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SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF CYCLIC ORGANOTIN COORDINATION COMPOUNDS
Abstract
As a result of low energy d orbitals, tin(IV) frequently expands its coordination sphere beyond four by the formation of stable complexes with Lewis bases. The ability of tin(IV) compounds to form complexes is dependent on the electronegativities of the substituents attached to tin. The tin halides, SnX(,4), are well known for their ability to form coordination complexes but as the halogens are replaced by less electronegative organic groups the tendency to coordinate with Lewis bases decreases in the order RSnX(,3) > R(,2)SnX(,2) > R(,3)SnX > R(,4)Sn. The objective of this study was to provide information on the structural changes which occur in organotin compounds as the Lewis acid acceptor strength of tin changes. Six organotin coordination compounds were synthesized and subjected to single crystal X-ray structural analysis. The triorganotin species, (C(,6)H(,5))(,3)Sn(2-(NH(,2))C(,4)H(,6)CO(,2)), was found to have a distorted tetrahedral geometry around the tin atom. A moderate bonding interaction was observed between the carbonyl oxygen of the carboxylate group and the tin atom. In addition, one of the amine protons was found to be hydrogen bonded to the carbonyl oxygen. Three diorganotin compounds, (t-C(,4)H(,9))(,2)Sn(OCH(,2)CH(,2))(,2)NCH(,3), (CH(,3))(,2)Sn(SCH(,2)CH(,2))(,2)NCH(,3), and (C(,6)H(,5))(,2)Sn(Cl)S(,2)CN(CH(,3))(,2) were found to be five coordinated with distorted trigonal bipyramidal geometries around the tin atom. For each trigonal bipyramidal compound the most electronegative substituent was found to occupy an axial position. One diorganotin compound (n-Bu)(,2)SnOCH(,2)CH(,2)O, achieved a coordination number of six(' ) by intermolecular association. One monoorganotin compound, CH(,3)Sn(OCH(,2)CH(,2))(,3)N, was investigated. As a result of intermolecular tin-oxygen associations, a trimeric species containing two six-coordinated and one seven-coordinated tin atoms was formed. The coordination geometries of the six-coordinated tins are distorted octahedral, while for the seven-coordinated tin the geometry is distorted pentagonal bipyramidal. In addition, six water molecules are hydrogen bonded to oxygen atoms of the trimer, giving a molecular stoichiometry of {CH(,3)Sn(OCH(,2)CH(,2))(,3)N}(,3)(.)6H(,2)O. Comparisons of the above organotin compounds with structurally related compounds are made.
Subject Area
Chemistry
Recommended Citation
SWISHER, ROBERT GREGORY, "SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF CYCLIC ORGANOTIN COORDINATION COMPOUNDS" (1982). Doctoral Dissertations Available from Proquest. AAI8211056.
https://scholarworks.umass.edu/dissertations/AAI8211056