Polymerization catalysts containing beta-diketiminate-ligands

The present invention relates to transition metal complexes of the general formula I.         L_mMX_n     I, in which the variables have the following meaning:<dl id="dl0001"><dt>M</dt><dd>Titanium, zirconium, hafnium, vanadium, niobium, tantalum or a rare earth metal,</dd><dt>X</dt><dd>Fluorine, chlorine, bromine, iodine, hydrogen, c₁-c₁₀-Alkyl, C₆-C₁₅-Aryl or OR¹,</dd><dt>R¹</dt><dd>C.₁-C₁₀-Alkyl, C₆-C₁₅Aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,</dd><dt>m</dt><dd>1 or 2,</dd><dt>n</dt><dd>if M is titanium, zirconium or hafnium, a number 4-m, or, if M is vanadium, niobium or tantalum, a number 5-m, or, in the case that M represents a rare earth metal, a number 3-m, and</dd><dt>L</dt><dd>a ligand of the general formula II<chemistry id="chem0001" num="0001"><img file="EP0803520B1_D0001.tif" /></chemistry> in which A is a bridge member which, together with the nitrogen and carbon atom to which it is attached, forms a five- or six-membered, optionally substituted, aromatic ring which may also contain two further heteroatoms from the group consisting of oxygen, sulfur and nitrogen and with one can be fused to another two-, three-, or tetranuclear iso- or heteroaromatic system, R²  Hydrogen, C₁-C₁₀-Alkyl, C₆-C₁₅-Aryl, tri- (C₁-C₁₀) alkylsilyl or tri- (C₆-C₁₅) arylsilyl, R³  C.₆-C₁₅-Aryl or C₁-C₁₀-Alkyl residues, which carry no hydrogen on the α-C atom and R⁴  Hydrogen, C₁-C₁₀-Alkyl, C₆-C₁₅-Aryl, tri- (C₁-C₁₀) alkylsilyl or tri- (C₆-C₁₅) arylsilyl</dd></dl> mean.

The invention further relates to a process for the preparation of the transition metal complexes, β-diketimines, the anions of which serve as ligands for the transition complexes, the use of the transition metal complexes as catalysts for the polymerization of olefins, a process for the preparation of polymers with the aid of these transition metal complexes, the use of the polymers for the production of fibers, films and moldings and such fibers, films and moldings themselves.

Transition metal complexes of elements of subgroup 4 of the periodic table have long been used as catalysts for olefin polymerization. For example, Ziegler catalysts and metallocene catalysts are known (see, for example, Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol. A21, pp. 502-504 (1992)). Transition metal complexes with other ligand systems have also been used as catalysts, such as azaallyl (WO 95/33776) and β-diketiminate complexes (J. Organometall. Chem.,<u>500</u>, 203-217 (1995)). However, the known catalyst systems still leave something to be desired in terms of their product specificity, in particular with regard to the chain length of the polymers.

The object of the present invention was therefore to provide new transition metal complexes which are suitable as catalysts for olefin polymerization and overcome the disadvantages of the known catalysts.

Accordingly, the transition metal complexes mentioned at the outset have been found.

In addition, a process for the preparation of the transition metal complexes, β-diketimines, the anions of which serve as ligands for the transition complexes, the use of the transition metal complexes as catalysts for the polymerization of olefins, a process for the preparation of polymers with the aid of these transition metal complexes, the use of the polymers for the preparation of fibers, films and moldings as well as such fibers, films and moldings themselves found.

Among the transition metals M in general formula I, the elements of subgroup 4 of the periodic table are preferred, zirconium being particularly preferred.

The halogens fluorine, chlorine, bromine and iodine are particularly to be mentioned as ligands X, chlorine being particularly preferred. Among the C₁-C₁₀Alkyl radicals are particularly suitable for methyl, ethyl, propyl and butyl. Preferred C₆-C₁₅-Aryl radical is the phenyl radical.

