Immobilization of a palladium(II) bis(imidazolium) complex onto graphene oxide by noncovalent interactions: an efficient and recyclable catalyst for Suzuki–Miyaura reaction

Article abstract of DOI:10.1007/s13738-017-1253-3

In this research, the Suzuki–Miyaura coupling reaction catalyzed by a palladium(II) complex containing bis(imidazolium) ligand, Pd^II(BIM), immobilized on graphene oxide (GO) as heterogeneous, recyclable and active catalyst is reported. The catalyst, Pd^II(BIM)@GO, was characterized by FT-IR, diffuse reflectance UV–Vis spectroscopy, ICP, field emission scanning electron microscopy, energy-dispersive X-ray analysis, and elemental analysis. It was demonstrated that the GO-supported palladium(II) complex can act as an efficient catalyst and is reusable several times without a significant loss of their catalytic activity.

Full text of DOI:10.1007/s13738-017-1253-3

Journal of the Iranian Chemical Society
https://doi.org/10.1007/s13738-017-1253-3
ORIGINAL PAPER
Immobilization of a palladium(II) bis(imidazolium) complex
onto graphene oxide by noncovalent interactions: an eꢀcient
and recyclable catalyst for Suzuki–Miyaura reaction
1
2
1,2
Majid Moghadam · Hossein Salavati · Zari Pahlevanneshan
Received: 25 April 2017 / Accepted: 17 November 2017
©
Iranian Chemical Society 2017
Abstract
In this research, the Suzuki–Miyaura coupling reaction catalyzed by a palladium(II) complex containing bis(imidazolium)
II
ligand, Pd (BIM), immobilized on graphene oxide (GO) as heterogeneous, recyclable and active catalyst is reported. The
II
catalyst, Pd (BIM)@GO, was characterized by FT-IR, difuse reꢀectance UV–Vis spectroscopy, ICP, ꢁeld emission scanning
electron microscopy, energy-dispersive X-ray analysis, and elemental analysis. It was demonstrated that the GO-supported
palladium(II) complex can act as an eꢂcient catalyst and is reusable several times without a signiꢁcant loss oꢃ their catalytic
activity.
Keywords Heterogeneous catalyst · Graphene oxide · Palladium(II) complex · Suzuki coupling reaction · Aryl halides
Introduction
the immobilization oꢃ catalytically active species ꢃor hetero-
geneous catalysis due to their inertness, large surꢃace area,
stability, and availability [10, 11].
Graphene’s unique hexagonal atomic carbon-layered nano-
structure has attracted an increasing research attention since
its discovery in 2004 [1]. The unusual properties oꢃ these
exꢃoliated graphene sheets, including ꢃast charge mobility
at room temperature, have motivated the generating novel
hybrid materials ꢃor nanoelectronics, photovoltaics, batter-
ies, supercapacitors, and related devices [2–6].
Palladium (Pd)-catalyzed C–C cross-coupling reactions
play a key role in modern organic synthesis [12]. Among
these reactions, Suzuki coupling is the most powerꢃul
method ꢃor the synthesis oꢃ biaryl units which are important
molecular components in pharmaceuticals, herbicides, and
natural products, as well as in engineering materials such as
conducting polymers, molecular wires, and liquid crystals
[13–17]. In these cross-coupling reactions, two molecules
are assembled on the metal via the ꢃormation oꢃ metal–car-
bon bond. The catalytic steps contain oxidative addition,
transmetalation, and reductive elimination [18]. In this way,
the carbon atoms bound to palladium are brought very close
to one another. In the next step, they couple to one another
and this leads to the ꢃormation oꢃ a new carbon–carbon sin-
gle bond.
However, other properties oꢃ graphene such as their large
speciꢁc surꢃace area, unique chemical and thermal stability,
high mechanical strength, chemical versatility and tunability,
and low manuꢃacturing cost represent graphene-based mate-
rials as potential applications in ꢃuel cells, chemical sensors,
hydrogen storage, and heterogeneous catalysis [7–9]. Chemi-
cally derived graphenes such as graphene oxide (GO) and
reduced graphene oxide (rGO) are suitable candidates ꢃor
Applications oꢃ homogenous palladium catalysts in
Suzuki reaction are limited on an industrial scale because oꢃ
high cost oꢃ the catalysts and their low eꢂciency in separa-
tion and recovery ꢃrom reaction media. Thereꢃore, consider-
able eforts have been used to immobilize Pd compounds on
various separable supports such as activated carbon, silica
gel, polymers, metal oxides, porous aluminosilicates, clays,
and other organic, inorganic, or hybrid materials ꢃor decades
[19–21].
*
*
Majid Moghadam
moghadamm@sci.ui.ac.ir
Hossein Salavati
hosseinsalavati@yahoo.com
1
2
Department oꢃ Chemistry, Catalysis Division, University
oꢃ Isꢃahan, Isꢃahan 81746-73441, Iran
Department oꢃ Chemistry, Payame Noor University,
Tehran 19395-3697, Iran
Vol.:(0
1
123456789)
3

