Excited-state dynamics of 3-hydroxyflavone

Strandjord, Andrew; Courtney, S. H.; Friedrich, Donald M.; Barbara, Paul F.

doi:10.1021/j100230a008

Cited by 124 publications

(69 citation statements)

References 4 publications

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“…This observation confirms our general thesis (4) that the intrinsic property of the internally H-bonded 3-hydroxyflavone is to undergo proton transfer to the benzopyrillium tautomer (structure I Right) under photoexcitation. In the recent laser kinetic studies of 3-hydroxyflavone luminescences, it was assumed that the intrinsic property of this molecule is to exhibit normal fluorescence at low temperatures (6)(7)(8)(9). The present results and our previous studies (3,4) indicate that, at least at 77 K, the intrinsic excited-state behavior of 3-hydroxyflavone after So -* S1 excitation is to undergo S1 --S' proton transfer, followed by Si SO proton transfer fluorescence (Fig.…”

supporting

confidence: 68%

“…The effects of aggregation in low-temperature hydrocarbon solutions of 3-hydroxyflavone have not been reported previously because the effects of solvation in the contaminated solutions used (2,(6)(7)(8) completely dominated the luminescence properties. The broad, diffuse, and red-shifted nature (Fig.…”

Section: Aggregation Spectroscopy Of 3-hydroxyflavone In Hydrocarbon mentioning

confidence: 89%

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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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supporting

confidence: 68%

Section: Aggregation Spectroscopy Of 3-hydroxyflavone In Hydrocarbon mentioning

confidence: 89%

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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“…Since the original work of Forster (2) and Weller (3) on 1-naphthylamine-4-sulfonate, considerable research work on proton transfer has been done over the years (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Due to these efforts, the acid-base behavior of various substituent groups attached to aromatic moieties in both the So and S , electronic states is now well understood.…”

Section: Introductionmentioning

confidence: 99%

Proton transfer equilibrium reactions in some substituted 3H-indole probe molecules: role played by the TICT state

Sarpal¹,

Belletête²,

Durocher³

1993

Can. J. Chem.

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(6). The dependence of absorption and fluorescence spectral characteristics upon acidity has allowed us to characterize four species, namely, the anion (A), the neutral molecule (N), the cation (C), and the dication (DC), for molecules 2 and 3 . Molecules 4, 5, and 6 give rise to an additional anion due to the hydrolysis of the ester group. The relative order of protonations to available sites is discussed. The ring-protonated species have shown the Ph, and indole rings to be coplanar in both the ground and first excited singlet states. A low-energy non-emissive twisted intramolecular charge transfer (TICT) state taking its origin in the dimethylamino moiety is suggested from INDO-S calculations to explain the strong fluorescence quenching of these ring-protonated species. Acidity constants for the various prototropic equilibria have been determined experimentally both in the ground and in the excited singlet states. Forster cycle calculations have been used to supplement the various equilibrium constants. Possible applications in organized assemblies are discussed. additionnel qui provient d'une hydrolyse de l'ester. On discute de I'ordre relatif des protonations des divers sites. On a dCmontrC que les espbces protonCes des cycles benzenique et indolique sont coplanaires tant dans 1'Ctat fondamental que dans le premier Ctat excitC. Sur la base de calculs INDO-S, on suggbre qu'un Ctat de transfert de charge intramolCculaire dCformC, de basse Cnergie, non radiatif et dont I'origine se trouverait dans la portion dimCthylamino peut expliquer la forte dksactivation de fluorescence de ces espbces protonkes sur le cycle. On a dCterminC experimentalement les constantes d'aciditt des divers Cquilibres prototropiques tant dans 1'Ctat fondamental que dans les Ctats excites. On a utilisC des calculs de cycles de Forster comme supplCments aux diverses constantes d'kquilibre. On discute de diverses applications possibles pour des systbmes organises.[Traduit par la rCdaction]

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“…The huge potential in the ESIPT process has provoked massive interest among the photophysicists and photochemists. Studies range from the choice of a variety of homo-and heterocyclic aromatic molecular systems to a wide variety of pure and mixed homogeneous and microheterogeneous solvents [1][2][3][4][5][6][7][8][9][10][11]. This phenomenon has widespread implications in photostabilizers [12], laser dyes [13] and also in the biological fields [14].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Modelling for the Ground State Rotamerisation and Excited State Intramolecular Proton Transfer of 2-(2’-hydroxyphenyl)oxazole, 2-(2’-hydroxyphenyl)imidazole, 2-(2’-hydroxyphenyl)thiazole and Their Benzo Analogues

Purkayastha

Chattopadhyay

2003

IJMS

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Two series of compounds, one comprising of 2-(2′-hydroxyphenyl)benzoxazole (HBO), 2-(2′-hydroxyphenyl)benzimidazole (HBI), 2-(2′-hydroxyphenyl)benzothiazole (HBT), and the other of 2-(2′-hydroxyphenyl)oxazole (HPO), 2-(2′-hydroxyphenyl)imidazole (HPI) and 2-(2′-hydroxyphenyl)thiazole (HPT) are susceptible to ground state rotamerization as well as excited state intramolecular proton transfer (ESIPT) reactions. Some of these compounds show experimental evidence of the existence of two ground state conformers. Out of these two one undergoes ESIPT reaction leading to the formation of the tautomer. The two photophysical processes, in combination, result in the production of a number of fluorescence bands each one of which corresponding to a particular species. Semiempirical AM1-SCI calculations have been performed to rationalize the photophysical behaviour of the compounds. The calculations suggest that for the first series of compounds, two rotational isomers are present in the ground state of HBO and HBI while HBT has a single conformer under similar circumstances. For the molecules of the other series existence of rotamers depends very much on the polarity of the environment. The potential energy curves (PEC) for the ESIPT process in different electronic states of the molecules have been generated theoretically. The simulated PECs reveal that for all these systems the IPT reaction is unfavourable in the ground state but feasible, both kinetically and thermodynamically, in the S 1 as well as T 1 states.

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Excited-state dynamics of 3-hydroxyflavone

Cited by 124 publications

References 4 publications

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

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

Proton transfer equilibrium reactions in some substituted 3H-indole probe molecules: role played by the TICT state

Theoretical Modelling for the Ground State Rotamerisation and Excited State Intramolecular Proton Transfer of 2-(2’-hydroxyphenyl)oxazole, 2-(2’-hydroxyphenyl)imidazole, 2-(2’-hydroxyphenyl)thiazole and Their Benzo Analogues

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