Pd@UiO-66: An Efficient Catalyst for Suzuki-Miyaura Coupling Reaction at Mild Condition

Article abstract of DOI:10.1007/s10562-015-1659-4

In this paper, the palladium nanoparticles were successfully encapsulated in metal-organic framework material, UiO-66, by a facile approach. Based on the microwave-assisted method, the pores of UiO-66 were activated and the metal precursors were reduced at the same time in the presence of reducing agent. The obtained Pd@UiO-66 was characterized via transmission electron microscopy, powder X-ray diffraction, N₂ adsorption and X-ray photoelectron spectroscopy. The Pd@UiO-66 exhibited efficient catalytic activity for the Suzuki-Miyaura coupling reactions at mild condition. Graphical Abstract: The palladium nanoparticles were successfully encapsulated in metal-organic framework material, UiO-66, by a facile approach. Based on the microwave-assisted method, the pores of UiO-66 were activated and the metal precursors were reduced at the same time in the presence of reducing agent. The obtained Pd@UiO-66 exhibited efficient catalytic activity for the Suzuki-Miyaura coupling reactions at mild condition.]

Full text of DOI:10.1007/s10562-015-1659-4

Catal Lett
DOI 10.1007/s10562-015-1659-4
Pd@UiO-66: An Efficient Catalyst for Suzuki–Miyaura Coupling
Reaction at Mild Condition
Wenhuan Dong1 Cheng Feng1 Li Zhang1 Ningzhao Shang1 Shutao Gao1
•
•
•
•
•
Chun Wang1 Zhi Wang1
•
Received: 29 July 2015 / Accepted: 13 November 2015
Ó Springer Science+Business Media New York 2015
Abstract In this paper, the palladium nanoparticles were
successfully encapsulated in metal–organic framework
material, UiO-66, by a facile approach. Based on the
microwave-assisted method, the pores of UiO-66 were
activated and the metal precursors were reduced at the
same time in the presence of reducing agent. The obtained
Pd@UiO-66 was characterized via transmission electron
microscopy, powder X-ray diffraction, N2 adsorption and
X-ray photoelectron spectroscopy. The Pd@UiO-66
exhibited efficient catalytic activity for the Suzuki–
Miyaura coupling reactions at mild condition.
Graphical Abstract The palladium nanoparticles were
successfully encapsulated in metal–organic framework
material, UiO-66, by a facile approach. Based on the
microwave-assisted method, the pores of UiO-66 were
activated and the metal precursors were reduced at the
same time in the presence of reducing agent. The obtained
Pd@UiO-66 exhibited efficient catalytic activity for the
Suzuki–Miyaura coupling reactions at mild condition.
O
O
Zr
Pd(0)
ZrCl4, DMF, HCl
H2PdCl4
microwave
O
O
UiO-66
Pd@UiO-66
Keywords Microwave Á Palladium nanoparticle Á Metal–
organic frameworks Á Suzuki–Miyaura coupling reaction
1 Introduction
Palladium-catalyzed Suzuki–Miyaura coupling reaction is
one of the most powerful methods to constructing biaryl
units in organic synthesis [1–4]. Based on palladium,
homogeneous catalytic system has played a significant role
in organometallic catalysis [5]. However, homogeneous
catalyst suffers from instability, non-reusability, difficulty
to separate from the reaction system. Hence, to develop Pd
& Chun Wang
chunwang69@126.com
1
College of Science, Agricultural University of Hebei,
Baoding 071001, Hebei, China
123

W. Dong et al.
catalyst with excellent recyclability and reusability has the
great significance in sustainability development and pro-
tecting the environment. In order to achieve this task,
heterogeneous catalytic system has been employed in
recent years. A number of materials have been used to
support the Pd nanoparticles (NPs), such as silica, zeolites,
carbon or covalent organic polymers, for the carbon–car-
bon coupling reactions. Nevertheless, above materials have
some limitations such as low stability and catalytic effi-
ciency. Therefore, it is essential to explore an efficient
heterogeneous palladium catalytic system for the coupling
reaction.
atoms was packed in them. The highly thermal stability
could be attributed to the highly symmetrical inorganic
metal units and the strong interaction force between the
Zr6-octahedron with the oxygen atoms. The Zr-based MOF
has been synthesized by Lillerud and his co-workers via a
conventional solvothermal method [27]. However, the
traditional heating methods for the preparation of UiO-66
always need many hours or even several days in the syn-
thesis process, which is not desirable for industrial
applications.
