Regioisomeric -[70]fullerene-fused lactones: Synthesis, characterization and solubility difference

Two types of regioisomeric alpha-[70]fullerene-fused lactones were synthesized from the reaction of C-70 with 2-alkylmalonates under basic conditions. The structures of the compounds were determined unambiguously by X-ray single crystal diffraction analysis, and the compounds were further characterized with HRMS, UV-vis, H-1 NMR and C-13 NMR spectroscopies. The reactions were followed by the in situ vis-NIR measurement to study the mechanism. Interestingly, a large solubility difference was shown between the two types of regioisomers. (C) 2020 Elsevier Ltd. All rights reserved.