Syntheses, characterization, and the ethylene (Co-)polymerization screening of 2-benzimidazolyl-N-phenylquinoline-8-carboxamide half-titanocene chlorides

Article abstract of DOI:10.1021/om9010033

A series of 2-benzimidazolyl-/V-phenylquinoline-8-carboxamide half-titanocene chlorides, CpTiLCl (C1-C6: Cp = η⁵-C ₅H₅; L = 2-(l//-benzo[#midazol-2-yl)-N-(2,6-R ¹-4-R²-phenyl)quinoline-8-carboxamide derivatives; Cl: R¹ = i-Pr, R² = H; C2: R¹ = Et, R² = H; C3: R¹ = Me, R² = H; C4: R¹ = Me, R ² = Me; C5: R¹ = H, R² = H; C6: R¹ = F, R² = H), have been synthesized by the stoichiometric reaction of half-titanocene trichlorides with the corresponding potassium 2-benzimidazolyl-N-phenylquinoline-8-carboxamide. All complexes are fully characterized by elemental and NMR analyses, as well as single-crystal X-ray diffraction for complexes Cl, C2, and C6. In addition, the oxo-bridged dinuclear complex C7 was separated from the solution of C6 in air. These complexes, C1-C6, activated with methylaluminoxane (MAO), exhibit high catalytic activities toward both ethylene polymerization and copolymerization of ethylene with a-olefins. According to the catalytic system of Cl/MAO, both elevating the reaction temperature and increasing the ratio of MAO to titanium precursor enhance the productivities; however, the molecular weights of the resultant polymers obtained decrease against their higher activities. Moreover, copolymerizations of ethylene with either 1-hexene or 1-octene effectively produce copolymers with incorporated comonomers of 2.0-5.0% mol. 2010 American Chemical Society.

Full text of DOI:10.1021/om9010033

732 Organometallics 2010, 29, 732–741
DOI: 10.1021/om9010033
Syntheses, Characterization, and the Ethylene (Co-)Polymerization
Screening of 2-Benzimidazolyl-N-phenylquinoline-8-carboxamide
Half-Titanocene Chlorides
Wen-Hua Sun,*,†,‡ Shaofeng Liu,† Wenjuan Zhang,† Yanning Zeng,† Deligeer Wang,†,§ and
Tongling Liang†
†Key Laboratory of Engineering Plastics and Beijing Natural Laboratory for Molecular Science, Institute of
Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China, ‡State Key
Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese
Academy of Sciences, Lanzhou 730000, People’s Republic of China, and §Department of Chemistry, Inner
Mongolia Normal University, Hohhot 010022, People’s Republic of China
Received November 17, 2009
A series of 2-benzimidazolyl-N-phenylquinoline-8-carboxamide half-titanocene chlorides,
CpTiLCl (C1-C6: Cp = η5-C5H5; L = 2-(1H-benzo[d]imidazol-2-yl)-N-(2,6-R1-4-R2-phenyl)-
quinoline-8-carboxamide derivatives; C1: R1 = i-Pr, R2 = H; C2: R1 = Et, R2 = H; C3: R1 =
Me, R2 = H; C4: R1 = Me, R2 = Me; C5: R1 = H, R2 = H; C6: R1 = F, R2 = H), have been
synthesized by the stoichiometric reaction of half-titanocene trichlorides with the corresponding
potassium 2-benzimidazolyl-N-phenylquinoline-8-carboxamide. All complexes are fully character-
ized by elemental and NMR analyses, as well as single-crystal X-ray diffraction for complexes C1, C2,
and C6. In addition, the oxo-bridged dinuclear complex C7 was separated from the solution of C6 in
air. These complexes, C1-C6, activated with methylaluminoxane (MAO), exhibit high catalytic
activities toward both ethylene polymerization and copolymerization of ethylene with R-olefins.
According to the catalytic system of C1/MAO, both elevating the reaction temperature and
increasing the ratio of MAO to titanium precursor enhance the productivities; however, the
molecular weights of the resultant polymers obtained decrease against their higher activities.
Moreover, copolymerizations of ethylene with either 1-hexene or 1-octene effectively produce
copolymers with incorporated comonomers of 2.0-5.0% mol.
Introduction
to be suitable for processes of either gas phase or slurry
reactors.3 In addition to metallocenes,1,4 the “constrained
geometry” half-metallocene catalysts (namely CGC cat-
alysts) have been successfully developed and commercia-
lized;2,5 however, the modification of their expediential
ligands is restricted. Recently, the bis(phenoxyimino) or
ancillary phenoxylketimino titanium procatalysts have been
developed for living polymerization,6 while bis(imino-
pyrrolidato)titanium complexes have been explored for ole-
fin copolymerization.7 Due to the high electrophilicity of
Driven by industrial consideration for advanced polyole-
fins, significant developments have been focused on design-
ing sophisticated procatalysts toward polyolefins with
defined microstructures. A great deal of research has been
conducted on highly active (co)polymerization of olefins by
employing catalyst precursors of metallocenes1 and half-
metallocenes.2 Regarding industrial applications, it is neces-
sary to immobilize procatalysts on inorganic carriers in order
*Corresponding author. Tel: þ86-10-62557955. Fax: þ86-10-
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W. Angew. Chem., Int. Ed. 2000, 39, 3626. (d) Makio, H.; Kashiwa, N.;
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Published on Web 01/28/2010
2010 American Chemical Society

Article
Chart 1. Development of Half-Titanocene Catalysts
Organometallics, Vol. 29, No. 4, 2010 733
Scheme 1. Synthesis of Ligands L1-L6
titanium, however, these common complexes are more
sensitive than metallocenes and half-metallocenes. There-
fore, nonbridged half-metallocenes have attracted much
attention.
The nonbridged half-metallocene complexes Cp0M(L)Xn
(Cp0 = cyclopentadienyl group; M = Ti, Zr, Hf; L =
anionic ligand; X = halogen, alkyl) have shown high effi-
ciency in both catalytic activity and precisely controlling
copolymerization properties.8 To verify nonbridged half-
titanocene catalysts, the monoanionic ancillary ligands have
been used as monodentate9 or bidentate10 and the dianionic
ligand in a tridentate coordination mode.11 In addition to the
improved stability of dianionic tridentate half-titanocenes,
half-titanocene complexes bearing either N-(2-benzimidazo-
lylquinolin-8-yl)benzamidate11b or 6-benzimidazolylpyri-
dyl-2-carboximidate11c have shown high activities in
ethylene polymerization. The half-titanocene N-(2-benzimi-
dazolylquinolin-8-yl)benzamidate catalysts (A, Chart 1) per-
formed with high activities for the copolymerization of
ethylene with R-olefins,11b but the half-titanocene 6-benzi-
midazolylpyridyl-2-carboximidate catalysts did not (B,
Chart 1).11c The characteristic differences are 2-fold: verified
frameworks on the base of pyridine and quinoline, and the
different coordinative atoms of oxygen or nitrogen from the
carboximinate groups. Sequentially, the title half-titanocene
complexes bearing 2-benzimidazolyl-N-phenylquinoline-8-
carboxamide chlorides have been synthesized and investi-
gated for their catalytic behaviors. The title complexes,
activated with methylaluminoxane (MAO), show high acti-
vities in both ethylene polymerization and copolymerization
of ethylene and 1-hexene or 1-octene. Herein we report the
syntheses, characterization, and polymerization behavior of
the title complexes in detail.
2. Results and Discussions
2.1. Synthesis and Characterization of 2-(Benzimidazol-2-
yl)-N-phenylquinoline-8-carboxamide Derivatives and Their
Half-Titanocene Chlorides. There are several options of
forming carboxamide groups.12 The condensation reactions
of 2-methylquinoline-8-carboxylic acid with substituted
anilines in refluxing xylene, using trichlorophosphine
as dehydrating agent,12a,b form a series of 2-methyl-N-
phenylquinoline-8-carboxamide derivatives in high yields
(Scheme 1). Then a further reaction of 2-methyl-N-phenyl-
quinoline-8-carboxamides and o-phenylenediamine in an
excess amount of sulfur oxidant gives the corresponding
derivatives of 2-(benzimidazol-2-yl)-N-phenylquinoline-
8-carboxamides (L1-L6, Scheme 1) according to the pre-
viously reported method.13
All organic compounds are routinely characterized by
elemental, IR spectroscopic, and NMR analyses. For exam-
ple in compound L1, a strong and sharp peak at 1640 cm-1 in
its IR spectrum can be ascribed to the stretching vibration of
CdO, while the absorptions at δ 11.05 and 9.85 ppm in the its
1H NMR spectrum could be ascribed to two NH groups of
amide and benzimidazole, respectively. Similar characteris-
tics have been observed for compounds L2-L6.
(8) (a) Nomura, K. Dalton Trans. 2009, 8811. (b) Nomura, K.; Liu, J.;
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Organometallics 1998, 17, 2152. (b) Mahanthappa, M. K.; Cole, A. P.;
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Lopez, A. M.; Mateo, A. C.; Onate, E. Organometallics 2006, 25, 1448.
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tallics 1998, 17, 5228. (j) Zuo, W.; Zhang, M.; Sun, W.-H. J. Polym. Sci.,
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These 2-(benzimidazol-2-yl)-N-phenylquinoline-8-carbox-
amide derivatives could potentially act as dianionic tridentate
ligands. Thereactionof these compounds withhalf-titanocene
trichloride, however, does not produce the desired complexes.
It is necessary for these compounds to be treated with
two equivalents of KH in tetrahydrofuran (THF) to form
the potassium dianionic intermediates. The stoichiometric
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734 Organometallics, Vol. 29, No. 4, 2010
Scheme 2. Synthesis of Complexes C1-C6
Sun et al.
