Application of Electron-Rich Covalent Organic Frameworks COF-JLU25 for Photocatalytic Aerobic Oxidative Hydroxylation of Arylboronic Acids to Phenols

Article abstract of DOI:10.1002/ejoc.202100173

Visible-light-driven organic reactions are environmentally friendly green chemical transformations among which photosynthetic oxidative hydroxylation of arylboronic acids to phenols has attracted increasing research interest during the very recent years. Given the efficiency and reusability of heterogeneous catalysts, COF-JLU25, an electron-rich COF-based photocatalyst constructed by integrating electron-donating blocks 1,3,6,8-tetrakis(4-aminophenyl)pyrene (PyTA) and 4-[4-(4-formylmethyl)-2,5-dimethoxyphenyl] benzaldehyde (TpDA), was selected as a photocatalyst for the oxidative hydroxylation of arylboronic acids. In our studies, COF-JLU25 demonstrated excellent photocatalytic activity with high efficiency, robust reusability, and low catalyst loading, showcasing an application potential of previously underexplored COF-based photocatalyst composed solely of electron-rich units.

Full text of DOI:10.1002/ejoc.202100173

Full Papers
doi.org/10.1002/ejoc.202100173
Very Important Paper
1
2
Application of Electron-Rich Covalent Organic Frameworks
COF-JLU25 for Photocatalytic Aerobic Oxidative
Hydroxylation of Arylboronic Acids to Phenols
3
4
5
6
7
8
9
Guangjun Xiao+,[a, b, c] Wenqian Li+,[a, b] Tao Chen,[a, b] Wei-Bo Hu,[a, b] Hui Yang,[a, b, c]
Yahu A. Liu,[d] and Ke Wen*[a, b, c]
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
56
57
Visible-light-driven organic reactions are environmentally
friendly green chemical transformations among which photo-
synthetic oxidative hydroxylation of arylboronic acids to
phenols has attracted increasing research interest during the
very recent years. Given the efficiency and reusability of
heterogeneous catalysts, COF-JLU25, an electron-rich COF-
based photocatalyst constructed by integrating electron-donat-
ing blocks 1,3,6,8-tetrakis(4-aminophenyl)pyrene (PyTA) and 4-
[4-(4-formylmethyl)-2,5-dimethoxyphenyl]
benzaldehyde
(TpDA), was selected as a photocatalyst for the oxidative
hydroxylation of arylboronic acids. In our studies, COF-JLU25
demonstrated excellent photocatalytic activity with high effi-
ciency, robust reusability, and low catalyst loading, showcasing
an application potential of previously underexplored COF-based
photocatalyst composed solely of electron-rich units.
Introduction
gated frameworks, and π-π stacking columns.[9] When COF-
based catalysts specially designed for oxidative hydroxylation
reactions were irradiated under visible light, the electron
generated could be transferred to O2, forming superoxide
Visible-light-driven organic reactions are environmentally
friendly alternatives to chemical transformations.[1] Since phe-
nols are important intermediates widely found in natural
products and pharmaceutical drug candidates, recent years
have seen increasing attention to mild and efficient photo-
synthetic methods for hydroxylation of arylboronic acids to
phenols.[2] In order to enhance catalytic activities, various
porous organic-based photocatalysts (POPs)[3] have been de-
signed, including covalent organic frameworks (COFs),[2c,4]
metal-organic frameworks (MOFs),[2g,i] porous coordination poly-
mers (PCPs),[5] conjugated microporous polymers (CMPs),[6] and
hyper-crosslinked polymers (HCPs).[7] Among those photocata-
lysts, COFs are especially fascinating owing to properties such
as large surface area, structural versatility, easy post-synthetic
modification, and high chemical stability.[8] Furthermore, COF-
based photocatalysts display longer-wavelength absorption,
good fluorescence properties, and efficient charge transmission,
originated from their tunable band gaps, extended π-conju-
*
*
À [2b,c]
À
radical anion O2
.
