Micropores in crystalline dipeptides as seen from the crystal structure, He pycnometry, and ¹²⁹Xe NMR Spectroscopy

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DOIResolve DOI: http://doi.org/10.1021/ja060474j
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TypeArticle
Journal titleJACS: Journal of the American Chemical Society
ISSN00027863
Volume128
Issue20
Pages67376744; # of pages: 8
AbstractEight crystalline dipeptides were studied: AV (Ala-Val), VA (Val-Ala), AI (Ala-Ile), VV (Val-Val), IA (Ile-Ala), IV (Ile-Val), VI (Val-Ile), and LS (Leu-Ser) (all LL isomers). The first seven form an isostructural series (space group P6₁), whereas LS has a different structure (P6₅). All structures display H-bonded tubular assemblies of the dipeptide molecules resulting in open ultramicropores in the form of isolated one-dimensional (1D) channels. The total porosity of the materials ranges from 4 to 12% (micropore volume from 0.04 to 0.12 cm³/g). Calculations based on the crystal structures, He pycnometry, and solid-state ¹²⁹Xe NMR methods were used to obtain a comprehensive description of the geometry and properties of the micropores. The following order was established for the channel diameter: AV > VA > AI > VV > IA > IV > VI, with >5 Å for AV and <4 Å for VI; LS is close to AI. The observed sorption behavior cannot be described adequately based on the crystal structure and can only be understood if one takes into account the dynamics of the host matrix. The pores are chiral, with the center of the channel describing a right-handed helix (left-handed for LS). The following order was established for the channel helicity: VA > IA > IV > AV ≈ AI ≈ VV > VI > LS, with a helix diameter of ~2 Å for VA, IA, and IV and ~1 Å or less for the remaining dipeptides. A comparison of the dipeptides studied with other supramolecular materials is given and the potential for applications is discussed.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada; NRC Steacie Institute for Molecular Sciences
Peer reviewedNo
Identifier10072378
NPARC number12327298
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Record identifier45ff06b5-4c04-4624-b0aa-bf3be600dba7
Record created2009-09-10
Record modified2016-05-09
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