Zhang Shu-Yuan, Tang Xi-Hao, Yan Yi-Lun, Li Shu-Qing, Zheng Shengrun, Fan Jun, Li Xinle, Zhang Wei-Guang, Cai Songliang
School of Chemistry, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University, Guangzhou 510006, People's Republic of China.
Department of Chemistry, Clark Atlanta University, Atlanta, Georgia 30314, United States.
ACS Macro Lett. 2021 Dec 21;10(12):1590-1596. doi: 10.1021/acsmacrolett.1c00607. Epub 2021 Nov 24.
Amine-functionalized covalent organic frameworks (COFs) hold great potential in diversified applications. However, the synthesis is dominated by postsynthetic modification, while the de novo synthesis allowing for direct installation of amine groups remains a formidable challenge. Herein, we develop a site-selective synthetic strategy for the facile preparation of amine-functionalized hydrazone-linked COF for the first time. A new monomer 2-aminoterephthalohydrazide (NH-Th) bearing both amine and hydrazide functionalities is designed to react with benzene-1,3,5-tricarbaldehyde (Bta). Remarkably, the different activity of amine and hydrazide groups toward aldehyde underpin the highly site-selective synthesis of an unprecedented NH-Th-Bta COF with abundant free amine groups anchored in the well-defined pore channels. Interestingly, NH-Th-Bta COF exhibits dramatically enhanced iodine uptake capacity (3.58 g g) in comparison to that of the nonfunctionalized Th-Bta COF counterpart (0.68 g g), and many reported porous adsorbents, despite its low specific surface area. Moreover, NH-Th-Bta COF possesses exceptional cycling capability and retained high iodine uptake, even after six cycles. This work not only provides a simple and straightforward route for the de novo synthesis of amine-functionalized COFs but also uncovers the great potential of amine-functionalized COFs as adsorbents in the efficient removal of radioiodine and beyond.
胺功能化共价有机框架（COF）在多种应用中具有巨大潜力。然而，其合成主要通过后合成修饰进行，而能够直接引入胺基的从头合成仍然是一项艰巨的挑战。在此，我们首次开发了一种位点选择性合成策略，用于简便地制备胺功能化腙连接的COF。设计了一种同时带有胺基和酰肼功能的新型单体2-氨基对苯二甲酰肼（NH-Th），使其与苯-1,3,5-三甲醛（Bta）反应。值得注意的是，胺基和酰肼基对醛的不同反应活性支撑了前所未有的NH-Th-Bta COF的高度位点选择性合成，其中大量游离胺基锚定在明确的孔道中。有趣的是，与未功能化的Th-Bta COF对应物（0.68 g/g）以及许多已报道的多孔吸附剂相比，NH-Th-Bta COF的碘吸附容量显著提高（3.58 g/g），尽管其比表面积较低。此外，即使经过六个循环，NH-Th-Bta COF仍具有出色的循环能力并保持高碘吸附量。这项工作不仅为胺功能化COF的从头合成提供了一条简单直接 的途径，还揭示了胺功能化COF作为吸附剂在高效去除放射性碘及其他方面的巨大潜力。
