Synthesis, characterization, and ethylene (Co)polymerization behavior of trichlorotitanium 2-(1-(arylimino)propyl)quinolin-8-olates

Article abstract of DOI:10.1002/pola.24617

A series of trichlorotitanium complexes containing 2-(1-(arylimino)propyl) quinolin-8-olates was synthesized by stoichiometric reaction of titanium tetrachloride with the corresponding potassium 2-(1-(arylimino)propyl)quinolin- 8-olates and was fully characterized by elemental analysis, nuclear magnetic resonance spectroscopy, and by single-crystal X-ray diffraction study of representative complexes. All titanium complexes, when activated with methylaluminoxane, exhibited high catalytic activity toward ethylene polymerization [up to 1.15 × 10⁶ g mol^-1(Ti) h ^-1] and ethylene/α-olefin copolymerization [up to 1.54 × 10⁶ g mol^-1 (Ti) h^-1]. The incorporation of comonomer was confirmed to amount up to 2.82 mol % of 1-hexene or 1.94 mol % of 1-octene, respectively. 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 A series of trichlorotitanium 2-(1-(arylimino)propyl)quinolin- 8-olates was synthesized and fully characterized. All titanium complexes, when activated with MAO, exhibited high catalytic activity toward ethylene polymerization and ethylene/α-olefin copolymerization with incorporation of 2.82% for 1-hexene and 1.94% for 1-octene. Copyright

Full text of DOI:10.1002/pola.24617

Synthesis, Characterization, and Ethylene (Co)Polymerization Behavior of
Trichlorotitanium 2-(1-(Arylimino)propyl)quinolin-8-olates
WEI HUANG,1 WENJUAN ZHANG,1 SHAOFENG LIU,1 TONGLING LIANG,1 WEN-HUA SUN1,2
1Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science,
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
2State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics,
Chinese Academy of Sciences, Lanzhou 730000, China
Received 23 November 2010; accepted 29 January 2011
DOI: 10.1002/pola.24617
Published online 1 March 2011 in Wiley Online Library (wileyonlinelibrary.com).
ABSTRACT: A series of trichlorotitanium complexes containing
2-(1-(arylimino)propyl)quinolin-8-olates was synthesized by
stoichiometric reaction of titanium tetrachloride with the corre-
sponding potassium 2-(1-(arylimino)propyl)quinolin-8-olates
and was fully characterized by elemental analysis, nuclear
magnetic resonance spectroscopy, and by single-crystal X-ray
diffraction study of representative complexes. All titanium
complexes, when activated with methylaluminoxane, exhibited
high catalytic activity toward ethylene polymerization [up to
1.15 ꢀ 106 g molꢁ1(Ti) hꢁ1] and ethylene/a-olefin copolymeriza-
tion [up to 1.54 ꢀ 106 g molꢁ1 (Ti) hꢁ1]. The incorporation of
comonomer was confirmed to amount up to 2.82 mol % of
C
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1-hexene or 1.94 mol % of 1-octene, respectively. 2011 Wiley
Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1887–
1894, 2011
KEYWORDS: addition polymerization; 2-(1-(arylimino)propyl)qui-
nolin-8-olates; copolymerization; ethylene homopolymerization;
metal-organic catalysts/organometallic catalysts; polyethylene
(PE); trichlorotitanium pro-catalyst
INTRODUCTION Metallocene pro-catalysts have gained much
attention in practical olefin polymerization because these
catalysts allow the production of fine-designed polyolefins
with controllable molecular weight and dispersity, with spe-
cific tactility, and also with good a-olefins comonomer inclu-
sion.1 As a consequence, half-metallocene pro-catalysts have
been developed to investigate their catalytic behavior in
ethylene polymerization and copolymerization,2 with a view
to the ease of fine-tuning the half-metallocene catalysts
through variation of the anionic derivatives.3 Recently, nor-
mal titanium complexes ligated by amidinate,4 amide,5
and alkoxy6 have been explored extensively in olefin
(co)polymerization, and the well-known representatives are
bis(imino phenolato)titanium (FI catalysts) and bis(imino-
pyrrolido)titanium (PI catalysts) pro-catalysts.7 Using arylo-
nates bearing bridged N-donors as multidentate ligands, the
bis-ligated metal complexes were commonly obtained;8 how-
ever, the trichlorometallic complexes (LMCl3) were difficult
to access and rarely investigated.9 Our trials with multiden-
tate ligands of quinolinolate derivatives illustrated that their
transition metal complexes showed good catalytic activities
in ethylene (co)polymerization,3(d),10 whereas their alumi-
num complexes exhibited high efficiency for the ring-opening
polymerization of e-caprolactone.11
quinolin-8-olate complexes. On treatment with methylalumi-
noxane (MAO), all of these titanium pro-catalysts showed
high activities toward ethylene polymerization and copoly-
merization. The influences of reaction parameters on their
catalytic performance have been investigated in detail.
EXPERIMENTAL
General Considerations
All manipulations of air and/or moisture-sensitive com-
pounds were carried out under nitrogen atmosphere in a
glove box or using standard Schlenk techniques. MAO (1.46
M in toluene) was purchased from Albemarle. Potassium
hydride (KH), purchased from Beijing Reagent Chemicals,
was washed with n-hexane to remove mineral oil before use.
Toluene, n-hexane, and n-heptane were refluxed in the pres-
ence of sodium and benzophenone and distilled under nitro-
gen atmosphere. Dichloromethane (CH2Cl2), 1-hexene, and 1-
octene were dried over calcium hydride and distilled under
nitrogen atmosphere. FTIR spectra were recorded on a
Perkin Elmer FTIR 2000 spectrometer using KBr disc in the
range of 4000–400 cmꢁ1. Elemental analysis was performed
on a Flash EA 1112 microanalyzer. 1H NMR and 13C NMR
spectra were recorded on a Bruker DMX 400 MHz instru-
ment at ambient temperature using tetramethylsilane (TMS)
as an internal standard at 25 ꢂC. 13C NMR spectra of the
In this study, we report on the synthesis and characteriza-
tion of a series of trichlorotitanium 2-(1-(arylimino)propyl)-
polymers were recorded on
a Bruker DMX-300 MHz
Additional Supporting Information may be found in the online version of this article. Correspondence to: W.-H. Sun (E-mail: whsun@iccas.ac.cn)
C
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Journal of Polymer Science Part A: Polymer Chemistry, Vol. 49, 1887–1894 (2011) 2011 Wiley Periodicals, Inc.
POLYMERIZATION BY TRICHLOROTITANIUM COMPLEXES, HUANG ET AL.