As O2 is a critical active propellant to
drive the oxidative hydroxylation of arylboronic acids to
phenols, the catalytic performance should be able to be
improved by sufficient electrons generated by photocatalysts
and smooth transfer of the electrons from COFs to O2. In
searching for such electron-rich COFs, our attention was
attracted by the recently reported COF-JLU25 (Scheme 1) owing
to its catalytic activity in the C-3 formylation reaction of N-
methylindole.[10] Application of electron-deficient COFs and
donor–acceptor COFs as photocatalysts has been well
documented,[2b,c,k] but COF-based photocatalysts comprised
solely of electron-donating units have not been commonly
seen. Given that COF-JLU25 was constructed from two electron-
donating units, 1,3,6,8-tetrakis(4-aminophenyl)pyrene (PyTA)
and 4-[4-(4-formylmethyl)-2,5-dimethoxyphenyl] benzaldehyde
(TpDA), we envisioned that the electron-rich units in such an
eclipsed stacking structure might be a source for abundant
electrons to facilitate oxidative reactions. Therefore, we ex-
plored the application of COF-JLU25 in photocatalytic aerobic
oxidative hydroxylation of arylboronic acids to phenols.
[a] G. Xiao,+ W. Li,+ T. Chen, W.-B. Hu, Prof. Dr. H. Yang, Prof. Dr. K. Wen
Shanghai Advanced Research Institute, Chinese Academy of Sciences
Shanghai 201210, P. R. China
E-mail: wenk@sari.ac.cn
[b] G. Xiao,+ W. Li,+ T. Chen, W.-B. Hu, Prof. Dr. H. Yang, Prof. Dr. K. Wen
University of Chinese Academy of Sciences
Beijing 100049, P.R. China
Results and Discussion
[c] G. Xiao,+ Prof. Dr. H. Yang, Prof. Dr. K. Wen
School of Physical Science and Technology,
ShanghaiTech University
The COF-JLU25 synthesized by following a reported procedure
(Scheme 1) was characterized by Fourier transform infrared (FT-
IR) spectroscopy, solid-state 13C cross-polarization magic angle
spinning (13C CP-MAS) NMR spectroscopy, powder X-ray
diffraction (PXRD) analysis, scanning electron microscopy (SEM),
transmission electron microscopy (TEM), Brunauer–Emmett–
Teller (BET) surface area measurements, elemental analysis (EA)
Shanghai 201210, P. R. China
[d] Dr. Y. A. Liu
Medicinal Chemistry, ChemBridge Research Laboratories,
San Diego CA 92127, USA
[+] Authors contributed equally to this work.
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/ejoc.202100173
Eur. J. Org. Chem. 2021, 1–7
1
© 2021 Wiley-VCH GmbH
��
These are not the final page numbers!

Full Papers
doi.org/10.1002/ejoc.202100173
°
and thermal gravimetric analysis (TGA). Fourier transform infra-
red (FTIR) spectrum of COF-JLU25 showed a typical stretching
band of C=N at 1621 cmÀ 1 for COF-JLU25, but not for PyTA or
TpDA, while the -HC=O band in TpDA (1691 cmÀ 1) and NÀ H2
band in PyTA (3500~3300 cmÀ 1) were almost completely
disappeared in COF-JLU25 (Figure S1), implying Shiff base
formation from aldehyde and amino functionalities. The peak at
157 ppm in 13C CP-MAS NMR was also consistent with carbons
of aldimines (Figure 1a).
COF-JLU25 sample exhibited two intense XRD peaks at 2.70
1
2
3
4
5
6
7
8
9
°
and 5.39 which were assignable to (100) and (200) facets,
°
°
respectively. Besides, three other peaks at 3.93 (110), 8.09
°
(300), and 10.80 (040) were also shown in the experimental
PXRD pattern. The simulated PXRD patterns of an eclipsed AA
stacking model could reproduce the PXRD results in terms of
the peak position and intensity (Rwp of 4.87% and Rp of 3.35%).
The unit cell was created with a P1 space group, and the Pawley
refinement afforded cell parameters of a=b=32.80 Å, c=
°
°
The crystalline structure of the COFs was confirmed by
powder X-ray diffraction (PXRD) measurement (Figure 1b). The
3.82 Å, and α=β=90.00 and γ=95.01 (Figure S7 and S8). The
SEM images of COF-JLU25 showed a root-like surface morphol-
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
56
57
Scheme 1. (a) Synthesis of COF-JLU25. (b) The structural model of COF-JLU25.
