Process for preparing a carbon-bridged biscyclopentadiene compound

The present invention relates to a process for preparing a carbon-bridged biscyclopentadiene compound by reacting one or two cyclopentadiene compounds LH with a carbonyl compound in the presence of at least one base and at least one phase transfer catalyst.

The present invention relates to a process for preparing a carbon-bridged 
biscyclopentadiene compound and the use of this process as a substep in 
the preparation of a carbon-bridged biscyclopentadienyl metallocene which 
can be used as a catalyst component, e.g. for the preparation of 
polyolefins. 
It is known from the literature that polyolefins can be prepared in the 
presence of metallocenes in combination with aluminoxanes or other 
cocatalysts which, owing to their Lewis acidity, can convert the neutral 
metallocene into a cation and stabilize it. 
Melallocenes and semisandwich complexes are of great interest not only in 
respect of the polymerization or oligomerization of olefins, but they can 
also be used as hydrogenation, epoxidation, isomerization and C--C 
coupling catalysts (Chem. Rev. 1992, 92, 965-994). 
Carbon-bridged metallocenes are described in the literature (U.S. Pat. No. 
4,892,851; EP 416 566). the synthesis of these metallocenes proceeds via 
the preparation of the carton-bridged biscyclopentadiene ligand system 
which has to be carried out in a number of stages and proceeds only in a 
very small yields. 
EP 456 455 discloses the use of quaternary ammonium compounds in the 
alkylation of cyclopentadienes. 
Organometallics, 10, 1991, pages 3739-3745 discloses the use of 
triethylbenzylammonium chloride in the synthesis of biscyclopentadienyl 
dimethylmethane. 
It is known from the literature that cyclopentadiene can be reacted 
directly with cyclic ketones, with addition of a base, to give a bridged 
biscyclopentadiene ligand (J. Chem. Research (S), 1992, 162). This 
synthesis proceeds in low yield and subsequently requires a complicated 
chromatographic purification. 
It is therefore an object of the invention to provide a preparative process 
for carbon-bridged biscyclopentadiene compounds which avoids the 
disadvantages of the prior art. 
The present invention accordingly provides a process for preparing a 
carbon-bridged biscyclopentadiene compound by reacting one or two 
cyclopentadiene compounds LH, of which at least one cyclopentadiene 
compound is a substituted cyclopentadiene compound, with a carbonyl 
compound in the presence if at least one base and at least one phase 
transfer catalyst. 
The carbon-bridged biscyclopentadiene compound preferably has the formula I 
##STR1## 
where L are, independently of one another, identical or different 
cyclopentadiene groups, where at least one group L is a substituted 
cyclopentadienyl group, and R.sup.1 and R.sup.2 are identical or different 
and are each a hydrogen atom or a C.sub.1 -C.sub.30 -hydrocarbon radical. 
The cyclopentadiene groups L in formula I can be unsubstituted or 
substituted. They are identical or different, preferably identical. 
Examples of substituted cyclopentadiene groups L are: 
tetramethylcyclopendantadiene, 3-methylcyclopentadiene, 
3-tert-butylcyclopentadiene, methyl-tert-butylcyclopentadiene, 
isopropylcyclopentadiene, dimethylcyclopentadiene, 
trimethylcyclopentadiene, trimethylethylcyclopentadiene, 
3-phenylcyclopentadiene, diphenylcyclopentadiene, indene, 2-methylindene, 
2-ethylindene, 3-methylindene, 3-tert-butylindene, 3-trimethylsilylindene, 
2-methyl-4-phenylindene, 2-ethyl-4-phenylindene, 
2-methyl-4-naphthylindene, 2-methyl-4-isopropylindene, benzoindene, 
2-methyl-4,5-benzoindene, 2-methyl-.alpha.-acenaphthindene, 
2-methyl-4,6-diisopropylindene, fluorene, 2-methylfluorene or 
2,7-di-tert-butylfluorene. 
One or both of the cyclopentadiene groups L is a substituted 
cyclopentadiene group, in particular an indene derivative such as indene, 
2-methylindene, 2-ethylindene, 3-methylindene, 3-tert-butylindene, 
3-trimethylsilylindene, 2-methyl-4-phenylindene, 2-ethyl-4-phenylindene, 
2-methyl-4-naphthylindene, 2-methyl-4-isopropylindene, benzoindene, 
2-methyl-4,5-benzoindene, 2-methyl-.alpha.-acenanaphthindene, 
2-methyl-4,6-diisopropylindene or a fluorenyl derivative such as fluorene, 
2-methylfluorene or 2,7-di-tert-butylfluorene. 
The radical R.sup.1 and R.sup.2 are identical or different, preferably 
identical, and are C.sub.1 -C.sub.30 -hydrocarbon radicals such as C.sub.1 
-C.sub.10 -alkyl or C.sub.6 -C.sub.14 -aryl. The radicals R.sup.1 and 
R.sup.2 can also, together with the atoms connecting them, form a ring 
system which preferably contains from 4 to 40, particularly preferably 
from 5 to 15, carbon atoms. 
