Monocyclopentadienyl complexes The present invention relates to monocyclopentadienyl complexes in which the cyclopentadienyl system bears at least one bridged donor and at least one aryl group and to a catalyst system comprising at least one of the monocyclopentadienyl complexes, and also to processes for pre- paring them.

In addition, the invention provides for the use of the catalyst system for the polymerization or co- polymerization of olefins and provides a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the catalyst system and provides polymers obtain- able in this way.

Many of the catalysts used for the polymerization of a-olefins are based on immobilized chromium oxides (cf. , for example, Kirk-Othmer, "Encyclopedia of Chemical Technology", 1981, Vol. 16, p.

402). These generally give ethylene homopolymers and copolymers having high molecular weights but are relatively insensitive to hydrogen and thus do not allow the molecular weight to be controlled in a simple fashion. In contrast, the molecular weight of polyethylene can be controlled in a simple way by addition of hydrogen when using bis (cyclopentadienyl) chromium (US 3,709, 853), bis (indenyl) chromium or bis (fluorenyl) chromium (US 4,015, 059) applied to an inor- ganic, oxidic support.

As in the case of the Ziegler-Natta systems, there is now also a search for catalyst systems hav- ing a uniquely defined, active center, known as single site catalysts, in the case of the chromium compounds. The intention is to allow the activity, copolymerization behavior of the catalyst and the properties of the polymers obtained in this way to be altered in a simple fashion by target variation of the ligand framework.

DE 197 10615 describes monocyclopentadienylchromium compounds substituted by donor lig- ands which can be used for the polymerization of both ethene and propene. The donor is in this case from group 15 and uncharged. The donor is bound to the cyclopentadienyl ring via a (ZR2) n fragment, where R is hydrogen, alkyl or aryl, Z is an atom of group 14 and n is > 1. DE 196 30 580 specifically claims Z = carbon in combination with an amine donor.

WO 96/13529 describes reduced transition metal complexes of elements of groups 4 to 6 of the Periodic Table with polydentate monoanionic ligands. These also include cyclopentadienyl ligands containing a donor function. The examples are restricted to titanium compounds.

WO01/12641 describes monocyclopentadienyl complexes of chromium, molybdenum and tung- sten which bear, in particular, quinolyl or pyridyl donors which are bound either directly or via a Ci or Si bridge to the cyclopentadienyl system.

WO 01/92346 discloses cyclopentadienyl complexes of elements of groups 4-6 of the Periodic Table of the Elements in which a dihydrocarbyl-Y group, where Y is an element of group 14 of the Periodic Table of the Elements, which bears particular Lewis bases is bound to the cyclopentadi- enyl system.

The abovementioned catalyst systems are not yet optimized in terms of their activities. Further- more, the polymers and copolymers formed usually have very high molecular weights.

It is an object of the present invention to discover further transition metal complexes based on cyclopentadienyl ligands bearing a bridged donor which are. suitable for the polymerization of olefins and display very high activities. A further object of the invention is to find an advantageous process for preparing such complexes.

We have found that this object is achieved by monocyclopentadienyl complexes comprising the structural feature of the formula Cp-YmMA (I), where the variables have the following meanings: Cp is a cyclopentadienyl system having an aryl substituent, Y is a substituent which is bound to Cp and contains at least one uncharged donor con- taining at least one atom of group 15 or 16 of the Periodic Table, MA is titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten or an element of group 3 of the Periodic Table and the lanthanides and m is 1, 2 or 3.

Furthermore, we have found a catalyst system comprising the monocyclopentadienyl complexes of the present invention, the use of the monocyclopentadienyl complexes or of the catalyst system for the polymerization or copolymerization of olefins and a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the monocyclopentadienyl com- plex or of the catalyst system and polymers obtainable in this way. Furthermore, a process and intermediates in this process have been found.

The monocyclopentadienyl complexes of the present invention comprise the structural element of the formula Cp-YmMA (I), where the variables are as defined above. Further ligands can conse- quently be bound to the metal atom MA. The number of further ligands depends, for example, on

the oxidation state of the metal atom. The ligands are not further cyclopentadienyl systems. Suit- able ligands ere monoanionic and dianionic ligands as described by way of example for X. In ad- dition, Lewis bases such as amines, ethers, ketones, aldehydes, esters, sulfides or phosphines may be bound to the metal center M. The monocyclopentadienyl complexes can be in monomeric, dimeric or oligomeric form. The monocyclopentadienyl complexes are preferably in monomeric form.

MA is a metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, nio- bium, tantalum, chromium, molybdenum and tungsten. The oxidation states of the transition met- als MA in catalytically active complexes are usually known to those skilled in the art. Chromium, molybdenum and tungsten are very probably present in the oxidation state +3, titanium, zirco- nium, hafnium and vanadium in the oxidation state 4, with titanium and vanadium also being able to be present in the oxidation state 3. However, it is also possible to use complexes whose oxida- tion state does not correspond to that of the active catalyst. Such complexes can then be appro- priately reduced or oxidized by means of suitable activators. MA is preferably titanium, vanadium, chromium, molybdenum or tungsten. Particular preference is given to chromium in the oxidation states 2,3 and 4, in particular 3. m can be 1,2 or 3, i. e. 1,2 or 3 donor groups Y can be bound to Cp. If 2 or 3 Y groups are pre- sent, these can be identical or different. Preference is given to only one donor group Y being bound to Cp (m = 1).

The uncharged donor Y is an uncharged functional group containing an element of group 15 or 16 of the Periodic Table or a carbene, e. g. amine, imine, carboxamide, carboxylic ester, ketone (oxo), ether, thioketone, phosphene, phosphite, phosphine oxide, sulfonyl, sulfonamide, carbenes such as N-substituted imidazol-2-ylidene or unsubstituted, substituted or fused, partially unsatu- rated heterocyclic or heteroaromatic ring systems. The donor Y can be bound intermolecularly or intramolecularly to the transition metal MA or not be bound to it. Preference is given to the donor Y being bound intramolecularly to the metal center MA. Particular preference is given to the mono- cyclopentadienyl complexes comprising the structural element of the formula Cp-Y-MA.

Cp is a cyclopentadienyl system which can bear any substituents and/or be fused with one or more aromatic, aliphatic, heterocyclic or heteroaromatic rings, with 1,2 or 3 substituents, prefera- bly 1 substituent, being formed by the group Y and/or 1,2 or 3 substituents, preferably 1 substitu- ent, being substituted by the group Y and/or the aromatic, aliphatic, heterocyclic or heteroaromatic fused ring being 1,2 or 3 substituents Y, preferably 1 substituent Y. Furthermore, the cyclopenta- dienyl system bears one or more aromatic substituents which are not fused to Cp and particularly preferably bears an aromatic substituent and/or the aromatic, aliphatic, heterocyclic or heteroaro- matic fused ring bears 1,2 or 3 aromatic substituents, preferably 1 aromatic substituent. The aromatic substituent is preferably bound to the cyclopentadienyl skeleton. The cyclopentadienyl

skeleton itself is a C5 ring system having 6 7C-electrons, with one of the carbon atoms also being able to be replaced by nitrogen or phosphorus, preferably phosphorus. Preference is given to using C5 ring systems which do not have a carbon atom replaced by a heteroatom. It is possible, for example, for a heteroaromatic containing at least one atom from the group consisting of N, P, O and S or an aromatic to be fused to this cyclopentadienyl skeleton. In this context, "fused to" means that the heterocycle and the cyclopentadienyl skeleton share two atoms, preferably carbon atoms. The cyclopentadienyl system is bound to MA.

The aromatic substituent is preferably a C6-C22-ary) or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, with the aromatic substituent also being able to be substituted by N-, P-, O-or S-containing substituents, C-C2z-alkyl, C2-C22-alkenyl, halogens or haloalkyl or haloaryls having 1-10 carbon atoms.

Particularly useful monocyclopentadienyl complexes are ones in which Y is formed by the group -Zk-A-and together with the cyclopentadienyl system Cp and MA forms a monocyclopentadienyl complex comprising the structural element of the formula Cp-Zk-A-MA (II), where the variables have the following meanings: Cp-Zk-A is where the variables have the following meanings: E1A-E5A are each carbon or not more than one ERA to E5A is phosphorus, R1A-R4A are each, independently of one another, hydrogen, C-C22-alkyl, C2-C22-aikenyl, C6-C22- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl radical and 6-20 carbon at- oms in the aryl radical, NR5A2, N (SiR5A3)2, OR5A, OSiR5A3, SiR5A3, BR5A2, where the or- ganic radicals R1A-R4A may also be substituted by halogens and two vicinal radicals R1A- R4A may also be joined to form a five-, six-or seven-membered ring, and/or two vicinal radicals R1A-R4A are joined to form a five-, six-or seven-membered heterocycle which contains at least one atom from the group consisting of N, P, O or S and at least one R1A-R4A is a C6-C22-aryl, where the aryl may also be substituted by N-, P-, O-or S-

containing substituents, C1-C22-alkyl, C2-C22-alkenyl, halogens or haloalkyl or haloaryis having 1-10 carbon atoms, RUA the radicals R5A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20- alkenyl, C6-C2o-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two geminal radicals R5A may also be joined to form a five-or six-membered ring, Z is a divalent bridge between A and Cp selected from the group consisting of -BR6A-, -BNR6AR7A, -AIR6A-, -Sn-, -O-, -S-, -SO-, -SO2-, -NR6A-, -CO-, - PR6A-or-P (O) R6A-, where are each, independently of one another, silicon or germanium, R6A-R11A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6-C20- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR12A3, where the organic radicals R6A-R11A may also be substituted by halogens and two geminal or vicinal radicals R6A-R11A may also be joined to form a five-or six-membered ring and

R12A the radicals R12A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- Cao-alkenyl,; C6-C20-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, C1-C10-alkoxy or C6-C10-aryloxy and two radi- cals R12A may also be joined to form a five-or six-membered ring, and A is an uncharged donor group containing one or more atoms of group 15 and/or 16 of the Periodic Table of the Elements or a carbene, preferably an unsubstituted, substituted or fused, heteroaromatic ring system, MA is a metal selected from the group consisting of titanium in the oxidation state 3, vana- dium, chromium, molybdenum and tungsten and k is 0 or 1.

In preferred cyclopentadienyl systems Cp, all E1A to E5A are carbon.

The polymerization behavior of the metal complexes can be influenced by varying the substituents R1A-R4A. The type and number of the substituents can influence the ability of the olefins to be po- lymerized to gain access to the metal atom Ma. It is possible in this way to modify the activity and selectivity of the catalyst in respect of various monomers, in particular bulky monomers. Since the substituents can also influence the rate of termination reactions of the growing polymer chain, the molecular weight of the polymers being formed can also be altered in this way. One of the sub- stituents R1A-R4A is always a C6-C22-aryl or an alkylaryl having from 1 to 10 carbon atoms in the alkyl radical and 6-20 carbon atoms in the aryl radical in order to achieve the desired results. The remaining substituents can be varied widely. Examples of possible carboorganic substituents R1A- R4A are the following : hydrogen, C-C22-alkyl which may be linear or branched, e. g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5-to 7-membered cycloalkyl which may in turn bear a C1-C10-alkyl group and/or a C6-C1D-aryl group as substituent, e. g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C2-C22-alkenyl which may be linear, cyclic or branched and in which the double bond can be internal or terminal, e. g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C6-C22-aryl which may be substituted by further alkyl groups, e. g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p- methylphenyl, 2,3-, 2,4-, 2, 5-, or 2, 6-dimethylphenyl, 2,3, 4-, 2,3, 5-, 2, 3,6-, 2,4, 5-, 2,4, 6- or 3,4, 5- trimethylphenyl, and arylalkyl which may be substituted by further alkyl groups, e. g. benzyl, o-, m-, p-methylbenzyl, 1-or 2-ethylphenyl, where two of the radicals RUZ to R4A may also be joined to form a 5-, 6-or 7-membered ring and/or two of the vicinal radicals R, A-R 4A may be joined to form a five-, six-or seven-membered heterocycle which contains at least one atom from the group consisting of N, P, O or S and/or the organic radicals R1A-R4A may also be substituted by halo- gens such as fluorine, chlorine or bromine. Furthermore, R1A-R4A can also be amino NR5A2, or

N (SiR5A3) 2, alkoxy or aryloxy OR5A, for example dimethylamio, N-pyrrolidinyl, picolinyl, methoxy, ethoxy or isopropoxy. In organosilicon substituents SiR5A3, the radicals R5A can be the same car- boorganic radicals as described in more detail above for RtA-R4A, where two R5A may also be joined to form a 5-or 6-membered ring, e. g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributyi- silyl, tri-tert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. These SiR5A3 radicals can also be bound to the cyclopentadienyl skeleton via an oxygen or nitrogen, for example trimethyl- silyloxy, triethylsilyloxy, butyldimethylsilyloxy, tributylsilyloxy or tri-tert-butylsilyloxy. Preferred radi- cals R1A-R4A are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, ortho-dialkyl- or -dichloro-substituted phenyl, trialkyl-or trichloro-substituted phenyl, naphthyl, biphenyl and anthranyl. Particularly useful or- ganosilicon substituents are trialkylsilyl groups having from 1 to 10 carbon atoms in the alkyl radi- cal, in particular trimethylsilyl groups.

Two vicinal radicals R'A-R4A together with the atoms E1A E5A bearing them form a heterocycle, preferably a heteroaromatic, which contains at least one atom from the group consisting of nitro- gen, phosphorus, oxygen and sulfur, particularly preferably nitrogen and/or sulfur, with preference being given to the atoms E1A-EsA present in the heterocycle or heteroaromatic being carbon. Pref- erence is given to heterocycles and heteroaromatics having a ring size of 5 or 6 ring atoms. Ex- amples of 5-membered heterocycles which have from one to four nitrogen atoms and/or a sulfur or oxygen atom in addition to carbon atoms as ring members are 1,2-dihydrofuran, furan, thio- phene, pyrrole, isoxazole, 3-isothiazole, pyrazol, oxazole, thiazole, imidazole, 1,2, 4-oxadiazole, 1,2, 5-oxadiazole, 1,3, 4-oxadiazole, 1,2, 3-triazole and 1,2, 4-triazole. Examples of 6-membered heteroaryl groups which may contain from one to four nitrogen atoms and/or a phosphorus atom are pyridine, phosphobenzene, pyridazine, pyrimidine, pyrazine, 1,3, 5-triazine, 1,2, 4-triazine or 1,2, 3-triazine. The 5-membered and 6-membered heterocycles can also be substituted by C1-C10- alkyl, C6-C10-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-10 carbon atoms in the aryl part, trialkylsilyl or halogens such as fluorine, chlorine or bromine, dialkylamide, alkylarylamide, diarylamide, alkoxy or aryloxy or be fused with one or more aromatics or het- eroaromatics. Examples of benzo-fused 5-membered heteroaryl groups are indole, indazole, ben- zofuran, benzothiophene, benzothiazole, benzoxazole and benzimidazole. Examples of benzo- fused 6-membered heteroaryl groups are chromane, benzopyran, quinoline, isoquinoline, cinno- line, phthalazine, quinazoline, quinoxaline, 1, 10- phenanthroline and quinolizine. Naming and numbering of the heterocycles has been taken from Lettau, Chemie der Heterocyclen, 15t edition, VEB, Weinheim 1979. The heterocycles/heteroaromatics are preferably fused with the cyclope- tadienyl skeleton via a C-C double bond of the heterocycle/heteroaromatic. Heterocy- cles/heteroaromatics having one heteroatom are preferably 2, 3- or b-fused.

Cyclopentadienyl systems Cp having a fused heterocycle are, for example, thiapentalene, methyl- thiapentalene, ethylthiapentalene, isopropylthiapentalene, n-butylthiapentalene, tert-butyl- thiapentalene, trimethylsilylthiapentalene, phenylthiapentalene, naphthylthiapentalene, methylthio-

pentalene, azapentalene, methylazapentalene, ethylazapentalene, isopropylazapentalene, n-bu- tylazapentalene, trimethylsilylazapentalene, phenylazapentalene, naphthylazapentalene, oxapen- talene or phosphapentalene.

The synthesis of such cyclopentadienyl systems having a fused-on heterocycle is described, for example, in the abovementioned WO 98/22486. In"metalorganic catalysts for synthesis and po- lymerisation", Springer Veriag 1999, Ewen et ai., p. 150 ff, describe further syntheses of these cyclopentadienyl systems.

Particularly preferred substituents R1A-R4A are the above-described carboorganic substituents and the carboorganic substituents which form a cyclic fused ring system, i. e. together with the E1A-E5A skeleton, preferably together with a C5cyclopentadienyl skeleton, form, for example, an unsubstituted or substituted indenyl, benzindenyl, phenanthrenyl or tetrahydroindenyl system, and in particular their preferred embodiments.

Examples of such cyclopentadienyl systems (without the group-Z-A-, which is preferably located in the 1 position, and without the aryl substituents) are monoalkylcyclopentadienyl systems, e. g.

3-methylcyclopentadienyl, 3-ethylcyclopentadienyl, 3-isopropylcyclopentadienyl, 3-tert- butylcyclopentadienyl, dialkylcyclopentadienyl systems, e. g. tetrahydroindenyl, 2, 4-dimethyl- cyclopentadienyl or 3-methyl-5-tert-butylcyclopentadienyl, or trialkylcyclopentadienyl systems, e. g.

2,3, 5-trimethylcyclopentadienyl, and also indenyl or benzoindenyl. The fused ring system may bear further C1-C20-alkyl, C2-C20-alkenyl, C5-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, NR5A2, N (SiR5A3)2, OR5A, OSiR5A3 or SiR5A3 substituents, e. g. 4-methylindenyl, 4-ethylindenyl, 4-isopropylindenyl, 5-methylindenyl, 4- phenylindenyl, 5-methyl-4-phenylindenyl or 4-naphthylindenyl.

One of the substituents R1A-R4A, preferably R2A, is a C6-C22-aryl group or an alkylaryl group hav- ing from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, preferably a C6-C22-aryl group such as phenyl, naphthyl, biphenyl, anthracenyl or phenanthrenyl, where the aryl may also be substituted by N-, P-, O-or S-containing substituents, C-C22-alkyl, C2-C22- alkenyl, halogens or haloalkyl or haloaryls having 1-10 carbon atoms, for example o-, m-, p- methylphenyl, 2,3-, 2,4-, 2, 5- or 2, 6-dimethylphenyl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3, 4,5- trimethylphenyl, o-, m-, p-dimethylaminophenyl, o-, m-, p-methoxyphenyl, o-, m-, p-fluorophenyl, o-, m-, p-chlorophenyl, o-, m-, p-trifluoromethylphenyl, 2,3-, 2,4-, 2,5-, or 2, 6-difluorophenyl,, 2,3-, 2, 4-, 2, 5- or 2, 6-dichlorophenyl or 2,3-, 2, 4-, 2,5-, or 2, 6-di (trifluoromethyl) phenyl. The N-, P-, O- or S-containing substituents, C1-C22-alkyl, C2-C22-alkenyl, halogens or haloalkyl or haloaryls hav- ing 1-10 carbon atoms as substituents on the aryl radical are preferably located in the para posi- tion relative to the bond to the cyclopentadienyl ring. The aryl substituent can be bound in the vicinal position to the substituent-Z-A or the two substituents are located in the 1,3 position rela- tive to one another on the cyclopentadienyl ring. Preference is given to-Z-A and the aryl sub-

stituent being located in the 1,3 positions relative to one another on the cyclopentadienyl ring. zu As in the cases of the metallocenes, the monocyclopentadienyl complexes of the present inven- tion can be chiral. Thus, either one of the substituents R'A-R4A on the cyclopentadienyl skeleton can bear one or more chiral centers or else the cyclopentadienyl system Cp can itself be enantio- topic, so that the chirality is induced only when it is bound to the transition metal M (for the con- ventions regarding chirality in cyclopentadienyl compounds, see R. Halterman, Chem. Rev. 92, (1992), 965-994).

