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Catalysis Science & Technology
+
1
-n-butyl-3-methylimidazolium (1.0 g, 4.4 mmol) was added.
(C14). ESI/MS(+): m/z calculated for [C17
H
19
N
4
]
279.1604;
o
The mixture was stirred for 10 minutes and then the organic
solvent was removed by reduced pressure. Then, the reactor was
loaded with 4 bar of hydrogen and heated for specific times and
temperatures depending on the type of ligand employed. The
found 279.1622. TGA: Tdec. = 353 C.
DOI: 10.1039/C4CY01116C
60
Synthesis of the ionophilic ligand L3
5
In a drybox, 1-allyl-2,3-dimethyl-imidazolium NTf
2
(1.540 g,
[
Pd(0)]
n
-NPs in the ionic liquid were analysed by transmission
3.69 mmol), HPiPr (1.242 g, 10.51 mmol), CF Ph (3 mL) and
2
3
electronic microscopy and used for the catalytic experiments.
1,1’-azobis(cyclohexanecarbonitrile) (ABCN) (48 mg, 0.20
mmol) were combined in a resalable Schlenk flask. The mixture
was stirred at 80 ºC for 5 days, during which time an additional
ABCN charge (48 mg, 0.20 mmol) was added to the reaction
mixture. The reaction mixture was then washed with ethyl ether
(3 × 10 mL). The volatiles were removed by oil pump vacuum to
Typical procedure for hydrogenation
6
5
In a typical experiment, the reactor with the freshly prepared
1
0
n
[Pd(0)] -NPs was loaded with the substrate (10 mmol) and the
o
reaction was heated at 40 C for the given reaction times (see
Table 2). Samples were analysed periodically by GC.
yield a viscous liquid; 1.98g (80%).
1
70
H NMR (300 MHz, DMSO-d
6
) δ ppm 7.68 (d, J = 2.1 Hz, NCH)
), 3.74 (s,
CH N), 2.58 (s, CH C), 1.87-1.77 (m, CH CH P), 1.69 (m,
Synthesis of the ionophilic ligand L1
e 7.61 (d, J = 2.1 Hz, NCH), 4.15 (t, J = 7.4 Hz, NCH
2
In a typical synthesis, 2,2’-dimethyl-4,4’-bipyridine (2.00 g,
10.90 mmol) was stirred with selenium dioxide (1.90 g, 10.90
3
3
2
2
1
3
1
2
2
3
3
4
5
0
5
0
5
0
3 2 2 3
CH CH), 1.36-1.30 (m, CH CH P), 1.01 (m, CH CH). C NMR
o
mmol) in 60 mL of dioxane. The reaction was heated at 100 C
6
(75 MHz, DMSO-d ) δ ppm 145.0 (s, NCN), 123.0 e 121.5 (s,
−
3
for 16 h. After that, the mixture was filtered and the dioxane was 75 NCH), 120.2 (q, JCF = 321.7 Hz, NTf ), 49.1 (d, J = 14.1 Hz,
2
CP
2
evaporated. Next, sodium borohydride (2.0 g, 0.05 mol) and 100
mL of methanol were added and the mixture was stirred at room
temperature for 16 h. The volume was reduced to 25 mL, water
was added and the crude product was extracted with chloroform
NCH ), 35.4 (s, CH N), 28.8 (d, J
= 20.5 Hz, CH CH CH ),
2
3
CP
2
2
2
2
23,5 (d, JCP = 12.9 Hz, CH CHP), 20.6 (d, J
3
CP
= 15.7 Hz,
2
CH CHP) e 19.4 (d, J = 9.7 Hz, CH CHP), 18.2 (d, J = 18.8
3
CP
3
CP
3
1
Hz, CH P), 9,9 (s, CH C). P NMR (121 MHz, DMSO-d ) δ
3 × 10 mL). At the end the product was purified by column 80 ppm 2.8 (s). ESI/MS(+): m/z calculated for [C H N P]
14 28 2
2
3
6
+
(
chromatography (alumina) resulting in (2-(4-methylpyridin-2-
yl)pyridin-4-yl)methanol in 46% yield over two steps. Then, this
alcohol was stirred with methanesulphonyl chloride (0.80 g, 6.50
mmol) and triethylamine (0.80 g, 7.50 mmol) in 20 mL of
255.1985; found 255.4022.
