Photosensitized formation of peroxyl radicals in aqueous solutions of adenine at 77 K

Photoinduced formation of peroxyl radicals in aqueous solutions of nucleobase derivatives at 77 K

“…The computation procedure was described in [5,9]. An analysis was performed for the spectra in which at least at two values of W = 200 μW and 2 mW were recorded.…”

“…Signals of the medium, belonging to (1) R1, free radicals O ; (2) R2, HO radicals [6,9]; (3) Cl [12]; (4) E, trapped electrons [13]; (5) NO [5].…”

“…Using this method, it was shown in [6,9] [2]. A peculiar feature of the low-temperature photolysis of the solutions of A is the formation of HO radicals at pH values far exceeding the value of pK a = 4.8 of HO ↔ O + H + equilibrium [10].…”

“…A peculiar feature of the low-temperature photolysis of the solutions of A is the formation of HO radicals at pH values far exceeding the value of pK a = 4.8 of HO ↔ O + H + equilibrium [10]. This was the basis for assuming there is way of HO formation that is different from of the superoxide formation, and that it probably lies in the acceptance of photo-ejected electrons by oxygen [9]. Table 1.…”

“…Φ f and Φ ph are the quantum yield of fluorescence and phosphorescence, respectively; τ is the phosphorescence lifetime. It was shown that in irradiated solutions of A + NaCl, the composition of paramagnetic products depends on the method of freezing, since the results differ in samples frozen in quartz ampoules and in samples with an open surface in contact with air during preparation and with liquid nitrogen upon irradiation ("open samples") [9]. We assumed that the key factors in the latter case are the adsorption of O 2 , the accumulation of hydroxyl ions, and the increased numbers of defect centers on the surface of the ice, as was shown in [11].…”