Zhang Jie, Zhou Wenwen, Zhao Jianfeng, Xu Liangliang, Jiang Xuekai, Li Zhiwen, Peng Yongwu, Li Gao
Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, 230601, China.
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
Small. 2025 Jan;21(1):e2408324. doi: 10.1002/smll.202408324. Epub 2024 Nov 3.
Olefin-linked covalent organic frameworks (OL-COFs) show great promise for visible-light-driven photocatalysis. Manipulating atomic-level donor-acceptor interactions in OL-COFs is key to understanding their exciton effects in this system. Here, three OL-COFs are presented with orthorhombic lattice structures, synthesized via Knoevenagel polycondensation reaction of terephthalaldehyde and tetratopic monomers featuring phenyl, benzo[c][1,2,5]oxadiazole, and benzo[c][1,2,5]thiadiazole moieties. These OL-COFs feature tunable donor-acceptor interactions, making them ideal for studying exciton effects in olefin-linked systems. Comprehensive analyses, including temperature-dependent photoluminescence spectra, ultrafast spectroscopy, and theoretical calculations, reveal that stronger donor-acceptor interactions lead to reduced exciton binding energy (E), accelerated exciton dissociation, and longer-lived photogenerated charges, thereby enhancing photocatalytic performance. Notably, The TMO-BDA COF, with the lowest E, demonstrates superior photocatalytic activity in one-pot sequential organic transformation and excellent catalytic performance in gram-scale reactions, highlighting its potential for practical applications. This work provides valuable insights into regulating the exciton effect at the molecular level in OL-COFs, offering pathways to enhance photocatalytic efficiency.
烯烃连接的共价有机框架（OL-COFs）在可见光驱动的光催化方面展现出巨大潜力。在OL-COFs中调控原子级供体-受体相互作用是理解该体系中激子效应的关键。在此，展示了三种具有正交晶格结构的OL-COFs，它们通过对苯二甲醛与含有苯基、苯并[c][1,2,5]恶二唑和苯并[c][1,2,5]噻二唑部分的四官能团单体进行克诺文纳格尔缩聚反应合成。这些OL-COFs具有可调节的供体-受体相互作用，使其成为研究烯烃连接体系中激子效应的理想材料。包括温度相关光致发光光谱、超快光谱和理论计算在内的综合分析表明，更强的供体-受体相互作用会导致激子结合能（E）降低、激子解离加速以及光生电荷寿命延长，从而提高光催化性能。值得注意的是，具有最低E的TMO-BDA COF在一锅多步有机转化中表现出优异的光催化活性，在克级反应中展现出出色的催化性能，突出了其实际应用潜力。这项工作为在分子水平上调控OL-COFs中的激子效应提供了有价值的见解，为提高光催化效率提供了途径。