The numbers m and n complement each other to the value of the respective transition metal central atom. The meaning of m is preferably 1, since transition metal complexes with a β-diketiminate ligand show particularly good catalytic activity. This applies in particular to the metal complexes of titanium and zirconium. In the production of the transition metal complexes, however, a complex with m = 2 is usually obtained first, which is then in a comproportionation reaction with MX_{n + m} to complex L₁MX_n is implemented.

As residues R² in ligand L of the general formula II, for example, the alkyl radicals methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl and the various isomers of pentyl, hexyl, heptyl, octyl, nonyl and decyl into consideration.

Furthermore come as R² C.₆-C₁₅Aryl radicals, in particular phenyl or naphthyl radicals which are unsubstituted or substituted by alkyl radicals from the above-mentioned group.

As further residues R² are hydrogen, triphenylsilyl and trimethylsilyl.

As residues R³ unsubstituted or methyl, ethyl or halogen-substituted phenyl radicals are particularly suitable, particularly preferably p-methylphenyl and pentafluorophenyl. Among the C₁-C₁₀-Alkyl radicals that do not have a hydrogen atom on the α-C atom should be mentioned in particular tert-butyl.

As residues R⁴ the same residues come into consideration as for R² were mentioned, preferably trialkylsilyl or triarylsilyl radicals, particularly preferably trimethylsilyl.

The bridge link A supplements the grouping〉 C = N- to a five- or six-membered ring system. This ring system can also carry two further heteroatoms, so that, for example, ring systems from the pyridine, pyridazine, pyrimidine, pyrazine, triazine, pyrrole, pyrazole, thiazole or oxazole series are present. These ring systems can also be fused with a further two-, three- or four-ring isoaromatic or heteroaromatic system, so that, for example, ring systems from the indole, indazole, quinoline, isoquinoline or quinazoline series are present.

The bridge member A preferably supplements the grouping〉 C = N- to form a pyridine, quinoline or isoquinoline ring system.

Transition metal complexes in which A is a bridge member of the general formula III are preferred<chemistry id="chem0002" num="0002"><img file="EP0803520B1_D0002.tif" /></chemistry> means in which the substituents<dl id="dl0002"><dt>R⁵, R⁶, R⁷, R⁸</dt><dd>Hydrogen, C₁-C₁₀-Alkyl, C₆-C₁₅Aryl or corresponding substituents bonded via oxygen, sulfur, nitrogen or phosphorus, nitro or nitroso</dd></dl> mean.

The substituents R⁵, R⁶, R⁷ and R⁸ are preferably hydrogen. Examples of alkyl and aryl radicals are those listed under R² mentioned residues into consideration. Also suitable are substituents in which hydrogen or the above-mentioned alkyl or aryl radicals are bonded via oxygen, sulfur, nitrogen or phosphorus, such as alkoxy, alkylthio, monoalkylamino, dialkylamino, dialkylphosphino, aryloxy, arylthio, monoarylamino, diarylamino or diarylphosphino.

Transition metal complexes in which A is a bridge member of the general formula IV are also preferred<chemistry id="chem0003" num="0003"><img file="EP0803520B1_D0003.tif" /></chemistry> means in which the substituents R⁵, R⁶, R⁷ and R⁸ the meaning given above and R⁹ and R¹⁰ also have this meaning.

For the substituents R⁹ and R¹⁰ the same preferences apply as for the R radicals⁵ and R⁸ were called.

For the preparation of the transition metal complexes according to the invention, a process has been found which is characterized in that a compound of the general formula V<chemistry id="chem0004" num="0004"><img file="EP0803520B1_D0004.tif" /></chemistry> with a strong base in the anion Va<chemistry id="chem0005" num="0005"><img file="EP0803520B1_D0005.tif" /></chemistry> transferred with a nitrile R³-CN to anion IIa<chemistry id="chem0006" num="0006"><img file="EP0803520B1_D0006.tif" /></chemistry> if necessary, the protective group (CH₃)₃Si by implementation with a compound R⁴-Halogen replaced and the anion II thus obtained<chemistry id="chem0007" num="0007"><img file="EP0803520B1_D0007.tif" /></chemistry> with transition metal compounds of the formula MX_{m + n} implements.

