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Title: NMR relaxation and exchange in metal-organic frameworks for surface area screening

Abstract

We describe a robust screening technique that correlates the surface area of metal organic frameworks to the proton T-2 relaxation behavior of imbibed solvent at low field (13 MHz). In frameworks with small pore sizes (<1 nm) or strong solvent-framework interactions, diffusional exchange between the pore-confined and inter-particle solvent populations remains slow compared to the T-2 of the pore-confined solvent, allowing for a direct porosity analysis of the T-2 spectrum obtained from Laplace inversions. Increases in framework pore-size (>1 nm) lead to corresponding increases in the rate of solvent exchange, as confirmed by T-2 relaxation exchange (REXSY) experiments; increases in the pore size also increases the T-2 of the pore-confined solvent. The combination of these two effects results in comparable rates of relaxation and exchange, which precludes the direct analysis of Laplace inversions. Thus, two- and three-site kinetics models were applied to extract porosity from relaxation decays, thereby improving the utility of the porosity screening tool. (C) 2014 Elsevier Inc. All rights reserved.

Authors:
; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1211090
DOE Contract Number:  
DE- AR0000103
Resource Type:
Journal Article
Resource Relation:
Journal Name: Microporous and Mesoporous Materials; Journal Volume: 205
Country of Publication:
United States
Language:
English

Citation Formats

Chen, JJ, Mason, JA, Bloch, ED, Gygi, D, Long, JR, and Reimer, JA. NMR relaxation and exchange in metal-organic frameworks for surface area screening. United States: N. p., 2015. Web. doi:10.1016/j.micromeso.2014.07.037.
Chen, JJ, Mason, JA, Bloch, ED, Gygi, D, Long, JR, & Reimer, JA. NMR relaxation and exchange in metal-organic frameworks for surface area screening. United States. doi:10.1016/j.micromeso.2014.07.037.
Chen, JJ, Mason, JA, Bloch, ED, Gygi, D, Long, JR, and Reimer, JA. Sun . "NMR relaxation and exchange in metal-organic frameworks for surface area screening". United States. doi:10.1016/j.micromeso.2014.07.037.
@article{osti_1211090,
title = {NMR relaxation and exchange in metal-organic frameworks for surface area screening},
author = {Chen, JJ and Mason, JA and Bloch, ED and Gygi, D and Long, JR and Reimer, JA},
abstractNote = {We describe a robust screening technique that correlates the surface area of metal organic frameworks to the proton T-2 relaxation behavior of imbibed solvent at low field (13 MHz). In frameworks with small pore sizes (<1 nm) or strong solvent-framework interactions, diffusional exchange between the pore-confined and inter-particle solvent populations remains slow compared to the T-2 of the pore-confined solvent, allowing for a direct porosity analysis of the T-2 spectrum obtained from Laplace inversions. Increases in framework pore-size (>1 nm) lead to corresponding increases in the rate of solvent exchange, as confirmed by T-2 relaxation exchange (REXSY) experiments; increases in the pore size also increases the T-2 of the pore-confined solvent. The combination of these two effects results in comparable rates of relaxation and exchange, which precludes the direct analysis of Laplace inversions. Thus, two- and three-site kinetics models were applied to extract porosity from relaxation decays, thereby improving the utility of the porosity screening tool. (C) 2014 Elsevier Inc. All rights reserved.},
doi = {10.1016/j.micromeso.2014.07.037},
journal = {Microporous and Mesoporous Materials},
number = ,
volume = 205,
place = {United States},
year = {Sun Mar 15 00:00:00 EDT 2015},
month = {Sun Mar 15 00:00:00 EDT 2015}
}