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Published on: February 27, 2017
Borane-catalysed postpolymerisation modification of the Si-H bonds in poly(phenylsilane)
1Department of Chemistry, University of Victoria, P. O. Box 1700, Stn CSC, Victoria, BC, Canada V8W 2Y2. lisarose@uvic.ca.
Dalton Transactions (Cambridge, England : 2003)
|April 1, 2017
Summary
Borane catalysis enables new sidechains on poly(phenylsilane) polymers, introducing diverse functionalities like Si-C and Si-O bonds while preserving the silicon backbone. This modification offers a versatile route to functionalized silicon-based materials.
Area of Science:
- Organometallic Chemistry
- Polymer Science
- Materials Science
Background:
- Poly(phenylsilane) is a silicon-based polymer with a unique silicon backbone.
- Functionalization of polysilanes is crucial for tailoring their properties.
- Existing methods for polysilane modification often lack selectivity or broad applicability.
Purpose of the Study:
- To explore the functionalization of poly(phenylsilane) using borane catalysis.
- To introduce diverse sidechains onto the polysilane backbone.
- To investigate the chemoselectivity and limitations of these catalytic reactions.
Main Methods:
- Utilized tris(pentafluorophenyl)borane [B(C6F5)3] as a catalyst.
- Performed hydrosilation, heterodehydrocoupling, and demethanative coupling reactions on Si-H bonds.
- Characterized modified polymers using NMR, IR, GPC, TGA, and UV-Vis spectroscopy.
Main Results:
- Successfully introduced 10-40% new sidechains, creating Si-C, Si-O, Si-N, and Si-S bonds.
- Confirmed preservation of the all-silicon backbone due to high chemoselectivity of B(C6F5)3 for Si-H over Si-Si bonds.
- Observed changes in UV-Vis spectra sensitive to new functional groups, though attenuated by residual Si-H.
- Identified limitations including substrate complexation and over-reduction, but demonstrated potential for higher substitution at elevated temperatures.
Conclusions:
- Borane-catalyzed reactions provide a versatile method for functionalizing poly(phenylsilane) with diverse sidechains.
- The high chemoselectivity ensures the integrity of the silicon backbone.
- Further optimization, including temperature control, can enhance the degree of functionalization.
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