"Helix-in-Helix" Superstructure Formation through Encapsulation of Fullerene-Bound Helical Peptides within a Helical...

A one-handed 3₁₀ -helical hexapeptide is efficiently encapsulated within the helical cavity of st-PMMA when a fullerene (C₆₀ ) derivative is introduced at the C-terminal end of the peptide. The encapsulation is accompanied by induction of a preferred-handed helical conformation in the st-PMMA backbone with the same-handedness as that of the hexapeptide to form a crystalline st-PMMA/peptide-C₆₀ inclusion complex with a unique optically active helix-in-helix structure. Although the st-PMMA is unable to encapsulate the 3₁₀ -helical peptide without the terminal C₆₀ unit, the helical hollow space of the st-PMMA is almost filled by the C₆₀ -bound peptides. This result suggests that the C₆₀ moiety can serve as a versatile molecular carrier of specific molecules and polymers in the helical cavity of the st-PMMA for the formation of an inclusion complex, thus producing unique supramolecular soft materials that cannot be prepared by other methods.