The Combination of Charge and Energy Transfer Processes in MOFs for Efficient Photocatalytic Oxidative Coupling of Amines

Article abstract of DOI:10.1021/acs.inorgchem.9b03743

Combining electron and energy transfer processes is very significant for efficient photocatalytic oxidation of organic molecules. The first synthesized MOF, Co₂(L)(2,6-NDC)₂·xguest (FJI-Y10, L = bis(N-pyridyl) tetrachloroperylene per

Full text of DOI:10.1021/acs.inorgchem.9b03743

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The Combination of Charge and Energy Transfer Processes in MOFs
for Efficient Photocatalytic Oxidative Coupling of Amines
Feng-Juan Zhao, Guoliang Zhang, Zhanfeng Ju, Yan-Xi Tan,* and Daqiang Yuan*
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ABSTRACT: Combining electron and energy transfer processes is
very significant for efficient photocatalytic oxidation of organic
molecules. The first synthesized MOF, Co2(L)(2,6-NDC)2·xguest
(FJI-Y10, L = bis(N-pyridyl) tetrachloroperylene peryleneimide, 2,6-
NDC = 2,6-naphthalenedicarboxylic acid, FJI = Fujian Institute),
shows a 2-fold interpenetrated pcu net, in which the 2,6-NDC ligand
connects typical Co2(COO)4 paddle wheel clusters to form square
lattices pillared by new PDI-type ligand L. FJI-Y10 as a
heterogeneous and recyclable photocatalyst is applied for photo-
oxidation of benzylamine and its derivatives with an excellent yield of
100%, which is much higher than that (59%) of the equivalent L
ligand as a homogeneous photocatalyst under the same reaction
conditions. Such a high-efficiency photocatalytic activity attributes to the combination of charge and energy transfer processes in
catalyst FJI-Y10 during the catalytic process.
Perylene diimide (PDI) as a class of dye molecules with a
strong visible-light absorption ability and perfect chemical,
thermal, and optical stability has outstanding application in the
homogeneous process.16,19−21 The consecutive photoinduced
electron transfer (conPET) process of PDI radical anions
overcomes the current energetic limitation of visible-light
photoredox catalysis and allows the photocatalytic conversion
INTRODUCTION
■
Imines are important nitrogen-containing active intermediate
in pharmaceuticals and biosynthesis.1,2 Some reported
synthetic methods for imines, including the condensation
reaction of aldehydes or ketones with primary amines or the
aerobic oxidation coupling of alcohols with amines, usually
need unstable aldehydes and acid catalysts.3,4 Among these
traditional synthesis methods, the catalytic coupling of amines
requires external conditions such as heating, toxic oxidants
(such as 2-iodobenzoic), and raw materials (aldehydes or
ketones compound), which cause energy waste and environ-
mental pollution. From the view of green chemistry, the direct
photocatalytic oxidation of amines into imines based on
molecular oxygen as an oxidant has received tremendous
attention. Although some famous noble-metal photocatalysts,
such as ruthenium−polypyridyl complexes and iridium−
polypyridyl complexes, have been shown to have great
reactivity to the reaction by using oxygen as the oxidant,
they are expensive and poorly recyclable, both issues which
severely limit their extensive applications in catalytic syn-
thesis.5,6 In past years, some synthetic methods for imines have
been proposed to develop green catalytic processes to resolve
the above problems. Some organic dyes, such as eosin Y,7−9
porphyrin,10,11 triphenylamine,12,13 naphthalimides,14,15 per-
ylene diimide, and their derivatives16−18 have excellent hole-
transport properties and have been widely used as attractive
photocatalysts to replace noble-metal catalysts for some
photocatalytic reactions because they are usually relatively
cheaper and less toxic.
