Cyclophanes with self-recognising components

Abstract

High dilution techniques have been employed to construct a series of charged flexible cyclophanes comprised of π-electron-rich hydroquinone and π-electron-deficient bipyridinium residues linked by polyether spacer units of varying length: significant conformational changes, leading to intramolecular and intermolecular interactions between the π-donors and π-acceptors, have been observed-as evidenced by X-ray crystallographic and variable temperature 1H 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.