Dioxiranyl radicals

The reactions of the diazine radicals with O2 were studied at the B3-LYP/6-311-1- G level (Scheme 59) [00JPC(A)6088]. Formation of dioxiranyl radical intermediates was found to be the most important pathway from the peroxy precursor. DFT-derived geometric parameters of pyrimidiniumolate are in good agreement with experimental data obtained for 1,2,3,5-tetraphenylpyrimidiniumolate [97MI1]. 

A subsequent study examined phenylperoxy radical in greater detail. Fadden et identified five possible unimolecular decomposition pathways for phenylperoxy radical (Fig. 10) via oxygen atom loss to form phenoxy radical (Fig. 10, route A), via a dioxiranyl radical species (Fig. 10, route B), via a dioxetanyl radical... 

The stability of 2-oxepinoxy radical qualified it as a target for further theoretical and experimental study. The calculations of Barckholtz et al. allowed the refinement of a feasible energetic pathway toward 2-oxepinoxy radical these DFT calculations supplemented the semiempirical work of Carpenter and also proposed a triradical intermediate between the dioxiranyl and oxepinoxy species (Fig. 9a). 

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