̈
of less reactive chemical bonds in organic synthesis. Konig’s
group reported that N,N-bis(2,6-diisopropylphenyl)perylene-
3,4,9,10-bis(dicarboximide) as a homogeneous catalyst pro-
duced a stable radical anion under visible-light induction and
that the subsequent excitation of the radical anion accumulated
sufficient energy for the reduced aryl halide.17 The interesting
result inspires chemists to use ligands containing PDI groups
to construct metal−organic frameworks (MOFs) for hetero-
geneous photoconversion, since the well-defined structures
constructed by metal nodes and organic linkers endow MOFs a
semiconductor-like behavior for photocatalysis undergoing
charge or energy transfer between the ligand-to-metal and
π−π* transition of the delocalized linker, etc. Recently, Duan’s
groups reported a MOF, namely, Zn-PDI, which achieved
photocatalysis for visible-light-driven oxidation of amines, due
to the synergistic effects between Zn sites and PDI arrays with
1
conPET, in which the generated O2 based on the energy
Received: December 26, 2019
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Figure 1. (a) 2D regular prismatic square-grid motif of a [Co2(2,6-NDC)2]n layer. (b) View of the 2-fold interpenetrating FJI-Y10 along the c-axis.
(c) The conceivable interaction between the host framework and benzylamine molecules based on a molecular dynamics simulation. Note that all
guest molecules and H atoms have been omitted for clarity.
Teflon-lined autoclave for 2 h and then heated at 180 °C for 3 days.
After they were washed with fresh acetonitrile (CH3CN), red crystals
were obtained in a yield of 76%.
transfer process in Zn-PDI featured as high electrophilicity to
oxidize amines to imines directly.22 Except for 2-methoxy-
benzylamine, the yields of benzylamine and its derivatives
catalyzed by Zn-PDI are lower than 74%, probably due to its
narrow porous structure. In contrast, superoxide radicals
(O2•−) derived from photogenerated electrons transfer to O2
Preparation of Co2(L)(2,6-NDC)2·xguest (FJI-Y10). A mixture
of Co(NO3)2·6H2O (15 mg), L (6.8 mg), 2,6-NDC (11.2 mg), 4 mL
of N,N-dimethylformamide (DMF), and 1 mL of CH3CN were added
to an 8 mL vial. After ultrasonication for 2 h, the mixture was sealed
and heated in a 120 °C oven for 2 days, and then it was allowed to
cool to room temperature. After they were washed with DMF, black
and purple crystals of FJI-Y10 were obtained (yield = 24 mg).
Crystal Data for FJI-Y10. C70H51Cl4Co2N8O16, M = 1519.85,
•+
can also oxidize benzylamine to PhCH2NH2 to further the
•−
coupling reaction. Therefore, the combination of O2
1
generation via charge transfer and O2 production via energy
transfer contributes to the ultimate great activity of the MOFs.
However, as we know, rare effort has been focused on this
field.23,24 In the pursuit of a more efficient catalyst for oxidative
coupling of amines, it is of great significance to develop new
PDI-type ligands for synthesizing porous MOFs with the
synergistic effect of charge and energy transfer processes.
Herein, we report the successful synthesis of new PDI-type
ligand, bis(N-pyridyl) tetrachloroperylene peryleneimide (L),
which was further used to assemble a porous MOF, namely,
Co2(L)(2,6-NDC)2·xguest (FJI-Y10), for enhancing the
catalytic efficiency of L ligand. The photocatalytic activity of
FJI-Y10 was assessed by using the amines oxide coupling
reaction under mild conditions. The combination of charge
and energy transfer processes in FJI-Y10 leads to its excellent
catalytic activity.
̅
triclinic, space group P1, a = 13.0626(3) Å, b = 13.1226(3) Å, c =
26.3129(5) Å, α = 96.8686(17)°, β = 94.9156(17)°, γ =
97.9634(18)°, V = 4410.81(16) Å3, Z = 2, Dc = 1.144 g cm−3, F000
= 2706, Cu Kα radiation, λ = 1.54178 Å, T = 115(2) K, 2θmax
=
147.3°, 65311 reflections collected, 17147 unique (Rint = 0.035). Final
GoF = 1.120, R1 = 0.0595, wR2 = 0.1595, R indices based on 14121
reflections with I > 2θ (refinement on F2).
