Synthesis, structures, and catalytic properties for ethylene polymerization of bridged [η5,η1-C5H4CHPhArO]TiCl2 complexes

Article abstract of DOI:10.1016/j.jorganchem.2008.01.010

A number of bridged half-sandwich titanium complexes [η⁵:η¹-2-C₅H₄CHPh-4-R¹-6-R²C₆H₂O]TiCl₂ [R¹ = H (5), Me (6), ^tBu (7, 8); R²

Full text of DOI:10.1016/j.jorganchem.2008.01.010

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 693 (2008) 1195–1202
www.elsevier.com/locate/jorganchem
Synthesis, structures, and catalytic properties for ethylene
polymerization of bridged [g5,g1-C5H4CHPhArO]TiCl2 complexes
Tingting Xiao a, Jianhui Wang b, Yuetao Zhang a, Wei Gao a, Ying Mu a,*
a State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street,
Changchun 130012, People’s Republic of China
b Department of Chemistry, College of Science, Tianjin University, Tianjin 300072, People’s Republic of China
Received 6 December 2007; received in revised form 7 January 2008; accepted 8 January 2008
Available online 12 January 2008
Abstract
t
A number of bridged half-sandwich titanium complexes [g5:g1-2-C5H4CHPh-4-R1-6-R2C6H2O]TiCl2 [R1 = H (5), Me (6), Bu (7,8);
R2 = H (6,7), tBu (5,8)] were synthesized from the reaction of their corresponding trimethylsilyl substituted ligand precursors
t
t
2-Me3SiC5H4CHPh-4-R1-6-R2C6H2OSiMe3 [R1 = H (1), Me (2), Bu (3,4); R2 = H (2,3), Bu (1,4)] with TiCl4 in hexane. All new
complexes were characterized by 1H and 13C NMR spectroscopy. Molecular structures of complexes 5 and 8 were determined by single
crystal X-ray diffraction analysis. Upon activation with AliBu3/Ph3CB (C6F5)4, complexes 5–8 exhibit reasonable catalytic activity for
ethylene polymerization and copolymerization with 1-hexene, producing polyethylene and poly(ethylene-co-1-hexene) with moderate
molecular weights.
Ó 2008 Elsevier B.V. All rights reserved.
Keywords: Ethylene polymerization; Cyclopentadienyl complexes; Metallocene; Titanium complexes
1. Introduction
CGC catalysts of type I, the catalysts with a pendent oxy-
gen donor on the cyclopentadienyl ring received relatively
less attention and have not been studied systematically
[1c]. We and other groups have developed a number of
CGC catalysts of the type [g5:g1-C5R4–ArO]TiCl2 (II)
and found that these catalysts produce ethylene/a-olefin
copolymers with relatively low molecular weights due
probably to their ligands are not bulky enough [4c]. Similar
catalysts with a formula of [g5:g1-C5H4–CR2–ArO]TiCl2
(III) were also synthesized, but no study on ethylene/a-ole-
fin copolymerization has been reported [7]. Considering
that the ligands of the complexes III have a longer linkage
and thus are bulkier than those of the catalysts II, com-
plexes III might be more suitable catalysts for producing
ethylene/a-olefin copolymers with higher molecular
weights. We have synthesized a number of new half-
sandwich titanium complexes [g5:g1-2-C5H4CHPh-4-R1-
Since 1990s, the so-called constrained geometry metallo-
cene catalysts (CGC) with the general formula of [g5:g1-
C5Me4(SiMe2)NtBu]TiCl2 (I) (see Chart 1) have been
widely studied in academic [1] and industrial [2] institutions
because of their high performance in catalyzing the copoly-
merization of different olefins. So far, various modifications
on the chelating ligand have been conducted in order to
improve the catalytic performance of the CGC catalysts
and study the steric and electronic effects of the ligands
on their catalytic properties. For example, a variety of
CGC catalysts with ligands bearing different substituted
cyclopentadienyl, indenyl and fluorenyl groups [3,4], differ-
ent coordinating heteroatoms [5], and different linkages [6]
have been synthesized and studied. In comparison with the
t
6-R2C6H2O]TiCl2 [R1 = H (5), Me (6), Bu (7,8); R2 = H
*
Corresponding author. Tel.: +86 431 85168376; fax: +86 431
t
(6,7), Bu (5,8)] from the reaction of their corresponding
85193421.
trimethylsilyl substituted ligand precursors 2-Me3SiC5-
E-mail address: ymu@mail.jlu.edu.cn (Y. Mu).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.01.010

1196
T. Xiao et al. / Journal of Organometallic Chemistry 693 (2008) 1195–1202
R
R
R
R
R
R1
R
Cl
Cl
Si
Cl
Cl
Ti
Ti
N
Cl
Cl
O
O
tBu
R2
II
Chart 1.
