Half-titanocence anilide complexes Cp′TiCl2[N(2,6-R 12C6H3)R2]: Synthesis, structures and catalytic properties for ethylene polymerization and copolymerization with 1-hexene

Article abstract of DOI:10.1002/ejic.201001299

A number of new half-sandwich titanium(IV) complexes of the type [Cp′TiCl₂{N(2,6-R¹₂C₆H ₃)R²}] [R¹ = iPr (1, 2, 4), Me (3, 5); R ² = Me (1, 3, 4, 5), Bn (2); Cp′ = Cp

Full text of DOI:10.1002/ejic.201001299

FULL PAPER
DOI: 10.1002/ejic.201001299
Half-Titanocence Anilide Complexes CpЈTiCl2[N(2,6-R1 C H3)R2]: Synthesis,
2 6
Structures and Catalytic Properties for Ethylene Polymerization and
Copolymerization with 1-Hexene
Kefeng Liu,[a] Qiaolin Wu,[a] Wei Gao,[a] Ying Mu,*[a] and Ling Ye[a]
Keywords: Titanium / Metallocenes / Polymerization / Copolymerization / Polyethylene
A number of new half-sandwich titanium(IV) complexes of
the type [CpЈTiCl2{N(2,6-R12C6H3)R2}] [R1 = iPr (1, 2, 4), Me
(3, 5); R2 = Me (1, 3, 4, 5), Bn (2); CpЈ = Cp (1, 2, 3), Cp* (4,
5)] have been synthesized by the reaction of [CpЈTiCl3] with
the lithium salts of the corresponding anilide in toluene or
diethyl ether. All titanium complexes were characterized by
1H and 13C NMR spectroscopy and elemental analyses. The
duced ultra-high-molecular-weight (Mη Ͼ 3ϫ106 gmol–1
,
viscosity-average molecular weight) polyethylene. The copo-
lymerization of ethylene with 1-hexene catalyzed by these
complexes in the presence of AliBu3/Ph3CB(C6F5)4 was also
investigated. Complexes 4 and 5 with the pentamethylcyclo-
pentadienyl ligand were found to show higher catalytic ac-
tivity in ethylene/1-hexene copolymerization and produced
molecular structures of complexes 1, 4, and 5 were deter- poly(ethylene-co-1-hexene)s with much higher molecular
mined by single-crystal X-ray diffraction analysis. When acti-
vated with AliBu3 and Ph3CB(C6F5)4, complexes 1–5 exhib-
ited reasonable catalytic activity in ethylene polymerization,
producing high- or ultra-high-molecular-weight polyethyl-
ene. It was found that complex 4 shows the highest catalytic
activity in ethylene polymerization and complexes 1–3 pro-
weights and co-monomer incorporation than their cyclopen-
tadienyl analogues 1–3 under similar conditions. The co-
monomer incorporation abilities of complexes 4 and 5 are rel-
atively high in comparison with other half-sandwich titanium
catalyst systems.
variety of co-monomers. The so-called PHENICS com-
plexes[17] (phenoxy-induced complex of Sumitomo) have
also been reported to be good catalysts in ethylene copoly-
merization with α-olefins. Nonbridged (cyclopentadienyl)-
(aryloxy)titanium catalyst systems[18] have also been sys-
tematically studied by Nomura and co-workers and been
found to show good catalytic activity and efficient co-
monomer incorporation in ethylene/α-olefin copolymeriza-
tion. Similar nonbridged half-sandwich catalysts, (cyclo-
pentadienyl)(amide)titanium complexes [CpЈTiCl2(NR1R2)]
(R1, R2 = alkyl)[19] and (cyclopentadienyl)(anilide)titanium
Introduction
Group 4 metallocene catalysts have attracted intense
interest in recent decades due to their unique properties and
advantages as olefin polymerization catalysts.[1–6] Much re-
search effort has been focused on the development of new
homogeneous metallocene catalysts for producing a variety
of high-performance polyolefin materials and understand-
ing the relationship between the structure and catalytic
properties of a given catalyst with respect to polymer chain
composition and architecture.[7–10] In particular, a large
number of new metallocene catalysts have been developed
for the copolymerization of ethylene with α-olefins,[11] cy-
cloolefins,[12] dienes,[13] and polar monomers.[14] Several
metallocenes are known to be good catalysts for the copoly-
merization of different olefins. The ansa-zirconocene com-
plex [Ph2C(Cp)(Flu)ZrCl2][15] in combination with
(Me2PhNH)[B(C6F5)4]/AliBu3 has been reported to pro-
duce ethylene/1-hexene random copolymers with high mo-
lecular weights. Constrained geometry titanium complexes
(CGC)[2,3,16] have been found to exhibit excellent catalytic
performance in the copolymerization of ethylene with a
complexes [CpЈTiCl2{N(2,6-R1 C6H3)R2}] (R1 = Me, R2 =
2
SiMe3 or SitBuMe2)[20] have also been synthesized and ex-
plored as catalysts for ethylene polymerization and copoly-
merization with 1-hexene. The results indicated that the (cy-
clopentadienyl)(anilide)titanium complexes exhibit ex-
tremely low catalytic activity and co-monomer incorpora-
tion ability in ethylene/1-hexene copolymerization upon ac-
tivation with methylaluminoxane (MAO). From a struc-
tural point of view, this type of catalyst may show similar
catalytic performance to the nonbridged (cyclopentadienyl)-
(aryloxy)titanium catalyst systems. In view of the very lim-
ited research carried out on this type of complex in olefin
polymerization, especially in ethylene/α-olefin copolymer-
ization, it is of interest to develop more titanium(IV) com-
plexes of this type with a less bulky anilide ligand and ex-
plore their catalytic performance in ethylene/α-olefin copo-
[a] State Key Laboratory for Supramolecular Structure and Mate-
rials, School of Chemistry, Jilin University,
2699 Qianjin Street, Changchun 130012, P. R. China
Fax: +86-431-85193421
E-mail: ymu@jlu.edu.cn
Eur. J. Inorg. Chem. 2011, 1901–1909
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1901

K. Liu, Q. Wu, W. Gao, Y. Mu, L. Ye
FULL PAPER
lymerization. We have recently synthesized a number of new (3), all the other complexes were synthesized in toluene at
titanium(IV) complexes of the type [CpЈTiCl2{N(2,6- 50 °C. It was found that both higher and lower reaction
R1 C6H3)R2}] [R1 = iPr (1, 2, 4), Me (3, 5); R2 = Me (1, 3, temperatures
led
to
lower
yields.
