Organometallics
Article
0
.25 μm film thickness). Selectivity of α-olefin in oligomers was
polyethylene waxes were collected by filtration, washed with ethanol,
and dried in vacuo at 60 °C to constant weight.
calculated as (amount of α-olefin)/(total amounts of olefin) in
percent. The ligands 2-(benzimidazol-2-yl)-6-(pyrazol-1-yl)pyridine
1
7c
(
(
1
L1),1
2-(benzimidazol-2-yl)-6-(3,5-dimethylpyrazol-1-yl)pyridine
ASSOCIATED CONTENT
Supporting Information
7d
■
L2),
and 2-(N-methylbenzimidazol-2-yl)-6-(3,5-dimethylpyrazol-
1
7d
*
S
-yl)pyridine (L3)
were prepared according to literature
procedures.
.2. Synthesis of 2-(N-Benzylbenzimidazol-2-yl)-6-(3,5-
4
dimethylpyrazol-1-yl)pyridine (L4). A mixture of 2-(benzimida-
zol-2-yl)-6-(3,5-dimethylpyrazol-1-yl)pyridine L2 (0.289 g, 1.00
mmol) and Cs CO (0.65 g, 2.00 mmol) in DMSO (50 mL) was
Distribution of oligomers and characterization of poly-
Crystallographic details for Cr2 and Cr3 (CIF)
2
3
stirred at 80 °C for 30 min and cooled to room temperature. Benzyl
bromide (0.256 g, 1.50 mmol) was added with syringe, and the
mixture was stirred at room temperature. After 3 h, 50 mL of water
was added and the solution was extracted by 20 mL of CH Cl for
2
2
AUTHOR INFORMATION
■
three times. The solvent was removed and the residue was purified by
column chromatography (petroleum ether/ethyl acetate, v/v = 1:2) to
1
give L4 as a white solid (0.368 g, 97.1%). H NMR (500 MHz,
(
CD ) CO) δ: 8.63 (dd, J = 4.5, 1.4 Hz, 1 H, py), 7.98 (dd, J = 7.6, 1.7
Notes
3
2
Hz, 1 H, py), 7.57 (d, J = 7.7 Hz, 1 H, py), 7.46 (dd, J = 7.7, 4.8 Hz, 1
H, Ph), 7.24−7.19 (m, 4 H, Ph), 7.24−7.19 (m, 4 H, Ph), 5.88 (s, 1 H,
pz), 5.17 (s, 2 H, CH ), 2.44 (s, 3 H, CH ), 1.78 (s, 3 H, CH ).
NMR (125 MHz, (CD ) CO) δ: 151.24, 149.70, 149.50, 143.30,
1
1
C, 75.97; H, 5.58; N, 18.46. Found: C, 75.75; H, 5.46; N, 18.21.
.3. Synthesis of Chromium Complexes. General Procedure:
Solid [CrCl (THF) ] was added to a 20 mL THF solution of ligand.
The mixture was stirred overnight at room temperature, and a green
suspension was obtained. The solvent was removed under reduce
pressure. The green powder was collected after being washed with 20
The authors declare no competing financial interest.
13
C
2
3
3
ACKNOWLEDGMENTS
■
3
2
41.94, 141.50, 136.60, 135.38, 128.71, 127.71, 127.01, 122.84, 122.07,
19.73, 110.81, 107.94, 48.13, 13.10, 12.62. Anal. Calcd for C H N :
The project was supported by NSFC No. B040102, the State
Key Laboratory for Modification of Chemical Fibers and
Polymer Materials (Donghua University) No. LK1501, and the
Department of Science and Technology of Qingdao and
Shandong Province Nos. 159181jch and 2015GGX107015.
24
21
5
4
3
3
REFERENCES
■
(
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2
−1
Cr1: green powder in 87%. FT-IR (KBr disk, cm ): 3227, 3120,
1
(
(
1
610, 1484, 1442, 1392, 1171, 1047, 963, 791, 751. Anal. Calcd for
C H Cl CrN : C, 42.93; H, 2.64; N, 16.69. Found: C, 42.70; H,
2
1
5
11
3
5
.58; N, 16.33.
