Lifetime of Singlet Oxygen and Quenching by NaN3 in Mixed Solvents

Singlet oxygen was generated by the photosensitization of erythrosine. The lifetime of singlet oxygen and the quenching rate constant for singlet oxygen by NaN3 were measured by a thermal lensing method in MeOH-H2O mixed solvents. The reciprocal of the lifetime increased linearly with the increase of the H2O mole fraction. Semi-log plot of the quenching constant against the reciprocal of the solvent polarity exhibited a linear relation. The quenching of the singlet oxygen by NaN3 may proceed through a partial charge-transfer intermediate. The activation energy for the quenching reaction of N3- + 1O2 →[N3·1O2-] increased with the increase of the solvent polarity. The lifetime was also measured in MeOH-ethyleneglycol mixed solvents, and its relation with viscosity was obtained

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Partial charge transfer contribution to the solvent isotope effect and photosensitized generation of singlet oxygen, O2(1Δg), by substituted ruthenium(ii) bipyridyl complexes in aqueous media

Photochemical & Photobiological Sciences ◽

10.1039/c4pp00117f ◽

2014 ◽

Vol 13 (9) ◽

pp. 1330-1337 ◽

Cited By ~ 10

Author(s):

Ayman A. Abdel-Shafi ◽

Hanaa A. Hassanin ◽

Shar S. Al-Shihry

Keyword(s):

Charge Transfer ◽

Singlet Oxygen ◽

Isotope Effect ◽

Aqueous Media ◽

Ruthenium Complexes ◽

Partial Charge ◽

Partial Charge Transfer ◽

Solvent Isotope Effect ◽

Solvent Isotope

Solvent isotope effect on the lifetime of the excited3MLCT states of ruthenium complexes,τD0/τH0, was found to depend on partial charge transfer to solvent as found from their dependence on theEoxof these complexes.

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Partial Charge Transfer at Iodide Adsorption from Aqueous Solution on Mercury Electrodes at Elevated Temperatures up to 453 K

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.1992.176.part_1.121 ◽

1992 ◽

Vol 176 (Part_1) ◽

pp. 121-126

Author(s):

U. Gaunitz ◽

W. Lorenz

Keyword(s):

Aqueous Solution ◽

Charge Transfer ◽

Elevated Temperatures ◽

Partial Charge ◽

Partial Charge Transfer ◽

Mercury Electrodes

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Спектральное исследование фотодинамических процессов в системе C-=SUB=-60-=/SUB=--(н-метилпирролидон)-кислород

Оптика и спектроскопия ◽

10.21883/os.2021.12.51736.2429-21 ◽

2021 ◽

Vol 129 (12) ◽

pp. 1493

Author(s):

И.М. Кисляков ◽

И.М. Белоусова ◽

В.М. Киселев ◽

И.В. Багров ◽

А.М. Стародубцев ◽

...

Keyword(s):

Quantum Yield ◽

Singlet Oxygen ◽

Transient Absorption ◽

Rapid Quenching ◽

Quenching Rate ◽

Broadband Absorption ◽

Laser Pumping ◽

Time Dependencies ◽

Quenching Rate Constant

The processes of photoexcitation and energy transfer in an air-saturated solution of fullerene C60 in n-methylpyrrolidone are studied. With femtosecond laser pumping at a wavelength л(p) = 520 nm, transient absorption spectra were obtained in the range 470-750 nm. Broadband absorption is observed at л > 650 nm as a result of aggregation of fullerene molecules, characterized by a short decay time of the picosecond scale. The analysis of the time dependencies indicates the presence of several processes. Within the proposed interpretation, we state a remarkable reduction in the time of singlet-triplet intersystem crossing with an increase of nanocluster size while the rapid quenching of the singlet state varies only slightly. The quantum yield of the triplet state can therefore increase, reaching 0.14. The phosphorescence spectra of singlet oxygen with a maximum at л = 1276 nm were measured with LED excitation at various wavelengths in the range 370-625 nm. The lifetime and quenching rate constant of singlet oxygen in n-methylpyrrolidone are determined. The combined quantum yield of triplet fullerene and singlet oxygen in n-methylpyrrolidone is estimated as 0.74. The efficiency spectra of the singlet oxygen photosensibilization in the C60-(n-methylpyrrolidone)-oxygen system are obtained, indicating the increasing role of large nanoclusters in this process during aging of the solution.

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