| In the dissertation, the polymerization reactions of dichloro- and trichlorosilane, and trihydridosilane with substituent of trimethylsilylmethyl, {dollar}rm(CHsb3)sb3SiCHsb2,{dollar} group are studied.; Trimethylsilylmethyldichlorosilane, {dollar}rm(CHsb3)sb3SiCHsb2SiHClsb2,{dollar} is reduced with lithium, sodium, and sodium-potassium alloy under elevated temperatures or sonicating agitation. As expected, the condensation products of trimethylsilylmethyldichlorosilane are linear and cyclic polysilanes. Silane oligomers are obtained from the dehydrogenative coupling of trimethylsilylmethylsilane, {dollar}rm(CHsb3)sb3SiCHsb2SiHsb3,{dollar} when catalyzed with dimethyldipentacyclodienyl titanium, {dollar}rm Cpsb2TiMesb2,{dollar} but no polymerization products are obtained when catalyzed with a more reactive catalyst, {dollar}rm Cpsb2TiClsb2{dollar}/n-BuLi.; The work demonstrates that the reduction of trimethylsilylmethyltrichlorosilane, {dollar}rm(CHsb3)sb3SiCHsb2SiClsb3,{dollar} with alkali metals (lithium, sodium, and sodium-potassium alloy) unexpectedly leads to the formation of polycarbosilane instead of crosslinked or network polysilyne, (RSi){dollar}rmsb{lcub}n{rcub},{dollar} under conditions of elevated temperatures and sonication. The structure of the product is very complicated as shown by its mass spectra. The UV-visible spectra indicate there are no or only short Si-Si segments in the structure. FTIR and multinuclear NMR analysis are consistent with a polycarbosilane structure.; Mechanisms consistent with experimental results are proposed to explain the formation of polycarbosilane. Study on the reaction of bis(trimethylsilyl)mathane with trimethylsilyl anion supports the proposed mechanisms, however, the study on deuterium labeled trimethylsilylmethyltrichloro silane is unsuccessful yet. However, when trimethylsilylmethyltrichlorosilane is reduced with activated calcium, a milder reducing agent, Si-Si linkage forms.; Syntheses of tractable polysilane from pre-formed network silicon structures, as existed in some reactive metal silicides, remain a challenge to chemiss. In the attempted research, barium disilicide, BaSi{dollar}sb2,{dollar} which possesses a tetrahedral Si{dollar}sb4sp{lcub}4-{rcub}{dollar} structure, is treated with a variety of alkylating agents under elevated temperatures or sonication conditions. The desired alkylated compounds of (RSi){dollar}sb4{dollar} are not formed. Characterizations of barium disilicide and calcium disilicide, CaSi{dollar}sb2,{dollar} with solid state {dollar}sp{lcub}29{rcub}{dollar}Si NMR spectroscopy are reported in the dissertation. |