The starting compounds V can be obtained in a known manner. The production is described, for example, in J. Chem. Soc., Dalton Trans.<u>1990</u>, 1161.

For example, butyl lithium can serve as a strong base for converting V into the anion Va. (The counterion, in this case Li^⊕was not listed in the formula scheme for reasons of clarity).

The reaction conditions are not critical per se.

Production in a hexane-diethyl ether mixture as a solvent at approx. 20 ° C. under a protective gas atmosphere made of nitrogen or argon has proven particularly suitable.

By protonation, for example in the presence of water, the β-diketimines of the general formula IIb can be obtained from the anions II<chemistry id="chem0008" num="0008"><img file="EP0803520B1_D0008.tif" /></chemistry> in which the variables have the meaning given above. These β-diketimines are stable on storage and represent valuable intermediates for the preparation of the transition metal complexes according to the invention.

The transition metal complexes according to the invention are used as catalysts for the polymerization of olefins.

Preferred polymerizable olefins are ethylene, propylene, but-1-ene, pent-1-ene, hex-1-ene, oct-1-ene and mixtures of these olefins.

The process according to the invention for the preparation of polymers of C.₂-C₁₀-Alk-1-enes at pressures from 0.5 to 3000 bar and temperatures from -50 to 300 ° C using a catalyst system is characterized in that the catalyst system as active components<ul id="ul0001" list-style="none"><li>a) transition metal complexes according to formula I.         L_mMX_n     I, and</li><li>b₁) an open-chain or cyclic alumoxane compound of the general formulas VI or VII<chemistry id="chem0009" num="0009"><img file="EP0803520B1_D0009.tif" /></chemistry><chemistry id="chem0010" num="0010"><img file="EP0803520B1_D0010.tif" /></chemistry>    in the R¹¹ a C₁-C₄-Alkylgruppe means and o stands for a number from 5 to 30 and or</li><li>b₂) contains cation-forming compounds.</li></ul>

The rest R¹¹ is preferably methyl or ethyl, o is preferably a number from 10 to 25.

The oligomeric alumoxane compounds are usually prepared by reacting a solution of trialkyl aluminum with water and are described, inter alia, in EP-A 284 708 and US Pat. No. 4,794,096.

As a rule, the oligomeric alumoxane compounds obtained are mixtures of different lengths, both linear and cyclic chain molecules, so that m is to be regarded as the mean. The alumoxane compounds can also be present in a mixture with other metal alkyls, preferably with aluminum alkyls.

It has proven advantageous to use the transition metal complexes according to the invention and the oligomeric alumoxane compound in amounts such that the atomic ratio between aluminum from the oligomeric alumoxane compound and the transition metal is in the range from 10: 1 to 10⁶: 1, especially in the range of 10: 1 to 10⁴: 1, lies.

Suitable cation-forming compounds are in particular strong, neutral Lewis acids, ionic compounds with Lewis acid cations and ionic compounds with Bronsted acids as the cation.

Compounds of the general formula VII are strong, neutral Lewis acids         M¹X¹X²X³     VII preferred in the<dl id="dl0003"><dt>M¹</dt><dd>an element of III. Main group of the periodic table means, in particular B, Al or Ga, preferably B,</dd><dt>X¹, X² and X³</dt><dd>for hydrogen, C₁- to C₁₀-Alkyl, C₆- to C₁₅Aryl, alkylaryl, arylalkyl, haloalkyl or haloaryl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical or fluorine, chlorine, bromine or iodine, in particular for haloaryls, preferably for pentafluorophenyl.</dd></dl>

Compounds of the general formula VII in which X¹, X² and X³ are the same, preferably tris (pentafluorophenyl) borane.

