Synthesis and Electrochemical Behavior of Regioisomeric Bismethanofullerene Derivatives

Abstract A series of regioisomeric bis-methanofullerenes (diethyl [60]fullerenobisacetate) were prepared by reaction of the sulfonium ylide with C60. Seven stable resultant regioisomers were completely isolated on a preparative HPLC and identified by FT-IR, UV-vis, TOF-MS, and 1H and 13C NMR measurements. The structures of these bisadducts were assigned based on 1) the relationship of the polarities of the regioisomers with the elution order from HPLC; 2) a comparison of their UV-vis spectra with those of corresponding Bingel-Hirsch bisadducts; and 3) the identification of their molecular symmetries by their 1H and 13C NMR spectra. The electrochemical properties of the resultant regioisomeric bismethanofullerene, derivatives were investigated through cyclic voltammetry (CV). The bisadducts exhibited more negative reduction potential than the pristine C60. Trans-2- and cis-3- bisadducts had the least negative potential E1 1/2 of all the other bisadducts.