WO2004078765A2

WO2004078765A2 - Catalysts for the polymerization of styrene

Info

Publication number: WO2004078765A2
Application number: PCT/EP2004/002179
Authority: WO
Inventors: Jun Okuda; Klaus Möller; Valentine Reimer
Original assignee: Basf Aktiengesellschaft
Priority date: 2003-03-05
Filing date: 2004-03-04
Publication date: 2004-09-16
Also published as: WO2004078765A3; DE10309837A1

Abstract

The invention relates to bisphenolate ligand systems and related compounds, transition metal compounds containing said inventive ligand systems, a catalyst system for the polymerization of unsaturated compounds containing at least one inventive transition metal compound and at least one co-catalyst, a method for the production of polymers by polymerization or copolymerization of at least one unsaturated compound in the presence of an inventive catalyst system and the use of an inventive transition metal compound or an inventive catalyst system for the production of isotactic polystyrene.

Description

Catalysts for the polymerization of styrene

The present invention relates to novel ligand systems containing bridged heteroatoms, which have no cyclopentadienyl ligands, transition metal compounds containing these ligand systems, catalyst systems containing the transition metal compounds according to the invention and a cocatalyst, a process for the preparation of polymers by polymerization or copolymerization of at least one unsaturated compound in the presence of the catalyst system according to the invention and the Use of a transition metal compound according to the invention or a catalyst system according to the invention for the production of isotactic polystyrene.

Research and development on the use of organic transition metal compounds, in particular of metallocenes as catalyst components for the stereoselective polymerization of styrene or polymerization and copolymerization of olefins with the aim of producing tailor-made polyolefins, has been carried out intensively at universities and in industry over the past 15 years.

In addition to the metallocenes, new classes of transition metal compounds as catalyst components that do not contain cyclopentadienyl ligands are increasingly being investigated.

In J. Macromol. Chem. Phys. 1998, 199, 543 describe titanium complexes with a 2,2'-sulfur bridged bisphenolate ligand of the type Ti [OC ₆ H ₂ - ^t Bu-6-Me-4) ₂ S] X ₂ , which are used as transition metal components in the syndiospecific polymerization of Styrene can be used. Kakugo et al., Macromol. Chem., Macromol. Symp. 66, 203-214 (1993) relates to the use of titanium complexes containing thiobisphenoxy groups as polymerization catalysts. In combination with mefhylalumoxane as a cocatalyst, these catalysts are highly active in the polymerization of ethylene and propylene. Polypropylene is obtained with a high molecular weight but low stereoregularity. Furthermore, the catalysts are suitable for the polymerization of styrene, with highly hydrolytic polystyrene being obtained. The copolymerization of styrene with ethylene is also possible, forming strictly alternating polymers with isotactic polystyrene units.

According to the prior art, heterogeneous Ziegler-Natta catalysts are generally used to produce highly isotactic polystyrene.

Hiorns et al., Polymer 43 (2002) 3365-3369 relates to a process for the production of highly isotactic (> 99%) polystyrene with a high molecular weight and narrow molecular weight distribution. A classic Ziegler-Natta system is used as the catalyst. Ultrasound is used in the synthesis of the polymers.

Liao et al., Polymer 42 (2001) 4087-4090 relates to the production of isotactic polystyrene with heterogeneous modified Ziegler-Natta systems. With some systems, isotacticities of> 90% are achieved.

It is an object of the present invention to provide ligand systems and transition metal compounds based on nonmetallocenes which can be obtained therefrom and which are suitable as a constituent of catalyst systems for the production of isotactic polystyrene. Furthermore, the catalyst systems produced with these transition metal compounds should also be suitable for the polymerization and copolymerization of further α-olefins.

The tasks are solved by a

Ligand system of formula (I)

wherein

D, D 'can be the same or different and represents oxygen, sulfur, selenium, tellurium, an NR ¹¹ group or PR ^π group,

Y, Y 'can be the same or different and represents oxygen, sulfur, selenium, tellurium, an NR ¹ ^ group or PR ¹ ^ group,

Is 0 or 1,

1 9

R, R can be the same or different and are hydrogen or a Ci-C ^ - carbon-containing radical, or two radicals R ¹ and R ² together with the carbon atom connecting them or, if q> 1, two radicals R ¹ together form a cyclic or polycyclic ring system with the C atoms connecting them, which in the ring system can contain, in addition to carbon atoms, one or more identical or different heteroatoms selected from the group consisting of the elements N, O, P, S and Si,

is an integer from 1 to 10, R to R may be the same or different and are hydrogen or a -C-C ₄₀ - carbon-containing radical, or two adjacent radicals R ³ to R ¹⁰ together with the atoms connecting them form a cyclic or polycyclisch.es ring system which in addition to the ring system

Carbon atoms can contain one or more, identical or different heteroatoms selected from the group consisting of the elements N, O, S and Si.

R ^{11 is} hydrogen or a Cι _. -C ₄₀ -Carbon residue.

The ligand system according to the invention is suitable for the production of transition metal compounds based on nonmetallocenes, which are suitable as a component of catalyst systems for polymerizing unsaturated compounds.

D, D 'are the same or different and are preferably oxygen, sulfur, an NR ^U group or a PR ¹¹ group, particularly preferred is at least D or D' oxygen, very particularly preferably both D and D 'are oxygen. Bis (phenol) compounds are therefore very particularly preferred as ligand systems of the formula I.

Y, Y 'are the same or different and are preferably oxygen, sulfur, an NR ^π group or a PR ^π group, at least Y or Y' is particularly preferred, both Y and Y 'being very particularly preferred.

p is 0 or 1. If p is 1, these are symmetrical complexes which are particularly suitable for the preparation of transition metal compounds which are suitable for the preparation of isotactic styrene or copolymers which contain isotactic polystyrene units. If p is 0, these are unsymmetrical complexes which are particularly suitable for the polymerization of further unsaturated compounds. In a preferred embodiment, R ¹ , R ² are, independently of one another, hydrogen or a Ci-Cio-, particularly preferably C to C ₃ -, very particularly preferably Ci- to C ₂ - carbon-containing radical or two radicals R ¹ and R ² together form the C atom connecting them or, if q> 1, two radicals R ¹ together with the C atoms connecting them form a cyclic ring system which, in addition to carbon atoms, contains a hetero atom in the ring system, selected from the group consisting of the elements N, O and P may contain.

For the purposes of the present application, carbon-containing radicals are to be understood as meaning aliphatic, cycloaliphatic and aromatic radicals which may optionally contain heteroatoms such as N, O, S and Si, provided that these do not impair the polymerization with transition metal compounds prepared from the ligand system according to the invention. The aliphatic radicals can be branched or unbranched and the cycloaliphatic radicals can be substituted with further radicals, for example aliphatic C to C ₁₀ , preferably Ci to C ₄ , particularly preferably C to C ₂ radicals or aromatic radicals. Furthermore, the aliphatic and cycloaliphatic radicals can optionally be unsaturated, provided that these do not impair the polymerization with transition metal compounds prepared from the ligand system according to the invention. The carbon-containing radicals are particularly preferably branched or unbranched alkyl radicals having 1 to 10, preferably 1 to 4, particularly preferably 1 to 2

Carbon atoms.

R ¹ , R ² independently of one another are particularly preferably hydrogen or a Cr to Cio, preferably Cr to C ₃ , particularly preferably Cr to C ₂ alkyl radical. R ¹ and R ² are very particularly preferably independently of one another hydrogen or methyl. In a very particularly preferred embodiment, in particular when the ligand system is used to produce transition metal compounds which are used for the polymerization or copolymerization of styrene, both R ¹ and R ^{2 are} hydrogen.

q is preferably an integer from 1 to 5, particularly preferably 1, 2 or 3. In a preferred embodiment, R ³ to R ¹⁰ are, independently of one another, hydrogen or a Ci-Cio, particularly preferably Cr to C ₄ , very particularly preferably Cr to C ₂ carbon-containing radical, or two adjacent radicals R ³ to R ¹⁰ together form a cyclic ring system with the atoms connecting them, which in addition to carbon atoms can contain a heteroatom selected from the group consisting of the elements N and O in the ring system.

1 to 4, preferably 2 or 3 of the radicals R ³ to R ^{6 are} preferably hydrogen and 0 to 3, preferably 1 or 2 of the radicals R to R are a radical other than hydrogen, particularly preferably a branched or unbranched Cr to C ₁₀ -, preferably Cr to C alkyl radical. 0 to 3, preferably 1 or 2 of the radicals R ³ to R ⁶ are very particularly preferably methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl or t-butyl radicals. The same applies to the radicals R ⁷ to R ¹⁰ .

At least one of the radicals R ³ to R ⁶ and at least one of the radicals R ⁷ to R ^{10 is} very particularly preferably a radical other than hydrogen, preferably a branched or unbranched Cr to C ₁₀ -, particularly preferably Cr to C ₄ -alkyl radical particularly preferably a methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl or t-butyl radical. In a further very particularly preferred embodiment, R ³ , R ⁵ , R ⁷ and R ^{9 are} a radical other than hydrogen, preferably a branched or unbranched Cr to C ₁₀ -, particularly preferably Cr to C ₄ -alkyl radical, very particularly preferably a methyl -, ethyl, n-propyl, i-propyl, n-butyl, i-butyl or t-butyl.

R ¹¹ is preferably hydrogen or a CrC ₁₀ -, particularly preferably Cr to C -, very particularly preferably Cr to C ₂ -carbon-containing radical. R ¹¹ is particularly preferably hydrogen or a methyl, ethyl, n-propyl, i- Propyl, n-butyl or t-butyl.

