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Ab‐initio sto‐3 G energy of tautomerism for uracil
Author(s) -
Zielinski Theresa Julia,
Shibata Masayuki,
Rein Robert
Publication year - 2009
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.560160733
Subject(s) - tautomer , uracil , ab initio , chemistry , ionization energy , computational chemistry , ab initio quantum chemistry methods , ionization , molecule , stereochemistry , organic chemistry , ion , dna , biochemistry
Ab‐initio sto‐3 G energies for uracil (U) and the tautomer 4‐hydroxyuracil (U*) are reported. The four highest occupied molecular orbital energies for uracil correlate with experimental photoelectron ionization potentials with a least‐squares linear correlation coefficient of 0.999. The energy Δ E t for U ⇋ U* using the best available geometries is 25.5 kcal/mole. The reaction field continuum model for the solvent effect indicates that Δ E t may be lowered by approximately 3 kcal/mole. Therefore the diketo form of uracil is theoretically determined to be the most stable form in solution as well as in the gas phase, in complete agreement with experiment.