Coronene-uracil complexes embedded in argon matrices: FTIR spectroscopy and quantum-mechanical calculations

S. G. Stepanian, A. Yu Ivanov, V. A. Karachevtsev, L. Adamowicz

Research output: Contribution to journalArticlepeer-review

Abstract

We employ low-temperature matrix-isolation FTIR spectroscopy and quantum chemical calculations to study the interaction between nucleobase uracil and coronene which models the graphene surface. To observe the dimer FTIR spectrum, we use a quartz microbalance that allows us to produce matrix samples with precisely determined concentrations of coronene and uracil (with the concentration ratio of 2.5:1:1000 for coronene:uracil:argon). The interaction between coronene and uracil results in spectral shifts of uracil spectral bands. These shifts do not exceed 10 cm–1. The maximum shifts are observed for the C=O stretching and NH out-of-plane vibrations of uracil. The structures and interaction energies of stacked and H-bonded coronene-uracil complexes are calculated at the DFT/B3LYP(GD3BJ)/aug-cc-pVDZ and MP2/aug-cc-pVDZ levels of theory. In total, 19 stable stacked and two H-bonded coronene-uracil dimer structures are found in the calculations. The interaction energy obtained for the most stable stacked dimer is – 12.1 and – 14.3 kcal/mol at the DFT and MP2 levels, respectively. The interaction energies of the H-bonded dimers do not exceed – 3 kcal/mol. The IR spectra of the studied monomeric molecules and of all the dimers are calculated at the DFT/B3LYP(GD3BJ)/aug-cc-pVDZ level of theory. The spectral shifts of the most stable stacked coronene-uracil dimer obtained in the calculations are in good agreement with the experimental results.

Original languageEnglish (US)
Pages (from-to)355-364
Number of pages10
JournalFizika Nizkikh Temperatur
Volume47
Issue number4
StatePublished - Apr 2021

Keywords

  • Coronene
  • FTIR spectroscopy
  • Low-temperature matrix isolation
  • Stacking
  • Uracil

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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