ω-Phenylalkyl substituted amido functionalized ansa half-sandwich complexes of titanium and zirconium and metallacycles thereof as catalyst precursors for homogeneous ethylene polymerization

Article abstract of DOI:10.1016/S0022-328X(01)00780-X

The preparation and characterization of ω-phenylalkyl substituted ansa half-sandwich dichloride complexes of titanium and zirconium is described. These complexes react with butyllithium to give metallacycles via a CH activation reaction on the ortho posit

Full text of DOI:10.1016/S0022-328X(01)00780-X

Journal of Organometallic Chemistry 628 (2001) 211–221
www.elsevier.nl/locate/jorganchem
v-Phenylalkyl substituted amido functionalized ansa half-sandwich
complexes of titanium and zirconium and metallacycles thereof as
catalyst precursors for homogeneous ethylene polymerization
Helmut G. Alt *, Alexander Reb, Kalipada Kundu 1
Laboratorium fu¨r Anorganische Chemie der Uni6ersita¨t Bayreuth, Postfach 10 12 51, D-95440 Bayreuth, Germany
Received 9 January 2001; accepted 1 March 2001
Abstract
The preparation and characterization of v-phenylalkyl substituted ansa half-sandwich dichloride complexes of titanium and
zirconium is described. These complexes react with butyllithium to give metallacycles via a CH activation reaction on the ortho
position of the phenyl group. All complexes were used as catalyst precursors for homogeneous ethylene polymerization. The effect
of the catalyst structure on the polyethylene properties is discussed. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Group 4 metals; ansa Half-sandwich complexes; Metallacycles; Ethylene polymerization; Homogeneous polymerization
1. Introduction
Metallocene complexes with v-phenyl functionalized
alkyl substituents have proven to be excellent catalyst
precursors [26–28]. Upon reaction with butyllithium
they can form metallacycles via C,H activation reac-
tions and increase their catalytic activity [29,30].
Because of this background our intention was to
prepare ansa half-sandwich complexes with v-phenyl-
alkyl substituents in order to investigate their reactivity
with butyllithium and to test their catalytic potential
for the polymerization of ethylene.
The electron balance of amido functionalized ansa
half-sandwich complexes of Group 4 metals can be
compared with the electron balance of metallocene
complexes if one of the aromatic ligands of the metal-
locene complex is able to undergo a ring slippage
reaction from h5 to h3 [1,2].
For instance:
2. Results and discussion
2.1. Synthesis of the ligand precursors
The functionalization of the aromatic system with an
v-phenylalkyl group is conducted as a salt elimination
Because of this situation the class of half-sandwich
complexes is gaining increasing interest as catalyst pre-
cursors for catalytic olefin polymerization [3–21]. Since
the preparation of the first bridged amido functional-
ized half-sandwich complex [22] carbon linked deriva-
tives have also been reported [23–25].
* Corresponding author. Tel.: +49-92-1552555; fax: +49-92-
1552157.
E-mail address: helmut.alt@uni-bayreuth.de (H.G. Alt).
1 Guest scientist from Jahangirnagar University, Dhaka,
Bangladesh.
Scheme 1. Substitution of indene with (CH2)nPh groups (n=1–3).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00780-X

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H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
Scheme 2. Preparation of a cyclopentadiene derivative with a CMe2Ph substituent. The corresponding indene derivative 5 was prepared in an
analogous manner.
Scheme 3. Synthesis of functionalized chlorodimethylsilane derivatives.
reaction [31–35] (Scheme 1). For a CMe2Ph substituent
a fulvene reaction is advantageous (Scheme 2).
Different from literature procedures, the linking of
the silyl substituent to the functionalized cyclopentadi-
ene or indene system is not conducted in non-polar
solvents but in diethyl ether [36] because of higher
yields (Scheme 3).
2.3. Synthesis of the metallacycles 24–26
The v-phenylalkyl functionalized ansa half-sandwich
complexes react with butyllithium to yield metallacycles
via a C,H activation reaction (Scheme 6).
The metallacycles 25 and 26 were obtained in the
same way:
In general, there are two methods to synthesize alkyl-
amine(dialkylsilyl) substituted 1-indene- and 1-cy-
clopentadiene derivatives.
If the path of the conventional method is pursued
[37], the desired ligand precursor is obtained by the
reaction of the chlorosilane compound with the lithium
salt of the corresponding amine. Here the chlorosilane
compound is mixed with an excess of amine in a polar
solvent (Scheme 4).
No metallacycle was obtained from compound 20. It is
assumed that one methylene group as a spacer unit is
not sufficient for the required ring closure to the metal.
The titanacycle 24 was formed despite the C1 spacer.
