title: Investigating the Interaction of Water Vapour with Aminopropyl Groups on the Surface of Mesoporous Silica Nanoparticles.
abstract: The interaction of water molecules with the surface of hybrid silica-based mesoporous materials is studied by29Si,1H and13C solid-state NMR and IR spectroscopy, with the support of ab initio calculations. The surface of aminopropyl-grafted mesoporous silica nanoparticles is studied in the dehydrated state and upon interaction with controlled doses of water vapour. Former investigations described the interactions between aminopropyl and residual SiOH groups; the present study shows the presence of hydrogen-bonded species (SiOH to NH2) and weakly interacting "free" aminopropyl chains with restricted mobility, together with a small amount of protonated NH3+groups. The concentration of the last-named species increased upon interaction with water, and this indicates reversible and fast proton exchange from water molecules to a fraction of the amino groups. Herein, this is discussed and explained for the first time, by a combination of experimental and theoretical approaches.
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica and Centro Nano-SiSTeMI, Università del Piemonte Orientale, A. Avogadro, Via T. Michel 11, 15121, Alessandria, Italy.
authors.forename: Geo
authors.initials: G
authors.lastname: Paul
authors.affiliation: Università di Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125, Torino, Italy.
authors.forename: Giorgia Elena
authors.initials: GE
authors.lastname: Musso
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica and Centro Nano-SiSTeMI, Università del Piemonte Orientale, A. Avogadro, Via T. Michel 11, 15121, Alessandria, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Bottinelli
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica and Centro Nano-SiSTeMI, Università del Piemonte Orientale, A. Avogadro, Via T. Michel 11, 15121, Alessandria, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cossi
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica and Centro Nano-SiSTeMI, Università del Piemonte Orientale, A. Avogadro, Via T. Michel 11, 15121, Alessandria, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Marchese
authors.affiliation: Università di Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125, Torino, Italy.
authors.forename: Gloria
authors.identifier: http://orcid.org/0000-0001-7720-3584
authors.initials: G
authors.lastname: Berlier
keywords: NMR spectroscopy; density functional calculations; hydration; mesoporous materials; surface chemistry