Figure 1. Molecular structure of complex C1. Thermal ellip-
soids are shown at the 30% probability level. Hydrogen atoms
have been omitted for clarity.
reaction of the potassium dianionic intermediates with
CpTiCl3 affords the complexes CpTiLCl (C1-C6, Cp =
C5H5; L = 2-(benzimidazol-2-yl)-N-phenylquinoline-8-car-
boxamide) (Scheme 2) in high yields. All complexes are fully
characterized by elemental and NMR spectroscopic analyses.
Comparing the NMR spectra, the peaks of L1 at δ 11.05 and
9.85 ppm (ascribed to the NH signals of amide and
benzimidazole) disappear in that of complex C1, indicating
the successful deprotonation and formation of Ti-N bonds.
Similar changes are also observed in the NMR spectra of
complexes C2-C6 and their corresponding ligands. In addi-
tion, there are two sets of resonance of CH(CH3)2 (3.51 and
2.83 ppm) for C1, which is different from only one (3.41 ppm)
for L1. It is assumed that the aryl-N bonding of complex C1
cannot freely rotate in solution because of the steric hindrance
of the ortho-isopropyl groups of the N-aryl rings. A similar
characteristic is also observed for complex C2, with four sets
of signals for -CH2CH3 and two setsof signals for -CH2CH3
(1.57 and 1.07 ppm) due to the ortho-ethyl groups of the
N-aryl rings. Other complexes (C3-C6) show no asymme-
trical signal for the ortho-methyl groups of the N-aryl rings;
therefore, the free rotation of aryl-N bonding of complexes
C3-C6 is considered in solution.
Figure 2. Molecular structure of complex C2. Thermal ellip-
soids are shown at the 30% probability level. Hydrogen atoms
have been omitted for clarity.
All complexes are highly sensitive to air and moisture. The
CH2Cl2/n-heptane solution of C6 exposed to air affords the
oxo-bridged bimetallic complex C7, which is more stable. Its
analogous complexes have also been described in our pre-
vious works.11b,c,14
Crystals of C1, C2, and C6 suitable for single-crystal X-ray
diffraction analysis have been obtained by slow diffusion of
n-heptane into their CH2Cl2 solutions. Their molecular
structures are illustrated in Figures 1, 2, and 3, respectively.
Their selected bond lengths and angles are tabulated in Table 1.
The molecular structure of C1 (Figure 1) clearly shows the
η5-binding fashion of the cyclopentadienyl group as a cap
coordinating a titanium atom; in addition, the titanium atom
is in a square-pyramidal environment with the basal posi-
tions being occupied by a chloride and three atoms (O∧N∧N)
of the tridentate dianionic 2-(benzimidazol-2-yl)-N-phenyl-
quinoline-8-carboxamide. The same coordination geometry
is also observed with other half-titanocene complexes bear-
ing dianionic ligands such as 6-benzimidazolylpyridyl-2-car-
boximidates (A, Chart 1)11b and N-benzimidazolylquinolin-8-
Figure 3. Molecular structure of complex C6. Thermal ellip-
soids are shown at the 30% probability level. Hydrogen atoms
have been omitted for clarity.
benzamides (B, Chart 1).11c Consistent with values observed in
the analogous complexes,11 the bond length of titanium and
˚
chloride (Ti1-Cl1) is 2.313(9) A, while the distance between the
centroid of the cyclopentadienyl group and titanium is 2.047 A.
˚
The bond lengths of titanium and the carbons of cyclopenta-
˚
dienyl group range from 2.349(3) to 2.395(3) A (Ti1-C24;
Ti1-C25; Ti1-C26; Ti1-C27; Ti1-C28), indicating a slight
€
€
(14) (a) Muller, J.; Kehr, G.; Frohlich, R.; Erker, G. Eur. J. Inorg.
˚
Chem. 2005, 2836. (b) Flores, J. C.; Chien, J. C. W.; Rausch, M. D.
difference (ΔTi-C = 0.046 A) caused by the different trans-
ꢀ
Macromolecules 1996, 29, 8030. (c) Esteruelas, M. A.; Lopez, A. M.;
bonding atoms in the basal plane. According to its spectra, there
is one singlet ascribed to the Cp ring in the 1H NMR (6.23 ppm,
s, 5H) and 13C NMR (121.1 ppm), suggesting its conjugated
~
Mateo, A. C.; Onate, E. Organometallics 2005, 24, 5084. (d) Gurubasavaraj,
P. M.; Roesky, H. W.; Sharma, P. M. V.; Oswald, R. B.; Dolle, V.;
Herbst-Irmer, R.; Pal, A. Organometallics 2007, 26, 3346.

Article
Organometallics, Vol. 29, No. 4, 2010 735
Table 1. Selected Bond Lengths and Angles for C1, C2, and C6
C1
Bond Lengths (A)
C2
C6
˚
Ti1-N1
Ti1-N3
Ti1-O1
Ti1-C24
Ti1-C25
Ti1-C26
Ti1-C27
Ti1-C28
Ti1-Cl1
C17-O1
C17-N4
2.082(2)
2.233(2)
1.854(2)
2.349(3)
2.365(3)
2.365(3)
2.395(3)
2.382(3)
2.313(9)
1.326(3)
1.273(3)
2.088(3)
2.257(3)
1.883(2)
2.368(3)
2.370(3)
2.353(3)
2.347(3)
2.359(3)
2.292(1)
1.330(4)
1.273(4)
2.084(2)
2.246(2)
1.898(2)
2.371(2)
2.355(3)
2.351(2)
2.374(2)
2.382(3)
2.287(9)
1.320(3)
1.283(3)
Bond Angles (deg)
N1-Ti1-N3
N1-Ti1-O1
N3-Ti1-O1
Cl1-Ti1-N1
Cl1-Ti1-N3
Cl1-Ti1-O1
74.19(8)
136.19(9)
78.92(8)
88.82(7)
140.37(6)
90.47(7)
74.08(1)
137.34(1)
77.53(1)
86.97(8)
134.87(7)
91.15(7)
74.46(8)
138.29(8)
77.93(8)
88.33(6)
137.20(6)
91.25(6)
Figure 4. Molecular structure of complex C7. Thermal ellip-
soids are shown at the 30% probability level. Hydrogen atoms
have been omitted for clarity.
characteristics in the solution state. The 2-(benzoimidazol-2-yl)-
N-(2,6-diisopropylphenyl)quinoline-8-carboxamide ligand
adopts a puckered chelating style with the dihedral angle 21.1°
defined by the two chelating rings (Ti1-N1-C7-C8-N3,
Ti1-N3-Cl6-Cl5-C17-O1), which is larger than that of
the analogous complex of model A (17.0o). The dihedral angle
between the benzimidazole and quinoline rings is 5.0°, which is
smaller than that of the corresponding analogue of model A
˚
Table 2. Selected Bond Lengths (A) and Angles (deg) for C7
Bond Lengths
Ti1-N1
Ti1-O1
Ti1-C24
Ti1-C26
Ti1-C28
C17-N4
Ti2-O3
2.096(3)
1.935(2)
2.362(4)
2.401(3)
2.334(3)
1.275(4)
1.7982(1)
Ti1-N3
Ti1-O3
Ti1-C25
Ti1-C27
C17-O1
Ti2-O2
2.270(2)
1.823(1)
2.392(3)
2.362(3)
1.320(3)
1.922(2)
(8.4°).11b The two Ti-N bond lengths (Ti1-N1 = 2.082(2) A,
Ti1-N3 = 2.233(2) A) are in the common range for titanium
complexes, but slightly different due to their different chemical
˚
˚
˚
environments. The Ti1-O1 bond length is 1.854(2) A, which is
Bond Angles
similar to the Ti-O bond in (η5-C5H5)Ti{2,20-S(OC6H2-4-Me-
6-tBu)2}Cl and (η5-C5H5)Ti(η2-MBMP)Cl,15 but shorter than
the Ti-O bond of 6-benzimidazolylpyridyl-2-carboximidate
N1-Ti1-N3
N3-Ti1-O1
N3-Ti1-O3
N5-Ti2-N7
N7-Ti2-O2
N7-Ti2-O3
Ti1-O3-Ti2
73.71(9)
77.13(9)
134.76(9)
73.36(9)
78.29(9)
134.21(9)
177.21(1)
N1-Ti1-O1
N1-Ti1-O3
O1-Ti1-O3
N5-Ti2-O2
N5-Ti2-O3
O2-Ti2-O3
137.12(1)
88.04(9)
90.79(9)
136.96(1)
85.46(9)
91.96(9)
11b
˚
half-titanocene (1.967(3) A).
The C17-O1 bond length
˚
˚
(1.326(3) A) is longer than the CdO bond (1.19-1.23 A) but
˚
shorter than the C-O single bond (1.42-1.46 A), while the
˚
C17-N4 bond (1.273(3) A) is shorter than a typical C-Nsingle
bond. These characteristics indicate the conjugated feature
within the carboximidate group.
olefin polymerization, which will be discussed in the next
section.
