Synthesis, Characterization, and Functions of Novel Silicon-Containing Polyacetylenes

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The present project has dealt with the synthesis of novel, high-molecular-weight polymers form Si-containing acetylenes, elucidation of unique properties of the polymers, and exploitation of their functions. The results are summarized as follows:1. Synthesis and Characterization of Polymers from 3-(Trimethylsilyl)-1-alkyne Polymerization of four kinds of 3-(trimethylsilyl)-1-alkynes [HC<congruent>CCH(SiMe_3)R; R= CH_3, n-C_3H_7,n-C_5H_<11>, and n-C_7H_<15>) was examined. New polymers were obtained in high yields from these monomers in the pressence of Mo, W, and Nb catalysts. Every polymer was a yellow solid, whose structure could be expressed by [CH=CCH(SiMe_3)R_n]. Thepolymer with R = n-C_5H_<11> had high molecular weights up to 45x10^4, dissolved in many common organic solvents such as toluene and chloroform, and afforded a membrane by solution casting. The electrical conductivity of this polymer was 10^<-18> S.cm^<-1>, and its unpaired-electron density was <1x10^<15> spin/g. Further, the gas permeability ofthe polymer was investigated.2. Polymerization of Silylacetylenes and Polymer Properties Polymerization of five kinds of trimethylsilylacetylene homologues (HC<congruent>CSiMe_2R; R = n-C_6H_<13>, CH_2CH_2Ph, CH_2Ph, Ph, and t-Bu) was examined. Every monomer produced a polymer in the presence of suitable W catalysts. The polymers were yellow solids or rubbers. The polymers with flexible groups (R = n-C_6H_<13>, CH_2CH_2Ph, and CH_2Ph) were totally soluble in organic solvents, and their molecular weights were around 1x10^4.3. Polymerization of 3-Silyl-1-hexyne and Polymer Properties Two kinds of novel Si-containing monosubstituted acetylenes [HC<congruent>CCH(SiMe_<>R)-n-C_3H_7; R = n-C_6H^3 and Ph) produced polymers (MW 1x10^5 - 4x10^5) in good yields in the presence of Mo, W, and Nb catalysts. Both polymers were yellow solids and soluble in many solvents. Thermal, mechanical, electrical, and magnetic properties of these polymers have been elucidated.