CA2076775C - Process for the preparation of an olefin polymer - Google Patents

Abstract

A very effective catalyst system for olefin polymeriza-tion consists of a cocatalyst, preferably an aluminoxane, and a metallocene of the formula (I)

Description

C, . t P') P
HOECHST hKTTENGESELLSGHAFT - HOE 91/F 267 ~jr~L~Jl~"~
Description Process for the preparation of an olefin polymer The present invention relates to a process for the preparation of olefin polymers having a narrow molecular weight distribution, variable molecu:Lar weight and, in the case of prochiral monomers, a variable microstructure of the chain.
Polyolefins of high molecular weight are of importance in particular for the production of films, sheets or hollow articles, such as, for example, pipes or moldings.
Polyolefins of low molecular weight are of importance for the preparation of additives or lubricants.
Soluble metallocene compounds based on bis(cyclopentadi-enyl)z~.rconium-alkyl or halide in combination with oligomeric aluminoxanes are known from the literature.
Using these systems, it is possible to polymerize ethyl-ene with a good activity and propylene with a moderate activity. Polyethylene of narrow molecular weight distri-bution and average molecular weight is obtained, and the polypropylene obtained is atactic and has a very low malecular weight.
Isotactic polypropylene is prepared with the aid of ethylene-bis(4,5,6,7~-tetrahydro-1-indenyl)zirconium dichloride together with an aluminoxane in a suspension polymerization (cf. EP-A 185 918). The polymer has a narrow molecular weight distribution. A particular disadvantage of this process is, however, that only polymers of very low molecular weight can be prepared at polymerization temperatures which are of industrial interest.
A specific preactivation method for the metallocene with "~ ~, r~ ;> ;~~ i~j ..:

- 2 ... ~.~ e~ °~ y"'~ a an aluminoxane has also been proposed, this leading to a considerable increase in the activity of the catalyst system and to a significant improvement in the particle morphology of the polymer (cf. DE-OS 37 26 fl~7).
Catalysts based on ethylenebisindenylhafnium dichloride and ethylene-bis(4,5,6,7-tetrahydro-1-indenyl)hafnilun dichloride and methylaluminoxane, with which higher molecular weight polypropylenes can be prepared by suspension polymerization, are furthermore known (cf.
1b J. .Am. Chem. Soc. 1b9 (198?) s5~~). Under polymerization conditions which are relevant in industry, however, the particle morphology of the polymers produced in this way is not satisfactory and the activity of the catalysts employed is comparatively low. Together with the high catalyst costs, an inexpensive polymerization is there-fore impossible using these systems.
The problems mentioned last are solved in principle by using bridged metallocene catalyst systems which carry an a13~y1 or aryl group in the 2-position relative to the bridge on the two aromatic ligands. Such systems are described in ZA 91/8925.
I~owever, the catalysts mentioned last still have certain deficits in their properties or property combinations if a particularly broad applicability for various polymeriz-ation tasks and an industrially and economically :~avor-able procedure is considered. Tn particular, it is desirable - to carry out the polymerization at a high polymeriz ation temperature, for example 7UnC, because the catalyst activity is then high, and less cooling medium is needed to remove the heat of polymeriza-t:i.on than at a low polymerization temperature, ', _ - to be able to produce polyolefins of varying moles ular weights at this high polymerization temperature i without hydrogen having to be used as a molecular y , t~ ~~
-, f:o '9 ~ ~;~ t1,"~ ;; ' weight regulator (the polymers thus produced contain unsaturated end groups which can be used for chem-ical functionalizations), to be able to produce different stereotactia se quence lengths in stereospecific polymerization at this high polymerization temperature, these having the effect, for e~ampla in the case of isotactic polypropylene, of different melting points and other differences in properties, and ° to obtain a morphology of the polymer powder with average particle sizes of > 1000 dam, since process-ing machines can be charged directly with such powders without granulation.
Tt has now been found that these objects can be achiaved using bridged metallocenes which are substituted in a certain manner in the ligand sphere.
The invention thus relates to a process far the prepara-tion of an olefin polymer by polymerization or copolymer--ization of an olefin of the formula R~°CR=CR°Rk, in which R~ and Rb are identical or different and are a hydrogen atom or a hydrocarboza radical having 1 to 14 carbon atoms, or Ra and Rb form a rang with the atoms joining them, at a temperature of -~60 to 200°G, under a pressure of 0.5 to 100 bar, in solution, in suspension or in the gas phase, in the presence of a catalyst which is formed from a metallocene as the transition metal compound and a cocatalyst, which comprises using as the metallocene a compound of the formula T

raa,,-~,7,,,syi~t.., n ~ M 1 Ro Ft7 R 2 .,' dcRa~~)n R (CR~R9 ) m in which P~5' is a metal of group IVb, Vb or VIb of the P~eriadic Table, Ra and Rz~ are identical or different and are hydrogen, a ~1-C1°-alkyl group, a cl-cl°-alkoxy group, a Cs-clo-aryl group, a Cs-CIO-arylaxy group, a C2-cio-alkenyl group, a c~-Cr,o~-arYlalkyl group, a ~~-GGO-alkylaryl group, a Cs-C4o-arylalkenyl group or a halogen atom, R3 and R'' are identical or dif:~erent and are a halageaa atom, a Cl-Clo-alkyl group, which can be halogenated, a c°-C1°°aryl group or an -~RZlo~ _SR1°, -O~1R310~
'giRyo or -PFt2~o radical, in which Rl° ie a halogen atom, a C1-Clo-alkyl group or a CB'Gl°-aryl group, R5 and R6 arQ identical or different and have the meaning mentioned for R'~ and R4, and additionally can also be hydrogen, °

- ~ ~~ ~;~ ~ ~~~ ~~ ~~) R' is i - jJja - MZ . ' ,Hg2 ~ ICR - r O D'12 - , M2 y 13) - O .o i O ' M2 ' a _ ~R11, =AlRll, -GL'-, -Sn-, -O°', -~-, ~~0, =002, -NRalo =C0, lpRxi or ~p ~ C ~ Rai ~
in which 5 R1", R~2 and R13 are identical or differewt and are a hydrogen atom, a halogen atom, a G1-C1o°-alkyl e~roup, a Gl-Clo-fluoroalkyl group, a Cg-Coo--aryl, group, a Go-Gla-f luoroaryl group, a Cl~G~o~alkoxy gxoup, a CZ°Clo~alkenyl group, a C~-G4o-arylalkyl group, a C8-~4o-arylalkenyl group or a C~-C4o-alkylaryl groups Or R2I and Ri2 OX' RI1 and R13 in ed:Ch 6:asE.' form a rinf~
with the atoms joining them, or Rll or R12 with RB or R9 in each case form a rind together with the atoms joining them, MZ is silicon, germanium or tin, R8 and Rs are identical or different and have the meaning mentioned for Rll and m and n are i.denta.ca~. or different and are zero, 1 or 2, m plus n being zero, l or 2.
_ 20 Rlkyl is straight-chaia~ or branched alkyl. FIalogen (halogenated) is fluorine, chlorine, bromine or iodine, preferably fluorine or chlorine.

Y~ ,.
~~.J~~,~~~' r; j -~-The present invention furthermore relates to the poly-olefins prepared by the process described.
The catalyst to be used for the process according to the invention consists of a cocatalyst and a metallocene of the foa4mula I

R (CR8R9 ) m '~~ F~I ~
R2 r (C~28R~) n In formula I, Ml is a metal of group ~Vb, 'vb or Vxb of the Periodic Table, for example titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molyb denum and tungsten, preferably zirconium, hafnium and titanium.
R1 and RZ are identical or different, preferably identi-cal, and are a hydrogen atom, a C1-Czo , preferably C1-C3-alkyl group, a Ci-Clo-, Preferably Cl-C3-alkoxy group, a Cs Coo-, preferably Co-Cg aryl group, a C6-Coo-. Pxef erably CB-Ce-aryloxy group, a C2-Cloy preferably CZ-C~-alkeny:L
group, a C~-C4o-, preferably C~-Clo-arylalkyl group, a C7'~'40'o preferably C~-Ciz-alkylaryl group, a C$-Cko-a preferably Co-C12-arylalkenyl group or a halogen atom, preferably chlorine.
R3 and R4 are identical or different, preferably identi-cal, and axe a halogen atom, preferably a chlorine, bromine or iodine atom, a Cl-C1o-, preferably Cl-Cs-alkyl group, which can be halogenated, a C6-Clo-, preferably C6-Ce-aryl group or an -NRZlo, -SRlo, -OSiR3io I -SiR3~o or -PR2'° radical, in which R'° is a halogen atom, preferably a chlorine atom, or a Cl-Clo-, preferably Cz-C3-alkyl group or a C6-Clo-, Preferably Ce-CB-aryl group.
RS and R6 are identical or differewt, preferably identi-cal, and have the meaning described for R3 and R", with the proviso 'that RS and Rfi may also be hydrogen. RS and Rs are preferably (C1-C4)-alkyl, which can be halogenated, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl or trifluoromethyl, in particular methyl and ethyl.
R' i s R11 R11 R11 R11 R'11 - M2 M2 - _ M2 _ (CR 13) - ~ - Mf .. ~ ~ - b "