Examples of carbon-bridged biscyclopentadiene compounds of the formula I 
are: 
2,2-bisindenylpropane, 2,2-bisindenylbutane, 2,2-bisindenylmethane, 
2,2-bisindenylcyclopentane, 2,2-bisindenylcyclohexane, 1,1-bisindenyl- 
1-phenyl-ethane, 1,1-bisindenylethane, 1,1-bisindenylpropane, 
2,2-bis(2'-methyl-4'-phenylindenyl)propane, 
2,2-bis(2'-ethyl-4'-phenyl-indenyl)propane, 
2,2-bis(2'-methyl-4'-naphthylindenyl)propane, 
2,2-bis(2'-methyl-4',5'-benzoindenyl)propane, 
1,1-bis(2'-methyl-4'-phenylindenyl)-1-phenylethane, 
1,1-bis(2'-ethyl-4'-phenyl-indenyl)-1-phenylethane, 
1,1-bis(2'-methyl-4'-naphthylindenyl)-1-phenylethane, 
2,2-biscyclopentadienylbutane, 2,2-bis(methyl-cyclopentadienyl)propane, 
2-cyclopentadienyl-2-fluorenylpropane, 
2-(3'-methylcyclopentadienyl)-2-fluorenylpropane, 
2-indenyl-2-indenyl-2-fluorenylpropane, 
2-cyclopentadienyl-2-indenylpropane, 
1-cyclo-pentadienyl-1-fluorenyl-1-phenylethane, 
1-indenyl-1-fluorenyl-1-phenylethane, 
2-(3'-tert-butylcyclopentadienyl)-2-fluorenylpropane, 
1-cyclopentadienyl-1-indenyl-1-phenylethane. 
To prepare biscyclopentadiene compounds of the formula I, in which the two 
cyclopentadiene groups L are identical, use is made of one cyclopentadiene 
compound LH. To prepare biscyclopentadiene compounds of the formula I, in 
which the two cyclopentadiene groups L are different, two different 
cyclopentadiene compounds LH are used. 
The cyclopentadiene compounds LH used in the process of the invention can 
be substituted or unsubstituted, with at least one cyclopentadiene 
compound being a substituted cyclopentadiene compound. 
Examples of substituted cyclopentadiene compounds LH are 
tetramethylcyclopentadiene, methylcyclopentadiene, 
tert-butylcyclopenta-diene, methyl-tert-butylcyclopentadiene, 
isopropylcyclopentadiene, dimethylcyclopentadiene, 
trimethylcyclopentadiene, trimethylethylcyclo-pentadiene, 
phenylcyclopentadiene, diphenylcyclopentadiene, indene, 2-methylindene, 
2-ethylindene, 3-methylindene, 3-tert-butylindene, 3-trimethylsilylindene, 
2-methyl-4-phenylindene, 2-ethyl-4-phenylindene, 
2-methyl-4-naphthylindene, 2-methyl-4-isopropylindene, benzoindnene, 
2-methyl-4,5-benzoindene, 2-methyl-.alpha.-acenaphthindene, 
2-methyl-4,6-diisopropylindene, fluorene, 2-methylfluorene or 
2,7-di-tert-butylfluorene. 
One or both of the cyclopentadiene compounds LH used in the process of the 
invention is a substituted cyclopentadiene compound, in particular an 
indene derivative such as indene, 2-methylindene, 2-ethylindene, 
3-methylindene, 3-tert-butylindene, 3-trimethylsilylindene, 
2-methyl-4-phenylindene, 2-ethyl-4-phenylindene, 
2-methyl-4-naphthylindene, 2-methyl-4-isopropylindene, benzoindene, 
2-methyl-4,5-benzoindene, 2-methyl-.alpha.-acenanaphthindene, 
2-methyl-4,6-diisopropylindene or a fluorenyl derivative such as fluorene, 
2-methylfluorene or 2,7-di-tert-butylfluorene. 
The carbonyl compounds used in the process of the invention are preferably 
ketones such as acetone, acetophenone, benzophenone, cyclo-hexanone, 
cyclopentanone, 2-hexanone, 2-butanone, 2-methyl-3-pentanone or 
2,2-dimethyl-3-butanone or aldehydes such as acetaldehyde or benzaldehyde. 
Bases which can be used are hydroxides of group Ia, IIa or IIIa of the 
Periodic Table of the Elements, for example LiOH, NaOH, KOH, RbOH, 
Mg(OH).sub.2, Ca(OH).sub.2 and Sr(OH).sub.2. Preference is given to using 
one base, e.g. LiOH, NaOH or KOH. 
Phase transfer catalysts which can be used are quaternary ammonium salts 
and phosphonium salts of the formula R.sup.3.sub.4 Z!.sup.+ X.sup.-, 
where R.sup.3 are identical or different and are each a hydrogen atom, a 
halogen atom or a C.sub.1 -C.sub.40 -group such as a C.sub.1 -C.sub.20 
-alkyl group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.6 -C.sub.20 -aryl 
group, a C.sub.2 -C.sub.12 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl 
group, a C.sub.7 -C.sub.40 -alkylaryl group, or a C.sub.8 -C.sub.40 
-arylalkenyl group, which can each bear radicals such as --NR.sup.4.sub.3, 
--SR.sup.4.sub.2, --SiR.sup.4.sub.3 or --OSiR.sup.4.sub.3, where R.sup.4 
are identical or different and are each a halogen atom, a C.sub.1 
-C.sub.10 -alkyl group or a C.sub.6 -C.sub.10 -aryl group, or two or more 
radicals R.sup.3 together with the atoms connecting them can form a ring 
system which preferably contains from 4 to 40, particularly preferably 
from 5to 15, carbon atoms, Z is nitrogen or phosphorus and X.sup.- is a 
halide, hydroxide, tetrahaloborate, (e.g. tetrafluoroborate), 
hydrogensulfate, sulfate or hexahalophosphate, (e.g. hexafluorophosphate). 
