A Grafting Hydrogen‐bonded Organic Framework for Benchmark Selectivity of C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> Separation under Ambient Conditions
Furong Yuan, Yunbin Li, Zhen Yuan, Lu Li, Chenxin Chen, Lei He, Hongyu Lin, Xi Fan, Banglin Chen, Shengchang Xiang, Zhangjing Zhang
Abstract
Abstract Reticular chemistry and pore engineering have garnered significant advancements in metal–organic frameworks and covalent organic frameworks, leveraging robust metal‐coordination and covalent bonds. However, these achievements remain elusive in hydrogen‐bonded organic frameworks, hindered by their inherent weakness in hydrogen bonding. Herein, we strategically manipulate the porosity of hydrogen‐bonded frameworks through a grafting approach, culminating in the synthesis of two isomorphic HOFs, HOF‐FJU‐99 and HOF‐FJU‐100, with distinct pore environments. Remarkably, HOF‐FJU‐100, with its microporous architecture, not only showcases exceptional stability but also achieves unparalleled separation efficiency and ultrahigh selectivity for C 2 H 2 /CO 2 mixtures (50/50, v/v) under ambient conditions. Its IAST selectivity value of 201 stands as a benchmark, towering over all previously reported HOFs. The pore of HOF‐FJU‐100 boasts an electrostatic potential highly favourable for C 2 H 2 adsorption, as evidenced by single crystal X‐ray diffraction analysis revealing multiple hydrogen bonding interactions between C 2 H 2 molecules and the framework. In situ gas‐carrier powder X‐ray diffraction analysis underscores the adaptability of pore structure, dynamically adjusting its orientation in response to C 2 H 2 , thereby enabling a highly efficient and specific separation of C 2 H 2 /CO 2 mixtures through specific adsorptive interactions.