Electrochemical oxidation of a multisulfur compound

✍ Scribed by N.D. Canfield; J.Q. Chambers; D.L. Coffen

• Publisher: Elsevier Science
• Year: 1970
• Weight: 130 KB
• Volume: 24
• Category: Article
• ISSN: 0022-0728
• DOI: 10.1016/s0022-0728(70)80030-4

✦ Synopsis

Multisulfur heterocyclic compounds are often readily reduced and oxidized in contrast to the behavior of typical hydrocarbons. Usually the electrode processes are more complex than simple generation of a radical ion species. However, relatively few studies have been made to characterize the anodic and cathodic mechanistic pathways of sulfur compounds. Reference to recent authoritative reviews 1, 2 reveals that the majority of the studies in the literature have been concerned with generation of stable ion radicals and not with details of the more complex electrode processes. This communication reports the partial characterization of the anodic pathways of a complex multisulfur heterocycle.

The orthothiooxalate ( 1) is oxidized at a platinum electrode in a non.aqueous solvent in the region of 1.4 V vs. an aqueous SCE. Although a well defined limiting current is not observed, the anodic pathways can be partially characterized using the techniques of cyclic voltammetry, ring-disc electrode voltammetry, and electron spin resonance (e.s.r.) spectroscopy. Cyclic voltammograms of (1) in acetonitrile (Fig. 1) exhibit two reversible one-electron couple (E1/2 : 1.12 and 0.68 V vs, SCE) and an irreversible wave (Ep = ca. -0.1 V vs. SCE) on the cathodic segment of the potential sweep. The oxidation products which give rise to the reversible couples can be identified as the dication (4) and radical cation (3) of the bicyclic tetrathioethylene (2). Cyclic voltammograms of authentic samples of (2) exhibit two reversible one-electron oxidation waves superimposable with the -e -~ L 4-+ S 2 3 4