R12 R12 R12 g12 X12 i 12 C _ ~ _ 0 _ M _ a = ggl~', sA1R11, -Ge-~, -Sn-, -0°, -S-, aSO, =SO2, ~NRll,, ~CO, =PRll or =P ( 0 ) Rll, in which Ft~l, Rl~ and R13 are identical or different and are a hydrogen atom, a halogen atom, a C~-Clo-, preferably Ca-C4-alkyl group, in particular a methyl group, a Cl-Clo-fluoroalkyl group, preferably a CF3 group, a C6-Czo-, preferably Cs-C8-aryl group, a 'C6-Clo°
fluoroaryl group, preferably a pentafluorophenyl group, a C1-Clo-, preferably C1-C~-alkoxy group, in particular a methoxy group, a CZ-C1o-, preferably CZ-C4-alkenyl group, a C~-C4o , preferably C~-Cio-arylalkyl group, a Ca-C4o-.
preferably Co-Clz-arylalkenyl group or a C~-C4o-, preferably C~-C12-alkylaryl group, or Rll and RlZ or R11 and R13 in each case form a ring together with the atoms joining them, or z i.. ~i ;':j F .:' PYI ~~ ''~ ~ 'r~ YJ ;.~
Rll or Rlx with R° or R9 in each case form a ring together with the atoms joining them Mx is silicon, germanium or tin, preferably silicon and germanium.
R' is preferably =CR~iRlx, =gi.R11R12, =GeR11R1z, _O_, _S_, .SO r ~PRll or =1a ~ i0 ~ R11 a Ra and R9 are identical or different and have the meaning mentioned f or R'1 m and n are identical or different and axe zero, 1 or 2, preferably zero or 1, m plus n being zero, 1 or 2, preferably zero or 1.
The particularly preferred metallocenes are thus the compounds of the formulae ~1., 1B and C

t$>.
(~1°
R$RnC . 1 ' R1 /R R11 ~1/
1 2 S l ~ "-~. R2 R1 1 R1 ~
i E R ~ R6 ~ R i R4 ~ R9 -R
' R1~ ' ~- (C~
. 1 R

i ~- R4 where Ml - Zr, R1 and RZ ~ methyl or chlorine; R~ and R4 methyl, ethyl, n-propyl, i-propyl, n-butyl , i-butyl, tent-butyl or neopentyl; R5 and Rs ~ methyl ar ethyl and Ra, Rg, R~~ end Al~ have the abovementioned meanings, in particular the compounds I mewtioned in the examples.
mhe Chiral metallocenes axe employed as a racemate for the preparation o~ isotactic poly-1-olefins.
~Io~ever, the pure R or s ~~orm can also be used. Optically active polymer can be prepared using these pure s~ereo-isomer forms. However, the meso form of the metallacenes should be separated off, siaace the polymerization-active oenter (the metal atom) is no longer chiral in these compounds because of mirror symmetry on the central metal, and therefore cannot produce a highly iso~actic polymer. ~f the meso form is not separated off, atactic polymer is also formed alongside isotactic polymer. This may be entirely desirable for certain uses - ~or example flexible shaped articles.

.i.. . '~
to ~': i1 '!~ '~ 6" l a ~O w The separation o~ the stereoisomers is k.no=an in princip~.e .
The metallocenes described above can be prepared in accordance 'with the ~o~.loraing equation a H2R' + ~utylLi HR'Li X-((;R'~R~m-l~'°(CR~R~,; ~. _~
r H2R~ + ~utylLi --~ HR°Li HR'°(~r~B~~m R'°(a~rRBR~~n°R~H
~.i~'°(~'r~ef~~ny ~~°(~' Re~~ri ~du (F$8R9C~m ° ~' (R~R9~~m " ~' ~~ R' 7 ~t Rll..l~ RY
~~I , . ~~1 ~~~R9C~n ° ~a ~R R Cs~n ° ~
(Rai~9~,m ° R' I ~ .~' R~L.i~ R' Ma ~2 ~3 X ~ ~I, fir, I, ~-Tosyl; HER' ~ ~H

~. 11 -The preparation processes are known from the literature;
cf. Journal of Organometallic Chem. 288 (1985) 63-67, EP°A 320 762 and the embodiment examples.
The 2 , .4-substituted indenes HzR° and H2Ra used as starting substances can be prepared by 2 different routes.
a) A ketaaldehyde of the formula shown in the equation below, the preparation of which is known (Synthesis 185, 1058), is used as the starting campound.
The reaction of this ketoaldehyde with cyclopentadiene is carried out in an inert solvent in the presence of a base. Alcohols, such as methanol, ethanol or t-butanol, in particular methanol, are preferably used.
A large number of compounds can be used as bases. Rx-amples which may be mentioned are alkali metal and alkaline earth metal hydroxides, alkali metal and alka-line earth metal alcaholates, such as radium methanolate, sodium ethanolate and potassium tart-butanolate, amides, such as lithium diisopropylamide, or amines. Sodium ethanolate, potassium tart°butanolate and potassium hydroxide are preferably used.
The molar ratios of the starting compounds, including the base used, can vary within wide limits. The molar ratio of ketoaldehyde:cyclopentadiene:base is preferably 1:1-1.5x2-3; in particular 1:1.1:2.5.
The reaction temperature is preferably -40°C to 100°C, in particular 0°C-25°C.
The reaction times as a rule vary between 10 minutes and 100 hours, preferably between l hour and 30 hours.
After conversion of the indene which is monosubstituted in the 4-position into the 2-indanone which is monosub-stituted in the 4-position in accordance with general working instructions (Organic Synthesis, Coll. Vol. v, 4'~ ~ ~,v~

1973, 647,, the substituent in the 2-position can be introduced by a Grignard reaction. The subsequent splitting off of water leads to the 2,4-substituted indenes.
The 2,4-substituted indenes are obtained as double bond isomers, which can be employed directly for the synthesis of the corresponding metallocene complexes.
x(3,4) ~(3e4) R(3,4) "a 0 _ 0 /O ~' .\ / ~ / O
~(3r4) .~,.~ ~ ~. o R(5,s) b) Another possible and advantageous strategy proceeds in accordance with the following plan:
A benzyl halide which is substituted in the 2-position is converted, by reaction with an appropriately subst:i.tuted malonic acid diester by a process analogous to a process known from the literature (J. Org. Chem. 1958, 23, :1437 ) , into the disubstituted maloni~ aoid diester.
Hydrolysis of the diester and ~lecarboxylation by customary processes leads to a disubstituted propioni.c acid derivative.
After conversion of the carboxylic acid into the car-boxylic acid chloride, the cyclizat:ion to give the 2,4-w 2Q disubstituted 1-indanone is carried out by customary processes.