Examples of compounds suitable as phase transfer catalysts are: 
benzyltrimethylammonium chloride, 
benzyltrimethylammonium hydroxide (in particular as an aqueous 40% strength 
solution), 
hexadecyltrimethylammonium bromide, 
hexadecyltrimethylammonium chloride (in particular as an aqueous 50% 
strength solution), 
ethylhexadecyldimethylammonium bromixe, 
tetraethylammonium tetrafluoroborate, 
tetraethylammonium bromide, 
tetraethylammonium hydroxide (in particular as an aqueous 20% strength 
solution), 
benzyltriethylammonium chloride, 
benzyltriethylammonium hydroxide, 
tetrapropylammonium bromide, 
tetrabutylammonium chloride, 
tetrabutylammonium fluoridetrihydrate, 
tetrabutylammonium tetrafluoroborate, 
tetrabutylammonium hydrogensulfate, 
tetrabutylammonium hydroxide (in particular as a 12.5% strength solution in 
methanol), 
benzeltributylammonium bromide, 
tetraoctylammonium bromide, 
methyltrioctylammonium chloride, 
tetrabutylphosphonium bromide, 
tetrabutylphosphonium chloride, 
tributylhexadecylphosphonium bromide, 
ethyltrioctylphosphonium bromide, 
butyltriphenylphosphonium chloride and tetraphenylphosphonium bromide. 
Further phase transfer catalysts which can be used are crown compounds, in 
particular those of the formulae II, III and IV 
##STR2## 
where D is S, O, NR.sup.5,k PR.sup.5 and R.sup.5 are identical or 
different and are each a hydrogen atom, a halogen atom, a C.sub.1 
-C.sub.40 -group such as a C.sub.1 -C.sub.20 -alkyl group, a C.sub.1 
-C.sub.10 -alkoxy group, a C.sub.6 -C.sub.20 -aryl group, a C.sub.2 
-C.sub.12 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.7 
-C.sub.40 -alkylaryl group or a C.sub.8 -C.sub.40 -arylalkenyl group, 
which can each bear radicals --NR.sup.6.sub.3, --SR.sup.6.sub.2, 
--SiR.sup.6.sub.3 or --OSiR.sup.6.sub.3 where R.sup.6 are identical or 
different and are each a halogen atom, a C.sub.1 -C.sub.10 -alkyl group or 
a C.sub.6 -C.sub.10 -aryl group, W are identical or different moieties 
R.sup.7.sub.2 C!.sub.n, where R.sup.7 are identical or different and are 
each a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.40 -group such as a 
C.sub.1 -C.sub.20 -alkyl group, a C.sub.1 -C.sub.10 -alkoxy group, a 
C.sub.6 -C.sub.20 -aryl group, a C.sub.2 -C.sub.12 -alkenyl group, a 
C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.7 -C.sub.40 -alkylaryl group, 
or a C.sub.8 -C.sub.40 -arylalkenyl group, which can each bear radicals 
--NR.sup.8.sub.3, --SR.sup.8.sub.2, --SiR.sup.8.sub.3 or 
--OSiR.sup.8.sub.3, where R.sup.8 is a halogen atom, a C.sub.1 -C.sub.10 
-alkyl group or a C.sub.6 -C.sub.10 -aryl group, or two or more radicals 
R.sup.7 together with the atoms connecting them can form a ring system 
which preferably contains from 4 to 40, particularly preferably from 5 to 
15, atoms, in particular carbon atoms, n, 1 and m are identical or 
different and are each an integer from 1 to 40, preferably from 1 to 5, 
and are preferably identical, and B are identical or different and are 
NR.sup.9 or PR.sup.9, where R.sup.9 is a hydrogen atom, a halogen atom or 
a C.sub.1 -C.sub.40 -group such as a C.sub.1 -C.sub.20 -alkyl group, a 
C.sub.1 -C.sub.10 -alkoxy group, a C.sub.6 -C.sub.20 -aryl group, a 
C.sub.2 -C.sub.12 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a 
C.sub.7 -CF.sub.40 -alkylaryl group, or a C.sub.8 -C.sub.40 -arylalkenyl 
group, which can bear radicals --NR.sup.10.sub.3, --SR.sup.10.sub.2, 
--SiR.sup.10.sub.3, --OSiR.sup.10.sub.3, where R.sup.10 is a halogen atom, 
a C.sub.1 -C.sub.10 -alkyl group or a C.sub.6 -C.sub.10 -aryl group. 
