A potential anti-cancer agent: 5-chloro-7-iodo-8-hy-droxy-quinolinium dichlorido(5-chloro-7-iodo-quinolin-8-olato-κN,O)palladium(II) dihydrate.

The title Pd(II) coordination compound, (C(9)H(6)ClINO)[PdCl(2)(C(9)H(4)ClINO)]·2H(2)O, was prepared as a potential anti-cancer agent. Its structure is ionic and consists of a square-planar [PdCl(2)(CQ)](-) complex anion (CQ is 5-chloro-7-iodo-quinolin-8-olate), with the Pd(II) atom surrounded by two chloride ligands in a cis configuration and one N,O-bidentate CQ mol-ecule, a protonated anion of CQ as counter-cation and two non-coordinated water mol-ecules. The water mol-ecules are involved in O-H⋯O and N-H⋯O hydrogen bonds, which inter-connect the HCQ(+) cations into a chain parallel to [010]. Apart from these inter-actions, the structure is also stabilized by face-to-face π-π inter-actions [centroid-centroid = 3.546†(3)†à ], which occur between the phenolic parts of the complex anions and cations.