ULTRASONIC ENHANCEMENT OF ELECTROCHEMILUMINESCENCE FROM ARYLACETATE ELECTROOXIDATION

This paper describes the previously unreported electrogenerated chemil uminescence (ECL) from the electro-oxidation of several aryl carboxyla tes at a platinum flag electrode in aqueous, methanolic and acetonitri le solutions using tetramethylammonium hydroxide as a supporting elect rolyte. In most cases electrochemiluminescence was markedly enhanced b y simultaneous irradiation with ultrasound during electrolysis. Increa se in electrochemiluminescence intensity with electrolysis current and carboxylate concentration was observed. Addition of a radical scaveng er or purging of the solution with oxygen lowers ECL emission intensit y. In contrast the presence of oxygen enhances the intensity of sonolu minescence, which is a concurrent but weaker process occurring under u ltrasonic irradiation alone. Ring-substituted phenylacetates almost al ways produced less electrochemiluminescence than the unsubstituted par ent molecule, though within the substituents studied chloro-substitute d phenylacetates produced more ECL intensity than either methoxy- or n itro-substituted derivatives.