[60]Fullerene-Based Macrocycle Ligands.

Macrocycle ligands have three or more donor sites. Selective replacement of skeleton carbon atoms by heteroatoms and vacancies in C60 could lead to various macrocycle ligands with a cage-shaped backbone. Theoretical calculations indicate that such C60 -based macrocycle ligands are as stable as C60 thermodynamically according to their similar HOMO-LUMO gaps. The synthesis of these ligands is a challenging task. Nevertheless important progresses have been reported. This concept article focuses on the structures of possible C60 -based macrocycle ligands and related synthetic results.