Patent ID: 7358381

Claim:
A process for preparing racemic metallocene complexes of the formula (I) is a divalent group is a divalent group and the substituents and indices have the following meanings: M is titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 9 , R 10 , R 11 , R 1′ , R 2′ , R 3′ , R 4′ , R 5′ , R 6′ , R 9′ , R 10′ and R 11′ are identical or different and are each hydrogen, halogen, C 1 -C 20 -alkyl, 3- to 8-membered cycloalkyl which optionally bears a C 1 -C 10 -alkyl group as substituent, C 6 -C 15 -aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl part, arylalkyl having from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl part, —OR 13 , —SR 13 , —N(R 13 ) 2 , —P(R 13 ) 2 , or Si(R 13 ) 3 , where R 13 are identical or different and are each C 1 -C 10 -alkyl, C 6 -C 15 -aryl, C 3 -C 10 -cycloalkyl, alkylaryl, where the radicals mentioned may be partially or fully substituted by heteroatoms, R 8 , R 12 , R 8′ and R 12′ are identical or different and are each C 1 -C 10 -alkyl, Y is oxygen R 7 is a -[Z(R 15 )(R 16 )] m — group, where Z are identical or different and are each silicon, germanium, tin or carbon, R 15 and R 16 are each hydrogen, C 1 -C 10 -alkyl, C 3 -C 10 -cycloalkyl or C 6 -C 15 -aryl, m is 1, 2, 3 or 4, which comprises reacting a transition metal complex of the formula (II) where X are identical or different and are each hydrogen, halogen, C 1 -C 10 -alkyl, C 6 -C 15 -aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl part, —OR 17 or —NR 17 2 , where R 17 are identical or different and are each C 1 -C 10 -alkyl, C 6 -C 15 -aryl, C 3 -C 10 -cycloalkyl, alkylaryl, n is an integer from 1 to 4 and corresponds to the valence of M minus 2, with cyclopentadienyl derivatives of the formula (III) where M 2 is an alkali metal ion or alkaline earth metal ion, and p is 1 when M 2 is an alkaline earth metal ion and is 2 when M 2 is an alkali metal ion, and heating the resulting reaction mixture to a temperature in the range from −78 to +250° C.