Synthesis and characterization of titanium alkyl, oxo, and diene complexes bearing a SiMe2-bridged phenoxy-cyclopentadienyl ligand and their catalytic performance for copolymerization of ethylene and 1-hexene

Article abstract of DOI:10.1016/j.jorganchem.2007.06.012

A series of titanium complexes bearing a SiMe₂-bridged phenoxy-cyclopentadienyl ligand were synthesized and characterized, and their catalytic behavior for copolymerization of ethylene and 1-hexene was investigated. Treatment of dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)(3-tert-butyl-5-methyl-2-phenoxy)-titanium dichloride (1) with appropriate nucleophiles afforded dimethoxy complex 2, dimethyl complex 3, and dibenzyl complex 4. Standing a toluene solution of 2 in air afforded a dinuclear μ-oxo complex 5 as a single isomer. 1,3-Diene complexes 6-8 were prepared by reaction of 1 with the corresponding 1,3-dienes in the presence of 2 equiv. of n-BuLi. X-ray analysis of 1,4-diphenyl-1,3-butadiene complex 6 revealed that the diene ligand coordinates to titanium in s-cis fashion with a prone orientation. The newly prepared titanium complexes were applied to copolymerization of ethylene and 1-hexene upon activation with AlⁱBu₃ and [C₆H₅NMe₂H][B(C₆F₅)₄]. It was found that the alkyl complexes 3-4 and the diene complexes 6-8 showed higher activities than 1 at elevated temperature.

Full text of DOI:10.1016/j.jorganchem.2007.06.012

Journal of Organometallic Chemistry 692 (2007) 4717–4724
www.elsevier.com/locate/jorganchem
Synthesis and characterization of titanium alkyl, oxo, and
diene complexes bearing a SiMe2-bridged
phenoxy-cyclopentadienyl ligand and their catalytic performance
for copolymerization of ethylene and 1-hexene
a
a
b
Hidenori Hanaoka , Takahiro Hino , Masaaki Nabika ,
c
c
a,
*
Tetsuya Kohno , Kazunori Yanagi , Yoshiaki Oda
,
b
d,
*
Akio Imai , Kazushi Mashima
a
c
Organic Synthesis Research Laboratory, Sumitomo Chemical Co. Ltd., 1-98, Kasugadenaka 3-chome, Konohana-ku,
Osaka 554-8558, Japan
b
Petrochemicals Research Laboratory, Sumitomo Chemical Co. Ltd., Kitasode, Sodegaura, Chiba 299-0295, Japan
Genomic Science Laboratories, Dainippon Sumitomo Pharma Co. Ltd., 1-98, Kasugadenaka 3-chome, Konohana-ku,
Osaka 554-0022, Japan
d
Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
Received 29 March 2007; received in revised form 29 May 2007; accepted 7 June 2007
Available online 15 June 2007
Dedicated to Professor G. Erker on the occasion of his 60th birthday.
Abstract
A series of titanium complexes bearing a SiMe2-bridged phenoxy-cyclopentadienyl ligand were synthesized and characterized, and
their catalytic behavior for copolymerization of ethylene and 1-hexene was investigated. Treatment of dimethylsilyl(2,3,4,5-tetramethyl-
cyclopentadienyl)(3-tert-butyl-5-methyl-2-phenoxy)-titanium dichloride (1) with appropriate nucleophiles afforded dimethoxy complex 2,
dimethyl complex 3, and dibenzyl complex 4. Standing a toluene solution of 2 in air afforded a dinuclear l-oxo complex 5 as a single
isomer. 1,3-Diene complexes 6–8 were prepared by reaction of 1 with the corresponding 1,3-dienes in the presence of 2 equiv. of n-BuLi.
X-ray analysis of 1,4-diphenyl-1,3-butadiene complex 6 revealed that the diene ligand coordinates to titanium in s-cis fashion with a
prone orientation. The newly prepared titanium complexes were applied to copolymerization of ethylene and 1-hexene upon activation
with AliBu3 and [C6H5NMe2H][B(C6F5)4]. It was found that the alkyl complexes 3–4 and the diene complexes 6–8 showed higher activ-
ities than 1 at elevated temperature.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Titanium complex; Cyclopentadiene; Phenolate; Diene; Polymerization
1. Introduction
ades because their homogeneous aspect enabled tunable
ligand design of catalysts for precise control of polymer
microstructure, copolymerization, and so on [1]. Among
the developed catalysts, bridged cyclopentadienyl amide
complexes (CGC: constrained geometry catalyst) [2] and
bridged phenoxy complexes (PHENICS: phenoxy-induced
complex of Sumitomo) [3] are two of the industrially
important catalyst systems that produced new unpredicted
elastomers starting from a-olefins.
Alkene polymerization catalyst systems based on metal-
locene and half-metallocene complexes of early transition
metals have attracted special interest in the past two dec-
*
Corresponding authors.
E-mail addresses: oday2@sc.sumitomo-chem.co.jp (Y. Oda), mashima@
chem.es.osaka-u.ac.jp (K. Mashima).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.06.012

4718
H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
Rm
Rm
M
R
R
Cl
Ti
Si
M
A
Cl
Cl
R-Li or R-MgBr (2 equiv.)
Et2O
Cl
A
O
O
1
N
R'
R'n
PHENICS
2 : R = OMe
3 : R = Me
4 : R = CH2Ph
CGC
Scheme 1.
Alkyl groups have been reported as novel leaving sub-
stituents, leading to smooth generation of active species.
