Construction of a long cyclodextrin-based bis(molecular tube) from bis(polypseudorotaxane) and its capture of C60.

The preorganized bis(polypseudorotaxane) (approximately 20 nm long) formed by the multiple metallo-bridged poly(beta-cyclodextrin)s has been successfully converted to the lengthened bis(molecular tube) (approximately 200 nm long) through the intermolecular joining of approximately 10 discrete bis(polypseudorotaxane) units and the subsequent removal of the polymer templates. The obtained bis(molecular tube), which is quite soluble in water, dimethylformamide, and dimethyl sulfoxide, has been comprehensively characterized by NMR, gel permeation chromatography, static light scattering, X-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and scanning tunneling microscopy. Further investigations demonstrate that this bis(molecular tube) can capture C(60) through interaction with its many pi-electron-rich biquinolino groups.