Presumably both space-demanding methyl groups in
exo position reduce the angle between the cyclopentadi-
enyl ring and the phenyl ring so far that a bond from
2.2. Synthesis of the ansa half-sandwich complexes
16–23
Amido functionalized ansa half-sandwich complexes
of titanium were synthesized in very high yields using
the method described in Scheme 5. In the first step the
ligand precursor is reacted with two equivalents of
n-butyllithium to form the dianion. Subsequently,
TiCl3·3THF is added and then PbCl2 is added as a mild
oxidation agent. Compared to the reaction of the
dilithiated ligand precursor with titanium tetrachloride
[38] this path prevents the formation of a sandwich
complex and gives higher yields [39,40].
The synthesis of the zirconium complexes proceeds in
the conventional manner [41]. The dilithiated ligand
precursor is reacted with the corresponding metal tetra-
chloride. Hereby the yields are lower compared with the
corresponding titanium complexes (Scheme 5).
Scheme 4. Synthesis of the ligand precursors.

H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
213
Scheme 5. Synthesis of the amido functionalized ansa half-sandwich complexes 16–23.
the metal to the carbon atom in ortho position of the
phenyl ring can be established without major ring
strain. Titanacycles with indenyl ligands were only ob-
tained in product mixtures with the corresponding
dichloride complexes.
l=32.1 ppm the singlet signal for the three homotopic
methyl carbon atoms of the tert-butyl group. The
diastereotopic carbon atoms 12 and 13 appear at l=
28.6 and 27.9 ppm, respectively, the carbon atoms of
the methyl groups 1 and 2 at l=0.0 and −0.5 ppm,
respectively (Fig. 2).
2.4. Characterization of the complexes
In the following the resonance signals of both the
metallacycle 24 and the corresponding complex 23 are
compared.
1H-, 13C- and 29Si-NMR spectroscopy were used to
characterize the ansa amido half-sandwich complexes
and the metallacycles. The data are listed in Section 3.
The 1H- and 13C-NMR spectra of two examples (23 and
24) are discussed.
The metallacycle exhibits significant changes in the
1H-NMR spectrum compared to the parent dichloride
compound. The relatively simple spin system for the
phenyl ring in 23 changes into an ABCD-spin system
for 24. Hereby both doublet signals for protons 10 and
13 are found at l=8.15 and 7.42 ppm, respectively.
The three virtual triplets of the cyclopentadienyl ring
appear at higher field; they are widely spread. The shift
difference of both diastereotopic methyl protons on the
C1-bridge to the phenyl ring is very small and the
resonances overlap with the signal of the nine methyl
1
In the H-NMR spectrum of compound 23 (Fig. 1)
the signals for the phenyl protons are detected at
l=7.21–7.08 ppm. At l=6.70, 6.40 and 6.15 ppm the
three virtual triplets appear that can be assigned to the
AMX spin system of the 1,3-substituted cyclopentadi-
enyl ring. The aliphatic region is marked with two
singlets for the diastereotopic methyl groups of the C1
spacer (l=1.78 and 1.76 ppm) and of the bridging
silicon atom spacer (l=0.27 and 0.24 ppm). The three
methyl groups of the tert-butyl group are homotopic
and form one singlet with a signal intensity of nine
protons at l=1.47 ppm.
1
protons 4 (confirmed by H-,13C 2D correlation NMR
In the J-modulated 13C-NMR spectrum of 23 all five
resonance signals with negative phase are attributed to
the quaternary carbon atoms 3, 10, 11, 14 and 17. The
CH resonances in the aryl area (positive phase) corre-
spond to the ring carbon atoms of the cyclopentadienyl
and the phenyl ring. The aliphatic area exhibits at
Scheme 6. Synthesis of amido half-sandwich metallacycles.

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H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
Fig. 1. 300.13 MHz 1H-NMR spectrum of 23 (25°C, C6D6).
Fig. 2. 67.94 MHz J-modulated 13C-NMR spectrum of 23 (25°C, C6D6); S=C6D6.
experiment). The signals for the three methylene pro-
tons 5–7 can be observed in the region of l=1.92–
0.99 ppm, the triplet for the terminal methyl group 8 at
l=0.83 ppm. The least-affected signals are the singlet
signals for the diastereotopic methyl groups on the
silicon atom. They are recorded at l=0.34 and 0.30
ppm (Fig. 3).
quaternary carbon atom is observed at l=191.1 ppm
which is attributed to the ring carbon 9. The neighbor-
ing quaternary carbon atom 14 is shifted downfield by
about 17 ppm to l=171.6 ppm. The signals for the
methylene groups of the butyl ligand exhibit their reso-
nances at l=86.7, 35.9 and 26.3 ppm. The resonance
for methyl group 8 is detected at l=30.2 ppm. The
two diastereotopic methyl groups 16 and 17 appear at
l=29.1 and 14.1 ppm, respectively. The chemical shifts
for the methyl groups of the tert-butyl group (4) and
the silicon atom (1,2) are hardly affected.