Dimethyl and dibenzyl titanium complexes with
Me2Si(g5-C5Me4)(tBuN) ligand showed higher activities
than dichloro complex upon activation with borate cocata-
lyst [4]. 1,3-Butadiene derivatives are known to coordinate
to early transition metals in various orientations [5], and
diene ligand was readily activated to give catalytically
active species [6–9]. Erker reported that 1,3-butadiene
metallocene complexes readily reacted with B(C6F5)3 to
afford zwitterionic complexes which were applied to poly-
merization of a-olefin as well as detailed mechanistic study
of olefin polymerization [7]. Marks and his coworkers syn-
thesized a series of 1,3-butadiene CGC complexes in which
the orientation of the diene moieties (prone/supine) was
reported to depend on not only ligand architectures but
also bulkiness of diene ligand [8]. They also reported that
prone complex (A) showed high activity for copolymeriza-
tion of ethylene and 1-octene upon activation with
B(C6F5)3. We report herein synthesis of alkyl, diene and
methoxy derivatives of a SiMe2-bridged PHENICS 1 and
X-ray analyses of representative complexes. We also dem-
onstrate copolymerization behavior of ethylene and 1-hex-
ene using these newly prepared complexes.
Fig. 1. ORTEP drawing of the molecular structure of 4. All hydrogen
atoms are omitted for clarity. Key atoms are labeled.
selected bond parameters are summarized in Table 1. The
dibenzyl complex 4 adopts three-legged piano stool geom-
etry. Two angles of Ti–C–C(ipso) (112.13ꢁ and 130.0ꢁ) are
much different: one of two benzyl groups coordinates in an
g1-fashion to the titanium atom, while the other in an g2-
fashion in order to compensate the coordinative unsatura-
tion around the titanium atom Schemes 2–4.
The dimethoxy complex 2 is moisture sensitive, and
standing a toluene solution of 2 in air afforded a dinuclear
l-oxo complex 5 (76% yield), formed by hydrolysis of one
Cl
Ti
Si
Cl
Ti
Si
O
N
A
1
Table 1
˚
Selected bond length (A) and angles (ꢁ) for 4
˚
Bond lengths (A)
Ti(1)–C(30)
Ti(1)–O(1)
Ti(1)–C(15)
Ti(1)–C(17)
2.154(3) Ti(1)–C(23)
1.812(2) Ti(1)–C(14)
2.327(2) Ti(1)–C(16)
2.442(2) Ti(1)–C(18)
2.135(3)
2.287(2)
2.421(3)
2.384(2)
2. Results and discussion
Scheme 1 shows the synthesis of alkyl and methoxy tita-
nium complexes 2–4. A suspension of 1 in ether was treated
with a solution of 2 equiv. of a nucleophile such as MeOLi,
MeLi, or PhCH2MgBr in ether at ꢀ78 ꢁC. After removal of
inorganic materials at room temperature, crystallization
from hexane gave the corresponding complexes 2 (70%
yield), 3 (68% yield), and 4 (63% yield). Complexes 2–4
were characterized by NMR and elemental analysis. Struc-
ture of the dibenzyl complex 4 was further determined by
X-ray analysis. Fig. 1 shows an ORTEP diagram, and
Bond angles (ꢁ)
C(23)–Ti(1)–C(30)
O(1)–Ti(1)–C(30)
C(31)–C(30)–Ti(1)
O(1)–Ti(1)–C(15)
O(1)–Ti(1)–C(17)
C(1)–O(1)–Ti(1)
102.5(1)
O(1)–Ti(1)–C(23)
C(24)–C(23)-Ti(1)
O(1)–Ti(1)–C(14)
O(1)–Ti(1)–C(16)
O(1)–Ti(1)–C(18)
C(14)–Si(1)–C(2)
102.5(1)
102.2(1)
112.1(2)
89.83(9)
146.33(8)
150.3(2)
130.0(2)
90.80(9)
120.1(1)
123.9(1)
110.1(1)
Torsion angles (ꢁ)
C(14)–Si(1)–C(2)–C(1) ꢀ19.2(2)
Ti(1)–O(1)–C(1)–C(2)
11.8(5)

H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
4719
MeO
Ha
Ti
Ti
Hc
Hb
H2O (Air)
toluene
O
Si
Si
Ti
Ti
Si
Si
2
O
OMe
O
N
N
C
5
B
Scheme 2.
Scheme 4.
of the Ti–OMe bonds of 2. Further hydrolysis did not
occur in the reaction conditions. It is of interest that only
one isomer, cis or trans, was obtained as evident from
NMR analysis of 5. Crystallization of 5 from methanol
gave a single crystal suitable for X-ray analysis. An
ORTEP drawing is shown in Fig. 2 and selected bond
parameters are listed in Table 2. Two cyclopentadienyl
moieties are located as syn geometry and two methoxy
groups are placed as anti geometry. The torsion angles of
ligand architectures [C(9)–Si(1)–C(1)–C(2), ꢀ29.7(2)ꢁ;
C(32)–Si(2)–C(24)–C(25), ꢀ35.0(2)ꢁ] of 5 were larger than
the value observed for 2 (ꢀ19.2(2)ꢁ), clearly indicating that
the close position of the two ligands created a large strain
on 5.
1,3-Diene complexes 6–8 were synthesized by treating 1
with 2 equiv. of n-BuLi in the presence of the correspond-
ing dienes in hexane [8,10]. After removal of the inorganic
materials, recrystallization in hexane at ꢀ40 ꢁC afforded
the corresponding 1,3-diene complexes 6 (73% yield), 7
(52% yield), and 8 (34% yield). The lower yield of 8 was
attributed to high solubility of 8 in hexane. There are
two possible isomers (prone/supine) for s-cis diene com-
plexes 6–8, and their structures were characterized by
Fig. 2. ORTEP drawing of the molecular structure of 5. All hydrogen
atoms are omitted for clarity. Key atoms are labeled.