I
III
t
H4CHPh-4-R1-6-R2C6H2OSiMe3 [R1 = H (1), Me (2), Bu
tron-donating ability of R1 and R2 groups leads to higher
yields, which may be ascribed to the difference in the nucle-
ophilicity of the dilithium salt of corresponding phenol [4c].
(3,4); R2 = H (2,3), Bu (1,4)] with TiCl4. In this paper,
t
we report the synthesis and characterization of the new
ligand precursors 1–4 and their titanium complexes 5–8,
as well as the catalytic performance of complexes 5–8 for
ethylene polymerization and copolymerization with 1-
hexene.
1
Compounds 1–4 were all characterized by H NMR spec-
troscopy. Ligand precursors 2-C5H5CHPh-4-R1-6-R2C6-
H2OH [R1 = H, R2 = tBu; R1 = Me, R2 = H; R1 = tBu;
t
R2 = H, Bu] could also be synthesized from the reaction
of 6-plenylfulvene with the dilithium salt of corresponding
phenol by quenching the reaction before the addition of
Me3SiCl [4b]. Dilithium salts of these ligands could be
obtained too before the reaction with Me3SiCl. However,
it was found that the trimethylsilyl substituted ligand
precursors 1–4 are better starting materials for the synthe-
sis of the titanium (IV) dichloride complexes 5–8, and the
ligand precursors 2-C5H5CHPh-4-R1-6-R2C6H2OH and
their dilithium salts are not necessary to be isolated.
The titanium complexes 5–8 were synthesized in moder-
ate yields by the TMSCl elimination reaction [8] of the tri-
methylsilyl substituted ligand precursors 1–4 with TiCl4 in
hexane. The yields of the complexes 5–8 were also found to
2. Results and discussion
2.1. Synthesis of ligand precursors and titanium complexes
The trimethylsilyl substituted ligand precursors 1–4 were
synthesized (Scheme 1) by treatment of 6-plenylfulvene
with the dilithium salt of corresponding phenol prepared
in situ from the reaction of corresponding o-bromophenol
with 2 equiv. n-BuLi in diethyl ether, followed by reaction
with Me3SiCl in diethyl ether [3c]. The yields of compounds
1–4 were found to be sensitive to the nature of the R1 and
R2 groups on the phenol ring. It seems that stronger elec-
OH
OLi
H
Br
R2
R2
1.
2 eq. nBuLi
in Et2O
Li
Ph
2. 2 eq. TMSCl
in Et2O
R1
R1
OTMS
Ph
H
H
Cl
Cl
Ph
R2
Ti
TMS
TiCl4
in Hexane
O
R2
R1
R1
R1 = H (1), Me (2), tBu (3, 4)
R2 = H (2, 3), tBu (1, 4)
R1 = H (5), Me (6), tBu (7, 8)
R2 = H (6, 7), tBu (5, 8)
Scheme 1. Synthesis of compounds 1–4 and complexes 5–8.

T. Xiao et al. / Journal of Organometallic Chemistry 693 (2008) 1195–1202
1197
be sensitive to the R1 and R2 groups on the phenol ring of
their ligands, and similar trend to that mentioned above for
the synthesis of compounds 1–4 was observed. That is,
stronger electron-donating ability of R1 and R2 groups
results in higher yields due probably to stronger coordina-
tion ability of corresponding ligands and ligand precursors.
The synthesis of these titanium complexes was also tried by
the reaction of the dilithium salt of corresponding ligand
with TiCl4 [4c], from which complexes 5–8 were obtained
in lower yields. All new Ti complexes 5–8 were character-
1
ized by means of H and 13C NMR spectroscopy and ele-
mental analysis, and the structures of complexes 5 and 8
were determined by single crystal X-ray crystallography.
