Mobility of the 2-Methylimidazolate Linkers in ZIF-8 Probed by 2H NMR: Saloon Doors for the Guests Full article
| Journal |
The Journal of Physical Chemistry C
ISSN: 1932-7447 , E-ISSN: 1932-7455 |
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| Output data | Year: 2015, Volume: 119, Number: 49, Pages: 27512-27520 Pages count : 9 DOI: 10.1021/acs.jpcc.5b09312 | ||||||
| Tags | Carboxylation; Crystalline materials; Molecules; Organometallics | ||||||
| Authors |
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| Affiliations |
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Funding (1)
| 1 | Russian Foundation for Basic Research | 14-03-91333 |
Abstract:
ZIF-8 is one of the most interesting metal-organic frameworks due to its high stability and unique capabilities for hydrocarbons separation. Its porous network is formed by large almost spherical cavities interconnected by very narrow windows ~ 3.4 Å, which should be too small even for methane. At the same time the direct experimental observations show that ZIF-8 cavities are able to host even such large molecules as benzene. This effect is associated with the flexibility of the cavity widows, arising from dynamical freedom on the 2-mIM linkers that form the framework. In this work, by means of the 2H NMR we show that the 2-mIM linkers of the ZIF-8 are very mobile and their mobility is sensitive to the presence of benzene guest. In contrast with other known MOFs based on linearly bonded carboxylates, in guest-free ZIF-8 the plane of 2-mIM linker exhibits 2-site flips within a sector of 2φf = 34○ with very low activation barrier (1.5 kJ mol-1) and high rates (~1012 s-1). Above 380 K the linkers begin to demonstrate additional fast librations with gradually increasing amplitudes γlib comparable with the 2-site flips (γlib = +/-17○ above 560 K). This is a direct evidence that the ZIF-8 linkers twist notably increasing thus the windows aperture sufficiently to fit very large molecules. Upon benzene loading, the geometry of the observed motions remains similar but the potential barrier of the linkers flipping rises up to 9 kJ mol-1.
Cite:
Kolokolov D.I.
, Stepanov A.G.
, Jobic H.
Mobility of the 2-Methylimidazolate Linkers in ZIF-8 Probed by 2H NMR: Saloon Doors for the Guests
The Journal of Physical Chemistry C. 2015.
V.119. N49. P.27512-27520. DOI: 10.1021/acs.jpcc.5b09312
WOS
Scopus
РИНЦ
ANCAN
OpenAlex
Mobility of the 2-Methylimidazolate Linkers in ZIF-8 Probed by 2H NMR: Saloon Doors for the Guests
The Journal of Physical Chemistry C. 2015.
V.119. N49. P.27512-27520. DOI: 10.1021/acs.jpcc.5b09312
WOS
Scopus
РИНЦ
ANCAN
OpenAlex
Files:
Full text from publisher
Dates:
| Submitted: | Sep 24, 2015 |
| Published print: | Dec 10, 2015 |
Identifiers:
| Web of science: | WOS:000366339000040 |
| Scopus: | 2-s2.0-84949486557 |
| Elibrary: | 26922579 |
| Chemical Abstracts: | 2015:1878448 |
| Chemical Abstracts (print): | 164:7125 |
| OpenAlex: | W2263677676 |