A potential anticancer agent: 5-chloro-7-iodo-8-hydroxyquinolinium dichlorido(5-chloro-7-iodoquinolin-8-olato-κ2N,O)palladium(II) dihydrate

The title PdII coordination compound, (C9H6ClINO)[PdCl2(C9H4ClINO)]·2H2O, was prepared as a potential anticancer agent. Its structure is ionic and consists of a square-planar [PdCl2(CQ)]− complex anion (CQ is 5-chloro-7-iodoquinolin-8-olate), with the PdII atom surrounded by two chloride ligands in a cis configuration and one N,O-bidentate CQ molecule, a protonated anion of CQ as counter-cation and two non-coordinated water molecules. The water molecules are involved in O—H...O and N—H...O hydrogen bonds, which interconnect the HCQ+ cations into a chain parallel to [010]. Apart from these interactions, the structure is also stabilized by face-to-face π–π interactions [centroid–centroid = 3.546 (3) Å], which occur between the phenolic parts of the complex anions and cations.