On the Mechanism of Dimerization of Stable Organic Radicals

The dynamics of unpaired electron density versus reaction coordinate in the unsymmetrical dimerization of triphenylmethyl and diphenylaminyl radicals corresponds to single-electron transfer from the atom formally bearing the unpaired electron to the benzene ring. The formation of dimerization products is governed by the Coulomb interaction between the effective charges on atoms of the reacting system. In polar solvents, the transparency coefficient of the potential barrier to single-electron transfer decreases, which is responsible for the lack of unsymmetrical dimerization of radicals.