Catalysts based on fulvene metal complexes

A process for producing a fulvene metal complex containing catalyst system comprising the step of thermally treating in a suitable reaction medium, a mixture of an aluminoxane- and boron-free Lewis acid suitable for activation and a metal complex of formula (II)

• wherein
• M is a metal cation from the group IIIb, IVb, Vb, VIb or of the lanthanides or of the actinides of the Periodic Table of the Elements [N. N. Greenwood, A. Earnshaw, Chemie der Elements, VCH 1990],
• A signifies an optionally uni- or multi-bridged anionic ligand, R1, R2, R3, R4, R5, R6, and R7 are identical or different and stand for hydrogen, halogen, a cyano group, a C1 to C20 alkyl group, a C1 to C10 fluoroalkyl group, a C6 to C10 fluoroaryl group, a C1 to C10 alkoxy group, a C6 to C20 ayryl group, a C6 to C10 aryloxy group, a C2 to C10 alkenyl group, a C7 to C40 arylalkyl group, a C7 to C40 alkylaryl group, a C8 to C40 arylalkenyl group, a C2 to C10 alkinyl group, an optionally substituted silyl group or form respectively together with the atoms linking them one or more ring systems, which can contain one or more hetero atoms,
• X stands for hydrogen, halogen, a C1 to C30 alkyl group, a C6 to C10 aryl group, a C2 to C10 alkenyl group, a C7 to C40 arylalkyl group, a C7 to C40 alkylaryl group, a C8 to C40 arylalkenyl group, a C2 to C10 alkinyl group, and an optionally silyl group.