2.2. Crystal structures of 5 and 8
The molecular structures of complexes 5 and 8 were
determined by single crystal X-ray diffraction analysis.
The ORTEP drawings of the molecular structures of 5
and 8 are shown in Figs. 1 and 2, respectively. The selected
bond lengths and angles are summarized in Table 1. Both
complexes 5 and 8 adopt a pseudo-tetrahedral geometry
with the sterically open feature in front of the central metal
atom required for olefin copolymerization catalysts. The
Cp (cent)–Ti–O angles for 5 and 8 are 111.6° and 109.5°,
respectively, which are slightly bigger than the Cp(cent)–
Ti–N angle in I (107.6°) [2a] and the Cp(cent)–Ti–O angle
in II (106.8–107.3°) [4b]. The Cp(cent)–Ti distances of 5
Fig. 2. Structure of complex 8 (thermal ellipsoids are drawn at the 30%
probability level).
Table 1
Selected bond lengths and angles
Complex 5
Ti(1)–O(1)
Ti(1)–C(2)
Ti(1)–C(4)
Ti(1)–Cl(1)
O(1)–C(6)
C(1)–C(18)
1.792(2)
2.323(4)
2.334(4)
2.252(2)
1.371(4)
1.522(5)
Ti(1)–C(1)
Ti(1)–C(3)
Ti(1)–C(5)
Ti(1)–Cl(2)
Cp(cent)–Ti(1)
C(11)–C(18)
2.322(4)
2.341(4)
2.314(5)
2.2543(17)
1.997
1.536(5)
˚
˚
(1.997 A) and 8 (1.995 A) are much shorter than that in I
O(1)–Ti(1)–Cl(1)
Cl(1)–Ti(1)–Cl(2)
Ti(1)–Cp(cent)–C(1)
C(1)–C(18)–C(11)
C(11)–C(6)–O(1)
103.97(11)
106.12(8)
89.3
169.5
118.7(3)
O(1)–Ti(1)–Cl(2)
Cp(cent)–Ti(1)–O(1)
Cp(cent)–C(1)–C(18)
C(18)–C(11)–C(6)
C(6)–O(1)–Ti(1)
102.26(9)
111.6
179.2
123.5(3)
148.2(2)
˚
˚
(2.340 A) [2a] and II (2.335–2.348 A) [4b]. The Ti–O bond
˚
˚
lengths of 1.792(2) A in 5 and 1.794(3) A in 8 are slightly
Complex 8
Ti(1)–O(1)
Ti(1)–C(2)
Ti(1)–C(4)
Ti(1)–Cl(1)
O(1)–C(6)
C(1)–C(18)
1.794(3)
2.306(4)
2.346(5)
2.2523(14)
1.384(4)
1.501(5)
Ti(1)–C(1)
Ti(1)–C(3)
Ti(1)–C(5)
Ti(1)–Cl(2)
Cp(cent)–Ti(1)
C(11)–C(18)
2.310(4)
2.345(5)
2.318(5)
2.2578(13)
1.995
1.531(5)
O(1)–Ti(1)–Cl(1)
Cl(1)–Ti(1)–Cl(2)
Ti(1)–Cp(cent)–C(1)
C(1)–C(18)–C(11)
C(11)–C(6)–O(1)
104.66(10)
103.79(6)
88.5
169.5
119.0(4)
O(1)–Ti(1)–Cl(2)
Cp(cent)–Ti(1)–O(1)
Cp(cent)–C(1)–C(18)
C(18)–C(11)–C(6)
C(6)–O(1)–Ti(1)
104.56(9)
109.5
177.7
122.6(4)
147.1(3)
˚
shorter than the Ti–O bonds in II [1.832(3)–1.837(2) A]
[4b], while the Ti–O–C angles of 148.2(2)° for 5 and
147.1(3)° for 8 are much larger than the Ti–O–C angle in
II [128.34(18)–128.9(3)°] [4b]. These results indicate the
Ti–O double-bond character in complexes 5–8 is stronger
than that in complexes II [9,10]. In comparison to com-
plexes II, the larger Cp(cent)–Ti–O and Ti–O–C angles in
5 and 8 make these complexes possessing less space in front
of the central titanium atom and thus probably being better
catalysts for producing polyolefins with higher molecular
weights.
