CuI@UiO-67-IM: A MOF-Based Bifunctional Composite Triphase-Transfer Catalyst for Sequential One-Pot Azide-Alkyne Cycloaddition in Water

Article abstract of DOI:10.1021/acs.inorgchem.7b01025

A CuI-loaded and n-pentadecyl-attached imidazolium salt decorated UiO-67-type metal-organic framework (CuI@UiO-67-IM, 2) based on a new premodified ligand L (n-pentadecyl-attached imidazolium (IM) decorated dicarboxylic acid) and ZrCl₄ is reported. Compound 2 can be a bifunctional composite heterogeneous phase-transfer catalyst to promote the azide-alkyne cycloaddition (H₂O, air, 80 °C) from corresponding halogenated compounds and sodium azide as a sequential one-pot procedure with high yields and excellent regioselectivity.

Full text of DOI:10.1021/acs.inorgchem.7b01025

Article
pubs.acs.org/IC
CuI@UiO-67-IM: A MOF-Based Bifunctional Composite Triphase-
Transfer Catalyst for Sequential One-Pot Azide−Alkyne
Cycloaddition in Water
Yu-Hong Hu,† Jian-Cheng Wang,† Song Yang, Yan-An Li, and Yu-Bin Dong*
College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Centre of Functionalized Probes for
Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong
Normal University, Jinan 250014, P. R. China
S
* Supporting Information
ABSTRACT: A CuI-loaded and n-pentadecyl-attached imidazolium
salt decorated UiO-67-type metal−organic framework (CuI@UiO-67-
IM, 2) based on a new premodified ligand L (n-pentadecyl-attached
imidazolium (IM) decorated dicarboxylic acid) and ZrCl4 is reported.
Compound 2 can be a bifunctional composite heterogeneous phase-
transfer catalyst to promote the azide−alkyne cycloaddition (H2O, air,
80 °C) from corresponding halogenated compounds and sodium azide
as a sequential one-pot procedure with high yields and excellent
regioselectivity.
access to new types of multifunctional heterogeneous catalysts
for tandem reactions under PTC conditions. The multistep
reactions performed in a one-pot system are of economical and
environmental interest since they avoid costly separation and
purification of intermediate products while involving less
investment and energy consumption.7
In this contribution, we report a CuI-loaded UiO-67-type
MOF (CuI@UiO-67-IM, 2) that is decorated with an n-
pentadecyl-attached imidazolium salt via direct ligand function-
alization. Compound 2 can be a highly efficient heterogeneous
triphase-transfer catalyst to promote the sequential one-pot
azide−alkyne cycloaddition (CuAAC) in water under air
atmosphere.
INTRODUCTION
■
Phase-transfer catalysis (PTC) is a very useful synthetic
approach that generally features many advantages such as an
eco-friendly solvent system (usually water), simple reaction
procedure, and relatively mild reaction conditions.1 On the
other hand, the traditional PTC process is also associated with
some inherent deficiencies, for example, difficulty in the
separation and reutilization of the surfactant catalysts (i.e.,
quaternary ammonium salts and so on),2 which severely limit
its more extensive application scope. In contrast to traditional
phase-transfer catalysts, solid particles are more easily separable
and recoverable and have been shown to stabilize aqueous−
organic emulsions.3 Thus, the development of new types of
solid-phase-transfer catalysts could be an effective alternative
approach to address such issues.
Recently, we developed a new type of metal−organic
framework (MOF)-based solid-phase-transfer catalysts (termed
triphase catalysts) via a postsynthetic approach for PTC.4
However, the postsynthetic method in some cases leads to the
organic functional group transformation with lower yields,
which is clearly a result of the inherent imperfection of the
heterogeneous solid−liquid reactions. Therefore, the synthesis
of the target MOFs based on the premodified ligands with
surfactant functional groups might be an effective way to solve
this problem.5 In addition, as porous materials, MOFs can be
the supports to upload active catalytic species to result in MOF-
supported composite heterogeneous catalysts.6 Therefore, the
synergistic cooperation of the surfactant-decorated MOF
supports and the encapsulated catalytic species would allow
EXPERIMENTAL SECTION
■
Materials and Instrumentation. All chemicals were obtained
from commercial sources (Acros) and used without further
purification. Ligand (L) synthesis is described in the Supporting
1
Information. H NMR data were collected on a Bruker Avance-400
spectrometer. Chemical shifts are reported in δ relative to TMS.
Infrared spectra were obtained in the 400−4000 cm−1 range using a
Bruker ALPHA FT-IR spectrometer. Elemental analyses were
performed on a PerkinElmer model 2400 analyzer. ICP measurements
were performed on an IRIS Interpid (II) XSP and NU AttoM. HRMS
analysis was carried out on a Bruker maxis UHR-TOF ultra-high-
resolution quadrupole-time-of-flight mass spectrometer. Thermogravi-
metric analyses were carried out on a TA Instrument Q5 simultaneous
Received: April 23, 2017
© XXXX American Chemical Society
A
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
TGA under flowing nitrogen at a heating rate of 10 °C/min. XRPD
patterns were obtained on a D8 ADVANCE powder X-ray
diffractometer (PXRD) with Cu Kα radiation (λ = 1.5405 Å). The
scanning electron microscopy (SEM) micrographs were recorded on a
Gemini Zeiss Supra TM scanning electron microscope equipped with
an energy-dispersive X-ray detector (EDS).