Reduction of the ketone by known methods and subsequent splitting off of water gives the 2,4-disubstituted indenes.
R(5,6) COZR

CH2X '~' CO2R OZR ---~
R(_,4) R(3,4) R(5,6) , O
CO2H ~ R(5,6~ R(5r6) ~ (5t6)~ -!~ -..r R(3r4) R R(3,4) R(3.4) According to the invention, the cocatalyst used is preferably an aluminoxane of the formula (II) m ~9a ~,~
~ At -- ~ X41 '-- O At ~ ( I I
~,~ / °o. ~,a P
for the linear type and/or of the formula (III) 6~'a ~ (ICI) _ ~ a.-- ~I
P~2 for the cyclic type, in which, in the formulae (II) and (IIT), the radicals Rlq can be identical or different and are a C1-Ce-alkyl group, a C6-C1g-aryl group or hydro-gen and p is an integer from 2 to 50, preferably 10 tQ J5e i4 -,..
C~.
The radicals R'° are preferably identical and are methyl, isobutyl, phenyl or benzyl, particularly preferably methyl.
If the radicals R14 differ, they are preferably methyl and hydrogen, or alternatively methyl and isobutyl, hydrogen or isobutyl preferably being contained in the compounds to the extent of O.OI-40 ~ (number of radicals R1°).
The alumi.noxane can be prepared in various manners by known processes. One of the methods is, for example, to react an aluminum-hydrocarbon compound and/or a hydrido-aluminum-hydrocarbon compound with water (gaseous, solid, liquid ar bonded - for example as water of crystalliza-tion) in an inert solvent (such as, for example, tolu-ene). To prepare an aluminoxane having different alkyl groups R14, two different aluminum-tr:i.alkyls (A1R3 +
A1R'3), corresponding to the desired composition, are reacted with water (cf. S. Pasynkiewicz, Polyhedron 9 (1990) 429 and EP-A 302 424).
The precise structure of the aluminoxanes II and III is not known.
Regardless of the nature of their preparation, all aluminoxane solutions have the common feature of a varying content of unreacted aluminum starting com~round, which is present in the free dorm or as an adduct.
It is possible for the metallocene to be preactivated with an aluminoxane of the formula (II) and/or (TII) before use in the polymerization reaction. This signifi-cantly increases the polymerization acicivity az~d improves the particle morphology.
The preactivation.of the transition metal compound is carried out in solution. Preferably, for this operation, the metallocene is dissolved in a solution of the :) - 15 ..
aluminoxane in an inert hydrocarbon. An aliphatic or aromatic hydrocarbon is suitable as an inert hydrocarbon.
Toluene is preferably used.
The concentration of the aluminoxane in the solution is in the range from about 1 ~ by weight to the saturation limit, preferably Exam 5 to 30 ~ by weight, in each case based on the total solution. The metallocene can be employed in the same concentration, but it is preferably employed ~.n an amount of lfl-" - 1 mol ;per mole of alumin-oxane. The preactivation time is 5 minutes to 60 hours, preferably 5 to 60 minutes. The preactivation is carried out at a temperature of -78°C to 100°C, preferably 0 to 70°C.
The metallocene can also be prepolymerized or applied to a support. The (or one of the) olefins employed in the polymerization are (or is) preferably used for the prepolymerization.
Suitable supports are, for example, silica eels, aluminum oxides, solid aluminoxane or othex inorganic support materials. A polymer powder in finely divided form is also a suitable support material.
According to the invention, compounds of the formulae R,~Nfh,_X$R' k, R,~~Ii4_R$R' 4, R3C$R',, Or $R' 3 can be Cased as suitable cocatalysts instead of or in addition to an aluminoxane. In these formulae, x is a number Exam 1 to 4, preferably 3, the radicals R are identical or dif ferent, preferably identical, and are Cl-C1o-alDsyl or CB-Cie-aryl, or 2 radicals R form a .ring together with the atom joining them, and the radicals R' are identical or different, preferably identical, and axe C6-C1g-aryl, which can be substituted by alkyl, haloalkyl ar fluorine.
In particular, R is ethyl, propyl, butyl or phenyl, and R' is phenyl, pentafluorophenyl, Pd , ~ ~ ~~ ~~ e~

3,5-bistrifluoromethylphenyl, mesityl, xylyl or tolyl (cf. EP-A 277 003, EP-A-277 004 and EP-A-426 630).
If the abovementioned cocatalysts are used, the actual (active) polymerization catalyst comprises the reaction product of the metallocene and one of the compounds mentioned. This reaction product is therefore preferably prepared first outside the polymerization reactor in a separate step using a suitable solvent (cf. Embodiment Example VIIT).
In principle, any compound which, on the basis of its Lewis acidity, can convert the neutral metallocene into a ration and stabilize it ("labile coordination") is suitable according to the invention as a cocatalyst.
Moreover, the cocatalyst or the anion foamed from it should not. undergo any further reactions with the metallocene canon formed (cf. EP-A X27 697).
Ta remove csitalyst poisons present in tYae alefin, purifi-cation with an aluminum~alkyl, for example AlMe3 or AlEt3, is advantageous. This purification can either be carried out in the polymerization system itself, or the olefin is brought into contact with the Al compound before addition into the polymerization system and is subsequently separated off again.
The polymerization or copolymerization is carried out in a known manner in solution, in suspension or in the gas phase continuously or discontinuously, in one or more stages, at a temperature pf -60 to 200°C, preferably 30 to 80°C. Olefins of the formula R°-CH~CH-Rb are polymer-ized or copolymerized. In this formula, R° and Rb are identical or different and are a hydrogen atom or an alkyl radical having l to 1~ C atoms. However, Re and Rb can also form a ring with the C atoms joining them.
Examples of such olefins axe ethylene, propylene, 1-butene, 1-hexane, 4-methyl-1-pen~tene, 2-octane, 9~D ~~ ~;~ ~ ''.~ ~ pJ
- ~~ -norbornene or norbornadiene. Propylene and ethylene are polymerized in particular.
Hydrogen is added as a molecular weight regulator, if necessary. The total pressure in the polymerization system is 0.5 to 100 bar. Polymerization in the pressure range from 5 to 64 bar, which is of particular industrial interest, is preferred.
The metallocene is used in this polymerization in a concentration, based on the transition metal, of 10x3 to 10-e, preferably 10-G to 10-' mol of transition metal per dm3 of solvent or per dm3 of reactor volume. The aluminox-ane is used in a concentration of 10-5 to 101 mol, prefer-ably 10-'' to 10-2 mol per dm3 of solvent or per dm3 of reactor volume. The other cocatalysts mentioned are used Z5 in amounts which are approximately equimolar to that of the metallocene. In principle, however, higher concentra-tions are also possible.
If the polymerization is carra_ed out as suspension or solution polymerization, an inert solvent customary for ~0 the ~i.egler low pressure process i.s used. For example, the polymerization is carried out in an aliphatic or cycloaliphatic hydrocarbono examples of such solvents whi.ah may be mentioned are propane, butane, pentane, hexane, heptane, isooctane, cyclohexane and methylcyclo-25 hexane. A gasoline or hydrogenated diesel oil fraction can furthermore be used. Toluene can also be used. The polymerization is preferably carried out in the l.i.qui.d manomer.
If inert solvents are used, the monomers are metered in 30 as gases or liquids.
- The polymerization time can be chosen as desired, since the catalyst system to be used according to the invention shows only a slight time-dependent drop i.n polymerization l' ~ '~ ~'p y~ ~.3 ;,~ 1 ~ ~ ~3 v activity.
The prcacess according to the invention is distinguished by the fact that the metallocene catalyst systems de-scribed produce polymers having a narrow molecular weight distribution and coarse particle xnorphalagy as well as variable molecular weight and ster~eotactici,ty in 'the temperature range between 30 and 80°C, which is of industrial interest, but in particular in the range between 60 and 80°C. The particular polymer molecular weight and stereotacticity desired is established by choosing suitable substituents in the 2- and ~-positions of the ligand system of the metallocene. ~f the polymer i~atian is carried out without hydrogen as a molecular weight regulator, the polymers contain unsaturatsed end groups.
The fallawing examples are intended to illustrate the invention in more detail.
In the examples:
57N = viscosity number in cm3/g ~ ~ weight-average molecular weightdetermined in glmol b y g a 1 permeation I~"/Mi, = molecular weight dispersity chromato-graphy m.p. ~ melting point, determined by (20C/minute heating up/cooling rate) TI = isotactic index (II = mm + 1/Z determined mr) by 1~C_N1~IR spectroscopy mmmm = content of isotactic polymer in the 13C-NMR

spectrum in percent BD = polymer bulx density in g/cm3 d5o - average polymer particle diameterin yam ~iFI / (230/5) s melt flow index, measuredin accordance with DIN 53735; in g/10 m inutes ~° '~'j~ i id ~ ~ ~ ~~ r!

