Evaluation of antiradical activity of Schiff bases

Antioxidant activity of seven Schiff bases (SBs) was studied. The antiradical activity of SBs was determined by the chemiluminescence method from the interception of peroxyl radicals in the model reaction of initiated oxidation of ethylbenzene. The mechanism of inhibition of chain oxidation by SBs is poorly studied, but the addition of peroxyl radicals to the carbon atom with the disclosure of the conjugated double bond of the aldimine group -CH=N- seems to be most probable. This mechanism can be predominant one and determining the reactivity of SBs in the reaction with the rate constant (kinh): RO2• + [-CH=N-]→[-CH(RO2)-N•-]. 3-Hydroxy-2-(N-phenyliminomethyl)benzo[b]thiophene and its dimer manifested high anti-oxidant activity, and their inhibition activity is 3.43 • 105 and 7.5 • 105 L mol−1 s−1, respectively.