6.33). On the other hand, chemical shifts of Hb and Hc
for 8 were found at d 0.49 and 2.77, respectively, and
these values corresponded to those observed for C (d
0.04 and 2.84). It was assumed that bulkiness of the
two methyl groups at 2- and 3-positions of the diene moi-
ety of 8 would cause steric repulsion against the methyl
groups of tetramethylcyclopentadienyl moiety, and
accordingly the diene coordinates in a supine form to
the titanium atom.
1
1H NMR spectroscopy. Comparison of H NMR spectral
data obtained for these complexes with those reported for
Ti(butadiene)(Me4C5SiMe2NCMe3) (B and C) [11] sug-
gested that coordination modes of 1,4-diphenylbutadiene
of 6 and 2,5-hexadiene of 7 were prone, whereas that of
2,3-dimethyl-1,3-butadiene of 8 was revealed to be supine.
Complex B displayed diene protons Ha, Hb, and Hc at d
4.15, 1.71, and 3.01, respectively, whereas C showed these
protons at d 6.33, 0.04 and 2.84, respectively. Chemical
shifts of Ha observed for 6 and 7 (6: d 4.40, 7: d 3.83) cor-
responded to that of B (d 4.15) rather than that of C (d
A single crystal of 6 suitable for X-ray analysis was
obtained by recrystallization from hexane. Fig. 3 shows
an ORTEP drawing, and selected bond parameters are
R4
R3
R4
R3
Ti
R2
Ti
Si
Si
R4
R3
R1
O
O
R1
R2
R2
1
R1
n-BuLi (2 equiv.)
(prone)
(supine)
6 : R1, R4 = Ph, R2, R3 = H
7 : R1, R4 = Me, R2, R3 = H
8 : R1, R4 = H, R2, R3 = Me
Scheme 3.

4720
H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
Table 2
Table 3
˚
˚
Selected bond length (A) and angles (ꢁ) for 5
Selected bond length (A) and angles (ꢁ) for 6
˚
Bond lengths (A)
˚
Bond lengths (A)
Ti(1)–O(1)
Ti(1)–O(5)
Ti(2)–O(4)
Ti(1)–C(9)
Ti(1)–C(11)
Ti(1)–C(13)
Ti(2)–C(33)
Ti(2)–C(35)
1.846(2) Ti(1)–O(2)
1.829(2) Ti(2)–O(3)
1.798(2) Ti(2)–O(5)
2.322(3) Ti(1)–C(10)
2.402(3) Ti(1)–C(12)
2.377(3) Ti(2)–C(32)
2.380(3) Ti(2)–C(34)
2.436(3) Ti(2)–C(36)
1.800(2)
1.850(2)
1.829(2)
2.374(3)
2.432(3)
2.334(3)
2.405(3)
2.378(3)
Ti(1)–C(29)
Ti(1)–C(31)
Ti(1)–O(1)
Ti(1)–C(15)
Ti(1)–C(17)
C(29)–C(30)
C(31)–C(32)
2.216(2) Ti(1)–C(30)
2.324(2) Ti(1)–C(32)
1.874(2) Ti(1)–C(14)
2.310(2) Ti(1)–C(16)
2.452(2) Ti(1)–C(18)
1.411(3) C(30)–C(31)
1.419(3)
2.327(2)
2.244(2)
2.281(2)
2.408(2)
2.358(2)
1.402(3)
Bond angles (ꢁ)
C(29)–Ti(1)–C(32)
O(1)–Ti(1)–C(15)
O(1)–Ti(1)–C(17)
C(6)–O(1)–Ti(1)
O(1)–Ti(1)–C(29)
Bond angles (ꢁ)
Ti(1)–O(5)–Ti(2)
O(5)–Ti(1)–O(1)
O(4)–Ti(2)–O(3)
O(4)–Ti(2)–O(5)
O(1)–Ti(1)–C(10)
O(1)–Ti(1)–C(12)
O(3)–Ti(2)–C(32)
O(3)–Ti(2)–C(34)
O(3)–Ti(2)–C(36)
C(25)–O(3)–Ti(2)
C(32)–Si(2)–C(24)
87.48(8)
95.67(7)
147.57(7)
151.6(1)
93.83(7)
O(1)–Ti(1)–C(14)
89.37(7)
128.67(6)
118.60(7)
111.2(1)
159.4(1)
O(2)–Ti(1)–O(1)
102.7(1)
O(1)–Ti(1)–C(16)
O(1)–Ti(1)–C(18)
C(14)–Si(1)–C(1)
O(1)–Ti(1)–C(32)
103.91(8) O(2)–Ti(1)–O(5)
102.28(9) O(5)–Ti(2)–O(3)
104.09(9) O(1)–Ti(1)–C(9)
104.17(9)
103.16(9)
86.96(9)
99.8(1)
100.52(5)
119.0(1)
119.0(1)
87.2(1)
O(2)–Ti(1)–C(11)
O(1)–Ti(1)–C(13)
O(3)–Ti(2)–C(33)
O(3)–Ti(2)–C(35)
Torsion angles (ꢁ)
C(14)–Si(1)–C(1)–C(6)
88.1(1)
24.1(2)
Ti(1)–O(1)–C(6)–C(1) ꢀ3.8(3)
118.5(1)
121.1(1)
151.2(2)
108.6(1)
144.1(1)
89.90(9) C(2)–O(1)–Ti(1)
˚
adiene)(Me4C5SiMe2NCMe3) (0.112 A) [7]. The torsion
angle of the ligand architecture [24.1(2)ꢁ for C(14)–Si(1)–
C(1)–C(6)] was smaller than that found for 5.
