Diastereomeric amido functionalized ansa half-sandwich complexes of titanium and zirconium as catalyst precursors for ethylene polymerization to give resins with bimodal molecular weight distributions

Article abstract of DOI:10.1016/S1381-1169(01)00171-6

A total of 20 diastereomeric amido functionalized ansa half-sandwich dichloride complexes of titanium and zirconium have been prepared and characterized. All complexes were used as catalyst precursors for ethylene polymerization. Since such catalysts consist of diastereomers they have the potential to produce resins with a bimodal molecular weight distribution.

Full text of DOI:10.1016/S1381-1169(01)00171-6

Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
Diastereomeric amido functionalized ansa half-sandwich
complexes of titanium and zirconium as catalyst precursors
for ethylene polymerization to give resins with bimodal
molecular weight distributions
Alexander Reb, Helmut G. Alt∗
Laboratorium für Anorganische Chemie der, Lehrstuhl fur Anorganische Chem., Universitat Bayreuth,
Postfach 10 12 51, D-95440 Bayreuth, Germany
Received 9 January 2001; accepted 19 March 2001
Abstract
A total of 20 diastereomeric amido functionalized ansa half-sandwich dichloride complexes of titanium and zirconium
have been prepared and characterized. All complexes were used as catalyst precursors for ethylene polymerization. Since
such catalysts consist of diastereomers they have the potential to produce resins with a bimodal molecular weight distribution.
© 2001 Elsevier Science B.V. All rights reserved.
Keywords: Group IV metal; Ansa half-sandwich complexes; Ethylene polymerization; Homogeneous polymerization; Bimodal polyethylene
1. Introduction
So far all published ansa half-sandwich com-
plexes possess a dimethylsilylene unit as a bridge
between the nitrogen atom and the aromatic lig-
and. It was the intention to substitute one methyl
substituent at the silicon atom in order to generate
a center of chirality. The activation of such cat-
alyst precursors with methylaluminoxane (MAO)
should produce diastereomers with individual cat-
alytic properties. The results of such investigations are
reported.
Since the discovery of amido functionalized ansa
half-sandwich complexes of titanium in 1990 [1] these
compounds gained widespread importance as cata-
lysts for the polymerization of olefins. Due to their
good copolymerization properties [2–6] and their abil-
ity to produce high molecular weight linear low den-
sity polyethylene [7] (LLDPE) the commercial value
of ansa-amido catalysts increases [8–28]
2. Results and discussion
2.1. Preparation of the complexes
The desired mono substituted cyclopentadienyl and
indenyl complexes were prepared according to the fol-
lowing reaction Scheme 1.
∗ Corresponding author. Tel.: +49-921552555;
fax: +49-921552157.
E-mail address: helmut.alt@uni-bayreuth.de (H.G. Alt).
1381-1169/01/$ – see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S1381-1169(01)00171-6

36
A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
Scheme 1. Synthesis of diastereomeric amido functionalized ansa half-sandwich complexes.
The following complexes (diastereomers) were syn-
thesized according to this method:
only one optically active center is present (Si atom),
four different stereoisomers can be distinguished.
Due to the existence of these four stereoisomeric
amido half-sandwich complexes that are formed
“automatically” in the complexation step, four differ-
ent catalysts for olefin polymerization are obtained
after the activation with MAO.
Two isomers produce the same polyolefin since
the R-form is the mirror image of the correspond-
ing S-form. The E- and Z-forms, however, exhibit
completely different orientations of both equatorial
substituents on the silicon atom. Therefore, they are
different catalysts and the E- and Z-forms produce
individual polyethylenes that are different from each
other. Thus, the E-(R)-form would produce exactly
the same polyethylene as the E-(S)-form and the
Z-(R)-form the same polyolefin as the Z-(S)-form.
Consequently, such a catalyst is expected to produce
a bimodal polymer.
Ligand precursors containing four different sub-
stituents on the bridging silicon atom possess two
neighbouring chiral centers and consist of two di-
astereomers. During the complexation step, two di-
astereomeric half-sandwich compounds are formed
(Figs. 1 and 2).
In the indenyl series the Z-form is present when
the substituent Rꢀ is in the spatial proximity of the
six-membered ring of the indenyl structure. The
E-form exists when the substituent points away from
the six-membered ring. Z- and E-form possess a mir-
ror image each with different sense of rotation of the
substituents on the silicon atom. The structure with
clockwise decreasing priority of the substituents is
described as R-form, the one with increasing priority
as S-form [29]. Both mirror images do not coincide.
Therefore, they are enantiomers. Despite the fact that