The bridge Z between the cyclopentadienyl system Cp and the uncharged donor A is an organic divalent bridge (k=1), preferably consisting of carbon-and/or silicon-and/or boron-containing bridge members. Changing the length of the link between the cyclopentadienyl system and A enables the activity of the catalyst to be influenced.

Possible carboorganic substituents R6A-R"A on the link Z are, for example the following : hydro- gen, C,-C2o-alky ! which may be linear or branched, e. g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5-to 7- membered cycloalkyl which may in turn bear a C6-C, 0-aryl group as substituent, e. g. cyclopropyl, cyclobutyl, cyc, openty"cyc, ohexyl, cycloheptyl, cyclooctyl, cyclononyi or cyclododecyl, C2-C20- alkenyl which may be linear, cyclic or branched and in which the double bond can be internal or terminal, e. g. vinyl, 1-allyl, 2-allyl, 3-allyi, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C6-C20-aryl which may be substituted by further alkyl groups, e. g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5-, or 2, 6-dimethylphen- 1-yi, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3,4, 5-trimethylphen-1-yl, or arylalkyl which may be sub- stituted by further alkyl groups, e. g. benzyl, o-, m-, p-methylbenzyl, 1-or 2-ethylphenyl, where two radicals R6A to R'1A may also be joined to form a 5-or 6-membered ring, for example cyclohex- ane, and the organic radicals R6A-R"A may also be substituted by halogens such as fluorine, chlo- rine or bromine, for example pentafluorophenyl or bis-3, 5-trifluoromethylphen-1-yl, and alkyl or aryl.

In organosilicon substituents SiR'2A3, possible radicals R'2A are the same radicals mentioned in more detail above for R6A-R'1A, where two R12A may also be joined to form a 5-or 6-membered ring, e. g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributsylsilyl, tri-tert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. Preferred radicals R 12A are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, benzyl, phenyl, ortho-dialkyl-or- dichloro-substituted phenyls, trialkyl-or trichloro-substituted phenyls, naphthyl, biphenyl and an- thranyl.

Particularly preferred substituents R6A to RA are hydrogen, C1-C20-alkyl which may be linear or branched, e. g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-

heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl C6-Czo-aryl which may be substituted by further alkyl groups, e. g.. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methyfphenyl, 2,3-, 2,4-, 2,5-, or 2,6- dimethylphen-1-yl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3,4, 5-trimethylphen-1-yl, or arylalkyl which may be substituted by further alkyl groups, e. g. benzyl, o-, m-, p-methylbenzyl, 1-or 2- ethylphenyl, where two radicals R6A to R"A may also be joined to form a 5-or 6-membered ring, for example cyclohexane, and the organic radicals R6A-R"A may also be substituted by halogens such as fluorine, chlorine or bromine, in particular fluorine, for example pentafluorophenyl or bis- 3, 5-trifluoromethylphen-1-yl, and alkyl or aryl. Particular preference is given to methyl, ethyl, 1- propyl, 2-isopropyl, 1-butyl, 2-tert-butyl, pheny) and pentafluorophenyl.

Z is preferably a -CR6AR7A-, -SiR6AR7A- group, in particular-Si (CH3) 2-,-CR6ARACRSAR9A-, -SiR6AR7ACR8AR9A- or substituted or unsubstituted 1, 2-phenylene and in particular -CR6AR7A-.

Here, the preferred embodiments of the substituents R6A to R'1A described above are likewise preferred embodiments.-CR6AR7A-is preferably a-CHR6A-,-CH2-or-C (CH3) 2- group. The group -SiR6AR7A-in-L'AR3AR7ACR8AR9A-can be bound to the cyclopentadienyl system or to A. This group-SiR6AR7A-or its preferred embodiments is preferably bound to Cp. k is 0 or 1, and is in particular equal to 1 or when A is an unsubstituted, substituted or fused, het- erocyclic ring system can also be 0.

A is an uncharged donor containing an atom of group 15 or 16 of the Periodic Table or a carbene, preferably one or more atoms selected from the group consisting of oxygen, sulfur, nitrogen and phosphorus, preferably nitrogen and phosphorus. The donor function in A can be bound intermo- lecularly or intramolecularly to the metal MA. The donor in A is preferably bound intramolecularly to M. Possible donors are uncharged functional groups containing an element of group 15 or 16 of the Periodic Table, e. g. amine, imine, carboxamide, carboxylic ester, ketone (oxo), ether, thioke- tone, phosphine, phosphite, phosphine oxide, sulfonyl, sulfonamide, carbenes such as N- substituted imidazol-2-ylidene or unsubstituted, substituted or fused, heterocyclic ring systems.

The synthesis of the bond from A to the cyclopentadienyl radical and Z can be carried out, for example, by a method analogous to that of WO 00/35928. A is preferably a group selected from among -OR13A-, -SR13A-, -NR13AR14A-, PR13AR14A-, -C=NR13A- and unsubstituted, substituted or fused heteroaromatic ring systems, in particular-NR'3ARl4A-,-C=NR13A-and unsubstituted, substi- tuted or fused heteroaromatic ring systems.

R'3A and R'4A are each, independently of one another, hydrogen, C1-C20-alkyl which may be linear or branched, e. g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyi, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5-to 7-membered cycloalkyl which may in turn bear a C6-C10-aryl group as substituent, e. g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C2-C20-alkenyl which may be linear, cyclic or branched and in which the double bond may. be internal or terminal, e. g. vinyl, 1-allyl, 2-allyl, 3-

allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C6- C20-aryl which may be substituted by further alkyl groups, e. g. phenyl, naphthyl, biphenyl, an- thranyl, o-, m-, p-methylphenyl, 2, 3-, 2,4-, 2, 5-, or 2, 6-dimethylphen-1-yl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2, 4, 6- or 3,4, 5-trimethylphen-1-yl, a, kylaryl which has from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and may be substituted by further alkyl groups, e. g. benzyl, o-, m-, p-methylbenzyl, 1-or 2-ethylphenyl, or SiR 15A 3, where the organic radicals R13A-R'4A may also be substituted by halogens, e. g. fluorine, chlorine or bromine, or nitrogen- containing groups and further C-C2O-alkyl, C2-C2o-alkenyl, C6-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR15A3 groups and two vicinal radicals R'3A-R14A may also be joined to form a five-or six-membered ring and the radicals R'5A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6- C20-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or two radicals R'5A may also be joined to form a five-or six-membered ring.

NR13AR14A is an amide substituent. It is preferably a secondary amide such as dimethylamide, N- ethylmethylamide, diethylamide, N-methylpropylamide, N-methylisopropylamide, N- ethylisopropylamide, dipropylamide, diisopropylamide, N-methylbutylamide, N-ethylbutylamide, N- methyl-tert-butylamide, N-tert-butylisopropylamide, dibutylamide, di-sec-butylamide, diisobutyla- mide, tert-amyl-tert-butylamide, dipentylamide, N-methy, hexylamide, dihexylamide, tert-amyl-tert- octylamide, dioctylamide, bis (2-ethylhexyl) amide, didecylamide, N-methyloctadecylamide, N- methylcyclohexylamide, N-ethylcyclohexylamide, N-isopropylcyclohexylamide, N-tert- butylcyclohexylamide, dicyclohexylamide, pyrrolidine, piperidine, hexamethylenimine, decahydro- quinoline, diphenylamine, N-methylanilide or N-ethylanilide.

In the imino group-C=NR'3A, R13A is preferably a Cs-C2o-aryl radical which may be substituted by further alkyl groups, e. g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylpheny., 2, 3-, 2,4-, 2,5-, or 2, 6-dimethylphen-1-yl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3, 4, 5-trimethylphen-1-yl.

A is preferably an unsubstituted, substituted or fused heteroaromatic ring system which may com- prise, apart from carbon ring atoms, heteroatoms from the group consisting of oxygen, sulfur, nitrogen and phosphorus. Examples of 5-membered heteroaryl groups which may, in addition to carbon atoms, contain from one to four nitrogen atoms or from one to three nitrogen atoms and/or one sulfur or oxygen atom as ring members are 2-fury, 2-thienyl, 2-pyrrolyl, 3-isoxazolyl, 5- isoxazolyl, 3-isothiazolyl, 5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazoly, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl, 4-imidazolyl, 5- imidazolyl, 1,2, 4-oxadiazol-3-yl, 1, 2, 4-oxadiazol-5-yl, 1,3, 4-oxadiazol-2-yl or 1,2, 4-triazol-3-yl.

Examples of 6-membered heteroaryl groups which can contain from one to four nitrogen atoms and/or a phosphorus atom are 2-pyridinyl, 2-phosphabenzolyl 3-pyridazinyl, 2-pyrimidinyl, 4- pyrimidinyl, 2-pyrazinyl, 1,3, 5-triazin-2-yl and 1,2, 4-triazin-3-yl, 1, 2, 4-triazin-5-yl or 1,2, 4-triazin-6- yl. The 5-membered and 6-membered heteroaryl groups can also be substituted by Cl-Clc,-alkyl, C6-C10-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-10 carbon atoms in

the aryl part, trialkylsilyl or halogens such as fluorine, chlorine or bromine or be fused with one or more aromatics or heteroaromatics. Examples of benzo-fused 5-membered heteroaryl groups are <BR> <BR> 2-indolyl, 7-indolyl, 2-coumaronyl, 7-coumaronyl, 2-thianaphthenyl, 7-thianaphthenyl, 3-indazolyl, 7-indazolyl, 2-benzimidazolyl and 7-benzimidazolyl. Examples of benzo-fused 6-membered het- eroaryl groups are 2-quinolyf, 8-quinolyl, 3-cinnolyl, 8-cinnolyl, 1-phthalazyl, 2-quinazolyl, 4- quinazolyl, 8-quinazolyl, 5-quinoxalyl, 4-acridyl, 1-phenanthridyl or 1-phenazyl. Naming and num- bering of the heterocycles has been taken from L. Fieser and M. Fieser, Lehrbuch der organischen Chemie, 3'd revised edition, Verlag Chemie, Weinheim 1957.

Among these heteroaromatic systems A, particular preference is given to unsubstituted, substi- tuted and/or fused six-membered heteroaromatics having 1,2, 3,4 or 5 nitrogen atoms in the heteroaromatic part, in particular substituted and unsubstituted 2-pyridyl, 2-quinolyl or 8-quinolyl.

A is therefore preferably a group of the formula (IVa) or (IVb) , where E6A-E"A are each, independently of one another, carbon or nitrogen, R16A-R21A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6-C20- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR 3, where the organic radicals R'-R may also be substituted by halogens or nitrogen and further C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR22A3 groups and two vicinal radicals R16A-R21A or R'6A and Z may also be joined to form a five-or six-membered ring and R22A the radicals R22A are each, independently of one another, hydrogen, Cl-C2o-alkyl, C2- C2o-alkenyl, C6-C2o-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R22A mày also be joined to form a five-or six-membered ring and p is 0 when E6A-E"A is nitrogen and is 1 when E6A-E"A is carbon.

In particular, 0 or 1 of E6A-E11Å is nitrogen and the remainder are carbon. A is particularly prefera- bly 2-pyridyl t6-methyl-2-pyridyl, 4-methyl-2-pyridyl, 5-methyl-2-pyridyl, 5-ethyl-2-pyridyl, 4,6- dimethyl-2-pyridyl, 3-pyridazyl, 4-pyrimidyl, 6-methyl-4-pyrimidyl, 2-pyrazinyl, 6-methyi-2- pyrazinyl, 5-methyl-2-pyrazinyl, 3-methyl-2-pyrazinyl, 3-ethylpyrazinyl, 3,5, 6-trimethyl-2-pyrazinyl, 2-quinolyl, 4-methyl-2-quinolyl, 6-methyl-2-quinolyl, 7-methyl-2-quinolyl, 2-quinoxalyl or 3-methyl- 2-quinoxalyl.

Owing to the ease of preparation, a preferred combination of Z and A is when Z is an unsubsti- tuted or substituted 1, 2-phenylene group and A is NR'6AR'7A, and also the combination in which Z is-CHR6A-,-CH2-,-C (CH3) z or-Si (CH3) 2- and A is unsubstituted or substituted 2-quinolyl or un- substituted or substituted 2-pyridyl. Systems which do not have a bridge Z and in which k is 0 are also particularly simple to obtain. In this case, A is preferably a substituent of the formula (IVb) and in particular unsubstituted or substituted 8-quinolyl. The above-described preferred embodi- ments of the variables are also preferred in these preferred combinations., MA is a metal selected from the group consisting of titanium in the oxidation state 3, vanadium, chromium, molybdenum and tungsten, preferably titanium in the oxidation state 3 and chromium.

Particular preference is given to chromium in the oxidation states 2,3 and 4, in particular 3. The metal complexes, in particular the chromium complexes, can be obtained in a simple manner by reacting the corresponding metal salts, e. g. metal chlorides, with the ligand anion (e. g. using a method analogous to the examples in DE 197 10615).

Among the suitable monocyclopentadienyl complexes, preference is given to those of the formula Cp-YmMAXAn (V), where the variables Cp, Y, A, m and MA are as defined above and their pre- ferred embodiments are also preferred here and: XA the radicals XA are each, independently of one another, fluorine, chlorine, bromine, io- dine, hydrogen, Cl-Clo-alkyl, C2-Clo-alkenyl, C6-C20-aryl, alkylaryl having 1-10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, NR23AR24A, OR23A, SR23A, SO3R23A, OC (O) Ra3A, CN, SCN, p-diketonate, CO, BF4-, PF6 or bulky noncoordinating anions or two radica, s XA form a substituted or unsubstituted diene ligand, in particular a 1, 3-diene ligand, and the radicals XA may be joined to one another, R23A-R24A are each, independently of one another, hydrogen, C-C2o-aikyl, C2-C20-alkenyl, C6-C20- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, SiR25A3, where the organic radica, s R23A-R24A may also be substituted by halogens or nitrogen-and oxygen-containing groups and two radicals R23A-R24A may also be joined to form a five-or six-membered ring,

R25A the radicals R25A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- C20-alkenyl, C6-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two'radicals R 25A may also be joined to form a five-or six-membered ring and n is1, 1, 2 or 3.

The embodiments and preferred embodiments of Cp, Y, Z, A, m and MA indicated above also apply individually and in combination to these preferred monocyclopentadienyl complexes.

The ligands XA result from, for example, the choice of the metal compounds used as starting ma- terials for the synthesis of the monocyclopentadienyl complexes, but can also be varied subse- quently. Possible ligands XA are, in particular, the halogens such as fluorine, chlorine, bromine or iodine, in particular chlorine. Alkyl radicals such as methyl, ethyl, propyl, butyl, vinyl, allyl, phenyl or benzyl are also advantageous ligands XA. As further ligands XA, mention may be made, purely by way of example and in no way exhaustively, of trifluoroacetate, BF4-, PF6-and weakly coordi- nating or noncoordinating anions (cf. , for example, S. Strauss in Chem. Rev. 1993,93, 927-942) such as B (C6F5) 4-.

Amides, alkoxide, sulfonates, carboxylates and p-diketonates are also particularly suitable ligands XA, Variation of the radicals R 23A and R 24A makes it possible, for example, to make fine adjustments in physical properties such as solubility. Possible carboorganic substituents R23A-R24A are, for example, the following : C1-C20-alkyl which may be linear or branched, e. g. methyl, ethyl, <BR> <BR> <BR> n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5-to 7-membered cycloalkyl which may in turn bear a C6-C10-aryl group as substitu- ent, e. g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyciododecyl, C2-C20-alkenyi which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e. g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyi, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C6-C2o-aryl which may be substi- tuted by further alkyl groups and/or N-or 0-containing radicals, e. g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5-, or 2, 6-dimethylphenyl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6-or 3, 4, 5-trimethylphenyl, 2-methoxyphenyl, 2-N, N-dimethylaminophenyl, or arylalkyl, which may be substituted by further alkyl groups, e. g. benzyl, o-, m-, p-methylbenzyl, 1-or-2- ethylphenyl, where R23A may also be joined to R24A to form a 5-or 6-membered ring and the or- ganic radical R23A-R24A may also be substituted by halogens such as fluorine, chlorine or bromine.

In organosilicon substituents SiR25A3, the radicals R can be the same radicals described in more detail above for R23A-R24A, where two radicals R25A may also be joined to form a 5-or 6- membered ring, e. g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, triallylsilyl, triphenyl- silyl or dimethylphenylsilyl. Preference is given to using C1-C10-alkyl such as methyl, ethyl, n- propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and also vinyl, allyl, benzyl and

phenyl as radicals R and R. Some of these substituted ligands X are particularly preferably used because they are obtainable from cheap and readily available starting materials. Thus, a particularly preferred embodiment is that in which XA is dimethylamide, methoxide, ethoxide, iso- propoxide, phenoxide, naphthoxide, triflate, p-toluolenesulfonate, acetate or acetylacetonate.

The number n of the ligands XA depends on the oxidation state of the transition metal MA. The number n can therefore not be given in general terms. The oxidation state of the transition metals MA in catalytically active complexes is usually known to those skilled in the art. Chromium, molyb- denum and tungsten are very probably present in the oxidation state +3, vanadium in the oxida- tion state +3 or +4. However, it is also possible to use complexes whose oxidation state does not correspond to that of the active catalyst. Such complexes can then be appropriately reduced or oxidized by means of suitable activators. Preference is given to using chromium complexes in the oxidation state +3 and titanium complexes in the oxidation state 3.

Preferred monocyclopentadienyl complexes A) of this type are 1- (8-quinolyl)-3-phenylcyclopenta- dienylchromium (IIl) dichloride, 1- (8-quinolyl)-3- (1-naphthyl) cyclopentadienylchromium (III) dichlo- ride, 1-(8-quinoly)-3-(4-trifluoromethylphenylcyclopentadienylchro mium(III) dichloride, 1-(8- <BR> <BR> <BR> quinolyl)-3- (4-chlorophenyl) cyclopentadienylchromium (III) dichloride, 1- (8-quinolyl)-2-methyl-3-<BR> <BR> <BR> <BR> <BR> <BR> phenylcyc. opentadienylchromium (ll.) dichloride, 1-(8-quinolyl)-2-methyl-3-(1-naphthyl) cyclopenta-<BR> <BR> <BR> <BR> <BR> <BR> <BR> dienylchromium ( ! ll) dichloride, 1- (8-quinolyl)-2-methyl-3- (4-trifiuoromethylphenyicyclopentadienyl- chromium (III) dichloride, 1-(8-quinoly)-2-methyl-3-(4-chlorophenyl)cyclopentadienylchr omium(III) dichloride, 1- (8-quinolyl)-2-phenylindenylchromium (III) dichloride, 1- (8-quinolyl)-2-phenyl- <BR> <BR> <BR> <BR> benzindenylchromium (III) dichloride, 1- (8- (2-methylquinolyl))-2-methyl-3-phenylcyclopentadienyl- chromium (III) dichloride, 1- (8- (2-methylquinolyl))-2-phenylindenylchromium (III) dichloride, 1- (2- <BR> <BR> <BR> pyridylmethyl)-3-phenylcyclopentadienylchromium (lIl) dichloride, 1- (2-pyridylmethyl)-2-methyl-3-<BR> <BR> <BR> <BR> <BR> <BR> phenylcyclopentadienylchromium (lil) dichloride, 1- (2-quinolylmethyl)-3-phenylcyclopentadienyl- chromium dichloride, 1- (2-pyridylethyl))-3-phenylcyclopentadienylchromium dichloride, 1- (2- pyridyl-1-methylethyl)-3-phenylcyclopentadienylchronium dichloride or 1-(2-pyridyl-1-phenyl- methyl)-3-phenylcyclopentadienylchromium dichloride.

