The invention relates to a metallocene complex according to formula (1) wherein M is a metal selected from lanthanides or transition metals from group 3, 4, 5 or 6 of the Periodic System of the Elements, Q is an anionic ligand to M, k is the number of Q groups and equals the valence of M minus 2, Z1, Z2, Z3 and Z4 are identical or different and can be chosen from the group consisting of hydrogen and a hydrocarbon radical with 1-20 carbon atoms, and adjacent substituents Z can form a ring system together with the carbon atoms of the Cp ring to which they are bound.