Di-μ-chlorido-bis­[(2,2′-bipyridine-5,5′-dicarb­oxy­lic acid-κ²N,N′)chloridocopper(II)] dimethyl­formamide tetra­solvate

In the title compound, [Cu₂Cl₄(C₁₂H₈N₂O₄)₂]·4C₃H₇NO, 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].