The synthesis of such complexes can be carried out by methods known per se, with preference being given to reacting the appropriately substituted cyclopentadienyl anions with halides of tita- nium, vanadium or chromium. Examples of such preparative methods are described, inter alia, in the Journal of Organometallic Chemistry, 369 (1989), 359-370, and in EP-A-1212333.

We have also found a process for preparing cyciopentadiene systems of the formula (VIa),

where the variables have the following meanings: E'2A-E'6A are each carbon, with four adjacent E'2A-E'6A forming a conjugated diene system and the remaining E'2A-E'6A additionally bearing a hydrogen, R26A-R29A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6- C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon <BR> <BR> 32A 32A 32A 32A 32A 32A<BR> yl part, NR@@@2, N (SIR 3) 2, OR, OSIER 3, BR 2,, SiR 3, where the organic radicals R26A-R29A may also be substituted by halogens and two vicinal radicals R26A-R29A may also be joined to form a five-or six-membered ring, and/or two vicinal radicals R26A-R29A are joined to form a heterocycle which contains at least one atom from the group consisting of N, P, O or S, R30A-R31A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6- C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR32A3, where the organic radicals R30A-R31A may also be substituted by halogens and R30A or R31A and A may also be joined to form a five-or six-membered ring, R32A the radicals. R32A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- C20-alkenyl, C6-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two geminal radicals R32A may also be joined to form a five-or six-membered ring, m is 0,1 or 2, A is an uncharged donor group containing one or more atoms of. group 15 and/or 16 of the Periodic Table of the Elements or a carbene, preferably an unsubstituted, substi- tuted or fused, heteroaromatic ring system, which comprises: a) reacting an (A-(CR29AR30A)m)-- anion with a cyclopentanedione or a silyl ether of an enolised cyclopentanedione.

Possible carboorganic substituents R23A-R3'Aare, for example, the following : C1-C20-alkyl which may be linear or branched, e. g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n- pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5-to 7-membered cycloalkyl which may in turn bear a C6-C10-aryl group as substituent, e. g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C2-C20-alkenyl which may be lin- ear, cyclic or branched and in which the double bond may be internal or terminal, e. g. vinyl, 1- allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyciooctenyl or cyclo- octadienyi, C6-C20-aryl which may be substituted by further alkyl groups and/or N-or 0-containing radicals, e. g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5-, or 2,6- dimethylphenyl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3,4, 5-trimethylphenyl, 2-methoxyphenyl, 2- N, N-dimethylaminophenyl or arylalkyl which may be substituted by further alkyl groups, e. g. ben- zyl, o-, m-, p-methylbenzyl, 1-or 2-ethylphenyl, where two vicinal radicals R26A-R29A and/or R30A and R3'A may also be joined to form a 5-or 6-membered ring and the organic radicals R26A-R31A may also be substituted by halogens such as fluorine, chlorine or bromine. In organosilicon sub- stituents SiR32A3, the radicals R32A can be the same radicals as have been described in more de- tail above for R26A-R31A, where two radicals R32A may also be joined to form a 5-or 6-membered ring, e. g. trimethylsilyl, triethylsilyl, butyldimethylsiiyl, tributyisilyl, triallylsilyl, triphenylsilyl or di- methylphenylsilyl. Furthermore, R26A-R29A can also be amino NR32Ap or N (SiR32A3) 2, alkoxy or aryl- oxy OR32A, for example dimethylamino, N-pyrrolidinyl, picolinyl, methoxy, ethoxy or isopropoxy.

Preference is given to using hydrogen and Cl-Clo-alkyl such as methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, phenyl or benzyl as radicals R26A to R29A Particularly useful radicals R30A to R3'A are hydrogen and Ci-Cio-aikyf such as methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, in particular hydrogen.

The variable A and its preferred embodiments are the same as described further above.

Substituted and unsubstituted 1, 2-cyclopentadiones and 1, 3-cyclopentadiones have been known for a long time and are commercially available. The corresponding silyl ethers of the enolized 1,2- or 1, 3-cyclopentadiones can be prepared, for example, by silylation of 1, 2- or 1,3- cyclopentadiones by means of trialkylsilyl halides or triflates in the presence of catalytic amounts of base (cf. S. Torckleson et al., Synthesis 1976,11, 722-724).

The (A-(CR30AR31A)m)-- anion is an A- anion when m is 0, in which case the negative charge is located on A. When m is 1, it is an (A-CR30AR31A)-- anion in which the negative charge is located on the C atom bearing R 31A and R31A. When m is 2, the (A-(CR30AR31A)m)-- anion is an (A- CR30AR31A -CR30AR31A)-- anion in which the negative charge is located on the carbon atom which bears R30A and R31A and is not bound directly to A. The variables and their preferred embodiments for A, R30A, R3'A and m in these anions are the same as those described above for the cyclopen- tadiene system (VI). The cation associated with the (A-(CR30AR31A)m)-- anion is generally a metal

of group 1 or 2 of the Periodic Table of the Elements which may bear further ligands. Particular preference is given to lithium, sodium or potassium cations which may also bear uncharged ligands such as amines or ethers and the magnesium monochloride or magnesium monobromide cation, which may likewise bear further uncharged ligands.

The negative charge on the anion A'is preferably located on a carbon of A-which is adjacent to a heteroatom of A-, in particular a nitrogen atom if such an atom is present in A-.

The A-anion is usually obtained by metal-halogen exchange of A-halogen with an alkyl metal compound containing C1-C 0-alkyls, in particular C4-alkyls, such as n-butyl and tert-butyl, and a metal of group 1 or 2, in particular lithium, magnesium monochloride or magnesium monobromide cations. Particularly useful alkyl metal compounds are, for example, lithium alkyls, magnesium alkyls, alkylmagnesium halides or mixtures thereof, in particular n-butyllithium and tert- butyllithium. The molar ratio of alkyl metal compound to A-halogen is usually in the range from 0.4 : 1 to 100: 1, preferably in the range from 0.9 : 1 to 10: 1 and particularly preferably from 0.95 : 1 to 1.1 : 1. Examples of such reactions are described by, inter alia, Furukawa et al. in Tet. Lett. 28 (1987), 5845.

The (A-CR30AR3'A)-anion is usually obtained by deprotonation of A-CR30AR3'AH. Strong bases such as lithium alkyls, sodium hydride, sodium amides, sodium alkoxide, sodium alkyls, potas- sium hydride, potassium amides, potassium alkoxide, potassium alkyls, magnesium alkyls, al- kylmagnesium halides or mixtures thereof can be used for this purpose. The molar ratio of base to A-CR30AR3'AH is usually in the range from 0.4 : 1 to 100: 1, preferably in the range from 0.9 : 1 to 10: 1 and particularly preferably from 0.95 : 1 to 1.1 : 1. Examples of such deprotonations are de- scribed in L. Brandsma, Preparative polar organometallic chemistry 2, pp. 133-142.

The (A-CR30AR31A-CR30AR31A)-anion can, for example, be prepared by reacting the correspond- ing halide A-CR30AR31A -(CR30AR31A)-halogen with metallic magnesium. Examples of analogous reactions, which are also referred to as Grignard Reactions, are described, for example, in Or- ganikum, 18'hedition, 1990, p. 499.

The reaction conditions for these reactions are described below.

The reaction product formed in the reaction with the cyclopentadione in step a) is a cyclopente- none-oxy compound which can be worked up in an aqueous medium to form the corresponding alcohol or can, for example, be reacted under acidic conditions to form the corresponding (A- (CR30AR31A) m) ~-substituted cyc. opentenone. The reaction product formed by reaction with a silyl ether of an enolized cyclopentadione in step a) is a cyclopentenoxide silyl ether. Aqueous work-up and dewatering likewise leads to the corresponding (A-(CR30AR3 A) m) ~-substituted cyclopente- none. The further reaction to the cyclopentadiene system (VI) is carried out in a customary fash-

ion by alkylation, arylation or hydride addition onto the cyclopentenone, which is then formed after aqueous work-up and dewatering.

Preference is given to a process for preparing cyclopentadiene systems of the formula (VIb), where the variables have the following meanings: E,2A-E,6A are each carbon, with four adjacent E12A-E13A forming a conjugated diene system and the remaining E12A-E16A additionally bearing a hydrogen, R26A-R28A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6- C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, SiR32A3, where the organic radicals R26A-R23A may also be sub- stituted by halogens and two vicinal radicals R27A-R23A may also be joined to form a five-or six-membered ring, and/or two vicinal radicals R27A-R28A are joined to form a heterocycle which contains at least one atom from the group consisting of N, P, O or S, R30A-R31A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6- C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR 3, where the organic radicals R-R3 may also be substituted by halogens and R30A or R3'A and A may also be joined to form a five-or six-membered ring, R32A the radicals R32A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- C20-a, C6-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two geminal radicals R32A may also be joined to form a five-or six-membered ring, ArylA is C6-C22-aryl, for example phenyl, naphthyl, biphenyl, anthracenyl or phenanthrenyl, which may also be substituted by N-, P-, 0-or S-containing substituents, C1-C22-

alkyl, C2-C22-alkenyl, halogens or haloalkyl or haloaryls having 1-10 carbon atoms *and m is 0 or 1, A is an unsubstituted, substituted or fused, heteroaromatic ring system, which comprises a) reacting an (A-(CR30AR31A)m)-- anion with a cyclopentenone system of the formula (VII) , where the variables are as defined above, to form a cyclopentenone of the formula (VIII) where the variables are as defined above. Furthermore, we have found intermediates of the for- mula (VlII) and cyclopentadienyl systems of the formula (VI).

Possible carboorganic substituents R26A-R3'Aare, for example, the following : C1-C20-alkyl which may be linear or branched, e. g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n- pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5-to 7-membered cycloalkyl which may in turn bear a C6-C10-aryl group as substituent, e. g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C2-C20-alkenyl which may be lin- ear, cyclic or branched and in which the double bond may be internal or terminal, e. g. vinyl, 1- allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or

cyclooctadienyl, C6-C2o-aryl which may be substituted by further alkyl groups and/or N-or O- containing radicals, e. g. phenyl naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2, 4-, 2,5-, or 2, 6-dimethylphenyl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3,4, 5-trimethylphenyl, 2- methoxyphenyl, 2-N, N-dimethylaminophenyl or arylalkyl which may be substituted by further alkyl groups, e. g. benzyl, o-, m-, p-methylbenzyl, 1-or 2-ethylphenyl, where R27A may also be joined to RIIA and/or R30A may be joined to R31A to form a 5-or 6-membered ring and the organic radicals R26A-R31A may also be substituted by halogens such as fluorine, chlorine or bromine. In or- ganosilicon substituents SiR32A3, the radicals R32A can be the same radicals as described further above for R26A-R30A, where two radicals R32A may also be joined to form a 5-or 6-membered ring, e. g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, triallylsilyl, triphenylsilyl or dimethyl- phenylsilyl. Preference is given to using hydrogen and C1-C10-alkyl such as methyl, ethyl, n-pro- pyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl as radicals R to R. Particularly use- ful radicals R30A to R31A are hydrogen and C1-C10-alkyl such as methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, in particular hydrogen.

ArylA is C6-C22-aryl, for example phenyl, naphthyl, biphenyl, anthracenyl or phenanthrenyl, which may also be substituted by N-, P-, O-or S-containing substituents, C-C22-a, C2-C22-alkenyl, halogens or haloalkyls or haloaryis having 1-10 carbon atoms, for example o-, m-, p- methylphenyl, 2,3-, 2,4-, 2, 5-, or 2, 6-dimethylphenyl, 2,3, 4-, 2,3, 5-, 2, 3,6-, 2,4, 5-, 2,4, 6- or 3,4, 5- trimethylphenyl, o-, m-, p-dimethylaminophenyl, o-, m-, p-methoxyphenyl, o-, m-, p-fluorophenyl, o-, m-, p-chlorophenyl, o-, m-, p-trifluoromethylphenyl, 2,3-, 2,4-, 2, 5- or 2, 6-difluorophenyl, 2,3-, 2,4-, 2, 5- or 2, 6-dichlorophenyl or 2,3-, 2,4-, 2, 5- or 2, 6-di (trifluoromethyl) phenyl.

A is an unsubstituted, substituted or fused heteroaromatic ring system which may contain het- eroatoms from the group consisting of oxygen, sulfur, nitrogen and phosphorus in addition to car- bon ring atoms. Examples of 5-membered heteroaryl groups, which may contain from one to four nitrogen atoms or from one to three nitrogen atoms and/or one sulfur or oxygen atom as ring at- oms in addition to carbon atoms are 2-furyl, 2-thienyl, 2-pyrrolyl, 3-isoxazolyl, 5-isoxazolyl, 3- isothiazolyl, 5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazoly), 4-imidazolyi, 5-imidazolyl, 1, 2, 4-oxadiazol-3-yl, 1,2, 4-oxadiazol-5-yl, 1, 3, 4-oxadiazol-2-yl or 1,2, 4-triazol-3-yl. Examples of 6-membered heteroaryl groups which may contain from one to four nitrogen atoms and/or a phosphorus atom are 2-pyridinyl, 2-phosphaphenyl, 3-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 2-pyrazinyl, 1, 3,5-triazin- 1-yl and 1,2, 4-triazin-3-yl, 1,2, 4-triazin-5-yl or 1,2, 4-triazin-6-y.. The 5-membered and 6-membered heteroaryl groups may also be substituted by C1-C10-alkyl, C6-C10-alkyl, alkylaryl hav- ing from 1 to 10 carbon atoms in the alkyl part and 6-10 carbon atoms in the aryl part, trialkylsilyl or halogens such as fluorine, chlorine or bromine or be fused with one or more aromatics or het- eroaromatics. Examples of benzo-fused 5-membered heteroaryl groups are 2-indolyl, 7-indolyl, 2-coumaronyl, 7-coumaronyl, 2-thianaphthenyl, 7-thianaphthenyl, 3-indazolyl, 7-indazolyl, 2-benzimidazolyl and 7-benzimidazolyl. Examples of benzo-fused 6-membered heteroaryl groups

are 2-quinolyl, 8-quinolyl, 3-cinnolyl, 8-cinnolyl, 1-phthalazyl, 2-quinazoiyl, 4-quinazolyl, 8-quinazolyl, 5-quinoxalyl, 4-acridyl, 1-phenanthridyl and 1-phenazyl. Naming and numbering of the heterocycles has been taken from L. Fieser and M. Fieser, Lehrbuch der or-ganischen Che- mie, 3rd revised edition, Verlag Chemie, Weinheim 1957.

Among these heteroaromatic systems A, particular preference is given to unsubstituted, substi- tuted and/or fused six-membered heteroaromatics having 1,2, 3,4 or 5 nitrogen atoms in the heteroaromatic part, in particular substituted and unsubstituted 2-pyridyl, 2-quinolyl or 8-quinolyl.

A is therefore preferably a group of the formula (IV) , where E-E are each, independently of one another, carbon or nitrogen, R16A-R21A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6-C20- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR22A3, where the organic radicals R'6A-R21A may also be substituted by halogens or nitrogen and further C1-C20-alkyl, C2-C2o-alkenyl, C6-C2o-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR22A3 groups and two vicinal radicals R'6A-R21A or R16A and Z may also be joined to form a five-or six-membered ring and R22A the radicals R22A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- C20-alkenyl, C6-C2o-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R22A may also be joined to form a five-or six-membered ring and p is 0 when E6A-E11A is nitrogen and is 1 when E6A-E11A is carbon.

In particular, 0 or 1 of E5A-E"A is nitrogen and the remainder carbon. A is particularly preferably 2- pyridyl, 6-methyl-2-pyridyl, 4-methyl-2-pyridyl, 5-methyl-2-pyridyl, 5-ethyl-2-pyridyl, 4, 6-dimethyl-2- pyridyl, 3-pyridazyl, 4-pyrimidyl, 6-methyl-4-pyrimidyl, 2-pyrazinyl, 6-methyl-2-pyrazinyl, 5-methyl- 2-pyrazinyl, 3-methyl-2-pyrazinyl, 3-ethylpyrazinyi, 3,5, 6-trimethyl-2-pyrazinyl, 2-quinolyl, 4-

methyl-2-quinolyl, 6-methyl-2-quinolyl, 7-methyl-2-quinolyl, 2-quinoxalyl, 3-methyl-2-quinoxalyi or 8-quinolyl. m is 0 or 1, in particular, m is 0 when A is a donor of the formula (1Vb) and is 1 when A is a donor of the formula (IVa) Cyclopentenones of the formula (VII) have been known for a long time and can be prepared, for example, by silylation of 1, 3-cyclopentadiones by means of trialkylsilyl halides or triflates in the presence of catalytic amounts of base (cf. S. Torckleson et al., Synthesis 1976,11, 722-724).

The (A-(CR30AR31A) m)-anion is an A-anion when m is 0 and when m is 1 is an (A-CR29AR30A)-- anion. The variables and their preferred embodiments for A, R29A, R30A and m in these anions are the same as described above for the cyclopentadiene system (VI). The cation associated with the (A-(CR29AR30A)m)-- anion is generally a metal of group 1 or 2 of the Periodic Table of the Elements which may bear further ligands. Particular preference is given to lithium, sodium or potassium cations which may also bear uncharged ligands such as amines or ethers and the magnesium monochloride or magnesium monobromide cation which may likewise bear further uncharged ligands.

The negative charge on the anion A-is preferably located on a carbon of A-adjacent to a heteroa- tom of A', in particular a nitrogen atom if such an atom is present in A-. A-is preferably 2-furyl, 2- thienyl, 2-pyrrolyl, 3-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl, 5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 5-pyrazolyi, 2-oxazolyi, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl, 4- imidazolyl, 5-imidazolyl, 1, 2, 4-oxadiazol-3-yl, 1,2, 4-oxadiazol-5-yl, 1,3, 4-oxadiazol-2-yl or 1,2, 4- triazol-3-yl, 2-pyridinyl, 2-phosphabenzolyl, 3-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 2-pyrazinyl, 1,3, 5-triazin-2-yl, 1, 2, 4-triazin-3-yt, 1,2, 4-triazin-5-yl, 1, 2, 4-triazin-6-yl, 2-indolyl, 7-indolyl, 2- coumaronyl, 7-coumaronyl, 2-thianaphthenyl, 7-thianaphthenyl, 3-indazolyl, 7-indazolyl, 2- benzimidazolyl or 7-benzimidazolyl, 2-quinolyl, 8-quinolyl, 3-cinnolyl, 8-cinnolyl, 1-phthalazyl, 2- quinazolyl, 4-quinazolyl, 8-quinazoiyl, 5-quinoxalyl, 4-acridyl, 1-phenanthridyl or 1-phenazyl.