Scheme 1. Scheme Representation of Synthesis of L, UiO-
67-IM (1), and CuI@UiO-67-IM (2)
Synthesis of UiO-67-IM (1). ZrCl4 (29 mg, 0.12 mmol) and 50
equiv of acetic acid (0.34 mL) were dissolved in DMF (5 mL) by using
ultrasound for about 10 min. L (68 mg, 0.12 mmol) was added to the
clear solution in an equimolar ratio with regard to ZrCl4. The tightly
capped flasks were kept in an oven at 120 °C under static conditions.
After 24 h, the reaction system was cooled to room temperature, and
the precipitate was isolated by centrifugation. The solids were
suspended in fresh DMF (10 mL). After being allowed to stand at
room temperature for 5 h, the suspension was centrifuged, and the
solvent was decanted off. The obtained particles were washed with
ethanol (10 mL) several times in the same way as described for
washing with DMF. Finally, the solids were dried under reduced
pressure to generate the as-synthesized 1 crystals. Yield: 47.3%. IR
(KBr pellet cm−1): 2955 (w), 2924 (w), 1721 (vs), 1604 (m), 1435
(s), 1399 (m), 1285 (s), 1248 (m), 1213 (w), 1187 (m), 1110 (m),
978 (w), 755 (m), 626 (w). Anal. Calcd for Zr6O4(OH)4L6: C, 58.08;
H, 6.75; N, 4.11. Found: C, 57.89; H, 6.99; N, 4.02.
Sythesis of CuI@UiO-67-IM (2). Compound 1 (10 mg) was
added in a CuI (5 mg, 0.026 mmol) solution of CH3CN (5 mL) at
room temperature. The mixture was stirred at room temperature for 2
h. The obtained solids were dried at 80 °C for 2 h to afford 2 (CuI@
UiO-67-IM). IR (KBr pellet cm−1): 3414.7 (m), 2925.7 (s), 2853.8
(m), 1596.2 (s), 1552.9 (m), 1414.7 (vs), 1153.7 (w), 774.10 (w),
662.6 (m), 513.3 (w), 457.5 (w). The formula of 2 can be described as
0.84CuI@UiO-67-IM based on ICP results (Table S1, Supporting
Information).
General Procedure for PTC Reactions Catalyzed by 2.
ArCH2X (1 mmol), NaN3 (2 mmol), H2O (2 mL), and 2 (0.02
mmol) were stirred at 80 °C for 2−4 h. After completion of the
reaction, H2O (2 mL) and CH2Cl2 (5 mL) were added in the system,
and 2 was recovered by centrifugation. After removal of the solvent of
the organic phase, the product was isolated by column on silica gel to
afford the corresponding azidated products (Supporting Information).
General Procedure for CuAAC Reactions Catalyzed by 2. A
mixture of ArCH2N3 (1 mmol), phenylacetylene (1.5 mmol), and 2
(0.02 mmol) in H2O (2 mL) was stirred at 80 °C for 2 h. After
reaction, H2O (3 mL) and CH2Cl2 (5 mL) were added in the system,
and 2 was recovered by centrifugation. After removal of the solvent of
the organic phase, the product was isolated by column on silica gel to
afford the corresponding “click” reaction products (Supporting
Information).
General Procedure for One-Pot CuAAC Reactions Catalyzed
by 2. A mixture of ArCH2X (1 mmol), NaN3 (2 mmol), and 2 (0.02
mmol) in H2O (2 mL) was heated at 80 °C for 2 h. After addition of
phenylacetylene (1.5 mmol), the mixture was stirred at 80 °C for an
additional 6 h. H2O (3 mL) and CH2Cl2 (5 mL) were added once the
reaction finished, and 2 was recovered by centrifugation. After removal
of the solvent of the organic phase, the products were purified by
column on silica gel to afford the corresponding products (Supporting
Information).
Figure 1. (a) XRPD patterns of the simulated UiO-67, measured 1,
and 2. Insets: photographs for samples 1 and 2. (b) SEM images and
EDS elemental mapping of 1 and 2. (c) Dynamic light scattering
(DLS) measurements.
the copper-catalyzed reactions. First, UiO-type MOF is known
to be very stable in aqueous media;8 second, the imidazolium
group with long linear alkyl chains is a good surfactant which is
able to enhance the interfacial surface area via emulsification4
and, consequently, facilitate the reactions between two
immiscible phases, for example, aqueous vs organic phases;
third, copper halide is known to be effective catalyst for
CuAAC.9 In this way, the advantages of MOFs, copper, and
imidazolium species would be expected to combine together to
lead to an attractive multifunctional porous catalytic material
for chemical transformation under PTC conditions.