A closer examination of the J-modulated 13C-NMR
spectrum of metallacycle 24 (Fig. 4) reveals significant
differences when compared with the spectrum of the
dichloride compound 23. The signal of an additional

H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
215
2.5. Polymerization of ethylene
2.6. The effect of the catalyst structure on the
polyethylene properties (structure–properties
relationship)
The ansa half-sandwich complexes 16–23 and the
metallacycles 24–26 can be activated with methylalu-
moxane (MAO) and then be used for homogeneous
ethylene polymerization. Fig. 5 and Table 1 show the
activities of these catalysts and the molecular weights,
melting points, melting enthalpies and crystallinities of
the produced polyethylenes.
The effect of various substituents in ansa half-sand-
wich complexes [43–45] on the activity of these cata-
lysts has not been studied to the same extent as in the
case of metallocene complexes [46]. From Fig. 5 it
becomes obvious that alkyl substituents with a terminal
Fig. 3. 300.13 MHz 1H-NMR spectrum of 24 (25°C, C6D6); S=C6H6, E=spike.
Fig. 4. 75.47 MHz J-modulated 13C-NMR spectrum of 24 (25°C, C6D6). The signal for the quaternary carbon atom 9 at 191.1 ppm is
characteristic; S=C6D6.

216
H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
Fig. 5. Activities of the v-phenylalkyl substituted half-sandwich complexes in homogeneous ethylene polymerization.
Table 1
Polymerization data
Complex
Activity (g) PE/(mmol) M h
GPC
DSC
−1
b
Mw (g mol−1
)
)
HI
M.p. a (°C)
DHm (J g−1
)
h
(
(
Mn (g mol
(
16
17
18
19
20
21
22
23
24
25
26
958
766 800
647 400
ND c
1 184 000
1 211 000
669 000
521 600
752 100
178 000
161 900
4.31
4.00
134.3
142.6
ND c
142.0
142.8
142.1
142.0
133.7
136.1
141.0
141.1
93.7
166.5
32.3
57.4
3353
ND c
4790
6823
6841
10 490
1485
1203
2006
3374
55 130
21.47
6.20
3.42
3.48
34.07
90.2
31.1
47.8
53.9
54.6
17.7
21.9
48.7
51.4
195 400
195 400
149 900
22 070
138.7
156.2
158.5
51.4
63.4
141.1
149.0
d
(
Mw\1 100 000
1 003 000
336 500
242 100
2.98
3.56
863 300
a Maximum of the melting peak during the second heating course of the DSC.
b h=DHm/DH° with DH° =290 J g−1 [42].
m
m
c Not determined.
d New styra gel HT6E-GPC-column; molecular weight too high.
phenyl group increase the activity of the catalyst. This
could be due to a spacer effect that separates the bulky
MAO anion from the catalyst cation during the poly-
merization process. This effect has been studied with
ansa bis(fluorenyl) complexes [47]. The flexibility and
the volume of the spacers increase with the length of
these substituents.
Zirconium complexes with indenylidene ligands (20–
22) are more active than the analogous titanium deriva-
tives (16 and 17). The reason for this behavior could be
the longer lifetime of zirconium derivatives at elevated
temperatures. Surprisingly, the metallacycles 24–26
show a lower activity than the parent half-sandwich
dichloride complexes. In the corresponding metallocene
series the opposite behavior was observed [29,30]. It can
be speculated that the hypothetic cationic catalyst
molecule is too stable to allow fast ethylene insertion
reactions into the MꢀCphenylene bond during the poly-
merization process.
Principally one should keep in mind that a whole
series of parameters like ion–ion interactions, solvent,
temperature, cocatalyst, ethylene pressure contribute to
the kinetics of the polymerization reaction and thus
determine the activity. The individual influence of each
parameter, however, is unknown.
The polyethylenes obtained from the various homo-
geneous polymerization reactions all show high molecu-
lar weights and in some cases (19 and 23) high

H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
217
polydispersities (21.47 and 34.07). The high molecular
weight distributions indicate various active sites gener-
ated during the course of the polymerization. This
could be due to changes of the catalyst, interactions
(catalyst–cocatalyst) or generation of different hetero-
geneous active sites.
A high molecular weight of the obtained poly-
ethylene is not automatically accompanied by a high
melting point. Short- and long-chain branching can
reduce the viscosity of such a resin [48]. Further investi-
gations of these aspects are in progress.