Typical Experimental Procedure for Oxidative Coupling of
Amines. Benzylamine (1 mmol), catalyst FJI-Y10 (2 mmol % based
on L ligand), and DMF (5 mL) were introduced into a 20 mL glass
tube with a magneto. The tube was stirred at room temperature.
Subsequently, the tube was vacuumed and filled with oxygen three
times through connection with an oxygen balloon. The reaction
mixture was exposed to a 300W Xe lamp. After completion of the
reaction, 1,4-dioxane (1 mmol) as an internal standard was added into
the tube, and next, the mixture was centrifuged to separate FJI-Y10.
The yields were calculated by GC and further confirmed by GC-MS.
A series of photocatalyst-free radical scavengers were used to control
the photoactivity experiments, i.e., ammonium oxalate (AO) and
Mn(OAc)2 as the scavenger of photogenerated holes and electrons,
tertbutyl-alcohol (TBA) as the scavenger of hydroxyl radicals (•OH),
2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as the scavenger of
superoxide radical species (O2•−), and 2,2,6,6-tetramethylpiperidine
(TEMP) as the scavenger of singlet oxygen (1O2), were carried out
similarly to the photocatalytic experiments where the radical
scavengers (1 mmol) were added to the reaction system.
Electrochemical Measurements. All the electrochemical
measurements were completed on a ZM6ex electrochemical station
(Zahner, Germany) in a standard three-electrode system with a
fluoride−tin oxide (FTO) glassy electrode as the working electrode
system, a Pt electrode as the counter electrode, and a Ag/AgCl
electrode as the reference electrode. The catalyst (20 mg) was
dispersed in 0.5 mL DMF to obtain a suspension, and 20 μL of the
suspension was scattered on the prepared FTO glass with an area of
0.25 cm2. The coated FTO glass was then dried at room temperature
in air. The Mott−Schottky and photocurrent plots were collected in
0.1 M tetra-n-butylammonium hexafluorophosphate (TBAPF6) in
CH3CN solution and purged with N2 prior to measurement. The
Mott−Schottky plots of FJI-Y10 were measured at frequencies of 800,
1000, and 1500 Hz. The photocurrent signal was measured under
chopped light, and the light source was the same as that used in the
photoactivity tests described above.
EXPERIMENTAL SECTION
■
General Procedures. All chemical reagents and solvents were
commercially available and used without any purification. Thermal
gravimetric analyses (TGA) were executed at a heating rate of 10 °C/
min under nitrogen flow with a Netzsch STA 449C instrument. FT-IR
spectra were collected as KBr pellets on the Vertex70 instrument. The
powder X-ray diffraction (PXRD) patterns were obtained on a Rigaku
Mini 600 X-ray diffractometer with Cu Kα radiation (λ = 1.5406 Å);
the collecting speed was 2 °/min, and the range of 2θ was 4° to 50°.
Simulated PXRD patterns were calculated using the program Mercury
via the single-crystal data. UV−vis absorption spectra were acquired
on a PerkinElmer Lambda 950 UV−vis−NIR spectrophotometer with
reference to the white standard of BaSO4. Electron paramagnetic
resonance (EPR) spectra were obtained on a Bruker-BioSpin E500
spectrometer with a 100 kHz magnetic field under room temperature.
The N2 adsorption measurements were performed on an ASAP 2020
system. The catalytic reaction products were detected by using gas
chromatography (GC). The products were further determined and
analyzed by using the GC and mass spectrometry (GC-MS) results.
The light irradiation was obtained by a 300 W Xe lamp with a cutoff
below 420 nm.
Synthesis of Bis(N-pyridyl) Tetrachloroperylene Perylenei-
mide (L) Ligand. 1,6,7,12-Tetrachloroperylene tetracarboxylic acid
dianhydride (265 mg) and 4-aminopyridine (235 mg) were dissolved
in 10 mL of propionic acid. The mixture was stirred in a 25 mL
B
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∼22.5% under 250 °C, corresponding to the release of guest
molecules (Figure S8). The UV−vis spectrum of FJI-Y10
manifests a strong absorption band at 627.5 nm, maybe
corresponding to the π−π* transition of L ligands (Figure
S9a). The band gap energy of FJI-Y10 calculated by using the
Kubelka−Munk function is 2.10 eV (Figure S9b). The electron
paramagnetic resonance (EPR) spectrum of L shows a peak at
g = 2.003, illustrating a free radicals signal (Figure S10) and
exhibiting its ability to produce superoxide radicals (O2•−).
