title: Structure of nanochannel entrances in stopcock-functionalized zeolite L composites.
abstract: Multifunctional hybrid materials are obtained by modifying zeolite L (ZL) with stopcock molecules, consisting of a tail group that can enter the ZL nanochannels and a head group too large to pass the channel opening. However, to date no microscopic-level structural information on modified ZL materials has been reported. Herein we draw atomistic pictures of channel openings and stopcock-functionalized ZL based on first-principles calculations. We elucidate the interactions of the tail group with the inner surface of ZL channels and the space-filling properties of the stopcocks, revealing cork- or lid-sealing modes. Water is essential to obtain stable modifications. AlOH groups are the preferred modification sites, bipodal modifications suffer from strain, and tripod binding is ruled out. Our results suggest the viability of recursive functionalization by cross-linking.
authors.affiliation: Department of Science and High Technology, University of Insubria and INSTM, Via Valleggio 9, 22100 Como (Italy).
authors.forename: Gloria
authors.initials: G
authors.lastname: Tabacchi
authors.affiliation: Department of Science and High Technology, University of Insubria and INSTM, Via Valleggio 9, 22100 Como (Italy). ettore.fois@uninsubria.it.
authors.forename: Ettore
authors.initials: E
authors.lastname: Fois
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland). gion.calzaferri@dcb.unibe.ch.
authors.forename: Gion
authors.initials: G
authors.lastname: Calzaferri
keywords: density functional calculations; interfaces; nanostructures; supramolecular chemistry; zeolites