FLASH PHOTOLYSIS STUDY OF THE REACTIONS BETWEEN PHOTOEXCITED FLUORESCEIN (AND SIMILAR DYES) AND SELECTED SUBSTRATES WHICH ARE ON THE ONE HAND ELECTRON DONORS AND ON THE OTHER HAND ELECTRON ACCEPTORS
Abstract:
Primary processes occurring in the photo-oxidation and photoreduction of xanthene and acridine dyes in aqueous solutions were studied by means of the flash photolysis technique. Intermediary products were characterized. The triplet state of fluorescein, appearing in the photolysis of the dye in deoxygenated H2SO4 was studied with respect to absorption pectrum and decay rate. Photo oxidation of fluorescein by oxygen was studied in acidic as well as in alkaline solution. Photo oxidation of fluorescein by ironIII was studied in 0.1 to 10 M H2SO4. Dye photo-sensitized reduction-oxidation reaction between ironIII and ethylenediamine tetraacetic is reported. The semioxidized form of fluorescein appeared in the photo-oxidation of fluorescein by duroquinone as well as in the preceeding reaction. Influence of the carboxyl group of fluorescein on the photo chemical activity of the dye and the photoactivity of xanthene dyes were investigated.