Catalyst system and the use thereof

A catalyst system comprising

• a) at least one organometallic compound selected from the group consisting of metallocenes, diamine complexes of metals of transition groups III and IV of the Periodic Table of the Elements, diimine complexes of metals of transition group VIII of the Periodic Table of the Elements and 2,6-bis(imino)pyridyl complexes of metals of transition group VIII of the Periodic Table of the Elements,
• b) at least one Lewis base,
• c) at least one support and
• d) at least one organoelement compound which is the reaction product of at least one compound of the formula (VI) with at least one compound of the formula (IX),
• where
• R7 is a hydrogen atom or a boron-free C1-C40 group,
• R4 and R5 are identical or different and are each a hydrogen atom, a halogen atom or a C1-C40 group or R4 is an —OSiR3 group, where R are identical or different and are as defined for R5,
• X is an element of main group VI of the Periodic Table of the Elements or an NR group, where R is a hydrogen atom or a C1-C20-hydrocarbon radical,
• f is an integer from 0 to 3
• g is an integer from 0 to 3, where f+g is not equal to 0,
• h is an integer from 1 to 10,
• where the organoelement compound is covalently bound to the support,
• wherein the Lewis base is N,N-diethylbenzylamine, N,N-dimethyl-benzylamine, N-benzyldimethylamine, N-benzyldiethylamine, N-benzylbutylamine, N-benzyl-tert-butylamine, N-benzylisopropylamine, N-benzylmethylamine, N-benzylethylamine, N-benzyl-1-phenylethylamine, N-benzyl-2-phenylethylamine, N,N-dimethylbenzylamine, N,N-diethylbenzylamine, N-methyl-N-ethylbenzylamine, N-methyldibenzylamine or N-ethyldi(benzyl)amine.