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ChemComm
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COMMUNICATION
Journal Name
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,2,6,6,-tetramethylpiperidinyloxyl (TEMPO) as active oxygen
•
−
6022.
DOI: 10.1039/C9CC07661A
trapping agent, the characteristic signals of DMPO-O
2
and
D. Stewart, D. Antypov, M. S. Dyer, M. J. Pitcher, A. P.
Katsoulidis, P. A. Chater, F. Blanc, M. J. Rosseinsky, Nat.
1
TEMPO- O
2
were observed in the resulting EPR spectra, which
•
−
and 1
reavealed that O
2
O involved in the photoxidative
2
Commun., 2017, 8, 1102−1111.
coupling of amines. Simultaneously, benzylamine is oxidized by
photogenerated holes to transform into benzylamine radical
cation. The reaction of the radical cation with active oxygen
species to generate an hydroperoxy (phenyl)methylamine
intermediate, which could convert into benzylimine after
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4
5
H. Furukawa, O. M. Yaghi, J. Am. Chem. Soc., 2009, 131
875–8883.
,
8
Q. Gao, X. Li, G. Ning, K. Leng, B. Tian, C. Liu, W. Tang, H. Xub,
K. Loh, Chem. Commun., 2018, 54, 2349–2352.
X. Ding, J. Guo, X. Feng, Y. Honsho, J. Guo, S. Seki, P.
Maitarad, A. Saeki, S. Nagase, D. Jiang, Angew. Chem. Int.
Ed., 2011, 50, 1289–1293.
2 2 2 2
elimination of H O . The generated H O could act as an
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1
1
C. R. DeBlase, K. E. Silberstein, T. T. Truong, H. D. Abruna, W.
R. Dichtel, J. Am. Chem. Soc., 2013, 135, 16821–16824.
additional oxidant, and further oxidize benzylamine to produce
benzylimine. Finally, the addition reaction between
benzylimine intermediate and an additional benzylamine
results in the desired imine product after remove of ammonia.
In another path, the generated benzylimine might be
hydrolyzed to benzaldehyde, which further condense with a
benzylamine to form the coupling imine. Interestingly, in the
oxidation of 4–methoxylbenzylamine substrate, a mixture of
the corresponding benzaldehyde and amide was produced,
suggesting that oxidative dehydrogenation of the benzylimine
T. He, K. Geng, D. Jiang, ACS Materials Lett., 2019,
03−208.
1,
2
L. Chen, K. Furukawa, J. Gao, A. Nagai, T. Nakamura, Y. Dong
and D. Jiang, J. Am. Chem. Soc., 2014, 136, 9806–9809.
V. S. Vyas, F. Haase, L. Stegbauer, G. Savasci, F. Podjaski, C.
Ochsenfeld, B. V. Lotsch, Nat Commun, 2015, 6, 8508–8517.
0 W. Liu, Q. Su, P. Ju, B. Guo, H. Zhou, G. Li, Q. Wu,
chemSusChem, 2017, 10, 664–669.
1 L. Stegbauer, K. Schwinghammer, B. V. Lotsch, Chem. Sci.,
2014, 5, 2789–2793.
2 Y. F. Zhi, Z. P. Li, X. Feng, H. Xia, Y. M. Zhang, Z. Shi, Y. Mu, X.
intermediate led to a nitrile, followed by hydrolysis to give the
resulting amide.28
The cycling test of photocatalytic oxidative coupling of
amines was performed to further demonstrate the stability
11, 4916−4922.
and reusability of TFPT-BMTH catalyst. As shown in Fig. S25, 14 X. Wu, L. Gagliardi, D. G. Truhlar, J. Am. Chem. Soc.,
2
018, 140, 7904–7912.
ESI†, the conversions in five repeating cycles were over 97%,
indicating the significant reusability of TFPT-BMTH. After
recycling reactions, the characterization results by PXRD,
FT−IR, SEM and TEM (Fig. S26-S29, ESI†) also showed that the
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5 R. Chen, J.-L. Shi, Y. Ma, G. Lin, X. Lang, C. Wang, Angew.
Chem. Int. Ed., 2019, 58, 6430–6434.
6 S. Yao, S. Saaby, R. G. Hazell, K. A. Jørgensen, Chem.-Eur. J.,
2
000, 6, 2435–2448.
recovered samples retained its original structure and 17 F. J. Uribe-Romo, C. J. Doonan, H. Furukawa, K. Oisaki, O. M.
Yaghi, J. Am. Chem. Soc., 2011, 133, 11478–11481.
8 K. S. W. Sing, D. H. Everett, R. A. W. Haul, L. Moscou, R. A.
Pierotti, J. Rouquerol, T. Siemieniewska, Pure & Appl.
Chem.,1985, 57, 603–619.
morphology. The obtained results demonstrated that TFPT-
BMTH could be used as excellent heterogeneous catalyst with
photocatalytic stability.
In summary, we have designed and synthesized a
hydrophilic hydrazone–based COF TFPT-BMTH with high-
degree integration of 2-methoxyethoxy groups on the channel
walls. The hydrophilic COF material has further been empolyed
as heterogeneous photocatalyst for oxidative coupling of
benzylamines to imines, and the results have also
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9 A. K. Sekizkardes, S. Altarawneh, Z. Kahveci, T. İslamoğlu, H.
M. El-Kaderi, Macromolecules., 2014, 47, 8328–8334.
0 P. Yang, R. Wang, M. Zhou, X. Wang, Angew. Chem. Int. Ed.,
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018, 57, 8674–8677.
1 H. Wang, X. Sun, D. Li, X. Zhang, S. Chen, W. Shao, Y. Tian, Y.
Xie, J. Am. Chem. Soc., 2017, 139, 2468–2473.
2 E. L. Spitler, W. R. Dichtel, Nat. Chem., 2010, 2, 672–677.
demonstrated
superior
photocatalytic
activity
and 23 Z. Li, N. Huang, K. H. Lee, Y. Feng, S. Tao, Q. Jiang, Y. Nagao,
S. Irle, D. Jiang, J. Am. Chem. Soc., 2018, 140, 12374−12377.
4 J. Zhang, M. Zhang, R.-Q. Sun, X. Wang, Angew. Chem. Int.
Ed., 2012, 51, 10145–10149.
environmentally friendly process under ambient conditions. In
addition, the TFPT-BMTH has shown good recyclability
without any substantial loss of catalytic activity. Our current
protocol provides a convenient strategy to develop COFs
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5 L. Lin, Z. Yu, X. Wang, Angew. Chem. Int. Ed., 2019, 58
164–6175.
,
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material with high crystallinity and designed functionalities, 26 N. Zhang, X. Li, H. Ye, S. Chen, H. Ju, D. Liu, Y. Lin, W. Ye, C.
Wang, Q. Xu, J. Zhu, L. Song, J. Jiang, Y. Xiong, J. Am. Chem.
Soc., 2016, 138, 8928–8935.
which show potential to achieve the efficient and
environmentally benign photocatalytic transformations.
The authors gratefully acknowledge financial support from
the National Natural Science Foundation of China (51703076).
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7 Z. J. Wang, S. Ghasimi, K. Landfester, K. A. Zhang, Adv.
Mater., 2015, 27, 6265–6270.
8 J. W. Kim, K. Yamaguchi, N. Mizuno, Angew. Chem. Int. Ed.,
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008, 47, 9249 –9251.
Conflicts of interest
There are no conflicts to declare.
Notes and references
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| J. Name., 2012, 00, 1-3
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