In the (A-CR29AR30A)--anion, the-CR29AR30A-group bears the negative charge. This group is preferably located in the ortho position rotative to a heteroatom of A, in particular a nitrogen atom if such an atom is present in A.

The (A-(CR29AR30Å) m)-anion is preferably a group of the formula (IXa) (m=1) or of the formula (IXb) (m=O) :

, where E6A-E11A are each,, independently of one another, carbon or nitrogen, R16A-R21A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6-C20- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR22A3, where the organic radicals R16A-R21A may also be substituted by halogens or nitrogen and further C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR22A3 groups and two vicinal radicals R15A-R21A or R16A and Z may also be joined to form a five-or six-membered ring and R22A the radicals R22A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- C2o-alkenyl, C6-C2O-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R 22A may also be joined to form a five-or six-membered ring and R29A-R30A are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6- C20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR 3, where the organic radicals R29A-R30A may also be substituted by halogens and R29A or R30A and A may also be joined to form a five-or six-membered ring, R31A the radicals R3'A are each, independently of one another, hydrogen, C1-C20-alkyl, C2- C20-alkenyl, C6-C2o-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two geminal radicals R31A may also be joined to form a five-or six-membered ring and p is 0 when E6A-E11A is nitrogen and is 1 when E6A-E11A is carbon.

In particular, 0 or 1 of E6A-E11A is nitrogen and the remainder are carbon. Particularly preferred A-- systems (iXb) are substituted and unsubstituted 8-quinolyl.

The A-anion is usually obtained by metal-halogen exchange of A-halogen with an alkyl metal compound c6ntaining Cl-Clo-alkyls, in particular C4-alkyls, such as n-butyl and tert-butyl, and a metal of group 1 or 2, in particular lithium, magnesium monochloride or magnesium monobromide cations. Particularly useful alkyl metal compounds are, for example, lithium alkyls, magnesium alkyls, alkylmagnesium halides or mixtures thereof, in particular n-butyllithium and tert- butyllithium. The molar ratio of alkyl metal compound to A-halogen is usually in the range from 0.4 : 1 to 100: 1, preferably in the range from 0.9 : 1 to 10: 1 and particularly preferably from 0. 95 : 1 to 1.1 : 1. Exampies of such reactions are described by, inter alia, Furukawa et al. in Tet. Lett. 28 (1987), 5845.

The (A-CR30AR31A\ _-anion is usually obtained by deprotonation of A-CR30AR31AH. Strong bases such as lithium alkyls, sodium hydride, sodium amides, sodium alkoxide, sodium alkyls, potas- sium hydride, potassium amides, potassium alkoxide, potassium alkyls, magnesium alkyls, al- kylmagnesium halides or mixtures thereof can be used for this purpose. The molar ratio of base to A-CR30AR31AH is usually in the range from 0.4 : 1 to 100: 1, preferably in the range from 0.9 : 1 to 10: 1 and particularly preferably from 0.95 : 1 to 1.1 : 1. Examples of such deprotonations are de- scribed in L. Brandsma, Preparative polar organometallic chemistry 2, pp. 133-142.

A-CR33AR31AH is preferably 2-methylfuran, 2, 5-dimethylfuran, 2-ethylfuran, 1, 2-dimethylpyrrole, 1,2, 3-trimethylpyrrole, 1, 3-dimethylpyrazole,. 1, 2-dimethylimidazole, 1-decyl-2-methylimidazole, 1- methyl-2-undecylimidazole, 2-picoline, 2-ethylpyridine, 2-propylpyridine, 2-benzylpyridine, 2,6- lutidine, 2, 4-lutidine, 2, 5-lutidine, 2, 3-cycloheptenopyridine, 5-ethyl-2-methylpyridine, 2,4, 6- collidine, 3-methylpyridazine, 4-methylpyrimidine, 4, 6-dimethylpyrimidine, 2-methylpyrazine, 2- ethylpyrazine, 2, 6-dimethylpyrazine, 2, 5-dimethylpyrazine, 2, 3-dimethylpyrazine, 2,3- diethylpyrazine, tetrahydroquinoxaline, tetramethylpyrazine, quinaldine, 2, 4-dimethylquinoline, 2, 6-dimethylquinoline, 2, 7-dimethylquinoline, 2-methylquinoxaline, 2, 3-dimethylquinoxaline or neocuproin.

As solvents in the metal-halogen exchange step and in the deprotonation step, it is possible to use all aprotic solvents, in particular aliphatic and aromatic hydrocarbons such as n-pentane, n- hexane, isohexane, n-heptane, isoheptane, decalin, benzene, toluene, ethylbenzene or xylene or ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dimethoxyethane or diethylene glycol dimethyl ether and mixtures thereof. The reactions can be carried out at from-100 to +160°C, in particular from-80 to 100°C. At temperatures above 40°C, preference is given to using aromatic or aliphatic solvents which contain no ethers or contain only a small proportion of ethers.

The (A-(CR30AR31A)m)- anion formed after metal-halogen exchange or deprotonation can be iso- lated or preferably reacted without further isolation with the cyclopentenone (VII). As solvents for the further reaction, it is possible to use all aprotic solvents, in particular aliphatic and aromatic hydrocarbons such as n-pentane, n-hexane, isohexane, n-heptane, isoheptane, decalin, benzene,

toluene, ethylbenzene or xylene or ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dimethoxyethane or diethylene glycol dimethyl ether and mixtures thereof. The reaction can be carried out at from-100 to +160°C, preferably from-80 to 100°C and particularly preferably from 0 to 60°C. At temperatures above 40°C, preference is given to using aromatic or aliphatic solvents which contain no ethers or only small proportion of ethers.

The cyclopentenone of the formula (VIII) formed in step a) is then reacted further with an aryl anion (ArylA) in a subsequent step b). The aryl anion has a metal cation as countercation. This is generally a metal of group 1 or 2 of the Periodic Table of the Elements which may bear further ligands. Particular preference is given to lithium, sodium or potassium cations which may also bear uncharged ligands such as amines or ethers and the magnesium monochloride or magne- sium monobromide cation which may likewise bear further uncharged ligands, in particular lithium, magnesium monochloride or magnesium monobromide cations.

(ArylA) is formally a C6-C22-aryl such as phenyl, naphthyl, biphenyl, anthracenyl or phenanthrenyl which is deprotonated on the aromatic ring. The aryl may be substituted by N-, P-, O- or S- containing substituents, C-C22-alkyl, C2-C22-alkenyl, halogens or haloalkyl or haloaryls having 1- 10 carbon atoms, for example o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5-, or 2, 6-dimethylphenyl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3,4, 5-trimethylphenyl, o-, m-, p-dimethylaminophenyf, o-, m- , p-dimethylphosphinophenyl, o-, m-, p-diphenylphosphinophenyl o-, m-, p-methoxyphenyl, o-, m-, p-fluorophenyl, o-, m-, p-chlorophenyl, o-, m-, p-trifluoromethylphenyl, 2,3-, 2,4-, 2,5-, or 2,6- difluorophenyl, 2, 3-, 2,4-, 2,5-, or 2, 6-dichlorophenyl or 2,3-, 2,4-, 2, 5- or 2, 6-di (trifluoromethyl)- phenyl deprotionated on the aromatic ring.

The (ArylA) ~ anion is usually obtained by metal-halogen exchange of ArylA-halogen with an alkyl metal compound containing C,-C10-alkyls, in particular C4-alkyls, such as n-butyl and tert-butyl, and a metal of-group 1 or 2, in particular lithium, magnesium monochloride or magnesium mono- bromide cations. Particularly useful alkyl metal compounds are, for example, lithium alkyls, mag- nesium alkyls, alkylmagnesium halides or mixtures thereof, in particular n-butyllithium and tert- butyllithium. The molar ratio of alkyl metal compound to ArylA-halogen is usually in the range from 0.4 : 1 to 100: 1, preferably in the range from 0.9 : 1 to 10: 1 and particularly preferably from 0.95 : 1 to 1.1 : 1. Examples of such reactions are described by, inter alia, Furukawa et al. in Tet. Lett. 28 (1987), 5845. The arylanion is associated with the metal cation from this step as cation.

Solvents and reaction temperatures suitable for this metal-halogen exchange step are the same ones as described above for the metal-halogen exchange of A-halogen. Many aryl anions are also commercially available.

The aryl anion formed after metal-halogen exchange can be isolated or preferably reacted without further isolation with the cyclopentenone (Vll.). As solvents for the further reaction, it is possible to

use all aprotic solvents, in particular aliphatic and aromatic hydrocarbons such as n-pentane, n- hexane, isohexane, n-heptane, isoheptane, decalin, bezene, toluene, ethylbenzene or xylene or ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dimethoxyethane or diethylene glycol dimethyl ether and mixtures thereof. The reaction can be carried out at from-100 to +160°C, pref- erably from-80 to 100°C and particularly preferably from 0 to 60°C. At temperatures above 40°C, preference is given to using aromatic or aliphatic solvents which contain no ethers or only small proportions of ethers.

The cyclopentenoxide formed by reaction of the aryl anion with the cyclopentenone (VIII) in step b) is usually protonated before dewatering. This can be achieved, for example, by means of small amounts of acid, for example HCI, or by means of aqueous work-up. The intermediate obtained in this way, a cyclopentenol, is susbsequently dehydrated to form the cyclopentadiene system (Vlb). This is often carried out with addition of catalytic amounts of acid such as HCI or p-toluenesulfonic acid or iodine. Dewatering can be carried out at from-10 to +160°C, preferably from 0 to 100°C and particularly preferably from 20 to 80°C. As solvents, it is possible to use, for example, aprotic solvents, in particular alipahtic and aromatic hydrocarbons such as n-pentane, n-hexane, isohex- ane, n-heptane, isoheptane, decalin, benzene, toluene, ethylbenzene or xylene or ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dimethoxyethane or diethylene glycol dimethyl ether and mixtures thereof. Toluene and heptane are particularly useful. Water separators are often also used for dewatering.

The cyclopentenone (ViIl) can also be reacted with an alkyl anion having from 1 to 20 carbon atoms. However, this leads, after dewatering, to a cyclopentadiene product (VI) in which aryl is replaced by alkyd.

The cyclopentadiene system (Via) or (Vlb) obtained in this way can then be deprotonated by cus- tomary methods, for example by means of potassium hydride or n-butyllithium, and reacted fur- ther with the appropriate transition metal compound, e. g. chromium trichloride tris (tetrahydrofuran), to form the corresponding monocyclopentadienyl complex (A). Furthermore, the cyclopentadiene system (Via) or (Vlb) can also be reacted directly with, for example, chro- mium amides to form the monocyclopentadienyl complex (A) in a manner analogous to the proc- ess in EP-A-742 046.

This method of preparing the cyclopentadiene systems (VI) is particularly advantageous since it uses simple starting materials and gives good yieids. The (A-(CR30AR3'A) m)-anion is a very bulky nucleophile. It can therefore be introduced more readily by means of a Michael addition. If the aryl or alkyl is introduced first and the bulky (A-(CR30AR31A)m)- anion is introduced subsequently, eno- lizations frequently occur as secondary reactions.

The monocyclopentadienyl complexes of the present invention can be used alone or together with further components as catalyst system for olefin polymerization. We have also found catalyst systems for olefin polymerization comprising A) at least one monocyclopentadienyl complex according to the present invention, B) optionally an organic or inorganic support, C) optionally one or more activating compounds, D) optionally one or more catalysts suitable for olefin polymerization and E) optionally one or more metal compounds containing a metal of group 1,2 or 13 of the Peri- odic Table.

Thus, more than one of the monocyclopentadienyl complexes of the present invention can simul- taneously be brought into contact with the olefin or olefins to be polymerized. This has the advan- tage that a wide range of polymers can be produced in this way. For example, bimodal products can be prepared in this way.

For the monocyclopentadienyl complexes of the present invention to be able to be used in polym- erization processes in the gas phase or in suspension, it is often advantageous for them to be used in the form of a solid, i. e. for them to be applied to a solid support B). Furthermore, the sup- ported monocyclopentadienyl complexes have a high productivity. Consequently, the mono- cyclopentadienyl complexes of the present invention can, if desired, also be immobilized on an organic or inorganic support B) and be used in supported form in the polymerization. This en- ables, for example, deposits in the reactor to be avoided and the polymer morphology to be con- trolled. As support materials, preference is given to using silica gel, magnesium chloride, alumi- num oxide, mesoporus materials, aluminosilicates, hydrotalcites and organic polymers such as polyethylene, polypropylene, polystyrene, polytetrafluoroethylene or polymers bearing polar func- tional groups, for example copolymers of ethene and acrylic esters, acrolein or vinyl acetate.

Particular preference is given to a catalyst system comprising a monocyclopentadienyl complex according to the present invention and at least one activating compound C) together with a sup- port component B).

To obtain such a supported catalyst system, the unsupported catalyst system can be reacted with a support component B). The order in which support component B), monocyclopentadienyl com- plex A) according to the present invention and the activating compound C) is in principle immate- rial. The monocyclopentadienyl complex A) of the present invention and the activating compound

C) can be immobilized independently of one another or simultaneously. After the individual proc- ess steps, the solid can be washed with suitable inert solvents, e. g. aliphatic or aromatic hydro- carbons.

In a preferred method of preparing the supported catalyst system, at least one of the mono- cyclopentadienyl complexes of the present invention is brought into contact with at least one acti- vating compound C) in a suitable solvent, preferably giving a soluble reaction product, an adduct or a mixture. The preparation obtained in this way is then mixed with the dehydrated or passivated support material, the solvent is removed and the resulting supported monocyclopentadienyl cata- lyst system is dried to ensure that all or most of the solvent is removed from the pores of the sup- port material. The supported catalyst is obtained as a free-flowing powder. Examples of the indus- trial implementation of the above process are described in WO 96/00243, WO 98/40419 or WO 00/05277. In a further preferred embodiment, the activating compound C) is applied to the support component B) first and this supported compound is subsequently brought into contact with the monocyclopentadienyl complex A) of the present invention.

As support component B), preference is given to using finely divided supports which can be any organic or inorganic solid. In particular, the support component B) can be a porous support such as talc, a sheet silicate such as montmorillonite, mica, an inorganic oxide or a finely divided poly- mer powder (e. g. polyolefin or a polymer bearing'polar functional groups).

The support materials used preferably have a specific surface area in the range from 10 to 1000 m2/g, a pore volume in the range from 0.1 to 5 ml/g and a mean particle size of 1 to 500 p. m.

Preference is given to supports having a specific surface. area in the range from 50 to 700 m2/g, a pore volume in the range from 0.4 to 3.5 mug and a mean particle size in the range from 5 to 350 p. m. Particutar preference is given to supports having a specific surface area in the range from 200 to 550 m2/g, a pore volume in the range from 0.5 to 3.0 mi/g and a mean particle size of from 10 to 150 um.

The inorganic support can be subjected to a thermal treatment, e. g. to remove adsorbed water.

Such a drying treatment is generally carried out at from 80 to 800°C, preferably from 100 to 300°C, with drying at from 100 to 200°C preferably being carried out under reduced pressure and/or under a blanket of inert gas (e. g. nitrogen), or the inorganic support can be calcined at from 200 to 1 000°C to produce the desired structure of the solid and/or set the desired OH con- centration on the surface. The support can also be treated chemically using customary desiccants such as metal alkyl, preferably aluminum alkyls, chlorosilanes or SiC14, or else methylaluminox- ane. Appropriate treatment methods are described, for example, in WO 00/31090.

The inorganic support material can also be chemically modified. For example, treatment of silica gel with NH4SiF6 or other fluorinating agents leads to fluorination of the silica gel surface, or

treatment of silica gels with silanes containing nitrogen-, fluorine-or sulfur-containing groups leads to correspondingly modified silica gel surfaces.

Organic support materials such as finely divided polyolefin powders (e. g. polyethylene, polypro- pylene or polystyrene) can also be used and are preferably likewise freed of adhering moisture, solvent residues or other impurities by appropriate purification and drying operations before use. It is also possible to use functionalized polymer supports, e. g. ones based on polystyrene, polyeth- ylene or polypropylene, via whose functional groups, for example ammonium or hydroxy groups, at least one of the catalyst components can be fixed.

Inorganic oxides suitable as support component B) may be found among the oxides of elements of groups 2,3, 4,5, 13,14, 15 and 16 of the Periodic Table of the Elements. Examples of oxides preferred as supports include silicon dioxide, aluminum oxide and mixed oxides of the elements calcium, aluminum, silicon, magnesium or titanium and also corresponding oxide mixtures. Other inorganic oxides which can be used alone or in combination with the abovementioned preferred oxidic supports are, for example, MgO, CaO, AIPO4, ZrO2, TiO2, B203 or mixtures thereof.

As solid support materials B) for catalysts for olefin polymerization, preference is given to using silica gels since particles whose size and structure make them suitable as supports for olefin po- lymerization can be produced from this material. Spray-dried silica gels comprising spherical ag- glomerates of smaller granular particles, i. e. primary particles, have been found to be particularly useful. These silica gels can be dried and/or calcined before use.

Further preferred supports B) are hydrotalcites and calcined hydrotalcites. In mineralogy, hydro- talcite is a natural mineral having the ideal formula Mg6AI2 (OH) 16CO3 4H20 whose structure is derived from that of brucite Mg (OH) 2. Brucite crystallizes in a sheet structure with the metal ions in octahedral holes between two layers of close-packed hydroxy. ions, with only every second layer of the octahedral holes being occupied. In hydrotalcite, some magnesium ions are replaced by aluminum ions, as a result of which the packet of layers gains a positive charge. This is compensated by the anions which are located together with water of crystallization in the layers in between.

Such sheet structures are found not only in magnesium-aluminum hydroxides, but also generally in mixed metal hydroxides of the formula M (ii) 2x2+M (1ll) 23+ (0H) 4x+4 A2/nn ZH20

which have a sheet structure and in which M (II) is a divalent metal such as Mg, Zn, Cu, Ni, Co, Mn, Ca and/or Fe and M (III) is a trivalent metal such as Al, Fe, Co, Mn, La, Ce and/or Cr, x is from 0.5 to 10 in steps of 0. 5, A is an interstitial anion and n is the charge on the interstitial anion which can be from 1 to 8, usually from 1 to 4, and z is an integer from 1 to 6, in particular from 2 to 4.

Possible interstitial anions are organic anions such as alkoxide anions, alkyl ether sulfates, aryl ether sulfates or glycol ether sulfates, inorganic anions such as, in particular, carbonate, hydro- gencarbonate, nitrate, chloride, sulfate or B (OH) 4 or polyoxo metal anions such as Mo70246~ or V10028 6-. However, a mixture of a plurality of such anions can also be present.

Accordingly, all such mixed metal hydroxides having a sheet structure should be regarded as hydrotalcites for the purposes of the present invention.

Calcined hydrotalcites can be prepared from hydrotalcites by calcination, i. e. heating, by means of which, inter alia, the desired hydroxyl group content can be set. In addition, the crystal structure also changes. The preparation of the calcined hydrotalcites used according to the present inven- tion is usually carried out at temperatures above 180°C. Preference is given to calcination for from 3 to 24 hours at from 250°C to 1 000°C, in particular from 400°C to 700'C. It is possible for air or inert gas to be passed over the solid during calcination or for a vacuum to be applied.

