An optical spectroscopic study on carbon- and oxygen-centered free radical adducts trapped by a bi-functional nitrone spin trap

A hydroxylated nitrone spin trap, α-(3,5-di-tert-butyl-4-hydroxyphenyl)-N-tert-butylnitrone (BHBN), produces distinctive free radical products upon reaction with carbon- and oxygen-centered free radicals. Free radicals were generated from various compounds by photolytic and thermal decomposition. Such free radical-distinctive spin trapping has been previously studied using electron spin resonance spectroscopy, whereas we investigated this trapping reaction using absorption spectral measurements in the visible region. We determined characteristic absorption bands and molar extinction coefficients of the free radical products, and estimated the thermal decomposition rate of dibenzoyl peroxide, based on an optical spectroscopic study in spin trapping method.