EQUILIBRIUM AND SPECTROSCOPIC STUDIES OF DIETHYLTIN(IV) COMPLEXES FORMED WITH CARBOHYDRATE-DERIVATIVES OF THIAZOLIDINE-4-CARBOXYLIC ACID

Coordination of six 2-substituted thiazolidine-4-carboxylic acid derivatives by the diethyltin(IV) cation was studied in aqueous solutions. The formation constants of the complexes MLH, ML and MLOH and of the hydrolysis products of diethyltin(IV) ion were determined by potentiometric equilibrium measurements. The ligands are effective complexing agents with amino acid type coordination in the pH>5 range, where the mixed hydroxo species MLOH predominates. The polyhydroxyalkyl substituents on the ligand do not show direct coordination to tin(IV), they exert only sterical effects on the process. The solid compounds with composition MLOH show, according to Mossbauer investigations based on the partial quadrupole splitting concept and according to IR spectroscopic studies, trigonal bipyramidal arrangement of the donor atoms around the tin(IV) ion with hydroxide, carboxylate and amine coordination.