150.3(2)
108.3(1)
C(9)–Si(1)–C(1)
Torsion angles (ꢁ)
C(9)–Si(1)–C(1)–C(2)
C(32)–Si(2)–C(24)–
C(25)
Newly prepared complexes 2–8 along with 1 were
applied as catalysts for copolymerization of ethylene and
1-hexene upon activation with AliBu3(TIBA) and
[C6H5NMe2H][B(C6F5)4](AB) at different temperatures
(40 and 130 ꢁC). Results are listed in Table 4. All com-
plexes showed similarly high activities at 40 ꢁC
ꢀ29.7(2)
ꢀ35.0(2)
Ti(1)–O(1)–C(2)–C(1)
Ti(2)–O(3)–C(25)–
C(24)
34.1(4)
35.1(4)
(>30 · 106 gmol(cat)ꢀ1 hꢀ1
) and gave high molecular
weight copolymer (entries 1–8) with similar 1-hexene con-
tent. Molecular weight distribution (Mw/Mn) was found
to be nearly 2.0, suggesting that single-site catalysts were
generated through the polymerization systems. Activity of
the dinuclear complex 5 was almost the same as that
observed for the mononuclear methoxy complex 2, suggest-
ing that the reaction of 5 with cocatalyst resulted in the for-
mation of the same mononuclear species (entries 2 and 5).
This result seems reasonable, because both complexes
[(C5H5)2ZrCl]2O and (C5H5)2ZrCl2 were reported to exhi-
bit similar catalytic performance upon activation with
MAO [12].
On the other hand, considerable differences among the
tested complexes were found in the case of polymeriza-
tion carried out at 130 ꢁC (entries 9–16). Activities of
the complexes were still high at the elevated temperature
(>5 · 106 gmol(cat)ꢀ1 hꢀ1). Alkyl complexes 3 and 4
(entries 11 and 12) and diene complexes 6–8 (entries
14–16) showed higher activities than the chloro complex
1 (entry 9). Much higher activities were found for 7
and 8 (40.9 · 106 and 41.9 · 106 gmol(cat)ꢀ1 hꢀ1, respec-
tively), indicating that their 1,3-diene ligands dissociated
readily under the reaction conditions to generate catalyt-
ically active species much faster and more effectively [7,8].
Worthy of note, the coordination mode (prone or supine)
of the diene did not affect polymerization behavior
(entries 15 and 16), indicating that both complexes gave
the same active species. 1,3-Diphenylbutadiene complex
6 showed lower activity than 7 and 8, indicating the
Fig. 3. ORTEP drawing of the molecular structure of 6. All hydrogen
atoms are omitted for clarity. Key atoms are labeled.
listed in Table 3. As expected from 1H NMR analysis of 6,
the 1,4-diphenylbutadiene ligand coordinates in s-cis-diene
fashion to the titanium atom with a prone orientation. The
two Ti–C(terminal) diene distances (2.216(2) and
˚
˚
2.244(2) A) differ by only 0.096 A from the two Ti–C(inter-
˚
nal) diene distances (2.324(2) and 2.327(2) A), indicating
that the diene moiety coordinates to the titanium atom
with little contribution of r2,p form. The value of the dif-
ference is slightly smaller than that found for Ti(2,5-hex-

H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
4721
Table 4
Copolymerization of ethylene and 1-hexene catalyzed by 1–8 upon activation with TIBA/ABa
Activityb
Mw
Mw/Mcn
1-Hexene contentd
c
Entry
Complex
Temperature (ꢁC)
Time (min)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
a
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
40
40
40
40
40
40
40
40
130
130
130
130
130
130
130
130
5
8
8
8
8
5
5
5
3
3
3
3
3
3
3
3
61.6
34.0
51.3
51.5
38.4
51.3
43.6
32.1
6.6
32.5
27.0
23.8
9.1
635000
610700
502400
543400
770200
734600
759700
801800
198200
230300
235800
252700
318800
197300
245000
246300
2.2
2.0
2.2
2.1
2.0
1.9
1.9
1.9
2.0
2.5
3.1
2.5
2.0
2.8
2.9
2.3
18
14
23
15
15
17
16
17
30
20
23
24
14
33
23
21
14.3
40.9
41.9
Conditions: toluene; 5 mL, 1-hexene; 60 lL (40 ꢁC) and 40 lL (130 ꢁC), ethylene; 0.6 MPa, complex; 0.1 lmol, TIBA; 40 lmol (40 ꢁC) and 4 lmol
(130 ꢁC), AB; 0.3 lmol.
b
In kg mmol(cat)ꢀ1 hꢀ1
.
c
Determined by GPC against polystyrene standards.
d
Number of methyl branches per 1000 carbon determined by FT-IR.
bulky diene ligand did not readily dissociate under the
polymerization conditions. Polymerization activity
observed for dinuclear complex 5 was lower than that
found for mononuclear methoxy complex 2 (entries 10
and 13), indicating that breakage of the Ti–O–Ti bond
sequence did not proceed smoothly at elevated tempera-
ture, resulting in a less reactive catalyst system. To con-
firm the efficiency of these new complexes, larger scale
copolymerization of ethylene and 1-hexene with 7 was
carried out in a 300 mL autoclave at 130 ꢁC. The poly-
merization gave similarly high molecular weight copoly-
mer (Mw = 366,900, Me branch = 26 per 1000 C) with
high activity (67.2 · 106 gmol(cat)ꢀ1 hꢀ1).
