A one-dimensional coordination polymer based on a di-Schiff base supported trinuclear Cu^II subunit

A novel one-dimensional Cu^II coordination polymer, catena-poly[bis­(μ₄-3-{[2-(3-hydroxy-2-oxido­benzyl­idene)­hydrazinylidene]­methyl}­benzene-1,2-diolato)­dimethanol­tricopper(II)], [Cu₃(C₁₄H₁₀N₂O₄)₂(CH₃OH)₂]_n, (I), was constructed with a di-Schiff base supported centrosymmetric trinuclear Cu^II subunit. In the subunit, two peripheral symmetry-related Cu^II cations have square-pyramidal CuNO₄ geometry and the central third Cu^II cation lies on an inversion centre with octahedral CuN₂O₄ geometry. In (I), each partially deproton­ated di-Schiff base 3-{[2-(3-hydroxy-2-oxido­benzyl­idene)­hy­dra­zinyl­idene]­methyl}­benzene-1,2-diolate ligand (Hbcaz³⁻) acts as a hepta­dentate ligand to bind the Cu^II centres into chains along the a axis. A centrosymmetric Cu₂O₂ unit containing an asymmetrically bridging O atom, being axial at one Cu atom and equatorial at the other Cu atom, links the trinuclear Cu^II subunit into a one-dimensional chain, which is reinforced by intra­molecular phenol–methanol O—H...O and methanol–phenolate O—H...O hydrogen bonds. Interchain π–π stacking interactions between pyrocatechol units, with a distance of 3.5251 (18) Å, contribute to the stability of the crystal packing.