Figure 1. (a) Solid-state 13C CP-MAS NMR spectrum of COF-JLU25. (b) PXRD patterns of COF-JLU25. (c) TEM image of COF-JLU25 (scale bar=50 nm). (d) N2
adsorption isotherms of activated COF-JLU25 at 77 K. Insert: the derived pore size distribution.
Eur. J. Org. Chem. 2021, 1–7
www.eurjoc.org
2
© 2021 Wiley-VCH GmbH
��
These are not the final page numbers!

Full Papers
doi.org/10.1002/ejoc.202100173
ogy (Figure S2), while the TEM images revealed that COF-JLU25
white light emitting diodes (LED) for 9 days, and in various
organic solvents (Figure S6).
1
2
3
4
5
6
7
8
9
has a stacked structure: clear lattice stripes corresponding to
the ordered nanochannel (Figure 1c, Figure S3). Nitrogen
adsorption-desorption experiments at 77 K featured a type-IV
reversible isotherm which is characteristic for microporous
structures (Figure 1d). The pore size distribution calculated by
the nonlocal density functional (NLDFT) method suggested a
narrow pore size distribution centered at 2.3 nm, which agreed
well with the predicted pore diameter (2.5 nm) for eclipsed (AA)
stacking geometries of the frameworks (Scheme S1). The value
of the BET surface area in our case was measured to be
141.31 m2 gÀ 1, smaller than the previously reported COF-
JLU25.[10] Usually, the difference in BET areas could be attributed
to the different extent of structural twists and overlaps in COFs
prepared under non-identical conditions. Another possible
cause of a smaller BET surface area of COF-JLU25 obtained in
our hands might be caused by unreacted monomers or
oligomers trapped in the pores. TGA analysis indicated that
Photoelectric Properties. The optical and photoelectric
properties of COF-JLU25 were studied using ultraviolet-visible
diffuse reflectance spectroscopy (UV-vis DRS), photolumines-
cence (PL) spectroscopy, time-resolved photoluminescence
(TRPL) spectroscopy, and ultraviolet photoelectron spectroscopy
(UPS). The UV-Vis DRS of COF-JLU25 showed abroad absorption
in the region from UV to visible regions (200–465 nm) (Fig-
ure 2a) and the PL spectrum showed a maximum emission
intensity at 540 nm (Figure 2b). The TRPL spectrum revealed the
PL decay kinetics from which the average lifetime excited at
360 nm was estimated to be 1.2 ns (Figure 2c). The optical band
gap (Eg) of COF-JLU25 calculated by Kubelka-Munk function
was 2.22 eV (Figure 2a). The energy of the valence band
maximum (EVB =À 5.77 eV) of the COFs relative to the vacuum
level was obtained by subtracting the UPS width from the
excitation energy (He I, 21.2 eV) (Figure 2d). Thus, the approx-
imate conduction band potentials (ECB) were calculated to be
À 3.55 eV, which was obviously higher than the potential of O2/
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
56
57
°
COF-JLU25 retained more than 98% of its initial mass till 420 C,
and then started to decompose, with 72% of initial mass left as
*
À
°
the temperature reached 800 C (Figure S4). Besides, the
O2 (À 4.16 eV) (Figure S9), allowing reduction of molecular O2
*
structure of COF-JLU25 was retained after soaking in boiling
water, NaHCO3 (2 M), TFA, or NaOH (9 M) for 3 days (Figure S5).
In addition, COF-JLU25 was stable under irradiation by a 20 W
to O2 À under appropriate light.
Photocatalysis Activity. In our initial exploration of aerobic
hydroxylation of arylboronic acids to assess its photocatalytic
activity of COF-JLU25, 4-(methoxycarbonyl) phenylboronic acid
Figure 2. (a) UV-vis diffuse reflectance spectrum of COF-JLU25. Inset: Band gaps determined by the Kubelka-Munk-transformed reflectance spectrum. (b) PL
spectrum of COF-JLU25 (excitation at 360 nm). Insert: appearance of COF-JLU25. (c) TLPL spectrum of COF-JLU25 (excitation at 360 nm). (d) High-resolution
valence band UPS of COF-JLU25.
