A Solid-State Transformation of Hydrogen-Bonded Organic Frameworks for Efficient Acetylene Storage and Gas Separation
Youlie Cai, Yanchun Zheng, Yiqi Chen, Runzhi Wei, Hui Xu, Junkuo Gao
Abstract
High Resolution Image Download MS PowerPoint Slide Developing robust microporous hydrogen-bonded organic frameworks (HOFs) is crucial for exploring novel physical adsorbents and revealing the structure–property relationship of hydrogen-bonding pairing behaviors. However, it is still challenging to obtain dense and stable hydrogen-bonded frameworks due to the rigidity and spatial resistance of the tectonic centers. Herein, we report a robust microporous HOF (HOF-ZSTU-4) via 4,4′,4′,4″-([1,1′-biphenyl]-4,4′-diylbis(azanetriyl))tetrabenzoic acid (H 4 BDATB) with flexible nitrogen nodes composing the tectonic center. Single-crystal X-ray diffraction (SCXRD) analysis shows that the activated framework undergoes a solid-to-solid phase transition because of the torsion of the carboxyl–carboxyl dimer, leading to the switching of the framework from the sql topology to the cds topology (HOF-ZSTU-4a). The single-component gas sorption isotherm reveals that HOF-ZSTU-4a has a C 2 H 2 packing density of 0.54 kg L –1, marking it as the most efficient among reported HOFs. In addition, HOF-ZSTU-4a exhibits promising separation selectivity for several binary gas mixtures, and the dynamic separation performance for C 2 H 2 /CO 2, CO 2 /N 2, and CH 4 /N 2 is verified by dynamic breakthrough experiments.