An Adaptive Metal–Organic Framework Discriminates Xylene Isomers by Shape‐Responsive Deformation

Published

December 4, 2024

Author(s)

Jiaqi Li, Bin Sheng, Rundao Chen, Hui Wu, Wei Zhou, Fang Zheng, Baojian Liu, Qiwei Yang, Zhiguo Zhang, Yiwen Yang, Qilong Ren, Zongbi Bao

Abstract

The separation of xylene isomers, especially para-xylene, is a crucial but challenging process in the chemical industry due to their similar molecular dimensions. Here, a flexible metal–organic framework, Ni(ina)2, (ina = isonicotinic acid) is employed to effectively discriminate xylene isomers. The adsorbent with adaptive deformation accommodates the shapes of isomer molecules, thereby translating their subtle shape differences into characteristic framework deformation energies. Through a combination of multiple local flexibility behaviors, Ni(ina)2 exhibits guest-specific structural transformations that energetically favor para-xylene over other isomers. Single-crystal X-ray diffraction, in situ powder X-ray diffraction, and theoretical investigations validate this "adaptive fitting" mechanism, where the degree of structural deformation scales with the mismatch between the molecular shape and pore geometry. As a result, Ni(ina)2 achieves exceptional para-xylene selectivity in both liquid and vapor phase separations, maintaining a high para-xylene purity and productivity. This work demonstrates a novel strategy of exploiting framework flexibility to address challenging molecular separations and provides fresh insights into the design of selective adsorbents.

Citation

Advanced Materials

Volume

37

Issue

5

Pub Type

Journals

Download Paper

https://doi.org/10.1002/adma.202413506

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Citation

Li, J. , Sheng, B. , Chen, R. , Wu, H. , Zhou, W. , Zheng, F. , Liu, B. , Yang, Q. , Zhang, Z. , Yang, Y. , Ren, Q. and Bao, Z. (2024), An Adaptive Metal–Organic Framework Discriminates Xylene Isomers by Shape‐Responsive Deformation, Advanced Materials, [online], https://doi.org/10.1002/adma.202413506, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=960480 (Accessed July 20, 2025)