Investigation of nitrogen-containing heterocyclic free radicals
Abstract2-(β-Naphthyl)-3,4-diphenyl-5-(p-R-phenyl)pyrroles were synthesized in order to study the effect of polycyclic substituents on the stability of free radicals of the tetraphenylpyrryl series. Benzene solutions of these radicals were oxidized with lead dioxide to obtain the corresponding radicals. The rates of decolorization of the latter in air are described by a second-order equation with respect to the radical. The introduction of a β-naphthyl substituent into the α position of the pyrrole ring in place of a phenyl group increases the stability of the radicals.