In conclusion, we prepared a series of PHENICS com-
plexes by ligand exchange reaction, characterized them by
X-ray analysis, and found that 1 was a novel starting mate-
rial for preparing the complexes. Polymerization studies
revealed that diene complexes 7 and 8 were useful precur-
sors for the copolymerization of ethylene and 1-hexene at
elevated temperature. More detailed polymerization behav-
ior of these complexes will be reported elsewhere.
on a JEOL AX-505W. Elemental analyses were performed
on an ELEMENTAR element analyzer at Sumika Chemi-
cal Analysis Service Ltd. All melting points were measured
in sealed tubes under nitrogen atmosphere and were not
corrected. Gel permeation chromatographic analyses were
carried out at 160 ꢁC using a Symyx RapidsGPCꢂ,
equipped with three PLgel 10MICRO METER MIXED-
B columns, and a Tosoh HLC-8121GPC/HT, equipped
with TSKgel GMHHR-H(S)HT. GPC columns were cali-
brated vs. commercially available polystyrene standards
(Polymer Laboratories).
3.2. Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)(3-
tert-butyl-5-methyl-2-phenoxy)-titanium dimethoxide (2)
To a mixture of methanol (0.32 g, 10 mmol) and diethyl
ether (40 mL) was added a 1.60 M solution of n-BuLi in
hexane (4.1 mL, 6.6 mmol) at 0 ꢁC. The reaction mixture
was warmed to room temperature, and stirred for 30 min.
Complex 1 (1.37 g, 3.0 mmol) was added to the reaction
mixture cooled to 0 ꢁC. After removal of the solvent, hex-
ane (100 mL) was added to the mixture, and then insoluble
materials were filtrated off. The solvent was removed and
the crude product was recrystallized from hexane to give
2 as a yellow solid (0.95 g, 70% yield). Mp: 116–117 ꢁC
3. Experimental
3.1. General
1
(dec). H NMR (CD2Cl2) d 0.46 (s, 6H, Si Me2), 1.34 (s,
All manipulations of air- and moisture-sensitive com-
pounds were carried out under dry nitrogen using a Braun
drybox or standard Schlenk line technique. Solvents were
purchased from Kanto Chemicals Co., Ltd. (anhydrous
grade) and stored in a drybox over molecular sieves. Com-
9H, t-Bu), 1.94 (s, 6H, C5Me4), 2.07 (s, 6H, C5Me4), 2.28
(s, 3H, Ar–Me), 4.09 (s, 6H, OMe), 7.05 (m, 2H, Ar–H);
13C{1H} NMR (CD2Cl2)d ꢀ0.2 (Si Me2), 10.5, 12.6, 20.4
(Ar–Me), 29.1 (Ar–CMe3), 34.3 (Ar–CMe3), 61.4 (OMe),
111.3, 126.4, 128.1, 128.5, 128.6, 130.4, 131.4, 135.5,
164.5. HRMS: m/z Calc. 450.5092, found 450.2086. Anal.
Calc. for C24H38O3SiTi: C, 63.98; H, 8.50. Found: C,
63.91; H, 8.53%.
1
plex 1 was prepared by a reported method [3a]. H NMR
(270 MHz) and 13C NMR (68 MHz) were measured on a
JEOL EX270 spectrometer. Mass spectra were recorded

4722
H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
3.3. Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)(3-
tert-butyl-5-methyl-2-phenoxy)-titanium dimethyl (3)
3.6. Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)
(3-tert-butyl-5-methyl-2-phenoxy)-titanium 1,4-
diphenylbutadiene (6)
To a mixture of 1 (2.30 g, 5.0 mmol) and diethyl ether
(40 mL) was added a 1.0 M solution of MeLi in diethyl
ether (10 mL) at ꢀ78 ꢁC. The reaction mixture was warmed
to room temperature, and stirred for 3 h. After removal of
the solvent, hexane (100 mL) was added to the mixture and
insoluble materials were filtrated off. The solvent was
removed and the crude product was recrystallized from
hexane to give 3 as a yellow solid (1.43 g, 68% yield).
To a mixture of 1 (1.38 g, 3.0 mmol), trans,trans-1,4-
diphenyl-1,3-butadiene (0.62 g, 3.0 mmol), and hexane
(150 mL) was added a 1.6 M solution of n-BuLi in hexane
(3.8 mL, 6.0 mmol) at ꢀ78 ꢁC. The reaction mixture was
warmed to room temperature, and stirred for 1 h. After-
wards, the mixture was heated to reflux for 1 h. After filtra-
tion of the insoluble materials, the solvent was removed
under reduced pressure. Recrystallization from hexane
gave 6 as a green solid (1.05 g, 73% yield). Mp: 126–
127 ꢁC (dec). 1H NMR (CD2Cl2)d 0.25 (s, 6H, SiMe2),
1.29 (s, 9H, t-Bu), 1.44 (s, 6H, C5Me4), 1.52 (s, 6H,
C5Me4), 2.30 (s, 3H, Ar–Me), 4.40 (m, 2H, diene), 4.70
(m, 2H, diene), 6.60–7.50 (m, 12H, Ar–H); 13C{1H}
NMR (CD2Cl2)d 0.1 (SiMe2), 10.7, 12.3, 22.0 (Ar–Me),
30.2 (Ar–CMe3), 37.0 (Ar–CMe3), 89.4, 105.0, 109.2,
123.7, 124.7, 127.5, 127.7, 128.4, 128.5, 136.7, 141.0,
166.9. Anal. Calc. for C38H46OSiTi: C, 76.74; H, 7.80.
Found: C, 76.98; H, 7.46%.
