WO1997042160A1

WO1997042160A1 - Cyclopentadiene compound wherein two or three hetero atoms are present in the substituents

Info

Publication number: WO1997042160A1
Application number: PCT/NL1997/000213
Authority: WO
Inventors: Gerardus Johannes Maria Gruter; Gerardus Henricus Josephus Van Doremaele; Johannes Antonius Maria Van Beek; Matthijs Van Kessel
Original assignee: Dsm N.V.
Priority date: 1996-05-03
Filing date: 1997-04-23
Publication date: 1997-11-13
Also published as: NL1003011C2; AU2409197A

Abstract

Substitued cyclopentadiene compound wherein two or three hetero atoms chosen from group 15 or 16 of the Periodic System are present in the substituents, wherein preferably at least one substituent is of the form -RDR'n, wherein R is a bonding group between the cyclopentadiene compound 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. Metal complexes in which at least one of these cyclopentadiene compounds is present as a ligand are useful as catalysts for the polymerisation of alpha-olefins.

Description

CYCLOPENTADIENECOMPOUNDWHEREINTWOORTHREEHETEROATOMSAREPRESENT INTHESUBSTITUENTS

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 the great majority of cases, either unsubstituted cyclopentadiene or cyclopentadiene substituted with one to five methyl groups is used. Besides transition metals, lanthanides are also used as metals in these complexes.

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.

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.

A drawback of the known substituted Cp compounds is that when used as a ligand on a lanthanide, they form a complex which exhibits only moderate activity as a catalyst component. The object of the invention is to provide substituted Cp compounds which, when used as a ligand in a lanthanide complex, give catalyst components having a better catalytic activity than the known substituted Cp compounds, in particular for the polymerization of olefins. The term olefins here and hereinafter refers to α-olefins, diolefins and other ethylenically unsaturated monomers. Where the term 'polymerization of olefins' is used, this refers both to the polymerization of a single type of olefinic monomer and to the copolymerization of two or more olefins.

This object is achieved according to the invention in that two or three hetero atoms chosen from group 15 or 16 of the Periodic System are present in the substituents.

The presence of at least two hetero atoms in the substituents appears to result in an enhanced activity of lanthanide complexes of which they form part and which are used as catalyst components.

Corresponding lanthanide 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 polymerization of α-olefins.

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.

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 cations. Moreover, the metal complexes containing the Cp compounds according to the invention appear to be suitable as stable and volatile precursors for use in metal chemical vapour deposition.

Geminally substituted Cp compounds are not suitable for use as a ligand and are not considered to be within the scope of the invention.

In a publication of Kresze et al., Chemische Berichte, part 666, 1963, p. 45-53 bis-(β-methoxy-ethyl) Cp is disclosed. The man skilled in the art would not be able to deduce that the Cp compounds according to the invention have the specific advantages as described above from this publication.

The two or three hetero atoms can be identical or different. Further, they can be present together in one and the same Cp substituent, but the two or three hetero atoms can also be present in separate Cp substituents. The Cp substituent in which one or more hetero atoms are present preferably is of the form -RDR'_n, 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 or an aryl group, R' is a substituent and n is the number of R' groups bonded to D.

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 therefore has at least the length of one atom. The R' groups The R' groups can each separately be a hydrocarbon radical with 1-20 carbon atoms (such as alkyl, aryl, aralkyl). 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:

⁽-ERV^),

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, tetraalkyl 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.

The DR'_n group comprises a hetero atom D chosen from group 15 or 16 of the Periodic System of 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.

A compound of the form RDR'_n can be substituted on an unsubstituted Cp, but also on a Cp already substituted on one or more places with another group. Suitable other groups are for instance alkyl groups, both linear and branched ones, alkylene 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, for example O, 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, benzyl, phenyl, paratolyl. A substituted Cp compound can be substituted with a group in the form of -RDR'_n, for example in accordance with the following synthesis route. During a first step of this route a substituted Cp compound is deprotonated by reaction with a base, sodium or potassium.

Possible bases to be used are, for example, organolithium compounds (R³Li) or organomagnesium compounds (R³MgX), where R³ is an alkyl, aryl or aralkyl group, and X is a halide, for example n-butyllithium or i-propylmagnesium chloride. Potassium hydride, sodium hydride, inorganic bases, for example NaOH and KOH, and alcoholates of Li, K and Na can likewise be used as a base. Mixtures of the abovementioned compounds can also be used. This reaction can be carried out in a polar dispersing agent, for example an ether. Examples of suitable ethers are tetrahydrofuran (THF) or dibutyl ether. Nonpolar solvents such as, for example, toluene, can likewise be employed.

