POLYMERIC ORGANOSILICON SYSTEMS .27. PREPARATION AND REACTIONS OF POLY[(ETHOXYSILYLENE)PHENYLENES] AND THERMAL-PROPERTIES OF THE RESULTING POLYMERS

Treatment of (4-bromophenyl)diethoxymethylsilane with magnesium in THF gave poly[p-(ethoxymethylsilylene)phenylene] (1a) in 58% yield. Simil ar reactions of (4-bromophenyl)triethoxysilane and (3-bromophenyl)diet hoxymethylsilane with magnesium afforded poly[p-(diethoxysilylene)phen ylene] (1b) and poly[m-(ethoxymethylsilylene)phenylene] (1c) in 61% an d 27% yields, respectively. The Si-OEt bonds of polymer 1a could be re adily transformed into the Si-Cl bonds, by treating the polymer with e xcess acetyl chloride, while polymer 1b did not react with acetyl chlo ride. Treatment of polymers 1a-c with lithium aluminum hydride produce d the respective polymers having an Si-H bond. The polymers having an Si-OEt and Si-Cl bond readily reacted with a variety of nucleophiles, including Grignard reagents and organolithium reagents, to afford subs titution products. The thermal properties of the polymers thus obtaine d were investigated by thermogravimetric analysis in a nitrogen atmosp here.