Polymer Bulletin

, Volume 22, Issue 5–6, pp 441–448 | Cite as

Anions and radicals as intermediates in the reductive coupling of disubstituted dichlorosilanes with sodium

Trapping the intermediate radicals in polymerization of allyl- and hexenyldichlorosilanes
  • Hwan Kyu Kim
  • Krzysztof Matyjaszewski
Article

Summary

Polymerization of four monomers with alkenyl groups: allylmethyldichlorosilane, allylphenyldichlorosilane, 5-hexenylphenyldichlorosilane and 5-hexenylmethyldichlorosilane was studied by reductive coupling with sodium in the presence of ultrasound at ambient temperatures. Soluble homopolymers and copolymers with phenylmethyldichlorosilane with molecular weights Mn >10,000 were obtained for the first three monomers. UV and29Si NMR studies indicate a high degree of Si-Si catenation for allyl derivatives. Approximately half of the alkenyl groups remain in the polymer after a few hours. This indicates that after the formation of the polysilane backbone alkenyl groups are predominantly trapped intramolecularly in a process resembling cyclopolymerization of diallylsilanes. The main mechanistic conclusion is that in the reductive coupling process radicals are present as short living intermediates which are rapidly reduced to anions at higher polymerization degrees, but which are efficiently trapped at a monomeric or dimeric level. Thus, electron transfer proceeds in two one-electron transfer steps from a chloroterminated chain to a radical, and then to a macromolecular silyl anion. The latter reacts with a monomer via a nucleophilic substitution. Polymerization is an anionic chain growth process.

Keywords

Allyl Silyl Chain Growth Polymerization Degree Polysilane 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    R. West, in “Comprehensive Organometallic Chemistry”, G. A. Wilkinson, F. G. A. Stone and E. W. Abel, Eds., Pergamon Press, Oxford, 1983, Vol. 9, 365Google Scholar
  2. 2.
    R. West, J. Organomet. Chem.,300, 327 (1986)Google Scholar
  3. 3.
    J. M. Zeigler, Synthetic Metals,28, C581 (1989)Google Scholar
  4. 4.
    R. D. Miller, D. Hofer, D. R. McKean, C. G. Willson, R. West and P. Trefonas III, ACS Symp. Ser.,266, 293 (1984)Google Scholar
  5. 4.
    J. M. Zeigler, ACS Polymer Preprints27(1), 109 (1986)Google Scholar
  6. 5.
    K. Matyjaszewski, Y. L. Chen, H. K. Kim, ACS Symposium Series,360, 78 (1988)Google Scholar
  7. 6.
    K. Matyjaszewski and H. K. Kim, J. Am. Chem. Soc.,110, 3321 (1988)Google Scholar
  8. 7.
    H. Stüger and R. West, Macromolecules,18, 2348 (1985)Google Scholar
  9. 8.
    H. K. Kim, K. Matyjaszewski, Polymer Preprints30(1), 131 (1989)Google Scholar
  10. 9.
    S. Gauthier, D. Worsfold, Macromolecules22, 2213 (1989)Google Scholar
  11. 10.
    P. Trefonas III, R. West, R. D. Miller and D. Hofer, J. Polym. Sci., Polym. Lett. Ed.,21, 283 (1983)Google Scholar
  12. 11.
    D. A. Stanislawski and R. West, J. Organomet. Chem.,204, 295, (1981)Google Scholar
  13. 12.
    R. West, M. J. Fink, J. Michl, Science,214, 1343 (1981)Google Scholar
  14. 13.
    C. Chatgilialoglu, K. U. Ingold and J. C. Scaino, J. Am. Chem. Soc.,104, 5123 (1982)Google Scholar
  15. 14.
    C. Chatgilialoglu, K. U. Ingold and J. C. Scaino, J. Am. Chem. Soc.,105, 3292 (1982)Google Scholar
  16. 15.
    C. Chatgilialoglu, H. Woynar and K. U. Ingold, J. Chem. Soc., Perkin II1983, 555Google Scholar
  17. 16.
    T. J. Barton and A. Revis, J. Am. Chem. Soc.,106, 3802 (1984)Google Scholar
  18. 17.
    K. Saigo, K. Tateishi and H. Adachi, J. Polym. Sci., Polym. Chem. Ed.,26, 2085 (1988)Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Hwan Kyu Kim
    • 1
  • Krzysztof Matyjaszewski
    • 1
  1. 1.Department of ChemistryCarnegie Mellon UniversityPittsburghUSA

Personalised recommendations