In the ligand system of the formula ID, D 'oxygen, Y, Y' sulfur, and q are very particularly preferably an integer from 1 to 5, preferably 1 to 3. In a further preferred embodiment, the radicals R ³ and R ⁷ , R ⁴ and R ⁸ , R ⁵ and R ⁹ , R ⁶ and R ¹⁰ each have the same radical, R ³ and R ⁷ , and R ⁵ and R ⁹ each represents the same radicals other than hydrogen, preferably branched or unbranched Cr to C ₁₀ -, particularly preferably Cr to C ₄ -alkyl radicals, very particularly preferably methyl, ethyl, n-propyl, i-propyl, n- Butyl, i-butyl or t-butyl radicals on and R ⁴ and R ⁸ , and R ⁶ and R ¹⁰ are hydrogen.

The preparation of the ligand system according to the invention can be carried out by all methods known to the person skilled in the art.

In a preferred embodiment, a compound of the formula (F) is first

prepared in which the symbols have the meanings given above for formula I. Methods for the preparation of compounds of the formula F are known to the person skilled in the art. The further procedure depends on whether symmetrical or asymmetrical ligand systems are to be produced.

In the preparation of symmetrical ligand systems, the compounds of the formula F are reacted with a base, for example NaOH, generally in alcoholic solution, and then a reaction with a bisfunctional compound of the formula X ¹ - (CR ¹ R ² ) _q -X ² , in which q and R ¹ and R ^{2 have} the meaning given for the ligand system of the formula I and X ¹ and X ^{2 are} in general independently of one another in each case a halogen radical, preferably Br. In a very particularly preferred embodiment, q is 2 or 3 and X ¹ - (CR ^^ _q -X ² is 1,2-dibromoethane or 1,3-dibrornopropane. The compound of the formula P is generally approximately twice molar amount to the compound X ¹ - (CR ¹ R ² ) ₍₁ -X ²⁾ . In the symmetrical ligand systems of the formula I according to the invention, the symbols R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , D 'and Y' have the same meaning as the corresponding symbols R ³ , R ⁴ , R ⁵ , R ⁶ , D and Y in formula 1 '.

It is also possible to use the method described above to produce asymmetrical ligand systems which have differently substituted aromatic radicals, i.e. the compounds of the formula P and a compound of the formula Ia 'are reacted,

wherein at least one of the radicals R ⁷ to R ¹⁰ differs from the radicals R ³ to R ^{6 of} the compound of the formula P, with a bisfunctional compound of the formula X ¹ - (CR R) _q -X. The radicals R to R have the meanings already mentioned in formula I. The compounds of the formulas P and Ia 'are generally used in approximately equimolar amounts.

In a preferred embodiment, asymmetrically bridged ligand systems of the formula I are also prepared by reacting a compound of the formula P with a compound of the formula I "

wherein the symbols have the meanings given in formula I and X ³ is generally halogen, preferably Br. The compounds of the formulas P and I "are generally used in approximately equimolar amounts. Working up is carried out by methods known to the person skilled in the art.

The ligand system of formula I according to the invention is suitable for the production of transition metal compounds.

The present application therefore furthermore relates to a transition metal compound of the formula (11)

wherein

M is an element of the 3rd, 4th, 5th, 6, 7th, 8th, 9th or 10th group of the

Periodic table of the elements or an element of the lanthanides is

X, X 'can be the same or different and is an organic or inorganic anionic ligand, ol, o2 may be the same or different and are 0 or 1, where ol + o2 + 2 corresponds to the oxidation number of M,

D, D 'can be the same or different and represents oxygen, sulfur, selenium, tellurium, an NR ¹¹ group or PR ¹ group,

p is 0 or 1,

R ¹ , R ^{2 can be the} same or different and are hydrogen or a Cr C ₄₀ - carbon-containing radical, or two radicals R and R together with the carbon atom connecting them or, if q> 1, two radicals R ¹ together with the carbon atoms connecting them form a cyclic or polycyclic ring system which, in addition to carbon atoms, may contain one or more identical or different heteroatoms selected from the group consisting of the elements N, O, P, S and Si in the ring system,

q is an integer from 1 to 10,

R ³ to R ^{10 may be the} same or different and are hydrogen or a CrC ₀ - carbon-containing radical, or two adjacent radicals R ³ to R ¹⁰ together with the atoms connecting them form a cyclic or polycyclic ring system which contains one or more carbon atoms in the ring system may contain several identical or different heteroatoms selected from the group consisting of the elements N, O, S and Si,

R ^{11 is} hydrogen or a CrC ₄ o-carbon-containing radical. After activation with an activator (cocatalyst), these transition metal compounds are very active in the polymerization of unsaturated compounds.

M is preferably an element of the 4th, 5th, 8th, 9th or 10th group of the Periodic Table of the Elements, very particularly preferably an element of the 4th group of the Periodic Table of the Elements, in particular Ti, Zr or Hf.

X, X 'are preferably each independently an organic ligand selected from the group consisting of CrC _t o-alkyl, C ₂ -C ₁₀ alkenyl, C ₆ -C ₁₄ -aryl, arylalkyl having from 1 to 10 carbon atoms in the alkyl radical and 6 to 14 carbon atoms in the aryl radical, alkylaryl with 1 to 10 carbon atoms in the alkyl radical and 6 to 14 carbon atoms in the aryl radical, NR'R "- and OR '", where R' and R "are C to C ₁₀ -, preferably C to C ₃ Alkyl radicals, particularly preferably Cr to C ₂ alkyl radicals and R '"is a C to C ₁₀ , preferably Cr to C ₃ alkyl radical, particularly preferably an i-propyl radical, or a halide radical, preferably selected from chloride and bromide. X and X 'are particularly preferably independently of one another benzyl, i-propoxy or chloride groups. X is very particularly preferably X '.

ol, o2 are independently 0 or 1, where ol + o2 + 2 corresponds to the oxidation number of M. If M is a transition metal from Group 4 of the Periodic Table of the Elements and has the oxidation state IV, preferably Ti (IV), Zr (IV), Hf (IV), then both ol and o2 are 1.

Preferred embodiments of groups D, D ', Y, Y', p, R ¹ , R ² , q and R ³ to R ¹⁰ and R ^u as well as preferred embodiments of combinations of these groups have already been mentioned above with regard to the ligand systems and are also related preferred transition forms of the transition metal compounds according to the invention.

Is particularly preferred in the transition metal compounds of formula II according to the invention

M is an element of the 4th group of the Periodic Table of the Elements, X, X 'independently of one another are a halide, CrCio-alkyl, C ₂ -C ₁ o-alkenyl, C ₆ -C ₁ aryl, alkylaryl or arylalkyl with 1 to 10 carbon atoms in the alkyl radical and 6 to 14 carbon atoms in the aryl radical, NR' R "- and OR '", wherein R' and R "are Crbis Cio, preferably Cr to C ₃ alkyl, particularly preferably C _\ - to C ₂ alkyl and R""is a Crbis C ₁₀ -, preferably Cr bis C ₃ alkyl radical, particularly preferably an i-propyl are particularly preferred X and X 'are independently i-propyl or halide radicals, preferably selected from chloride and bromide,

ol, o2 1,

D, D 'oxygen,

Y, Y 'sulfur,

q is an integer from 1 to 5, preferably 1 to 3.

The other variables have the meanings given above.

It is very particularly preferred in the transition metal compounds according to the invention that p is 1, D is D ', Y is Y' and X is X '.

The transition metal compounds of the formula II according to the invention are particularly preferably C2-symmetrical. Such C2-symmetrical transition metal compounds are suitable for the production of highly isotactic polystyrene or copolymers containing highly isotactic polystyrene.

The transition metal compounds according to the invention can be prepared from the ligand systems according to the invention by customary methods known to the person skilled in the art

Procedure. In general, the transition metal compound is through Implementation of a ligand system according to the invention or a dianion prepared therefrom with a transition metal compound.

The transition metal compounds of the formula II according to the invention are usually prepared by reacting the corresponding compounds of the general formula I with transition metal salts of metals from groups 3, 4, 5, 6, 7, 8, 9 or 10 of the periodic table of the elements or an element of the lanthanides. Preferred metals are mentioned above.

In a preferred embodiment, a suitable ligand system of the general formula I is in an organic solvent, for example toluene, tetrahydrofuran (THF) or methylene chloride, with a corresponding metal salt, for example titanium tetraisopropoxide, titanium, zirconium or hafnium tetrachloride, titanium, zirconium or hafnium tetrabenzyl , combined in the same organic solvent at temperatures of generally -90 ° C to + 35 ° C, preferably -80 ° C to 30 ° C. The molar ratio of ligand to metal salt is generally 1.5: 1 to 1: 1.5, preferably 1.2: 1 to 1: 1.2, particularly preferably approximately 1: 1. The reaction mixture is then generally at temperatures from 20 to 50 ° C, preferably from 20 to 40 ° C, particularly preferably at room temperature for generally 15 minutes to 16 hours, preferably 0.5 hours to 6 hours, particularly preferably 0.5 Stirred up to 2 hours. Working up is carried out in a conventional manner, for example by removing the solvent in vacuo, washing the residue with a solvent in which the residue (product) is largely insoluble, for example with pentane, hexane or diethyl ether, optionally digesting in a non-polar solvent, for example hexane 'Filtering, washing and drying'. In an alternative work-up variant, the transition metal compound can be precipitated out of the reaction mixture by concentration in vacuo and / or addition of a non-polar solvent, for example hexane and / or cooling to, for example, from -40 ° C. to -10 ° C. It is then filtered off, washed and dried by methods known to those skilled in the art. It is also possible to convert the ligand system of the formula I according to the invention first into the corresponding dianion by reaction with a strong base, for example n-butyllithium, and to convert this dianion with the metal salts mentioned above. The process conditions are known to the person skilled in the art.

