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A STUDY OF PHOTOCHEMISTRY OF FLAVINS IN PYRIDINE AND WITH A DONOR *
Author(s) -
Kurtin William E.,
Latino Michael A.,
Song PillSoon
Publication year - 1967
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.1751-1097.1967.tb08812.x
Subject(s) - photochemistry , chemistry , photodissociation , pyridine , quantum yield , reactivity (psychology) , singlet oxygen , kinetic isotope effect , flavin group , intersystem crossing , triplet state , solvent , singlet state , molecule , excited state , oxygen , fluorescence , medicinal chemistry , organic chemistry , medicine , physics , alternative medicine , pathology , quantum mechanics , deuterium , nuclear physics , enzyme
— Both anaerobic and aerobic photolysis of riboflavin in pyridine yielded several photoproducts, analogous to the photochemical reaction in aqueous solution. Lumiflavin was also photoreduced in pyridine (an electron donor) without decomposition of the isoall‐oxazine ring Differences in the reactivity of excited singlet and triplet states with respect to formation of photoproducts have been confirmed in pyridine. In the photoreduction of riboflavin by N, N'‐dimethyl‐N‐benzylethylene diamine, an initial rate with a higher relative quantum yield than that of the reaction at a later stage was observed both in water and pyridine. Photolysis in D 2 O with the donor showed no significant solvent isotope effect. These results strongly suggest that the photolysis of riboflavin in water does not involve the water molecule in the primary photochemical act. A detailed mechanism of flavin photoreaction in water to account for solvent oxygen incorporation into a photoproduct (benzaldehyde) from N, N'‐dimethyl‐N‐benzylethylene diamine has been proposed without involving photochemical splitting of water based on our results and molecular orbital computations. Preliminary results on the kinetics of free radical decay were obtained using an ESR spectrometer and the significance of the results are discussed.