Potentiometric determination of stability constants of salicylidine 3-amino-l, 2, 4-triazole trivalent lanthanide ion-complexes

الملخص EN

The acid dissociation constant of the Schiff base ligand salicylidine-3-amino-1,2,4-triazole in ethanolic solution was determined by pH-metric titration at 25°C and in different ionic strengths.

The overall stability constants of the chelates formed between this ligand and La(m), Ce(lll), and Ho(m) have been measured at two temperature degrees (25° & 35°C) have been investigated.

The free energies, enthalpies and entropies of the complexes formed were deduced.

The relation between the stabilities of these complexes and the ionic radius of the cations was discussed.