Issue 26, 2020

Self-adjusting binding pockets enhance H2 and CH4 adsorption in a uranium-based metal–organic framework

Abstract

A new, air-stable, permanently porous uranium(IV) metal–organic framework U(bdc)2 (1, bdc2− = 1,4-benzenedicarboxylate) was synthesized and its H2 and CH4 adsorption properties were investigated. Low temperature adsorption isotherms confirm strong adsorption of both gases in the framework at low pressures. In situ gas-dosed neutron diffraction experiments with different D2 loadings revealed a rare example of cooperative framework contraction (ΔV = −7.8%), triggered by D2 adsorption at low pressures. This deformation creates two optimized binding pockets for hydrogen (Qst = −8.6 kJ mol−1) per pore, in agreement with H2 adsorption data. Analogous experiments with CD4 (Qst = −24.8 kJ mol−1) and N,N-dimethylformamide as guests revealed that the binding pockets in 1 adjust by selective framework contractions that are unique for each adsorbent, augmenting individual host–guest interactions. Our results suggest that the strategic combination of binding pockets and structural flexibility in metal–organic frameworks holds great potential for the development of new adsorbents with an enhanced substrate affinity.

Graphical abstract: Self-adjusting binding pockets enhance H2 and CH4 adsorption in a uranium-based metal–organic framework

Supplementary files

Article information

Article type
Edge Article
Submitted
27 apr 2020
Accepted
27 may 2020
First published
27 may 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2020,11, 6709-6716

Self-adjusting binding pockets enhance H2 and CH4 adsorption in a uranium-based metal–organic framework

D. P. Halter, R. A. Klein, M. A. Boreen, B. A. Trump, C. M. Brown and J. R. Long, Chem. Sci., 2020, 11, 6709 DOI: 10.1039/D0SC02394A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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