Chemical modeling studies of the speciation of co2+, cu2+ and zn2+ complexes of azelaic acid dihydrazide in aqueous medium

A potentiometric chemical speciation study was carried out on Azelaic acid dihydrazide (L)-divalent metal ion systems in aqueous medium. In solution the ligand was found to exist in neutral (L), mono protonated (LH+) and biprotonated (LH22+) forms. The best-fit models obtained for metal ion-dihydrazide systems using the Miniquad-75 program indicated the formation of mono and bimetallic species with different degrees of protonation and deprotonation. The formation of bimetallic species reflects the ditopic nature of the ligand. Species concentration distribution diagrams against pH of the solution were generated using the HYSS program.