Polymerization of phenylacetylene by cationic acetylacetonate palladium complexes

A series of cationic acetylacetonate palladium complexes were demonstrated to be active for the polymerization and oligomerization of phenylacetylene. Catalyst screening and optimization have determined the superior activity of complex [(acac)Pd(TOMPP)(2)]BF4 (TOMPP - tris(2-methoxyphenyl)phosphine) for the stereospecific polymerization of phenylacetylene in non-coordinating solvents as well as in an aqueous emulsion. Catalyst turnover frequencies of 100-160 h(-1) were observed (M-w = (10-27).10(4) with PDI = 1.7-2.3, cis double bond content in PPA up to 95%). The effect of temperature, solvent nature, and the use of cocatalyst, BF3 center dot OEt2, have been studied.