Fig. 1. Structure of complex 5 (thermal ellipsoids are drawn at the 30%
probability level).

1198
T. Xiao et al. / Journal of Organometallic Chemistry 693 (2008) 1195–1202
2.3. Ethylene polymerization studies
weight of the polyethylenes formed by complexes 5–8 is
obviously improved. The order of the catalytic activity
for ethylene polymerization under similar conditions (see
runs 1, 4, 7, and 12 in Table 2) is 8 > 5 > 7 > 6, which could
be attributed to the nature of the substituents on the phen-
oxy group in these complexes. It seems that the catalytic
activity of these complexes is directly related to the elec-
tron-donating ability of both R1 and R2 groups [11]. By
examining the structure and catalytic activity of 5 and 7,
it can also be seen that the steric effect of the R2 group at
the ortho position of the phenolate plays a role too in
determining the order of their catalytic activity. For all
complexes, the catalytic activity increases with the increase
in Al/Ti ratio and reaches the highest values with the Al/Ti
ratio of 150. Further increase in Al/Ti ratio results in a
decrease in the catalytic activity. Similar results have been
obtained with other metallocene catalyst systems [12]. The
catalytic activity of these complexes is low at room temper-
ature and increases with the polymerization temperature.
Reasonable catalytic activity was obtained at temperatures
higher than 70 °C, which reflects the nature of tight interac-
tion between the catalyst cation and the cocatalyst anion in
the constrained geometry catalyst systems [13]. The cata-
lytic activity reaches the highest at 90 °C and begins to
decrease with the further increase in temperature, which
is ascribed to that the concentrations of ethylene and the
active species would decrease at higher temperature [14].
The molecular weight of the obtained polyethylene is
dependent on the structure of the catalyst and polymeriza-
tion conditions as seen in Table 2. Catalysts 5 and 8 pro-
duce polyethylenes with relatively high molecular weights
Complexes 5–8 were studied as ethylene polymerization
catalysts and the results are summarized in Table 2. Upon
activation with Al(iBu)3 and Ph3CB(C6F5)4, complexes 5–8
all show good catalytic activity for ethylene polymerization
and produce polyethylenes with moderate molecular
weights and melting temperatures. In comparison to the
polymers obtained with catalysts II [4], the molecular
Table 2
Summary of ethylene polymerization catalyzed by 5–8/AliBu3/
Ph3CB(C6F5)a4
No. Catalyst Al:Ti
T
Yield
(g)
Activityb  Mgc  Tm
(°C)
106
10À3
(°C)d
1
2
3
4
5
6
7
8
5
5
5
6
6
6
7
7
7
7
7
8
8
8
8
8
120
150
180
120
150
180
120
150
180
150
150
120
150
180
150
150
90
90
90
90
90
90
90
90
90
70
110
90
90
90
70
110
2.82
3.06
2.14
1.68
1.93
1.27
2.2
2.52
2.04
1.96
1.42
3.39
3.54
3.19
3.04
2.89
2.82
3.06
2.14
1.68
1.93
1.27
2.2
2.52
2.04
1.96
1.42
3.39
3.54
3.19
3.04
2.89
137
126
111
79
66
55
106
93
79
143
61
172
156
141
216
102
138.9
138.8
138.6
137.6
137.3
136.6
138.5
138.1
137.9
139.2
137.2
139.3
139.6
139.1
140.6
138.5
9
10
11
12
13
14
15
16
a
Polymerization conditions: solvent 60 ml of toluene, catalyst
2 Â 10À6 mol, B/Ti ratio 1.5, time 30 min, ethylene pressure 6 bar.
t
g PE(mol Ti)À1 hÀ1
.
b
under similar conditions, due probably to that the Bu
c
group at the ortho position of the phenolate could slow
down the chain transfer or chain termination reaction in
some extent.
Measured in decahydronaphthalene at 135 °C.
Determined by DSC at a heating rate of 10 °C minÀ1 and the data
d
from second scan are used.
Table 3
Summary of ethylene copolymerization with 1-hexene catalyzed by 5–8/AliBu3/Ph3CB(C6F5)a4
No.
