Bis(pentafluorophenyl)(2-perfluorobiphenylyl)borane. A new perfluoroarylborane cocatalyst for single-site olefin polymerization

Bis(pentafluorophenyl)(2-perfluorobiphenylyl)borane, (C6F5)(2)B(C12F9) (BPB ), has been synthesized and characterized to serve as a new strong organo-l ewis acid cocatalyst for single-site olefin polymerization. BPB efficiently activates a variety of group 4 dimethyl complexes to form highly active ho mogeneous Ziegler-Natta olefin polymerization catalysts. Reaction of BPB wi th Cp2ZrMe2, rac-Me2Si(Ind)(2)ZrMe2, and (CGC)MMe2 (M = Zr, Ti; CGC = Me2Si (eta(5)-Me4C5)((BuN)-Bu-t)) (1:1 molar ratio) rapidly and cleanly produces the base-free cationic complexes Cp2ZrMe+ [MeB(C12F9)(C6F5)(2)](-) (1), rac -Me2Si(Ind)(2)ZrMe+ [MeB(C12F9)(C6F5)(2)](-) (2), and (CGC)MMe+[MeB(C12F9)( C6F5)(2)](-) (M = Zr, 3; M = Ti, 4), respectively. These complexes have bee n characterized by NMR and elemental analysis and are shown to be competent for ethylene and propylene polymerization. In general, BPB-derived catalys ts exhibit polymerization activities comparable to or higher than those of the B(C6F5)(3)-derived analogues, with the products exhibiting higher molec ular weights but comparable polydispersities, polypropylene isotacticities, and, for ethylene + 1-hexene, comonomer incorporation.