WO1997042151A1

WO1997042151A1 - Cyclopentadiene compound substituted by chiral groups

Info

Publication number: WO1997042151A1
Application number: PCT/NL1997/000236
Authority: WO
Inventors: Gerardus Johannes Maria Gruter; Johannes Antonius Maria Van Beek; Johannes Gerardus De Vries
Original assignee: Dsm N.V.
Priority date: 1996-05-03
Filing date: 1997-04-29
Publication date: 1997-11-13
Also published as: AU2411297A; NL1003015C2

Abstract

Substituted cyclopentadiene compound comprising at least one chiral atom which is not bonded directly to the cyclopentadiene and in which optionally a substituent of the form RDR'n is present, where R is a bonding group between the cyclopentadiene and the DR' group, D is a hetero atom chosen from group 15 or 16 of the Periodic System of the Elements, R' is a substituent and n is the number of R' groups bonded to D, and a metal complex in which such a cyclopentadiene compound is present as a ligand.

Description

CYCLOPENTADIENE COMPOUND SUBSTITUTED BY CHIRAL GROUPS

The invention relates to a substituted cyclopentadiene compound.

Cyclopentadiene compounds, both substituted and unsubstituted, are used widely as a starting material for preparing ligands in metal complexes having catalytic activity. In J. of Organomet. Chem., 479 (1994), 1-29 an overview is provided of the influence of the substituents on cyclopentadiene as a ligand in metal complexes. Here it is observed, on the one hand, that the chemical and physical properties of metal complexes can be varied over a wide range by the specific choice of the substituents on the cyclopentadiene ring. On the other hand, it is stated that no predictions can be made concerning the effect to be expected of specific substituents. In the great majority of cases, either unsubstituted cyclopentadiene or cyclopentadiene substituted by one to five methyl groups is used.

Hereinafter, cyclopentadiene will be abbreviated as Cp. The same abbreviation will be used for a cyclopentadienyl group if it is clear, from the context, whether cyclopentadiene itself or its anion is meant.

From O-A-92/12112 substituted Cp compounds comprising a chiral carbon atom are known. Used as a ligand in a metal complex having a catalytic effect in olefin polymerization, these Cp compounds confer upon such a complex the property of stereoselective polymerization. In WO-A-92/12112, fulvene is started from for the preparation of chiral compounds. A drawback of that method is that in all cases fulvene has to be started from and that the chiral C atom is always an atom that is bonded directly to the Cp. Further, said publication does not teach how optionally several chiral atoms or C atoms not directly bonded to the Cp can be applied. Since stereoselective olefin polymerization is an attractive option in the preparation of olefins with interesting properties, there is a need for other Cp compounds with a chiral atom besides the known ones.

The invention now provides substituted Cp compounds comprising a chiral atom that can also be of a nature other than obtainable with the known process. The substituted Cp compound preferably comprises at least two chiral atoms.

Compared with the Cp compounds according to the state of the art, the presence of at least two such chiral atoms considerably widens the possibility of influencing the stereoselectivity of metal complexes in the polymerization of olefins.

The chiral atoms can be bonded directly to the Cp, but can also be separated from it by one or more C atoms or hetero atoms chosen from groups 14-15 of the Periodic System. The chiral atom itself can also be such a hetero atom. If one chiral atom is present in the Cp compound, it is not bonded directly to the Cp in the compound according to the invention.

For the Periodic System, see the new IUPAC notation to be found on the inside of the cover of the Handbook of Chemistry and Physics, 70th Edition, 1989/1990.

Besides at least one substituent comprising a chiral atom, whose presence is required within the scope of the invention, the Cp compound may also contain further substituents. Ex^amples of these are alkyl groups, linear as well as branched and cyclic, alkenyl and aralkyl groups. It is also possible for these to contain, apart from carbon and hydrogen, one or more hetero atoms from groups 14-17 of the Periodic System of the Elements, for example 0, N, Si or F, a hetero atom not being bound directly to the Cp. Examples of suitable groups are methyl, ethyl, (iso)propyl, sec-butyl, -pentyl, -hexyl and -octyl, (tert-)butyl and higher homologues, cyclohexyl, benzyl. The Cp compound may also be a heterocyclopentadiene compound. Here and hereinafter the term heterocyclopentadiene compound refers to a compound which is derived from cyclopentadiene but in which at least one of the C atoms in the 5-ring thereof has been replaced by a hetero atom, while the hetero atom can be selected from group 14, 15 or 16 of the Periodic System of the Elements. If more than one hetero atom is present in the 5-ring, these hetero atoms can be either identical or different. More preferably, the hetero atom is selected from group 15, especially preferably the hetero atom is phosphorus. As already observed, no process of wider applicability is known for the preparation of Cp compounds comprising a chiral atom. The invention consequently also provides a process for the preparation of substituted Cp compounds comprising at least one chiral atom. This process comprises the reacting of a halide of a substituting compound in a mixture of the Cp compound and an aqueous solution of a base in the presence of a phase transfer catalyst. The term Cp compounds here refers to Cp itself and Cp already substituted in 1 to 4 positions, with the option of two substituents forming a closed ring. By means of the process according to the invention it is thus possible to convert unsubstituted compounds into singly or multiply substituted ones, but it is also possible for mono- or polysubstituted compounds derived from Cp to be substituted further, ring closure also being included in the options.

Preferably, a virtually equivalent quantity of the halogenated substituting compoudn with respect to the Cp compound is used. An equivalent quantity is understood as a quantity in moles which corresponds to the desired substitution multiplicity, for example 2 mol per mole of Cp compound, if disubstitution with the substituent in question is intended.