Examples of crown compounds are: 
12-crown-4, 15-crown-5, benzo-15-crown-5, 18-crown-6, decyl-18-crown-6, 
dibenzo-18-crown-6, dicyclohexyl-18-crown-8, dibenzo-24-crown-8, 
(+)-18-crown-6-tetracarboxylic acid, N-phenylaza-15-crown-5, 
.RTM.Kryptofix 21, .RTM.Kryptofix 22, .RTM.Kryptofix 22 DD, .RTM.Kryptofix 
23, tris2-(-methoxethoxy)-ethyl!amine, .RTM.Kryptofix 5, .RTM.Kryptofix 
111, .RTM.Kryptofix 211, .RTM.Kryptofix 221, .RTM.Kryptofix 221 D, 
.RTM.Kryptofix 222, .RTM.Kryptofix 222 B (50% strength solution in 
toluene), .RTM.Kryptofix 222 BB, .RTM.Kryptofix 222 CC (50% strength 
solution in toluene), .RTM.Kryptofix 222 D (50% strength solution in 
toluene), .RTM.Kryptofix 221 B (polymer), and .RTM.Kryptofix 222 B 
(polymer). 
In the process of the invention, preference is given to using a phase 
transfer catalyst. The concentration of the phase transfer catalyst can be 
from 0.1 to 100 mol % based on the amount of cyclopentadiene compound(s) 
LH used, particularly preferably from 1 to 20 mol %. 
The process of the invention is carried out in a single-phase or multiphase 
system in the presence of at least one base and at least one phase 
transfer catalyst. The process of the invention is preferably carried out 
in a multiphase system, in particular in a two-phase system where one 
phase is an organic solvent, e.g. an aromatic solvent such as toluene, 
xylene or an aliphatic solvent such as tetrahydrofuran, hexane or 
dichloromethane, and the second phase is water. Particular preference is 
given to the two-phase systems toluene/water, dichloromethane/water and 
tetrahydrofuran/water. The concentration of base in the aqueous phase can 
be between 5 and 70% by weight, preferably from 25 to 60% by weight. 
To synthesize carbon-bridged biscyclopentadiene compounds containing two 
identical cyclopentadiene groups L, the cyclopentadiene compound LH can be 
used in excess (based on the carbonyl compound), preference is given to 
using from 2 to 3 equivalents of the cyclopentadiene compound LH, based on 
the carbonyl compound used (e.g. acetone or acetophenone). In the 
synthesis of carbon-bridged biscyclopentadiene compounds containing two 
different cyclopentadiene groups L, two different cyclopentadiene 
compounds LH are used. In this case, one of the two cyclopentadiene 
compounds is first reacted with the carbonyl compound, with the ratio of 
the two components being approximately 1:1. After a reaction time, which 
can be between 30 minutes and 100 hours, preferably between 30 minutes and 
20 hours, the second cyclopentadiene compound is added. 
The reaction temperature can be between 0.degree. C. and 100.degree. C., 
preferably from 0.degree. C. to 30.degree. C. The reaction times are 
generally between 30 minutes and 100 hours, preferably between 30 minutes 
and 20 hours. 
The volume ratio of organic phase/water (e.g. toluene/water, 
dichloromethane/water or tetrahydrofuran/water) can be between 10000:1 and 
1:50, preferably between 100:1 and 1:10, particularly preferably between 
10:1 and 1:. 
Preferably, a mixture of the cyclopentadiene compound LH and the carbonyl 
compound is initially charged in the organic solvent and the aqueous phase 
containing both the base and the phase transfer catalyst is added. It is 
also possible to carry out the reaction the other way around. Furthermore, 
the carbonyl compound can be added dropwise over a period of from 1 minute 
to 100 hours, preferably from 15 minutes to 4 hours, to the two-phase 
system (e.g. toluene/water, dichloromethane/water or 
tetrahydrofuran/water) containing the cyclopentadiene compound LH, the 
base and the phase transfer catalyst. 
The carbon-bridged biscyclopentadiene compounds obtainable using the 
process of the invention can be formed as double-bond isomers. 
The process of the invention is notable, in particular, for the fact that 
carbon-bridged biscyclopentadiene compounds can be obtained in a simple, 
single-stage synthesis in high yield. The substitution pattern of the 
bridge (R.sup.1 R.sup.2 C) and of the cyclopentadiene groups L can be 
varied within a wide range. 
The present invention also provides for the use of the process of the 
invention as a substep of a process for preparing a carbon-bridged 
biscyclopentadienyl metallocene, in particular a carbon-bridged 
biscyclopentadienyl metallocene of the formula V 
##STR3## 
where M.sup.1 is an element of group IIb, IVb, Vb or VIb of the Periodic 
Table of the Elements, in particular of group IVb. 
where L' are, independently of one another, identical or different 
cyclopentadienyl groups, where at least one cyclopentadiene group L' is a 
substituted cyclopentadiene group, R.sup.1 and R.sup.2 are identical or 
different and are each hydrogen or a C.sub.1 -C.sub.30 hydrocarbon radical 
such as C.sub.1 -C.sub.10 -alkyl or C.sub.6 -C.sub.14 -aryl, the radicals 
R.sup.1 and R.sup.2 together with the atoms connecting them form a ring 
system which preferably contains from 4 to 40, particularly preferably 
from 5 to 15, carbon atoms, and R.sup.11 and R.sup.12 are identical or 
different and are each hydrogen, a halogen atom or a C.sub.1 -C.sub.40 
-radical such as C.sub.1 -C.sub.10 -alkyl, C.sub.1 -C.sub.10 -alkoxy, 
C.sub.6 -C.sub.14 -aryl, C.sub.6 -C.sub.14 -aryloxy, C.sub.2 -C.sub.10 
-alkenyl, C.sub.7 -C.sub.40 -arylalkyl, C.sub.7 -C.sub.40 -alkylaryl, 
C.sub.8 -C.sub.40 -arylalkenyl, hydroxy, NR.sup.5, .sub.2 where R.sup.5 is 
C.sub.1 -C.sub.10 -alkyl, C.sub.1 -C.sub.10 -alkoxy, C.sub.6 -C.sub.14 
-aryl, C.sub.6 -C.sub.14 -aryloxy, C.sub.2 -C.sub.10 -alkenyl, C.sub.7 
-C.sub.40 -arylalkyl, C.sub.7 -C.sub.40 -alkylaryl or C.sub.8 -C.sub.40 
-arylalkenyl. 