Microwave-assisted synthesis as a relatively novel
method has found lots of applications in various chemical
transformations, including the synthesis of nanoporous
materials. The fabrication of MOFs under microwave
irradiation not only largely reduce the reaction time, but
also can control the size and shape of the crystals [28].
Recently, the microwave-assisted technique has been
widely applied as an alternative method in the synthesis of
organic–inorganic hybrid materials including MOFs [29–
32]. Recently, UiO-66 was synthesized efficiently with a
high yield in the presence of an additive (benzoic acid and
acetic acid) using microwave irradiation. The result indi-
cated that the microwave irradiation could not only shorten
the reaction time, but also improve the surface area of UiO-
66. At the same time, the product using microwave irra-
diation has shown excellent adsorption ability for dyes
[33].
Metal–organic frameworks (MOFs) have emerged as a
novel class of functional materials due to their high surface
areas, tunable pore sizes, and thermal stability. Owing to
these outstanding properties, MOFs have been employed in
gas storage [6, 7], catalysis [8, 9], adsorption [10, 11],
super-capacitor [12], and drug delivery [13]. In recent
years, the employment of MOFs as the supports for Pd NPs
has attracted considerable interest [8, 14–17]. Gao et al.
[18] used immersion method to prepare Pd@MOF-5 and
applied to catalyze coupling reactions. Meike [19] and his
co-workers synthesized MIL-53-NH2 (Al) by a two-step
post-synthetic method and the obtained Pd-containing
MOFs exhibited high conversion and selectivity in carbon–
carbon coupling reactions. Pd@MIL-101 was prepared by
us using a ‘‘double solvents’’ method, this method could
effectively avoid the aggregation of palladium nanoparti-
cles on the external surfaces of MIL-101. So the catalyst
could be readily recovered and reused in at least 5 con-
secutive cycles without significant loss its catalytic activity
in Suzuki–Miyaura and Heck cross-coupling reactions
[20].
Herein, we successfully synthesized UiO-66 by a
microwave-assisted method and which was employed as a
support for Pd nanoparticles. To evaluate the performance
of the obtained catalyst, Pd@UiO-66, Suzuki–Miyaura
cross-coupling reaction was selected as the model reac-
tion. The results demonstrated that Pd@UiO-66 can cat-
alyze the Suzuki coupling reaction efficiently even at mild
condition.
UiO-66, a Zr-based MOF, has outstanding physical and
chemical properties, such as large specific area and pore
size as well as good chemical resistance to water and
organic solvents, which make UiO-66 become a highly
desirable and most promising material for catalytic appli-
cations [21–24]. Recently, Pd@UiO-66 was fabricated by
chemical vapor infiltration of (allyl)Pd(Cp) followed by
UV light irradiation, which was used as shape-selective
hydrogenation catalyst [25]. Tangestaninejad et al. pre-
pared a heterogeneous catalyst, Pd@UiO-66-NH2, using a
direct anionic exchange method followed by chemical
reduction with sodium acetate in methanol. Pd@UiO-66-
NH2 was applied for catalyzing the Suzukie–Miyaura
cross-coupling reaction [16]. Bifunctional Zr-MOF catalyst
containing palladium nanoclusters, Pd@UiO-66-NH2, has
been developed and exhibited high catalytic activity and
selectivity in a one-pot tandem oxidation-acetalization
reaction [26]. The molecular formulas of UiO-66 has been
demonstrated of Zr6O4(OH)4(CO2)12, and it has the highest
coordination in MOFs of 12-coordination and the metal
2 Experiment
2.1 Materials
All chemicals were commercial and used without further
purification. Zirconium chloride (ZrCl4, 96 %), 1,4-ben-
zenedicarboxylate (BDC, 99 %), palladium chloride
(PdCl2), aryl halides, arylboronic acids were obtained from
Aladdin Reagent Limited Company. Sodium borohydride
(NaBH4, 99 %), potassium carbonate (K2CO3), N,N-
dimethylformamide (DMF), anhydrous ethanol (EtOH)
were acquired from Chengxin Chemical Reagent Company
(Baoding, China).
