Rational design of silicon-bridged fluorenyl-phenoxy group 4 metal complexes as catalysts for producing high molecular weight copolymers of ethylene and 1-hexene at elevated temperature

Article abstract of DOI:10.1021/ma902700v

For producing high molecular weight copolymers of ethylene and 1 -hexene, a series of silicon-bridged fluorenyl-phenoxy group 4 complexes R ₂Si(Flu)(3-^tBu-5-Me-2-C₆(H₂O) MCl₂ (4a: M = Ti; R = Me; Flu.

Full text of DOI:10.1021/ma902700v

Macromolecules 2010, 43, 2299–2306 2299
DOI: 10.1021/ma902700v
Rational Design of Silicon-Bridged Fluorenyl-Phenoxy Group 4 Metal
Complexes as Catalysts for Producing High Molecular Weight Copolymers
of Ethylene and 1-Hexene at Elevated Temperature
Taichi Senda,† Hidenori Hanaoka,*,† Shinya Nakahara,‡ Yoshiaki Oda,*,† Hayato Tsurugi,§
and Kazushi Mashima§
†Organic Synthesis Research Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugadenaka 3-chome,
Konohana-ku, Osaka 554-8558, Japan, ‡Petrochemicals Research Laboratory, Sumitomo Chemical Co., Ltd.,
2-1, Kitasode, Sodegaura, Chiba 299-0295, Japan, and §Department of Chemistry, Graduate School of
Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
Received December 8, 2009; Revised Manuscript Received January 18, 2010
ABSTRACT: For producing high molecular weight copolymers of ethylene and 1-hexene, a series of silicon-
bridged fluorenyl-phenoxy group 4 complexes R2Si(Flu)(3-tBu-5-Me-2-C6H2O)MCl2 (4a: M = Ti; R = Me;
Flu = fluoren-9-yl; 4b: M = Ti; R = Et; Flu = fluoren-9-yl; 4c: M = Ti; R = Me; Flu =2,7-tBu2-fluoren-9-yl;
4d: M = Ti; R = Et; Flu =2,7-tBu2-fluoren-9-yl; 8: M = Zr; R = Me; Flu =2,7-tBu2-fluoren-9-yl; 9: M = Hf;
R = Me; Flu =2,7-tBu2-fluoren-9-yl) were prepared by two methods. One was a reaction of MCl4 (M = Ti, Zr,
and Hf) with the dilithium salts generated by treating corresponding ligands 1a-d with nBuLi in the presence
of Et3N in toluene and the other used MCl2(NR02)2 (6a: M = Ti; R0 = Me, 6b: M = Zr; R0 = Et, 6c: M = Hf;
R0 = Me) instead of MCl4 followedbysuccessive chlorination withMe3SiCl. X-ray crystallographicstudy of4d
indicated that the cyclopentadienyl moiety of the fluorenyl ligand is bound to the titanium atom in a fashion
between η3 and η5. The newly prepared titanium complexes 4a-d exhibited high catalytic activities for
i
copolymerization of ethylene and 1-hexene in the presence of Bu3Al/[Me2NHPh][B(C6F5)4] and afforded
higher molecular weight copolymers than the parent tetramethyl-substituted cyclopentadienyl titanium
complex Me2Si(η5-C5Me4)(3-tBu-5-Me-2-C6H2O)TiCl2 (10). In particular, the active species generated from
complex 4d was thermally stable and exhibited high polymerization activities even at 210 °C and produced high
molecular weight copolymers with good 1-hexene content.
Introduction
(phenoxy-induced complex of Sumitomo) system,9 we found that
molecular weight of the polyolefins produced by titanium-based
Fluorene compounds have been widely investigated as alter-
natives to cyclopentadienyl moiety in group 4 metallocene chemis-
try.1 Particularly, symmetrically substituted fluorenyl moiety is
useful to synthesize Cs-symmetrical metallocene complexes, which
enable us to produce syndiotactic polyolefins by a mechanism of
stereocontrol consisting of a regularly alternating insertion of
olefins at the enantiotopic sites derived from the Cs-symmetry.2-4
Bridged fluorenyl-amido group 4 complexes, for which the
molecular structures were first characterized by Okuda as their
zirconium complexes, have also attracted great attention because
of their Cs-symmetric structure.5 The fluorenyl-amido systems
have been further investigated by Shiono6 and Razavi7 as their
titanium derivatives. Attractive features of these titanium com-
plexes include not only capability for production of syndiotactic
polymers but also the living nature of the polymerization of
propylene and 1-hexene, while the parent tetramethyl-substituted
cyclopentadienyl-amido titanium complex gives almost atactic
polymers accompanied by chain transfer reactions. The fluorenyl-
amido titanium catalyst systems are also applicable for (co)poly-
merization of bulky comonomer such as norbornene,8 indicating
that the ligand architecture possesses large coordination sites for
bulky comonomer insertion along with stereoselective coordina-
tion sites for syndiospecific polymerization of 1-olefins.
PHENICS (PHENICS-Ti) was efficiently controlled by the
bulkiness of the cyclopentadienyl moiety,9a the substituent at
the ortho position of the phenoxy group,9c and the choice of
substituents at the silicon bridge.9d These findings suggest that
steric protection around the active metal center and suppression
of 2,1-insertion of 1-olefins are crucial factors for the PHENICS
systems to produce high molecular weight copolymers; however,
largely open coordination sites of PHENICS systems present the
unavoidable problem of irregularity in the 1-olefin insertion. An
advantageous feature of PHENICS is that catalytically active
species are thermally stable at high temperature, though high-
temperature processes usually lower molecular weight of copo-
lymers due to chain termination. Thus, to develop catalyst
systems capable of achieving high catalytic activity and copoly-
mers of high molecular weight with high 1-olefin incorporation
upon polymerization operated at elevated temperature is a
challenging target.10
To attain this goal, we have been interested in the results
reported for silicon-bridged fluorenyl-amido catalyst systems.11
The stereoselectivity of 1-olefin insertion generated by the fluor-
enyl ligand architecture definitely contributes to regioselectivity
of 1-olefin insertion for PHENICS systems. Herein, we report the
syntheses and characterizations of a series of group 4 metal
complexes, PHENICS-M (M = Ti, Zr, Hf), bearing fluorenyl
ligands. To introduce a fluorenyl framework to the PHENICS
system, we have developed improved metalation reaction by use
of MCl2(NR02)2 (M = Ti, Zr, Hf; R0 = Me, Et) precursors.
In the course of our investigation on production of high
molecular weight polyolefins catalyzed by PHENICS
*To whom correspondence should be addressed. E-mail: hanaoka@
sc.sumitomo-chem.co.jp (H.H.), oday2@sc.sumitomo-chem.co.jp (Y.O.).
r 2010 American Chemical Society
Published on Web 02/08/2010
pubs.acs.org/Macromolecules

2300 Macromolecules, Vol. 43, No. 5, 2010
Senda et al.
