Synthesis and Thermal Properties of Regio‐ and Stereoregular Poly(silylene‐1,4‐phenylenevinylene)s

Polymerization of p‐(dimethylsilyl)phenylacetylene in toluene at 25 and 80°C using RhI(PPh₃)₃ as the catalyst afforded highly regio‐ and stereoregular poly(dimethylsilylene‐1,4‐phenylenevinylene)s (cis‐ 3 a and trans‐ 3 a ) containing 98% cis‐ and 99% trans‐vinylene moieties, respectively. Similarly, poly(butylmethylsilylene‐1,4‐phenylenevinylene)s ( 3 b with 91% cis‐ and 95% trans‐structures) and poly(diisopropylsilylene‐1,4‐phenylenevinylene) with 95% trans‐structure were synthesized. All polymers were soluble in common organic solvents. The trans‐type polymers showed red shifts and hyperchromic effects in the UV‐visible spectrum. The onset temperature of weight loss (T₀) of cis‐ 3 a was much higher than that of trans‐ 3 a .