Acknowledgements
o
dichloromethane for 1 h at 25 C. Then, the mixture was filtered
We thank CAPES for providing a fellowship and INCT-Catálise
for partial financial support.
through a neutral alumina plug and the solution was concentrated
to 5 mL. Next, a solution of 1,2-dimethyl-1H-imidazole (0.80 g,
8.50 mmol) in 20 mL of acetonitrile was added and the mixture
o
was stirred for 16 h at 25 C. The solvent was then evaporated 85 Notes and references
and the resulting solid was washed with ethyl ether (3 x 10 mL).
Finally, a solution of potassium hexafluorophosphate (1.90 g,
a
Laboratory of Molecular Catalysis, Institute of Chemistry, Universidade
Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970
Porto Alegre, RS, Brazil. Fax: +55 51 33087304; Tel: +55 51 33086321;
E-mail: jairton.dupont@ufrgs.br
1
0.00 mmol) in 20 mL of water was added, yielding a pale pink
solid. The solid was filtered and dried under vacuum, furnishing
b
90
Centro de Tecnologias Estratégicas do Nordeste—CETENE, 50740-540
1
.85 g of L1 (global yield: 40%).
Recife, PE, Brazil and Universidade Federal de Pernambuco- Programa
de Pós-Graduação em Ciência de Materiais - UFPE —PGMTR, 50670-
90, Recife, PE, Brazil
† Electronic Supplementary Information (ESI) available: Details of NMR
spectra and TEM are given. See DOI: 10.1039/b000000x/
1
H NMR (300 MHz, DMSO-d
.52 (d, J = 4.9 Hz, H6’), 8.38 (s, H3), 8.24 (s, H3’), 7.36 (d, J =
5.1 Hz, H5), 7.26 (d, J = 4,9 Hz, H5’), 5.54 (t, J = 5.8 Hz, H9),
6
) δ ppm 8.59 (d, J = 5.1 Hz, H6),
8
95
1
3
1.
J. P. Hallett and T. Welton, Chem. Rev., 2011, 111, 3508-
576.
4
.63 (d, J = 5.8 Hz, H8), 2.40 (s, H7).
C
3
6
RMN (75 MHz, DMSO-d ) δ ppm 155.9 (C2
2
.
J. D. Scholten, B. C. Leal and J. Dupont, ACS Catal., 2012, 2,
184-200.
e C2’), 153.5 (C4), 149.7 e 149.6 (C6 e C6’),
48.6 (C4’), 125.6 (C5’), 122.0 e 121.9 (C5 e
1
1
1
1
00 3.
I. Favier, D. Madec, E. Teuma and M. Gomez, Curr. Org.
Chem., 2011, 15, 3127-3174.
1
4
5
C3’), 118.5 (C3), 62.4 (C8), 21.4 (C7).
4
.
C. Pan, K. Pelzer, K. Philippot, B. Chaudret, F. Dassenoy, P.
Lecante and M. J. Casanove, J. Am. Chem. Soc., 2001, 123,
7584.
1
6
H NMR (300 MHz, DMSO-d ) δ
05 5.
J. L. Pellegatta, C. Blandy, V. Colliere, R. Choukroun, B.
Chaudret, P. Cheng and K. Philippot, J. Mol. Catal. A: Chem.,
ppm 8.69 (d, J = 5.1 Hz, H6), 8.54
d, J = 4.9 Hz, H6’), 8.30 (s, H3),
(
2
002, 178, 55.
50
8.23 (s, H3’), 7.77 (d, J = 2.1 Hz,
H13), 7.70 (d, J = 2.1 Hz, H12),
6
.
J. D. Aiken and R. G. Finke, J. Am. Chem. Soc., 1999, 121,
8803.
10 7.
A. Roucoux, J. Schulz and H. Patin, Chem. Rev., 2002, 102,
7
.33-7.26 (m, H5 e H5’), 5.59 (s,
H8), 3.78 (s, H15), 2.57 (s, H14),
.41 (s, H7). C NMR (75 MHz, DMSO-d ) δ ppm 155.8 (C2’),
154.4 (C2), 149.9 (C6), 149.0 (C6’), 148.1 (C4’), 145.1 (C10),
3
757-3778.
D. Astruc, F. Lu and J. R. Aranzaes, Angew. Chem. Int. Ed.,
005, 44, 7852-7872.
8
.
1
3
2
6
2
5
5
9.
J. Dupont and J. Scholten, Chem. Soc. Rev., 2010, 39, 1780-
15
1804.
1
1
44.6 (C4), 125.2 (C5’), 122.9 (C12), 122.2 (C5), 121.5 (C13),
21.3 (C3’), 118.9 (C3), 49.5 (C8), 34.9 (C15), 20.6 (C7), 9.4
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