WO1997042163A1

WO1997042163A1 - Substituted pentadiene compound

Info

Publication number: WO1997042163A1
Application number: PCT/NL1997/000237
Authority: WO
Inventors: Gerardus Johannes Maria Gruter; Gerardus Henricus Josephus Van Doremaele; Henricus Johannes Arts
Original assignee: Dsm N.V.
Priority date: 1996-05-03
Filing date: 1997-04-29
Publication date: 1997-11-13
Also published as: AU2411397A; NL1003016C2

Abstract

Substituted pentadiene compound according to formula (I) or (II), where R1-2 are substituents and at least one R2 substituent has the form RDR'¿n?, where D is a hetero atom from group 15 or 16 of the Periodic System of the Elements, R' is a substituent on the hetero atom and R is a linking group. The invention also relates to a process for the synthesis of a substituted pentadiene compound. 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

SUBSTITUTED PENTADIENE COMPOUND

The invention relates to a substituted pentadiene compound (pd compound) according to the formula

where: R¹"² are substituents and at least one R² substituent has the form RDR'_n, where

D is a hetero atom from group 15 or 16 of the Periodic System of the Elements,

R' is a substituent on the hetero atom, R is a linking group.

Hereinafter, pentadiene will be abbreviated as 'pd'. The same abbreviation will be used for a pentadienyl group if it is clear, from the context, whether pentadiene itself or its anion is meant. Unsubstituted pentadiene compounds are known.

These compounds are described by, among others, Ernst (Chem. Rev. 1988, 88, 1255-1291). These compounds can be used as ligand in a metallocene catalyst.

Surprisingly, it has been found that excellent catalysts can be obtained if the pd compounds according to the invention are used as ligand in a transition metal complex.

The pd compounds according to the invention prove to be able to stabilize highly reactive intermediates such as organometal hydrides, organometal boron hydrides, organometal alkyls and organometal cations. If, for example, a mono-pd-substituted metal complex is obtained from metals in a lower valency state than the highest possible, in which the pd- containing ligand is mono-anionic, then it has a strongly stabilizing effect without blocking the active sites of the complex, so that the complexes have an excellent catalytic activity. From said publication it is impossible for one skilled in the art to deduce that the compounds according to the invention have such a specific activity. Similar complexes, in which the pd compound is not substituted in the indicated manner, prove to be unstable or, if they are stabilized in another way, have poorer catalytic properties than the complexes with substituted pd compounds according to the invention.

Organometal complexes of the pd compounds according to the invention further prove to be suitable as stable and volatile precursors for use in Metal Chemical Vapour Deposition.

A substituted pd compound is understood to be a pentadiene substituted with at least a group having the form RDR'_n. The R¹ groups may be the same as the R² groups to be defined below. The R¹ groups may also be joined, so that a ring is formed. Preferably, the R¹ groups are joined to form a dimethylmethylene group.

The R¹ groups may each separately be hydrogen or a hydrocarbon radical containing 1 - 20 carbon atoms (such as alkyl, aryl, arylalkyl and the like). Examples of such hydrocarbon radicals are methyl, ethyl, propyl, butyl, hexyl, decyl, phenyl, benzyl and p-tolyl. Two adjacent R² hydrocarbon radicals may also be joined in a ring system. This may even occur twice, so that, when two R¹ groups also form a ring, the pd compound eventually contains 3 rings. Such a group, too, may contain one or more R² groups as substituents. R² may also be a substituent which contains one or more hetero atoms from groups 14 - 16 of the Periodic System of the Elements in addition to or instead of carbon and/or hydrogen. Thus, a substituent may be a group containing N, 0 and/or Si. One R² may also be a cyciopentadienyl group or pd group.

The R group forms the link between the pd and the DR'_n group. The length of the shortest link between the pd and D, hereinafter referred to as the main chain of R, is critical to the extent that it determines the accessibility of the metal in the metal complex for the DR'_n group in order thus to achieve the desired intramolecular coordination. If the R group (or bridge) is too short, ring tension may cause the donor to be unable to coordinate well. The R group may be a hydrocarbon group containing 1 - 20 carbon atoms (such as alkylidene, arylidene, arylalkylidene and the like). Examples of such groups are methylene, ethylene, propylene, butylene, phenylene, optionally having a substituted side chain. Preferably, the R group has the following structure:

(-ER4₂-).

where p = 1-4 and E is an element from group 14 of the Periodic System. The R⁴ groups are as defined for R².

