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 (S-8) in dimethylformamide (DMF) occurs in a 2e(-) step and the form of the voltammogram observed depends on the stability of the S-8(2) formed. At 223 K, it is stable. In contrast, at ambient temperatures it cleaves rapidly to give two S-4 anions and at more negative potentials, S-4(-) is reduced further in a reversible 1e(-) process. The diffusion coefficient for S-8 is a function of temperature and this leads to a substantial change to the current densities for the responses with temperature. (C) 2001 Elsevier Science B.V. All rights reserved.