ChemInform Abstract: Sulfur Radical Cations

Abstract

Sulfur radical cations are novel reaction intermediates that have attracted considerable attention recently. This in part is due to the renewed interest in the chemistry of radical cations in general, as well as four other factors. The first is the basis for understanding the structure and reactions of radical cations — can their inherent nature be best depicted by analogy with radicals, with cations, or is a new algorithm required? As is exemplified in this review, sulfur radical cations show novel behavior. Second, some reactions of sulfur radical cations are attracting interest for their application in organic synthesis. Third, biological electron-transfer may be mediated by sulfur and, indeed, sulfur radical cations may be intermediates in biological redox processes. Finally, materials based on tetrathiafulvalene, polythiophene, and related sulfur compounds have high electrical conductivity which may be understood in terms of p-delocalized sulfur radical cations or the related dications. Consequently, a comprehensive and critical review of this field appeared timely.