Depending on the size and the associated steric hindrance of the compounds to be substituted it is possible to obtain t isubstituted to pentasubstituted Cp compounds. If a reaction with a tertiary halide of a substituting compound is carried out, as a rule only trisubstituted Cp compounds can be obtained, whereas with a primary and secondary halide of a substituting compound it is generally possible to achieved tetra and often even pentasubstitution.

By means of this process it is thus possible to obtain Cp compounds that are disubstituted or polysubstituted by the desired chiral substituent and, optionally, in any remaining free positions additionally by other groups.

The substituting compounds are used in the process in the form of their halides and more preferably in the form of their bromides. If bromides are used a smaller quantity of phase transfer catalyst is found to be sufficient, and a higher yield of the compound aimed for is found to be achieved.

In the process according to the invention the desired chiral group can first be synthesized separately and than substituted on the Cp in a suitable halogenated form. It is also possible first to substitute a simpler group on the Cp and then convert that group into the desired chiral group. Since successive substituents are incorporated in certain preference configurations, owing to steric effects for instance, the process according to the invention also allows controlling the position of the chiral atom by means of the sequence of applying the various substituents. Thus optionally the positions at which the chiral atom is not wanted can be blocked by first substituting other groups on those positions. These should be groups which have no significant effect on the intended chiral-atom-related properties of the Cp compound as a ligand in a metal complex. Short linear alkyl substituents are in general the most suitable for this purpose.

By means of this process it is also possible, without intermediate isolation or purification, to obtain Cp compounds which are substituted by specific combinations of substituents. Thus, for example, disubstitution with the aid of a certain halide of a substituting compound can first be carried out and in the same reaction mixture a third substitution can be carried out with a different substituent, by adding a second, different halide of a substituting compound to the mixture after a certain time. This can be repeated, so that it is also possible to prepare Cp derivatives having three or more different substituents.

The substitution takes place at atmospheric or elevated pressure, for instance up to 100 MPa, which higher level is applied in particular if volatile components are present. The temperature at which the reaction takes place may vary within wide limits, for instance from -20 to 120°C, preferably between 10 and 50°C. Starting up the reaction at room temperature is usually a suitable step, after which the temperature of the reaction mixture can rise due to the heat released in the reactions.

The substitution takes place in a mixture of the Cp compound and an aqueous solution of a base. The concentration of the base in the solution is in the range between 20 and 80 wt.%. Hydroxides of an alkali metal, for example K or Na are highly suitable as a base. The base is present in an amount of 5-60 mol per mole of Cp compound, preferably, in an amoutn of 6-30 mol/mol Cp compound and most preferably in an amoutn of 7-13 mol/mol Cp compounds. The substitution takes place in the presence of a phase transfer catalyst which is able to transfer OH-ions from the aqueous phase to the organic phase containing Cp compound and halide, the OH-ions reacting in the organic phase with a H-atom which can be split off the Cp compound. Possible phase transfer catalysts to be used are quaternary ammonium, phosphonium, arsonium, stibonium, bismuthonium, and tertiary sulphonium salts. More preferably, ammonium and phosphonium salts are used, for example tricaprylmethylammonium chloride, commercially available under the name Aliquat 336 (Fluka AG, Switzerland; General Mills Co., USA) and Adogen 464 (Aldrich Chemical Co., USA). Compounds such as benzyltriethylammonium chloride (TEBA) or benzyltriethylammonium bromide (TEBA-Br), benzyltrimethylammonium chloride, benzyltrimethylammonium bromide or benzyltrimethyl¬ ammonium hydroxide (Triton B), tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butyl- ammonium iodide, tetra-n-butylammonium hydrogen sulphate or tetra-n-butylammonium hydroxide and cetylt imethylammonium bromide or cetyltrimethylammonium chloride, benzyltributyl-, tetra-n-pentyl-, tetra-n-hexyl- and trioctylpropylammonium chlorides and their bromides are likewise suitable. Usable phosphonium salts include, for example, tributylhexadecylphosphonium bromide, ethyltriphenylphosphoniu bromide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium iodide and tetrabutyl- phosphonium chloride. Crown ethers and cryptands can also be used as a phase transfer catalyst, for example 15-crown-5, 18-crown-6, dibenzo-18-crown-6, dicyclohexano-18-crown-6, 4,7,13,16,21-pentaoxa-l,10- diazabicyclo[8.8.5]tricosane (Kryptofix 221), 4,7,13,18-tetraoxa-l,10-diazabicyclo[8.5.5]eicosane (Kryptofix 211) and 4,7,13,16,21,24-hexaoxa-l,10- diazabicyclo[8.8.8]-hexacosane ("[2.2.2]") and its benzo derivative Kryptofix 222 B. Polyethers such as ethers of ethylene glycols can also be used as a phase transfer catalyst. Quaternary ammonium salts, phosphonium salts, phosphoric acid triamides, crown ethers, polyethers and cryptands can also be used on supports such as, for example, on a crosslinked poly¬ styrene or another polymer. The phase transfer catalysts are used in an amount of 0.01 - 2, preferably 0.05 - 1 equivalents on the basis of the amount of Cp- compound.