Subsequently, during a second step of the synthesis route, the cyclopentadienyl anion formed reacts with a compound according to the formula

(R'_nD-R-Y) or (X-R-Sul), in which D, R, R' and n are as defined hereinabove. Y is a halogen atom (X) or a sulphonyl group (Sul). Halogen atoms X to be mentioned are chlorine, bromine and iodine. Preferably, the halogen atom X is a chlorine atom or a bromine atom.

The sulphonyl group takes the form -0S0₂R⁶, in which R⁶ is a hydrocarbon radical containing 1-20 carbon atoms, for example alkyl, aryl, aralkyl. Examples of such hydrocarbon radicals are butane, pentane, hexane, benzene, naphthalene. Instead of, or in addition to, carbon and/or hydrogen, R⁶ may also contain one or more hetero atoms from groups 14-17 of the Periodic System of the Elements, such as N, 0, Si or F. Examples of sulphonyl groups are: phenylmethanesulphonyl , benzenesulphonyl , 1-butanesulphonyl , 2,5- dichlorobenzenesulphonyl , 5-dimethylamino-l- naphthalenesulphonyl, pentafluorobenzenesulphonyl , p- toluenesulphonyl , trichloromethanesulphonyl , trifluoromethanesulphonyl , 2,4,6- triisopropylbenzenesulphonyl, 2,4,6-trimethylbenzene- sulphonyl, 2-mesitylenesulphonyl, methanesulphonyl , 4- methoxybenzenesulphonyl, 1-naphthalenesulphonyl , 2- naphthalenesulphonyl , ethanesulphonyl , 4- fluorobenzenesulphonyl and 1-hexadecanesulphonyl. 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'_nD-R-Y) is formed in situ by reaction of an aminoalcohol compound (R'₂NR-OH) with a base (such as defined hereinabove), potassium or sodium, followed by a reaction with a sulphonyl halide (Sul-X). The second reaction step can likewise be carried out in a polar dispersing agent such as described for the first step. The temperature at which the reactions are carried out is between -60 and 80°C. Reactions with X-R-Sul and with R'_nD-R-Y in which Y is Br or I, are as a rule carried out at a temperature between -20 and 20°C. Reactions with R'_nD-R-Y in which Y is Cl, are as a rule 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, inter alia, by the boiling point of the compound R'_nD-R-Y and that of the solvent used.

After the reaction with a compound according to the formula (X-R-Sul) a further reaction is carried out with LiDR'_n or HDR'_n to replace X by a DR'_n functionality. To this end a reaction is carried out, possibly in the same dispersing agent as mentioned above, at 20 to 80°C.

In the synthesis process according to the invention it is possible for geminal products to be formed in part. 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 having 1 substituent and increases as the substituted Cp compound contains more substituents. In the presence of sterically large substituents in the substituted Cp compound no or virtually no geminal products are 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 with a pK_a of 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 may be mentioned as an example of suitable weak Lewis bases. If geminal products have been formed during the process according to the invention, these products can be separated in a simple manner from the non- geminal products by converting the mixture of geminally and non-geminally substituted products into a salt, by reaction with potassium, sodium or a base, the salt then being washed with a dispersing agent in which the salt of the non-geminal products is insoluble or sparingly soluble. Bases which can be used include the compounds as mentioned above. Suitable dispersing agents are nonpolar dispersing agents such as alkanes. Examples of suitable alkanes are heptane and hexane.

As already stated in the foregoing, the two hetero atoms can be present within one and the same -RDR'_n group, in which case at least one R' is an RDR' group. Further, it is possible for the two hetero atoms te be present each separately in a group of the form -RDR'_n; these elements and groups can then be chosen independently of each other within the limits indicated in the foregoing for R, D and R'.

Besides the substituents comprising one or two hetero atoms, which are required for the compound according to the invention, other groups may have been substituted on the other positions of the Cp. Cp compounds substituted with other groups can, for instance, be prepared by reacting a halide of the substituting compound in a mixture of Cp compound and an aqueous solution of a base in the presence of a phase transfer catalyst. Preferably, a virtually equivalent quantity of the halogenated substituting compound 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 substituting compounds it is possible to obtain trisubstituted 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 achieve tetra- and often even pentasubstitution.

Substituents that can be applied with the present process are the other substituents mentioned in the foregoing. The substituents are preferably applied in the process in the form of their halides.