The transition metal compounds of formula II according to the invention are easily accessible and - together with a cocatalyst - are suitable as catalysts for the polymerization of unsaturated compounds.

Another object of the present application is therefore a catalyst system for the polymerization of unsaturated compounds containing at least one transition metal compound of the formula II and at least one cocatalyst.

Suitable preferred transition metal compounds have already been mentioned above.

Strong, neutral Lewis acids, ionic compounds with Lewis acid cations and ionic compounds with Bronsted acids are particularly suitable as cations as cocatalysts (activators).

Compounds of the general formula (III) are preferred as strong, neutral Lewis acids,

in which the symbols have the following meaning

M 'an element of III. Main group of the periodic table of the elements, preferably B, Al or Ga, particularly preferably B, Q ¹ , Q ² , Q ³ independently of one another hydrogen, Cr to Cio-alkyl, C ₆ - to C ₁₅ -aryl, alkylaryl, arylalkyl, haloalkyl or Halogenaryl with 1 to 10 each

Carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the Aryl radical or fluoride, chloride, bro id or iodide, preferably for haloaryls, particularly preferably for pentafluorophenyl.

Compounds of the general formula (TU) in which Q ¹ , Q ² , Q ^{3 are} identical are particularly preferred, preferably tris (pentafluorophenyl) borane.

Another neutral Lewis acid preferably used as cocatalyst (activator) is “R ^π AlO” (alkylaluminoxane), in which R ^{11 is} a C to C ₂₅ -alkyl, preferably a Cr to C ₄ -alkyl radical, particularly preferably a methyl radical (methylaluminoxane) ,

Suitable ionic compounds with Lewis acid cations are compounds of the general formula (IV)

[(Y 7-a ^a + -N) iT-p _! rTp ₂ . rp _η +

• T _z ] ^c (IV)

in which the symbols have the following meanings

Y is an element of I. to VI. Main group or the I. to VIII. Subgroup of the periodic table of the elements,

Ti to T _z simply negatively charged radicals such as Cr to C ₂₈ alkyl, C ₆ to C ₅ aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl, each with 6 to 20

Carbon atoms in the aryl and 1 to 28 carbon atoms in the alkyl radical, Cr to Cio-cycloalkyl, which may optionally be substituted by Cr to C ₁₀ alkyl groups, halide, Cr to C ₂₈ alkoxy, C ₆ to C ₁₅ aryloxy, silyl - or mercaptyl groups, a integers from 1 to 6, z integers from 0 to 5, d difference from az, but d is greater than or equal to 1.

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 l, l'-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 the cation and preferably also non-coordinating counterions are also mentioned in WO 91/09882, the preferred cation is N, N-dimethylanilinium.

Methylaluminoxane, aluminum alkyl compounds and aryl borates such as tetrakis (pentafluorophenyl) borate are particularly preferably used as cocatalysts.

The amount of cocatalyst (activator) is preferably 0.1 to 10 equivalents, based on the transition metal compound II. For alkylalurninoxanes, in particular memylaluminoxane, the amount of cocatalyst (activator) is generally 50 to 1000 equivalents, preferably 100 to 500 equivalents, particularly preferably 100 to 300 equivalents, based on the transition metal compound II.

The catalyst systems according to the invention can be used in the form of unsupported catalysts or supported catalysts, depending on the polymerization conditions.

When the catalyst systems according to the invention are used, they are homogeneously dissolved in the solution during solution polymerization. The catalyst systems according to the invention can be prepared “in situ” and used directly in the polymerization without prior isolation. The catalyst systems according to the invention are generally prepared by adding the transition metal compound according to the invention to a solution of the cocatalyst and the unsaturated compound to be polymerized or optionally a mixture of two or more unsaturated organic compounds in an organic solvent, other addition orders are also possible. Another object of the present application is a catalyst system according to the invention which additionally contains a support.

Finely divided solids are preferably used as carrier materials, the particle diameters of which are generally in the range from 1 to 200 μm, preferably from 30 to 70 μm.

Suitable carrier materials are, for example, silica gels, preferably those of the formula Si0 ₂ ^• a Al ₂ O _3; wherein a is a number in the range from 0 to 2, preferably from 0 to 0.5; it is therefore alumosilicates or silicon dioxide. Such products are commercially available, for example Silica Gel 332 from Grace or ES 70x from Crosfield.

These carrier materials can be subjected to a thermal or chemical treatment or calcined to remove adsorbed water, a treatment preferably being carried out at 80 to 200 ° C., particularly preferably at 100 to 150 ° C.

Other inorganic compounds such as Al ₂ O ₃ or MgCl ₂ or mixtures containing these compounds can also be used as carrier materials.

The catalysts can also be prepared “in situ” in the presence of support material. However, it is also possible to prepare and isolate the catalyst system according to the invention comprising a support. The catalyst system can then be used for the polymerization of unsaturated compounds.

The catalyst systems according to the invention, both with and without a carrier, are prepared by processes known to those skilled in the art.

The catalyst systems according to the invention are suitable for use in the polymerization of unsaturated compounds. Another object of the present application is a process for the preparation of polymers by polymerization or copolymerization of at least one unsaturated compound in the presence of a catalyst system according to the invention.

Suitable unsaturated compounds are, for example, vinyl aromatic monomers, ethylene, C ₃ - to C ₂₀ -, preferably C ₃ - to C ₈ -monoolefins and cycloolefins. Preferred C ₃ - to C ₈ - mono-olefins are propylene, 1-butene, 1-hexene and 1-octene. Preferred cycloolefins are norbornene, norbonadiene and cyclopentene.

Suitable vinylaromatic monomers are, for example, styrene and styrene e, preferably styrene, α-methylstyrene or p-methylstyrene, substituted one to three times with CrC ₄ alkyl or halogen in the α position and / or at the core. A particularly preferred vinyl aromatic monomer is styrene.

The unsaturated compounds mentioned can be used to prepare homopolymers or copolymers composed of at least two unsaturated compounds. The process according to the invention gives polymers, in particular polymers and copolymers, composed of vinylaromatic monomers, in particular styrene, with a narrow molecular weight distribution M _w / M _n of generally <3, preferably <2.5, particularly preferably <2.

Vinyl aromatic compounds, preferably styrene, α-methylstyrene, p-methylstyrene, ethylene or C ₃ - to C ₈ -monoolefins such as propylene, 1-butene, 1-hexene and 1-octene are preferably used as unsaturated compounds in the homopolymerization. At least one vinylaromatic compound is preferably used in the copolymerization, styrene and ethylene, styrene and propylene and styrene and butylene are particularly preferably used. The present application also relates to a process in which at least one vinylaromatic compound, preferably styrene, α-methylstyrene or p-methylstyrene, particularly preferably styrene, is used as the unsaturated compound.

In a preferred embodiment, styrene is polymerized or copolymerized in the process according to the invention. It has surprisingly been found that when C2-symmetrical transition metal compounds of the formula II are used, highly isotactic polystyrene or copolymers which contain highly isotactic polystyrene units are obtained in the homo- or copolymerization of styrene.

According to the present application, highly isotactic polystyrene or highly isotactic polystyrene units are understood to be polystyrene which is composed of at least 80%, preferably at least 85%, particularly preferably at least 90% of m-diads. The proportion of m-diads is determined using ^ -N E.

Another object of the present application is thus the use of a transition metal compound according to the invention or a catalyst system according to the invention for the production of isotactic polystyrene. Preferred transition metal compounds and catalyst systems have already been mentioned above.

The catalyst system according to the invention is used as the catalyst system in the process according to the invention. Preferred catalyst systems are mentioned above. In the production of highly isotactic polystyrene or copolymers containing highly isotactic polystyrene units, the use of C2-symmetrical transition metal compounds in the catalyst system according to the invention is preferred. It is also possible to use the catalyst system according to the invention not alone, but in conjunction with other catalyst systems of the same type or with other polymerization catalysts (such as Phillips, Ziegler, metallocene catalysts).

Depending on the reaction conditions and the unsaturated compounds (monomers) used, it is possible to obtain homopolymers, random copolymers or block copolymers with the process according to the invention. The polymerization is carried out under generally customary conditions in solution, for example as high-pressure polymerization in a high-pressure reactor or high-pressure autoclave, in suspension or in the gas phase (for example GPWS polymerization process). Polymerization in solution is preferred. The corresponding polymerization processes can be carried out as a batch process, semi-continuously or continuously, the procedures being known from the prior art.

Aprotic organic solvents are particularly suitable as solvents. The catalyst system, the monomer (unsaturated compound) and the polymer can be soluble or insoluble in these solvents, but the solvents should not participate in the polymerization. Suitable solvents are alkanes, cycloalkanes, selected halogenated hydrocarbons and aromatic hydrocarbons. Preferred solvents are hexane, toluene and benzene, toluene is particularly preferred.

The following examples further illustrate the invention.

