Studies on Photochemical Processes of Xanthene Dyes by Means of the Transient Absorption Spectra in the Visible/Near-IR Regions

Islam, Shafiqul D.-M.; Yoshikawa, Yuko; Fujitsuka, Mamoru; Watanabe, Akira; Ito, Osamu

doi:10.1246/bcsj.71.1543

Cited by 23 publications

(10 citation statements)

References 43 publications

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“…The T–T transient absorption of Eos in MeCN presents two main positive bands at 400 and 580 nm and a strong bleaching at 520 nm (not shown). The triplet decays with a lifetime of the order of 100 μs mainly by self‐quenching and is efficiently quenched by electron donors and acceptors . In the presence of benzoquinones, it decays with first‐order kinetics.…”

Section: Resultsmentioning

confidence: 99%

Comparison of the Kinetics of Electron Transfer in the Diffusion Limit for the Singlet and Triplet Quenching of Eosin Y by Quinones

Bertolotti

Montejano

Previtali

2013

Photochem & Photobiology

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Electron transfer (ET) rate constants were determined by means of lifetime measurements for the fluorescence quenching and by laser flash photolysis for the triplet quenching of the dye eosin Y by benzoquinones in acetonitrile. The results represent a new aspect of the dependence of the rate constants with the driving force in the diffusion limit region. That is, the rate constants for singlet quenching in the highly negative region of ΔGet do not decrease as predicted by Marcus theory, but rather show a small positive dependence on the driving force. However, it is found that, in the same free energy range, the triplet rate constants are lower than those for the singlet process. They also increase with the exergonicity of the reaction, but the dependence with ΔGet is less marked than that found for the singlet reaction. Even at a Gibbs energy change of -1.0 eV the triplet quenching rate constants do not reach the theoretical diffusion limit. The results are analyzed using the current theories for diffusion-mediated ET reactions.

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Section: Resultsmentioning

confidence: 99%

Comparison of the Kinetics of Electron Transfer in the Diffusion Limit for the Singlet and Triplet Quenching of Eosin Y by Quinones

Bertolotti

Montejano

Previtali

2013

Photochem & Photobiology

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“…[35,36] In this study, two phenols were chosen: 4-aminophenol (4AP) which quenches very efficiently the triplet excited state of RB ( 3 k q = 4.9 6 10 9 m -1 N s -1 in CH 3 CN) and 3-methoxyphenol (3MP) for which the H-donating ability towards 3 RB * is several order of magnitude lower ( 3 k q = 9 6 10 5 m -1 N s -1 in CH 3 CN). The quenching of the singlet excited state of RB by 4AP and 3MP occurred with rate constants of 2 6 10 10 m -1 N s -1 and 4.5 6 10 9 m -1 N s -1 respectively.…”

Section: The Role Of the Reduced Dye Radical (Dh9)mentioning

confidence: 99%

Photopolymerization Reactions Initiated by a Visible Light Photoinitiating System: Dye/Amine/Bis(trichloromethyl)-Substituted-1,3,5-Triazine

Grotzinger

Burget

Jacques

2001

Macromol. Chem. Phys.

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Addition of a bis(trichloromethyl)‐substituted‐1,3,5‐triazine (Tz) to a dye/amine photoinitiating system leads clearly to an increased efficiency of polymerization under visible light irradiation. The polymerization rates obtained with three triazine derivatives with either phenosafranine, eosin or Rose Bengal as light absorbing species, were measured. Whatever the investigated dye/amine mixture, the addition of Tz led to a strong synergistic effect: the inhibition time decreased and the polymerization rate increased significantly when the three components were used jointly. The spectroscopic and redox properties of the Tz were measured. The system dye/amine/Tz was investigated through time‐resolved laser spectroscopy and steady state fluorescence experiments. A detailed reaction mechanism was elaborated which shows that Tz acts mainly as an inhibitor scavenger. The involved inhibitor is the reduced dye (DH∗︁) arising from the first photochemical reaction between the excited states of the dye and the amine.

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“…In non-hydrogen-bond donating solvents, solvation of dye molecules probably occurs via dipole-dipole interactions, whereas in hydrogen-bond donating solvents the phenomenon is more hydrogen bonding in nature [28,29]. Studies in xanthenes dyes such as eosin and erythrosin showed that the maximum absorption peak in aqueous solutions shifts to higher wavelengths in ethanol, and the same type of solvent dependency of the absorption spectra was observed for hidroxyxanthenes, in which the shift in the absorption maximum is due to hydrogen bonding [30].…”

Section: Interactions Between Photopolymer Components and Zeolite Nanmentioning

confidence: 97%

Photopolymerizable nanocomposites for holographic recording and sensor application

Leite¹,

Naydenova²,

Mintova

et al. 2010

Appl. Opt.

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Novel nanocomposites consisting of a water soluble acrylamide-based photopolymer and colloidal zeolite nanoparticles of zeolite Beta and zeolite A were prepared. The interactions between the photopolymer components and zeolite nanoparticles in the photopolymerizable nanocomposites were characterized for the first time by 13 C NMR and Visible spectroscopy. It was found that the zeolite Beta nanoparticles (up to 5% wt.) behave as a non-inert additive, resulting in an effective increase in layer thickness that causes doubling of the diffraction efficiency of the nanocomposite in comparison to that of the undoped photopolymer. On the other hand, the nanocomposite containing zeolite A nanoparticles showed no evidence of interaction with the polymer matrix and had similar values of diffraction efficiency and for small addition of nanoparticles (up to 2.5% wt.) showed slightly higher light induced refractive index modulation of the grating when compared to the undoped photopolymer. The good optical compatibility between the zeolites nanoparticles and the polymer allows a versatile design of photopolymerizable nanocomposites with different properties by selecting the adequate type of zeolite. The nanocomposite containing zeolite Beta nanoparticles demonstrates selective sensing behavior towards toluene and can be coated in either glass or plastic substrates and exposed directly to the environmental conditions.

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Studies on Photochemical Processes of Xanthene Dyes by Means of the Transient Absorption Spectra in the Visible/Near-IR Regions

Cited by 23 publications

References 43 publications

Comparison of the Kinetics of Electron Transfer in the Diffusion Limit for the Singlet and Triplet Quenching of Eosin Y by Quinones

Comparison of the Kinetics of Electron Transfer in the Diffusion Limit for the Singlet and Triplet Quenching of Eosin Y by Quinones

Photopolymerization Reactions Initiated by a Visible Light Photoinitiating System: Dye/Amine/Bis(trichloromethyl)-Substituted-1,3,5-Triazine

Photopolymerizable nanocomposites for holographic recording and sensor application

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