Scheme 1
Among these newly prepared complexes, PHENICS-Ti with
sterically modified flurenyl systems are highly active even at
210 °C, maintaining high molecular weight copolymers (up
to Mw = 86000) with high 1-hexene content.
Results and Discussion
Synthesis of Silicon-Bridged Fluorenyl-Phenoxy Group 4
Complexes. Silicon-bridged fluorenyl-phenoxy ligands (1a-d)
were prepared by treatment of fluorene compounds (2a:
fluorene; 2b: 2,7-tBu2-fluorene) with nBuLi followed by reac-
tion with [2-(OCH2CHdCH2)-3-tBu-5-Me-C6H2]SiR2 Cl
2
(3a: R2 = Me; 3b: R2 = Et) (see Experimental Section). To
begin our studies, syntheses of corresponding silicon-bridged
fluorenyl-phenoxy titanium complexes 4a,b were tried fol-
lowing the previously described procedure for cyclopentadie-
nyl and indenyl complexes (Scheme 1, method A).9a The salt
metathesis route, however, generally afforded a complicated
mixture. It was difficult to isolate desired fluorenyl titanium
complexes 4a,b from the reaction mixture due to both low
yield and existence of significant amount of unknown bypro-
ducts.12 The reaction starting from 1c,d, in which bulky tBu
groups on the 2,7-position of fluorene aimed to improve the
crystallinity of the resulting complex and to hinder undesired
formation of spiro-metallocene, afforded corresponding tita-
nium complexes 4c,d in low isolated yields (12-24%). De-
tailed investigation of the reaction using 1c as a ligand
precursor revealed that an unexpected spiro compound 5
bearing fluorenyl-oxygen bond was formed along with 4c.
The structure of 5 was determined by X-ray crystallography
(Figure 1). Although the mechanism of generation of the
byproduct 5 was unclear, we concluded that strong Lewis
Figure 1. Molecular structure of 5. All hydrogen atoms are omitted
for clarity. Key atoms are labeled. Selected bond distances (A) and angles
(deg) are as follows: C(1)-O = 1.4550(18), C(22)-O = 1.3886(19),
C(22)-C(27)=1.397(2), C(27)-Si=1.8441(17), C(1)-Si=1.9432(17),
C(1)-O-C(22)=115.38(11), C(1)-Si-C(27)=89.90(7), O-C(1)-Si=
106.22(10), Cp0-Ph = 89.35.
˚
difficult due to high solubility toward solvents such as pen-
tane, successive chlorination of the reaction mixture by addi-
tion of excess amount of Me3SiCl (10 equiv) was conducted in
toluene to afford corresponding dichlorotitanium complex 4a
in good isolated yield (75% yield based on three steps
from 2a).16 Zirconium complex 8 (78% yield) and hafnium 9
(58% yield) were also prepared by a similar procedure, using
ZrCl2(NEt2)2 and HfCl2(NMe2)2 as metal sources.17
Crystal Structure. The structure of the fluorenyl complex
4d was determined by X-ray analysis. A single crystal
suitable for X-ray analysis was grown by slow evaporation
of toluene solution at room temperature. It was found that
there was 0.5 equiv of toluene in the crystal. Selected bond
lengths and angles of 4d are summarized in Table 1. The
crystal data and data collection parameters are provided in
Table S1 (see Supporting Information). Figure 2 shows the
crystal structure of 4d, which adopts a three-legged piano-
stool geometry. The bond distances of Ti-C(1), Ti-C(2),
Ti-C(3), Ti-C(4), and Ti-C(5) are found to lie in the range
n
acidity of TiCl4 and use of excess amounts of BuLi (2.25
equiv) and TiCl4 (1.50 equiv) hampered clean metalation
reaction.13 To avoid further reaction of produced dichloro-
titanium complex with unreacted dilithium salt or excess
nBuLi,14 it was found that use of TiCl2(NMe2)2 (6a)15 as a
titanium source (method B) significantly improved selectivity
of the reaction. Thus, treatment of 1a with nBuLi (2.25 equiv)
in the presence of Et3N (4.50 equiv) in toluene followed by
reaction with 6a (1.20 equiv) afforded the corresponding
diamidotitanium complex 7. Because isolation of 7 was
˚
of 2.246-2.487 A. The difference in bond length between

Article
Macromolecules, Vol. 43, No. 5, 2010 2301
Table 2. Copolymerization of Ethylene and 1-Hexenea
˚
Table 1. Selected Bond Lengths (A) and Angles (deg) for 4d
c
bond lengths
2.2632(15) Ti-Cl(2)
temp
(°C)
Mw
activityb (ꢀ104)
48.4
7.8
15.7
8.1
16.8
8.4
18.5
16.5
6.2
0.4
1.2
0.1
41.1
10.6
Mwc/
Mn
1-hexene
contentd
Ti-Cl(1)
2.2566(16)
entry
complex
Ti-C(1)
Ti-C(3)
Ti-C(5)
Ti-O
2.246(4)
2.487(4)
2.408(4)
1.771(3)
Ti-C(2)
Ti-C(4)
Ti-Cpcent
Si-C(1)
2.334(4)
2.470(4)
2.036
1
2
3
4
5
6
7
8
4a
70
130
70
130
70
130
70
130
70
130
70
130
70
26.7
29.6
38.7
34.3
58.4
36.6
73.6
44.1
2.0
1.8
1.6
2.0
1.6
2.2
1.8
2.1
2.1
19
16
20
17
20
16
17
17
4b
4c
4d
8
1.878(4)
bond angles
88.97(15) Cl(1)-Ti-Cl(2)
81.88 Cpcent-C(1)-Ti
torsion angles
Ti-O-C(11)-C(10) 13.9(8)
dihedral angle
66.03
a θ denotes the dihedral angle between the best plane of cyclopenta-
O-Ti-C(1)
C(1)-Cpcent-Ti
104.41(5)
64.70
C(1)-Si-C(10)-C(11) 29.3(4)
θa
9
1.8
14
n.d.e
11
10
11
12
13
14
n.d.e
112.0
n.d.e
23.6
25.4
n.d.e
27.0f
n.d.e
2.2
9
n.d.e
16
dienyl ring and that of phenyl ring carbons.
10
130
1.5
14
a All data except for 8 and 9 are average of two runs using a Symyx
PPR system. Conditions: toluene 5 mL (total volume), 1-hexene 50 μL
(70 °C) or 40 μL (130 °C), ethylene 0.6 MPa, complex 0.1 μmol, TIBA
40 μmol (70 °C) or 4 μmol (130 °C), AB 0.3 μmol, 20 min or until
consumption of ethylene reached preset levels. b In kg of copolymer/
[(mmol of complex) h]. c Determined by GPC with polystyrene stan-
3
dards. d Number of short chain branches per 1000 carbons determined
by FT-IR.18 e Not determined due to low yield. f Bimodal distribution
was observed.
in Table 2. All data listed in Table 2 are taken as the average
of two runs except for a single run each for complexes 8
and 9. Fluorenyl complexes of titanium 4a-d exhibited high
polymerization activity and moderate 1-hexene incorpora-
tion (up to SCB/1000C=20) (entries 1-8). The Mw values of
copolymer obtained by 4a-d were higher than those of 10.
