Self-Immobilized Neutral Nickel Catalysts Bearing Allyl Groups
FULL PAPER
fluxing with appropriate drying agents (sodium/benzophenone for
toluene, benzene, diethyl ether, THF, and hexane; CaH2 for
dichloromethane; magnesium for methanol) and distilled under
argon prior to use. H NMR spectra were recorded with a Varian
Unity-400 spectrometer. NMR multiplicities are abbreviated as fol-
(20 mL), the sodium salt of the corresponding ligand was obtained.
A solution containing the sodium salt of B (0.629 g, 1.5 mmol) and
trans-[Ni(PPh3)2(Ph)Cl] (1.0 g, 1.44 mmol) in benzene (20 mL) was
stirred at room temp. After 6 h, the reaction mixture was separated
by filtration to remove NaCl. Hexane was slowly added to the top
of the filtrate. Complex 2 was obtained as a yellow-orange solid.
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lows: s ϭ singlet, d ϭ doublet, q ϭ quadruplet, m ϭ multiplet,
br ϭ broad. IR spectra of the complexes were measured with a Yield: 0.95 g (83%). 1H NMR (400 MHz, C6D6): δ ϭ 8.13 (d, 1 H,
Bio-Rad FTS135 spectrometer. EI-MS spectra were recorded with
a Finnigan MAT 8500 spectrometer (electron energy 70 eV) and
NϭCH), 7.89Ϫ6.34 (m, 30 H, Ar-H), 6.02 (m, 1 H, CHϭ), 5.11
(m, 2 H, ϭCH2), 4.23 (m, 2 H, CHMe2), 3.32 (d, JH,H ϭ 6.4, 2 H,
elemental analyses were performed with a PerkinϪElmer Series II CH2), 1.35 (d, JH,H ϭ 6.8 Hz, 6 H, CH3), 1.27 (d, JH,H ϭ 6.8 Hz,
CHN/O Analyzer 2400. The 13C NMR spectroscopic data for poly- 6 H, CH3) ppm. EI-MS: m/z ϭ 717 [M Ϫ Ph]ϩ, 455 [M Ϫ Ph Ϫ
ethylene were obtained using o-dichlorobenzene as the solvent with PPh3]ϩ. C52H50NNiOP (794.64): calcd. C 78.60, H 6.34, N 1.76;
an FX-100 NMR spectrometer at 130 °C. The intrinsic viscosity
[η] was measured in decalin at 135 °C using an Ubbelohde visco-
meter. The viscosity average molecular weight (Mν) was calculated
by the following equation [η] ϭ 67.7·10Ϫ3 Mν0.67. Average molecu-
lar weight (Mw) and molecular weight distribution (Mn/Mw) values
of polyethylene products were determined using a PL GPC-220 gel
permeation chromatograph at 150 °C using a narrow standards
calibration and equipped with three PL gel columns (sets of PL gel
10 µm MIXED-B LS). Trichlorobenzene was employed as a solvent
at a flow rate of 1.00 mL/min. Melting points were determined by
DSC with a PerkinϪElmer 7 Series Thermal Analysis System. The
starting materials 3-tert-butyl-5-methylbenzaldehyde and 3-phenyl-
benzaldehyde,[20] 3,5-dinitrobenzaldehyde,[21] 4-allyl-2,6-dimeth-
ylaniline,[22] trans-[Ni(PPh3)2(Ph)Cl][23] and complex 1[13] were pre-
found C 78.88, H 6.22, N 1.73.
