WO1997042165A1

WO1997042165A1 - Fluorene substituted with a group comprising a hetero atom

Info

Publication number: WO1997042165A1
Application number: PCT/NL1997/000214
Authority: WO
Inventors: Gerardus Johannes Maria Gruter; Johannes Antonius Maria Van Beek; Marc Herklots
Original assignee: Dsm N.V.
Priority date: 1996-05-03
Filing date: 1997-04-23
Publication date: 1997-11-13
Also published as: AU2409297A; NL1003017C2

Abstract

Substituted fluorene compound which comprises at least one substituent of the form -RDR'n where R is a bonding group between the fluorene 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 application thereof as a ligand in a metal complex. 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

FLUORENE SUBSTITUTED WITH A GROUP COMPRISING

A HETERO ATOM

The invention relates to a substituted fluorene compound which comprises at least one substituent of the form -RDR'_n, where R is a bonding group between the fluorene 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. For the Periodic System of the Elements, 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.

In the following, fluorene will be abbreviated to 'Flu'. The same abbreviation will be used for a fiuorenyl group if it is clear, from the context, whether fluorene itself or its anion is meant.

Metal complexes comprising cyclopentadiene compounds as ligands are generally used as catalyst components for the polymerization of in particular α- olefins. Mostly it is mentioned that cyclopentadiene- based compounds such as fluorene can also be used as ligands. So far, fluorene compounds have only been used in so-called sandwich compounds. These are metal complexes in which two cyclopentadienyl derivatives are bound to the metal, at least one of which is a fluorene compound in this case. It is not known if and if so, in what other form and in what differently structured metal complexes suitable as a catalyst component, fluorene could be a suitable ligand. Surprisingly it has been found now that catalyst components that are very suitable for olefin polymerization can be obtained if the Flu compounds according to the invention are singly used as a ligand on a metal which is not in its highest valency state. Thus a mono-Flu-substituted metal complex is obtained of metals that are not in their highest possible valency state, in which the Flu-comprising ligand has a strongly stabilizing effect without blocking the active sites of the complex, so that the complexes in cationic form offer an excellent catalytic effect.

Corresponding complexes in which the Flu compound has not been substituted as described in the foregoing, appear to be unstable or, if they have been stabilized in another way, to possess poorer catalytic properties than the complexes with substituted Flu compounds according to the invention.

Further it appears that the Flu 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 appear to be suitable as stable and volatile precursors for use in metal chemical vapour deposition. 9-methyldimethylamine fluorene is known from

J. Org. Chem., 1989, 54, 4302-13. 9-fluorenyl-ethoxy- dimethylsilan is known from EP-A-693.497 and in a publication by King et al, (J.A.C.S., 77, 1955, 2217- 2223) some 9-dialkylaminoalkylfluorenes are described. The particular suitability of these and similar compounds as a ligand on a metal which is not in its highest valency state can in no way be derived or suspected from these publications.

By a substituted Flu compound is understood a fluorene substituted with at least one group of the form RDR'_n. In addition, other groups of the form R² as defined hereinafter may also be present on positions on the two 6-rings of the fluorene. The RDR'_n group is preferably present on the 9-position of the fluorene.

The Flu compound can also be a hetero fluorene compound. Here and in the following a hetero fluorene group is understood to be a group that is derived from fluorene, but in which at least one of the carbon atoms thereof has been replaced by a hetero atom, the hetero atom being chosen from group 14, 15 or 16 of the Periodic System of the Elements. If more than one hetero atom is present, the hetero atoms can be identical or different. More preferably, the hetero atom has been chosen from group 15; still more preferably, the hetero atom is nitrogen.

The R² groups can each separately be hydrogen or 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. Two adjacent hydrocarbon radicals may also be connected to each other in a ring system. R² can also be a substituent which, in addition to or instead of carbon and/or hydrogen, comprises one or more hetero atoms from groups 14-17 of the Periodic System of the Elements. Thus a substituent can be a group comprising N, 0, F and/or Si. R² should not be a cyclopentadienyl or a cyclopentadienyl-based group.

In the substituent of the form RDR'_n the R group constitutes the bridge between the Flu and the DR'_n group. The length of the shortest bridge between the Flu and D, in the following referred to as "the main chain of R", is critical in that 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. The R group is at least one atom long. 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:

(-ER³ ₂-)_p

where p = 1-4 and E represents an element from group 14 of the Periodic System. The R³ groups are as defined for R².

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) (SiR³ ₂)~) . The alkyl groups (R³) 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' groups can be identical or different and can be chosen from the same groups as defined for R², with the exception of hydrogen. 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.

When applied as a sole ligand in a metal complex in which the metal is not in its highest valency state, the optionally multiply substituted Flu compounds according to the invention appear to give compounds offering a good stability and a good catalytic effect. The invention therefore also relates to this application. As a matter of fact the substituted Flu compounds also give good results when used singly or multiply as ligands on metals which actually are in their highest valency state. In that case as well, active catalysts are obtained, which in many cases give better results in a specific application than the known Flu-comprising ligands. 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 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 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 term 'olefins' here and in the following 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.

The invention therefore also relates to metal complexes of said composition and their application as catalysts in particular for the polymerization of olefins, both linear and branched and cyclic ones and conjugated or non-conjugated dienes and mixtures thereof.

The group of the form RDR'_n can be substituted on the 9-position of a Flu compound which may already have been substituted on one or more positions of the six-rings. Processes for the substitution of Flu with groups other than RDR'_n groups are known for instance from Bull. Chem. Soc. of Japan, 59, 97-103 (1986) and Liebigs Ann. Chem. 1976, 74-88. The RDR'_n group can be incorporated for instance by means of the following synthesis route, provided that the 9-position of the fluorene has not been substituted.

