Selective host-guest interaction of single-walled carbon nanotubes with functionalised fullerenes

Exohedrally functionalised fullerenes have been inserted in single-walled carbon nanotubes (SWNTs) with the aid of supercritical carbon dioxide to form peapods; C-61(COOEt)(2) are encapsulated in SWNTs in high yield, whereas C-61(COOH)(2) aggregate via hydrogen bonding to form a supramolecular complex, which sterically hinders encapsulation and causes it to adhere to the exterior surface of the SWNTs.