A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
37
Fig. 1. Overview of the diastereomeric amido functionalized ansa half-sandwich complexes. Only one isomer of the diastereomers is shown.
Fig. 2. Amido functionalized ansa half-sandwich complexes with four different substituents on the silicon atom consist of four stereoisomers.

38
A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
2.2. NMR spectroscopic characterization of 5a/b
In the J-modulated 13C NMR spectrum of com-
pound 5a/b (Fig. 4) almost all signals appear doubled.
Especially the signals for the methyl group 1 on the
silicon atom and the signals for the CH-groups of both
vinyl groups 2 show two resonances each. A closer
examination of the sections for the methyl groups 12,
13 and 14 from the J-modulated 75.47 MHz 13C NMR
spectrum proves that even those signals are repre-
sented twice. The resonance signals for the quaternary
carbon atoms of the indenylidene ring also appear as
a double set.
In the 1H NMR spectrum of complex 5a/b (Fig. 3),
two sets of signal groups reveal the existence of two
isomers. The best separation of the signals for the pro-
tons of both diastereomers is achieved when they are
in a different environment as the methyl groups on
the silicon atoms (δ = 0.84 and 0.66 ppm). The aro-
matic proton 9 gives a singlet for each diastereomer
(δ = 6.56 and 6.44 ppm). The two signal sets of the
vinyl group are in the region of δ = 6.69–6.03 ppm.
They appear as overlapping resonance signals of two
ABX-spin systems. The effect of the asymmetric cen-
ter on neighbouring atoms is obvious for protons 20
and 23. While the doublet of the protons 20 for both
diastereomers overlap at δ = 7.54 ppm (the signal has
the double intensity), proton 23 exhibits separated res-
onances at δ = 7.92 and 7.76 ppm due to the different
spatial influence of the vinyl group for both diastere-
omers. The signals of the hex-5-enyl group exhibit for
the E- and Z-form only marginal differences in their
chemical shifts. However, they are visible as overlap-
ping coupling pattern.
According to the signal intensities from the 1H and
13C NMR spectra, both diastereomers exist in the same
ratio.
A 2D 13C, 1H correlation spectrum [HXCOBI]
of complex 5a/b (Fig. 5) confirms the assignment
of the signals made from the one-dimensional 1H
and 13C NMR spectra. The F1 projection is the pos-
itive, internal representation of the 2D spectrum.
The F2 projection is the external projection from
the one-dimensional 1H NMR spectrum. Since the
splitting pattern is so complex, an additional internal,
positive projection from the 2D NMR spectrum (low
Fig. 3. 1H NMR spectrum of 5a/b (25◦C, C6D6). The aryl area becomes very complex due to overlapping of the signals of both
diastereomers. The methyl groups (1) give clearly separated signals. S: C6D6.

A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
39
1
Fig. 4. J-modulated 62.69 MHz 13C{ H} NMR spectrum of 5a/b (25◦C, C6D6). Almost all signals appear doubled due to two diastereomers.
The enlarged partial spectra are derived from sections of the J-modulated 75.47 MHz 13C NMR spectrum (25◦C, C6D6). S: C6D6.
resolution 1H {1H} NMR spectrum) is shown for
better assignment of the centers of the signals on the
F2 axis to the cross signals.
Group II also consists of a double set of signals cor-
responding to the CH-correlations in the vinyl groups
of the E- and Z-form.
Three resonance groups are found of which group I
is formed by two signal groups with four cross signals
each that are attributed to the aromatic CH-groups of
the six-membered ring of both diastereomers.
Group III confirms the assignment of both strongest
signals in the vinyl group area of the H NMR spec-
trum to the corresponding carbons 9 of both diastere-
omers.
1

