Potentiometric Study of Speciation and Thermodynamics of Complex Formation Equilibria of Diorganotin(IV) Dichloride with 1-(2-Aminoethyl)piperazine.

The interaction of DET (diethyltin(IV)) and DVT (divinyltin(IV)) with 1-(2-aminoethyl)piperazine (AEP) was investigated potentiometrically at different temperatures in 0.1 mol·dm NaNO. The hydrolysis constants of diethyltin(IV) and divinyltin(IV) cations and the stepwise formation constants of the complexes formed in solution were calculated at different temperatures and in solutions of dioxane-water solutions of different compositions. The stoichiometries and stability constants for the complexes formed are reported. The results show formation of 1:1 complexes and the corresponding hydroxide complexes. The concentration distributions of the various complex species were evaluated as a function of pH. The thermodynamic parameters Δ H° and Δ S° calculated from the temperature dependence of the equilibrium constants were investigated for DET and DVT complexes with AEP. [ABSTRACT FROM AUTHOR]