RESULTS AND DISCUSSION
■
Synthesis and Characterization of 2. As shown in
Scheme 1, UiO-67-IM (1) was generated from an n-pentadecyl-
attached imidazolium (IM) decorated dicarboxylic acid ligand L
(Supporting Information) and ZrCl4 under solvothermal
conditions. CuI@UiO-67-IM (2) was prepared via the solution
impregnation of 1 in a CuI solution of CH3CN. Compound 2,
as a CuI-loaded and imidazolium salt decorated UiO-67-type
MOF, it was expected to be the ideal candidate to serve as a
bifunctional composite catalyst to promote not only the phase-
transfer reactions between organic and aqueous phases but also
The powder X-ray diffraction (PXRD) pattern indicates that
1 and 2 are highly crystalline, and their structure is identical to
B
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Table 1. Model Azidation Reaction of Benzyl Chloride
Catalyzed by 2
Table 2. Azidation Reactions for Different Benzyl Halides
Catalyzed by 2
a
a
entry
T (°C)
catalyst
time (h)
conv (%)
selectivity (%)
1
2
3
4
5
6
7
8
9
40
60
60
80
80
80
80
80
80
2
2
2
5
2
5
2
2
2
2
42
68
91
98
98
17
93
95
98
>99
>99
>99
>99
>99
>99
>99
>99
>99
2
2
2
2
-
CuI
CuI
1+CuI
a
Benzyl chloride (1 mmol), NaN3 (2 mmol), H2O (2 mL), catalyst (2
a
Reaction conditions: benzyl halide (1 mmol), NaN3 (2 mmol), H2O
mol %), in air. The yields were determined by GC analysis.
(2 mL), 2 (2 mol %), temperature (80 °C), and reaction time (2−4
b
that of pristine UiO-67 (Figure 1a).8a Thus, the pre-embedded
imidazolium salt with long alkyl linear chain and uploaded CuI
did not affect the UiO-67 framework formation under the
reaction conditions. Scanning electronic microscopy (SEM)
measurements showed that both 1 and 2 exhibited a regular
platelike shape and were obtained as the uniform nanoscale
particles (ca. 110 nm) (Figure 1b), which is further supported
by the dynamic light scattering (DLS) measurements (Figure
1c). In addition, 2 is stable up to ca. 150 °C, which was
supported by the thermogravimetric analysis (TGA) and
corresponding PXRD measurements (Supporting Information).
Although 2 showed much less thermostability than its pristine
UiO-67 (decomposition at 520 °C),10 it is stable enough to be
a heterogeneous catalyst for the most organic transformations.
The energy-dispersive X-ray spectrum (EDS) measurement
(Figure 1b) showed that the uploaded CuI homogeneously
distributes in 2. The uploaded copper amount in 2 was
determined by inductively coupled plasma (ICP) measure-
ments (Supporting Information). The Zr/Cu ratio in 2 is
7.14:1.00, and the corresponding formula of 2 can be described
as 0.84CuI@UiO-67-IM. The encapsulated Cu(I) species was
further confirmed by X-ray photoelectron spectroscopy (XPS).
The observation of Cu 2p3/2 peak at 933.4 eV in XPS of 2
demonstrated the copper valence is univalent (Supporting
Information).11
h). Isolated yield.
Table 3. Model Azide−Alkyne Cycloaddition Reaction
a
Catalyzed by 2
b
yield (%)
c
entry time (h) T (°C) conv (%)
IIA
IIB
TOF (h−1
)
1
2
3
2
3
2
80
80
89
89
84
99.7
99.6
98.7
0.3
0.4
1.3
22.2
14.8
20.9
100
a
Reaction conditions: benzyl azide (1 mmol), phenylacetylene (1.5
b
mmol), water (2 mL), 2 (2 mol %, 1.7 mol % Cu), in air. Isolated
yield. TOF = conversion (mmol of substrate/mmol of cat., h).
c
The permanent porosity of 2 was determined by measuring
nitrogen gas (N2) adsorption at 77 K. It is different from
pristine UiO-67, as 2 exhibits a type-II sorption behavior
(Supporting Information). The lack of hysteresis indicates that
the adsorption and desorption mechanisms are similar and that
the adsorption is reversible. The measured Brunauer−
Figure 2. (a) Photograph of a water/CuI@UiO-67-IM (2)/benzyl chloride system. It is seen that the solid particles of 2 with long flexbile alkyl
chains preferentially migrate to the interface. (b) Reaction time examination (black line) and leaching test (red line) for the benzyl chloride azidation
catalyzed by 2. (c) Reaction time examination (black line) leaching test (red line) for the azide−alkyne cycloaddition of phenylacetylene with benzyl
azide catalyzed by 2.
