A Microporous Hydrogen‐Bonded Organic Framework Based on Hydrogen‐Bonding Tetramers for Efficient Xe/Kr Separation

Abstract

Hydrogen‐bonded organic frameworks (HOFs) have been emerging as a new type of very promising microporous materials for gas separation and purification, but few HOFs structures constructed through hydrogen‐bonding tetramers have been explored in this field. Herein, we report the first microporous HOF (termed as HOF‐FJU‐46) afforded by hydrogen‐bonding tetramers with 4‐fold interpenetrated diamond networks, which shows excellent chemical and thermal stability. What's more, activated HOF‐FJU‐46 exhibits the highest xenon (Xe) uptake of 2.51 mmol g‐1 and xenon/krypton (Kr) selectivity of 19.9 at the ambient condition among the reported HOFs up to date. Dynamic breakthrough tests confirmed the excellent Xe/Kr separation of HOF‐FJU‐46a, showing high Kr productivity (110 mL g‐1) and Xe uptake (1.29 mmol g‐1), as well as good recyclability. The single crystal X‐ray diffraction and the molecular simulations revealed that the abundant accessible aromatic and pyrazole rings in the pore channels of HOF‐FJU‐46a can provide the multiple strong C‐H···Xe interactions with Xe atoms.

Flexible hydrogen-bonded organic frameworks (HOFs): opportunities and challenges

“…This dynamic response allows for interesting changes in pore sizes and shapes to effectively adsorb and separate specific gas molecules. 27,28,38,40–43,45,46,49,51–54,58,60,64,66,67,79–89 In addition, the recyclability of HOFs reduces the cost. The dynamic behavior of flexible HOFs in gas adsorption makes the research more complex than that of other rigid porous materials.…”