Combined matrix-isolation FT-IR and ab-initio 6-31++G** studies on tautomeric properties of nucleic acid bases and simpler model molecules

Linda Houben, Kristien Schoone, Johan Smets, Ludwik Adamowicz, Guido Maes

Research output: Contribution to journalArticle

20 Scopus citations


The combined matrix isolation/ab initio 6-31++G** method is used to study the tautomeric equilibria of purine, 1-CH3-adenine, 3-CH3-adenine and N-CH3-adenine in isolated conditions. For the N9H ⇆ N7H prototropism, tautomeric equilibrium constants of 0.085, 0.090 and 0.005 are obtained for purine, 1-CH3-adenine and N-CH3-adenine, respectively. The other prototropic equilibria that are considered are the amino ⇆ imino tautomerism for which relative amounts of 5.5% for the rare amino form in 1-CH3-adenine and 0.5% for the minor imino tautomer of 3-CH3 adenine were observed, and the N9H ⇆ N3H prototropism where only 0.7% of the experimental spectrum could be accounted for by the presence of the less stable N3H form in N-CH3-adenine.

Original languageEnglish (US)
Pages (from-to)397-401
Number of pages5
JournalJournal of Molecular Structure
StatePublished - Jan 1 1997



  • Ab-initio calculations
  • Adenine
  • Matrix-IR spectroscopy
  • Purine
  • Tautomerism

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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