The complexes C2 (Figure 2) and C6 (Figure 3) possess
similar coordination features compared to C1, despite the
different substituents on the phenyl groups. Similarly, longer
C17-O1 (1.330(4) A in C2, 1.320(3) A in C6) and shorter
C17-N4 (1.273(4) A in C2, 1.283(3) in C6) bond lengths are
observed, indicating the partial delocalization within the
carboximidate group. The dihedral angles between the qui-
noline and the 2,6-substituted phenyl rings are notably
different: 57° in C1, 74.6° in C2, and 80.6° in C6. The bulky
hindrance of the ortho-substituents of the imino-aryl rings
affects the rotation of the N-aryl bond and then causes the
difference in coordination. This is consistent with the results
indicated by their NMR spectra, which show two sets of
signals of CH(CH3)2 (3.51 and 2.83 ppm) for C1 but four
sets of signals for -CH2CH3 and two sets of signals for
-CH2CH3 (1.57 and 1.07 ppm) for C2. The structural
differences also affect their catalytic behaviors during
Crystals of C7 suitable for single-crystal X-ray analysis are
obtained by layering n-heptane on a CH2Cl2 solution of
complex C6, and the mixture is exposed to air for one week.
The molecular structure is shown in Figure 4, and selected
bond lengths and angles are summarized in Table 2. The
molecular structure of C7 shows a binuclear species bridged
by an oxygen atom (O), which is similar to our previously
reported structure.11b,c The bond lengths of Ti1-O3
˚
˚
˚
˚
˚
(1.823(1) A) and Ti2-O3 (1.7982(1) A) and the angle of
Ti1-O3-Ti2 (177.2°) are common in titanium complexes.
Each titanium center is bonded to one 2-benzimidazolyl-
N-phenylquinoline-8-carboxamide ligand, one bridging
oxygen atom, and one η5-binding Cp ring. In each unit, the
coordination geometry around the titanium center can also
be described as square-pyramidal. A comparison with the
data in Table 1 shows that the structural parameters includ-
ing bond lengths and angles are similar to those of C6.
2.2. Catalytic Behavior toward Ethylene Polymerization.
According to our experience and results obtained with model
catalysts A and B (Chart 1),11b,c the title complexes (C1-C6)
were tested for ethylene polymerization in the presence of
ꢀ
~
(15) (a) Gonzalez-Maupoey, M.; Cuenca, T.; Frutos, L. M.; Castano,
O.; Herdtweck, E. Organometallics 2003, 22, 2694. (b) Amor, F.;
Fokken, S.; Kleinhenn, T.; Spaniol, T. P.; Okuda, J. J. Organomet. Chem.
2001, 621, 3.

736 Organometallics, Vol. 29, No. 4, 2010
Sun et al.
Table 3. Ethylene Polymerization with C1/MAOa
activity
(106g mol-1(Ti) h-1
c
entry
Al/Ti
T (°C)
polymer (g)
)
Tmb (°C)
Mwc (kg mol-1
)
Mw/Mn
3
3
3
1
2
3
4
5
6
7
8
10 000
20 000
25 000
30 000
35 000
30 000
30 000
30 000
30 000
30 000
30 000
80
80
80
80
80
20
60
70
100
80
80
0.191
0.271
0.411
0.488
0.479
0.198
0.436
0.446
0.470
0.270
1.26
2.29
3.25
4.93
5.86
5.75
2.38
5.23
5.35
5.64
6.48
5.04
133.6
133.5
134.8
134.0
133.0
132.2
133.0
133.5
132.5
134.2
134.0
1052
739
563
461
329
1613
595
522
415
233
588
4.9
3.0
2.4
2.3
3.9
2.4
3.7
3.6
3.5
3.4
3.0
9
10d
11e
a Conditions: 0.5 μmol of C1; 10 atm of ethylene; 10 min; toluene (total volume 100 mL). b Determined by DSC. c Determined by GPC. d Time: 5 min.
e Time: 30 min.
methylaluminoxane (MAO) as a cocatalyst. A detailed inves-
tigation of complex C1 was carried out for the optimized
reaction conditions, Al/Ti molar ratio, temperature, and
time.
Effects of Al/Ti Molar Ratio, Temperature, and Time on the
Catalytic Behavior. Regarding better performance observed by
the catalyst complex containing ortho-isopropyl groups of the
imino-aryl rings in the model catalysts A and B (Chart 1),11b,c
the catalytic system of C1/MAO was investigated in detail
by changing the reaction parameters, and the results are
summarized in Table 3. Increasing the Al/Ti molar ratio to
30 000 leads to higher activity in ethylene polymerization
(entries 1-5, Table 3). The activities increase from 2.29 ꢀ
106 g mol-1(Ti) h-1 with the Al/Ti molar ratio of 10 000 to
3
3
Figure 5. Relationship of the polymer amounts and reaction
time (entries 4, 10, and 11, Table 3).
5.86 ꢀ 106 g mol-1(Ti) h-1 with the Al/Ti molar ratio of
3
3
30 000. However, a little lower activity is obtained with
5.75 ꢀ 106 g mol-1(Ti) h-1 at the Al/Ti molar ratio of
Table 4. Ethylene Polymerization Results with C1-C6/MAOa
3
3
35 000. Such a phenomenon is common and well clarified
by the influence of Al concentration on the termination of
polymer chains.16 As the ratio of Al/Ti increases, the poly-
ethylene obtained exhibits lower Mw values (entries 1-5,
Table 3) because of increasing chain transfer with higher
MAO concentration.16,17
polymer
(g)
activity (106
Tm
(°C) (kg mol-1
Mw
Mw/
c
Mn
b
c
entry complex
g mol-1(Ti) h-1
)
)
3
3
3
1
2
3
4
5
6
C1
C2
C3
C4
C5
C6
0.488
0.460
0.446
0.484
0.356
0.326
5.86
5.52
5.35
5.81
4.27
3.91
134.0
132.8
132.8
132.6
131.6
134.3
461
432
347
382
190
235
2.3
4.7
4.6
3.7
3.5
2.5
The influence of the reaction temperature was also stu-
died. The catalytic activity is lower at 20 °C (entry 6, Table 3),
but increases with the reaction temperature elevated up to
80 °C (entries 7, 8, and 4, Table 3) and slightly decreased at
100 °C (entry 9, Table 3). This observation is consistent with
results obtained with the model catalyst A (Chart 1),11b
suggesting that the catalysts containing ligands with the
quinoline backbone play an important role in stabilizing
the active species at high temperature. This behavior is in
contrast to the traditional metallocene catalysts, possessing
lower activity at elevated temperatures,1,4 and classical FI
catalysts, showing the highest activity around 50 °C.6 The
better thermal stability of these current catalytic systems is
potentially of benefit to industrial polymerization, because
the liquefiable polymerization at high temperature favors the
viscosity of the reaction mixture with better mass transpor-
tation and temperature control.11b,c Though the molecular
weights of polyethylenes obtained decrease with elevating
reaction temperatures (entries 4, 6-9, Table 3) due to a faster
chain transfer and termination at higher temperature, their
molecular weights are high enough and comparable with
useful polyethylene.
a Conditions: 0.5 μmol of catalysts; 10 atm of ethylene; Al/Ti =
30 000; 80 °C; 10 min; toluene (total volume 100 mL). b Determined by
DSC. c Determined by GPC.
Regarding the lifetime of the C1/MAO system, the ethy-
lene polymerization is conducted over a different time per-
iod, namely, 5, 10, and 30 min (entries, 10, 4, and 11, Table 3).
Their productivities are almost linear along with reaction
time (Figure 5), and the molecular weights of the obtained
polyethylenes increase. Therefore the polymerization hap-
pens likely in a living manner, and the active species are well
maintained with a slow deactivation over a prolonged reac-
tion time.
Effect of the Ligand Environment on the Catalytic Behavior.
On the basis of the results observed with the C1/MAO
system, the title complexes were investigated with the Al/Ti
molar ratio of 30 000 at 80 °C under 10 atm of ethylene. All of
them show high activities toward ethylene polymerization
(Table 4). Compared with the model catalysts A and B
(Chart 1),11b,c the title catalysts show much better stability
at 80 °C; however, slightly lower activities are observed
according to maximum activities obtained at different condi-
tions. There are observable effects of the ligands’ environment,
(16) Koltzenburg, S. J. Mol. Catal. A: Chem. 1997, 116, 355.
(17) Chen, E. Y. X.; Marks, T. J. Chem. Rev. 2000, 100, 1391.

Article
Organometallics, Vol. 29, No. 4, 2010 737
Table 5. Copolymerization of Ethylene with 1-Hexene or 1-Octene by C1-C6/MAOa
activity
(106 g mol-1(Ti) h-1
c
entry
complex
polymer (g)
)
Tmb (°C)
Mwc (kg mol-1
)
Mw/Mn
3
3
3
1d
C1
C2
C3
C4
C5
C6
C1
C2
C3
C4
C5
C6
0.388
0.358
0.341
0.332
0.277
0.208
0.283
0.278
0.260
0.263
0.198
0.163
4.66
4.30
4.09
3.98
3.32
2.50
3.40
3.34
3.12
3.16
2.38
1.96
116.8
117.4
117.0
117.9
117.1
116.6
121.5
121.1
121.3
121.4
120.6
120.9
198
175
142
154
90.0
125
125
90.1
66.4
61.6
51.5
55.7
4.3
4.9
2.6
2.9
3.4
2.4
3.1
2.4
2.9
5.3
2.8
3.2
2d
3d
4d
5d
6d
7e
8e
9e
10e
11e
12e
a Conditions: 0.5 μmol of catalysts; 10 atm of ethylene; Al/Ti = 30 000; 80 °C; 10 min; toluene (total volume 100 mL). b Determined by DSC.
c Determined by GPC. d 5 mL of 1-hexene was added. e 5 mL of 1-octene was added.
and the activities of complexes decrease in the order C1 (R1 =
iPr) > C2 (Et) > C3 (Me) > C5 (H) > C6 (F). The activity of
C4/MAO is higher than that by the C3/MAO system, but
lower than that of C1/MAO. Indicated by the NMR and
structural differences of the complexes, steric hindrance caused
by ortho-substituents of the imino-aryl rings protects the active
species and results in high activity.17 On the other hand, the
additional methyl group of C4 increases the electron density of
the central deficient titanium. The complex C4 has a better
solubility in solution, and its active species are better stabilized,
resulting in a higher activity.17,18
The properties of the polyethylene obtained, the melting
points and molecular weights (Table 4), are characteristic of
linear and high-density polyethylene (HDPE) with Tm values
in the range 131-135 °C and their Mw values in the range 190
to 461 kg mol-1, which are much higher than those of poly-
Figure 6. 13C NMR spectrum of ethylene/1-hexene copolymer
by the C1/MAO system (entry 1, Table 5).
