Monocyclopentadienyl complexes of chromium, molybdenum or...

Details Monocyclopentadienyl complexes of chromium, molybdenum or... Monocyclopentadienyl complexes of chromium, molybdenum or...

1999-08-13

2002-08-20

Nazario-Gonzalez, Porfirio (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heavy metal containing

C556S012000, C556S021000, C556S060000

Reexamination Certificate

active

06437161

ABSTRACT:

The present invention relates to substituted monocyclopentadienyl, monoindenyl, monofluorenyl and heterocyclopentadienyl complexes of chromium, molybdenum or tungsten in which at least one of the substituents on the cyclopentadienyl ring carries a donor function which is bonded rigidly, not exclusively via sp
3
-hybridized carbon or silicon atoms, and to a process for the polymerization of olefins.
Many of the catalysts used for the polymerization of &agr;-olefins are based on immobilized chromium oxides (see, for example, Kirk-Othmer, “Encyclopedia of Chemical Technology”, 1981, Vol.16, p. 402). These generally give ethylene homopolymers and copolymers of high molecular weights, but are relatively insensitive to hydrogen and thus do not allow simple control of the molecular weight. By contrast, use of bis(cyclopentadienyl)chromium (U.S. Pat. No. 3,709,853), bis(indenyl)chromium or bis(fluorenyl)chromium (U.S. Pat. No. 4,015,059) applied to an inorganic, oxidic support allows simple control of the molecular weight of polyethylene by addition of hydrogen.
As in Ziegler-Natta systems, there has recently also been interest in finding chromium catalyst systems having a uniformly defined active center, so-called single-site catalysts. By targeted variation of the ligand structure, the aim is to be able to modify in a simple manner the activity and copolymerization behavior of the catalyst and the properties of the resultant polymers.
Thus, EP-A-742046 discloses so-called constrained geometry complexes of the group 6, a special process for their preparation (via metal tetraamides), and a process for the preparation of a polyolefin in the presence of such catalysts. The ligand structure consists of an anionic donor which is linked to a cyclopentadienyl radical.
K. H. Theopold et al. in Organomet. 1996, 15, 5284-5286, have described an analogous {[(tert-butylamido)dimethylsilyl](tetramethylcyclopentadienyl)}chromium chloride complex for the polymerization of olefins. This complex selectively polymerizes ethylene. It is not possible either to incorporate comonomers, for example hexene, nor to polymerize propene.
This disadvantage can be overcome by using structurally very similar systems. For example, DE-A1-19710615 describes monocyclopentadienylchromium compounds substituted by donor ligands which can be used, for example, to polymerize propene as well. The donor in these compounds is from the 15th group of the Periodic Table of the Elements and is neutral. The donor is bonded to the cyclopentadienyl ring via a (ZR
2
)
n
fragment, where R is hydrogen, alkyl or aryl, Z is an atom from which the 14th group of the Periodic Table of the Elements, and n is 1. DE-A1-19630580 states that the combination of Z=carbon with an amine donor gives good results.
WO-A-96/13529 describes reduced transition-metal complexes from Groups 4 to 6 of the Periodic Table of the Elements with polydentate monoanionic ligands. These include, inter alia, cyclopentadienyl ligands, preferably containing a donor function bonded via a (CR
2
)
p
bridge, where R is hydrogen or a hydrocarbyl radical having 1 to 20 carbon atoms, and p is 1 to 4. The preferred transition metal is titanium.
There are also ligand systems in which the donor group is linked rigidly to the cyclopentadienyl radical. Such ligand systems and their metal complexes are reviewed, for example, by P. Jutzi and U. Siemeling in J. Organomet. Chem. (1995), 500, 175-185, Section 3. M. Enders et al., in Chem. Ber. (1996), 129, 459-463, describe 8-quinolyl-substituted cyclopentadienyl ligands and their titanium and zirconium trichloride complexes. 2-Picolylcyclopentadienyltitanium trichloride in combination with methylaluminoxane has been used by M. Blais, J. Chien and M. Rausch in Organomet. (1988), 17 (17) 3775-3783 for the polymerization of olefins.
It is an object of the present invention to find novel catalyst systems which can easily be modified and are suitable for the polymerization of &agr;-olefins.
