Lowest excited singlet state of hydrogen-bonded methyl salicylate

HEIMBROOK, L. A.; Kenny, Jonathan E.; Kohler, Bryan E.; Scott, Gary W.

doi:10.1021/j100225a022

Cited by 121 publications

(108 citation statements)

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“…1A) [11][12][13]. Rotamer A is more thermodynamically stable than B (enthalpy difference is 14 and 10 kJ/mol in case of SA and methyl salicylate (MS) [14,15]) due to an intramolecular hydrogen bond. Excitation of rotamer A in the gas phase and in non-polar solvents gives rise to an ultrafast (∼60 fs in case of MS [13]) excited state intramolecular proton transfer (ESIPT) from the hydroxyl to the carboxyl group resulting to the formation of a tautomeric form of the acid (Fig.…”

Section: Introductionmentioning

confidence: 99%

Photolysis of sulfosalicylic acid in aqueous solutions over a wide pH range

Pozdnyakov

Plyusnin

Grivin

et al. 2006

Journal of Photochemistry and Photobiology A: Chemistry

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Nanosecond laser flash photolysis, absorption and fluorescent spectroscopy were used to study the influence of pH on the photophysical and photochemical processes of 5-sulfosalicylic acid (SSA) in aqueous solutions. Information on the excited singlet state intramolecular proton transfer (ESIPT) of the SSA ions could be deduced from the dependence of the quantum yield and the spectral maximum of SSA fluorescence on the pH of the medium. The main photochemical active form of SSA at pH < 10 is the dianion (HSSA 2− ). Excitation of this species gives rise to the HSSA 2− triplet state, to the SSA •2− radical anion and to the hydrated electron. In a neutral medium, the main decay channels of these intermediates are T-T annihilation, recombination and capture by the HSSA 2− dianion, respectively. A decrease of pH leads to an increase of the second-order rate constants of disappearance of both HSSA 2− triplet state and SSA •2− radical anion due to their protonation.

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Section: Introductionmentioning

confidence: 99%

Photolysis of sulfosalicylic acid in aqueous solutions over a wide pH range

Pozdnyakov

Plyusnin

Grivin

et al. 2006

Journal of Photochemistry and Photobiology A: Chemistry

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“…1a). Rotamer A is thermodynamically more stable than B (enthalpy difference of 14 and 10 kJ Á mol À1 for SA and methyl salicylate (MS) [5,15] ) due to a strong intramolecular hydrogen bond between the carboxyl and hydroxyl groups.…”

Section: Introductionmentioning

confidence: 99%

“…[14] The fluorescence properties of SA and SADs have been studied in the gas phase and in series of polar (water, ethanol, dimethylformamide, chloroform) and nonpolar solvents (benzene, n-heptane, isooctane, methylcyclohexane). [1][2][3][4][5][6][7][8][9][10][11][12][13] In the gas phase and in nonpolar solvents, the ground state of SA and SADs exists in two rotameric forms, A and B (Fig. 1a).…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] On the other hand, SADs are considered as representatives of the complexing functional groups in humic substances and can serve as model compounds for investigating the photochemical properties of natural humic and fulvic acids. [14] The fluorescence properties of SA and SADs have been studied in the gas phase and in series of polar (water, ethanol, dimethylformamide, chloroform) and nonpolar solvents (benzene, n-heptane, isooctane, methylcyclohexane).…”

Section: Introductionmentioning

confidence: 99%

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The photophysics of salicylic acid derivatives in aqueous solution

Pozdnyakov

Pigliucci

Tkachenko

et al. 2008

J of Physical Organic Chem

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The photophysics of a number salicylic acid derivatives (SADs) in aqueous solutions was investigated in a wide range of pH by time-correlated single photon counting (l ex ¼ 350 nm, t resp ¼ 300 ps) and fluorescence up-conversion (l ex ¼ 266 nm, t resp ¼ 300 fs) techniques. The acid-base equilibrium constants in the ground (pK a ) and the excited states (pK Ã a ), the fluorescence quantum yields as well as the lifetimes of anionic, neutral, and cationic forms of SADs were determined. Evidence of ultrafast excited-state intramolecular proton transfer (ESIPT) leading to the formation of the proton-transferred excited state of SADs was obtained from the fluorescence up-conversion measurement. The nature of the ESIPT process is discussed.

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“…1 represent a unique observation of proton-transfer spectroscopy at moderate resolution in a 77 K crystal system. The only previous examples of resolved proton-transfer spectra were for methyl salicylate proton transfer in a neon matrix (15) at 4.2 K and those for methyl salicylate in a free-jet spectrum (16).…”

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confidence: 99%

Proton-transfer spectroscopy of 3-hydroxyflavone in an isolated-site crystal matrix.

McMorrow¹,

Kasha²

1984

Proc. Natl. Acad. Sci. U.S.A.

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The isolated-site low-temperature crystal matrix (dilute solutions in heptane and in octane) (Shpol'skii matrix) is shown to be operative for the spectroscopic study of 3-hydroxyflavone luminescence. The observed luminescence is demonstrated to be unique proton-transfer fluorescence from the excited tautomer. A separate study at higher concentrations of aggregated molecule luminescence and excitation spectra distinguishes these for 3-hydroxyflavone from isolatedmolecule spectra. The application of the Shpol'skii matrix lowtemperature spectroscopy technique is suggested for other large heteroaromatic molecules, such as biomolecules containing polar groups that impart low solubility in nonaqueous solvents.The yellow-green fluorescence of quercetin is the standard criterion for recognition of this polyhydroxyflavone on a thin-layer chromatography plate (1). The observation of a fluorescence in the middle of the visible region posed a major anomaly because the UV absorption of the flavonols should result in UV or at most a deep-violet fluorescence. Sengupta and Kasha (2) showed that the yellow-green fluorescence of quercetin and of its simpler homolog, 3-hydroxyflavone, arise from an excited proton-transfer tautomer of the normal molecule.

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Lowest excited singlet state of hydrogen-bonded methyl salicylate

Cited by 121 publications

References 0 publications

Photolysis of sulfosalicylic acid in aqueous solutions over a wide pH range

Photolysis of sulfosalicylic acid in aqueous solutions over a wide pH range

The photophysics of salicylic acid derivatives in aqueous solution

Proton-transfer spectroscopy of 3-hydroxyflavone in an isolated-site crystal matrix.

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