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Melting of Low Molecular Weight Compounds in Confinement Observed by ²H-Solid State NMR: Biphenyl, a Case Study

Sousa Amadeu, Nader de ; Grünberg, Bob ; Frydel, Jarek ; Werner, Mayke ; Limbach, Hans-Heinrich ; Breitzke, Hergen ; Buntkowsky, Gerd (2021)
Melting of Low Molecular Weight Compounds in Confinement Observed by ²H-Solid State NMR: Biphenyl, a Case Study.
In: Zeitschrift für Physikalische Chemie, 2012, 226 (11-12)
doi: 10.26083/tuprints-00019687
Article, Secondary publication, Publisher's Version

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Item Type: Article
Type of entry: Secondary publication
Title: Melting of Low Molecular Weight Compounds in Confinement Observed by ²H-Solid State NMR: Biphenyl, a Case Study
Language: English
Date: 2021
Place of Publication: Darmstadt
Year of primary publication: 2012
Publisher: De Gruyter
Journal or Publication Title: Zeitschrift für Physikalische Chemie
Volume of the journal: 226
Issue Number: 11-12
DOI: 10.26083/tuprints-00019687
Corresponding Links:
Origin: Secondary publication service
Abstract:

The ²H-NMR solid echo spectra of biphenyl molecules as guests in the mesopores of neat and silylated SBA-15 have been measured as a function of temperature. At low temperatures typical ²H-Pake patterns with parameters of (Qzz = 132 kHz, corresponding to Qcc = 176 kHz) and (η = 0.04) are observed. All samples exhibit a strong reduction of the melting point from the bulk value of 342.4 K to values between 222 K and 229 K, depending on both the pore diameter and the surface state and a glass like behavior of the biphenyl molecules in the melting regime. Employing the Roessler two-phase model of the modeling of glass-transitions by ²H-solid state NMR the distribution of activation energies for the rotational motions has been determined. At temperatures closely below the glass-transition temperature deviations from a static Pake pattern of an aromatic deuteron are observed, which indicate a pre-melting motion of biphenyl, which could be caused by C₂-ring flips of the phenyl rings.

Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-196879
Classification DDC: 500 Science and mathematics > 540 Chemistry
Divisions: 07 Department of Chemistry > Eduard Zintl-Institut > Physical Chemistry
Date Deposited: 01 Oct 2021 11:29
Last Modified: 14 Aug 2023 07:56
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/19687
PPN: 51058909X
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