COORDINATION-NUMBER, SYMMETRY OF THE COORDINATION SPHERE OF TIN(IV) AND OLIGOMERIZATION IN CARBOHYDRATE COMPLEXES OF DIBUTYLTIN(IV)

Dibutyltin(IV) complexes with 19 different carbohydrates were prepared and studied by Mossbauer spectroscopy. Comparison of the experimental quadrupole splitting values with those calculated on the basis of the partial quadrupole splitting concept revealed that the complexes are of four types: with the central tin(IV) atoms surrounded by donor atom s in a trigonal-bipyramidal, octahedral, both a trigonal-bipyramidal a nd octahedral or a tetrahedral arrangement. This procedure also distin guished between the different structural isomers of both trigonal-bipy ramidal and octahedral complexes. Conclusions could therefore be drawn as to the factors determining which of the isomers is formed in the s ystems. The changes in the room-temperature Debye-Waller factors and t he integral intensities of the Mossbauer doublets assigned to the tin( IV) in different surroundings reflected the oligomerization in the sys tems. The Mossbauer spectra revealed a temperature-dependent Goldanski -Karyagin effect.