The cyclopentadienyl groups L' in formula V can be unsubstituted or 
substituted. They are identical or different, preferably identical. 
Examples of substituted cyclopentadienyl groups L' are: 
tetramethylcyclopentadienyl, 3-methylcyclopentadienyl, 
3-tert-butylcyclopentadienyl, methyl-tert-butylcyclopentadienyl, 
isopropylcyclopentadienyl, dimethylcyclopentadienyl, 
trimethylcyclopentadienyl, trimethylethylcyclopentadienyl, 
3-phenylcyclopentadienyl, diphenylcyclopentadienyl, indenyl, 
2-methylindenyl, 2-ethylindenyl, 3-methylindenyl, 3-tert-butylindenyl, 
3-trimethylsilylindenyl, 2-methyl-4-phenylindenyl, 
2-ethyl-4-phenylindenyl, 2-methyl-4-naphthylindenyl, 
2-methyl-4-isopropylindenyl, benzoindenyl, 2-methyl-4,5-benzoindenyl, 
2-methyl-a-acenanaphthindenyl, 2-methyl-4,6-diisopropylindenyl, fluorenyl, 
2-methylfluorenyl or 2,7-di-tert-butylfluorenyl. 
One or both cyclopentadienyl groups L' is a substituted cyclopentadienyl 
group, in particular an indenyl derivative such as indenyl, 
2-methylindenyl, 2-ethylindenyl, 3-methylindenyl, 3-tert-butylindenyl, 
3-trimethylsilylindenyl, 2-methyl-4-phenylindenyl, 
2-ethyl-4-phenylindenyl, 2-methyl-4-naphthylindenyl, 
2-mthyl-4-isopropylindenyl, benzoindenyl, 2-methyl-4,5-benzoindenyl, 
2-methyl-.alpha.-acenanaphthindenyl, 2-methyl-4,6-diisopropylindenyl or a 
fluorenyl derivative such as fluorenyl, 2-methylfluorenyl or 
2,7-di-tert-butylfluorenyl. 
The radicals R.sup.1 and R.sup.2 are identical or different, preferably 
identical, and are C.sub.1 -C.sub.30 -hydrocarbon radicals such as C.sub.1 
-C.sub.10 -alkyl or C.sub.6 -C.sub.14 -aryl. The radicals R.sup.1 and 
R.sup.2 can also, together with the atoms connecting them, form a ring 
system which preferably contains from 4 to 40, particularly preferably 
from 5 to 15, carbon atoms. 
Preferably M.sup.1 is an element of group IV of the Periodic Table of the 
Elements, for example titanium, zirconium or hafnium, in particular 
zirconium, R.sup.1 and R.sup.2 are identical or different, preferably 
identical, and are hydrogen, C.sub.1 -C.sub.10 -alkyl or C.sub.6 -C.sub.14 
-aryl, in particular C.sub.1 -C.sub.5 -alkyl, and the radicals R.sup.11 
and R.sup.12 are preferably identical and are C.sub.1 -C.sub.4 -alkyl such 
as methyl or a halogen atom such as chlorine. 
