Visible Light Induced Selective Aerobic Formation of N-benzylidene Benzylamine over 2-aminoterephthalic Acid Sensitized {110}-Facetted BiOCl Nanosheets

Article abstract of DOI:10.1002/cctc.201901562

Surface modification with a photosensitizer is an efficient way to improve visible light activity of wide band gap semiconductors, but is rarely applied in photocatalytic organic synthesis. Herein, we report that 2-aminoterephthalic acid (ATA) sensitized

Full text of DOI:10.1002/cctc.201901562

Accepted Article
Title: Visible light induced selective aerobic formation of N-
benzylidenebenzylamine over 2-aminoterephthalic acid
sensitized {110}-facetted BiOCl nanosheets
Authors: Aijuan Han, Jiulong Sun, Hongwei Zhang, Gaik-Khuan
Chuah, and Stephan Jaenicke
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Visible light induced selective aerobic formation of N-benzylidene
benzylamine over 2-aminoterephthalic acid sensitized {110}-
facetted BiOCl nanosheets
Aijuan Han,†[a,b] Jiulong Sun,†[a] Hongwei Zhang,†[a] Gaik-Khuan Chuah* and Stephan Jaenicke*
[a]
[a]
†These authors contributed equally.
Abstract: Surface modification with a photosensitizer is an efficient
way to improve visible light activity of wide band gap semiconductors,
but is rarely applied in photocatalytic organic synthesis. Herein, we
report that 2-aminoterephthalic acid (ATA) sensitized {110}-facetted
BiOCl nanosheets, prepared by a solvothermal method, exhibit
outstanding photocatalytic activity for the selective oxidative coupling
of benzylamine to N-benzylidenebenzylamine under visible light. UV-
vis diffuse reflectance spectra confirmed that the introduction of ATA
extends the light adsorption of wide band gap BiOCl into the visible
light region. Characterization by HRTEM and SAED indicated that the
samples were predominantly terminated by {110} facets. BiOCl
incorporating 0.18% ATA exhibited superior activity for the
photocatalytic oxidation of benzylamine under visible light, with 100 %
conversion and 100 % selectivity towards N-benzylidenebenzylamine.
The catalyst exhibited excellent recyclability and works well with other
substituted benzylamines, suggesting its robust and universal nature.
This work provides an example for the application of a low-cost and
highly efficient visible-light-responsive photocatalyst in organic
synthesis.
organic compounds.[6] Conventional methods for their synthesis
usually involve high temperatures, expensive precious metals or
hazardous oxidants.[7] Hence, the development of green, efficient
and selective catalysts to produce imines is highly desired.
BiOCl is widely used for the photocatalytic degradation of
organic pollutants due to its superior photocatalytic activity, low
cost, nontoxic and robust nature. First reported as a photocatalyst
in 2006,[ it has attracted the attention of photochemists and
nanomaterial scientists with interest in synthetic reactions. It has
been reported to be efficient for the selective oxidation of benzyl
8]
alcohol,[ aerobic oxidation of secondary amines, and oxidative
coupling of primary amines.[ However, due to its the wide band
gap (3.4-3.5 eV), it can only utilize the ultraviolet (UV) region of
the solar energy, which is far less abundant than the visible range
9]
[10]
11]
(ca. 46 %, 400
– 700 nm). Surface modification with
photosensitizers has been explored as an effective way to
improve the visible light absorption of BiOCl.[12] However, this
strategy has only been investigated for environmental purification.
We were motivated to explore its application in photocatalytic
synthesis, such as the aerobic oxidation of primary amines.
Herein, we report 2-aminoterephthalic acid (ATA) modified
{
110}-dominated BiOCl nanosheets as an efficient visible light
Introduction
induced photocatalyst where ATA works as a photosensitizer.
