Soluble high-molecular-weight polysilanes preparation

The discovery that soluble high molecular weight polysilanes may be prepared by the reductive coupling of dichlorodialkylsilanes by alkali metals (1,2) has led to considerable work on the properties of this interesting class of polymers (3,4,5). The preparation of the polymers leaves much to be desired as frequently the high polymer is only a minor product. Mechanistic studies of the reaction with a view to improving the relevant yields have been few (6). The major ones by Zeigler (7,8,9) showed that a silylene diradical was not involved in the reaction, and stressed the importance of polymer solvent interactions. 

Soluble polysilane polymers of high molecular weight were first prepared several years ago (1-3). The method commonly used is the reductive coupling of dialkyldichlorosilanes with sodium in refluxing toluene. Relatively few studies of the mechanism of the reaction or discussions of the probable reaction intermediates have been reported. 

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