2-Benzoimidazol-8-alkylquinolinylnickel(II) complexes as efficient catalysts for ethylene oligomerization and vinyl polymerization of norbornene

Article abstract of DOI:10.1080/00958972.2015.1082555

A series of nickel complexes LNiCl2 (C1-C16), where L represents 2-benzoimidazol-8-alkylquinoline and its derivatives, were prepared as potential catalysts for the oligomerization of ethylene. The molecular structure of a representative complex C2·CH3CH2OH was determined by single-crystal X-ray diffraction. Upon treatment with diethylaluminium chloride (Et2AlCl), all nickel complex pre-catalysts exhibited good activities in the oligomerization of ethylene. Furthermore, in the presence of methylaluminoxane (MAO), the nickel pre-catalysts were suitable for vinyl polymerization of norbornene.

Full text of DOI:10.1080/00958972.2015.1082555

Journal of Coordination Chemistry
ISSN: 0095-8972 (Print) 1029-0389 (Online) Journal homepage: http://www.tandfonline.com/loi/gcoo20
2-Benzoimidazol-8-alkylquinolinylnickel(II)
complexes as efficient catalysts for ethylene
oligomerization and vinyl polymerization of
norbornene
Xinfang Wei, Yunqing Jiang, Xue Cui, Yue Li, Haiwang Wang & Xiwei Qi
To cite this article: Xinfang Wei, Yunqing Jiang, Xue Cui, Yue Li, Haiwang Wang & Xiwei Qi
(
2015) 2-Benzoimidazol-8-alkylquinolinylnickel(II) complexes as efficient catalysts for ethylene
oligomerization and vinyl polymerization of norbornene, Journal of Coordination Chemistry,
8:21, 3825-3838, DOI: 10.1080/00958972.2015.1082555
6
To link to this article: http://dx.doi.org/10.1080/00958972.2015.1082555
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Date: 09 October 2015, At: 06:00

Journal of Coordination Chemistry, 2015
Vol. 68, No. 21, 3825–3838, http://dx.doi.org/10.1080/00958972.2015.1082555
2
-Benzoimidazol-8-alkylquinolinylnickel(II) complexes as
efficient catalysts for ethylene oligomerization and vinyl
polymerization of norbornene
XINFANG WEI*†§, YUNQING JIANG§, XUE CUI§, YUE LI§, HAIWANG WANG†‡§
and XIWEI QI*†§
†School of Materials and Metallurgy, Northeastern University, Shenyang, PR China
‡State Key Laboratory of Metastable Materials Science and Technology, Yanshan University,
Qinhuangdao, PR China
§Hebei Provincal Laboratory for Dielectric and Electrolyte Materials, Northeastern University at
Qinhuangdao, Qinhuangdao, PR China
(
Received 24 March 2015; accepted 30 July 2015)
N
NR2
R1
N
Ni
Cl
Cl
A series of nickel complexes LNiCl
line and its derivatives, were prepared as potential catalysts for the oligomerization of ethylene. The
molecular structure of a representative complex C2·CH CH OH was determined by single-crystal
X-ray diffraction. Upon treatment with diethylaluminium chloride (Et AlCl), all nickel complex
2
(C1–C16), where L represents 2-benzoimidazol-8-alkylquino-
3
2
2
pre-catalysts exhibited good activities in the oligomerization of ethylene. Furthermore, in the
presence of methylaluminoxane (MAO), the nickel pre-catalysts were suitable for vinyl polymeriza-
tion of norbornene.
Keywords: Nickel complex; 2-Benzoimidazol-8-alkylquinoline; Ethylene oligomerization;
Norbornene polymerization
1. Introduction
With the increasing demand for α-olefins in synthetic lubricants, plasticizers, and surfactants
1], catalysts for the oligomerization of ethylene have gained significant attention in
[
*
Corresponding authors. Email: 63525354@qq.com (X. Wei); qxw@mail.neuq.edu.cn (X. Qi)
2015 Taylor & Francis
©

3
826
X. Wei et al.
academia and industry [2]. The emergence of the Shell Higher Olefin Process [1,3,4] and
highly active pre-catalysts, and the commercialization of dimine-type nickel dichloride com-
plexes [5] revived the research on nickel systems for ethylene polymerization. Accordingly,
various nickel complexes have been explored and different ligand sets have been employed,
N^N [6–19], N^O [20–25], N^P [26–29], P^O [30,31], P^P [32,33], or tridentate ligands
such as N^N^N [34–41], N^N^O [42,43], N^N^P [44,45], and N^P^N [46,47]. In addition,
nickel complex pre-catalysts have shown considerable activity in vinyl polymerization of
norbornene [48–57] to produce soluble polynorbornenes. N,N-bidentate Ni(II) complexes
have attracted particular attention. Recently, substituted 8-(benzoimidazol-2-yl) quinoline
derivatives were employed, and the resulting systems were found to have high activity in
the polymerization of ethylene at 100 °C [58,59].
To develop new nickel complex pre-catalysts with high activities, in this study
2
-benzoimidazol-8-alkylquinoline derivatives were synthesized and reacted with NiCl to
2
obtain nickel complexes. Upon activation with ethylaluminium sesquichloride (Et Al Cl ,
3
2
3
EASC), these nickel complexes exhibited higher activities in the dimerization of ethylene.
Moreover, they showed suitable activities in vinyl polymerization of norbornene in the
presence of methylaluminoxane (MAO). The catalytic performance of the pre-catalysts in
the oligomerization of ethylene and vinyl polymerization of norbornene was investigated.
2
2
. Results and discussion
.1. Synthesis and characterization of complexes
A series of 2-(benzoimidazol-8-yl)quinolines (L1–L16) were prepared according to
1
13
scheme 1. All ligands were characterized by FT-IR, H, and C NMR spectroscopic
measurements, in addition to elemental analysis. Reaction of 2-(benzoimidazol-8-yl)
quinolines with an equivalent nickel halide [NiCl ·6H O] in CH Cl afforded the title
2
2
2
2
nickel complexes (scheme 1: C1–C16) in high yields. All nickel complexes were charac-
terized by FT-IR and elemental analysis, and were highly stable in the solid state and in
solution.
In comparison with the FT-IR spectra of the free organic compounds, the absorption
bands of the complexes shifted to lower frequencies, suggesting coordination effects. The
molecular structure of C2 was confirmed by single-crystal X-ray diffraction studies.
2
.2. Structural features
Single crystals of C2·CH CH OH, suitable for X-ray diffraction, were obtained by slow
3
2
diffusion of diethyl ether into ethanol and DMF solutions. The molecular structure is shown
in figure 1, and selected bond lengths and angles are shown in table 1.
In C2·CH CH OH, the geometry around nickel can be described as distorted trigonal
3
2
bipyramidal, in which the nickel is surrounded by one bidentate ligand, two chlorides, and
one CH CH OH coordinated via oxygen. The axial positions are occupied by N1 of the
3
2
chelate and O1 of CH CH OH (O(1)–Ni(1)–N(1) 172.72(12)°), while the equatorial plane
3
2
is formed by N2 and two chlorides. The Ni1–N2 bond (2.007(3) Å) is significantly shorter
than the Ni1–N1 bond (2.103(3) Å), owing to the coordination of the CH CH OH
3
2
molecule. Notably, the quinoline ring and benzoimidazole are not coplanar, as they have a
dihedral angle of 84.85°.

