A novel two-dimensional coordination polymer: poly[diaquatetra-μ2-chlorido-[μ2-2,2'-(piperazine-1,4-diium-1,4-diyl)diacetate]dicadmium(II)].

In the crystal structure of the title two-dimensional metal-organic polymeric complex, [Cd2Cl4(C8H14N2O4)(H2O)2]n, the asymmetric unit contains a crystallographically independent Cd(II) cation, two chloride ligands, an aqua ligand and half a 2,2'-(piperazine-1,4-diium-1,4-diyl)diacetate (H2PDA) ligand, the piperazine ring centroid of which is located on a crystallographic inversion centre. Each Cd(II) centre is six-coordinated in an octahedral environment by an O atom from an H2PDA ligand and an O atom from an aqua ligand in a trans disposition, and by four chloride ligands arranged in the plane perpendicular to the O-Cd-O axis. The complex forms a two-dimensional layer polymer containing [CdCl2]n chains, which are interconnected into an extensive three-dimensional hydrogen-bonded network by C-H···O, C-H···Cl and O-H···O hydrogen bonds.