In the implementation of the process the components can be added to the reactor in various sequences. Substituted Cp compounds comprising a chiral atom which can be substituted on the Cp-compound are for instance 1,3-di-( 'branched alkyl ')Cp, where the 'branched alkyl' is for instance 2-butyl, 2 pentyl, 2- hexyl and higher homologues, 3-hexyl , 3-heptyl and higher homologues, 4-octyl, 4-nonyl and higher homologues, 2-(3-methylpentyl) , 2-(3-ethylpentyl) . Examples of Cp compounds substituted by tertiary alkyl groups and comprising a chiral C atom are l,3-di(l- methyl-1-ethyl 'alkyl ')Cp, where 'alkyl' is butyl, pentyl, hexyl, heptyl and higher homologues.

After the reaction is complete, the aqueous phase and the organic phase which contains the Cp compound are separated. When necessary, the Cp compound is recovered from the organic phase by fractional distillation.

The above-described process can be used to obtain Cp compounds bi-, tri-, tetra- and pentasubstituted by the desired branched alkyl.

The substituted Cp compounds according to the invention are particularly suitable as a ligand in a metal complex, and the invention therefore also relates to a metal complex comprising as ligand a substituted cyclopentadiene compound in which at least one and preferably two chiral atoms is/are present. When used as catalyst component in the polymerization of olefins, these metal complexes appear to result in stereoselective catalysts.

Metal complexes which are catalytically active if one of their ligands is a compound according to the invention are complexes of metals from groups 4- 10 of the Periodic System of the Elements and rare earths. In this context, complexes of metals from groups 4 and 5 are preferably used as a catalyst component for polymerizing olefins, complexes of metals from groups 6 and 7 in addition also for metathesis and ring-opening metathesis polymerizations, and complexes of metals from groups 8-10 for olefin copolyme izations with polar comonomers, hydrogenations and carbon lations.

Particularly suitable for the polymerization of olefins are such metal complexes in which the metal is chosen from the group consisting of Ti, Zr, Hf, V and Cr.

The synthesis of metal complexes containing the above-described specific Cp compounds as a ligand in polar and other solvents may take place according to the methods known per se for this purpose. The use of these Cp compounds does not require any adaptations of said known methods.

Further it was found that if at least one substituent of the form -RDR'_n is present on the Cp compound, where R is a bonding group between the Cp and the DR'_n group, D is a hetero atom chosen from group 15 or 16 of the Periodic System of the Elements, R' is a substituent and n is the number of R' groups bonded to D, in a substituted Cp compound in which at least one of the other substituents comprises a chiral atom, the use of that Cp compound as a ligand in a metal complex results in a complex which, when used as a catalyst component in the polymerization of α-olefins, besides enhanced stereoselectivity shows a higher activity than when the group of the form RDR'_n is not present. Corresponding complexes in which the Cp compound has not been substituted as described in the foregoing, appear to be unstable or, if they have been stabilized in another way, to yield less active catalysts than the complexes with substituted Cp compounds according to the invention, in particular in the polyme ization of α-olefins.

Further it appears that the Cp compounds according to the invention can stabilize highly reactive intermediates such as organometal hydrides, organometal boron hydrides, organometal alkyls and organometal kations. Moreover, the metal complexes comprising a Cp compound according to the invention appear to be suitable as stable and volatile precursors for use in metal chemical vapour deposition.

The invention therefore also relates to Cp compounds thus substituted. A supplementary advantage of the presence of such a group is that it may also contain chiral atoms. In particular the R group in it can be of a chiral nature, so that a completely new class of chirally substituted Cp compounds becomes available.

In the RDR'_n group the R group constitutes the bond between the Cp and the DR'_n group. The length of the shortest bond between the Cp and D is critical in that, if the Cp compound is used as a ligand in a metal complex, it determines the accessibility of the metal to the DR'_n group, a factor which facilitates the desired intramolecular coordination. If the R group (or bridge) is too short, the DR'_n group may not be able to coordinate properly owing to ring tension. R is at least one atom long.

The R' groups can each separately be a hydrocarbon radical with 1-20 carbon atoms (such as alkyl, aryl, aralkyl, etc.). Examples of such hydrocarbon radicals are methyl, ethyl, propyl, butyl, hexyl, decyl, phenyl, benzyl and p-tolyl. R' can also be a substituent which, in addition to or instead of carbon and/or hydrogen, comprises one or more hetero atoms from groups 14-16 of the Periodic System of the Elements. Thus a substituent can be a group comprising N, 0 and/or Si. R' should not be a cyclopentadienyl or a cyclopentadienyl-based group. The R group can be a hydrocarbon group with

1-20 carbon atoms (such as alkylidene, arylidene, arylalkylidene, etc.). Examples of such groups are methylene, ethylene, propylene, butylene, phenylene, with or without a substituted side chain. The R group preferably has the following structure:

where p = 1-4 and E represents an atom from group 14 of the Periodic System. The R² groups can each be H or a group as defined for R'.

Thus the main chain of the R group can also comprise silicon or germanium besides carbon. Examples of such R groups are: dialkyl silylene, dialkyl germylene, tetra-alkyl disilylene or dialkyl silaethylene (-(CH₂) (SiR² ₂)~) . The alkyl groups (R²) in such a group preferably have 1 to 4 carbon atoms and more preferably are a methyl or ethyl group. Examples of R groups in which a chiral atom is present are those in which R is a 1- or 2-alkylethyl.