Catalyst
1-Hexene (mol/l)
Yield (g)
Activityb  106
1-Hexene contentc (%)
Mgd  10À3
Tm (°C)e
1
2
3
4
5
6
7
8
5
5
5
6
6
6
7
7
7
8
8
8
8
8
0.2
0.5
0.8
0.2
0.5
0.8
0.2
0.5
0.8
0.2
0.35
0.5
0.65
0.8
0.76
0.71
0.61
0.56
0.50
0.40
0.70
0.63
0.55
0.80
0.77
0.76
0.71
0.65
4.57
4.23
3.67
3.34
3.00
2.40
4.19
3.80
3.29
4.79
4.63
4.53
4.24
3.89
7.88
16.03
24.32
8.53
17.57
25.11
7.96
16.39
24.03
7.10
11.93
15.69
19.49
23.68
91
57
8.9
83
36
7.9
89
43
8.8
97
85
66
42
9.8
122.3
111.5
107.3
120.6
110.0
107.1
121.9
110.7
107.3
122.8
117.3
112.1
110.6
107.6
9
10
11
12
13
14
a
Polymerization conditions: solvent 60 ml of toluene, temperature 90 °C, catalyst 2 Â 10À6 mol, B/Ti ratio 1.5, Al/Ti ratio 150, time 10 min, ethylene
pressure 6 bar.
g polymer (mol Ti)À1 hÀ1
Calculated by 13C NMR spectra.
.
b
c
d
e
Measured in xylene at 105 °C.
Determined by DSC at a heating rate of 10 °C minÀ1 and the data from second scan are used.

T. Xiao et al. / Journal of Organometallic Chemistry 693 (2008) 1195–1202
1199
2.4. Copolymerization of ethylene with 1-hexene
1-hexene, respectively) were calculated from Finemane–
Ross plots [17] as shown in Fig. 3. The value of reactivity
ratio products rErH is close to 1, which demonstrates that
the ethylene/1-hexene copolymerization proceeds in a ran-
dom manner. Table 4 summarizes selected triad sequence
distributions (monomer sequences) and dyads in the resul-
tant copolymers estimated by 13C NMR spectra. The
results suggest that the monomer sequence distributions
in the copolymers produced by 5–8 are basically indepen-
dent on the substituents R1 and R2 in their ligands [16].
Complexes 5–8 were also tested for copolymerization of
ethylene with 1-hexene, and the results are summarized in
Table 3. It can be seen that the copolymerization catalytic
activity of these catalysts changes in the same order as that
observed in the ethylene homopolymerization under simi-
lar conditions. 13C NMR analysis of the obtained copoly-
mers indicates reasonable incorporation of 1-hexene into
the polymer chains for all catalyst systems. As expected,
the 1-hexene content of the copolymers produced by 5–8
is comparable to that of copolymers formed by catalysts
II, while the molecular weight of the copolymers resulted
from 5–8 is obviously improved in comparison to that of
the latter copolymers under similar conditions [4c]. How-
ever, both the 1-hexene content and the molecular weight
of the copolymers produced by 5–8 are lower than those
of copolymers from related non-bridged C5R5TiCl2(OAr)
catalyst systems [15]. As can be seen from Table 3, the
molecular weight of the obtained copolymers is sensitive
to the microstructure of the catalyst and polymerization
conditions. The melting temperature and molecular weight
of the copolymers are also dependent on the 1-hexene con-
tent [16] and decrease as the 1-hexene content increases (see
runs 10–14 in Table 3). The ethylene and 1-hexene reactiv-
ity ratios (rE and rH are the reactivity ratios of ethylene and
3. Experimental
3.1. General details
All manipulations of air-sensitive materials were per-
formed with rigorous exclusion of oxygen and moisture
using standard Schlenk techniques [18]. Ether and toluene
were refluxed over sodium benzophenone ketyl under nitro-
gen and distilled before use. CH2Cl2 and n-hexane were
refluxed over CaH2 and distilled under nitrogen before
use [19]. Polymerization grade ethylene was further purified
˚
by passage through columns of 5 A molecular sieves and
MnO. Al(iBu)3, nBuLi, and TiCl4 were purchased from
Aldrich. 2-bromothenol [9], 6-plenylfulvene [20] and
Ph3CB(C6H5)4 [21] were prepared according to literature
procedures. NMR spectra were recorded on a Varian Mer-
cury-300 or a Varian Utility-400 NMR spectrometer.
