Cyclophanes with self-recognising components

High dilution techniques have been employed to construct a series of charged flexible cyclophanes comprised of pi-electron-rich hydroquinone and pi-electron-deficient bipyridinium residues linked by polyether spacer units of varying length: significant conformational changes, leading to intramolecular and intermolecular interactions between the pi-donors and pi-acceptors, have been observed-as evidenced by X-ray crystallographic and variable temperature H-1 NMR and 2D ROESY spectroscopic investigations-within the series of the cyclophanes both in the solid and solution states as a result of increasing the lengths of the polyether spacer units.