A DFT study on the self-coupling reactions of the three isomeric semiquinone radicals

Self-dimerisation of the three isomeric semiquinone radicals is considered herein. Optimised geometries and thermochemical parameters, in terms of heat of formation, entropy, heat capacity and Gibbs free energy of formation are provided for all possible cross coupling products. It is found that self-dimerisation of the three semiquinone radicals is not as thermodynamically favoured as the self-dimerisation of the phenoxy radical. Accordingly, the three isomeric semiquinone radicals can be regarded as less active precursors for the formation of dioxin compounds than phenoxy radicals.