To explore the photocatalytic oxidative capacity of FJI-Y10
for amines, the benzylamine was chosen as a test model
substrate. The control experiments indicated that photocatalyst
FJI-Y10 and oxygen were all needed for the photooxidation of
benzylamine (Table 1, entries 1−3). In order to illustrate that
RESULTS AND DISCUSSION
■
A new ligand bis(N-pyridyl) tetrachloroperylene diimide (L)
was first synthesized through the imidization of 1,6,7,12-
tetrachloroperylene tetracarboxylic acid dianhydride and 4-
aminopyridine, forming abundant red crystals that crystallized
̅
in the triclinic space group P1. According to the single-crystal
structure, L ligand has a noncoplanar structure with a twisty
conjugate system (Figure S1a), which will increase its solubility
for synthesizing MOFs. The solvothermal reaction of ligand L,
2,6-NDC, and Co(NO3)2·6H2O in a mixed DMF/CH3CN
solvent generated compound FJI-Y10, namely, Co2(L)(2,6-
NDC)2·xguest. Single-crystal X-ray analysis indicated that FJI-
̅
Y10 crystallized in the triclinic space group P1. In the structure
of FJI-Y10, each asymmetric unit is composed of one
independent Co(II) atom, half of L, and one deprotonated
2,6-NDC ligand (Figure S1b). Each cobalt atom shows a
square pyramidal geometry, coordinating to four O atoms from
four 2,6-NDC ligands and one N atom from an L ligand. In
Figure 1a, two adjacent equivalent Co(II) atoms are connected
by four carboxylates from 2,6-NDC ligands to form a typical
paddle wheel dimer [Co2(2,6-NDC)2] with a Co(II)···Co(II)
distance of 2.67 Å.25,26 These [Co2(COO)4] dimers are
bridged by naphthalene groups from 2,6-NDC ligands to form
two-dimensional (2D) layers with a square grid, which are
further pillared by L ligands to form a porous 3D framework
with typical pcu topology (Figure S3).27 In each pcu lattice, the
Co···Co distance of 13.0769−23.6816 Å (Figure S2) provides
enough clearance space to accommodate another equivalent
network to form a 2-fold interpenetrating structure (Figure
1b).28 There are face-to-face π···π stacking with the distance of
3.51 to 3.74 Å between the phenyl rings of L and 2,6-NDC
ligands from different pcu lattices (Figure S4). For the host
framework of FJI-Y10, the largest cavity diameter, the
accessible surface area, and the accessible pore volume of the
total crystal volume are 8.17 Å (Figure S5b), 1493.75 m2/g,
and 51.4%, respectively, which are calculated by Zeo++
software.29,30
Table 1. Aerobic Photooxidation Catalyzed of Benzylamine
a
into an Imine by FJI-Y10 under Different Conditions
b
c
entry
conditions
no catalyst
no oxygen
no light
yield (%)
1
2
3
4
5
6
1
4
0
no light under 60 °C
2
FJI-Y10
L
FJI-Y10
FJI-Y10
FJI-Y10
100
59
100
97
96
d
7
8
e
f
9
a
Reaction conditions: benzylamine (1 mmol), catalyst (2 mmol %,
basing on the L), DMF (5 mL), in O2, 300 W Xe lamp with a cutoff
below 420 nm. Reaction temperature: 40 °C. Reaction time: 6 h.
b
c
Additional reaction conditions. Determined by GC areas with an
d
e
internal standard of 1,4-dioxane (1 mmol). Reused 1. Reused 2.
f
Reused 3.