Synthesis of the metallocenes used in the examples:
I) Metallocene A: rac-dimethylsilylbis~l-(2-methyl-~-ethylindenyl)}zirconium dichloride I.1. 4-Ethylindene (a2) 20.7 g (181.7 mmol) of 4-oxocaproaldehyde (al, prepared from propionyl chloride and allyl chloride; cf.
Synthesisy (1985) 1058) were dissolved in 10 ml of absolute methanol, and a solution of 13.2 g (199 mmol) of cyclopentadiene in 5 ml of absolute methanol was added, while cooling. This mixture was added dropwise to a solution of 51 g (~54 mmol) of potassium tart-butylate in 100 ml of absolute methanol at 0°C in the course of 35 minutes, during which a dark brown color°ation occurred. After the mixture had been stirred at 0°C for 2-4 hours and at room temperature for a further 2 hours, it was poured onto ice, the pH was brought to 5 and the mixture was extracted with methylene chloride. The organic phase was washed with saturated NaCl solution, dried over sodium sulfate and evaporated. the crude product was chromatographed on 750 g of silica gel 60.
11.1 g (43 ~) of the indene a2 (2 double bond isomers 3:2) could be isolated with hexane/methylene chloride (20:1 to 10:1).
I.2. 4-Ethyl-Z-indanone (a3) 33.9 g (235 mmol) of 4-ethylindene (a2) were slowly added dropwise to a mixture of 141 ml of formic acid (98-100 ~
strength ) and 33 ml ( 34 0 mmol ) of Hz02 ( 35 ~ strength ) , while cooling with ice (highly exothermic reaction). The mixture was then stirred at room temperature for a further 2.5 hours. The yellow-orange suspension formed was freed from excess formic acid under a water pump vacuum. 900 ml of 2 N sulfuric acid were added to the yellow oil which remained. A total of 3 1 of water were bs~ a~ a tin ~,c ,3~ T,~ !~ ~) c='~

distilled over, while topping up with water, the product separating out in the receiver as a yellowish oil. The distillate was neutralized with saturated sodium carbon-ate solution and extracted with ether. The ether phase was dried over sodium sulfate and evaporated. 22.4 g (59 ~) of the compound a3 were obtained as a white solid.
I.3. 2-Methyl-4-ethylindene (a4j 140 ml (420 mmol) of a 3 M ethereal methylmagnesium bromide solution were added to a solution of 22..4 g (140 mmol) of a3 in 500 ml of diethyl ether at room temperature under Ar protection in the course of 1 hour.

The mixture was then stirred under reflux at room temper-ature for another. 2 hours, and was stirred at room temperature for a further 15 hours. The mixture was poured onto ice acidified with H~l, and ex~traated with ether. After the extract had been dried over sodium sulfate, the solvent was stripped off. The yellow oil which rema~i.ned (20.3 g) was taken up in 800 ml of analyt-ical grade toluene, 2>2 g (11.5 mural) of p-toluenesul-Tonic acid hydrate were added and the mixture was re-fluxed far 45 minutes. After cooling, the solution was washed several times with water, dried over sodium sulfate and evaporated. The residue was chromatographed on 620 g of silica gel 60 . 5.5 g (25 ~) of the indene a4 (yellowish oil) could be eluted with hexanelmet9aylene chloride (20:1). Still unused starting material a3 could be recovered with hexane/ethyl acetate (9:1).

I.4. ~imethylsilylbis(2-methyl-4-ethylindene) (a5) 14 ml (34.8 mmol) of a 2.5 M solution of n-butyllithium in hexane were slowly added to a solution of 5.5 g 34 . 8 mmol j of a4 in 30 ml of tetrahydrafuran under Ar protection at 0°G, and the mixture was then heated under reflex for 2 hours. The dark brown solution was then slowly added dropwise to a solution of 2.2 g (17.4 mmol) ~~~'l ~d f of dimethyldichlorosilane in 15 ml of tetrahydrofuran.
The mixture was heated under reflux for a total of hours and stirred overnight at room temperature, and was subsequently poured onto ice and extracted with 5 diethyl ether. The residue which remained after the solvent had been stripped off was chromatographed on 200 g of silica gel. 2.0 g of unused starting material a4 were first eluted with hexane/methylene chloride (20:1 to 10:1). This was followed by 3.1 g of the product a5 (48 ~
I0 yield with respect to Si, 75 ~ with respect to the educt reacted). The compound is obtained as a yellowish oil (2 isomers 3:1).
I.5. rac-Dimethylsilylbis~l-(2-methyl-4--ethylindenyl)~-zircanium dichloride (A) 10 ml ( 25 mmol ) of a 2 . 5 M solution of butyllith:i.um in hexane were added to a solution of 3 .1 g ( 8 . 3 mmol ) of the ligand system a5 in 30 ml of diethyl ether at room temperature under Ar protection. An orange coloration initially occurred, and after 45 minutes the solution became cloudy. After the mixture had been stirred over-night, 10 ml of hexane were added to the now beige-colored suspension and the mixture was filtered over a G3 frit. The precipitate was washed with 20 ml of hexane and dried under an oil pump vacuum for a long period of time.
The virtually colorless powder was added rapidly to a suspension of 1.8 g (7.72 mmol) of zirconium tetrachlor-ide in 30 m1 of methylene chloride at -78°C. The mixture was warmed to room temperature in the course of 1-2 hours and, after stirring at room temperature for 30 minutes, was evaporated completely. The residue was dried under an oil pump vacuum and was first washed with 60 ml of hexane. The product was then isolated by extraction several times with a total of 180 ml of toluene. The _ combined extracts were concentrated and left to crystal lize at --35°C. The first fraction gave 0.76 g of zircono cene A in the pure racemic form (orange-colored - 22 .. ~'~~~~~~~a crystals). The subsequent fractions contained an increasing amount of the meso form. 1.?8 g (43 ~) of compound A were isolated in total . 1~3-NND2 ( CDC13 ) of the racemate: 6.85-7 .55 (m, 6, aromatic Vii) , 6. 80 ( s, 2 "B-Ii) , 2.72 (q,4,CH2), 2.20 (s,6,CH3), 1.30 (t,6,CI~3), 1.2?
(s,6,Si~CIi3), 'H-NM:R (CDC13) of the mesa form: 6.6-7.6 (an,6,aromatic H), 6.68 (s,2,p-H), 2.7 (q,4,C:Dz), 2.48 (s,6,CFh), 1.13-1.43 (m,12,~t~CH3,Si-CH3) .
II. Metallocene B: rac~dimethylsilylbis~l-(2-methyl-4 isopropylindenyl)}zirconium dichloride II.1 4-Isopropylindene (b2) 5-Methyl-4-axocaproaldehyde (b1) was prepared analogously to a1 by reaction of iso-butyryl chloride and allyl chloride ( see I .1. ) . 45 . 6 g ( 356 aaunol ) of b1 were reacted with cyclapentadiene and potassium tart-butylate aaad the mixture was wor%ed up, analogously to instructions I.1.
Column chromatography gave 19.6 g (35 %) of indene b2 as a yellow oil (2 double bond isomers).
II.2. 4-Isopropyl-2~indanone (b3) 33 . 8 g ( 213 anmol ) of compound b2 were oxidized and the product was distilled with water, analogously to instruc-tions I,2. 22.6 g (61 %) of indanone b3 were obtained as a yellowish solid.
II.3, 2-Methyl-4-isopropylindene (b4) 11.1 g (63.8 anmol) of indanone b3 were reacted with 2.5 equivalents of methylmagnesium bromide analogously to instructions I.3. The reaction time was 17 hours at room temperature. The mixture was then refluxed with p-tolu-enesulfonie acid hydrate for 25 minutes. Chramatography gave 3,9 g (36 %) of indene b4 as a colorless ail.

