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A FLASH PHOTOLYSIS STUDY OF 5‐METHOXYINDOLE
Author(s) -
Kuntz Robert R.,
Ponder Morgan,
Ghiron Camillo A.
Publication year - 1985
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1985.tb03461.x
Subject(s) - chemistry , flash photolysis , photoionization , microsecond , photochemistry , quenching (fluorescence) , fluorescence , oxygen , radical , photodissociation , analytical chemistry (journal) , ion , kinetics , ionization , reaction rate constant , chromatography , organic chemistry , physics , quantum mechanics , astronomy
— The microsecond flash photolysis of 5‐methoxyindole in aqueous solutions has been studied at γ exc ≥ 290 nm. Transients identified in this time realm in neutral solutions are: e aq ‐ , the 5‐methoxyindole radical cation (γ max ≅ 440 nm), the neutral transient with γ max ≅ 530 nm) and an unidentified oxygen sensitive transient with γ max ≅ 435 nm. Radical cations and e ‐ aq are shown to be produced in equal amounts consistent with a photoionization process as the only source of both transients. H + quenching of fluorescence and radical cation production gives equivalent Stern‐Volmer constants indicating that photoionization occurs from the fluorescent state. The unidentified oxygen sensitive transient exhibits a pK a of2–2.5 and is quenched at lower pH values indicating that it also has a fluorescent state precursor.