Pulse radiolysis study of redox reactions of safranine T in aqueous solutions: One electron oxidation

• Published in: International journal of radiation applications and instrumentation. Part C, Radiation physics and chemistry Radiation physics and chemistry, 1992, Vol.39 (2), p.183-190
• Main Authors: Guha, S.N., Moorthy, P.N., Mittal, J.P.
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Radiation chemistry
• ISSN: 1359-0197; 1878-1020
• DOI: 10.1016/1359-0197(92)90039-I

One electron oxidation of safranine T by specific oxidizing radicals such as Cl - 2, Tl 2+, Tl(OH) +, N . 3, Br - 2 etc. has been studied using the nanosecond pulse radiolysis technique. Reaction of free Br . atom has also been investigated at neutral pH. The semioxidized safranine species formed by these reactions have been shown to exist in two conjugate acid-base forms with p K a=4.0. Their spectral and kinetic parameters have been evaluated. Using N . 3/N - 3 and I - 2/2I - as reference couples, the one electron reduction potential of the semioxidized safranine has been determined to be 1.13±0.02 V vs NHE. The absorption spectra, second order decay rate constant and the p K a of the OH-reaction product revealed features quite different from that of the semioxidized species suggesting that the mode of OH reaction is not via electron abstraction.