Eur. J. Org. Chem. 2021, 1–7
www.eurjoc.org
3
© 2021 Wiley-VCH GmbH
��
These are not the final page numbers!

Full Papers
doi.org/10.1002/ejoc.202100173
(1) was chosen as the substrate and i-Pr2NEt as the sacrificial
sacrificial agent (Table 1, entries 2–4). The conversion 1a could
reach nearly 100% (Table 1, entry 5). On the contrary, when
monomer (TpDA and PyTA) were used to replace COF-JLU25,
no product was detected (Table 1, entries 6 and 7). In addition,
we also performed a kinetic study by monitoring the time-
dependent conversions using NMR analysis (Figure 3).
1
2
3
4
5
6
7
8
9
agent. The transformation of boronic acid 1a to 4-(meth-
oxycarbonyl) phenol (2a) was carried out in a mixed solvent of
CH3CN/D2O under irradiation with a 20 W white light emitting
diode (LED). As shown in Table 1, the reaction did not result in
the desired product 2a in the absence of COF-JLU25 (Table 1,
entry 1). The transformation could not occur when the reaction
was conducted in the dark, under N2 atmosphere, or without a
With the optimized reaction conditions, we explored the
scope of arylboronic acid derivatives as substrates. We were
delighted to find that the photocatalytic aerobic oxidative
hydroxylation tolerated substrates with a broad variety of
functional groups, such as ester, aldehyde, nitro, cyano, alkyl,
and halide groups (Table 2 and Figure 3). Generally, phenyl-
boronic acids with electron-withdrawing groups or heteroar-
omatic boronic acid (i.e. pyridinyl boronic acid) could be
effectively converted into the corresponding phenols in high
conversions (>90%, Table 2, entries 1–6) within 24 h. Larger
conjugated π-electron systems showed good conversions
(Table 2, entries 7 and 8). However, phenylboronic acids with no
substituent (Table 2, entry 9), weak electron-donating substitu-
ent (Table 2, entry 10), or weak electron-withdrawing substitu-
ents (Table 2, entries 11–13) required prolonged reaction time
to get a satisfactory conversion. This could be attributed to the
reason that a boron atom connected to an electron-deficient
conjugated π-electron system has a greater tendency to accept
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
56
57
Table 1. Control experiments for oxidative hydroxylation of 1a.[a]
Entry
Photocatalyst
Visible light
Air
DIEA
Conversion [%][b]
1
2
3
4
5
6
7
–
+
–
+
+
+
+
+
+
+
–
+
+
+
+
+
+
+
–
+
+
+
nd.[c]
nd.[c]
nd.[c]
trace
>99
nd.[c]
nd.[c]
COF-JLU25
COF-JLU25
COF-JLU25
COF-JLU25
TpDA
PyTA
[a] Reaction conditions: 1a (0.2 mmol), COF-JLU25 (5.0 mg), and i-Pr2NEt
(1.0 mmol) in CH3CN/D2O (3.0 mL, 4:1, v/v) under air and under irradiation
of 20 W white LEDs for 20 h. [b] Determined by 1H NMR of the crude
mixture. [c] Not detected.
*
À
an electron from O2 than a boron atom linked to an electron-
rich aromatic ring.