C
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
PTC Reactions Catalyzed by 2. On the basis of the above
observation, the PTC activity of 2 was first examined in which
the azidation of benzyl chloride with NaN3 in aqueous solution
was chosen as a model reaction to optimize the reaction
conditions. As shown in Table 1, the PTC performance of 2 in
the model azidation experiment exhibited a positive correlation
with an increase of the reaction temperature and time. For
example, the benzyl chloride conversion in the presence of 2 (2
mol %) in water increased from 42 to 68% when the
temperature was increased from 40 to 60 °C over 2 h (entries
1 and 2, Table 1). A 91% conversion was obtained when the
reaction time extended to 5 h at 60 °C (entry 3, Table 1). The
conversion, however, was enhanced up to 98% only over 2 h
when the reaction was carried out at 80 °C (entry 4, Table 1),
and no increase in conversion was observed even at longer
reaction time at this temperature (entry 5, Table 1). Notably,
the selectivity of the azidated product (IA) is always >99%
under various conditions. On the basis of these results, the
optimal azidation conditions could set as 1 mmol of benzyl
chloride, 2 mmol of NaN3, 2 mL of H2O, 2 mol % of 2, 80 °C
of temperature, and 2 h of reaction time. It is noteworthy that
the azidated product of IA was obtained in only 17% yield
without 2 (entry 6, Table 1). It is known that CuI can
effectively catalyze azidation of organic halides,13 and IA was
obtained in 93 and 95% yields with only CuI (entry 7, Table 1)
and 1+CuI (entry 8, Table 1), respectively. However, CuI was
not stable and was easily oxidized under reaction conditions
(the color changed to green-blue at 80 °C in water for 2 h),
resulting in CuI species that cannot be recycled. On the other
hand, the control experiment (entry 9, Table 1) showed that IA
can be generated in 98% yield with only 1. Because the CuI
species was encapsulated in MOF matrix, we assumed that the
catalytic activity herein is mainly ascribed to the attached
imidazolium moiety.
Table 4. Azide−alkyne Cycloaddition of Phenylacetylene
a
with Different Benzyl Azides Catalyzed by 2
a
Reaction conditions: benzyl azides (1 mmol), phenylacetylene (1.5
b
mmol), water (2 mL), 2 (2 mol %, 1.7 mol % Cu), in air. Isolated
yield. TOF = conversion (mmol of substrate/mmol of cat., h).
c
Table 5. Azide−Alkyne “Click” Reactions from
Corresponding Halogenated Compounds and Sodium Azide
a
Catalyzed by 2 in Water
As shown above, 2 possesses the hydrophilic imidazolium
moiety with linear lipophilic chains linked to the solid UiO-67
nanoparticles with hydrophilic cavities. Such nanoparticles are
indeed biphasic, which is a conspicuous characteristic of phase-
transfer catalysts and prone to stay at the liquid/liquid interface
to stabilize aqueous−organic emulsions (Figure 2a).
To gain insight into the heterogeneous nature of 2, a hot
leaching test was performed. As shown in Figure 2b, no further
reaction occurred without 2 after ignition of the azidation at 1
h, indicating that no leaching of the catalytically active sites
occurs and that 2 features a typical heterogeneous catalyst
nature.
After that, the scope and generality of the present phase-
transfer azidation was further extended to other kinds of benzyl
halides. Under the optimized reaction conditions, azidation of
different benzyl halides gave excellent yields (Table 2), which
are comparable with that of benzyl chloride. For all benzyl
halides (X = Cl and Br), the catalytic azidation reactions
smoothly proceeded and generally exhibits high conversions
with excellent selectivity. Among benzyl chlorides, −Cl (entry
3, Table 2) and −CH3 attached (entry 4, Table 2) substrates
showed relatively lower activity, and the corresponding
azidation reactions were completed over 4 h. The conversions
are only 55% for 4-chlorobenzyl chloride (entry 3, Table 2) and
79% for 4-methylbenzyl chloride (entry 4, Table 2) at 2 h,
respectively. The azidation of 4-nitrobenzyl chloride (entry 2,
Table 2) was completed over 2 h but with a 91% yield (entry 2,
Table 2), which is lower than that of benzyl chloride (98%,
entry 1, Table 2) under the same conditions. In contrast, benzyl
a
Reaction conditions: a mixture of benzyl halides (1 mmol), NaN3 (2
mmol) and 2 (2 mol %, 1.7 mol % Cu) in H2O (2 mL) was heated in
air at 80 °C for 2 h. After addition of phenylacetylene (1.5 mmol), the
reaction system was heated at 80 °C for an additional 6 h. Isolated
b
c
yield. TOF = conversion (mmol of substrate/mmol of cat., h).
Emmett−Teller surface area of 2 is only 45.1 m2/g, which is
drastically smaller than that of UiO-67 (2113 m2/g). The
corresponding pore sizes of 2 are centered at ca. 12 Å
(Supporting Information), which are also less than its parent
UiO-67 (ca. 19 Å).10 Such differences are clearly attributed to
pore clogging from the introduced imidozalium groups with
long flexible alkyl chains and also uploaded CuI species.12
D
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Figure 3. (a) Recycling test for the one-pot, two-step domino reaction based on 4-nitrobenzyl bromide and NaN3 catalyzed by 2. (b) PXRD patterns
of as-synthesized 2 and after five catalytic runs. (c) SEM image and EDS elemental mapping of 2 after catalysis.
bromides are more active for the reaction except 4-
methylbenzyl bromide (entry 8, Table 2). The excellent
azidation yields (99%) were observed in only 2 h (entries 5−
7, Table 2). It seems that the electron-withdrawing groups are
more beneficial to the 2-catalyzed azidation under the reaction
conditions.