The material, synthesized by a solvothermal method, enhanced
the selective oxidative coupling of benzylamine as compared to
the pure BiOCl. The facile formation of the desired product, N-
benzylidenebenzylamine, at room temperature under visible light
irradiation using atmospheric air highlights the potential of surface
modified BiOCl as an outstanding photocatalyst for organic
synthesis.
Ever since Ciamician’s realization that sunlight can be used as an
abundant and renewable energy source to promote chemical
reactions,[ photocatalytic synthesis has attracted much attention
as organic reactions can be carried out under mild and green
conditions due to the lower activation energies. Especially,
heterogeneous photocatalysis with semiconductors is a hot topic
in this area due to additional merits of stability, ease of recovery
1]
and reusability.[2] However, only a few materials, such as TiO
,[3]
2
,[4] MOF,[5] are reported to be effective for a limited type of
3 4
C N
Results and Discussion
organic reactions. The exploration of highly efficient and selective
photocatalysts for specific organic reactions remains a big
challenge. Imines are important synthetic intermediates for
pharmaceuticals and biologically active nitrogen-containing
The powder x-ray diffraction patterns (Figure 1) of the ATA-
modified BiOCl samples are similar to that of pure BiOCl,
matching well with tetragonal BiOCl (JCPDS No. 06-0249). No
other compounds were formed when ATA was added in the
o
synthetic procedure. The most intense peak at 2θ of 32.7 can be
[
a]
b]
Dr. Aijuan Han, Dr. Jiulong Sun, Dr. Hongwei Zhang, Prof. Gaik-
Khuan Chuah, Prof. Stephan Jaenicke
Department of Chemistry
assigned to the (110) plane. The unusually high intensity of this
peak indicates a preferential growth under the solvothermal
synthesis conditions. In comparison, the (00x) peaks were
relatively more intense for the hydrothermally synthesized ATA-
National University of SIngapore
3
Science Drive, Singapore, 117543
E-mail: chmcgk@nus.edu.sg, chmsj@nus.edu.sg
Prof. Aijuan Han
State Key Laboratory of Chemical Resource Engineering
Beijing University of Chemical Technology
Beijing 100029, China
2
BiOCl-H O. This indicates a different preferential growth pattern
[
of the crystal planes when water was used as the solvent.
Thermogravimetric analysis (TGA) was performed to assess the
amount of ATA incorporated in the samples (Figure S1). The
weight percentage of ATA in the sample was calculated from the
weight loss between 100 °C to 600 °C (Table 1). The ATA content
Supporting information for this article is given via a link at the end of
the document.
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in the samples could be easily controlled from 0.18 to 2.2 % by
varying the concentration of ATA in the solvothermal mixture from
(a)
(b)
0.65 to 6.5 %. Around 28 to 34 % of the ATA were incorporated
when using the solvothermal process. However, almost no ATA
was incorporated from an aqueous medium (sample ATA-BiOCl-
H O).
2
1
µm
1 µm
(c)
(d)
ATA-BiOCl-H O
2
2.2% ATA-BiOCl
1.0% ATA-BiOCl
1
00 nm
1 µm
0.18% ATA-
Figure 2. FESEM images of (a) BiOCl (b) 0.18% ATA-BiOCl (c) 2.2% ATA-
2
BiOCl and (d) ATA-BiOCl-H O.
BiOCl
10
20
30
40
50
60
70
80
_
2
theta / °
(a)
(b)
(
110)
(
113)
Figure 1. XRD patterns of BiOCl, ATA-BiOCl and ATA-BiOCl-H
2
O.