Examples

General

The preparation and handling of the organometallic compounds and their use as a catalyst component were carried out with the exclusion of air and moisture under an argon protective gas (ScHenk-Teclrnik or Glove-Box). All required solvents were flushed with argon before use and absoluteized using a molecular sieve. 2-Bromomethyl-6-tert-butyl-4-methylphenol was prepared from 2-tert-butyl-4-methylphenol by hydroxymethylation (US 2,792,428) and subsequent bromination with PBr ₃ according to known methods of organic chemistry.

polymer analysis The polymers were examined by NMR on a Bruker ARX 300, with C2D2CI ₄ serving as the solvent. DSC measurements to determine T _g and T _m were carried out on a Seiko DSC 6200 at a heating rate of lOK / min. Wide-angle X-ray scattering (WAXS) on iPS was carried out using a Siemens D500 powder diffractometer equipped with a temperature-controlled sample holder. GPC measurements were carried out in 1,2,4-trichlorobenzene (TCB) at 140 ° C with TR detection and PS calibration.

Manufacture of substituted 2-hydroxybenzenethiols

Example 1 3-tert-Butyl-5-methyl-2-hydroxybenzenethiol (1)

.a) Synthesis of 2,2'-trithiobis (6-tert-butyl-4-methylphenol) (1 a) To a solution of 164 g (1 mol) of 2-tert-butyl-4-methylphenol and 1.98 g (10 mmol)

Titanium (rV) chloride in 700 ml of toluene was slowly added to 67.52 g (0.5 mol) at 5 ° C.

Sulfur monochloride added dropwise. After the "start" of the reaction, the mixture was cooled, with further dropwise addition, to -5 to -10 ° C. After the HCl development had ended, the mixture was stirred at room temperature for two more days. The reaction mixture was then washed twice with 500 ml of semi-concentrated HCl, then each time washed once with saturated NaHCO ₃ solution and with water and the organic phase was washed over

Dried sodium sulfate and the solvent removed in vacuo. The residue was recrystallized twice from acetonitrile and 76.1 g (36%) of a red-yellow powder were obtained, which was not further purified since it contained both 2,2'-trithiobis (6-tert-butyl-4-methylphenol) as well as 2,2'-dithiobis (6-tert-butyl-4-methylphenol).

b) Synthesis of 3-te7 "t-butyl-5-methyl-2-hydroxybenzenethiol (1) to a mixture of 80 g of 2,2'-trithiobis (6-tert-butyl-4-methylphenol (from Example 1 a) , 4 1 3 N HCl, 1000 ml of toluene and 500 ml of ethanol, 157 g of zinc powder were added in small portions over two days After the organic phase had been separated off, it was washed with water and dried over Na ₂ SO ₄ Solvent removed in vacuo. The residue was distilled in vacuo and 51 g (72%) of 3-tert-butyl-5-methyl-2-hydroxybenzenefiol were obtained as a colorless solid (at 0.03 torr, 58-59 ° C). EI-MS: m / z (%) = 196 (51) [M ^{1 "} ], 181 (100) [M ⁺ -CH ₃ ], 153 (24) [M ⁺ -C ₃ H ₇ ]

Example 2 3-te7 "t-butyl-5-methoxy-2-hydroxybenzenethiol (2)

a) Synthesis of 2,2'-dithiobis (6-te7't-butyl-4-methoxyphenol) (2a)

Analogously to the synthesis in Example 1 a), starting from 6-tert-butyl-4-methoxyphenol, the compound 2,2'-dithiobis (6-tert-butyl-4-methoxyphenol) was introduced as an orange powder in

Obtained 54% yield.

1H NMR (C ₆ D ₆ ): δ = 1.39 (s, 18 H, C (CH ₃ ) ₃ ), 3.22 (s, 6 H, CH ₃ ), 6.39 (s, 2 H) , OH), 6.46

(d, ⁴ J _H , H = 2.9 Hz, 2 H, meta-CH), 7.09 (d, ⁴ JH, _H = 2.9 Hz, 2 H, meta-CH)

¹³ C NMR (C ₆ D ₆ ): δ = 29 (C (CH ₃ ) ₃ ), 35.1 (C (CH ₃ ) ₃ ), 54.7 (CH ₃ ), 115.7 (meta-Q , 119.3 (meta-Q, 120.1 (ortho-C (S)), 137.9 (ortho-C (t-Bu)), 150 (para-Q, 152.5 (ipso-Q

EI-MS: M / z (%) = 422 (38) [M * ^" ], 390 (5) [M ⁺ -CH ₃ OH], 211 (100) [C _π Hι ₅ 0 ₂ S ⁺ ] ₅ 178 (41)

[211-SH], 91 (22) [C ₇ H ₈ ⁺ ]

b) Synthesis of 3-te7't-butyl-5-methoxy-2-hydroxybenzenethiol (2) Analogously to the synthesis in Example 1-b), starting from 2,2'-dithiobis (6-te7-t-butyl-4 - methoxyphenol) (2a) the thiol 3-tert-butyl-5-memoxy-2-hydroxybenzenethiol (2). (2) was obtained after distillation (71 ° C at 0.03 torr) in 79% yield as a colorless crystal mass. EI-MS: M / z (%) = 212 (79) [M ⁺ ], 197 (100) [M ⁺ -CH ₃ ], 178 (9) [^ S], 169 (31) [M ⁺ - C ₃ H ₇ ], 91 (11) [C ₇ H ₈ ⁺ ]

Example 3 3,5-di-tert-butyl-2-hydroxybenzenethiol (3)

Analogously to the synthesis in Example 1 a) and 1 b), starting from 2,4-di-te7-t.-butylphenol, the intermediate 2,2'-dithiobis (4,6-di-te7.-Butyl- phenol) the thiol 3,5-di-tert-butyl-2-hydroxybenzenethiol (3). Production of bisphenolato ligands

Example A1, 4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methylphenol) (A)

46 g (0.234 mol) of 3-tert-butyl-5-me-2-hy-oxybenz; olthiol (1) were dissolved in 500 ml of methanol. 9.39 g (0.234 mol) of sodium hydroxide were added to this solution. The suspension was heated to 50-60 ° C until the sodium hydroxide had completely dissolved. 22.06 g (10.32 ml / 0.117 mol) of 1,2-dibromoethane were added dropwise at the same temperature and the reaction mixture was refluxed for one hour. Precipitated product, which impeded the stirring, was dissolved by adding a further 150 ml of methanol. After the suspension had cooled, the solvent was removed in vacuo, the residue was taken up in hot toluene and the insoluble sodium bromide was filtered from the supernatant solution. The solvent was removed in vacuo and 46.2 g (94%) of 1,4-dithiabutanediyl-2,2-bis (6-tert-butyl-4-methylphenol) (A) were obtained as colorless flakes which, without further purification, were obtained in the following syntheses were used.

EI-MS: m / z (%) = 418 (23) [M ⁺ ], 223 (59) [Cι ₃ H ₁₉ OS ⁺ ], 195 (100) [C _π H ₁₅ OS ⁺ ], 57 (3) [C ₄ H ₉ ⁺ ]

Example B 1, 4-dithiabutanediyl-2,2'-bis (6-te7 * t-butyl-4-methoxvphenoι) (B)

Analogously to Example A, starting from 3-te7-butyl-5-methoxy-2-hydroxybenzenolfiol (2), the bisphenolate ligand l, 4-dithiabutanediyl-2,2-bis (6-te7-t-butyl-4-methoxyphenol) ( B) obtained as a light beige powder in 61% yield.

EI-MS: M / z (%) = 450 (26) [M ⁺ ], 239 (27) [M ⁺ -C _n H ₁₅ O ₂ S], 211 (100) [C _π H ₁₅ O ₂ S ⁺ ], 178 (27)

Example C1, 4-dithiabutanediyl-2,2'-bis (4,6-di-tert-butylphenol) (C) Analogously to Example A, a solution of 1.5 g (6.3 mmol) of 3,5-di-tert-butyl-2-hydroxybenzenethiol (3) from Example (3) and 0.25 g (6.3 mmol) was obtained ) NaOH in 25 ml of methanol at 0 ° C with 0.58 g (3.1 mmol) of 1,2-dibromoethane. After working up as described in Example A and recrystallization from acetone / acetonitrile, 0.84 g (55%) of the ligand (C) was obtained in the form of colorless crystals.

EI-MS: M / z (%) = 502 (45, M ⁺ ), 265 (100, C ₁₆ H ₂₅ OS ⁺ ), 237 (99, C ₁₄ H ₂₂ OS ⁺ ), 181 (33, C ₁₀ H ₁₄ OS ⁺ ), 56 (76, C ₄ H ₈ ⁺ ).

Example D 1,5-Dithiapentanediyl-2,2'-bis (4,6-di-tert-butylphenol) (D)

Analogously to Example C, the bisphenolate (D) was prepared by reacting 3,5-di-tert-butyl-2-hydroxybenzenethiol (3) from Example (3) with 1,3-dibromopropane in 28% yield. EI-MS: M / z (rel. Int.%) = 516 (100, *), 460 (11, M ^ C ₄ H ₈ ), 279 (23, C ₁₇ H ₂₇ OS ₂ ⁺ ), 279 (31 , C ₁₇ H ₂₇ OS ⁺ ), 56 (30, C ₄ H ₈ ⁺ ).

