Solvent Effects on the Spectral and Electrochemical Properties of Some Pyridinium Quaternary Compounds

Abstract

The physicochemical properties and the redox potential of two pyridinium compounds, a diquaternary salt of 4,4�-bipyridinium (BP) and one of 1,2-bis(4-pyridyl)ethane (BPE) were studied. Cyclic voltammetry on platinum electrode was used to evaluate the solvent influence on the redox properties of the pyridinium compounds. Electrochemical measurements were performed in aqueous media, ethanol and aprotic solvent. The solvent variation causes changes in the electro-oxidation processes of the heterogeneous electron transfer at the applied potential. The presence of the ethylenic group in the structure of BPE presents slightly different electrochemical behaviour compared to BP. The corroboration of the electrochemical data with absorption spectral results attests that it�s more likely that the ECE sequence is responsible for the reduction mechanism of pyridinium compounds.