Synthesis of C₆₂N Containing a Heptagon

Chemical synthesis of nonclassical fullerenes is one of the remaining challenges in fullerene science. Until our recent report on the synthesis of C₆₄N, C₆₅N, and C₇₅N, there had been only limited examples such as conversion of C₆₀ into C₆₂. In this Letter, we showcase the synthesis of C₆₂N from C₆₀ through three steps. The crystal structure indicates that the C₆₂N fullerene possesses an N-containing heptagon, i.e., 2,7-dihydro-1H-azepine, on its sphere. The major axis reaches 8.735(5) Å, which is larger than that of C₆₀ by 23%. The reactivity and electronic properties of C₆₂N fullerene are also discussed.