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Local Structure of Cationic Sites in Dehydrated Zeolites Inferred from 27Al Magic-Angle Spinning NMR and Density Functional Theory Calculations. A Study on Li-, Na-, and K-Chabazite
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SYSNO ASEP 0460633 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Local Structure of Cationic Sites in Dehydrated Zeolites Inferred from 27Al Magic-Angle Spinning NMR and Density Functional Theory Calculations. A Study on Li-, Na-, and K-Chabazite Author(s) Klein, Petr (UFCH-W) RID, ORCID
Pashkova, Veronika (UFCH-W) RID, ORCID
Thomas, Haunani M. (UFCH-W)
Whittleton, Sarah R. (UFCH-W)
Brus, Jiří (UMCH-V) RID, ORCID
Kobera, Libor (UMCH-V) RID, ORCID
Dědeček, Jiří (UFCH-W) RID, ORCID
Sklenák, Štěpán (UFCH-W) RID, ORCID, SAISource Title Journal of Physical Chemistry C. - : American Chemical Society - ISSN 1932-7447
Roč. 120, č. 26 (2016), s. 14216-14225Number of pages 10 s. Language eng - English Country US - United States Keywords zeolites ; density functional theory ; NMR spectroscopy Subject RIV CF - Physical ; Theoretical Chemistry Subject RIV - cooperation Institute of Macromolecular Chemistry - Macromolecular Chemistry R&D Projects GA15-13876S GA ČR - Czech Science Foundation (CSF) GA15-14007S GA ČR - Czech Science Foundation (CSF) Institutional support UFCH-W - RVO:61388955 ; UMCH-V - RVO:61389013 UT WOS 000379457000039 EID SCOPUS 84978027691 DOI 10.1021/acs.jpcc.6b04391 Annotation High-resolution 27Al magic-angle spinning (MAS) NMR spectroscopy of dehydrated M-forms (M = Li, Na, and K) of chabazite in tandem with density functional theory calculations are employed to study the quadrupolar interaction of 27Al nuclei in dehydrated zeolites and to understand the corresponding high-resolution 27Al MAS NMR spectra. We show that the broadening of the 27Al NMR signal in dehydrated zeolites occurs predominantly because of the deformation of the local structure of AlO4– tetrahedra caused by the binding of M+ to the zeolite framework. This deformation increases with the decreasing diameter of the cations from K+ to Li+. The influence of water in hydrated zeolites is limited only to prevent a strong coordination of the M+ cation to O atoms of the AlO4– tetrahedron, but there is no “averaging” effect concerning the local electrostatic field due to molecular motion of water molecules. Our results show that the 27Al NMR parameters in dehydrated zeolites can be calculated accurately enough to allow the description of the local structure of AlO4– tetrahedra in dehydrated zeolites and to infer the local structure of the sites accommodating the extraframework M+ cations. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2017
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