Pd Nanoparticles immobilized on Fe3O4 @ Poly(ethylene glycol) bridged amine
functionalized imidazolium ionic liquid: A magnetically separable catalyst for
Heck Reaction in water
Xiang Liu a, Xiaohua Zhao b,* and Ming Lu a,*
a
School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
b
School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China. E-mail: zhao12_19@163.com
Supporting Materials
Content
General .……………………………………….………………………S2
Typical Procedure for the Product….………………….……………… S2
Characterization Data of The Product..………………….…………… S3
References .……………………………………….……………….…S17
General:
All materials were purchased from common commercial sources and used without further
purification. 1H NMR spectra were recorded at 400 MHz using TMS as internal standard. Mass
spectroscopy data were collected on an MS-EI instrument.
All the reactions were carried out in air and all products were isolated by chromatography on a
silica gel (300-400 mesh) column using petroleum ether or the mixture of petroleum and ethyl
acetate.
Preparation of Fe3O4 NPs
Initially, FeSO4·7H2O and FeCl3·4H2O were dissolved in water in 1:2 molar ratios under nitrogen
protection. The resulting dark orange solution was stirred for 30 min at 60 °C. An aqueous NaOH
solution (25%) was then added dropwise to the above hot solution with stirring over a period of 10
min. Instant color change from dark orange to black was found to occur with particle formation.
Stirring was continued for further 30 min followed by cooling to room temperature. The solvent
was removed by magnetic decantation. Washing of the particles was done several times with
water to make the iron dispersion free of any residual salts, which was used during the
coprecipitation.
Preparation of PEG4000 bridged amine functionalized imidazolium ionic liquid
(a) Synthesis of PEG-4000 dichloride (1): To a solution of PEG-4000 (100 g, 0.025 mol) and
pyridine (4.0 mL, 0.05 mol) in CH2Cl2 (250mL) was dropped SOCl2 (4.0 mL, 0.055 mol) at
ambient temperature. The reaction mixture was stirred at ambient temperature for 12 h. After
completion, the solvent was evaporated in vacuum. The residue was then dissolved in CH2Cl2
(150 mL) and washed with water (3×50 mL). After the solvent was evaporated, the
intermediate 1 was obtained and used directly for the next reaction.
(b) Synthesis of PEG-4000 bridged di-imidazolium compound (2): Imidazole (8.2 g, 0.12 mol)
was melted at around 100℃ and NaOH (4 g, 0.1 mol) was added. After the solid NaOH
thawed, toluene (50 mL) was added and heated to remove water by azeotropy for 3 h. Then,
toluene was evaporated off under reduced pressure. Subsequently, the solution of intermediate
1 in CH3CN (150 mL) was added. The mixture was stirred at 70 ℃ for 12 h. After removal
of solvent, the residue obtained was dissolved in CH2Cl2 (100 mL) and washed with water
(3×50 mL). After concentration, 80 g of the desired compound 2 was obtained, yield 89%.
(c) PEG4000 bridged amine functionalized imidazolium ionic liquid (3): A mixture of (2) and
4-Bromobutylamine hydrobromide in toluene (200 mL) was stirred at 70 oC for 48 h. An oily
liquid gradually precipitated from the toluene solution along with the reaction. After
completion, the solvent was removed in vacuum and the residue was washed repeatedly with
ethyl acetate, followed by evaporation under reduced pressure to yield yellow oil.
Subsequently, KPF6 (9.6 g) and CH2Cl2 (50 mL) were added and the mixture was stirred at
ambient temperature for 48 h. After filtration and removal of solvent, 3 was obtained. 1H
NMR (500 MHz, d-DMSO, ppm)
9.25 (s, 2H), 7.83 (s, 2H), 7.78 (s, 2H), 4.37-4.33 (m,
4H), 4.21 (t, J = 7.2 Hz, 4H), 3.79-3.75 (m, 4H), 3.67-3.28 (m, 428H), 2.70 (t, J = 7.2 Hz, 4H),
1.84 (dt, J = 14.8, 7.3 Hz, 4H), 1.45 (dt, J = 14.6, 7.3 Hz, 4H); 13C NMR (126 MHz, d-DMSO,
ppm)
136.88, 123.32, 122.65, 70.23, 70.06, 69.99, 68.56, 49.30, 48.72, 27.07, 26.04; IR
(cm-1) 3421, 2865, 1563, 1453, 1348, 1297, 1250, 1088, 946, 844, 757, 643, 546
Fig s1
Fig. s1 FT-IR spectra for Fe3O4 NPs (a), PEG-AIm-NH2-IL (b) and Fe3O4@PEG-AIm-NH2-IL-Pd (c)
Fig s2
Fig.s2 TGA-DSC curves of the as-prepared Fe3O4@PEG-AIm-NH2-IL-Pd.
Fig s3
Fig.s3 EDS spectrum of the fifth cycled Fe3O4@PEG-AIm-NH2-IL-Pd.
