PHOTOCHEMICAL REACTION OF 6<i>H</i>-BENZO[<i>cd</i>]PYREN-6-ONE (NAPHTHANTHRONE)

Ohshima, Shigeru; Ohtsuki, Tsuyuka; Kimura, Eri; Yamaguchi, M.; Toyoshima, Takuya; Takekawa, Minoru

doi:10.1080/10406630802435027

Cited by 5 publications

(9 citation statements)

References 7 publications

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“…Accordingly the solvent-deuteration effect for the fluorescence enhancement differs from the usual hydrogen abstraction where deuteration of the alkyl group dominates. The difference in the deuteration effect reinforces our assumption that the fluorescence enhancement arises from association of NT with the solvent, not from hydrogen abstraction of NT from the solvent, though their initial steps resemble each other (4). Furthermore the experimental findings indicate that there are two kinds of association complexes; an NT molecule interacts strongly with solvent's hydroxyl group in one complex (referred to as complex I) and with solvent's alkyl group in the other complex (referred to as complex II).…”

Section: Interpretation Of the Isotope Effectssupporting

confidence: 75%

“…The triplet state of NT, NT*, produced by irradiation, interacts with the nearest solvent molecule constituting the cage to form an associative complex. Since the association occurs between the oxygen atom of NT's carbonyl group and a hydrogen atom of the alcohol, as described above, the nπ*-character of NT is substantially weakened in the complex; semi-empirical molecular orbital calculations predict that the associative complex is strongly fluorescent (4). In addition the complex becomes held more rigidly to the cage through the associated solvent molecule.…”

Section: Downloaded By [Korea University] At 06:26 26 December 2014mentioning

confidence: 95%

“…The studies report that the fluorescence of NT is weak because of its nπ* character and the intensity of the fluorescence is almost equal to that of phosphorescence at the liquid nitrogen temperature (2,3). On strong irradiation of an NT solution before spectral measurements, however, the fluorescence increases by several ten times, accompanied by a blue shift (4). This fluorescence enhancement also occurs at the liquid nitrogen temperature; on the contrary, the phosphorescence decreases slightly on such irradiation.…”

Section: Introductionmentioning

confidence: 93%

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FLUORESCENCE ENHANCEMENT OF 6H-BENZO[cd]PYREN-6-ONE (NAPHTHANTHRONE): EFFECTS OF CONCENTRATION, LIGHT INTENSITY, AND DEUTERATION OF SOLVENTS

Yagishita

Ohshima

2010

GPOL

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Fluorescence of naphthanthrone, 6H-benzo[cd]pyren-6-one, in degassed organic solution increases by a factor of 10-100 on strong irradiation and the spectrum is blueshifted. To clarify the mechanism of the fluorescence enhancement, we investigated effects of intensity of irradiation, deuteration of solvents, and concentration of naphthanthrone on the enhancement. The fluorescence was more rapidly enhanced with stronger irradiation, though there was a latent period of several minutes. The enhancement was, however, reduced to 30-70% by deuteration of the solvents. The spectra of enhanced fluorescence showed more defined vibrational structure and larger blue-shift as the concentration was decreased from 10 −4 to 10 −6 M. These experimental results were interpreted on the basis of the associative complex model: the association of naphthanthrone with a solvent molecule proceeds step-wisely in a solvent cage by several times of excitation and undergoes kinetic isotope effects. At lower concentrations, the movement of the associative complex is more strongly suppressed, leading to enhanced fluorescence spectra with clearer vibrational structure and larger blue-shift.

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Section: Interpretation Of the Isotope Effectssupporting

confidence: 75%

Section: Downloaded By [Korea University] At 06:26 26 December 2014mentioning

confidence: 95%

Section: Introductionmentioning

confidence: 93%

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FLUORESCENCE ENHANCEMENT OF 6H-BENZO[cd]PYREN-6-ONE (NAPHTHANTHRONE): EFFECTS OF CONCENTRATION, LIGHT INTENSITY, AND DEUTERATION OF SOLVENTS

Yagishita

Ohshima

2010

GPOL

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“…So far, the study on the fluorescence enhancement has been mainly spectroscopic, indicating that the enhancement arises from association of a solute molecule with a solvent (1,2). In the present study, we also aimed to confirm the validity of the association model of the enhancement and tried to detect such an association complex: we applied high performance liquid chromatography to an ethanol solution of NT that had exhibited the fluorescence enhancement and analyzed chromatograms obtained.…”

Section: Introductionmentioning

confidence: 90%

“…Naphthanthorone (abbreviated as NT), 6H-benzo[cd]pyren-6-one, exhibits a peculiar phenomenon in fluorescence: when its degassed solution is strongly irradiated in advance, the fluorescence is significantly enhanced by about 100 times (1,2). Such fluorescence enhancement, however, has never been reported except in NT.…”

Section: Introductionmentioning

confidence: 97%

Fluorescence Enhancement of Polycyclic Aromatic Ketones

Yagishita¹,

Ohshima²

2012

Polycyclic Aromatic Compounds

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The fluorescence enhancement, which has been reported only for naphthanthrone, was also observed in benzanthrone, 3-nitrobenzanthrone, and 2-nitronaphthanthrone in degassed solution irradiated with strong light. These molecules exhibiting the enhancement were non fluorescent, or rather phosphorescent. Therefore, it was confirmed that the fluorescence enhancement is a general phenomenon occurring in phosphorescent molecules and that the enhancement arises from a reaction via their triplet state. The finding that 3-nitrobenzanthrone, known as a potent mutagen, showed significant fluorescence enhancement, suggests a practical application of the enhancement to fluorescence spectroscopic analysis for mutagenic nitrated aromatic compounds that hardly fluoresce. On the association model the fluorescence enhancement is caused by an association complex, which has never been identified experimentally. The existence of the complex was proved by the HPLC chromatography for an ethanol solution of naphthanthrone which had exhibited fluorescence enhancement.

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