Complexes
2
4, 5), Bn (2); CpЈ = Cp (1, 2, 3), Cp* (4, 5)] and found [CpTiCl2{N(2,6-iPr2C6H3)Me}] (1) and [CpTiCl2{N(2,6-
that they show good catalytic activity in ethylene/1-hexene iPr2C6H3)Bn}] (2) with a Cp ligand can be obtained in
copolymerization and produce high-molecular-weight poly- higher yields than complexes [Cp*TiCl2{N(2,6-iPr2C6H3)-
(ethylene-co-1-hexene)s with high co-monomer incorpora- Me}] (4) and [Cp*TiCl2{N(2,6-Me2C6H3)Me}] (5) with a
tion. In this paper we report the synthesis and characteriza- Cp* ligand. To obtain complexes 4 and 5 in good yields, it
tion of these complexes and their catalytic performance in was necessary to perform the reaction of [Cp*TiCl3] with
ethylene polymerization and ethylene/1-hexene copolymer- 1.3 equiv. of LiLa or LiLc in toluene at 50 °C for about
ization.
20 h. A longer reaction time led to a decrease in the reac-
tion yield probably due to a gradual decomposition of these
complexes under the reaction conditions. It was difficult to
obtain complex 3 in reasonable yield in toluene. Fortu-
nately, the reaction of [CpTiCl3] with 1 equiv. of LiLc in
diethyl ether at room temperature gave complex 3 in a rela-
tively good yield. In addition, attempts to synthesize com-
plex [Cp*TiCl2{N(2,6-iPr2C6H3)Bn}] by the reaction of
[Cp*TiCl3] with LiLb in both toluene and diethyl ether were
unsuccessful. It was found that the reaction does not pro-
ceed at low temperatures whereas an unidentifiable poly-
meric product was formed at high temperatures.
Results and Discussion
Synthesis and Characterization of the New Complexes
The free ligands HN(2,6-R1 C6H3)Me [R1 = iPr (HLa),
Me (HLc)] were synthesized in high yields (Ͼ85%) from
2
the reaction of CH3I with the corresponding lithium 2,6-
R1 -anilide following a modified literature procedure[21] re-
2
ported for the preparation of N,NЈ-disilyl-o-phenylenediam-
ine. The lithium 2,6-R1 -anilide salts were obtained from
2
1
The new titanium complexes were characterized by H
the reaction of the corresponding 2,6-R1 -aniline with
2
and 13C NMR spectroscopy along with elemental analyses.
nBuLi. The free ligand HN(2,6-iPr2C6H3)Bn (HLb) was
synthesized in about 80% yield by a two-step procedure, a
condensation reaction of benzaldehyde with 2,6-diisopro-
pylaniline followed by reduction of the Schiff base formed
with LiAlH4. Complexes 1–5 were synthesized from the re-
1
The H NMR spectra of complexes 1, 2, and 4 show two
sets of doublets for the methyl protons of the iPr group in
ligand La or Lb and the 13C NMR spectra of these com-
plexes show two signals for the two methyl groups of the iPr
group, which indicates that the rotation of the 2,6-iPr2C6H3
group about the N–C bond is restricted in these com-
plexes,[22,23] in contrast to similar aryl oxide complexes
[CpЈTiCl2(O-2,6-iPr2C6H3)]; it has been reported that only
one doublet for the methyl protons of the iPr group is ob-
actions of LiN(2,6-R1 C6H3)R2 [R1 = iPr, R2 = Me (LiLa),
2
Bn (LiLb); R1 = Me, R2 = Me (LiLc)] with [CpЈTiCl3] (CpЈ
= Cp, Cp*) in moderate yields (45–61%; Scheme 1). With
the exception of complex [CpTiCl2{N(2,6-Me2C6H3)Me}]
1
served in the H NMR spectra of the aryl oxide complex-
es.[18a,24] In comparison with the corresponding signals of
the free ligand HLa, the signals observed for the methine
protons of the iPr group in complexes 1 and 4 are shifted
upfield from 3.33 to 2.83–2.89 ppm, whereas the signals of
the NCH3 protons in both complexes are significantly
shifted downfield from 2.79 to 3.95–4.18 ppm. Similar phe-
nomena were also observed for the corresponding signals
in complexes 2, 3, and 5. The resonance of the methylene
protons of the NCH2Ph group in complex 2 is even shifted
1
2 ppm downfield from 4.10 to 6.10 ppm. The H and 13C
NMR spectroscopic analyses of these complexes confirm
that the anilide ligand is attached to the titanium metal cen-
ter of these complexes.
Crystal Structures of Complexes 1, 4, and 5
The molecular structures of complexes 1, 4, and 5 were
determined by single-crystal X-ray diffraction analysis. The
ORTEP drawings of their molecular structures together
with data of selected bond lengths and angles are given in
Figures 1, 2, and 3, respectively. Complex 4 crystallizes with
four independent molecules in the unit cell. Because there
are slight differences in these molecules, only one molecular
Scheme 1. Synthesis of complexes 1–5.
1902
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Eur. J. Inorg. Chem. 2011, 1901–1909

Half-Titanocence Anilide Complexes CpЈTiCl2[N(2,6-R1 C6H3)R2]
2
Figure 3. Molecular structure of complex 5. Thermal ellipsoids are
shown at the 30% probability level. Hydrogen atoms have been
omitted for clarity. Selected bond lengths [Å] and angles [°]: Ti(1)–
N(1) 1.878(6), Ti(1)–Cp(cent) 2.053, Ti(1)–Cl(1) 2.284(3), Ti(1)–
Cl(2) 2.278(2), Cl(1)–Ti(1)–Cl(2) 102.74(10), N(1)–Ti(1)–Cl(1)
101.99(19), N(1)–Ti(1)–Cl(2) 102.21(18), C(11)–N(1)–Ti(1)
142.4(4), Cp(cent)–Ti(1)–Cl(1) 113.8, Cp(cent)–Ti(1)–Cl(2) 114.8,
Cp(cent)–Ti(1)–N(1) 119.3.
Figure 1. Molecular structure of complex 1. Thermal ellipsoids are
shown at the 30% probability level. Hydrogen atoms have been
omitted for clarity. Selected bond lengths [Å] and angles [°]: Ti(1)–
N(1) 1.867(3), Ti(1)–Cp(cent) 2.020, Ti(1)–Cl(1) 2.2754(12), Ti(1)–
Cl(2) 2.2751(12), Cl(1)–Ti(1)–Cl(2) 105.22(5), N(1)–Ti(1)–Cl(1)
103.21(8), N(1)–Ti(1)–Cl(2) 104.26(8), C(6)–N(1)–Ti(1) 141.4(2),
Cp(cent)–Ti(1)–Cl(1) 115.7, Cp(cent)–Ti(1)–Cl(2) 113.8, Cp(cent)–
Ti(1)–N(1) 113.4.