0.369 nm
47o
BiOCl (002)
Scanning electron microscopy analysis revealed that pure
BiOCl consisted of 30 nm thick nanosheets, which assembled into
microspheres (Figure 2a). When modified with 2-
aminoterephthalic acid, BiOCl exhibited a more open morphology,
with nanosheets aggregated into flowers. In 0.18% ATA-BiOCl,
the flowers are composed of 10-20 nm wide and 200-400 nm thick
nanosheets (Figure 2b). With higher amount of ATA in 2.2% ATA-
BiOCl, the flowers became even more open (Figure 2c). As a
2
nm
2 1/nm
(c)
(d)
2
consequence, the surface area increased from 30.3 m /g for pure
2
BiOCl to 43.9 m /g for 2.2% ATA-BiOCl. In contrast, the
2
morphology of ATA-BiOCl-H O consists of randomly stacked
Bi
Cl
O
nanosheets with 0.5-2 µm width and 90-150 nm thickness (Figure
2
2
d). Its surface area is low, only 1.50 m /g. High resolution
Figure 3. (a) HRTEM and (b) SAED of 0.18% ATA-BiOCl, and (c) top and (d)
side views of (110) plane of BiOCl.
transmission electron microscopy was used to deduce the
exposed facet of the BiOCl samples. For 0.18% ATA-BiOCl, the
clear lattice fringes with an interplanar lattice spacing of 0.369 nm
corresponds to the (002) plane of tetragonal BiOCl (Figure 3a). In
the corresponding selected area electron diffraction (SAED)
(
110) planes have a more open structure with higher accessibility
to the underlying Bi atoms. This feature may aid the incorporation
of 2-aminoterephthalic acid to the (110)-dominated sample.
The absorption spectra of the ATA-modified BiOCl samples
show absorption into the visible region, whereas pure BiOCl
absorbs only below 360 nm (Figure 4). The light absorption
between 360 nm and 460 nm for ATA-BiOCl samples coincides
with that of pure ATA and increases with higher ATA weight
percentage in the sample. However, for the hydrothermally
�
pattern, the bright spots can be assigned to the (110) and (113)
planes, while the labelled angle of 47° agrees with the theoretical
value between the (110) and (113) plane (Figure 3b). Therefore,
�
the diffraction spots are indexed to the [110] zone axis. This
indicates that the {110} facet dominates in the 0.18% ATA-BiOCl
nanosheets, which is consistent with the XRD results where the
110) peak is the most intense peak. Similarly, the dominant
exposed facet of ATA-BiOCl-H O was deduced to be {001}
Figure S2). From the crystal structure of the (110) and (001)
planes (Figures 3c & d and Figures S2c & d), it is obvious that the
(
2
2
synthesized ATA-BiOCl-H O, no absorption was observed
(
between 360-460 nm in agreement with thermogravimetric
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ChemCatChem
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analyses showing that very little ATA had been incorporated in
the sample. The band gap energy was estimated from the
Table 1. Physical properties of 2-aminoterephthalic acid-doped BiOCl.
2
1/η
Surf. Area (m /g)
ATA (wt. %)
E
g
(eV)
intercept of a (F(R )•hν) versus hν plot, where F(R ) = (1 -
∞
∞
R
∞
)
2
/2 R
∞ ∞ 4
, R = the reflectance of the sample using BaSO as a
BiOCl
30.3
32.5
38.0
43.9
1.50
0
3.54
3.52
3.48
3.48
3.54
[13]
reference, ν = light frequency, and η= 2 for an indirect transition.
A new band gap at around 2.4 eV appeared besides the intrinsic
band gap of BiOCl around 3.5 eV (Table 1).
