Electrophilic oxidant produced in the photodeoxygenation of 1,2-benzodiphenylene sulfoxide

We report that the photodeoxygenation of 1,2-benzodiphenylene sulfoxide, 1, generates an intermediate capable of oxidizing the solvent benzene to phen ol. The reactivity of the intermediate was probed with various substrates ( 2-methylbutane, chloride ion, and pare-substituted aryl sulfides). The inte rmediate produced in the sulfoxide photodeoxygenation displays an electroph ilic oxidation chemistry. Our data on 1 contrast with the behavior of hydro xyl radical but resemble the chemistry observed for gas-phase atomic oxygen [O(P-3)] and for solution-phase photodeoxy-genations of dibenzothiophene s ulfoxide, 3, and pyridine N-oxide, 5. Correlations are made between the ion ization potential of the acceptor molecules and the logarithm of the relati ve rate constants in order to advance the idea that the oxidizing agent of the title reaction may be solution-phase O(P-3).