Ring opening, cyclosilanes

Cyclosilane ring opening Acoxysilanes from silanes... 

Polysilanes have been the first class of precursors used to prepare silicon carbide ceramics. In all cases, on pyrolysis, polysilanes are converted into polycarbosilanes by a Kumada rearrangement prior to the formation of an amorphous silicon carbide network. Several synthetic routes including dehydro-polymerization, ring-opening polymerization of strained cyclosilanes, polymerization of masked disilenes, or base catalyzed disproportionation reactions of disilanes have been described to prepare linear or branched polysilanes but despite its drawbacks the Wurtz-coupling route remains the method applied most, especially to prepare linear polysilanes. 

Keyword Polysilanes / Cyclosilanes / Photolysis / Ring-Opening Polymerization... 

The remarkable electronic behavior of these materids has stimulated considerable effort to develop selective syntheses of polysilanes with well-defined structure. Typical synthetic procedures include the Wurtz coupling of dichlorosilanes,(5-5) anionic polymerization of masked disilenes, (9-72) anionic ring-opening polymerization of strained cyclosilanes,(i5-i7) electrochemical reduction of chlorosilanes,(75-27) and transition metal catalyzed dehydrogenative coupling of phenylsilanes (eq. l).(22-55)... 

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