The Unimolecular Chemistry of [1, 2-Propanediol]+.: A Rationale in Terms of Hydrogen Bridged Radical Cations

  • Johan K. Terlouw


The low-energy dissociations of radical cations in the gas phase often only occur from isomeric ions generated via extensive rearrangement processes. This is especially true for, but by no means limited to, those ions which have half-lives of > 10”5 s, i.e., the metastable ions which decompose in the drift regions of a mass spectrometer [1]. The quasi-equilibrium theory provides a rationale in that it stipulates that dissociation of metastable ions is strongly dependent on the overall activation energy rather than on the mechanistic complexity of the reaction. Among the many well-documented cases, ionized methyl isobutyrate, (CH3)2CHCOOCH3, provides a classical example [2]. The loss of CH3. from these ions occurs only by C-C cleavage in the isomeric radical cation [CH3CH2CH=C(OH)(OCH3)]+., whose formation involves inter alia a 1, 2 shift of the protonated ester moiety.


Radical Cation Drift Region Appearance Energy Transition State Energy Unimolecular Dissociation 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    for a recent review see: J. L. Holmes, Org. Mass Spectrom. 20, 169 (1985).CrossRefGoogle Scholar
  2. 2.
    E. Göksu, T. Weiske, H. Halim and H. Schwarz, J. Am. Chem. Soc. 106, 1167 (1984).CrossRefGoogle Scholar
  3. 3.
    P. C. Burgers, J. L. Holmes, C. E. C. A. Hop, R. Postma, P. J.A. Ruttink and J. K. Terlouw, J. Am. Chem. Soc. 109, 7315 (1987) and references cited therein.CrossRefGoogle Scholar
  4. 4.
    T.H. Morton, Tetrahedron 38, 3195 (1982).CrossRefGoogle Scholar
  5. 5.
    R. Postma, S. van Helden, J.H. van Lenthe, P.J.A. Ruttink, J.K. Terlouw and J.L. Holmes, Org. Mass Spectrom. 23, in press (1988).Google Scholar
  6. 6a).
    J.K. Terlouw, W. Heerma, P.C. Burgers and J.L. Holmes, Can. J. Chem. 62, 289 (1984).CrossRefGoogle Scholar
  7. 6b).
    R.Postma, P.J.A. Ruttink, F.B. van Duijneveldt, J.K. Terlouw and J.L. Holmes, Can J. Chem. 63, 2798 (1985).CrossRefGoogle Scholar
  8. 7.
    for recent reviews see: a) C. Wesdemiotis and F. W. McLafferty, Chem. Rev. 87, 405 (1987);CrossRefGoogle Scholar
  9. 7.b).
    J. K. Terlouw and H. Schwarz, Angew. Chem. Int. Ed. Engl. 26, 805 (1987).CrossRefGoogle Scholar
  10. 8.
    B. L. M. van Baar, P. C. Burgers, J. L. Holmes and J. K. Terlouw, Org. Mass Spectrom, , submitted for publication.Google Scholar
  11. 9.
    C. Lifshitz, Int. J. Mass Spectrom Ion Phys. 43, 179 (1982) and references cited therein.CrossRefGoogle Scholar
  12. 10.
    for recent references see: a) R. Postma, P. J. A. Ruttink, B. van Baar, J. K. Terlouw, J. L. Holmes and P.C. Burgers, Chem. Phys. Lett. 123, 409 (1986);CrossRefGoogle Scholar
  13. 10b).
    R. Postma, P. J. A. Ruttink, J. K. Terlouw and J. L. Holmes, J. Chem. Soc. Chem. Commun. 1986, 683; c) N. Heinrich and H. Schwarz, Int. J. Mass Spectrom. Ion Proc. 79, 295 (1987); d) see also ref. 5 for a theoretical assessment of the relationship between distonic ions, hydrogen bridged species and ion-dipole complexes in the [CH2=COH/H2O]+ system.Google Scholar

Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • Johan K. Terlouw
    • 1
  1. 1.Analytical Chemistry LaboratoryUtrecht UniversityUtrechtThe Netherlands

Personalised recommendations