Analysis of vibrational spectra of some new E- and Z-4-arylidene-3- isochromanones: Part 2. Isomers and conformers of the 2′-pyrrolyl and 2′-nitrophenyl derivatives

Gábor Keresztury, Sándor Holly, Krisztina István, Tom Sundius, Tamás Lóránd

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3 Citations (Scopus)

Abstract

The infrared and Raman spectra of resolved E and Z isomers of some 4-arylidene-3-isochromanone derivatives were analyzed with the aim of pointing out the differences in vibrational behavior of their coexisting stable conformers. Quantum mechanical (QM) density functional (DFT/B3LYP/6-31*) and normal coordinate calculations were carried out to establish the equilibrium structures and to facilitate the interpretation of the vibrational spectra of the 2′-pyrrolyl and 2′-nitrophenyl derivatives. The frequencies and intensities calculated according to the scaled quantum mechanical (SQM) force field method were used to simulate the IR and Raman spectra and compare them to the measured ones. The results demonstrate that the adopted methodology is capable of treating these fairly large polycyclic molecules. The resulting spectral simulations and detailed vibrational description can be highly useful in clarifying spectral differences brought about by cis-trans isomerism and indicating the extent of spectral changes due to further conformational changes of the aryl substituent attached to the olefinic C=C bond.

Original languageEnglish
Pages (from-to)107-118
Number of pages12
JournalJournal of biochemical and biophysical methods
Volume61
Issue number1-2 SPEC. ISS.
DOIs
Publication statusPublished - Oct 29 2004

Keywords

  • Conformers
  • DFT
  • Isochromanones
  • Isomerism
  • SQM force field
  • Vibrational spectra

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry

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