The Quenching of Fluorescence. Deviations from the Stern-Volmer Law

Boaz, Harold E.; Rollefson, G. K.

doi:10.1021/ja01164a032

Cited by 251 publications

(118 citation statements)

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“…As previously mentioned the lowest energy transition in DAF is a 7~ -+ T * transition which is long-axis polarised. Since the trend observed in the absorption spectra on addition of protons is similar to that observed in other amines (16), it suggests that the nature of the lowest energy state in these ions remains the same. The mirror image relationship observed between the absorption and fluorescence spectra of the neutral and dication species clearly indicate that fluorescence in these species is taking place from the state polarised along the longer axis.…”

Section: Efsect Of Solventssupporting

confidence: 79%

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Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

Manoharan¹,

Dogra²

1987

Can. J. Chem.

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R. MANOHARAN and SNEH K. DOGRA. Can. J. Chem. 65, 2013Chem. 65, (1987. The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the -NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pK, values for the various prototropic reactions in So and SI states are determined and discussed.R. MANOHARAN et SNEH K. DOGRA. Can. J. Chem. 65, 2013Chem. 65, (1987. Lorsqu'on determine les spectres d'absorption du diamino-2,7 fluorkne (DAF) dans l'kther et dans l'acktonitrile, on observe un deplacement vers le rouge; ce resultat est dC1 soit a la capacite du solutC a donner des protons ou aux interactions dispersives du solvant. Par ailleurs, on observe un deplacement vers le bleu lorsque les spectres sont determines dans le mCthanol et dans l'eau; ces resultats sont dus a la nature du DAF qui a tendance a accepter des protons. Dans tous les solvants, le DAF agit comme donneur de proton dans 1'Ctat S, . Si on compare le spectre de fluorescence du monocation du DAF avec celui du DAF, on observe un dCplacement vers le rouge qui n'est pas dC1 au fait que le groupement -NH2 devient plus basique mais plutbt a la relaxation importante du solvant dans le milieu aqueux. Par ailleurs, le spectre de fluorescence du monocation du DAF dans le cyclohexane subit le dkplacement normal vers le bleu. On a determink et on discute des valeurs de pK, pour diverses reactions prototropiques dans les Ctats So et S,.[Traduit par la revue]During electronic transitions, the charge density changes at each atom of the molecule. Depending upon the nature of the transition as well as the nature of the molecule itself. the molecule may become less polar or more polar in the excited state as compared to the ground state. Due to this, the solvent molecules rearrange themselves in the S1 state, which is different from the ground state. Since the rearrangement of the solvent molecules involves bond breaking or bond formation, the time taken for this phenomenon can be compared with the period of vibrational motion and this is much smaller than the fluorescence lifetime. In other words, the fluorescence always occurs from the thermally equilibrated excited state even though the molecule, to begin with, is in the Franck-Condon state. The equilibrated state is of lower energy than the Franck-Condon state provided the polarity of the molecule changes (increases or decreases) and the solvent is polar (1, 2). Sometimes the stabilisation of the states, called solvent relaxation, is so large that either rev...

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Section: Efsect Of Solventssupporting

confidence: 79%

“…The pK*, calculated from fluorimetric titration curves is 13.9. This is in the same range as the observed pK:'s for other aromatic amines, indicating that the -NH2 group becomes strongly acidic on excitation (16).…”

Section: Efsect Of Solventssupporting

confidence: 74%

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

Manoharan¹,

Dogra²

1987

Can. J. Chem.

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“…[QliM) where V is the static quenching constant. The implication of V, however, depends on the model used, i. e., transient effect model [31], sphere of action [32] and dark complex model [33]. Since the CT complex formarion between an indole ring on lysozyme (or model compound) and pyridinium salts are observed at the ground state, k is conceivable to apply dark complex model in this system, in which an instantaneous quenching process by the excitation of the ground state encounter complex, (M* ---Q), which is generalized l:n complex, is assumed.…”

Section: Fluorescence ~Ectramentioning

confidence: 99%

Charge-transfer interaction of some pyridinium salts with hen egg-white lysozyme

Nakano

Komiyama

Iijima

1987

Colloid & Polymer Sci

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Abstract:The charge-transfer interaction of pyridinium salts with lysozyme and L-tryptophan has been investigated by visible absorption, circular dichroism and fluorescence spectroscopy. Four quaternized and substituted pyridinium salts were used as electron acceptors. L-tryptophan was used as a model compound of electron donor for the purpose of the comparison with lysozyme. The binding constants obtained from absorption and circular dichroism spectra were 2.0-13 M -1 and the sequence of the magnitude was found as EPCl(1-ethylpyridinium chloride) < MPCl(1-methylpyridinium chloride) < MNCl(1-methylnicotinamide chloride) < MNMCl(1-methyl-3-carbomethoxypyridinium chloride), which could be explained by the electron affinity of the pyridinium salt. The fluorescence spectra of lysozyme and L-tryptophan in the absence and presence of pyridinium salts were interpreted by Stern-Volmer plot. The static constants thus determined were in agreement with the binding constants obtained by other methods.

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“…Both positive and negative curvatures have been observed [51]. Downward curvatures in S-V plots of luminescence intensity and lifetime measurements for systems involving multiple and oppositely charged reactants have been attributed to decrease in the reactant activities as a result of increasing ionic strength.…”

Section: Non-linear S-v Behaviormentioning

confidence: 97%

Luminescence behavior of tetraaza macrocylic nickel (II) complexes and non-linear Stern–Volmer quenching

Balasubramanian

2004

Journal of Luminescence

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The Quenching of Fluorescence. Deviations from the Stern-Volmer Law

Cited by 251 publications

References 0 publications

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

Charge-transfer interaction of some pyridinium salts with hen egg-white lysozyme

Luminescence behavior of tetraaza macrocylic nickel (II) complexes and non-linear Stern–Volmer quenching

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