NEW MULTEDENTATE LIGANDS XII: Chelating Tendencies of N,N?-Ethylenediaminediacetic-N,N?-Diacethydroxamic Acid

Abstract
Quantitative equilibrium studies of a new multidentate ligand, N,N′-ethylenediaminediacetic-N,N′-diacethydroxamic acid (EDTA-DX, H4L) are described. Its acid-base and metal-ligand reaction stoichiometries have been determined and the corresponding proton and metal ion association constants have been calculated from potentiometric data. Stabilities of normal chelates MLn-4, and their protonation constants are reported for Mg(II),Co(n), Ni(II), Cu(II), Zn(II), and Fe(III), and an additional dissociation constant is determined for the iron chelate FeL-. The probable chelate structures in solution have been deduced by analysis of infrared and proton magnetic resonance spectra in D2O solution, and of electronic spectra in aqueous solution.