Mobility of the 2-Methylimidazolate Linkers in ZIF-8 Probed by 2H NMR: Saloon Doors for the Guests | Sciact - CRIS-система Института катализа

Mobility of the 2-Methylimidazolate Linkers in ZIF-8 Probed by 2H NMR: Saloon Doors for the Guests Научная публикация

Журнал

The Journal of Physical Chemistry C
ISSN: 1932-7447 , E-ISSN: 1932-7455

Вых. Данные

Год: 2015, Том: 119, Номер: 49, Страницы: 27512-27520 Страниц : 9 DOI: 10.1021/acs.jpcc.5b09312

Ключевые слова

Carboxylation; Crystalline materials; Molecules; Organometallics

Авторы

Kolokolov Daniil I. ^1,2 , Stepanov Alexander G. ^1,2 , Jobic Hervé ³

Организации

1	Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
2	Department of Physical Chemistry, Faculty of Natural Sciences, Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
3	Institut de Recherches sur la Catalyse et l’Environnement de Lyon, CNRS, Universitéde Lyon, 2, Avenue Albert Einstein, 69626 Villeurbanne, France

Информация о финансировании (1)

Российский фонд фундаментальных исследований

14-03-91333

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.

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 CAPlusCA OpenAlex

Полный текст от издателя

Поступила в редакцию:	24 сент. 2015 г.
Опубликована в печати:	10 дек. 2015 г.

Web of science:	WOS:000366339000040
Scopus:	2-s2.0-84949486557
РИНЦ:	26922579
Chemical Abstracts:	2015:1878448
Chemical Abstracts (print):	164:7125
OpenAlex:	W2263677676

БД	Цитирований
Web of science	98
Scopus	100
РИНЦ	100
OpenAlex	105