A conformationally persistent pseudo-bicyclic guanidinium for anion coordination as stabilized by dual intramolecular hydrogen bonds

Abstract

The first example of a pseudo-bicyclic guanidinium ligand is reported. When bound to an anion, the N,N′-bis(2-pyridyl)guanidinium cation persistently adopts the planar α,α conformation featuring intramolecular N⋯H–N–H⋯N hydrogen bonds in the solid state, which facilitates crystallization of sulphate from aqueous mixtures of anions.