3
mers obtained by the model catalysts A and B (Chart 1)11b,c
and related catalytic systems.10e,f Moreover, the Mw values
of polyethylenes obtained with model catalyst A11b are 3
times higher than those of polyethylenes obtained with
model catalyst B.11c Such phenomena emphasize the impor-
tant roles of different frameworks of ligands, which cause the
different catalytic behavior of their complexes. The title
procatalysts and model catalyst A11b employ the rigid quino-
line instead of the centric pyridine ring of model catalyst B,11c
enlarging the coordination ring. Therefore, the ligands of
title procatalysts and model catalyst A11b occupy more space
around the active titanium center. It is supposed that the
chain transfer process of the half-titanocene catalyst requires
more space in the coordination sphere of the titanium than
the olefin insertion state does.19,20 So the title catalysts
produce polyethylenes with higher molecular weights than
catalysts A and B. Due to bulky substituents, the catalysts
C1 and C2 produce polyethylenes with higher molecular
weight than catalyst C5, containing ligands with less steric
influence. The active species of olefin polymerization are
generally recognized as cations, which are formed by alkyla-
tion and abstraction of halogen or ligands using alkylalumi-
num or alkylaluminoxane agents.17,18 Regarding the current
half-titanocene catalysts, there is only one Ti-Cl bond
for alkylation to form the titanium alkyl complex. The
introduction of MAO alkylated the Ti-Cl bond and opened
an additional site ligated by the ligand in order to coordinate
with the approaching monomer. According to our previous
report, the cleavage of the Ti-O bond possibly occurs during
polymerization.11c
2.3. Copolymerization of Ethylene/1-Hexene and Ethy-
lene/1-Octene. The copolymerization of ethylene with 1-
hexene and 1-octene by complexes C1-C6 was also investi-
gated. All catalysts exhibit high activities toward copoly-
merization of ethylene with 1-hexene or 1-octene, and the
results are tabulated in Table 5.
The copolymers of ethylene/1-hexene by C1-C6 have
similar Tm values. On varying the environment of the metal
center with different ligands, their catalysts perform with
similar catalytic activities in the same order as in the ethylene
polymerization, C1 (i-Pr) > C2 (Et) > C3 (Me) > C5 (H) >
C6 (F), suggesting that bulkier and donation groups are
favorable for copolymerization. The title catalysts show a
little lower activity than model catalyst A (Chart 1); however,
the Tm values (about 117 °C) of the resultant copolymers by
current catalysts are much lower than those (about 127 °C) of
copolymers by catalyst A (Chart 1). This is consistent with
the observation of the higher incorporation of 1-hexene by
the current catalytic system. The copolymers (entry 1,
Table 5), confirmed by 13C NMR in Figure 6, show the
character of linear low-density polyethylene21 and contain
(18) Bochmann, M. J. Chem. Soc., Dalton Trans. 1996, 255.
€
(19) (a) Woo, T. K.; Margl, P. M.; Lohrenz, J. C. W.; Blochl, P. E.;
Ziegler, T. J. Am. Chem. Soc. 1996, 118, 13021. (b) Woo, T. K.; Margl, P.
€
M.; Ziegler, T.; Blochl, P. E. Organometallics 1997, 16, 3454.
(20) Sinnema, P.-J.; Hessen, B.; Teuben, J. H. Macromol. Rapid
Commun. 2000, 21, 562.
(21) Simanke, A. G.; Galland, G. B.; Freitas, L.; da Jornada, J. A. H.;
Quijada, R.; Mauler, R. S. Polymer 1999, 40, 5489.

738 Organometallics, Vol. 29, No. 4, 2010
Sun et al.
Figure 7. 13C NMR spectrum of ethylene/1-octene copolymer by the C1/MAO system (entry 7, Table 5).
4.3 mol % 1-hexene incorporation. In fact, the copolymers
by catalyst A (Chart 1) contain only about 2 mol % 1-hexene
incorporation;11b therefore the current systems provide poly-
mers with higher incorporation of 1-hexene.22 The resultant
copolymers possess lower molecular weights (90-198
C1, C2, and C6 are confirmed by X-ray diffraction studies.
The complexes C1-C6, activated with excessive amounts of
MAO, exhibit high catalytic activities toward ethylene poly-
merization, especially at elevated reaction temperatures.
Bulky substituents of the imino-aryl rings are favorable for
both the catalytic activity and molecular weight (Mw) of the
resultant polymer. The title catalysts show good copolymer-
ization behavior of ethylene with 1-hexene or 1-octene,
which is superior to the model catalyst A.11b In regard to
the lack of copolymerization by model catalyst B,11c the rigid
quinoline ring within the title and model catalyst A11b plays
an important role due to the different coordination. Beyond
the improved incorporation and enhanced activity, the title
catalysts have the advantage of maintaining high activities at
elevated reaction temperature (80 °C).
kg mol-1) than the polyethylenes obtained in Table 4, but
3
still higher than those obtained by Cp*Ti(O-2,6-iPr2C6H3)-
Cl2.9e
The copolymerization of ethylene/1-octene is similar in
behavior to that of ethylene/1-hexene (Table 5), but slightly
lower activities are observed (entry n vs entry n þ 6, n = 1-6,
Table 5). The DSC analysis of the resultant copolymers by
C1-C6 shows one sole melting point around 121 °C, which is
lower than that of polyethylene obtained and higher than
that of the copolymer ethylene/1-hexene. The incorporation
of 1-octene into the copolymer is also higher than that
(1.3 mol %) of the copolymer by catalyst A (Chart 1), which
is confirmed by the 13C NMR spectrum in Figure 7 (entry 7,
Table 5), indicating a 2.4 mol % incorporation of 1-octene.
The molecular weights of poly(ethylene-1-octene) (51-125
3. Experimental Section
3.1. General Considerations. All manipulations of air- and/or
moisture-sensitive compounds were performed under a nitrogen
atmosphere or using standard Schlenk techniques. Methylalu-
minoxane (MAO, 1.46 M in toluene) was purchased from
Albemarle, and potassium hydride (KH) from Beijing Chemical
Regent Company was washed with n-hexane before use to
remove mineral oil. Tetrahydrofuran (THF), toluene, n-hexane,
and n-heptane were refluxed over sodium and benzophenone,
distilled, and then stored under a nitrogen atmosphere. Dichloro-
methane (CH2Cl2) was distilled over calcium hydride, and
stored under a nitrogen atmosphere. Highly pure ethylene was
purchased from Beijing Yansan Petrochemical Co. and used as
received. IR spectra were recorded on a Perkin-Elmer FT-IR
kg mol-1) are slightly lower than those of poly(ethylene-1-
3
hexene) obtained.
The title catalysts and model catalyst A (Chart 1)11b show
good incorporation behavior of R-olefins, and the title
catalysts are superior. The backbones of the ligand frame-
works play important roles in their incorporation behavior
and better thermal stability. Compared with the observation
that model catalyst B, bearing pyridines, was not active in
copolymerization of ethylene with R-olefins,11c the title com-
plexes and model catalyst A,11b containing the quinoline deri-
vatives, are perhaps more interesting for further investigation.
2000 spectrometer using KBr disks in the range 4000-400 cm-1
.
Elemental analysis was performed on a Flash EA 1112 micro-
1
analyzer. H NMR and 13C NMR spectra were recorded on a
Conclusions
Bruker DMX 400 MHz instrument at ambient temperature
using TMS as an internal standard. DSC traces and melting
points of polyethylenes were obtained from the second scanning
run on a Perkin-Elmer DSC-7 at a heating rate of 10 °C /min. 1H
NMR and 13C NMR spectra of the polymers were recorded on a
Bruker DMX-300 MHz instrument at 110 °C in deuterated 1,2-
dichlorobenzene with TMS as an internal standard. Molecular
weights and polydispersity indices (PDI) of (co)polyethylenes
were determined using a PL-GPC220 instrument at 135 °C in
1,2,4-trichlorobenzene with polystyrene as the standard.
The title half-titanocene complexes bearing 2-benzimid-
azolyl-N-phenylquinoline-8-carboxamide (C1-C6) have
been synthesized and characterized by 1H NMR, 13C
NMR, and elemental analyses. The molecular structures of
(22) (a) Galland, G. B.; Quijada, R.; Mauler, R. S.; de Menezes, S. C.
Macromol. Rapid Commun. 1996, 17, 607. (b) Seger, M. R.; Maciel, G. E.
Anal. Chem. 2004, 76, 5734.

