Patent ID: 7635783

Claim:
A process for meso-selective preparation of ansa-metallocene complexes of formula (I): which comprises reacting a ligand starting compound of formula (II): with a transition metal compound of formula (III): (LB) y M 1 (OR 3 )X x+1 (III) where R 1 , R 1′ are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms; R 2 , R 2′ are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms; R 3 is a bulky organic radical comprising at least 3 carbon atoms, and is bound to the oxygen atom via a nonaromatic carbon or silicon atom, and may be substituted by halogen atoms or further organic radicals comprising from 1 to 20 carbon atoms, and optionally comprise at least one heteroatom selected from the group consisting of Si, N, P, O and S; T, T′ are identical or different and are each a divalent organic group comprising from 1 to 40 carbon atoms, and together with the cyclopentadienyl rings form at least one further saturated or unsaturated, substituted or unsubstituted ring system comprising from 5 to 12 atoms, where T and T′ optionally comprises at least one heteroatom selected from Si, Ge, N, P, As, Sb, O, S, Se or Te; A is a bridge consisting of a divalent atom or a divalent group; M 1 is at least one lanthanide or an element of group 3, 4, 5 or 6 of the Periodic Table of Elements; X are identical or different and are each an organic or inorganic radical which is able to be replaced by a cyclopentadienyl anion; x is a natural number from 1 to 4; M 2 is an alkali metal, an alkaline earth metal, or a magnesium monohalide fragment; p is 1 when M 2 is a doubly positively charged metal ion, or 2 when M 2 is a singly positively charged metal ion or metal ion fragment; LB is an uncharged Lewis base ligand; and y is a natural number from 0 to 6.