By means of this process it is also possible, without intermediate isolation or purification, to obtain Cp compounds which are substituted with 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 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, preferably 6-30 mol per mole of Cp compound. It has appeared that a substantial reduction of the reaction time can be achieved if the solution of the base is refreshed during the reaction, for instance by first mixing the solution of the base with the other components of the reaction mixture and after some time isolating the aqueous phase and replacing it by a fresh portion of solution of the base.

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 suitable, after which the temperature of the reaction mixture can rise due to the heat released in the reaction.

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 from 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 benzyltrimethylammonium hydroxide (Triton B), tetra-n- butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium iodide, tetra-n-butylammonium hydrogen sulphate or tetra-n-butylammonium hydroxide and cetyltrimethylammonium 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, ethyltriphenylphosphonium bromide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium iodide and tetrabutylphosphonium 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-1,10-diazabicyclo[8.8.5Jtricosane (Kryptofix 221), 4,7,13,18-tetraoxa-l,10- diazabicyclo[8.5.5Jeicosane (Kryptofix 211) and 4,7,13,16,21,24-hexaoxa-l,10-diazabicyclo[8.8.8]-hexa- cosane ("[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 polystyrene or another polymer. The phase transfer catalyst is used in an amount of 0.01 - 2 equivalents, preferably 0.05 - 1 equivalent, 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.

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 then recovered from the organic phase by fractional distillation.

By means of the present process, Cp compounds di-, tri- and tetrasubstituted with the desired other groups can be obtained, on which subsequently the hetero-atom-containing group or groups can be substituted, in particular the group or groups of the form -RDR'_n as described in the foregoing.

Lanthanide complexes comprising at least one cyclopentadiene compound as defined in the foregoing, appear to possess improved stability and activity in comparison with similar complexes comprising other Cp compounds as ligands. The invention therefore also relates to such lanthanide complexes and their use as a catalyst component in the polymerization of olefins. In the lanthanide complexes one or more Cp compounds according to the invention can be present as ligands? two of such ligands can be connected by a bridge. Further, corresponding complexes of other metals comprising Cp compounds according to the invention as ligands also appear to be suitable as catalyst components. Further 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. 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 copolymerizations with polar comonomers, hydrogenations and carbonylations. 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, including lanthanide complexes, with the above-described specific Cp compounds as a ligand can 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.

The polymerization of α-olefins, for example ethene, propene, butene, hexene, octene and mixtures thereof and combinations with dienes, can be carried out in the presence of the metal complexes with the cyclopentadienyl compounds according to the invention as a 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 a 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 cocatalyst usually applied is an organometal compound, the metal being chosen from Groups 1, 2, 12 or 13 of the Periodic System of the Elements. To be mentioned are for instance trialkylaluminium, alkylaluminium halides, alkylaluminooxanes (such as 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 250 MPa, for bulk polymerizations more particularly between 50 and 250 MPa, and for the other polymerization processes between 0.5 and 25 MPa. 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 monomer applied in the polymerization can also be used as dispersant or solvent.

The invention will be elucidated by means of the following examples, without being restricted thereto. For characterization of the products obtained the following analysis methods are 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 spectrometry (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 (^XH = 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.

Example I a. Preparation of bis(dimethylaminoethyl)triisopropyl- cvclopentadiene

In a dry 500 ml three-necked flask with a magnetic stirrer, a solution of 62.5 mL of n- butyllithium (1.6M in n-hexane; 100 mmol) was added under a dry nitrogen atmosphere to a solution of 19.2 g (100 mmol) of triisopropylcyclopentadiene in 250 mL of THF at -60°C. After warming to room temperature (in approximately 1 hour) stirring continued for a further 2 hours. After cooling to -60°C, a solution of

(dimethylaminoethyl) tosylate (105 mmol) prepared in situ was added over a period of 5 minutes. The reaction mixture was warmed to room temperature, followed by overnight stirring. After addition of water, the product was extracted with petroleum ether (40 - 60°C). The combined organic layer was dried (Na₂S0₄) and evaporated under reduced pressure. The conversion was greater than 95%. Part of the product thus obtained (10.1 g; 38.2 mmol) was again alkylated under the same circumstances with (dimethylaminoethyl) tosylate (39.0 mmol) . The bis(2- methylaminoethyl)triisopropylcyclopentadiene was obtained with a yield of 35% via column chromatography.

b. Synthesis of r1,3-bis(dimethylaminoethyl)-2,4,5- tri(2-propyl)cvclopentadienyltitanium(III)dichloride and f1,3-bis(dimethylaminoethyl ) -2 ,4,5-tri(2- propyl)cyclopentadienyl1dimethyltitanium(III) rC_;(2-C,H₇)_?( (CH₇)_?NMe_;)₇Ti(III)Cl_?1 and rC₅(2- C,H-,K( (CH_?)₇NMe_?),Ti(III)Me₇1