Nickel(II) complexes for ethylene oligomerization
3827
3 2
Figure 1. Molecular structure of C2·CH CH OH with thermal ellipsoids at the 30% probability level. Hydrogens
have been omitted for clarity.
NH2
NH2
NO2
N
N
CHO
NH
R1
R1
2
R
S8
o
Na S O
DMF/H2O
170 C
2
2
4
(
3 : 1)
N
N
NR2
NH
R1
R1
N
N
N
R2 = Me, Et, i-Pr
iC
l
2
6
C
H
2
H
2
C
l
O
2
N
NR2
R1
N
Ni
Cl
C1 - C16
Cl
L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 L13 L14 L15 L16
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16
R1
R2
H
H
H
H
Me Me Me Me Et Et Et Et
iPr iPr iPr iPr
Me Et
H
Me Et
iPr H
Me Et
iPr H
Me Et
iPr
H
iPr
Scheme 1. Synthetic procedure.

3
828
X. Wei et al.
3 2
Table 1. Selected bond lengths (Å) and angles (°) for C2·CH CH OH.
Bond lengths (Å)
Bond angles (°)
Ni(1)–N(1)
2.103(3)
2.007(3)
2.070(3)
2.2945(14)
2.3126(13)
1.342(5)
1.369(5)
1.317(5)
1.392(5)
1.251(5)
N(2)–Ni(1)–O(1)
93.91(13)
78.81(13)
172.72(12)
112.79(11)
91.13(10)
91.61(10)
109.53(11)
92.15(10)
90.42(10)
137.19(5)
Ni(1)–N(2)
Ni(1)–O(1)
Ni(1)–Cl(1)
Ni(1)–Cl(2)
N(1)–C(9)
N(1)–C(1)
N(2)–C(10)
N(2)–C(16)
O(1)–C(101)
N(2)–Ni(1)–N(1)
O(1)–Ni(1)–N(1)
N(2)–Ni(1)–Cl(1)
O(1)–Ni(1)–Cl(1)
N(1)–Ni(1)–Cl(1)
N(2)–Ni(1)–Cl(2)
O(1)–Ni(1)–Cl(2)
N(1)–Ni(1)–Br(2)
Cl(1)–Ni(1)–Cl(2)
2
2
.3. Ethylene oligomerization
.3.1. Effects of co-catalyst on catalytic behavior. Different co-catalysts, such as
methylaluminoxane (MAO), modified methylaluminoxane (MMAO), diethylaluminium
chloride (Et AlCl), and ethylaluminium sesquichloride (Et Al Cl , EASC), were selected as
2
3
2
3
activators of the nickel complexes in the oligomerization of ethylene. The results are pre-
sented in table 2. Higher activities were obtained with Et AlCl, and the selectivity for C
2
4
-1
6
−1
was more than 90%. Notably, C6 showed activities of up to 3.12 × 10 g mol (Ni) h
upon activation with Et AlCl. Therefore, Et AlCl was selected for further investigation. In
2
2
order to determine the optimum results, detailed investigations of C6 were conducted under
various conditions including different molar ratios of the co-catalysts to nickel complex and
reaction temperatures under 10 atm of ethylene (table 2).
2
.3.2. Effects of reaction parameters on catalytic behavior. As shown in table 3, the
reaction parameters had an influence on the catalytic activity in the oligomerization of ethy-
lene. In the C6/Et AlCl system, the molar ratio of Et AlCl to the nickel pro-catalyst (Al/Ni)
2
2
greatly affected the catalytic activity (entries 4–9, table 2). The optimum Al/Ni molar ratio
a
Table 2. Ethylene oligomerization with pre-catalyst C6.
c
Oligomer distribution (%)
b
Entry
Co-Cat.
T (°C)
Al/Ni
Activity
α–C
4
C4
C6
1
2
3
4
5
6
7
8
9
MAO
MMAO
EASC
30
30
30
30
30
30
30
30
30
40
50
1000
1000
200
200
100
250
300
400
500
250
250
0.23
0.13
1.61
2.91
1.45
3.12
2.89
2.47
2.08
2.10
1.18
88.0
84.0
80.1
79.3
84.2
78.2
77.6
78.8
77.7
76.5
75.5
94.0
94.1
93.7
93.2
93.5
93.9
93.1
93.5
93.4
93.5
93.8
6.0
5.9
6.3
6.8
6.5
6.1
6.9
6.5
6.6
6.5
6.2
Et
2
Et
2
Et
2
Et
2
Et
2
Et
2
Et
2
Et
2
AlCl
AlCl
AlCl
AlCl
AlCl
AlCl
AlCl
AlCl
1
11
0
a
2 4
Conditions: 5 μmol Ni, 10 atm C H , 20 min, 100 mL of toluene.
b
c
–1
–1
Activity, mol (Ni) h
.
Determined by GC, ∑C denotes the total amount of oligomers.

