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Tautomerism of pyrimidine bases—uracil, cytosine, isocytosine: Theoretical study with complete optimization of geometry
Author(s) -
Czermiński R.,
Lesyng B.,
Pohorille A.
Publication year - 1979
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560160315
Subject(s) - tautomer , mindo , uracil , energy minimization , cytosine , computational chemistry , pyrimidine , chemistry , thymine , ionization energy , mndo , ground state , dipole , ionization , atomic physics , physics , stereochemistry , dna , molecule , organic chemistry , ion , biochemistry
The semiempirical MINDO /3 method with complete optimization of geometry is employed to calculate the electronic ground‐state properties (dipole moments and ionization potentials) and the energies of various tautomeric forms of uracil, uracil monoanion, cytosine, and isocytosine. The results are shown to be consistent with most of the experimental data. Accuracy of various quantum–mechanical methods is discussed. Particular attention is paid to the influence of the geometry optimization on energy differences between various tautomers. Some qualitative conclusions of biological importance are drawn from these calculations.