The DR'_n group comprises a heteroatom D chosen from group 15 or 16 of the Periodic System of - l i ¬

the Elements and one or more substituents R' bound to D. The number of R' groups (n) is coupled to the nature of the hetero atom D, in the sense that n = 2 if D originates from group 15 and that n = 1 if D originates from group 16. Preferably, the hetero atom D is chosen from the group comprising nitrogen (N) , oxygen (0), phosphorus (P) or sulphur (S); more prefer¬ ably, the hetero atom is nitrogen (N). The R' group is also preferably an alkyl, more preferably an n-alkyl group containing 1 - 20 C atoms. More preferably, the R' group is an n-alkyl containing 1 - 10 C atoms. Another possibility is that two R' groups in the DR'_n group are joined to each other to form a ring-type structure (so that the DR'_n group may be a pyrrolidinyl group) .

The DR '_n group may bond coordinatively to a metal. If the Cp compound thus substituted is a ligand in a metal complex, the D atom can also be of a chiral nature. This is the case for instance if several R' groups that are different from each other are present.

A group of the form -RDR'_n may be substituted on the Cp compound, optionally already substituted with a group containing at least one chiral atom and with any other groups, for instance via the following synthesis route.

In a first step of this route a substituted Cp compound is deprotonated by reaction with a base, sodium or potassium.

As base can be applied for instance organolithium compounds (R³Li) or organomagnesium compounds (R³MgX), where R³ is an alkyl, aryl, or aralkyl group and X is a halide, such as for instance n-butyl lithium or i-propylmagnesium chloride. Potassium hydride, sodium hydride, inorganic bases, such as NaOH and KOH, and alcoholates of Li, K and Na can also be used as base. Mixtures of the above-mentioned compounds can also be used .

This reaction can be carried out in a polar dispersing agent, such as for instance an ether. Examples of ethers are tetrahydrofuran (THF) and dibutyl ether. Nonpolar solvents, such as for instance toluene, can also be used.

Next, in a second step of the synthesis route the cyclopentadienyl anion obtained reacts with a compound of the formula (R'_nD-R-Y) or (X-R-Sul), where D, R, R' and n are as defined in the foregoing, Y is a halogen atom or a sulphonyl group (Sul). The halogen atom may be chlorine, bromine and iodine. The halogen atom X preferably is a chlorine or bromine atom. The sulphonyl group has the form -OS0₂R⁶, wherein R⁶ is a hydrocarbon radical containing 1 - 20 carbon atoms, such as alkyl, aryl, aralkyl. Examples of such hydrocarbon radicals are butane, pentane, hexane, benzene and naphthalene. R⁶ may also contain one or more hetero atoms from group 14 - 17 of the Periodic System of the Elements, such as N, 0, Si or F, in addition to or instead of carbon and/or hydrogen. Examples of sulphonyl groups are: phenylmethanesulphonyl , benzenesulphonyl, 1-butanesulphonyl , 2 , 5-dichlorobenzenesulphonyl , 5-dimethylamino-l-naphthalenesulphonyl , pentafluoro- benzenesulphonyl , p-toluenesulphonyl , trichloromethane- sulphonyl , trifluoromethanesulphonyl, 2,4,6- triisopropylbenzenesulphonyl , 2,4,6- trimethylbenzenesulphonyl , 2-mesitylenesulphonyl , methanesulphonyl, 4-methoxybenzenesulphonyl, 1- naphthalenesulphonyl , 2-naphthalenesulphonyl , ethane- sulphonyl, 4-fluorobenzenesulphonyl and 1-hexadecane- sulphonyl. Preferably, the sulphonyl group is p- toluenesulphonyl or trifluoromethanesulphonyl. If D is a nitrogen atom and Y is a sulphonyl group, the compound according to the formula (R'_πD-R-Y) is formed in situ by reacting an aminoalcohol compound (R'₂NR-OH) consecutively with a base (such as described above), potassium or sodium and a sulphonyl halide (Sul-X).

The second reaction step can also be carried out in a polar solvent as described for the first step. The temperature at which the reaction is carried out is -60 to 80°C. Reactions with X-R-Sul and with R'_nD-R-Y in which Y is Br or I are usually carried out at a temperature between -20 and 20°C. Reactions with R'_nD-R-Y in which Y is Cl are usually carried out at a higher temperature (10 to 80°C). The upper limit for the temperature at which the reactions are carried out is determined in part by the boiling point of the compound R'_nD-R-Y. After the reaction with a compound of the formula (X-R-Sul) another reaction is carried out with LiDR'_n or HDR'_n in order to replace X by a DR'_n functionality. This reaction is carried out at 20 to 80°C, optionally in the same dispersant as mentioned in the foregoing.

During the synthesis process according to the invention, geminal products may in part be formed. A geminal substitution is a substitution in which the number of substituents increases by 1, but in which the number of substituted carbon atoms does not increase. The amount of geminal products formed is low if the synthesis is carried out starting from a substituted Cp compound containing 1 substituent and increases as the substituted Cp compound contains more substituents. If sterically large substituents are present on the substituted Cp compound, geminal products are not, or are scarcely, formed. Examples of sterically large substituents are secondary or tertiary alkyl substituents. The amount of geminal product formed is also low if the second step of the reaction is carried out under the influence of a Lewis base whose conjugated acid has a dissociation constant for which pK_a is less than or equal to -2.5. The pK_a values are based on D. D. Perrin: Dissociation Constants of Organic Bases in Aqueous Solution, International Union of Pure and Applied Chemistry, Butterworths, London 1965. The values have been determined in aqueous H₂S0₄ solution. Ethers can be mentioned as examples of suitable weak Lewis bases.

