Towards moisture and light stable polystannanes

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Until relatively recently, studies of polymers of Group 14 elements have been largely limited to those containing carbon. While research interest into the unique properties of polymers based on heavier Group 14 elements, polysilanes, polygermanes, and polystannanes has continued to increase, applications with these materials has been considerably more limited. Higher Group 14 polymers are in general both light and moisture sensitive, making them more difficult to prepare, isolate and use compared to conventional polymer systems. The highest polymers of Group 14 metals (Sn, Pb) represent a relatively untapped research area with catenated lead polymers, polyplumbanes, still unknown. One of the unique properties of higher Group 14 polymers is the extensive delocalized sigma-sigma bond network created from overlap of elemental orbitals along the backbone, making these products optically and electronically interesting. The potential to make highly conductive films, one-dimensional quantum wires and printable electronics with homopolymers of Sn and Pb have not been explored. This research will address the previous synthetic shortcomings of these unique materials and deliver the first examples of moisture and light stable polystannanes. Light stability will be accomplished by the introduction of light stabilizing side groups (UV absorbers (UVA), hindered amine light stabilizers (HALS)) to protect the backbone from photoscission reactions. Moisture stability will be provided by the use of bulky hydrophobic or ring structures on the tin atom to improve resistance to moisture and other nucleophiles. Polymerization of the above described monomers will be accomplished by dehydrogenative coupling of alkyl or aryl tin dihydrides and Wurtz coupling and electropolymerization of alkyl or aryl tin dichlorides. Metal catalyzed insertion of unsaturated hydrocarbons, (alkynes or benzynes) into the backbone of these polymers will also be investigated. Characterization and applications testing of these new polymers will also be undertaken.