The tendency of Mw values of the copolymer was influenced
by both 2,7-substituents of fluorenyl ligand and bridg-
ing structure. It was obvious that introduction of tBu
substituents on the 2,7-positions of fluorene enhanced Mw
of the copolymers and contributed to stability at 130 °C
(entries 1-4 vs 5-8). Our recent study on a series of tetra-
methyl-substituted cyclopentadienyl PHENICS through
investigation of regio- and stereochemistry of propylene
polymerization using various complexes with different brid-
ging structures revealed that Et2Si-bridged complex is one
of the best complexes to afford high Mw value,9d and the
same tendency was found for 4a-d. Copolymerization using
zirconium complex 8 at 70 °C gave low-Mw copolymer
(Mw=20 000) (entry 9). The results are comparable to those
obtained by zirconium complexes with bridged fluorenyl-
amido ligands.5c,7 Hafnium complex 9 also less active under
our tested conditions and gave high-Mw copolymer with
bimodal MWD at 70 °C (entry 11). Almost no polymers were
obtained using 8 or 9 at 130 °C (entries 10 and 12), indicating
the active species derived from 8 and 9 are unstable under
high temperature.
High-Temperature Copolymerization of Ethylene and 1-
Hexene. High-temperature tolerance is an important factor
for industrial use in terms of productivity of a commercial
process. To investigate the scale-up polymerization perfor-
mance of silicon-bridged fluorenyl-phenoxy complexes 4c,d
at elevated temperatures in detail, copolymerization experi-
ments of ethylene and 1-hexene were carried out under
modified polymerization conditions, and the results are
summarized in Table 3. These complexes were highly active
polymerization catalysts at 180 °C. Here again, the Et2Si-
bridged complex 4d gave higher Mw copolymer than the
Me2Si-bridged 4c (entries 1 vs 2). Content of 1-hexene in the
copolymer obtained from 4d increased when the amount of
1-hexene was increased, and it was found that the Mw value
of the copolymer given by 4d was still about 2 times higher
Figure 2. ORTEP drawing of 4d. All hydrogen atoms and solvent
molecule are omitted for clarity. Key atoms are labeled.
˚
Ti-C(1) and Ti-C(3) is 0.241 A, suggesting that the co-
ordination of cyclopentadienyl moiety of fluorenyl ligand to
titanium atom is contributed in somewhat of an η3-manner.
A similar finding was previously reported for the crystal
structure of bridged fluorenyl-amide complex Me2Si(Flu)-
(tBuN)TiMe2 (Flu=substituted fluoren-1-yl).6f,h The bond
angle C(1)-Cpcent-Ti of 4d (R = 81.88°) is close to the
corresponding angle of Me2Si(Flu)(tBuN)TiMe2 (Flu =
fluoren-1-yl: R = 79.20°; Flu = 2,7-tBu2-fluoren-1-yl: R =
77.11°; Flu =3,6-tBu2-fluoren-1-yl: R = 78.19°). The large
torsion angles of C(1)-Si-C(10)-C(11) (29.31°) and Ti-
O-C(11)-C(10) (13.87°) and the small dihedral angle (θ)
between the best plane of cyclopentadienyl ring carbons
and that of phenyl ring carbons (66.03°) indicate that 4d
has a vastly distorted bridging backbone. The highly twisted
structure is characteristic of Et2Si-bridged PHENICS and
is effective for controlling 2,1-insertion of 1-olefin (vide
infra).9d From the viewpoint of the coordination mode
tendency toward η3-fashion, the molecular structure of 4d
is similar to those of silicon-bridged dithiophene-fused cy-
clopentadienyl-phenoxy complexes.10
Copolymerization of Ethylene and 1-Hexene. Fluorenyl-
titanium complexes 4a-d, zirconium complex 8, hafnium
complex 9, and a tetramethyl-substituted cyclopentadienyl
complex Me2Si(η5-C5Me4)(3-tBu-5-Me-2-C6H2O)TiCl2 (10)
were preliminarily evaluated as catalyst precursors for co-
polymerization of ethylene and 1-hexene in the presence of
iBu3Al (TIBA) and [Me2NHPh][B(C6F5)4] (AB) at various
temperatures (70 and 130 °C) using a Symyx parallel pressure
reactor (PPR) system. Polymerization results are summarized

2302 Macromolecules, Vol. 43, No. 5, 2010
Table 3. High-Temperature Copolymerization of Ethylene and 1-Hexenea
Senda et al.
activityb
Mwc (ꢀ104)
Mw/Mn
1-hexene contentd
c
entry
complex
temp (°C)
yield (g)
1
2
4b
4d
4d
4d
4d
4d
10
180
180
180
180
210
210
180
2.96
3.39
3.20
2.60
1.45
1.40
2.75
177
204
192
156
87
9.9
13.8
12.0
10.0
8.6
1.8
2.1
2.0
1.9
2.1
2.3
2.1
22
23
27
31
20
34
32
3e
4f
5
6f
7g
84
165
5.9
6.3
a Conditions: toluene 185 mL, 1-hexene 15 mL, ethylene 2.5 MPa, complex 0.5 μmol, TIBA 0.3 mmol, AB 3.0 μmol, 2 min. b In kg of copolymer/
(mmol of Ti h). c Determined by GPC with polystyrene standards. d Numberof short chain branches per 1000 carbonsdetermined by FT-IR.18 e Toluene
3
180 mL, 1-hexene 20 mL. f Toluene 175 mL, 1-hexene 25 mL. g Cyclohexane 185 mL, 1-hexene 15 mL.
(site 1). The backside protection mechanism is provided only
by bridging ethyl substituents and is not observed in dimethyl-
substituted complexes. The bulky Bu substituents on the
t
fluorenyl 2,7-positions are also preferable for restricting 2,1-
insertion of 1-hexene. Tetramethyl-substituted cyclopenta-
dienyl complex 10 has relatively large coordination sites on
both sides (Figure 3b), resulting in frequent 2,1-insertion of
1-hexene leading to lower Mw. Another possibility of the
origin of high Mw observed for 4d is that conformation
leading to β-hydrogen elimination is unfavorable for the
fluorenyl-phenoxy ligand architecture.22 The observed Mw
values of copolymer from 4d are higher than those from
related dithiophene-fused cyclopentadienyl-phenoxy deri-
vatives,10 indicating steric protection of active metal center
t
by bulky Bu substituents is more important for producing
high-Mw copolymer of ethylene and 1-hexene. The results
are comparable to results observed in related carbon-bridged
metallocenes with fluorenyl and dithiophene-fused cyclo-
pentadienyl, where dithiophene-fused cyclopentadienyl
complex afforded lower syndiospecificity than the fluorenyl
analogue: the fluorenyl ligand system endows active species
with more stereoselective and regioselective coordination
Figure 3. Control of 2,1-insertion of 1-hexene by the size of vacant site
for coordination of (a) 4d and (b) 10.
sites.23
than that produced by parent tetramethyl-substituted cyclo-
pentadienyl complex 10 under the high 1-hexene conditions
(entries 3 and 4 vs 7). It is noteworthy that 4d showed
moderate polymerization activity even at 210 °C, while
maintaining high degree of Mw (entries 5 and 6).