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JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
instrument at 110 ꢂC in deuterated 1,2-dichlorobenzene
with TMS as an internal standard. Differential scanning
calorimetry (DSC) trace and melting points of polyethylene
were obtained from the second scanning run on a Perkin-
Elmer DSC-7 at a heating rate of 10 ꢂC minꢁ1. Molecular
weights and polydispersity indices of (co)polyethylenes
were determined by the gel permeation chromatography
(GPC) method using a PL-GPC 220 instrument at 135 ꢂC in
1,2,4-trichlorobenzene with polystyrene as the standard.
(w), 2845 (m), 1635 (CH¼¼N) (s), 1575 (m), 1511 (s), 1421
(s), 1355 (m), 1300 (m), 1246 (m), 1190 (m), 1162 (s), 1076
(m), 934 (s), 852 (s), 799 (m), 752 (w), 721 (m), 665 (w),
592 (w). mp: 118 ꢂC. Anal. Calcd for C23H26N2O: C, 79.73; H,
7.56; N, 8.09. Found: C, 78.99; H, 7.66; N, 7.96.
Synthesis of Trichlorotitanium 2-(1-
(Arylimino)propyl)quinolin-8-olates (C1–C6)
Trichlorotitanium 2-(1-(2,6-Dimethylphenylimino)
propyl)quinolin-8-olate (C1)
To a solution of 0.304 g (1.00 mmol) 2-(1-(2,6-dimethylphe-
nylimino)-propyl)quinolin-8-ol in 30 mL toluene, 0.040 g
(1.00 mmol) KH was added at ꢁ78 ꢂC. The mixture was
stirred for 4 h. After addition of 0.334 g (1.00 mmol)
TiCl4ꢃ(THF)2 at ꢁ78 ꢂC, the mixture was slowly warmed up
to room temperature and stirred for 6 h. After solvent evap-
oration, the residue was extracted with CH2Cl2 (3 ꢀ 20 mL),
and the filtrate was combined and concentrated into about
20 mL. The concentrated solution was covered with n-hep-
tane and kept for 3 days to obtain brown crystals of
trichlorotitanium 2-(1-(2,6-dimethylphenylimino)propyl)qui-
nolin-8-olate (C1) in 0.280 g (61.3%).
Synthesis of 2-(1-(Arylimino)propyl)quinolin-8-ol
Derivatives (L1–L6)
2-(1-(2,6-Dimethylphenylimino)propyl)quinolin-8-ol (L1), 2-
(1-(2,6-diethylphenyl-imino)propyl)quinolin-8-ol (L2), 2-(1-
(2,6-diisopropylphenylimino)propyl)-quinolin-8-ol (L3), and
2-(1-(2,6-dichlorophenylimino)propyl)quinolin-8-ol (L6) were
prepared according to the literature.11 Using the same proce-
dure, the two new compounds L4 and L5 were synthesized.
2-(1-(Mesitylimino)propyl)quinoline-8-ol (L4)
The mixture of 0.402 g (2.0 mmol) 1-(8-hydroxyquinoline-2-
yl)propan-1-one, 0.324 g (2.4 mmol) 2,4,6-trimethylaniline,
and a catalytic amount of p-toluenesulfonic acid (0.10 g) in
20 mL toluene was refluxed for 24 h. After toluene evapora-
tion, 2-(1-(mesitylimino)propyl)quinoline-8-ol (L4) was puri-
fied on column chromatography (silica gel, petroleum ether/
ethyl acetate ¼ 20:1) and was obtained as a yellow green
solid in 0.271 g (42.6%).
1H NMR (CDCl3, 400 MHz, ppm): 8.69 (d, J ¼ 8.1 Hz, 1H,
quino-H), 8.00 (d, J ¼ 8.6 Hz, 1H, quino-H), 7.89 (t, J ¼ 8.4
Hz, 1H, quino-H), 7.72 (d, J ¼ 8.4 Hz, 1H, quino-H), 7.25 (d, J
¼ 8.1 Hz, 1H, quino-H), 7.15 (d, J ¼ 8.0 Hz, 2H, Ar-H), 7.04
(t, J ¼ 7.8 Hz, 1H, Ar-H), 2.92–2.86 (m, J ¼ 7.9 Hz, 2H,
N¼¼CCH2CH3), 2.54 (s, 6H, Ar-CH3), 1.26 (t, J ¼ 7.3 Hz, 3H,
N¼¼CCH2CH3). 13C NMR (CDCl3, 100 MHz, ppm): d 179.3
(CH¼¼N), 163.4, 145.0, 141.3, 133.7, 131.3, 129.8, 129.5,
129.2, 128.8, 128.4, 125.5, 120.6, 111.8, 25.2, 21.3, 19.5,
11.9. Anal. Calcd for C20H19Cl3N2OTi: C, 52.49; H, 4.19; N,
6.12. Found: C, 52.38; H, 4.11; N, 6.33.
1H NMR (CDCl3, 400 MHz, ppm): d 8.50 (d, J ¼ 8.5 Hz, 1H,
quino-H), 8.26 (d, J ¼ 8.2 Hz, 1H, quino-H), 8.15 (s, 1H, OH),
7.51 (t, J ¼ 7.4 Hz, 1H, quino-H), 7.40 (d, J ¼ 7.6 Hz, 1H,
quino-H), 7.23 (d, J ¼ 7.1 Hz, 1H, quino-H), 6.91 (s, 2H, Ar-H),
2.81–2.77 (m, 2H, N¼¼CCH2CH3), 2.31 (s, 3H, Ar-CH3), 2.04 (s,
6H, Ar-CH3), 1.08 (t, J ¼ 7.3 Hz, 3H, N¼¼CCH2CH3). 13C NMR
(CDCl3, 100 MHz, ppm): d 171.3 (CH¼¼N), 155.2, 153.4, 152.5,
146.0, 136.7, 132.5, 129.1, 128.8, 128.7, 125.1, 120.5, 118.0,
110.4, 23.1, 20.1, 18.2, 11.7. IR (KBr, cmꢁ1): 3415 (OAH) (w),
3004 (m), 1634 (CH¼¼N) (m), 1526 (s), 1443 (m), 1256 (m),
1210 (m), 1041 (m), 1027 (s), 852 (m), 797 (m), 768 (w),
710 (m), 520 (w). mp: 82 ꢂC. Anal. Calcd for C21H22N2O: C,
79.21; H, 6.96; N, 8.80. Found: C, 79.23; H, 7.04; N, 8.76.
Trichlorotitanium 2-(1-(2,6-Diethylphenylimino)
propyl)quinolin-8-olate (C2)
Using the same procedure as for the synthesis of C1, C2 was
prepared by using L2 instead of L1 as brown crystals in
1.22 g (86.5%).
