Organometallic transition metal compound, biscyclopentadienyl ligand system, catalyst system and preparation of polyolefins

A biscyclopentadienyl ligand system of the formula (II):

• or its double bond isomers,
• wherein
• Z is a divalent organic group which has from 1 to 40 carbon atoms and together with the two carbon atoms of the indenyl system forms a saturated or unsaturated, substituted or unsubstituted ring system having a ring size of from 4 to 12 atoms, where Z within the ring system fused to the indenyl system optionally contains at least one heteroatom, identical or different, selected from the group consisting of Si, Ge, N, P, O, S, Se and Te;
• R1 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R2 is hydrogen;
• R1 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R4 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R5 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R6 is hydrogen;
• R7, R8 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms or R7 and R8 together with the atoms connecting them form a monocyclic or polycyclic, substituted or unsubstituted ring system which has from 1 to 40 carbon atoms and optionally contains heteroatoms selected from the group consisting of the elements Si, Gel, N, P, O, S, Se and Te;
• A is a bridge consisting of a divalent atom or a divalent group;
• and wherein if R3 is hydrogen, then R5 is an organic radical which has from 3 to 20 carbon atoms and is branched in the α position.

A catalyst system for the polymerization of olefins, which comprises at least one organometallic transition metal compound of the formula (I):

• where
• M1 is an element of group 3, 4, 5 or 6 of the Periodic Table of the Elements or the lanthanides,
• the radicals X are identical or different and are each an organic or inorganic radical, with two radicals X also being able to be joined to one another;
• n is a natural number from 1 to 4;
• Z is a divalent organic group which has from 1 to 40 carbon atoms and together with the two carbon atoms of the indenyl system forms a saturated or unsaturated, substituted or unsubstituted ring system having a ring size of from 4 to 12 atoms, where Z within the ring system fused to the indenyl system optionally contains at least one heteroatom, identical or different, selected from the group consisting of Si, Ge, N, P, O, S, Se and Te;
• R1 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R1 is hydrogen;
• R3 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R4 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R5 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R6 is hydrogen;
• R7, R8 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms or R7 and R8 together with the atoms connecting them form a monocyclic or polycyclic, substituted or unsubstituted ring system which has from 1 to 40 carbon atoms and optionally contains heteroatoms selected from the group consisting of the elements Si, Ge, N, P, O, S, Se and Te;
• A is a bridge consisting of a divalent atom or a divalent group;
• and wherein
• if R3 is hydrogen, then R5 is an organic radical which has from 3 to 20 carbon atoms and is branched in the α position;
• and at least one cocatalyst which converts the at least one organometallic transition metal compound into a species which is polymerization-active toward at least one olefin.

A process comprising polymerizing or copolymerizing at least one olefin in the presence of a catalyst system comprising an organometallic transition metal compound of the formula (I):

• where
• M1 is an element of group 3, 4, 5 or 6 of the Periodic Table of the Elements or the lanthanides,
• the radicals X are identical or different and are each an organic or inorganic radical, with two radicals X also being able to be joined to one another;
• n is a natural number from 1 to 4;
• Z is a divalent organic group which has from 1 to 40 carbon atoms and together with the two carbon atoms of the indenyl system forms a saturated or unsaturated, substituted or unsubstituted ring system having a ring size of from 4 to 12 atoms, where Z within the ring system fused to the indenyl system optionally contains at least one heteroatom, identical or different, selected from the group consisting of Si, Ge, N, P, O, S, Se and Te;
• R1 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R2 is hydrogen;
• R3 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R4 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R5 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R6 is hydrogen;
• R7, R8 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms or R7 and R8 together with the atoms connecting them form a monocyclic or polycyclic, substituted or unsubstituted ring system which has from 1 to 40 carbon atoms and optionally contains heteroatoms selected from the group consisting of the elements Si, Ge, N, P, O, S, Se and Te;
• A is a bridge consisting of a divalent atom or a divalent group;
• and wherein if R3 is hydrogen, then R5 is an organic radical which has from 3 to 20 carbon atoms and is branched in the α position;
• and at least one cocatalyst which converts the at least one organometallic transition metal compound into a species which is polymerization-active toward at least one olefin.

A process for preparing an organometallic transition metal compound, which comprises reacting a biscyclopentadienyl ligand system of the formula (II):

• or its double bond isomers,
• wherein
• Z is a divalent organic group which has from 1 to 40 carbon atoms and together with the two carbon atoms of the indenyl system forms a saturated or unsaturated, substituted or unsubstituted ring system having a ring size of from 4 to 12 atoms, where Z within the ring system fused to the indenyl system optionally contains at least one heteroatom, identical or different, selected from the group consisting of Si, Ge, N, P, O, S, Se and Te;
• R1 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R2 is hydrogen;
• R3 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R4 is hydrogen, halogen or an organic radical having from 1 to 40 carbon atoms;
• R5 is hydrogen or an organic radical having from 1 to 40 carbon atoms;
• R6 is hydrogen;
• R7, R8 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms or R7 and R8 together with the atoms connecting them form a monocyclic or polycyclic, substituted or unsubstituted ring system which has from 1 to 40 carbon atoms and optionally contains heteroatoms selected from the group consisting of the elements Si, Ge, N, P, O, S, Se and Te;
• A is a bridge consisting of a divalent atom or a divalent group,
• or a bisanion prepared therefrom with a transition metal compound.