Compounds of the general formula VIII are ionic compounds with Lewis acid cations         [(Y^{a +}) Q₁Q₂... Q_e.g.]^{d +}     VIII suitable in which<dl id="dl0004"><dt>Y</dt><dd>an element of I. to VI. Main group or the I. to VIII. Subgroup of the periodic table means</dd><dt>Q₁ to Q_e.g.</dt><dd>for simply negatively charged residues like C₁- to C₂₈-Alkyl, C₆- to C₁₅Aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl each having 6 to 20 C atoms in the aryl and 1 to 28 C atoms in the alkyl radical, C₁- to C₁₀-Cycloalkyl, which is optionally with C₁- to C₁₀-Alkyl groups can be substituted, halogen, C₁- to C₂₈-Alkoxy, C₆- to C₁₅Aryloxy, silyl or mercaptyl groups</dd><dt>a</dt><dd>stands for integers from 1 to 6</dd><dt>e.g.</dt><dd>for integers from 0 to 5</dd><dt>d</dt><dd>corresponds to the difference az, but d is greater than or equal to 1.</dd></dl>

Carbonium cations, oxonium cations and sulfonium cations as well as cationic transition metal complexes are particularly suitable. The triphenylmethyl cation, the silver cation and the 1,1'-dimethylferrocenyl cation should be mentioned in particular. They preferably have non-coordinating counterions, in particular boron compounds, as they are also mentioned in WO 91/09882, preferably tetrakis (pentafluorophenyl) borate.

Ionic compounds with Bronsted acids as cations and preferably also non-coordinating counterions are mentioned in WO 91/09882, the preferred cation is N, N-dimethylanilinium.

The amount of cation-forming compounds is preferably 0.1 to 10 equivalents, based on the transition metal complex I.

Conventional aromatic hydrocarbons are used as solvents for these catalyst systems, preferably with 6 to 20 carbon atoms, in particular xylenes and toluene and mixtures thereof.

In the preparation of the polymers of C₂- to C₁₀-Alk-1-enes, a supported catalyst system can also be used. Suitable carrier materials are, for example, silica gels, preferably those of the formula SiO₂ A Al₂O₃, where a is a number in the range from 0 to 2, preferably 0 to 0.5; So these are aluminosilicates or silicon dioxide. The carriers preferably have a particle diameter in the range from 1 to 200 μm, in particular from 30 to 80 μm. Products of this type are commercially available, for example Silica Gel 332 from Grace.

Among polymers of C₂- to C₁₀-Alk-1-enes are homo- or copolymers of C₂- to C₁₀-Alk-1-enes, especially from C₂- to C₆-Alk-1-enes to understand. Homopolymers of ethylene or propylene and copolymers of ethylene and propylene, ethylene and but-1-ene, ethylene and pent-1-ene, ethylene and hex-1-ene and propylene and but-1-ene, propylene and pent are preferred -1-enes as well as propylene and hex-1-enes. The proportion of comonomers can be up to 50% by weight, in particular up to 30% by weight.

The process according to the invention can be carried out both in solution, in a suspension, in the gas phase or as bulk polymerization. The process for the preparation of the polymers of C₂-C₁₀-Alk-1-enes carried out in the gas phase. The polymerization conditions are not critical per se; Pressures from 0.5 to 3000 bar, preferably from 1 to 80 bar and temperatures from -50 to + 300 ° C, preferably from 0 to 150 ° C, have proven to be suitable. The polymerization can be carried out in the presence of conventional regulators, for example hydrogen or C.₂-C₈-Alk-1-enes and in conventional polymerization reactors.

In a preferred process for the preparation of homopolymers of C₂- to C₁₀-Alk-1-enes is carried out in such a way that the active constituents of the catalyst system are introduced in toluene at temperatures in the range from 0 to 140.degree.

For this, the C. Is then over a period of 0.5 to 12 hours₂- to C₁₀-Alk-1-en pressed at a pressure of 1 to 60 bar. The polymers are then worked up using customary methods.

The process according to the invention for the preparation of polymers of C.₂- to C₁₀-Alk-1-enen is characterized by low procedural complexity.