1H NMR (CDCl3, 400 MHz, ppm): d 8.69 (d, J ¼ 8.3 Hz, 1H,
quino-H), 8.06 (d, J ¼ 8.3 Hz, 1H, quino-H), 7.91 (t, J ¼ 8.0
Hz, 1H, quino-H), 7.71 (d, J ¼ 8.2 Hz, 1H, quino-H), 7.25 (d, J
¼ 8.1 Hz, 1H, quino-H), 7.12 (d, J ¼ 7.3 Hz, 2H, Ar-H), 7.04
(t, J ¼ 7.8 Hz, 1H, Ar-H), 3.14–3.08 (m, 2H, N¼¼CCH2CH3),
2.88–2.86 (m, 2H, Ar-CH2CH3), 2.67–2.61 (m, 2H, Ar-
CH2CH3), 1.36 (t, J ¼ 7.5 Hz, 6H, Ar-CH2CH3), 1.29 (t, J ¼ 7.2
Hz, 3H, N¼¼CCH2CH3). 13C NMR (CDCl3, 100 MHz, ppm): d
178.5 (CH¼¼N), 154.2, 153.6, 141.4, 138.9, 137.7, 131.3,
129.6, 129.3, 128.9, 124.2, 121.8, 118.8, 111.2, 24.9, 23.7,
13.9, 11.6. Anal. Calcd for C22H23Cl3N2OTi: C, 54.41; H, 4.77;
N, 5.77. Found: C, 54.18; H, 4.82; N, 6.13.
2-(1-(2,6-Diethyl-4-methylphenylimino)propyl)
quinoline-8-ol (L5)
Using the same procedure, 2-(1-(2,6-diethyl-4-methylphenyli-
mino)propyl)quinolin-8-ol (L5) was isolated as an orange
yellow solid in 43.2% yield (0.298 g).
1H NMR (CDCl3, 400 MHz, ppm): d 8.47 (d, J ¼ 8.6 Hz, 1H,
quino-H), 8.24 (d, J ¼ 8.3 Hz, 1H, quino-H), 8.16 (s, 1H, OH),
7.50 (t, J ¼ 7.9 Hz, 1H, quino-H), 7.39 (d, J ¼ 8.2 Hz, 1H,
quino-H), 7.23 (d, J ¼ 7.8 Hz, 1H, quino-H), 6.94 (s, 2H, Ar-H),
2.83–2.77 (m, 2H, N¼¼CCH2CH3), 2.45–2.37 (m, 2H, Ar-
CH2CH3), 2.32–2.26 (m, 2H, Ar-CH2CH3), 2.34 (s, 3H, Ar-CH3),
1.17 (t, J ¼ 7.5 Hz, 6H, Ar-CH2CH3), 1.07 (t, J ¼ 7.4 Hz, 3H,
N¼¼CCH2CH3). 13C NMR (CDCl3, 100 MHz, ppm): d 170.7
(CH¼¼N), 153.5, 152.5, 145.0, 137.1, 136.7, 132.6, 130.8, 129.0,
128.8, 126.7, 120.5, 118.0, 110.4, 24.7, 23.3, 21.4, 13.7, 11.6.
IR (KBr, cmꢁ1): 3440 (OAH) (m), 3042 (m), 2964 (m), 2917
Trichlorotitanium 2-(1-(2,6-Diisopropylphenylimino)
propyl)quinolin-8-olate (C3)
Using the same procedure as for the synthesis of C1, C3 was
formed as brown solid in 1.62 g (89.6%).
1H NMR (CDCl3, 400 MHz, ppm): d 8.58 (d, J ¼ 8.6 Hz, 1H,
quino-H), 8.00 (d, J ¼ 8.6 Hz, 1H, quino-H), 7.93 (t, J ¼ 8.4
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ARTICLE
Hz, 1H, quino-H), 7.53 (d, J ¼ 8.0 Hz, 1H, quino-H), 7.19 (t,
J ¼ 7.2 Hz, 1H, quino-H), 7.01 (d, J ¼ 7.7 Hz, 2H, Ar-H), 6.95
(t, J ¼ 7.8 Hz, 1H, Ar-H), 3.39–3.33 (m, 2H, Ar-CH(CH3)2),
2.91–2.86 (m, 2H, N¼¼CCH2CH3), 1.30 (d, J ¼ 6.5 Hz, 6H, Ar-
CH(CH3)2), 1.26 (d, J ¼ 7.5 Hz, 6H, Ar-CH(CH3)2), 1.21 (t, J ¼
6.8 Hz, 3H, N¼¼CCH2CH3). 13C NMR (CDCl3, 100 MHz, ppm):
d 178.9 (CH¼¼N), 164.1, 143.9, 141.6, 139.6, 130.4, 129.2,
128.4, 128.2, 125.4, 124.6, 120.6, 117.2, 112.4, 29.8, 28.6,
25.4, 24.0, 21.6, 12.3. Anal. Calcd for C24H27Cl3N2OTi: C,
56.11; H, 5.30; N, 5.45. Found: C, 56.04; H, 5.54; N, 5.23.
X-Ray Structure Determination
Crystals of C1 and C6 suitable for single-crystal X-ray analy-
sis were obtained by overlaying their CH2Cl2 solutions with
n-heptane. Single-crystal X-ray diffraction for C1 and C6
were performed on a Rigaku RAXIS Rapid IP diffractometer
with graphite-monochromated Mo Ka radiation (k ¼ 0.71073
Å) at 173(2) K. Cell parameters are obtained by global
refinement of the positions of all collected reflections. Inten-
sities are corrected for Lorentz and polarization effects and
empirical absorption. The structures are solved by direct
methods and refined by full-matrix least-squares on F2. All
nonhydrogen atoms are refined anisotropically. Structure so-
lution and refinement are performed by using the SHELXL-
97 package.12 Crystal data collection and refinement details
are given in Table 1. CCDC 801330 (C1) and 801331 (C6)
are given in the Supporting Information crystallographic
data, which could be obtained free of charge from the Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Trichlorotitanium 2-(1-(Mesitylimino)propyl)quinolin-
8-olate (C4)
Using the same procedure as for the synthesis of C1, C4 was
isolated as a brown solid in 1.37 g (63.7%).
1H NMR (CDCl3, 400 MHz, ppm): d 8.70 (d, J ¼ 8.5 Hz, 1H,
quino-H), 8.07 (d, J ¼ 8.3 Hz, 1H, quino-H), 7.89 (t, J ¼ 8.0
Hz, 1H, quino-H), 7.71 (d, J ¼ 7.5 Hz, 1H, quino-H), 7.27 (d, J
¼ 7.5 Hz, 1H, quino-H), 7.02 (s, 2H, Ar-H), 2.89–2.84 (m, 2H,
N¼¼CCH2CH3), 2.49 (s, 3H, Ar-CH3), 2.37 (s, 6H, Ar-CH3), 1.34
(t, J ¼ 7.8 Hz, 3H, N¼¼CCH2CH3). 13C NMR (CDCl3, 100 MHz,
ppm): d 179.3 (CH¼¼N), 155.7, 154.1, 153.2, 146.9, 137.2,
133.6, 129.9, 129.2, 129.2, 125.9, 121.5, 118.7, 111.7, 23.4,
20.6, 18.3, 11.8. Anal. Calcd for C21H21Cl3N2OTi: C, 53.48; H,
4.49; N, 5.94. Found: C, 53.62; H, 4.59; N, 5.71.
