Helically Organized Fullerene Array in a Supramolecular Polymer Main Chain

To date, supramolecular chemistry techniques have been applied to fullerene polymer synthesis, enabling the development of mainchain fullerene polymers whose primary structure is well regulated, including linear, dendritic, and net-like fullerene arrays. These research achievements have led to an intriguing scientific challenge to create main-chain fullerene polymers with higher structural regulation. Here, we report the fabrication of a helically organized fullerene array based on the supramolecular polymerization of chiral ditopic tetrakiscalix[5]arene hosts and a dumbbell-shaped fullerene. The molecular association between the chiral hosts and the dumbbell-shaped fullerene resulted in sizable supramolecular polymers in solution, with the highest degree of polymerization of more than 32. The achiral dumbbell-shaped fullerene exhibited circular dichroism in the pi-pi* transition bands arising from the fullerene moieties through supramolecular polymerization. End-capping experiments of the supramolecular helical polymers showed that the chirally twisted conformation of the dumbbell-shaped fullerene was directed by supramolecular polymerization. Finally, the helical morphology of the supramolecular polymer chain was visualized by atomic force microscopy. The successful development of helical main-chain fullerene polymers would break new ground in fullerene chemistry.

Automated summary

Supramolecular chemistry techniques have been utilized to synthesize helically organized fullerene arrays with high polymerization degrees, controlled by molecular interactions between chiral hosts and dumbbell-shaped fullerenes. The chirally twisted conformation of the dumbbell-shaped fullerene is directed by supramolecular polymerization, resulting in the visualization of helical morphology in the supramolecular polymer chain using atomic force microscopy. This successful development of helical main-chain fullerene polymers opens up new research avenues in fullerene chemistry.