1.8
r =0.147
rEHrE=1.043
3.2. Preparation of 2-Me3SiC5H4CHPh-6-tBuC6H3OSiMe3
(1)
rH=7.097
1.6
1.4
A
solution of 2-bromo-2-tert-butylphenol (1.63 g,
1.2
1.0
0.8
0.6
0.4
0.2
7.13 mmol) in Et2O (20 ml) was added dropwise to a solu-
tion of BuLi (14.3 mmol) in Et2O (10 ml) at À15 °C. The
n
mixture was slowly warmed to room temperature and stir-
red for 6 h. To this solution was slowly added 6-phenylful-
vene (1.10 g, 7.13 mmol) in Et2O (10 ml) at À15 °C over
1 h. The resulting solution was then allowed to warm to
room temperature and stirred overnight. The solvent was
removed in vacuo, and 20 ml hexane was added. The super-
natant solution was decanted and the residue was sus-
pended with an additional 20 ml of Et2O. A solution of
Me3SiCl (1.85 ml, 14.5 mmol) in Et2O (10 ml) was added
0.05
0.10
0.15
0.20
F2/f
0.25
0.30
Fig. 3. Finemane–Ross plot for ethylene/1-hexene copolymerization.
Table 4
Selected monomer sequence distribution data for some poly(ethylene-co-1-hexene) samplesa
Run
Catalyst
1-Hexeneb (mol%)
Triads sequence distribtuionc
Dyads (%)d
EEE
HEE + EEH
HEH
EHE
HHE + EHH
HHH
EE
EH + HE
HH
3
6
9
14
a
5
6
7
8
24.32
25.11
24.03
23.68
44.04
45.53
47.92
46.60
25.91
24.95
23.56
24.27
5.73
4.41
4.49
5.44
15.36
16.57
15.29
14.71
8.09
7.42
8.05
8.23
0.87
1.12
0.69
0.74
56.99
58.01
59.70
58.73
38.09
37.17
35.59
36.41
4.92
4.83
4.72
4.85
Detailed polymerization conditions see Table 3.
1-Hexene content in copolymer determined by 13C NMR spectra.
Calculated by 13C NMR spectra.
b
c
d
[EE] = [EEE] + 1/2[EEH + HEE], [EH] = [HEH] + [EHE] + 1/2{[EEH + HEE] + [HHE + EHH]}, [HH] = [HHH] + 1/2[HHE + EHH].

1200
T. Xiao et al. / Journal of Organometallic Chemistry 693 (2008) 1195–1202
to the suspension at 0 °C. The resulting mixture was slowly
warmed to room temperature and stirred over night. The
reaction mixture was then filtered and concentrated by
evaporation. Pure product (1.29 g, 40.3%) was obtained
by column chromatography over silica (hexane/ethyl ace-
tate, 10:1) as yellow oil. Anal. Calc. for C28H40OSi2
(448.79): C, 74.94; H, 8.98. Found: C, 74.89; H, 8.95%.
1H NMR (CDCl3, 300 MHz; 298 K): d 6.90–7.36 (m, 8H,
PhH), 6.33–6.50 (m, 3H, CpH), 5.49–5.52 (s, 1H, PhCH),
2.73 mmol) in hexane (30 ml) at À78 °C. The reaction
mixture was allowed to warm to room temperature
and stirred overnight. The precipitate was filtered off,
and the solvent was removed to leave brown oil.
Recrystallization from CH2Cl2/hexane (1:2) gave pure
5 as yellow crystals (0.55 g, 48.4%). Anal. Calc. for
C22H21Cl2OTi (420.17): C, 62.89; H, 5.04. Found: C,
62.78; H, 5.09%. 1H NMR (CDCl3, 300 MHz; 298 K):
d 6.86–7.34 (m, 8H, PhH), 6.06–6.07 (m, 2H, CpH),
5.91–5.92 (m, 2H, CpH), 5.44 (s, 1H, PhCH), 1.48 (s,
9H, tBu). 13C NMR (CDCl3, 75.4 MHz; 298 K): d
160.5, 149.2, 140.4, 137.4, 130.5, 129.9, 129.5, 128.5,
128.5, 126.0, 123.9, 121.5, 120.9, 120.4, 116.8, 39.7,
31.8, 24.9 ppm.
t
3.29–3.32 (1H, m, CpH), 1.40 (s, 9H, Bu), 0.13 (s, 9H,
OSiMe3), 0.02–0.06 (s, 9H, CpSiMe3).