General conditions for Heck reactions
Aryl halide (1.0 mmol), alkene (2.0 mmol), base (2.0 mmol), and 0.005 mmol of palladium (0.105
mmol g-1) were added to the vessel with 3 mL water. The mixture was continuously stirred at
80 °C for the desired time until complete consumption of the starting aryl halide. The reaction
progress was monitored by GC. After magnetic separation of the catalyst, the product was
extracted with diethyl ether and purified by column chromatography. The magnetically recovered
catalyst was washed three times with ethanol and dried in vacuum. For recycling experiments,
new portions of substrates and base were added. All the products were characterized by 1H NMR
and 13C NMR.
Characterization Data of the Products
Modle reaction
(E)-Stilbenze
White solid; m.p. 123-124 oC; 1H NMR (500 MHz, CDCl3) δ 7.57 (d,
J = 7.7 Hz, 4H), 7.43-7.40 (m, 4H), 7.33-7.30 (m, 2H), 7.17 (s, 2H); 13C NMR (125
MHz, CDCl3) δ 137.3, 128.7, 127.6, 126.5.
1-methoxy-4-[(1E)-2-phenylethenyl]-benzene
pale yellow plates, 1H-NMR (300 MHz, CDCl3)  3.73 (s, 3H), 6.78 (d,
J = 8.4 Hz, 2H), 6.85 (d, J = 16.4 Hz, 1H), 6.95 (d, J = 16.4 Hz, 1H), 7.12 (t, J = 7.2 Hz, 1H), 7.23
(t, J = 7.2 Hz, 2H), 7.33 (d, J = 8.4 Hz, 2H), 7.37 (d, J = 7.2 Hz, 2H); 13C-NMR (75 MHz, CDCl3)
 55.2, 114.2, 126.4, 126.8, 127.2, 127.8, 128.4, 128.7, 130.3, 137.8, 159.4.
1-[4-(2-phenylethenyl)phenyl]-ethanone
Colorless crystals, 1H-NMR (300 MHz, CDCl3)  2.30 (s, 3H), 7.09
(d, J = 16.4 Hz, 1H), 7.19 (d, J = 16.4 Hz, 1H), 7.26-7.39 (m, 3H), 7.56 (d, J = 8.0 Hz, 2H), 7.59
(d, J = 8.0 Hz, 2H), 7.95 (d, J = 8.0 Hz, 2H); 13C-NMR (100 MHz, CDCl3)  26.3. 126.6, 127.4,
127.6, 128.9, 129.4, 129.5, 131.6, 136.5, 136.9, 142.5, 196.9.
(E)-4-Bromostilbene
Yellow solid; m.p. 137-138 oC; 1H NMR (500 MHz, CDCl3)
δ 7.53-7.48 (m, 4H), 7.41-7.34 (m, 4H), 7.31-7.28 (m, 1H), 7.11 (d, J = 16.3 Hz, 1H),
7.04 (d, J = 16.3 Hz, 1H). 13C NMR (125 MHz, CDCl3) δ 136.9, 136.2, 131.7, 129.4,
128.7, 127.9, 127.9, 127.4, 126.5, 121.3.
(E)-4-Chlromostilbene
white crystals; 1H NMR (500 MHz, CDCl3) δ 7.24-7.53 (m,
9H), 7.04 (s, 2H).
13C
NMR (125 MHz, CDCl3) δ 136.9, 135.7, 133.1, 129.2, 128.7,
128.6, 127.8, 127.6, 127.3, 126.4
1-[4-[(1E)-2-(4-chlorophenyl)ethenyl]phenyl]-ethanone
white crystals; 1H NMR (500 MHz, CDCl3) δ 7.95-7.96
(m, 2H), 7.57-7.59 (d, J = 14.0 Hz 2H), 7.46-7.48 (t, 2H), 7.27-7.36 (m, 2H),
7.12-7.15 (d, J = 15.7 Hz, 2H), 2.62 (s, 3H).
13C
NMR (125 MHz, CDCl3) δ 198.0,
142.3, 136.8, 135.9, 134.6, 130.0, 129.6, 129.2, 128.7, 127.2, 27.3.
1-chloro-4-[(1E)-2-(4-methoxyphenyl)ethenyl]-benzene
1H
NMR (500 MHz, CDCl3) δ 7.32-7.47 (m, 4H),
7.27-7.30 (d, J = 14.0 Hz, 2H), 7.0 (s, 1H), 6.88-6.96 (m, 3H), 3.85 (s, 3H). 13C NMR
(125 MHz, CDCl3) δ 160.2, 136.9, 133.4, 130.5, 129.5, 128.5, 128.0, 126.0, 114.9,
56.0.
1-[2-(4-chlorophenyl)ethenyl]-3-methoxy-benzene
1H
NMR (500 MHz, CDCl3) δ 7.44-7.47 (m, 2H),
7.31-7.37 (m, 2H), 7.06-7.15 (m, 4H), 6.86-6.90 (m, 2H), 3.85 (s, 3H).
