Eosin photooxidation

The scope extends to certain aromatic compounds such as phenanthrene. Besides those dienes and aromatic rings that can be photooxidized directly, there is a larger group that give the reaction in the presence of a photosensitizer such as eosin (see... 

It has recently been shown by Spikes150 that uracil and a number of substituted uracils are subject to dye-sensitized photooxidation under certain conditions. Methylene blue and Eosin Y were active photosensitizers in the pH range 8-11.5, but were inactive below pH 8. FMN was very active over the pH range of 2.4-11.5. Photooxidation was measured with a rotating platinum oxygen electrode. 

Photooxidation of Eosin with periodate ion has been used to initiate the polymerization of acrylonitrile in aqueous solution [187]. Addition of acrylonitrile to a periodate solution shifts the absorption maximum from 220 to 280 nm. This spectral change is interpreted as being due to complex formation between the monomer and oxidizing agent. The rate of photopolymerization increases linearly with the absorbed light intensity and monomer concentration. The observed intensity dependence indicates the main chain terminator is not produced photochemically. Polymer is not formed when the concentration of periodate ion is lower than 0.5 mM and the rate of polymerization is independent of its concentration for higher values. 

Fluorescein and related quinonelike dyes such as eosin have found extensive use as low-energy sensitizers, especially in photooxidation studies. The efficiency of intersystem crossing in fluorescein varies markedly with pH. For the neutral molecule, the quantum yield of fluorescence is only 0.31, while it is 0.91 for the dianion.449 In strong acid solutions, however, protonated fluorescein is strongly phosphorescent. In this state (dissolved in boric acid) fluorescein was the first compound for which T-T absorption in an excited triplet state was observed.7... 

Photosensitized photooxidation of pyrrole (412) by irradiation in the presence of eosin gives rise to the photoproduct (413), presumably via the intermediate peroxide (414).440 Transannular peroxides are... 

Eosine-sensitized photooxidations have been carried out on heterocyclic A/-arylena-mines, resulting in the formation of the corresponding carbonyl compounds11. With the analogous quinoline derivatives, oxidation at the -carbon atom was also observed (Scheme 11). 

Poulios I, Micropoulu E. Panou et al. (2003), Photooxidation of eosin Y in the presence of semicoducting oxides. Appl Catal B Environ 41 345-355... 

Deerinck, T. J., Martone, M. E., Lev-Ram, V., Green, D. P. L.. Tsien, R. Y., Spector, D. L and Ellisman, M. H. (1994). Fluorescence photooxidation with eosin A method for high resolution immunolocalization and in silii hybridization detection for light and electron microscopy. J. Cell Biol. 126, 901-910. 

The eosin sensitized photooxidation of glaucine, dehydroglaucine, or nor-glaucine, in ethanol yields the corresponding oxoaporphine (9-methylatheroline in high yield. ... 

---