The synthesis of organometallic rod-coil block copolymers from polysilanes

This mini-review gives a short summery of the chain-end chemistry of polysilanes, notably that leading to block copolymers. The anionic polymerisations of cyclotetrasilanes or 'masked' disilenes naturally lend themselves to the formation of polysilane-containing copolymers. A more robust, if less controlled, method results from the Wurtz-type reductive coupling reaction that yields polysilanes with silyl chloride chain-ends which are extremely sensitive to nucleophilic substitution. These may be used with appropriately functionalised polymers (such as polyisoprene or poly(ethylene oxide)) to prepare multiblock copolymers, or with functionalised groups designed as initiating centres for subsequent controlled reversible deactivation radical polymerisations (such as atom transfer radical polymerisation).