40
A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
Fig. 5. 2D 1H, 13C NMR correlation spectrum of 5a/b. The four cross signals for both diastereotop vinyl groups and the cross signals for
the six-membered ring of the indenylidene ligand are well resolved.
The 29Si and the 15N NMR spectrum also show dif-
ferences in the chemical shifts of both diastereomers.
These nuclei were recorded using an INEPTRD-pulse
2.3. 29Si NMR spectroscopy as a probe for the
reaction control
2
sequence. J(29Si,1 H) = 7.5 Hz was selected as ex-
The 29Si NMR spectroscopy plays a decisive
role for the characterization of the amido function-
alized ansa half-sandwich complexes as probe for
citing coupling for the polarization transfer of 29Si and
3J(15N,1 H) = 2.5 Hz for 15N.

A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
41
the reaction control. The chemical shift of the 29Si
NMR signal is dependent on two essential factors.
On one hand, the silicon shift is influenced by the
angles formed by the substituents surrounding the
silicon atom. However, these angles remain almost
constant in amido functionalized ansa half-sandwich
complexes as it is described in previous publications
[30–33]. Therefore, the chemical shift of the 29Si
NMR signal does not vary significantly within this
compound type. The substituents on the silicon atom,
however, have a substantial impact on the chemical
shift of the 29Si NMR signal due to their shielding or
deshielding effect.
For compounds containing two methyl groups
on the bridging silicon atom, the 29Si NMR signal
appears at δ = −20 ppm ( 1 ppm) for all synthe-
sized half-sandwich complexes. If one of the methyl
groups is substituted by a vinyl group, the 29Si
NMR Signal is shifted to lower field by 11 ppm.
The phenyl group has less shielding effect (9 ppm to
lower field). The chemical shift moves to lower field
by about 16 ppm when finally both methyl groups
are substituted by two phenyl groups. In contrast,
the 29Si NMR signal of the synthesized complexes
is neither influenced by the substituents on the aro-
matic system, nor by the aromatic system itself
(cyclopentadienylidene-, indenylidene-, fluorenyli-
dene ligand) nor by the substituent on the nitrogen
atom as long as the transition metal compounds of
group IV are used. Hence, the chemical shift of
the 29Si NMR signal is predictable for each amido
functionalized ansa half-sandwich complex as long
as both substituents of the silicon atom are known.
Therefore, besides 1H NMR spectroscopy, the 29Si
NMR spectroscopy serves as an important tool for
the reaction control during the synthesis of these
compounds.
2.4. Homogeneous ethylene polymerization
All complexes were activated with MAO and
tested for homogeneous ethylene polymerization. The
high temperature gel permeation showed a bimodal
molecular weight distribution for all resins. Only the
resins obtained from the cyclopentadienyl catalysts
were monomodal but had a broad molecular weight
distribution.
The diastereomeric complex 13a/b produces bi-
modal polyethylene under homogeneous catalysis
conditions. The four-fold differently substituted sil-
icon atom and the asymmetric indenylidene ring
(the indenylidene ring does not contain a plane of
symmetry) are the reason for the existence of two
diastereomers. Each of the diastereomers produces a
specific polymer. The molecular weight distribution
for both components of the polymer is indicated by
dotted Gauss curves in Figs. 6–9. The low molecular
component of the polymer mixture has a molecular
Fig. 6. 49.69 MHz 29Si INEPTRD NMR spectrum and 25.35 MHz 15N INEPTRD NMR spectrum of 5a/b.

42
A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
Fig. 7. Impact of the substituents on the bridging atom on the chemical shift of the 29Si NMR signal. M: group IV metal.
¯
weight Mw of ca. 570,000 g/mol. The number aver-
silicon atom that forms a chiral center is responsible
for this effect.
¯
age of the high molecular portion is found at Mw
≈
1, 600, 000 g/mol. The HT-GPC diagram is shown in
Fig. 8.
3. Experimental
Compound l7a/b only differs from 13a/b by a miss-
ing propyl substituent in position 1 of the indenylidene
ligand. A substituent on the indenylidene ring is not
required for the asymmetry of the complex since the
indenylidene ligand itself is asymmetric (does not ex-
hibit a plane of symmetry). For the same reasons as for
complex l3a/b the compound consists of two diastere-
omers. Again, the asymmetric indenylidene ligand in
combination with the four-fold differently substituted
3.1. General working techniques
All the work was routinely carried out using
Schlenk technique. Dried and purified argon was used
as inert gas. The solvents used (toluene, n-pentane,
diethylether, THF) were purified in reflux distills
under argon atmosphere with Na/K alloy. Ether
was additionally distilled over lithium aluminum
Fig. 8. HT-GPC diagram of the polyethylene obtained from l3a/b.

