Transition metal complexes

Details Transition metal complexes Transition metal complexes

2000-12-12

2002-07-16

Wu, David W. (Department: 1713)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Organic compound containing

C502S104000, C502S117000, C502S152000, C526S160000, C526S161000, C526S170000, C526S172000, C526S943000, C526S348600, C526S351000, C526S352000, C556S011000, C556S053000

Reexamination Certificate

active

06420301

ABSTRACT:

The present invention relates to transition metal complexes of the formula (Ia) or (Ib),
where the substituents and indices have the following meanings:
R
1
to R
3
are hydrogen, C
1
-C
10
-alkyl, 5- to 7-membered cycloalkyl, which in turn may be substituted by C
1
-C
10
-alkyl, are C
6
-C
15
-aryl or arylalkyl, where the radicals together with adjacent radicals in each case with the linking atoms may form a saturated or unsaturated ring having 5 to 15 carbon atoms, or are Si(R
4
)
3
where
R
4
is C
1
-C
10
-alkyl, C
3
-C
10
-cycloalkyl or C
6
-C
15
-aryl,
M is titanium, zirconium, hafnium, vanadium, niobium or tantalum or an element of the IIIrd subgroup of the Periodic Table or of the lanthanoids,
x is fluorine, chlorine, bromine, iodine, hydrogen, C
1
-C
10
-alkyl, C
6
-C
15
-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, —OR
5
or —NR
5
R
6
,
n is 1, 2 or 3, where n is the valency of M minus the number 2,
 where
R
5
and R
6
are C
1
-C
10
-alkyl, C
6
-C
15
-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl having in each case 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical and
the radicals X are identical or different,
Y is
 where
R
7
is C
1
-C
10
-alkyl, C
6
-C
15
-aryl, C
3
-C
10
-cycloalkyl or C
7
-C
18
-alkylaryl or is C
1
-C
10
-alkyl, C
6
-C
15
-aryl, C
3
-C
10
-cycloalkyl or C
7
-C
18
-alkylaryl, each of which is mono- or polysubstituted by Si(R
8
)
3
, SR
8
,
 OSi(R
8
)
3
, N(R
8
)
2
, P(R
8
)
2
or a combination thereof, or is Si(R
8
)
3
where
n′ and m′ are each 1, 2, 3 or 4 and
R
8
is hydrogen, C
1
-C
10
-alkyl, C
6
-C
15
-aryl, which may in turn be substituted by C
1
-C
4
-alkyl groups, or is C
3
-C
10
-cycloalkyl,
where the radicals R
8
are identical or different,
Z is a three-way bridge and
A and A
1
are two-way bridges.
Additionally, the invention relates to processes for preparing the transition metal complexes, to compounds which are employed as intermediates for their preparation, to the use of the transition metal complexes for polymerizing olefins, to processes for polymerizing olefins, to homo- or copolymers of ethylene or of propylene with other C
2
-C
12
-alk-1-enes, to their use for preparing films, fibers or moldings, and to the films, fibers or moldings made from these polymers.
Recently, metallocene catalysts have been used increasingly for polymerizing or copolymerizing ethylene or propylene. In the case of ethylene polymerization, it is frequently desirable to obtain a high content of comonomers such as but-1-ene, hex-1-ene or oct-1-ene in the ethylene copolymers. In the case of propylene polymerization, it is usually attempted to achieve an isotactic structure of the polymer chains. Using metallocene catalysts, these properties can be controlled via the ligand structure.
It is generally assumed that the opening angle between the cyclopentadienyl rings of the metallocene has great influence on the incorporation behavior. A large opening angle can be achieved, for example, by bridging the rings with an SiMe
2
- or C
2
H
4
-bridge. Such metallocene catalysts are described, for example, in EP-A 336 128. Because of the bridging, these complexes can exist both in racemic and in meso form. The racemic metallocenes are particularly suitable for use in propylene polymerization, since stereoselective catalysts are required here. However, it is a disadvantage of these metallocenes that usually a mixture of racemic and meso form is obtained in the synthesis, from which the meso form has to be removed at high expense.
In other metallocene catalysts, a cyclopentadienyl ring is replaced by a heteroligand, for example an amide group. In these metallocenes, the amide group is linked covalently via a bridge (for example SiMe
2