Elmer auto system gas chromatograph with a flame
ionization detector (FID) and He as carrier gas (1
ml min−1).
Temperature program:
starting phase, 3 min at 50°C;
heating phase, 5°C min−1 (15 min);
plateau phase, 310°C (15 min).
3.4. Differential scanning calorimetry (DSC)
The melting points of the polymer samples were
determined using a Perkin–Elmer DSC-200 instrument.
In a typical run 3–5 mg each of the dried polymer was
fused into standard aluminum pans and measured using
the following temperature program: first heating phase
(20 K min−1) from 320 to 470 K, cooling phase (−50
3. Experimental
All experimental work was routinely carried out with
Schlenk technique. Dried and purified Ar was used as
inert gas. The solvents C6H5CH3, C5H12, Et2O and
THF were purified by distillation over Na–K alloy.
Et2O was additionally distilled over lithium aluminum
hydride. CH2Cl2 was dried with CaH2. Deuterated sol-
vents such as CDCl3 and C6D6 were dried over molecu-
lar sieves (300 pm), degassed and stored under inert gas
atmosphere.
K min−1
) to 320 K, second heating phase (10
K min−1) from 320 to 470 K. The peak maximum of
the second heating curve was indicated as the melting
point.
3.5. High-temperature gel permeation chromatography
(HT-GPC)
Prior to use commercial indene was distilled and
stored at −30°C. Cyclopentadiene was freshly distilled
from the dimer. Methylaluminoxane (MAO) was sup-
plied by Witco Company, Bergkamen, as 30% solution
in C6H5CH3. All the other starting materials were com-
mercially available and were used without further
purification.
The polymers were measured with a Waters HT-GPC
150C apparatus. Four successive columns filled with
cross-linked polystyrene were used for separation. The
pore diameters of the individual columns were 500,
,
1000, 10 000 and 100 000 A. For detection a RI Waters
401 refractometer was used. Degassed 1,2,4-
trichlorobenzene was the eluent (flow rate, 1 ml min−1).
The polymer samples were dissolved in boiling 1,2,4-
trichlorobenzene. The measurements were conducted at
150°C. The apparatus was calibrated with polystyrene.
3.1. NMR spectroscopy
The spectrometers JEOL FX 90Q and JNM-EX 270
E, and Bruker ARX 250, AC 300 and DRX 500 used
for recording the NMR spectra. The organometallic
compounds were prepared under Ar and measured at
25°C. The chemical shifts in 1H-NMR spectra are
referred to the residual proton signal of the solvent
(l=7.24 ppm for CDCl3, l=7.15 ppm for benzene)
and in 13C-NMR spectra to the solvent signal (d=77.0
ppm for CDCl3, l=128.0 ppm for C6D6). Me4Si (l=
0.0) was used as an external standard for 29Si-NMR
spectra.
3.6. Synthesis procedure for
1-(7,7-dimethylbenzyl)cyclopentadiene
6,6-Dimethylfulvene (or 6,6-dimethylbenzofulvene)
(20.0 mmol) was dissolved in 150 ml Et2O, mixed with
10.0 ml (20.0 mmol) phenyllithium (2 M solution in
cyclohexane–Et2O 70:30 wt%) at −78°C and the white
suspension was stirred for 4 h at room temperature
(r.t.). After filtration over Na2SO4 and removal of the
solvent the product was obtained in 90% yields.
3.2. Mass spectroscopy
3.7. General procedure for the synthesis of the
substituted cyclopentadienyl alkenyl methyl chlorosilane
deri6ati6es
The mass spectra were recorded with a Varian MAT
CH7 instrument, GC–MS with a Varian 3700 gas
chromatograph in combination with a Varian MAT
312 mass spectrometer.
At −78°C, 41.5 mmol (26.0 ml) n-butyllithium was
added slowly to 41.5 mmol substituted cyclopentadiene
in 150 ml Et2O. The reaction mixture was stirred for 8
h. Subsequently the solvent was removed in vacuo (10
Torr). The lithium salt was added in portions to 83
mmol alkenylmethyldichlorosilane in 200 ml Et2O at
3.3. Gas chromatography
Gas chromatograms were recorded using a Perkin–

218
H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
−78°C within 30 min. The mixture was stirred for 12
h. The suspension was filtered over Na2SO4, the solvent
was evaporated and the remaining yellow liquid was
distilled in vacuo. Yields: 59–80%.
phenylalkyl)methylchlorosilane (39.2 mmol) in 200 ml
C5H10 was mixed at 0°C with 98 mmol (10.3 ml)
tert-butylamine (2.5-fold excess). The solution was
stirred for 12 h. The hydrogen chloride was eliminated
by excess amine and precipitated as ammonium hydro-
chloride. The suspension was filtered, the solvent was
evaporated and the residue was distilled (see Table 3 for
NMR data).
