Theoretica chimica acta

, Volume 60, Issue 3, pp 283–297 | Cite as

Non-empirical SCF MO studies on the protonation of biopolymer constituents

III. Protonation of cytosine, thymine, and their tautomeric forms
  • Ernst C. Hass
  • Paul G. Mezey
  • János J. Ladik
Original Investigations


Proton affinities of several of the tautomeric forms of cytosine and thymine have been calculated using theab initio Hartree-Fock-Roothaan SCF method. Several of the most stable protonated forms may be obtained by direct protonation from one of the two most stable neutral forms. The calculated total energies do not exclude the possibility of the coexistence of several protonated forms in acidic solutions.

Key words

Protonated cytosine Protonated thymine Tautomeric forms 


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Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Ernst C. Hass
    • 1
  • Paul G. Mezey
    • 1
  • János J. Ladik
    • 2
    • 3
  1. 1.Department of Chemistry and Chemical EngineeringUniversity of SaskatchewanSaskatoonCanada
  2. 2.Chair of Theoretical ChemistryFriedrich-Alexander-University Erlangen-NürnbergFederal Republic of Germany
  3. 3.Laboratory of the National Foundation for Cancer Research, at the Chair of Theoretical ChemistryUniversity of ErlangenNürnbergFederal Republic of Germany

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