Examples of carbon-bridged biscyclopentadienyl metallocenes obtainable by 
the metallocene preparation process of the invention are: 
isopropylinidenebis (2,3,4,5-tetramethylcyclopentadienyl)zirconium 
dichloride, 
methylnaphthylmethylenebis (2,3,4-trimethylcyclopentadienyl)zirconium 
dichloride, 
diphenylmethylenebis 
(2,3,4,5-tetramethylcyclopentadienyl)dimethyl-zirconium, 
methylenebis(1-indenyl)zirconium dichloride, 
isopropylidenebis(1-indenyl)zirconium dichloride, 
methylphenylmethylenebis(1-indenyl)zirconium dichloride, 
diphenylmethylenebis(1-indenyl)zirconium dichloride, 
methylenebis(1-(4-phenylindenyl))zirconium dichloride, 
isopropylidenebis(1-(4-phenylindenyl))zirconium dichloride, 
isopropylidenebis(1-(4-naphthylindenyl))zirconium chloride, 
methylphenylmethylenebis(1-(4-phenylindenyl))zirconium dichloride, 
diphenylmethylenebis(1-(4-phenylindenyl))zirconium dichloride, 
methylenebis(1-(4-isopropylindenyl))zirconium dichloride, 
isopropylidenebis(1-(4-isopropylindenyl))zirconium dichloride, 
methylphenylmethylenebis(1-(4-isopropylindenyl))dimethylzirconium, 
diphenylmethylenebis(1-(4-isopropylindenyl))hafnium dichloride, 
methylenebis(1-(4,5-benzoindenyl))zirconium dichloride, 
isopropylidenebis(1-(4,5-benzoindenyl)zirconium dichloride, 
methylphenylmethylenebis(1-(4,5-benzoindenyl))zirconium dichloride, 
diphenylmethylenebis(1-(4,5-benzoindenyl))zirconium dichloride, 
isopropylidene(1-indenyl)(cyclopentadienyl)zirconium dichloride, 
isopropylidene(1-indenyl)(3-methylcyclopentadienyl)zirconium dichloride, 
methylphenylmethylene(1-indenyl)(cyclopentadienyl)-zirconium dichloride, 
diphenylmethylene(1-indenyl)(cyclopentadienyl)zirconium dichloride, 
diphenylmethylene(1-(4-isopropyl)indenyl) (cyclopentadienyl)zirconium 
dichloride, 
isopropylidene(1-indenyl)(cyclopentadienyl)titanium dichloride, 
isopropylidene(1-indenyl)(3-methylcyclopentadienyl)-titanium dichloride, 
methylphenylmethylene(1-indenyl)(cyclopentadienyl)-titanium dichloride, 
diphenylmethylene(1-indenyl)(cyclopentadienyl)titanium dichloride, 
isopropylidene(1-indenyl)(9-fluorenyl)zirconium dichloride, 
isopropylidene(9-fluorenyl)(3-methylcyclopentadienyl)-zirconium dichloride, 
isopropylidene(9-fluorenyl)(3-tert-butylcyclopentadienyl)zirconium 
dichloride, 
methylphenylmethylene(9-fluorenyl)(cyclopentadienyl)-zirconium dichloride, 
diphenylmethylene(9-fluorenyl)(cyclopentadienyl)-zirconium dichloride, 
diphenylmethylene(9-fluorenyl)(3-phenylcyclopentadienyl)zirconium 
dichloride, 
diphenylmethylene(1-(4-isopropyl)indenyl)(9-fluorenyl)-zirconium 
dichloride, 
isopropylident(9-fluorenyl)(cyclopentadienyl)zirconium dichloride, 
methylphenylmethylene(9-fluorenyl)(cyclopentadienyl)-titanium dichloride, 
diphenylmethylene(9-fluorenyl)(cyclopentadienyl)-dimethyltitanium, 
diphenylmethylene(9-(2,7-di-tert-butyl)fluorenyl)(cyclopentadienyl)zirconiu 
m dichloride, 
isopropylidene (9-(2,7-di-tert-butyl)fluorenyl)-(cyclopentadienyl)zirconium 
dichloride. 
The present invention thus also provides a process for preparing a 
carbon-bridged biscyclopentadienyl metallocene, comprising the steps: 
a) Reacting one or two cyclopentadiene compounds LH, of which at least one 
cyclopentadiene compound is a substituted cyclopentadiene compound, with a 
carbonyl compound in the presence of at least one base and at least one 
phase transfer catalyst to give a carbon-bridged biscyclopentadiene 
compound, and 
b) Reacting the carbon-bridged biscyclopentadiene compound obtained in step 
a) with a metal compound M.sup.1 X.sub.p, where M.sup.1 is an element of 
group IIIb, IVb, Vb or VIb of the Periodic Table of the Elements, X is a 
C.sub.1 -C.sub.40 -radical such as C.sub.1 -C.sub.10 -alkyl or 
NR.sup.13.sub.2, where R.sup.13 is a C.sub.1 -C.sub.20 -hydrocarbon 
radical such as C.sub.1 -C.sub.10 -alkyl or C.sub.6 -C.sub.16 -aryl, a 
halogen or a pseudohalogen and p is an integer from 0 to 4, under 
conditions under which the carbon-bridged biscyclopentadiene compound 
obtained in step a) is complexed to give the carbon-bridged 
biscyclopentadienyl metallocene. 
The second step (b) of the preparative process for the carbon-bridged 
biscyclopentadienyl metallocene can be carried out by literature method 
(e.g. AU-A-31478/89; J. Organomet. Chem. 1988, 342, 21 or EP-A 284 707, 
which are hereby expressly incorporated by reference). The carbon-bridged 
biscyclopentadiene compound is preferably first reacted with a compound of 
the formula R.sup.14 M.sup.2 where M.sup.2 is a metal of group Ia, IIa or 
IIIa of the Periodic Table of the Elements and R.sup.14 is a C.sub.1 
-C.sub.20 -hydrocarbon radical such as C.sub.1 -C.sub.10 -alkyl or C.sub.6 
-C.sub.14 -aryl, and subsequently with the metal compound M.sup.1 X.sub.p. 
The reactions preferably take place in a suitable solvent, e.g. an 
aliphatic or aromatic solvent such as hexane or toluene, an ether solvent 
such as tetrahydrofuran or diethyl ether or in halogenated hydrocarbons 
such as methylene chloride or o-dichlorobenzene. In the metal compound of 
the formula M.sup.1 X.sub.p, M.sup.1 is preferably an element of group 
IIIb of the Periodic Table of the Elements, X is preferably a halogen atom 
or NR.sup.13.sub.2, where R.sup.13 is a C.sub.1 -C.sub.10 -hydrocarbon 
radical such as C.sub.1 -C.sub.10 -alkyl or C.sub.6 -C.sub.10 -aryl, and p 
is preferably 4. The carbon-bridged biscyclopentadienyl compound can be 
used as a mixture of isomers. 
