Single-bonded fullerene dimers, (C60R)2 (R = (2-methoxyphenyl)dimethylsilylmethyl, (isopropoxy)dimethylsilylmethyl, and 2-methoxy-5-methylphenyl), afforded fullerene derivative cations (RC60+) in the presence of an oxidant (I2, CuCl2, or CuBr2), leading to 5- and 7-membered cyclofullerene derivatives such as cyclofullerenes containing a Si-O bond, cyclofullerenes containing a C60-O bond, and dihydrobenzofuranofullerene. The reaction mechanism involved thermal homolytic cleavage to give fullerene radicals, oxidation of the radicals to generate fullerene cations, and then demethylative cyclization in which the fullerene cationic centers interact with an aromatic group or the oxygen atoms of methoxy groups to produce the cyclized products. The obtained cyclofullerene derivatives were used in bulk-heterojunction organic solar cells and showed moderate power conversion efficiency and respectable open-circuit voltage.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)