The FTIR spectrum of BiOCl shows an absorption band
at ~510 cm−1 which is typical of the compound and can be
assigned to the symmetrical stretching vibration of the O–Bi
bond.[ 2-Aminoterephthalic acid comprised two sharp bands at
0.18% ATA-BiOCl
1.0% ATA-BiOCl
2.2% ATA-BiOCl
0.18
1.00
2.22
0
14]
2
ATA-BiOCl-H O
3
505 and 3392 cm-1 which are assigned to the asymmetric and
symmetric stretching vibrations of the NH
2
group, respectively.[15a]
1
1
1
4
2
0
8
6
4
2
0
In addition, the bands at 1691 cm-1 and 1317 cm-1 correspond to
the C=O and C-O stretching vibrations, respectively.[
BiOCl
15b]
The NH
2
0
1
2
.18% ATA-BiOCl
.0% ATA-BiOCl
.2% ATA-BiOCl
bands could not be observed in the 0.18% ATA-BiOCl sample due
to the broad peak from 3300 cm-1 to 3600 cm-1 caused by O-H
stretching of adsorbed water. However, the C=O and C-O bands
could be observed, indicating the existence of 2-
aminoterephthalic acid in the sample. Compared to ATA, there
ATA-BiOCl-H2O
ATA
was a shift in the position of the bands. The C=O band was shifted
to 1616 cm-1 while the C-O band was shifted to a higher
-1
wavenumber, 1362 cm . These shifts suggest a conjugation
effect which increases the single-bond character of the C=O
bonds and the double-bond character of the C-O bonds. X-ray
photoelectron spectroscopy was further carried out to detect the
surface species on ATA-BiOCl. Two peaks can be observed in
the C 1s spectrum of ATA. The peak at 284.7 eV can be assigned
to the aromatic carbons of the ATA molecule while the second
2
00
400
600
800
peak at 288.7 eV fits well with the binding energy for carbon of the
Wavelength / nm
[16]
–COOH group.
The two peaks were also present in 0.18%
ATA-BiOCl, confirming the presence of ATA at the surface of
BiOCl. However, the carboxyl C is shifted to a lower binding
energy, ~288.5 eV, indicating that the ATA molecule may be in
contact with the BiOCl through the -COOH group. The O 1s
spectrum of 0.18% ATA-BiOCl further proves this point. The
broad oxygen peak can be deconvoluted into three peaks. The
peak at 529.9 eV originates from the oxygen in BiOCl. The other
two higher binding energy peaks at 531.1 eV and 532.6 eV can
be attributed to the oxygen atoms of the –COOH group in ATA.
They are also shifted to lower binding energy compared to the O
Figure 4. Kubelka Munk plots of BiOCl and ATA-BiOCl samples.
ATA
1s signal in ATA. Hence, it can be inferred that 2-
aminoterephthalic acid adsorbs on the {110}-dominated BiOCl
nanosheets surface through interaction between its –COOH
group and the Bi atoms of BiOCl.
0.18% ATA-BiOCl
To assess the photocatalytic performance of ATA-BiOCl
samples in organic synthesis, the aerobic benzylamine oxidation
was used as a probe reaction (Table 2). There was essentially no
reaction in the absence of catalyst (Table 2, entry 1), confirming
that benzylamine is stable under visible light irradiation. Only a
negligible amount of imines was detected without light irradiation,
indicating that both photons and the catalyst are required for the
reaction. Pure BiOCl was able to photocatalyze the reaction under
visible light because the adsorption of benzylamine lowered the
excitation energy. This is analogous to the visible light response
BiOCl
600
3
2800
2000
1200
400
Wavenumber / cm-1
Figure 5. FT-IR spectra of BiOCl, 2-aminoterephthalic acid and 0.18%
ATA/BiOCl.
in TiO where its interaction with benzylamine led to a surface
2
charge complex with its donor level above the valence band of the
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semiconductor.[17] However, as the concentration of benzylamine
decreased with time, the reaction became rather slow, and the
conversion did not exceed 78 % after 24 h although the selectivity
to the oxidative coupling product, N-benzylidenebenzylamine,
was as high as 100 % (Table 2, entry 4). While no reaction was
observed with only 2-aminoterephthalic acid, the modification of
BiOCl with ATA significantly improved the activity due to the
enhanced visible light absorbance. The solvothermally-
synthesized ATA-BiOCl samples displayed 100 % conversion
after 24 h. The kinetic profile for 0.18% ATA-BiOCl shows that
during the reaction, the concentration of benzylimine built up to a
maximum before decreasing at longer times (Figure S4). After
conditions, outperforming materials such as TiO
WS
,[19] and NH -MIL-125[20] (Table S1). Among non-noble metal
,[3a] Nb ,[18]
O
2 2 5
2
2
containing catalysts, only BiOBr recently reported by our group
can achieve comparable yield under visible light irradiation at
room temperature with atmospheric oxygen (Table S1).[11] Hence,
this work provides a good example where the improvement in the
photocatalytic activity of a dye-sensitized semiconductor can be
successfully applied to organic synthesis.