(1.898 Å).[20] The Ti–N distances in these complexes are all
shorter than the estimated value (2.02 Å) for a Ti–N single
bond according to Pauling’s covalent radii,[25] which dem-
onstrates that they have Ti=N double-bond character. The
average Ti–Cl distances in complexes 1 (2.275 Å), 4
(2.285 Å),
and
5
(2.281 Å)
are
similar to those reported for [(1,3-Me2C5H3){N-
(2,6-Me2C6H3)(SiMe3)}TiCl2] (2.266–2.277 Å).[20] The
CpЈ(cent)–Ti distance in complex 1 (2.020 Å) is shorter
than the corresponding values in complexes 4 (2.047 Å) and
5 (2.053 Å), which can be related to the steric effect of the
CpЈ ring. For the same reason, the Cp(cent)–Ti–N angle
in complex 1 (113.4°) is significantly smaller than those in
complexes 4 (119.5°) and 5 (119.3°). The Cl(1)–Ti–Cl(2) an-
gle in complex 5 (102.74°) is smaller than those in com-
plexes 1 (105.22°) and 4 (104.91°). It is clear that the larger
Cl(1)–Ti–Cl(2) angles in complexes 1 and 4 should be
mainly caused by the bulky Me(2,6-iPr2C6H3)N ligand. The
average value of the Cl–Ti–N angles in complex 1 (103.73°)
is slightly larger than those in complexes 4 (102.20°) and
5 (102.10°). Owing to the relatively large mutual repulsion
between the Cp* and Me(2,6-iPr2C6H3)N ligands, the Ti–
N–C(phenyl) angle in complex 4 (147.1°) is significantly
larger than those in complexes 1 (141.4°) and 5 (142.4°).
The Ti–N–C(phenyl) angles in these complexes are much
larger than the reported value for [(1,3-Me2C5H3){N(2,6-
Me2C6H3)(SiMe3)}TiCl2] (111.6°).[20] As mentioned above,
the aryl ring in the anilide ligand in these complexes is ne-
arly parallel to the CpЈ ring with the angle between the CpЈ
and aryl rings being 13.2, 4.0, and 9.8° for complexes 1, 4,
and 5, respectively.
Figure 2. Molecular structure of complex 4. Thermal ellipsoids are
shown at the 30% probability level. Hydrogen atoms have been
omitted for clarity. Selected bond lengths [Å] and angles [°]: Ti(1)–
N(1) 1.874(8), Ti(1)–Cp(cent) 2.047, Ti(1)–Cl(1) 2.285(3), Ti(1)–
Cl(2) 2.286(3), Cl(1)–Ti(1)–Cl(2) 104.91(12), N(1)–Ti(1)–Cl(1)
102.5(3), N(1)–Ti(1)–Cl(2) 101.9(3), C(11)–N(1)–Ti(1) 147.1(7),
Cp(cent)–Ti(1)–Cl(1) 113.1, Cp(cent)–Ti(1)–Cl(2) 113.2, Cp(cent)–
Ti(1)–N(1) 119.5.
structure is chosen for discussion. The structural analyses
reveal that complexes 1, 4, and 5 all have a pseudo-octahe-
dral coordination environment in their solid-state structures
and adopt a three-legged piano stool geometry with the ani-
lide N atom and the two Cl atoms being the three legs and
the Cp or Cp* ring being the seat. The aryl ring in the
anilide ligand in these complexes is almost parallel to the
Cp or Cp* ring with the N–Me group directed away from
the cyclopentadienyl ring. A symmetry plane consisting of
the Ti atom and the N and C atoms of the N–Me unit is
nearly perpendicular to the plane of the cyclopentadienyl
ring. The Ti–N distances of complexes 1 (1.867 Å), 4
Ethylene Polymerization
Ethylene polymerizations using complexes 1–5 as precat-
(1.874 Å), and 5 (1.878 Å) are shorter than that reported alysts under different conditions were examined and the re-
for [(1,3-Me2C5H3){N(2,6-Me2C6H3)(SiMe3)}TiCl2] sults are summarized in Table 1. When activated with
Eur. J. Inorg. Chem. 2011, 1901–1909
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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1903

K. Liu, Q. Wu, W. Gao, Y. Mu, L. Ye
Table 1. Data for the ethylene polymerizations catalyzed by the 1–6/AliBu3/Ph3CB(C6F5)4 and 4,5/MAO systems.[a]
FULL PAPER
[d]
Run
Catalyst
Temperature [°C] Al/Ti mol ratio
Yield [g]
Activity[b]
Mηϫ10–4[c]
Tm [°C]
1
2
3
4
5
6
7
8
1[e]
1[e]
2[e]
2[e]
3[e]
3[e]
4
20
35
20
35
20
35
20
35
50
35
35
20
35
35
35
35
35
35
35
200
200
200
200
200
200
200
200
200
300
400
200
200
300
200
2000
4000
2000
4000
0.316
0.330
0.340
0.354
0.220
0.231
0.926
0.987
0.635
0.846
0.797
0.903
0.962
0.928
0.805
0.370
0.424
0.307
0.344
316
330
340
354
220
371.5
105.5
383.5
138.8
325.4
103.3
94.1
70.6
55.9
83.5
68.3
96.8
82.1
58.4
50.6
60.4
57.6
49.3
45.4
137.9
136.5
137.7
136.9
136.8
136.4
138.9
138.1
139.0
139.5
140.1
139.3
139.0
137.9
137.8
137.2
137.4
136.8
137.1
231
1852
1974
1270
1692
1594
1806
1924
1856
1610
740
4
9
4
10
11
12
13
14
15
16[f]
17[f]
18[f]
19[f]
4
4
5
5
5
6
4
4
848
614
688
5
5
[a] Polymerization conditions: 70 mL toluene, 2ϫ10–6 mol catalyst, 1.5 B/Ti molar ratio, 15 min, 5 bar ethylene pressure. [b] Activity in
kg PE (molTi)–1 h–1. [c] Measured in decahydronaphthalene at 135 °C. [d] Determined by DSC at a heating rate of 10 °Cmin–1. The data
from the second scans have been used. [e] 4ϫ10–6 mol. [f] MAO was used instead of AliBu3/Ph3CB(C6F5)4 as co-catalyst.
