Spin trapping of oxygen-centred radicals by substituted N-benzylidene-tert-butylamine N-oxides

Abstract

Spin-trapping of oxygen-centred radicals (tert-butoxyl and carboxyl) by substituted N-benzylidene-tert-butylamine N-oxides (X-PBN) has been studied and the rates have been measured by means of EPR experiments. The experimental results revealed a substituent effect [X-PBN with an electron-donating substituent favours spin trapping (ρ < 0)] and are rationalized by an electron-transfer mechanism between the frontier orbitals of the reactants. The reaction pathway has been deduced from molecular-orbital and molecular-mechanics calculations.