The main chain of the R group may thus contain silicon or germanium besides carbon. Examples of such R groups are: dialkylsilylene, dialkylgermylene, tetra-alkyldisilylene or tetraalkylsilaethylene (-SiR'₂CR'₂-) . The alkyl groups in such a group preferably have 1-4 C atoms and are, more preferably, 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 substituent(s) R^f bound to D. The number of R' groups (n) is coupled to the nature of the hetero atom D, in such a fashion 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 preferably, the hetero atom is nitrogen (N). The R' groups may be the same or different and may be chosen from the same groups as defined for R², with the exception of hydrogen. The R' group is 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 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. The DR'_n group may also be an aryl group, for example phenyl, tolyl, xylyl, mesitylyl, cumyl, tetramethylphenyl, pentamethylphenyl. When a pd substituted with an aryl group as described above is used as ligand on a metal, the coordination of this group on the metal may vary from h.¹ tot ή⁶.

If applied as sole pd-containing ligand in a metal complex in which the metal is not in the highest valency state, the substituted pd compounds according to the invention are found to yield compounds having a good stability and a good catalytic activity. The invention therefore also relates to this application. These compounds, for that matter, also give good results when used as ligands on metals which 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 pd-containing ligands.

Metal complexes which are catalytically active if one of their ligands is a compound according to the invention are the metals from groups 4-12 of the Periodic System and rare earths. 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, Co, Pd and Cr.

The invention therefore also relates to the metal complexes thus composed and their application as catalysts, in particular for the polymerization of olefins, of linear as well as branched and cyclic olefins and optionally conjugated dienes and mixtures thereof.

In this context, complexes of metals from groups 4 and 5 of the Periodic System of the Elements are preferably used as a catalyst component for polymerizing olefins; complexes of metals from groups 6 and 7 of the Periodic System of the Elements in addition also for metathesis and ring-opening metathesis polymerizations, and complexes of metals from groups 8-10 of the Periodic System of the Elements for olefin copolymerizations with polar comonomers, hydrogenations and carbonylations.

The seguence in which the substituents are attached to the pd is free.

At one of the free sites of the pd compound, which is already substituted at one or more positions, a group of the form RDR'_n can be attached, for example via the following synthesis route.

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

Depending on the acid strength of the proton to be abstracted, as base use can be made for example of organolithium compounds (R^sLi) or organomagnesium compounds (R^sMgX), where R⁵ is an alkyl, aryl, or aralkyl group and X is a halide, for example n- butyllithium or i-propylmagnesium chloride. Potassium hydride, sodium hydride, tertiary amines (such as pyridine and triethylamine), 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. Preferably, strong bases are used, such as the mixture of n-butyllithium and potassium-t-butoxide.

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 also be used.

Next, in a second step of the synthesis route the pentadienyl anion obtained reacts with a compound of the formula (DR'_n-R-Y) or (X-R-Sul), where D, R, R' and n are as defined in the foregoing and Y is a halogen atom (X) or a sulphonyl group (Sul).

Halogen atom X may be, for example, chlorine, bromine and iodine. The halogen atom X is preferably a chlorine or bromine atom. The sulphonyl group has the form -OS0₂R⁶, where R⁶ is a hydrocarbon radical containing 1-20 carbon atoms (such as alkyl, aryl, aralkyl, etc.). 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 or F, in addition to or instead of carbon and/or hydrogen. Examples of sulphonyl groups are: phenylmethanesulphonyl, benzenesulphonyl, 1-butane- sulphonyl, 2,5-dichlorobenzenesulphonyl,

5-dimethylamino-l-naphthalenesulphonyl, pentafluoro- benzenesulphonyl, p-toluenesulphonyl, trichloromethane- sulphonyl, trifluoro-methanesulphonyl, 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 (DR'_n-R-Y) is formed in situ by reaction of an aminoalcohol compound (R'₂NR-0H) with, successively, 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 DR'_n-R-Y where Y is Br or I are usually carried out at a temperature between -20 and 20°C. Reactions with DR'_n- R-Y where 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 solvent. After the reaction with a compound according to the formula (X-R-Sul), a reaction with LiDR'_n or HDR'_n is carried out to replace X by a DR'„ functionality. This is done by means of a reaction carried out at 20 to 80°C, optionally in a similar solvent as mentioned above.

