(Invited) Modification of Lithium-Ion-Containing [60]Fullerene: Synthesis and Successful Preparation of Each [5,6]- and [6,6]-Isomer

Abstract

Lithium-ion-containing [60]fullerene, Li+@C60, is a highly electron accepting material, which have been utilized in electron transfer chemistry, supramolecular chemistry, photovoltaics, singlet oxygen generation, and so on. Considering what chemical modification of fullerene has played in, that for Li+@C60 would be a significant step for further functionalization of this compound.[1-7] In addition, chemical modification of Li+@C60 can solve this compound's drawback of low solubility in organic solvents due to rock salt packing of [Li+@C60][PF6 –]. Li+@C60 was modified with diphenyl(diazo)methane as an easily available diazoalkane to obtain lithium-ion-encapsulated [5,6]- and [6,6]-diphenylmethano[60]fullerenes, Li+@C61Ph2. Successful separation of each [5,6]- and [6,6]-isomer was performed with a positive-ion exchange columns. Both [5,6]-open and [6,6]-closed structures of Li+@C61Ph2 were determined with X-ray crystallographic analysis. Figure 1