Procedures for Ethylene Polymerization
and Copolymerization
A stainless steel autoclave (0.5 L) equipped with a mechani-
cal stirrer and a temperature controller was heated in vac-
ꢂ
uum at 80 C, recharged with ethylene three times, and then
cooled to room temperature under ethylene atmosphere. A
toluene solution of the titanium pro-catalyst (with comono-
mer) was transferred into the reactor. After the desired reac-
tion temperature was reached and the required amount of
cocatalyst (with 100 mL volume in total) was added, the
autoclave was immediately pressurized to 10 atm. The ethyl-
ene pressure was kept constant during the reaction through
feeding ethylene. After a due time, the feeding ethylene was
stopped, and the autoclave was placed in a water-ice bath
for 1 h in order to be cooled. The resultant mixture was
poured into a 10% HCl–ethanol solution. The solid polymer
was collected, washed with water and ethanol several times,
and dried under vacuum to constant weight.
Trichlorotitanium 2-(1-(2,6-Diethyl-4-methylphenylimino)-
propyl)quinolin-8-olate (C5)
Using the same procedure as for the synthesis of C1, C5 was
observed as a brown solid in 2.05 g (72.2%).
1H NMR (CDCl3, 400 MHz, ppm): d 8.69 (d, J ¼ 8.6 Hz, 1H,
quino-H), 8.06 (d, J ¼ 8.2 Hz, 1H, quino-H), 7.08 (t, J ¼ 7.9
Hz, 1H, quino-H), 7.71 (d, J ¼ 8.2 Hz, 1H, quino-H), 7.25 (d, J
¼ 8.1 Hz, 1H, quino-H), 7.04 (s, 2H, Ar-H), 3.14–3.08 (m, 2H,
N¼¼CCH2CH3), 2.88–2.86 (m, 2H, Ar-CH2CH3), 2.67–2.61 (m,
2H, N¼¼CCH2CH3), 2.40 (s, 3H, Ar-CH3), 1.36 (t, J ¼ 7.8 Hz,
3H, N¼¼CCH2CH3), 1.29 (t, J ¼ 7.14 Hz, 6H, Ar-CH2CH3). 13C
NMR (CDCl3, 100 MHz, ppm): d 178.5 (CH¼¼N), 154.2, 153.5,
147.9, 137.6, 137.1, 131.3, 129.2, 130.7, 126.3, 123.8, 120.9,
118.4, 111.3, 24.4, 23.7, 18.3, 13.7, 11.7. Anal. Calcd for
RESULTS AND DISCUSSION
Synthesis and Characterization of Trichlorotitanium
2-(1-(Arylimino)propyl)quinolin-8-olates (C1–C6)
We used metal-chloride exchange in our previous syntheses
of titanium complexes,13 and this approach allowed for the
preparation of the complexes C1–C6 in moderate to good
yields (59.4–89.6%) by stoichiometric reaction of
TiCl4ꢃ(THF)2 with the corresponding potassium 2-(1-(aryli-
mino)propyl)quinolin-8-olates in toluene (Scheme 1). The
elemental analyses are fully consistent with the molecular
formula LTiCl3.
C23H25Cl3N2OTi: C, 55.28; H, 5.04; N, 5.61. Found: C, 55.53;
H, 4.91; N, 5.46.
Trichlorotitanium 2-(1-(2,6-Dichlorophenylimino)propyl)-
quinolin-8-olate (C6)
Using the same procedure as for the synthesis of C1, C6 was
produced as a brown solid and recrystallized in CH2Cl2 lay-
ing 1-heptane to form brown crystals in 1.54 g (59.4%). d
8.71 (d, J ¼ 8.5 Hz, 1H, quino-H), 8.12 (d, J ¼ 8.2 Hz, 1H,
quino-H), 7.91 (t, J ¼ 7.8 Hz, 1H, quino-H), 7.72 (d, J ¼ 7.4
Hz, 1H, quino-H), 7.22 (d, J ¼ 7.2 Hz, 1H, quino-H), 7.02 (d, J
¼ 7.5 Hz, 2H, Ar-H), 6.98 (t, J ¼ 7.4 Hz, 1H, Ar-H), 3.01–2.96
(m, 2H, N¼¼CCH2CH3), 1.46 (t, J ¼ 7.6 Hz, 3H, N¼¼CCH2CH3).
13C NMR (CDCl3, 100 MHz, ppm): d 179.7 (CH¼¼N), 154.3,
153.7, 150.1, 138.9, 137.1, 132.7, 131.7, 128.8, 128.1, 127.7,
123.5, 121.8, 113.4, 21.7, 11.6. Anal. Calcd for
The peaks of the hydroxyl groups in the free ligands appear
at about 8.1 ppm in the 1H NMR spectra. These peaks dis-
appear during the formation of their titanium complexes as
phenols are deprotonated before the formation of TiAO
bonds. The complexation can also be monitored in the 13C
NMR spectra as the CH¼¼N resonances of the bound ligands
appear around 178–180 ppm, and they are shifted downfield
by 8–9 ppm when compared with the free ligands.
C18H13Cl5N2OTi: C, 43.37; H, 2.63; N, 5.62. Found: C, 43.61;
H, 2.55; N, 5.58.
POLYMERIZATION BY TRICHLOROTITANIUM COMPLEXES, HUANG ET AL.
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JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
TABLE 1 Crystallographic Data and Refinement Details for Complexes C1 and C6
C1
C6
Empirical formula
Formula weight
Crystal color
C20H19Cl3N2OTi
457.62
C18H13Cl5N2OTi
498.45
Red
Red
Temperature (K)
173(2)
173(2)
˚
Wavelength (A)
0.71073
0.71073
Crystal system
Space group
Monoclinic
P2(1)/n
Triclinic
P-1
˚
a (A)
12.425(3)
14.117(3)
13.289(3)
90
8.1176(16)
10.646(2)
15.062(3)
97.25(3)
˚
b (A)
˚
c (A)
a (ꢂ)
b (ꢂ)
92.64(3)
98.63(3)
c (ꢂ)
90
112.25(3)
1166.9(4)
2
3
˚
Volume (A )
2328.6(8)
4
Z
Dcalc (mg mꢁ3
)
1.305
1.419
l (mmꢁ1
)
0.723
0.949
F(000)
936
500
Crystal size (mm)
h range (ꢂ)
0.20 ꢀ 0.10 ꢀ 0.09
2.11–27.48
16 ꢄ h ꢄ 16
ꢁ18 ꢄ k ꢄ 17
ꢁ16 ꢄ l ꢄ 17
18,698
0.46 ꢀ 0.21 ꢀ 0.09
1.40–27.46
ꢁ10 ꢄ h ꢄ 10
ꢁ13 ꢄ k ꢄ 13
ꢁ19 ꢄ l ꢄ 19
14,288
Limiting indices
Number of reflections collected
Number of unique reflections
Rint
5337
5319
0.0689
0.0434
Completeness to h (%)
Goodness-of-fit on F2
Final R indices [I > 2r (I)]
99.8 (h ¼ 27.48)
1.157
99.3(h ¼ 27.46)
1.086
R1 ¼ 0.0750
wR2 ¼ 0.2091
R1 ¼ 0.0989
wR2 ¼ 0.2118
0.368, ꢁ0.479
R1 ¼ 0.0520
wR2 ¼ 0.1376
R1 ¼ 0.0627
wR2 ¼ 0.1453
0.42, ꢁ0.421
R indices (all data)
ꢁ3
˚
Largest diff peak, hole (e A
)
SCHEME 1 Synthesis of tita-
nium complexes C1–C6.
