Matrix-isolation FT-IR study and theoretical calculations of the vibrational, tautomeric and H-bonding properties of hypoxanthine

R. Ramaekers, G. Maes, Ludwik Adamowicz, A. Dkhissi

Research output: Contribution to journalArticle

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Abstract

The neutral compound hypoxanthine is investigated using the technique of matrix-isolation FT-IR spectroscopy combined with density functional theory (DFT) and ab initio methods. Two theoretical methods (RHF and DFT/B3-LYP) are compared for vibrational frequency prediction, and four methods (RHF//RHF, MP2//RHF, DFT//DFT and MP2//DFT) for prediction of the relative energies of the tautomers and the interaction energies of the complexes. All the possible tautomeric forms have been considered theoretically, and the results indicate that two oxo forms (O17 and O19) and one hydroxy form (H9-rl) are the three most stable forms. The experimental FT-IR spectra are consistent with this prediction, and nearly all the characteristic spectral features of these forms have been identified in the spectrum. A theoretical study of the H-bonded complexes of these three tautomers with water is also performed. Several structures have been found for each form and the results demonstrate that the closed complexes with two H-bonds are the most stable systems due to the H-bond cooperative effect.

Original languageEnglish (US)
Pages (from-to)205-221
Number of pages17
JournalJournal of Molecular Structure
Volume560
Issue number1-3
DOIs
StatePublished - Jan 29 2001

Fingerprint

Hypoxanthine
Density functional theory
isolation
Theoretical Models
density functional theory
matrices
tautomers
predictions
Spectrum Analysis
Vibrational spectra
Water
Infrared spectroscopy
energy
water
spectroscopy
interactions

Keywords

  • Ab initio calculations
  • Density functional theory calculations
  • H-bonding
  • Matrix-isolation FT-IR spectroscopy
  • Tautomerism

ASJC Scopus subject areas

  • Structural Biology
  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Spectroscopy
  • Atomic and Molecular Physics, and Optics

Cite this

Matrix-isolation FT-IR study and theoretical calculations of the vibrational, tautomeric and H-bonding properties of hypoxanthine. / Ramaekers, R.; Maes, G.; Adamowicz, Ludwik; Dkhissi, A.

In: Journal of Molecular Structure, Vol. 560, No. 1-3, 29.01.2001, p. 205-221.

Research output: Contribution to journalArticle

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