Transition-metal-mediated benzylation of C60 with benzyl chlorides

Abstract

Benzyl bromides have been widely used for fullerene functionalization. However, the use of benzyl chlorides, a more affordable but less reactive counterpart of benzyl bromides, has been rarely reported. Herein, a new metal-mediated benzylation of C₆₀ with benzyl chlorides is presented. In this method, with the combinatorial use of Mn powder and Cu(OAc)₂, various benzyl chloride derivatives could react with C₆₀ to afford 1,4-dibenzylated products in 12–53% yields. A mechanistic study by in situ visible near infrared (vis-NIR) spectroscopy and various control experiments suggests that, unlike the conventional anionic pathway that uses benzyl bromides, the transition-metal-mediated benzylation of C₆₀ with benzyl chlorides proceeds via a metal-mediated iterative single electron transfer process.