Synthesis of Fullerene Derivatives with Novel Structures-Liquid-Phase versus Solid-State Reactions-

Abstract

Reactions of C60 with various carbon nucleophiles, particularly those with substituted acetylide and fluorenide ions in the liquid phase, give various C60 derivatives. While the reaction with cyanide salts only affords the cyanated C60 in liquid phase, the solid-state mechanochemical reaction selectively gives the dumbbell-shaped dimer. As typically shown by this example, the solid-state reaction was found to be quite advantageous for the formation of various types of fullerene dimers. The reaction of C60 with phthalazine also results in formation of entirely different products depending on the reaction phase. While the solid-state reaction gives a fullerene dimer incorporated in a bicyclic framework, the liquid-phase thermal reaction affords a derivative of an open-cage fullerene. Utilizing this reaction, an attempt has been made for organic synthesis of endohedral fullerene encapsulating molecular hydrogen through a series of procedures, i.e., opening a hole on the fullerene cage, insertion of molecular hydrogen, and reduction of the size of the opening.