In a 500 mL three-neck flask 200 mL of petroleum ether were added to 3.38 g (10.1 mmol) of potassium 1,3-bis(dimethylaminoethyl)-2,4,5-tri(2- propyl)cyclopentadienyl. In a second (1 L) three-neck flask, 300 ml of tetrahydrofuran were added to 3.75 g (10.1 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 l-(dimethylaminoethyl)-2,3,5-tri(2- propyl)cyclopentadienyltitanium(III)dichloride was slowly brought to room temperature, which was followed by another 18 hours' stirring. After cooling to -60°C,

11.0 mL of methyllithium (1.827 M in diethyl ether;

20.1 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. 3.62 g of a brown/black oil remained, containing [1,3-bis(dimethylaminoethyl)- 2,4,5-tri(2-propyl)cyclopentadienyl]- dimethyltitanium(III).

c. Synthesis of 1,3-bis(2-dimethylaminoethyl)-2 ,4,5- tri(2-propyl)cvclopentadienylsamariumlllchloride C_?( (CH_?)_?N(CH₃)₃) (2-C,H₇)_?SmCL_?

0.79 g of samariumtrichloride.2,5THF (1.81 mmol) and 0.70 g of 1,3-bis(2-dimethylaminoethyl)- 2,4,5-tri(2-propyl)-cyclopentadienylpotassium (1.79 mmol) were introduced into a Schlenk vessel. This was cooled to -78°C. In another Schlenk vessel, 50 ml of THF was cooled to -78°C. Via a cannula the THF was transferred to the Schlenk vessel with the two reagents, followed by two hours' stirring. Then the mixture was allowed to reach room temperature and it was stirred for two days. The yellow solution was then boiled down and after that 10 ml of ether was added. The precipitate was filtered off and the filtrate was stored at -80°C. Small crystals of l,3-bis(2- dimethylaminoethyl)-2,4,5-tri(2- propyl)cyclopentadienylsamariumlllchloride formed in the filtrate. The liquid was separated from the crystals and the crystals were dried. The mass of the crystals obtained amounted to 0.38 g.

Example II a. Preparation of (N,N' ,N' -trimethyl-3,6-diazaheptyl)- tetramethylcyclopentadiene From 2-lithium-2-butene and

EtOC(0)CH₂CH₂N(Me)CH₂CH₂NMe₂, the compound specified in the opening lines was prepared by the method described in DE-A-4303647, with a yield of 25% based on the amount of ester used as a starting material.

b. Synthesis of fl-(N,N^* ,N' -trimethyl-3,6-diazaheptyl)- 2,3,4, 5-tetramethylcvclopentadienylIdichlorotitanium

(III) [C₅Me₄{(CH₂)₂N(CH₃)(CH₂)₂N(CH₃)₂Ti(III)Cl₂] In a Schlenk vessel, 0.21 g (0.838 mmol) of

(N,N' ,N' -trimethyl-3,6-diazaheptyl)tetramethylcyclo- pentadiene was dissolved in 15 mL of tetrahydrofuran and the solution was then cooled to -60°C. Then 0.52 mL of n-butyllithium (1.6 M in hexane? 0.832 mmol) were added dropwise. After 2.5 hours cooling was stopped, followed by 30 minutes' stirring at room temperature. In a second Schlenk vessel 15 mL of tetrahydrofuran were added to 0.31 g (0.836 mmol) of Ti(III)C1₃' 3THF. Both Schlenk vessels were cooled to -60°C and the organolithium compound was then added to the Ti(III)Cl₃ suspension. After 2 hours cooling was stopped, followed by a further 2 hours' stirring at room temperature. Then the solvent was evaporated. To the residue containing [1-(N,N' ,N' -trimethyl-3,6-diazaheptyl)- 2,3,4,5-tetramethylcyclopentadienyl]titanium(III) dichloride, 40 ml of petroleum ether were added which were subsequently evaporated again. The synthesized catalyst was not worked up further.

