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Applied Magnetic Resonance

, Volume 3, Issue 5, pp 779–795 | Cite as

Hindered motions in a ketonea-urea inclusion compound. An ESR and ENDOR study

  • F. Bonon
  • M. Brustolon
  • A. L. Maniero
  • U. Segre
Article

Abstract

We have studied by ESR and ENDOR spectroscopy the free radicals produced in γ-irradiated inclusion compound formed between the ketone 10-nonadecanone and urea. Only one type of long lived radical is formed by the removal of an α-proton from the ketone. The hyperfine (hf) coupling constants of the α- and β-protons of the radicals have been measured by ESR at different temperatures in the range 110–292 K and at different orientations of the crystals. The hf coupling of the γ-protons of the radical and of the urea protons have been studied by ENDOR. The temperature and angular dependences of the coupling constants have been analyzed in terms of the internal and overall motions of the radical inside the hexagonal channels formed by the urea molecules. It has been found that the radical cannot perform complete reorientations around the long molecular axis, but it undergoes restricted rotational diffusion. This process is explained by assuming a coupling between the rotational and translational degrees of freedom of the radical inside the urea channels.

Keywords

Clathrate Guest Molecule Inclusion Compound ENDOR Spectrum ENDOR Line 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Wien 1992

Authors and Affiliations

  • F. Bonon
    • 1
  • M. Brustolon
    • 1
  • A. L. Maniero
    • 1
  • U. Segre
    • 2
  1. 1.Dipartimento di Chimica FisicaUniversità di PadovaPadovaItaly
  2. 2.Dipartimento di ChimicaUniversità di ModenaModenaItaly

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