Gu Xiaoling, Niu Hongyun, Sun Qing, Jiang Shaodong, Shi Yali, Cai Yaqi
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing 100085, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Appl Mater Interfaces. 2025 Jan 15;17(2):3818-3828. doi: 10.1021/acsami.4c19765. Epub 2025 Jan 3.
Vinylene-linked Covalent Organic Frameworks (V-2D-COFs) are a class of promising porous organic materials that feature fully π-conjugated structures, high crystallinity, ultrahigh chemical stability, and extraordinary optoelectronic properties. However, the types of reactions and the availability of monomers for synthesizing linked COFs are considerably limited by the irreversibility of the C═C bond, and the complete π-conjugated structure restricts their in-depth research in hydrophilicity, membrane materials, and proton conductivity. Postsynthetic modification (PSM), which can avoid these problems by incorporating functional moieties into the predetermined framework, provides an alternative way to construct diverse V-2D-COFs. Herein, we report a general strategy to introduce C-C, C-S-C, and functional groups into -COFs via the thiol-ene click reaction. To demonstrate the universality of this approach, we synthesized two COFs (COF-CN and COF-1), and subsequently introduced six different types of thiol compounds at their skeletal C═C sites. The quantitative yield was confirmed by X-ray Photoelectron Spectroscopy (XPS) and cross-polarization magic angle spinning C NMR spectroscopy. This thiol-ene click modification of vinylene-linked COFs at skeletal C═C sites allows for flexible structural design, providing these COFs with new linkages (C-C and C-S-C) that are otherwise difficult to produce directly. Thus, it facilitates precise modulation of their properties, such as photophysical properties, hydrophilicity, and proton conductivity, promising a diverse range of compelling applications for the future.
亚乙烯基连接的共价有机框架（V-2D-COFs）是一类很有前景的多孔有机材料，具有完全π共轭结构、高结晶度、超高化学稳定性和非凡的光电性能。然而，由于C═C键的不可逆性，用于合成连接COFs的反应类型和单体可用性受到很大限制，并且完整的π共轭结构限制了它们在亲水性、膜材料和质子传导性方面的深入研究。后合成修饰（PSM）通过将功能基团引入预定框架来避免这些问题，为构建多样化的V-2D-COFs提供了一种替代方法。在此，我们报道了一种通过硫醇-烯点击反应将C-C、C-S-C和官能团引入-COFs的通用策略。为了证明这种方法的通用性，我们合成了两种COFs（COF-CN和COF-1），随后在它们的骨架C═C位点引入了六种不同类型的硫醇化合物。通过X射线光电子能谱（XPS）和交叉极化魔角旋转C NMR光谱证实了定量产率。这种在骨架C═C位点对亚乙烯基连接的COFs进行硫醇-烯点击修饰允许灵活的结构设计，为这些COFs提供了难以直接产生的新连接（C-C和C-S-C）。因此，它有助于精确调节它们的性质，如光物理性质、亲水性和质子传导性，有望在未来实现各种引人注目的应用。
