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coupling reactions of 4-methylphenylboronic acid, with satisfac-
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The recyclability of Pd–Fe–1(H) was further investigated
because the recyclability of the Suzuki catalyst is one of the most
important issues for practical applications. We therefore turned
our attention to the reusability of our Pd catalyst using phe-
nylboronic acid and iodobenzene as model substrates (Table 4).
Aer the model Suzuki coupling reaction was carried out under
the optimized reaction conditions, the catalyst was recovered by
external magnetic separation, washed with ethanol completely,
dried under vacuum and reused for the next run. As shown in 10 N. Miyaura, T. Yanagi and A. Suzuki, Synth. Commun., 1981,
Table 4, no signicant decrease in conversion was observed 11, 513.
aer performing at least 10 cycle experiments. ICP analysis 11 L. Wu, Z. Li, F. Zhang, Y. He and Q. Fan, Adv. Synth. Catal.,
detected that the weight loss of Pd aer 10 consecutive runs is 2008, 350, 846.
2.1%. A small amount of yield decline may be due to the loss of 12 K. Sawai, R. Tatumi, T. Nakahodo and H. Fujihara, Angew.
Pd nanoparticles in the recycling process. It is thus concluded Chem., Int. Ed., 2008, 47, 7023.
that the nature of Pd active sites did not change aer being used 13 V. Polshettiwar, A. Decottignies, C. Len and A. Fihri,
repetitively. The results further conrmed the high recyclability
of Pd–Fe–1(H).
Suzuki coupling reactions between 1-iodo-4-methyl-benzene
and phenylboronic acids in aqueous medium were used for
ChemSusChem, 2010, 3, 502.
14 V. I. Sokolov, E. G. Rakov, N. A. Bumagin and
M. G. Vinogradov, Fullerenes, Nanotubes, Carbon
Nanostruct., 2010, 18, 558–563.
template reaction. We conducted a series of experiments, the 15 A. Gniewek, J. J. Ziolkowski, A. M. Trzeciak, M. Zawadzki,
datum refer to Table 5. All the Pd–Fe catalysts displayed high H. Grabowska and J. Wrzyszcz, J. Catal., 2008, 254, 121–130.
catalytic activity and the yield could reach above 80% aer cycle 16 R. Najman, J. K. Cho, A. F. Coffey, J. W. Davies and
5 times. Especially when Pd : Fe ¼ 1 : 1, it could achieve a good M. Bradley, Chem. Commun., 2007, 5031–5033.
yield of 90% which was much better than others and the 17 S. Y. Liu, Q. Z. Zhou, Z. N. Jin, H. J. Jiang and X. Z. Jiang,
reduction of the yield was least. The above conclusions fully
Chin. J. Catal., 2010, 31, 557–561.
indicate that Pd–Fe–1(H) has optimal catalytic activity.
18 Z. Zheng, H. Li, T. Liu and R. Cao, J. Catal., 2010, 270, 268–
274.
19 D. D. Das and A. Sayari, J. Catal., 2007, 246, 60–65.
20 S. E. Garcia-Garrido, J. Francos, V. Cadierno, J. M. Basset and
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Conclusions
In summary, the present work reports composition controllable
and easily reusable Pd–Fe catalysts with hollow chamber 21 V. Polshettiwar and R. S. Varma, Tetrahedron, 2010, 66, 1091–
structure prepared through a vesicle-assisted chemical reduc-
1097.
tion method. The as-prepared hollow Pd–Fe catalyst exhibits 22 Y. Li, P. Zhou, Z. Dai, Z. Hu, P. Sun and J. C. Bao, New J.
much high activity during Suzuki cross-coupling reactions in Chem., 2006, 30, 832.
water by increasing the number of Pd active sites. Other hollow 23 P. Zhou, Y. Li, P. Sun, J. Zhou and J. C. Bao, Chem. Commun.,
bimetallic catalysts could also be prepared based on the present 2007, 1418.
method, offering more opportunities in designing new and 24 G. Chen, D. Xia, Z. Nie, Z. Wang, L. Wang, L. Zhang and
powerful catalysts.
J. Zhang, Chem. Mater., 2007, 19, 1840.
25 X. Chen, W. Yang, S. Wang, M. Qiao, S. Yan, K. Fan and
H. He, New J. Chem., 2005, 29, 266.
26 H. Li, D. Q. Zhang, G. S. Li, Y. Xu, Y. F. Lu and H. X. Li, Chem.
Commun., 2010, 46, 791.
Acknowledgements
The authors are grateful to the Key Laboratory of Nonferrous
Metals Chemistry and Resources Utilization, Gansu Province, 27 Y. Sun, B. Mayers and Y. Xia, Adv. Mater., 2003, 15, 641.
for nancial support. Additionally, we are also very grateful for 28 Y. Song, R. M. Garcia, R. M. Dorin, H. Wang, Y. Qiu and
the Scholarship Award for Excellent Doctoral Student granted
J. A. Shelnutt, Angew. Chem., Int. Ed., 2006, 45, 8126.
by Lanzhou University. The authors are grateful to Dr R. Q. 29 H. Xu and W. Wang, Angew. Chem., Int. Ed., 2007, 46, 1489.
Wang for correction of the manuscript.
30 H. Li, Z. H. Zhu, J. Liu, S. H. Xie and H. X. Li, J. Mater. Chem.,
2010, 20, 4366.
31 H. Li, J. Liu, S. H. Xie, M. H. Qiao, W. L. Dai, Y. F. Lu and
H. X. Li, Adv. Funct. Mater., 2008, 18, 3235.
Notes and references
1 N. Miyaura, K. Yamada and A. Suzuki, Tetrahedron Lett., 32 H. P. Liang, H. M. Zhang, J. S. Hu, Y. G. Guo, L. J. Wan and
1979, 20, 3437.
C. L. Bai, Angew. Chem., Int. Ed., 2004, 43, 1540.
2 A. Molnar, Chem. Rev., 2011, 111, 2251.
33 X. Zhang and D. Li, Angew. Chem., Int. Ed., 2006, 45, 5971.
3 V. Polshettiwar, A. Decottignies, C. Len and A. Fihri, 34 Y. Sun, B. Bayers and Y. Xia, Adv. Mater., 2003, 15, 641.
ChemSusChem, 2010, 3, 502.
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