Intermolecular interactions in AST zeolites through 14N NMR and DFT calculations.
Acta Crystallogr C Struct Chem
; 73(Pt 3): 202-207, 2017 Mar 01.
Article
em En
| MEDLINE
| ID: mdl-28257014
ABSTRACT
The structure of the silica AST zeolites (octadecasil) synthesized in fluoride medium using tetramethylammonium (TMA) as the organic structure-directing agent has been reinvestigated using 14N NMR quadrupolar parameters and DFT calculations. The value of the experimental 14N quadrupolar coupling constant (CQ = 27â
kHz) is larger than expected for a TMA cation possessing a high degree of motion. The analysis of a DFT-optimized octadecasil cluster along with the comparison between measured and calculated 14N NMR parameters demonstrate the presence of weak C-H...O hydrogen bonds between the TMA in the [46612] cages and the silica skeleton. These intermolecular interactions can be related to the presence of Si...F tetrel bonds within the [46] cages. These new results provide additional information with regard to the formation mechanisms and structure of the octadecasil zeolites.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Acta Crystallogr C Struct Chem
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
França