) with the ring system. Compounds of this type are described, for example, in EP-A 416 815 and EP-A 420 436. It is known that metallocene complexes of this type are particularly suitable for incorporating comonomers in the ethylene/&agr;-olefin copolymerization and give a high molar mass. However, it has hitherto not been possible to obtain isotactic polypropylene with complexes of this type, since the metal center did not have C2 symmetry. The resulting polypropylene was atactic with partially syndiotactic portions (WO 94/00500, U.S. Pat. No. 5,096,867, EP-A 520 732, U.S. Pat. No. 5 504 169).
Beside metallocenes having a cyclopentadienyl ring and a heteroatom as ligands, there are also known more complex systems, for example having a fluorenyl system and a heteroatom (Okuda et al., Organometallics 1995, 14, 789-795). However, the chiral metal atom is likewise not obtained. While U.S. Pat. No. 5,026,798 describes the synthesis of partially isotactic polypropylene using catalysts of this type, more recent investigations (A. L. McKnight et al. Organometallics 1997, 16, 2879-2885) show that identical systems achieve only isotacticities which are in the range of what was statistically expected. Thus, the ligand skeleton employed has no influence on the isotacticity.
It is an object of the present invention to remedy the disadvantages described above and to develop a metallocene complex which offers technical advantages in the polymerization of ethylene and shows, in particular, high incorporation of comonomers and affords a high molar mass. Furthermore, the metallocene should be capable of catalyzing the preparation of isotactic polypropylene, where it should likewise afford a high molar mass. Finally, the structure of the metallocene should be such that it can be prepared in a technically simple manner and that, in particular, a meso form which, for many applications, would have to be removed at great expense, can not be generated in the synthesis.
We have found that this object is achieved by the transition metal complexes defined at the outset. Furthermore, we have found processes for their preparation, compounds which are employed as intermediates for their preparation, the use of the transition metal complexes for polymerizing olefins, processes for polymerizing olefins, homo- or copolymers of ethylene or of propylene with other C
2
-C
12
-alk-1-enes, their use for preparing films, fibers or moldings, and the films, fibers or moldings made from these polymers.
The substituents R
1
to R
3
are preferably a hydrogen atom, a C
1
-C
6
-alkyl radical, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, and also the various isomers of pentyl or hexyl, or an aryl radical, such as phenyl or naphthyl, which may be unsubstituted or substituted by alkyl radicals of the group just mentioned. Preference is likewise given to substituents R
1
to R
3
, which form, with adjacent substituents R
1
to R
3
or with substituents of the bridge A
1
, in each case with the linking atoms, a saturated or unsaturated ring having 5 to 10 carbon atoms.
Among the transition metals M in the formulae (Ia) and (Ib), preference is given to the elements of the 4th subgroup of the Periodic Table, i.e. titanium, zirconium and hafnium. Particular preference is given to titanium and zirconium.
Suitable ligands X are in particular the halogens, fluorine, chlorine, bromine and iodine, and particular preference is given to chlorine. Among the C
1
-C
10
-alkyl radicals, methyl, ethyl, propyl and butyl are particularly preferred. The preferred C
6
-C
15
-aryl radical is the phenyl radical.
The number n corresponds to the valency of M minus the number 2, i.e. for the complexes of titanium, zirconium or hafnium, n=2, for the complexes of vanadium, niobium or tantalum, n=3, and for the elements of the 3rd subgroup of the Periodic Table, i.e. scandium, yttrium and lanthanum, and of the lanthanoids, n=1.
Among the heteroligands Y, preference is given to —O—, —S— and
and substituents at the nitrogen atom which may be particularly mentioned are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl, phenyl, benzyl and Si(R
8
)
3
. Preferred substituents at the nitrogen atom

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