Polymerization of trimethylsilylacetylene by WCl6-based catalysts

The polymerization of trimethylsilylacetylene was investigated by using W and Mo catalysts. Mixtures of WCl₆ with appropriate organometallic cocatalysts such as n-Bu₄Sn and Et₃SiH at 1:1 molar ratio provided poly(trimethylsilylacetylene) in high yields. On the other hand, MoCI₅ gave mainly methanol-soluble oligomers even in the presence of these cocatalysts. The polymer formed was a partly insoluble yellow powder, and the molecular weight of the soluble fraction was about 7000. The IR, ¹H-NMR, and ¹³C-NMR spectra supported the polymer structure, (CH = CSiMe₃)_n. Protodesilylation of poly(trimethylsilylacetylene) afforded a new polymer containing both acetylene and trimethylsilylacetylene units.