Nickel(II) complexes for ethylene oligomerization
3829
at 30 °C was 250 : 1. The selectivity toward α-olefins and distribution of oligomers varied
only slightly. Upon changing the Al/Ni molar ratio, the selectivity toward α-olefins and the
distribution of oligomers varied only slightly. However, increasing the reaction temperature
resulted in a considerable reduction in catalytic activity (entries 6, 10, and 11 in table 2),
potentially because of instability of the active species, or a lower concentration of ethylene
in the reaction solution [27,39]. Upon increasing the temperature to 50 °C, much lower
activity was observed, in addition to a lower selectivity toward α-olefins. Catalytic activity
6
−1 −1
of 3.12 × 10 g mol
h
was observed under the optimized reaction conditions of an
Et AlCl/Ni molar ratio of 250 : 1, 30 °C reaction temperature, and 10 atm ethylene in the
2
C6/Et AlCl system.
2
2
.3.3. Effect of ligand substituents on catalytic behavior. To compare the influence of
the ligand on the catalytic behavior of the nickel pre-catalysts, chloride pre-catalysts
C1–C16 were investigated under the optimized reaction conditions Et AlCl/Ni molar ratio
2
of 250 : 1, 30 °C, and 10 atm ethylene, and the data are presented in table 3. The sub-
1
2
stituents on the quinoline (R ) and benzoimidazole (R ) moieties of the ligand affected the
catalytic behavior of the nickel complexes and the oligomer distribution. In the series of
1
2
pre-catalysts with R = Me (entries 4–8, table 3), with the exception of C5 with R = H, the
2
2
2
i
activity order C6 (R = Me) > C7 (R = Et) > C8 (R = Pr) seemed to be governed by the
steric hindrance of the ligands and the electron-donating features of the alkyl substituents.
Specifically, bulky substituents occupying the space around nickel hinder the coordination
of ethylene. This is contradictory to the slow insertion of ethylene on electron-rich active
species in catalytic systems with late-transition metals [16,58,59]. The same trend of cat-
1
alytic activities was observed in the series of nickel pre-catalysts with R = H, Et, or i-Pr,
2
respectively. Therefore, the electronic effect was a major issue caused by the substituent R
because R is too far removed from the active nickel center.
2
a
Table 3. Ethylene oligomerization by C1–C16.
c
Oligomer distribution (%)
b
Entry
Cat.
Activity
α–C
4
C4
C6
1
2
3
4
5
6
7
8
9
C1
C2
C3
C4
C5
C6
C7
C8
1.88
1.96
1.63
1.55
2.22
3.12
1.88
1.59
2.89
3.13
2.00
1.67
2.99
3.25
2.34
1.77
88.2
84.1
82.1
79.2
84.2
78.2
77.6
78.8
77.7
76.5
75.5
88.0
84.0
80.1
79.3
84.2
93.2
94.0
93.1
93.2
93.5
93.9
93.1
93.5
93.4
93.5
93.8
94.0
94.1
93.7
93.2
93.5
6.8
6.0
6.9
6.8
6.5
6.1
6.9
6.5
6.6
6.5
6.2
6.0
5.9
6.3
6.8
6.5
C9
1
0
C10
C11
C12
C13
C14
C15
C16
1
1
1
1
1
1
1
2
3
4
5
6
a
2 2 4
Conditions: 5 μmol Ni, 250 equiv. Et AlCl, 10 atm C H , 20 min, 100 mL of toluene.
b
c
−1
−1
Activity, mol (Ni) h
.
Determined by GC, ∑C denotes the total amount of oligomers.

3
830
X. Wei et al.
a
Table 4. Nobornene polymerization with C1–C12/MAO.
Yield
(g)
Conversion
(%)
b
Run
Cat.
Activity
1
2
3
4
5
6
7
8
9
C1
C2
C3
C4
C5
C6
C7
C8
2.55
2.77
2.18
2.40
2.42
2.32
1.64
2.51
2.98
3.09
2.40
3.21
1.98
1.79
2.03
2.22
3.06
3.32
2.62
2.87
2.90
2.79
1.96
3.01
3.58
3.71
2.87
3.85
2.39
2.15
2.43
2.66
52.0
56.5
44.6
48.9
49.4
47.5
33.5
51.2
60.8
63.0
48.9
65.5
40.6
36.5
41.4
45.3
C9
1
0
C10
C11
C12
C13
C14
C15
C16
1
1
1
1
1
1
1
2
3
4
5
6
a
Conditions: 2.5 μmol Ni, MAO, Al : Ni : NB = 1000 : 1 : 20,000, total volume 30 mL, 20 °C,
0 min, toluene as solvent.
2
b
−1
−1
mol (Ni) h
.
1
With regard to the influence of the R substituents on the catalytic performances of the
2
nickel complexes, shown with the series of nickel complexes with R = Me, the catalytic
1
activities were in the following order: R = iPr (C14) > Et (C10) > Me (C6) > H (C2). This
is consistent with the slow insertion of ethylene on the electron-rich active species in
late-transition metal catalytic systems [16,59]. Beyond the electronic influence on explain-
1
ing the better activities, more bulky substituents could protect the active species as R = iPr
2
(
C14) > Et (C10) > Me (C6) > H (C2). Other series of nickel pre-catalysts with R = H, Et,
or i-Pr also exhibited the same trend in their catalytic activities. In general, the main
products were butenes with good selectivity toward α-butene reaching 88%.
2
.4. Vinyl polymerization of norbornene
Although specific applications of polynorbornene remain scarce, there is interest in the use
of nickel pre-catalysts in the polymerization of norbornene [54–56]. Thus, the catalytic
behaviors of C1–C16 were investigated in the polymerization of norbornene (NB) using
toluene as the solvent, and the results are shown in table 4. Upon fixing the Al : Ni : NB
molar ratio to 1000/1/20,000, all nickel pre-catalysts showed higher activities at 20 °C, with
6
−1
−1
C12 exhibiting an activity of 3.85 × 10 g mol (Ni) h and a conversion of 65.5%.
3
. Conclusion
The preparation of catalyst is very important in the polymerization of organic monomers
1
2
[
60]. R and R showed different influences on the activities of the nickel complexes;
therefore, fine-tuning the ligands would potentially control the catalytic activities of nickel
pre-catalysts and resultant oligomers, and polymer of norbornene. The LNiCl complexes
2

