Laser flash photolysis study of the reaction of the t-butoxyl radical with iron(II)

Alkoxyl radicals are important intermediates in processes of lipid peroxidation that react with many biologically relevant material exerting damage in cells. These radicals are readily formed from hydroperoxides in the presence of reduced transition metal ions. Because reaction of alkoxyl radicals plays an important role in many autoxidation processes, we decided to measure its kinetics. Tert-butoxyl radicals (t-BuO•) were generated by homolytic photodecomposition of di-tert-butylperoxide using ruby laser flashes at 347 nm. The reaction of t-BuO• radicals with Fe2+ was studied under pseudo-first order conditions. The quantum yield of iron(III) was determined by measuring the absorbance of Fe3+ ion as (FeCl)2+ complex at 360 nm 2 us after the flash. The influence of the medium acidity on the rate constant was considered. All results will be summarized and discussed in terms of the stability of t-BuO• radical at different acidity and polarity of the medium.