The X-ray diffraction (XRD) patterns of UiO-66 and
Pd@UiO-66 were recorded by Dandong TD-3500 X-ray
diffractometer at 40 kV and 150 mA with Cu Ka
123

Pd@UiO-66: An Efficient Catalyst for Suzuki–Miyaura Coupling Reaction at Mild Condition
irradiation. The transmission electron microscopy (TEM)
images were observed by FEI Tecnai f20 at 200 kV and the
samples were dispersed under the ultrasonic. The image of
X-ray photoelectron spectroscopy (XPS) was obtained by
Thermo ESCALAB 250Xi using a monochromatic Al Ka
source at 1486.6 eV. The Brunauer–Emmett–Teller (BET)
surface areas of the samples were measured using V-Sorb
2800 at 77 K and dealt at 100 °C for 4 h in vacuum before
the nitrogen adsorption and desorption. The catalyst was
synthesized by XH-100B at 700 W. The Pd content of the
solution after reaction was determined by means of
inductively coupled plasma atomic emission spectroscopy
(ICP-AES) on Thermo Elemental IRIS Intrepid II.
v/v) and Pd@UiO-66 (2 mg, 0.075 mol%) were added to a
round-bottom flask. The mixture was stirred at room tem-
perature for the appropriate time in air. After that, the
reaction mixture was diluted with 10 mL of H2O and
extract with ethyl acetate (3 9 10 mL). Then, the organic
layer was combined, dried over anhydrous MgSO4 and
filtered. Solvent was removed under vacuum, and the
reaction products were purified by flash chromatography on
silica gel with petroleum ether/ethyl acetate as the eluent.
In the recyclability experiment, the reaction of bro-
mobezene and phenylboronic acid was chosen as a model
reaction.
A mixture of bromobenzene (0.5 mmol),
phenylboronic acid (0.6 mmol), potassium carbonate
(1.5 mmol), EtOH–H2O (4 mL, 1;1, v/v) and Pd@UiO-66
(2 mg, 0.075 mol%) was stirred at room temperature for
30 min, then the catalyst was separated by centrifugation
and dryed in vacuum at 60 °C. The conditions of the
recycling reactions were same as describe above, except of
using the recovered catalyst.
2.2 Synthesis of UiO-66 and Pd@UiO-66
The UiO-66 was prepared according to the procedure
reported by Michael [34]. ZrCl4 (500 mg, 2.16 mmol) was
dispersed in HCl (4 mL)/DMF (20 mL) to give a clear
solution under ultrasonic. Then, 1,4-benzenedicarboxylate
(BDC) (492 mg, 3 mmol) dispersed in 40 mL DMF was
added into the above solution. Finally, the mixed solution
was placed into the microwave oven and irradiated at
100 °C for 2 h. After centrifugation, the obtained UiO-66
was washed two times with water and dried in vacuum at
150 °C overnight.
UiO-66 (100 mg) was dispersed in water (5 mL) and then
the H2PdCl4 (3.334 mL, 1 mg/mL) was added to it. Then the
mixture was stirred for 24 h at room temperature and the
solid was separated by centrifugation to get rid of the
unnecessary metal ions from the solution. The obtained solid
was redispersed in water and NaBH4 (7.5 mg) was added in it
under stirring. Then, the mixture was placed into the micro-
wave oven and irradiated at 30 °C for 20 min. Finally, the
product, Pd@UiO-66, was centrifuged, washed with deion-
ized water and dried in vacuum at 60 °C overnight (Fig. 1).
