ChemInform Abstract: Structure/Property Relationships of Polystannanes

Publisher Summary This chapter focuses on the structure or property relationships of polystannanes. Distannane, which can be considered a heavy-atom analog of ethane, is the simplest chemical structure that falls under the preceding definition for the class of compounds known as polystannanes. It has long been known that the electronic spectrum of hexaphenyldistannane exhibits a strong absorption maximum, which has been attributed to the presence of the Sn–Sn bond in this compound. Sulfur and selenium can similarly be inserted into the Sn–Sn bond, and while peralkyl distannanes are typically more reactive than peraryl ones, bulky substituents can retard these reactions by raising energy barriers for bimolecular processes. The use of sterically demanding substituents is, in fact, the basis for a strategy known as kinetic stabilization, which has been successfully employed for the synthesis of polystannane frameworks that would normally have highly reactive Sn–Sn bond. Propellanes are a class of nonclassical structures, since they possess bridgehead atoms having formally inverted tetrahedral geometries that force the four bonds from each of the bridgehead atoms to lie within the same hemisphere. Given this configuration, theoretical investigations have long sought to determine the stability and reactivity of these molecular frameworks prior to the availability of representative synthetic derivatives.