This photocatalyst could be easily separated from the
reaction solution by centrifugation and directly used in the next
catalytic run without any extra treatment or reactivation. In the
reusability test, the conversion rate of this photocatalyst was
not significantly reduced for seven successive cycles of reuse, as
evidenced by NMR analysis (Figure S10 and S11). The crystal-
Table 2. Substrate scope of COF-JLU25-catalyzed oxidative hydroxylation
of 1 to 2[a]
Entry
1
Ar-
Time [h]
Conversion [%][b]
1
2
3
4
5
6
7
8
1a
1b
1c
1d
1e
1f
1g
1h
1i
1j
1k
1l
1m
1n
4-CH3O2CC6H4
4-NO2C6H4
4-CHOC6H4
3-CHOC6H4
4-NCC6H4
12
24/56
18
12
18
16
18
24
24/72
24/72
24/72
24/72
24/72
96
99
90/99
99
99
99
99
99
91
35/99
25/99
43/99
40/99
38/99
trace
pyridine-4-yl
4-C6H5COC6H4
quinolin-6-yl
[c]
9
C6H5
[c]
10
11
12
13
14
4-CH3C6H4
[c]
4-BrC6H4
[c]
4-ClC6H4
4-FC6H4
[c]
[c]
4-CH3OC6H4
[a] Reaction conditions: 1 (0.2 mmol), COF-JLU25 (5.0 mg), and i-Pr2NEt
(1.0 mmol) in CH3CN/D2O (3.0 mL, 4:1, v/v) under air and under irradiation
of 20 W white LEDs. [b] Determined by 1H NMR of the crude mixture. [c]
DIEA (2.5 equiv.) was added at 24 h and 48 h.
Figure 3. (a) The time-dependent conversions of 1a, 1c, 1e–1h within 24 h.
(b) The time-dependent conversions of 1i–1m within 72 h.
Eur. J. Org. Chem. 2021, 1–7
www.eurjoc.org
4
© 2021 Wiley-VCH GmbH
��
These are not the final page numbers!

Full Papers
doi.org/10.1002/ejoc.202100173
linity of COF-JLU25 was well preserved even after seven cycles,
as shown by the PXRD analysis (Figure S12).
The transformation catalyzed by COF-JLU25 features low
catalyst loading, high efficiency, robust reusability, and compa-
tiability with substrates bearing a broad variety of functional
1
2
3
4
5
6
7
8
9
The excellent photocatalytic activity, robust reusability, and
low catalyst loading made COF-JLU25, possibly other electron-
rich COFs, as candidates of photocatalysts for oxidative
hydroxylation of arylboronic acids. Nonetheless, it is not feasible
to make a direct comparison of catalytical activities among
COFs with different electronic structures, such as electron-
deficient, donor-acceptor, and electron-rich COFs, owing to
various combinations of diverse building units in three catego-
ries of COFs.
*
À
groups. Photogeneration of O2 was verified by EPR analysis,
supporting a plausible mechanism in which the reaction
*
À
cascade goes through a sequence of the capture of radical O2
*
and then H , rearrangement, and hydrolysis of borate to afford
phenol product. The described work demonstrated an applica-
tion potential of a previously underexplored COF-based photo-
catalyst composed exclusively of electron-rich units.
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
56
57
To gain preliminary insight into the mechanism of the
oxidative hydroxylation reaction, the generation of O2 was Experimental Section
verified by electron paramagnetic resonance (EPR) spectrum
*
À
Unless otherwise noted, all reagents commercially available were
used without further purification. 1H and 13C NMR spectra were
recorded on 400 MHz Bruker NEO NMR Spectrometer. Mass spectra
(ESI analysis) were recorded on an Esquire 6000 spectrometer (LC/
MS). The 13C Cross-Polarization Magic Angle Spinning (CP-MAS)
NMR spectra were obtained on a Bruker Avance-III HD 400 Hz Solid
NMR with 3.2 mm double-resonance MAS probe at 100.6 MHz and
a MAS frequency of 10 kHz. The Fourier-transformed infrared (FT-IR)
spectra were obtained on a PerkinElmer Spectrum Two spectrom-
eter equipped with an attenuated total reflection (ATR) setup. The
scanning electron microscope (SEM) was performed on a JSM-
7401F emission scanning electron microscope and the transmission
electron microscopy (TEM) on a JEOL JEM-2100 Plus transmission
electron microscope. Thermo Graic Analysis (TGA) was performed
on a Mettler-Toledo TGA/DSC 3+/1100 LF analyzer under N2, and
(Figure S13). In the presence of superoxide radical scavenger
5,5-dimethyl-1-pyrroline N-oxide (DMPO), a typical signal of the
*
adduct of DMPO and O2 À was detected by EPR spectrum of the
air-saturated reaction mixture after being irradiated by visible
*
light for over 60s. Based on the verified existence of O2 À , a
plausible photocatalytic mechanism was proposed.[2b,c] A photo-
*
À
generated electron reduces O2 to O2 which then attacks the
empty p-orbital of boron atom to form peroxide radical 3. One
electron is deprived from the sacrificing agent DIEA by the
photogenerated hole on the surface of the catalyst to form
radical cation 5. One hydrogen radical is transferred from 5 to 3
to result in unstable peroxide anion 7 which rearranges into
phenyl dihydrogen borate 8. The hydrolysis of borate 8
provides the final product phenol 2 (Figure 4).
