Controlled Polymerization of Acetylenic Monomers with Late Transition Metal Catalysts. (English)

Novel late transition metal catalysts for the controlled polymerization of acetylenic monomers are reported. Zwitterionic and cationic rhodium catalysts bearing tetrafluorobenzobarrelene (fib) as a highly π-acidic diene showed excellent activity for the polymerization of acetylenic monomers. The activity values of (tfb) Rh[(η 6 -Ph)BPh 3 ] and [(tfb)Rh(PPh 3 ) 2 ]BPh 4 are higher than those of the conventional analogues bearing 2,5-norbornadiene (nbd). The latter cationic tfb-rhodium catalyst achieves living polymerization of phenylacetylene and its ring-substituted derivatives in the presence of amines. The obtained polymers have a highly stereo-regulated main chain of cis-transoidal structure. The livingness of the polymerization of phenylacetylene with the binary catalyst composed of (tfb)Rh + [(η 6 -Ph)B - Ph 3 ] and i PrNH 2 was confirmed by the kinetic study and by multi-stage polymerization. Block copolymers were synthesized from two kinds of phenylacetylenes by using the present cationic rhodium catalyst. Well-defined palladium catalysts were developed, which enabled the synthesis of end-functionalized poly(phenylacetylene)s. The produced poly (phenyacetylene) has a hydroxymethylphenyl end group and thus can be applied as a macroinitiator to the synthesis of a block copolymer composed of poly(phenylacetylene) and poly(β-propiolactone) blocks. [ABSTRACT FROM AUTHOR]

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