Photooxygenation reactions anthracene

Carbon disulfide quenches the fluorescence of anthracene quite efficiently,145,149 but seems to have little effect on its triplet lifetime.147 Diphenylanthracene in benzene fluoresces with a quantum yield of 0.8 and shows a high sensitivity to the oxygen concentration in photooxygenation reactions. With about 1 vol% of CS2 present, AC>2 is practically independent of [02] (> 10"5 mole/liter). In jjoth cases, where carbon disulfide was either used as solvent or was added to an otherwise strongly fluorescent solution, the quantum yields of photooxygenation followed... 

However, even in the latter case (e.g., reaction of 1Oa + anthracene -> anthracene-endoperoxide), there seems to be no direct path from 1X to the stable endoperoxide, since all kinetic results have revealed the participation of two molecules of anthracene in the photooxygenation reaction. This also indicates that the excess energy, contained in 1X after transition from the F state, is used as kinetic energy with which 1S0 and 1Oa fly apart. 

Cyclopentadienes, 1,3-cyclohexadienes, 1,3-cycloheptadienes, as well as furan and aklyl-substituted furans, have been investigated as substrates of photosensitized oxygenation reactions, while aromatic compounds such as anthracenes and tetracenes as well as aryl-substituted carbo-and heterocyclic pentadienes were studied in direct and indirect (photosensitized) photooxygenation reactions. 

In comparison with the polymer bound sensitizers, the i micelle does not emit excimer emission. Furthermore, LCV is incorporated in micelle so that the loss of molecular motion in molecular aggregate state is not a serious drawback. However, side reaction of anthracene presumably photooxygenation at the 9, 10 position of anthracene is accelerated in micellar system. Results are summarized in Table 3. 

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