Example E 2- (3'-tert-Butyl-2'-hyάroxy-5'-methylbenzylthio) -6-tert-butyl-4-methylphenol (E)

KHCO (1.65 g, 16.4 mmol) was added to the solution of 6-tert-butyl-4-methyl-2-mercaptophenol (3.23 g, 16.4 mmol in 15 mL DMF). The mixture was stirred for 30 min Pure 2-bromomethyl-6-te7-t-butyl-4-methylphenol (1.46 g, 5.68 mmol) was slowly added dropwise to the resulting clear pale yellow solution, during which time the solution decolorized and one After stirring for about 14 hours at room temperature, 20 ml of water were added, the mixture was then extracted three times with 40 ml of diethyl ether, the combined organic phases were washed with water and NaCl _aq and dried with MgSO ₄ and the solvent was removed under reduced pressure and the product was recrystallized from petroleum ether. Yield: 5.7 g (15.3 mmol, 93%). EI-MS (70 eV): m / z = 372 (16%, M ⁺ ), 177 (100%, [ HOC ₆ H ₂ (C ₄ H ₉ ) (CH ₃ ) CH ₂ ]). Example F 4,6-di-tert-butyl-2- (3'-tert-butyl-2 '-hydroxy-5' -methylbenzylthio) phenol (F)

4,6-Di-te7-t-butyl-2-mercaptophenol (1.36 g, 5.70 mmol), 5 ml of dimethylformamide and KHCO ₃ (571 mg, 5.70 mmol) were initially charged and intensive for 30 min at room temperature touched. The solution of 2-bromomethyl-6-tert-butyl-4-methylphenol (1.46 g, 5.68 mmol) in 5 ml of dimethylformamide was added. After stirring for about 15 hours at room temperature, 50 ml of diethyl ether were added. The solution was washed with H ₂ O and saturated NaCl _aq and dried with MgSO ₄ . The solvent was removed and the crude product was purified by column chromatography (ethyl acetate / hexane, 3:97). Yield: 1.58 g (3.81 mmol, 67%).

EI-MS (70 eV): m / z = 414 (14%, M ^{1 "} ), 177 (100%, [HOC ₆ H ₂ (C ₄ H ₉ ) (CH ₃ ) CH ₂ ] ⁺ ).

Example G 2- (3'-te7-t-Butyl-2'-hydroxy-α-methylbenzylthio) -6-te7't-butyl-4-methylphenol (G)

KHCO ₃ (1.65 g, 16.4 mmol) was added to dissolve the 6-te7-t-butyl-4-methyl-2-mercaptophenol (3.51 g, 13.6 mmol) in 14 mL DMF. After stirring intensively for 30 min, pure 2- (l'-bromoethyl) -6-tert-butylphenol (2.68 g, 13.6 mmol) was slowly added dropwise at room temperature. The discoloration of the solution and a slight clouding of the reaction mixture were observed. After stirring for about 14 hours at room temperature, 20 ml of water were added. The mixture was then extracted three times with 40 ml of diethyl ether, the combined organic phases were washed with water and NaCl _aq and dried with MgSO ₄ . After removing the solvent, the product was obtained as 1: 1 mixture of isomers in the form of a colorless oil. Yield: 4.71 g (12.6 mmol, 93%). The isomers were separated by column chromatography (hexane / ethyl acetate 97: 3). EI-MS (70 eV): m / z = 372 (3%, M ^"1" ), 177 (100%, [HOC ₆ H ₃ (C ₄ H ₉ ) (CH ₃ ) CH] ⁺ ). Found C: 74.35; H: 8.43; S: 8.54.

Synthesis of transition metal compounds

Example I Di (isopropoxy) {1,4-difhiabutanediyl-2,2'-bis (6-tert-butyl-4-methylphenoxy)} titanium (I)

724 mg (2.55 mmol / 755 μl) titanium tetraisopropoxide were dissolved in 10 ml toluene. This solution was added at -25 ° C. to a suspension of 1.065 g (2.55 mmol) of the bisphenolate ligand (A) from Example A in 40 ml of toluene. The solution immediately turned lemon yellow. The mixture was then stirred for a further 2 hours at room temperature, then the solvent was removed in vacuo and the residue was taken up in 7 ml of hexane. After filtering the solution, it was cooled to -30 ° C., whereby a yellow solid precipitated out. The supernatant solution was filtered off, residual solvent removed in vacuo and 1.17 g (79%) (I) was obtained as a lemon yellow powder.

EI-MS: M / z (%) = 582 (100) [M ⁺ ], 523 (36) [M ⁺ -OC ₃ H ₇ ], 57 (24) [C ₄ H ₉ ⁺ ]

Example II dichloro {1,4-dithiabutanediyl-2,2'-bis (6-te7-t-butyl-4-methylphenoxy)} titanium (II)

1 g (2.4 mmol) of ligand (A) were suspended in 20 ml of toluene and cooled to -70 ° C. A solution of 455 mg (2.4 mmol / 263 μl) titanium tetrachloride in a little toluene was added dropwise to this suspension. After 15 min. Stirring at this temperature was warmed to room temperature and stirred for an additional two hours. The mixture was then cooled to -30 ° C. and the precipitated burgundy powder was isolated by filtration. 1.04 g (81%) (II) were obtained. Dark red, single crystal needles were obtained by slowly evaporating benzene in the glove box. EI-MS: M / z (%) = 535 (100) [M ⁺ ], 499 (4) [M ^ -Cl], 483 (89), 419 (30) [LigandH ⁺ ], 57 (20) [ (CH ₃ ) C ⁺ ]

Example III Dicmoro {l, 4-dithiabutanediyl-2,2'-bis (6-te7't-butyl-4-meylphenoxy)} hafnium (III)

1 g (2.4 mmol) of ligand (Ä) were suspended in 20 ml of toluene and cooled to -20 ° C. A second suspension of 767 mg (2.4 mmol) of hafhium tetrachloride in 20 ml of toluene was added to this suspension. After 15 min. Stirring at this temperature was warmed to room temperature and stirred for a further two hours, after about 10 minutes the solution becoming yellow and almost clear. The solvent was then filtered and removed in vacuo. Compound (III) was obtained as a light yellow powder in 98% yield. Amber crystals of (III) for X-ray structure analysis were obtained by slowly evaporating the solvent from benzene solution.

EI-MS: M / z (%) = 666 (100) [M ⁺ ], 651 (4) [M ^ CHs], 615 (48) [M'-CHsCl], 146 (22) [C _U H ₁₄ ⁺ ], 91 (64) [C ₇ H ₈ ⁺ ]

Example IV Di (isoproxy) {1,4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methoxyphenoxy)} titanium (TV)

A solution of 631 mg (2.16 mmol) titanium tetraisopropoxide in 10 ml toluene was -

25 ° C. to a solution of 970 mg (2.16 mmol) of the bisphenolate ligand (B) from Example B in 40 ml of toluene. The reaction solution immediately turned orange. The solution was

Stirred for 15 minutes at -25 ° C and then for 2 hours at room temperature.

The solution was then concentrated to a few ml and the product fell overnight -

30 ° C. The supernatant solution was filtered off and 924 mg (71%) (IV) were obtained as orange microcrystalline needles. EI-MS: M z (%) = 614 (22) [M ⁺ ], 555 (4)

238 (50) [Cι ₃ H ₁₉ O ₂ S ⁺ ], 91 (100)

[C ₇ H ₈ ⁺ ] Example V Dichloro {1,4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methoxyphenoxy)} titanium (V)

Analogously to Example II, 2.339 g (5.2 mmol) of the bisphenolate ligand (B) were reacted with 987 mg (5.2 mmol) of titanium tetrachloride. 2.94 g (88%) (V) were obtained in the form of a dark red powder.

EI-MS: M / z (%) = 566 (100) [M], 538 (5) [M ⁺ -CO], 515 (43) [M -CH ₃ CTJ, 238 (72) [C ₁₃ H ₁₈ O ₂ S ⁺ ], 57 (53) [(CH ₃ ) C ⁺ ]

Example VI DicMoro {1,4-dithiabutanediyl-2,2'-bis (6-te7't-butyl-4-methoxyphenoxy)} zirconium (VI)

A solution of 1.04 g (2.31 mmol) of the bisphenolate ligand (B) in 35 ml of toluene was added dropwise to a -30 ° C. cold suspension of 538 mg (2.31 mmol) of ZrCl ₄ in 10 ml of toluene, 10 minutes at this temperature and 2 more Stirred for hours at room temperature. The reaction mixture was filtered and frozen at -30 ° C overnight. After renewed filtration, 1.38 g (98%) (VI) were obtained in the form of a pale yellow solid. EI-MS: M / z (%) = 610 (100) [M ⁴ , 582 (10) [M ⁺ -CO], 559 (24) [M ⁺ -CH ₃ C1], 239 (5)

[C ₁₃ H ₁₈ Ö ₂ S ⁺ ], 57 (20) [(CH ₃ ) C ⁺ ]

Example VII dichloro {1,4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methoxyphenoxy)} hafhium (VII)

Analogously to Example VI, 1.004 g (2.23 mmol) of the bisphenolate ligand (B) was also added

715 mg (2.23 mmol) of hamium tetrachloride reacted. 1.444 g (94%) (VII) were added

Obtained form of an orange-yellow solid.

EI-MS: M / z (%) = 698 (100) [M *], 670 (130) [M'-CO], 647 (25) [M ^ CHsCl], 619 (28),

179 (4) [CπH ₁₅ O ₂ ⁺ ], 57 (24) [(CH ₃ ) C ⁺ ] Example VHI Dibenzyl {1, 4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methylphenoxy)} zirconium (VIII)

A suspension of 650 mg (1.556 mmol) of the bisphenolate ligand (A) in 10 ml of toluene was cooled to -80 ° C. A solution of 707.5 mg (1.556 mmol) of zirconium tetrabenzyl in 15 ml of toluene was added dropwise. The reaction mixture was stirred at this temperature for 15 minutes and then at room temperature for 1.5 hours. The concentrated solution was kept at -30 ° C. overnight and then the precipitated solid was filtered off. 878 mg (82%) (VIII) were obtained in the form of a light yellow powder.