MAO, complexes 4 and 5 showed relatively low catalytic of the polyethylenes produced by the Cp-based catalysts 1–
activity, which is in agreement with the results reported pre- 3 are much higher than those obtained with the bulky Cp*-
viously for similar complexes.[24,26] However, upon acti- based complexes 4 and 5. Usually, high-molecular-weight
vation with AliBu3 and Ph3CB(C6F5)4, complexes 1–5 all polyethylenes are produced by catalysts with bulky ligands
exhibited moderate catalytic activity in the ethylene polyme- due to the relatively large steric hindrance of the ligands in
rization reaction. Under similar conditions, the catalytic ac- the chain-transfer reaction.[28] The reason why the Cp-
tivity decreased in the order 4Ͼ5ϾϾ2Ͼ1Ͼ3, which indi- based catalysts 1–3 produce ultra-high-molecule-weight
cates that the catalytic activities of these complexes are sig- polyethylene (up to 380ϫ104 gmol–1) is not very clear. It is
nificantly influenced by the nature of the substituents on possible that the relatively strong interaction between the
both the CpЈ and anilide ligands. As is known for group 4 cationic catalyst and the anionic co-catalyst in these Cp-
metallocene catalysts, electron-donating substituents on the based catalyst systems means that the catalyst possesses a
ligands stabilize the catalytically active cationic species dur- bulky environment around the metal center and thus decel-
ing the polymerization and improve the catalytic activity of erates the chain-transfer reaction. Similar results have also
the catalyst,[24] which explains the above experimental re- been reported for other half-sandwich titanium(IV) catalyst
sults well. On the other hand, bulky CpЈ and anilide ligands systems.[26] The influence of the Al/Ti molar ratio and the
would weaken the interaction between the catalytically polymerization temperature on the polymer molecular
active cationic species and the anionic co-catalyst[27] and weight was also investigated. As expected, the molecular
therefore could increase the catalytic activity of the complex weight of the polyethylene obtained decreases with an in-
too, which is in agreement with the observed experimental crease in Al/Ti molar ratio and a rise in polymerization tem-
results. The fact that the catalytic activity of complex 2 with perature due to acceleration of both the chain-transfer reac-
a bulkier but less electron-donating Lb ligand is higher than tion to alkylaluminium and the β-hydride elimination reac-
the catalytic activity of complex 1 with a less bulky but tion. In addition, the melting temperature of the resultant
more electron-donating La ligand further demonstrates the polyethylene (136–141 °C) is in the normal range for linear
steric effects of the ligands. As observed in other olefin po- polyethylene.
lymerization catalyst systems, the catalytic activities of these
titanium catalyst systems are dependent on the Al/Ti molar
ratio. Maximal catalytic activities were obtained at Al/Ti
molar ratios of about 200. The catalytic activities of these
Copolymerization of Ethylene with 1-Hexene
catalyst systems were also examined at different polymeriza-
The copolymerization reactions of ethylene with 1-hex-
tion temperatures with the maximal values being observed ene using complexes 1–5 as catalysts activated with AliBu3/
at around 35 °C. These observations are similar to those Ph3CB(C6F5)4 or MAO (for complexes 4 and 5) were ex-
reported previously for related [CpЈTiCl2(NR1R2)] catalyst plored and the copolymerization results are summarized in
systems.[19] The molecular weight of the resultant polyethyl- Table 2. As reported previously for similar com-
ene was found to be remarkably dependent on the structure plexes,[19,24,26] when activated with MAO, complexes 4 and
of the catalyst. It is interesting that the molecular weights 5 both showed relatively low catalytic activity and co-
1904
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Eur. J. Inorg. Chem. 2011, 1901–1909

Half-Titanocence Anilide Complexes CpЈTiCl2[N(2,6-R1 C6H3)R2]
2
Table 2. Data for the ethylene/1-hexene copolymerization reactions catalyzed by the 1–6/AliBu3/Ph3CB(C6F5)4 and 4,5/MAO systems.[a]
[d]
Run
Catalyst
1-Hexene [molL–1]
Yield [g]
Activity[b]
1-Hexene content[c] [mol-%]
Mw ϫ10–4[d]
Mw/Mn
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
1[e]
1[e]
1[e]
2[e]
2[e]
2[e]
3[e]
3[e]
3[e]
4
0.5
1.0
1.5
0.5
1.0
1.5
0.5
1.0
1.5
0.5
1.0
1.5
0.5
1.0
1.5
1.0
1.0
1.0
1.0
1.0
0.135
0.163
0.142
0.145
0.174
0.152
0.092
0.110
0.072
1.682
2.331
1.804
0.778
1.358
0.805
1.046
trace
0.271
trace
0.225
135
163
142
145
174
152
92
6.0
7.8
9.7
6.4
8.4
10.0
5.4
7.0
16.09
15.37
15.72
16.25
12.22
10.42
13.51
11.52
10.04
26.33
20.00
20.14
22.50
20.45
17.45
10.10
–
3.61
3.35
3.41
3.68
3.75
3.62
3.57
3.46
3.53
2.42
2.20
2.55
3.36
3.33
3.31
4.63
–
110
72
8.7
3364
4662
3608
1556
2716
1610
2092
–
18.4
25.4
31.8
19.0
28.4
35.9
47.9
–
4
4
5
5
5
6
36[f]
37[g]
38[f]
39[g]
4
4
542
–
450
8.9
–
9.4
0.61
–
0.59
1.49
–
1.62
5
5
[a] Polymerization conditions: total 70 mL of toluene + 1-hexene, 2ϫ10–6 mol catalyst, 200 Al/Ti molar ratio, 1.5 B/Ti molar ratio,
15 min, 35 °C, 5 bar ethylene pressure. [b] Activity in kg polymer (mol Ti)–1 h–1. [c] Calculated based on 13C NMR spectra. [d] Measured
by GPC analysis. [e] 4 ϫ10–6 mol. [f] MAO was used as co-catalyst, 2000 Al/Ti molar ratio. [g] MAO was used as co-catalyst, 4000 Al/
Ti molar ratio.
