A tautomerisable macrocyclic compound containing two aza-bridged 2,2′-bipyridine moieties

Abstract

A novel macrocyclic compound containing two aza-bridged 2,2′-bipyridine moieties was prepared by the templated reaction of 6,6′-dichloro-2,2′-bipyridine. Spectroscopic investigation shows that the aza-bridging atoms form an amine ⇌; imine tautomeric system. The tautomerism is dependent upon the solvent; the imine form is preferred in non-polar solvents such as chloroform and benzene, while the amine form is favoured almost exclusively in polar solvents such as water, alcohol, acetonitrile, dimethyl sulphoxide, or tetrahydrofuran.