Hovorun DM, Voiteshenko IS, Gorb L. Manifestations of intramolecular H-bonds of CH… O and OH… C type in quercetin molecule: Analysis of IR spectra by mean of density functional theory.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023;
287:122065. [PMID:
36356398 DOI:
10.1016/j.saa.2022.122065]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 10/24/2022] [Accepted: 10/29/2022] [Indexed: 06/16/2023]
Abstract
The IR spectra of 48 conformers of quercetin which represent full conformation space of its tautomers have been modeled at B3LYP/6-311++G(d,p) level of the density functional theory. The presence of intramolecular H-bonds C2'H/C6'H…O3 and O3H…C2'/C6' was characterized by their spectral manifestations. The C2'H/C6'H…O3 contacts were found to have a spectral blue-shift. The O3H…C2'/C6' contacts were mostly red-shifted. The stretching vibrations of H-bonds C2'H/C6'H…O3 demonstrate an increase in the intensity of the modes of stretching vibrations ν(C2'H)/ν(C6'H) and an increase in the frequency of their out-of-plane vibrations γ(C2'H)/γ(C6'H). Most of the spectral parameters correlate a little with the energy of the H-bonds.
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