Carbon-bridged biscyclopentadienyl metallocene halides of the formula V can 
be converted into the corresponding monoalkyl or dialkyl compounds by 
literature methods, e.g. by reaction with alkylating agents such as 
lithium alkyls, (J. Am. Chem. Soc. 1973, 95, 6263). 
The carbon-bridged biscyclopentadienyl metallocenes of the formula V can be 
formed as a mixture of the racemic form and the meso form. The separation 
of the isomeric forms, in particular the removal of the meso form, is 
known in principle (AU-A-31478/89; J. Organomet. Chem. 1988, 342, 21; EP-A 
284 707) and can be carried out by extraction or recrystallization using 
various solvents. 
The process of the invention allows the simple preparation of 
carbon-bridged biscyclopentadienyl metallocenes in high yield. 
The carbon-bridged biscyclopentadienyl metallocenes obtainable using the 
metallocene preparation process of the invention can, together with a 
cocatalyst, be used as highly active catalyst components, e.g. for the 
preparation of olefin polymers. 
It is possible to polymerize olefins, in particular those of the formula 
R.sup.a --CH.dbd.CH--R.sup.b, where R.sup.a and R.sup.b are identical or 
different and are each a hydrogen atom or a hydrocarbon radical having 
from 1 to 20 carbon atoms. R.sup.a and R.sup.b can also, together with the 
carbon atoms connecting them, form a ring. Examples of such olefins are 
ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 
1,3-butadiene, isoprene, norbornene, dimethanooctahydronaphthalene or 
norbornadiene. In particular, propylene and ethylene can be 
homopolymerized, ethylene can be copolymerized with a C.sub.3 -C.sub.20 
-olefin and/or a C.sub.4 -C.sub.20 -diene or ethylene can be copolymerized 
with a cycloolefin. 
The polymerization can be a homopolymerization or a copolymerization and 
can be carried out in solution, in suspension or in the gas phase, 
continuously or batchwise, in or more stages, at a temperature of from 
0.degree. to 200.degree. C., preferably from 30.degree. to 100.degree. C. 
In principle, a suitable cocatalyst in the polymerization is any compound 
which, owing to its Lewis acidity, can convert the neutral metallocene 
into a cation and stabilize the latter ("labile coordinatorion"). In 
addition, the cocatalyst or the anion formed therefrom should undergo no 
further reactions with the cation formed (EP 427 697). As cocatalyst, 
preference is given to using an aluminum compound and/or boron compound. 
Cocatalysts used are preferably aluminoxanes (EP-A 129-368, Polyhedron 
1990, 9, 429). In place of or in addition to an aluminoxane, it is 
possible to use boron compounds, in particular of the formulae R.sub.x 
NH.sub.4-x BR.sub.4 ', R.sub.x PH.sub.4-x BR.sub.4 ', R.sub.3 CBR.sub.4 ' 
or BR.sub.3 ', as cocatalysts. In these formulae, x is an integer from 1 
to 4, preferably 3, the radicals R are identical or different, preferably 
identical, and are C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.18 -aryl or 2 
radicals R together with the atoms connecting them form a ring, and the 
radicals R' are identical or different, preferably identical, and are 
C.sub.6 -C.sub.10 -alkyl or C.sub.6 -C.sub.18 -aryl which can be 
substituted by alkyl, haloalkyl or fluorine (EP-A 277 003, 277 004, 426 
638, 427697). 
It is possible to preactivate the metallocene with a cocatalyst, in 
particular an aluminoxane, prior to use in the polymerization reaction. 
This can significantly increase the polymerization activity. The 
preactivation of the metallocene is preferably carried out in solution. 
Here, the metallocene is preferably dissolved in a solution of the 
aluminoxane in an inert hydrocarbon. Suitable inert hydrocarbons are 
aliphatic or aromatic hydrocarbons. Preference is given to using toluene. 
To remove catalyst poisons present in the olefin, purification using an 
aluminum compound, preferably an aluminum alkyl such as trimethylaluminum 
or triethylaluminum, is advantageous. This purification can either be 
carried out in the polymerization system itself or the olefin is, prior to 
addition to the polymerization system, brought into contact with the 
aluminum compound and subsequently separated off again. 
As molecular weight regulator and/or to increase the catalyst activity, 
hydrogen can be added in the polymerization process. This enables low 
molecular weight polyolefins such as waxes to be obtained. 
The metallocene is preferably reacted with the cocatalyst outside the 
polymerization reactor in a separate step using a suitable solvent. 
Application to a support can be carried out during this step. 
In the process, a prepolymerization can be carried out by means of the 
metallocene. The prepolymerization is preferably carried out using the (or 
one of the) olefin(s) used in the polymerization. 
The catalyst used for the olefin polymerization can be supported. The 
application to a support allows, for example, the particle morphology of 
the polymer prepared to be controlled. The metallocene can be reacted 
first with the support and subsequently with the cocatalyst. The 
cocatalyst can also first be supported and subsequently reacted with the 
metallocene. It is also possible to support the reaction product of 
metallocene and cocatalyst. Suitable support materials are, for example, 
silica gels, aluminum oxides, solid aluminoxane or other inorganic support 
materials such as magnesium chloride. Another suitable support material is 
a polyolefin powder in finely divided form. The preparation of the 
supported cocatalyst can, for example, be carried out as described in EP 
567 952. 