On the basis of the crystal structure, FJI-Y10 possesses some
necessary factors for efficient photocatalysis, including a
photocatalytic activity center (PDI), high porosity, and open
channels. However, N2 sorption measurements are unsuccess-
ful in giving the expected BET surface area by adopting various
activated methods such as traditional solvent exchange, freeze-
drying, and even supercritical CO2 exchange (Figure S5)
because of the distortion of the framework upon solvent
removal (Figure S6), a common phenomenon observed for
porous MOFs. To further understand the interaction between
the host framework and benzylamine molecules, a molecular
dynamics simulation was performed to speculate the location
of benzylamine in the pores after diffusion, and the simulation
was further optimized using the VASP package. It is shown that
benzylamine molecules occupy the central position of the
pores and display face-to-face π···π stacking with the distance
between phenyl rings of benzylamine and 2,6-NDC ligands
measured at 3.55−3.75 Å (Figure 1c). In this case, the
successive π···π stacking interaction among benzylamine, 2,6-
NDC, and L ligands promotes charge transfer from the
electron-rich benzylamines to the electron-poor L ligands for
photocatalytic oxidative coupling of amines.
the coupling reaction of benzylamine is indeed a photocatalytic
reaction rather than a thermocatalytic reaction, the reaction
was heated at 60 °C under dark conditions for 6 h, and only
trace product was formed (Table 1, entry 4). The yield of N-
benzylidenebenzylamine was up to 100% in the presence of
FJI-Y10 and oxygen upon visible-light irradiation for 6 h in
DMF (Table 1, entry 5), which is much higher than that
(59%) of equivalent L ligands as a homogeneous photocatalyst
under the same conditions. The same result can also be seen at
the photocatalytic oxidation of heptylamine (Figure S12). The
comparative experiments indicate that the careful modification
of L fragments within metal−organic frameworks can greatly
enhance the activity of the catalyst and transform a
homogeneous catalysis into a heterogeneous catalysis to
overcome these limitations of the homogeneous process. The
photocatalytic activity of FJI-Y10 is much better than those of
other MOFs, such as the typical NH2-MIL-125(Ti) (86%),31
and Zn-PDI (74%),22 and is similar to those of PCN-22224 and
UNLPF-12.23 To prove the heterogeneous mechanism of
photocatalytic oxidation of amine, a leaching test of FJI-Y10 by
removing the solid catalyst after 2 h (yield: 48%) and
continuing reaction for another 4 h were performed, but no
further conversion was observed, proving heterogeneity of FJI-
Y10. The recyclability of the photocatalyst FJI-Y10 was also
explored via using the same batch of FJI-Y10 for three
The phase purity of FJI-Y10 is confirmed by powder X-ray
diffraction (PXRD) (Figure S6). The thermal gravimetric
analyses (TGA) curve of FJI-Y10 indicates a weight loss of
C
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a
Table 2. Aerobic FJI-Y10 Catalyzed Oxidation of Different Amines to Imines under Visible-Light Irradiation
a
Reaction conditions: substrate (1 mmol), catalyst (2 mmol %, basing on the L), O2 balloon, DMF (5 mL), Xe lamp (300 W, cutoff wavelengths
b
below 420 nm). Reaction temperature: 40 °C. Reaction time: 6 h. Determined by GC areas with an internal standard of 1,4-dioxane (1 mmol).
consecutive catalytic cycles in the reaction. The results
demonstrated that the catalytic activity of FJI-Y10 could be
maintained well after three cycles (yields: ≥96%) (Table 1,
entries 7−9). PXRD measurements indicated that the recycled
photocatalyst maintained its crystalline structure, confirming
the stability of FJI-Y10 in the catalytic system (Figure S6). The
IR spectra of free benzylamine showed an N−H stretching
vibration doublet at 3363 and 3295 cm−1. However, the N−H
stretching vibration doublet of benzylamine trapped in FJI-Y10
shows an obvious red shift to 3331 and 3260 cm−1,
respectively, indicating the possible activation and strong
adsorption of benzylamine in the pores of FJI-Y10 (Figure
S13).