Conclusion
We demonstrated that introduction of fluorene moieties to a
PHENICS-Ti system greatly increased the molecular weight of
the copolymers of ethylene and 1-hexene. On the basis of the
crystal structure analysis of 4d, we proposed that a design that
produces smaller vacant sites for coordination of 1-hexene is
quite important for producing high molecular weight copolymer.
In particular, the 2,7-tBu2-fluorenyl complex 4d exhibited the
highest Mw value in the copolymerization under elevated tem-
perature and was highly active even at 210 °C, while maintaining
a high degree of high molecular weight and high 1-hexene
content.
The distinct polymerization behavior observed in these
bridged fluorenyl-phenoxy titanium complexes, giving
high-Mw copolymer, is attributable to steric effects of the
fluorenyl ligands. The planar structure of fluorene moiety is
capable of protecting the active titanium center from the
upper side without hindering the approach of 1-hexene. The
protection by the planar structure is profitable to reduce
chain transfer to monomer19 and aluminum compound.20
The fluorenyl ligand architecture is also important for con-
trolling regiochemistry of 1-olefin insertion. The regioselec-
tive insertion is crucial for high Mw because 2,1-insertion
of 1-olefin tends to terminate the chain growth via a facile
β-hydride elimination.21 The ability to give high Mw may be
explained by the size of the vacant coordination site for
approaching monomers. A plausible mechanism for control-
ling 2,1-insertion is illustrated in Figure 3. Two coordination
sites of active species derived from 4d are differentiated due
to steric repulsion between bridging ethyl groups and fluor-
enyl moiety.9d The polymer main chain is probably situated
on the more open side during polymerization (site 1)
(Figure 3a). The highly twisted structure acts to keep the
small coordination site (site 2), which is effective for restric-
tion of 2,1-insertion. On the other hand, the methyl group
labeled C(36) shown in Figure 2 at the end position of
bridging moiety plays an important role in interrupting
1-hexene approach from behind of open coordination site
Experimental Section
General Procedures. All manipulations of air- and moisture-
sensitive materials were performed under dry nitrogen using
a glovebox or standard Schlenk line techniques. Solvents
(heptane, hexane, pentane, toluene, and THF) were purchased
from Kanto Chemical Co., Inc. (anhydrous grade), and used as
received. nBuLi was purchased from Kanto Chemical Co., Inc.
Fluorene (2a) and Me3SiCl were purchased from TCI (Tokyo
Chemical Industry Co., Ltd.). 2,7-Di-tert-butylfluorene (2b),
HfCl4, Hf(NMe2)4, and Ti(NMe2)4 were purchased from Sigma-
Aldrich. ZrCl4 and Et3N were purchased from Nacalai Tesque
Co., Inc. Zr(NEt2)4 was purchased from Strem Chemicals, Inc.
TiCl4 was purchased from Wako Pure Chemical Industries, Ltd.
iBu3Al (TIBA) (1 M in toluene) was purchased from Tosoh
Finechem. Co., Ltd. [Me2NHPh][B(C6F5)4] (AB) was purchased
from Asahi Glass Co., Ltd. Chlorosilane compounds 3a9a and
3b,9d TiCl2(NMe2)2 (6a),15 and titanium complex 109a were

Article
Macromolecules, Vol. 43, No. 5, 2010 2303
prepared by reported methods. H NMR (270 MHz) and 13C
NMR (68 MHz) were measured on a JEOL EX270 spectro-
meter. Chemical shifts for 1H and 13C NMR spectra were
referenced using internal solvent resonances and are reported
relative to tetramethylsilane. When toluene-d8 was used as the
solvent, the spectra were referenced to the resonance of the
residual solvent proton at δ 2.09 in the 1H NMR spectra.
Mass spectra were recorded on JEOL JMS-T100GC (EI) and
JMS-700 (FD) mass spectrometers. High-resolution mass spec-
tra were recorded using a JEOL JMS-T100GC mass spectro-
meter, and elemental analyses were performed using an
Elementar element analyzer at Sumika Chemical Analysis Ser-
vice, Ltd. All melting points were measured in sealed aluminum
pans under a nitrogen atmosphere by differential scanning
calorimetry (DSC) on a TA Instruments Q2000 at a heating
rate of 10 °C/min. Molecular weights (Mw and Mn) and mole-
cular weight distributions (Mw/Mn) were determined by high-
temperature gel permeation chromatography (GPC). GPC ana-
lyses were carried out at 160 °C using a Symyx Rapid GPC,
equipped with three Plgel 10 μm mixed-B columns, and a Tosoh
HLC-8121GPC/HT gel permeation chromatograph, equipped
with TSKgel GMHHR-H(S)HT mixed bed columns. GPC
columns were calibrated using commercially available polysty-
rene standards (Polymer Laboratories). FT-IR measurements
were performed on a Bruker Equinox 55 þ PIKE Mapp IR
spectrometer to determine 1-hexene content in the copolymer.
Synthesis of Zr(NEt2)Cl2 (6b) and HfCl2(NMe2)2 (6c). Zr-
Cl2(NEt2)2 (6b) and HfCl2(NMe2)2 (6c) were prepared accord-
ing to the literature for corresponding THF adducts by equi-
molar reactions of M(NR2)4 with MCl4 (M=Zr, Hf) in toluene,
respectively.17
17.1, 10.9, 4.0 Hz, 1H, OCH2CHdCH2), 6.89 (d, J = 2.3 Hz, 1H,
Ar-H), 7.04-7.40 (m, 7H), 7.81 (d, J = 7.6 Hz, 2H, Flu-H2).
13C NMR (CDCl3): δ 3.59 (Si-CH2CH3), 7.45 (Si-CH2CH3),
21.12 (Ar-Me), 31.27 (Ar-CMe3), 35.23 (Ar-CMe3), 40.73,
76.19 (OCH2), 115.88, 119.69, 124.53, 125.16, 125.78, 130.42,
130.53, 132.21, 133.61, 136.10, 140.69, 142.08, 145.84, 161.84.