Preferably, the cocatalyst, e.g. aluminoxane, is applied to a support such 
as silica gels, aluminum oxides, solid aluminoxane or other inorganic 
support materials such as magnesium chloride or else a polyolefin powder 
in finely divided form and is then reacted with the metallocene. 
If the polymerization is carried out as a suspension or solution 
polymerization, an inert solvent customary for the Ziegler low-pressure 
process is used. For example, the polymerization is carried out in an 
aliphatic or cycloaliphatic hydrocarbon; examples which may be mentioned 
are propane, butane, hexane, heptane, isooctane, cyclohexane, 
methylcyclohexane. Furthermore, a petroleum or hydrogenated diesel oil 
fraction can also be used. It is also possible to use toluene. Preference 
is given to carrying out the polymerization in the liquid monomer. 
Use of hydrogen or increasing the polymerization temperature also makes it 
possible to obtain polyolefins of low molecular weight, for example waxes, 
whose hardness or melting point can be varied by means of the comonomer 
content. Selection of the polymerization process and the type(s) of 
comonomer(s), and also the amount(s) of comonomer(s), enable olefin 
copolymers having elastomeric properties, e.g. 
ethylene/propylene/1,4-hexadiene terpolymers, to be prepared.

The following examples illustrate the invention. 
1) 2,2-Bisindenylpropane 
100.0 g (0.86 mol) of indene are dissolved in 400 ml of toluene and a 
solution of 86.2 g (2.2 mol) of sodium hydroxide and 19.6 g (86 mmol) of 
triethylbenzylammonium chloride in 86.2 ml of water (50% strength NaOH 
solution) is then added. The addition of 25.0 g (0.43 mol) of acetone is 
carried out dropwise over a period of 30 minutes. After a reacting time of 
5 hours, the aqueous phase is separated off, extracted twice with 100 ml 
each time of diethyl ether and the combined organic phases are dried over 
MgSO.sub.4. The solvent is removed under reduced pressure and the crude 
product is purified by recrystallization from toluene/hexane. This gives 
99.6 g of 2,2-bisindenylpropane in 85% yield in the form of a yellow 
powder. 
.sup.1 H-NMR (200 MHz, CDCl.sub.3): 7.4-6.9 (m, 8H, arom. H), 6.42 (s, 2H, 
olefin, H), 3.35 (s, 4H, CH.sub.2), 1.70 (s, 6H, CH.sub.3). Mass spectrum: 
272 M.sup.+, correct disintegration pattern. 
2) 1,1-Bisindenylethane 
100.0 g (0.86 mol) of indene are dissolved in 400 ml of toluene and a 
solution of 86.2 g (2.2 mol) of sodium hydroxide and 19.6 g (86 mmol) of 
triethylbenzylammonium chloride in 86.2 ml of water (50% strength NaOH 
solution) is then added. The addition of 18.9 g (0.43 mol) of acetaldehyde 
is carried out dropwise over a period of 30 minutes. After a reaction time 
of 5 hours, the aqueous phase is separated off, extracted twice with 100 
ml each time of diethyl ether and the combined organic phases are dried 
over MgSO.sub.4. The solvent is removed under reduced pressure and the 
crude product is purified by recrystallization from toluene/hexane. This 
gives 91.5 g of 1,1-bisindenylethane in 82% yield in the form of a yellow 
powder. 
.sup.1 H-NMR (200 MHz, CDCl.sub.3): 7.3-6.9 (m, 8H, arom. H), 6.47 (s, 2H, 
olefin H), 3.41 (s, 4H, CH.sub.2), 3.10 (s, 1H, CH), 1.65 (s, 3H, 
CH.sub.3). Mass spectrum: 259 M.sup.+, correct disintegration pattern. 
3) Isopropylidenebis(1-indenyl)zirconium dichloride 
A solution of 10 g (37 mmol) of 2,2-bisindenylpropane in 30 ml of diethyl 
ether is admixed at room temperature under argon protection with 29.6 ml 
(74 mmol) of a 2.5M butyllithium solution in hexane and stirred overnight. 
After addition of 20 ml of hexane, the beige suspension is filtered and 
the residue is washed with 20 ml of pentane. The dilithio salt is dried in 
an oil pump vacuum and then added at -78.degree. C. to a suspension of 8.6 
g (37 mmol) of ZrCl4 in dichloromethane. The mixture is warmed to room 
temperature over a period of 1 hour and stirred for a further 30 minutes 
at this temperature. After taking off the solvent, the orange-brown 
residue is extracted with 50 ml of toluene. Taking off the solvent gives 
8.8 g (55%) of an orange powder. The ratio of racemate to meso form was 
determined as 2:1. Recrystallization from toluene enable 4.1 g (26%) of 
the pure racemate to be obtained. 
.sup.1 H-NMR (200 MHz, CDCl.sub.3): 7.8-6.9 (m, 8H, arom. H), 6.72 (m, 2H, 
Cp-H), 6.17 (m, 2H, Cp-H), 2.15 (s, 6H, CH.sub.3). Mass spectrum: 432 
M.sup.+, correct disintegration pattern.