Solid-state NMR spectroscopy proves the presence of penta-coordinated Sc sites in MIL-100(Sc)
Abstract
Advanced solid-state NMR methods and first-principles calculations demonstrate for the first time the formation of penta-coordinated scandium sites. These coordinatively unsaturated sites were shown during the thermal activation of scandium-based metal-organic frameworks (MOFs). A 45Sc NMR experiment allows their specific observation in activated Sc3BTB2 (H3BTB=1,3,5-tris(4-carboxyphenyl)benzene) and MIL-100(Sc) MOFs. The assignment of the ScO5 groups is supported by the DFT calculations of NMR parameters. The presence of ScO5 Lewis acid sites in MIL-100(Sc) explains furthermore its catalytic activity. The first NMR experiment to probe 13C−45Sc distances is also introduced. This advanced solid-state NMR pulse sequence allows the demonstration of the shrinkage of the MIL-100(Sc) network when the activation temperature is raised.
Citation
Giovine , R , Volkringer , C , Ashbrook , S E , Trébosc , J , McKay , D , Loiseau , T , Amoureux , J-P , Lafon , O & Pourpoint , F 2017 , ' Solid-state NMR spectroscopy proves the presence of penta-coordinated Sc sites in MIL-100(Sc) ' , Chemistry - A European Journal , vol. 23 , no. 40 , pp. 9525-9534 . https://doi.org/10.1002/chem.201700584
Publication
Chemistry - A European Journal
Status
Peer reviewed
ISSN
1521-3765Type
Journal article
Description
Chevreul Institute (FR 2638), Ministère de l′Enseignement Supérieur et de la Recherche, Région Hauts-de-France, and FEDER are acknowledged for supporting and partially funding this work. Authors are also grateful for funding supported by contract ANR-14-CE07-0009-01.Collections
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