On heating, the natural or synthetic hydrotaicites firstly give off water, i. e. drying occurs. On fur- ther heating, the actual calcination, the metal hydroxides are converted into the metal oxides by elimination of hydroxyl groups and interstitial anions; OH groups or interstitial anions such as car- bonate can also still be present in the calcined hydrotalcites. A measure of this is the loss on igni- tion. This is the weight loss experienced by a sample which is heated in two steps firstly for 30 minutes at 200°C in a drying oven and then for 1 hour at 950°C in a muffle furnace.

The calcined hydrotalcites used as component B) are thus mixed oxides of the divalent and triva- lent metals M ( ! I) and M (III), with the molar ratio of M (li) to M (III) generally being in the range from 0.5 to 10, preferably from 0.75 to 8 and in particular from 1 to 4. Furthermore, normal amounts of impurities, for example Si, Fe, Na, Ca or Ti and also chlorides and sulfates, can also be present.

Preferred calcined hydrotalcites B) are mixed oxides in which M (li) is magnesium and M (III) is aluminum. Such aluminum-magnesium mixed oxides are obtainable from Condea Chemie GmbH (now Sasol Chemie), Hamburg, under the trade name Puralox Mg.

Preference is also given to calcined hydrotaicites in which the structural transformation is com- plete or virtually complete. Calcination, i. e. transformation of the structure, can be confirmed, for example, by means of X-ray diffraction patterns.

The hydrotalcites, calcined hydrotalcites or silica gels employed are generally used as finely di- vided powders having a mean particle diameter d5o of from 5 to 200 µm, preferably from 10 to 150 µm, particularly preferably from 15 to 100 m and in particular from 20 to 70 , m, and usually have pore volumes of from 0.1 to 10 cm3/g, preferably from 0.2 to 5 cm3/g, and specific surface areas of from. 30 to 1 000 m2/g, preferably from 50 to 800 m2/g and in particular from 100 to 600 m2/g. The monocyclopentadienyl complexes of the present invention are preferably applied in such an amount that the concentration of transition metal complexes in the finished catalyst sys- tem is from 5 to 200 µmol, preferably from 20 to 100 µmol and particularly preferably from 25 to 70 limo. per g of support B).

Some of the monocyclopentadienyl complexes of the present invention have little polymerization activity on their own and are then brought into contact with an activator, viz. the component C), to be able to display good polymerization activity. For this reason, the catalyst system optionally further comprises, as component C), one or more activating compounds, preferably at least one cation-forming compound C).

Suitable compounds C) which are able to react with the monocyclopentadienyl complex A) to convert it into a catalytically active, or more active, compound are, for example, compounds such as an aiuminoxane, a strong uncharged Lewis acid, an ionic compound having a Lewis-acid cation or an ionic compound containing a Brönsted acid as cation.

As aluminoxanes, it is possible to use, for example, the compounds described in WO 00/31090.

Particularly useful aluminoxanes are open-chain or cyclic aluminoxane compounds of the for- mula (X) or (XI) where R'c-R 4C are each, independently of one another, a Cl-C6-alkyl group, preferably a methyl, ethyl, butyl or isobutyl group, and I is an integer from 1 to 30, prefera- bly from 5 to 25.

A particularly useful aluminoxane compound is methylaluminoxane.

These oligomeric aluminoxane compounds are usually prepared by controlled reaction of a solu- tion of trialkylaluminum with water. In general, the oligomeric aluminoxane compounds obtained in this way are in the form of mixtures of both linear and cyclic chain molecules of various lengths, so that I is to be regarded as a mean. The aluminoxane compounds can also be present in admix- ture with other metal alkyls, usually aluminum alkyls. Aluminoxane preparations suitable as com- ponent C) are commercially available.

Furthermore, modified aluminoxanes in which some of the hydrocarbon radicals have been re- placed by hydrogen atoms or alkoxy, aryloxy, siloxy or amide radicals can also be used as com- ponent C) in place of the aluminoxane compounds of the formula (X) or (XI).

It has been found to be advantageous to use the monocyclopentadienyl complexes A) and the aluminoxane compounds in such amounts that the atomic ratio of aluminum from the aluminoxane compounds including any aluminum alkyl still present to the transition metal from the mono- cyclopentadienyl complex A) is in the range from 1: 1 to 1 000: 1, preferably from 10: 1, to 500: 1 and in particular in the range from 20: 1 to 400: 1.

A further class of suitable activating components C) are hydroxyaluminoxanes. These can be prepared, for example, by addition of from 0.5 to 1.2 equivalents of water, preferably from 0.8 to 1.2 equivalents of water, per equivalent of aluminum to an alkylaluminum compound, in particular triisobutylaluminum, at low temperatures, usually below 0°C. Such compounds and their use in olefin polymerization are described, for example, in WO 00/24787. The atomic ratio of aluminum from the hydroxyaluminoxane compound to the transition metal from the monocyclopentadienyl complex A) is usually in the range from 1 : 1 to 100: 1, preferably from 10: 1 to 50: 1 and in particular in the range from 20: 1 to 40: 1. Preference is in this case given to using a monocyclopentadienyl metal dialkyl compound A).

As strong, uncharged Lewis acids, preference is given to compounds of the formula (Xll) M1CX1CX2CX3C (XII) where mic is an element of group 13 of the Periodic Table of the Elements, in par- ticular B, Al or Ga, preferably B, X1C, x2c and X3C are each hydrogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl, arylalkyl, haloal- kyl or haloaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical or fluorine, chlorine, bromine or iodine, in particular haloaryls, preferably pentafluorophenyl.

Further examples of strong, uncharged Lewis acids are given in WO 00/31090.

Compounds, of this type which are particularly useful as component C) are boranes and boroxins such as trialkylborane, triarylborane or trimethylboroxin. Particular preference is given to using boranes which bear at least two perf) uorinated aryl radicals. Particular preference is given to compounds of the formula (XII) in which X1C, X2C and X3C are identical, preferably tris (pentafluorophenyl) borane.

Suitable compounds C) are preferably prepared by reaction of aluminum or boron compounds of the formula (XII) with water, alcohols, phenol derivatives, thiophenol derivatives or aniline deriva- tives, with halogenated and especially perfluorinated alcohols and phenois being of particular importance. Examples of particularly useful compounds are pentafluorophenol, 1,1- bis (pentafluorophenyl) methanol and 4-hydroxy-2,2', 3,3', 4,4', 5,5', 6, 6'-nonafluorobiphenyl. Exam- pies of combinations of compounds of the formula (XI !) with Brönsted acids are, in particular, trimethylaluminum/pentafluorophenol, trimethylaluminum/1-bis (pentafluorophenyl) methanol, trimethylaluminum/4-hydroxy-2, 2', 3,3', 4,4', 5,5', 6, 6'-nonafluorobiphenyl, triethylalumi- num/pentafluorophenol and triisobutylaluminum/pentafiuorophenol and triethylaluminuml4, 4'- dihydroxy-2,2', 3,3', 5,5', 6, 6'-octafluorobiphenyl hydrate.

In further suitable aluminum and boron compounds of the formula (XII), X'c is an OH group. Ex- amples of compounds of this type are boronic acids and borinic acids, in particular borinic acids having perfluorinated aryl radicals, for example (C6F5)2BOH.

Strong uncharged Lewis acids suitable as activating compounds C) also include the reaction products of a boronic acid with two equivalents of an aluminum trialkyl or the reaction products of an aluminum trialkyl with two equivalents of an acidic fluorinated, in particular perfluorinated, hy- drocarbon compound such as pentafluorophenol or bis (pentafluorophenyl) borinic acid.

Suitable ionic compounds having Lewis acid cations include salt-like compounds of the cation of the formula (XIII) [((M2C)a+)Q1Q2... Qz]d+ (XIII) where M2C is an element of groups 1 to 16 of the Periodic Table of the Elements, Q, to Qz are singly negatively charged groups such as C1-C28-alkyl, C6-C15-aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl each having from 6 to 20 carbon at- oms in the aryl radical and from 1 to 28 carbon atoms in the alkyl radical, Cs-Cio-cycloalkyl which may bear C1-C10-alkyl groups as substituents,

halogen, C1-C2a-alkoxy, C6-C5-aryloxy, silyl or mercaptyl groups, zu a is an integer from 1 to 6 and z is an integer from 0 to 5, d corresponds to the difference a-z, but d is greater than or equal to 1.

Particularly useful cations are carbonium cations, oxonium cations and sulfonium cations and also cationic transition meta ! complexes. Particular mention may be made of the triphenylmethyl cation, the silver cation and the 1, 1'-dimethylferrocenyl cation. They preferably have noncoordi- nating counterions, in particular boron compounds as are also mentioned in WO 91/09882, pref- erably tetrakis (pentafluorophenyl) borate.

Salts having noncoordinating anions can also be prepared by combining a boron or aluminum compound, e. g. an aluminum alkyl, with a second compound which can react to link two or more boron or aluminum atoms, e. g. water, and a third compound which forms an ionizing ionic com- pound with the boron or aluminum compound, e. g. triphenylchloromethane, or optionally a base, preferably an organic nitrogen-containing base, for example an amine, an aniline derivative or a nitrogen heterocycle. In addition, a fourth compound which likewise reacts with the boron or alu- minum compound, e. g. pentafluoropheno., can be added.

Ionic compounds containing Brönsted acids as cations preferably likewise have noncoordinating counterions. As Brönsted acid, particular preference is given to protonated amine or aniline de- rivatives. Preferred cations are N, N-dimethylanilinium, N, N-dimethylcyclohexylammonium and N, N-dimethylbenzylammonium and also derivatives of the latter two.

Compounds containing anionic boron heterocycles as are described in WO 9736937 are also suitable as component C), in particular dimethylanilinium boratabenzene or trityl boratabenzene.

Preferred ionic compounds C) contain borates which bear at least two perfluorinated aryl radicals.

Particular preference is given to N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate and in particular N, N-dimethylcyclohexylammonium tetrakis (pentafluorophenyl) borate, N, N-dimethy. benzylammonium tetrakis (pentafluorophenyl) borate or trityl tetrakispentafluoro- pheny, borate.

It is also possible for two or more borate anions and/or boranes to be joined to one another or for a borate anion to be joined to a borane, as in the dianion [ (C6F5) 3B-CeF4-B (C6F5) 3' or the anion [(C6F5) 3B-CN-B (C6Fs) 3]-, or the borate anion can be bound via a bridge bearing a suitable func- tional group to the support surface.

Further suitable activating compounds C) are listed in WO 00/31090.

The amount of strong, uncharged Lewis acids, ionic compounds having Lewis-acid cations or ionic compounds containing Brönsted acids as cations is preferably from 0. 1 to 20 equivalents, more preferably from 1 to 10 equivalents, based on the monocyclopentadienyl complex A).

Suitable activating compounds C) also include boron-aluminum compounds such as di [bis (pentafiuorophenyl) boroxy] methylaiane. Examples of such boron-aluminum compounds are those disclosed in WO 99/06414.

It is also possible to use mixtures of all the abovementioned activating compounds C). Preferred mixtures comprise aluminoxanes, in particular methylaluminoxane, and an ionic compound, in particular one containing the tetrakis (pentafluorophenyl) borate anion, and/or a strong uncharged Lewis acid, in particular tris (pentafiuorophenyl) borane.

Both the monocyclopentadienyl complexes A) and the activating compounds C) are preferably used in a solvent, preferably an aromatic hydrocarbon having from 6 to 20 carbon atoms, in par- ticular xylenes, toluene, pentane, hexane, heptane or a mixture thereof.

A further possibility is to use an activating compound C) which can simultaneously be employed as support B). Such systems are obtained, for example, from an inorganic oxide by treatment with zirconium alkoxide and subsequent chlorination, for example by means of carbon tetrachloride.

The preparation of such systems is described, for example, in WO 01/41920.

A likewise broad product spectrum can be achieved by use of the monocyclopentadienyl com- plexes A) of the present invention in combination with at least one further catalyst D) which is suitable for the polymerization of olefins. It is therefore possible to use one or more catalysts suit- able for olefin polymerization as optional component D) in the catalyst system. Possible catalysts D) are, in particular, classical Ziegler-Natta catalysts based on titanium and classical Phillips cata- lysts based on chromium oxides.

Possible components D) are in principle all compounds of transition metals of groups 3 to 12 of the Periodic Table or the lanthanides which contain organic groups and preferably form active catalysts for olefin polymerization after reaction with the components C) in the presence of A) and optionally B) and/or E). These are usually compounds in which at least one monodentate or polydentate ligand is bound to the central atom via a sigma or pi bond. Possible ligands include both ligands containing cyclopentadienyl groups and ligands which are free of cyclopentadienyl groups. A large number of such compounds B) suitable for olefin polymerization are described in

Chem. Rev. 2000, Vol, 100, No. 4. Furthermore, multinuclear cyclopentadienyl complexes are also suitable for olefin polymerization.

Particularly well-suited components D) include compounds having at least one cyclopentadienyl ligand, which are generally referred to as metallocene complexes. Particularly useful metallocene complexes are those of the formula (XIV) where the substituents and indices have the following meanings: M1D is titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybde- num or tungsten, or an element of group 3 of the Periodic Table and the lantha- nides, X° is fluorine, chlorine, bromine, iodine, hydrogen, C1-C10-alkyl, C2-C10-alkenyl, C6-C15- aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl part, -OR6D or -NR6DR7D, or two radicals X° form a substituted or unsubstituted diene ligand, in particular a 1,3-diene ligand, and the radicals X° are identical or different and may be joined to one another, E1D-E5D are each carbon or not more than one E'D to ESD is phosphorus or nitrogen, pref- erably carbon, t is 1,2 or 3 and is such that, depending on the valence of MID, the metallocene complex of the formula (XIV) is uncharged, where R6D and R7D are each Cl-Clo-alkyl, C6-Cls-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon at- oms in the aryl radical and

R1D to R5D are each, independently of one another, C1-C22-alkyl, 5- to 7-membered cyclo- alkyl or cycloalkenyl which may in turn bear C1-C10-alkyl groups as substituents, C2-C22-alkenyl, C6-C22-aryl, arylalkyl having from 1 to 16 carbon atoms in the al- kyl part and from 6 to 21 carbon atoms in the aryl part, NR8D2, N (SIR 3) 2, OR OSiR8D3, SiR8D3, where the organic radicals R1D-R5D may also be substituted by halogens and/or two radicals R-R, in particular vicinal radicals, may also be joined to form a five-six-or seven-membered ring, and/or two vicinal radicals R1D- R 5D may be joined to form a five-, six-or seven-membered heterocycle which con- tains at least one atom from the group consisting of N, P, O and S, where R8D the radicals R83 can be identical or different and are each C1-C10-alkyl, C3-C10- cycloalkyl, C6-C15-aryl, C1-C4-alkoxy or C6-C10-aryloxy and z1D is defined as for X° or, where the radicals R9D to R'3D are each, independently of one another, hydrogen, C1-C22-alkyl, 5-to 7- membered cycloalkyl or cycloalkenyl which may in turn bear C1-C10-alkyl groups as substituents, C2-C22-alkenyl, C6-C22-aryl, arylalkyl having from 1 to 16 carbon atoms in the alkyl part and 6-21 carbon atoms in the aryl part, NR14D2, N (SiR14D3)2, OR14D, OSiR14D3, SiR14D3, where the organic radicals R9D-R13D may also be substi- tuted by halogens and/or two radicals R9D-R13D, in particular vicinal radicals, may also be joined to form a five-, six-or seven-membered ring, and/or two vicinal radi- cals R9D-R'3D may be joined to form a five-, six-or seven-membered heterocycle which contains at least one atom from the group consisting of N, P, O and S, where R14D the radicals R14D are identical or different and are each C1-C10-alkyl, C3-C10- cycloalkyl, C6-C15-aryl, C1-C4-alkoxy or C6-C10-aryloxy, are each carbon or not more than one E6D to E10D is phosphorus or nitrogen, pref- erably carbon,

or the radicals R4D and Z1D together form an -R15Dv-A1D- group in which R15D = BR16D, = BNR16DR17D, = AIR16D, -Ge-, -Sn-, -O-, -S-, = SO, = SO2, = NR16D = CO, = PR16D or = P(O)R16D, where R'sD-R21D are identical or different and are each a hydrogen atom, a halogen atom, a trimethylsilyl group, a C1-C10-alkyl group, a C1-C10-fluoroalkyl group, a C6- C10-fluoroaryl group, a C6-C10-aryl group, a C1-C10-alkoxy group, a C7-C15- alkylaryloxy group, a C2-C10-alkenyl group, a C7-C4o-arylalkyl group, a C8- C4o-arylalkenyl group or a C7-C4o-alkylaryl group or two adjacent radicals to- gether with the atoms connecting them form a saturated or unsaturated ring having from 4 to 15 carbon atoms, and M2D-M4D are each silicon, germanium or tin, preferably silicon,

- NR22D2, - PR22D2 or an unsubstituted, substituted or fused heterocyclic ring system, where R22D the radicals R22D are each, independently of one another, C1-C10-alkyl, C6- C15-aryl, C3-C10-cycloalkyl, C7-C18-alkylaryl or Si (R23D)3, IS hydrogen, C1-C10-alkyl, C6-C15-aryl which may in turn bear C1-C4-alkyl groups as substituents or C3-C10-cycloalkyl, v is 1 or when A1D is an unsubstituted, substituted or fused heterocyclic ring system may also be 0, or the radicals R4D and R12D together form a-R15D-group.

A1D together with the bridge R'50 can, for example, form an amine, ether, thioether or phosphine.

However, A'D may also be an unsubstituted, substituted or fused heterocyclic aromatic ring sys- tem which can contain heteroatoms from the group consisting of oxygen, sulfur, nitrogen and phosphorus in addition to carbon atoms in the ring. Examples of five-membered heteroaryl groups which can contain from one to four nitrogen atoms and/or a sulfur or oxygen atom as ring atoms in addition to carbon atoms are 2-fury, 2-thienyl, 2-pyrrolyl, 3-isoxazolyl, 5-isoxazolyl, 3-isothiazolyi, 5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1,2, 4-oxadiazol-3-yl, 1,2, 4- oxadiazol-5-yl, 1,3, 4-oxadiazol-2-yl or 1,2, 4-triazol-3-yl. Examples of 6-membered heteroaryl groups, which can contain from one to four nitrogen atoms and/or a phosphorus atom, are 2-pyridinyl, 2-phosphaphenyl, 3-pyridaziny), 2-pyrimidinyl, 4-pyrimidinyl, 2-pyrazinyl, 1,3, 5-triazin- 2-yl and 1,2, 4-triazin-3-yl, 1,2, 4-triazin-5-yl and 1,2, 4-triazin-6-y !. The 5-membered and 6-membered heteroaryl groups can also be substituted by C1-C10-alkyl, C6-C10-aryl, alkylaryl hav- ing from 1 to 10 carbon atoms in the alkyl part and 6-10 carbon atoms in the aryl part, trialkylsilyl or halogens such as fluorine, chlorine or bromine or be fused with one or more aromatics or het- eroaromatics. Examples of benzo-fused 5-membered heteroaryl groups are 2-indoly), 7-indolyl, 2-coumaronyl, 7-coumaronyl, 2-thianaphthenyl, 7-thianaphthenyl, 3-indazolyl, 7-indazolyl, 2-benzimidazolyl and 7-benzimidazolyl. Examples of benzo-fused 6-membered heteroaryl groups are 2-quinolyl, 8-quinolyl, 3-cinnolyl, 8-cinnolyl, 1-phthalazyl, 2-quinazolyl, 4-quinazolyl, 8-quinazolyi, 5-quinoxalyl, 4-acridyl, 1-phenanthridyl and 1-phenazyl. Naming and numbering of the heterocycles has been taken from L. Fieser and M. Fieser, Lehrbuch der organischen Che- mie, 3rd revised edition, Verlag Chemie, Weinheim 1957. it is preferred that the radicals X° in the formula (XIV) are identical, preferably fluorine, chlorine, bromine, C1-C7-alkyl or aralkyl, in particular chlorine, methyl or benzyl.