After the reaction conditions were optimized by using
benzylamine as a model substrate, the heterogeneous conPET
photocatalysis expands its scope with a series of substituted
benzylamine (Table 2). FJI-Y10 can catalyze benzylamine
derivates with both electron-withdrawing and electron-
donating groups to give the corresponding imines with good-
to-excellent yields of ≥94%, (Table 2, entries 2−8), except for
2-methoxy-benzylamine, in which the −OMe group at the
ortho position dramatically reduced the yield to 50% due to the
steric effects seriously hindering the photocatalytic process
(Table 2, entries 5−7).
To further demonstrate the charge transfer process in FJI-
Y10, Mott−Schottky plots were measured at different
frequencies of 800, 1000, and 1500 Hz for FJI-Y10, and the
positive slopes of C−2−V curves elucidate that the FJI-Y10 is a
typical n-type semiconductor (Figure S14).32 Based on the
UV−vis spectra and electrochemical characterizations for FJI-
Y10, its energy diagrams of HOMO and LUMO are given in
Figure S14. Catalyst FJI-Y10 exhibits a more negative potential
of the LUMO level (−0.98 V vs NHE) than the reduction
potential of E(O2/O2•−) = −0.33 V vs NHE.24,33 Therefore,
catalyst FJI-Y10 is theoretically feasible for the photocatalytic
conversion of O2 to O2•−. The PDI groups as a visible-light
harvesting unit can contribute to the HOMO at +1.12 V vs
NHE, calculated by the Tauc plot. The relatively lower
occupied molecular orbital level guarantees a high oxidation
ability for benzylamine (E1/2(M+/M) of approximately +1.47 V
vs NHE).23,24 The photocurrent response of FJI-Y10 was
collected for several on−off cycles of visible light irradiation
(Figure S15), and the typical on−off cycles of the photocurrent
were renewable, illustrating the stability of photocatalyst FJI-
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Y10. The strong photocurrent of FJI-Y10 indicates the high
separation efficiency of photogenerated electrons. Therefore,
the high separation efficiency of photogenerated carriers and
large porosity in FJI-Y10 endow it with a superior photo-
catalytic performance.
state.23,34,35 Then, PhCH2NH2 and O2 are transformed
into highly active phenylmethanimine (PhCHNH) and
H2O2. PhCHNH and benzylamine undergo a nucleophilic
addition reaction to generate the coupled imine product and
ammonia gas.36
•+
•−
It is indispensable to explore the photocatalytic oxidation of
the amines reaction mechanism behind the above favorable
photocatalytic performance of FJI-Y10. Here, benzylamine was
used to investigate the mechanism of the photocatalytic
oxidation coupling reaction. More evidence has been collected
to capture the transfer pathway of photogenerated inter-
mediates that happened in FJI-Y10 and reactants. When
Mn(OAc)2 (quenching electrons) and TEMPO (quenching
O2•−) are added, the yields decrease to 27% and 78%,
respectively (Figure 2). These results testify that the
In addition, an induction mechanism based on singlet
oxygen (1O2) oxidation of amine is also operable.37 The
photocatalytic oxidation yield was dramatically decreased to
1
48.3% in the presence of TEMP as O2 scavenger, indicating
that 1O2 is an indispensable driver for the photocatalytic
reaction (Figure 2). In fact, the generation of 1O2 is essentially
a complex energy conversion process between long-lived
excitons and ground state (3O2) oxygen molecules.38 Based on
an energy transfer mechanism (Scheme 1), under light
irradiation, the excited state PDI* transfers energy to O2,
forming reactive oxygen species 1O2 and simultaneously
returning to its ground state. 1O2 captures two H atoms
from benzylamine, forming H2O2 and a highly active
phenylmethanimine (PhCHNH) intermediate. The coupled
imine product was generated by the nucleophilic addition
reaction between PhCHNH and benzylamine.36 Therefore,
•−
1
the combination of O2 (electrons transfer) and O2 (energy
transfer) contributes to the excellent activity of FJI-Y10.