Example III a. Preparation of l-(N-methvI-N-(dioxolylmethyl)ethyl)- 2,3,4,5-tetramethylcvclopentadienyltitanium(III)- dichloride [C₅Me₄(CH₂)₂N(Me) (CH₂C₃H_s0₂) ) (Ti(III)Cl₂]

To 0.36 g (1.33 mmol) of lithium l-(N-methyl- N-(dioxolylmethyl)ethyl)-2,3,4,5-tetramethylcyclo- pentadienyl, 40 mL of petroleum ether were added in a Schlenk vessel. To 0.50 g of Ti(III)C1₃.3THF (1.35 mmol), 30 mL of tetrahydrofuran were added in a second Schlenk vessel. Both Schlenk vessels were cooled to -60°C, and the organolithium compound was then added to the Ti(III)Cl₃ suspension. The reaction mixture was stirred at room temperature for 18 hours and the solvent was then evaporated. 50 mL of petroleum ether were added to the residue, followed by evaporation once more. The residue was a green solid, containing 1-((N- methyl-N-(dioxolylmethyl)ethyl)-2,3,4,5- tetramethylcyclopentadienyltitanium(III) dichloride. Polymerization examples IV-V

A. The copolymerization of ethene with propene was carried out in the following manner.

A stainless steel reactor of 1 litre was charged, under dry N₂, with 400 mL of pentamethylheptane (PMH) and 30 μmol of triethylaluminium (TEA) or trioctylaluminium (TOA) as a scavenger. The reactor was pressurized to 0.9 MPa with purified monomers and conditioned in such a way that the ratio propene:ethene in the gas above the PMH was 1:1. The reactor contents were brought to the desired temperature while being stirred.

After conditioning of the reactor, the metal complex (5 μmol) to be used as the catalyst component and the cocatalyst (30 μmol of BF₂₀) were premixed over a period of 1 minute and fed to the reactor by means of a pump. The mixture was premixed in about 25 mL of PMH in a catalyst proportioning vessel and after-rinsing took place with about 75 mL of PMH, always under dry N₂ flow.

During the polymerization the monomer concentrations were kept as constant as possible by supplying the reactor with propene (125 litres [s.t.p. ]/hour) and ethene (125 litres [s.t.p. ]/hour) . The reaction was monitored on the basis of the temperature trend and the progress of the monomer infeed.

After 10 minutes' polymerization the monomer feed was stopped and the solution was drawn off under pressure and collected. The polymer was dried in vacuo for 16 hours at approximately 120°C.

B. The homopolymerization of ethene and the copolymerization of ethene with octene were carried out in the following manner.

600 mL of an alkane mixture (pentamethylheptane or special boiling point solvent) were introduced as the reaction medium, under dry N₂, into a stainless steel reactor having a volume of 1.5 litres. Then the desired amount of dry octene was introduced into the reactor (this amount can therefore also be zero). The reactor was then, with stirring, heated to the desired temperature under a desired ethene pressure.

Into a catalyst proportioning vessel having a volume of 100 mL, 25 mL of the alkane mixture were metered in as a solvent. Herein the desired amount of an Al-containing cocatalyst was premixed over a period of 1 minute, with the desired quantity of metal complex, in such a way that the ratio Al/(metal in the complex) in the reaction mixture is equal to 2000. This mixture was then metered into the reactor, whereupon the polymerization started. The polymerization reaction thus started was carried out isothermally. The ethylene pressure was kept constant at the set pressure. After the desired reaction time the ethene supply was stopped and the reaction mixture was drawn off and quenched with methanol.

The reaction mixture containing methanol was washed with water and HCl, in order to remove residues of catalyst. Then the mixture was neutralized with NaHC0₃, after which the organic fraction was admixed with an antioxidant (Irganox 1076, registered trademark) in order to stabilize the polymer. The polymer was dried in vacuo for 24 hours at 70°C.

In both cases the following conditions were varied: metal complex quantity of cocatalyst temperature

The actual conditions are stated in Table I. Table X

o

MAO : methylaluminoxane, from Witco

Claims

C L A I M S

1. Substituted cyclopentadiene compound characterized in that two or three hetero atoms chosen from group 15 or 16 of the Periodic System are present in the substituents, with the exception of bis(β- methoxyethyl)cyclopentadiene.

2. Cyclopentadiene compound according to Claim 1, wherein at least one substituent is of the form - RDR'_n, wherein R is a bonding group between the cyclopentadiene compound 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 and wherein R' is a group of the form

RDR'n-

3. Cyclopentadiene compound according to Claim 1, wherein at least two substituents are of the form -RDR'_n, wherein R is a bonding group between the cyclopentadiene compound 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.

4. Transition metal complex comprising a metal from

Group 4-10 of the Periodic System and at least one substituted cyclopentadiene compound according to any one of claims 1-3.

5. Lanthanide complex wherein at least one substituted cyclopentadiene compound according to any one of Claims 1-3 is present as a ligand.

6. Use of the transition metal complex according to claim 4 or the lanthanide complex according to Claim 5 as a catalyst component for the polymerization of α-olefins.