New mononuclear and polynuclear perfluoroarylmetalate cocatalysts for stereospecific olefin polymerization

Mononuclear and polynuclear perfluoroarylborate, -aluminate, and -gallate cocatalysts for metallocene-mediated olefin polymerization have been synthesized as trityl fluoride adducts of known perfluoroaryl-metalloid cocatalysts. Propylene polymerization experiments using these species as cocatalysts with the C-s-symmetric precatalyst [Me2C(Cp)(fluorenyl)]ZrMe2 reveal a marked counteranion dependence of polymerization activity, product polymer syndiotacticity, and relative [m] and [mm] stereoerror abundance, with the polynuclear perfluoroaryl cocatalysts uniformly giving enhanced product polymer stereoregularity us the neutral analogues.