Different solvents were investigated using 0.18% ATA-BiOCl
as the photocatalyst (Table 2, entries 5, 9-12). Only 18.5 %
conversion could be achieved after 24 h in water although the
selectivity to N-benzylidenebenzylamine, was 100 %. In methanol,
the conversion was 100 %, but the selectivity was only 20.4 % as
benzylimine formed the main product instead. High yields of N-
benzylidenebenzylamine could be obtained using DMF, toluene
and acetonitrile (ACN). It is preferable to use acetonitrile as the
solvent as its low boiling point facilitates work-up. The scope of
0.18% ATA-BiOCl was tested using various amines as substrate
(Table 3). All meta-substituted benzylamines with electron
24 h, only the desired product, N-benzylidenebenzylamine, was
detected. In comparison, both 1.0 and 2.2% ATA-BiOCl had a
lower selectivity of ~ 95 % as benzylimine was still present. ATA-
BiOCl-H O exhibited much lower activity with only 35.2 %
2
conversion. These experiments demonstrate that ATA works as a
photosensitizer in ATA-BiOCl. The quantum efficiencies (QE) are
calculated (Table 2). The higher QE for ATA-BiOCl samples
compared to BiOCl indicates that the visible light utilization
efficiency of BiOCl is enhanced through the modification of ATA.
The best catalyst is the 0.18% ATA-BiOCl which could achieve
3 3
donating group (-CH , -OCH ) or electron withdrawing group (–Cl),
reacted with similarly high conversion and selectivity as the
unsubstituted benzylamine. Ortho-methyl benzylamine reacted
with 99 % conversion and 94.8 % selectivity. In comparison, only
13-35% selectivity was obtained for para-substituted congeners.
100 % selectivity towards N-benzylidenebenzylamine. As a
selective photocatalyst for the aerobic oxidation of benzylamine,
it ranks very highly for its activity and selectivity under ambient
Table 3. Selective oxidation of various benzylamines over 0.18% ATA-BiOCl
Table 2. Photocatalytic oxidation of benzylamine
NH2
100 mg cat.
N
R
R
R
NH2
100 mg cat.
N
visible light
air
visible light
air
Entry
-R
Conv. (%)
100
Sel. (%)
100
1
2
3
4
5
6
7
H
Entry
Catalyst
Solvent
Conv. (%)
−
Sel. (%)
−
QE (%)
−
o-CH
3
99.0
100
94.8
100
1
2a
3
4
5
6
7
8
9
No catalyst
ACN
ACN
ACN
ACN
ACN
ACN
ACN
ACN
m-CH
p-CH
3
0.18% ATA-BiOCl
ATA
−
−
−
3
91.2
100
35.0
100
−
−
−
m-OCH
m-Cl
3
BiOCl
78.2
100
100
100
35.2
11.2
99.1
96.8
98.0
100
100
95.3
94.8
100
100
20.4
100
100
2.19
2.80
2.80
2.80
0.98
0.31
2.77
2.71
2.74
100
100
0.18% ATA-BiOCl
1.0% ATA-BiOCl
2.2% ATA-BiOCl
p-F
97.3
13.0
Condition: 0.1 mmol substrate 100 mg 0.18% ATA-BiOCl, 5 ml ACN, 15 W
fluorescent lamp (Philips), 24 h, 25 °C.
