Aqueous Equilibrium and Solution Structural Studies of the Interaction of N,N'-bis(4-imidazolymethyl)etylenediamine with Ca(II), Cd(II), Co(II), Cu(II), Mg(II), Mn(II), Ni(II), Pb(II) and Zn(II) Metal Ions

Divalent metal complexes of N,N'-bis(4-imidazolymethyl)etylenediamine (EMI) have been studied using potentiometric and spectroscopic techniques (UV-Vis and NMR methods) in aqueous 0.1 mola <...L-1 KCl supporting electrolyte at 25 A degrees C. Final models and overall stability constants for the complexes of Ca(II), Cd(II), Co(II), Cu(II), Mg(II), Mn(II), Ni(II), Pb(II) and Zn(II) have been established by potentiometry for all M(II)-EMI systems, except for Co(II)-EMI. The data revealed that EMI forms ML complexes with all M(II)-EMI systems, which is the dominant species over a wide range of pH except for the Ca(II)-EMI and Mg(II)-EMI systems. Formation of the MnHL complex was also found for Mn(II)-EMI solutions. In addition, the UV-Vis and H-1 NMR results allowed us establish the coordination modes for the metal complexes between EMI with Cd(II), Cu(II), Ni(II) and Zn(II).