SELF-INDUCED, PHOTOCHEMICAL, SINGLET-OXYGEN OXIDATION OF 4-NITROBENZENESULFENATES TO 4-NITROBENZENESULFINATES

It has been previously reported that the photo-induced homolytic disso ciation of homoallyl an 4-nitrobenzenesulfenates, followed by beta-sci ssion of the alkoxy radicals to allyl and alkyl radicals leads to the formation of sulfides. In the presence of dioxygen the alkyl sulfenate s undergo oxidation to the corresponding alkyl sulfinates. The results of theoretical studies suggest that the absorption of the photon resu lts in the excitation of an electron from the pi-type sulfur nonbonded -pair MO (the HOMO) to a pi MO of the aromatic ring (the LUMO). Quenc hing studies indicate that a triplet excited state is ultimately forme d which then reacts with triplet dioxygen to form singlet dioxygen, wh ich can be trapped with 1,3-cyclohexadiene, which then reacts with gro und-state sulfenate.