T. Amaya et al. / Tetrahedron Letters 48 (2007) 2729–2732
Table 1. Oxidative coupling of 2,6-di-t-butylphenol
2731
guchi, S.; Fukuhara, S. Synth. Met. 1999, 106, 67–70; (e)
Hirao, T.; Fukuhara, S.; Otomaru, Y.; Moriuchi, T.
Synth. Met. 2001, 123, 373–376; (f) Moriuchi, T.; Bandoh,
S.; Miyaishi, M.; Hirao, T. Eur. J. Inorg. Chem. 2001, 651–
657; (g) Moriuchi, T.; Miyaishi, M.; Hirao, T. Angew.
Chem. Int. Ed. 2001, 40, 3042–3045; (h) Shen, X.;
Moriuchi, T.; Hirao, T. Tetrahedron Lett. 2004, 45,
Bu-t
OH
Bu-t
t-Bu
O
Bu-t
O
Bu-t
O
5
mol%cat.
+
O
DMF, O ,
2
o
80
C, 24 h
t-Bu
Bu-t
Bu-t
4
5
6
4
733–4736.
a
Entry Catalyst Diameter Dispersity
nm)
Yield (%)
4
. (a) Hirao, T.; Higuchi, M.; Hatano, B.; Ikeda, I. Tetra-
hedron Lett. 1995, 36, 5925–5928; (b) Higuchi, M.;
Yamaguchi, S.; Hirao, T. Synlett 1996, 1213–1214.
(
4
5
6
1
2
PANI/
Pd 2b
PANI/
Pd 3
PANI
1–4
5–15
—
Good
0
Quant
0
3
b
5. (a) Feng, W.; Sun, E.; Fujii, A.; Wu, H.; Niihara, K.;
Yoshino, K. Bull. Chem. Soc. Jpn. 2000, 73, 2627–2633;
Partially
aggregated
—
15 78
(
(
b) Xia, H.; Wang, Q. Chem. Mater. 2002, 14, 2158–2165;
c) Li, X.; Chen, W.; Bian, C.; He, J.; Xu, N.; Xue, G.
3
4
8
65
12
c
Appl. Surf. Sci. 2003, 217, 16–22; (d) Li, X.; Wang, G.; Li,
X.; Lu, D. Appl. Surf. Sci. 2004, 229, 395–401.
PVP/Pd 2–7
Good
50 39
Trace
a
1
0
0
Determined by H NMR with an internal standard (1,1 ,2,2 -
tetrabromoethane).
6. (a) Tsakova, V.; Borissov, D. Electrochem. Commun. 2000,
2, 511–515; (b) Sharma, S.; Nirkhe, C.; Pethkar, S.;
Athawale, A. A. Sens. Actuators B 2002, 85, 131–136; (c)
Athawale, A. A.; Bhagwat, S. V. J. Appl. Polym. Sci. 2003,
b
c
Prepared by the reduction with NaBH
4
.
Prepared according to Ref. 15.
8
9, 2412–2417.
7
. (a) Wang, J.; Neoh, K. G.; Kang, E. T. J. Colloid Interface
Sci. 2001, 239, 78–86; (b) Sarma, T. K.; Chowdhury, D.;
Paul, A.; Chattopadhyay, A. Chem. Commun. 2002, 1048–
decrease in the yield of 5 (entry 2). In the absence of Pd
nanoparticle, 5 and quinone 6 were obtained in 65% and
1
2% yield, respectively (entry 3). On the other hand,
1
049; (c) Chen, F.; Xu, G.-Q.; Andy Hor, T. S. Mater.
1
5
when the polyvinylpyrrolidone nanoparticle, PVP/Pd
Lett. 2003, 57, 3282–3286; (d) Tian, S.; Liu, J.; Zhu, T.;
Knoll, W. Chem. Commun. 2003, 2738–2739; (e) Sarma, T.
K.; Chattopadhyay, A. J. Phys. Chem. A 2004, 108, 7837–
was used instead of PANI/Pd nanoparticle, the yield
was lower (entry 4).
7
2
842; (f) Tian, S.; Liu, J.; Zhu, T.; Knoll, W. Chem. Mater.
