Features of Reaction of p-Benzosemiquinone Radicals with Iron Salts

摘要

We have earlier examined some intracellular mechanisms of photoreactions of semiquinone radicals with various reagents by means of chemical nuclear polarization [1-3].In the present work we studied the reactions of para-benzosemiquinone radicals with Fe2(SO4)3 and Mohr's salts at the flash-photolysis. These reactions were carried out in the aqueous-alcoholic solutions (the water-propanol ratio 9:1 by volume) with neutral and acidic (pH = 4.6) media. To avoid the influence of the changing ionic strength we used solutions containing sodium sulfate (0.1 M). To prevent the occurrence of additional dark reactions of oxidation and reduction at the use of Fe2(SO4)3 we used p-benzoquinone as a source of the semiquinone radicals, and with Mohr's salt, hydroquinone. The pulse photoexcitation of hydroquinone or p-benzoquinone using a UFS-2 (280-350 nm) filter in the presence of the hydrogen donor (alcohol) leads to the formation of p-semiquinone radicals. At pH = 4.6 the semiquinone anion-radical Q~- forms.