Co-ordination number, symmetry of the co-ordination sphere of tin(IV) and oligomerization in carbohydrate complexes of dibutyltin(IV)

Abstract

Dibutyltin(IV) complexes with 19 different carbohydrates were prepared and studied by Mössbauer 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 atoms in a trigonal-bipyramidal, octahedral, both a trigonal-bipyramidal and octahedral or a tetrahedral arrangement. This procedure also distinguished between the different structural isomers of both trigonal-bipyramidal and octahedral complexes. Conclusions could therefore be drawn as to the factors determining which of the isomers is formed in the systems. The changes in the room-temperature Debye–Waller factors and the integral intensities of the Mössbauer doublets assigned to the tin(IV) in different surroundings reflected the oligomerization in the systems. The Mössbauer spectra revealed a temperature-dependent Goldanski–Karyagin effect.