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Contribution of Singlet Oxygen to the Photofading of Indigo
Author(s) -
KURAMOTO NOBUHIRO,
KITAO TEIJIRO
Publication year - 1979
Publication title -
journal of the society of dyers and colourists
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 0037-9859
DOI - 10.1111/j.1478-4408.1979.tb03480.x
Subject(s) - singlet oxygen , chemistry , photochemistry , rose bengal , oxygen , dabco , singlet state , porphyrin , catalysis , organic chemistry , excited state , physics , nuclear physics
The photofading of indigo in solution is examined. This photofading is accelerated in the presence of sensitizers of singlet oxygen, e. g. Methylene Blue or Rose Bengal. The fading is retarded by adding effective singlet oxygen quenchers, such as β–carotene, DABCO or nickel di–methyldithiocarbamate. In irradiations of both filtered (λ > 390 nm) and nnfiltered types, isatin is formed as the main photofading product. It is suggested that the photofading of indigo in solution may be due to a self–sensitized photo–oxidation involving singlet oxygen. By carrying out competitive photo–oxidation experiments in solution, the relative rate constant for the reaction with singlet oxygen is determined.