Functionalization of [60]fullerene through fullerene cation intermediates

Abstract

Fullerene cations, namely [60]fullerene radical cation (C₆₀˙⁺) and organo[60]fullerenyl cation (RC₆₀⁺), are less investigated as intermediates in synthetic fullerene chemistry because of the intrinsic electronegativity of C₆₀. Remarkably, these two intermediates can mediate reactions that afford versatile, unique and unexpected fullerene derivatives. This review article mainly describes these C₆₀˙⁺ and RC₆₀⁺ intermediates and includes a variety of topics, from the generation of C₆₀˙⁺ and RC₆₀⁺ species to their applications in fullerene modification reactions, such as Friedel–Crafts hydroarylation, nucleophilic addition, dimerization, intramolecular rearrangement reactions, and intramolecular cyclization reactions. Additionally, this review deeply discusses the mechanism of the formation of unique [60]fullerene derivatives involving [60]fullerene radical cation and organo[60]fullerenyl cation intermediates. In addition, the electrochemical properties and photovoltaic performance of these fullerene derivatives produced through C₆₀˙⁺ or RC₆₀⁺-mediated reactions are discussed in this review.