Chen Zi-Ao, Zou Lei, Cao Rong, Huang Yuan-Biao
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Natl Sci Rev. 2025 Jan 24;12(3):nwaf032. doi: 10.1093/nsr/nwaf032. eCollection 2025 Mar.
The features of intrinsic porosity and fluidity endow porous liquids (PLs) with unique properties and performance but the preparation of PLs remains challenging due to the difficulty in liquefying and keeping porous features at the same time. Herein, we develop a stepwise surface functionalization and ion exchange strategy to achieve a rare example of flexible covalent organic framework (COF)-based PL (COF-PLs). By coating the outer surface of the judiciously selected three-dimensional flexible COF-301 with an imidazolium salt corona, followed by liquefaction using the anion canopy potassium poly(ethylene glycol) sulfonate (PEGS) via electrostatic interactions, a flexible PL, COF-301-PL, can be obtained. Theoretical calculations and CO adsorption experiments reveal that the cavities of COF-301-PL undergo dynamic adjustments in response to changes in CO pressure. The dynamic expansion effect can not only provide additional gas adsorption capacity (7.04 mmol/g at 40 bar) but also facilitate the mass transfer of gas molecules during the catalytic process. Consequently, COF-301-PL exhibits superior catalytic efficiency for the conversion of CO into cyclic carbonate by a factor of 24 and 17 compared to those of PEGS and COF-301 solid counterpart, respectively. The optimization of substrate adsorption and mass transfer conditions consequently improves the overall efficiency of catalytic reactions. This work offers a new perspective on the preparation of PLs and their great potential application for gas adsorption and catalysis.
本征孔隙率和流动性的特性赋予了多孔液体（PLs）独特的性质和性能，但由于难以同时实现液化和保持多孔特性，PLs的制备仍然具有挑战性。在此，我们开发了一种逐步表面功能化和离子交换策略，以实现基于柔性共价有机框架（COF）的PL（COF-PLs）这一罕见实例。通过用咪唑鎓盐冠层包覆精心选择的三维柔性COF-301的外表面，然后通过静电相互作用使用阴离子冠层聚（乙二醇）磺酸钾（PEGS）进行液化，可获得柔性PL，即COF-301-PL。理论计算和CO吸附实验表明，COF-301-PL的空腔会响应CO压力的变化而进行动态调整。这种动态膨胀效应不仅可以提供额外的气体吸附容量（40 bar下为7.04 mmol/g），还能在催化过程中促进气体分子的传质。因此，与PEGS和COF-301固体对应物相比，COF-301-PL在将CO转化为环状碳酸酯的反应中分别表现出高24倍和17倍的优异催化效率。底物吸附和传质条件的优化从而提高了催化反应的整体效率。这项工作为PLs的制备及其在气体吸附和催化方面的巨大潜在应用提供了新的视角。
