A two‐dimensional cadmium(II) coordination polymer based on 5‐(pyridin‐4‐yl)isophthalic acid: poly[[tetraaquabis[μ3‐5‐(pyridin‐4‐yl)isophthalato]dicadmium(II)] pentahydrate]

The title CdII compound, {[Cd2(C13H7NO4)2(H2O)4]·5H2O}n, was synthesized by the hydrothermal reaction of Cd(NO3)2·4H2O and 5‐(pyridin‐4‐yl)isophthalic acid (H2L). The asymmetric unit contains two crystallographically independent CdII cations, two deprotonated L2− ligands, four coordinated water molecules and five isolated water molecules. One of the CdII cations adopts a six‐coordinate octahedral coordination geometry involving three O atoms from one bidentate chelating and one monodentate carboxylate group of two different L2− ligands, one N atom of another L2− ligand and two coordinated water molecules. The second CdII cation adopts a seven‐coordinate pentagonal–bipyramidal coordination geometry involving four O atoms from two bidentate chelating carboxylate groups of two different L2− ligands, one N atom of another L2− ligand and two coordinated water molecules. Each L2− ligand bridges three CdII cations and, likewise, each CdII cation connects to three L2− ligands, giving rise to a two‐dimensional graphite‐like 63 layer structure. These two‐dimensional layers are further linked by O—H...O hydrogen‐bonding interactions to form a three‐dimensional supramolecular architecture. The photoluminescence properties of the title compound were also investigated.