Nature of the transient species in the one-electron oxidation of diethyl dithiocarbamate as studied by pulse radiolysis

Abstract

One-electron oxidation of the diethyl dithiocarbamate (DDC) anion by oxidising radicals such as ˙OH, N₃˙, Br₂˙^–etc. has been studied employing the pulse radiolysis technique. The transient species absorbing in the visible region (λ_max 570 nm) has been identified as the dimer anion radical formed by the interaction of the initial neutral radical (Et₂NCS₂˙) with the parent anion. This species was found to be rather unreactive towards other solutes and decayed, with second-order kinetics, to give disulfiram. The reaction of disulfiram with hydrated electrons (e^–_aq) gave rise to the same transient spectrum as obtained in the case of one-electron oxidation of DDC. The reaction of e^–_aq with DDC at pH 9 gave a transient spectrum with λ_max 340 nm which has been attributed to a carbon-centred radical dianion (Et₂NCS₂˙^2–).