光催化剂时，NQ-COFs由于增强的面内π共轭能力以及比其对应物更容易产生超氧阴离子自由基，而显示出更好的可见光吸收和载体分离效率，从而高效合成2,4,6-三（芳基）吡啶、苯并咪唑和亚砜衍生物。

附：英文原文

Title: Construction of Ultrastable Nonsubstituted Quinoline-Bridged Covalent Organic Frameworks via Rhodium-Catalyzed Dehydrogenative Annulation

Author: Xiaodong Zhao, Huaji Pang, Dekang Huang, Gang Liu, Jianxiang Hu, Yonggang Xiang

Issue&Volume: 2022-08-23

Abstract: Exploring new routes to lock the dynamic C=N bonds in imine-linked covalent organic frameworks (COFs) is highly desired for enhancing their stability and functionality. Herein, a novel C=N bridge locking strategy via rhodium-catalyzed [4+2] annulation is developed to construct nonsubstituted quinoline-linked COFs (NQ-COFs). The notable feature of this strategy includes high C=N conversion efficiency, oxidant-free, and generality for synthesis of a variety of NQ-COFs with high chemical stability. Particularly, after post-synthetic modification, the crystallinity, topology, and porosity of pristine imine-linked COFs are well retained. When used as photocatalysts, NQ-COFs display better visible light absorption and carriers’ separation efficiency due to enhanced in-plane π conjugation ability, as well as more facile generation of superoxide anion radicals than their counterparts, thus leading to efficient synthesis of 2,4,6-tris(aryl)pyridines, benzimidazole, and sulfoxide derivatives.

DOI: 10.1002/anie.202208833

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202208833