Functionalization of [60]fullerene through fullerene cation intermediates

Fullerene cations, namely [60]fullerene radical cation (C-60(center dot+)) and organo[60]fullerenyl cation (RC60+), are less investigated as intermediates in synthetic fullerene chemistry because of the intrinsic electronegativity of C-60. Remarkably, these two intermediates can mediate reactions that afford versatile, unique and unexpected fullerene derivatives. This review article mainly describes these C-60(center dot+) and RC60+ intermediates and includes a variety of topics, from the generation of C-60(center dot+) 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 C-60(center dot+) or RC60+-mediated reactions are discussed in this review.