The polymers of C₂- to C₁₀-Alk-1-enes have a balanced property profile. The polymers in particular have very high molecular weights and are particularly suitable for the production of fibers, films and moldings.

Examples

example 1

Synthesis of [Li {N (SiMe

3

) C (Ph) C (H) (C

5

H

4

N-2)}]

2

[Li {CH (SiMe₃) (C₅H₄N-2)}]₂ was made up by 5.13 g (31 mmol) CH₂(SiMe₃) (C₅H₄N-2) were added at room temperature to a solution of n-butyl lithium (32 mmol) in 20 ml of hexane and 20 ml of diethyl ether. After stirring the reaction mixture for 30 min at room temperature, the suspension was diluted with 35 ml of diethyl ether. 3.3 ml (32 mmol) of benzonitrile was added dropwise at room temperature. The reaction mixture was stirred for 16 h, then the volatiles were removed in vacuo. The residue was dried at 50 ° C in a vacuum. Crystals were obtained by slowly cooling a hot hexane solution (50 ml) to 0 ° C. Yield: 2.89 g (34%)

¹H NMR (360 MHz, C₆D₆): δ 8.05 (m, 1H, py), 790 (d, J = 7.4 Hz, 2H, Ph), 7.29 (t, J = 7.4, 2H, pH), 7.20 (d, J = 7.2, 1H, py ), 6.99 (t, J = 7.8, 1H, pH), 6.73 (d, J = 7.9 Hz, 1H, py), 6.41 (ps, t, 1H, py), 6.24 (s, 1H, CH), - 0.02 (s, 9H, SiMe₃). ¹³C NMR (62.9 MHz, C₆D₆/ C₆D₆): δ 165.3 (NCPh), 160.5, 148.5, 147.2, 137.3, 129.2, 128.2, 127.9, 124.1 and 117.6 (aryl C), 107.1 (CH), 2.5 (SiMe₃).

Example 2

Synthesis of [Li {N (SiMe

3

) C (Ph) C (SiMe

3

) (C

5

H

4

N-2)}]

2

[Li {C (SiMe₃)₂(C.₅H₄N-2)}]₂ was prepared by adding 8.0 ml (7.4 g, 31 mmol) CH (SiMe₃)₂(C.₅H₄N-2) were added at room temperature to a solution of n-butyl lithium (32 mmol) in 20 ml of hexane and 50 ml of diethyl ether. The reaction mixture was stirred for 1 h at room temperature. 3.2 ml (31 mmol) of benzonitrile was added dropwise at room temperature. The reaction mixture was stirred for 15 h, then the volatiles were removed in vacuo. The residue was suspended in 50 ml of hexane, cooled to -30 ° C and then collected on a frit. The product was washed with 30 ml of pentane. Yield: 7.37 g (68%)

¹H NMR (250 MHz, C₄D₈O): δ 8.13 (ddd, J = 5.2, 2.0, 0.9 Hz, 1H, py), 7.38 (ddd, J = 8.3, 7.1, 2.0 Hz, 1H, py), 7.33-7.29 (m, 2H, Ph) , 7.18-7.15 (m, Ph), 7.11 (dt, J = 8.3, 1.0 Hz, 1H, py), 6.68 (ddd, J = 7.1, 5.2, 1.2 Hz, 1H, py), -0.36 (s, 9H , SiMe₃), -0.41 (s, 9H, SiMe₃). ¹³C NMR (62.9 MHz, C₄D₈O): δ 174.2 (NCPh), 167.0, 151.5, 146.4, 135.0, 130.8, 127.6, 127.2, 125.8 and 115.7 (aryl C), 99.0 (CSiMe₃), 3.8 (SiMe₃).

