Analysis of IR Spectra and Hydrogen Bonds of Uracil and N1,N3-deuterouracil

The in-plane vibrations and IR spectrum intensities of monomeric uracil and N1,N3-deuterouracil and their associates in the polycrystalline state were calculated and analyzed in the valence-optical approximation of vibration theory. The obtained data on the variations of the parameters of the molecular models is used to analyze hydrogen bonds. It is shown that in the polycrystalline state uracil forms hydrogen bonds of two types: bonds involving N–H groups (C4=O...HN1, C4=O...HN3) and those involving the C–H group (C2=O...HC5).