Cyclodextrin-covered organic nanotubes derived from self-assembly of dendrons and their supramolecular transformation.

The dendritic building blocks with a focal pyrene unit self-organize into vesicles in aqueous phase. The in situ inclusion of the focal pyrene units into the cavity of beta- or gamma-cyclodextrin (CD) induces self-assembled organic nanotubes with an average outer diameter of approximately 45 nm and inner diameter of 22 nm. The surface of the nanotube is covered with CD. Therefore, the functional group on the surface of the nanotube is controlled simply by modifying the functionality of CD. The removal of CD from the nanotube with poly(propylene glycol) reversibly generates vesicles. This work provides an efficient methodology not only to create an additional class of CD-covered organic nanotubes but also to exhibit reversible transformation of nanotubes and vesicles triggered by the motifs of dendron self-assembly, CD inclusion, and pseudorotaxane formation.