POLYMERIZATION OF PHENYLACETYLENES .19. EFFECTS OF ORGANOMETALLIC COCATALYSTS ON THE POLYMERIZATION OF DISUBSTITUTED ACETYLENES BY TACL5 AND NBCL5

The effects of organometallic cocatalysts on the polymerization of disubstituted acetylenes were investigated. Diphenylacetylene did not polymerize with TaCl//5 alone, while it produced a polymer quantitatively in the presence of appropriate cocatalysts (Me//4Sn, Et//3SiH, etc. ). The poly(diphenylacetylene) formed was an insoluble yellow solid. 1-Phenyl-1-alkynes (1-phenyl-1-butyne and -1-octyne) polymerized with TaCl//5 and NbCl//5 alone to yield polymers whose weight-average molecular weights (M OVER BAR //ws) were ca. 5 multiplied by 10**5. Various effects of organometallic cocatalysts were observed depending on the kind of monomer.