monomer incorporation ability. However, upon activation bulky 1-hexene. Similar results have previously been ob-
with AliBu3/Ph3CB(C6F5)4 co-catalyst, complexes 1–5 all served in the ethylene/1-hexene copolymerization reaction
exhibited high catalytic activity and comonomer incorpora- with other half-sandwich titanium(IV) catalyst systems.[29]
tion ability for the copolymerization reaction. In addition, In addition, a co-monomer effect was clearly observed for
the MAO-activated systems produced copolymers with low the catalyst systems 4 and 5. As can be seen from Table 2,
molecular weights and narrow molecular weight distribu- the catalytic activities of complexes 4 and 5 in the copoly-
tions. The reason for the poor catalytic performances of the merization reaction increase with an increase in the 1-hex-
MAO-activated systems is not clear. The above-mentioned ene feed concentration and reach the maximal value with a
feature of producing copolymers with low co-monomer in- 1-hexene feed concentration of about 1.0 molL–1.
corporation, low molecular weights, and narrow molecular
weight distributions seems to indicate that the coordination by 13C NMR and GPC. The 13C NMR spectra of typical
environment around the metal center in the catalyst cation/ copolymer samples are shown in Figure 4. Based on the 13
The poly(ethylene-co-1-hexene)s obtained were analyzed
C
co-catalyst anion pair formed in the MAO-activated sys- NMR analysis,[30] the co-monomer contents of the poly-
tems is too bulky to catalyze the copolymerization reaction (ethylene-co-1-hexene)s were calculated and the data are
efficiently. In the AliBu3/Ph3CB(C6F5)4-activated systems, presented in Table 2. It can be seen from the data that the
the catalytic activities of these complexes in the ethylene/1- Cp*-based complexes 4 and 5 show remarkably higher co-
hexene copolymerization under similar conditions changes monomer incorporation ability than the Cp-based com-
in the same order as observed in the ethylene homopolyme- plexes 1–3 under the same conditions. A similar high co-
rization reaction: 4Ͼ5ϾϾ2Ͼ1Ͼ3. Note that the catalytic monomer incorporation ability of the Cp*-based complexes
activities of complexes 4 and 5 in the copolymerization re- has also been observed for the nonbridged (cyclopentadien-
action are significantly higher than those in the homopoly- yl)(aryloxy)titanium catalyst systems.[29a] In contrast to the
merization reaction whereas complexes 1–3 showed slightly high co-monomer incorporation ability of complexes 4 and
lower catalytic activity in the copolymerization than in the 5, the similar complex [Cp*TiCl2{N(2,6-Me2C6H3)-
homopolymerization reaction. Except for the electronic ef- (SiMe3)}] (6) has been reported to show very low co-mono-
fects discussed above for the ethylene homopolymerization, mer incorporation ability in the ethylene/1-hexene copoly-
it seems that the steric effect of the ligands in these com- merization when activated with MAO.[19a,20] To compare
plexes on their catalytic activity in the copolymerization re- the catalytic properties of these complexes under similar
action is clearly important. The relatively weak interaction conditions, the known complex 6 was synthesized according
between the cationic catalyst and the anionic co-catalyst[27] to a literature procedure[20] and the ethylene/1-hexene copo-
in the Cp*-based catalyst systems would favor the coordina- lymerization catalyzed with 6/AliBu3/Ph3CB(C6F5)4 catalyst
tion and insertion of the olefins, whereas the strong interac- system was investigated. The copolymerization results show
tion between the cationic catalyst and the anionic co-cata- that the co-monomer incorporation ability of complex 6 is
lyst in the Cp-based catalyst systems would slow down the very good (see Figure 5) and even higher than that of com-
coordination and insertion of the olefins, especially the plexes 4 and 5 under the same conditions, although its cata-
Eur. J. Inorg. Chem. 2011, 1901–1909
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1905

K. Liu, Q. Wu, W. Gao, Y. Mu, L. Ye
FULL PAPER
Figure 5. 13C NMR spectrum of a poly(ethylene-co-1-hexene) sam-
ple obtained with complex 6 (run 35).
co-1-hexene) samples estimated on the basis of 13C NMR
spectroscopy.[30] The calculated rErH values of 0.39–0.55 are
similar to those obtained in the nonbridged (cyclopen-
tadienyl)(aryloxy)titanium catalyst systems,[18b] which indi-
cates that 1-hexene incorporation in the present system does
not proceed in a random manner as observed in the con-
strained geometry catalyst systems.[31] GPC analysis re-
vealed that the poly(ethylene-co-1-hexene)s produced by
these catalysts possess relatively high molecular weights
(Mw = 10–26ϫ104 gmol–1). As reported previously for the
nonbridged (cyclopentadienyl)(aryloxy)titanium catalyst
systems,[18,32] the molecular weights of the copolymers are
clearly dependent on the structure of the catalyst and the
co-monomer content. The molecular weight distributions
are basically unimodal and narrow, a characteristic of me-
tallocene polyolefins.
Figure 4. 13C NMR spectra of poly(ethylene-co-1-hexene)s ob-
tained with (a) complex 2 (run 25); (b) complex 4 (run 31), and
(c) complex 5 (run 34) under similar polymerization conditions.
lytic activity is somewhat lower than those of 4 and 5. The
clearly higher co-monomer incorporation ability of the
6/AliBu3/Ph3CB(C6F5)4 catalyst system in comparison with
that of the 5/AliBu3/Ph3CB(C6F5)4 catalyst system indicates
Conclusions
A number of half-sandwich titanium(IV) complexes
that the co-monomer incorporation ability of these catalysts bearing an anilide ligand of general formula
could be further improved by changing the R2 group on the [CpЈTiCl2{N(2,6-R1 C6H3)R2}] have been synthesized in
2
anilide N atom. Table 3 summarizes the monomer sequence moderate yields from the reaction of [CpЈTiCl3] with the
distribution and the rErH values for typical poly(ethylene- corresponding lithium anilide (CpЈ = cyclopentadienyl and
Table 3. Monomer sequence distributions for poly(ethylene-co-1-hexene)s obtained with the 1–6/AliBu3/Ph3CB(C6F5)4 systems.[a]
[e]
Run Cat. 1-Hexene content
[mol-%][b]
Triads[c] [%]
Dyads[d] [%]
EH + HE
rErH
EEE EEH + HEE
HEH
EHE
EHH + HHE
HHH
EE
HH
22
25
28
29
31
34
35
1
2
3
4
4
5
6
9.7
10.0
8.7
18.4
31.8
35.9
47.9
76.3
76.4
79.3
61.0
31.3
26.6
10.3
8.5
8.5
6.6
0.8
trace
trace
1.4
6.2
3.0
14.4
14.0
14.1
26.8
30.1
35.9
41.5
trace
1.1
trace
0.8
7.7
10.2
21.0
trace
trace
trace
1.6
2.3
3.6
80.6
80.6
82.6
65.2
42.5
37.0
19.6
19.4
18.8
17.4
32.8
51.4
54.3
65.0
trace
0.6
trace
2.0
6.1
8.7
–
0.547
–
0.485
0.393
0.437
0.288
8.4
22.5
20.7
18.5
3.7
5.0
15.5
[a] Polymerization conditions: see Table 2. [b] 1-Hexene content in mol-% estimated on the basis of the 13C NMR spectra. [c] Calculated
by analysis of the 13C NMR spectra. [d] [EE] = [EEE] + ½[EEH + HEE], [EH + HE] = [HEH] + [EHE] + ½([EEH + HEE] + [HHE +
EHH]), [HH] = [HHH] + ½[HHE + EHH]. [e] rErH = 4[EE][HH]/[EH + HE]2.