C ₃₈ H ₄₆ θ ₂ S ₂ Zr (689) calcd: C: 66.13 H: 6.72 S: 9.29 found: C: 64.37 H: 6.95 S: 9.33

Example LX Dibenzyl {1,4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methylphenoxy)} hafnium (LX)

Analogously to Example VIII, 650 mg (1.556 mmol) of the bisphenolate ligand (A) and the equimolar amount of hafnium tetrabenzyl gave the compound (IX) in a yield of 1,026 g (85%) as a pale yellow powder.

CssB gHfOzSz (776.5) calcd: C: 58.71 H: 5.96 S: 8.25 found: C: 57.32 H: 5.93 S: 8.14

Example X Dibenzyl {1,4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-methoxyphenoxy)} zirconium (X)

A suspension of 500 mg (1.111 mmol) of the bisphenolate ligand (B) in 10 ml of toluene was cooled to -80 ° C. A solution of 505.5 mg (1.111 mmol) of zirconium tetrabenzyl in 15 ml of toluene was added dropwise. The reaction mixture became more

15 minutes at this temperature and then 1.5 hours at room temperature touched. The solvent was removed in vacuo, the residue washed with pentane and (X) was obtained as a light yellow powder in almost quantitative yield. C ₃₈ H ₄₆ O ₄ S ₂ Zr (720) Calcd: C: 63.23 H: 6.42 S: 8.88 Found: C: 63.10 H: 6.41 S: 8.87

Example XI Dibenzyl {1,4-dithiabutanediyl-2,2'-bis (6-tert-butyl-4-memoxyphenoxy)} hafhium (XI)

Analogously to Example X, the compound (XI) was obtained in almost quantitative yield in the form of a pale yellow powder, starting from 500 mg (1.111 mmol) of the bisphenolate ligand (B) and 1.11 mmol of hafnium tetrabenzyl. C ₃₈ H ₄₆ O ₄ S ₂ Zr (810) Calcd: C: 56.39 H: 5.73 S: 7.92 Found: C: 56.43 H: 5.77 S: 7.83

Example XII DicMoro {1,4-dithiabutanediyl-2,2'-bis (4,6-di-te7 "t-butylphenoxy)} titanium (XII).

0.36 g (1.9 mmol) of titanium tetrachloride was added to a solution of 0.92 g (1.9 mmol) of the bisphenolate ligand (C) from Example C in 20 ml of toluene. The color of the solution immediately changed to red and hydrogen chloride evolution was observed. The red precipitate was isolated and washed with hexane. 1.12 g (98%) of compound (XII) was obtained as a red-orange, microcrystalline powder. EI MS: m / z (%) 620 (100, M ⁺ ), 558 (26, CÄsOÄTiCl ^, 264 (C ₁₆ H ₂₄ OS ⁺ ) 192 (19,

Example XIII DicMoro {1,5-dithiapentanediyl-2,2'-bis (4,6-di-te7'-t-butylphenol)} titanium (XIII).

Analogously to Example XII, compound (XIII) was prepared starting from ligand (D) and titanium tetrachloride. EI MS: m / z (%) 631 (100, M ^{1 "} ), 616 (29, C ₃ oH ₄₃ O ₂ S ₂ TiCl ₂ ⁺ ), 581 (15, C ₃₀ H ₄₃ O ₂ S2TΪCV), 56 ( 29, C ₄ H ₈ ⁺ ).

Example XIV Di (isopropoxy) {1,4-dithiabutanediyl-2,2'-bis (4,6-di-te7 "t-butylphenoxy)} titanium (XTV)

0.54 g (1.9 mmol) of titanium tetraisopropoxide were added at room temperature to a solution of 0.92 g (1.9 mmol) of the bisphenolate ligand (C) from Example C in 20 ml of toluene. The color of the solution immediately turned yellow. The solution was stirred at room temperature for 2 hours, then the solvent was removed in vacuo and the yellow residue was washed with hexane. 1.22 g (99%) of the compound (XTV) were obtained. EI MS: m / z (%) 666 (100) (M ⁺ ), 608 (13, C ₃₃ H ₅₁ O ₃ S ₂ Ti ⁺ ), 549 (4, C ₃₀ H ₄ O2S2T1), 503 (4, M ^ Ti (OC ₃ H ₇ ) ₃ ), 333 (2, (M / 2) ⁺ ).

Example XV di (isopropoxy) {1, 5-dithiapentanediyl-2,2 'bis (4,6-di-ter-t-butylphenol)} titanium (XV).

Compound (XV) was prepared in analogy to, for example, XTV starting from ligand (D) in quantitative yield.

EI MS: m / z (%) 682 (27, M ⁺ ), 623 (5, C ₃₄ H ₅₃ O ₃ S ₂ Ti ⁺ ), 516 (4, C ^ H ^ O ^ *), 56 (29, C ₄ H ₈ ).

Example XVI Dibenzyl {1,4-dithiabutanediyl-2,2'-bis (4,6-di-tert-butylphenoxy)} zirconium (XVI)

To a solution of 2.2 g (4.4 mmol) of the bisphenolate ligand (C) from Example C in 20 ml

Toluene was added at room temperature with 2.0 g (4.4 mmol) of zirconium tetrabenzyl. The color of the solution turned yellow. The solution was stirred at room temperature for 2 hours, then the solvent was removed in vacuo and the pale yellow residue was washed with hexane. Compound (XVI) was obtained quantitatively in the form of a pale yellow microcrystalline powder.

¹³ C { ^X H} NMR (C ₆ D ₆ , 25 ° C) δ: 29.7 (C (CH ₃ ) ₃ ), 31.7 (C (CH ₃ ) ₃ ), 34.4 (C (CH ₃ ) ₃ ), 35.4 (SCH ₂ ), 37.9 (C (CH ₃ ) ₃ ), 59.5 (CH ₂ Ph), 120.3 (para CH ₂ C ₆ H ₅ ), 123.1 (C-2), 126.0 (C-3), 127.8 (meta CH ₂ C ₆ H ₅ ), 130.3 (ortho CH ₂ C ₆ H ₅ ), 137.3 (C-4), 142.6 (C-6), 143.6 (ipso CH ₂ C ₆ H ₅ ), 164.6 (Cl).

Example XVIIDibenzyl {1,4-dithiabutanediyl-2,2'-bis (4,6-di-te7-t-butylphenoxy)} hafnium (XVII)

Analogously to Example XVI, starting from ligand (C) and hafnium tetrabenzyl, compound (XVII) was obtained in quantitative yield.

¹³ C {1H} NMR (C ₆ D ₆ , 25 ° C) δ: 29.7 (C (CH ₃ ) ₃ ), 31.7 (C (CH ₃ ) ₃ ), 34.4 (C (CH ₃ ) ₃ ), 35.4 (C (CH ₃ ) ₃ ), 37.9 (SCH ₂ ), 69.1 (CH ₂ Ph), 120.3 (para CH ₂ C ₆ H ₅ ), 123.1 ( C-2), 126.0 (C-3), 127.8 (meta CH ₂ C ₆ H ₅ ), 130.3 (ortho CH ₂ C ₆ H ₅ ), 137.3 (C-4), 142 , 6 (C-6), 143.6 (ipso CH ₂ C ₆ H ₅ ), 164.6 (Cl).

Example XVTII DicMoro {l-mono1hiaethanediyl-2,2'-bis (6-tert-butyl-4-methylρhenolate) -} titanium (XVIII)

The solution of the bisphenolate ligand (E) (314 mg, 843 μmol) in 10 ml of CH ₂ C1 _{2 was} added dropwise to the solution of titanium tetrachloride (160 mg, 843 μmol) in 10 ml of dichloromethane with stirring at 0 ° C. During this time the reaction solution turned dark red. After the addition was complete, the reaction mixture was allowed to stir at room temperature for 30 minutes and then the volatiles were removed under reduced pressure. 5 ml of pentane were added to the residue, the mixture was stirred for about 15 min and then dried in vacuo. The product was obtained in quantitative yield in the form of a dark red solid. EI-MS (70 eV): m / z = 488 (100%, V), 437 (63%, M * - HCl - CH ₃ ), 381 (17%, iv - CI - CH ₃ -C ₄ H ₉ ), 161 (79%, [OC ₆ H ₂ (C ₄ H ₉ ) CH ₂ ] ⁺ ). Example XLX dichloro {1 -monothiaethanediyl-2- (4,6-di-tgrt-butyl-phenolate) -2 '- (6'-tert-butyl-4'-methylphenolate) -} titanium (XIX)

The compound (XIX) was prepared according to the method described in Example XVIII from 46 mg (242 μmol) TiCl ₄ in 5 mL CH ₂ C1 ₂ and 100 mg (242 μmol) bisphenolate ligand (F) in 5 L CH ₂ C1 ₂ . Yield: quantitative.

EI-MS (70 eV): m / z = 530 (100%, M ⁺ ), 515 (17%, M ⁺ - CH ₃ ), 479 (34%, M ⁺ - HCl -

CH ₃ ).

Example XX dichloro {1-monothia-2-methyl-ethanediyl-2- (6-te7-butyl-4-methylphenolate) -2 '- (6'-tert-butyl-phenolate) -} titanium (XX)

The compound (XX) was prepared as described in Example XVIII from 61 mg (321 μmol) TiCl; in 5 mL CH ₂ C1 ₂ and 115 mg (307 μmol) of the bisphenolate ligand (G) in 5 mL CH ₂ C1 ₂ . Yield: quantitative.

EI-MS (70 eV): m / z = 488 (41%, M), 452 (100%, M ⁺ - HCl), 401 (20%, M ⁺ - 2 CH ₃ - C ₄ H ₉ ).