3.3. Preparation of 2-Me3SiC5H4CHPh-4-MeC6H3OSiMe3
(2)
Compound 2 was synthesized using a procedure identi-
cal to that for 1 with 2-bromo-4-metylphenol (1.78 g,
9.53 mmol) as starting material. Pure product (1.65 g,
33.5%) was obtained as yellow oil. Anal. Calc. for
C25H34OSi2 (406.71): C, 73.83; H, 8.43. Found: C, 73.79;
3.7. Preparation of [g5:g1-2-C5H4CHPh-4-MeC6H3O]-
TiCl2 (6)
Complex 6 was synthesized in the same progress as 5
with 2 (1.07 g, 2.63 mmol) as starting material. Pure prod-
uct was obtained as yellow crystals (0.31 g, 31.3%). Anal.
Calc. for C19H15Cl2OTi (378.09): C, 60.36; H, 4.00. Found:
C, 60.25; H, 4.03%. 1H NMR (CDCl3, 300 MHz; 298 K): d
6.80–7.35 (m, 8H, PhH), 6.02–6.03 (m, 2H, CpH), 5.87–
5.88 (m, 2H, CpH), 5.38 (s, 1H, PhCH), 2.26 (s, 9H,
Me). 13C NMR (CDCl3, 75.4 MHz; 298 K): d 160.3,
148.1, 139.6, 136.3, 134.9, 131.6, 130.7, 129.1, 128.7,
127.8, 123.1, 120.8, 120.1, 119.5, 114.3, 46.9 ppm.
1
H, 8.46%. H NMR (CDCl3, 300 MHz; 298 K): d 6.92–
7.30 (m, 8H, PhH), 6.36–6.47 (m, 3H, CpH), 5.48–5.55
(s, 1H, PhCH), 3.26–3.31 (1H, m, CpH), 2.26 (s, 9H,
PhMe), 0.15 (s, 9H, OSiMe3), 0.01–0.07 (s, 9H, CpSiMe3).
3.4. Preparation of 2-Me3SiC5H4CHPh-4-tBuC6H3OSiMe3
(3)
Compound 3 was synthesized using a procedure identi-
cal to that for 1 with 2-bromo-4-tert-butylphenol (2.24 g,
9.76 mmol) as starting material. Pure product (2.14 g,
39.3%) was obtained as yellow oil. Anal. Calc. for
C28H40OSi2 (448.79): C, 74.94; H, 8.98. Found: C, 74.89;
3.8. Preparation of [g5:g1-2-C5H4CHPh-4-tBuC6H3O]
TiCl2 (7)
Complex 7 was synthesized in the same progress as 5
with 3 (1.49 g, 3.32 mmol) as starting material. Pure prod-
uct was obtained as yellow crystals (0.57 g, 40.6%). Anal.
Calc. for C22H21Cl2OTi (420.17): C, 62.89; H, 5.04. Found:
C, 62.78; H, 5.01%. 1H NMR (CDCl3, 300 MHz; 298 K): d
6.82–7.36 (m, 8H, PhH), 6.04–6.05 (m, 2H, CpH), 5.87–
5.88 (m, 2H, CpH), 5.41 (s, 1H, PhCH), 1.23 (s, 9H,
tBu). 13C NMR (CDCl3, 75.4 MHz; 298 K): d 160.7,
148.2, 139.7, 136.6, 129.7, 129.0, 128.7, 127.6, 127.7,
125.1, 123.0, 120.8, 120.1, 119.6, 113.9, 47.2, 34.5,
31.3 ppm.