Complex 3: Ligand C as a yellow solid in 90% yield. 1H NMR
(CDCl3, 400 MHz): δ ϭ 13.71 (s, 1 H, OH), 8.39 (s, 1 H, NϭCH),
7.69Ϫ7.01 (m, 8 H, Ar-H), 6.93 (s, 2 H, CϭNϪArϪH), 5.98(m, 1
H, CCHϭC), 5.09(q, 2 H, CϭCH2), 3.37(d, 2 H, CH2CϭC), 2.19(s,
6 H, CH3). 3 as a red crystalline solid. Yield: 0.95 g (86%). 1H
NMR (400 MHz, C6D6): δ ϭ 8.07 (d, JP,H ϭ 8.4 Hz, 1 H, NϭCH),
7.78Ϫ6.44 (m, 30 H, Ar-H), 6.01 (m, 1 H, CHϭ), 5.10 (d, JH,H
ϭ
1.6, 2 H, ϭCH2), 3.19 (d, JH,H ϭ 6.4 Hz, 2 H, CH2), 2.53 (s, 6 H,
CH3) ppm. EI-MS: m/z ϭ 662 [M Ϫ Ph]ϩ, 400 [M Ϫ Ph Ϫ PPh3]ϩ.
C48H42NNiOP (738.53): calcd. C 78.06, H 5.73, N 1.90; found C
77.99, H 5.73, N 1.91.
Complex 4: Ligand D as yellow-gold crystals in 95% yield. 1H
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pared according to literature procedures and characterized by H
NMR spectra. Other commercially available reagents were pur-
chased and used without purification.
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NMR (CDCl3, 400 MHz): δ ϭ 16.27 (s, 1 H, OH), 9.07 (s, JP,H
ϭ
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3.2 Hz, 1 H, NϭCH), 8.50 (s, JH,H ϭ 2.8 Hz, 1 H, Ar-H), 8.26 (s,
1 H, Ar-H), 7.10 (s, 2 H, CϭNϪArϪH), 5.97 (m, 1 H, CCHϭC),
5.16 (q, 2 H, CϭCH2), 3.43 (d, 2 H, CH2CϭC), 2.95 (m, 2 H,
CHMe2), 1.24 (d, 12 H, CH3 of iPr). 4 as a red solid. Yield: 1.05 g
General Procedure for Ethylene Polymerization: A 500-mL auto-
clave was charged with 100 mL of toluene under argon. A solution
of the self-immobilized nickel() complex (10Ϫ65 µmol) in toluene
(20 mL) was added. After three times of ethylene gas exchange, the
ethylene pressure was raised to the specified value and maintained
for a certain time. The polymerization was terminated by the ad-
dition of methanol and dilute HCl (10%). The solid polyethylene
was filtered, washed with methanol and dried at 40 °C in vacuo.
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(90%). H NMR (400 MHz, C6D6): δ ϭ 8.34 (d, JH,P ϭ 2.8 Hz, 1
H, NϭCH), 7.84Ϫ6.34 (m, 24 H, Ar-H), 6.02 (m, 1 H, CHϭ), 5.12
(m, 2 H, ϭCH2), 3.96 (m, 2 H, CHMe2), 3.28 (d, JH,H ϭ 6.0, 2 H,
CH2), 1.29 (d, JH,H ϭ 6.8 Hz, 6 H, CH3), 1.12 (d, JH,H ϭ 6.8 Hz,
6 H, CH3) ppm. EI-MS: m/z ϭ 807 [Mϩ], 545 [M Ϫ PPh3]ϩ.
C46H44N3NiO5P (808.53): calcd. C 68.33, H 5.48, N 5.20; found C
68.97, H 5.41, N 5.10.
