On the ground-state tautomerization of 3-hydroxyflavone

Dzugan, T. P.; Schmidt, J. A.; Aartsma, Thijs J.

doi:10.1016/0009-2614(86)80292-5

Cited by 46 publications

(28 citation statements)

References 12 publications

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“…According to previous IR results, 15 The Raman spectra of 3-HF have been considered in more detail in previous studies. 34,35 To facilitate comparison with the other molecules, we have abstracted some of the results here.…”

Section: -Hydroxyflavonementioning

confidence: 99%

“…16 -20 Unlike in flavone where the carbonyl absorption is at 1649 cm 1 , in 3-HF its wavenumber is lowered to 1610 cm 1 which overlaps with the C C band. The IR spectra in the C-H and O-H stretching region were reported differently in various works, 10,15,16 in which researchers concluded that there is no strong hydrogen bonding in 3-HF, as opposed to the 5-hydroxyflavone (5-HF) molecule. The hydroxyl stretching absorption was found at 3350 cm 1 .…”

Section: Introductionmentioning

confidence: 99%

“…10,15,21 -23 The published IR spectra show that although in 5-HF the hydroxyl stretching band is broadened and displaced to lower wavenumbers (3000-2500 cm 1 ) to an extent that it has almost disappeared, none of the compounds examined shows a marked lowering of the carbonyl wavenumber. 15 Common bands in the 1400-1000 cm 1 region have also been studied. Carbonyl IR absorptions of 5-HF on KBr disk, Nujol mull, CCl 4 and dioxane solution were reported at 1653, 1651, 1652 and 1654 cm 1 , respectively.…”

Section: Introductionmentioning

confidence: 99%

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Raman and surface‐enhanced Raman spectra of flavone and several hydroxy derivatives

Teslova

Corredor

Livingstone

et al. 2007

J Raman Spectroscopy

105

114

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The Raman and surface-enhanced Raman spectra (SERS) of flavone and three of its hydroxy derivatives, 3-hydroxyflavone (3-HF) and 5-hydroxyflavone (5-HF) and quercetin (3,5,7,3 ,4 pentahydroxyflavone) have been obtained. The normal Raman (NR) spectra were taken in the powder form. The SERS spectra were obtained both on Ag colloids and Ag electrode substrates. Assignments of the spectrally observed normal modes were aided by density functional theory (DFT) calculations using the B3LYP functional and the 6-31+G * basis, a split valence polarized basis set with diffuse functions. Excellent fits were obtained for the observed spectra with little or no scaling. The most intense lines of the NR spectra are those in the C O stretching region (near 1600 cm −1 ). These lines are often weakened by proximity to the surface, while other lines at lower wavenumbers, due to in-plane ring stretches, tend to be strongly enhanced. The SERS spectrum of flavone is weak both on the colloid and on the electrode, indicating weak attachment to the surface. In contrast, the SERS spectra of the hydroxy derivatives of flavone are intense, indicating the assistance of OH groups in attachment to the surface. The spectra of the various species are compared, and a case study of application to detection of a textile dye (Persian berries), which contains quercetin, is presented.

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Section: -Hydroxyflavonementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Raman and surface‐enhanced Raman spectra of flavone and several hydroxy derivatives

Teslova

Corredor

Livingstone

et al. 2007

J Raman Spectroscopy

105

114

View full text Add to dashboard Cite

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“…BDE of 6OH is also almost unaffected by the torsion. Energy difference between the ground states of 3-hydroxyflavone and its tautomer is almost of 50 kJ mol -1 but ultrafast spectroscopy experiments confirmed that the first excited state of 3OH spontaneously forms excited state tautomer followed by the decay to the tautomer ground state (Dzugan et al, 1986). Significant difference in energy of HOMO, LUMO as well as their energy gap can be seen comparing the ground state of 3OH with t3OH (Fig.…”

Section: Resultsmentioning

confidence: 88%

Influence of catecholic ring torsion on hydroxyflavones

Michalík

Biela

Cagardová

et al. 2020

Acta Chimica Slovaca

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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.

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“…It is striking that the rate for the reverse proton transfer (GSRPT) of 3-HF was reported to be more than 6 orders of magnitude slower than the rate of the excited-state forward proton transfer. A controversial report of Aartsma and co-workers, 22 which contradicted the previous study 19 of Itoh et al, determined a lower limit of 3 × 10 10 s -1 for the rate of the reverse proton transfer by means of picosecond time-resolved absorption spectroscopy coupled with a stimulated emission pumping, SEP, technique. Another indication of fast reverse PT was a 60 fs lifetime for GSRPT found by Brucker and Kelly from the emission line-width for argon matrix isolated non-solvated 3-HF.…”

Section: Introductionmentioning

confidence: 96%

Time Resolved Surface Enhanced Raman Scattering Studies of 3-Hydroxyflavone on a Ag Electrode

et al. 2007

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Reverse proton transfer (RPT) of 3-hydroxyflavone (3-HF) from the tautomer ground state to normal ground state has been studied by time-resolved surface enhanced Raman scattering (TRSERS) in aqueous solution in the presence of oxygen. The tautomer ground state of 3-HF is formed by an exciting 337 nm nitrogen laser pulse and monitored by a 488 nm Ar + laser with gated photodiode array detection. B3LYP DFT calculations with 3-HF bound to the apex adatom of a Ag 20 cluster model show that a tilted orientation of the molecule with respect to the surface site is reasonable and is consistent with the SERS spectral characteristics. The geometry optimized structures also show that a cyclic monohyrate, 3-HF(H 2 O), species is stable from which biprotonic PT could take place. By studying the changes of some transient band intensities with time, the lifetime of tautomer 3-HF on a Ag electrode is determined to be 1.4 µs. Besides the photoinduced photooxygenation product, evidence for an additional endo-peroxide intermediate is obtained.

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On the ground-state tautomerization of 3-hydroxyflavone

Cited by 46 publications

References 12 publications

Raman and surface‐enhanced Raman spectra of flavone and several hydroxy derivatives

Raman and surface‐enhanced Raman spectra of flavone and several hydroxy derivatives

Influence of catecholic ring torsion on hydroxyflavones

Time Resolved Surface Enhanced Raman Scattering Studies of 3-Hydroxyflavone on a Ag Electrode

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