8-Hy-droxy-quinolinium tri-chlorido-(pyridine-2,6-di-carb-oxy-lic acid-κ3 O,N,O')copper(II) dihydrate.

The title compound, (C9H8NO)[CuCl3(C7H5NO4)]·2H2O, was prepared by reacting CuII acetate dihydrate, solid 8-hy-droxy-quinoline (8-HQ), and solid pyridine-2,6-di-carb-oxy-lic acid (H2pydc), in a 1:1:1 molar ratio, in an aqueous solution of dilute hydro-chloric acid. The CuII atom exhibits a distorted CuO2NCl3 octa-hedral geometry, coordinating two oxygen atoms and one nitro-gen atom from the tridentate H2pydc ligand and three chloride atoms; the nitro-gen atom and one chloride atom occupy the axial positions with Cu-N and Cu-Cl bond lengths of 2.011 (2) Å and 2.2067 (9) Å, respectively. In the equatorial plane, the oxygen and chloride atoms are arranged in a cis configuration, with Cu-O bond lengths of 2.366 (2) and 2.424 (2) Å, and Cu-Cl bond lengths of 2.4190 (10) and 2.3688 (11) Å. The asymmetric unit contains 8-HQ+ as a counter-ion and two uncoordinated water mol-ecules. The crystal structure features strong O-H⋯O and O-H⋯Cl hydrogen bonds as well as weak inter-actions including C-H⋯O, C-H⋯Cl, Cu-Cl⋯π, and π-π, which result in a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing involving the main residues are from H⋯Cl/Cl⋯H inter-actions, contributing 40.3% for the anion. Weak H⋯H contacts contribute 13.2% for the cation and 28.6% for the anion.