In a first step of this route a substituted Flu 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 fiuorenyl anion obtained is reacted 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 (X) or a sulphonyl group (Sul). The halogen atom X may be for instance 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 groups 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'_nD-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.

The synthesis of metal complexes with the above-described specific Flu compounds as a ligand can take place according to the processes known per se for this purpose. The use of these Flu compounds does not require any adaptations of said known processes. In such a process the substituted Flu compound is converted into an anion with the aid of for instance a lithium alkyl or a Grignard compound and subsequently the anion is reacted with a metal halide. The Li-Flu compound or the corresponding Flu compound obtained with the aid of the Grignard compound can also be converted into a Si- or Sn-Flu compound, which is subsequently reacted with the metal halide.

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 fiuorenyl 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 fiuorenyl 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) borane, 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.

For characterization of the products obtained the following analysis methods were used.

The invention will be elucidated by means of the following examples, without being restricted thereto. Gas chromatography (GC) 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 l μm, low bleed). NMR was performed with a Bruker ACP200 (-H = 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-fN,N-dimethylamino)ethyl tosylate in situ

A solution of n-butyl lithium 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 butyl lithium 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 it was added to a fiuorenyl anion. Comparable tosylates can be prepared in an analogous way.

Example II a: Preparation of (dimethylaminoethyl)fluorene 30 mL of a 1.6M solution of n-butyl lithium in hexane was added dropwise to a cooled (0°C) solution of fluorene (8 g; 48.1 mmol) in dry tetrahydrofuran (125 ml) in a 250 ml three-neck round-bottom flask provided with a magnetic stirrer and a dropping funnel. After stirring for 24 hours at room temperature, a solution in THF/hexane of 2-dimethylaminoethyl tosylate (48 mmol) prepared in situ was added. After stirring for 18 hours, the conversion was found to be 90% 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 (on sodium sulphate) and evaporated down. The residue ^• was purified using a column containing silica gel, resulting in 9.1 g (80%) of

(dimethylaminoethyl)fluorene.

b. Synthesis of (dimethylaminoethyl)fiuorenyl titanium dichloride In a 200-ml Schlenk flask 6.2 mL of a 1.6M solution of butyl lithium in hexane was added to (dimethylaminoethyl)fluorene (2.37 g, 10 mmol) dissolved in 30 mL of tetrahydrofuran at 0°C (ice bath). After 15 minutes' stirring this mixture was cooled further to -78°C and a slurry of Ti(III)C1₃.3THF (3.71 g, 10 mmol) in 30 ml of THF, also cooled to -78°C, was added. The cooling bath was removed and the dark-green/brown solution obtained was stirred for 80 hours at room temperature. After boiling down, 45 mL of petroleum ether (40-60) was added. Complete boiling down was repeated and a greenish/brownish powder (4 g) was obtained, containing (dimethylaminoethyl)fluorenyl titanium dichloride.

Comparative Experiment A Preparation of (fiuorenyl)titanium dichloride

The preparation was carried out as synthesis as in example I, but now with 1.71 g of fluorene (10.2 mmol), 6.4 mL of a 1.6M solution of butyl lithium in hexane and 3.78 g of TiCl₃.3THF (10.2 mmol). 2.95 g of material was obtained in which the envisaged material could not be characterized positively.

Examples III-IV and Comparative Experiments B and C Ethene/octene copolymerization The copolymerization reactions 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 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.

This mixture was then supplied to the reactor and the polymerization started. The polymerization reaction was carried out isothermally. 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.

Capable of variation are:

- metal complex

- temperature

The catalyst obtained in example II was used at two different temperatures in polymerization experiments III and IV. For the purpose of comparison the catalyst obtained in example A was used at the same two temperatures in polymerization experiments B and C. The actual conditions are stated in Table I.

Table I

CA)

1

MAO: methyialuminoxane from Witco

10

Claims

C L A I M S

1. Substituted fluorene compound which comprises at least one substituent of the form -RDR'_n, where R is a bonding group between the fluorene 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, with the exception of 9- methyldimethylamine fluorene, 9-fluorenyl-ethoxy- dimethylsilan and fluorene compounds substituted at the 9-position with a group of the form -RNR'₂, in which R = ethylene and R' = methyl or ethyl, in which R = propylene and R' = methyl, in which R = ethylene and R' = (CH₂CH₂)₂0 or in which R = 2- methylethylene and R' = methyl.

2. Compound according to Claim 1, wherein the RDR'_n group has been substituted on the 9-position.

3. Compound according to Claim 1 or 2, wherein the R- group is structured as

(-ER³ ₂-)_p

wherein p = 1-4, E represents an element from group 14 of the Periodic System and wherein the R₃ groups are each separately H or a hydrocarbon radical.

4. Compound according to any one of Claims 1-3, wherein D has been chosen from the group comprising N, 0, P and S.

5. Compound according to any one of Claims 1-3, wherein D is nitrogen.

6. Metal complex in which one fluorene compound according to any one of Claims 1-5 is present as a ligand.

7. Metal complex in which the metal present is not in its highest valency state and which comprises a compound according to any one of Claims 1-5 as a ligand.

8. Metal complex according to Claim 6 or 7, wherein the metal is a transition metal from group 4, 5 or 6 of the Periodic System or a lanthanide.

9. Metal complex according to Claim 8, wherein the transition metal has been chosen from the group comprising Ti, Hf, Zr and V.

10. Use of a metal complex according to any one of Claims 6-9 as a catalyst component.

11. Use of a catalyst component according to Claim 10 for the polymerization of olefins.