Patent ID: 7109278

Claim:
An organometallic transition metal compound of the formula (I) where M 1 is an element of group 3, 4, 5 or 6 of the Periodic Table of the Elements or the lanthanides, X are identical or different or different and are each halogen, hydrogen, C 1 –C 20 -alkyl, C 2 –C 20 -alkenyl, C 6 –C 22 -aryl, alkylaryl or arylalkyl having from 1 to 10 carbon atoms in the alkyl part and from 6 to 22 carbon atoms in the aryl part, —OR 5 or —NR 5 R 6 , where two radicals X may also be joined to one another or two radicals X may together form a substituted or unsubstituted diene ligand, in particular a 1,3-diene ligand, where R 5 and R 6 are each C 1 –C 10 -alkyl, C 6 –C 15 -aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 22 carbon atoms in the aryl radical, n is a natural number from 1 to 4 which is equal to the oxidation number of M 1 minus 2, R 1 is a C 2 –C 40 radical which is branched in the α position R 2 is hydrogen or a C 1 –C 40 radical which is unbranched in the α position, R 3 , R 3a and R 3b are identical or different and are each hydrogen or a C 1 –C 40 radical, where R 3 is not hydrogen, R 4 is a substituted or unsubstituted C 6 –C 40 -aryl radical or C 2 –C 40 -heteroaromatic radical containing at least one heteroatom selected from the group consisting of O, N, S and P, T is a divalent C 1 –C 40 group which together with the cyclopentadienyl ring forms a further saturated or unsaturated ring system having a ring size of from 5 to 12 atoms, where T may contain the heteroatoms Si, Ge, N, P, O or S within the ring system fused onto the cyclopentadienyl ring, and Z is a bridge consisting of a divalent atom or a divalent group.