2.3.1 Hot Filtration Test
In the hot filtration test, a mixture of bromobenzene
(0.5 mmol), phenylboronic acid (0.6 mmol), potassium
carbonate (1.5 mmol), EtOH–H2O (4 mL, 1:1, v/v) and the
catalyst Pd@UiO-66 (2 mg, 0.075 mol%) was stirred at
room temperature. After 15 min, the catalyst was separated
by centrifugation, the reaction solution was stirred still for
30 min, and the progress of the reaction was examined by
flash chromatography on silica gel with petroleum ether/
ethyl acetate as the eluent.
3 Results and Discussion
3.1 Characterization of the Catalyst
2.3 General Procedure for Suzuki–Miyaura
Reaction
The TEM images of Pd@UiO-66 were shown in Fig. 2, the
Pd nanoparticles were dispersed over the UiO-66 uni-
formly. It can be seen that the Pd nanoparticles were
obtained with a narrow particle size about 5 nm. Energy
dispersive X-ray spectroscopy (EDX) was shown in Fig. 3,
Typically, aryl halide (0.5 mmol), phenylboronic acid
(0.6 mmol), alkali (1.5 mmol), EtOH–H2O (4 mL, 1:1,
Fig. 1 Schematic illustration of
the synthetic process of
Pd@UiO-66
O
O
Zr
Pd(0)
ZrCl4, DMF, HCl
H2PdCl4
microwave
O
O
UiO-66
Pd@UiO-66
123

W. Dong et al.
Fig. 2 a and b TEM images of fresh Pd@UiO-66, c and d reused catalyst
which further confirm the existence of the Pd. The palla-
dium concentration in Pd@UiO-66 was determined by
means of ICP-AES and amounted to 2.5 wt%.
XRD patterns of UiO-66 and Pd@UiO-66 were shown
in Fig. 4. It can be seen that the samples of UiO-66 have
the sharp peaks, which are matched with the previous
report [35], which indicated that the sample of UiO-66 has
the excellent crystallinity. As shown in Fig. 4, the
diffraction peaks of Pd@UiO-66 are similar to those of
UiO-66, indicating that Pd@UiO-66 exhibit no loss of
crystallinity upon metal coordination. Moreover, Fig. 4 has
not shown the diffraction peak characteristic of Pd NPs,
which can be ascribed to the low amount of Pd NPs, the
encapsulated of Pd nanoparticles into the pores of UiO-66,
low Pd loading and well dispersed Pd NPs. The result is
consistent with the results reported in the document [36].
To further confirm the presence of Pd nanoparticles in the
sample, we performed XPS analysis for Pd@UiO-66. In
Fig. 5a, the peaks of C, O, Zr, and Pd could be clearly seen,
nevertheless, Pd expresses weak peak relatively, it is
Fig. 3 The EDX pattern of Pd@UiO-66
possible that the low content Pd was introduced in. After
the deconvolution, the Pd 3d spectrum is exhibited in
Fig. 5b, the characteristic peaks of Pd 3d3/2 and Pd 3d5/2
123

Pd@UiO-66: An Efficient Catalyst for Suzuki–Miyaura Coupling Reaction at Mild Condition
500
UiO-66
fresh Pd@UiO-66
400
UiO-66
Resued Pd@UiO-66
300
Pd@UiO-66
200
100
0
0.0
0.2
0.4
0.6
0.8
1.0
P/P0
10
20
30
40
50
60
Two theta (degree)
Fig. 6 N2 adsorption of UiO-66 andPd@UiO-66
Fig. 4 XRD patterns for UiO-66, fresh Pd@UiO-66 and reused
Pd@UiO-66
N2 adsorption experiments of UiO-66 and Pd@UiO-66
are tested at 77 K, the results are shown in Fig. 6. The BET
surface areas of UiO-66 and Pd@UiO-66 are 1129.8 and
895.9 m2/g, respectively. And 0.6346 and 0.4864 cm3/g are
are showed at 340.88 and 335.42 eV, respectively, which
demonstrated that the Pd species in the Pd@UiO-66 was
present in the metallic state.