FD-MS: m/z 454 (Mþ). Anal. Calcd for C31H38OSi: C, 81.88; H,
8.42. Found: C, 81.53; H, 8.38.
(2-Allyloxy-3-tert-butyl-5-methylphenyl)(2,7-di-tert-butylfluo-
ren-9-yl)dimethylsilane (1c). Mp: 80-83 °C (dec). 1H NMR
(CDCl3): δ -0.02 (s, 6H, Si-Me2), 1.23 (s, 18H, Flu-tBu2),
1.45 (s, 9H, Ar-tBu), 2.28 (s, 3H, Ar-Me), 4.40 (s, 1H, Cp0-H),
4.43 (dt, J=4.1, 1.8 Hz, 2H, OCH2CHdCH2), 5.33 (dq, J=10.7,
1.8 Hz, 1H, OCH2CHdCH2), 5.60 (dq, J = 17.3, 1.8 Hz, 1H,
OCH2CHdCH2), 6.09 (ddt, J = 17.3, 10.7, 4.0 Hz, 1H, OCH2-
CHdCH2), 6.97 (d, J = 2.1 Hz, 1H, Ar-H), 7.05 (s, 2H, Flu-H2),
7.26-7.32 (m, 3H), 7.70 (d, J = 8.1 Hz, 2H, Flu-H2). 13C NMR
(CDCl3): δ -3.16 (Si-Me2), 21.07 (Ar-Me), 31.51(Flu-CMe3),
31.56 (Ar-CMe3), 34.62 (Flu-CMe3), 35.31 (Ar-CMe3), 41.23,
76.19 (OCH2), 115.90, 118.74, 121.29, 122.15, 131.00, 131.53,
132.45, 133.79, 135.53, 138.05, 142.24, 145.50, 148.41, 161.57.
FD-MS: m/z 538 (Mþ). Anal. Calcd for C37H50OSi: C, 82.47; H,
9.35. Found: C, 82.30; H, 9.32.
(2-Allyloxy-3-tert-butyl-5-methylphenyl)(2,7-di-tert-butylfluo-
ren-9-yl)diethylsilane (1d). Mp: 100-105 °C (dec). 1H NMR
(CDCl3): δ 0.40-0.66 (m, 6H, Si-Et2), 0.72-1.04 (m, 4H,
Si-Et2), 1.24 (s, 18H, Flu-tBu2), 1.43 (s, 9H, Ar-tBu), 2.28
(s, 3H, Ar-Me), 4.39 (dt, J = 4.0, 1.8 Hz, 2H, OCH2CHdCH2),
4.47 (s, 1H, Cp0-H), 5.30 (dd, J = 10.9, 1.8 Hz, 1H, OCH2CHd
CH2), 5.57 (dd, J = 17.3, 1.8Hz, 1H, OCH2CHdCH2), 6.06 (ddt,
J = 17.3, 10.9, 3.8 Hz, 1H, OCH2CHdCH2), 6.96 (d, J = 2.1 Hz,
1H, Ar-H), 7.11 (s, 2H, Flu-H2), 7.27 (d, J = 8.1 Hz, 2H,
Flu-H2), 7.30 (d, J = 1.8 Hz, 1H, Ar-H), 7.67 (d, J = 8.1 Hz,
2H, Flu-H2). 13C NMR (CDCl3): δ 3.44 (Si-CH2CH3), 7.44
(Si-CH2CH3), 21.13 (Ar-Me), 31.46 (Ar-CMe3), 31.51 (Flu-
CMe3), 34.64 (Flu-CMe3), 35.26 (Ar-CMe3), 40.44, 76.01
(OCH2), 115.71, 118.79, 121.52, 122.15, 129.47, 130.78, 132.21,
133.81, 136.24, 138.10, 142.20, 145.78, 148.34, 161.75. FD-MS:
m/z 566 (Mþ). Anal. Calcd for C39H54OSi: C, 82.62; H, 9.60.
Found: C, 82.68; H, 9.58.
1
ZrCl2(NEt2)2 (6b). 1H NMR (THF-d8): δ 1.02 (t, J = 6.9 Hz,
12H, NCH2CH3), 3.48 (q, J = 6.9 Hz, 8H, NCH2CH3). 13C
NMR (THF-d8): δ 12.56 (NCH2CH3), 42.87 (NCH2CH3).
HfCl2(NMe2)2 (6c). 1H NMR (THF-d8): δ 3.05 (s, 12H,
NCH3). 13C NMR (THF-d8): δ 43.87 (NCH3).
Synthesis of (2-Allyloxy-3-tert-butyl-5-methylphenyl)(fluoren-
9-yl)dimethylsilane (1a). A typical procedure for the preparation
of 1a is given below. To a THF (112 mL) solution of fluorene (2a)
(5.00 g, 30.08 mmol) at 0 °C was addeda hexane solutionof nBuLi
(1.61 M, 19.6mL, 31.58 mmol). The reactionmixturewas allowed
to warm to 35 °C and then stirred for 2 h. To the mixture cooled
at -78 °C was added dropwise a toluene (14 mL) solution of
(2-allyloxy-3-tert-butyl-5-methylphenyl)chlorodimethylsilane (3a)
(9.82 g, 33.09 mmol). The resulting mixture was allowed to warm
to 35 °C and then stirred for 3 h. After the reaction mixture was
poured into a mixture of 10% aqueous NaHCO3 and 10%
aqueous Na2CO3, and the organic layer was extracted with
toluene and dried over Na2SO4. Removal of the solvent gave 1a
as a yellow oil. Obtained 1a was used in the next step without
further purification (as quantitative yield). Analytically pure
sample was prepared by the recrystallization from methanol;
mp: 84-85 °C (dec). 1H NMR(CDCl3): δ -0.02 (s, 6H, Si-Me2),
1.44 (s, 9H, Ar-tBu), 2.28 (s, 3H, Ar-Me), 4.38-4.42 (m, 3H),
5.25 (dq, J = 10.7, 1.8 Hz, 1H, OCH2CHdCH2), 5.52 (dq, J =
17.3, 1.8 Hz, 1H, OCH2CHdCH2), 6.03 (ddt, J = 17.3, 10.7, 4.1
Hz, 1H, OCH2CHdCH2), 6.96 (d, J = 1.6 Hz, 1H, Ar-H),
7.05-7.19 (m, 4H), 7.24-7.33 (m, 3H), 7.80 (d, J = 7.6 Hz, 2H,
Flu-H2). 13C NMR (CDCl3): δ -3.16 (Si-Me2), 21.10
(Ar-Me), 31.31 (Ar-CMe3), 35.26 (Ar-CMe3), 41.52, 76.33
(OCH2), 116.06, 119.65, 124.32, 125.16, 125.83, 130.66, 131.10,
132.52, 133.58, 135.36, 140.64, 142.15, 145.52, 161.55. FD-MS:
m/z 426 (Mþ). Anal. Calcd for C29H34OSi: C, 81.64; H, 8.03.
Found: C, 81.31; H, 8.38.