1
Mp: 136–137 ꢁC (dec). H NMR (CD2Cl2)d 0.33 (s, 6H,
SiMe2), 0.39 (s, 6H, TiMe2), 1.60 (s, 9H, t-Bu), 1.82 (s,
6H, C5Me4), 2.21 (s, 6H, C5Me4), 2.31 (s, 3H, Ar–Me),
7.01–7.05 (m, 1H, Ar–H), 7.13–7.18 (m, 2H, Ar–H);
13C{1H} NMR (CD2Cl2)d ꢀ0.1 (SiMe2), 11.5, 12.8, 20.4
(Ar–Me), 29.3 (Ar–CMe3), 34.5 (Ar–CMe3), 52.4 (Ti–
Me2), 108.6, 128.4, 128.9, 130.0, 130.1, 130.2, 132.0,
135.2, 163.4. Anal. Calc. for C24H38OSiTi: C, 68.88; H,
9.15. Found: C, 69.09; H, 8.75%.
3.4. Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)
(3-tert-butyl-5-methyl-2-phenoxy)-titanium dibenzyl (4)
3.7. Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)
(3-tert-butyl-5-methyl-2-phenoxy)-titanium 2,5-hexadiene
(7)
The same procedure as for 3 was followed except that
benzyl magnesium bromide, prepared from benzyl bromide
(1.71 g, 10 mmol) and magnesium (0.24 g, 10 mmol) in
diethyl ether (25 mL), was used in place of MeLi to give
4 as an orange solid (1.80 g, 63% yield). Mp: 109–110 ꢁC
The same procedure as for 6 was followed, except that
2,5-hexadiene (9.28 g, 9.0 mmol, a mixture of isomers)
was used in place trans,trans-1,4-diphenyl-1,3-butadiene
to give 7 as a green solid (0.73 g, 52% yield). Mp: 134–
136 ꢁC (dec). 1H NMR (CD2Cl2)d 0.51 (s, 6H, SiMe2),
1.29 (s, 9H, t-Bu), 1.50 (s, 6H, C5Me4), 1.86 (s, 6H,
C5Me4), 1.89 (d, J = 5 Hz, 6H, CH3–CH@CH–CH@CH–
CH3), 2.36 (s, 3 H, Ar–Me), 2.48 (m, 2H, diene), 3.83 (m,
2H, diene), 6.96–6.97 (m, 2H, Ar–H), 7.03–7.04 (m, 2H,
Ar–H); 13C{1H} NMR (CD2Cl2)d ꢀ0.1 (SiMe2), 10.7,
12.5, 17.1, 20.3 (Ar–Me), 28.9 (Ar–CMe3), 33.9 (Ar–
CMe3), 81.8, 110.8, 116.0, 120.8, 124.9, 127.7, 128.0,
128.2, 131.8, 136.3, 155.8 (ArC–O). HRMS: m/z Calcd
470.2484. Found: 470.2470. Anal. Calc. for C28H42OSiTi:
C, 71.46; H, 9.00. Found: C, 71.61; H, 9.07%.
1
(dec). H NMR (CD2Cl2)d 0.26 (s, 6H, SiMe2), 1.38 (s,
9H, t-Bu), 1.77 (s, 6H, C5Me4), 1.98 (s, 6H, C5Me4),
2.14–2.39 (m, 4H, CH2Ph · 2), 2.30 (s, 3H, Ar–Me),
6.77–6.90 (m, 5H, Ar–H), 6.98–7.09 (m, 5H, Ar–H),
7.12–7.16 (m, 1H, Ar–H); 13C{1H} NMR (CD2Cl2)d
ꢀ0.2 (SiMe2), 11.3, 12.7, 20.4 (Ar–Me), 29.7 (Ar–CMe3),
34.5 (Ar–CMe3), 82.5, 104.0, 121.9, 126.7, 127.5, 128.6,
130.1, 130.5, 130.7, 131.0, 132.4, 135.6, 148.5. Anal. Calc.
for C36H46OSiTi: C, 75.76; H, 8.12. Found: C, 75.98; H,
7.91%.
3.5. l-Oxo complex (5)
A solution of 2 (0.90 g, 2.0 mmol) and toluene (10 mL)
was stirred under air at room temperature for 20 h. After
removal of the solvent, recrystallization from methanol
gave 5 as a yellow solid (0.65 g, 76% yield). Mp: >250 ꢁC.
1H NMR (CD2Cl2)d 0.43 (s, 6H, SiMe · 2), 0.56 (s, 6H,
SiMe · 2), 1.02 (s, 18H, t-Bu), 1.61 (s, 6H, C5Me4), 2.10
(s, 6H, C5Me4), 2.17 (s, 6H, C5Me4), 2.23 (s, 6H, C5Me4
or Ar–Me), 2.24 (s, 6H, C5Me4 or Ar–Me), 4.04 (s, 6H,
OMe), 6.89 (d, 2H, J = 2 Hz, Ar–H), 6.96 (d, 2H,
J = 2 Hz, Ar–H); 13C{1H} NMR (CD2Cl2)d ꢀ1.3 (SiMe),
0.9 (SiMe), 10.8, 10.9, 11.6, 13.6, 20.4 (Ar–Me), 29.1
(Ar–CMe3), 34.0 (Ar–CMe3), 60.5, 111.5, 125.9, 126.2,
127.8, 127.9, 128.0, 130.0, 131.2, 132.0, 135.5, 165.8. Anal.
Calc. for C46H70O5Si2Ti2: C, 64.62; H, 8.25. Found: C,
64.60; H, 8.10%.
