武汉大学汪成团队报道了柔性三维共价有机框架中气体触发的门开启效应。相关研究成果于2024年4月14日发表于国际顶尖学术期刊《美国化学会杂志》。

由于新型软多孔晶体 (SPCs) 在气体储存和分离中的应用前景广阔，开发能够从无孔晶体转化为多孔晶体的新型软多孔晶体具有重要意义。

该文中，研究人员首次系统地研究了具有柔性构建块的，三维共价有机框架（3D-COFs）的气体触发栅极打开行为。FCOF-5是一种在主链中含有C–O单键的3D COF，对各种气体（如CO₂、C₂和C₃碳氢化合物）具有独特的“S形”等温线。根据原位表征，由于框架中柔性C–O单键的旋转，FCOF-5经历了压力诱导的从闭合到开放的结构转变。

此外，FCOF-5的门控滞后吸附特性可以使其用作吸收剂，有效地从C₃H₄/C₃H₆混合物中去除C₃H₄。因此，由柔性构建块合成的3D COFs代表了一种具有门开启特性的新型SPC。

该项研究将有力地启发我们设计其他基于3D COF的SPCs，以供未来有趣的应用。

附：英文原文

Title: Gas-Triggered Gate-Opening in a Flexible Three-Dimensional Covalent Organic Framework

Author: Xiaoling Liu, Zhifang Wang, Ya Zhang, Na Yang, Bo Gui, Junliang Sun, Cheng Wang

Issue&Volume: April 14, 2024

Abstract: The development of novel soft porous crystals (SPCs) that can be transformed from nonporous to porous crystals is significant because of their promising applications in gas storage and separation. Herein, we systematically investigated for the first time the gas-triggered gate-opening behavior of three-dimensional covalent organic frameworks (3D COFs) with flexible building blocks. FCOF-5, a 3D COF containing C–O single bonds in the backbone, exhibits a unique “S-shaped” isotherm for various gases, such as CO2, C2, and C3 hydrocarbons. According to in situ characterization, FCOF-5 undergoes a pressure-induced closed-to-open structural transition due to the rotation of flexible C–O single bonds in the framework. Furthermore, the gated hysteretic sorption property of FCOF-5 can enable its use as an absorbent for the efficient removal of C3H4 from C3H4/C3H6 mixtures. Therefore, 3D COFs synthesized from flexible building blocks represent a new type of SPC with gate-opening characteristics. This study will strongly inspire us to design other 3D COF-based SPCs for interesting applications in the future.

DOI: 10.1021/jacs.4c01331

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c01331