Example XXI dichloro {1 -monothiaethanediyl-2,2'-bis (6-tert-butyl-4-methylphenolate) -} zirconium (XXI)

The solution of the bisphenolate ligand (E) (80 mg, 215 μmol) in 5 mL CH ₂ C1 _{2 was} added dropwise to the suspension of ZrCL, (50 mg, 214 μmol) in 5 mL CH ₂ C1 ₂ with ice cooling. A clear solution resulted, which was stirred at room temperature for 30 minutes after the addition had ended. After filtering, the volatile constituents of the reaction mixture were removed under reduced pressure and 5 ml of pentane were added. The insoluble product was filtered off and dried in vacuo. 105 mg (197 μmol, 92%) of the metal complex were obtained in the form of a colorless solid. EI-MS (70 eV): m / z = 530 (67%, M ^"1" ), 515 (29%, M ⁴ - CH ₃ ), 479 (52%, l - HCl - CH ₃ ), 423 ( 52%, M ⁺ - CI - CH ₃ - C ₄ H ₉ ). Example XXIIDichloro {1-monothiaethanediyl-2,2'-bis (6-tert-butyl-4-methylphenolate) -} haf ium (XXII)

The compound was prepared according to the same method as Example XXI from 69 mg (215 μmol) HfCl ₄ in 5 L CH ₂ C1 ₂ and 80 mg (215 μmol) ligand (E) in 5 L CH ₂ C1 ₂ . Yield: 120 mg (193 µmol, 90%).

EI-MS (70 eV): m / z = 620 (100%, M ⁺ ), 605 (55%, M ⁺ - CH ₃ ), 569 (25%, M ⁺ - HCl - CH ₃ ), 513 (28 %, f- CI - CH ₃ -C ₄ H ₉ ).

Example XXIII Di-isopropoxy {1-monothiaethanediyl-2,2'-bis (6-fert-butyl-4-methylphenolate) -} titanium (XXIII)

The solution of the ligand (E) (117 mg, 314 μmol) in 10 mL CH _{2 was added} to the solution of the Ti (z-PrO) (90 mg, 317 μmol) in 10 mL CH ₂ C1 ₂ with stirring at - 70 ° C C1 ₂ added dropwise. After the additions were complete, the reaction mixture was slowly warmed to room temperature and the volatile components of the solution were removed under reduced pressure. The residue was taken up in 5 mL pentane and cooled to -70 ° C. The yellow solid which precipitated out after several days was filtered off and dried in vacuo. Yield: 145 mg (270 µmol, 86%). EI-MS (70 eV): m / z = 536 (72%, M ⁺ ), 478 (44%, actual CH ₃ - CH (CH ₃ ) ₂ ), 360 (100%, M ⁺ - OC ₆ H ₂ CH ₂ (C ₄ H ₉ ) CH ₃ ).

Example XXIV Dibenzyl {l-monothiaethanediyl-2,2'-bis (6-tert-butyl-4-methylphenolate) -} titanium (XXTV)

To dissolve Ti (CH ₂ Ph) ₄ (83 mg, 201 μmol) in 3 mL pentane, the solution of the ligand (E) (75 mg, 201 μmol) in 3 mL C ₅ H _{1 was} added dropwise with stirring at room temperature. After 2 h the reaction solution was concentrated and cooled to -30 ° C. The precipitated dark red solid was filtered off and dried in vacuo. Yield: 116 mg (193 µmol, 96%).

EI-MS (70 eV): m / z = 509 (5%, M ⁺ - C ₇ H ₇ ), 91 (100%, C ₇ H ₇ ). Example XXV Dibenzyl {1 -monothiaethanediyl-2,2'-bis (6-te7't-butyl-4-methylphenolate) -} Zirconium (XXV)

The solution of the ligand (E) (75 mg, 201 μmol) in 8 ml of toluene was added to the Zr (CH ₂ Ph) solution (92 mg, 202 μmol) in 8 ml of toluene with stirring at -70 ° C. The reaction mixture was slowly warmed to room temperature and after about 2 hours the volatiles in the solution were removed under reduced pressure. The residue was taken up in 5 mL pentane, filtered and then dried in vacuo. 110 mg (171 μmol, 85%) of the product were obtained in the form of a pale yellow solid.

¹³ C-NMR (100 MHz, C ₆ D ₆ ): δ = 20.9 (CH ₃ ), 21.0 (CH ₃ ), 30.0 (C (CH ₃ ) ₃ ), 30.5 (C ( CH ₃ ) ₃ ), 35.1 (C (CH ₃ ) ₃ ), 35.3 (C (CH ₃ ) ₃ ), 41.6 (CH ₂ S), 57.7 (ZrCH ₂ Ph), 60, 0 (ZrCH ₂ Ph), 122.9 (ipso-C), 123.6 (para CH ₂ C ₆ H ₅ ), 124.1 (para CH ₂ C ₆ H ₅ ), 124.8, 125.7, 128.4, 128.5 (ipso-C), 128.9 (ortho CH ₂ C ₆ H ₅ ), 129.0 (meta CH ₂ C ₆ H ₅ ), 129.3 (C3 '), 130.3 (ipso-C), 130.8 (C5 '), 131.0 (meta CH ₂ C ₆ H ₅ ), 132.2 (C3), 137.1, 137.6, 138.5, 145.4 ( ipso-C), 159.4 (CO), 164.1 (CO).

Example XXVI Dibenzyl {l-monothiaethanediyl-2,2'-bis (6-tert-butyl-4-methylphenolate) -} hafnium (XXVI)

The compound was prepared from 110 mg (202 μmol) of Hf (CH ₂ Ph) ₄ in 10 ml of toluene and 75 mg (201 μmol) of ligand (E) in 10 ml of toluene using the same method as in Example XXV. The product was obtained in quantitative yield as a colorless solid.

¹³ C-NMR (100 MHz, C ₆ D ₆ ): δ = 20.7 (CH ₃ ), 20.8 (CH ₃ ), 30.2 (C (CH ₃ ) ₃ ), 30.7 (C ( CH ₃ ) ₃ ), 35.1 (C (CH ₃ ) ₃ ), 35.4 (C (CH ₃ ) ₃ ), 41.9 (CH ₂ S), 68.3 (HfCH ₂ Ph), 70, 0 (HfCH ₂ Ph), 122.0 (ipso-C), 122.9 (para CH ₂ C ₆ H ₅ ), 124.1 (ipso-C), 124.6 (para CH ₂ C ₆ H ₅ ) , 125.7, 128.1, 128.5 (ipso-C), 128.7 (ortho CH ₂ C ₆ H ₅ , C3 ', C5'), 129.2 (meta CH ₂ C ₆ H ₅ ), 129.3 (ipso-C), 129.8 (ortho CH ₂ C ₆ H ₅ ), 130.1 (meta CH ₂ C ₆ H ₅ ), 130.7 (C5), 132.3 (C3), 135 , 1, 137.8, 138.7, 143.5 (ipso-C), 159.4 (CO), 164.0 (CO). polymerization

Example Pl polymerization of styrene

A 500 mL four-necked flask was placed under a dry argon atmosphere and toluene (150 mL, dried over Na / K alloy), styrene (100 mL, 870 mmol, distilled over CaH ₂ ) and 22.5 ml MAO solution (10 wt. -% in toluene). The reaction mixture was warmed to 40 ° C. The polymerization was started by adding 25 μmol of the transition metal compound (XII) dissolved in 1 ml of toluene. After 2 hours, the polymerization was stopped by adding 10 ml of 2-propanol and the polymer formed was precipitated in 700 ml of HCL-acidic methanol, the product was filtered off and washed several times with methanol. After drying in vacuo at 60 ° C. for 24 hours, the polymer was extracted with 2-butanone in a Soxhlet apparatus in order to remove atactic fractions. 15.5 g of isotactic polystyrene were obtained. The results of the polymer analysis are summarized in Table 1.

Example P2 Polymerization of styrene

The polymerization was carried out analogously to Example P1. 25 μmol of compound (II) was used as the transition metal compound. 5.6 g of isotactic polystyrene were obtained. The results of the polymer analysis are summarized in Table 1.

Example P3 Polymerization of styrene

The polymerization was carried out analogously to Example P1. 25 μmol of compound (XIII) were used as transition metal compound. 1.3 g of syndiotactic polystyrene were obtained. The results of the polymer analysis are summarized in Table 1. Example P4 Polymerization of styrene

The polymerization was carried out analogously to Example P1. The compound (XTV) was used as the transition metal compound instead of compound (XII). 11.9 g of isotactic polystyrene were obtained. The results of the polymer analysis are summarized in Table 1.

Table 1 Compilation of the results of polymer analysis

Example P5 Polymerization of ethylene

The polymerization was carried out at 25 ° C. in a Büchi mini-clave glass autoclave (200 ml). The reactor was filled with toluene and 18 mmol methylaluminoxane as MAO solution (10% in toluene) were added. The reactor was then filled with ethylene until the reaction mixture was saturated with monomer gas. The polymerization was started by adding a solution of 12 μmol of the transition metal compound (XII) in 10 ml of toluene. The ethene pressure was 6 bar. The volume of the reaction mixture was 150 mL. To end the polymerization, the gas pressure was released and 10 ml of 2-propanol were added. The resulting polymer was precipitated in 1 L of HCl-acidic methanol, filtered off xmd at 60 ° C in a vacuum. 16.6 g of polyethylene were obtained, the following values being measured on the polymer: M _n [g / mol] = 2000; M _w / M _n = 3.6; T _m = 120 ° C Example P6 Polymerization of ethylene

The polymerization was carried out analogously to Example 5. Instead of the transition metal compound (XII), 12 μmol of the compound (XIII) was used. 0.3 g of polyethylene were obtained, the following values being measured on the polymer: M _n [g / mol] = 750; M _w / M _n = 2.4; T _m = 135 ° C

Example P7 Polymerization of Ethylene

The polymerization was carried out analogously to Example 5. Instead of the transition metal compound (XII), 12 μmol of the compound (II) was used. 2.9 g of polyethylene were obtained.

