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LIGHT‐INDUCED REDOXCYCLES OF FLAVINS IN VARIOUS ALCOHOL/ACETIC ACID MIXTURES
Author(s) -
Schmidt Werner
Publication year - 1982
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.1751-1097.1982.tb09491.x
Subject(s) - flavin group , oxidizing agent , chemistry , photochemistry , acetic acid , methanol , alcohol , ethanol , benzyl alcohol , spectroscopy , absorption (acoustics) , fluorescence spectroscopy , absorption spectroscopy , fluorescence , organic chemistry , catalysis , materials science , physics , quantum mechanics , composite material , enzyme
— By dual wavelength absorption spectroscopy and fluorimetry. a flavin photo‐redoxcycle never reported before has been observed in solvents composed of alcohols (methanol, ethanol, benzyl alcohol) and acetic acid. This cycle consists of a fast anaerobic photoreduction with a subsequent rcoxidation of the flavin as a dark reaction. The photoreduction process is not sensitive to the prescnce of water (up to 50 vol%), in contrast to the reoxidizing process, which is completely inhibited by 10 vol% of water. Furthermore. this photocycle is inhibited by esters. Negative activation energies of about 20 kJ/mol for both photoreduction and oxidation indicate complex molecular mechanisms. It is proposed that photoreduction of the flavin produces a highly volatile oxidizing agent responsible for the subsequent reoxidation. Photoreducing and oxidizing species remain to be identified.