Nitroxide Radicals of some N-Phenyl Substituted 1,4- and 1,2-Phenylenediamines

 Several N-phenyl substituted 1,4- and 1,2-phenylenediamines were oxidized using \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} radicals and 3-chloroperbenzoic acid. EPR spectroscopy confirmed the generation of nitroxide radicals originating from the oxidation of the bridging -NH-group. No radical products suggesting the simultaneous reaction with the NH2-group were observed. Only in the case of 1,4-phenylenediamine, a low concentration of nitroxide radical H–NO\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}–C6H4–NH2 was obtained. In o-aminodiphenylnitroxide the steric effect of the NH2-group causes a partially asymmetrical spin density distribution in both phenyl rings.