°
°
°
the samples were heated from 90 C to 800 C at a rate of 10 C/
min. N2 adsorption/desorption isotherms were measured at 77 K on
Micromeritics ASAP 2020 M system. Specific surface areas were
determined with the BrunauerÀ EmmettÀ Teller (BET) method, and
pore size distributions were calculated by was estimated by
nonlocal density functional (NLDFT) method. Powder X-ray diffrac-
tion (PXRD) patterns were recorded on a Bruker D8 Advance
instrument with Cu Kα radiation (λ=1.5418 Å) in the 2θ range of
Conclusion
In conclusion, electron-rich COF-based photocatalyst, COF-
JLU25 was studied for its catalytical behavior in the aerobic
photocatalytic transformation of arylboronic acids to phenols.
°
1.5–30 . Electron Paramagnetic Resonance (EPR) spectra were
collected on a Bruker EPR A300 spectrometer. Elemental analysis
was carried out on an Elementar Vario MICRO cube Elemental
Analyzer. UV–vis diffuse reflectance spectra (UV–vis DRS) were
recorded at room temperature on a Shimadzu UV 3600 Spectropho-
tometer. Photoluminescence (PL) emission spectra and PL decay
spectra were obtained from an FLS980 spectrophotometer (Edin-
burgh Instruments, UK).
Procedure for photocatalytic oxidative hydroxylation of
arylboronic acids
To
a solution of arylboronic acid (0.20 mmol) and i-Pr2NEt
(1.0 mmol) in CH3CN/D2O (3.0 mL, 4:1, v/v) was added COF-JLU25
(5.0 mg) resulting in a mixture which was sonicated for 5 min,
°
stirred under air at 25 C under irradiation with a 20 W white LED.
At every designated time point, 400 μL the reaction mixture was
filtered to remove solid, diluted with CH3CN /D2O (600 μL, 4:1, v/v),
and subjected to 1H NMR analysis. As the reactions did not result in
identifiable amounts of other products, the conversion was
calculated by the following equation.
Where Integral and Integral were the peak intensities (integrals)
2
1
of aromatic CH2 of the phenol product 2 and the unreacted boronic
Figure 4. Proposed mechanism of the photocatalytic hydroxylation of
arylboronic acids in the presence of COF-JLU25.
Eur. J. Org. Chem. 2021, 1–7
www.eurjoc.org
5
© 2021 Wiley-VCH GmbH
��
These are not the final page numbers!

Full Papers
doi.org/10.1002/ejoc.202100173
acid 1 in the 1H NMR spectrum of the sample collected at a
designated time.
Int. Ed. 2012, 51, 784; k) X. Yan, H. Liu, Y. Li, W. Chen, T. Zhang, Z. Zhao,
G. Xing, L. Chen, Macromolecules 2019, 52, 7977.
[3] a) T. Zhang, G. Xing, W. Chen, L. Chen, Mater. Chem. Front. 2020, 4, 332;
b) T.-X. Wang, H.-P. Liang, D. A. Anito, X. Ding, B.-H. Han, J. Mater. Chem.
A 2020, 8, 7003.
1
2
3
4
5
6
7
8
9
[4] a) H. Liu, J. Tang, H. Liu, C. Li, H. Li, Y. Ren, Q. Yang, C. Li, Y. Ren, J. Chen,
J. Tang, ACS Appl. Mater. Interfaces. 2020, 12, 20354; b) S. Li, L. Li, Y. Li, L.
Dai, C. Liu, Y. Liu, J. Li, J. Lv, P. Li, B. Wang, ACS Catal. 2020, 10, 8717;
c) W. Hao, D. Chen, Y. Li, Z. Yang, G. Xing, J. Li, L. Chen, Chem. Mater.
