Classical and Non-Classical Decay Paths of Electronically Excited Conjugated Dienes

  • S. Boué
  • D. Rondelez
  • P. Vanderlinden
Conference paper
Part of the The Jerusalem Symposia on Quantum Chemistry and Biochemistry book series (JSQC, volume 10)


In 1969 Oosterhoff and van der Lugt1 investigated the butadiene → cyclobutene interconversion and pointed out that a reaction would take place only if there exist such states from which a driving force can derive ; this was an elegant way of showing on theoretical grounds that a molecule electronically excited in its Franck-Condon nuclear configuration will spontaneously distort itself (relax) if the new nuclear configuration corresponds to an energy minimum which correlates with the initial state along a coordinate devoid of significant barriers. If two electronic states do not correlate with each other (regardless ΔHO) or if they do through an exceedingly high barrier or in a continuous highly endothermic way, no adiabatic interconversion would occur (interconversion does however take place diabatically at avoided surface crossings). According to and within the restrictions of the above statements a molecule, whatever in the ground or in an excited state, is entitled to move on its hypersurface. These motions (changes of internuclear angles and distances) from energy well to energy well are determined by the shape of the potential surfaces; if one were to make any prediction on chemical (or physical) transformations one should obviously have some knowledge of the potential surfaces.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    W.T.A.M. van der Lugt and L.J. Oosterhoff, J. Amer. Chem. Soc., 1969, 91, 6042.CrossRefGoogle Scholar
  2. 2.
    J. Michl, Pure Appl. Chem., 1975, 41, 507 and references cited therein.CrossRefGoogle Scholar
  3. 3.
    L. Salem, J. Amer. Chem. Soc., 1974, 96, 3486.CrossRefGoogle Scholar
  4. 4.
    A. Devaquet, Pure Appl. Chem., 1975, 41, 455.CrossRefGoogle Scholar
  5. 5.
    J.B. Birks, Photophysics of Aromatic Molecules, Wiley- Interscience, 1970, page 247.Google Scholar
  6. 6.
    D. Rondelez and S. Boué, J.C.S. Perkin II, 1976, 647.Google Scholar
  7. 7.
    R. Srinivasan and S. Boue, J. Amer. Chem. Soc., 1971, 93, 550.CrossRefGoogle Scholar
  8. 8.
    P. Vanderlinden and S. Boue, J.C.S. Chem. Comm., 1975, 932.Google Scholar
  9. 9.
    This dismisses the erroneous figure based on a mass balance, which appeared in a preliminary communication8.Google Scholar
  10. 10.
    N. Bigwood and S. Boue, Tetrahedron Letters, 1973, 44, 4311.CrossRefGoogle Scholar
  11. 11.
    S. Boue and R. Srinivasan, J. Amer. Chem. Soc., 1970, 92, 3226.CrossRefGoogle Scholar
  12. 12.
    P. Bruckmann and L. Salem, J. Amer. Chem. Soc., 1976, 96, 5037.CrossRefGoogle Scholar
  13. 13.
    The same scheme would hold as well if two states were formed, one of which decaying exclusively to its initial ground state and the other giving rise to the excimer. This would only change the α and β values but be of no importance to our reasoning; the lowest excimer channel contribution compatible with the numerical figures would involve ~ 3.7% of the excited molecules.Google Scholar
  14. 14.
    L. Salem, J. Amer. Chem. Soc., 1968, 97, 553.CrossRefGoogle Scholar
  15. 15.
    D.F. Eaton, personal communication (PhD thesis, Caltech 19 72 ).Google Scholar
  16. 16.
    J.B. Birks, Organic Molecular Photophysics, J.B. Birks Ed., Wiley-Interscience, 1973, volume 1, page 48.Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1977

Authors and Affiliations

  • S. Boué
    • 1
  • D. Rondelez
    • 1
  • P. Vanderlinden
    • 1
  1. 1.Department of Organic Chemistry ; Physical-Organic Chemistry Grouping ; Faculty of SciencesFree University of BrusselsBrusselsBelgium

Personalised recommendations