1906
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Eur. J. Inorg. Chem. 2011, 1901–1909

Half-Titanocence Anilide Complexes CpЈTiCl2[N(2,6-R1 C6H3)R2]
2
3
3.33 [sept., JH,H = 6.9 Hz, 2 H, CH(CH3)2], 3.00 (s, 1 H, NH),
pentamethylcyclopentadienyl). These titanium complexes
3
1
were all characterized by H and 13C NMR spectroscopy,
2.79 (s, 3 H, NHCH3), 1.30 [d, JH,H = 6.9 Hz, 12 H, CH-
(CH3)2] ppm.
as well as by elemental analyses. The molecular structures
of complexes 1, 4, and 5 were confirmed by X-ray crystal-
lography. Upon activation with AliBu3/Ph3CB(C6F5)4, com-
plexes 1–5 exhibited moderate catalytic activity in ethylene
polymerization, producing high- or ultra-high-molecular-
weight polyethylene. Complexes 1–5 also showed good cata-
lytic activity in ethylene/1-hexene copolymerization in the
presence of AliBu3/Ph3CB(C6F5)4, producing high-molecu-
lar-weight poly(ethylene-co-1-hexene)s with moderate-to-
high co-monomer incorporation. The catalytic activities of
complexes 1–5 in both ethylene polymerization and ethyl-
ene/1-hexene copolymerization under similar conditions de-
crease in the order 4Ͼ5ϾϾ2Ͼ1Ͼ3. Complexes 4 and 5
with a pentamethylcyclopentadienyl ligand exhibit mark-
edly higher catalytic activity and co-monomer incorpora-
tion ability than complexes 1–3 with a less bulky cyclopen-
tadienyl ligand.
HN(2,6-iPr2C6H3)Bn (HLb): 2,6-Diisopropylaniline (5.00 mL,
26.5 mmol) and benzaldehyde (2.70 mL, 26.5 mmol) were dissolved
in methanol (20 mL). A catalytic amount of formic acid was added
to the mixture. Then the reaction mixture was stirred and heated
at reflux for 8 h. The mixture was then cooled to 0 °C to precipitate
the Schiff base product as a yellow powder, which was collected on
a frit, washed with cold methanol, and dried under vacuum to ob-
tain the pure product (6.31 g, 23.9 mmol, 90%). The Schiff base
was then dissolved in THF (50 mL). LiAlH4 (0.91 g, 24.0 mmol)
was slowly added to the solution at 0 °C. The mixture was warmed
to room temperature and stirred overnight. The reaction was
quenched with water (20 mL) and the insoluble solids were filtered
off. Further H2O (40 mL) was added to the filtrate and the product
was extracted with diethyl ether (50 mL). The organic phase was
separated, dried with anhydrous MgSO4, filtered, and concentrated
by distillation under reduced pressure to give the final product
(5.65 g, 21.3 mmol, 89%) as a white powder. 1H NMR (CDCl3,
300 MHz, 298 K): δ = 7.30–7.46 (m, 5 H, PhH), 7.10–7.18 (m, 3
3
H, ArH), 4.10 (s, 2 H, PhCH2), 3.33 [sept., JH,H = 4.2 Hz, 2 H,
3
CH(CH3)2], 1.25 [d, JH,H = 4.2 Hz, 12 H, CH(CH3)] ppm.
Experimental Section
HN(2,6-Me2C6H3)Me (HLc): HN(2,6-Me2C6H3)Me was synthe-
sized by using a procedure identical to that used for the synthesis
of HN(2,6-iPr2C6H3)Me with 2,6-dimethylaniline as the starting
material. The pure product was obtained as a yellowish oil in a
yield of 85%. 1H NMR (CDCl3, 300 MHz, 298 K): δ = 7.02 (d,
General: All manipulations involving air- and/or moisture-sensitive
compounds were carried out under nitrogen (ultra-high purity)
using either standard Schlenk or glove-box techniques. Toluene, di-
ethyl ether, THF, and n-hexane were distilled under nitrogen in the
presence of sodium and benzophenone. CH2Cl2 and 1-hexene were
3
3JH,H = 7.5 Hz, 2 H, ArH), 6.85 (t, JH,H = 7.5 Hz, 1 H, ArH),
3.03 (s, 1 H, NH), 2.81 (s, 3 H, NCH3), 2.32 (s, 6 H, PhCH3) ppm.
purified by distilling over calcium hydride before use. [CpTiCl3],
LiN(2,6-R1 C6H3)R2: The lithium salts of the anilide ligands,
[34]
[Cp*TiCl3],[33] and Ph3CB(C6F5)4
were prepared according to
2
LiN(2,6-R1 C6H3)R2, were prepared according to the following
2
literature procedures. Polymerization-grade ethylene was further
purified by passage through columns of 5 Å molecular sieves and
MnO. AliBu3, nBuLi, MAO, and TiCl4 were purchased from Ald-
typical procedure. A solution of nBuLi (1.60 m in n-hexane,
14.2 mL, 22.7 mmol) was slowly added to a solution of HN(2,6-
iPr2C6H3)Me (4.34 g, 22.7 mmol) in n-hexane (15 mL) at –20 °C. A
large amount of a white precipitate formed during the addition.
The reaction mixture was warmed to room temperature and stirred
for 4 h. The resultant precipitate was collected on a frit, washed
with cold n-hexane (2ϫ10 mL) and dried under vacuum to give
the pure product (3.09 g, 15.7 mmol, 69%).
