A potential anti­cancer agent: 5-chloro-7-iodo-8-hy­droxy­quinolinium dichlorido(5-chloro-7-iodo­quinolin-8-olato-κ(2) N,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 anti­cancer agent. Its structure is ionic and consists of a square-planar [PdCl(2)(CQ)](−) complex anion (CQ is 5-chloro-7-iodo­quinolin-8-olate), with the Pd(II) 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.