Equilibrium measurements for silver(I) complexes with polyamines in dimethyl sulphoxide

Abstract

The stability constants of silver(I) complexes with 1,2-diaminoethane (en), 1,3-diaminopropane (tn), and diethylenetriamine (dien) in dimethyl sulphoxide (dmso) at 25 °C and at an ionic strength of 0.1 mol dm^–3 have been determined by potentiometry. Within the silver and ligand concentration ranges investigated, two mononuclear complexes have been found for the Ag⁺–en and –dien systems; with tn, polynuclear complexes are formed in addition to a mononuclear species. The ligands all behave as chelating agents, en forming a five-membered chelate ring and tn a six-membered one; dien co-ordinates as a terdentate ligand. All the complexes are stronger in dmso than in water. The effects of the two solvents on the interaction between silver(I) and N-donor ligands are discussed.