If geminal products have formed during the process according to the invention, said products can easily be separated from the nongeminal products by converting the mixture of geminally and nongeminally substituted products into a salt by reaction with potassium, sodium or a base, after which the salt is washed with a dispersant in which the salt of the nongeminal products is insoluble or sparingly soluble. The compounds mentioned above may be used as base. Suitable dispersants are nonpolar dispersants, such as alkanes. Examples of suitable alkanes are: heptane and hexane. Metal complexes as defined in the foregoing and in which at least one cyclopentadiene compound as defined above is present appear to be stereoselective in the polymerization of olefins. The invention therefore also relates to such metal complexes and the use thereof as catalyst component for the polymerization of olefins. These metal complexes may comprise as ligands one or more Cp compounds according to the invention; two of such ligands may be connected by a bridge. The polymerization of α-olefins, for example ethene, propene, butene, hexene, octene and mixtures thereof and mixtures with dienes, can be carried out in the presence of the metal complexes with the Cp compounds according to the invention as ligand. Suitable in particular for this purpose are complexes of transition metals which are not in their highest valency state, in which just one of the cyclopentadienyl compounds according to the invention is present as ligand and in which the metal is cationic during the polymerization. Said polymerizations can be carried out in the manner known for the purpose and the use of the metal complexes as catalyst component does not make any essential adaptation of these processes necessary. The known polymerizations are carried out in suspension, solution, emulsion, gas phase or as bulk polymerization. The cocatalysts usually applied are for example methylaluminoxanes, tris(pentafluorophenyl ) borate, dimethylanilinium tetra(pentafluorophenyl ) borate or mixtures thereof. The polymerizations are carried out at temperatures between -50°C and +350°C, more particularly between 25 and 250°C. The pressures used are generally between atmospheric pressure and

2500 atm. , for bulk polymerizations more particularly between 500 and 2500 atm. , and for the other polymerization processes between 5 and 250 atm. As dispersants and solvents, use may be made of, for example, hydrocarbons, such as pentane, heptane and mixtures thereof. Aromatic, optionally perfluorinated hydrocarbons, are also suitable.

The invention will be elucidated by means of the following examples, without being restricted thereto. For characterization the following analysis methods were used: Gas chromatography was performed on a Hewlett Packard 5890 Series II with an HP Crosslinked Methyl Silicon Gum (25 m x 0.32 mm x 1.05 μm) column. Gas chromatography combined with mass spectro etry ( GC- MS) was performed with a Fisons MD800, equipped with a quadrupole mass detector, autoinjector Fisons AS800 and CPSilδ column (30 m x 0.25 mm x 1 μm, low bleed). NMR was performed with a Bruker ACP200 NMR (^λH = 200 MHz; ¹³C = 50 MHz) or Bruker ARX400 NMR (^XH = 400 MHz; ¹³C = 100 MHz). Metal complexes were characterized using a Kratos MS80 mass spectrometer or a Finnigan Mat 4610 mass spectrometer. Experiment I

Preparation of 2-(N,N-dimethylamino)ethyl tosylate in situ

A solution of n-butyllithium in hexane (1 equivalent) was added at -10°C (dispensing time: 60 minutes) to a solution of 2-dimethylaminoethanol (1 equivalent) in dry THF under dry nitrogen in a three- neck round-bottom flask provided with a magnetic stirrer and a dropping funnel. After all the butyllithium had been added, the mixture was brought to room temperature and stirred for 2 hours. The mixture was then cooled (-10°C), after which paratoluenesulphonyl chloride (1 equivalent) was added. The solution was then stirred for 15 minutes at this temperature before the solution was added to a cyclopentadienyl anion.

Comparable tosylates can be prepared in an analogous way. In a number of the examples below, a tosylate is always coupled to alkylated Cp compounds. During this coupling, geminal coupling also takes place in addition to the required substitution reaction. In nearly all cases it was possible to separate the geminal isomers from the nongeminal isomers by converting the nongeminal isomers into their sparingly soluble potassium salt, followed by washing of said salt with a solvent in which said salt is not soluble or is sparingly soluble.

Example II Preparation of di- and tri(2-pentyl)cyclopentadiene

A do ble-walled reactor having a capacity of 1 1 and provid i with baffles, condenser, top stirrer, thermometer and dropping funnel was filled with 900 g (11.25 mol) of clear 50% NaOH. Then 31 g (77 mmol) of Aliquat 336 and 26.8 g (0.41 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 155 g (1.03 mol) of 2-pentyl bromide were added in one hour. During this process, the mixture was cooled with water. After stirring for 3 hours at room temperature, the reaction mixture was heated to 70°C, after which stirring was carried out again for 2 hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 900 g (11.25 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further two hours at 70°C. It was demonstrated with GC that the mixture was composed of di- and tri(2- pentyl)cyclopentadiene (approximately 1:1) at that instant. The products were distilled at respectively 2 mbar, 79-81°C and 0.5 mbar, 102°C. After distillation, 28 g of di- and 40 g of tri(2-pentyl)cyclopentadiene were obtained. The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^λH-NMR.