3.8. General procedure for the synthesis of the organyl
substituted indene deri6ati6es 1–5
Indene (86 mmol) was dissolved in a mixture of 180
ml Et2O and 18 ml THF and cooled to −78°C. n-
Butyllithium (86 mmol) was added using a syringe and
the reaction mixture was stirred for 4 h at r.t. Subse-
quently 86 mmol of the corresponding bromide was
added dropwise at −78°C and stirred for 10 h. The
reaction mixture was hydrolyzed with 50 ml water, the
organic layer was filtered over Na2SO4 and the solvent
was evaporated. The crude product was distilled in
vacuo. The products were obtained in 85–90% yields.
3.11. General procedure for the synthesis of the indenyl
ligand precursors 11–15
The corresponding indenylchlorosilane compound
(80 mmol) was dissolved in 200 ml CH2Cl2 and 200
mmol tert-butylamine was added quickly. After stirring
for 12 h the hydrogen chloride was eliminated by excess
amine and precipitated as ammonium hydrochloride.
The solvent was removed and the residue was dissolved
in 200 ml C5H12. The suspension was filtered over
Na2SO4 and the solvent was reduced in volume. The
ligand precursors were obtained quantitatively as yel-
low to light red oils (see Table 3 for NMR data).
3.9. General procedure for the synthesis of the
substituted indenylchlorosilane deri6ati6es 6–9
The corresponding indene derivative (80 mmol) was
dissolved in 150 ml Et2O and cooled to −78°C. The
equimolar amount of n-butyllithium was added slowly
and the mixture was stirred for 4 h at r.t. Subsequently,
the lithium salt was added to the equimolar amount of
the dichlorodimethylsilane in 100 ml Et2O at −78°C
and the mixture was stirred for 12 h. The suspension
was filtered over Na2SO4 and the solvent was evapo-
rated. The product was obtained in 80–96% yields (see
Table 2 for NMR data).
3.12. General procedure for the synthesis of the amido
functionalized ansa half-sandwich titanium complexes
16–19 and 23
The corresponding ligand precursor (18 mmol) in
Et2O was added 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 r.t. The equimo-
lar amount of the dilithium salt solution of the ligand
was added slowly to 18 mmol (6.64 g) TiCl3·3THF in
100 ml Et2O at −78°C. The mixture was stirred for 10
h. For oxidation, the titanium(III) compound was
mixed with 18 mmol (4.99 g) PbCl2 at r.t. and the
reaction mixture was stirred for 30 min. The precipi-
3.10. Procedure for the synthesis of the
cyclopentadienyl ligand precursor 10
The corresponding substituted cyclopentadienyl(v-
Table 2
NMR data of the chlorosilane compounds 6–9 a
Compound 1H-NMR
13C-NMR
29Si-NMR
6
7
8
9
7.60 (d, 1H) [7.5], 7.40 (d, 1H) [7.5], 7.3 (m), 6.32 (s,
1H), 4.00 (s, 1H), 0.25 (s, 3H), 0.22 (s, 3H)
Cq: 144.5, 143.8, 143.2, 139.6; CH: 129.7, 128.9, 128.5, 27.8
126.3, 125.7, 124.6, 123.6, 119.9, 45.8; CH2: 34.6; CH3:
0.3, −0.4
7.73 (d, 1H) [7.5], 7.60 (d, 1H) [7.5], 7.44 (m), 6.46 (s,
1H), 3.76 (s, 1H), 3.13 (m, 4H), 0.31 (s, 3H), 0.29 (s,
3H)
Cq: 144.8, 143.8, 142.1; CH: 128.6, 128.5, 128.1, 128.0, 27.7
126.2, 125.9, 124.7, 123.7, 119.5, 45.8; CH2: 34.9, 29.7;
CH3: 0.3, −0.2
7.79 (d, 1H) [7.5], 7.62 (d, 1H) [7.5], 7.51 (m), 6.56 (s,
1H), 3.85 (s, 1H), 2,92 (m, 4H), 2.26 (m, 2H), 0.46 (s,
3H), 0.41 (s, 3H)
Cq: 145.0, 144.1, 143.8, 142.4; CH: 128.7, 128.6, 127.8, 27.7
126.0, 125.8, 124.6, 123.6, 119.5, 45.7; CH2: 36.0, 30.5,
27.5; CH3: 0.3, 0.0
7.74 (d, 1H) [7.5], 7.55 (d, 1H) [7.5], 7.49 (m), 7.40 (m), ND b
6.76 (s, 1H), 3.83 (s, 1H), 1.87 (s, 3H), 1.86 (s, 3H),
0.40 (s, 3H), 0.36 (s, 3H)
28.1
a In CDCl3 at 25°C.
b Not determined.