The synthesis of such complexes can be carried out by methods known per se, preferably by reaction of the appropriately substituted, cyclic hydrocarbon anions with halides of titanium, zirco- nium, hafnium or chromium.

Among the metallocene complexes of the formula (XIV), preference is given to

Among the compounds of the formula (XIVa), particular preference is given to those in which M'D is titanium, vanadium or chromium, XD is chlorine, Ct-C4-alkyl, phenyl, alkoxy or aryloxy, t is 1 or 2 and R'D to R5D are each hydrogen, C1-C6-alkyl or two adjacent radicals R1D to R5D form a sub- stituted or unsubstituted benzo group.

Among the compounds of the formula (XlVb), preference is given to those in which M'D is titanium, zirconium, vanadium, hafnium or chromium, XD is fluorine, chlorine, C1-C4-alkyl or benzyl, or two radicals X° form a substi- tuted or unsubstituted butadiene ligand, t is 0 in the case of chromium, otherwise 1 or 2, preferably 2, R'D to R5D are each hydrogen, C1-C8-alkyl, C6-C8-aryl, NR8D2, OSiR8D3 or Si (R3D) 3 and R9D to R13D are each hydrogne, C1-C8-alkyl or C6-C8-aryl, NR14D2, OSiR14D3 or Si(R14D)3 or two radicals R1D to R5D and/or R9D to R13D together with the C5 ring form an indenyl, fluorenyl or substituted indenyl or fluorenyl system.

The compounds of the formula (X) Vb) in which the cyclopentadienyl radicals are identical are particularly useful.

Examples of particularly useful compounds D) of the formula (XlVb) include : bis (cyclopentadienyl) chromium, bis (indenyl) titanium dichloride, bis (fluorenyl) titanium dichloride, bis (tetrahydroindenyl) titanium dichloride, bis (pentamethylcyclopentadienyl) titanium dichloride, bis (trimethylsilylcyclopentadienyl) titanium dichloride, bis (trimethoxysilylcyclopentadienyl) titanium dichloride, bis(isobutylcyclopentadienyl)titanium dichloride, bis (3-butenylcyclopentadienyl)titanium dichloride, bis (methylcyclopentadienyl) titanium dichloride, bis (1-, 3-di-tert- butylcyclopentadienyl) titanium dichloride, bis(trifluoromethylcyclopentadienyl)titanium dichloride, bis (tert-butylcyclopentadienyl) titanium dichloride, bis (n-butylcyclopentadienyl) titanium dichloride, bis (phenylcyclopentadienyl) titanium dichloride, bis (N, N-dimethylaminomethylcyclopentadienyl)- titanium dichloride, bis (1, 3-dimethylcyclopentadienyl) titanium dichloride, bis (1-methyl-3-n-butyl- cyclopentadienyl)titanium dichloride, (cyclopentadienyl)(methylcyclopentadienyl)titanium dichlo- ride, (cyclopentadienyl) (n-butylcyclopentadienyl) titanium dichloride, (methylcyclopentadienyl) (n-

butylcyclopentadienyl) titanium dichloride, (cyclopentadienyl) (1-methyl-3-n- butylcyclopefitadienyl) titanium dichloride, bis (cyclopentadienyl) zirconium dichloride, bis (penta- methylcyclopentadienyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dichloride, bis (ethylcyclopentadienyl) zirconium dichloride, bis (n-butylcyclopentadienyl)zirconium dichloride, bis (tert-butyicyclopentadienyl) zirconium dichloride, bis (isobutylcycfopentadienyl) zirconium dichlo- ride, bis (3-butenylcyclopentadienyl) zirconium dichloride, bis (trifluoromethyl- cyclopentadienyl) zirconium dichloride, bis (phenylcyclopentadienyl) zirconium dichloride, bis (1,3- dimethylcyclopentadienyl) zirconium dichloride, bis (1-n-butyl-3-methylcyclopentadienyl) zirconium dichloride, bis (1, 3-ditert-butylcyclopentadienyl) zirconium dichloride, bis (tetramethylcyclopenta- dienyl) zirconium dichloride, bis (indenyl) zirconium dichloride, bis (tetrahydroindenyl) zirconium di- chloride, bis (fluorenyl) zirconium dichloride, (cyclopentadienyl) (methylcyclopentadienyl) zirconium dichloride, (cyclopentadienyl) (n-butylcyclopentadienyl) zirconium dichloride, (methylcyclopenta-<BR> dienyl) (n-butyfcyclopentadienyl) zirconium dichloride, (cyclopentadienyl) (1-methyl-3-n-butyl- cyclopentadienyl) zirconium dichloride, bis (trimethoxysilylcyclopentadienyl) zirconium dichloride and bis (trimethylsiiylcyclopentadienyl) zirconium dichloride, and also the corresponding dimethyl- zirconium compounds.

Particularly useful compounds of the formula (XIVc) are those in which R1sD is or = BR16D or = BNR16DR17D, M1D is titanium, zirconium or hafnium, in particular zirconium, and XD the radicals X° are identical or different and are each chlorine, C1-C4-alkyl, benzyl, phenyl or C7-C15-alkylaryloxy.

Particularly useful compounds of the formula (XVIc) are those of the formula (XVIc')

where the radicals R'are identical or different and are each hydrogen, C1-C10-alkyl or C3-Co-cycloalkyl, preferably methyl, ethyl, isopropyl or cyclohexyl, C6-C2o-aryl, preferably phenyl, naphthyl or me- sityl, C7-C4o-arylalky (, C7-C4o-alkylaryl, preferably 4-tert-butylphenyl or 3, 5-di-tert-butylphenyl, or C8-C4o-arylalkenyl, R and R'3D are identical or different and are each hydrogen, C1-C6-alkyl, preferably methyl, ethyl, isopropyl, n-propyl, n-butyl, n-hexyl or tert-butyl, And the rings S and T are identical or different and saturated, unsaturated or partially saturated.

The indenyl or tetrahydroindenyl ligands of the metallocenes of the formula (XIVc') are preferably substituted in the 2 position, the 2,4 positions, the 4,7 positions, the 2,4, 7 positions, the 2,6 posi- tions, the 2,4, 6 positions, the 2,5, 6 positions, the 2,4, 5,6 positions or the 2,4, 5,6, 7 positions, in particular in the 2,4 positions, with the following numbering applying to the site of substitution : Furthermore, preference is given to using bridged bis-indenyl complexes in the rac or pseudo-rac form as component D). The term"pseudo-rac form"refers to complexes in which the two indenyl ligands are in the rac arrangement relative to one another when all other substituents of the com- plex are disregarded.

Further examples of particularly useful catalysts D) (XlVc) and (XlVc') include : methylenebi (cyclopentadienyl) zirconium dichloride, methylenebis (3-methylcyclopentadienyl)- zirconium dichloride, methylenebis (3-n-butylcyclopentadienyl) zirconium dichloride, methylene- bis (indenyl) zirconium dichloride, methylenebis (tetrahydroindenyl) zirconium dichloride, isopro- pylidenebis (cyclopentadienyl) zirconium dichloride, isopropylidenebis (3- trimethylsilylcyclopentadienyl) zirconium dichloride, isopropylidenebis (3- methylcyclopentadienyl) zirconium dichloride ; isopropylidenebis (3-n-butylcyclopenta- dienyl) zirconium dichloride, isopropylidenebis (3-phenylcyclopentadienyl) zirconium dichloride, iso- propylidenebis (indenyl) zirconium dichloride, isopropylidenebis (tetrahydroindenyl) zirconium dichlo- ride, dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride, dimethylsilanediyl- bis (indenyl) zirconium dichloride, dimethylsilanediylbis (tetrahydroindenyl) zirconium dichloride, ethylenebis(cyclopentadienyl)zirconium dichloride, ethylenebis(indenyl) zirconium dichloride, ethylenebis (tetrahydroindenyl) zirconium dichloride, tetramethylethylen-9- fluorenylcyclopentadienylzirconium dichloride, dimethylsilanediylbis (tetra- methyicyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (3-trimethylsilylcyclopenta- dienyl) zirconium dichloride, dimethylsilanediylbis (3-methylcyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (3-n-butylcyclopentadienyl) zirconium dichloridedimethylsilanediylbis (3-tert- butyl-5-methylcyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (3-tert-butyl-5-ethyl- cyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (2-methylindenyl) zirconium dichloride, <BR> <BR> <BR> dimethylsilanediylbis (2-isopropylindenyl) zirconium dichloride, dimethylsilanediylbis (2-tert-butylin- denyl) zirconium dichloride, diethylsilanediylbis (2-methylindenyl) zirconium dibromide, dimethylsi- <BR> <BR> <BR> lanediylbis (3-methyi-5-methylcyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (3-ethy)- 5-isopropylcyclopentadienyl) zirconium dichloride, dimethylsilanediylbis (2-ethylindenyl) zirconium dichloride, dimethylsilanediylbis (2-methyl-4, 5-benzindenyl) zirconium dichloride, dimethyl- silanediylbis (2-ethyl-4, 5-benzindenyl) zirconium dichloride, methylphenylsilanediylbis (2-methyl- 4, 5-benzindenyl) zirconium dichloride, methy, phenylsilanediylbis (2-ethyl4, 5- benzindenyl) zirconium dichloride, diphenylsilanediyibis (2-methyl-4, 5-benzindenyl) zirconium di- chloride, diphenylsilanediylbis (2-ethyl-4, 5-benzindenyl) zirconium dichloride, diphenylsilanediyi- bis (2-methylindenyl) hafniumdichloride, dimethylsilanediylbis (2-methyl-4-phenyiindenyl) zirconium dichloride, dimethylsilanediylbis (2-ethyl-4-phenylindenyl) zirconium dichloride, dimethylsilanedi- ylbis (2-methyl-4- (1-naphthyl) indenyi) zirconium dichioride, dimethylsilanediylbis (2-ethyl4-(1- naphthyl) indenyl) zirconium dichloride, dimethylsilanediylbis (2-propyl-4- (1-naph- thyl) indenyl) zirconium dichloride, dimethylsilanediylbis (2-i-butyl-4- (1-naphthyl) indenyl) zirconium dichloride, dimethylsilanediylbis (2-propyl-4- (9-phenanthryl) indenyl) zirconium dichloride, dimethyl- silanediylbis(2-methyl-4-isopropylindenyl) zirconium dichloride, dimethylsilanediylbis (2,7- dimethyl-4-isopropylindenyl) zirconium dichloride, dimethylsilanediylbis (2-methyl-4, 6- diisopropylindenyl) zirconium dichloride, dimethylsilanediylbis (2-methyl-4 [p-trifluoromethylphenyl]- indenyl) zirconium dichloride, dimethylsilanediylbis (2-methyl-4- [3', 5'-dimethyiphenyl] inde- nyl) zirconium dichloride, dimethylsilanediylbis (2-methyl-4- [4'-tert-butylphenyi] indenyl)-zirconium dichloride, diethylsilanediylbis (2-methyl-4- [4'-tert-butylphenyl] indenyl)-zirconium dichloride, di-

methylsilanediyibis (2-ethyl-4- [4'-tert-butylphenyl] indenyl)-zirconium dichloride, dimethyl-<BR> <BR> <BR> <BR> silanediylbis (2-propyl-4- [4'-tert-butylphenyl] indenyl)-zirconium dichloride, dimethylsilanediyl- bis (2-isopropyl-4- [4'-tert-butylphenyl] indenyl)-zirconium dichloride, dimethylsilanediylbis (2-n- <BR> <BR> <BR> butyl-4- [4'-tert-butylphenyl] indenyl)-zirconium dichloride, dimethylsilanediylbis (2-hexyl-4-j4'-<BR> <BR> <BR> <BR> tert-butylphenyl] indenyl)-zirconium dichloride, dimethylsilanediyl (2-isopropyl-4-phenylindenyl)-<BR> <BR> <BR> <BR> (2-methyl-4-phenylindenyl) zirconium dichloride, dimethylsilanediyl (2-isopropyl-4- (1- naphthyl) indenyl)- (2-methyl-4- (1-naphthyl) indenyl) zirconium dichloride, dimethylsilanediyl (2- isopropyl-4- [4'-tert-butylphenyl] indenyl)- (2-methyl-4- [4'-tert-butylphenyl) indenyl) zirconium di- <BR> <BR> <BR> chloride, dimethylsilanediyl (2-isopropyl-4- [4'-tert-butylphenyl] indenyl)- (2-ethyl-4- [4'-tert-butyl-<BR> <BR> <BR> <BR> phenyl] indenyl) zirconium dichloride, dimethylsilanediyl (2-isopropyl-4- [4'-tert-butyl-<BR> <BR> <BR> <BR> phenyl] indenyl)- (2-methyl-4- [3', 5'-bis-tert-butylphenyl] indenyl) zirconium dichl. oride, dimethylsi- lanediyl (2-isopropyl-4- [4'-tert-butylphenyl] indenyl)- (2-methyl-4- [1'-naphthyl] indenyl) zirconium dichloride and ethylene (2-isopropyi-4- [4'-tert-butylphenyl] indenyl)- (2-methyl-4- [4'-tert-butyl- phenyl] indenyl) zirconium dichloride, and also the corresponding dimethylzirconium, monochloro- mono (alkylaryloxy) zirconium and di (alkylaryloxy) zirconium compounds. The complexes are pref- erably used in the rac form.

Such complexes can be synthesized by methods known per se, preferably by reacting the appro- priately substituted, cyclic hydrocarbon anions with halides of titanium, zirconium, hafnium, vana- dium, niobium, tantalum or chromium. Examples of appropriate preparative methods are de- scribed, inter alia, in the Journal of Organometallic Chemistry, 369 (1989), 359-370.

Particularly useful compounds of the formula (XlVd) are those in which MID is titanium or zirconium, in particular titanium, and XD is chlorine, C,-C4-alkyl or phenyl or two radicals X° form a substituted or unsubstituted butadiene ligand, R1 SD or = BR16D or = BNR16DR17D, t is 1 or 2, preferably 2,

pic to R3D and R5D are each hydrogen, C1-10-alkyl, preferably methyl, C3-C10-cycloalkyl, C6- C15-aryl, NR8D2 or Si (R8D) 3, or two adjacent radicals form a cyclic group having from 4 to 12 carbon atoms, with particular preference being given to all R'D to R3D and RSD being methyl.

Particularly useful complexes D) of the formula (XlVd) are dimethylsilanediyl (tetramethyl- <BR> <BR> <BR> cyclopentadienyl) (phenylamino) titanium dichloride, dimethylsi-<BR> <BR> <BR> <BR> lanediyl (tetramethylcyclopentadienyl) (benzylamino) titanium dichloride, dimethylsi- lanediyl (tetramethylcyclopentadienyl) (tert-butylamino) titanium dichloride, dimethylsi- lanediyl (tetramethylcyclopentadienyl) (adamantyl) titanium dichloride and dimethylsi- lanediyl(indenyl)(tert-butylamino)titanium dichloride.

Another group of compounds of the formula (XlVd) which are particularly useful are those in which M'D is titanium, vanadium or chromium, preferably in the oxidation state III, and XD is chlorine, C,-C4-alkyl or phenyl or two radicals X° form a substituted or unsubstituted butadiene ligand, R15D is AI is -O-R22D, -NR22D2, -PR22D2 or an unsubstituted, substituted or fused, heterocyclic, in particular heteroaromatic, ring system, v is 1 or when A'D is an unsubstituted, substituted or fused, heterocyclic ring system may be 0 or 1 and R1D to R3D and R5D are each hydrogen, C1-C10-alkyl, C3-C10-cycloalkyl, C6-C15-aryl or Si (R8D)3, or two adjacent radicals form a cyclic group having from 4 to 12 carbon atoms.

In a preferred embodiment, A'D is an unsubstituted, substituted or fused, heteroaromatic ring sys- tem and M'duits chromium. Very particular preference is given to A'D being an unsubstituted or substituted, e. g. alkyl-substituted, in particular substituted or unsubstituted quinolyl or pyridyl bound in position 8 or 2, e. g. 8-quinolyl, 8- (2-methylquinolyl), 8- (2, 3, 4-trimethylquinolyl), 8- (2, 3,4, 5,6, 7-hexamethylquinolyl), v being 0 and MlD being chromium. Preferred catalysts D) of this type are 1- (8-quinolyl)-2-methyl-4-methylcyclopentadienylchromium (III) dichioride, 1- (8-quinolyi)-3-isopropyl-5-methyicyclopentadienylchromium (lII) dichloride, 1- (8-quinolyl)-3-tert- butyl-5-methylcyclopentadienylchromium (lll) dichloride, 1- (8-quinolyl)-2, 3, 4,5-tetra- methylcyclopentadienyichromium (III) dichioride, 1- (8-quinolyl) tetrahydroindenylchromium (Ill) di- <BR> <BR> <BR> chloride, 1- (8-quinolyl) indenylchromium ( ll) dichioride, 1- (8-quinolyl)-2-methylindenylchromium (ilI)<BR> <BR> <BR> <BR> <BR> dichloride, 1- (8-quinolyl)-2-isopropylindenylchromium (III) dichloride, 1- (8-quinolyl)-2-ethylindenyl- chromium (III) dichloride, 1- (8-quinolyl)-2-tert-butylindenylchromium(III) dichloride, 1- (8-quinolyl)benzindenylchromium(III) dichloride, 1-(8-quinolyl)-2-methylbenzindenylchromium(III) dichloride, 1- (8- (2-methylquinolyl))-2-methyl-4-methylcyclopentadienylchromiu m (Ili) dichloride, 1- (8- (2-methylquinolyi))-2, 3,4, 5-tetramethylcyclopentadienylchromium (I I) dichloride, 1- (8- (2- methylquinolyl))tetrahydroindenylchromium(III) dichloride, 1-(8-(2-methylquinolyl))indenyl- chromium (III) dichloride, 1-(8-(2-methylquinolyl))-2-methylindenylchromium(III) dichloride, 1-(8-(2- methylquinolyl))-2-isopropylindenylchromium(III) dichloride, 1-(8-(2-methylquinolyl))-2- ethylindenylchromium (lil) dichloride, 1- (8- (2-methylquinolyl))-2-tert-butylindenylchromium (iIl) di- chloride, 1- (8- (2-methylquinolyl)) benzindenylchromium (lIl) dichloride, 1- (2- pyridylmethyl) indenylchromium (ill) dichloride or 1- (8- (2-methylquinolyl))- 2-methylbenzindenyichromium (III) dichloride.

Furthermore, owing to the ease of preparation, preference is given to compounds in which R'5D is CH=CH or 1, 2-phenylene and A'D is NR22D2, and compounds in which Rr5D is CH2, C (CH3) 2 or Si (CH3) 2 and A'D is unsubstituted or substituted 2-or 8-quinolyl or unsubstituted or substituted 2- pyridyl.

The preparation of such functional cyclopentadienyl ligands has been known for a long time. Vari- ous synthetic routes to these complexing ligands are described, for example, by M. Enders et al. in Chem. Ber. (1996), 129,459-463, or P. Jutzi and U. Siemeling in J. Orgmet. Chem. (1995), 500,175-185.

