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    • Keywords


      One-electron reduction of thionine; pulse radiolysis; kinetic spectrophotometry; semithionine; thionine

    • Abstract


      One-electron reduction of thionine has been studied by using the technique of nanosecond pulse radiolysis and kinetic spectrophotometry. H,eaq as well as radicals derived from methanol, ethanol, isopropanol, THF, dioxane andt-butanol by H atom abstraction were used as reductants. The rate constants for the transfer of electrons from these radicalts to thionine were directly determined from the pseudo first-order formation rates of the product, semithionine and the one-electron reduction potential of thionine estimated. The absorption spectrum of semithionine in its different conjugate acid-base forms was found to be in agreement with previously reported spectra and the decay of the species was second order. By monitoring transient absorbance changes as a function of pH, twopKa values were observed and, based on the effect of ionic strength on the second-order decay constants of the species were assigned to the equilibria described.

    • Author Affiliations


      S N Guha1 P N Moorthy1 K Kishore1 D B Naik1 K N Rao1

      1. Chemistry Division, Bhabha Atomic Research Centre, Trombay, Bombay - 400 085, India
    • Dates

  • Journal of Chemical Sciences | News

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