H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
219
Table 3
NMR data of the ligand precursors 11–15 a
Compound
1H-NMR
13C-NMR
29Si-NMR
11
7.65 (d, 1H) [7.4], 7.49 (d, 1H) [7.4], 7.46 (m), 7.37
Cq: 146.2, 144.4, 140.3, 140.1, 49.1; CH: 132.8, 131.1, −1.6
(m), 6.50 (s, 1H), 4.19 (s, 1H), 3.69 (s, 1H), 1.39 (s, 130.0, 128.9, 128.3, 126.0, 124.5, 123.8, 123.6, 123.1,
9H), 0.18 (s, 3H), 0.10 (s, 3H)
119.4, 49.6; CH2: 34.5; CH3: 33.9, 0.2, −0.7
12
13
14
15
(d, 1H) [7.3], 7.36 (d, 1H) [7.3], 7.25 (m), 7.20 (m),
6.30 (s, 1H) 2.94 (m, 2H), 1.59 (m, 2H), 1.09 (s,
9H), 0.1 (s, 3H), −0.17 (s, 3H)
Cq: 145.0, 143.2, 141.1, 139.2, 65.8; CH: 130.8, 128.4, −2.0
128.2, 125.9, 124.4, 124.6, 123.7, 118.8, 46.8; CH2:
35.0, 29.7; CH3: 32.4, −0.2, −0.9
7.84 (d, 1H) [7.7], 7.66 (d, 1H) [7.7], 7.55 (m), 7.48
(m), 6.67 (s, 1H), 3.79 (s, 1H), 2,99 (m, 4H), 2.34
(m, 2H), 1.50 (s, 9H), 0.28 (s, 3H), 0.22 (s, 3H)
Cq: 146.3, 144.9, 142.7, 141.5, 49.8. CH: 130.9, 128.8, −1.8
128.6, 126.0, 124.7, 124.0, 123.7, 123.4, 119.2, 49.8;
CH2: 36.2, 30.8, 27.6;CH3: 0.3, −0.5
7.67 (d, 1H) [7.4], 7.52 (d, 1H) [7.4], 7.48 (m), 7.33
(m), 6.57 (s, 1H), 3.23 (s, 3H), 3.10 (s, 3H), 1.34 (s,
9H), 0.17 (s, 3H), 0.08 (s, 3H)
ND b
−1.5
7.74 (d, 1H) [7.5], 7.47 (m), 7.40 (m), 7.30 (m), 7.26 Cq: 154.3, 149.7, 60.3, 49.5; CH: 134.3, 131.3, 128.8,
(m), 6.56 (s, 1H), 6.45 (s), 6.43 (s), 6.34 (m), 3.52 (s, 128.0, 126.4, 125.8, 125.552.5; CH2: 40.0; CH3: 33.7,
1H), 1.71 (s, 3H), 1.34 (s, 9H), 1.21 (s, 3H), 1.02 (s, 30.0, 29.8, 1.6, 0.9, 0.5, 0.2
3H), 0.31 (s, 3H), 0.19 (s, 3H), 0.13 (s, 3H)
−3.0,
−14.0,−14.1
a In CDCl3 at 25°C.
b Not determined.
tated elemental Pb and PbCl2 settled in the reaction
solution after stirring was stopped, the liquid was sepa-
rated using a cannula. The solvent was evaporated in
vacuo, the residue was dissolved in C5H12 and the
precipitated lithium salt was separated over a frit. After
removing the solvent, the complex was obtained as a
deep red to black solid. Yields: 65–95%. The complexes
were characterized by NMR spectroscopy (Table 4).
tionalized ansa half-sandwich complex (3 mmol) was
dissolved in 100 ml C6H5CH3 and mixed with 3.75 ml
(6.00 mmol) n-butyllithium at −78°C. The reaction
mixture was defrosted to r.t. within 6 h and stirred for
an additional 14 h. Subsequently, the reaction solution
was filtered over Na2SO4 and the solvent was evapo-
rated. The amido functionalized ansa half-sandwich
metallacycles were obtained as yellow to brown oils in
90% yields (see Table 4 for NMR data).
