PHOTOELECTROCHEMICAL ELECTRON-SPIN RESONANCE .3. THE REDUCTION OF FLUORESCEIN - A PHOTO-DISP2 REACTION
The reduction of the dye fluorescein in an aqueous solution of high pH (13), at mercury-plated electrodes, has been investigated using in situ electrochemical e.s.r. and a channel electrode flow cell. In the dark, a simple reversible one-electron reduction is observed leading to the formation of the...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
1988
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| Summary: | The reduction of the dye fluorescein in an aqueous solution of high pH (13), at mercury-plated electrodes, has been investigated using in situ electrochemical e.s.r. and a channel electrode flow cell. In the dark, a simple reversible one-electron reduction is observed leading to the formation of the stable semi-fluorescein radical anion. On irradiation with 390 nm light, appreciable photocurrents are observed and the process takes on the characteristics of a DISP reaction with the formation of leucofluorescein: the two-electron reduction product. Analysis of the e.s.r. signal-photocurrent-solution flow-rate data allows the precise mechanism of the reaction to be deduced, and this is shown to involve a rate-determining electron transfer between excited and ground-state semi-fluorescein molecules. |
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