Preparation of Complex 2. (a) Ligand Synthesis: 4-Allyl-2,6-diiso-
proylaniline was prepared from 2,6-diisoproylaniline by an anal-
ogous method according to ref.[22] The colorless liquid product was
collected at 98.5 °C/0.6 Torr in 35% yield. 1H NMR(400 MHz,
CDCl3): δ ϭ 6.85 (s, 2 H, H-Ar), 5.98 (m, 1 H, CHϭC), 5.09 (d,
1 H, CϭCH(E)), 5.03 (d, 1 H, CϭCH(Z)), 3.6 (br, 2 H, NH2), 3.30
(d, 2 H, CH2CϭC), 2.92 [m, 2 H, CH(Me)2], 1.26 [d, 12 H,
C(CH3)2]. Formic acid (0.25 mL) was added to a methanol solution
(5 mL) containing 4-allyl-2,6-diisopropylphenylamine (1.302 g,
6.0 mmol) and 3-phenylbenzaldehyde (1.148 g, 5.8 mmol). After
stirring at room temperature for 12 h, the reaction mixture was
poured into distilled water (25 mL), extracted with diethyl ether (25
mL ϫ 2), washed with deionized water (25 mL ϫ 2) and dried
overnight with anhydrous sodium sulfate. After the solvent was re-
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Complex 5: Ligand E as a yellow-green oil in 92% yield. H NMR
(CDCl3, 400 MHz): δ ϭ 13.41 (s, 1 H, OH), 8.12 (s, 1 H, NϭCH),
7.26Ϫ6.98 (m, 4 H, Ar-H), 6.02 (m, 1 H, CCHϭC), 5.10 (q, 2 H,
CϭCH2), 3.39 (d, 2 H, CH2CϭC), 2.99 (m, 2 H, CHMe2), 2.32 (s,
3 H, CH3Ar), 1.48 (s, 9 H, CH3 of tBu), 1.16 (d, 12 H, CH3 of
iPr). 5 as a yellow-orange solid. Yield: 0.92 g (81%). 1H NMR
(400 MHz, C6D6): δ ϭ 8.10 (d, 1 H, NϭCH), 7.90Ϫ6.34 (m, 24 H,
Ar-H), 6.04 (m, 1 H, CCHϭC), 5.11 (q, 2 H, CϭCH2), 4.45 (m, 2
H, CH of iPr), 3.32 (d, 2 H, CH2CϭC), 2.32 (s, 3 H, CH3ϪAr),
1.36 (d, 6 H, CH3 of iPr), 1.36 (d, 6 H, CH3) 1.26 (d, 12 H, CH3
of iPr), 1.09 (s, 9 H, CH3 of tBu) ppm. EI-MS: m/z ϭ 787 [M]ϩ.
C51H56NNiOP (788.67): calcd. C 77.67, H 7.16, N 1.78; found C
77.90, H 7.03, N 1.88.
moved by rotary evaporation a yellow solid was separated and X-ray Crystal Structure Determination of Complex 4: The crystallo-
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dried under vacuum to afford 2.187 g of B in 95% yield. H NMR
(CDCl3, 400 MHz): δ ϭ 13.68 (s, 1 H, OH), 8.35 (s, 1 H, NϭCH), single crystals were grown in toluene/hexane (1:1) at Ϫ15 °C. The
7.71Ϫ7.05 (m, 8 H, ArϪH), 7.00 (s, 2 H, CϭNϪArϪH), 6.00 (m, crystal was sealed in a thin-walled glass capillary under argon. The
graphic data for 4 (4a/4b) are summarized in Table 5. Dark-red
1 H, CCHϭC), 5.11 (q, 2 H, CϭCH2), 3.39 (d, 2 H, CH2CϭC), intensity data were collected at 293 K with a Siemens P4 dif-
˚
2.99 (m, 2 H, CHMe2), 1.16 (d, 12 H, CH3 of iPr). (b) Complex fractometer using Mo-Kα radiation (λ ϭ 0.71073 A, graphite
Synthesis: Sodium hydride (0.2 g, 5 mmol) was added to a solution
of the ligand B (0.596 g, 1.5 mmol) in THF (20 mL). The mixture
was stirred at room temp. for 2 h, and then centrifuged after which
the upper clear solution was transferred and concentrated in vacuo
to afford a pale-yellow solid residue. After washing with hexane
monochromator). The stability of the primary beam was controlled
by monitoring three check reflections every 100 reflections. Correc-
tions for absorption based on the ψ-scan technique were applied.
The structure was solved by direct methods using the SHELXTL-
97 program and refined by full-matrix least-squares on F2o using
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