Proton and charge transfer reactions dynamics of a hydroxyflavone derivative in a polar solvent and in a cyclodextrin nanocavity

Sanz, Mikel; Organero, Juan Ángel; Douhal, Abderrazzak

doi:10.1016/j.chemphys.2007.04.013

Cited by 23 publications

(21 citation statements)

References 36 publications

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“…1c). [1][2][3]6 As discussed above in Section 3.1, our computational results are also in qualitative agreement with this assignment. Keeping in mind the existence of various un-solvated and solvated Cl-3HF species in polar solvents, we recorded fluorescence spectra using several different excitation wavelengths across the absorption window: 300 nm, 340 nm, 370 nm and 400 nm.…”

Section: Spectroscopy In Polar Solventssupporting

confidence: 89%

“…These putative structures offer valuable clues for elucidating the 3HF photophysics in solvents where inter-molecular H-bonding interferes with ESIPT. [1][2][3][4][5][6] Since the proton-transfer event is associated with a substantial realignment of electron density, the nature and position of substituents on the 3HF skeleton might significantly modulate the photophysics of 3HF derivatives. So far, the vast majority of the work on 3HF derivatives has focussed mainly on those with an electron-donating substituent at the 4 0 -position of the 2-phenyl ring, especially a dialkylamino substituent (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Here, intra-molecular charge transfer was found to interfere with the proton-transfer event. [6][7][8][9][10][11][12] Keeping these in mind, we undertook to probe the effect of a halogen atom as a substituent in the 4 0 -position of the 2-phenyl ring. Here we present our findings on 4 0 -chloro,3-hydroxyflavone (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Proton transfer reactions of 4′-chloro substituted 3-hydroxyflavone in solvents and aqueous micelle solutions

Ghosh

Pradhan

Mondal

et al. 2014

Phys. Chem. Chem. Phys.

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Flavonol 4'-chloro,3-hydroxyflavone (Cl-3HF) has been investigated in solvents of varying polarity and hydrogen-bonding capacity as well as in aqueous micelle solutions. Quantum chemical calculations indicate that although the Cl-atom at the 4'-position of the 2-phenyl ring weakly perturbs the electron distribution of the parent 3-hydroxyflavone, the nuclear framework remains largely intact, and excited state intra-molecular proton-transfer (ESIPT) is feasible. The ESIPT process in both polar solvents and micelles was found to be fast and irreversible, with remarkably long time-constants of several tens of picoseconds. This dramatic inhibition of the ESIPT rate (which is intrinsically a sub-picosecond event) could be rationalized in terms of the emergence of complexes between the solvent and the enol form of Cl-3HF, whose dynamics is coupled to the relatively slow dynamics of inter-molecular hydrogen bonds. In the micelle solutions, spectroscopic data establish that the guest Cl-3HF molecules localized almost exclusively at the polar exterior shell, where they experienced a nearly uniform local environment similar to that in moderately polar solvents. Thus, the Cl-3HF molecules tend to avoid the non-polar core of the micelles, in spite of being strongly hydrophobic themselves. This apparently unusual observation is explained by the formation of inter-molecularly hydrogen-bonded complexes between the guest Cl-3HF and the water molecules tethered to the polar shells of the micelles.

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Section: Spectroscopy In Polar Solventssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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Proton transfer reactions of 4′-chloro substituted 3-hydroxyflavone in solvents and aqueous micelle solutions

Ghosh

Pradhan

Mondal

et al. 2014

Phys. Chem. Chem. Phys.

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“…The former includes protic solvents like alcohols and water, where X = OR and OH respectively, while the latter includes nonprotic solvents like DMF and DMSO. In each of these cases, intermolecular H bonding is found to hinder ESIPT. − For the Type-III complex in particular, H-bonding basicity of the solvent may polarize the 3-OH group to the point of heterolysis, creating the 3HF anion and avoiding the ESIPT pathway altogether. − …”

Section: Introductionmentioning

confidence: 99%

Effect of an Electron-Donating Substituent at the 3′,4′-position of 3-Hydroxyflavone: Photophysics in Bulk Solvents

et al. 2016

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Introduction of the methylenedioxy substituent group in the 3',4'-position of 3-hydroxyflavone produced a significant impact on its proton-transfer response, much like the well-known 4'-N,N-dialkylamino group. The potential electron-donating property of the substituent helped sustain a high degree of charge separation in the excited enolic form of the molecule, which was stabilized in relatively polar solvents, whereupon the enol → tautomer excited state intramolecular proton-transfer (ESIPT) rate decreased. Hydrogen-bonding solvents caused further retardation by interfering with the intramolecular hydrogen bond that promotes ESIPT. Among these solvents, hydrogen bond donors appear to be more efficient ESIPT inhibitors than hydrogen bond acceptors. Femtosecond fluorescence experiments revealed that even among the latter the ESIPT time-constants become steadily longer as the hydrogen bond basicity of the solvent increases.

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“…The 3-hydroxy-2-phenylchromen-4-one derivatives exhibit the excited state intramolecular proton transfer (ESIPT) phenomenon [12,[16][17][18][19][20][21][22], based on the intramolecular proton transfer from a proton donor (-OH) to a proton acceptor (¼O) group. The proton transfer results in a zwitterion formation, possessing different spectral properties than the neutral form [12,[16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Photosensitization of titanium dioxide with 4′-dimethylaminoflavonol

Kondratyeva

Orzeł

Kobasa

et al. 2016

Materials Science in Semiconductor Processing

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Proton and charge transfer reactions dynamics of a hydroxyflavone derivative in a polar solvent and in a cyclodextrin nanocavity

Cited by 23 publications

References 36 publications

Proton transfer reactions of 4′-chloro substituted 3-hydroxyflavone in solvents and aqueous micelle solutions

Proton transfer reactions of 4′-chloro substituted 3-hydroxyflavone in solvents and aqueous micelle solutions

Effect of an Electron-Donating Substituent at the 3′,4′-position of 3-Hydroxyflavone: Photophysics in Bulk Solvents

Photosensitization of titanium dioxide with 4′-dimethylaminoflavonol

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