2019, 31, 810; d) W. Chen, L. Wang, D. Mo, F. He, Z. Wen, X. Wu, H. Xu, L.
Chen, Angew. Chem. Int. Ed. 2020, 59, 16902; e) W. Li, X. Huang, T. Zeng,
Y. A. Liu, W.-B. Hu, H. Yang, Y.-B. Zhang, K. Wen, Angew. Chem. Int. Ed.
2020, 60, 1869.
[5] a) Z. Li, Z. Ye, L. Chen, J. Cui, J. Chen, ACS Appl. Nano Mater. 2020, 3,
10720; b) J.-Z. Cheng, Z.-R. Tan, Y.-Q. Xing, Z.-Q. Shen, Y.-J. Zhang, L.-L.
Liu, K. Yang, L. Chen, S.-Y. Liu, J. Mater. Chem. A 2021, 9, 5787.
[6] Y. Zhi, Z. Yao, W. Jiang, H. Xia, Z. Shi, Y. Mu, X. Liu, ACS Appl. Mater.
Interfaces. 2019, 11, 37578.
Acknowledgements
This study was financially supported by National Key Research
and Development Program of China (2017YFA0206500), National
Natural Science Foundation of China (21871281), Shanghai Sailing
Program (19YF1452900), and Science and Technology Commission
of Shanghai Municipality (18DZ1100403). We thank the NMR Core
Facility, Analytical Instrumentation Center of SPST, ShanghaiTech
University for the assistance in NMR analysis.
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
56
57
[7] Y. Zhang, L. Zhang, X. Zhang, D. Yang, C. Du, L. Wan, C. Au, J. Chen, M.
Xie, New J. Chem. 2020, 44, 15202.
[8] a) X. Chen, K. Geng, R. Liu, K. T. Tan, Y. Gong, Z. Li, S. Tao, Q. Jiang, D.
Jiang, Angew. Chem. Int. Ed. 2020, 59, 5050; b) C. S. Diercks, O. M. Yaghi,
Science 2017, 355; c) X. Feng, X. Ding, D. Jiang, Chem. Soc. Rev. 2012, 41,
6010; d) H. Wang, H. Wang, Z. Wang, L. Tang, G. Zeng, P. Xu, M. Chen, T.
Xiong, C. Zhou, X. Li, D. Huang, Y. Zhu, Z. Wang, J. Tang, Chem. Soc. Rev.
2020, 49, 4135; e) S. Y. Ding, W. Wang, Chem. Soc. Rev. 2013, 42, 548;
f) Y. Li, W. Chen, G. Xing, D. Jiang, L. Chen, Chem. Soc. Rev. 2020, 49,
2852; g) X. Chen, K. Geng, R. Liu, K. T. Tan, Y. Gong, Z. Li, S. Tao, Q. Jiang,
D. Jiang, Angew. Chem. Int. Ed. 2020, 59, 5050; h) H. Wang, H. Wang, Z.
Wang, L. Tang, G. Zeng, P. Xu, M. Chen, T. Xiong, C. Zhou, X. Li, D.
Huang, Y. Zhu, Z. Wang, J. Tang, Chem. Soc. Rev. 2020, 49, 4135.
[9] a) G.-B. Wang, S. Li, C.-X. Yan, F.-C. Zhu, Q.-Q. Lin, K.-H. Xie, Y. Geng, Y.-B.
Dong, J. Mater. Chem. A 2020, 8, 6957–6983; b) Z. Li, Y. Zhi, P. Shao, H.
Xia, G. Li, X. Feng, X. Chen, Z. Shi, X. Liu, Appl. Catal. B 2019, 245, 334;
c) S. Wang, Q. Sun, W. Chen, Y. Tang, B. Aguila, Y. Pan, A. Zheng, Z.
