Self-assembly of (n)rotaxanes bearing dendritic stoppers

A synthetic process for the self-assembly of (2)-, (3)-, and (4)rotaxanes, integrating bis-p-phenylene-34-crown-10 as the ring component(s) surrounding bipyridinium-based dumbbell-shaped components with dendritic stoppers at both ends is presented. Due to the hydrophobic dendritic framework, these (n)rotaxanes are soluble in a wide variety of organic solvents, despite the polycationic natures of their bipyridinium-based backbones. There is a significant dependence of the rate of molecular shuttling action of the (2)rotaxane, upon the polarity of the media.