Journal of the American Chemical Society
Page 4 of 6
the parent framework can be recovered (Figure 3a). To prove that not
ence, Office of Basic Energy Sciences, of the U.S. Department of Ener-
gy under Contract No. DE-AC02-05CH11231.
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only the COF remains intact but that the BF3 species also retain their
catalytic activity, BF3⊂COF-701 was tested in a benchmark Lewis acid
catalyzed Diels-Alder cycloaddition reaction.18 The acceleration over
the non-catalyzed reaction was quantified by recording the increase in
yield at a fixed reaction time (8 h). It was found that the immobilized
BF3 species remained active and retained 86% of the activity of free
BF3·OEt2 (Table 1). After isolation from the reaction media and re-
moval of the guest elements, confirmed by Inductively Coupled Plasma
– Optical Emission Spectroscopy (ICP-OES) and SEM Energy-
Dispersive X-ray Spectroscopy (EDS), the solid residue displayed a
WAXS pattern and FT-IR spectrum identical to that of parent COF-
701 (Supplementary Section S11 and Figure 3b). These experiments
prove that BF3 species can be immobilized in COF-701 and retain their
Lewis acidity.
REFERENCES
(1) Côté, A. P.; Benin, A. I.; Ockwig, N. W.; O’Keeffe, M.; Matzger, A. J.;
Yaghi, O. M. Porous, Crystalline, Covalent Organic Frameworks. Science 2005,
310, 1166–1170.
(2) El-Kaderi, H. M.; Hunt, J. R.; Mendoza-Cortés, J. L.; Côté, A. P.; Taylor,
R. E.; O’Keeffe, M.; Yaghi, O. M. Designed Synthesis of 3D Covalent Organic
Frameworks. Science 2007, 316, 268–272.
(3) Diercks, C. S.; Yaghi, O. M. The Atom, the Molecule, and the Covalent
Organic Framework. Science 2017, 355, eaal1585.
(4) Ding, S. Y.; Wang, W. Covalent Organic Frameworks (COFs): From
Design to Applications. Chem. Soc. Rev. 2013, 42, 548–568.
(5) Waller, P. J.; Lyle, S. J.; Osborn Popp, T. M.; Diercks, C. S.; Reimer, J. A.;
Yaghi, O. M. Chemical Conversion of Linkages in Covalent Organic
Frameworks. J. Am. Chem. Soc. 2016, 138, 15519–15522.
(6) Uribe-Romo, F. J.; Hunt, J. R.; Furukawa, H.; Klöck, C.; O’Keeffe, M.;
Yaghi, O. M. A Crystalline Imine-Linked 3-D Porous Covalent Organic
Framework. J. Am. Chem. Soc. 2009, 131, 4570–4571.
(7) Uribe-Romo, F. J.; Doonan, C. J.; Furukawa, H.; Oisaki, K.; Yaghi, O. M.
Crystalline Covalent Organic Frameworks with Hydrazone Linkages. J. Am.
Chem. Soc. 2011, 133, 11478–11481.
(8) Kuhn, P.; Antonietti, M.; Thomas, A. Porous, Covalent Triazine-Based
Frameworks Prepared by Ionothermal Synthesis. Angew. Chem., Int. Ed. 2008,
47, 3450–3453.
(9) Guo, J.; Xu, Y.; Jin, S.; Chen, L.; Kaji, T.; Honsho, Y.; Addicoat, M. A.;
Kim, J.; Saeki, A.; Ihee, H.; Seki, S.; Irle, S.; Hiramoto, M.; Gao, J.; Jiang, D.
Conjugated Organic Framework with Three-Dimensionally Ordered Stable
Structure and Delocalized π Clouds. Nat. Commun. 2013, 4, 2736.
(10) Pyles, D. A.; Crowe, J. W.; Baldwin, L. A.; McGrier, P. L. Synthesis of
Benzobisoxazole-Linked Two-Dimensional Covalent Organic Frameworks and
Their Carbon Dioxide Capture Properties. ACS Macro Lett. 2016, 5, 1055–
1058.
(11) Wei, P.-F.; Qi, M.-Z.; Wang, Z.-P.; Ding, S.-Y.; Yu, W.; Liu, Q.; Wang, L.-
K.; Wang, H.-Z.; An, W.-K.; Wang, W. Benzoxazole-Linked Ultrastable
Covalent Organic Frameworks for Photocatalysis. J. Am. Chem. Soc. 2018, 140,
4623–4631.
(12) Zhang, B.; Wei, M.; Mao, H.; Pei, X.; Alshmimri, S. A.; Reimer, J. A.;
Yaghi, O. M. Crystalline Dioxin-Linked Covalent Organic Frameworks from
Irreversible Reactions. J. Am. Chem. Soc. 2018, 140, 12715–12719.