(a)
(c)
1000
800
600
400
200
1000
800
600
400
200
Binding Energy (eV)
Binding Energy (eV)
(b)
(d)
Zr 3p1/2
Pd 3d3/2
Pd3d5/2
Zr 3p3/2
Zr 3p1/2
Pd 3d3/2
Pd 3d5/2
Zr 3p3/2
350 348 346 344 342 340 338 336 334 332 330
Binding Energy (eV)
350 348 346 344 342 340 338 336 334 332 330
Binding Energy (eV)
Fig. 5 XPS images of Pd@UiO-66 (a and b) and the reused catalyst (c and d)
123

W. Dong et al.
Yield (%)
Table 1 Optimization of
influence factors for the Suzuki–
Miyaura reaction of
bromobenzene with
phenylboronic acid
Entry
Catalyst
Solvents
Bases
Pd (mol%)
Time (min)
1
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
Pd@UiO-66
UiO-66
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
–
0.1
40
40
40
10
20
30
60
30
30
30
30
30
30
30
30
30
30
15
30
95
94
73
30
50
93
95
–
2
0.075
0.05
3
4
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
0.075
5
6
7
8
9
Na2CO3
Et3N
74
14
18
15
15
37
58
2
10
11
12
13
14
15
16
17
18
19
NaAc
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
H2O
EtOH–H2O(3:1)
EtOH–H2O(1:3)
DMF
EtOH–H2O(1:1)
EtOH–H2O(1:1)
EtOH–H2O(1:1)
–
Pd@UiO-66
Pd@UiO-66
39
42a
Reaction conditions: bromobenzene (0.5 mmol), phenylboronic acid (0.75 mmol), base (1.5 mmol), sol-
vent (4 mL), 30 °C
a
The catalyst was removed after 15 min, the filtrate was stirred still for 30 min
the total pore volume of UiO-66 and Pd@UiO-66,
respectively. The decreasing of BET and pore volume
indicate that the interspace of UiO-66 was occupied by Pd
nanoparticles.
Further experiments showed that the yield of the product
increased from 30 to 93 % (Table 1, entries 4–6) with
increasing the reaction time from 10 min to 30 min. When
the reaction time was larger than 30 min, the yield of
biphenyl no longer increased greatly (Table 1, entries 2, 7).
The type of base used in Suzuki coupling reaction greatly
affects the reaction efficiency. Some typical bases including
Et3N, NaAc, Na2CO3 and K2CO3 were investigated
(Table 1, entries 6, 8–11). The results showed that good
yield was obtained when K2CO3 was used as the base. The
yield of the product using K2CO3 as the base was higher than
that using Na2CO3, which is probably related to the sizes of
the metal cations. Potassium ion with a relatively larger size
has a weaker ion-pairing interaction than sodium, which
would lead to its higher solubility in the solvent and higher
basicity [17]. The type of reaction media were also inves-
tigated, the excellent yield was obtained with EtOH–H2O
(4 mL, 1:1, v/v) as the solvent (entries 6, 12–16).
3.2 Suzuki–Miyaura Reactions Catalyzed
by the Prepared Catalyst
To investigate the catalytic activity of Pd@UiO-66,
Suzuki–Miyaura cross-coupling reaction was selected as
the model reaction. In the initial experiment of Suzuki–
Miyaura reaction, the coupling reaction of phenyl bromide
and phenylboronic acid was chosen. The results indicated
that Pd@UiO-66 exhibited high catalytic activity for the
coupling reaction at mild condition (30 °C). Different
reaction conditions that effect the reaction efficiency, such
as molar ratio of reactant, reaction time, types of base and
solvent, were investigated in detail. The results were shown
in Table 1.
