Tetra-kis(μ(2)-2-methyl-3,5-dinitro-benzoato-κO:O)bis-[aqua-copper(II)] tetra-hydrate

The title compound, [Cu(2)(C(8)H(5)N(2)O(6))(4)(H(2)O)(2)]·4H(2)O, forms a centrosymmetric paddle-wheel-type dimer with an intra-molecular Cu⋯Cu distance of 2.6540 (4) Å. The Cu(II) atom is in a square-pyramidal coordination environment formed by four O atoms of four carboxyl-ate groups and one water mol-ecule, which is located in the apical position. The carboxyl-ate groups are twisted relative to the benzene rings by 11.09 (16) and 45.55 (19)°. The nitro groups are not coplanar with the parent aromatic rings [dihedral angles = 16.2 (3)-51.45 (14)°]. O-H⋯O hydrogen bonds between the coordinated water mol-ecules and one of the nitro groups, as well as π-π stacking inter-actions [centroid-centroid distance = 3.5764 (12) Å] between the benzene rings, assemble the complex mol-ecules into a one-dimensional polymeric structure which is further extended into a three-dimensional polymeric network via O-H⋯O hydrogen bonds involving the water molecules of crystallization.