A Two-Way Rod-Packing Indium-Based Nanoporous Metal-Organic Framework for Effective C2/C1 and C2/CO2 Separation

The exploration of reticular chemistry pertaining to rod-packing metal-organic frameworks and the development of solid adsorbents for multitask hydrocarbon separations are two active topics of current research. In this study, an In-organic coordination framework compound denoted ZJNU-121 was assembled from a custom-designed bithiophene-functionalized tetracarboxylate ligand. The title compound not only exhibited a rare two-way rod-packing pattern but also displayed the impressive capability of capturing C2 hydrocarbons from CH4 and CO2 to achieve C2/C1 and C2/CO2 separations. Under ambient con-ditions, the ideal adsorbed solution theory-predicted adsorption selectivities for equimolar mixtures fall in the range of 8.4-13.8 (C2Hn/CH4) and 2.3-3.4 (C2Hn/CO2). Such separation poten-tials were also ascertained by the column breakthrough experiments. Furthermore, the in-depth theoretical insight unveiled the crucial role of active sites such as thiophene sulfur, carboxylate oxygen, and the bridging mu 2-OH group in capturing C2 hydrocarbons in preference to CO2 and CH4. Additionally, the structural integrity of ZJNU-121 can be retained in aqueous solutions with pH values varying from 3 to 11 for 24 h at ambient temperature, as verified by the preservation of PXRD patterns, textural characteristics, and static/dynamic adsorption behaviors. This research not only enriched the architectural diversity of rod MOFs but also reported a robust adsorbent with good application prospects for diversified hydrocarbon separations.

Automated summary

This study explores the reticular chemistry of rod-packing metal-organic frameworks and develops solid adsorbents for multitask hydrocarbon separations. A unique inorganic coordination framework compound, ZJNU-121, was assembled from a specially designed ligand, demonstrating excellent C2/C1 and C2/CO2 separations. The research also investigates the role of active sites and the structural integrity of the framework. This study not only enriches the diversity of metal-organic frameworks but also develops a promising adsorbent for hydrocarbon separations.