1890
WILEYONLINELIBRARY.COM/JOURNAL/JPOLA

ARTICLE
˚
TABLE 2 Selected Bond Lengths (A) and Bond Angles (8)
for C1 and C6
C1
C6
˚
Bond lengths (A)
Ti(1)AO(1)
1.868(3)
1.871(2)
Ti(1)AN(1)
2.108(4)
2.117(2)
Ti(1)AN(2)
2.283(4)
2.265(3)
Ti(1)ACl(1)
2.2763(15)
2.2922(14)
2.3550(16)
2.2736(10)
2.3098(11)
2.3157(11)
Ti(1)ACl(2)
Ti(1)ACl(3)
FIGURE 1 Molecular structure of C1 (ellipsoids enclose 30%
Bond angles (ꢂ)
O(1)ATi(1)AN(1)
O(1)ATi(1)AN(2)
N(1)ATi(1)AN(2)
O(1)ATi(1)ACl(1)
N(1)ATi(1)ACl(1)
N(2)ATi(1)ACl(1)
O(1)ATi(1)ACl(2)
N(1)ATi(1)ACl(2)
N(2)ATi(1)ACl(2)
Cl(1)ATi(1)ACl(2)
O(1)ATi(1)ACl(3)
N(1)ATi(1)ACl(3)
N(2)ATi(1)ACl(3)
Cl(1)ATi(1)ACl(3)
Cl(2)ATi(1)ACl(3)
electronic density; H atoms are omitted for clarity).
77.62(14)
148.06(14)
70.49(14)
106.89(11)
173.23(11)
105.03(11)
92.81(11)
90.52(11)
85.98(11)
94.26(6)
77.24(10)
147.09(9)
69.88(9)
107.19(7)
175.00(7)
105.72(7)
93.49(8)
89.02(7)
84.69(7)
92.98(4)
90.41(8)
82.90(7)
87.05(7)
94.63(4)
170.03(4)
To clarify the absolute molecular structure, two representa-
tive complexes C1 and C6 were measured by the single-crys-
tal X-ray diffraction. The molecular structures are illustrated
in Figures 1 and 2, and the selected bond lengths and bond
angles are tabulated in Table 2.
The structural features of complexes C1 and C6 are rather
similar, and therefore, the structure of complex C1 is dis-
cussed. Figure 1 shows that titanium is coordinated by one
tridentate ligand and three chlorine atoms, adopting a dis-
torted octahedral geometry with O1, N1, N2, and Cl1 in the
base plane and two more chlorines (Cl2 and Cl3) located in
trans-apical positions and enclosing an Cl(3)ATi(1)ACl(2)
angle of 171.54(6)ꢂ. The 2-(1-(2,6-dimethylphenylimino)pro-
pyl)quinolin-8-olate is located around the titanium center in
a meridianal manner (N^N^O). The phenyl ring of the Schiff
base moiety is twisted out of the coordination plane with
the dihedral angle of 73.1ꢂ. The similar conformational phe-
nomenon was observed in the aluminum analogs.11 The
angles ff(N1ATi1AN2) and ff(O1ATi1AN1) are 70.49ꢂ and
77.62ꢂ, respectively, and their sum of 148.1ꢂ is identical to
the angle ff(O1ATi1AN2). The bond distances TiACl
(2.2763–2.3550 Å) are similar to those in the reported tita-
nium complexes.9(c) The TiAN bonds (Ti1AN1: 2.108(4) Å,
Ti1AN2: 2.283(4) Å) are also in the common range with
slight difference due to the nature of ligands.
89.75(11)
82.15(11)
87.59(11)
92.71(6)
171.54(6)
cocatalysts such as AlMe3, AlEt3, EtAlCl2, and Et2AlCl failed,
pro-catalyst C3 showed good activity in ethylene polymeriza-
tion with MAO and MAO. With the molar Al/Ti ratio of 1500
at 20 ꢂC within 30 min, we measured activities of 2.80 ꢀ
105 g molꢁ1(Ti) hꢁ1 for MAO and of 2.19 ꢀ 105 g molꢁ1(Ti)
hꢁ1 for MMAO, and detailed investigations were conducted
using MAO as cocatalyst (entries 1–8, Table 3). By variation
of the molar Al/Ti ratio at 20 ꢂC, the maximal activity of
1.06 ꢀ 106 g molꢁ1(Ti) hꢁ1 was achieved at the Al/Ti ratio
of 5000, and an optimum ratio of Al/Ti for titanium catalytic
systems was often observed.14 The catalytic activities were
slightly affected by the reaction temperature, and the opti-
mum value of 1.16 ꢀ 106 g molꢁ1(Ti) hꢁ1 was realized at
60 ꢂC (entries 3 and 6–8, Table 3), a value which agrees
closely with traditional FI catalysts.15 Increasing tempera-
tures led to a decrease of molecular weights from 389 kg
Catalytic Behavior for Ethylene Polymerization
The pro-catalyst C3 was used in the selection of a suitable
cocatalyst. Although the combination with alkylaluminum
molꢁ1 at 40 C to 266 kg mol at 80 C. This temperature
dependence is in line with the expected increase of chain
transfers and terminations at elevated temperatures. The
DSC analysis corroborated that the polyethylenes with the
melting points from 131.3 ꢂC to 138.7 ꢂC are high-density
polyethylenes.
ꢁ1
ꢂ
ꢂ
The performances of the other pro-catalysts were extensively
studied with the reaction conditions that involve an Al/Ti ra-
tio of 5000 at 60 ꢂC within 30 min (entries 9–13, Table 3).
FIGURE 2 Molecular structure of C6 (ellipsoids enclose 30%
electronic density; H atoms are omitted for clarity).
POLYMERIZATION BY TRICHLOROTITANIUM COMPLEXES, HUANG ET AL.
