ELECTROCHEMISTRY OF 8,8'-DIQUINOLYLDISULFIDE

The electrochemistry of 8,8′-diquinolyldisulfide, RSSR, and mercuric thiooxinate, (RS)2Hg, has been investigated in methanolic-sodium acetate and aqueous 1.0M H2SO4, using conventional polarography, cyclic voltammetry, and controlled potential electrolysis. The data indicate that RSSR is not directly reduced at the DME but is adsorbed and then undergoes a fast precursor chemical reaction to form mercuric thiooxinate, (RS)2Hg, which is electroactive. Controlled potential electrolysis shows that the (RS)2Hg formed undergoes a 2e- reduction to give 8-mercaptoquinoline, RSH, as the major product while the oxidation of RSH gives (RS)2Hg. Although the chemical and adsorption equilibria involved in the reduction of RSSR and (RS)2- Hg are complex, the coulometric generation of RSH from either starting material is feasible and should facilitate the use of 8-mercaptoquinoline as an analytical reagent. © 1969, American Chemical Society. All rights reserved.