Photophysics and photochemistry of mercurochrome in reverse micelles

Altamirano, Marcela S.; Grassano, Micaela Estefania; Bertolotti, Sonia G.; Previtali, Carlos M.

doi:10.1016/j.jphotochem.2016.06.017

Cited by 4 publications

(2 citation statements)

References 43 publications

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“…At short times, after the laser pulse at 532 nm, the difference transient absorption spectrum of MCr in buffer pH 9 presents two maxima at 370 and 555 nm that can be ascribed to the T‐T transition. The spectrum is similar to those reported for other xanthene dyes . After the triplet decay, an absorption in the region 300–500‐nm remains which can be ascribed to the simultaneous absorption of the semireduced and semioxidized forms of the dye.…”

Section: Resultssupporting

confidence: 82%

“…The quenching may be explained by a static mechanism since the fluorescence lifetime (2 ns in water pH 8 ref. ) is not affected by the PAMAMs even at the highest concentration investigated (1 m m ), similarly to what was observed for Eos . The Stern–Volmer plots present a downward curvature, which can be ascribed to the residual emission of the dye bound to the dendrimer (Fig.…”

Section: Resultssupporting

confidence: 81%

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A Comparative Study on the Photophysical and Photochemical Properties of Dyes in the Presence of Low Generation Amino‐terminated Polyamidoamine Dendrimers

Grassano

Altamirano

Militello

et al. 2018

Photochem & Photobiology

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The photophysical and photochemical properties of the xanthene dyes mercurochrome (MCr) and eosin-Y (Eos); and the phenazine dye safranine-O (SF) are evaluated in the presence of amino-terminated polyamidoamine (PAMAM) dendrimers of low generations. The dendrimers produce a red shift in the UV-vis absorption spectra of the dyes, which increases with concentration and the size of the PAMAM molecule. The Stern-Volmer plots of fluorescence quenching for xanthenic dyes present a downward curvature. It is ascribed to a static mechanism involving a dye-dendrimer binding. A nonlinear fitting of the SV plots allows the calculation of the binding constants. For SF, the fluorescence is only slightly quenched by PAMAMs and the SV plots are linear. The binding constants are in the order K bind (SF) ( K bind (Eos) < K bind (MCr). The difference must be due to important specific structural effects. A decrease in the triplet lifetime and an increase in the absorption of the semireduced form of the dyes are observed in the presence of dendrimers. While for the two xanthene dyes, the rate constants reach the diffusional limit for G2 and G3, for SF they are one order of magnitude lower. This is explained by a different quenching mechanism of the two types of dyes.

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Section: Resultssupporting

confidence: 82%

Section: Resultssupporting

confidence: 81%

A Comparative Study on the Photophysical and Photochemical Properties of Dyes in the Presence of Low Generation Amino‐terminated Polyamidoamine Dendrimers

Grassano

Altamirano

Militello

et al. 2018

Photochem & Photobiology

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A Comparative Study on the Photophysics and Photochemistry of Xanthene Dyes in the Presence of Polyamidoamine (PAMAM) Dendrimers

2018

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The photophysical and photochemical properties of the xanthene dyes Eosin Y, Erythrosin B, and Rose Bengal are evaluated in the presence of amino-terminated polyamidoamine (PAMAM) dendrimers of relatively high generation (G3-G5) in alkaline aqueous solution. UV/Vis absorption and fluorescence spectra of the dyes show bathochromic shifts, which correlate with the size of the dendrimer. Binding constants (K ) are calculated from absorption data. The resulting high K values indicate strong interactions between both molecules. Triplet-triplet absorption spectra of the dyes are recorded by laser flash photolysis, and a decrease in the triplet lifetimes is observed in the presence of dendrimers. At the same time, an increase in the absorption of the semireduced form of the dyes is observed. Rate constants for triplet quenching ( k ) and radical quantum yields (Φ ) are obtained. The results are explained by a very efficient electron-transfer process from PAMAM to xanthene dyes for all of the dye/dendrimer couples that are evaluated.

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The effect of PAMAM dendrimers on the excited states of little-explored xanthene dyes. In search of eco-friendly photoinitiating systems

Militello

Porcal²,

Bertolotti³

et al. 2023

Journal of Photochemistry and Photobiology A: Chemistry

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Photophysics and photochemistry of mercurochrome in reverse micelles

Cited by 4 publications

References 43 publications

A Comparative Study on the Photophysical and Photochemical Properties of Dyes in the Presence of Low Generation Amino‐terminated Polyamidoamine Dendrimers

A Comparative Study on the Photophysical and Photochemical Properties of Dyes in the Presence of Low Generation Amino‐terminated Polyamidoamine Dendrimers

A Comparative Study on the Photophysics and Photochemistry of Xanthene Dyes in the Presence of Polyamidoamine (PAMAM) Dendrimers

The effect of PAMAM dendrimers on the excited states of little-explored xanthene dyes. In search of eco-friendly photoinitiating systems

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