THE ELECTROCHEMICAL PROPERTIES OF SOME ALKYLVIOLOGENS

Ethyl-, and butylviologens were prepared by the Menschutkin reaction o f 4,4'-dipyridyl and 1,2-dibromoethane and 1,4-dibromobutane. Elementa l analysis and H-1-NMR spectra showed that products consisted of symme trical and asymmetrical substituted dipyridyls. Electrochemical reduct ion of these compounds in KBr and HCl solutions has been studied by th e voltammetry method. The reduction process proceeds through several e lectrochemical and protonation steps, depending on the viologen struct ure and pH of the solution. The process results in a film formation on the electrode surface. The film is partly electroactive in the KBr so lution, but completely passive in HCL. Reaction schemes have been prop osed to explain this phenomenon.