| abstract |
A very active catalyst system for olefin polymerization comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I <IMAGE> (I) in which, preferably, M1 is Zr or Hf, R1 and R2 are alkyl or halogen, R3 is hydrogen, R4 to R6 and alkyl or aryl, -(CR8R9)m-R7 -(CR8R9)n is a single- or multi-membered chain, in which R' can also be a (substituted) hetero atom, and m+n is zero or 1. |