Holder, S.J. and Achilleos, M. (2008) An oligosilane initiator for the Wurtz-type polymerisation of dichloromethylphenylsilane. Journal of Organometallic Chemistry, 693 (10). pp. 1938-1944. ISSN 0022-328X.
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1-Chloro-4-methyl-1,1,2,2,3,3,4,4-octaphenyltetrasilane was employed as an initiator in the Wurtz-type reductive coupling polymerisations of dichloromethylphenylsilane with sodium in toluene at 65 degrees C. Yields of polymethylphenylsilane (PMPS) were in the range 32-35% which was almost double that obtained by otherwise identical reactions in the absence of the initiator (16-19%). Furthermore, higher molecular weight parameters were observed for PMPS synthesised with the initiator. This is believed to be a result of the low reduction potential of the oligosilane allowing for it to compete efficiently in the initiation step with the dichloromethylphenylsilane monomer and inhibit end-biting, which usually occurs in conventional syntheses by reaction of the silyl anion with the terminal silicon-chlorine bond in the early stages of the polymerisation. Si-29 NMR spectroscopic analysis of an isolated high molecular weight fraction supported the incorporation of the oligosilane in the PMPS chain. In contrast, the use of the initiator in the Wurtz-reductive coupling of dichloromethylphenylsilane in tetrahydrofuran at room temperature led to no increase in molecular weights or yields of PMPS which confirms that the end-biting reaction is not as significant in polymerisations carried out under these conditions.
|Uncontrolled keywords:||polysilane; oligosilane; initiator; mechanism; polymerisation|
|Subjects:||Q Science > QD Chemistry|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group|
|Depositing User:||Simon Holder|
|Date Deposited:||27 Mar 2009 17:28|
|Last Modified:||14 Jan 2010 14:46|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/11731 (The current URI for this page, for reference purposes)|
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