Applied Magnetic Resonance

, Volume 9, Issue 1, pp 45–59 | Cite as

A study of the dynamic equilibrium between symmetrical and distorted 1,2,3-trimethylcyclohexane radical cations

  • M. Lindgren
  • N. P. Benetis
  • M. Matsumoto
  • M. Shiotani
Article
Received:
Revised:

Abstract

Radical cations of the 1,2,3-trimethylcyclohexane isomers stabilized in various γ-irradiated solute/halocarbon matrices have been investigated by means of ESR in the temperature range 4–77K. At 4 K the ESR spectra are dominated by contributions from an asymmetrically distorted structure with the unpaired electron localized to the C1-C2 bond. On increasing the temperature a reversible change occurs in the ESR line-shape of the cations of the two symmetrical isomers. Using a two-site jump model to reproduce the temperature dependent line-shape, the phenomenon is explained in terms of an interconversion between two such distorted structures, each being the mirror image of the other. The Arrhenius plot associated with the process is markedly nonlinear towards the low temperature region. The experimental data are also modelled by postulating that another (different) electronic ground state, having higher symmetry, becomes populated with the increase of temperature. In this way, the spectral changes can be simulated using a three-site jump model which couple the thermally activated two-site jump process (E a ca. 0.137 kcal/mol) with a dynamical equilibrium between the asymmetrical ground state and a symmetrical structure 0.058 kcal/mol higher in energy. The energy barrier to pass from the distorted to the symmetrical structure was evaluated to be 0.085 kcal/mol.

