Reactions of the Triplet State of Duroquinone

Flash photolysis studies of duroquinone solutions in the presence and absence of triplet energy acceptors have established the triplet state of duroquinone as the precursor of the durosemiquinone radical. This contradicts the conclusions of Bridge and Porter and a reassignment of one of the transients first observed by these authors is suggested to explain this discrepancy. Experiments in which duroquinone solutions in isopropanol are subjected to continuous irradiation in the presence and absence of anthracene indicate that the triplet state is responsible for all detectable duroquinone photoconversions including those to give duroquinol and diduroquinone.