We have found that this object is achieved by substituted monocyclopentadienyl, monoindenyl, monofluorenyl, and heterocyclopentadienyl complexes of chromium, molybdenum or tungsten in which at least one of the substitutents on the cyclopentadienyl ring carries a donor function which is bonded rigidly, not exclusively via sp
3
-hybridized carbon or silicon atoms.
We have furthermore found a process for the polymerization or copolymerization of olefins in which olefins are polymerized in the presence of the following components:
(A) a substituted monocyclopentadienyl, monoindenyl, monofluorenyl or heterocyclopentadienyl complex as claimed in claim
1
, of the formula I
[Y—M—X
n
]
m
  I,
where:
M is chromium, molybdenum or tungsten
Y is described by the formula II
where:
E
1
-E
5
are carbon or a maximum of one E
1
to E
5
is phosphorus or nitrogen,
Z is NR
5
R
6
, PR
5
R
6
, OR
5
, SR
5
or an unsubstituted, substituted or fused, partially unsaturated heterocyclic or heteroaromatic ring system, is one of the following groups:
 and in addition, if Z is an unsubstituted, substituted or fused, partially unsaturated heterocyclic or heteroaromatic ring system, may alternatively be
where
L
1
and L
2
are silicon or carbon,
k is 1, and is alternatively 0 if Z is an unsubstituted, substituted or fused, partially unsaturated heterocyclic or heteroaromatic ring system,
X independently of one another, are fluorine, chlorine, bromine, iodine, hydrogen, C
1
-C
10
-alkyl, C
2
-C
10
-alkenyl, C
6
-C
20
-aryl, alkylaryl having 1-10 carbon atoms in the alkyl radical and 6-20 carbon atoms in the aryl radical, NR
15
R
16
, OR
15
, SR
15
, SO
3
R
15
, OC(O)R
15
, CN, SCN, &bgr;-diketonate, CO, BF
4
−
, PF
6
−
, or a bulky, non-coordinating anion,
R
1
-R
16
independently of one another, are hydrogen, C
1
-C
20
-alkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6-20 carbon atoms in the aryl radical, or SiR
17
3
, where the organic radicals R
1
-R
16
may also be substituted by halogens, and in each case two geminal or vicinal radicals R
1
-R
16
may also be linked to form a five- or six-membered ring,
R
17
independently of one another, are hydrogen, C
1
-C
20
-alkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6-20 carbon atoms in the aryl radical, and in each case two geminal radicals R
17
may also be linked to form a five- or six-membered ring,
n is 1, 2 or 3, and
m is 1, 2 or 3,
(B) if desired, one or more activator compounds, and
(C) if desired, one or more additional conventional olefin-polymerization catalysts.
We have furthermore found olefin polymers obtainable by the process according to the invention, and fibers, films and moldings which comprise the olefin polymers according to the invention.
In order to make the bonding to the cyclopentadienyl ring rigid, the most direct link to the donor function contains at least one sp- or sp
2
-hybridized carbon atom, preferably at least one to three sp
2
-hybridized carbon atoms. The direct link preferably contains an unsaturated double bond or an aromatic ring or forms with the donor a partially unsaturated or aromatic heterocyclic system.
The cyclopentadienyl ring is 5 bonded to the metal center, preferably chromium, in the complexes according to the invention and can also be a heterocyclopentadienyl ligand, i.e. the at least one carbon atom may also be replaced by a heteroatom from Group 15 or 16. In this case, a C
5
ring carbon atom is preferably replaced by phosphorus. In particular, the cyclopentadienyl ring is substituted by further alkyl groups, which can also form a five- or six-membered ring, for example tetrahydroindenyl, indenyl, benzindenyl or fluorenyl.
The donor is a neutral functional group containing an element from the 15th or 16th group of the Periodic Table of the Elements, for example amine, imine, carboxamide, carboxylate, ketone (oxo), ether, thioketone, phopshine, phosphite, phosphine oxide, sulfonyl or sulfonamide,

Affiliated with

Also associated with

Rating

Monocyclopentadienyl complexes of chromium, molybdenum or... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Monocyclopentadienyl complexes of chromium, molybdenum or..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Monocyclopentadienyl complexes of chromium, molybdenum or... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2907421