Chemistry of Polysilanes and Development of New Preparations

Recent applications of polysilanes as SiC precursors and photoinitiators, and in microlithography and reprography show that polysilanes are very much promising as specialty materials for high technology of the next generation. In this paper, the chemistry of polysilanes is reviewd with some emphasis on the physical properties. Recent progress on the preparation of high-molecular weight polysilanes is then described. Finally, hitherto unprecedented anionic polymerization of masked disilenes, developed recently in the author's laboratory, is discussed in detail. Thus, masked disilenes such as 1-phenyl-7, 8-disilabicyclo [2.2.2.] octa- 2, 5-dienes with alkyllithium led to the formation of the reactive living polysilylenyl anions R (SiR1R2SiR3R4) -n which gave the corresponding relatively monodispersed polysilanes upon quenching. The Mw/Mn values range from 1.3 to 1.9. The reaction of the living polysilylenyl anions with methyl methacrylate afforded well characterized block copolymers.