CuAAC Reactions Catalyzed by 2. Owing to the
encapsulated CuI, we then examined the activity of 2 for
Cu(I)-catalyzed azide−alkyne cycloaddition (CuAAC) in which
the cycloaddition of phenylacetylene with benzyl azide was
chosen as model reaction. As shown in Table 3, when the
reaction was carried out in the presence of 2 (2 mol %, 1.7 mol
% Cu) at 80 °C in water under air atmosphere for 2 h
(monitored by TLC), the expected 1, 4-disubstituted triazole
(IIA) was isolated in good yield (89%, entry 1, Table 3) with
excellent regioselectivity (99.7%, entry 1, Table 3). It seems
that the longer reaction time (3 h, entry 2, Table 3) and higher
temperature (100 °C, entry 3, Table 3) were not helpful for the
1,3-dipolar cycloaddition and led to more 1,2-disubstituted
triazole (IIB).
It is similar to azidation, 2 also exhibited heterogeneous
nature for the azide−alkyne cycloaddition, which was
demonstrated by a hot filtration test. Thus, the reaction was
stopped at partial conversion (ca. 60%), and the catalyst was
quickly removed by filtration at the reaction temperature to
avoid reprecipitation from the solution of eventually leached
species. After filtration, the reaction filtrate was allowed to react
for additional 1.3 h under the same reaction conditions, but the
conversion did not increase further (Figure 2c).
Having optimized the reaction conditions, catalyst 2 was
applied to the cycloaddition reaction of phenylacetylene with
different benzyl azides equipped with either electron-with-
drawing or electron-donating groups (Table 4). In comparison
with the benzyl azide (entry 1, Table 4), higher yields (91−
99%) were obtained for those substrates containing electron-
withdrawing substituents on the benzene ring (entries 2, 3, and
5, Table 4). The lowest yield (83%, entry 4, Table 4) was
observed for the substrate with an electron-donating methyl
group. Notably, all of the reactions exhibited excellent
regioselectivity (99.7−99.9%).
only a 53% yield for 1,4-triazole was obtained. This might be
due to a side reaction of the CuI with sodium azide. This
problem, however, can be easily overcome by simply perform-
ing the reaction as a sequential one-pot procedure instead.
Indeed, when the phenylacetylene was added after the
generation of the azide, the conversion increased to 84% with
99.5% of regioselectivity under the reaction conditions.
With this sequential one-pot procedure in hand, the scope of
the method was further investigated with a range of different
benzyl halides and phenylacetylene under the optimized
reactions (Table 5). Compared to benzyl bromides (entries
5−8, Table 5), benzyl chlorides (entries 1−4, Table 5) showed
lower activity for CuAAC reactions. In addition, we found that
the benzyl halides with attached electron-withdrawing groups
(e.g., −NO2, −Cl, and −-Br) afforded the desired products in
higher isolated yields (73−99%) than those with electron-
donating groups (42−64%). Except for 4-methylbenzyl
chloride (entry 4, Table 5), the sequential one-pot reactions
for all benzyl halide substrates are highly selective, and 1,4-
disubstituted triazole isomers (IIA) were always obtained in
excellent regioselectivity (99.5 to >99.9%). In addition, larger
sized 9-(bromomethyl)anthracene was also used as the
substrate to perform this sequential one-pot reaction under
the same conditions (entry 9, Table 5). No expected azide−
alkyne cycloaddition products were obtained, suggesting that
the internal surface catalysis might be the predominant process
for this CuAAC reaction.
After that, we examined the recyclability of 2 for the one-pot,
two-step domino reaction based on 4-nitrobenzyl bromide and
NaN3 (entry 6, Table 5). After each catalytic run, the solid
catalyst of 2 was collected by centrifugation, washed with
ethanol, dried at 80 °C, and reused in the next run under the
same conditions. Within five catalytic runs, conversions of 94−
90% were obtained with >99.9% selectivity (Figure 3a). The
PXRD patterns and the SEM image of 2 after five catalytic runs
indicated that the structural integrity and morphology of 2 were
well-preserved (Figure 3b,c), and the dispersion of loaded CuI
species was still uniform in 2 based on the EDS elemental
mapping (Figure 3c). The CuI loss is only ca. 10.7%
(determined by ICP-AES), and no valence change for copper
species was detected (determined by XPS, Supporting
Information) after five catalytic cycles. Thus, 1 could be
considered as an ideal platform to load CuI, and 2 is an ideal
heterogeneous catalyst for synthesis of 1, 4-disubstituted
triazoles directly from the benzyl halides via a sequential one-
pot reaction. To date, some one-pot CuAAC examples have
recently appeared in the literature,9,14 and only one study on
One-Pot CuAAC Reactions Catalyzed by 2. Taking the
above observation into account, we finally explored the
possibility of developing a one-pot procedure for the CuAAC
directly starting from halogenated compounds and sodium
azides. In this context, benzyl bromide was chosen as the
starting benzyl halide for this one-pot CuAAC. When the
reaction was carried out at 80 °C for 12 h (monitored by TLC),
E
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Asymmetric Electrophilic Fluorination Using a Chiral Anionic Phase-
Transfer Catalyst. Science 2011, 334, 1681−1684. (d) Ooi, T.;
Uematsu, Y.; Maruoka, K. Asymmetric Strecker Reaction of Aldimines
Using Aqueous Potassium Cyanide by Phase-Transfer Catalysis of
Chiral Quaternary Ammonium Salts with a Tetranaphthyl Backbone. J.