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JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
TABLE 3 Ethylene Polymerization Results by C1–C6/MAO Systemsa
Activity [105 g molꢁ1
Mw (105
g
b
b
c
Entry
Complexes
Al/Ti
T (ꢂC)
Polymer (g)
(Ti) hꢁ1
]
molꢁ1
)
Mw/Mn
Tm (ꢂC)
1
C3
C3
C3
C3
C3
C3
C3
C3
C1
C2
C4
C5
C6
3,000
4,000
5,000
6,000
7,000
5,000
5,000
5,000
5,000
5,000
5,000
5,000
5,000
20
20
20
20
20
40
60
80
60
60
60
60
60
1.27
1.40
2.66
1.92
1.40
2.74
2.88
1.24
0.540
0.830
1.24
1.84
1.88
5.10
5.60
10.6
7.70
5.60
11.0
11.5
5.00
2.20
4.20
5.00
7.40
7.60
b
3.85
3.72
3.69
3.63
3.56
3.39
3.17
2.66
3.38
3.32
2.47
1.88
2.62
12.4
13.2
15.9
26.9
32.4
16.9
17.7
20.8
10.2
12.1
16.2
13.4
15.1
138.7
138.4
138.0
137.7
135.3
133.3
132.0
131.7
132.0
132.7
131.3
132.7
132.7
2
3
4
5
6
7
8
9
10
11
12
13
a
Conditions: 5 lmol Ti, total volume 100 mL toluene, 30 min, 10 atm
Determined by GPC.
Determined by DSC.
c
ethylene.
The catalytic activities follow the order C3 (iPr) > C2 (Et) >
C1 (Me) (entries 3, 9, and 10, Table 3), and hence, the bulk-
ier substituent on the ortho-position of the aryl group
appears to enhance the active species and to result in a
higher activity.7(b) The solubilities of the complexes (C1-C3)
follow the order of C3 (iPr) > C2 (Et) > C1 (Me) and might
well affect that observed catalytic activities. Solubility effects
on the activities of pro-catalysts are also reflected by the
results obtained with ligands with an additional para-methyl
in pro-catalysts C4 and C5: C4 (2,4,6-trimethylphenyl) > C1
(2,6-dimethylphenyl) and C5 (2,6-diethyl-4-methylphenyl) >
C2 (2,6-diethylphenyl). Moreover, electron-donating ligands
are expected to be advantageous for the stabilization of elec-
tron-deficient titanium complexes and to result in better acti-
vities,7(b),16 and this expectation is borne out by the general
observations of the title titanium pro-catalysts. In compari-
son to the catalytic systems of CpTiCl3/MAO,3(e) the pro-cata-
lysts described here exhibit higher activity in ethylene poly-
merization. This result suggests that the bulky multidentate
ligands stabilize the active species better than the Cp group.
The wide molecular distributions of the polyethylenes sug-
gest that the catalytic systems comprise many different
TABLE 4 Copolymerization of Ethylene with 1-Olefin by C1–C6/MAOa
Activity [105
g
Mw (105
g
b
b
c
Entry
Complex
Monomer
Polymer (g)
molꢁ1 (Ti) hꢁ1
]
molꢁ1
)
Mw/Mn
Tm (ꢂC)
¼
1
C3
C3
C3
C1
C2
C4
C5
C6
C1
C2
C3
C4
C5
C6
0.05M C6
0.280
0.272
0.104
0.162
0.223
0.391
0.254
0.242
0.074
0.096
0.122
0.144
0.074
0.052
11.2
10.9
4.16
6.48
8.92
15.6
11.6
9.53
2.89
3.84
4.88
5.76
2.96
2.08
b
3.34
4.22
2.39
2.21
6.09
2.69
2.37
5.07
5.77
2.45
2.26
2.69
2.10
2.64
19.0
14.2
10.4
19.4
15.8
13.2
11.6
12.1
23.6
21.4
21.2
18.9
16.5
15.5
133.7
130.3
127.0
130.7
130.4
128.0
129.3
124.7
131.7
130.7
129.3
130.0
130.0
130.7
¼
2
0.1M C6
¼
3
0.3M C6
¼
4
0.1M C6
¼
5
0.1M C6
¼
6
0.1M C6
¼
7
0.1M C6
¼
8
0.1M C6
¼
9
0.1M C8
¼
10
11
12
13
14
a
0.1M C8
¼
0.1M C8
¼
0.1M C8
¼
0.1M C8
¼
0.1M C8
Condition: 1 lmol complex, Al/Ti ¼ 5000, toluene (total volume 100
Determined by GPC.
Determined by DSC.
c
mL), 15 min, 60 ꢂC, 10 atm.
1892
WILEYONLINELIBRARY.COM/JOURNAL/JPOLA

ARTICLE
active species. We envision that the presence of three chlor-
ides adopting mer-coordination in the pro-catalysts allow for
the formations of a variety of active species by abstraction of
varying numbers of chlorine ligands and their replacement
with MAO species.
Ethylene/1-Hexene and Ethylene/
1-Octene Copolymerization
The trichlorotitanium pro-catalysts provide more space around
the active center, and one is naturally led to consider whether
this might be beneficial for the fabrication of branched poly-
ethylene. Therefore, we explored the copolymerization of eth-
ylene with a-olefins with the current catalytic systems. The
optimum reaction condition with an Al/Ti ratio of 5000 at
ꢂ
60 C within 30 min was used in exploring the suitable con-
¼
centration of 1-hexene (C6 ) using C3 (entries 1–3, Table 4).
We observed a decrease in the catalytic activities as the como-
nomer concentration increased, and this phenomenon is com-
monly observed with half-titanocene imino-indolate and half-
titanocene amidate.3(b,c) By balancing the incorporation of
comonomer and catalytic performance, the concentration of
FIGURE 4 13C NMR spectrum of ethylene/1-octene copolymer
by the C4/MAO system (entry 12 in Table 4).
¼
comonomer was fixed as 0.1 M for both 1-hexene (C6 ) and 1-
¼
octene (C8 ) at initial toluene solution. All pro-catalysts C1–C6
copolymers when compared with the polyethylenes produced
by homopolymerization of ethylene. To clarify the incorpora-
tion of a-olefins, 13C NMR measurement was used to check the
representative copolymers by C4/MAO system. The 13C NMR
spectrum of the ethylene/1-hexene copolymer (entry 6, Table
4) is shown in Figure 3. The spectrum shows the typical char-
acteristics of linear low-density polyethylene17 and indicated
the incorporation of 2.82 mol % of 1-hexene. The monomer
sequence distributions determined by the 13C NMR spectrum
showed that the obtained poly(ethylene-1-hexene) contained
isolated 1-hexene units (HHH), (EEE)n, EHE, EHH, HEH, HEEH,
EEEH, EEHE þ EEHH, and so forth.18
showed high catalytic activities toward the copolymerization
of ethylene with either 1-hexene or 1-octene (Table 4).
