FACTORS AFFECTING STABILITY AND EQUILIBRIA OF FREE-RADICALS .22. BOUND DISSOCIATION-ENERGY OF N-ALKOXYPOLYNITROANILINES

The homolitic bond dissociation energy (BDE) of the N-H bond for O2N(R (1))(R(2))Ar-NH-OR-type compounds 1 (a:R(1)=H, R(2)=NO2, R=CH3 b:R(1)= NO2; R(2)=H, R=CH3; c:R(1)=R(2)=NO2, R=CH3; d: R(1)=R(2)=NO2, R=iC(3)H (7)) which on oxidation yield the corresponding free radicals 2, has b een evaluated. For this purpose the equation: BDE = 1.37 pK(a) + 23.06 E(ox)(A(-)) + C has been used, by taking into account the pK(a) value s for the compounds 1 and the measured oxidation potentials of the typ e 3 anions (A) and of the supramolecular [18-crown-6...K](+) A(-) (A(- ) =3c). The oxidation of the salt 3 or of the supramolecular complexes 4 in polar solvents has evidenced by ESR the possibility of preparing the alkoxyaminyl radicals 2 in polar solvents from the corresponding anion.