b. Preparation of (dimethylaminoethyl)di(2- pentyl )cyclopentadiene A solution of n-butyllithium in hexane (24.0 ml; 1.6 mol/1; 38 mmol) was added dropwise to a cooled (0°C) solution of di-2-pentylcyclopentadiene (7.82 g; 38.0 mmol) in dry tetrahydrofuran (125 ml) in a 250 ml three-neck round-bottom flask provided with magnetic stirrer and dropping funnel. After stirring for 24 hours at room temperature, 2-dimethylaminoethyl tosylate (38.0 mmol) prepared in situ was added. After stirring for 18 hours, the conversion was found to be 92% and water (100 ml) was carefully added dropwise to the reaction mixture, after which the tetrahydrofuran was distilled off. The crude product was extracted with ether, after which the combined organic phase was dried (sodium sulphate) and evaporated down. The residue was purified using a column containing silica gel, resulting in 8.2 g of (dimethylaminoethyl)di-2- pentylcyclopentadiene. c. Synthesis of l-(dimethylaminoethyl ) -2 , 4-di ( 2- pentyl )cyclopentadienyltitanium(III)dichloride and ri- (dimethylaminoethyl ) -2 , -di (2- pentyl )cvclopentadienyl ldimethyltitaniumflll) rc₅H,(2-C₅H,■ )₇(CH_?)_?NMe_?TidII)Me_?l (Catαalvst IIA)

In a Schlenk vessel 1.60 g (5.77 mmol) of (dimethylaminoethyl)di(2-pentyl)cyclopentadiene were dissolved in 40 L of diethyl ether, after which the solution was cooled to -60°C. Then 3.6 mL of n- butyllithium (1.6M in hexane; 5.77 mmol) were added dropwise. The reaction mixture was slowly brought to room temperature, which was followed by another 2 hours' stirring. In a second Schlenk vessel 40 mL of tetrahydrofuran were added to 2,14 g Ti (III)C1₃.3THF

(5.77 mmol). Both Schlenk vessels were cooled to -60°C, after which the organolithium compound was added to the Ti(III)Cl₃ suspension. The reaction mixture was then stirred for 18 hours at room temperature, after which the solvent was evaporated. 50 mL of petroleum ether were added to the residue, which was then boiled down again. 1.60 g of a green solid substance remained, containing l-(dimethylaminoethyl)-2 , 4-di (2- pentyl )cyclopentadienyl-titanium(III)dichloride. In a Schlenk vessel 0.33 g (0.835 mmol) of 1-

(dimethylaminoethyl)-2 , 4-di (2- pentyl )cyclopentadienyltitanium(III)dichloride were dissolved in 40 mL of diethyl ether. The solution was cooled to -60°C, after which 0.90 mL of methyllithium (1.84M in diethyl ether; 1.66 mmol) were added dropwise. The reaction mixture was slowly brought to room temperature, which was followed by another 1 hour's stirring. Then the solvent was evaporated. The residue was extracted with 50 mL of petroleum ether and the filtrate was boiled down. 0.24 g of a black/brown oil remained, containing [l-(dimethylaminoethyl)-2 , 4- di (2-pentyl)cyclopentadienyl]dimethyltitanium(III) . Example III a. Preparation of di (n-butylaminoethyl)tri ( 2- pentyl )cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl )di (2-pentyl)cyclopentadiene, the tosylate of N,N-di-n-butylaminoethanol being prepared in situ. The conversion was 88%. The di-(n- butylaminoethyl)di(2-pentyl)cyclopentadiene was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, followed by distillation under reduced pressure, with a yield of 51%.

b. Synthesis of l-(di-n-butylaminoethyl )-2 , -di ( 2- pentyl )cyclopentadienyltitaniumfIII )dichloride

IC₅H₂f2-C₅H₁₁l₂χCH₂l₂N(n-C₄H₉l₂Ti(III)Cl₂l

In a Schlenk vessel 0.919 g (2.54 mmol) of (di-n-butylaminoethyl)di (2-pentyl )cyclopentadiene were dissolved in 40 mL of diethyl ether, after which the solution was cooled to -60°C. Then 1.6 mL of n- butyllithium (1.6M in hexane? 2.56 mmol) were added dropwise. The reaction mixture was slowly brought to room temperature, which was followed by another 2 hours' stirring. Then this was added to 960 mg (2.59 mmol) of Ti(III)C1₃.3THF in 20 mL of tetrahydrofuran. The reaction mixture was then stirred for 18 hours at room temperature, after which the solvent was evaporated. The residue was washed with 10 mL. 0.95 g of a green solid substance remained, containing l-(di- n-butylaminoethyl )-2, -di(2-pentyl)cyclopentadienyl- titanium(IlI)dichloride.

Example IV a. Preparation of di (n-butylaminoethyl )tri (2- pentyl )cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)di (2-pentyl)cyclopentadiene, the tosylate of N,N-di-n-butylaminoethanol being prepared in situ. The conversion was 88%. The di(n- butylaminoethyl )tri (2-pent l)cyclopentadiene was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, followed by distillation under reduced pressure, with a yield of 51%.

b. Synthesis of l-(di-n-butylaminoethyl ) -2 , 3 , 5-tri(2- pentyl )cvclopentadienyltitanium(III)dichloride rC₅H(2-C_cH,₁ )_?(CH_?)_?N(n-Bu)₇Ti(III)Cl_?1

2.633 g (6.11 mmol) of (di-n- butylaminoethyl )tri (2-pentyl )cyclopentadiene were dissolved in 50 mL of diethyl ether and cooled to - 78°C. Then 3.8 mL of n-butyllithium (1.6 M in hexane;

6.11 mmol) were added. After 18 hours' stirring at room temperature the clear light-yellow solution was boiled down and washed one time with 25 mL of petroleum ether. Then the solvent was evaporated completely and 1.58 g of a yellow oil remained, containing lithium l-(di-n- butylaminoethyl)-2 , 3 , 5-tri (2-pentyl )cyclopentadienyl . Next, the organolithium compound was dissolved in 50 mL of tetrahydrofuran and added to 9.23 g (24.9 mmol) of Ti(III)Cl₃.3THF in 50 mL of tetrahydrofuran. After stirring for 18 hours at room temperature a dark-green solution was obtained. This solution was boiled down completely and 1.52 g of a green oil remained, containing l-(di-n-butylaminoethyl )-2 ,3,5-tri (2- pentyl)cyclopentadienyltitanium(III)dichloride.