II..4. Dimethylsilylbis(2-methyl-4-isopropylindene) (b5) 3.9 g (22.7 mmol) of indene b4 were reacted with dimeth-yldichlorosilane and the mixture was worked up, analo-gously to instructions I.4. Column chromatograpy gave, in addition to 0.44 g of unused indene, 3.0 g of product b5 as a yellow oil (isomers). The yield was 65 ~ with respect to Si and 73 g with respect to 'the starting material reacted.
II.5. roc-Dimethylsilylbis~(1-(2-methyl-4-isopropylin-denyl)}zirconium dichloride (H) 3.0 g of ligand system b5 were deprotonated and reacted with 1 erluivalent of zirconium tetrachloride in 20 ml of me~thylene chloride, analogously to instructions I.S.
After the crude product had been washed with 40 ml of Z5 hexane, the product was extracted with a fatal of 120 ml of toluene. The toluene extract was evaporated under an oil pump vacuum. I.7 g (46 ~) of the zirconocene were obtained as an orange-colored powder. The racema~te and the meso form were present in a ratio of 1:1. The racemiC
form could be isolated in the pure form by recrys~talliza°
tion from a little toluene or from toluenelhexane mixtures.
~H-NMR of the racemate (CDC13)t 6.7-7.5 (m,6,aromatic-H), 6.85 (s,2,~-H), 3.0 {m,2,i-Pr-GH) 2.23 {s,6,CHa) 1.17-1.37 (d,l2,i-Pr-CH3) 1.27 {s,6,Si-CH3).
1H-NMR of the meso form (CDC13): 6.5-7.5 {m,6,aromatic-H) 6.75 (s,2,~-H) 3.0 (m,2,i-Pr-CH) 2.45 (s,6,CH3) 1.10-1.45 ( m, 18 , i-Pr-CH3, Si-CH3 ) .
III. Metallacene Cs roc-dimethylsilylbis.(1-(2-methyl-4-tent-butylindenyl)~zirconium dichloride III.1. 4-tert-Dutylindene (c2) - Y~~1 ~ ~~ ~~ f1 I~~ t'J
5,5-Dimethyl-4-oxocaproaldehyde c1 was prepared analo-gously to a1 by reaction of pivaloyl chlaride and allyl chloride (see I.1.). 41 g (1~5 mmol) of c1 were reacted with cyclopentadiene and potassium tart-butylate and the mixture was worked up, analogously to instructions I.~.
The reaction time was 19 hours at room temperature.
Column chromatagraphy gave 3.2 g (10 ~) of indene c2 as a yellow oil (2 double bond isomers).
III.2. 4-tart-Dutyl-2-indanone (c3) 8.5 g (49.4 mmol) of compound c2 were oxidized and the product was distilled with water, analogously to instruc-tions I.2. The reaction time was 4 hours at room tempera-ture. 2.8 g (30 ~) of indanone c3 were obtained in the form of yellow crystals.
III.3. 2-°Methyl-4-tart-butylindene (c4) 3.6 g (l9 mmol) of indanane c3 were reacted with 3.0 equivalents of methylmagnesium bromide and the mixture was worked up, analogously to instructions I.3.
The reaction time was 17 hours a~t room temperature and a further 4 hours under reflux. The mixture was then refluxed with p-toluenesulfonic acid hydrate for 25 min-utes. Chromatography gave 1.2 g (33 ~) of indene c4 as a yellow oil. Unused starting material could be recovered with hexaz~e/ethyl acetate (9:1).
TII.4. Dimethyl silylbis ( 2-methyl-4-ter~t-butyl-indene) (c5) 1.2 g (5.4 mmol) of indene c4 were reacted with dimethyl-dichlorosilane and the mixture was worked up, analogously to instructions I.4. The reaction time was 10 hours under reflux and 3 days at room temperature. Column chromato-graphy gave, in addition to 0.48 g of unused indene c4, 0.40 g of product c5 as a yellow oil (isomers). The yield s. r ~ r w .,, ~,~~ ~ ~'v a _ 25 _ was 29 ~ with resgect to 8i and 49 ~ with respect to starting material c4 reacted.
III. S. rac-Dimethylsilylbis{1-(2--methyl-4-tart~butyl-indenyl)}zirconium dichloride (C) S 0.74 ml (1.86 mmol) of a 2.5 M solution of n-butyllithium in hexane saes added to 0.40 g (0.93 mmol) of ligand system c5 in 9 ml of diethyl ether under Ar protection.
After the mixture had been stirred overnight, 'the orange solution was evaporated completely. The residue was dried under an oil pump vacuum for a long time and added rapidly to a suspension of 225 mg (0.96 mmol) of zir-conium tetrachloride in 5 ml of methylene chloride at -78°C. The mixture was stirred at 0°C for 2 hours and at room temperature for 30 minutes and evaporated complete-1y. The product was extracted with a total of 8 ml of toluene. After the toluene had been stripped off, 210 mg (37 ~) of the zirconocene were obtained as an orange powder. The ratio of the racEmate t~ the meso form was 1:1. The pure racemic form could be isolated by recrys--tallization from toluene/hexane. 1~3-NMR of the racemate (CDC13) a 6.8-7.5 (m,6garoznatic-~I) 6.92 (s,2,,e-~I) 2.27 (s,6,CI33) 1.22-2.41 (m,24,t-Bu,Si-CB3) .
iI~-NMIt of the meso form (CDC13) s 6.7-7.6 (m,6,aromatic i~}
6.7 (s,2,p-H) 2.50 (s,6,CH3) I.1-1.5 (m,24,t-Bu,Si~-CTi3).
IV. Metallocene Da rac-methylphenylsilylbis~,fl-(2-methyl-4-isopropyliradenyl)}zirconium dichloride IV. I. Niethylphenylsilylbis(2-methyl-4-isopropyl-indene) (d5) 4.8 ml of a 2.5 ~i solution of butyllithium in hexane were added to a solution of 2.0 g (11.8 mmol) of 2-methyl-4-isopropylindene b4 (see II.3.) in 40 ml of tetrahydro-furan under Ar protection at 0°C, and the mixture was heated under reflex for 90 minutes. The red solution was then added to a solution of 1.12 g (5.9 mmol) of methyl-phenyldichlorosilane in 15 ml of tetrahydrofuran, and the mixture was heated under reflux for 7 hours. Tt was poured onto ice and extracted with ether. The ether phase was dried over sodium sulfate and e~raporated in vacuo.
The residue which remained was chromatographed on 200 g of silica gel 60. 0.57 g of unused indene b4 was first recovered using a mobile phase mixture of hexane/methyl-ene chloride (10:1). 1.2 g of product d5 followed using hexane/methylene chloride (10:2). The yield was 44 ~ with respect to Si and 61 ~s with respect to indene b4 reacted.
IV.2. rac-Methylphenylsilylbis~l-(Z-methyl-4-isopropyl_ indenyl)~zirconium dichloride (D) 3.3 ml (8.3 mmol) of a 2.5 M solution of butyllithium in hexane were slowly added to a solution of 1.28 g (2.76 mmol) of ligand system d5 in 20 ml of diethyl ether at room temperature under Ar protection, and the mixture was stirred overnight. The orange-colored solution was evaporated completely, dried under an oil pump vacuum for a long time and washed with a total of 20 ml of hexane.
The residue was dried under an oil pump vacuLUn at 40°C
for a long time and powdered. The yellow powdex was added to a suspension of 0.62 g (2.66 mmol) of zirconium tetrachloride in I5 ml of methylene ahlorl.de at -78°C.
The mixture was warmed to 0°C in the course of 1 hour and stirred at room temperature for a further 2 hours. The red-brown suspension was evaporated completely and the residue was dried under an oil pump vacuum. 1.05 g (63 ~) of the zirconocene were extracted with toluene (orange powder). 1 racemic and 2 meso forms were present in the crude product in a ratio of 2sl:I. The racemic form could be isolated by recrystallization from taluene/hexan~.
1H-NMR of the isomer mixture (CDC13) : 6.4°8.2 (m,aromatic-H,~9-H) 3.1 (br,i-Pr-CH) 2.55 (s,CH3) 2.33 (s,CH3) 2.22 (s,CA3) 1.95 (s,CH3) 1.13-1.47 (m,i-Pr-CH~,Bi-CH3).