The synthesis of metal complexes using the specific pd compounds described above as ligand can be carried out using the processes known per se for this. The use of these pd compounds does not necessitate any adaptation of these known processes.

The polymerization of α-olefins, for example ethylene, propylene, butene, hexene, octene and mixtures thereof and with dienes, can be carried out in the presence of the metal complexes with the cyclo- pentadienyl compounds according to the invention as ligand. Particularly suitable for this purpose are the complexes of transition metals, not in their highest valency state, in which just one of the cyciopentadienyl 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 necessitate any essential adaptation of these processes. The known polymerizations are carried out in suspension, solution, emulsion, gas phase or as bulk polymerization. An organometallic compound is normally used as co-catalyst, the metal being chosen from groups 1, 2, 12 or 13 of the Periodic System of the Elements. Mention may be made, for example, of trialkylaluminium, alkylaluminium halides, alkylaluminoxanes (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 to be used in the polymerization may also be used as dispersant or solvent.

The invention will be explained on the basis of the following examples, without being limited thereto.

Experimental:

Reactions were monitored with the aid of gas chromatography (GC type: Hewlett Packard 5890 Series II, provided with autosampler type HP6890 Series Injector, integrator type HP3396A and HP Crosslinked Methyl Silicon Gum (25 m x 0.32 mm x 1.05 μm) column with one of the following temperature programmes: 50°C (5 min), rate: 7.5°C/min, 250°C (29 minutes) or 150°C (5 min), rate: 7.5°C/min. 250°C (29 minutes). The products were characterized using GC-MS (type

Fisons MD800, equipped with a quadrupole mass detector, Fisons AS800 autoinjector and CPSilδ column (30 m x 0.25 mm x 1 μm, low bleed) using one of the following temperature programmes: 50°C (5 min), rate: 7.5°C/min, 250°C (29 minutes) or 150°C (5 min), rate: 7.5°C/min, 250°C (29 minutes) and NMR Bruker ACP200 NMR ( ^λE = 200 MHz; ¹³C = 50 MHz) or Bruker ARX400 (^XH = 400 MHz; ¹³C = 100 MHz). Complexes were characterized using a Kratos MS80 mass spectrometer or a Finnigan Mat 4610 mass spectrometer.

Example I

Example Ia: Preparation of 6,6-dimethyl-l,3- cyclohexadiene 200 mL of dry diethylether was added to 50.7 g of dimedon (0.36 mol), followed by cooling to O'C. To the suspension thus obtained a suspension of lithium aluminiumhydride (12.8 g; 0.337 mol) in dry diethylether was added. Then the ice bath was removed and stirring took place for 2 hours at room temperature, after which another slurry, of 7.5 g lithiumaluminiumhydride in diethylether, was added. Subsequently, refluxing took place for 2 hours. After 18 hours' stirring at room temperature the reaction mixture was quenched with, successively, 20 mL of water, 20 mL of NaOH (15%) and 60 mL of water. The precipitate formed was filtered off and washed with 4 x 50 mL of diethylether. The filtrate was dried over magnesium sulphate. The drying agent was filtered off and the filtrate evaporated down on the rotary evaporator. 32.0 g of a yellow, liquid residue was obtained. This crude diol was transferred to a distillation set-up, after which 10 mL of H₂S0₄ was added. This was followed by vigorous stirring and heating for 2 hours to 130 'C. The fraction coming out at the top at 83-85 ^"C was collected. This fraction, consisting of a clear, colourless top layer and a grey, turbid bottom layer, was diluted with 150 mL of diethylether and extracted with, successively, 100 mL of Na₂C0₃ (10 %) and 2x 100 mL of water. Then the diethylether layer was dried over magnesium sulphate. After the drying agent had been filtered off, the filtrate was evaporated down on the rotation evaporator, at 45^*C and at atmospheric pressure. A colourless, clear residue was obtained, which was distilled under vacuum at room temperature. In a cold trap a colourless, clear liquid was collected.

