INTERACTIONS OF ORGANOTIN(IV) HALIDES WITH REDUCED GLUTATHIONE IN AQUEOUS-SOLUTION

Glutathione (GSH) is a compound extremely common among many living organisms in which it plays a fundamental role in the processes of detoxification. Also, organotin(IV) derivatives are more and more commonly used in technological processes or as antitumor drugs. So it seemed interesting to investigate the possible interactions between GSH and organotin compounds in water. Particularly, it has been studied because of its role in the organic radicals linked to the tin center on the stoichiometry and the structure of the adducts. Information was obtained following the reaction between MenSnCl4-n (n = 1 to 3) and GSH by Mossbauer and NMR spectroscopies on the assumption that changes of the characteristic parameters such as the quadrupole splitting and the chemical shift and coupling constants, respectively, are closely related to modifications in the coordination of the tin atom. In the case of addition of GSH to a solution of CH3SnCl3 in HEPES, complex equilibria are evidenced, while in the case of Me2SnCl2 and of Me3SnCl only a single species is present. Mossbauer effect data together with point charge calculations and H-1 NMR results point to a 2:1 and a 1:1 complex, respectively; GSH is coordinated by the S(thiolic) atom and the coordination geometry around the tin center appears to be trigonal bipyramidal