CONCLUSIONS
■
In summary, we successfully synthesized FJI-Y10 with
photoactive PDI groups and used it for aerobic coupling of
amines reactions to form imines in the presence of molecular
oxygen under visible light. Photocatalytic experiments illustrate
that FJI-Y10 is a highly efficient heterogeneous photocatalyst
for the reaction, exhibiting great yield and excellent
recyclability of substrates to produce imines. Different
quenching experiments were further carried out to indicate
Figure 2. Different radical scavengers were used to control
photocatalytic benzylamine oxidation coupling over FJI-Y10 photo-
catalyst.
•−
generation of electrons and O2 play an important role in
the selective oxidation of amines. Based on a typical electron
transfer mechanism (Scheme 1), under light irradiation, the
that the O2 and O2•−, resulting from photoinduced energy
1
transfer and charge transfer processes of excited FJI-Y10,
should be the main reactive oxygen species. The combination
of charge and energy transfer processes in FJI-Y10 leads to the
excellent catalytic activity under ambient conditions. This work
provides an insightful understanding of charge and energy
transfers in PDI-MOFs for promoting their further research on
photocatalytic reactions.
Scheme 1. Speculated Mechanisms for the Visible Light-
Driven Oxidation of Amines: Energy Transfer (ET) and
Typical Charge Transfer (CT) Pathways
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.inorgchem.9b03743.
■
sı
Additional figures, TGA results, powder X-ray diffraction
patterns, IR spectra, and sorption isotherms (PDF)
Accession Codes
CCDC 1970996 and 1982251 contain the supplementary
crystallographic data for this paper. These data can be obtained
free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by
emailing data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
PDI groups in photocatalyst FJI-Y10 are excited to form the
excited state (PDI*). Meanwhile, the electron-rich benzyl-
amine transfers one electron to the electron-poor PDI groups
and further is oxidized to a cationic amine radical
(PhCH2NH2•+). Then, the resulting PDI•− anionic radical
transfers one electron to O2, forming reactive oxygen species
AUTHOR INFORMATION
Corresponding Authors
■
Yan-Xi Tan − State Key Laboratory of Structural Chemistry,
Fujian Institute of Research on the Structure of Matter, Chinese
Academy of Sciences, Fuzhou 350002, Fujian, China;
Email: tyx@fjirsm.ac.cn
•−
O2 and simultaneously oxidizing PDI•− to its ground
E
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Daqiang Yuan − State Key Laboratory of Structural Chemistry,
Fujian Institute of Research on the Structure of Matter, Chinese
Academy of Sciences, Fuzhou 350002, Fujian, China; Fujian
Normal University, Cangshan District, Fuzhou 350007, Fujian,
China; orcid.org/0000-0003-4627-072X; Email: ydq@
fjirsm.ac.cn
Authors
Feng-Juan Zhao − State Key Laboratory of Structural
Chemistry, Fujian Institute of Research on the Structure of
Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian,
China; Fujian Normal University, Cangshan District, Fuzhou
350007, Fujian, China
Guoliang Zhang − School of Mechanical Engineering, Tianjin
University of Technology and Education, Tianjin 300222,
China
Zhanfeng Ju − State Key Laboratory of Structural Chemistry,
Fujian Institute of Research on the Structure of Matter, Chinese
Academy of Sciences, Fuzhou 350002, Fujian, China
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.inorgchem.9b03743
Notes
The authors declare no competing financial interest.
(16) Liu, D.; Wang, J.; Bai, X.; Zong, R.; Zhu, Y. Self-Assembled
PDINH Supramolecular System for Photocatalysis under Visible
Light. Adv. Mater. 2016, 28, 7284−7290.
ACKNOWLEDGMENTS
■
This work was financially supported by the National Natural
Science Foundation of China (21603229 and 21771177), the
Strategic Priority Research Program of the Chinese Academy
of Sciences (XDB20000000), the Key Research Program of
Frontier Sciences of the Chinese Academy of Sciences
(QYZDB-SSW-SLH019), and the fund of the Guangdong
Science and Technology Program (2017B030314002).
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halides by consecutive visible light-induced electron transfer
processes. Science 2014, 346, 725−728.
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