Fluorescence quenching of Safranine T by inorganic anions in Tween micelles

The fluorescence quenching of the dye Safranine T by various inorganic anions such as [Fe(CN6)]3, [Fe(CN6)]4, I, Br, NO2, and N3 in aqueous solution and in nonionic micellar solutions of Tweens (Tween 20, Tween 40, and Tween 80) was studied. The SternVolmer quenching constants and quenching rate constants were evaluated. Compared to the quenching efficiency in aqueous media, that of the micellar media was found to be lower, except when iodide ion was used as a quencher. With the exception of the iodide ion, it has been established that collisional quenching plays a major role in the photophysical process. In the case of the iodide ion, both static and collisional quenching processes play a major role, owing to the complexation of iodide ion with Tween micelles. The SternVolmer quenching constants were found to be dependent on the ionic strength of the medium.Key words: fluorescence, static quenching, Tweens, SternVolmer constant, micellar media.

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The surfactant concentration-dependent behaviour of safranine T in Tween (20, 40, 60, 80) and Triton X-100 micellar media

Journal of Photochemistry and Photobiology A Chemistry ◽

10.1016/s1010-6030(97)00110-x ◽

1997 ◽

Vol 109 (1) ◽

pp. 29-34 ◽

Cited By ~ 27

Author(s):

Kamala Rani Acharya ◽

Subhash C. Bhattacharya ◽

Satya P. Moulik

Keyword(s):

Surfactant Concentration ◽

Tween 20 ◽

Micellar Media ◽

Safranine T ◽

Triton X ◽

Dependent Behaviour

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Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides

International Journal of Molecular Sciences ◽

10.3390/ijms22020885 ◽

2021 ◽

Vol 22 (2) ◽

pp. 885

Author(s):

Krzysztof Żamojć ◽

Irena Bylińska ◽

Wiesław Wiczk ◽

Lech Chmurzyński

Keyword(s):

Fluorescence Quenching ◽

Rate Constants ◽

Quenching Rate ◽

Time Resolved ◽

Radiative Processes ◽

Diffusion Limited ◽

Fluoroquinolone Antibiotics ◽

Quenching Efficiency ◽

Bimolecular Quenching ◽

The Impact

The influence of the stable 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) nitroxide and its six C4-substituted derivatives, as well as two C3-substituted analogues of 2,2,5,5-tetramethylpyrrolidynyl-N-oxyl (PROXYL) nitroxide on the chosen fluoroquinolone antibiotics (marbofloxacin, ciprofloxacin, danofloxacin, norfloxacin, enrofloxacin, levofloxacin and ofloxacin), has been examined in aqueous solutions by UV absorption as well as steady-state and time-resolved fluorescence spectroscopies. The mechanism of fluorescence quenching has been specified and proved to be purely dynamic (collisional) for all the studied systems, which was additionally confirmed by temperature dependence experiments. Moreover, the selected quenching parameters—that is, Stern–Volmer quenching constants and bimolecular quenching rate constants—have been determined and explained. The possibility of electron transfer was ruled out, and the quenching was found to be diffusion-limited, being a result of the increase in non-radiative processes. Furthermore, as the chosen nitroxides affected the fluorescence of fluoroquinolone antibiotics in different ways, an influence of the structure and the type of substituents in the molecules of both fluoroquinolones and stable radicals on the quenching efficiency has been determined and discussed. Finally, the impact of the solvent’s polarity on the values of bimolecular quenching rate constants has been explained. The significance of the project comes from many applications of nitroxides in chemistry, biology and industry.

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Formation of CT complexes and electron transfer from excited molecules of anthracene derivatives to methylviologen in aqueous and micellar media

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19871658 ◽

1987 ◽

Vol 52 (7) ◽

pp. 1658-1665

Author(s):

Viktor Řehák ◽

Jana Boledovičová

Keyword(s):

Electron Transfer ◽

Complex Formation ◽

Fluorescence Quenching ◽

Rate Constant ◽

Formation Constants ◽

Dynamic Quenching ◽

Micellar Media ◽

Complex Formation Constants ◽

Anthracene Derivatives ◽

Ct Complexes

Disodium 1,5- and 1,8-anthracenedisulphonate (ADS) and 9-acetylanthracene form coloured CT complexes with methylviologen (MV2+) in aqueous and micellar media. The complex formation constants and molar absorptivities were determined by the Benesi-Hildebrandt method. In the fluorescence quenching, its static component plays the major role. The dynamic quenching component is determined by the rate constant of electron transfer from the S1 state of ADS to MV2+.

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Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20021154 ◽

2002 ◽

Vol 67 (8) ◽

pp. 1154-1164 ◽

Cited By ~ 2

Author(s):

Nachiappan Radha ◽

Meenakshisundaram Swaminathan

Keyword(s):

Charge Transfer ◽

Fluorescence Quenching ◽

Ground State ◽

Rate Constants ◽

Quenching Mechanism ◽

Quenching Rate ◽

Charge Transfer Interaction ◽

Electronically Excited ◽

A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

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