A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
43
Fig. 9. HT-GPC diagram of the polyethylene obtained from 17a/b.
hydride. Methylene chloride was dried with CaH2.
Deuterated solvents, such as deuterochloroform-d1
and benzene-d6 were dried over molecular sieves
(300 pm), degassed and stored under inert gas at-
mosphere. Dry ice/isopropanol cooling mixtures
(−78◦C) were used to cool the reactions.
nal of the solvent (δ = 7.24 ppm for chloroform, δ =
7.15 ppm for benzene) and in 13C NMR spectra to the
solvent signal (δ = 77.0 ppm for chloroform-d1, δ =
128.0 ppm for benzene-d6). Tetramethylsilane (δ =
0.0) was used for 29Si NMR spectra and MeNO2 (δ =
0.0) for 15N NMR spectra as external standard.
Prior to use commercial indene was distilled and
stored at −30◦C. Cyclopentadiene was freshly ob-
tained by distillation of the dimer. MAO was supplied
by Witco Company, Bergkamen, as 30% solution in
toluene. All other starting materials are commercially
available and were used without further purification.
3.3. Gas chromatography
Gas chromatograms were recorded using
a
Perkin–Elmer Auto System gas chromatograph with
flame ionization detector (FID) and helium as carrier
gas (1 ml/min).
Temperature program.
3.2. NMR spectroscopy
Starting phase: 3 min at 50◦C.
Heating phase: 5◦C/min (15 min).
Plateau phase: 310◦C (15 min).
The spectrometers Jeol FX 90Q, Jeol JNM-EX 270
E, Bruker ARX 250, Bruker AC 300 and Bruker DRX
500 were available for the recording of NMR spectra.
The organometallic compounds were filled under ar-
gon and measured at 25◦C. The chemical shifts in 1H
NMR spectra are referred to the residual proton sig-
3.4. Differential scanning calorimetry (DSC)
The melting points of the polymer samples were
determined using a Perkin–Elmer DSC-200 instru-

