| abstract |
The invention pertains to metallocenes of formula (I), wherein M is a metal group of the group of Ti, Zr, Hf, V, Nb and Ta or an element from the group of lanthanides; X 1 and X 2 stand for an alkyl, alkoxy, aryl, aryloxy, alkenyl, arylalkyl, alkylaryl or arylalkenyl group, hydrogen or halogen; L 1 and L 2 stand for a hydrocarbon which can form a sandwich structure with M; R stands for C, Si, Ge or Sn; and A and B stand for a trimethylsilyl radical, B optionally for an alkyl or aryl radical. ##STR1## |