The data in Table 4 show that the pro-catalysts exhibit better
activities with 1-hexene than with 1-octene. With reference
to the data in Table 3, a positive ‘‘comonomer effect’’ occurs
in the copolymerization of ethylene with 1-hexene (Table 4),
whereas a negative comonomer effect was observed in the
copolymerization of ethylene with 1-octene (Table 4). There-
fore, the title pro-catalysts are promising for applications in
the copolymerization of ethylene with 1-hexene.
The DSC analysis showed lower melting points for all copoly-
mers, and this result is indicative of effective incorporation
of a-olefins. The GPC data showed slightly lower molecular
weights and wider molecular distributions of the obtained
In addition, the 13C NMR spectrum (Fig. 4) of ethylene/1-
octene copolymer (entry 12, Table 4) indicates a 1.94 mol %
incorporation of 1-octene in the resulting polymer.
CONCLUSIONS
The trichlorotitanium 2-(1-(arylimino)propyl)quinolin-8-
olates (C1–C6) were designed, synthesized, and fully charac-
terized. All titanium pro-catalysts demonstrated high activ-
ities toward ethylene polymerization and copolymerization.
The mer-coordination of three chlorides provides more space
around active center, leads to the formation of a variety of
active species, and results in the production of polymers
with wide molecular weight distributions. The positive como-
nomer effect was observed in the copolymerization with 1-
hexene, whereas a negative comonomer effect was found in
the copolymerization of ethylene with 1-octene. The catalytic
activities toward ethylene polymerization varied in the order
C3 (R1 ¼ iPr, R2 ¼ H) > C6 (R1 ¼ Cl, R2 ¼ H) > C5 (R1
¼
Et, R2 ¼ Me) > C4 (R1 ¼ R2 ¼ Me) > C2 (R1 ¼ Et, R2 ¼ H)
> C1 (R1 ¼ Me, R2 ¼ H). This ordering indicates that
the catalytic activity of the electron-deficient titanium
pro-catalysts is enhanced by bulky, electron-donating alkyl
substituents. Considerable incorporation of comonomers was
FIGURE 3 13C NMR spectrum of ethylene/1-hexene copolymer
by the C4/MAO system (entry 6 in Table 4).
POLYMERIZATION BY TRICHLOROTITANIUM COMPLEXES, HUANG ET AL.
1893

JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
7 (a) Matsui, S.; Tohi, Y.; Mitani, M.; Saito, J.; Makio, H.;
Tanaka, H.; Nitabaru, M.; Nakano, T.; Fujita, T. Chem Lett 1999,
1065–1066; (b) Tian, J.; Coates, G. W. Angew Chem Int Ed Engl
2000, 39, 3626–3629; (c) Makio, H.; Kashiwa, N.; Fujita, T. Adv
Synth Catal 2002, 344, 477–493; (d) Edson, J. B.; Wang, Z. G.;
Kramer, E. J.; Coates, G. W. J Am Chem Soc 2008, 130,
4968–4977; (e) Tian, J.; Hustad, P. D.; Coates, G. W. J Am
Chem Soc 2001, 123, 5134–5135; (f) Matsui, S.; Mitani, M.;
Saito, J.; Tohi, Y.; Makio, H.; Matsukawa, N.; Takagi, Y.; Tsuru,
K.; Nitabaru, M.; Nakano, T.; Tanaka, H.; Kashiwa, N.; Fujita, T.
J Am Chem Soc 2001, 123, 6847–6856; (g) Sakuma, A.; Weiser,
M. S.; Fujita, T. Polym J 2007, 39, 193–207.
achieved with 2.82 mol % of 1-hexene or 1.94 mol % of 1-
octene, respectively.
This work is supported by Natural Science Foundation of China
(NSFC) (nos. 20874105 and 20904059) and the Ministry
of Science and Technology (MOST) 863 Program (no.
2009AA034601). The authors are grateful to Rainer Glaser
(Department of Chemistry, University of Missouri-Columbia,
Columbia, MO) for proofreading the English language.
REFERENCES AND NOTES
1 (a) Sinn, H.; Kaminsky, W. Adv Organomet Chem 1980, 18,
99–112; (b) Sinn, H.; Kaminsky, W.; Vollmer, H. J.; Woldt, R.
Angew Chem Int Ed Engl 1980, 19, 390–392; (c) Brintzinger, H.
8 (a) Lian, T. B.; Spaniol, T. P.; Okuda, J. Organometallics 2007,
26, 6653–6660; (b) Janas, Z.; Jerzykiewicz, L. B.; Przybylak, K.;
Sobota, P.; Szczegot, K. Eur J Inorg Chem 2004, 1639–1645; (c)
H.; Fischer, D.; Mulhaupt, R.; Rieger, B.; Waymouth, R. M.
¨
Capacchione, C.; Proto, A.; Ebeling, H.; Mulhaupt, R.; Moller, K.;
¨
Angew Chem Int Ed Engl 1995, 34, 1143–1170; (d) McKnight, A.
L.; Waymouth, R. M. Chem Rev 1998, 98, 2587–2598; (e) Alt, H.
Spaniol, T. P.; Okuda, J. J Am Chem Soc 2003, 125, 4964–4965;
(d) Capacchione, C.; Proto, A.; Okuda, J. J Polym Sci Part A:
Polym Chem 2004, 42, 2815–2822; (e) Hu, W.; Sun, X.; Wang, C.;
Gao, Y.; Tang, Y.; Shi, L.; Xia, W.; Sun, J.; Dai, H.; Li, X.; Yao, X.;
Wang, X. Organometallics 2004, 23, 1684–1688; (f) Wang, C.;
Sun, X.; Guo, Y.; Gao, Y.; Liu, B.; Ma, Z.; Xia, W.; Shi, L.; Tang, Y.
Macromol Rapid Commun 2005, 26, 1609–1614.
G.; Koppl, A. Chem Rev 2000, 100, 1205–1221.
¨
2 (a) Shapiro, P. J.; Bunel, E.; Schaefer, W. P.; Bercaw, J. E. Orga-
nometallics 1990, 9, 867–869; (b) Shapiro, P. J.; Cotter, W. D.;
Schaefer, W. P.; Labinger, J. A.; Bercaw, J. E. J Am Chem Soc
1994, 116, 4623–4640; (c) Stevens, J. C.; Timmers, F. J.; Wilson,
D. R.; Schmidt, G. F.; Nickias, P. N.; Rosen, R. K.; McKnight, G.
W.; Lai, S. (Dow). Eur Patent 0416815-A2, 1991; (d) Canich, J. A.