44
A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
ment. Therefore, 3–5 mg each of the dried polymer
were fused into standard aluminum pans and mea-
sured using the following temperature program, first
heating phase (20 K/min) from 320 to 470 K, cooling
phase (−50 K/min) to 320 K, second heating phase
(10 K/min) from 320 to 470 K. The peak maximum
of the second heating curve was indicated as melting
point.
sure relief valve, 5 g (206 mmol) magnesium turnings
were slurried in 100 ml diethylether. Then 24.9 g
(206 mmol) allylbromide in 50 ml diethylether were
added dropwise. The reaction mixture was stirred for
3 h at room temperature. At 0◦C, the generated allyl-
magnesiumbromide was added dropwise to 32.0 ml
(300 mmol) methyltrichiorosilane using a dropping
funnel and stirred for 3 h. Allylmethyldichlorosilane
was directly distilled from the reaction solution.
3.5. High temperature gel permeation
chromatography (HAT-GPC)
3.8. General synthesis procedure for substituted
cyclopentadienyl alkenyl methyl chlorosilane
derivatives
The polymers were measured with a HT-GPC
15◦C apparatus of Millipore Waters Company.
Four successive columns filled with cross-linked
polystyrene were used for separation. The pore di-
ameter of the individual columns was 500, 1000,
10,000 and 100,000 Å. The detection was refrac-
tometric, using a RI Waters 401 refractometer.
Degassed 1,2,4-trichlorobenzene was used as elu-
ent (flow rate 1 ml/min). The polymer samples
were dissolved in boiling 1,2,4-trichlorobenzene.
The measurements were conducted at 150◦C.
The apparatus was calibrated using a polystyrene
standard.
At −78◦C, 41.5 mmol (26.0 ml) n-butyllithium
were added dropwise to 41.5 mmol substituted cy-
clcopentadiene in 150 ml diethylether. The solution
was stirred for 8 h. The solvent was removed in
vacuo.
The lithium salt was added in portions to 83 mmol
alkenylmethyldichlorosilane in 200 ml diethylether
at −78◦C within 30 min. The solution was stirred
for another 12 h. The suspension was filtered over
sodium sulfate, the solvent was evaporated and the
obtained yellow liquid was distilled in vacuo. Yields
59–80%.
3.6. General synthesis procedure for
ω-alkenylmethyldichlorosilane derivatives
3.9. General synthesis procedure for substituted
indenylchlorosilane derivatives
0.5 mol of the corresponding 1,␻-alkadiene was
charged into a three necked flask equipped with re-
flux condenser, thermometer and dropping funnel at
room temperature. 300 mg bis-[(2-Phenylethyn-l-yl)-
methylphenylcarbinol]platinu (0) [34] were dis-
solved. About 31.09 ml (0.3 mol) recondensed
dichloromethylsilane were added dropwise under
slight reflux. The addition of methyl dichlorosilane
was controlled in a way that the temperature did not
exceed 45◦C. After the addition was finished, the
mixture was stirred for another 60 min at room tem-
perature. The subsequent distillation produced the
respective product in 50–60% yields.
80 mmol of the corresponding indene derivative
was dissolved in 150 ml diethylether and cooled to
−78◦C. The equimolar amount of n-butyllithium was
added dropwise using a syringe and stirred for 4 h at
room temperature. The lithium salt was added to the
equimolar amount of the corresponding dichlorosi-
lane compound in 100 ml diethylether at −78◦C and
the solution was stirred for 12 h. The reaction solu-
tion was filtered over sodium sulfate and the solvent
was removed. The product was obtained in 80–96%
yields.
3.10. General synthesis procedure for
cyclopentadienyl ligand precursors
3.7. Synthesis procedure for
allylmethyldichlorosilane
39.2 mmol of the corresponding substituted cy-
clopentadienyl alkylmethylchlorosilane in 200 ml
pentane was mixed at 0◦C with 98 mmol (10.3 ml)
In a three necked flask, cooled to 0◦C, equipped
with a dropping funnel, reflux condenser and pres-

A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
47
Table 2
Polymerization data
¯
Complex
Activity
([g]PE/[mmol] M h)
GPC (Mw)[g/mol]);
DSC (Mp. [◦C]);
(Mn [g/mol]); (HI)
(
Hm [J/g]); (αa,b
)
¯
¯
la/b
1024000
37530
27.28
1516000
182900
8.29
1310000
300800
4.36
>1100000c
n.d.
2529
n.d.
n.d.
n.d.
n.d.
n.d.
133.6
69.4
23.9
2a/b
2654
291
3a/b
4a/b
138.4
115.9
40.0
1964
3504
1006
9139
2657
1049
2308
3959
1054
4790
2395
3164
1245
2060
5a/b
1322000
256600
5.15
955000
70420
137.5
124.0
42.8
135.8
102.4
35.3
134.9
89.8
31.0
137.2
93.8
32.3
138.8
126.5
43.6
135.6
103.4
35.7
139.1
144.8
50.0
142.8
138.7
47.8
140.0
104.2
35.9
138.9
111.4
38.4
135.8
96.5
33.3
140.4
143.7
49.6
138.7
114.4
39.4
6a/b
13.53
>1100000c
7a/b
8a/b
>1100000c
>1100000c
9a/b
l0a/b
11a/b
12a/b
13a/b
14a/b
15a/b
16a/b
17a/b
788300
168700
4.67
610100
19820
30.8
990000
142000
6.94
2065000
254000
8.13
813600
33180
24.52
1043000
404600
25.77
1415000
142700
9.92
1463000
152000
9.62