Nickel(II) complexes for ethylene oligomerization
3831
displayed good catalytic activities in the oligomerization of ethylene, and the substituents
6
and reaction parameters affect the catalytic behavior. Activities as high as 3.25 × 10
−
1
−1
g (mol Ni)
h
were attained using a Al/Ni molar ratio of 250 at 30 °C under 10 bar
ethylene. Furthermore, the nickel complexes displayed high activities in the vinyl polymer-
ization of norbornene upon activation with MAO.
4
4
. Experimental
.1. General considerations
All manipulations involving air and moisture-sensitive compounds were carried out under
an atmosphere of dried and purified nitrogen using standard Schlenk and vacuum-line tech-
niques. Toluene was dried over sodium metal and distilled under nitrogen. Methylaluminox-
ane (MAO, 1.46 M solution in toluene) and modified methylaluminoxane (MMAO, 1.93 M
in heptane) were purchased from Akzo Nobel Corp. Diethylaluminium chloride (Et AlCl,
2
1
.70 M in toluene), triethylaluminium (AlEt , 2.00 M in heptane), ethylaluminium
3
sesquichloride (Et Al Cl , 0.87 M in toluene), and other reagents were purchased from
3
2
3
Acros Chemicals. FT-IR spectra were recorded on a Perkin–Elmer System 2000 FT-IR
spectrometer. Elemental analysis was carried out using a Flash EA 1112 microanalyzer. GC
analyses were performed using a Varian CP-3800 gas chromatograph equipped with a flame
ionization detector and a 30 m (0.2 mm i.d., 0.25-μm film thickness) CP-Sil 5 CB column.
4
.2. Syntheses and characterizations
L1 A mixture of 2-methylquinoline (1.43 g, 10 mmol), benzene-1,2-diamine (1.08 g,
0 mmol), and PPA (1.43 g, 10 mmol) was refluxed for 12 h at 170 °C. The eluted fraction
1
was collected and concentrated to give L1 as a yellow solid in a 43% yield. δ (400 MHz;
H
CDCl ; Me Si) 10.96 (1H, s), 8.56 (1H, d, J = 8.1 Hz), 8.32 (1H, d, J = 8.6 Hz), 8.11 (1H,
3
4
d, J = 8.5 Hz), 7.89 (2H, t, J = 11.3 Hz), 7.75 (1H, t, J = 10.2 Hz), 7.58 (1H, t, J = 10.0 Hz),
.49 (1H, d, J = 7.8 Hz), 7.29–7.33 (2H, m), 4.46 (3H, s, –CH ). δ (100 MHz; CDCl ;
7
3
C
3
Me Si) 151.1, 148.5, 147.6, 144.6, 137.5, 134.2, 130.4, 129.0, 128.7, 128.0, 127.4, 124.3,
4
1
22.8, 120.4, 119.4, 111.4. Anal. Calcd for C H N (245.28): C, 78.35; H, 4.52; N, 17.13.
16 11 3
−
1
Found: C, 78.25; H, 4.72; N, 17.00. FT-IR (diamond disk, cm ): 3047, 1652, 1597, 1496,
1
444, 1414, 1317, 1233, 1105, 867, 829, 737.
L2 A mixture of quinoline-2-carbaldehyde (1.57 g, 10.0 mmol), N-methyl-2-nitroben-
zenamine (1.52 g, 10.0 mmol), Na S O (3.20 g), and DMF : H O (3 : 1) was refluxed for
2
2
4
2
1
2 h. The solvent was evaporated on a rotary evaporator and the resulting solid was eluted
with petroleum ether on an alumina column. The second fraction was collected and concen-
trated to give L2 as a yellow solid in 46% yield. δ (400 MHz; CDCl ; Me Si) 8.55 (1H,
H
3
4
d, J = 8.6 Hz), 8.28 (1H, d, J = 8.6 Hz), 8.16 (1H, d, J = 8.6 Hz), 7.87 (2H, t, J = 10.9 Hz),
7
4
1
.76 (1H, t, J = 10.1 Hz), 7.59 (1H, t, J = 10.1 Hz), 7.48 (1H, d, J = 7.8 Hz), 7.35 (2H, m),
.46 (3H, s, –CH ). δ (100 MHz; CDCl ; Me Si) 150.4, 149.8, 147.1, 142.6, 137.5, 136.3,
29.6, 129.5, 127.6, 127.5, 127.1, 123.5, 122.6, 121.6, 120.2, 110.0, 32.99. Anal. Calcd for
3
C
3
4
C H N (259.31): C, 78.74; H, 5.05; N, 16.20. Found: C, 78.64; H, 5.15; N, 16.10. FT-
1
7 13 3
−
1
IR (diamond disk, cm ): 3047, 1616, 1598, 1466, 1446, 1390, 1332, 1211, 1115, 1053,
008, 838, 764, 734.
1

3
832
X. Wei et al.
L3 In a manner similar to that described for L2, L3 was prepared as a yellow solid in
6% yield. δH (400 MHz; CDCl ; Me Si) 8.57 (1H, d, J = 8.6 Hz), 8.28 (1H, d,
3
3
4
J = 8.6 Hz), 8.14 (1H, d, J = 8.4 Hz), 7.88 (2H, m), 7.76 (1H, t, J = 10.1 Hz), 7.59 (1H, t,
J = 10.1 Hz), 7.48 (1H, d, J = 7.8 Hz), 7.37 (1H, t, J = 9.3 Hz), 7.33 (1H, t, J = 9.2 Hz),
5
.02–5.07 (2H, m, –CH –), 1.64 (3H, t, J = 9.5 Hz, –CH ). δ (100 MHz; CDCl ; Me Si)
2 3 C 3 4
1
1
50.4, 149.6, 147.4, 142.9, 136.6, 136.4, 129.7, 127.7, 127.2, 123.6, 122.7, 121.8, 120.4,
10.1, 40.96, 15.47. Anal. Calcd for C H N (273.33): C, 79.10; H, 5.53; N, 15.37.
1
8 15 3
−
1
Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk, cm ): 3046, 1598, 1560, 1467,
1
396, 1329, 1257, 1189, 1117, 1067, 827, 758, 734.
L4 In a manner similar to that described for L2, L4 was prepared as a yellow solid in
9% yield. δH (400 MHz; CDCl ; Me Si) 8.43 (1H, d, J = 8.6 Hz), 8.30 (1H, d,
2
3
4
J = 8.6 Hz), 8.14 (1H, d, J = 8.4 Hz), 7.89 (2H, m), 7.71–7.78 (2H, m), 7.60 (1H, t,
J = 7.8 Hz), 7.32 (1H, t, J = 9.3 Hz), 7.30 (1H, t, J = 9.2 Hz), 5.02–5.07 (2H, m, –CH –),
2
1
1
2
.64 (3H, t, J = 9.5 Hz, –CH ). δ (100 MHz; CDCl ; Me Si) 150.9, 150.4, 147.2, 143.6,
3 C 3 4
36.6, 134.9, 129.9, 129.8, 127.8, 127.7, 127.3, 123.0, 122.6, 122.3, 120.7, 113.1, 49.12,
1.44. Anal. Calcd for C H N (287.36): C, 79.41; H, 5.96; N, 14.62. Found: C, 78.64;
1
9 17 3
−1
H, 5.15; N, 16.10. FT-IR (diamond disk, cm ): 2969, 1596, 1494, 1390, 1255, 1114, 833,
7
65, 742.
L5 In a manner similar to that described for L1, L5 was prepared as a yellow solid in
7% yield. δ (400 MHz; CDCl ; Me Si) 10.65 (1H, s), 8.52 (1H, d, J = 8.6 Hz), 8.27 (1H,
4
H
3
4
d, J = 8.6 Hz), 7.89 (1H, d, J = 8.4 Hz), 7.76 (1H, t, J = 9.9 Hz), 7.59 (1H, t, J = 10.0 Hz),
7
.46 (1H, t, J = 9.8 Hz), 7.32 (2H, m), 2.87 (3H, s, –CH ). δ (100 MHz; CDCl ; Me Si)
3 C 3 4
1
51.4, 151.0, 146.6, 145.0, 137.5, 137.2, 136.6, 130.3, 128.6, 127.1, 125.9, 124.4, 120.3,
19.7, 118.7, 111.4, 18.08. Anal. Calcd for C H N (259.31): C, 78.74; H, 5.05; N,
1
1
1
1
7 13 3
−
1
6.20. Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk, cm ): 2921, 1596, 1491,
413, 1314, 837, 736.
L6 In a manner similar to that described for L2, L6 was prepared as a yellow solid in
3% yield. δH (400 MHz; CDCl ; Me Si) 8.60 (1H, d, J = 8.6 Hz), 8.24 (1H, d,
4
3
4
J = 8.6 Hz), 7.90 (1H, d, J = 8.4 Hz), 7.66 (1H, d, J = 8.0 Hz), 7.54 (1H, d, J = 7.0 Hz),
.46 (2H, m), 7.34 (2H, t, J = 7.3 Hz), 4.50 (3H, s, –CH ), 2.87 (3H, s, –CH ). δ
C
7
3
3
(
100 MHz; CDCl ; Me Si) 150.3, 149.3, 146.4, 142.7, 137.5, 136.8, 129.9, 127.7, 127.0,
3 4
1
25.7, 123.6, 122.6, 121.4, 120.2, 110.0, 33.39, 18.48. Anal. Calcd for C H N (273.33):
18 15 3
C, 79.10; H, 5.53; N, 15.37. Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk,
−
1
cm ): 2915, 1600, 1568, 1490, 1413, 1388, 1330, 1205, 1055, 843, 764, 733.
L7 In a manner similar to that described for L2, L7 was prepared as a yellow solid in
3
9% yield. δH (400 MHz; CDCl ; Me Si) 8.59 (1H, d, J = 8.6 Hz), 8.26 (1H, d,
3 4
J = 8.6 Hz), 7.89 (1H, d, J = 8.6 Hz), 7.71 (1H, d, J = 8.0 Hz), 7.61 (1H, d, J = 7.0 Hz),
7
1
1
1
.48 (2H, m), 7.35 (2H, t, J = 7.3 Hz), 5.04–5.07 (2H, m, –CH –), 2.83 (3H, s, –CH ),
2 3
.59 (3H, m, –CH ). δC (100 MHz; CDCl ; Me Si) 149.6, 149.3, 146.6, 142.8, 137.5,
3
3
4
36.8, 136.6, 130.0, 127.7, 127.0, 125.7, 123.6, 122.6, 121.6, 120.3, 110.0, 40.92, 18.45,
5.54. Anal. Calcd for C H N (287.36): C, 79.41; H, 5.96; N, 14.62. Found: C, 78.64;
1
9 17 3
−
1
H, 5.15; N, 16.10. FT-IR (diamond disk, cm ): 2969, 1599, 1571, 1398, 1371, 1325,
1
257, 1189, 1127, 1074, 841, 766, 746.
L8 In a manner similar to that described for L2, L8 was prepared as a yellow solid in
8% yield. δH (400 MHz; CDCl ; Me Si) 8.47 (1H, d, J = 8.6 Hz), 8.29 (1H, d,
1
3
4
J = 8.6 Hz), 7.89 (1H, d, J = 8.4 Hz), 7.71 (2H, t, J = 10.0 Hz), 7.59 (1H, d, J = 7.0 Hz),
.49 (1H, t, J = 9.8 Hz), 7.31 (2H, m), 6.57–6.45 (1H, m, –CH–), 2.82 (3H, s, –CH ), 1.80
7
3
(
6H, d, J = 7.6, 2×–CH ). δ (100 MHz; CDCl ; Me Si) 150.5, 149.7, 146.3, 143.6, 137.5,
3 C 3 4