Yang, L. Wojtas, S. Ma, F.-S. Xiao, Matter 2020, 2, 416; d) Y. Zhi, Z. Wang,
Q. Zhang, H.-L. Zhang, Q. Zhang, Small 2020, 16, e2001070; e) Y. Zhi, Z.
Li, X. Feng, H. Xia, Y. Zhang, Z. Shi, Y. Mu, X. Liu, J. Mater. Chem. A 2017,
5, 22933.
Conflict of Interest
The authors declare no conflict of interest.
Keywords: Arylboronic acids · Covalent organic frameworks ·
Oxidative hydroxylation · Photocatalysis · Superoxide radical
[1] a) B. Xia, Y. Zhang, J. Ran, M. Jaroniec, S. Z. Qiao, ACS Cent. Sci. 2021, 7,
39; b) Q. Liu, L.-Z. Wu, Natl. Sci. Rev. 2017, 4, 359; c) G. Han, Y. Sun,
Mater. Today Phys. 2021, 16, 100297.
[2] a) X. Kang, X. Han, C. Yuan, C. Cheng, Y. Liu, Y. Cui, J. Am. Chem. Soc.
2020, 142, 16346; b) S. Bi, P. Thiruvengadam, S. Wei, W. Zhang, F. Zhang,
L. Gao, J. Xu, D. Wu, J.-S. Chen, J. Am. Chem. Soc. 2020, 142, 11893;
c) P. F. Wei, M. Z. Qi, Z. P. Wang, S. Y. Ding, W. Yu, Q. Liu, L. K. Wang,
H. Z. Wang, W. K. An, W. Wang, J. Am. Chem. Soc. 2018, 140, 4623; d) C.
Kokotos, I. Sideri, E. Voutyritsa, Synlett 2017, 29, 1324; e) A. A. Atia, M.
Kimura, Catalysts 2020, 10, 1262; f) I. G. T. M. Penders, Z. Amara, R.
Horvath, K. Rossen, M. Poliakoff, M. W. George, RSC Adv. 2015, 5, 6501;
g) T. Toyao, N. Ueno, K. Miyahara, Y. Matsui, T. H. Kim, Y. Horiuchi, H.
Ikeda, M. Matsuoka, Chem. Commun. 2015, 51, 16103; h) S. P. Pitre, C. D.
McTiernan, H. Ismaili, J. C. Scaiano, J. Am. Chem. Soc. 2013, 135, 13286;
i) J. A. Johnson, J. Luo, X. Zhang, Y.-S. Chen, M. D. Morton, E. Echeverría,
F. E. Torres, J. Zhang, ACS Catal. 2015, 5, 5283; j) Y. Q. Zou, J. R. Chen,
X. P. Liu, L. Q. Lu, R. L. Davis, K. A. Jorgensen, W. J. Xiao, Angew. Chem.
[10] Z. Li, S. Han, C. Li, P. Shao, H. Xia, H. Li, X. Chen, X. Feng, X. Liu, J. Mater.
Chem. A 2020, 8, 8706.
Manuscript received: February 11, 2021
Revised manuscript received: March 8, 2021
Accepted manuscript online: March 11, 2021
Eur. J. Org. Chem. 2021, 1–7
www.eurjoc.org
6
© 2021 Wiley-VCH GmbH
��
These are not the final page numbers!

FULL PAPERS
1
2
3
4
5
6
G. Xiao, W. Li, T. Chen, W.-B. Hu,
Prof. Dr. H. Yang, Dr. Y. A. Liu,
Prof. Dr. K. Wen*
7
8
1 – 7
Application of Electron-Rich
Covalent Organic Frameworks
COF-JLU25 for Photocatalytic
Aerobic Oxidative Hydroxylation
of Arylboronic Acids to Phenols
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
56
57
COF-JLU25, a COF-based photocata-
lyst comprised solely of electron-
donating units, 1,3,6,8-tetrakis(4-ami-
nophenyl)pyrene (PyTA) and 4-[4-(4-
formylmethyl)-2,5-dimethoxyphenyl]
benzaldehyde (TpDA), demonstrated
excellent photocatalytic activity with
high efficiency, robust reusability, and
low catalyst loading when used in cat-
alyzing the oxidative hydroxylation of
arylboronic acids.