48
A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
Table 2 (Continued)
¯
Complex
Activity
([g]PE/[mmol] M h)
GPC (Mw)[g/mol]);
DSC (Mp. [◦C]);
(Mn [g/mol]); (HI)
( )
Hm [J/g]); (αa,b
¯
¯
18a/b
>1100000c
135.2
38.5
345
13.3
19a/b
20a/b
>1100000c
138.3
122.9
42.4
1624
2171
333100
12070
27.59
139.2
64.4
22.2
a Maximum of the◦melting pea◦k during the second heating course of the DSC.
b α = Hm/ Hm with Hm = 290 J/g [34].
c New styra gel HT6E-GPC-column, molecular weight too high; n.d.: not determined.
t-butylamine (2.5-fold excess). The solution was
stirred for 12 h. The white t-butylammoniumchloride
was separated in a frit over sodium sulfate, the solvent
was evaporated and the residue was distilled. Yields
65–80%.
with 18 mmol (4.99 g) PbCl2 at room temperature
and the reaction mixture was stirred for 30 min. The
precipitated elemental lead and lead dichioride settled
in the reaction solution after stop stirring, the liquid
was separated using a cannula. The solvent was evap-
orated in vacuo, the residue was dissolved in pentane
and the precipitated lithium salt was separated over a
frit. After removing the solvent, the complex was ob-
tained as deep red to black solid. Yields 65–95%. The
complexes were characterized by NMR spectroscopy
(Table 1).
3.11. General synthesis procedure for
indenyl ligand precursors
80 mmol of the corresponding indenyl chlorosilane
compound was dissolved in 200 ml methylene chlo-
ride and 200 mmol t-butylamine was added quickly.
After stirring for 12 h the solvent was removed, the
residue was dissolved in 200 ml pentane and the sus-
pension was filtered over sodium sulfate. The solvent
was reduced in volume. The ligand precursors were
obtained quantitatively as yellow to light red oils.
3.13. General synthesis procedure for amido
functionalized ansa half-sandwich complexes of
zirconium
About 18 mmol of the respective ligand precursor
in diethylether was charged to a cooled flask (−78◦C)
and mixed with 22.5 ml (36 mmol) n-butyllithium. The
reaction mixture was stirred for 8 h at room tempera-
ture. The equimolar amount of zirconium tetrachior-
ide (4.19 g) was added and the reaction solution was
stirred for additional 12 h. The precipitating lithium-
chloride was filtered, ether was evaporated in vacuo
and the residue was dissolved in pentane. The precipi-
tating solid was filtered again, the solvent was reduced
in volume to almost dryness and the solution was
stored at −78◦C for 24 h. The complex precipitated as
yellow-white solid and could be dried in vacuo. Yields
19–30%. The complexes were characterized by NMR
spectroscopy (Table 1).
3.12. General synthesis procedure for amido
functionalized ansa half-sandwich complexes of
titanium
18 mmol of the respective ligand precursor in di-
ethyl ether was charged to a flask at −78◦C and
22.5 ml (36 mmol) n-butyllithium was added with
a syringe. The reaction mixture was stirred for 8 h
at room temperature. The equimolar amount of
the dilithium salt solution of the ligand was added
slowly to 18 mmol (6.64 g) TiC13·3THF in 100 ml di-
ethylether at −78◦C. The mixture was stirred for 10 h.
For oxidation, the titanium(III) compound was mixed

