Investigation of frequency coupling in the IR spectra of 4H-pyrido(1,2a)pyrimidin-4-one derivatives

G. Horaváth, M. Pongor-Csákvári, A. I. Kiss, G. Fogarasi, P. Pulay

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The IR spectra of 4H-pyrido(1,2a)pyrimidin-4-one derivatives have been investigated in solid state and different solvents, at different temperatures. The experimental data of several keto-ester derivatives with an ester group in position 3 suggest coupling of the CO stretching frequencies. The CO band of higher frequency is more intense, the separation being 30-80 cm-1. The force constants of the CO bonds have been calculated by the CNDO/2 method. The results of computation are in good accordance with the experimental data: the frequency separation arises mainly from the different CO vibrations, the intensities can be explained only by frequency coupling.

Original languageEnglish
Pages (from-to)2293-2297
Number of pages5
Issue number17
Publication statusPublished - 1977


ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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