Example 3

Synthesis of [Li {N (SiMe

3

) C (Ph) C (SiMe

3

) (c

9

H

6

N-2)}]

2

CH₂(SiMe₃) (C₉H₆N-2) (0.9 ml, 4.1 mmol) were added dropwise at 0 ° C. to a solution of n-butyl lithium (2.5 ml, 4.0 mmol) in hexane, diluted with 5 ml of diethyl ether . The solution was stirred for 30 min at room temperature; then 0.5 ml (4.0 mmol) of SiMe₃Cl added. After stirring for 15 hours at room temperature, the suspension was filtered and mixed with 2.4 ml (3.8 mmol) of n-butyl lithium at 0 ° C. The solution was stirred for 15 min at room temperature, then 0.4 ml (3.9 mmol) benzonitrile was added at 0 ° C. After the reaction mixture was stirred for 15 h, the volatile constituents were removed in vacuo and the residue was dried in vacuo at 50 ° C. for 30 min. The residue was washed twice with 10 ml of hexane each time. Yield: 1.02 g (64%)

¹H NMR (250 MHz, C₄D₈O): δ 7.80 (t, J = 9.0 Hz, 2H, qui), 7.60 (dd, J = 7.9, 1.2 Hz, 1H, Ph), 7.45 (m, 1H, Ph), 7.34 (m, 3H, aryl H), 7.20 (m, 4H, aryl H), -0.32 (s, 9H, SiMe₃), -0.38 (s, 9H, SiMe₃) ¹³C NMR (62.9 MHz, C₄D₈O): δ 174.8, (NCPh), 167.7, 151.2, 148.6, 133.7, 130.9, 128.5, 128.0, 127.7, 127.5, 127.4, 126.8, 125.9 and 123.2 (aryl C), 100.6 (CSiMe₃), 4.1 (SiMe₃), 3.8 (SiMe₃).

Example 4

Synthesis of Zr {N (SiMe

3

) C (Ph) C (H) (C

5

H

4

N-2)}

2

Cl

2

A solution of 2.38 g (4.34 mmol) of example compound 1 in 12 ml of THF became a solution of 0.99 g (4.25 mmol) of ZrCl₄ placed in 60 ml THF at 0 ° C. The reaction mixture was allowed to warm to room temperature, then stirred for 15 h and then refluxed for 1.5 h. The volatile constituents were removed in vacuo and the residue was extracted with 10 ml of hexane, 50 ml of diethyl ether and dichloromethane (2x25 ml). The combined extracts were concentrated to 50 ml and then cooled to -30 ° C. The crystals thus obtained were washed with 5 ml of hexane. Yield: 1.58 g (53%).

¹H NMR (360 MHz, C₆D₆): δ 9.04 (d, J = 6.0 Hz, 2H, py), 7.66 (d, J = 7.2 Hz, 4H, Ph), 7.1-7.0 (m, 6H, Ph), 6.77 (t, J = 7.7 Hz , 2H, py), 6.35 (d, J = 7.9 Hz, 2H, py), 6.30 (t, J = 6.6, 2H, py), 6.05 (s, 2H, CH), 0.21 (s, 18H, SiMe₃). ¹³ C NMR (62.9 MHz, C₆D₆): δ 155.0 (NCPh), 154.2, 149.8, 141.2, 138.0, 129.2, 128.8, 127.9, 123.3 and 120.2 (aryl C), 111.2 (CH), 3.1 (SiMe₃).

Example 5

Synthesis of Zr {N (SiMe

3

) C (Ph) C (SiMe

3

) (C

5

H

4

N-2)}

2

Cl

2

To a solution of 1.33 g (5.71 mmol) of ZrCl₄ 3.86 g (5.70 mmol) of example compound 2 were added to 60 ml of diethyl ether. The reaction mixture was stirred for 16 h, then the volatiles were removed in vacuo. The residue was extracted with 2x50 ml dichloromethane and filtered off twice. The volatile constituents were removed in vacuo and the residue was recrystallized from 50 ml of toluene at -30 ° C. Yield: 1.32 g (1.57 mmol). Concentration of the mother liquor gave a further 1.13 g of product. Overall yield: 2.45 g (54%).