Example V a. Preparation of di (2-butyl )cyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, condenser, top stirrer, thermometer and dropping funnel was filled with 600 g of clear 50% NaOH (7.5 mol), after which the contents were cooled to 10°C. Then 30 g of Aliquat 336 (74 mmol) and 48.2 g (0.73 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 200 g (1.46 mol) of 2-butyl bromide were added in half an hour. During this process, the mixture was cooled with water. After stirring for 2 hours at room temperature, the reaction mixture was heated to 60°C, after which stirring was carried out again for 4 hours. It was demonstrated with GC that more than 90% of di(2- butyl)cyclopentadiene was present in the mixture at that instant. The product was distilled at 20 mbar and 80 - 90°C. After distillation, 90.8 g of di(2- butyl)cyclopentadiene were obtained. The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^-N R.

b. Preparation of (dimethylaminoethyl)di(2- butyl)cyclopentadiene

A solution of n-butyllithium in hexane (31.2 ml; 1.6 mol/1; 50 mmol) was added dropwise to a cooled (0°C) solution of di(2-butyl)cyclopentadiene (8.90 g; 50.0 mmol) in dry tetrahydrofuran (150 ml) under a nitrogen atmosphere in a 500 ml three-neck round-bottom flask provided with magnetic stirrer and dropping funnel. After stirring for 24 hours at room temperature, 2-dimethylaminoethyl tosylate (50.0 mmol) prepared in situ was added. After stirring for 18 hours, the conversion was found to be 96% and water (100 ml) was carefully added dropwise to the reaction mixture, after which the tetrahydrofuran was distilled off. The crude product was extracted with ether, after which the combined organic phase was dried (sodium sulphate) and evaporated down. The residue was purified using a silica gel column, resulting in 8.5 g of (dimethylaminoethyl)di(2-butyl)cyclopentadiene. c. Synthesis of l-(dimethylaminoethyl )-2 ,4-di ( 2- butyl )cyclopentadienyltitanium(III)dichloride and r 1- (dimethylaminoethyl ) -2 ,4-di(2- butyl )cyclopentadienyl ldimethyltitanium(III) rC₅H (2-C_J,H_a)₇(CH₇)_?NMe_?Ti(III)Cl_?l and rC₅H₇(2- CiH_j)₃(CH₇) ₇NMe₇Ti (III)Me₇1

In a Schlenk vessel 2.36 g (9.48 mmol) of (dimethylaminoethyl )di (2-butyl)cyclopentadiene were dissolved in 50 mL of diethyl ether, after which the solution was cooled to -60°C. Then 5,9 mL of n- butyllithium (1.6M in hexane; 9.44 mmol) were added dropwise. The reaction mixture was slowly brought to room temperature, which was followed by another 2 hours' stirring. In a second Schlenk vessel 50 mL of tetrahydrofuran were added to 3.15 g of Ti (III)C1₃.3THF (9.44 mmol). Both Schlenk vessels were cooled to -60°C, after which the organolithium compound was added to the Ti(III)Cl₃ suspension. The reaction mixture was then stirred for 18 hours at room temperature, after which the solvent was evaporated. 50 mL of petroleum ether were added to the residue, which was then boiled down again. 2.15 g of a green solid substance remained, containing l-(dimethylaminoethyl)-2 , 4-di (2- butyl )cyclopentadienyl-titanium(III)dichloride. In a Schlenk vessel 0.45 g (1.22 mmol) of 1-

(dimethylaminoethyl)di(2- butyl )cyclopentadienyltitanium(IIIJdichloride was dissolved in 40 mL of diethyl ether. The solution was cooled to -60°C, after which 1.33 mL of methyllithium (1.84M in diethyl ether; 2.44 mmol) were added dropwise. The reaction mixture was slowly brought to room temperature, which was followed by another 1 hour's stirring. Then the solvent was evaporated. The residue was extracted with 50 mL of petroleum ether and the filtrate was boiled down. 0.36 g of a black/brown oil remained, containing [ l-(dimethylaminoethyl)-2 , 4- di ₍2-butyl)cyclopentadienyl] imethyltitanium(III) . Example VI a. Preparation of tri(2-butyl)cyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, condenser, top stirrer, thermometer and dropping funnel was filled with 400 g (5.0 mol) of clear 50% NaOH. Then 9.6 g ( 24 mmol) of Aliquat 336 and 15.2 g (0.23 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 99.8 g (0.73 mol) of 2-butyl bromide were added in half an hour. During this process, the mixture was cooled with water. After stirring for half an hour at room temperature, the reaction mixture was heated to 70°C, after which stirring was carried out again for three hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 400 g (5.0 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further 2 hours at 70°C. It was demonstrated with GC that more than 90% tri(2- butyl)cyclopentadiene was present in the mixture of di, tri- and tetra(2-butyl)cyclopentadiene at that instant. The product was distilled at 1 mbar and 91°C. After distillation, 40.9 g of tri(2-butyl)cyclopentadiene were obtained. The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^XH-NMR.