The catalytic activity of Pd@UiO-66 for Suzuki reac-
tions was investigated with various aryl halides and aryl-
boronic acids. Those reactions were conducted in the
presence of K2CO3 using EtOH–H2O (1:1, v/v) as envi-
ronmental friendly solvent. It is well known that the yields
of the coupling reactions depend on the type of halide
element, the positions of the substitutional groups and their
electron withdrawing/donating capabilities. As can be seen
from Table 2, good yields were obtained in the reactions of
In the initial experiments, the reaction time was set at
40 min, the yields of biphenyl increased from 73 to 95 %
when the dosage of Pd@UiO-66 was adjusted from 0.05 to
0.1 mol% (Table 1, entries 1–3). 0.075 mol% amount of
Pd@UiO-66 was sufficient to guarantee complete conver-
sion. The reaction does not take place in the absent of
catalyst, which indicated that the catalyst play a key role
for the coupling reaction.
123

Pd@UiO-66: An Efficient Catalyst for Suzuki–Miyaura Coupling Reaction at Mild Condition
Table 2 Pd@UiO-66-catalyzed Suzuki coupling reactions
Entry
1
Ary halides
Arylboronic acids Time/h
Products
Yield/%
96
I
B(OH)2
B(OH)2
0.5
1
Br
CH3
Br
2
3
95
88
CH3
B(OH)2
1.5
H3C
O2N
Br
Br
B(OH)2
B(OH)2
CH3
NO2
4
5
1.5
1
92
93
H3C
H3C
H3C
H3C
CH3
Br
6
1
96
97
99
99
78
B(OH)2
CH3 CH3
CH3
Br
7
1.5
1.5
1
B(OH)2
B(OH)2
B(OH)2
H3C
H3C
O2N
Br
Br
Br
8
H3C
O2N
H3C
CH3
9
CH3
B(OH)2
10
1
CH3
CH3
B(OH)2
O2N
Br
11
12
1
6
96
29
O2N
Cl
B(OH)2
Reaction conditions: Aryl bromide (0.5 mmol), phenylboronic acid (0.75 mmol), alkali (1.5 mmol), EtOH–H2O (1:1, 4 mL) and Pd@UiO-66
(0.075 mol%), 30 °C
aryl iodides and less reactive bromobenzene with phenyl-
boronic acid (Table 2, entries 1–11) at ambient tempera-
ture. For most of the substrates, the reaction could be
completed in 0.5–1.5 h with moderate or excellent yields,
with the substrates having either electron-donating groups
or electron-withdrawing groups. It is worth to noted that
2-methyl bromobenzene (Table 2, entry 3) and 2-methyl
arylboronic acid (Table 2, entries 10, 11), which were
influenced by steric hindrance, the coupling reactions could
also proceeded well. Unfortunately, for the reaction of
inactive aryl chlorides (Table 2, entry 12), the yield is only
29 % even when the reaction time was 6 h because of the
C–Cl bond is more powerful than C–Br and C–I bond.
To confirm the heterogeneity of the catalyst, a hot fil-
tration experiment was performed with the reaction of
bromobenzene and phenylboronic acid. After 15 min, the
catalyst was separated by centrifugation and the reaction
solution was stirred still for 30 min. The result indicated
that there was no further conversion after the removal of
the catalyst (Table 1, entries 18, 19). The absence of pal-
ladium ions in the solution after reaction was also con-
firmed by the inductively coupled plasma atomic emission
spectroscopy analysis.
To evaluate the efficiency of the catalyst for Suzuki
coupling reaction, TOF and yield has been calculated for
comparison with that of other reported Pd catalyst. The
data in Table 3 showed that the Pd@UiO-66 using
microwave assisted exhibited efficiently catalytic activity
at mild condition without using toxic organic solvent.
