Synthesis of Benzothieno[60]fullerenes Through Fullerenyl Cation Intermediates.
Journal
JOC (Journal of Organic Chemistry)
Date
2019.04.22
Abstract
Benzothieno[60]fullerenes were synthesized by using fullerenyl cation key intermediates. The reaction proceeded through a nucleophilic attack of the sulfur atom as a weak nucleophile to the fullerenyl cation electrophile. A monoarylated fullerene, (2-methylthiophenyl)hydro[60]fullerene, C60ArH (Ar = C6H4-SMe-2, and so on; four derivatives) was subjected to deprotonation with KOtBu to form a fullerenyl anion ArC60？, followed by oxidation using I2 to generate a fullerenyl cation ArC60+ leading to intramolecular demethylative cyclization via fullerene cation？S interaction to the product. Electrochemical study elucidated low-lying LUMO level of this compound. Computational calculation revealed high-lying HOMO level due to the fused thieno moiety, giving relatively narrower band gap than usual fullerene derivatives.