Synthesis of Dimethylsilylene(fluoren-9-yl)(3-tert-butyl-5-methyl-
2-phenoxy)titanium Dichloride (4a). Method B: To a toluene
(20 mL) solution of Et3N (5.34 g, 52.73 mmol) and 1a (5.00 g,
n
11.72 mmol) at -78 °C was added a hexane solution of BuLi
(1.61 M, 16.38 mL, 26.37 mmol). The mixture was allowed to
warm to room temperature and then stirred for 2 h. To the
mixture at-78°C was addeddropwise a toluene (15mL) solution
of TiCl2(NMe2)2 (6a) (2.91 g, 14.06 mmol). The resulting mixture
was warmed to room temperature and then heated to 90 °C
and stirred for 3 h. After cooling to room temperature, the
solvent was evaporated. Heptane was added, and insoluble
materials were removed by filtration. Removal of the solvent
gave [bis(dimethylamido)][dimethylsilylene(fluoren-9-yl)(3-tert-
butyl-5-methyl-2-phenoxy)]titanium (7) as a yellow oil (4.79 g).
Elemental analysis of 7 was failed due to the difficulty of the
purification, and the composition was determined by EI-HRMS.
1H NMR (CDCl3): δ 0.16 (s, 6H, Si-Me2), 1.39 (s, 9H, Ar-tBu),
2.32 (s, 3H, Ar-Me), 2.58 (s, 12H, N-Me2), 7.05-7.27 (m, 6H),
7.47 (d, J = 7.8 Hz, 2H, Flu-H2), 7.92 (d, J = 7.8 Hz, 2H, Flu-
H2). 13C NMR (CDCl3): δ -0.31 (Si-Me2), 21.21 (Ar-Me),
30.02 (Ar-CMe3), 34.93 (Ar-CMe3), 44.95 (N-Me2), 92.18,
119.34, 121.11, 122.46, 124.94, 129.05, 130.63, 133.97, 134.34,
135.29, 136.79, 143.61, 165.00. EI-HRMS: m/z Calcd 520.23894.
Found 520.23809.
(2-Allyloxy-3-tert-butyl-5-methylphenyl)(fluoren-9-yl)diethyl-
silane (1b). Mp: 110-113 °C (dec). 1H NMR (CDCl3): δ
0.43-0.64 (m, 6H, Si-Et2), 0.73-1.05 (m, 4H, Si-Et2), 1.43
(s, 9H, Ar-tBu), 2.27 (s, 3H, Ar-Me), 4.36-4.41 (m, 2H), 4.49
(s, 1H, Cp0-H), 5.26 (dq, J = 10.9, 1.8Hz, 1H, OCH2CHdCH2),
5.54 (dq, J = 17.1, 2.0 Hz, 1H, OCH2CHdCH2), 6.03 (ddt, J =
The above-obtained 7 (2.63 g) was dissolved in toluene
(58 mL) and cooled to 0 °C. To the mixture Me3SiCl (6.99 g,
64.35 mmol) was added dropwise. The resulting mixture was
warmed to 35 °C and then stirred for 3 h. After cooling to room
temperature, solvent was evaporated. Recrystallization from
pentane gave 4a as a brown solid (2.42 g, 75% yield, three steps

2304 Macromolecules, Vol. 43, No. 5, 2010
Senda et al.
from 2a); mp: 224-232 °C (dec). 1H NMR (CDCl3): δ 0.84
(s, 6H, Si-Me2), 1.18 (s, 9H, Ar-tBu), 2.44 (s, 3H, Ar-Me),
7.18 (s, 1H, Ar-H), 7.33 (s, 1H, Ar-H), 7.49 (dd, J = 8.4, 7.5
Hz, 2H, Flu-H2), 7.60 (dd, J = 8.4, 7.5 Hz, 2H, Flu-H2), 7.66
(d, J = 8.4 Hz, 2H, Flu-H2), 8.32 (d, J = 8.4 Hz, 2H, Flu-H2).
13C NMR (CDCl3): δ -0.02 (Si-Me2), 21.36 (Ar-Me), 29.76
(Ar-CMe3), 34.74 (Ar-CMe3), 108.51, 124.21, 128.06, 128.32,
129.26, 130.19, 131.21, 132.21, 132.35, 132.81, 134.32, 136.38,
168.32. Anal. Calcd for C26H28Cl2OSiTi: C, 62.04; H, 5.61.
Found: C, 61.75; H,5.64.
Diethylsilylene(fluoren-9-yl)(3-tert-butyl-5-methyl-2-phenoxy)-
titanium Dichloride (4b). Method B (0.94 g, 29% yield, three steps
from2a). Brownsolid; mp: 190-198 °C (dec). 1H NMR(CDCl3):
δ 1.07 (t, J = 7.7 Hz, 6H, Si-Et2), 1.18 (s, 9H, Ar-tBu), 1.28-
1.50 (m, 4H, Si-Et2), 2.44 (s, 3H, Ar-Me), 7.18 (d, J = 1.8 Hz,
1H, Ar-H), 7.28 (d, J = 1.8 Hz, 1H, Ar-H), 7.43-7.52 (m, 2H),
7.56-7.67 (m, 4H), 8.28 (d, J = 8.4 Hz, 2H, Flu-H2). 13C NMR
(CDCl3): δ 5.35 (Si-CH2CH3), 7.60 (Si-CH2CH3), 21.42
(Ar-Me), 29.80 (Ar-CMe3), 34.72 (Ar-CMe3), 107.47,
124.22, 128.25, 128.28, 129.25, 129.63, 130.29, 131.22, 132.57,
133.56, 133.87, 136.47, 168.91. Anal. Calcd for C28H32Cl2OSiTi:
C, 63.28; H, 6.07. Found: C, 63.40; H, 6.13.
7.16 (s, 1H, Ar-H), 7.29 (s, 1H, Ar-H), 7.56 (s, 2H, Flu-H2),
7.64 (d, J = 8.9 Hz, 2H, Flu-H2), 8.18 (d, J = 8.9 Hz, 2H,
Flu-H2). 13C NMR (CDCl3): δ 5.55 (Si-CH2CH3), 7.76
(Si-CH2CH3), 21.39 (Ar-Me), 30.04 (Ar-CMe3), 30.81
(Flu-CMe3), 34.71 (Ar-CMe3), 35.33 (Flu-Me3), 106.80,
123.00, 123.67, 127.54, 128.92, 129.07, 129.45, 133.09, 133.50,
133.56, 136.21, 153.68, 168.60. Anal. Calcd for C36H48Cl2OSi-
Ti-0.5(C7H8): C, 68.79; H, 7.60. Found: C, 68.54; H, 7.97.
Dimethylsilylene(2,7-di-tert-butylfluoren-9-yl)(3-tert-butyl-5-
methyl-2-phenoxy)zirconium Dichloride (8). The zirconium com-
plex was prepared analogously using ZrCl4 instead of TiCl4
(method A) or ZrCl2(NEt2)2 (6b) instead of TiCl2(NMe2)2 (6a)
(method B). Method A: (0.58 g, 22% yield, two steps from 2b).
