Li Zixuan, Cai Bingzi, Li Qun, Zhang Di, Liang Yizhao, Liu Yuanyuan, Jiao Yalong, Thomas Arne, Zhao Xiaojia
Hebei Key Laboratory of Inorganic Nano-Materials, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang, Hebei, 050024, China.
Hebei Key Laboratory of Photophysics Research and Application, College of Physics, Hebei Normal University, Shijiazhuang, Hebei, 050024, China.
Angew Chem Int Ed Engl. 2025 Jul 21;64(30):e202509444. doi: 10.1002/anie.202509444. Epub 2025 May 26.
The development of imine-linked covalent organic frameworks (COFs) has also drawn attention to the influence of the nature of imine binding, including its orientation and possible protonation, on the chemical and physical properties of imine COFs. However, the influence of the polarity of imine bond (C═N) on the photocatalytic performance of COFs has not yet been described. In this work, we synthesized a series of imine COFs with differently polarized C═N bonds by altering the C═N bond orientation and regulating the donor-acceptor (D-A) strength, respectively. The less polarized C═N bond for one of the COFs possesses a faster charge separation with a decrease of exciton binding energy (E). In contrast, the imine COF with more polarized C═N bond exhibits a stronger internal electric field contributing to a more efficient charge transfer. Taking into account this trade-off between binding energy and charge transfer concerning the effect of C═N polarity on the photocatalytic performances, the imine COF with moderately polarized C═N bond shows the highest hydrogen evolution performance of 14.0 mmol hg. This work provides evidence that the polarity of C═N should be taken into account when designing and tuning the properties of imine COFs.
亚胺连接的共价有机框架（COFs）的发展也使人们关注到亚胺键合性质，包括其取向和可能的质子化，对亚胺COFs化学和物理性质的影响。然而，亚胺键（C═N）的极性对COFs光催化性能的影响尚未见报道。在这项工作中，我们分别通过改变C═N键取向和调节供体-受体（D-A）强度，合成了一系列具有不同极化程度C═N键的亚胺COFs。其中一种COF的极化程度较低的C═N键具有更快的电荷分离，激子结合能（E）降低。相反，具有更高极化程度C═N键的亚胺COF表现出更强的内电场，有助于更有效的电荷转移。考虑到关于C═N极性对光催化性能影响的结合能和电荷转移之间的这种权衡，具有适度极化C═N键的亚胺COF表现出最高的析氢性能，为14.0 mmol hg。这项工作提供了证据，表明在设计和调节亚胺COFs的性质时应考虑C═N的极性。
