Complex Formation Reactions of Lanthanum(III), Cerium(III), Thorium(IV), Dioxouranyl(IV) Complexes with Tricine

Equilibrium studies for the heavy metal ions La(III), Ce(III), Th(IV) and UO₂(IV) (M) complexes of the zwitterionic buffer tricine (L) in aqueous solution are investigated. Stoichiometry and stability constants for the different complexes formed as well as hydrolysis products of the metal cations are determined at 25 °C and ionic strength 0.1 M NaNO₃. The stability of the formed complexes are discussed in terms of the nature of the heavy metal cation. The solid complexes are synthesized and characterized by means of elemental analysis, FTIR, and TG analysis. The general molecular formulae of the obtained complexes is suggested to be [M(L)₂](NO₃)_n-2(H₂O)_x, where n = the charge of the metal cation, x = no. of water molecules.