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

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 & sdot;& sdot;& sdot;Xe interactions with Xe atoms. The first example of microporous hydrogen-bonded organic framework, HOF-FJU-46, based on hydrogen- bonding tetramers that is self-assembled from tetrahedral building block tetrakis(4-(1H-pyrazol-4-yl) phenyl) silane was reported. The activated HOF-FJU-46 shows highly efficient separation of Xe/Kr mixture with the highest Xe uptake and IAST selectivity among the reported HOFs up to date.image

Automated summary

This article reports the structure of a new type of microporous material, hydrogen-bonded organic frameworks (HOFs), with a 4-fold interpenetrated diamond network structure, which exhibits excellent chemical and thermal stability. The activated HOF-FJU-46 shows the highest xenon uptake and xenon/krypton selectivity among the reported HOFs to date.