(13) Knoevenagel, E. Condensation von Malonsäure Mit Aromatischen
Aldehyden Durch Ammoniak Und Amine. Ber. Dtsch. Chem. Ges. 1898, 31,
2596–2619.
(14) Zhuang, X.; Zhao, W.; Zhang, F.; Cao, Y.; Liu, F.; Bi, S.; Feng, X. A Two-
Dimensional Conjugated Polymer Framework with Fully sp2-Bonded Carbon
Skeleton. Polym. Chem. 2016, 7, 4176–4181.
(15) Jin, E.; Asada, M.; Xu, Q.; Dalapati, S.; Addicoat, M. A.; Brady, M. A.;
Xu, H.; Nakamura, T.; Heine, T.; Chen, Q.; Jiang, D. Two-Dimensional sp2
Carbon–Conjugated Covalent Organic Frameworks. Science 2017, 357, 673–
676.
(16) Jin, E.; Li, J.; Geng, K.; Jiang, Q.; Xu, H.; Xu, Q.; Jiang, D. Designed
Synthesis of Stable Light-Emitting Two-Dimensional sp2 Carbon-Conjugated
Covalent Organic Frameworks. Nat. Commun. 2018, 9, 4143.
(17) Xu, S.; Wang, G.; Biswal, B. P.; Addicoat, M.; Paasch, S.; Sheng, W.;
Zhuang, X.; Brunner, E.; Heine, T.; Berger, R.; Feng, X. A Nitrogen-Rich 2D
sp2-Carbon-Linked Conjugated Polymer Framework as a High-Performance
Cathode for Lithium-Ion Batteries. Angew. Chem., Int. Ed. 2019, 58, 849–853.
(18) Zhao, Y.; Liu, H.; Wu, C.; Zhang, Z.; Pan, Q.; Hu, F.; Wang, R.; Li, P.;
Huang, X.; Li, Z. Fully sp2-Carbon Conjugated Two-Dimensional Covalent
Organic Frameworks as Artificial Photosystem I with Unprecedented Efficiency.
Angew. Chem., Int. Ed. 2019, 58, 5376–5381.
(19) Cui, Y. .; Fang, Q.; Lei, H.; Xue, G.; Yu, W. . Syntheses, Structures and
Second-Order Nonlinear Optical Properties of Octupolar Compounds: 2,4,6-
Tri-Substituted s-Triazine. Chem. Phys. Lett. 2003, 377, 507–511.
(20) Ji, P.; Drake, T.; Murakami, A.; Oliveres, P.; Skone, J. H.; Lin, W. Tuning
Lewis Acidity of Metal-Organic Frameworks via Perfluorination of Bridging
Ligands: Spectroscopic, Theoretical, and Catalytic Studies. J. Am. Chem. Soc.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
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57
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In conclusion, we developed a new strategy to synthesize porous,
crystalline olefin-linked COFs, exemplified by the layered hcb topolo-
gy COF-701. The framework exhibits high compositional purity, po-
rosity, and crystallinity as confirmed by spectroscopic, sorption, and
scattering techniques. Due to the chemical nature of the olefin linkages,
COF-701 was found to retain its crystallinity and chemical composi-
tion in the presence of concentrated Brønsted acids and bases, organo-
lithium reagents, and Lewis acids. The utility of this pronounced chem-
ical stability was exploited for the immobilization of a strong Lewis acid
catalyst within the pores of the material. The activity of the COF cata-
lyst was confirmed by a benchmark Lewis acid catalyzed Diels-Alder
reaction. We anticipate that olefin-linked COFs, as exemplified by
COF-701, will serve as a robust, functionalizable platform for a broad
array of chemical transformations.
ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the ACS
Publications website.
General experimental methods, supplementary spectra and analy-
sis details (PDF)
AUTHOR INFORMATION
Corresponding Author
* yaghi@berkeley.edu
ORCID
Hao Lyu: 0000-0001-7393-2456
Christian S. Diercks: 0000-0002-7813-0302
Chenhui Zhu: 0000-0003-1263-5065
Omar M. Yaghi: 0000-0002-5611-3325
Notes
The authors declare no competing financial interests.
ACKNOWLEDGMENT
Aspects of the research on COFs is part of an ongoing collaboration
with King Abdulaziz City for Science and Technology (Center of Ex-
cellence for Nanomaterials and Clean Energy Applications). The au-
thors thank Dr. Yuzhong Liu, Dr. Haiyan Mao, Mr. Mengyu Gao, Ms.
Xiaokun Pei, Mr. Nikita Hanikel, Dr. Nobumichi Tamura, Mr. Wentao
Xu, Dr. Mathieu Prévot, Mr. Khetpakorn Chakarawet, Prof. Sultan A.
Alshmimri, Prof. Saeed M. Alshihri, and Prof. Jeffrey A. Reimer for
their help with characterization and helpful discussion. The Advanced
Light Source and NCEM are supported by the Director, Office of Sci-
ACS Paragon Plus Environment