The recyclability of Pd@UiO-66 was studied because
the recycling of the heterogeneous catalyst plays a key role
in practical applications. The heterogeneous catalyst,
Pd@UiO-66, can be separated easily via filtration. The
Suzuki coupling reaction between bromobenzene and
123

W. Dong et al.
Table 3 Suzuki coupling reaction of bromobenzene with phenylboronoic acid by different catalysts
Catalyst
Dosage (mol%)
T/oC
Recycling times
Yield (%)
TOF/h-1
Refs
Pd@MOF-253
0.23
0.25
3
100
60
5
5
90–94
90
29.8–43.5
623.3–699.2
63.3–66.7
129.5–131.3
108000
[17]
Pd@UiO-66-NH2
Pd@MIL-101-NH2
Pd@H2P-Bph-COF
Pd@Graphene
[16]
23
10
5
84–99
97–99
100
[37]
0.5
110
[38]
0.3
80 (MWI)
80 (MWI)
30
10
10
5
[39]
Pd@Fe3O4-Graphene
Pd@Uio-66(MW)
0.3
100
111000
[40]
0.075
95
1266.7
This study
conditions. The catalyst can be recycled and reused easily
without significant loss of its catalytic activity. The present
study might highlight the development of high perfor-
mance heterogeneous catalysts by using microwave-as-
sisted method.
100
80
60
Acknowledgments This work was financially supported by the
National Natural Science Foundation of China (Nos. 31171698,
31471643), the Innovation Research Program of Department of
Education of Hebei for Hebei Provincial Universities (LJRC009),
Natural Science Foundation of Hebei Province (B2015204003) and
the Natural Science Foundation of Agricultural University of Hebei
(ZD201506, LG201404).
40
20
0
1
2
3
Run
4
5
References
1. Xiao Q, Sarina S, Jaatinen E, Jia J, Arnold DP, Liu H, Zhu H
(2014) Green Chem 16:4272
Fig. 7 Recyclability of Pd@UiO-66 for Suzuki reaction
2. Martin AD, Siamaki AR, Belecki K, Gupton BF (2015) J Org
Chem 80:1915
3. Shendage SS, Patil UB, Nagarkar JM (2013) Tetrahedron Lett
54:3457
4. Zhang L, Feng C, Gao ST, Wang Z, Wang C (2015) Catal
Commun 61:21
5. Ma Y, Ma X, Wang Q, Zhou J (2012) Catal. Sci. Technol 2:1879
6. Kaye SS, Dailly A, Yaghi OM, Long JR (2007) J Am Chem Soc
129:14176
7. Hu YH, Zhang L (2010) Adv Mater 22:117
8. Puthiaraj P, Ahn WS (2015) Catal Commun 65:91
9. Phan NTS, Nguyen TT, Nguyen CV, Nguyen TT (2013) Appl
Catal A 457:69
10. Lin S, Song Z, Che G, Ren A, Li P, Liu C, Zhang J (2014)
Microporous Mesoporous Mater 193:27
11. Huang XX, Qiu LG, Zhang W, Yuan YP, Jiang X, Xie AJ, Shen
YH, Zhu JF (2012) CrystEngComm 14:1613
12. Salunkhe RR, Kamachi Y, Torad NL, Hwang SM, Sun Z, Dou
SX, Kim JH, Yamauchi Y (2014) J Mater Chem A 2:19848
13. Taylor-Pashow KML, Rocca JD, Xie Z, Tran S, Lin W (2009) J
Am Chem Soc 131:14261
phenylboronic acid under the optimized reaction conditions
were used for reusability experiments. As can be seen from
Fig. 7, after being recycled for five successive runs,
although the catalyst still exhibits good activity, but the
yields of the product decreased slightly. In order to
research the deactivation mechanism of the catalyst, TEM,
XPS, XRD, and BET analysis were provided for the reused
catalyst. As shown in the XPS (Fig. 5c, d), no changes in
the oxidation states of Pd can be observed in the recycled
catalyst. In the TEM images (Fig. 2c, d), the size of Pd
nanoparticles in the reused catalyst increased and has a
certain degree aggregation. The surface area of the resued
catalyst decreased from 638.6 to 560.6 m2/g. The XRD
characteristic peaks intensity of the reused Pd@UiO-66
decreased (Fig. 4), which could be ascribed to the partial
destruction of the structure of UiO-66.
