Di­aqua­bis­­{μ-1,5-bis­­[(pyridin-2-yl)methyl­­idene]carbonohydrazide(1–)}di-μ-chlorido-tetra­chlorido­tetra­zinc(II)

A tetra­nuclear ZnII complex, [Zn4(C13H11N6O)2Cl6(H2O)2] or {[Zn2(HL)(H2O)(Cl2)](μCl)2[Zn2(HL)(H2O)(Cl)]}2, was synthesized by mixing an equimolar amount of a methanol solution containing ZnCl2 and a methanol solution containing the ligand H2L [1,5-bis­(pyridin-2-yl­methyl­ene)carbono­hydrazide]. In the tetra­nuclear complex, each of the two ligand mol­ecules forms a dinuclear unit that is connected to another dinuclear unit by two bridging chloride anions. In each dinuclear unit, one ZnII cation is penta­coordinated in a N2OCl2 in a distorted square-pyramidal geometry, while the other ZnII cation is hexa­coordinated in a N3OCl2 environment with a distorted octa­hedral geometry. The basal plane around the penta­coordinated ZnII cation is formed by one chloride anion, one oxygen atom, one imino nitro­gen atom and one pyridine nitro­gen atom with the apical position occupied by a chloride anion. The basal plane of the hexa­coordinated ZnII cation is formed by one chloride anion, one hydrazinyl nitro­gen atom, one imino nitro­gen atom and one pyridine nitro­gen atom with the apical positions occupied by a water oxygen atom and a bridged chloro anion from another dinuclear unit, leading to a tetra­nuclear complex. A series of intra­molecular C—H⋯Cl hydrogen bonds is observed in each tetra­nuclear unit. In the crystal, the tetra­nuclear units are connected by inter­molecular C—H⋯Cl, C—H⋯O and N—H⋯O hydrogen bonds, forming a planar two-dimensional structure in the ac plane.