−1
(
Cr2: green powder in 95%. FT-IR (KBr, cm ): 3243, 3073, 1611,
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567, 1493, 1367, 1318, 1127, 990, 807, 759. Anal. Calcd for
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C H Cl CrN : C, 45.61; H, 3.38; N, 15.64. Found: C, 45.43; H,
3
1
7
15
3
5
(
c) Wass, D. F. Dalton Trans. 2007, 816−819. (d) Dixon, J. T.; Green,
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−1
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3
641−3668. (e) Bollmann, A.; Blann, K.; Dixon, J. T.; Hess, F. M.;
1
565, 1493, 1130, 1052, 992, 757. Anal. Calcd for C H Cl CrN : C,
18
17
3
5
Killian, E.; Maumela, H.; McGuinness, D. S.; Morgan, D. H.; Neveling,
A.; Otto, S.; Overett, M.; Slawin, A. M. Z.; Wasserscheid, P.;
Kuhlmann, S. J. Am. Chem. Soc. 2004, 126, 14712−14713. (f) McGuin-
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Bollmann, A.; Maumela, H.; Hess, F.; Englert, U. J. Am. Chem. Soc.
4
6.82; H, 3.71; N, 15.17. Found: C, 46.69; H, 3.66; N, 15.55.
Cr4: green powder in 88%. FT-IR (KBr disk, cm ): 3074, 1610,
−1
1
570, 1444, 1364, 1145, 1040, 990, 749. Anal. Calcd for C H -
2
4
21
Cl CrN : C, 53.60; H, 3.94; N, 13.02. Found: C, 53.49; H, 3.79; N,
3
5
1
2.99.
2
003, 125, 5272−5273. (g) McGuinness, D. S.; Wasserscheid, P.;
4
.4. X-ray Crystallographic Studies. Single crystals of Cr2 and
Keim, W.; Hu, C. H.; Englert, U.; Dixon, J. T.; Grove, C. Chem.
Cr3 were grown by slowly diffusing Et O into their DMF solutions. X-
ray diffraction studies for Cr2 and Cr3 were recorded on a Rigaku
RAXIS Rapid IP diffractometer (graphite-monochromated Mo KR
2
Commun. 2003, 334−335.
(
Mu
̈
̈
4) (a) Peitz, S.; Aluri, B. R.; Peulecke, N.; Muller, B. H.; Wohl, A.;
23
24
radiation). Using Olex2, the structure was solved with the XS and
̈
ller, W.; Al-Hazmi, M. H.; Mosa, F. M.; Rosenthal, U. Chem.Eur.
25
refined with the SHELXL. All the hydrogens were introduced by the
SHELXS-97 procedure and placed in the calculated position. Crystal
data and processing parameters for Cr2 and Cr3 are tabulated in Table
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McGuinness, D. S.; Morgan, D. H. J. Am. Chem. Soc. 2005, 127,
4
. 1494120 and 1494121 were assigned to Cr2 and Cr3 as CCDC
reference numbers, respectively.
.5. General Procedures for Ethylene Oligomerization/
́
10723−10730. (d) van Rensburg, W. J.; Grove, C.; Steynberg, J. P.;
4
Stark, K. B.; Huyser, J. J.; Steynberg, P. J. Organometallics 2004, 23,
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Polymerization. Ethylene oligomerization/polymerization under 10
atm of ethylene pressure was carried out in a 500 mL autoclave steel
reactor. The Cr complex was loaded in a Schlenk tube under N2.
Toluene and cocatalyst (total volume: 100 mL) were introduced by
syringe. The mixture was transferred into the reactor under an
ethylene atmosphere by syringe. When the desired reaction temper-
ature was reached, ethylene at 10 atm pressure was introduced and
maintained during the experiments by a continuous feeding. After a
measured time, a small amount of the catalytic mixture was collected
and immediately quenched by addition of 5% aqueous hydrogen
chloride at 0 °C. The supernatant was analyzed by GC. The remaining
solution was poured into ethanol (containing 5% of HCl), and the
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E
Organometallics XXXX, XXX, XXX−XXX