M. (Exxon). U.S. Patent 5026798, 1991; (e) Braunschweig, H.;
Breitling, F. M. Coord Chem Rev 2006, 250, 2691–2720; (f)
Nomura, K.; Naga, N.; Miki, M.; Yanagi, K.; Imai, A. Organometal-
lics 1998, 17, 2152–2154; (g) Nomura, K.; Naga, N.; Miki, M.;
Yanagi, K. Macromolecules 1998, 31, 7588–7597; (h) Nomura, K.;
Liu, J.; Padmanabhan, S.; Kitiyanan, B. J Mol Catal A 2007, 267,
1–29; (i) Nomura, K. Dalton Trans 2009, 8811–8823.
9 (a) Paolucci, G.; Zanella, A.; Sperni, L.; Bertolasi, V.; Mazzeo,
M.; Pellecchia, C. J Mol Catal A: Chem 2006, 258, 275–283; (b)
Wang, C.; Ma, Z.; Sun, X.; Gao, Y.; Guo, Y.; Tang, Y.; Shi, L.
Organometallics 2006, 25, 3259–3266; (c) Gao, M.; Wang, C.;
Sun, X.; Qian, C.; Ma, Z.; Bu, S.; Tang, Y.; Xie, Z. Macromol
Rapid Commun 2007, 28, 1511–1516; (d) Gao, M.; Gu, Y.;
Wang, C.; Yao, X.; Sun, X.; Li, C.; Qian, C.; Liu, B.; Ma, Z.;
Tang, Y.; Xie, Z.; Bu, S.; Gao, Y. J Mol Catal A: Chem 2008,
292, 62–66; (e) Cui, K.; Liu, B.; Wang, C.; Yu, J.; Ma, Z. J Mol
Catal A: Chem 2007, 266, 93–99; (f) Fokken, S.; Reichwald, F.;
Spaniol, T.; Okuda, J. J Organomet Chem 2002, 663, 158–163.
3 (a) Zuo, W.; Zhang, S.; Liu, S.; Liu, X.; Sun, W.-H. J Polym Sci
Part A: Polym Chem 2008, 46, 3396–3410; (b) Zuo, W.; Zhang, M.;
Sun, W.-H. J Polym Sci Part A: Polym Chem 2009, 47, 357–372; (c)
Liu, S; Yi, J.; Zuo, W.; Wang, K.; Wang, D.; Sun, W.-H. J Polym Sci
Part A: Polym Chem 2009, 47, 3154–3169; (d) Sun, W.-H.; Liu, S.;
Zhang, W.; Zeng, Y.; Wang, D.; Liang, T. Organometallics 2010,
29, 732–741; (e) Liu, S.; Sun, W.-H.; Zeng, Y.; Wang, D.; Zhang,
W.; Li, Y. Organometallics 2010, 29, 2459–2464.
10 (a) Li, Z.; Sun, W.-H.; Ma, Z.; Hu, Y.; Shao, C. Chin Chem Let
2001, 12, 691–692; (b) Li, Z.; Zhu, N.; Sun, W.-H.; Shao, C.; Ke,
Y.; Hu, Y.; He, J. Polym Int 2001, 50, 1275–1278; (c) Sun, W.-H.;
Li, Z.; Hu, H.; Wu, B.; Yang, H.; Zhu, N.; Leng, X.; Wang, H.
New J Chem 2002, 26, 1474–1478; (d) Zhang, S.; Sun, W.-H.;
Xiao, T.; Hao, X. Organometallics 2010, 29, 1168–1173.
4 (a) Flores, J. C.; Chien, J. C. W.; Rausch, M. D. Organometal-
lics 1995, 14, 2106–2108; (b) Herskovicskorine, D.; Eisen, M. S.
J Organomet Chem 1995, 503, 307–314; (c) Volkis, V.; Shmulin-
son, M.; Averbuj, C.; Lisovskii, A.; Edelmann, F. T.; Eisen, M. S.
Organometallics 1998, 17, 3155–3157.
11 (a) Shen, M.; Huang, W.; Zhang, W.; Hao, X.; Sun, W.-H.;
Redshaw, C. Dalton Trans 2010, 39, 9912–9922; (b) Sun, W.-H.;
Shen, M.; Zhang, W.; Huang, W.; Liu, S.; Redshaw, C. Dalton
Trans 2011, 40; DOI:10.1039/C0DT01207F.
12 Sheldrick, G. M. SHELXTL-97, Program for the Refinement
5 (a) Clark, H. C. S.; Cloke, G. N.; Hitchcock, P. B.; Love, J. B.;
Wainwright, A. P. J Organomet Chem 1995, 501, 333–340; (b)
Scollard, J. D.; McConville, D. H. J Am Chem Soc 1996, 118,
10008–10009; (c) Scollard, J. D.; McConville, D. H.; Payne, N.
C.; Vittal, J. J. Macromolecules 1996, 29, 5241–5243; (d) Horton,
A. D.; de With, J.; van der Linden, A. J.; van de Weg, H. Orga-
nometallics 1996, 15, 2672–2674; (e) Warren, T. H.; Schrock, R.
R.; Davis, W. M. Organometallics 1998, 17, 308–321; (f) Bau-
mann, R.; Davis, W. M.; Schrock, R. R. J Am Chem Soc 1997,
119, 3830–3831; (g) Gibson, V. C.; Kimberley, B. S.; White, A. J.
P.; Williams, D. J.; Howard, P. Chem Commun 1998, 313–314.
of Crystal Structures. University of Gottingen: Germany, 1997.
¨
13 (a) Zuo, W.; Sun, W.-H.; Zhang, S.; Hao, P.; Shiga, A. J
Polym Sci Part A: Polym Chem 2007, 45, 3415–3430; (b) Liu, S.;
Zuo, W.; Zhang, S.; Hao, P.; Wang, D.; Sun, W.-H. J Polym Sci
Part A: Polym Chem 2008, 46, 3411–3423.
14 Chen, E. Y. X.; Marks, T. J. Chem Rev 2000, 100, 1391–1434.
15 (a) Mason, A. F.; Coates, G. W. J Am Chem Soc 2004, 126,
16326–16327; (b) Bochmann, M. J Chem Soc Dalton Trans
1996, 255–270.
16 Galland, G. B.; Quijada, P.; Mauler, R. S.; de Menezes, S. C.
6 (a) van der Linden, A.; Schaverien, C. J.; Meijboom, N.; Gan-
ter, C.; Orpen, A. G. J Am Chem Soc 1995, 117, 3008–3021; (b)
Fokken, S.; Spaniol, T. P.; Kang, H. C.; Massa, W.; Okuda, J.
Organometallics 1996, 15, 5069–5072.
Macromol Rapid Commun 1996, 17, 607–613.
17 Czaja, K.; Bialek, M. Polymer 2001, 42, 2289–2297.
18 Seger, M. R.; Maciel, G. E. Anal Chem 2004, 76, 5734–5747.
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