Complex Formation Reactions of Dimethyltin(IV) with Some Zwitterionic Buffers

Equilibrium studies in aqueous solution are reported for dimethyltin(IV) complexes of zwitterionic buffers, such as bicine and tricine (L). Stoichiometry and stability constants for the complexes formed were determined at 25°C and ionic strength 0.1M NaNO₃. The results showed the best fit of the titration curves were obtained for complexes MLH, ML, ML₂, MLH_-1, and MLH_-2 with the hydrolysis products of the dimethyltin(IV) cation. The bonding sites of the dimethyltin(IV) complexes with bicine and tricine at different pH were characterized in the solid state by elemental analyses, FTIR, and TG analysis. The molecular formula of the complexes synthesized at pH=3.0 is [(CH₃)₂Sn(L)(H₂O)]Cl while in neutral and alkaline media the hydrolytic species are formed.