A. Reb, H.G. Alt / Journal of Molecular Catalysis A: Chemical 174 (2001) 35–49
49
4. Polymerization of ethylene
[12] J.C. Stevens, D.R. Neithammer, Eur. Pat. Appl. 0 418 044
A2 (1991).
[13] R.B. Pannell, J.A.M. Canich, G.G. Hlatky, PCT Int. Appl.
WO 94/005000 (1994).
[14] J.A.M. Canich, US Patent No. 5,096,867 (1992).
[15] P. Brant, J.A.M. Canich, PCT Int. Appl. WO 93/12151 (1993).
[16] P. Brant, J.A.M. Canich, N.A. Merril, PCT Int. Appl. WO
93/21242 (1993).
[17] P. Brant, J.A.M. Canich, A.J. Dias, R.L. Bamberger, G.F.
Liccardi, P.M. Henrichs, PCT Int. Appl. 94/07930 (1994).
[18] J.A.M. Canich, PCT Int. Appl. WO 96/00244 (1996).
[19] R.E. LaPointe, R.K. Rosen, P.N. Nickias, Eur. Pat. Appl. 0
495 375 A2 (1992).
10–15 mg of the corresponding complex were dis-
solved in 50 ml toluene. A solution containing 1–3 mg
complex was taken and activated with MAO (30%
in toluene) (metal:Al = 1:2500). The catalyst solu-
tion was dissolved in 250 ml pentane, charged to a 1 L
Büchi laboratory autoclave and thermostated at 60◦C.
After the inside temperature was calibrated to 60◦C an
ethylene pressure of 10 bar was applied and the mix-
ture was stirred for 1 h at 60 ( 2)◦C. The obtained
polymer was dried in vacuo. The polymerization re-
sults and the physical data of the polymers are shown
in Table 2.
[20] R.E. LaPointe, J.C. Stevens, P.N. Nickias, M.H. McAdon,
Eur. Pat. Appl. 0 520 732 Al (1992).
[21] S.Y. Lai, J.R. Wilson, G.W. Knight, J.C. Stevens, PCT Int.
Appl. WO 93/08221 (1993).
[22] R.K. Rosen, P.N. Nickias, D.D. Devore, J.C. Stevens, F.J.
Timmers, US Patent No. 5,374,696 (1994).
[23] D.D. Devore, L.H. Crawford, J.C. Stevens, F.J. Timmers,
R.D. Russel, D.R. Wilson, R.K. Rosen, PCT Int. Appl. WO
95/00526 (1995).
[24] P.N. Nickias, M.H. McAdon, J.T. Patton, PCT Int. Appl. WO
97/15583 (1997).
[25] B.A. Harrington, PCT Int. Appl. WO 96/40806 (1996).
[26] B.A. Harrington, G.G. Hlatkey, J.A.M. Canich, N.A. Merril,
US Patent No. 5,635,573 (1997).
[27] H.G. Alt, K. Föttinger, W. Milius, J. Organomet. Chem. 564
(1998) 115.
[28] H.G. Alt, K. Föttinger, W. Milius, J. Organomet. Chem. 572
(1999) 21.
[29] L. Stryer, Biochemistry, Spektrum der Wissenschafien
Verlagsgesellschaft mbH, 1990,p. 412.
[30] J. Okuda, F.J. Schattenmann, S. Wocadlo, W. Massa,
Organometallics 14 (1995) 789.
[31] K.E. du Plooy, U. Moll, S. Wocadlo, W. Massa, J. Okuda,
Organometallics 14 (1995) 3129.
[32] J. Okuda, T. Eberle, T.B. Spaniol, Chem. Ber. 130 (1997)
209.
[33] J. Okuda, K.E. du Plooy, W. Massa, H.-C. Kang, U. Rose,
Chem. Ber. 129 (1996) 275.
[34] G. Chandra, P.Y. Lo, P.B. Hitchcock, M.F. Lappert,
Organometallics 6 (1984) 191.
Acknowledgements
We thank Phillips Petroleum Company (Bartlesville,
OK, USA) for the financial support and Witco com-
pany for a donation of MAO.
References
[1] J. Okuda, Chem. Ber. 123 (1990) 1649.
[2] K. Soga, J. Park, T. Shiono, Polym. Commun. 10 (1991) 310.
[3] C. Pellecchia, A. Proto, A. Zambelli, Macromolecules 25
(1992) 4490.
[4] P. Aaltonen, J. Seppälä, Eur. Polym. J. 30 (1994) 683.
[5] G. Xu, Macromolecules 31 (1998) 2395.
[6] F.G. Sernetz, R. Mülhaupt, R.M. Waymouth, Macromol.
Chem. Phys. 197 (1996) 1071.
[7] J.C. Stevens, Stud. Surf. Sci. Catal. 101 (1996) 11.
[8] J.A.M. Canich, US Patent No. 5,026,798 (1991).
[9] J.A.M. Canich, G.F. Licciardi, US Patent No. 5,057,475
(1991).
[10] J.A.M. Canich, Eur. Pat. Appl. 0 420436 Al (1991).
[11] J.C. Stevens, F.J. Timmers, D.R. Wilson, G.F. Schmidt, N.P.
Nickias, R.K. Rosen, G.W. Knight, S.Y. Lai, Dow Chemical
Co., Eur. Pat. Appl. 0 416 815 (1991).