ELECTROCHEMICAL AND SPECTROSCOPIC INVESTIGATION OF THE INFLUENCE OF ACID-BASE CHEMISTRY ON THE REDOX PROPERTIES OF 2,5-DIMERCAPTO-1,3,4-THIADIAZOLE

The UV-vis spectroscopy and cyclic voltammetry, of 2,5-dimercapto-1,3, 4-thiadiazole (DMcT) were studied in the absence and presence of pyrid ine (Py) or triethylamine (TEA) in acetonitrile solutions in order to. examine the influence of acid-base processes on the redox behavior of DMcT. In solutions containing Py, DMcT can be singly deprotonated to give the anionic species, DMcT(-). In solutions containing TEA, DMcT c an be either singly or doubly deprotonated to give the anionic species , DMcT(-), or the dianion, DMcT(2-), depending on the stoichiometry. T hese acid-base processes were monitored using UV-vis spectroscopy, and those results are reported here. The cyclic voltammetry of both syste ms was also examined in the absence and presence of Py or TEA. These e xperiments clearly showed that deprotonation of DMcT results in facili tation of its electrochemical oxidation, leading either to a disulfide -containing dimer or a disulfide-containing polymer, depending on cond itions. - Tile relevance of these results to the use of DMcT as a cath ode material in lithium secondary batteries is discussed.