Thermodynamic, Stability, Potentiometric and Solution Studies of Mixed Metal Complexes Involving Transition Metals and EGTA Ligand

Ethylene glycol-bis (2-aminoethylether) -N, N, N, N-tetraacetic acid [EGTA] is a multidentate ligand bear several application in medical science. In order to draw inference on their complexation behaviour and solution studies in mixed metal systems involving this ligand with Nickle, Lead, Cobalt and Copper have been carried using pH- metric titration technique in aqueous medium at three different ionic strengths (=0.05, 0.10, 0.15M) and at two different temperature 20c and 30C. SCOGS computer program was applied for computation. Protonated and non-protonated mixed metal ligand complexes are inferred to be formed through multiple equilibria. Distribution of various species is presented in the form of speciation curves. The two metals are coordinated to the ligand ion simultaneously in a single step. logK values support the formation of ternary complexes.