Am. Chem. Soc. 2006, 128, 2548−2549. (e) Sharma, K.;
Wolstenhulme, P. P.; Yeo, D.; Grande-Carmona, F.; Johnston, C. P.;
Tantillo, D. J.; Smith, M. D. Cation-Controlled Enantioselective and
Diastereoselective Synthesis of Indolines: An Autoinductive Phase-
Transfer Initiated 5-endo-trig Process. J. Am. Chem. Soc. 2015, 137,
13414−13424. (f) Shirakawa, S.; Liu, K.; Maruoka, K. Catalytic
Asymmetric Synthesis of Axially Chiral o-Iodoanilides by Phase-
Transfer Catalyzed Alkylations. J. Am. Chem. Soc. 2012, 134, 916−919.
(g) Denmark, S. E.; Weintraub, R. C.; Gould, N. D. J. Effects of
Charge Separation, Effective Concentration, and Aggregate Formation
on the Phase Transfer Catalyzed Alkylation of Phenol. J. Am. Chem.
Soc. 2012, 134, 13415−13429.
(3) (a) Crossley, S.; Faria, J.; Shen, M.; Resasco, D. E. Solid
Nanoparticles that Catalyze Biofuel Upgrade Reactions at the Water/
Oil Interface. Science 2010, 327, 68−72. (b) Dinsmore, A. D.; Hsu, M.
F.; Nikolaides, M. G.; Marquez, M.; Bausch, A. R.; Weitz, D. A.
Colloidosomes: Selectively Permeable Capsules Composed Colloidal
Particles. Science 2002, 298, 1006−1009. (c) Whitesides, G. M.;
Grzybowski, B. Self-Assembly at All Scales. Science 2002, 295, 2418−
2421.
(4) Wang, J.-C.; Ma, J.-P.; Liu, Q.-K.; Dong, Y.-B. Cd(II)-MOF-IM:
Post-Synthesis Functionalization of Cd(II)-MOF for Triphase Trans-
fer Catalyst. Chem. Commun. 2016, 52, 6989−6992.
(5) Ding, L.-G.; Yao, B.-J.; Jiang, W.-L.; Li, J.-T.; Fu, Q.-J.; Li, Y.-A.;
Liu, Z.-H.; Ma, J.-P.; Dong, Y.-B. Bifunctional Imidazolium-Based
Ionic Liquid Decorated UiO-67 Type MOF for Selective CO2
Adsorption and Catalytic Property for CO2 Cycloaddition with
Epoxides. Inorg. Chem. 2017, 56, 2337−2344.
(6) (a) Dhakshinamoorthy, A.; Garcia, H. Chem. Soc. Rev. 2012, 41,
5262−5284. (b) Moon, H. R.; Lim, D.-W.; Suh, M. P. Fabrication of
Metal Nanoparticles in Metal-Organic Frameworks. Chem. Soc. Rev.
2013, 42, 1807−1824.
MOF-based catalysts for one-pot CuAAC has been reported,
but with organic solvent in N2 atmosphere.14e
CONCLUSION
■
In summary, a facile and practical sequential one-pot catalytic
method for the generation of 1,4-disubstituted triazoles from
halogenated compounds and sodium azide has been developed.
It is different from most previous reports in that the one-pot
reactions catalyzed by the bifunctional solid catalyst of 2 herein
have a certain “greenness” to them, involving a water medium,
air atmosphere, and catalyst reutilization. We expect this
approach to be viable for the construction of many more new
and practical multifunctional composite heterogeneous catalytic
systems for green organic synthesis, and studies toward the
preparation of new heterogeneous catalysts of this type
containing other MOF supports and/or metal species are
underway.
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.inorg-
chem.7b01025.
■
S
Synthesis and characterization of L; characterization of
azidated products (for Table 2); “click” reaction products
(for Table 4); one-pot CuAAC products (for Table 5)
(PDF)
AUTHOR INFORMATION
Corresponding Author
*E-mail: yubindong@sdnu.edu.cn.
■
ORCID
Yu-Bin Dong: 0000-0002-9698-8863
(7) Some recent articles related to active catalytic species loaded
MOF catalysts for the heterogeneous tandem catalysis: (a) Manna, K.;
Zhang, T.; Greene, F. X.; Lin, W. Bipyridine- and Phenanthroline-
Based Metal−Organic Frameworks for Highly Efficient and Tandem
Catalytic Organic Transformations via Directed C−H Activation. J.