Article
3.2. Synthesis and Characterization of 2-(Benzimidazol-2-yl)-
Organometallics, Vol. 29, No. 4, 2010 739
(m), 1368 (m), 1320 9 m), 1268 (m), 1208 (m), 1144 (m), 1010 (w),
857 (w), 737 (m), 683 (m). Mp: 188-189 °C. Anal. Calcd (%) for
C21H22N2O: C, 79.21; H, 6.96; N, 8.80. Found: C, 79.11; H, 6.86;
N, 9.09. 2-(1H-Benzo[d]imidazol-2-yl)-N-(2,6-diethylphenyl)-
N-phenylquinoline-8-carboxamide Derivatives (L1-L6). 2-(1H-
Benzo[d]imidazol-2-yl)-N-(2,6-diisopropylphenyl)quinoline-8-car-
boxamide (L1). First, 2,6-diisopropylbenzenamine (3.54 g, 20
mmol) was slowly added to a xylene solution (100 mL) of
2-methylquinoline-8-carboxylic acid (3.74 g, 20 mmol) at room
temperature. The mixture was stirred for 15 min and heated to
80 °C. Trichlorophosphine (0.913 g, 6.7 mmol) was added slowly
through a dropping funnel over a period of 15 min. It was then
refluxed for 6 h, and the solvent was removed by vacuum
evaporation. 2-Methyl-N-(2,6-diisopropylphenyl)quinoline-
8-carboxamide was purified by column chromatography (silica
gel, petroleum ether/ethyl acetate = 5:1) and obtained in 75.0%
yield (5.21 g, 15.0 mmol). 1H NMR (CDCl3, 400 MHz): δ 12.90
(s, N-H, 1H), 8.93 (d, J = 7.3 Hz, 1H, quin), 8.22 (d, J = 8.4 Hz,
1H, quin), 7.98 (d, J = 8.0 Hz, 1H, quin), 7.66 (t, J = 7.7 Hz, 1H,
quin), 7.40 (d, J = 8.4 Hz, 1H, quin), 7.34 (t, J = 7.6 Hz, 1H,
aryl), 7.27 (d, J = 7.6 Hz, 2H, aryl), 3.30 (sept, J = 6.8 Hz, 2H,
CH(CH3)2), 2.75 (s, 3H, CH3), 1.25 (m, 12H, CH(CH3)2). 13C
NMR (CDCl3, 100 MHz): δ 165.3, 158.8, 146.1, 145.5, 138.1,
134.5, 133.0, 132.0, 128.3, 127.8, 127.0, 126.0, 123.5, 122.0, 29.2,
25.6, 23.1. FT-IR(KBr, cm-1): 3068(w), 2962(m), 2867(w), 1647
(s), 1616 (m), 1593 (m), 1568 (m), 1524 (s), 1498 (m), 1455 (m),
1364 (m), 1325 (m), 1265 (m), 1207 (m), 1046 (m), 1008 (m), 878
(m), 836 (s), 790 (s), 743(s), 664 (m). Mp: 207 °C. Anal. Calcd (%)
for C23H26N2O: C, 79.73; H, 7.56; N, 8.09. Found: C, 79.85; H,
7.53; N, 8.07.
1
quinoline-8-carboxamide (L2): H NMR (CDCl3, 400 MHz): δ
11.34 (s, N-H, 1H, amide), 10.11 (s, N-H, 1H, imidazole), 8.77
(d, J = 7.2 Hz, 1H, quin), 8.64 (d, J = 8.6 Hz, 1H, quin), 8.46 (d,
J = 8.6 Hz, 1H, quin), 8.07 (t, J = 8.0 Hz, 1H, quin), 7.86 (d, J =
7.2 Hz, 1H, quin), 7.73 (t, J = 7.6 Hz, 1H, aryl), 7.38-7.27 (m, 4H,
aryl), 7.18 (d, J = 7.5 Hz, 2H, aryl), 2.76 (q, J = 7.5 Hz, 4H), 1.17
(t, J = 7.5 Hz, 6H). 13C NMR (CDCl3, 100 MHz): δ 165.1, 149.9,
148.7, 145.1, 144.3, 141.3, 139.0, 135.0, 134.3, 133.6, 132.3, 129.8,
129.0, 127.9, 127.4, 126.2, 124.8, 123.3, 120.6, 120.2, 111.6, 25.1,
14.4. FT-IR (KBr, cm-1): 3187 (m), 2965 (m), 1643 (s), 1602 (m),
1565 (m), 1522 (m), 1417 (m), 1372 (w), 1315 (m), 1212 (w), 915
(w), 853 (m), 744 (s), 655 (m). Mp: 220-221 °C. Anal. Calcd (%)
for C27H24N4O: C, 77.12; H, 5.75; N, 13.32. Found: C, 77.08; H,
5.68; N, 13.36.
2-(1H-Benzo[d]imidazol-2-yl)-N-(2,6-dimethylphenyl)quino-
line-8-carboxamide (L3). Using the above procedure, 2,6-di-
methylbenzenamine was used instead of 2,6-diisopropyl-
benzenamine to prepare 2-methyl-N-(2,6-dimethylphenyl)quino-
line-8-carboxamide in 74.0% yield. Then 2-methyl-N-(2,6-di-
methylphenyl)quinoline-8-carboxamide reacted with o-phenyle-
nediamine to prepare 2-(1H-benzo[d]imidazol-2-yl)-N-(2,6-
dimethylphenyl)quinoline-8-carboxamide (L3) in 50.3% yield.
2-Methyl-N-(2,6-dimethylphenyl)quinoline-8-carboxamide: 1H
NMR (CDCl3, 400 MHz): δ 13.08 (s, N-H, 1H, amide), 8.92
(d, J = 7.3 Hz, 1H, quin), 8.21 (d, J = 8.4 Hz, 1H, quin), 7.97 (d,
J = 8.0 Hz, 1H, quin), 7.66 (t, J = 7.7 Hz, 1H, quin), 7.40 (d, J =
8.4 Hz, 1H, quin), 7.19-7.13 (m, 3H, aryl), 2.79 (s, 3H, CH3), 2.40
(s, 6H, CH3). 13C NMR (CDCl3, 100 MHz): δ 164.1, 158.8, 145.4,
138.1, 135.7, 135.2, 134.3, 132.0, 128.2, 127.0, 126.6, 125.9, 123.5,
122.0, 25.6, 19.2. FT-IR (KBr, cm-1):3089(m), 2915(m), 1666(s),
1617 (m), 1595 (m), 1566 (m), 1536 (s), 1431 (m), 1374 (m), 1326
(m), 1268 (m), 1137 (m), 1036 (m), 850 (m), 805 (m), 776 (m), 689
(m), 658 (m). Mp: 124-125 °C. Anal. Calcd (%) for C19H18N2O:
C, 78.59; H, 6.25; N, 9.65. Found: C, 78.61; H, 6.26; N, 9.79.
2-(1H-Benzo[d]imidazol-2-yl)-N-(2,6-dimethylphenyl)quinoline-
The mixture of equivalent molar amounts of o-phenylenedi-
amine (1.08 g, 10 mmol) and 2-methyl-N-(2,6-diisopropylphe-
nyl)quinoline-8-carboxamide (3.46 g, 10 mmol) with excess
sulfur (1.60 g, 50 mmol) was heated to 170 °C and stirred for
12 h. On cooling to room temperature, 250 mL of THF was
added, and the precipitated solid (including unreacted sulfur)
was filtered off. The final product, 2-(1H-benzo[d]imidazol-2-
yl)-N-(2,6-diisopropylphenyl)quinoline-8-carboxamide (L1),
was purified by column chromatography (silica gel, petroleum
ether/ethyl acetate = 2:1) and obtained in 58.0% yield (2.60 g,
1
5.80 mmol). H NMR (CDCl3, 400 MHz): δ 11.05 (s, N-H,
1H, amide), 9.85 (s, N-H, 1H, imidazole), 8.83 (d, J = 7.2 Hz,
1H, quin), 8.67 (d, J = 8.5 Hz, 1H, quin), 8.48 (d, J = 8.5 Hz,
1H, quin), 8.08 (d, J = 8.0 Hz, 1H, quin), 7.87 (d, J = 5.4 Hz,
1H, aryl), 7.76 (t, J = 7.6 Hz, 1H, quin), 7.44-7.37 (m, 2H,
aryl), 7.33-7.31 (m, 4H, aryl), 3.41 (sept, J = 6.7 Hz, 2H, CH-
(CH3)2), 1.28 (d, J = 6.7 Hz, 12H, CH(CH3)2). 13C NMR
(CDCl3, 100 MHz): δ 165.8, 149.9, 148.6, 146.4, 145.1, 144.5,
139.1, 134.8, 134.1, 132.2, 132.0, 130.5, 129.1, 128.6, 127.5,
125.1, 123.9, 123.5, 120.8, 120.0, 111.5, 29.4, 24.0. FT-IR
(KBr, cm-1): 3220 (m), 2961 (s), 1640 (s), 1599 (m), 1565 (m),
1513 (m), 1416 (m), 1363 (w), 1313 (m), 1274 (m), 1213 (w), 853
(m), 740 (m), 651 (m). Mp: 238-239 °C. Anal. Calcd (%) for
C29H28N4O: C, 77.65; H, 6.29; N, 12.49. Found: C, 77.61; H,
6.36; N, 12.49.
