title: Microporous Molecular Materials from Dipeptides Containing Non-proteinogenic Residues.
abstract: Dipeptides with two hydrophobic side chains have proved to be an exceptional source of microporous organic materials, but since previous structures were limited to the incorporation of only proteinogenic residues, their full potential as adsorbents has remained unexplored. Single-crystal XRD data for ten new compounds with non-proteinogenic L-2-aminobutanoic acid and/or L-2-amino-pentanoic acid are presented. The gas-phase accessibility of their crystal pores, with cross-sections of 2.3 to 5.1 Å, was monitored by CO2 and CH4 adsorption isotherms. Included CO2 was also detected spectroscopically by 2D MAS NMR. An extensive conformational analysis reveals that the use of linear rather than branched side chains (such as L-valine and L-isoleucine) affords peptides with a greater degree of conformational freedom and yields more-flexible channel surfaces that may easily adapt to a series of potential guest molecules.
authors.affiliation: Department of Chemistry, University of Oslo, P.O.Box 1033 Blindern, 0315 Oslo (Norway).
authors.forename: Vitthal N
authors.initials: VN
authors.lastname: Yadav
authors.affiliation: Department of Materials Science, University of Milano Biocca, Via R. Cozzi 55, 20125 Milano (Italy). comotti@mater.unimib.it.
authors.forename: Angiolina
authors.initials: A
authors.lastname: Comotti
authors.affiliation: Department of Materials Science, University of Milano Biocca, Via R. Cozzi 55, 20125 Milano (Italy).
authors.forename: Piero
authors.initials: P
authors.lastname: Sozzani
authors.affiliation: Department of Materials Science, University of Milano Biocca, Via R. Cozzi 55, 20125 Milano (Italy).
authors.forename: Silvia
authors.initials: S
authors.lastname: Bracco
authors.affiliation: Department of Chemistry, University of Oslo, P.O.Box 1033 Blindern, 0315 Oslo (Norway).
authors.forename: Tore
authors.initials: T
authors.lastname: Bonge-Hansen
authors.affiliation: Department of Chemistry, University of Oslo, P.O.Box 1033 Blindern, 0315 Oslo (Norway).
authors.forename: Martin
authors.initials: M
authors.lastname: Hennum
authors.affiliation: Department of Chemistry, University of Oslo, P.O.Box 1033 Blindern, 0315 Oslo (Norway). c.h.gorbitz@kjemi.uio.no.
authors.forename: Carl Henrik
authors.initials: CH
authors.lastname: Görbitz
mesh_terms: D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D016062:Porosity
chemical_list: D004151:Dipeptides
keywords: X-ray diffraction; bioorganic chemistry; crystal engineering; microporous materials; peptides