Patent ID: 7193099

Claim:
A process for preparing racemic metallocene complexes by reacting transition metal complexes of the formula (I) where the substituents and indices have the following meanings: M is titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten or an element of transition group III of the Periodic Table and the lanthanides, X are identical or different and are each fluorine, chlorine, bromine, iodine, hydrogen, 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 9 or —NR 9 2 , where R 9 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, R 1 , R 2 , R 4 , R 5 , R 7 , R 8 are identical or different and are each hydrogen, fluorine, chlorine, bromine, iodine, C 1 –C 20 -alkyl, 3- to 8-membered cycloalkyl which may in turn bear 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 10 , —SR 10 , —N(R 10 ) 2 , —P(R 10 ) 2 or Si(R 10 ) 3 , where R 10 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 3 , R 6 are identical or different and are each hydrogen, —OR 11 , —SR 11 , —N(R 11 ) 2 , —P(R 11 ) 2 or Si(R 11 ) 3 , where R 11 are identical or different and are each C 1 –C 10 -alkyl, C 3 –C 10 -cycloalkyl, Y are identical or different and are each where R 12 are identical or different and are each hydrogen, halogen, C 1 –C 10 -alkyl, C 1 –C 10 -fluoroalkyl, C 6 –C 10 -fluoroaryl, C 6 –C 10 -aryl, C 1 –C 10 -alkoxy, C 2 –C 10 -alkenyl, C 7 –C 40 -arylalkyl, C 8 –C 40 -arylalkenyl, C 7 –C 40 -alkylaryl, or two radicals R 12 together with the atoms connecting them form a ring, M 1 is silicon, germanium or tin, with cyclopentadienyl derivatives of alkali metals or alkaline earth metals and heating the reaction mixture obtained in this way to a temperature in the range from −78 to 250° C.