Tetraaqua(4,4′-dimethyl-2,2′-bipyridine-κ2N,N′)nickel(II) sulfate monohydrate: a simple molecule with an extremely complex hydrogen-bonding scheme

Abstract

The title ionic compound, [Ni(C12H12N2)(H2O)4]SO4·H2O, is composed of an NiIIcation coordinated by a chelating 4,4′-dimethyl-2,2′-bipyridine ligandviaits two N atoms [mean Ni—N = 2.056 (2) Å] and by four aqua ligands [mean Ni—O = 2.073 (9) Å], the net charge being balanced by an external sulfate anion. The whole structure is stabilized by a solvent water molecule. Even though the individual constituents are rather featureless, they generate an extremely complex supramolecular structure consisting of a central hydrogen-bonded two-dimensional hydrophilic nucleus made up of complex cations, sulfate anions and coordinated and solvent water molecules, with pendant hydrophobic 4,4′-dimethyl-2,2′-bipyridine ligands which interact laterally with their neighboursviaπ–π interactions. The structure is compared with closely related analogues in the literature.