Am. Chem. Soc. 2015, 137, 2665−2673. (b) Verde-Sesto, E.; Merino,
Author Contributions
†Y.-H.H and J.-C.W. contributed equally.
Notes
The authors declare no competing financial interest.
́
E.; Rangel-Rangel, E.; Corma, A.; Iglesias, M.; Sanchez, F.
ACKNOWLEDGMENTS
■
Postfunctionalized Porous Polymeric Aromatic Frameworks with an
Organocatalyst and a Transition Metal Catalyst for Tandem
Condensation−Hydrogenation Reactions. ACS Sustainable Chem.
Eng. 2016, 4, 1078−1084. (c) Beyzavi, M. H.; Vermeulen, N. A.;
Howarth, A. J.; Tussupbayev, S.; League, A. B.; Schweitzer, N. M.;
Gallagher, J. R.; Platero-Prats, A. E.; Hafezi, J. F.; Sarjeant, N.; Miller,
A. A.; Chapman, J. T.; Stoddart, K. W.; Cramer, C. J.; Hupp, J. T.;
Farha, O. K. A Hafnium-Based Metal−Organic Framework as a
Nature-Inspired Tandem Reaction Catalyst. J. Am. Chem. Soc. 2015,
137, 13624−13631. (d) Dau, P. V.; Cohen, S. M. A Bifunctional, Site-
Isolated Metal−Organic Framework-Based Tandem Catalyst. Inorg.
Chem. 2015, 54, 3134−3138. (e) Wang, J.-S.; Jin, F.-Z.; Ma, H.-C.; Li,
X.-B.; Liu, M.-Y.; Kan, J.-L.; Chen, G.-J.; Dong, Y.-B. Au@Cu(II)-
MOF: Highly Efficient Bifunctional Heterogeneous Catalyst for
Successive Oxidation-Condensation Reactions. Inorg. Chem. 2016,
55, 6685−6691. (f) Li, Y.-A.; Yang, S.; Liu, Q.-K.; Chen, G.-J.; Ma, J.-
P.; Dong, Y.-B. Pd(0)@UiO-68-AP: Chelating-Directed Bifunctional
Heterogeneous Catalyst for Stepwise Organic Transformations. Chem.
Commun. 2016, 52, 6517−6520. (g) Yang, Q.; Chen, Y.-Z.; Wang, Z.
U.; Xu, Q.; Jiang, H.-L. One-Pot Tandem Catalysis over Pd@MIL-
101: Boosting the Efficiency of Nitro Compound Hydrogenation by
Coupling with Ammonia Borane Dehydrogenation. Chem. Commun.
2015, 51, 10419−10422. (h) Yang, Q.; Xu, Q.; Yu, S.-H.; Jiang, H.-L.
Pd Nanocubes@ZIF-8: Integration of Plasmon-Driven Photothermal
Conversion with a Metal−Organic Framework for Efficient and
We are grateful for financial support from NSFC (Grant Nos.
21671122 and 21475078), the 973 Program (Grant No.
2013CB933800), and the Taishan scholar’s construction
project.
REFERENCES
■
(1) (a) Starks, C. M. Phase-transfer catalysis. I. Heterogeneous
reactions involving anion transfer by quaternary ammonium and
phosphonium salts. J. Am. Chem. Soc. 1971, 93, 195−199. (b) Maruoka,
K.; Ooi, T. Enantioselective Amino Acid Synthesis by Chiral Phase-
Transfer Catalysis. Chem. Rev. 2003, 103, 3013−3028. (c) Dupont, J.;
de Souza, R. F.; Suarez, P. A. Z. Enantioselective Amino Acid Synthesis
by Chiral Phase-Transfer Catalysis. Chem. Rev. 2002, 102, 3667−3692.
(d) Tan, J.; Yasuda, N. Contemporary Asymmetric Phase Transfer
Catalysis: Large-Scale Industrial Applications. Org. Process Res. Dev.
2015, 19, 1731−1746. (e) Maruoka, K. Practical Aspects of Recent
Asymmetric Phase-Transfer Catalysis. Org. Process Res. Dev. 2008, 12,
679−697.
(2) (a) Uyanik, M.; Okamoto, H.; Yasui, T.; Ishihara, K. Quaternary
Ammonium (Hypo)iodite Catalysis for Enantioselective Oxidative
Cycloetherification. Science 2010, 328, 1376−1379. (b) Uyanik, M.;
Hayashi, H.; Ishihara, K. High-Turnover Hypoiodite Catalysis for
Asymmetric Synthesis of Tocopherols. Science 2014, 345, 291−294.
(c) Rauniyar, V.; Lackner, A.; Hamilton, G. L.; Toste, F. D.
F
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Selective Catalysis. Angew. Chem., Int. Ed. 2016, 55, 3685−3689.
(i) Chen, Y.-Z.; Zhou, Y.-X.; Wang, H.; Lu, J.; Uchida, T.; Xu, Q.; Yu,
S.-H.; Jiang, H.-L. Multifunctional PdAg@MIL-101 for One-Pot
Cascade Reactions: Combination of Host−Guest Cooperation and
Bimetallic Synergy in Catalysis. ACS Catal. 2015, 5, 2062−2069.