Yield: 11.4 g of crude 6,6-dimethyl-l, 3-cyclohexadiene

1H-NMR(CDC1₃) : S = 5.6 (m, CH, 4H) ; 2.05 (d, CH₂, 2H) ; 0.90 (s, CH₃, 6H)

GC and GCMS:t_r = 9.326 ; 60% ; M = 108 : 6,6-dimethyl- 1, 3-cyclohexadiene t_r = 10.168 ; 12% ; M = 110 : 3,3-dimethyl-l- cyclohexene t_r = 10.385 ; 19% ; M = 110 : 6,6-dimethyl-3- cyclohexene

Example lb: Preparation of 3-(dimethylaminoethyl)-6,6- dimethyl-l,4-cyclohexadiene 6.9 g of potassium-tertiary-butoxide (62 mmol) was dissolved in 100 mL of dry diethylether and cooled to -70'C. Subsequently, 6,5 g of crude 6,6- dimethyl-1,3-cyclohexadiene was added. 37.0 mL of BuLi in hexane, 1.6 M (59 mmol) was added dropwise to this reaction mixture. After the reaction mixture had reach room temperature, it had turned into a yellow suspension. Subsequently, 8.3 g of 2- (dimethylamino)ethylchloride'HCl (58 mmol), which had first been freed of all HCl by means of BuLi, was added dropwise to the "anion mixture" at -70^*. Stirring took place for 18 hours at room temperature, after which the mixture was a dark beige suspension. The mixture was then cooled to O'C, quenched with methanol and filtered over a fluted filter and washed with diethylether. The filtrate was evaporated down and petroleum ether was added to the dark brown, liquid residue, which was then stirred and filtered over a P4 glass filter. The filtrate was evaporated down on the rotary evaporator and a brown, syrupy mixture remained behind. This residue was distilled under vacuum and the fraction that came out at the top at 59-60"C was collected. The product was a colourless, clear liquid.

Yield: 2.5 g of 3-(dimethylaminoethyl)-6,6-dimethyl- 1,4-cyclohexadiene

1H-NMR (CDC1₃) : δ = 5.47 (s, CH, 4H) ; 2.65 (t, CH, IH); 2.30-2.10 (t, CH2, 2H) and (s, CH3, 6H) ; 1.50 (m, CH2, 2H); 0.95 (s, CH₃, 6H) .

Example lc: Preparation of 3-(dimethylaminoethyl)-6,6- dimethylcyclohexadienyltitaniumdichloride 0.31 g of potassium-tertiary-butoxide (2.8 mmol) was dissolved in 10 mL of dry THF, followed by cooling to -70'C. Then, 0.5 g (2.79 mmol) of 3- (dimethylaminoethyl)-6,6-dimethyl-l,3-cyclohexadiene was added. To this reaction mixture 1.75 mL of n-BuLi in hexane (1.6 M, 2.8 mmol) was added dropwise. After the reaction mixture had reached room temperature, stirring was continued for another hour. Subsequently, at -70^* 1.03 g of solid TiCl₃-3THF was added, after which stirring took place for 18 hours at room temperature. The THF was removed, following which 10 mL of petroleum ether was added. After stirring for some time, this was also removed under reduced pressure. After proper drying 1.0 g of a green-brown solid remained which contained 3-(dimethylaminoethyl)-6,6- dimethylcyclohexa-dienyltitaniumdichloride, which was demonstrated by means of direct inlet MS.

Claims

C L A I M S

Substituted pentadiene compound according to the formula

where R^1-2 are substituents and at least one R²- substituent has the form RDR'_n, where D is a hetero atom from group 15 or 16 of the Periodic System of the Elements, R' is a substituent on the hetero atom, R is a linking group.

2. Compound according to claim 1, characterized in that two R¹ groups together form a dimethylmethylene group.

3. Process for the synthesis of a dienyl compound according to either of claims 1-2 by deprotonating a dienyl compound by reaction with a base, sodium or potassium and then allowing the anion formed to react with a compound according to the formula (DR'_n-R-Y), where R is a linking group, R' is a substituent,

D is an electron-donating hetero atom from group 15 or 16 of the Periodic System of the Elements, n is the number of R' groups bound to D, and Y is a halogen atom (X) or a sulphonyl group (Sul).

4. Process for the synthesis of a dienyl compound according to either of claims 1-2 by deprotonating a dienyl compound by reaction with a base, sodium or potassium and then allowing the anion formed to react with a compound according to the formula (X-

R-Sul), where

R is a linking group, X is a halogen atom, and

Sul is a sulphonyl group, after which a reaction with LiDR'_n or HDR'_n is carried out, where

D is an electron-donating hetero atom from group 15 or 16 of the Periodic System of the Elements,

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

5. Use of a dienyl compound according to either of claims 1-2 as ligand in a metal complex.

6. Use of a metal complex according to claim 5 for the polymerization of an olefin.