Nickel(II) complexes for ethylene oligomerization
3833
1
1
37.0, 134.9, 130.0, 127.7, 127.2, 125.8, 122.9, 122.4, 122.2, 120.7, 113.1, 49.10, 21.49,
8.26. Anal. Calcd for C H N (301.38): C, 79.70; H, 6.35; N, 13.94. Found: C, 78.64;
2
0 19 3
−
1
H, 5.15; N, 16.10. FT-IR (diamond disk, cm ): 2956, 1601, 1474, 1435, 1387, 1325, 1211,
1
055, 840, 758, 736.
L9 In a manner similar to that described for L1, L9 was prepared as a yellow solid in
3% yield. δ (400 MHz; CDCl ; Me Si) 10.51 (1H, s), 8.52 (1H, d, J = 8.5 Hz), 8.29 (1H,
4
H
3
4
d, J = 8.5 Hz), 7.90 (1H, d, J = 7.4 Hz), 7.71 (1H, d, J = 8.0 Hz), 7.61 (2H, t, J = 8.6 Hz),
.51 (1H, t, J = 10.1 Hz), 7.34 (2H, d, J = 8.3 Hz), 3.39–3.45 (2H, m, –CH –), 1.47 (3H, t,
7
2
J = 10.1 Hz, –CH ). δ (100 MHz; CDCl ; Me Si) 151.6, 146.9, 146.0, 144.7, 142.9,
3
C
3
4
1
37.7, 134.1, 128.8, 128.6, 127.3, 125.9, 124.3, 122.8, 120.4, 118.7, 111.4, 24.54, 15.25.
Anal. Calcd for C H N (273.33): C, 79.10; H, 5.53; N, 15.37. Found: C, 78.64; H, 5.15;
1
8 15 3
−
1
N, 16.10. FT-IR (diamond disk, cm ): 2959, 1597, 1495, 1411, 1313, 1227, 842, 740.
L10 In a manner similar to that described for L2, L10 was prepared as a yellow solid in
4
0% yield. δH (400 MHz; CDCl ; Me Si) 8.59 (1H, d, J = 8.6 Hz), 8.25 (1H, d,
3 4
J = 8.6 Hz), 7.89 (1H, d, J = 7.5 Hz), 7.70 (1H, d, J = 8.0 Hz), 7.61 (1H, d, J = 6.9 Hz),
.49 (2H, t, J = 6.5 Hz), 7.35 (2H, t, J = 7.3 Hz), 4.89 (3H, s, –CH ), 3.33–3.39 (2H, m, –
7
3
CH –), 1.64 (3H, t, J = 9.4 Hz, –CH ), 1.43 (3H, t, J = 9.9 Hz, –CH ). δ (100 MHz;
2
3
3
C
CDCl ; Me Si) 150.1, 149.3, 145.6, 143.1, 142.6, 137.5, 136.8, 128.2, 127.7, 127.1, 125.6,
3
4
1
23.5, 122.6, 121.3, 120.2, 109.9, 33.17, 24.91, 15.02. Anal. Calcd for C H N (287.36):
19 17 3
C, 79.41; H, 5.96; N, 14.62. Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk,
−
1
cm ): 2924, 1602, 1475, 1438, 1390, 1367, 1321, 1211, 1058, 850, 735.
L11 In a manner similar to that described for L2, L11 was prepared as a yellow solid in
3
5% yield. δH (400 MHz; CDCl ; Me Si) 8.62 (1H, d, J = 8.6 Hz), 8.27 (1H, d,
3 4
J = 8.2 Hz), 7.89 (1H, d, J = 7.3 Hz), 7.72 (1H, d, J = 8.0 Hz), 7.62 (1H, d, J = 8.6 Hz),
.54 (2H, t, J = 6.5 Hz), 7.35 (2H, t, J = 7.3 Hz), 5.10–5.15 (2H, m, –CH –), 3.28–3.39
7
2
(
2H, m, –CH –), 1.64 (3H, t, J = 9.4 Hz, –CH ), 1.42 (3H, t, J = 9.9 Hz, –CH ). δ
2 3 3 C
(
100 MHz; CDCl ; Me Si) 149.7, 149.4, 145.8, 143.2, 142.9, 136.9, 136.5, 128.4, 127.9,
3 4
1
27.2, 125.7, 123.6, 122.7, 121.7, 120.3, 110.0, 40.79, 24.76, 15.60, 15.41. Anal. Calcd for
C H N (301.38): C, 79.70; H, 6.35; N, 13.94. Found: C, 78.64; H, 5.15; N, 16.10. FT-
2
0 19 3
−
1
IR (diamond disk, cm ): 2927, 1601, 1441, 1396, 1371, 1324, 1188, 1055, 842, 764, 729.
L12 In a manner similar to that described for L2, L12 was prepared as a yellow solid in
2
8% yield. δH (400 MHz; CDCl ; Me Si) 8.47 (1H, d, J = 8.6 Hz), 8.29 (1H, d,
3 4
J = 8.6 Hz), 7.90 (1H, d, J = 8.6 Hz), 7.71 (2H, m), 7.61 (1H, d, J = 7.0 Hz), 7.52 (2H, m),
.32 (2H, t, J = 7.3 Hz), 6.64–6.53 (1H, m, –CH–), 3.33 (2H, m, –CH –), 1.80 (6H, d,
7
2
J = 7.0 Hz, 2×–CH ), 1.41–1.37 (3H, m, –CH ). δ (100 MHz; CDCl ; Me Si) 150.3,
3
3
C
3
4
1
1
49.7, 145.5, 143.8, 143.0, 137.1, 135.0, 128.6, 127.8, 127.3, 125.8, 125.7, 123.1, 122.4,
20.8, 113.2, 48.96, 25.07, 24.58, 21.32, 15.58, 15.13. Anal. Calcd for C H N (315.41):
2
1 21 3
C, 79.97; H, 6.71; N, 13.32. Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk,
−
1
cm ): 2959, 1598, 1465, 1449, 1399, 1372, 1330, 1175, 854, 763, 734.
L13 In a manner similar to that described for L1, L13 was prepared as a yellow solid in
4
5% yield. δ (400 MHz; CDCl ; Me Si) 10.52 (1H, s), 8.52 (1H, d, J = 8.3 Hz), 8.30 (1H,
H 3 4
d, J = 8.0 Hz), 7.90 (1H, d, J = 7.0 Hz), 7.71 (1H, d, J = 7.4 Hz), 7.67 (1H, d, J = 8.5 Hz),
.62 (1H, d, J = 6.5 Hz), 7.56 (1H, t, J = 7.3 Hz), 7.34 (2H), 4.48 (1H, m, –CH–), 1.46
6H, 2 × CH ). δC (100 MHz; CDCl ; Me Si) 151.6, 147.3, 146.8, 145.4, 144.7, 137.8,
7
(
3
3
4
1
34.1, 128.8, 127.4, 126.0, 125.7, 124.3, 122.8, 120.4, 118.6, 111.4, 27.44, 23.71.
Anal. Calcd for C H N (287.36): C, 79.41; H, 5.96; N, 14.62. Found: C, 78.64; H,
1
9 17 3
−
1
5
7
.15; N, 16.10. FT-IR (diamond disk, cm ): 2955, 1598, 1496, 1413, 1312, 1276, 840,
63, 741.

