catena-Poly[{μ(3)-4,4′,6,6′-tetra­chloro-2,2′-[butane-1,4-diylbis(nitrilo­methanyl­yl­idene)]diphenolato}{μ(2)-4,4′,6,6′-tetra­chloro-2,2′-[butane-1,4-diylbis(nitrilo­methanylyl­idene)]diphenolato}dicopper(II)]

The asymmetric unit of the title compound, [Cu(2)(C(18)H(14)Cl(4)N(2)O(2))(2)](n), contains two independent Cu(II) ions which are bridged by a pair of 4,4′,6,6′-tetra­chloro-2,2′-[butane-1,4-diylbis(nitrilo­methanylyl­idene)]diphenolate ligands, forming a dinuclear unit. One of the Cu(II) ions is coordinated in a distorted square-planar environment and the other is coordinated in a distorted square-pyramidal environment. The long apical Cu—O bond of the square-pyramidal coordinated Cu(II) ion is formed by a symmetry-related O atom, creating a one-dimensional polymer along [010]. In addition, short inter­molecular Cl⋯Cl distances [3.444 (2) Å] and weak π–π inter­actions [centroid–centroid distances = 3.736 (2)–3.875 (3) Å] are observed. The crystal studied was an inversion twin with a refined twin component ratio of 0.60 (1):0.40 (1).