14. Yuan B, Pan Y, Li Y, Yin B, Jiang H (2010) Angew Chem Int Ed
49:4054
15. Zhang M, Guan J, Zhang B, Su D, Williams CT, Liang C (2012)
Catal Lett 142:313
4 Conclusions
16. Kardanpour R, Tangestaninejad S, Mirkhani V, Moghadam M,
Mohammadpoor-Baltork I, Khosropour AR, Zadehahmadi F
(2014) J Organomet Chem 761:127
17. Chen L, Gao Z, Li Y (2015) Catal Today 245:122
18. Gao S, Zhao N, Shu M, Che S (2010) Appl Catal A 388:196
In conclusion, Pd@UiO-66 was successfully fabricated by
a microwave-assisted method and which exhibited high
catalytic activity for the Suzuki–Miyaura reactions at mild
123

Pd@UiO-66: An Efficient Catalyst for Suzuki–Miyaura Coupling Reaction at Mild Condition
19. Gotthardt MA, Beilmann A, Schoch R, Engelke J, Kleist W
(2013) RSC Adv 3:10676
30. Jung DW, Yang DA, Kim J, Kim J, Ahn WS (2010) Dalton Trans
39:2883
20. Shang NZ, Gao ST, Zhou X, Feng C, Wang Z, Wang C (2014)
RSC Adv 4:54487
31. Wu X, Bao Z, Yuan B, Wang J, Sun Y, Luo H, Deng S (2013)
Microporous Mesoporous Mater 180:114
´
21. Rasero-Almansa AM, Corma A, Iglesias M, Sanchez F (2014)
Green Chem 16:3522
22. Schaate A, Roy P, Godt A, Lippke J, Waltz F, Wiebcke M,
Behrens P (2011) Chem Eur J 17:6643
32. El-Shall MS, Abdelsayed V, Khder AERS, Hassan HMA, El-
Kaderi HM, Reich TE (2009) J Mater Chem 19:7625
33. Li Y, Liu Y, Gao W, Zhang L, Liu W, Lu J, Wang Z, Deng YJ
(2014) CrystEngComm 16:7037
23. Kandiah M, Nilsen MH, Usseglio S, Jakobsen S, Olsbye U, Tilset
M, Larabi C, Quadrelli EA, Bonino F, Lillerud KP (2010) Chem
Mater 22:6632
24. Vermoortele F, Ameloot R, Vimont A, Serre C, Vos DD (2011)
Chem Commun 47:1521
34. Katz MJ, Brown ZJ, Colon YJ, Siu PW, Scheidt KA, Snurr RQ,
Hupp JT, Farha OK (2013) Chem Commun 49:9449
35. Garibay SJ, Cohen SM (2010) Chem Commun 46:7700
36. Shen L, Wu W, Liang R, Lin R, Wu L (2013) Nanoscale 5:9374
37. Pascanu V, Yao Q, Bermejo Gomez A, Gustafsson M, Yun Y,
Wan W, Samain L, Zou X, Martin-Matute B (2013) Chem Eur J
19:17483
25. Luz I, Rosler C, Epp K, Xamena F, Fischer R (2015) Eur J Inorg
Chem 2015:3904
26. Li XL, Guo ZY, Xiao CX, Goh TW, Tesfagaber D, Huang WY
(2014) ACS Catal 4:3490
27. Cavka JH, Jakobsen S, Olsbye U, Guillou N, Lamberti C, Bordiga
S, Lillerud KP (2008) J Am Chem Soc 130:13850
28. Ni Z, Masel RI (2006) J Am Chem Soc 128:12394
29. Son WJ, Kim J, Kim J, Ahn WS (2008) Chem Commun 44:6336
38. Hou Y, Zhang X, Sun J, Lin S, Qi D, Hong R, Li D, Xiao X, Jiang
J (2015) Microporous Mesoporous Mater 214:108
39. Siamaki AR, Khder AERS, Abdelsayed V, El-Shall MS, Gupton
BF (2011) J Catal 279:1
40. Elazab HA, Siamaki AR, Moussa S, Gupton BF, El-Shall MS
(2015) Appl Catal A 491:58
123