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CHLOROPHYLL‐SENSITIZED REDUCTION OF SAFRANINE
Author(s) -
Bannister T. T.
Publication year - 1963
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.1751-1097.1963.tb08909.x
Subject(s) - chemistry , photochemistry , chlorophyll , quenching (fluorescence) , chlorophyll fluorescence , ascorbic acid , fluorescence , photostationary state , chlorophyll a , biochemistry , organic chemistry , food science , optics , catalysis , isomerization , photoisomerization , physics
— The kinetics of the direct photoreduction, and the chlorophyll‐sensitized reduction, of safranine by ascorbic acid in aqueous pyridine was studied. In darkness following illumination, safranine was reformed from the colorless reduced derivative by a first order reaction. In light, however, the photostationary concentration of reduced safranine was proportional to the square root of the absorbed illumination, indicating a second order back reaction. The spectrum of reduced safranine, the inhibition of chlorophyll photoreduction by safranine, and the quenching of chlorophyll fluorescence by safranine were also measured. While other mechanisms of sensitization are conceivable, the simplest explanation of the results seems to be one involving the formation of the triplet state of safranine at the expense of the triplet state of chlorophyll.