title: 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). A45Sc 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 ScO5groups is supported by the DFT calculations of NMR parameters. The presence of ScO5Lewis acid sites in MIL-100(Sc) explains furthermore its catalytic activity. The first NMR experiment to probe13C-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.
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.
authors.forename: Raynald
authors.initials: R
authors.lastname: Giovine
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.|Institut Universitaire de France, 1 rue Descartes, 75231, Paris Cedex 5, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Volkringer
authors.affiliation: EaStCHEM and School of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife, KY16 9ST, UK.
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Ashbrook
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Trébosc
authors.affiliation: EaStCHEM and School of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife, KY16 9ST, UK.
authors.forename: David
authors.initials: D
authors.lastname: McKay
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Loiseau
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.|Bruker, Biospin, Wissembourg, France.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Amoureux
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.|Institut Universitaire de France, 1 rue Descartes, 75231, Paris Cedex 5, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lafon
authors.affiliation: Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181-UCCS, Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.
authors.forename: Frédérique
authors.identifier: http://orcid.org/0000-0001-7537-7142
authors.initials: F
authors.lastname: Pourpoint
keywords: 13C−45Sc; MIL-100(Sc); ScO5; density functional calculations; metal-organic frameworks