title: 129Xe NMR study of the framework flexibility of the porous hybrid MIL-53(Al).
abstract: The metal-organic framework MIL-53 exhibits a structural transition between two possible porous structures, so-called large-pore (lp) and narrow-pore (np) forms, depending on the temperature or when guest molecules are adsorbed. (129)Xe NMR has been used to study the lp --> np transition induced by the adsorption of xenon as revealed by the adsorption isotherms. The NMR spectra show that the two structures, characterized by two distinct lines, coexist for xenon pressures above 5 x 10(4) Pa at room temperature, but a complete transformation is achieved when the temperature is decreased. An original interpretation of the NMR results allowed us to quantify the rate of the structural transformation. In particular, at room temperature, we have shown that 28% of the channels remain open. Two possible interpretations of the hysteresis observed in the chemical shift variation versus xenon pressure are proposed.
authors.affiliation: Laboratoire de Chimie de la Matière Condensée, UMR CNRS 7574, Université Pierre et Marie Curie, Univ. Paris 06, F 75252 Paris Cedex 05, France. marie-anne.springuel-huet@upmc.fr
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Springuel-Huet
authors.forename: Andrei
authors.initials: A
authors.lastname: Nossov
authors.forename: Ziad
authors.initials: Z
authors.lastname: Adem
authors.forename: Flavien
authors.initials: F
authors.lastname: Guenneau
authors.forename: Christophe
authors.initials: C
authors.lastname: Volkringer
authors.forename: Thierry
authors.initials: T
authors.lastname: Loiseau
authors.forename: Gérard
authors.initials: G
authors.lastname: Férey
authors.forename: Antoine
authors.initials: A
authors.lastname: Gédéon
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000737:chemistry*; D016062:Porosity; D014979:Xenon Isotopes / Q000737:chemistry
chemical_list: D009942:Organometallic Compounds; D014979:Xenon Isotopes; D000535:Aluminum