Complex formation equilibria between 1,1,1-tris(N-methylaminomethyl)ethane and nickel(II), copper(II), zinc(II) and hydrogen ions

Abstract

The reactions of 1,1,1-tris(N-methylaminomethyl) ethane (Me 3tame) with nickel(II), copper(II), zinc(II) and hydrogen ions have been studied at 298 K in aqueous solution (0.5 mol dm −3 KNO 3) using potentiometric techniques. The equilibrium constants have been calculated using the computer program MIQUV. The stepwise equilibrium constants were obtained by combining the cumulative constants. Both basicity and stability constants have been compared with those previously reported for the similar nonmethylated triamine 1,1,1-tris(aminomethyl)ethane (tame). Me 3tame is more basic than tame and forms less stable metal complexes. The ligand Me 3tame has little tendency to form protonated complexes and only [Cu(Me 3tame)H] 3+ was found.