1
rich or Acros. H and 13C NMR spectra were recorded by using a
Varian Mercury-300 NMR spectrometer. 13C NMR spectra of the
copolymers were recorded with a Varian Unity-400 NMR spec-
trometer at 125 °C with o-C6D4Cl2 as the solvent. The molecular
weights of the polyethylenes were measured in decahydronaph-
thalene at 135 °C by using a Ubbelohde viscometer according to
the equation [η] = 6.77ϫ10–4 Mη0.67. The molecular weights and
molecular-weight distributions of the copolymer samples were mea-
sured with a PL-GPC 220 instrument at 140 °C with 1,2,4-trichlo-
benzene as the solvent. The melting points of the polymers were
measured by differential scanning calorimetry (DSC) with a
NETZSCH DSC 204 instrument at a heating/cooling rate of
10 °Cmin–1 from 35 to 180 °C and the data from the second heating
scans were used.
[CpTiCl2{N(2,6-iPr2C6H3)Me}] (1): LiN(2,6-iPr2C6H3)Me (538 mg,
2.73 mmol) and [CpTiCl3] (598 mg, 2.73 mmol) were mixed in tolu-
ene (40 mL) at –78 °C. The reaction mixture was warmed to room
temperature first, then placed in an oil bath at 50 °C and stirred
for 15 h. The precipitate was filtered off and the filtrate was concen-
trated to leave a reddish residue. Recrystallization from CH2Cl2/n-
hexane gave pure 1 as orange crystals (622 mg, 1.66 mmol, 61%);
m.p. 123.8–126.0 °C. 1H NMR (CDCl3, 300 MHz, 298 K): δ =
7.18–7.32 (m, 3 H, ArH), 6.46 (s, 5 H, CpH), 4.18 (s, 3 H, NCH3),
HN(2,6-iPr2C6H3)Me (HLa): A solution of nBuLi (18.0 mL, 1.60 m
in n-hexane, 28.8 mmol) was added to a solution of 2,6-diisopro-
pylaniline (5.00 mL, 26.5 mmol) in n-hexane (40 mL) at –20 °C.
The reaction mixture was warmed to room temperature and stirred
for 3 h. The precipitate was collected on a frit and washed with
cold n-hexane. The obtained white lithium salt (4.62 g, 25.2 mmol)
was dissolved in diethyl ether (40 mL) and added to a solution of
CH3I (1.73 mL, 27.7 mmol) in diethyl ether (20 mL) at –20 °C. The
reaction mixture was warmed to room temperature and stirred
overnight. The reaction was then quenched with H2O (40 mL). The
organic phase was separated, dried with anhydrous MgSO4, fil-
tered, and concentrated by distillation under reduced pressure to
give the product (4.34 g, 23.2 mmol, 88%) as a yellowish oil. 1H
3
3
2.83 [sept., JH,H = 6.9 Hz, 2 H, CH(CH3)2], 1.36 [d, JH,H
=
3
6.9 Hz, 6 H, CH(CH3)2], 1.15 [d, JH,H = 6.9 Hz, 6 H, CH-
(CH3)2] ppm. 13C NMR (CDCl3, 75 MHz, 298 K): δ = 140.5, 127.4,
125.5, 124.3, 119.6, 48.2, 27.2, 26.5, 23.6 ppm. C18H25Cl2NTi
(374.19): calcd. C 57.78, H 6.73, N 3.74; found C 57.56, H 6.69, N
3.72.
[CpTiCl2{N(2,6-iPr2C6H3)Bn}] (2): Complex 2 was synthesized by
using a procedure identical to that used for the synthesis of com-
plex
1 with LiN(2,6-iPr2C6H3)Bn (740 mg, 2.71 mmol) and
[CpTiCl3] (594 mg, 2.71 mmol) as starting materials. Pure 2
(710 mg, 1.58 mmol, 58%) was obtained as orange crystals by
recrystallization from CH2Cl2/n-hexane; m.p. 116.9–120.0 °C. 1H
NMR (CDCl3, 300 MHz, 298 K): δ = 7.06–7.18 (m, 3 H, ArH), NMR (CDCl3, 300 MHz, 298 K): δ = 7.20–7.52 (m, 8 H, ArH),
Eur. J. Inorg. Chem. 2011, 1901–1909
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1907

K. Liu, Q. Wu, W. Gao, Y. Mu, L. Ye
FULL PAPER
6.70 (s, 5 H, CpH), 6.10 (s, 2 H, PhCH2), 2.82 [sept., JH,H
3
=
complex 1 with LiN(2,6-Me2C6H3)Me (371 mg, 2.63 mmol) and
6.6 Hz, 2 H, CH(CH3)2], 1.42 [d, JH,H = 6.6 Hz, 6 H, CH(CH3)2], [Cp*TiCl3] (584 mg, 2.02 mmol) as starting materials. Pure 5
3
3
0.71 [d, JH,H = 6.6 Hz, 6 H, CH(CH3)2] ppm. 13C NMR (CDCl3,
75 MHz, 298 K): δ = 141.7, 136.9, 131.2, 128.2, 128.1, 127.4, 124.4,
122.2, 120.2, 59.2, 27.4, 25.2, 24.6 ppm. C24H29Cl2NTi (450.29):
calcd. C 64.02, H 6.49, N 3.11; found C 64.34, H 6.54, N 3.06.
(388 mg, 0.91 mmol, 45%) was obtained as orange crystals by
recrystallization from CH2Cl2/n-hexane; m.p. 140.2–143.2 °C. 1H
NMR (CDCl3, 300 MHz, 298 K): δ = 7.00–7.18 (m, 3 H, ArH),
3.83 (s, 3 H, NCH3), 2.07 (s, 6 H, PhCH3), 1.95 (s, 15 H,
CpMe5) ppm. 13C NMR (CDCl3, 75 MHz, 298 K): δ = 155.1,
131.3, 130.3, 128.2, 125.9, 44.7, 17.5, 12.8 ppm. C19H27Cl2NTi
(388.22): calcd. C 58.79, H 7.01, N 3.61; found C 58.96, H 7.04, N
3.63.
[CpTiCl2{N(2,6-Me2C6H3)Me}]
(3):
LiN(2,6-Me2C6H3)Me
(385 mg, 2.73 mmol) and [CpTiCl3] (598 mg, 2.73 mmol) were
mixed in diethyl ether (40 mL) at –78 °C. The reaction mixture was
warmed to room temperature and stirred overnight. The solvent
was removed under reduced pressure and the residue was extracted
with toluene (20 mL). The extraction was concentrated to leave a
reddish residue. Recrystallization from CH2Cl2/n-hexane gave pure
3 as orange crystals (523 mg, 1.64 mmol, 60%); m.p. 100.5–
X-ray Structural Analysis of Complexes 1, 4, and 5: All measure-
ments were made with a Rigaku RAXIS-RAPID diffractometer
with Mo-Kα (λ = 0.71073 Å) radiation. The structures were solved
by direct methods[35] and refined by full-matrix least-squares on F2.