The metal complexes, in particular the chromium complexes, can be obtained in a simple manner by reacting the appropriate metal salts, e. g. metal chlorides, with the igand anion (e. g. using methods analogous to the examples in DE-A-19710615).

Further suitable catalysts D) include metallocenes having at least one ligand which is formed from a cyclopentadienyl or heterocyclopentadienyl and a fused-on heterocycle, with the heterocycles preferably being aromatic and containing nitrogen and/or sulfur. Such compounds are described,

for example, in WO 98/22486. These are in particular dimethylsilanediyl (2-methyl-4-phenyl- indenyl) (2, 5-dimethyl-N-phenyl-4-azapentalene) zirconium dichloride, dimethyisilanediylbis (2- methyl-4-phenyl-4-hydroazulenyl) zirconium dichloride, dimethylsilanediylbis (2-ethyl-4-phenyl-4- hydroazulenyl) zirconium dichloride, bis (2, 5-dimethyl-n-phenyl-4-azapentalene) zirconium dichlo- ride or (indenyl)(2,5-dimethyl-N-phenyl-4-azapentalene)zirconium dichloride.

Further suitable catlaysts D) are systems in which a metallocene compound is combined with, for example, an inorganic oxide which has been treated with zirconium alkoxide and subsequently chlorinated, for example by means of carbon tetrachloride. The preparation of such systems is described, for example, in WO 01/41920.

Other suitable catalysts D) include imidochromium compounds in which chromium bears at least one imido group as structural feature. These compounds and their preparation are described, for example, in WO 01/09148.

Further suitable components D) include transition metal complexes with a tridentate macrocyclic ligand, in particular substituted and unsubstituted 1,3, 5-triazacyclohexanes and 1,4, 7- triazacyclononanes. In the case of this type of catalyst, preference is likewise given to chromium complexes. Preferred catalysts of this type are [1,3, 5-tri (methyl)-1, 3,5- 'triazacyclohexane] chromium trichloride, [1,3, 5-tri (ethyl)-1, 3, 5-triazacyclohexane] chromium trichlo- ride, [1,3,5-tri(octyl)-1,3,5-triazacyclohexane]chromium trichloride, [1,3,5-tri(dodecyl)-1,3,5-triaza- cyclohexane]chromium trichloride and [1,3,5-tri(benzyl)-1,3,5-triazacyclohexane]chromium trichlo- ride.

Further suitable catalysts D) are, for example, transition metal complexes with at least one ligand of the formulae XV to XIX,

where the transition metal is selected from among the elements Ti, Zr, Hf, Sc, V, Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Pd, Pt and the elements of the rare earth metals. Preference is given to com- pounds having nickel, iron, cobalt or palladium as central metal.

EF is an element of group 15 of the Periodic Table of the Elements, preferably N or P, with par- ticular preference being given to N. The two or three atoms EF in a molecule can be identical or different.

The radicals R to R25F, which may be identical or different within a ligand system XV to XIX, are as follows : R1F and R4F are each, independently of one another, a hydrocarbon radical or a substituted hy- drocarbon radical, preferably a hydrocarbon radical in which the carbon atom adja- cent to the element EF is bound to at least two carbon atoms, R2F and R3F are each, independently of one another, hydrogen, a hydrocarbon radical or a substi- tuted hydrocarbon radical, where R2F and R3F may together also form a ring system in which one or more heteroatoms may also be present, R6F and R8F are each, independently of one another, a hydrocarbon radical or a substituted hy- drocarbon radical,

R5F and R9F gre each, independently of one another, hydrogen, a hydrocarbon radical or a substi- tuted hydrocarbon radical, where R6F and R5F or R8F and R9F may together also form a ring system, R7F the radicals R7F are each, independently of one another, hydrogen, a hydrocarbon radical or a substituted hydrocarbon radical, where two R7F may together also form a ring system, R10F and R14F are each, independently of one another, a hydrocarbon radical or a substituted hy- drocarbon radical, R11F, R12F, R12F' and R13F are each, independently of one another, hydrogen, a hydrocarbon radi- cal or a substituted hydrocarbon radical, where two or more geminal or vicinal radi- cals R'IA, R12A R12A'and R13A may together also form a ring system, R16F and R18F are each, independently of one another, hydrogen, a hydrocarbon radical or a sub- stituted hydrocarbon radical, R'6F and R17F are each, independently of one another, hydrogen, a hydrocarbon radical or a sub- stituted hydrocarbon radical, R'9F and R25F are each, independently of one another, C2-C20-alkenyl, C6-c20-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, where the organic radicals R 9F and R25F may also be substituted by halogens, R20F-R24F are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6-C2o-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR26F3, where the organic radicals R20F-R24F may also be substituted by halogens and two vicinal radicals R20F-R24F may also be joined to form a five-or six-membered ring and R25F the radicals R26F are each, independently of one another, hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R26F may also be joined to form a five-or six-membered ring, x is 0 or 1, with the complex of the formula (XVI) being negatively charged when x is 0, and

y is an integer from 1 to 4, preferably 2 or 3.

Particularly useful transition metal complexes are those having Fe, Co, Ni, Pd or Pt as central metal and containing ligands of the formula (XV). Particular preference is given to diimine com- plexes of Ni or Pd, e. g.: Di (2, 6-di-i-propylphenyl)-2,3-dimethyldiazabutadienepalladium dichloride, di (di-i-propylphenyl)- 2, 3-dimethyidiazabutadienenickel dichloride, di (2, 6-di-i-propyl- phenyl) dimethyldiazabutadienedimethylpalladium, di (2, 6-di-i-propylphenyl)-2,3-dimethyldiaza- butadienedimethyinickel, di (2, 6-dimethylphenyl)-2,3-dimethyldiazabutadienepalladium dichloride, di (2, 6-dimethylphenyl)-2,3-dimethyldiazabutadienenickel dichloride, di (2, 6-dimethylphenyl)-2, 3- dim ethyldiazabutadiened imethylpalladium, di (2, 6-dimethylphenyl)-2, 3-dimethyldiaza- butadienedimethyinicke., di (2-methylphenyl)-2, 3-dimethyidiazabutadienepalladium dichloride, di (2-methyiphenyl)-2, 3-dimethyidiazabutadienenickel dichloride, di (2-methylphenyl)-2, 3- dimethyldiazabutadienedimethylpalladium, di (2-methylphenyl)-2, 3- <BR> <BR> <BR> dimethyidiazabutadienedimethylnickel, diphenyl-2, 3-dimethyidiazabutadienepalladium dichloride, diphenyl-2, 3-dimethyidiazabutadienenickel dichloride, diphenyl-2, 3- <BR> <BR> dimethyldiazabutadienedimethylpalladium, diphenyl-2, 3-dimethyldiazabutadienedimethylnickel, di (2, 6-dimethylphenyl) azanaphthenepalladium dichloride, di (2,6- dimethylphenyl)azanapththenenickel dichloride, di (2,6- dimethylphenyl)azanaphthenedimethylpalladium, di (2, 6-dimethyl- phenyl) azanaphthenedimethylnickel, 1, 1'-bipyridylpalladium dichloride, 1, 1'-bipyridylnickel dichlo- ride, 1, 1'-bipyridyl (dimethyl) palladium, 1, 1'-bipyridyl(dimethyl)nickel.

Particularly useful compounds (XIX) also include those which are described in J. Am. Chem. Soc.

120, p. 4049 ff. (1998), J. Chem. Soc. , Chem. Commun. 1998,849, and WO 98/27124. EF is pre- ferably nitrogen and R>9F and R25F in (XIX) are preferably phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2, 5- or 2,6-dimethylphenyl, -dichlorophenyl or -dibromophenyl, 2- chloro-6-methylphenyl, 2,3, 4-, 2,3, 5-, 2,3, 6-, 2,4, 5-, 2,4, 6- or 3,4, 5-trimethylphenyl, in particular 2, 3- or 2, 6-dimethylphenyl,-diisopropylphenyl,-dichlorophenyl or-dibromophenyl and 2,4, 6-trimethylphenyl. At the same time, R20F and R24F are preferably hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, benzyl or phenyl, in par- ticular hydrogen or methyl. R21F and R23F are preferably hydrogen and R22F is preferably hydro- gen, methyl, ethyl or phenyl, in particular hydrogen. Preference is given to complexes of the ligands F-XIX with the transition metals Fe, Co or Ni, in particular Fe. Particular preference is given to 2, 6-diacetylpyridinebis (2, 4-dimethylphenylimine) iron dichloride, 2,6- diacetylpyridinebis (2,4, 6-trimethylphenylimine) iron dichloride, 2, 6-diacetylpyridinebis (2-chloro-6- methylphenylimine) iron dichloride, 2, 6-diacetylpyridinebis (2, 6-diisopropylphenylimine) iron dichlo- ride, 2, 6-diacetylpyridinebis (2, 6-dichlorophenylimine) iron dichloride,

2, 6-pyridinedicarboxaldehydebis (2, 6-diisopropylphenylimine) iron dichloride, 2, 6- diacetylpyridinebis (2, 4-dimethylphenylimine) cobalt dichloride, 2, 6-diacetylpyridinebis (2,4, 6-trimethylphenylimine) cobalt dichloride, 2, 6-diacetylpyridinebis (2- chloro-6-methylphenylimine) cobalt dichloride, 2, 6-diacetylpyridinebis (2, 6-diisopropylphenyl- imine) cobalt dichloride, 2, 6-diacetylpyridinebis (2, 6-dichlorophenylimine) cobalt dichloride, and 2, 6-pyridinedicarboxaldehydebis (2, 6-diisopropylphenylimine) cobalt dichloride.

Iminophenoxide complexes can also be used as catalysts D). The ligands of these complexes can be prepared, for example, from substituted or unsubstituted salicylaldehydes and primary amines, in particular substituted or unsubstituted arylamines. Transition metal complexes with pi ligands having one or more heteroatoms in the pi system, for example the boratabenzene ligand, the pyrrolyl anion or the phospholyl anion, can also be used as catalysts D).

Further complexes suitable as catalysts D) include those which have bidentate or tridentate che- lating ligands. In such ligands, for example, an ether function is linked to an amine or amide func- tion or an amide is linked to a heteroaromatic such as pyridine.

Such combinations of components A) and D) enable, for example, bimodal products to be pre- pared or comonomers to be generated in situ. Preference is given to using at least one mono- cyclopentadienyl complex A) in the presence of at least one further catalyst D) customary for the polymerization of olefins and if desired, one or more activating compounds C). Here, depending on the catalyst. combinations A) and D), one or more activating compounds C) may be advanta- geous. The polymerization catalysts D) can likewise be supported and can be used simultane- ously or in any order with the complex A) of the present invention. For example, the mono- cyclopentadienyl complex A) and the polymerization catalysts D) can be applied together to a support B) or different supports B). It is also possible to use mixtures of various catalysts as com- ponent D). The molar ratio of transition metal complex A) to polymerization catalyst D) is usually in the range from 1: 100 to 100: 1, preferably from 1: 10 to 20: 1 and particularly preferably from 1: 1 to 10: 1.

The catalyst system may further comprise, as additional component E), a metal compound of the formula (XX), MG (R1G)rG(R2G)sG(R3G)tG (XX) where MG is Li, Na, K, Be, Mg, Ca, Sr, Ba, boron, aluminum, gallium, indium, thallium, zinc, in particular Li, Na, K, Mg, boron, aluminum or Zn,

R1G is hydrogen, Cl-Clo-alkyl, C6-C, 5-aryl, alkylaryl or arylalkyl each having from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl part, R2G and R3G are each hydrogen, halogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl, arylalkyl or alkoxy each having from 1 to 20 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, or alkoxy with C1-C10-alkyl or C6-C15-aryl, rG is an integer from 1 to 3 and sG and tG are integers from 0 to 2, with the sum rG + sG + tG correspondign to the valence of MG, where the component E) is not identical to the component C). It is also possible to use mixtures of various metal compounds of the formula (XX).

Among the metal compounds of the formula (XX), preference is given to those in which MG is lithium, magnesium, boron or aluminum and R1G is C1-C20-a ky Particularly preferred metal compounds of the formula (XX) are methyllithium, ethyllithium, n-butyllithium, methylmagnesium chloride, methylmagnesium bromide, ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesium chloride, dimethylmagnesium, diethylmagnesium, dibutylmagnesium, n-butyl-n-octylmagnesium, n-butyl-n-heptylmagnesium, in particular n-butyl- n-octylmagnesium, tri-n-hexylaluminum, triisobutylaluminum, tri-n-butylaluminum, triethylalumi- num, dimethyla (uminum chloride, dimethylaluminum fiuoride, methylaluminum dichloride, methy- laluminum sesquichloride, diethylaluminum chloride and trimethylaluminum and mixtures thereof.

The partial hydrolysis products of aluminum alkyls with alcohols can also be used.

When a metal compound E) is used, it is preferably present in the catalyst system in such an amount that the molar ratio of MG from formula (XX) to transition metal from monocyclopentadi- enyl compound A) is from 2 000: 1 to 0.1 : 1, preferably from 800: 1 to 0.2 : 1 and particularly prefera- bly from 100: 1 to 1: 1.

In general, the catalyst solid together with the further metal compound E) of the formula (XX), which may be different from the metal compound or compounds E) used in the preparation of the catalyst solid, is used as constituent of a catalyst system for the polymerization or copolymeriza-

tion of olefins. It is also possible, particularly when the catalyst solid does not contain any activat- ing component C), for the catalyst system to further comprise, in addition to the catalyst solid, one or more activating compounds C) which are identical to or different from any activating com- pounds C) present in the catalyst solid.

To prepare the catalyst systems of the present invention, preference is given to immobilizing at least one of the components A) and/or C) on the support B) by physisorption or by means of chemical reaction, i. e. covalent binding of the components, with reactive groups of the support surface. The order in which the support component B), the component A) and any component C) are combined is immaterial. The components A) and C) can be added independently of one an- other or simultaneously or in premixed form to B). After the individual process steps, the solid can be washed with suitable inert solvents such as aliphatic or aromatic hydrocarbons.

In a preferred embodiment the monocyclopentadienyl complex A) is brought into contact with the activating compound C) in a suitable solvent, usually giving a soluble reaction product, an adduct or a mixture. The preparation obtained in this way is then brought into contact with the support B), which may have been pretreated, and the solvent is completely or partly removed. This preferably gives a solid in the form of a free-flowing powder. Examples of the industrial implementation of the above process are described in WO 96/00243, WO 98/40419 or WO 00/05277. A further pre- ferred embodiment comprises firstly applying the activating compound C) to the support B) and subsequently bringing this supported activating compound into contact with the monocyclopenta- dienyl complex A).

The component D) can likewise be reacted in any order with the components A) and, if desired, B), C) and E). Preference is given to bringing D) firstly into contact with component C) and then dealing with the components A) and B) and any further C) as described above. In another pre- ferred embodiment, a catalyst solid is prepared from the components A), B) and C) as described above and this is brought into contact with the component E) during, at the beginning of or shortly before the polymerization. Preference is given to E) firstly being brought into contact with the a- olefin to be polymerized and the catalyst solid comprising the components A), B) and C) as de- scribed above subsequently being added. The monocyclopentadienyl complex A) can be brought into contact with the component (s) C) and/or D) either before or after being brought into contact with the olefins to be polymerized. Preactivation using one or more components C) prior to mixing with the olefin and further addition of the same or different components C) and/or D) after the mixture has been brought into contact with the olefin is also possible. Preactivation is generally carried out at 10-100°C, in particular 20-80°C.

It is also possible for the catalyst system firstly to be prepolymerized with o-olefins, preferably linear C2-G10-1-a, kenes and in particular ethylene or propylene, and the resulting prepolymerized

catalyst solid then to be used in the actual polymerization. The mass ratio of catalyst solid used in the prepoiymerization to monomer to be polymerized onto it is usually in the range from 1 : 01 to 1: 1 000, preferably from 1: 1 to 1: 200.

Furthermore, a small amount of an olefin, preferably an a-olefin, for example vinylcyclohexane, styrene or phenyidimethylvinylsilane, as modifying component, an antistatic or a suitable inert compound such as a wax or oil can be added as additive during or after the preparation of the catalyst system. The molar ratio of additives to transition metal compound B) is usually from 1: 1 000 to 1 000: 1, preferably from 1: 5 to 20: 1.

The catalyst systems of the present invention are suitable for the polymerization of olefins and especially for the polymerization of a-olefins, i. e. hydrocarbons having terminal double bonds.

Suitable monomers also include functionalized olefinicaiiy unsaturated compounds such as ac- rolein, ester or amide derivatives of acrylic or methacrylic acid, for example acrylates, methacry- lates or acrylonitrile, or vinyl esters, for example vinyl acetate. Preference is given to nonpolar olefinic compounds, including aryl-substituted a-olefins. Particularly preferred a-olefins are linear or branched C2-Cl2-1-alkenes, in particular linear C2-C10-1-alkenes such as. ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene or branched C2-C10-1-a. kenes such as 4-methyl-1-pentene, conjugated and unconjugated dienes such as 1,3-butadiene, 1,5-hexadiene or 1,7-octadiene or vinylaromatic compounds such as styrene or substituted sty- rene. It is also possible to polymerize mixtures of various a-olefins. Preference is given to polym- erizing at least one olefin selected from the group consisting of ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene.

Suitable olefins also include ones in which the double bond is part of a cyclic structure which can have one or more ring systems. Examples are cyclopentene, cyclohexene, norbornene, tetracy- clododecene and methylnorbornene and dienes such as 5-ethylidihe-2-norbornene, norbornadi- ene or ethyinorbornadiene.

Mixtures of two or more olefins can also be polymerized. In contrast to some known iron and co- balt complexes, the transition metal complexes of the present invention display a good polymer- zation activity even in the case of higher a-olefins, so that their suitability for copolymerization deserves particular emphasis. In particular, the transition metal complexes of the present inven- tion can be used for the polymerization or copolymerization of ethene or propene. As comono- mers in the polymerization of ethene, preference is given to using C3-C8-a-olefins or norbornene, in particular 1-butene, 1-pentene, 1-hexene and/or 1-octen. Preference is given to using mono- mer mixtures containing at least 50 mol% of ethene. Preferred comonomers in the polymerization of propylene are ethene and/or butene.

The polymerization can be carried out in a known manner in bulk, in suspension, in the gas phase or in a superpritical medium in the customary reactors used for the polymerization of olefins. It can be carried out batchwise or preferably continuously in one or more stages. High-pressure polym- erization processes in tube reactors or autoclaves, solution processes, suspension processes, stirred gas-phase processes or gas-phase fluidized-bed processes are all possible.

