UID:
(DE-602)edochu_18452_27713
Format:
1 Online-Ressource (5 Seiten)
ISSN:
1433-7851
,
1521-3773
,
1433-7851
,
1521-3773
Content:
The location of Brønsted-acid sites (bridging OH groups, b-OH) at different crystallographic positions of zeolite catalysts influences their reactivity due to varying confinement. Selecting the most stable b-OH conformers at each of the 12 T-sites (T=Si/Al) of H-MFI, a representative set of 26 conformers is obtained which includes free b-OH groups pointing into the empty pore space and b-OH groups forming H-bonds across five- or six-membered rings of TO4 tetrahedra. Chemically accurate coupled-cluster-quality calculations for periodic models show that the strength of internal H-bonds and, hence, the OH bond length vary substantially with the framework position. For 11 of the 19 H-bonded b-OH groups examined, our predictions fall into the full width at half maximum range of the experimental signals at 3250±175 cm−1 and 7.0±1.4 ppm which supports previously debated assignments of these signals to H-bonded b-OH sites.
Content:
Peer Reviewed
In:
Weinheim : Wiley-VCH, 62,25, 1433-7851
In:
1521-3773
Language:
English
DOI:
10.1002/anie.202303204
URN:
urn:nbn:de:kobv:11-110-18452/27713-1
URL:
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