Laser flash photolysis of new water-soluble peroxyl radical precursor

Laser flash photolysis (LFP) of commercially available water-soluble 4-acetyl-4-phenylpiperidine hydrochloride (APP) in the presence of oxygen gives rise to acetylperoxyl radical (ACP). The formation of ACP during LFP of APP has been established by determining their rate constants with ABTS(2) in methanolic, and aqueous solutions (0.15+.0.02 and 2.0 +/- 0.2 x 10(9) M-1 s(-1), respectively), These rate constants are ill agreement with those reported in the literature. The reactivity of ACP was investigated with crocin in aqueous and methanolic solutions. Moreover, the rate constant for the reaction of ACP with nitrite anion (NO2) in aqueous Solution was determined to be 4.45 +/- 0.4 x 10(6) M-1 s(-1). Overall, APP can be used as ACP precursor in aqueous and organic Solutions using the more accessible LFP technique than the normally used (especially ill aqueous solutions) pulse radiolysis technique. (C) 2008 Elsevier B.V. All rights reserved.