Example P8 Polymerization of ethylene

The reactor with 4 mg (8.1 μmol) of the transition metal compound (XVIII) was evacuated three times and filled with ethene. 40 ml of toluene and 10.8 g were then passed through a septum

(40.5 mmol) MAO solution added. The reactor contents were heated to 40 ° C.

The ethene pressure was then increased to 4 bar and kept constant during the reaction. After 15 minutes the reaction was stopped by releasing the ethene pressure.

The reaction mixture was poured into a 10% _. HCl-methanol solution given. The colorless solid which precipitated out and the product which had already been suspended from the solution during the reaction were stirred in the precipitation solution for 2 h. Then that became

Filtered polymer, washed with methanol and hexane, 2 h at 60 ° C in

Oil pump vacuum dried and then analyzed. 679 mg of polymer were obtained.

Example P9 Polymerization of ethylene The polymerization was carried out analogously to Example P8. 4 mg (7.5 μmol) of the transition metal compound (XLX) and 10.1 g (37.5 mmol) of MAO solution were used as the catalyst system. 604 mg of polymer were obtained.

Example P10 Polymerization of ethylene

The polymerization was carried out analogously to Example P8. 4 mg (8.1 μmol) of the transition metal compound (XX) and 10.8 g (40.5 mmol) of MAO solution were used as the catalyst system. 706 mg of polymer were obtained.

Example PlI polymerization of ethylene

The polymerization was carried out analogously to Example P8. 4 mg (7.5 μmol) of the transition metal compound (XXI) and 10.1 g (37.5 mmol) of MAO solution were used as the catalyst system. 948 mg of polymer were obtained.

Example P12 Polymerization of Ethylene

The polymerization was carried out analogously to Example P8. 5 mg (8.0 μmol) of the transition metal compound (XXII) and 10.7 g (40.5 mmol) of MAO solution were used as the catalyst system. 568 mg of polymer were obtained.

Example P13 copolymerization of styrene and ethylene

The polymerization was carried out in a Buchi mini-glass autoclave (200 ml) at 25 ° C. The reactor was filled with toluene and 18.9 ml (165 mmol) styrene and 22.5 mmol memylalumoxane was added as a MAO solution (10% in toluene). J following the reactor was filled with ethylene until the reaction mixture was saturated with monomer gas. The polymerization was started by adding 15 μmol of the transition metal compound (XII) dissolved in 10 ml of toluene. The ethene pressure was ^" 2 bar. The volume of the reaction mixture was 150 mL. At the end of the polymerization, the gas pressure was released and 10 L of 2-propanol were added. The resulting polymer was precipitated in 1 L of HCl-acidic methanol, filtered off and filtered at 60 ° C The products were extracted with acetone to remove comonomer residues, giving 3.8 g of copolymer, on which the following values were determined: M _n [g / mol] = 10800; M _w / M _n = 2 , 4; T _g = 20.8 ° C; styrene incorporation [mol%] according to 1H-NMR = 49.

Example P14 copolymerization of styrene and ethylene

The polymerization was carried out analogously to Example P13. 37.8 ml (330 mmol) of styrene were used in order to double the styrene concentration. All other conditions have been retained. 6.6 g of copolymer were obtained, on which the following values were determined: M _n [g / mol] = 12100; M _w / M _n = 2.2; T _g = 30.5 ° C; Styrene incorporation [mol%] according to 1H-NMR = 55.

Example P15 copolymerization of styrene and ethylene

The polymerization was carried out analogously to Example P13. 9.5 ml (82.5 mmol) of styrene were used to halve the styrene concentration, 7.5 μmol of the transition metal compound (XII) and 11.25 mmol of methylalumoxane were used to also halve the concentration of the catalyst system. All other conditions have been retained. 2.6 g of copolymer were obtained, on which the following values were determined: M _n [g / mol] = 8800; M _w / M _n = 2.3; T _g = 4.5 ° C; Styrene incorporation [mol%] according to 1H-NMR

Claims

claims

Ligand system of formula (I)

wherein

D, D 'can be the same or different and represents oxygen, sulfur, selenium, tellurium, an NR ^π group or PR ^π group,

Y, Y 'can be the same or different and for oxygen, sulfur, selenium,

Tellurium, an NR, π group or PR 11 group,

Is 0 or 1,

R ¹ , R ^{2 can be the} same or different and are hydrogen or a CrC ₄ o-carbon-containing radical, or two radicals R ¹ and R ² together with the carbon atom connecting them or, if q> 1, two radicals R ¹ together with the carbon atoms connecting them a cyclic or form a polycyclic ring system which, in addition to carbon atoms, may contain one or more identical or different heteroatoms selected from the group consisting of the elements N, O, P, S and Si,

q is an integer from 1 to 10,

R ³ to R ^{10 may be the} same or different and are hydrogen or a C1-C ₄₀ carbon-containing radical, or two adjacent radicals R ³ to R ¹⁰ together with the atoms connecting them form a cyclic or polycyclic ring system which, in addition to carbon atoms, in the ring system can contain one or more, identical or different heteroatoms selected from the group consisting of the elements N, O, S and Si,

R ^{11 is} hydrogen or a CrC ₄ o-carbon-containing radical.

Ligand system of formula (I) according to claim 1,

wherein

D, D 'is oxygen,

Y, Y 'is sulfur, and

q is an integer from 1 to 5, preferably 1 to 3.

Transition metal compound of the formula (II)

wherein

M is an element of the 3rd, 4th, 5th, 6, 7th, 8th, 9th or 10th group of the

Periodic table of the elements or an element of the lanthanides is

X, X 'can be the same or different and is an organic or inorganic anionic ligand,

ol, o2 may be the same or different and are 0 or 1, where ol + o2 + 2 corresponds to the oxidation number of M,

D, D 'can be the same or different and for oxygen, sulfur, selenium,

Tellurium, a NR .π ¹ group or PR 1'1 group,

Y, Y 'can be the same or different and stands for oxygen, sulfur, selenium, tellurium, an NR ^π group or PR ^U group,

p is 0 or 1, R ¹ , R ^{2 may be the} same or different and are hydrogen or a C ₁ -C ₀ carbon-containing radical, or two radicals R ¹ and R ² together with the carbon atom connecting them or, if q> 1, two radicals R. ¹ together with the carbon atoms connecting them form a cyclic or polycyclic ring system which, in addition to carbon atoms, may contain one or more identical or different heteroatoms selected from the group consisting of the elements N, O, P, S and Si in the ring system,

q is an integer from 1 to 10,

R ³ to R ^{10 may be the} same or different and are hydrogen or a CrC ₄₀ - carbon-containing radical, or two adjacent radicals R ³ to R ¹⁰ together with the atoms connecting them form a cyclic or polycyclic ring system which contains one or more carbon atoms in the ring system can contain several, identical or different heteroatoms selected from the group consisting of the elements N, O, S and Si,

R ^{11 is} hydrogen or a CrC ₄₀ -containing radical.

4. transition metal compound of formula (II) according to claim 3,

wherein

M is an element of the 4th group of the Periodic Table of the Elements, •

X, X 'independently of one another are a halide, CrCio-alkyl, C ₂ -Cι ₀ alkenyl, C ₆ -Cι aryl, alkylaryl or arylalkyl with 1 to 10 carbon atoms in the alkyl radical and 6 to 14 carbon atoms in the aryl radical, NR'R " - and OR '", where R' and R" are Ci to C ₁₀ , preferably Cr to C ₃ alkyl, particularly preferred are C to C ₂ alkyl radicals and R '"are a Crbis Qo radical, preferably Cr to C ₃ alkyl radical, particularly preferably an i-propyl radical, particularly preferred X and X' are independently i-propyl radicals or halide radicals, preferably selected from chloride and bromide,

ol, o2 is 1,

D, D 'is oxygen,

Y, Y 'is sulfur

q is an integer from 1 to 5, preferably 1 to 3,

and the other variables have the meaning as in formula (II).

5. transition metal compound according to claim 3 or 4, characterized in that p is 1, D is D ', Y is Y' and X is X '.

6. transition metal compound according to one of claims 3 to 5, characterized in that it has C2 symmetry.

7. A catalyst system for the polymerization of unsaturated compounds containing at least one transition metal compound according to one of claims 3 to 6 and at least one cocatalyst.

8. A catalyst system according to claim 7, which additionally contains a support.

9. A process for the preparation of polymers by polymerization or copolymerization of at least one unsaturated compound in the presence of a

Catalyst system according to claim 7 or 8.

10. The method according to claim 9, characterized in that at least one vinyl aromatic compound, preferably styrene, as the unsaturated compound. α-methyl styrene or p-methyl styrene, particularly preferably styrene is used.

11. The method according to claim 10, characterized in that a C2-symmetrical compound is used as claimed in claim 6 ^• transition metal compound.

12. Use of a ligand system according to claim 1 or 2 for the preparation of a transition metal compound.

13. Use of a transition metal compound according to one of claims 3 to 6 or a catalyst system according to claim 7 or 8 for the production of isotactic polystyrene.