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DITHIOPHENES AS SINGLET OXYGEN SENSITIZERS
Author(s) -
Gommers F. J.,
Barker J.,
Wynberg H.
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.tb02619.x
Subject(s) - singlet oxygen , chemistry , photochemistry , oxygen , singlet state , imidazole , stereochemistry , organic chemistry , excited state , physics , nuclear physics
— The nematicidal compounds, 5‐methyl‐2,2′dithienyl, 5‐phenyl‐2,2′‐dithienyl and 5,5′‐dichloro‐2,2′‐dithienyl, generate singlet oxygen upon photoactivation with near‐UV light. Two chloro‐substituted dithienylethenes have similar properties that are farless efficient. The nematode Aphelenchus avenae was rapidly killed by the photoactivated dithienyls under aerobic but not under anaerobic conditions,indicating that nematicidal activity of these compounds is related to their sensitizing properties. Furthermore,these nematodes did not expire in the presence of these compounds maintained in the dark. Sensitizing properties were studied by following the inhibition ofglucose–6‐phosphate dehydrogenase by the photoactivated compounds and protection of enzyme activity by various additions. Only singlet oxygen quenchers were effective. The enzyme was inactivated 3 to 4 times faster in D 2 0 compared to H 2 0.Bleaching of p‐nitrosodimethylaniline in the presence of imidazole and the dithiophenes and a specific reaction with the olefin adamantylideneadamantane were additional evidence of generation of singlet oxygen by the photoactivated compounds.