3
834
X. Wei et al.
L14 In a manner similar to that described for L2, L14 was prepared as a yellow solid in
1% yield. δH (400 MHz; CDCl ; Me Si) 8.59 (1H, d, J = 8.6 Hz), 8.27 (1H, d,
4
3
4
J = 8.6 Hz), 7.90 (1H, d, J = 7.8 Hz), 7.71 (1H, d, J = 8.0 Hz), 7.67 (1H, d, J = 7.1 Hz),
.56 (1H, t, J = 10.1 Hz), 7.49 (1H, d, J = 7.8 Hz), 7.39–7.31 (2H, m), 4.40 (1H, m, –
CH–), 1.44 (3H, d, J = 7.2, 2 × CH ). δ (100 MHz; CDCl ; Me Si) 150.5, 149.3, 147.6,
7
3
C
3
4
1
3
45.2, 142.7, 137.6, 137.2, 127.9, 127.4, 125.7, 125.6, 123.7, 122.7, 121.5, 120.3, 110.0,
3.31, 27.72, 23.56. Anal. Calcd for C H N (301.38): C, 79.70; H, 6.35; N, 13.94.
2
0 19 3
−
1
Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk, cm ): 2952, 1598, 1568, 1481,
1
412, 1303, 1280, 1228, 1121, 865, 839, 740.
L15 In a manner similar to that described for L2, L15 was prepared as a yellow solid in
4% yield. δH (400 MHz; CDCl ; Me Si) 8.61 (1H, d, J = 8.6 Hz), 8.27 (1H, d,
3
3
4
J = 8.6 Hz), 7.88 (1H, d, J = 7.6 Hz), 7.70 (1H, d, J = 8.1 Hz), 7.67 (1H, d, J = 7.0 Hz),
.58–7.50 (2H, m), 7.38–7.31 (2H, m), 5.15–5.09 (2H, m, –CH –), 4.43–4.36 (1H, m, –
7
2
CH–), 1.62 (3H, t, J = 9.5 Hz, –CH ), 1.43 (6H, d, J = 7.2 Hz, 2×–CH ). δ (100 MHz;
3
3
C
CDCl ; Me Si) 149.9, 149.5, 147.6, 145.4, 142.9, 137.2, 136.6, 128.0, 127.4, 125.7, 123.7,
3
4
1
22.7, 121.8, 120.4, 110.1, 40.84, 27.43, 23.80, 15.71. Anal. Calcd for C H N (315.41):
21 21 3
C, 79.97; H, 6.71; N, 13.32. Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk,
−
1
cm ): 2991, 1599, 1466, 1415, 1388, 1343, 1180, 1131, 1016, 844, 743.
L16 In a manner similar to that described for L2, L16 was prepared as a yellow solid in
2
0% yield. δH (400 MHz; CDCl ; Me Si) 8.47 (1H, d, J = 8.6 Hz), 8.29 (1H, d,
3 4
J = 8.6 Hz), 7.89 (1H, d, J = 7.6 Hz), 7.74 (2H, m), 7.67 (1H, d, J = 7.0 Hz), 7.54 (1H, t,
J = 10.0), 7.33–7.31 (2H, m), 6.61–6.56 (1H, m, –CH–), 4.38–4.32 (1H, m, –CH–), 1.79
(
6H, d, J = 7.5 Hz, –CH ), 1.43 (6H, d, J = 7.2 Hz, 2×–CH ). δ (100 MHz; CDCl3;
3 3 C
Me Si) 150.5, 149.7, 147.5, 145.1, 143.7, 137.3, 134.9, 127.9, 127.4, 125.6, 123.0, 122.4,
4
1
22.3, 120.8, 113.7, 49.00, 27.64, 23.62, 22.83, 21.49. Anal. Calcd for C H N (329.44):
22 23 3
C, 80.21; H, 7.04; N, 12.76. Found: C, 78.64; H, 5.15; N, 16.10. FT-IR (diamond disk,
−
1
cm ): 2961, 1600, 1456, 1425, 1388, 1333, 1179, 1131, 1015, 844, 737.
C1 In a Schlenk tube with 10 mL of dried ethanol, L1 (0.245 g, 1.0 mmol) and
NiCl ·6H O (0.236 g, 1.0 mmol) were added, and the mixture was stirred for 12 h at room
2
2
temperature. Absolute diethyl ether (10 mL) was added to precipitate the complex. The pre-
cipitate was washed with diethyl ether and dried under vacuum to obtain C1 as a yellow
powder in 83% yield. Calcd for C H Cl N Ni (374.88): C, 51.26; H, 2.96; N, 11.21%.
1
6
11
2 3
−
1
Found: C, 51.16; H, 3.03; N, 11.09%. FT-IR (diamond; cm ): 3345, 1622, 1596, 1507,
1
430, 1319, 1145, 832, 740.
C2 In a manner similar to that described for C1, C2 was prepared as a yellow powder in
6% yield. In comparison with the FT-IR spectra of the free organic compounds, the
8
absorption bands of the complexes were shifted to lower frequencies, suggesting coordina-
tion effects. Anal. Calcd for C H Br N Ni (388.90): C, 52.50; H, 3.37; N, 10.80%.
1
7
13
2 3
+
Found: C, 52.35; H, 3.43; N, 10.73%. EIMS m/z 440.87[M] (23), 234(20), 200(40), 80
100). FT-IR (diamond; cm ): 3051, 1591, 1474, 1410, 1348, 1140, 1101, 827, 744.
−
1
(
C3 In a manner similar to that described for C1, C3 was prepared as a yellow powder in
8
5% yield. Anal. Calcd for C H Cl N Ni (402.93): C, 53.65; H, 3.75; N, 10.43%. Found:
18 15 2 3
−
1
C, 53.50; H, 3.85; N, 10.32%. FT-IR (diamond; cm ): 2976, 1591, 1524, 1500, 1424,
1
338, 1141, 827, 758, 740.
C4 In a manner similar to that described for C1, C4 was prepared as a yellow powder in
2% yield. Anal. Calcd for C H Cl N Ni (416.96): C, 54.73; H, 4.11; N, 10.08%. Found:
C, 54.58; H, 4.24; N, 10.00%. FT-IR (diamond; cm ): 3328, 1589, 1463, 1427, 1337,
162, 832, 747.
8
1
9
17
2 3
−
1
1

