Syntheses and Characterization of Tributyltin(IV) Carboxylates Containing alpha-Oxoketene Cyclic Dithioacetals

摘要

Five aquatributyltin-2-(dialkylthio)methylene-3-oxo-5-aryl-4-pentenoates (3) were synthesized and characterized by IR spectra, ~1H NMR spectra, ~(13)C NMR spectra and elemental analyses. The IR spectra of (3) show strong O-H stretching modes in the region of 3384-3455 cm~(-1). In the H NMR spectra of (3), signals due to the protons of an alpha-oxoketene dithioacetal segment shift upfield compared to those of free acids (2). This is indicative of the formation of the tin ester complexes. The structure of 4-O_2N-C_6H_4CH=CHCOC(C_3H_4S_2)CO_2Sn(C_4H_9)_3 centre dot (H_2O) (3d) was determined by X-ray diffraction and showed two molecules in an asymmetric unit cell. The tin(IV) is coordinated with three carbon atoms, an oxygen of carboxylate and an oxygen of water and forms a five-coordinate, distorted trigonal bipyramidal configuration. There is no intermolecular O-Sn coordination in (3d), but a molecule of water acts as one of the five ligands and coordinates directly to the tin atom. The tin-oxygen (water) bond distance in (3d) is discussed in 'elation to that in other aquatin(IV) complexes.