13C
NMR
(125 MHz, CDCl3) δ 159.8, 138.3, 135.6, 133.0, 129.3, 128.7, 128.2, 127.6, 119.1,
113.5, 111.8, 55.1.
(E)-2-Methylstilbene
White solid; m.p. 158-159 oC; 1H NMR (500 MHz, CDCl3) δ 7.62
(d, J = 7.4 Hz, 1H), 7.55 (d, J = 7.6 Hz, 2H), 7.40-7.34 (m, 3H), 7.31-7.20 (m, 4H),
7.02 (d, J = 16.2 Hz, 1H), 2.45 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 137.7, 136.4,
135.8, 130.4, 130.0, 128.7, 128.1, 127.6, 127.5, 126.5, 126.2, 125.3, 19.9.
(E)-4-Methylstilbene
White solid; m.p. 120-121 oC; 1H NMR (500 MHz, CDCl3) δ 7.55
(d, J = 7.5 Hz, 2H), 7.46 (d, J = 8.0 Hz, 2H), 7.40 (t, J = 7.6 Hz, 2H), 7.29 (t, J = 7.3
Hz, 1H), 7.21 (d, J = 7.9 Hz, 2H), 7.13 (d, J = 3.8 Hz, 2H), 2.41 (s, 3H).
13C
NMR
(125 MHz, CDCl3) δ 137.5, 134.5, 130.4, 129.4, 128.6, 127.7, 127.4, 126.4, 126.4,
21.2.
Ethyl(E)-cinnamate
Colourless liquid; 1H NMR (500 MHz, CDCl3) δ 7.69 (d, J = 16.0
Hz, 1H), 7.52-7.50 (m, 2H), 7.38-7.36 (m, 3H), 6.43 (d, J = 16.1 Hz, 1H), 4.28-4.24
(m, 2H), 1.35-1.31 (t, J = 7.2 Hz, 3H). 13C NMR (125 MHz, CDCl3) δ 166.9, 144.5,
134.4, 130.1, 128.8, 128.0, 118.2, 60.4, 14.2; MS 177.09.
Ethyl (E)-3-(4-methylphenyl)-2-propenoate
Yellow oil; 1H NMR (400 MHz, CDCl3): δ 1.34 (t, J = 7.2
Hz, 3H),
2.37 (s, 3H), 4.26 (q, J = 7.2 Hz, 2H), 6.39 (d, J = 16.0 Hz, 1H), 7.19 (d, J =
8.0 Hz,2H), 7.42 (d, J = 8.0 Hz, 2H), 7.66 (d, J = 16.0 Hz, 1H); 13C NMR (100 MHz,
CDCl3): 14.5, 21.6, 60.5, 117.3, 128.2, 129.7, 131.8, 140.8, 144.7, 167.4; MS 191.10.
Ethyl (E)-3-(4-acetylphenyl)-2-propenoate
Yellow oil; 1H NMR (400 MHz, CDCl3): δ 1.34 (t, J = 7.2
Hz, 3H),
2.6 (s, 3H), 4.80 (q, J = 7.2 Hz, 2H), 6.52 (d, J = 16.0 Hz, 1H), 7.60 (d, J =
8.4 Hz,2H), 7.69 (d, J = 16.0 Hz, 2H), 7.97 (d, J = 8.0 Hz, 1H); 13C NMR (100 MHz,
CDCl3): 14.3, 26.7, 60.8, 120.9, 128.1, 128.9, 137.98, 138.8, 140.3, 166.5, 197.4;
(2E)-2-Propenoic acid-3-(2-thienyl)-methyl ester
1
H NMR (250 MHz, CDCl3): 7.78 (d, J = 15.8 Hz, 1H), 7.35 (d, J = 5.1 Hz,
1H), 7.23 d, J = 3.6 Hz, 1H), 7.03 (dd, J = 5.1 and 3.6 Hz, 1H), 6.23 (d, J = 15.8 Hz, 1H), 3.77 (s,
3H). 13C NMR (75 MHz, CDCl3) 167.9, 140.2, 137.9, 131.5, 129.1, 128.7, 117.3, 52.3.
Ethyl (E)-3-(4-nitrophenyl)-2-propenoate
Yellow solid; 1H NMR (400 MHz, CDCl3): δ 1.35 (t, J =
7.1 Hz, 3H), 4.1 (q, J = 7.1 Hz, 2H), 6.55 (d, J = 16.0 Hz, 1H), 7.67 (d, J = 8.8 Hz,2H),
7.71 (d, J = 16.4 Hz, 1H), 8.25 (d, J = 8.7 Hz, 1H); 13C NMR (100 MHz, CDCl3): 14.3,
61.1, 122.6, 124.2, 128.6, 140.6, 141.6, 148.5, 166.1.
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2. L. Liu, Y. Zhang and Y. Wang, J. Org. Chem., 2005, 70, 6122.
3. W.-J. Z, K.-H. W, J.-X. Wang, J. Org. Chem. 74 (2009) 5599-5602.
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