PREPARATION AND STRUCTURAL STUDIES ON ORGANOTIN(IV) COMPLEXES WITH FLAVONOIDS

Fourteen complexes of di-n-butyltin(IV)(2+) cations with flavonoid gly cosides (rutin, hesperidin, 2',4',3-trihydroxy-5',4-dimetoxychalkone 4 -rutinoside) and flavonoid aglycones (quercetin, morin, hesperitin and sorte flavones) were prepared. The composition of the complexes was d etermined by standard analytical methods. The results showed that comp lexes containing diorganotin(lV)(2+) moiety and the ligand in 1:1, 2:1 or 3:1 ratio are formed. The FTIR spectra were consistent with the pr esence of Sn-O (phenol or carbohydrate) vibration in the compounds. Th e structure of the complexes was measured by Mossbauer spectroscopy. C omparison of the experimental quadrupole splitting with those calculat ed on the basis of partial quadrupole splitting concept revealed that the complexes are of four types: with the central tin atoms surrounded by donor atoms in a purely trigonal-bipyramidal, octahedral+trigonal- bipyramidal, trigonal-bipyramidal+tetrahedral and octahedral+tetrahedr al arrangement. This procedure also distinguished between the differen t structural isomers of both trigonal-bipyramidal and octahedral compl exes. Conclusions could therefore be drawn on the factors determining which of the isomers are formed in the systems. The Mossbauer paramete rs obtained for organotin(rv)-flavonoid complexes were compared with t hose measured for organotin(IV)-carbohydrate complexes.