8-Hydroxyquinolinium trichlorido(pyridine-2,6-dicarboxylic acid-κ<sup>3</sup> <i>O</i>,<i>N</i>,<i>O</i>′)copper(II) dihydrate
Abstract
The title compound, (C 9 H 8 NO)[CuCl 3 (C 7 H 5 NO 4 )]·2H 2 O, was prepared by reacting Cu II acetate dihydrate, solid 8-hydroxyquinoline (8-HQ), and solid pyridine-2,6-dicarboxylic acid (H 2 pydc), in a 1:1:1 molar ratio, in an aqueous solution of dilute hydrochloric acid. The Cu II atom exhibits a distorted CuO 2 NCl 3 octahedral geometry, coordinating two oxygen atoms and one nitrogen atom from the tridentate H 2 pydc ligand and three chloride atoms; the nitrogen 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 molecules. The crystal structure features strong O—H...O and O—H...Cl hydrogen bonds as well as weak interactions 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 interactions, contributing 40.3% for the anion. Weak H...H contacts contribute 13.2% for the cation and 28.6% for the anion.