Theoretical and Experimental Chemistry

, Volume 26, Issue 2, pp 155–160 | Cite as

Proton phototransfer performance for 2-heteryloxazoles

  • S. I. Druzhinin
  • I. V. Troyanovskii
  • S. A. Krashakov
  • B. M. Uzhinov


Fluorescence spectroscopy has been applied to the photopyrolytic reactions of 2-hetaryloxazoles with acetic acid in ethanol. The reactions occur in the excited state via static and dynamic mechanisms. Various 4-substituted pyridines have similar acid-base parameters in the ground and excited states, which agrees with CNDO/S calculations. The quantum yields, equilibrium constants, and rate constants for these reactions have been determined. The performance factors in proton phototransfer for the 2-hetaryloxazoles are close to one and at least 2.4 times larger than for aza derivatives of aromatic hydrocarbons. The photoreaction and the deactivation induced by it probably involve the same reaction center: the nitrogen atom in the six-membered heterocyclic. A principle of minimum photochemical motion is proposed, in which the quantum performance in the formation of the excited products is inversely related to the change in the system wave function during the reaction. The measurements agree qualitatively with this principle.


Hydrocarbon Pyridine Excited State Nitrogen Atom Quantum Yield 
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Copyright information

© Plenum Publishing Corporation 1990

Authors and Affiliations

  • S. I. Druzhinin
    • 1
  • I. V. Troyanovskii
    • 1
  • S. A. Krashakov
    • 1
  • B. M. Uzhinov
    • 1
  1. 1.Moscow UniversityUSSR

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