The mechanism for the cathodic reduction of sulphur in dimethylformamide: low temperature voltammetry

Using voltammetry at low temperatures, it is demonstrated that the reduction of sulphur (S8) in dimethylformamide (DMF) occurs in a 2e- step and the form of the voltammogram observed depends on the stability of the S82- formed. At 223 K, it is stable. In contrast, at ambient temperatures it cleaves rapidly to give two S4- anions and at more negative potentials, S4- is reduced further in a reversible 1e- process. The diffusion coefficient for S8 is a function of temperature and this leads to a substantial change to the current densities for the responses with temperature.