STEREOREGULAR POLYMERIZATION OF PHENYLACETYLENES CATALYZED BY [HYDRIDOTRIS(PYRAZOLYL)BORATO]RHODIUM(I) COMPLEXES

Rhodium(I) tris(pyrazolyl)borate complexes Tp(R2)Rh(cod) (R = Me, Ph, i-Pr) were found to serve as efficient catalysts for highly stereoregu lar polymerization of phenylacetylene derivatives (p-YC6H4C drop CH; Y double bond H, Me, Cl, CN, CO2Me, COMe, NO2) to give poly(phenylacety lene) species having a head-to-tail, cis-transoidal structure. The cat alytic activity was strongly affected by the substituents (R) at the 3 - and 5-positions of the pyrazolyl groups, and the more sterically dem anding R groups led to higher catalytic activity.