スチルベン系螢光染料の光退色

概要

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The photofading of 4, 4'- bisacetamidostilbene (BAAS) in ethanol has been examined by both spectrophotometry and thin-layer chromatography. Irradiation of the trans isomer of BAAS in ethanol rapidly produced an eqilibrium mixture of cis and trans isomers. The observed ratio of cis/trans isomer was about 82/18 in the equilibrium state. Futher irradiation of the equilibrium solution caused, gradual decomposition of both trans and cis isomers to produce p-acetamidobenzaldehyde. Futher the photofading of trans and cis isomers in solution were examined. The photofading of trans was accelerated in the presence of sensitizers of singlet oxygen, e.g. Rose Bengal, but in the case of cis, scarecely accelerated. The fading of trans isomer retarded by adding effective singlet oxygen quenchers, such as β-carotene or nickel dimethyl-dithiocarbamate, but not by adding super oxide anion quencher, such as sodium sulfinate. In irradiations of both filtered (λ> 420nm or 520nm) and unfiltered types, p-acetamidobenzaldehyde and p-acetamidobenzoic acid were formed as the main photofading products. The photofading of BAAS in solution is suggested to be carryed out by attack of singlet oxygen toward trans-isomer in cis-trans equilibrium mixture of BAAS.
名古屋女子大学の論文
1982-03-31