¹H NMR (360 MHz, C₆D₆): δ 8.59-8.58 (m, 2H, py), 7.68 (D, J = 5.7 Hz, 2H, Ph), 7.63 (d, J = 6.6 Hz, 2H, Ph), 7.28 (d, J = 8.1 Hz , 2H, py), 7.12 (m, 6H, Ph), 6.87 (td, J = 7.7 Hz, 1.7 Hz, 2H, py), 6.00 (t, J = 6.0 Hz, 2H, py), 0.03 (s, 18H, SiMe₃), 0.01 (s, 18H, SiMe₃). ¹³C NMR (62.9 Hz, C₆D₆): δ 165.0 (NCPh), 162.9, 149.8, 143.4, 137.9, 130.4, 129.3, 128.6, 128.4, 128.3, 127.9, 127.0 and 125.8 (aryl C), 118.6 and 118.3 (CSiMe₃), 4.3 and 2.3 (SiMe₃).

Example 6

Synthesis of Zr {N (SiMe

3

) C (Ph) C (SiMe

3

) (2-C

9

H

6

N)}

2

Cl

2

To a suspension of 0.5 g (2.2 mmol) ZrCl₄ 1.7 g (4.3 mmol) of example compound 3 were added to 50 ml of diethyl ether. The reaction mixture was stirred for 3 h then the volatiles were removed in vacuo. The residue was extracted with 45 ml of warm toluene and filtered off. The filtrate was evaporated to dryness in vacuo and the residue was extracted with 25 ml of hexane. The solid was recrystallized from a mixture of dichloromethane and diethyl ether (1: 1, v: v). Yield: 0.78 g (37%).

¹H NMR (360 MHz, C₆D₆): δ 8.82 (d, J = 8.3 Hz, 2H, qui), 8.28 (d, J = 8.4 Hz, 2H, qui), 7.80 (d, = 6.9 Hz, 2H, Ph), 7.54 (d, J = 8.6 Hz, 2H, Ph), 7.26-7.17 (m, 8H, Ph and qui), 6.77-6.75 (m, 2H, qui, 6.60-6.57 (m, 4H, qui), 0.09 (s, 18H, SiMe₃), 0.08 (s, 18H, SiMe₃). ¹³C NMR (62.9 MHz, C₆D₆/ C₆H₆): δ 166.5 (NCPh), 163.5, 145.8, 142.8, 138.7, 135.1, 131.5, 130.7, 129.8, 127.3, 126.9, 126.5, 124.9, 119.5 and 118.4 (aryl C), 104.9 (CSiMe₃), 3.9 and 2.6 (SiMe₃).

Example 7

Synthesis of Zr {N (SiMe

3

) C (Ph) C (SiMe

3

) (2-C

9

H

6

N)} Cl

3

To a suspension of 0.63 g (2.7 mmol) ZrCl₄ 2.16 g (2.57 mmol) of example compound 5 were added to 35 ml of toluene. The reaction mixture was stirred for 16 h, then the volatiles were removed in vacuo. The residue was extracted with 20 ml of hexane. Yield: 1.73 g (3.22 mmol), 63%).

¹H NMR (360 MHz, CD₂Cl₂): δ 8.88 (d, J = 5.4 Hz, 1H, py), 8.36 (t, J = 8.1 Hz, 1H, py), 7.29 (d, J = 8.1 Hz, 1H), 7.73-7.42 (6H, Ph and py), -0.09 (s, 9H, SiMe₃), -0.28 (s, 9H, SiMe₃).

Example 8

Synthesis of Zr {N (SiMe

3

) C (Ph) C (SiMe

3

) (2-C

9

H

6

N)} Cl

3

To a suspension of 0.39 g (1.67 mmol) ZrCl₄ 1.53 g (1.63 mmol) of example compound 6 were added to 25 ml of dichloromethane. The reaction mixture was stirred for 16 h, then it was filtered off and the filtrate was concentrated to 10 ml. Cooling the solution to -30 ° C gave 0.81 g of crystals. Further substance could be obtained from the mother liquor. Overall yield: 1.10 g (57%).