Method B: (1.92 g, 78% yield, three steps from 2b). Elemental
analysis indicated that 8 contained 0.5 equiv of LiCl, and the LiCl
free composition was determined by EI-HRMS. Yellow solid;
1
mp: 244-253 °C (dec). H NMR (toluene-d8): δ 0.80 (s, 6H,
Si-Me2), 1.19 (s, 18H, Flu-tBu2), 1.33 (s, 9H, Ar-tBu), 2.30 (s,
3H, Ar-Me), 7.21 (d, J=1.9 Hz, 1H, Ar-H), 7.36(dd, J=8.9Hz,
1.6 Hz, 2H, Flu-H2), 7.38 (d, J = 1.9 Hz, 1H, Ar-H), 7.76 (s,
2H, Flu-H2), 7.89 (d, J = 8.9, 2H, Flu-H2). 13C NMR (toluene-
d8): δ 0.06 (Si-Me2), 21.25 (Ar-Me), 30.28 (Ar-CMe3), 30.85
(Flu-CMe3), 34.90 (Ar-CMe3), 35.36 (Flu-CMe3), 89.16,
120.84, 123.73, 124.12, 125.39, 128.99, 130.02, 132.42, 132.56,
134.93, 137.45, 153.45, 162.91. Anal. Calcd for C34H44Cl2OSiZr-
0.5(LiCl): C, 60.04; H, 6.52. Found: C, 60.20; H, 6.82. EI-HRMS:
m/z Calcd 656.15855. Found 656.15771.
Synthesis of Dimethylsilylene(2,7-di-tert-butylfluoren-9-yl)(3-
tert-butyl-5-methyl-2-phenoxy)titanium Dichloride (4c). Method
A: To a toluene (48 mL) solution of Et3N (1.84 g, 18.23 mmol)
and 1c (2.18 g, 4.05 mmol) at -78 °C, was added a hexane
n
solution of BuLi (1.58 M, 5.77 mL, 9.11 mmol). The mixture
was allowed to warm to room temperature and then stirred for
2 h. To the mixture at -78 °C was added dropwise a toluene
(6 mL) solution of TiCl4 (1.15 g, 6.08 mmol). The resulting
mixture was warmed to room temperature and then heated to
90 °C and stirred for 3 h. After cooling to room temperature, the
solvent was evaporated. Hexane was added, and insoluble
materials were removed by filtration. Removal of the solvent
and addition of pentane gave 5 as colorless solids (0.371 g, 18%
yield, two steps from 2b). 4c was obtained as brown solids by
recrystallization from pentane soluble part after removal of 5
(0.300 g, 12% yield, two steps from 2b).
Dimethylsilylene(2,7-di-tert-butylfluoren-9-yl)(3-tert-butyl-5-
methyl-2-phenoxy)hafnium Dichloride (9). The hafnium com-
plex was prepared analogously using HfCl4 instead of TiCl4
(method A) or HfCl2(NMe2)2 (6c) instead of TiCl2(NMe2)2 (6a)
(method B). Method A: (0.16 g, 5% yield, two steps from 2b).
Method B: (1.60 g, 58% yield, three steps from 2b). Pale yellow
solid; mp: 220-229 °C (dec). 1H NMR (CD2Cl2): δ 0.83 (s, 6H,
Si-Me2), 1.18 (s, 9H, Ar-tBu), 1.25 (s, 18H, Flu-tBu2), 2.40
(s, 3H, Ar-Me), 7.20 (d, J = 1.6 Hz, 1H, Ar-H), 7.35 (d, J =
1.6 Hz, 1H, Ar-H), 7.59 (dd, J = 8.9 Hz, 1.6 Hz, 2H, Flu-H2),
7.65 (br s, 2H, Flu-H2), 8.19 (d, J = 8.9 Hz, 2H, Flu-H2). 13
C
Dimethylsilylene(2,7-di-tert-butylfluoren-9-yl)(3-tert-butyl-5-
methyl-2-phenoxy)titanium Dichloride (4c). Mp: 217-218 °C
NMR (CD2Cl2): δ 0.22 (Si-Me2), 21.13 (Ar-Me), 30.12 (Ar-
CMe3), 30.95 (Flu-CMe3), 34.72 (Ar-CMe3), 35.55 (Flu-
CMe3), 85.95, 120.64, 121.93, 123.97, 125.32, 129.06, 129.97,
132.41, 132.80, 134.53, 137.28, 153.56, 161.77. Anal. Calcd for
C34H44Cl2HfOSi: C, 54.73; H, 5.94. Found: C, 54.34; H, 6.09.
Crystallographic Analyses of 4d and 5. All crystals were
handled similarly. The crystals were mounted on the CryoLoop
(Hampton Research Corp.) with a layer of light mineral oil and
placed in a nitrogen stream at 113(2) K. All measurements were
made on a Rigaku AFC7R/Mercury CCD detector with gra-
1
(dec). H NMR (CDCl3): δ 0.84 (s, 6H, Si-Me2), 1.18 (s, 9H,
Ar-tBu), 1.26 (s, 18H, Flu-tBu2), 2.43 (s, 3H, Ar-Me), 7.16 (d,
J = 2.0 Hz, 1H, Ar-H), 7.34 (d, J = 2.0 Hz, 1H, Ar-H), 7.57
(s, 2H, Flu-H2), 7.65 (d, J = 8.9 Hz, 1H, Flu-H), 7.65 (d, J =
8.9 Hz, 1H, Flu-H), 8.19 (d, J = 8.9 Hz, 2H, Flu-H2). 13C
NMR (CDCl3): δ -0.12 (Si-Me2), 21.35 (Ar-Me), 29.98
(Ar-CMe3), 30.81 (Flu-CMe3), 34.75 (Ar-CMe3), 35.33
(Flu-CMe3), 107.92, 122.73, 123.70, 127.59, 128.86, 129.12,
132.13, 132.50, 133.19, 133.91, 136.15, 153.64, 167.99. Anal.
Calcd for C34H44Cl2OSiTi: C, 66.34; H, 7.20. Found: C, 65.86;
H, 7.19.