1
8-carboxamide (L3): H NMR (CDCl3, 400 MHz): δ 11.56 (s,
N-H, 1H, amide), 10.28 (s, N-H, 1H, imidazole), 8.74 (m, 1H,
quin), 8.62 (d, J = 8.6 Hz, 1H, quin), 8.46 (d, J = 8.6 Hz, 1H,
quin), 8.06 (t, J = 8.0 Hz, 1H, quin), 7.86 (d, J = 7.1 Hz, 1H,
quin), 7.71 (t, J = 7.6 Hz, 1H, aryl), 7.38-7.26 (m, 3H, aryl),
7.14-7.06 (m, 3H, aryl), 2.33 (s, 6H, CH3). 13CNMR (CDCl3, 100
MHz): δ 164.5, 150.1, 149.1, 146.4, 145.1, 144.2, 138.5, 135.2,
135.0, 134.8, 132.2, 129.0, 128.8, 127.8, 127.2, 126.9, 124.4, 122.9,
120.5, 120.3, 111.7, 18.7. FT-IR (KBr, cm-1): 3184 (m), 2916 (w),
1643 (s), 1601 (m), 1565 (m), 1523 (m), 1473 (w), 1416 (m), 1372
(w), 1314 (m), 1272 (m), 1215 (m), 1115 (w), 899 (w), 852 (m), 768
(m), 742 (m), 655 (m). Mp: 181-182 °C. Anal. Calcd (%) for
C25H20N4O: C, 76.51; H, 5.14; N, 14.28. Found: C, 76.60; H, 4.98;
N, 14.13.
2-(1H-Benzo[d]imidazol-2-yl)-N-(2,4,6-trimethylphenyl)quino-
line-8-carboxamide (L4). Similarly, 2,4,6-trimethylbenzenamine
was used instead of 2,6-diisopropylbenzenamine to prepare 2-
methyl-N-(2,4,6-trimethylphenyl)quinoline-8-carboxamide in
82.0% yield. Then 2-methyl-N-(2,4,6-trimethylphenyl)quino-
line-8-carboxamide reacted with o-phenylenediamine to produce
2-(1H-benzo[d]imidazol-2-yl)-N-(2,4,6-trimethylphenyl)quino-
line-8-carboxamide (L4) in 60.1% yield. 2-Methyl-N-(2,4,6-tri-
methylphenyl)quinoline-8-carboxamide: 1H NMR (CDCl3, 400
MHz): δ 12.95 (s, N-H, 1H, amide), 8.91 (d, J = 7.4 Hz, 1H,
quin), 8.20 (d, J = 8.4 Hz, 1H, quin), 7.96 (d, J = 8.0 Hz, 1H,
quin), 7.65 (t, J = 7.6 Hz, 1H, quin), 7.39 (d, J = 8.4 Hz, 1H,
quin), 6.99 (s, 2H, aryl), 2.78 (s, 3H, CH3), 2.35 (s, 6H, CH3), 2.33
(s, 3H, CH3). 13C NMR (CDCl3, 100 MHz): δ 164.1, 158.6,
145.2, 137.9, 136.0, 134.8, 134.1, 133.0, 131.8, 128.8, 128.4, 126.8,
125.7, 121.9, 25.4, 21.0, 19.0. FT-IR (KBr, cm-1): 3085 (m), 2916
(m), 1665 (s), 1607 (m), 1589 (m), 1566 (m), 1546 (s), 1432 (m),
2-(1H-Benzo[d]imidazol-2-yl)-N-(2,6-diethylphenyl)quinoline-
8-carboxamide (L2). Using the above procedure, 2,6-diethyl-
benzenamine was used instead of 2,6-diisopropylbenzenamine
to prepare 2-methyl-N-(2,6-diethylphenyl)quinoline-8-carbox-
amide in 79.2% yield. Then 2-methyl-N-(2,6-diethylphe-
nyl)quinoline-8-carboxamide reacted with o-phenylenediamine
to give the 2-(1H-benzo[d]imidazol-2-yl)-N-(2,6-diethylphenyl)-
quinoline-8-carboxamide (L2) in 52.6% yield. 2-Methyl-N-(2,6-
1
diethylphenyl)quinoline-8-carboxamide: H NMR (CDCl3, 400
MHz): δ 12.96 (s, N-H, 1H, amide), 8.92 (d, J = 7.3 Hz, 1H,
quin), 8.20 (d, J = 8.4 Hz, 1H, quin), 7.96 (d, J = 8.0 Hz, 1H,
quin), 7.65 (t, J = 7.7 Hz, 1H, quin), 7.39 (d, J = 8.4 Hz, 1H,
quin), 7.26 (t, J = 7.3 Hz, 1H, aryl), 7.20 (d, J = 7.0 Hz, 2H, aryl),
2.76 (s, 3H, CH3), 2.75 (q, J = 7.5 Hz, 4H, CH2CH3), 1.23 (t, J =
7.5 Hz, 6H, CH2CH3). 13C NMR (CDCl3, 100 MHz): δ 164.9,
158.9, 145.5, 141.5, 138.2, 134.5, 134.4, 132.2, 128.2, 127.4, 126.4,
125.9, 123.8, 122.1, 25.6, 25.5, 14.9. FT-IR (KBr, cm-1): 3069 (w),
2962 (m), 2866 (m), 1665 (s), 1595 (m), 1565 (m), 1523 (s), 1459

740 Organometallics, Vol. 29, No. 4, 2010
Sun et al.
1375 (m), 1316 (m), 1137 (m), 1038 (m), 851 (m), 776 (m), 690
(m), 655 (m). Mp: 140-141 °C. Anal. Calcd (%) for C20H20N2O:
C, 78.92; H, 6.62; N, 9.20. Found: C, 78.88; H, 6.86; N, 9.10.
2-(1H-Benzo[d]imidazol-2-yl)-N-(2,4,6-trimethylphenyl)quino-
line-8-carboxamide (L4): 1H NMR (CDCl3, 400 MHz): δ 13.65
(s, N-H, 1H, amide), 11.64 (s, N-H, 1H, imidazole), 8.77 (d,
J = 8.6 Hz, 1H, quin), 8.62 (d, J = 7.3 Hz, 1H, quin), 8.53 (d,
J = 8.6 Hz, 1H, quin), 8.30 (d, J = 8.1 Hz, 1H, quin), 7.84 (t, J =
7.7 Hz, 1H, quin), 7.69 (m, 2H, aryl), 7.31-7.30 (m, 2H, aryl),
6.97 (s, 2H, aryl), 2.28 (s, 9H, CH3). 13C NMR (CDCl3, 100
MHz): δ 164.0, 150.8, 149.4, 145.0, 139.6, 138.2, 135.6, 135.3,
134.4, 132.6, 131.2, 129.0, 128.8, 127.6, 120.7, 21.1, 19.1. FT-IR
(KBr, cm-1): 3060 (m), 2916 (m), 1639 (s), 1600 (m), 1565 (m),
1529 (m), 1500 (m), 1417 (m), 1315 (m), 1273 (m), 1210 (w), 1143
(w), 1115 (m), 905 (w), 856 (m), 745 (s), 655 (m). Mp: 234-235
°C. Anal. Calcd (%) for C26H22N4O: C, 76.83; H, 5.46; N, 13.78.
Found: C, 76.88; H, 5.60; N, 13.69.
(CDCl3, 400 MHz): δ 12.25 (s, N-H, 1H, amide), 10.50 (s, N-H,
1H, imidazole), 8.90 (d, J =7.3Hz, 1H, quin), 8.68 (d, J =8.6Hz,
1H, quin), 8.50 (d, J = 8.6 Hz, 1H, quin), 8.10 (d, J = 8.1 Hz, 1H,
quin), 7.92 (d, J = 7.7 Hz, 1H, aryl), 7.78 (dd, J1 = 7.6 Hz, J2 =
7.6 Hz, 1H, quin), 7.60 (d, J = 7.7 Hz, 1H, aryl), 7.41 (dd, J1 = 7.1
Hz, J2 =8.6Hz, 1H, aryl), 7.36 (dd, J1 = 8.3Hz, J2 = 7.3 Hz, 1H,
aryl), 7.31-7.24 (m, 1H, aryl), 7.17 (d, J = 8.9 Hz, 2H, aryl). 13C
NMR (CDCl3, 100 MHz): δ 165.0, 155.5, 150.0, 148.3, 144.7,
139.2, 138.3, 134.5, 132.8, 128.9, 128.8, 127.3, 127.2, 119.9, 111.7.
FT-IR (KBr, cm-1): 3238 (m), 3049 (w), 2954 (w), 1665 (s), 1602
(m), 1566 (m), 1534 (w), 1499 (w), 1473 (m), 1415 (m), 1318 (m),
1248 (m), 1109 (w), 1038 (w), 1009 (s), 853 (m), 820 (w), 744 (m),
703 (w), 655 (m). Mp: 202-203 °C. Anal. Calcd (%) for
C23H14F2N4O: C, 69.00; H, 3.52; N, 13.99. Found: C, 69.11; H,
3.58; N, 13.90.
