DOI: 10.1073/pnas.63.2.253. EXCITED-STATE TWO-PROTON TAUTOMERISM IN HYDROGEN-BONDED N-HETEROCYCLIC BASE PAIRS

EXCITED-STATE TWO-PROTON TAUTOMERISM IN HYDROGEN-BONDED N-HETEROCYCLIC BASE PAIRS

10.1073/pnas.63.2.253

Crossref journal-article

Proceedings of the National Academy of Sciences

Proceedings of the National Academy of Sciences (341)

Abstract

The optical absorption and luminescence spectra of 7-azaindole and its doubly hydrogen-bonded dimer were investigated as a model for the study of electronic interactions in DNA base pairs. It is demonstrated that a biprotonic phototautomerism occurs in the dimer and in suitable ethanol solvates in fluid solvents but that the phenomenon is not observed in a rigid solvent matrix. The normal violet structured fluorescence of 7-azaindole monomer becomes a broad green fluorescence in the tautomer. It is shown that spectral band interchanges, excimer formation, excited-state single-proton transfer, and proton tunneling cannot account for the luminescence change, but that the molecular exciton effect facilitates the cooperative two-proton reversible transfer. It is proposed that biprotonic phototautomerism with molecular environmental sensitivity could provide a mechanism for the initial step in ultraviolet mutagenic effects in DNA.

Bibliography

Taylor, C. A., El-Bayoumi, M. A., & Kasha, M. (1969). EXCITED-STATE TWO-PROTON TAUTOMERISM IN HYDROGEN-BONDED N-HETEROCYCLIC BASE PAIRS. Proceedings of the National Academy of Sciences, 63(2), 253â260.

Authors 3

Carl Al Taylor (first)
M. Ashraf El-Bayoumi (additional)
Michael Kasha (additional)

References 0 Referenced 371

None

Dates

Type	When
Created	19 years, 3 months ago (May 31, 2006, 2:13 a.m.)
Deposited	3 years, 4 months ago (April 13, 2022, 10:02 a.m.)
Indexed	3 days, 11 hours ago (Aug. 29, 2025, 6:23 a.m.)
Issued	56 years, 3 months ago (June 1, 1969)
Published	56 years, 3 months ago (June 1, 1969)
Published Online	56 years, 3 months ago (June 1, 1969)
Published Print	56 years, 3 months ago (June 1, 1969)

Funders 0

None

BibTeX

@article{Taylor_1969, title={EXCITED-STATE TWO-PROTON TAUTOMERISM IN HYDROGEN-BONDED N-HETEROCYCLIC BASE PAIRS}, volume={63}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.63.2.253}, DOI={10.1073/pnas.63.2.253}, number={2}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Taylor, Carl Al and El-Bayoumi, M. Ashraf and Kasha, Michael}, year={1969}, month=jun, pages={253–260} }

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