A one-dimensional heterometallic coordination polymer with a three-dimensional supra­molecular framework: poly[μ₂-aqua-diaqua­(2,2′-bipyrid­yl)(μ₅-2-sulfonato­butane­dioato)copper(II)sodium(I)]

The title compound, [CuNa(C₄H₃O₇S)(C₁₀H₈N₂)(H₂O)₃]_n, consists of one Cu^II cation, one Na^I cation, one 2-sulfonato­butane­dioate trianion (SSC³⁻), one 2,2′-bipyridyl (bpy) ligand and three coordinated water mol­ecules as the building unit. The coordination of the Cu^II cation is composed of two pyridyl N atoms, one water O atom and two carboxyl­ate O atoms in a distorted square-pyramidal coordination geometry with an axial elongation. The Na^I cation is six-coordinated by three water mol­ecules and three carboxyl­ate O atoms from three SSC³⁻ ligands in a distorted octa­hedral geometry. Two SSC³⁻ ligands link two Cu^II cations to form a Cu₂(SSC)₂(bpy)₂ macrocyclic unit lying across an inversion centre, which is further linked by Na^I cations via Na—O bonds to give a one-dimensional chain. Inter­chain hydrogen bonds link these chains to form a two-dimensional layer, which is further extended into a three-dimensional supra­molecular framework through π–π stacking inter­actions. The thermal stability of the title compound has also been investigated.