3.3. Synthesis of Complexes (C1-C7). (η5-Cyclopentadienyl)-
[2-(benzimidazol-2-yl)-N-(2,6-diisopropylphenyl)quinoline-8-carboxi-
midate]chlorotitanium (C1). To a THF solution (30 mL) of 2-(1H-
benzo[d]imidazol-2-yl)-N-(2,6-diisopropylphenyl)quinoline-8-
carboxamide (0.449 g, 1.00 mmol) was added KH (0.080 g, 2.00
mmol) at -78 °C. The mixture was allowed to warm to room
temperature and stirred for additional 2 h. At -78 °C, 20 mL of a
THF solution of CpTiCl3 (0.219 g, 1.00 mmol) was added dropwise
over a 30 min period. The resultant mixture was allowed to warm to
room temperature and stirred for 12 h. The residue, obtained by
removing the solvent under vacuum, was extracted with CH2Cl2
(3 ꢀ 20 mL), and the combined filtrates were concentrated under
vacuum to reduce the volume to 20 mL. n-Heptane (45 mL) was
layered, and several days later, dark red crystals were obtained
(0.396 g, 0.665 mmol, yield 66.5%). 1H NMR (CDCl3, 400 MHz): δ
9.21 (d, J = 7.4 Hz, 1H, quin), 8.55 (s, 2H, quin), 8.10 (d, J = 7.9
Hz, 1H, quin), 7.96 (d, J = 8.0 Hz, 1H, quin), 7.82 (d, J = 7.2 Hz,
1H, aryl), 7.80 (d, J = 7.5 Hz, 1H, aryl), 7.33 (d, J = 7.4 Hz, 1H,
aryl), 7.29-7.26 (m, 1H, aryl), 7.19-7.12 (m, 3H, aryl), 6.23 (s, 5H,
Cp), 3.51 (m, 1H, CH(CH3)2), 2.83 (m, 1H, CH(CH3)2), 1.42 (m,
6H, CH(CH3)2), 1.23 (m, 3H, CH(CH3)2), 0.99 (m, 3H, CH-
(CH3)2). 13C NMR (CDCl3, 100 MHz): δ 154.3, 143.0, 142.8,
137.8, 137.3, 136.0, 132.3, 129.9, 129.2, 128.4, 128.3, 127.7, 125.4,
125.2, 123.7, 123.2, 122.5, 121.1, 120.0, 119.5, 118.9, 118.7, 32.0, 29.8,
23.1, 22.8, 21.5, 14.3. Anal. Calcd (%) for C34H31ClN4OTi: C, 68.64;
H, 5.25; N, 9.42. Found: C, 68.63; H, 5.28; N, 9.43.
2-(1H-Benzo[d]imidazol-2-yl)-N-phenylquinoline-8-carboxamide
(L5). Similarly, aniline was used instead of 2,6-diisopropylbenzen-
amine to prepare 2-methyl-N-phenylquinoline-8-carboxamide in
71.0% yield. Then 2-methyl-N-phenylquinoline-8-carboxamide
reacts with o-phenylenediamine to prepare 2-(1H-benzo[d]-
imidazol-2-yl)-N-phenylquinoline-8-carboxamide (L5) in 60.1%
yield. 2-Methyl-N-phenylquinoline-8-carboxamide: 1H NMR
(CDCl3, 400 MHz): δ 14.05 (s, N-H, 1H, amide), 8.92 (d, J =
7.4 Hz, 1H, quin), 8.20 (d, J = 8.4 Hz, 1H, quin), 7.95 (d, J = 8.0
Hz, 1H, quin), 7.89 (m, 2H, aryl and quin), 7.66 (t, J = 7.6 Hz, 1H,
quin), 7.42 (m, 3H, aryl), 7.15 (t, J = 8.0 Hz, 1H, aryl), 2.90 (s, 3H,
CH3). 13C NMR (CDCl3, 100 MHz): δ 164.5, 158.4, 144.2, 139.5,
138.0, 133.9, 132.1, 129.1, 127.7, 126.8,125.8, 123.8, 121.9, 120.2,
25.4. FT-IR (KBr, cm-1): 3064 (w), 2921 (m), 1670 (s), 1619 (m),
1594 (m), 1558 (s), 1499 (m), 1489 (m), 1444 (m), 1374 (m), 1330
(m), 1308 (m), 1267 (m), 1237 (w), 1137 (m), 1030 (w), 910 (m), 874
(m), 779 (m), 751 (s), 688 (m), 664 (m). Mp: 109-110 °C. Anal.
Calcd (%) for C17H14N2O: C, 77.84; H, 5.38; N, 10.68. Found: C,
77.82; H, 5.60; N, 10.69. 2-(1H-Benzo[d]imidazol-2-yl)-N-phenyl-
1
quinoline-8-carboxamide (L5): H NMR (CDCl3, 400 MHz): δ
13.62 (s, N-H, 1H, amide), 13.44 (s, N-H, 1H, imidazole), 8.80
(d, J = 8.5 Hz, 1H, quin), 8.72 (d, J = 7.3 Hz, 1H, quin), 8.49 (d,
J = 8.5 Hz, 1H, quin), 8.31-8.29 (m, 3H, ph and quin), 7.85 (t,
J = 7.6 Hz, 1H, quin), 7.82-7.70 (m, 2H, aryl), 7.46 (t, J = 7.4 Hz,
2H, aryl), 7.36-7.34 (m, 2H, aryl), 7.15 (t, J = 7.2 Hz, 1H, aryl).
13C NMR (CDCl3, 100 MHz): δ 163.5, 161.1, 158.3, 153.0, 150.3,
148.2, 144.7, 139.9, 138.1, 134.2, 132.9, 129.7, 129.2, 128.6, 127.7,
124.0, 120.0, 111.5. FT-IR (KBr, cm-1): 3088 (m), 2910 (m), 1654
(s), 1618 (m), 1568 (m), 1531 (m), 1501 (m), 1418 (m), 1310 (m),
1270 (m), 1215 (w), 1145 (w), 1112 (m), 895 (w), 856 (m), 747 (s),
651 (m). Mp: 166 °C. Anal. Calcd (%) for C23H16N4O: C, 75.81; H,
4.43; N, 15.38. Found: C, 75.85; H, 4.48; N, 15.66.
2-(1H-Bbenzo[d]imidazol-2-yl)-N-(2,6-difluorophenyl)quinoline-
8-carboxamide (L6). Similarly, 2,6-difluorobenzenamine was
used instead of 2,6-diisopropylbenzenamine to prepare 2-methyl-
N-difluorophenylquinoline-8-carboxamide in 72.0% yield. 2-
Methyl-N-difluorophenylquinoline-8-carboxamide reacted with
o-phenylenediamine to give 2-(1H-benzo[d]imidazol-2-yl)-N-phenyl-
quinoline-8-carboxamide (L6) in 46.0% yield. 2-Methyl-N-di-
fluorophenylquinoline-8-carboxamide: 1H NMR (CDCl3, 400
MHz): δ 13.63 (s, N-H, 1H, amide), 8.87 (d, J = 7.3 Hz, 1H,
quin), 8.17 (d, J = 8.4 Hz, 1H, quin), 7.95 (d, J = 8.0 Hz, 1H,
quin), 7.63 (t, J = 7.6 Hz, 1H, quin), 7.37 (d, J = 8.4 Hz, 1H,
quin), 7.20 (m, 1H, aryl), 7.03 (d, J = 8.0 Hz, 1H, aryl), 7.01 (d,
J = 8.0 Hz, 1H, aryl), 2.80 (s, 3H, CH3). 13C NMR (CDCl3, 100
MHz): δ 164.3, 159.1, 158.9, 156.6, 144.9, 138.0, 134.3, 132.5,
127.4, 126.8, 126.5, 125.8, 122.1, 111.9, 25.4. FT-IR (KBr, cm-1):
3080 (w), 2915 (m), 1671 (s), 1617 (m), 1599 (m), 1568 (m), 1516
(s), 1435 (m), 1375 (m), 1321 (m), 1268 (m), 1138 (m), 1037 (m),
851 (m), 808 (m), 776 (m), 687 (m), 651 (m). Mp: 131-132 °C.
Anal. Calcd (%) for C17H12F2N2O: C, 68.45; H, 4.05; N, 9.39.
Found: C, 68.29; H, 4.06; N, 9.69. 2-(1H-Benzo[d]imidazol-2-yl)-
N-(2,6-difluorophenyl)quinoline-8-carboxamide (L6): 1H NMR
η5-Cyclopentadienyl[2-(benzimidazol-2-yl)-N-(2,6-diethylphe-
nyl)quinoline-8-carboximidate] chlorotitanium (C2). Using the
same procedure for the synthesis of C1, C2 was obtained as a
dark red solid in 60.5% yield. 1H NMR (CDCl3, 400 MHz): δ
9.36 (d, J = 6.0 Hz, 1H, quin), 8.43 (d, J = 6.9 Hz, 1H, quin),
8.14 (d, J = 7.5 Hz, 1H, quin), 8.08 (d, J = 6.0 Hz, 1H, quin),
7.81 (m, 1H, aryl), 7.38-7.36 (m, 3H, aryl), 6.96 (t, J = 7.0 Hz,
1H, quin), 6.89 (d, J = 7.2 Hz, 1H, aryl), 6.71 (m, 1H, aryl), 6.04
(m, 1H, aryl), 5.86 (s, 5H, Cp), 3.27-3.17 (m, 1H, CH(CH3)2),
2.96-2.90 (m, 1H, CH(CH3)2), 2.68-2.60 (m,1H, CH(CH3)2),
2.49-2.45 (m, 1H, CH(CH3)2), 1.57 (t, J = 7.3 Hz, 3H, CH-
(CH3)2), 1.07 (t, J = 7.2 Hz, 3H, CH(CH3)2). 13C NMR (CDCl3,
100 MHz): δ 165.0, 150.8, 149.4, 144.4, 141.6, 139.5, 135.7,
135.4, 132.6, 132.0, 131.7, 129.4, 128.7, 127.5, 127.2, 126.1,
125.8, 124.3, 122.8, 120.7, 120.1, 112.7, 24.9, 14.6. Anal. Calcd
(%) for C32H27ClN4OTi: C, 67.80; H, 4.80; N, 9.88. Found: C,
67.73; H, 4.80; N, 9.82.