2
ATA-BiOCl-H O
Based on the above, a mechanism was proposed to explain
the activity of the ATA-modified BiOCl (Figure 6). Upon visible
light irradiation, initiation of the ATA photosensitizer occurs with
the excitation of an electron from the HOMO to LUMO. The
excited electron is transferred into the conduction band (CB) of
0.18% ATA-BiOCl
0.18% ATA-BiOCl
0.18% ATA-BiOCl
0.18% ATA-BiOCl
2
H O
10
11
12
methanol
toluene
DMF
BiOCl, where it can migrate to the surface and reduce O
the superoxide •O -
2
to form
2
radical. In turn, the empty LUMO of ATA can
accept an electron from benzylamine, oxidizing it to benzyl
ammonium cation radical. Reaction of benzylamonium cation
Condition: 0.1 mmol benzylamine, 100 mg catalyst, 5 ml solvent, 15 W
fluorescent lamp (Philips), 24 h, 25 °C. Without light irradiation
a
radical with the superoxide anion radical forms H O2 and
2
benzylimine which was observed as an intermediate in the
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formed aggregates of BiOCl nanosheets with {110}-dominant
exposed facet. The adsorption of 2-aminoterephthalic acid on the
{110} facets serves as a photosensitizer to extend the light
absorption into the visible region. A 0.18 wt% loading of 2-
aminoterephthalic acid on BiOCl was found to be optimum,
showing excellent photoactivity for the oxidation of benzylamine
-
e-
O2
O
O
2
2
NH
e-
NH2
-

H2O2
NH3
NH2
ATA
NH2
N
with full conversion and 100
%
selectivity to N-
BiOCl
benzylidenebenzylamine after 24 h at room temperature using
atomospheric air as oxygen source. Other substituted
benzylamines especially at the meta-position were oxidized with
similarly high yields. XRD and TGA results show that the 0.18%
ATA-BiOCl material was robust and the recycled catalyst
maintained its activity in reuse. This work highlights the use of the
dye-sensitization method to form highly efficient visible light
activated photocatalysts for imine synthesis.
Figure. 6 Proposed mechanism of benzylamine oxidation over ATA-BiOCl.
reaction. The benzylimine molecule can further react with
benzylamine to form the final product, N-benzylidenebenzylamine.
The material can be easily recycled by filtration after the
photocatalytic reaction followed by an acetone wash. No obvious
change was observed in its x-ray diffraction pattern (Figure S5),
C 1s and O 1s spectra (Figure S6) and FTIR spectrum (Figure S7)
after the recycle. The recovered ATA-BiOCl material exhibited
excellent stability, with nearly no decrease in conversion and
selectivity after four cycles (Figure 7). TGA showed that the
Experimental Section
Sample preparation. All the reagents were of analytical grade and were
used without further purification. Typically, 2-aminoterephthalic acid
(0.0362 g, 0.2 mmol) and Bi(NO
3 3
) (0.97 g, 2.0 mmol) were added into a
10 ml solution containing dimethylformamide (5 ml) and methanol (5 ml).
o
weight loss between 100-600 C, where the organic components
NaCl (0.117 g, 2 mmol) was added into another 10 ml solution containing
dimethylformamide (4.95 ml), dry methanol (4.95 ml) and water (0.1 ml).
The NaCl solution was added dropwise under vigorous stirring and the
suspension was stirred for 30 min at room temperature, transferred to a 30
decompose, is slightly higher for the recycled 0.18% ATA-BiOCl
than for the virgin material. This shows that the ATA was not lost
from the material; instead, a tiny amount of reaction products may
have been adsorbed on the recycled catalyst. This further attests
to the stability of ATA on the surface of BiOCl during the reaction,
demonstrating the robust nature of this material.
o
ml autoclave and heated at 120 C for 16 h. A yellow powder was obtained,
which was filtered and washed with ethanol. The precipitate was then dried
at 100 °C overnight. Samples with different amounts of 2-
aminoterephthalic acid varying from 0.02 mmol to 0.2 mmol were also
prepared. The samples are denoted as x% ATA-BiOCl, where x% is the
weight percentage of 2-aminoterephthalic acid in the sample, determined
by TGA analysis. Pure BiOCl was synthesized by this method but without
adding 2-aminoterephthalic acid. To establish the essential role of solvent
Conv.