˚
phite-monochromated Mo KR (0.710 75 A) radiation. Crystal
data and structure refinement parameters are summarized in
Table S1. The structures were solved by direct methods (SIR
92)24 and refined on F2 using a full-matrix least-squares methods
(SHELXL-97).25 Non-hydrogen atoms were anisotropically
refined for 5. In the case of 4d, non-hydrogen atoms were
anisotropically refined except for a disordered solvent molecule,
which was refined isotropically. H atoms were included in the
1
Compound 5. Mp: 254-258 °C (dec). H NMR (CDCl3): δ
0.03 (s, 6H, Si-Me2), 1.27 (s, 18H, Flu-tBu2), 1.33 (s, 9H,
Ar-tBu), 2.39 (s, 3H, Ar-Me), 7.18-7.22 (m, 2H, Ar-H2), 7.29
(s, 2H, Flu-H2), 7.32 (d, J = 7.9 Hz, 1H, Flu-H), 7.33 (d, J =
7.9 Hz, 1H, Flu-H), 7.61 (d, J = 7.9 Hz, 2H, Flu-H2). 13C
NMR (CDCl3): δ -2.02 (Si-Me2), 20.87 (Ar-Me), 29.41 (Ar-
CMe3), 31.43 (Flu-CMe3), 34.66 (Ar-CMe3), 34.74 (Flu-
CMe3), 86.35, 119.36, 121.17, 121.50, 123.89, 129.39, 130.11,
130.70, 135.02, 136.04, 147.49, 149.53, 164.55. FD-MS: m/z 496
(Mþ). Anal. Calcd for C34H44OSi: C, 82.20; H, 8.93. Found: C,
81.84; H, 9.00.
refinement on calculated positions riding on their carrier atoms.
The function minimized was [ w(Fo2 - Fc ) ] (w = 1/[σ2(Fo2) þ
P
2 2
2
(aP)2 þ bP]), where P = (Max(Fo2,0) þ 2Fc )/3 with σ2(Fo2) from
P
counting statistics. The functions R1 and wR2 were ( | Fo| -
P
P
P
|Fc |)/( |Fo|) and [{ w(Fo -Fc2)2}/{ (wFo )}]1/2, respectively.
The ORTEP-3 program (for Windows, version 2.02)26 was used
to draw the molecule.
2
4
Diethylsilylene(2,7-di-tert-butylfluoren-9-yl)(3-tert-butyl-5-meth-
yl-2-phenoxy)titanium Dichloride (4d). Elemental analysis indi-
cated that 4d contained 0.5 equiv of toluene, and the existence
of 0.5 equiv of toluene in crystal was also confirmed by X-ray
analysis. Method A (6.73 g, 24% yield, two steps from 2b).
Brown solid; mp: 119-127 °C (dec). 1H NMR (CDCl3): δ 1.09
(t, J = 7.7 Hz, 6H, Si-Et2), 1.18 (s, 9H, Ar-tBu), 1.25 (s, 18H,
Flu-tBu2), 1.26-1.48 (m, 4H, Si-Et2), 2.43 (s, 3H, Ar-Me),
Primary Screening Procedure. A Symyx PPR system was used
for primary screening experiments. A typical procedure for the
copolymerization of ethylene and 1-hexene at 70 °C is given as
follows: Other polymerizations at 130 °C were carried out
analogously. A prewashed glass vial insert and disposable
stirring paddle were fitted to each reaction vessel of the reactor.
The reactor was then closed, and TIBA (40 μmol, 160 μL, 0.25 M

Article
Macromolecules, Vol. 43, No. 5, 2010 2305
toluene solution), 1-hexene (50 μL), and toluene were injected
into each reaction vessel through a valve. The total volume of
the reaction mixture was adjusted with toluene to 5 mL. The
temperature was then set to 70 °C, the stirring speed was set to
800 rpm, and the mixture was pressurized with ethylene to
0.6 MPa. Polymerization was started by addition of a toluene
solution of complex (0.1 μmol, 1 mM toluene solution) followed
by a toluene solution of AB (0.3 μmol, 1 mM toluene solution).
Ethylene pressure in the cell and the temperature setting were
maintained by computer control until the end of the polymer-
ization experiment. The polymerization reactions were allowed
to continue for 20 min unless consumption of ethylene reached
preset levels. After polymerization reaction, the reaction mix-
ture was allowed to cool 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 compo-
nents were removed using a centrifuge vacuum evaporator to
give polymer product.
Copolymerization of Ethylene and 1-Hexene at High Tem-
perature. An autoclave with an inner volume of 400 mL was
dried under vacuum and purged with argon. After charging with
toluene (185 mL) and 1-hexene (15 mL), the autoclave was
heated to 180 °C. Ethylene was introduced to the vessel, and the
pressure was adjusted at 2.5 MPa. After the system was stabi-
lized TIBA (0.3 mmol) was added to the mixture. Subsequently,
titanium complex (0.5 μmol) and AB (3.0 μmol) were added.
Polymerization was performed at 180 °C for 2 min, and then the
reaction was quenched with ethalnol/methanol (9:1) (5 mL). The
reaction mixture was poured into acidic ethanol/methanol (9:1)
(500 mL with 1 mL of 5% HCl). The polymer was collected by
filtration, washed with methanol, and dried under high vacuum
at 80 °C for 2 h to constant weight.
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(10) We recently reported that PHENICS-Ti bearing the dithiophene-
fused cyclopentadienyl ligands significantly increased the molecu-
lar weight of the copolymer of ethylene and 1-hexene even at
180 °C. See: Senda, T.; Hanaoka, H.; Okado, Y.; Oda, Y.; Tsurugi,
H.; Mashima, K. Organometallics 2009, 28, 6915–6926.
(11) Fluorenyl ligand systems are preferable to dithiophene-fused cy-
clopentadienyl ligands systems because of availability of various
kinds of fluorene compounds applicable to fine-tuning of ligand
architecture.
(12) The preliminary example, in which dilithium salt of 1a with ZrCl4
was reacted under similar conditions, resulted in replacement of all
four chlorides at the metal center with formation of spiro-metallo-
cene [Me2Si(fluoren-9-yl)(3-tBu-5-Me-2-C6H2O)]2Zr as an EI-MS
detectable product. EI-MS: m/z 858 (Mþ). For similar formation of
spiro-metallocenes, see: (a) Herrmann, W. A.; Morawietz, M. J. A.;
Priermeier, T. Angew. Chem., Int. Ed. Engl. 1994, 33, 1946–1949.
(b) Christoffers, J.; Bergman, R. G. Angew. Chem., Int. Ed. Engl.
1995, 34, 2266–2267. (c) Chen, Y.-X.; Fu, P.-F.; Stern, C. L.;
Marks, T. J. Organometallics 1997, 16, 5958–5963. (d) Duda, L.;
Acknowledgment. The authors thank Dr. Hirofumi Hamaki
(Sumitomo Chemical) for his experimental assistance and Mr.
Takahiro Hino (Sumitomo Chemical) and Mr. Takuto Nakayama
(Sumitomo Chemical) for primary screening polymerization.
Supporting Information Available: Figures showing NMR
spectra of 7 and 8 and table of crystal data for 4d and 5. This
material is available free of charge via the Internet at http://
pubs.acs.org.
€
Erker, G.; Frohlich, R.; Zippel, F. Eur. J. Inorg. Chem. 1998, 1153–
1162. (e) Thorn, M. G.; Fanwick, P. E.; Chesnut, R. W.; Rothwell,
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