<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Systematic quantum chemical investigation of quercetin and selected eight mono- and bihydroxyflavonols is presented. Structural analysis based on the Density Functional Theory showed that the energetically preferred conformation of flavonols substituted at the C5 and C3 atoms by a hydroxyl group is stabilised via intramolecular hydrogen bonds occurring between the (C4)O···HO(3 or 5) atomic pairs. Depending on the hydroxyl group positions, energetically preferred torsional orientation of the phenyl ring with respect to the planar benzo-γ-pyrone moiety changed from 0 to 180 degrees. Gas-phase electron transitions were investigated using the time-dependent DFT treatment. The dependence of maximal wavelengths on the torsional deformation of the phenyl ring is of a similar shape, i.e. minima observed for the perpendicular orientation and maxima for the planar one. Shape and energies of the Highest Occupied (HOMO) and Lowest Unoccupied (LUMO) Molecular Orbitals were compared. The obtained theoretical results were compared with available experimental data.</p></abstract>

Systematic quantum chemical investigation of quercetin and selected eight mono- and bihydroxyflavonols is presented. Structural analysis based on the Density Functional Theory showed that the energetically preferred conformation of flavonols substituted at the C5 and C3 atoms by a hydroxyl group is stabilised via intramolecular hydrogen bonds occurring between the (C4)O···HO(3 or 5) atomic pairs. Depending on the hydroxyl group positions, energetically preferred torsional orientation of the phenyl ring with respect to the planar benzo-γ-pyrone moiety changed from 0 to 180 degrees. Gas-phase electron transitions were investigated using the time-dependent DFT treatment. The dependence of maximal wavelengths on the torsional deformation of the phenyl ring is of a similar shape, i.e. minima observed for the perpendicular orientation and maxima for the planar one. Shape and energies of the Highest Occupied (HOMO) and Lowest Unoccupied (LUMO) Molecular Orbitals were compared. The obtained theoretical results were compared with available experimental data.

Influence of catecholic ring torsion on hydroxyflavones

Slovak University of Technology in Bratislava

Acta Chimica Slovaca

This work is licensed under the Creative Commons Attribution 4.0 Public License.

{"article-title":"Influence of catecholic ring torsion on hydroxyflavones"}

Systematic quantum chemical investigation of quercetin and selected eight mono- and bihydroxyflavonols is presented. Structural analysis based on the Density...

Influence of catecholic ring torsion on hydroxyflavones

Published Online: Jun 29, 2020

Page range: 49 - 55

DOI: https://doi.org/10.2478/acs-2020-0008

Keywords
BDE, hydroxyflavones, torsion

© 2020 Martin Michalík et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 Public License.

Influence of catecholic ring torsion on hydroxyflavones

Published Online: Jun 29, 2020

Page range: 49 - 55

DOI: https://doi.org/10.2478/acs-2020-0008

KeywordsBDE, hydroxyflavones, torsion

© 2020 Martin Michalík et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 Public License.

Keywords
BDE, hydroxyflavones, torsion