SYNTHESES AND MODELS FOR STEREOSPECIFIC METALLOCENES

Stereospecific, bridged [LL']M(R)+ catalysts (L,L' = substituted-cp, ind, or flu; R = hydrocarbyl) have been prepared by three new synthetic procedures. Propylene polymerizations with our new catalyst synthetic reagents, tris(pentafluorophenyl)boron (F15), magnesium dichloride, and trityl tetrakis(pentafluorophenyl) borate (trityl-F20) are compared with results obtained with the N,N-dimethyl-anilinium-F20 salt and with methylaluminoxane (MAO). Trimethylaluminium(TMA) or triethylaluminium(TEAL) scavenged poisons in the MAO free polymerizations. The site-control mechanism is discussed.