Nickel(II) complexes for ethylene oligomerization
3835
C5 In a manner similar to that described for C1, C5 was prepared as a yellow powder in
9
1% yield. Anal. Calcd for C H Cl N Ni (388.90): C, 52.50; H, 3.37; N, 10.80%. Found:
1
7
13
2 3
−
1
C, 52.40; H, 3.52; N, 10.68%. FT-IR (diamond; cm ): 3052, 1598, 1478, 1419, 1320, 839,
7
56.
C6 In a manner similar to that described for C1, C6 was prepared as a yellow powder in
7% yield. Anal. Calcd for C H Cl N Ni (402.93): C, 53.65; H, 3.75; N, 10.43%. Found:
8
1
8
15
2 3
−
1
C, 53.55; H, 3.87; N, 10.31%. FT-IR (diamond; cm ): 3336, 1593, 1474, 1400, 1349,
152, 831, 757.
1
C7 In a manner similar to that described for C1, C7 was prepared as a yellow powder in
8
3% yield. Anal. Calcd for C H Cl N Ni (416.96): C, 54.73; H, 4.11; N, 10.08%. Found:
1
9
17
2 3
−1
C, 54.56; H, 4.29; N, 10.00%. FT-IR (diamond; cm ): 3351, 1590, 1445, 1348, 1157, 845,
7
42.
C8 In a manner similar to that described for C1, C8 was prepared as a yellow powder in
2% yield. Anal. Calcd for C H Cl N Ni (430.98): C, 55.74; H, 4.44; N, 9.75%. Found:
8
2
0
19
2 3
−
1
C, 55.56; H, 4.55; N, 9.65%. FT- IR (diamond; cm ): 3042, 1594, 1479, 1413, 1320, 840,
7
52.
C9 In a manner similar to that described for C1, C9 was prepared as a yellow powder in
9% yield. Anal. Calcd for C H Cl N Ni (402.93): C, 53.65; H, 3.75; N, 10.43%. Found:
8
1
8
15
2 3
−
1
C, 53.55; H, 3.87; N, 10.32%. FT-IR (diamond; cm ): 3342, 1590, 1533, 1429, 1351,
163, 857, 734.
1
C10 In a manner similar to that described for C1, C10 was prepared as a yellow powder
in 90% yield. Anal. Calcd for C H Cl N Ni (416.96): C, 54.73; H, 4.11; N, 10.08%.
1
9
17
2 3
−
1
Found: C, 54.56; H, 4.22; N, 10.00%. FT-IR (diamond; cm ): 3332, 1591, 1531, 1437,
1
349, 1163, 846, 744.
C11 In a manner similar to that described for C1, C11 was prepared as a yellow powder
in 86% yield. Anal. Calcd for C H Cl N Ni (430.98): C, 55.74; H, 4.44; N, 9.75%.
2
0
19
2 3
−
1
Found: C, 55.62; H, 4.56; N, 9.65%. FT-IR (diamond; cm ): 3368, 1600, 1567, 1397,
1
371, 1188, 1056, 842, 765, 729.
C12 In a manner similar to that described for C1, C12 was prepared as a yellow powder
in 83% yield. Anal. Calcd for C H Cl N Ni (445.01): C, 56.68; H, 4.76; N, 9.44%.
2
1
21
2 3
−
1
Found: C, 56.54; H, 4.83; N, 9.34%. FT-IR (diamond; cm ): 3256, 1594, 1545, 1390,
1
345, 1189, 1052, 840, 765, 739.
C13 In a manner similar to that described for C1, C13 was prepared as a yellow powder
in 87% yield. Anal. Calcd for C H Cl N Ni (416.96): C, 54.73; H, 4.11; N, 10.08%.
1
9
17
2 3
−
1
Found: C, 54.57; H, 4.24; N, 10.00%. FT-IR (diamond; cm ): 3325, 1600, 1496, 1412,
1
312, 838, 738.
C14 In a manner similar to that described for C1, C14 was prepared as a yellow powder
in 91% yield. Anal. Calcd for C H Cl N Ni (430.98): C, 55.74; H, 4.44; N, 9.75%.
2
0
19
2 3
−
1
Found: C, 55.64; H, 4.54; N, 9.70%. FT-IR (diamond; cm ): 2959, 1598, 1436, 1356,
1
212, 1056, 839, 743.
C15 In a manner similar to that described for C1, C15 was prepared as a yellow powder
in 89% yield. Anal. Calcd for C H Cl N Ni (445.01): C, 56.68; H, 4.76; N, 9.44%.
2
1
21
2 3
−
1
Found: C, 56.55; H, 4.87; N, 9.35%. FT-IR (diamond; cm ): 3351, 1592, 1527, 1458,
1
353, 1129, 841, 775, 741.
C16 In a manner similar to that described for C1, C16 was prepared as a yellow powder
in 87% yield. Anal. Calcd for C H Cl N Ni (459.04): C, 57.56; H, 5.05; N, 9.15%.
2
2
23
2 3
−
1
Found: C, 57.43; H, 5.14; N, 9.10%. FT-IR (diamond; cm ): 2992, 1590, 1530, 1454,
353, 1119, 842, 770, 731.
1