_ 27 _ r:~'~~?r~~t.3 V. Metallocene F: rac-dimethylsilylbis{1-(2-ethyl-4-methylindenyl)).zirconium dichloride V.1. 2-(2-Methylbenzyl)-butyric acid (e1) 14.2 g (0.62 mol) of sodium were dissolved in 250 ml of ethanol, and 118.4 g (0.63 mol) of diethyl ethylmalonate were added. 118.5 g (0.64 mol) of 2-methylbenzyl bromide were added dropwise such that the mixture bailed gently.
The mixture was then heated under reflex for 4 hours. The suspension was poured into water and extracted with ether and the combined organic phases were dried over Mg5~4. The solvent was removed in vacuo and the resulting crude product (187 gj was subsequently reacted without further purification.
For hydrolysis, the product was heated under reflex in Z5 the presence of 139 g of ItQH in 355 m1 of ethanol and 170 ml of HxC for 15 hours. The solvent mixture was stripped off in vacuo, and concentrated hydrochloric acid was added to the residue down to pH 1, while cooling. The mixture was extracted 3 times with ether, and the com-biped organic phases were washed with saturated aqueous NaCl solution and dried over MgSOH. The solvent was removed and the residue was heated to 170°C for decar-boxylation, during which pxoduct e1 distilled off (140-145°C/0.1 mmHgj.
Yield: 96.0 g (81 V.2. 2-(2-methyl-benzyl)-butyryl chloride (e2) 96 g (0.5 mol) of 2-(o-xylyl)-butyric acid (e1) were heated slowly with 89 g (0.75 mol) of SOC12 and the mixture was refluxed until the evolution of gas had ended (1 h). Excess thionyl chloride was distilled off, and _ residues were removed by stripping off in each case 50 ml of toluene three times in vacuo. The crude product was purified by distillation (103°C/1 mmHg).

Yield: 101..7 g (96 ~, 0.48 mol).
V.3. 2-Ethyl-4-methyl-1-indanone (e3) 1.01.7 g (0.48 mol) of 2-(2-methyl-benzyl)-butyryl chlor-ide (e2) were added dropwise to 191 g (1.43 mol) of A1C13 in 600 mI of toluene, and the mixture was heated at 80°C
for about 3.5 hours. The reaction mixture was poured owto 1 I of ice/concentrated HCI, and the phases were separat-ed. The aqueous phase was extracted 4 times with 250 ml of toluene each time, and the combined organic phases were washed with saturated aqueous NaI3C03 solution and NaC1 solution and dried over A~gS04. The solvent was removed in vacuo and the residue was distilled (78°C/0.2 mmHg).
Yield: 81 g (97 ~, 0.464 mmol).
V.4. 2-Ethyl-4-methyl-indene (e4) 11.1. g ( 294 mmol ) of NaBI~,, were added in portions to 34.1 g (196 mmol) of Z-ethyl-4-methyl-1-indanone (e3) in 210 ml of tetrahydrofuran/methanol (2:1), and the mixture was stirred at room temperature for 15 hours. The reac-Lion mixtuxe was poured onto ice, and concentrated ~3CI
was added to pI~ 1. After extraction with ether, the combined organic phases were washed with saturated aqueous Na~IC03 solution and Natal solution and dried over MgS04. The residue (36.2 g) which had been fried from the solvent in vacuo was further reacted directly for the subsequent elimination.
The non-purified 2-ethyl-4~methyl-1-indanol was treated on a steam bath in 700 ml of toluene in the presence of 0.75 g of p-toluenesulfonic acid manohydrate for 2 hours.
The solvent mixture was removed in vacuo, the residue was tal~en up in ether, and the mixture was washed with saturated NaHC03 solution and NaCl solution and dried over Mg504. The solvent was removed an vacuo and the residue ~v~~':~~u - 2g _.
was distilled (62°C/0.2 mmHg).
Yield: 25.7 g {83 ~, 162 mmol).
V.5. Dimethylsilylbis(2-ethyl-4-methylindene) (e5) 26.2 ml (65.6 mmol) of a 2.5 M solution of BuLi in hexane were slowly added dropwise to 10 . 4 g ( 65 . 5 mmol ) of 2-ethyl-4-methyl-indene (e4) in 50 ml of absolute tetrahy-drofuran, and stirring was continued at 50°C for 2 hours.
During this period, 3.95 ml of MezSiCl2 were initially introduced into 50 ml of absolute tetrahydrofuran, and the Li salt was then added dropwise in the course of 8 hours. The mixture was stirred for 15 hours, the solvent was removed in vacuo arid the residue was suspend-ed in n-pentane and filtered off again. After the solvent mixture had been removed, the product was purified by column chromatography over silica gel (n-hexane/CH2C12 9:1).
Yield: 15.1 g (63 ~, 41 mmol).
v.6. rac-Dimethylsilylbis{1-(2-ethyl-4-methylindenyl)}-zirconium dichloride (E) 7 . f 6 ml ( 19 .16 mmol ) of a .2 . 5 M solution of l3uLi in n-hexane wexe added dropwise at room temperature to 3.57 g (9.58 mmol) of MeZSi(Z-Et-4-Me-Ind)2 in 50 ml of tetrahydrofuran, and the mixture was heated at 50°C for a further 3 hours. It was evaporated to dryness, arad the residue was suspended in n-pentane, filtered off and dried. 2.23 g (9.58 mmol) of ZrCI~ were suspended in 150 ml of C1I2C1z and the suspension was cooled to ~-78°C.
The dilithium salt was added, and the mixture was stirred at -20°C for 3 hours and allowed to come to room temperature overnight. The mixture was filtered and the solvent was removed. Crystallization Pram toluene/n-hexane (25:1) gave 0.18 g of orange crystals (meso/rac 5:1). The mother liquor was concentrated to ~a of its volume and left to crystallize at -38°C, to give a d J ~~ '~ ~~ Y6 V ~ e:;j further 0.1 g of the complex mixture. The mother liduor was evaporated to dryness, and the residue waa suspended in n-hexane, filtered off and dried. The pure racemic form of E was obtained as an orange-colored powder.
VI. Metallocene F: tae-dimethylsilylbia~(1-(2,4-dimeth-ylindenyl)~~irconium dichloride VI.1. Methyl (t)-2-methyl-3-hydroxy-3-{2-tolyl)-propionate (fl) 42 g (645 mmol) of Zn in 150 ml of toluene and 50 ml of Ft20 were heated to 80-85°C, and a mixture of 51.6 g (430 mmol) of 2-tolyl-aldehyde and 62 ml (557 mmol) of bromo-2-methyl melon diethylester ~a~ere added drc~pe~ise. AFte~~ 5 ~ of the malonate had been added, the heating was removed and an Iz crystal was added. After vigorous foaming, the remainder was then added dropwise at 80-85°C in the course of 80 minutes, and the mixture was stirred at 85°C
for 2 hours and left to stand overnight.
200 g of ice/30 ml of HZS04 were mixed and poured into the batch. After extraction with ether and washing of the organic phase with NaHC03 solution and NaCI solution, the product was dried and distilled {101°Cl1 mmHg).
Yields 86 g (96 ~) VI.2. Methyl (f)-2-methyl-3-(2-tolyl)-propionate {f2) 132 ml (826 mmol) of HSiEt3 were added to 86 g (413 mmol) of ,~-hydroxy eater f1 in Q00 ml of CA2C1~. 102 ml (826 mmol) of NF3-ether were added in portions at -5 - -10°C
in the course of 5-10 minutes. After 20 haute at room temperature, the mixture was worked up. After hydrolysis with 220 ml of NaHC03 (pH 3), the mixture was extracted with ether, and the organic phase was separated off, washed with NaCl solution, dried and distilled (120°C/1 mmHg).
Yield: 58.9 g (74.1 ~) ~ 11 L=~ i'8 ~~ ~~ ~~ ~ rJ