3.8. Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)
(3-tert-butyl-5-methyl-2-phenoxy)-titanium 2,3-
dimethylbutadiene (8)
The same procedure as for 6 was followed, except that
2,3-dimethyl-1,3-butadiene (9.28 g, 9.0 mmol) was used in
place trans,trans-1,4-diphenyl-1,3-butadiene to give 8 as a
1
purple solid(0.48 g, 34% yield). Mp: 128–130 ꢁC (dec). H
NMR (CD2Cl2)d 0.48 (s, 6H, SiMe2), 0.49 (d, J = 9 Hz,
2H, CHH=CHMe–CHMe=CHH), 1.03 (s, 9H, t-Bu),
1.69 (s, 6H), 1.89 (s, 6H), 2.03 (s, 6H), 2.36 (s, 3H, Ar–
Me), 2.77 (d, J = 9 Hz, 2H, CHH=CHMe–CHMe=CHH),
6.97–7.03 (m, 2H, Ar–H), 7.07–7.13 (m, 2H, Ar–H);
13C{1H} NMR (CD2Cl2)d ꢀ0.6 (SiMe2), 10.9, 12.8, 20.2

H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
4723
Table 5
Crystal data and data collection parameters for 4–6
4
5
6
Empirical formula
Formula weight
Crystal dimensions
Crystal system
C36H46OSiTi
570.74
0.2 · 0.1 · 0.1 mm
Triclinic
9.6435(7)
9.9040(6)
18.390(1)
79.442(4)
77.204(5)
73.478(4)
1628.4(2)
C46H70O5Si2Ti2
855.03
C38H46OSiTi
594.77
0.4 · 0.3 · 0.3 mm
Triclinic
11.8330(9)
11.8521(9)
12.6002(9)
101.967(5)
103.097(5)
99.170(5)
0.4 · 0.2 · 0.2 mm
Orthorhombic
19.0002(6)
20.5565(6)
24.7946(7)
90
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
90
3
˚
V (A )
9684.2(5)
Pbca (#61)
8
1.173
143.6
1643.8(2)
ꢀ
ꢀ
Space group
Z-value
Dcalc (g/cm3)
2hmax (ꢁ)
P1ð#2Þ
P2ð#2Þ
2
2
1.164
143.2
1.202
136.4
Number of reflections measured
Total: 19069
Unique: 5611
(Rint = 0.039)
Total: 95329
Unique: 9271
(Rint = 0.083)
Total: 18114
Unique: 5818
(Rint = 0.068)
Residuals: R (I > 2r(I))
Residuals: R (all refractions)
Goodness-of-fit indicator
0.0558
0.0606
1.071
0.0574
0.0671
1.077
0.0418
0.0507
1.085
(Ar–Me), 23.1, 29.2 (Ar–CMe3), 34.2 (Ar–CMe3), 74.7,
123.8, 125.3, 126.7, 128.1, 128.9, 129.7, 131.9, 132.0,
166.3 (ArC–O). HRMS: m/z calcd 470.2484, found
470.2488. Anal. Calc. for C28H42OSiTi: C, 71.46; H, 9.00.
Found: C, 71.76; H, 8.96%.
solution). Ethylene pressure in the cell and the temperature
setting were maintained by computer control until the end
of the polymerization experiment. The polymerization reac-
tions were allowed to continue until consumption of ethyl-
ene reached pre-set levels. After polymerization reaction,
the temperature was allowed to drop to room temperature
and the ethylene pressure in the cell was slowly vented.
The glass vial insert was then removed from the pressure cell
and the volatile components were removed using a centri-
fuge vacuum evaporator to give polymer product.
3.9. Crystallographic analyses of 4, 5 and 6
Crystals of 4–6 suitable for the X-ray diffraction study
were coated with paratone oil and mounted with nylon
loop in cold nitrogen gas, and intensity data were collected
at –180 ꢁC on a Rigaku RAXIS-RAPID Imaging Plate dif-
fractometer with graphite monochromated Cu Ka radia-
tion. The structure was solved by a direct method
(SHELX97) and refined by the full-matrix least-squares
method [13]. Crystal data and details of refinement are
summarized in Table 5. All calculations were performed
using the CrystalStructure crystallographic software pack-
age (Rigaku/MSC).
3.11. Copolymerization of ethylene with 1-hexene catalyzed
by 7 in 300 mL autoclave
An autoclave having an inner volume of 300 mL was
dried under vacuum and purged with nitrogen. The vessel
was then charged with toluene (150 mL) and 1-hexene
(1.2 mL), and then heated to 130 ꢁC. After ethylene was
introduced (0.6 MPa), TIBA (0.05 mmol, 0.25 M toluene
solution) was added. Subsequently, 7 (0.05 lmol, 1 mM
toluene solution) and AB (0.3 lmol, 6 mM toluene solu-
tion) were added. Polymerization was carried out at
130 ꢁC for 5 min, and the reaction was then quenched by
addition of methanol (5 mL). The reaction mixture was
then poured into acidic methanol (500 mL with 1 mL of
5% HCl). The polymer was collected by filtration, washed
with methanol, and then dried in a high vacuum oven at
80 ꢁC for 2 h to constant weight.
3.10. Copolymerization of ethylene with 1-hexene catalyzed
by 1–8 in 20 mL autoclave
A pre-weighed glass vial insert and disposable stirring
paddle were fitted to each reaction vessel of the reactor.
