Patent ID: 7074863

Claim:
A metallocene catalyst of formula (III) ( Lig ) p M ( X ) m ( A ) n (III) in which: M is a transition metal ion or a lanthanide metal ion; p is 1 or 2; m is greater than or equal to 0; n is greater than or equal to 0; n+m is equal to the valency of the metal not satisfied by ligand or ligands Lig; X is a ligand which co-ordinates to M selected from a Î· 5 hydrocarbyl, Î· 1 hydrocarbyl, halo, hydrocarbyl amino or hydrocarbyl amido ligand; A is a Ïƒ-ligand; and each Lig is independently a negatively charged indenyl or indenyloid moiety of the following formula (IV): wherein one or more of the ring carbon atoms may be replaced by a ring heteroatom; each Q is either a silicon or a germanium atom; either or both of the bonds shown as ----- may be present or absent; each R 1 which may be the same or different is a C 1-20 hydrocarbyl or a C 1-8 alkylamino at least one group (R 1 ) 3 QOâ€”being present on the 4,5,6 or 7 position; each R 2 is a hydrogen or a group bonded to the 5-membered ring through a carbon, oxygen, silicon, phosphorus, germanium, nitrogen or sulfur atom; each R 3 is a hydrogen or a group bonded to the 6-membered ring through a carbon, oxygen, silicon, germanium, nitrogen, phosphorus or sulfur atom; or two or more R 2 and/or two or more R 3 groups attached to adjacent ring atoms on the same ring together form a 5- to 8-membered fused ring; and optionally one R 2 or R 3 is â€”Lâ€”Z wherein L is a 1 to 4 atom chain and Z is a second moiety of formula (IV), a is an integer between 1 and 3, b is an integer between 1 and 3, the sum of a and b being no more than 4, c is an integer between 1 and 3, with the proviso that no more than one â€”Lâ€”Z group is present in each ligand.