Effects of ortho-substituents on the living polymerization of phenylacetylenes by MoOCl4-based catalysts

✍ Scribed by Tomohiro Mizumoto; Toshio Masuda; Toshinobu Higashimura

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 412 KB
• Volume: 196
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1995.021960531

✦ Synopsis

Polymerization of phenylacetylenes (PAS) having various ortho-substituents were examined by using MoOCI,-n-Bu,Sn-EtOH (mole ratio 1 : 1 : 1) as catalyst. Phenylacetylenes with no or sterically small ortho-substituents did not polymerize in a living fashion. On the other hand, in the polymerization of phenylacetylenes having medium-sized substituents (e. g., CH,, C1, Br, and iPr), the number-average molecular weights M, of polymers increased in direct proportion to monomer consumption, while the polydispersity ratios were 1,2-1,3, which is in favor of living polymerization. Further, monomers having bulky ortho-groups (CF, and Me,Ge) exhibited excellent living nature with small polydispersity ratios of = 1 , l . Thus, it is concluded that not the electronic but the steric effect of the ortho-substituent is important to achieve living polymerization.