The formation of protonated copper(II)-8-oxyquinoline complexes in aqueous solution

The constants of formation of copper-8-oxyquinoline complexes in aqueous solution (logβ) were determined using pH-metric titration combined with mathematical simulation for the following complexes: CuHOx²⁺ (14.39 ± 0.20), CuHOx ₂ ⁺ (25.25 ± 0.16), CuOx⁺ (10.07 ± 0.21), and CuOx₂ (20.92 ± 0.29); 293 K, I = 0.01. It was shown by UV spectrophotometry that, in protonated complexes, the metal atom is probably bound to the ligand through oxygen.