The non-hydrogen atoms were refined anisotropically and hydrogen
atoms were included in idealized positions. The pentamethylcyclo-
pentadienyl group of complex 5 was refined with occupancies of
0.582:0.418 due to rotational disorder. All calculations were per-
formed by using the SHELXTL crystallographic software pack-
ages.[36] Details of the crystallographic parameters, data collections,
and structure refinements are summarized in Table 4.
1
103.0 °C. H NMR (CDCl3, 300 MHz, 298 K): δ = 7.06–7.20 (m,
3 H, ArH), 6.39 (s, 5 H, CpH), 4.09 (s, 3 H, NCH3), 2.10 (s, 6 H,
PhCH3) ppm. 13C NMR (CDCl3, 75 MHz, 298 K): δ = 130.0,
129.5, 128.8, 126.5, 119.7, 46.0, 17.6 ppm. C14H17Cl2NTi (318.09):
calcd. C 52.87, H 5.39, N 4.40; found C 52.68, H 5.41, N 4.38.
[Cp*TiCl2{N(2,6-iPr2C6H3)Me}] (4): Complex 4 was synthesized by
using a procedure identical to that used for the synthesis of com-
plex
1
with LiN(2,6-iPr2C6H3)Me (513 mg, 2.60 mmol) and
CCDC-788037 (for 1), -788038 (for 4), and -788039 (for 5) contains
the supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[Cp*TiCl3] (579 mg, 2.00 mmol) as starting materials. Pure 4
(435 mg, 0.98 mmol, 49%) was obtained as orange crystals by
recrystallization from CH2Cl2/n-hexane; m.p. 204.0–207.0 °C. 1H
NMR (CDCl3, 300 MHz, 298 K): δ = 7.10–7.24 (m, 3 H, ArH),
Polymerization Reactions: The ethylene polymerization experiments
were carried out as follows. A dry 250 mL steel autoclave with a
magnetic stirrer was charged with toluene (60 mL), thermostatted
at the desired temperature, and saturated with ethylene (1.0 atm).
The polymerization reaction was started by the simultaneous ad-
dition of a mixture of catalyst and AliBu3 in toluene (5 mL) and a
solution of Ph3CB(C6F5)4 in toluene (5 mL). The vessel was pres-
surized to 5 atm with ethylene immediately and the pressure was
maintained by the continuous feeding of ethylene. The reaction
3
3.95 (s, 3 H, NCH3), 2.89 [sept., JH,H = 6.5 Hz, 2 H, CH(CH3)2],
3
2.01 (s, 15 H, CpMe5), 1.34 [d, JH,H = 6.5 Hz, 6 H, CH(CH3)2],
1.10 [d, JH,H = 6.5 Hz, 6 H, CH(CH3)2] ppm. 13C NMR (CDCl3,
3
75 MHz, 298 K): δ = 153.3, 142.6, 130.4, 126.7, 123.8, 46.7, 27.1,
27.0, 23.9, 13.1 ppm. C23H35Cl2NTi (444.32): calcd. C 62.18, H
7.94, N 3.15; found C 62.46, H 7.98, N 3.13.
[Cp*TiCl2{N(2,6-Me2C6H3)Me}] (5): Complex 5 was synthesized
by using a procedure identical to that used for the synthesis of
Table 4. Crystallographic parameters, data collection, and structure refinements for complexes 1, 4, and 5.
1
4
5
Formula
Mr
C18H25Cl2NTi
374.19
C23H35Cl2NTi
444.32
C19H27Cl2NTi
388.22
Wavelength [Å]
Crystal system
Space group
0.71073
monoclinic
C2/c
0.71073
monoclinic
P2(1)
0.71073
monoclinic
P21/n
a [Å]
b [Å]
c [Å]
α [°]
25.007(5)
10.881(2)
16.723(4)
90
8.5063(10)
33.296(4)
16.570(2)
90
8.1796(16)
27.742(6)
9.850(2)
90
β [°]
122.172(3)
90
3851.7(14)
8
91.411(2)
90
4691.6(10)
8
113.31(3)
90
2052.7(7)
4
γ [°]
V [Å3]
Z
F(000)
1568
1.291
0.718
0.11ϫ0.09ϫ0.08
1.92–26.02
10549
1888
1.258
0.601
0.24ϫ0.16ϫ0.12
1.37–25.08
24507
816
1.256
0.676
0.23ϫ0.19ϫ0.15
3.08–25.00
13092
Dc [gcm–3]
Absorption coefficient [mm–1]
Crystal size [mm]
θ range [°]
Reflections
Independent reflections
Rint
Data/restraints/parameters
GOF
3791
0.0534
3791/0/204
0.991
15398
0.0894
15398/19/1013
0.993
3260
0.0603
3260/295/284
1.059
R1, Rw [IϾ2σ(I)]
R1, Rw (all data)
Max., min. diff. peaks [eÅ–3]
0.0556, 0.1016
0.1074, 0.1220
0.333, –0.210
0.0846, 0.1237
0.1724, 0.1546
0.579, –0.419
0.0872, 0.2511
0.1308, 0.2886
0.719, –0.661
1908
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 1901–1909

Half-Titanocence Anilide Complexes CpЈTiCl2[N(2,6-R1 C6H3)R2]
2
nometallics 2009, 28, 3785–3792; g) T. Senda, H. Hanaoka, Y.
Okada, Y. Oda, H. Tsurugi, K. Mashima, Organometallics
2009, 28, 6915–6926.
mixture was stirred at the desired temperature for 15 min. The poly-
merization was then quenched by injecting ethanol acidified with
HCl (3 m). The polymer was collected by filtration, washed with
water and ethanol, and dried to a constant weight under vacuum.
For the ethylene/1-hexene copolymerization experiments, appropri-
ate amounts of 1-hexene were added in toluene.
[18] a) K. Nomura, N. Naga, M. Miki, K. Yanagi, A. Imai, Organo-
metallics 1998, 17, 2152–2154; b) K. Nomura, K. Oya, T. Kom-
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Acknowledgments
This work was supported by the National Natural Science Founda-
tion of China (NSFC) (grant numbers 21074043 and 20772044).
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Received: December 10, 2010
Published Online: March 8, 2011
Eur. J. Inorg. Chem. 2011, 1901–1909
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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