The thermodynamic metal–ligand stability constants of hydroxamic acids with some divalent metal ions

Abstract

The thermodynamic metal–ligand stability constants of N-(m-chlorophenyl)-p-substituted benzohydroxamic acids with Pd^II, Cu^II, Zn^II, Ni^II, Co^II, Fe^II, and Mn^II have been determined at 25 °C in 50%(v/v) dioxane–water medium.

The stability of the complexes mostly follows the order of basicity of the ligands and also the electron-affinity of the metal ions, measured by their ionization potential. The free energy relationship, thermodynamic parameters, transition contraction energy, and ligand field stabilization energy of the complexes have been calculated.

In all the studies made here, the metal–ligand stability constants follow the order: Pd^II > Cu^II > Zn^II > Ni^II > Co^II > Fe^II > Mn^II.