Selective Gas Uptake and Rotational Dynamics in a (3,24)-Connected Metal–Organic Framework Material

Trenholme, William J.F.; Kolokolov, Daniil I.; Bound, Michelle; Argent, Stephen P.; Gould, Jamie A.; Li, Jiangnan; Barnett, Sarah A.; Blake, Alexander J.; Stepanov, Alexander G.; Besley, Elena; Easun, Timothy L.; Yang, Sihai; Schr�der, Martin

Abstract

The desolvated (3,24)-connected metal-organic framework (MOF) material, MFM-160a, [Cu3(L)(H2O)3] [H6L = 1,3,5-triazine-2,4,6-tris(aminophenyl-4-isophthalic acid)] exhibits excellent high pressure uptake of CO2 (110 wt% at 20 bar, 298 K) and highly selective separation of C2 hydrocarbons from CH4 at 1 bar pressure. Henry’s law selectivities of 79:1 for C2H2:CH4 and 70:1 for C2H4:CH4 at 298 K are observed, consistent with IAST predictions. Significantly, MFM-160a shows a selectivity of 16:1 for C2H2:CO2. Solid state 2H NMR spectroscopic studies on partially deuterated MFM-160-d12 shows an ultra-low barrier to rotation of the phenyl group in the activated MOF (~2 kJ mol-1), and a rotation rate five orders of magnitude slower than usually observed for solid state materials (1.4 x 106 Hz cf. 1011 - 1013 Hz). Upon introduction of CO2 and C2H2 into desolvated MFM-160a, this rate of rotation was found to increase with increas-ing gas pressure, a phenomenon attributed to the weakening of an intramolecular hydrogen bond in the triazine-containing linker upon gas binding. DFT calculations of binding energies and interactions of CO2 and C2H2 around the triazine-core are entirely consistent with the 2H NMR spectroscopic observations.

Citation

Trenholme, W. J., Kolokolov, D. I., Bound, M., Argent, S. P., Gould, J. A., Li, J., …Schröder, M. (2021). Selective Gas Uptake and Rotational Dynamics in a (3,24)-Connected Metal–Organic Framework Material. Journal of the American Chemical Society, 143(9), 3348–3358. https://doi.org/10.1021/jacs.0c11202

• Journal Article Type: Article
• Acceptance Date: Jan 28, 2021
• Online Publication Date: Feb 24, 2021
• Publication Date: Mar 10, 2021
• Deposit Date: Jan 30, 2021
• Publicly Available Date: Feb 25, 2022
• Journal: Journal of the American Chemical Society
• Print ISSN: 0002-7863
• Electronic ISSN: 1520-5126
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 143
• Issue: 9
• Pages: 3348–3358
• DOI: https://doi.org/10.1021/jacs.0c11202
• Keywords: Colloid and Surface Chemistry; Biochemistry; General Chemistry; Catalysis
• Public URL: https://nottingham-repository.worktribe.com/output/5278219
• Publisher URL: https://pubs.acs.org/doi/10.1021/jacs.0c11202
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/jacs.0c11202