η5-Cyclopentadienyl[2-(benzimidazol-2-yl)-N-(2,6-dimethyl-
phenyl)quinoline-8-carboximidate]chlorotitanium (C3). Using
the same procedure for the synthesis of C1, C3 was obtained
as a dark red solid in 58.0% yield. 1H NMR (CDCl3, 400 MHz):
δ 9.22 (d, J = 6.9 Hz, 1H, quin), 8.54 (s, 2H, quin), 8.09 (d, J =
7.4 Hz, 1H, quin), 7.95 (d, J = 7.7 Hz, 1H, aryl), 7.82-7.80 (m,
1H, aryl), 7.34 (t, J = 7.1 Hz, 1H, quin), 7.30-7.26 (m, 1H,
aryl), 7.14 (d, J = 7.3 Hz, 2H, aryl), 7.04 (d, J = 7.0 Hz, 2H,
aryl), 6.22 (s, 5H, Cp), 2.39 (s, 6H, CH3). 13C NMR (CDCl3, 100
MHz): δ 155.4, 146.7, 145.0, 144.8, 143.2, 142.7, 138.0, 137.2,
135.5, 132.5, 129.9, 129.2, 128.4, 128.0, 127.6, 125.5, 125.2,
123.7, 121.2, 119.9, 118.9, 118.6, 19.0. Anal. Calcd (%) for

Article
Organometallics, Vol. 29, No. 4, 2010 741
C30H23ClN4OTi: C, 66.87; H, 4.30; N, 10.40. Found: C, 66.73;
H, 4.21; N, 10.50.
100 MHz): δ 162.8, 157.4, 157.3, 155.1, 154.1, 146.1, 143.9,
141.7, 136.7, 132.9, 129.1, 128.3, 128.1, 127.1, 122.7, 122.4,
119.5, 118.9, 115.7, 112.1, 111.7. Anal. Calcd (%) for C56H34-
F4N8O3Ti2: C, 64.76; H, 3.30; N, 10.79. Found: C, 64.70; H,
3.39; N, 10.82.
η5-Cyclopentadienyl[2-(benzimidazol-2-yl)-N-(2,4,6-trimethylphe-
nyl)quinoline-8-carboximidate]chlorotitanium (C4). Using the same
procedure for the synthesis of C1, C4 was obtained as a dark red
solid in 68.5%. 1H NMR (CDCl3, 400 MHz): δ 9.20 (d, J = 7.3 Hz,
1H, quin), 8.53 (s, 2H, quin), 8.06 (d, J = 7.8 Hz, 1H, quin), 7.95 (d,
J = 7.9 Hz, 1H, aryl), 7.82-7.76 (m, 2H, aryl), 7.34 (t, J = 7.4 Hz,
1H, quin), 7.30-7.26 (m, 1H, aryl), 6.95 (s, 2H, aryl), 6.22 (s, 5H,
Cp), 2.36 (s, 3H, CH3), 2.29 (s, 6H, CH3). 13C NMR (CDCl3, 100
MHz): δ 155.3, 145.2, 143.0, 142.7, 142.1, 135.6, 132.7, 132.2, 129.8,
129.5, 129.1, 128.5, 128.3, 128.1, 127.4, 125.3, 125.1, 123.4, 121.1,
119.9, 118.7, 118.4, 21.0, 18.9. Anal. Calcd (%) for C31H25ClN4OTi:
C, 67.34; H, 4.56; N, 10.13. Found: C, 67.36; H, 4.39; N, 10.16.
η5-Cyclopentadienyl[2-(benzimidazol-2-yl)-N-phenylquinoline-8-
carboximidate]chlorotitanium (C5). Using the same procedure for
the synthesis of C1, C5 was obtained as a dark red solid in 50.0%
3.4. Procedures for Ethylene Polymerization and Copolymer-
ization of Ethylene with r-Olefin. A 250 mL autoclave stainless
steel reactor equipped with a mechanical stirrer and a tempera-
ture controller was heated under vacuum for at least 2 h at 80 °C.
It was allowed to cool to the required reaction temperature
under an ethylene atmosphere and then charged with toluene
(with monomer), the desired amount of cocatalyst, and a
toluene solution of the catalytic precursor. The total volume
was 100 mL. After reaching the reaction temperature, the
reactor was sealed and pressurized to 10 atm of ethylene
pressure. The ethylene pressure iwas kept constant during the
reaction time by feeding the reactor with ethylene. After a period
of desired reaction time, the polymerization reaction was
quenched by addition of acidic ethanol. The precipitated poly-
mer was washed with ethanol several times and dried at 60 °C
under vacuum overnight.
1
yield. H NMR (CDCl3, 400 MHz): δ 9.16 (d, J = 6.8 Hz, 1H,
quin), 8.54 (s, 2H, quin), 8.07 (d, J = 7.6 Hz, 1H, quin), 8.02 (d,
J = 8.1 Hz, 1H, aryl), 7.84 (d, J = 8.1 Hz, 1H, aryl), 7.78 (t, J =
7.5 Hz, 1H, quin), 7.65 (d, J = 7.7 Hz, 2H, aryl), 7.47 (t, J = 7.5
Hz, 2H, aryl), 7.38 (t, J = 7.4 Hz, 1H, aryl), 7.31-7.29 (m, 1H,
aryl), 7.17 (d, J = 7.0 Hz, 1H, aryl), 6.27 (s, 5H, Cp). 13C NMR
(CDCl3, 100 MHz): δ 157.1, 150.5, 149.0, 145.6, 144.5, 141.4,
139.2, 136.1, 134.9, 133.4, 132.1, 129.9, 128.9, 128.1, 127.3, 126.1,
124.5, 121.0, 120.3, 119.8, 117.6, 111.5. Anal. Calcd (%) for
C28H19ClN4OTi: C, 65.84; H, 3.75; N, 10.97. Found: C, 65.84;
H, 3.71; N, 10.96.
3.5. X-ray Structure Determination. Crystals of C1, C2, and
C6 suitable for single-crystal X-ray analysis were obtained by
laying heptane on their CH2Cl2 solutions. Crystals of C7
suitable for single-crystal X-ray analysis were obtained by
slowly laying heptane on a CH2Cl2 solution of complex C6
and then opening this solution to air for one week. Single-crystal
X-ray diffraction for C1, C2, C6, and C7 were performed on a
Rigaku RAXIS Rapid IP diffractometer with graphite-mono-
η5-Cyclopentadienyl[2-(benzimidazol-2-yl)-N-(2,6-difluorophe-
nyl)quinoline-8-carboximidate]chlorotitanium (C6). Using the
same procedure for the synthesis of C1, C6 was obtained as a
˚
chromated Mo KR radiation (λ = 0.71073 A) at 173(2) K. Cell
parameters were obtained by global refinement of the positions
of all collected reflections. Intensities were corrected for Lorentz
and polarization effects and numerical absorption. The struc-
tures were solved by direct methods and refined by full-matrix
least-squares on F2. All non-hydrogen atoms were refined
anisotropically. Structure solution and refinement were per-
formed by using the SHELXL-97 package.23 Crystal data
collection and refinement details for all compounds are avail-
able in the Supporting Information.
1
dark red solid in 62.0% yield. H NMR (CDCl3, 400 MHz): δ
9.16 (d, J = 7.4 Hz, 1H, quin), 8.54 (s, 2H, quin), 8.10 (d, J = 7.8
Hz, 1H, quin), 7.93 (d, J = 8.0 Hz, 1H, aryl), 7.81 (d, J = 7.8 Hz,
1H, aryl), 7.77 (t, J = 7.7 Hz, 1H, quin), 7.35 (t, J = 7.5 Hz, 1H,
aryl), 7.29 (t, J = 7.6 Hz, 1H, aryl), 7.13-7.09 (m, 1H, aryl), 7.04
(d, J = 7.6 Hz, 1H, aryl), 7.02 (d, J = 7.6 Hz, 1H, aryl), 6.32 (s,
5H, Cp). 13C NMR (CDCl3, 100 MHz): δ 159.5, 157.0, 150.2,
149.5, 144.8, 144.5, 139.6, 135.8, 134.8, 133.4, 132.4, 129.2, 128.9,
128.4, 127.5, 127.2, 124.2, 120.7, 120.2, 119.6, 117.2, 111.8. Anal.
Calcd (%) for C28H17ClF2N4OTi: C, 61.51; H, 3.13; N, 10.25.
Found: C, 61.50; H, 3.11; N, 9.98.
Acknowledgment. This work is supported by NSFC
Nos. 20874105 and 20904059. We are grateful to Prof.
Manfred Bochmann and Dr. Mark Schormann for their
kindness in proofreading the manuscript.
Bis{η5-cyclopentadienyl[2-(benzimidazol-2-yl)-N-(2,6-difluoro-
phenyl)quinoline-8-carboximidate]titanium}(μ-oxo) (C7). Ac-
cording to our previous report,11b,c dimetallic complex C7 was
prepared by slowly diffusing n-heptane into a dichloromethane
solution of C6 in the air. Red crystals were obtained one week
later in 45.0% yield. 1H NMR (CDCl3, 400 MHz): δ 9.33 (d, J =
7.1 Hz, 2H, quin), 8.42 (d, J = 8.0 Hz, 2H, quin), 8.11 (d, J = 7.9
Hz, 4H, quin), 7.81 (dd, J1 = 7.6 Hz, J2 = 8.0 Hz, 2H, quin),
7.38 (d, J = 8.0 Hz, 2H, aryl), 7.31 (d, J = 7.3 Hz, 2H, aryl),
7.17-7.16 (m, 2H, aryl), 7.12-7.10 (m, 4H, aryl), 6.68 (m, 2H,
aryl), 6.09 (s, 10H, Cp), 5.88 (m, 2H, aryl). 13C NMR (CDCl3,
Supporting Information Available: The GPC diagrams of
corresponding polyolefins, crystal data and processing para-
meters for complexes C1, C2, C6, and C7, and a CIF file giving
X-ray crystal structural data. This material is available free of
charge via the Internet at http://pubs.acs.org.
(23) Sheldrick, G. M. SHELXTL-97, Program for the Refinement of
€
€
Crystal Structures; University of Gottingen: Gottingen (Germany), 1997.