TY - JOUR
T1 - Dynamics of Linkers in Metal-Organic Framework Glasses
AU - Khudozhitkov, Alexander E.
AU - Ogiwara, Naoki
AU - Donoshita, Masaki
AU - Kobayashi, Hirokazu
AU - Stepanov, Alexander G.
AU - Kolokolov, Daniil I.
AU - Kitagawa, Hiroshi
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/5/15
Y1 - 2024/5/15
N2 - Metal-organic framework (MOF) glasses have emerged as a new class of organic-inorganic hybrid glass materials. Considerable efforts have been devoted to unraveling the macroscopic dynamics of MOF glasses by studying their rheological behavior; however, their microscopic dynamics remain unclear. In this work, we studied the effect of vitrification on linker dynamics in ZIF-62 by solid-state 2H nuclear magnetic resonance (NMR) spectroscopy. 2H NMR relaxation analysis provided a detailed picture of the mobility of the ZIF-62 linkers, including local restricted librations and a large-amplitude twist; these details were verified by molecular dynamics. A comparison of ZIF-62 crystals and glasses revealed that vitrification does not drastically affect the fast individual flipping motions with large-amplitude twists, whereas it facilitates slow cooperative large-amplitude twist motions with a decrease in the activation barrier. These observations support the findings of previous studies, indicating that glassy ZIF-62 retains permanent porosity and that short-range disorder exists in the alignment of ligands because of distortion of the coordination angle.
AB - Metal-organic framework (MOF) glasses have emerged as a new class of organic-inorganic hybrid glass materials. Considerable efforts have been devoted to unraveling the macroscopic dynamics of MOF glasses by studying their rheological behavior; however, their microscopic dynamics remain unclear. In this work, we studied the effect of vitrification on linker dynamics in ZIF-62 by solid-state 2H nuclear magnetic resonance (NMR) spectroscopy. 2H NMR relaxation analysis provided a detailed picture of the mobility of the ZIF-62 linkers, including local restricted librations and a large-amplitude twist; these details were verified by molecular dynamics. A comparison of ZIF-62 crystals and glasses revealed that vitrification does not drastically affect the fast individual flipping motions with large-amplitude twists, whereas it facilitates slow cooperative large-amplitude twist motions with a decrease in the activation barrier. These observations support the findings of previous studies, indicating that glassy ZIF-62 retains permanent porosity and that short-range disorder exists in the alignment of ligands because of distortion of the coordination angle.
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U2 - 10.1021/jacs.3c13156
DO - 10.1021/jacs.3c13156
M3 - Article
C2 - 38693778
AN - SCOPUS:85192224312
SN - 0002-7863
VL - 146
SP - 12950
EP - 12957
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 19
ER -