1
H, 8.94%. H NMR (CDCl3, 300 MHz; 298 K): d 6.91–
7.40 (m, 8H, PhH), 6.38–6.54 (m, 3H, CpH), 5.54–5.56
(s, 1H, PhCH), 3.24–3.30 (1H, m, CpH), 1.27 (s, 9H,
tBu), 0.15 (s, 9H, OSiMe3), 0.01–0.05 (s, 9H, CpSiMe3).
3.5. Preparation of 2-Me3SiC5H4CHPh-4-tBu-
6-tBuC6H2OSiMe3 (4)
Compound 4 was synthesized using a procedure identi-
cal to that for 1 with 2-bromo-4, 6-di-tert-butylphenol
(2.53 g, 8.86 mmol) as starting material. Pure product
(2.25 g, 48.0%) was obtained as yellow oil. Anal. Calc.
for C32H48OSi2 (504.89): C, 76.12, H, 9.58. Found: C,
3.9. [g5:g1-2-C5H4CHPh-4-tBu-6-tBuC6H2O]TiCl2 (8)
1
76.22, H, 9.61%. H NMR (CDCl3, 300 MHz; 298 K): d
Complex 8 was synthesized in the same progress as 5
with 4 (1.31 g, 2.59 mmol) as starting material. Pure prod-
uct was obtained as yellow crystals (0.69 g, 55.7%). Anal.
Calc. for C26H29Cl2OTi (420.17): C, 65.57; H, 6.14. Found:
C, 65.51; H, 6.16%. 1H NMR (CDCl3, 300 MHz; 298 K): d
6.86–7.36 (m, 7H, PhH), 6.05–6.06 (m, 2H, CpH), 5.84–
5.85 (m, 2H, CpH), 5.44 (s, 1H, PhCH), 1.50 (s, 9H,
o-tBu), 1.24 (s, 9H, p-tBu). 13C NMR (CDCl3, 75.4 MHz;
298 K): d 159.9, 147.3, 140.2, 135.0, 134.5, 130.8, 129.0,
128.6, 127.5, 126.3, 123.1, 122.9, 120.6, 119.7, 119.3, 47.7,
35.2, 34.6, 31.3, 30.2 ppm.
6.98–7.34 (m, 7H, Ph), d 6.32–6.45 (m, 3H, CpH), d
5.43–5.48 (s, 1H, Ph–CH), d 2.92–3.01 (1H, m, CpH), d
1.30 (s, 9H, o-tBu), d 1.23 (s, 9H, p-tBu), d 0.27 (s, 9H,
O–Si–Me3), d 0.10–0.11 (s, 9H, Cp–Si–Me3).
3.6. Preparation of [g5:g1-2-C5H4CHPh-6-tBuC6H3O]-
TiCl2 (5)
A solution of 1 (1.21 g, 2.70 mmol) in hexane (20 ml)
was added dropwise to a solution of TiCl4 (0.3 ml,

T. Xiao et al. / Journal of Organometallic Chemistry 693 (2008) 1195–1202
1201
Table 5
Crystal data and structural refinement details for complexes 5 and 8
4. Supplementary material
Complex
5
8
CCDC 669008 and 669007 contain the supplementary
crystallographic data for 5 and 8. These data can be
obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_re-
quest/cif. Supplementary data are available free of charge
from The Director, CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK (fax: +44-1223-336-033: e-mail: depos-
it@ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
Molecular formula
Molecular weight
Crystal system
Space group
C22H22Cl2OTi
421.20
Triclinic
C26H30Cl2OTi
477.30
Orthorhombic
Pbcn
ꢀ
P1
˚
a (A)
9.652(9)
9.716(8)
13.125(10)
97.44(2)
108.35(2)
112.463(17)
1034.9(15)
2
1.352
436
0.679
x–2h
17.513(2)
12.1321(14)
23.578(3)
90
90
90
5009.7(11)
8
1.266
2000
0.569
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
Acknowledgement
3
˚
V (A )
Z
Density (g cmÀ3
)
This work was supported by the National Natural Sci-
ence Foundation of China (Nos. 20674024 and 20772044).
F(000)
Absorption coefficient (mmÀ1
Scan type
)
x–2h
Collected range (°)
Number of reflections
Number of independent
reflections
Rint
Number of data/restraints/
parameters
3.42 6 2h 6 46.50 3.46 6 2h 6 56.78
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