Polysilyne

{{Short description|Class of silicon polymers with the repeating unit [RSi]}}

In organosilicon chemistry, polysilynes are chemical compounds with the formula {{chem2|[RSi]_{n}|}}, where R can be hydrogen (e.g. in polysilyne {{chem2|[HSi]_{n}|}}), or organyl (e.g. in poly(methylsilyne)). Although their name suggests a relationship to alkynes ({{chem2|\sC\tC\s}}), polysilynes are a class of silicon-based random network polymers primarily composed of tetrahedral silicon atoms, each connected to one hydrogen or carbon and three Si atoms. These compounds are prepared by Wurtz coupling of alkyltrichlorosilanes ({{chem2|RSiCl3}}):

:{{chem2|3 Na + RSiCl3 -> [RSi]_{n} + 3 NaCl}}

The methyl and hexyl derivatives have been described.{{cite journal | last1 = Bianconi | first1 = Patricia A. | last2 = Weidman | first2 = Timothy W. | year = 1988 | title = Poly(n-hexylsilyne) synthesis and properties of the first alkyl silicon [RSi]_n network polymer | journal = J. Am. Chem. Soc. | volume = 110 | pages = 2342–2344 | doi = 10.1021/ja00215a077 }} Poly(methylsilyne) (PMSy) {{chem2|[CH3Si]_{n}|}} is a dark yellow powder.{{US patent|6989428}} "Methods of preparing polysilynes" With some solvents (tetrahydrofuran, ether, toluene etc.) it forms a colloidal suspension that is clear and non-viscous, which may then be deposited as a film or coating on various substrates.

Poly(methylsilyne) is a preceramic polymer, converting to silicon carbide upon thermolysis in an inert atmosphere. The optical properties of these materials has attracted attention.{{cite journal|title=Luminescence of Silicon Materials: Chains, Sheets, Nanocrystals, Nanowires, Microcrystals, and Porous Silicon

|author=Brus, Louis|journal=Journal of Physical Chemistry|year=1994|volume=98|pages=3575–81|doi=10.1021/j100065a007}}