KINETIC AND SPECTRAL PROPERTIES OF THE INTERMEDIATES FORMED IN THE PULSE-RADIOLYSIS OF 2-MERCAPTOBENZIMIDAZOLE

The reactions of primary species of water radiolysis such as e(aq)(-) H-. and (OH)-O-., and some specific one electron reductants and oxidants with 2-mercaptobenzimidazole have been studied at various pHs. (OH)-O-. radical reaction with MBZ at pH 7 gave a transient species having absorption maxima (lambda(max)) at 330 and 590 nm. The transient species (pK(a) = 3.6) was found to be neutral at this pH and was a mild oxidant. The initial transient species formed by the reaction of MBZ with e(aq)(-), at pH 7 and with H atom at pH O were found to react with the parent molecule to form another transient species which has an absorption spectrum similar to that obtained by (OH)-O-. radical reaction with lambda(max) at 590 nm. However the reaction is not quantitative. The kinetic, spectral, acid-base and redox properties of the transient species are reported.