Bis-p-xylyl[26]crown-6/pyridinium ion recognition: one-pot synthesis of molecular shuttles

Simple one-pot syntheses allow the preparation of [2]rotaxane-based degenerate molecular shuttles featuring the recognition of pyridinium ions by BPX26C6 macrocycles. Because of the weak interactions between the BPX26C6 and pyridinium units in the [2]rotaxanes in CD3COCD3, the rates of shuttling of the BPX26C6 moieties between the pyridinium stations are rapid, relative to those of DB24C8-based shuttles, on the NMR spectroscopic time scale at ambient temperature.