Spin trapping in heterogeneous electron transfer processes

Abstract

An overview of applications of spin trapping to electrochemical investigations is presented. Cited studies include characteriza­tions of primary electrode reaction products (e.g., electrooxidations of hal.ide and pseudohalide species, electroreduction of N-methylpyridinium ion) as well as the identification of transient intermediates arising from homogeneous reactions which are electroinitiated. The validity of spatially resolved spin trapping as a probe in the investigation of interfacial processes is demonstrated with examples drawn both from the previously reported co valent attachment of nitrone derived spin traps to silaceous surfaces and from recent studies of spin trapping in micelle and vesicle systems. Amphiphilic nitrone spin traps have been shown to coassemble with both micelles and vesicles such that the nitrone functionality resides in the interfacial region of the ordered system. The ability of these interfacially localized nitrones to trap transient radicals generated both in the hydrophobic domain of the micelle or vesicle and in the aqueous exterior domain is demonstrated.