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

The title ionic compound, [Ni(C₁₂H₁₂N₂)(H₂O)₄]SO₄·H₂O, is composed of an Ni^II cation coordinated by a chelating 4,4'-di­methyl-2,2'-bipyridine ligand via its 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 neighbours via [pi]-[pi] inter­actions. The structure is compared with closely related analogues in the literature.