Keywords

Radical Cation Arrhenius Plot Electronic Ground State Methyl Group Rotation Trans Decalin 
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.
This is a preview of subscription content, log in to check access.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    Shida T., Nosaka Y., Kato T.: J. Phys. Chem.82, 695–698 (1978)CrossRefGoogle Scholar
  2. [2]
    Smith I.G., Symons M.C.R.: J. Chem. Res. (S)1979, 382–383.Google Scholar
  3. [3]
    Wang T., Williams F.: J. Phys. Chem.84, 3156–3159 (1980)CrossRefGoogle Scholar
  4. [4]
    Iwasaki M., Toriyama K., Nunome K.: J. Am. Chem. Soc.103, 359 3592 (1981)Google Scholar
  5. [5]
    Lund A., Shiotani M. (Eds): Radical Ionic Systems. Kluwer 1991.Google Scholar
  6. [6]
    Huang M.B., Lunell S., Lund A.: Chem. Phys. Lett.99, 201–205 (1983)CrossRefADSGoogle Scholar
  7. [7]
    Lunell S., Huang M.B., Claesson O., Lund A.: J. Chem Phys.82, 5121–5126 (1985)CrossRefADSGoogle Scholar
  8. [8]
    Ohta K., Nakatsuji H., Kubodera H., Shida T.: Chem. Phys.76, 271–281 (1983)CrossRefGoogle Scholar
  9. [9]
    Iwasaki M., Toriyama K., Nunome K.: J. Chem. Soc., Chem. Commun.1983, 202–204.Google Scholar
  10. [10]
    Toriyama K., Nunome K., Iwasaki M.: J. Chem. Soc., Chem. Commun.1984, 143–145.Google Scholar
  11. [11]
    Lunell S., Huang M.B., Lund A.: Faraday Discuss. Chem. Soc.78, 35–47 (1984)CrossRefGoogle Scholar
  12. [12]
    Shiotani M., Ohta N., Ichikawa T.: Chem. Phys. Lett.149, 185–190 (1988)CrossRefADSGoogle Scholar
  13. [13]
    Lindgren M., Shiotani M., Ohta N., Ichikawa T., Sjöqvist L.: Chem. Phys. Lett.161, 127–132 (1989)CrossRefADSGoogle Scholar
  14. [14]
    Shiotani M., Lindgren M., Ichikawa T.: J. Am. Chem. Soc.112, 967–973 (1990)CrossRefGoogle Scholar
  15. [15]
    Shiotani M., Lindgren M., Ohta N., Ichikawa T.: J. Chem. Soc., Perkin. Trans. 21991, 711–719.Google Scholar
  16. [16]
    Sjöqvist L., Lindgren M., Shiotani M.: J. Chem. Soc., Faraday. Trans.86, 3377–3382 (1990)CrossRefGoogle Scholar
  17. [17]
    Shiotani M., Lindgren M., Takahashi F., Ichikawa T.: Chem. Phys. Lett.170, 201–205 (1990)CrossRefADSGoogle Scholar
  18. [18]
    Lindgren M., Matsumoto M., Shiotani M.: J. Chem. Soc., Perkin Trans. 21992, 1397–1402.Google Scholar
  19. [19]
    Shiotani M., Matsumoto M., Lindgren M.: J. Chem. Soc., Perkin Trans. 21993, 1995–2002.Google Scholar
  20. [20]
    Shiotani M., Komaguchi K., Ohshita J., Ishikawa M., Sjöqvist L.: Chem. Phys. Lett.188, 93–99 (1992)CrossRefADSGoogle Scholar
  21. [21]
    Komaguchi K., Shiotani M., Ishikawa M., Sasaki K.: Chem. Phys. Lett.200, 580–586 (1992)CrossRefADSGoogle Scholar
  22. [22]
    Geoffroy M., Kispert L.D., Hwang J.S.: J. Chem. Phys.70, 4238–4242 (1979)CrossRefADSGoogle Scholar
  23. [23]
    See, e.g.: Tachikawa H., Hokari H., Yoshida H.: J. Phys. Chem.97, 10035–10041 (1993), and references therein.CrossRefGoogle Scholar
  24. [24]
    Melekov V.I., Anisimov O.A., Sjöqvist L., Lund A.: Chem. Phys. Lett.174, 95–102 (1990)CrossRefADSGoogle Scholar
  25. [25]
    Barnabas M.V., Trifunac A.D.: Chem. Phys. Lett.187, 565–570 (1991)CrossRefADSGoogle Scholar
  26. [26]
    PC-version kindly provided from T. Bally, University of Fribourg, Switzerland. Original program described by: Schmelzer A., Haselbach E.: Helv. Chim. Acta54, 1299 (1971)Google Scholar
  27. [27]
    QCPE Program No. 506.Google Scholar
  28. [28]
    Sears T., Miller T.A., Bondybey V.E.: J. Chem. Phys.72, 6070–6085 (1980)CrossRefADSGoogle Scholar
  29. [29]
    Benetis N.P., Schneider D.J., Freed J.H.: J. Magn. Reson.85, 275–293 (1989)Google Scholar
  30. [30]
    Benetis N.P., Lindgren M., Lee H.-S., Lund A.: Appl. Magn. Reson.1, 267–281 (1990)CrossRefGoogle Scholar
  31. [31]
    Benetis N.P., Sjöqvist L., Lund A., Maruani J.: J. Magn. Reson.95, 523–535 (1991)Google Scholar
  32. [32]
    Sjöqvist L., Benetis N.P., Lund A., Maruani J.: Chem. Phys.156, 457–464 (1991)CrossRefGoogle Scholar
  33. [33]
    Lindgren M., Erickson R., Benetis N.P., Antzutkin O.N.: J. Chem. Soc., Perkin Trans. 21993, 2009–2014.Google Scholar
  34. [34]
    Antzutkin O.N., Benetis N.P., Lindgren M., Lund A.: Chem. Phys.169, 195–202 (1993)CrossRefGoogle Scholar
  35. [35]
    Heinzer J.: Mol. Phys.22, 167 (1971); QCPE (Quantum Chemistry Program Exchange) Program No.207. Indiana University 1972.CrossRefADSGoogle Scholar

Copyright information

© Springer 1995

Authors and Affiliations

  • M. Lindgren
    • 1
  • N. P. Benetis
    • 1
  • M. Matsumoto
    • 2
  • M. Shiotani
    • 2
  1. 1.Department of Physics and Measurement TechnologyLinköping University of TechnologyLinköpingSweden
  2. 2.Department of Applied Physics and Chemistry, Faculty of EngineeringHiroshima UniversityHigashi HiroshimaJapan

Personalised recommendations