The polymerizations are usually carried out at from-60 to 350°C under pressures of from 0.5 to 4 000 bar at mean residence times of from 0.5 to 5 hours, preferably from 0.5 to 3 hours. The advantageous pressure and temperature ranges for carrying out the polymerizations usually de- pend on the polymerization method. In the case of high-pressure polymerization processes, which are usually carried out at pressures of from 1 000 to 4 000 bar, in particular from 2 000 to 3 500 bar, high polymerization temperatures are generally also set. Advantageous temperature ranges for these high-pressure polymerization processes are from 200 to 320°C, in particular from 220 to 290°C. In the case of low-pressure polymerization processes, a temperature which is at least a few degrees below the softening temperature of the polymer is generally set. These polymeriza- tion processes are preferably carried out at from 50 to 180°C, preferably from 70 to 120°C. In the case of suspension polymerization, the polymerization is usually carried out in a suspension me- dium, preferably an inert hydrocarbon such as isobutane or a mixture of hydrocarbons, or else in the monomers themselves. The polymerization temperatures are generally in the range from-20 to 115°C, and the pressure is generally in the range from 1 to 100 bar. The solids content of the suspension is generally in the range from 10 to 80%. The polymerization can be carried out batchwise, e. g. in stirring autoclaves, or continuously, e. g. in tube reactors, preferably in loop reactors. Particular preference is given to employing the Philips PF process as described in US-A 3 242 150 and US-A 3 248 179. The gas-phase polymerization is generally carried out at from 30 to 125°C.

Among the abovementioned polymerization processes, particular preference is given to gas- phase polymerization, in particular in gas-phase fluidized-bed reactors, solution polymerization and suspension polymerization, in particular in loop reactors and stirred tank reactors. The gas- phase polymerization can also be carried out in the condensed or supercondensed phase, in which part of the circulating gas is cooled to below the dew point and is recirculated as a two- phase mixture to the reactor. It is also possible to use a multizone reactor in which two polymer- zation zones are linked to one another and the polymer is passed alternately through these two zones a number of times. The two zones can also have different polymerization conditions. Such a reactor is described, for example, in WO 97/04015. The different or identical polymerization processes can also, if desired, be connected in series so as to form a polymerization cascade, for example in the Hostalen process. A parallel reactor arrangement using two or more identical or different processes is also possible. Furthermore, molar mass regulators, for example hydrogen, or customary additives such as antistatics can also be used in the polymerizations.

The monocyclopentadienyl complexes of the present invention and the catalyst systems in which they are present can also be prepared by means of combinations of methods or their polymeriza- tion activity can be tested with the aid of these combined methods.

The process of the present invention allows polymers of olefins to be prepared. The term"polym- erization"as used here in the description of the present invention encompasses both polymeriza- tion and oligomerization, i. e. oligomers and polymers having molar masses Mw in the range from about 56 to 10 000 000 can be produced by this process.

Owing to their good mechanical properties, the olefin polymers prepared using the catalyst sys- tem of the present invention are particularly useful for the production of films, fibers and molding.

The catalyst systems of the present invention give polymers having molar masses which are lower than those obtained using catalyst systems which do not possess an aryl substituent. In addition, the catalyst systems of the present invention display very high activities.

Examples All syntheses and polymerizations were carried out under a protective nitrogen atmosphere.

The density, [g/cm3] was determined in accordance with ISO 1183.

The Staudinger index (n) [di/g] was determined using an automatic Ubbelohde viscometer (Lauda PVS 1) in decalin as solvent at 130°C (IS01628 at 130°C, 0.001 g/ml of decalin).

The NMR spectra were measured on a Bruker DRX 200 (1H : 200.13 MHz)., n'H-NMR spectra, the signal of the incompletely deuterate. d part of the solvent used served as internal standard. All signals were calibrated to the appropriate literature values.

Mass spectra were recorded on a Finnigan MAT 8230, and high-resolution mass spectra were measured on a Micromass CTD ZAB-2F VH spectrometer.

Abbreviations in the tables below : Cat. catalyst t (poly) polymerization time polymer amount of polymer formed density polymer density prod. productivity of the catalyst system in g of polymer obtained per mmol of catalyst (chromium complex) used per hour hexene whether or not hexene is present during the polymerization

Example 1 1.1. Preparation of 2-methyl-3- (trimethylsilyloxy) cyclopent-2-enone 37.8 g (240 mmol) of hexamethyldisilazane were added to a mixture of 7.8 g (70 mmol) of 2- methylcyclopentane-1, 3-dione and 0. 29 g (4.4 mmol) of imidazole and the mixture was subse- quently heated at 120°C for 2 hours. The mixture was allowed to cool to room temperature while stirring and all volatile components were distilled off. Distillation at 60-63°C and 3x10-3 mbar gave 12.7 g (68 mmol, 98%) of 2-methyl-3- (trimethylsilyloxy) cyclopent-2-enone as a colorless liquid.

NMR'H (200,13 MHZ, Cd13) : 0.26 (9H, s, Me3Si) ; 1.52 (3H, s, Me); 2.47-2. 34 (4H, m, CH2).

NMR 1H (50,1 MHZ, CDCl3) : 0.0 (Me3Si) ; 5.3 (Me); 25.6 (CH2) ; 32.9 (CH2) ; 120.1 (Ca, kene) ; 180. 9 (Calkene-OTMS) ; 205. 9 (C-O).

1.2. Preparation of 2-methyl-3- (8-quinolyl) cyclopent-2-enone A mixture of 38.7 g (186 mmol) of 8-bromoquinoline and 250 ml of tetrahydrofuran was cooled to - 80°C, and 74.4 mi of n-butyllithium (2.5 M in hexane, 186 mmol) were subsequently added while stirring. The mixture was stirred for a further 15 minutes and 49.9 g (186 mmol) of 2-methyl-3- (trimethylsilyloxy) cyclopent-2-enone were added while stirring. The mixture was allowed to warm to room temperature while stirring and stirring was continued for a further one hour. The reaction mixture was then hydrolyzed by means of a mixture of 40 g of ice and 30 mi of concentrated hy- drochloric acid and the mixture obtained in this way was refluxed for 3 hours. The mixture was allowed to cool to room temperature while stirring and ammonia solution was added until a pH of 12 had been reached. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The organic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue obtained in this way was distilled at 119-139°C and 2x10-2 mbar to give 31.1g (139.3 mmol, 74.9%) of 2- methyl-3- (8-quinolyl) cyclopent-2-enohe.

NMR'H (200,13 MHZ, CDCl3) : 1.69 (3H, t, Me); 2.58 (2H, m, CH2) ; 3.12 (2H, m, CH2) ; 7.39 (1H, dd, H3) ; 7.47-7. 60 (2H, m, CHqujnoìyi) ; 7.82 (1H, dd, CHquinolyl) ; 8. 16 (1H, dd, H4) ; 8.87 (1H, dd, H2).

MS (EI), m/e (%): 223 (8) [M+] ; 195 (32) [M+-2CH2] ; 180 (100) [M+-2CH2-CH3].

1.3. Preparation of 3-hydroxy-2-methyl-3-phenyl-1- (8-quinolyl) cyclopentene A mixture of 2.4 9 (10.75 mmol) of 2-methyl-3- (8-quinolyl) cyclopent-2-enone and 100 ml of-tetra- hydrofuran was cooled to-90°C, and 7.2 mi of phenyllithium (1.8 M in cyclohexane/diethyl ether, 12.9 mmol) were subsequently added while stirring. The mixture was stirred for a further one hour at this temperature and 1 ml of ethyl acetate was then added. The mixture was then allowed to warm to room temperature while stirring, refluxed for 10 minutes, cooled to room temperature and 100 mi of water were then added. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The organic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue

was dissolved in 5 ml of toluene and then admixed with 80 ml of hexane. The precipitate formed was filtered dff and dried. This gave 1.874 g (6.22 mmol, 57.9% yield) of 3-hydroxy-2-methyl-3- phenyl-1- (8-quinolyl) cyclopentene.

NMR 1H (200,13 MHZ, CDCl3) : 1.48 (3H, m, Me); 2.57 (2H, m, CH2) ; 2.98 (1H, m, CH2) ; 3.2 (1H, m, CH2) ; 4. 31 (1H, s, OH); 7.39 (1H, dd, H3) ; 7.25-7. 81 (9H, m, CHquìnolyl+phenyl) ; 8. 16 (1H, dd, H4) ; 8.88 (1H, dd, H2).

1.4. Preparation of 2-methyl-3-phenyl-1-(8-quinolyl) cyclopentadiene A mixture of 5 ml of water and 5 mi of concentrated hydrochloric acid was added to a solution of 1.717 g (5.7 mmol) of 3-hydroxy-2-methyl-3-phenyl-1- (8-quinolyl) cyclopentene in 100 ml of tetra- hydrofuran. The mixture was stirred at room temperature for 90 minutes and ammonia solution was then added until a pH of 12 had been reached. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The or- ganic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue obtained in this way was distilled at 157-170°C and 2x10-2 mbar to give 1.12 g (3.95 mmol, 69.3%) of 2-methyl-3-phenyl-1-(8-quinolyl) cyclopentadiene.

NMR'H (200,13 MHZ, CDCl3) : 1.2 (3H, d, Me); 2.01 (3H, m, Me); 2.10 (3H, m, Me) ; 3.65 (2H, m, CH2) ; 3.9 (2H, m'CH2) ; 4.78 (1H, s, CHMe) ; 6.58 (1H, m, CpH); 6.64 (1H, m, CpH); 7.01 (1H, m, CpH) ; 7.03 (1H, m, CpH) ; 7.23-7. 87 (27H, m, CHqujnolyl+phenyl) ; 8.13-8. 22 (3H, m, H4) ; 8. 97-9.05 (3H, m, H2).

1.5. Preparation of (2-methyl-3-phenyl-1- (8-quinolyl) cyclopentadienyl) chromium dichloride A solution of 1. 09. g (3.85 mmol) of 2-methyl-3-phenyl-1-(8-quinolyl)cyclopentadiene in 40 ml of tetrahydrofuran was added to a suspension of 0.157 g (3.85 mmol) of potassium hydride in 20 ml of tetrahydrofuran. After the addition was complete, the reaction mixture was stirred at room tem- perature for 6 hours and was subsequently added to a solution of 1.44 g (3.85 mmol) of chromium trichloride tris (tetrahydrofuran) in 50 ml of tetrahydrofuran while stirring. The mixture was stirred at room temperature for a further 12 hours and the solvent was then distilled off and the residue was

washed 3 times with hexane and 3 times with toluene. The soluble material in the residue ob- tained in this way was taken up in methylene chloride and filtered. The filtrate was freed of sol- vent, washed and dried under reduced pressure. This gave 0.969 g (2.39 mmol) of (2-methyl-3- phenyl-1- (8-quinolyl) cyclopentadienyl) chromium dichloride (62%).

NMR 1H (200,13 MHZ, CDC13) : -53.3 (1H, H4);-16. 5 (1H, Hs7) ; 11.2 (3H, Me); 14.8 (1H, H5) ; 49.4 (1H, H3).

MS (EI), m/e (%): 404 (100) [M+] ; 369 (76) [M+-CI] ; 332; (92) [M+-2HCl] ; 280 (48) [M+-2HC,-Cr].

Example 2 2.1. Preparation of 3-hydroxy-2-methyl-3- (4-benzotrifluoride)-1- (8-quinolyl) cyclopentene A solution of 3.51 g (15.6 mmol) of 4-bromobenzotrifluoride in 80 ml of tetrahydrofuran was cooled to-90°C, and 6.2 ml of n-butyllithium (2.5 M in hexane, 15. 6 mmol) were subsequently added while stirring. After stirring for 15 minutes at this temperature, a solution of 2.9 g (13 mmol) of 2- methyl-3- (8-quinolyl) cyclopent-2-enone (see Example 1. 2) in 40 mi of tetrahydrofuran was added while stirring. The mixture was stirred for a further one hour at this temperature and 1 ml of ethyl acetate was then added. The mixture was then allowed to warm to room temperature while stir- ring and 100 mi of water was subsequently added. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The or- ganic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue was dissolved in 5 ml of toluene and then admixed with 80 ml of hexane: The precipitate formed was filtered off and dried. This gave 2.69 g (7.28 mmol) of 3-hydroxy-3-methyl- 3- (4-benzotrifiuoride)-1- (8-quinolyl) cyclopentene. A second fraction was obtained by cooling the mother liquor (1. 42 g, 3.84 mmol, total yield : 85.4%).

NMR'H (200,13 MHZ, CDC13) : 1.42 (3H, m, Me); 2.52 (2H, m, CH2) ; 2.98 (1H, m, CH2) ; 3.18 (1H, m, CH2) ; 4.10 (1H, s, OH); 7.39 (1 H, dd, H3) ; 7.56-7. 84 (7H, m, CHquinolyl+aryl) ; 8.18 (1H, dd, H4); 8.89 (1 H, dd, H2).

MS (EI), m/e (%): 369 (9) [M+] ; 351 (100) [M+-H2O] ; 336 (12) [M+-H2O-Me] ; 181 (72) [M+-H2O-Me- quinolyl-CH2].

2.2. Preparation of 2-methyl-3- (4-benzotrifluoride)-1- (8-quinolyl) cyclopentadiene A mixture of 5 ml of water and 5 ml of concentrated hydrochloric acid was added to a solution of 3.61 g (9 : 8 mmol) of 3-hydroxy-2-methy !-3- (4-benzotrifluoride)-1- (8-quinolyl) cyclopentene in 100 ml of tetrahydrofuran. The mixture was stirred at room temperature for 90 minutes and am- monia solution was then added until a pH of 12 had been reached. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The organic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue obtained in this way was distilled at 169-176°C and 2x10-2 mbar to give 2.09 g (5.9 mmol, 60. 2%) of 2-methyl-3- (4-benzotrifiuoride)-1- (8-quinolyl) cyclopentadiene.

NMR'H (200, 13 MHZ, CDCl3) : 1.13 (3H, d, Me); 1.97 (3H, m, Me) ; 2.03 (3H, m, Me); 3.62 (2H, m, CH2) ; 3.87 (2H, m, CH2) ; 4. 81 (1H, q, CHMe) ; 6.59 (1H, m, CpH) ; 6.66 (1H, m, CpH); 7.07 (1H, m, CpH); 7.26 (1H, m, CpH); 7.31-7. 88 (24H, m, CHquinolyl+aryl); ; 8. 14-8.24 (3H, m, H4) ; 8.93-9. 02 (3H, m, H2).

MS (El), m/e (%): 351 (100) [M+] ; 167 (72) [M+-F3CC6H4-C3H3].

2.3. Preparation of (2-methyl-3- (4-benzotrifluoride)-1- (8-quinolyl) cyclopentadienyl) chromium di- chloride A solution of 2, 09 g (5.95 mmol) of 2-methyl-3- (4-benzotrifluoride)-1- (8-quinolyl) cyclopentadiene in 40 ml of tetrahydrofuran was added to a suspension of 0.242 g (5.95 mmol) of potassium hy- dride in 20 ml of tetrahydrofuran. After the addition was complete, the reaction mixture was stirred at room temperature for 6 hours and subsequently added to a solution of 2.23 g (5.95 mmol) of chromium trichloride tris (tetrahydrofuran) in 50 ml of tetrahydrofuran while stirring. The mixture was stirred at room temperature for a further 12 hours and the solvent was then distilled off and the residue was washed 3 times with hexane and 3 times with toluene. The residue obtained in this way was extracted 3 times with methylene chloride and filtered off. The combined methylene chloride extracts were freed of solvent, washed and dried under reduced pressure. This gave 1.58 g (3.34 mmol) of (2-methyl-3- (4-benzotrifluoride)-1- (8-quinolyl) cyclopentadienyl) chromium dichloride (56. 1%).

NMR'H (200,13 MHZ, CDC13) :-54. 1 (1H, H4);-17. 1 (1 H, Hs) ; 13.5 (3H, Me); 14.9 (1 H, H6) ; 48.8 (1H, H3).

MS (El), m/e (%) : 472 (100) [M+] ; 437 (82) [M+-Cl] ; 400 (49) [M+-2HC13 ; 380 (22) [M+-2HCl-Cr-HF] ; 348 (23) [M+-2HCl-Cr].

Example 3 (Comparative Example) 3.1. Preparation of 2-methyl-3-pentyf-1- (8-quinolyl) cyclopentadiene A solution of 6.8 g (32 mmol) of 8-bromoquinoline in 90 ml of tetrahydrofuran was cooled to-90°C, and 12.8 ml of n-butyllithium (2.5 M in hexane, 32 mmol) were subsequently added while stirring.

After stirring for 15 minutes at this temperature, 5.3 g (32 mmof) of 2-methyl-3-pentylcyclopent-2- enone (dihydroisojasmone) were added while stirring. The mixture was stirred at this temperature for a further one hour, allowed to warm to room temperature and then refluxed for one hour. After cooling to room temperature, a mixture of 30 g of ice and 30 g of concentrated hydrochloric acid was added and the resulting mixture was refluxed for 2 hours. The mixture was allowed to cool to room temperature while stirring and ammonia solution was added until a pH of 12 had been reached. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The organic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue was dissolved in 5 ml of toluene and then admixed with 80 ml of hexane. The precipitate formed was filtered off and dried.

The residue obtained in this way was distilled at >110°C and 1x10-2 mbar to give 2.6 g of 2- methyl-3-pentyl-1- (8-quinolyl) cyclopentadiene.

3.2. Preparation of (2-methy.-3-penty.-1-(8-quinolyl) cyclopentadienyl) chromium dichloride A solution of 0.5 g (1.81 mmol) of 2-methyl-3-pentyl-1- (8-quinolyl) cyclopentadiene in 20 ml of tetrahydrofuran was added to a suspension of 0.07 g (1.81 mmol) of potassium hydride in 20 ml of tetrahydrofuran. After the addition was complete, the reaction mixture was stirred at room tem- perature for 16 hours and subsequently added to a solution of 0.67 g (1.81 mmol) of chromium trichloride tris (tetrahydrofuran) in 20 ml of tetrahydrofuran while stirring. The mixture was stirred at room temperature for a further 16 hours, and precipitated product was then filtered off and washed twice with hexane. This gave 0.45 g (1.12 mmol) of (2-methyl-3-pentyl-1- (8- quinolyl) cyclopentadienyl) chromium dichloride (62%).

Examples 4-7 Polymerizati6n The polymerizations were carried out at 40°C under argon in a 1 I four-necked flask provided with contact thermometer, stirrer with Teflon blade, heated mantle and gas inlet tube. The appropriate amount of Mao (10% strength solution in toluene, Cr: AI as in Table 1) was added to a solution of the amount indicated in Table 1 of the appropriate complex in 250 ml of toluene and the mixture was heated to 40°C on a water bath.

In the ethylene homopolymerizations, ethylene was passed through the solution at a flow rate of from about 20 to 40 ich at atmospheric pressure. In the case of the ethylene/1-hexene copolymeri- zation, 3 ml of hexene were placed in the flask shortly before addition of ethylene and ethylene was subsequently passed through the mixture at a flow rate of from about 20 to 40./h at atmos- pheric pressure. The remaining amount of hexene (6 ml) was added via a. dropping funnel over a period of 15 minutes. After maintaining a constant ethylene flow for the time indicated in Table 1, the polymerization was stopped by addition of methanolic HCI solution (15 mi of concentrated hydrochloric acid in 50 ml of methanol). 250 mi of methanol were subsequently added and the white polymer formed was filtered off, washed with methanol and dried at 70°C.

Table 1: Polymerization results Ex. Cat. from Amount of cat. Cr:Al t(poly) Hexene Polymer Prod. Eta-value Density Ex. [mg] ([µmol]) [min] [g] [g/(mmol M#h)] [dl/g] [g/cm3] 4 2 13.3 (28.1) 1:500 15 no 13.3 1895 1.08 n.d. 5 3 10.2 (25.8) 1:350 30 no 3.8 738 10.4 0.921 6 2 11.5 (24.3) 1:500 15 yes 13.8 2263 0.79 0.917 7 1 12.1 (29.9) 1:500 15 yes 13.1 1754 0.55 0.909