The reactor was then closed, and 0.25 M TIBA (160 lL),
1-hexene (60 lL; 40 ꢁC, 40 lL; 130 ꢁC) and toluene were
injected into each reaction vessel through a valve. The total
volume of reaction mixture was adjusted with toluene to
5 mL. The temperature was then set to the reaction temper-
ature, the stirring speed was set to 800 rpm, and the mixture
was pressurized to 0.6 MPa. Toluene solution of titanium
complex (0.1 lmol, 1 mM toluene solution) was added fol-
lowed by toluene solution of AB (0.3 lmol, 1 mM toluene
Appendix A. Supplementary material
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.jorganchem.
2007.06.012.

4724
H. Hanaoka et al. / Journal of Organometallic Chemistry 692 (2007) 4717–4724
(c) K. Mashima, S. Fujikawa, H. Urata, E. Tanaka, A. Nakamura,
References
J. Chem. Soc., Chem. Commun. (1994) 1623;
(d) K. Mashima, S. Fujikawa, A. Nakamura, J. Am. Chem. Soc. 115
(1993) 10990.
[1] (a) H.H. Brintzinger, D. Fischer, R. Mulhaupt, B. Rieger, R.M.
¨
Waymouth, Angew. Chem. Int. Ed. Engl. 34 (1995) 1143;
(b) A.L. McKnight, R.M. Waymouth, Chem. Rev. 98 (1998) 2587;
(c) G.W. Coates, Chem. Rev. 100 (2000) 1223;
(d) U. Siemeling, Chem. Rev. 100 (2000) 1495.
[2] (a) J.C. Stevens, F.J. Timmers, D.R. Wilson, G.F. Schmit, P.N.
Nickas, R.K. Rosen, G.W. Knight, S.Y. Lai, (Dow) Eur. Pat. Appl.
EP 416815, 1991;
(b) J.A.M. Canich, G.G. Hlatky, H.W. Turner (Exxon) PCT Appl.
WO 92/00333, 1992.
[3] (a) H. Katayama, M. Nabika, A. Imai, A. Miyashita, T. Watanabe,
H. Johohji, Y. Oda, H. Hanaoka, (Sumitomo) PCT Appl. WO 97/
03992, 1997;
[7] (a) G. Erker, Chem. Commun. (2003) 1469;
(b) G. Erker, Acc. Chem. Res. 34 (2001) 309;
(c) B. Temme, G. Erker, J. Karl, H. Luftmann, R. Fro¨hlich, S.
Kotila, Angew. Chem. Int. Ed. Engl. 34 (1995) 1755;
(d) M. Dahlmann, G. Erker, R. Fro¨hlich, O. Meyer, Organometallics
19 (2000) 2956;
(e) J. Karl, G. Erker, R. Fro¨hlich, J. Am. Chem. Soc. 119 (1997)
11165;
(f) J. Karl, G. Erker, R. Fro¨hlich, J. Organomet. Chem. 535 (1997)
59;
(g) J. Karl, G. Erker, J. Mol. Catal. A 128 (1998) 85;
(h) M. Dahlmann, G. Erker, M. Nissinen, R. Fro¨hlich, J. Am.
Chem. Soc. 121 (1999) 2820;
(b) A. Imai, A. Ogawa, T. Takei, T. Nishiyama, H. Johoji, MetCon
2000, vol. 8, 2000;
(c) A. Imai; H. Katayama, M. Nabika, T. Watanabe, MetCon 2001,
2001;
(d) A. Imai, H. Johoji, H. Hozumi, T. Nishiyama, MetCon 2002,
2002;
(i) J. Karl, M. Dahlmann, G. Erker, K. Bergander, J. Am. Chem.
Soc. 120 (1998) 5643;
(j) M. Dahlmann, G. Erker, K. Bergander, J. Am. Chem. Soc. 122
(2000) 7986.
[8] D.D. Devore, F.J. Timmers, D.L. Hasha, R.K. Rosen, T.J. Marks,
P.A. Deck, C.L. Stern, Organometallics 14 (1995) 3132.
[9] E. Y.-X. Chen, R.E. Campbell Jr., D.D. Devore, D.P. Green, B.
Link, J. Soto, D.R. Wilson, K.A. Abboud, J. Am. Chem. Soc. 126
(2004) 42.
[10] H. Yamamoto, H. Yasuda, K. Tatsumi, K. Lee, A. Nakamura, J.
Chen, Y. Kai, N. Kasai, Organometallics 8 (1989) 105.
[11] M. Dahlmann, J. Schottek, R. Fro¨hlich, D. Kunz, M. Nissinen, G.
Erker, G. Fink, R. Kleinschmidt, J. Chem. Soc., Dalton Trans.
(2000) 1881.
(e) T. Miyatake, The 15th International Symposium on Olefin
Methathesis and Related Chemistry, Kyoto, July 31–August 1, 2003.
[4] D. D. Devore, R. D. Mussell, J. C. Stevens, (Dow) U.S. Pat. Appl.
US 5372682, 1994.
[5] (a) H. Yasuda, K. Tatsumi, A. Nakamura, Acc. Chem. Res. 18
(1985) 120;
(b) G. Erker, C. Kruger, G. Muller, Adv. Organomet. Chem. 24
¨
¨
(1985) 1.
[6] (a) A. Nakamura, K. Mashima, J. Organomet. Chem. 689 (2004)
4552;
[12] P.G. Gassmann, M.R. Callstrom, J. Am. Chem. Soc. 109 (1987) 7875.
[13] G.M. Sheldrick, T.R. Schneider, Methods Enzymol. 277 (1997) 319.
(b) K. Mashima, S. Fujikawa, Y. Tanaka, H. Urata, T. Oshiki, E.
Tanaka, A. Nakamura, Organometallics 14 (1995) 2633;