3.13. General procedure for the synthesis of the amido
functionalized ansa half-sandwich zirconium complexes
20–22
3.15. Polymerization reactions
The corresponding ligand precursor (18 mmol) in
Et2O was added 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 r.t. The equimolar
amount of ZrCl4 (4.19 g) was added and the reaction
solution was stirred for an additional 12 h. The preci-
pitated lithium chloride was filtered, Et2O was evapo-
rated in vacuo and the residue was dissolved in pen-
tane. The precipitating solid was filtered, the solvent
was reduced in volume to almost dryness and the
solution was stored at −78°C for 24 h. The complex
precipitated as a yellow–white solid and could be dried
in vacuo. Yields: 19–30%. The complexes were charac-
terized by NMR spectroscopy (Table 4).
The corresponding complex (10–15 mg) was dis-
solved in 50 ml C6H5CH3. A solution containing 1–3
mg complex was activated with MAO (30% in
C6H5CH3) (metal–Al=1:2500). The catalyst solution
was dissolved in 250 ml C5H12, charged to a 1 l Bu¨chi
laboratory autoclave and thermostated at 60°C. After
the inside temperature was calibrated to 60°C an ethyl-
ene pressure of 10 bar was applied and the mixture was
stirred for 1 h at 6092°C. The obtained polymer was
dried in vacuo. The polymerization results and the
physical data of the polymers are presented in Table 1.
Acknowledgements
3.14. General procedure for the synthesis of the amido
functionalized ansa half-sandwich metallacycles 24–26
We thank Phillips Petroleum Company (Bartlesville,
OK, USA) for the financial support and Witco com-
pany for a donation of methylaluminoxane.
The corresponding alkylaryl substituted amido func-

220
H.G. Alt et al. / Journal of Organometallic Chemistry 628 (2001) 211–221
Table 4
NMR data of the dichloride complexes and the metallacycles 16–26 a
Complex
1H-NMR
13C-NMR
29Si-NMR
16
7.64 (d, 1H) [8.5], 7.44 (d, 1H) [8.5], 7.17 (m), 7.11
(m), 7.09 (m), 7.06 (m), 6.35 (s, 1H), 5.53 (d, 1H)
[14.3], 4.29 (d, 1H) [14.3], 1.42 (s, 9H), 0.64 (s, 3H),
0.39 (s, 3H)
Cq: 139.7, 136.2, 135.9, 135.1, 97.0, 62.7; CH: 128.8,
128.5, 128.0, 128.1, 127.8, 127.4, 126.5, 124.6; CH2: 35.2;
CH3: 32.2, 2.9, 0.6
−19.9
17
18
7.65 (d, 1H) [8.5], 7.32 (d, 1H) [8.5], 7.22 (t, 1H) [8.5], Cq: 141.0, 137.1, 135.8, 135.0, 96.1, 62.6; CH: 128.6,
7.21 (m, 2H), 7.06 (t, 1H) [8.5], 7.04 (m, 3H), 6.23 (s, 128.5, 128.1, 127.8, 127.7, 127.3, 126.2, 124.6; CH2: 35.9,
1H), 3.32 (m, 2H), 2.93 (m, 2H), 1.41 (s, 9H), 0.64 (s, 31.1; CH3: 32.2, 2.9, 0.6
3H), 0.42 (s, 3H)
−20.1
−20.1
7.56 (d, 1H) [8.5], 7.48 (d, 1H) [8.5], 7.29 (m), 7.11
(m), 6.93 (m), 6.13 (s, 1H), 3.07 (m, 2H), 2.52 (m,
Cq: 141.8, 139.1, 137.2, 132.8, 97.8, 62.1; CH: 128.8,
128.3, 127.7, 127.2, 126.2, 126.0, 124.8, 116.1; CH2: 36.1,
2H), 1.87 (m, 2H), 1.33 (s, 9H), 0.57 (s, 3H), 0.37 (s, 31.8, 29.1; CH3: 32.5, 3.2, 0.9
