Diorganotin(IV) Complexes with Methionine Methyl Ester. Equilibria and Displacement by DNA Constituents
The coordination of methionine methyl ester with dimethyltin(IV) (DMT), dibutyltin(IV) (DBT) and diphenyltin(IV) (DPT) was investigated at 25 °C and 0.1 mol dm–3 ionic strength in water for dimethyltin(IV) and in 50 % dioxane–water mixture for dibutyltin(IV) and diphenyltin(IV). Methionine methyl ester forms1:1 and 1:2 complexes with diorganotin(IV). The corresponding formation constants were calculated by using the non-linear least-squares programMINIQUAD-75. The concentration distribution of the various complex species was evaluated as a function of pH. The displacement of coordinated methionine methyl ester with some DNA constituents was calculated based on equilibrium aspects.
KEYWORDS: Dimethyltin(IV), dibutyltin(IV), diphenyltin(IV), methionine methyl ester, stability constant.