1H NMR (360 MHz, CD₂Cl₂): δ 8.80 (d, J = 8.7 Hz, 1H, qui), 8.75 (d, J = 8.4 Hz, 1H, qui), 8.0-7.5 (14H, Ph and qui), 7.40 (t, J = 7.5 Hz , 1H), 7.25 (t, J = 7.7 Hz, 1H), 6.95 (t, J = 7.3 Hz, 1H), 6.86 (t, J = 7.6 Hz, 1H), 6.65 (d, J = 8.4 Hz, 1H , qui), 6.34 (d, J = 8.6 Hz, 1H qui), 0.26 (s, 9H, SiMe₃), -0.10 (s, 9H, SiMe₃), -0.20 (s, 9H, SiMe₃), -0.31 (s, 9H, SiMe₃).

Example 9

Ethylene polymerization

In a typical experiment, 31 mg (0.053 mmol) of example compound 8 were reacted with 3.5 ml (5.4 mmol Al) of a 10% strength by weight solution of methylalumoxane (MAO) in toluene at room temperature. The solution was diluted with 31.5 ml of toluene, degassed and then placed under a pressure of 1.5 bar of ethylene at room temperature. After 30 minutes, the polymerization was stopped by adding methanolic HCl. The polymer was isolated, washed with 1 M HCl solution, water and methanol and then dried at 80 ° C to constant weight. Further examples carried out analogously are listed in Table 1.<tables id="tabl0001" num="0001"><table frame="all"><title>Table 1:</title><tgroup cols="7" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="22.50mm" /><colspec colnum="2" colname="col2" colwidth="22.50mm" /><colspec colnum="3" colname="col3" colwidth="22.50mm" /><colspec colnum="4" colname="col4" colwidth="22.50mm" /><colspec colnum="5" colname="col5" colwidth="22.50mm" /><colspec colnum="6" colname="col6" colwidth="22.50mm" /><colspec colnum="7" colname="col7" colwidth="22.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col7" align="left">Ethylene polymerization:</entry></row><row><entry namest="col1" nameend="col1" align="center">Catalyst according to the example</entry><entry namest="col2" nameend="col2" align="center">Weighed catalyst (mg)</entry><entry namest="col3" nameend="col3" align="center">MAO solution (ml)</entry><entry namest="col4" nameend="col4" align="center">added toluene (ml)</entry><entry namest="col5" nameend="col5" align="center">Response time (min)</entry><entry namest="col6" nameend="col6" align="center">Yield of PE (mg)</entry><entry namest="col7" nameend="col7" align="center">η value (dl / g)</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">4</entry><entry namest="col2" nameend="col2" align="center">50</entry><entry namest="col3" nameend="col3" align="center">5</entry><entry namest="col4" nameend="col4" align="center">20</entry><entry namest="col5" nameend="col5" align="center">60</entry><entry namest="col6" nameend="col6" align="center">10</entry><entry namest="col7" nameend="col7" align="center">11.2</entry></row><row><entry namest="col1" nameend="col1" align="center">7</entry><entry namest="col2" nameend="col2" align="center">41</entry><entry namest="col3" nameend="col3" align="center">5</entry><entry namest="col4" nameend="col4" align="center">45</entry><entry namest="col5" nameend="col5" align="center">25</entry><entry namest="col6" nameend="col6" align="center">620</entry><entry namest="col7" nameend="col7" align="center">9.1</entry></row><row><entry namest="col1" nameend="col1" align="center">8</entry><entry namest="col2" nameend="col2" align="center">31</entry><entry namest="col3" nameend="col3" align="center">3.5</entry><entry namest="col4" nameend="col4" align="center">32</entry><entry namest="col5" nameend="col5" align="center">25</entry><entry namest="col6" nameend="col6" align="center">150</entry><entry namest="col7" nameend="col7" align="center">7.3</entry></row><row rowsep="1"><entry namest="col1" nameend="col7" align="justify">The η values ​​were determined according to ISO 1628-3.</entry></row></tbody></tgroup></table></tables>