(j) Zhu, N.-X.; Zhao, C.-W.; Wang, J.-C.; Li, Y.-A.; Dong, Y.-B. Micro-
Cu4I4-MOF: Reversible Iodine Adsorption and Catalytic Properties
for Tandem Reaction of Friedel−Crafts Alkylation of Indoles with
Acetals. Chem. Commun. 2016, 52, 12702−12705. (k) Chen, G.-J.; Ma,
H.-C.; Xin, W.-L.; Li, X.-B.; Jin, F.-Z.; Wang, J.-S.; Liu, M.-Y.; Dong,
Y.-B. Dual Heterogeneous Catalyst Pd-Au@Mn(II)-MOF for One-Pot
Tandem Synthesis of Imines from Alcohols and Amines. Inorg. Chem.
2017, 56, 654−660. (l) Dong, Y.; Li, Y.; Wei, Y.-L.; Wang, J.-C.; Ma,
J.-P.; Ji, J.; Yao, B.-J.; Dong, Y.-B. N-Heterocyclic Tetracarbene Pd(II)
Moiety Containing Pd(II)/Pb(II) Bimetallic MOF for Three-
Component Cyclotrimerization via Benzyne. Chem. Commun. 2016,
52, 10505−10508.
(8) (a) Schaate, A.; Roy, P.; Godt, A.; Lippke, J.; Waltz, F.; Wiebcke,
M.; Behrens, P. Modulated Synthesis of Zr-Based Metal−Organic
Frameworks: From Nano to Single Crystals. Chem. - Eur. J. 2011, 17,
6643−6651. (b) Li, Y.-A.; Zhao, X.-D.; Yin, H.-P.; Yang, S.; Chen, G.-
J.; Dong, Y.-B. Drug-Loaded Nanoscale Metal-Organic Framework
with Tumor Targeting Agent for Highly Effective Hepatomatherapy.
Chem. Commun. 2016, 52, 14113−14116.
(9) (a) Meldal, M.; Tornøe, C. W. Cu-Catalyzed Azide−Alkyne
Cycloaddition. Chem. Rev. 2008, 108, 2952−3015.
(10) Wang, B.; Huang, H. L.; Lv, X. L.; Xie, Y. B.; Li, M.; Li, J. R.
Tuning CO2 Selective Adsorption over N2 and CH4 in UiO-67
Analogues through Ligand Functionalization. Inorg. Chem. 2014, 53,
9254−9259.
(11) Ma, J.-P.; Wang, S.-Q.; Zhao, C.-W.; Yu, Y.; Dong, Y.-B. Cu(II)-
Metal−Organic Framework with Open Coordination Metal Sites for
Low Temperature Thermochemical Water Oxidation. Chem. Mater.
2015, 27, 3805−3808.
̀
(12) Garzon-Tovar, L.; Rodríguez-Hermida, S.; Imaz, I.; Maspoch, D.
Spray Drying for Making Covalent Chemistry: Postsynthetic
Modification of Metal−Organic Frameworks. J. Am. Chem. Soc.
2017, 139, 897−903.
(13) Zhu, W.; Ma, D.-W. Synthesis of aryl azides and vinyl azides via
proline-promoted CuI-catalyzed coupling reactions. Chem. Commun.
2004, 7, 888−889.
(14) Recent articles for one-pot CuAAC: (a) Kumar, K.; Konar, D.;
Goyal, S.; Gangar, M.; Chouhan, M.; Rawal, R. K.; Nair, V. A. Water-
Promoted Regiospecific Azidolysis and Copper-Catalyzed Azide−
Alkyne Cycloaddition: One-Pot Synthesis of 3-Hydroxy-1-alkyl-3-[(4-
aryl/alkyl-1H-1,2,3-triazol-1-yl)methyl]indolin-2-ones. J. Org. Chem.
2016, 81, 9757−9764. (b) Liu, M.; Reiser, O. A Copper(I) Isonitrile
Complex as a Heterogeneous Catalyst for Azide-Alkyne Cycloaddition
in Water. Org. Lett. 2011, 13, 1102−1105. (c) Li, F.; Andy Hor, T. S.
Facile Synthesis of Nitrogen Tetradentate Ligands and Their
Applications in CuI-Catalyzed N-Arylation and Azide-Alkyne Cyclo-
addition. Chem. - Eur. J. 2009, 15, 10585−10592. (d) Beckmann, H. S.
G.; Wittmann, V. One-Pot Procedure for Diazo Transfer and Azide−
Alkyne Cycloaddition: Triazole Linkages from Amines. Org. Lett.
́
2007, 9, 1−4. (e) Luz, I.; Liabres i Xamena, F. X.; Corma, A. Bridging
Homogeneous and Heterogeneous Catalysis with MOFs: “Click”
Reaction with Cu-MOF Catalysts. J. Catal. 2010, 276, 134−140.
G
DOI: 10.1021/acs.inorgchem.7b01025
Inorg. Chem. XXXX, XXX, XXX−XXX