3
836
X. Wei et al.
4
.3. General procedure for ethylene oligomerization
Ethylene oligomerization under 10 bar ethylene was carried out in a stainless steel autoclave
0.25 L capacity) equipped with a mechanical stirrer, temperature controller, and gas ballast
(
through a solenoid clave for the continuous feeding of ethylene at a constant pressure. The
catalyst precursor was dissolved in 50 mL toluene in a Schlenk tube stirred with a magnetic
stirrer and was injected into the reactor under an ethylene flux. The co-catalyst EtAlCl and
2
5
0 mL toluene were added. When the required reaction temperature was reached, ethylene
was introduced at the desired pressure to begin the reaction. After the reaction mixture was
stirred for the desired period of time, the reaction was stopped and about 1 mL of the reac-
tion solution was collected, and the reaction was terminated by the addition of 10% aqueous
hydrogen chloride. The organic layer was analyzed by gas chromatography (GC) to
determine the composition and mass distribution of the obtained oligomers.
4
.4. General procedure for norbornene polymerization
Typically, 2.5 μmol of the nickel complex was dissolved in a Schlenk tube with 15.0 mL
distilled toluene under nitrogen, and 14.3 mL of norbornene in toluene (3.50 M, 50.0 mmol
of norbornene) was added via syringe. The polymerization was initiated by adding 1.72 mL
Table 5. Crystal data and structure refinement for C2·CH
3
CH
2
OH.
Crystal color
Empirical formula
fw
Yellow
2 3
18Cl N
19
C H
NiO
433.97
293(2)
0.71073
Triclinic
P1
9.2114(18)
9.801(2)
14.085(3)
75.91(3)
89.89(3)
82.04(3)
1220.8(4)
2
T (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
α (°)
β (°)
γ (°) 3
V (Å )
Z
D
μ (mm
−
3
Calcd (mg m
)
1.181
1.023
−
1
)
F(0 0 0)
446
Cryst. size (mm)
θ range (°)
0.09 × 0.08 × 0.07
1.49–27.48
Limiting indices
−11 ≤ h ≤ 11
−
−
12 ≤ k ≤ 12
18 ≤ l ≤ 17
No. of rflns. collected
No. unique rflns. [R(int)]
Completeness to θ (%)
Abs. corr.
13,450
5409(0.0359)
96.7
None
Data/restraints/parameters
Goodness-of-fit on F
5409/0/236
1.064
2
Final R indices [I > 2σ(I)]
R1 = 0.0698
wR2 = 0.1914
R1 = 0.0742
wR2 = 0.1953
0.629 and −0.891
R indices (all data)
−
3
Largest diff. peak and hole (e Å
)

Nickel(II) complexes for ethylene oligomerization
3837
−1
of toluene containing 1.46 mol L MAO (2.5 mmol). After 20 min, the polymerization
was terminated by injecting 200 mL of acidic ethanol (ethanol : HCl (conc.) = 95 : 5) into
the reactor. Polynorbornene was isolated by filtration, washed with ethanol, and dried under
vacuum at 60 °C for 12 h.
4
.5. Crystal structure determinations
Single crystals of C2·CH CH OH, suitable for X-ray diffraction studies, were obtained by
3
2
slow diffusion of diethyl ether into methanolic solution. Diffraction data for
C2·CH CH OH were collected on a Rigaku Saturn724+ CCD with graphite-monochro-
3
2
mated Mo-Kα radiation (l = 0.71073 Å). Cell parameters were obtained by the global
refinement of the positions of all the collected reflections. Intensities were corrected for Lor-
entz and polarization effects in addition to empirical absorption. Data were collected using
phi scans and the structures were solved by direct methods (SIR97) using SHELX97 [61],
2
and the refinement was carried out by full-matrix least squares on F . All non-hydrogen
atoms were refined anisotropically. Crystal data and processing parameters for
C2·CH CH OH are summarized in table 5.
3
2
Supplementary material
CCDC 981264 contain the supplementary crystallographic data for the complexes
C2·CH CH OH. These data can be obtained free of charge via http://www.ccdc.cam.ac.
3
2
uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Center, 12 Union
Road, Cambridge CB2 1EZ, UK; Fax: (+44) 1223-336-033; or E-mail: deposit@ccdc.cam.
ac.uk. Supplementary data associated with this article can be found in the online version.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This work was supported by National Natural Science Foundation of China [grant number 51474061]; Natural
Science Foundation of Hebei Province [grant number B2014501120], [grant number E2013501035], [grant number
E2013501135]; Program for New Century Excellent Talents in University [grant number NCET-10-0304]; Special
Fund for Basic Scientific Research of Central Colleges, Northeastern University [grant number N100123003],
[
grant number N120523001]; Fund for the Scientific Research of Northeastern University at Qinhuangdao [grant
number XNK201506]; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical
Technology.
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