Bergwinkl, Sebastian and Allacher, Carina and Heilmeier, Karina and Kutta, Roger Jan and Dick, Bernhard and Nuernberger, Patrick (2025) Ultrafast Studies of Different Oxidation and Protonation States of Rhodamine 6G and Implications for Photocatalysis. CHEMPHOTOCHEM, 9 (11). ISSN 2367-0932
Full text not available from this repository. (Request a copy)Abstract
The long-lived radical R6G center dot, derived from the cationic dye rhodamine 6G (R6G+) by reduction, is of growing interest in photoredox catalysis. This manuscript discusses three methods of its preparation in dimethylsulfoxide, highlighting spectral differences due to solvatochromism, co-solutes, and the basicity of the solution. Upon excitation, R6G center dot* can release an electron to a substrate molecule or as a solvated electron, leading back to R6G+. However, a second reduction of R6G center dot is not observed to be reversible here, decreasing the overall concentration of R6G center dot and R6G+ with time. R6G+ can also be deprotonated to R6G1 under basic conditions, and even double deprotonation to R6G2- is possible, though this may undergo irreversible reaction over time. Excitation of R6G1 leads to the formation of a photoproduct stable for seconds, which then reforms R6G1. If R6G center dot is exposed to basic conditions in the presence of oxygen, it is oxidized to R6G+, which is then quickly deprotonated to yield R6G1 again. Hence, in basic solution, R6G1 is the predominant species, so that other light-induced reaction pathways than with R6G+ are accessible. It remains to be determined whether the photoproduct of R6G1 could be beneficial for a photocatalytic application under strongly basic conditions.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOTOINDUCED ELECTRON-TRANSFER; TRANSIENT ABSORPTION-SPECTROSCOPY; GENERATING HYDRATED ELECTRONS; SOLVATED ELECTRONS; PHOTOPHYSICAL PROPERTIES; FLUORESCENCE LIFETIMES; PHOTOREDOX CATALYSIS; ONE-PHOTON; ISOMERIZATION; MECHANISM; electron transfer; photocatalysis; photoredox processes; reaction mechanisms; ultrafast spectroscopy |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Physical Chemistry I > Prof. Dr. Patrick Nürnberger Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Bernhard Dick |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 07 May 2026 05:06 |
| Last Modified: | 07 May 2026 05:06 |
| URI: | https://pred.uni-regensburg.de/id/eprint/66238 |
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