004, 16, 4103–4108; (g) Tseng, R. J.; Huang, J.; Ouyang,
In summary, the pre-organization of the Pd(II) species
on PANI through complexation is effective to synthesize
the well-dispersed and small-sized nanoparticle. The
present method is considered to be generally applicable
to other p-conjugated compound/metals nanoparticles,
and even heterometallic nanoparticles. PANI/Pd nano-
particle is expected to serve as an efficient redox catalyst
in various oxidative reactions.
J.; Kaner, R. B.; Yang, Y. Nano Lett. 2005, 5, 1077–1080;
h) Majumdar, G.; Goswami, M.; Sarma, T. K.; Paul, A.;
(
Chattopadhyay, A. Langmuir 2005, 21, 1663–1667.
. Huang, J.; Virji, S.; Weiller, B. H.; Karner, R. B. Chem.
Eur. J. 2004, 10, 1314–1319.
8
9
. (a) Drelinkiewicz, A.; Hasik, M.; Kloc, M. J. Catal. 1999,
186, 123–133; (b) Drelinkiewicz, A.; Hasik, M.; Kloc, M.
Catal. Lett. 2000, 64, 41–47; (c) Wang, J. G.; Neoh, K. G.;
Kang, E. T. Appl. Surf. Sci. 2003, 218, 231–244; (d)
Athawale, A. A.; Bhagwat, S. V.; Katre, P. P.; Chandwad-
kar, A. J.; Karandikar, P. Mater. Lett. 2003, 57, 3889–3894;
Acknowledgments
(
e) Park, J.-E.; Park, S.-G.; Koukitu, A.; Hatozaki, O.;
Oyama, N. Synth. Met. 2004, 141, 265–269; (f) Houdayer,
A.; Schneider, R.; Billaud, D.; Ghanbaja, J.; Lambert, J.
Appl. Organometal. Chem. 2005, 19, 1239–1248.
The authors thank Professors K. Niihara and T. Sekino,
and Dr. S. Seino at Osaka University for TEM analysis.
D.S. expresses his special thanks for the center of excel-
lence (21COE) program ‘Creation of Integrated Eco-
Chemistry’ of Osaka University.
1
0. Experimental procedure: To a stirred solution of poly-
aniline (142.5 mg) in THF (100 mL) was dropwise added a
solution of Pd(OAc) (58.4 mg) in THF (100 mL) at room
2
temperature over 30 min under argon. The reaction
mixture was stirred at room temperature for 1 h. The
appeared precipitation was collected by filtration through
a membrane filter, washed with THF, and dried in vacuo
to give PANI/Pd(II) complex 1 (174.3 mg, 87%) as a dark
Supplementary data
ꢀ1
blue solid: IR (KBr)/cm 3266, 3025, 1589, 1506, 1307,
ꢀ4
1
6
156, 821; UV–vis, kmax (2.0 · 10 M; THF)/nm 301,
79.
1
1
1. Alcohol reduction method for the synthesis of Pd nano-
particles: Yonezawa, T.; Toshima, N. J. Chem. Soc.,
Faraday Trans. 1995, 91, 4111–4119.
References and notes
. For a comprehensive review, see: Gangopadhyay, R.; De,
2. Experimental procedure: To a stirred suspension of PANI/
Pd(II) complex 1 (65 mg) in THF (50 mL), treated with
sonication prior to the reaction, was dropwise added a
solution of sodium borohydride (35.6 mg) in ethanol
(10 mL) at 0 ꢁC over 10 min under argon. After stirring
for 1 h at the same temperature, the reaction mixture was
concentrated in vacuo. The residue was dispersed into ice-
cooled deionized water with sonication. The suspension
was filtered through a membrane filter. The residue was
1
A. Chem. Mater. 2000, 12, 608–622.
2
3
. Hirao, T. Coord. Chem. Rev. 2002, 226, 81–91.
. (a) Hirao, T.; Higuchi, M.; Ikeda, I.; Ohshiro, Y. J.
Chem. Soc., Chem. Commun. 1993, 194–195; (b) Higuchi,
M.; Imoda, D.; Hirao, T. Macromolecules 1996, 29, 8277–
8
279; (c) Hirao, T.; Yamaguchi, S.; Fukuhara, S. Tetra-
hedron Lett. 1999, 40, 3009–3012; (d) Hirao, T.; Yama-