Sel.
2
in this synthetic method, a sample (ATA-BiOCl-H O) was synthesized with
0
.2 mmol ATA using H O as the sole solvent.
2
100
8
0
Characterization. Powder X-ray diffraction measurements were carried
out on a Siemens D5005 diffractometer with Cu-Kα radiation over a 2θ
range from 10 to 80° using a step size of 0.02 °s-1 and a dwell time of 1 s
per step. Nitrogen adsorption and desorption isotherms were measured at
60
40
196 oC using a TriStar 3000 v5.02 (Micromeritics) porosimeter. The
-
surface area was calculated using the Brunauer-Emmett-Teller (BET)
equation. Scanning electron micrographs were obtained using a JEOL
JSM-6701F SEM (field-emission) microscope. Diffuse reflectance spectra
were measured with a Shimadzu UV-2450 UV-vis spectrophotometer
2
0
0
using BaSO
4
as a reference. Infrared spectra of the framework vibrations
4
-1
(4000 - 400 cm ) were obtained with a Bio-Rad FTS 165 FT-IR
3
spectrometer using the potassium bromide (KBr) pellet technique. The X-
ray photoelectron spectroscopy (XPS) was performed on Thermo Electron
ESCALAB 250. Binding energies (BE) were calibrated by setting the
measured BE of C 1s to 284.8 eV.
2
1
Fig. 7 Photoactivity of recycled 0.18% ATA-BiOCl.
Photocatalytic activity. The photocatalytic amine oxidation was
performed in a sealed glass tube fitted with a needle at the top to connect
to atmospheric air. 100 mg of the photocatalyst was suspended in 5 ml
acetonitrile containing 0.1 mmol benzylamine. A 15 W Philips fluorescent
lamp was irradiated from the side of the tube (the distance of lamp and
Conclusions
tube is 2.5 cm) at room temperature. The photon flux was determined with
the potassium ferrioxalate actinometer system assuming a Fe3+ quantum
yield of 1.11. At different time intervals, aliquots of 0.2 ml were sampled
In summary, 2-aminoterephthalic acid modified BiOCl was
synthesized using a one-pot solvothermal method. The material
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ChemCatChem
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and filtered with a syringe filter. The filtrates were analyzed by gas
chromatography (HP 6950N) equipped with a HP-5 column and a FID
detector. GCMS (Shimadzu GCMS-QP5000) was used to identify the
substrate and products.
[7]
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This article is protected by copyright. All rights reserved.

ChemCatChem
10.1002/cctc.201901562
FULL PAPER
FULL PAPER
†
†
This work reports on a one-pot
solvothermal method to form 2-
aminoterephthalic acid modified
bismuth oxychloride nanosheets with
exposed {110}-facets. The 2-
aminoterephthalic acid acts as a
photosensitizer, transforming the
composite to an excellent visible light
photocatalyst for the aerobic oxidative
coupling of benzylamine to N-
benzylidenebenzylamine at room
temperature using oxygen from air as
the oxidant.
Aijuan Han, Jiulong Sun, Hongwei
†
Zhang, Gaik-Khuan Chuah,* Stephan
e-
Jaenicke*
O2
e-
Page No. – Page No.
O -
2

Visible light induced selective
aerobic oxidation of
ATA
benzylamine over 2-
BiOCl
aminoterephthalic acid
sensitized {110}-facetted BiOCl
nanosheets
NH
3
NH2 Air, RT
N
2
NH
3
, H
2 2
O
Excellent yiel
This article is protected by copyright. All rights reserved.