Di-μ-chlorido-bis­[(2,2′-bipyridine-5,5′-dicarb­oxy­lic acid-κ(2) N,N′)chloridocopper(II)] dimethyl­formamide tetra­solvate

In the title compound, [Cu(2)Cl(4)(C(12)H(8)N(2)O(4))(2)]·4C(3)H(7)NO, which contains a chloride-bridged centrosymmetric Cu(II) dimer, the Cu(II) atom is in a distorted square-pyramidal 4 + 1 coordination geometry defined by the N atoms of the chelating 2,2′-bipyridine ligand, a terminal chloride and two bridging chloride ligands. Of the two independent dimethyl­formamide mol­ecules, one is hydrogen bonded to a single –COOH group, while one links two adjacent –COOH groups via a strong accepted O—H⋯O and a weak donated C(O)—H⋯O hydrogen bond. Two of these last mol­ecules and the two –COOH groups form a centrosymmetric hydrogen-bonded ring in which the CH=O and the –COOH groups by disorder adopt two alternate orientations in a 0.44:0.56 ratio. These hydrogen bonds link the Cu(II) complex mol­ecules and the dimethyl­formamide solvent mol­ecules into infinite chains along [-111]. Slipped π–π stacking inter­actions between two centrosymmetric pyridine rings (centroid–centroid distance = 3.63 Å) contribute to the coherence of the structure along [0-11].