Synthesis, structure, and properties of tert -butyl perfluorobiphenyl nitroxide

The reaction of perfluorobiphenyl with tert -butylamine in an autoclave affords the aminodefluorination product, N - tert -butyl-2,2′,3,3′,4′,5,5′,6,6′-nonafluorobiphenyl-4-amine, and the oxidation of the latter with meta -chloroperbenzoic acid gives the new stable nitroxide radical, N - tert -butyl- N -(2,2′,3,3′,4′,5,5′,6,6′-nonafluorobiphenyl)amine N -oxide, in quantitative yield. According to the X-ray diffraction analysis, the crystallization from heptane results in the spontaneous precipitation of the solid paramagnet as one of the two polymorphs, either triclinic ( P1̅) or monoclinic ( P 2 1 / n ). The electrochemical oxidation and reduction of nitroxide occur irreversibly. The heating of a toluene solution of the paramagnet leads to the oxidation of the solvent and the generation of the corresponding hydroxylamine and the benzyl radical, which enters into the recombination reaction with the initial radical to form alkoxyamine.