VI.3. (ø)-2-Methyl-3-(2-tolyl)-propionic acid (f3) 38.45 g (200 mmol) of ester f2, 850 ml of 5 ~ strength NaOH and 850 ml of MeOH were refluxed for 4.5 hours, the MeOH was distilled off, the product was acidified, and the ether extract was dried with Mg a04 and distilled ( 107-109°C/high vacuum).
Yield: 31.8 g (89 VI.4. (-~)-2-Methyl-3-(2--t~lyl)-propionyl chlpride (f4) 7.6.04 g (90 mmol) of acid f3 were heated slowly to 80°C
with 19.6 g (270 mmol) of SOC12 and kept at this tempera-ture until the evolution of gas had ended. To remove the SOC12, the product was evaporated several times with toluene.
Yield: 17.7 g (crude) VI. S. (~)-2,4-Dimethylindanone (f5) 36 g (270 mmol) of A1C13 were added to 17.7 g (90 mmol) of acid chloride f4 in 50 ml of toluene in the course of minutes, and the mixture was stirred at 80°C for 4 hours. It was poured onto ice/HCl, extracted with 20 toluene, washed with H20, NaHC03 solution and NaCI solu-tion, dried and distilled (I09°C/1 mmHg) or chromato_ graphed (n-hexane/ethyl acetate 6:1, rF a 0.44).
Yield: 13.75 g (95.4 ~).
Steps VT.1. to VI.5. were carried out analogously to those in Synth. Comm., 20 (1990) 1387-97.
VI.6. (f)-2,4-Dimethylindanol (f6) 3.55 g (93.9 mmol) of NaBH4 were added in portions to 10.03 g (62.6 mmol) of ketone f5 in 150 ml of tetrahydro-furan/MeOH 2:1 at 0°C in the course of 1 hour. The mixture was stirred at 0°C for 2 hours and then at room ~~ 1 ij a a~ a V7 ,...
- 32 - ~di,~'u ~.3 7 t R.3 temperature overnight. It was poured onto ice/HC1, the pH
was brought to 1, any boric acid (?) which had precipit-ated at the phase boundary was filtered off, the mixture was extracted with Et20, and the extract was washed with NaHCO~ solution and NaCI solution and dried using an oil pump.
Yieldo 10.24 g VT.7. 2,4-Dimethylindene (f7) 10.24 g (62 mmol) of indanol f6 were dissolved in tolu-ene, and 20 mg of p-tolylsulfonic acid hydrate were added. The mixture was left to stand on a steam bath for 2.5 hours, a little water was added, the organic phase was evaporated off and the residue was distilled (133°C/10 mmHg).
Yields 8.63 g (95 VI. B. (f)-Dimethylsilyl-bis(2,4-dimethylindene) (f8) 37»4 ml of a 1.6 M (59<8 mmol) n-HuLi/n-hexane solution were added dropwise to 8.63 g (59.8 mmol) of ligand f7 in 100 ml of Et20, and the mixture was stirred at 40°C for several hours. The Li salt was slowly added dropwise to 3.86 ml (29.9 mmol) of Me2Si.C12 in 30 ml of Ht2~, and the mixture was stirred for 2 hours. After filtration, the filtrate was evaporated and the residue was chromato-graphed (n-hexane/CHZCIz 9 a 1 rF = 0.29 ) . ~'lae product fractions were combined and xecrystallized from MeOH.
Yields 1,25 g (12 ~) VI.9. rac-Dimethylsilylbis.(1-(2,4-dimethylindenyl)}-xirconium dichloride (~') 1.25 g (3.63 mmol) of chelate ligand f8 were dissolved in 20 ml of tetrahydrofuran, 2.9 ml of a 2.5 M (7.26 mmol) n-Huhi/n-hexane salution were added dropwise and the mixture was stirred at -40°C for 2 hours, until the _ 33 -evolution of butane had ended.
0.85 g (3.63 mmol) of zrCl,, was suspended in 30 ml of CI~~C12. After addition of the dilithium salt at -78°C, the mixture was warmed slowly to room temperature, left to stand overnight and filtered. The filtrate was evaporated in vacuo. The complex was obtained an a mixture of the racemic with the meso form in a ratio of 1s1 (orange-col-ored powder). The pure racemic form could be isolated by recrystal2ization from toluene. Pure yield 15 ~s. 'H-NMR
of the racemate (CDC13):6.8-7.5 (m,6,aromatic-H), 6.82 (sr2ef~'H)e 2.3 (s,6,CH3), 2.1 (s,6,CH3), 1.30 (s,6,$i-CH3 ) .
VIT. Metallocene G: rac-dimethy~.silylbis~l-(2°methyl-4--ethylindenyl)}zirconium-dimethyl 1.3 cm3 of a 1.6 M (2.08 mmol) ethereal solution of Me~i were added dropwise to 0.26 g of metallocene A in 40 cm3 of Et2~ at -50°C, and the mixture was stirred at -10°C
for 2 hours. After the solvent had been replaced by n-pentane, the mixture was stirred at room temperature for a further 1.5 hours, and the residue was filtered off and sublimed in vacuo. 0.15 g of sublimate having a correct elemental analysis was obtained.
VI TT . React ion of metallocene G with [ 10u3NH ] [ B ( CsHs ) a l 0.15 g of metallocene G were added to 0.17 g of [Hu3NH] [H(C6H5),,] in 25 cm3 of toluene at 0°C. The mixture was heated to 50°C, while stirring, and stirred at this temperature for 10 minutes. The deep-colored mixture was then evaporated to dryness. An aliqu4t portion of the reaction mixture was used for the polymerization (Bu =
3 0 butt' l ) s Abbreviations: Me ~ methyl, Et = ethyl, Bu ~ butyl, Ind - indenyl.

~~~v~~~~~'~

Polymerization Examples:
Example 1 A dry 16 dm~ reactor was flushed with nitrogen and filled with 10 dm3 of liquid propylene.
30 cm3 of a toluene solution of methylaluminoxane (cor-responding to 45 mmol of Al, average degree of oligomer-ization n - 16) were then added, and the batch was stirred at 30°C for 15 minutes.
In parallel with this, 3.3 mg (0.006 mmol) of metal-locene E were dissolved in 20 cm3 of a toluene solution of methylaluminoxane (30 mmol of Al~ and preactiva'~ed by being left to stand for 15 minutes.
The solution was then introduced into the reacts>r and heated up to the polymerizatian temperature of 70°C
(~°C/minute~ by supplying heat, and the polymerization system was kept at 70°C for 1 hour by cooling. The polymerization was stopped by addition of 20 ml of isopropanol. The excess monomer was gassed off and the polymer was dried in vacuo. 1.44 kg of polypropylene were obtained.
The catalyst activity wes thus 436 kg of PP/g of ~metal~
locene x hour.
VN = 168 cm3/g;
m.p. ~ 149s6°C~ II ~ g5 ~i mmmm a 88.6 ~
HD '- 0030 g/cm3; d5o ~ 2600 ~m r~ = 1. s x log g/mol M° L 2.2 Examples 2-11 The procedure was in each case analogous to Example Z, but the following parameters were varieda ~~ v '~ '~ ~:~

- nature of the metallocene and - amount of the metallocene (mg) - polymerization temperature The polymerization parameters varied and the polymer yield can be seen from Table 1, and the values measured on the polymers can be seen from Table 2.
Table 1 Example Metallocene Polymexizati~anPolymer yield Nature Amount temperature 1o Lm9J C~~l Lk~1 2 B 3.i 6o O.e2 3 B 6.4 50 1.30 4 D 10.1 30 0.75 5 A 4 . 4 7 0 ~, .10 I5 6 A 6.3 50 0.55 7 A ~.i 30 0.25 8 E 3.0 70 0.50 g E 2.7 50 0.26 F 3.0 70 0.72 11 F 30.3 50 0.96 ~'~~~'~'~~
s_ -r --T--r--l--, f 1 i 1 1 i 1 I 1 f 1 1 1 I I I f I I f I f I 1 1 I ! I 1 1 I f 1 I

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i I I I I 1 i 1 1 1 I

1 f I I ' i I 1 f 1 I I
I 1 1w N I N ~ ~ N N N ~
I I 1 1 N 1 i I 1 I f I
I 1 I I 1 I I ! I i f I

1 ~' "- ~ -- n -' 1 't- T T '~ -I-'T T f r .r,1 ~- l a, .n ~n 1 ! ~n u, 1 1 i I I l I

I .-i f o O o I f O O o 1 I f I I I f I

I O I .-i~ ~ 1 1 ~ .-1~ 1 1 i I I 1 1 1 I ~ I X X X I 1 X X X I
1 I 1 I i I I

I \1 ~1 ~1 ~I MI ~,I~.,lNl ~I NI ~I

'~ I I 1 1 1 I t I 1 I
~1 i~t~l utl~t C:l6",1~) Nl r-tE~l ! f f f a I
~ul I m f f t f 1 I ! t I t f i i I 1 f 1 f I f f -1 I I 1 1 i f i ~~ -f -T ' ~ f -~T TT 1 1 i 1 I I i I 1 I t 1 I 1 I
I 1 1 1 I 1 i ! I 1 f I
I i o 1 I o o I o f I 1 f f 1 f t ~ ~ ~
o 1 1 I
I

I I t~ O ~ o o ~
1 1 I 1 f I , tc'1o I o o f ct7I 1 f ~ I 1 i I I
I

I 'O N ~ t~ N M 6~ M i~ ~ ~
1 ~. l I f 1 I I I I 1 i 1 1 I I C ! 1 I 1 I I

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eV t ! f l 1 I f f f 1 I 1 .-1 1 1 1 I ) 1 ! f I S i l a? W 1 t i ! 1 t J 1 1 1 Il i 1 i I I I I ! f l 1 I I I 1 ;Ca I I I I 1 I I 1 I I t 1 iC N M Wit'u7 ~ t~ CO cslo ~i f a "~.~ ;L1' ~~ T~ i~ ej Example 12 The procedure was as in Example I. however, directly after addition of the metallocene to the reactor, 0.s bar of hydrogen was also forced into the reactor. 1.00 kg of polymer were obtained.