b. Preparation of (dimethylaminoethyl)tri(2- butyl)cvclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)di(2-butyl)cyclopentadiene. The conversion was 92%. The product was obtained distillatively with a yield of 64%. c. Synthesis of f1-(dimethylaminoethyl)-2,3,5-tri (2- butyl )cvclo^pentadienyltitanium(III)dichloride and π- (dimethylaminoethyl )-2 , 3, 5-tri (2- butyl)cvclopentadienyl ldimethyltitaniumdll) C₁H_g ,(CH₇)₇NMe_?Ti(III)Me-,l

In a 500 mL three-neck flask 200 mL of petroleum ether were added to 6.28 g (20.6 mmol) of potassium l-(dimethylaminoethyl )-2 , 3, 5-tri (2- butyl )cyclopentadienyl . In a second (1 L) three-neck flask, 300 ml of tetrahydrofuran were added to 7.65 g (20.6 mmol) of Ti (III)C1₃.3THF. Both flasks were cooled to -60°C, after which the organopotassium compound was added to the Ti(III)Cl₃ suspension. The reaction mixture containing 1-(dimethylaminoethyl )-2,3 , 5-tri(2- butyl)cyclopentadienyltitanium(III)dichloride was slowly brought to room temperature, which was followed by another 18 hours' stirring. After cooling to -60°C, 22.3 mL of methyllithium (1.827 M in diethyl ether; 40.7 mmol) were added. After 2 hours' stirring at room temperature the solvent was removed and the residue was dried for 18 hours under vacuum. 700 mL of petroleum ether were added to the product and then filtration was effected. The filtrate was boiled down and dried for 2 hours under vacuum. 7.93 g of a brown/black oil remained, containing [ 1-(dimethylaminoethyl)-2 , 3,5- tri (2-butyl)cyclopentadienyl]dimethyltitanium(III) .

Polymerization experiment VII A. The copolvmerization of ethene with propene was carried out as follows:

Under dry nitrogen a 1-litre stainless steel reactor was filled with 400 ml of pentamethyl heptane (PMH) and 30 μmol of triethyl aluminium (TEA) or trioctyl aluminium (TOA) as scavenger. The reactor was pressurized to 0.9 MPa with purified monomers and so conditioned that the propene : ethene ratio in the gas above the PMH was 1 : 1. The reactor contents were brought to the required temperature with stirring.

After conditioning of the reactor the metal complex (5 μmol) to be used as catalyst component and the cocatalyst (30 μmol BF₂₀) were pre-mixed for 1 minute and supplied to the reactor with the aid of a pump. The mixture was pre-mixed in about 25 ml of PMH in a catalyst dispensing vessel and purged with about 75 ml of PMH, all under a dry nitrogen flow. During the polymerization the monomer concentrations were kept constant as much as possible by supplying propene (125 N-litres/h) and ethene (125 N-litres/h) to the reactor. The reaction was followed by monitoring the course of the temperature and the monomer supply.

After 10 minutes' polymerization the monomer supply was stopped and the solution was drained off under pressure and collected. The polymer was dried under vacuum for 16 hours at about 120°C.

B. The homopolymerization of ethene and the copolymerization of ethene with octene were carried out as follows:

600 ml of an alkane mixture (pentamethyl heptane or special boiling point solvent were supplied to a 1.5-litre stainless steel reactor under dry nitrogen as reaction medium. Then the envisaged amount of dry octene (which may also be nil) was introduced into the reactor. Next the reactor was heated to the required temperature with stirring under the required ethene pressure.

25 ml of the alkane mixture as solvent were supplied to a 100-ml catalyst dispensing vessel. In this vessel the required amount of an Al-containing cocatalyst was pre-mixed for 1 minute with the required amount of metal complex such that the Al/(metal in the complex) was equal to 2000. This mixture was then supplied to the reactor and the polymerization started. The polymerization reaction was carried out isothermall . The ethylene pressure was kept constant at the set pressure. Upon completion of the required reaction time the ethene supply was stopped and the reaction mixture was drained off and quenched with methanol.

The reaction mixture with methanol was washed with water and HCl in order to remove the catalyst residues. Then the mixture was neutralized with NaHC0₃. Next, an antioxidant (Irganox 1076, TM) was added to the organic fraction for the purpose of stabilization of the polymer. The polymer was dried under vacuum at 70°C for 24 hours. In both cases the following conditions were varied:

- metal complex

- type and amount of scavenger

- type and amount of cocatalyst - temperature

The actual conditions of each case are stated in Table I.

TABLE I

HAO: methylaluminoxane from Witco

Claims

C L A I M S

1. Substituted cyclopentadiene compound comprising at least one chiral atom, characterized in that the chiral atom is not bonded directly to the

cyclopentadiene.

2. Substituted cyclopentadiene compound comprising at least two chiral atoms.

3. Compound according to Claim 1 or 2 in which at

least one chiral atom is a hetero atom chosen from groups 14-15 of the Periodic System.

4. Substituted cyclopentadiene compound comprising, besides a substituent which contains at least one chiral atom, a group of the form RDR'_n as a further substituent, where R is a bonding group between the cyclopentadiene and the DR ' group, D is a hetero atom chosen from group 15 or 16 of the Periodic System of the Elements, R' is a

substituent and n is the number of R' groups bonded to D.

5. Metal complex in which at least one compound

according to any one of Claims 1-4 is present as a ligand.

6. Application of a metal complex according to Claim 5 as a catalyst component in the polymerization of α-olefins.