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Applied Magnetic Resonance

, Volume 9, Issue 1, pp 81–102 | Cite as

The sites and dynamics of p-xylene guest molecules in Dianin’s inclusion compound; a deuteron NMR study

  • P. Speier
  • G. Prigl
  • H. Zimmermann
  • U. Haeberlen
  • E. Zaborowski
  • S. Vega
Article

Abstract

Single crystals of Dianin’s inclusion compound with methyl and ring deuterated p-xylene guest molecules were grown and studied by FT deuteron NMR. The spectra from the deuterated methyl groups reveal that these groups reorient rapidly down to 12K; thereafter they enter into the tunneling regime. The rings of the p-xylene guests become motionless whenT reaches 110K. By measuring the orientation dependence of the quadrupole splittings, determining from these data the quadrupole coupling tensors of the ring deuterons and relating these tensors to the C-D bond directions we infer the sites of the p-xylene guests in the cages of Dianin’s inclusion compound. We find two sets of independent sites. Each contains three C3 related individual sites. In each set the population of one of the sites is strongly depleted. The only large-anlge molecular motions are 180° rotational jumps about the long molecular axes. From measurements ofT 1 we conclude that these jumps are thermally activated,τ 0 = 5·10−14 s, ΔE=20 kJ/mol. Additional motions are rapid librations, also about the long molecular axes. Their amplitude increases with increasing temperature, at 300 K it reaches 20°. With 2D-exchange spectra we demonstrate that a p-xylene guest cannot change its site on a timescale of 100 ms and a tempering experiment suggests that this is true on a timescale of several days even atT=371 K.

Keywords

Guest Molecule Quadrupole Splitting Free Induction Decay Molecular Axis Electric Field Gradient Tensor 
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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References

  1. [1]
    Dianin A.P.: J. Russe. Phys. Chem.,46, 1310 (1914)Google Scholar
  2. [2]
    Zaborowski E., Vega S.: Mol. Phys.78, 703 (1993)CrossRefADSGoogle Scholar
  3. [3]
    Flippen J.L., Karle J., Karle I.L.: J. Am. Chem. Soc.92, 3749 (1970)CrossRefGoogle Scholar
  4. [4]
    Tesche B., Zimmermann H., Poupko R., Haeberlen U.: J. Magn. Reson. A104, 68 (1993)CrossRefGoogle Scholar
  5. [5]
    Heuer A., Haeberlen U.: J. Magn. Reson.85, 79 (1989)Google Scholar
  6. [6]
    Frolow F.: private communication 1993.Google Scholar
  7. [7]
    Lalowicz Z.T., Werner U., Müller-Warmuth W.: Z. Naturforsch.43a, 219 (1988)Google Scholar
  8. [8]
    Detken A., Focke P., Zimmermann H., Haeberlen U., Olejniczak Z., Lalowicz Z.T.: Z. Naturforsch., in press.Google Scholar
  9. [9]
    Carrington A., McLachlan A.D.: Introduction to Magnetic Resonance, chap. 12. Harper and Row 1967.Google Scholar
  10. [10]
    Ślósarek G., Heuer A., Zimmermann H., Haeberlen U.: J. Phys.: Condens. Matter1, 5931 (1989)CrossRefADSGoogle Scholar
  11. [11]
    Lipari G., Szabo A.: J. Am. Chem. Soc.104, 4546 (1982)CrossRefGoogle Scholar
  12. [12]
    Schmidt C., Wefing C., Blümich B., Spiess H.W.: Mol. Phys.81, 1239 (1994)CrossRefGoogle Scholar

Copyright information

© Springer 1995

Authors and Affiliations

  • P. Speier
    • 1
  • G. Prigl
    • 1
  • H. Zimmermann
    • 1
  • U. Haeberlen
    • 1
  • E. Zaborowski
    • 2
  • S. Vega
    • 2
  1. 1.Max-Planck-Institut für Medizinische ForschungHeidelbergGermany
  2. 2.The Weizmann Institute of ScienceRehovotIsrael

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