Vn = 76 cm3/g#
m.p.: - 198.9°C~
BD = 0.20 g/cm3; d5o = 1500 ~sm 1~, -.°- 6.2x10° glmol IO P~"/bSn = 2.8 Example 13 A dry I6 dm3 reactor was flushed with nitrogen and :Filled with IO dm3 of liquid propylene.
2.5 cm~ of reaction mixture according to Example VIII
I5 (corresponding to 15 mg of metallocene C) were then dissolved in 20 cm3 of toluene and the solution was introduced into the reactor at ambient temperature. The reactor was heated up to the polymerization temperature of 70°C (4°C/minute) by supplying heat, and the polymer 20 9.zation system was kept at 70°C for 1 hour by cooling.
The polymerization was stopped by addition of 20 ml of isopropanol. The excess monomer was gassed off and the polymer was dried in vacuo. 0.8 kg of polypropylene was obtained.
25 VN = 120 cm3/g, m.p.: 144.8°C.
Example 14 A dry 70 dm3 reactor was flushed with nitrogen and filled with 40 dm3 of liquid propylene.
180 cm3 of a toluene solution of methylaluminoxane (cor 30 responding to 270 mmol of A1, average degree of oligomer ization n = 16 ) were then added and the batch was stirred at 30°C for I5 minutes. 35 g of ethy~.ene were then metered in. In parallel with this, 10.9 mg of metal locene A were dissolved in 20 cm3 of a toluene solution 35 of methylaluminoxane (30 mmol of A1) and preactivated by being left to stand for 15 minutes.

ti a i~~~~~°~'~':

The solution was then introduced into the reactor, and the reactor was heated up to the polymerization tempera-ture of 50°C in the course of 10 minutes by supplying heat, and %ept at this temperature for 4 hours, while stirring. During the said ~ hours, a further 85 g of ethylene were metered in continuously. The polymerization was then stopped by addition of 20 ml of isopropanol, the excess monomer was gassed off and the polymer was dried in vacuo. 3.5 kg of random propylenelethylene copolymer having aSn ethylene content of 3.4 ~ by weight were obtained.
VN = 226 cm3/g; 1~3F, = 2.3 x lay g/mol; T~,,IM" = 1.9 example 15 .~ dry 16 dm3 reactor was flushed with nitrogen and :Filled at 20°C with 10 dm3 of a dearomatized gasoline fraction having a boiling range of 200 - 120°C.
The gas space of the vessel was then flushed free from nitrogen by forcing in 2 bar of ethylene and letting down 5 times.
30 cm3 of a toluene solution of methylaluminoxane (cor-xesponding to 45 mmol of AI, molecular weight according to cryoscopic determination 750 g/mol) were then added.
The reactor contents were heated up to 90°C in the course of 15 minutes, while starring, and the overall pressure was brought to 5 bar by addition of ethylene at a stirr-ing speed of 250 revalutions per minute.
rn para12e1 with 'this, 2.~ mg of metallocene C were dissolved in 20 em3 of a toluene solution of methylalum-inoxane and preaati,vated by being left to stand for 15 minutes. The solution was then introduced into the reactor, and the polymerization system was brought to a temperature of 70°C and kept at this temperature for 1 hour by appropriate cooling. The overall pressure ~z~~~'~'~r 3g during this time was kept at 5 bar by appropriate addi-tion of ethylene.
'the polymerization was stopped by addition of 20 ml of isopropanol, and the polymer was filtered off and dried in vacuo.
1.3 kg of polyethylene were obtained.
STN = 542 cm3/g

Claims (12)

1. A metallocene of the formula I
in which M1 is a metal of group IVb, Vb or VIb of the Periodic Table, R1 and R2 are identical or different and are hydrogen, a C1-C10-alkyl group, a C1-C10-alkoxy group, a C6-C10-aryl group, a C6-C10-aryloxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C7-C40-alkylaryl group, a C8-C40-arylalkenyl group or a halogen atom, R3 and R4 are identical or different and are a halogen atom, a C1-C10-alkyl group, which can be halogenated, a C6-C10-aryl group or an -NR2 10, -SR10, -OSiR3 10, -SiR3 10 or -PR2 10 radical, in which R10 is a halogen atom, a C1-C10-alkyl group or a C6-C10-aryl group, R5 and R6 are identical or different and have the meaning mentioned for R3 and R4, and additionally can also be hydrogen, R7 is =BR11, -A1R11, -Ge-, -Sn-, -O-, -S-, =SO, =SO2, =NR11, =CO, =PR11 or =P(O)R11, in which R11, R12 and R13 are identical or different and are a hydrogen atom, a halogen atom, a C1-C10-alkyl group, a C1-C10-fluoroalkyl group, a C6-C10-aryl group, C6-C10-fluoroaryl group, a C1-C10-alkoxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C8-C40-arylalkenyl group or a C7-C40-alkylaryl group, or R11 and R12 or R11 and R13 in each case form a ring with the atoms joining them, or R11 or R12 with R8 or R9 in each case form a ring together with the atoms joining them, M2 is silicon, germanium or tin, R8 and R9 are identical or different and have the meaning mentioned for R11 and m and n are identical or different and are zero, 1 or 2, m plus n being zero, 1 or 2.

2. The metallocene as claimed in claim 1, wherein, in formula I, M1 is Zr, R1 and R2 are identical or different and are methyl or chlorine, R3 and R4 are identical or different and are methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl or neopentyl, R5 and R6 are identical or different and are methyl or ethyl, R7 is a radical and n plus m is zero or 1.

3. The metallocene as claimed in claim 1 or 2, wherein, in formula I, the substituents R1 and R2, R3 and R4, and R5 and R6 are in each case identical.

4. The metallocene as claimed in claim 1 which is rac-dimethylsilylbis(1-(2-methyl-4-ethyl-indenyl)) zirconimu dichloride, rac-dimethylsilylbis(1-(2-methyl-4-isopropylindenyl))zirconium dichloride, rac-dimethylsilyl-bis(1-(2-methyl-4-tert-butylindenyl)) zirconium dichloride, rac-methyl-phenylsilylbis(1-(2-methyl-4isopropylindenyl)) zirconium dichloride, rac-dimethylsilylbis(1-(2-ethyl-4-methylindenyl)) zirconium dichloride, rac-dimethyl-silylbis(1-(2,4-dimethylindenyl))zirconium dichloride or rac-dimethylsilylbis(1-(2-methyl-4-ethyl-indenyl)) zirconium dimethyl.

5. A catalyst which is formed from a metallocene of the formula I as claimed in any one of claims 1 to 4 and a cocatalyst.

6. The catalyst as claimed in claim 5, wherein the cocatalyst is an aluminoxane of the formula (II) for the linear type and/or of the formula (III) for the cyclic type, in which, in the formulae (II) and (III), the radicals R14 are identical or different and are a C1-C6-alkyl group, a C6-C18-aryl group or hydrogen and p is an integer from 2 to 50.

7. The catalyst as claimed in claims 5 or 6, wherein the cocatalyst used is methylaluminoxane.

8. The catalyst as claimed in any one of claims 5-7, wherein the metallocene is applied to a support.

9. The catalyst as claimed in any one of claims 5-8, wherein the metallocene is prepolymerized.

10. A process for the preparation of an olefin polymer by polymerization or copolymerization of an olefin of the formula R a-CH=CH-R b, in which R a and R b are identical or different and are a hydrogen atom or a hydrocarbon radical having 1 to 14 carbon atoms, or R a and R b form a ring with the atoms joining them, at a temperature of -60 to 200°C, under a pressure of 0.5 to 100 bar, in solution, in suspension or in gas phase, in the presence of a catalyst as claimed in any one of claims to 9.

11. The process as claimed in claim 10, wherein ethylene or propylene is polymerized.

12. The process as claimed in claim 10 or 11, wherein the metallocene of the formula I is preactivated with an aluminoxane of the formula II and/or III before the polymerization reaction.