Trends in Structure and Growth of Higher Fullerenes Isomer Structure of C₈₆ and C₈₈-

Abstract

Abstract The isomer structure and stability of higher fullerenes is one of the most interesting issues which might be closely related with general question how a fullerene cage structure is formed. In the present study, the structures of the higher fullerenes with the sizes of C86 and C88 are described based on UV/Visible/nearIR absorption spectra and 13C NMR measurements in solution. For well-understanding the structure and growth of higher fullerenes, the isomer-free samples were prepared for all isomers associated with the C86, and C88 cages by means of a multiple stage high performance liquid chromatography (HPLC). As a result, five different isomers for C86 and C88 were successfully isolated and characterized. For these five different isomers studied in the present work, 13C NMR measurements in solution straightforwardly gave a conclusion that three of them possess the cage structures with a C2 molecular symmetry and two with a Cs molecular symmetry. The possible specific candidates for these five isomers will be discussed on the basis of both the present experimental results and recent theoretical predictions. Key Words: FullerenesHigher Fullerenes13C NMR spectroscopyIsomer SeparationC86 fullereneC88 fullerene