3H)
19
20
7.69 (d, 1H) [8.5], 7.49 (d, 1H), [8.5], 7.27 (t, 1H),
7.24 (m), 7.07 (m), 6.87 (s, 1H), 1.40 (s, 9H), 0.69 (s, 137.1, 132.1, 128.1, 127.4, 127.2, 127.0, 126.3, 125.9,
3H), 0.52 (s, 3H), 0.11 (s, 3H), 0.04 (s, 3H)
Cq: 154.8, 149.7, 140.3, 127.7, 108.3, 80.0, 63.7; CH:
−21.3
−20.2
120.8; CH3: 32.1, 28.9, 27.8, −0.1, −0.5
7.77 (d, 1H) [8.5], 7.54 (d, 1H) [8.5], 7.34 (m, 1H),
7.23 (m, 1H), 7.16 (m, 5H), 6.50 (s, 1H), 4.50 [15.9],
Cq: 140.1, 134.2, 131.9, 127.1, 91.6, 57.1; CH: 128.8,
128.6, 128.3, 127.9, 127.3, 126.8, 125.9, 124.1; CH2: 34.4;
4.35 (s, 1H) [15.9], 1.47 (s, 9H), 0.77 (s, 3H), 0.51 (s, CH3: 33.1, 3.9, 1.8
3H)
21
22
7.69 (d, 1H) [8.5], 7.32 (d, 1H) [8.5], 7.21 (m), 7.19
(m), 7.09 (m), 7.04 (m), 6.30 (s, 1H), 3.25 (m, 2H),
2.84 (m), 1.34 (s, 9H), 0.68 (s, 3H), 0.46 (s, 3H)
Cq: 141.0, 138.4, 134.0, 131.6, 128.0, 56.8; CH: 128.6,
128.4, 127.7, 127.5, 127.1, 126.1, 125.7, 123.7; CH2: 36.2,
30.1; CH3: 33.5, 3.6, 1.6
−20.5
−20.5
7.70 (d, 1H) [8.5], 7.42 (d, 1H) [8.5], 7.25 (m, 2H),
7.20 (m, 5H), 6.36 (s, 1H), 2.91 (m, 2H), 2.57 (m,
Cq: 141.7, 134.1, 131.6, 128.8, 90.7, 56.8; CH: 128.4,
128.1, 127.7, 127.6, 126.0, 125.7, 125.4, 123.8; CH2: 35.7,
2H), 1.93 (m, 2H), 1.33 (s, 9H), 0.69 (s, 3H), 0.48 (s, 31.8, 27.7; CH3: 32.8, 3.7, 1.7
3H)
23
24
25
26
7.21 (d, 1H) [7.0], 7.19 (m, 1H), 7.17 (m, 1H), 7.12
(m, 2H), 7.09 (m, 2H), 7.01 (m, 1H), 6.70 (t, 1H),
6.40 (t, 1H), 6.15 (t, 1H), 1.78 (s, 3H), 1.76 (s, 3H),
1.47 (s, 9H), 0.27 (s, 3H), 0.24 (s, 3H)
Cq: 155.1, 149.4, 109.3, 64.0, 38.4; CH: 128.5, 128.3,
126.8, 126.3, 126.2, 121.1; CH3: 32.1, 28.6, 27.9, 0.0,
−0.5
−20.5
−19.3
21.1
8.15 (d, 1H) [8.5], 7.42 (d, 1H) [8.5], 7.19 (m), 7.04
(m), 6.97 (m, 1H), 6.29 (m, 1H), 5.97 (m, 1H), 2.10
(s, 3H), 1.99 (m), 1.60 (s, 9H), 1.54 (m), 0.99 (m),
0.83 (s, 3H), 0.34 (s, 3H), 0.30 (s, 3H)
Cq: 191.1, 171.6, 154.8, 106.6, 59.0, 43.7; CH: 132.3,
130.7, 129.3, 129.0, 126.5, 124.6, 123.8; CH2: 86.7, 35.9,
26.3; CH3: 30.5, 30.2, 29.1, 14.1, 1.4, 1.2
8.21 (d, 1H) [8.5], 7.81 (d, 1H) [8.5], 7.29 (m, 6H),
6.20 (s, 1H), 3.09 (m, 4H), 2.65 (m, 2H), 1.55 (s, 9H), 130.9, 129.6, 128.6, 126.3, 125.4, 124.8 124.1, 123.1,
1.39 (m, 2H), 1.21 (m, 2H), 1.67 (t, 3H), 0,80 (s, 3H), 119.2; CH2: 56.3, 49.1, 28.7, 26.7, 25.4; CH3: 34.1, 13.9,
Cq: 184.1, 182.3, 148.4, 140.8, 135.1, 89.9, 64.1; CH:
0.51 (s, 3H)
4.6, 2.7
7.72 (d, 1H) [8.4], 7.41 (d, 1H) [8.4], 7.24 (m, 6H),
Cq: 187.4, 184.0, 144.9, 138.4, 135.1, 90.2, 63.1; CH:
−22.5
6.43 (s, 1H), 2.95 (t, 2H), 2.66 (m, 2H), 1.92 (m, 2H), 129.1, 126.0, 125.5, 124.9, 124.3, 124.1, 123.8, 121.9,
1.46 (s, 9H), 1.28 (m, 2H), 1.17 (m, 4H), 1.14 (t, 3H), 119.2; CH2: 86.9, 60.1, 54.3, 35.4, 28.9, 26.3; CH3: 34.5,
0.81 (s, 3H), 0.62 (s, 3H)
13.9, 4.7, 2.6
a In C6D6 at 25°C.
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