Patent ID: 7619090

Claim:
A monocyclopentadienyl complex which is suitable for olefin polymerization and which comprises the following structural feature of the formula (HCp)Y n M, where the variables have the following meanings: HCp is a cyclopentadienyl system containing at least one fused heretocycle, Y is a substitutent which is bound to HCp and comprises at least one uncharged donor containing an atom of group 14 or 15 of the Periodic Table and has the formula -Z m -A, where the variables have the following meanings: Z is a divalent bridge between A and HCp, A is where R 1C -R 10C are each, independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 6 -C 20 -aryl alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR 11C 3 , where the organic radical R 1C -R 10C may also be substituted by halogens and two vicinals radicals R 1C -R 10C may also be joined to form a five- or six-membered ring and R 11C are each independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 6 -C 20 -aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R 11C may also be joined to form a five- or six-membered ring, m is 1, or may also be 0, M is a metal of group 3, 4, 5, or 6 of the Periodic Table, and n is 1, wherein HCp and Y form a ligand (HCp-Y) of the formula II where the variables have the following meanings: E 1A -E 5A are each carbon or at most one E 1A to E 5A is phosphorus or nitrogen, R 1A -R 4A are each, independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 6 -C 20 -aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, SiR 6A 3 , where the organic radicals R 1A -R 4A may also be substituted by halogens and two vicinal radicals R 1A -R 4A may also be joined to form a five- or six-membered ring, with the proviso that at least two vicinal radicals R 1A -R 4A are joined to form a heterocycle which contains at least one atoms from group 15 or 16 of the Periodic Table.