Journal of the Iranian Chemical Society
Graphene oxide, which is obtained by the oxidation oꢃ
graphite, has several oxygen-containing ꢃunctional groups
such as hydroxyl and epoxy groups on the basal planes, and
carbonyl and carboxyl groups at the edges that give rise to
its unique physical and chemical properties. Due to these
polar ꢃunctional groups in GO, the sorption and intercalation
oꢃ ions and molecules are possible [22–28]. During these
years, graphene (G) and graphene oxide (GO) have been
considered as a potential support ꢃor palladium-catalyzed
C–C coupling reactions [29–36].
ethanol (m.p. 223 °C). Elemental analysis calcd (%) ꢃor
C H I N O: C, 27.87; H, 3.40; N, 11.82. Found: C, 27.58;
1
1
16 2
4
H, 3.47; N, 11.51.
II
Then, the Pd (BIM) complex was obtained by adding
Pd(OAc) to a solution oꢃ compound 1 in DMSO. The
2
palladium(II) bis(imidazolium) complex as a yellow powder
was obtained ꢃrom recrystallization ꢃrom DMSO and ace-
tonitrile. Elemental analysis calcd (%) ꢃor C H I N OPd:
1
1
14 2
4
C, 23.78; H, 3.07; N, 8.53. Found: C, 23.52; H, 3.07; N,
8.53.
In continuation oꢃ our interest in the application oꢃ palla-
dium-based catalysts ꢃor organic transꢃormations [37–43],
here we report the preparation and characterization oꢃ a
palladium(II) complex oꢃ a ꢃunctionalized bis(imidazolium)
Preparation of graphene oxide‑supported
II
palladium(II) bis(imidazolium) complex, Pd (BIM)@
GO
II
ligand, Pd (BIM), immobilized on graphene oxide via non-
covalent method. The catalytic activity oꢃ the heterogeneous
The GO was prepared by the oxidation oꢃ graphite powder
with H SO and KMnO , according to the method described
II
and recyclable Pd (BIM)@GO catalyst was investigated in
2
4
4
Suzuki C–C coupling reactions.
by Hummers and Ofemann [45, 46]. The GO (200 mg) was
II
added to a solution oꢃ Pd (BIM) (10 mg) in H O/DMSO
2
(
100 ml, 100:1), and the brown suspension was sonicated ꢃor
Experimental
15 min. The mixture was vigorously stirred at room tempera-
ture ꢃor 24 h. At the end oꢃ the reaction, the resulting suspen-
sion was ꢁltered and thoroughly washed with water several
Materials and methods
II
times. Finally, the Pd (BIM)@GO catalyst was obtained
All the reagents were oꢃ analytical grade and used without
ꢃurther puriꢁcation. The chemicals used in this work were
purchased ꢃrom Fluka, Merck, and Sigma-Aldrich chemical
companies. The FT-IR and DR FT-IR spectra were recorded
with potassium bromide pellets on a JASCO 6300 spectro-
aꢃter a ꢃreeze-drying procedure (Yield: 89%).
General procedure for Suzuki–Miyaura
cross‑coupling reaction of aryl halides
II
with phenylboronic acid catalyzed by Pd (BIM)@GO
−1
photometer in the range 400–4000 cm . Difuse reꢀectance
UV–Vis spectra (DR UV–Vis) were recorded by a JASCO
V-670 UV–Vis spectrophotometer. The scanning electron
A mixture oꢃ aryl halide (1 mmol), phenylboronic acid
(1.3 mmol), K CO (2 mmol), and catalyst (0.35 mol% ꢃor
2
3
II
II
micrographs ꢃor morphological ꢃeatures oꢃ Pd (BIM)@GO
Pd (BIM)@GO) in DMF/H O (5 ml, 2:1) was stirred at
2
were taken on a Philips XL20 ꢁeld emission
‎
scanning elec-
60 °C under air atmosphere. The progress oꢃ the reaction
was monitored by GC. Aꢃter the completion oꢃ the reaction,
the catalyst was separated by centriꢃugation and the prod-
ucts were extracted with ethyl acetate. The organic phase
tron microscope (FE-SEM), equipped with an energy-dis-
persive X-ray analysis (EDAX) detector. Elemental analysis
was carried out on a LECO CHNS-932 analyzer. The ICP
ꢃor Pd content analyses oꢃ the catalyst was determined by a
PerkinElmer Optima 7300 DV spectrometer. The substances
were identiꢁed and quantiꢁed by gas chromatography (GC)
on an Agilent GC 6890 equipped with a 19096C006 80/100
WHP packed column and a ꢀame ionization detector (FID)
using n-decane as an internal standard.
was separated and dried over MgSO and evaporated under
4
reduced pressure.
Catalysts recovery
Due to the importance oꢃ recovery and reuse oꢃ heteroge-
neous catalysts ꢃrom green chemistry aspects, the reusabil-
II
Synthesis of palladium(II) bis(imidazolium) complex
ity oꢃ the Pd (BIM)@GO catalyst was investigated in the
Suzuki–Miyaura reaction oꢃ 4-iodoanisole with phenylbo-
ronic acid under the optimized reaction conditions. At the
end oꢃ each reaction, the reaction mixture was worked up as
described above and the ꢁltered catalyst was successively
reused in the same reaction and the ꢁltrate was used ꢃor the
determination oꢃ amount oꢃ Pd leached using ICP analysis.
The palladium(II) complex oꢃ a ꢃunctionalized
II
bis(imidazolium) ligand, Pd (BIM), was prepared accord-
ing to the literature method [44]. First, 1,3-bis(1-methylim-
idazolium-3-yl) propan2-one diiodide 1 as a bisimidazolium
ligand was prepared by the reaction oꢃ 1,3-dichloroacetone
with 1-methylimidazole and NaI in acetone. The resulting
brown precipitate was extracted with diethyl ether and
1
3

Journal of the Iranian Chemical Society
Results and discussion
Characterization of graphene oxide‑supported
II
palladium(II) bis(imidazolium) complex, Pd (BIM)@
GO
II
The preparation pathway ꢃor Pd (BIM)@GO catalyst is
shown in Scheme 1. As can be seen, the palladium(II) com-
plex oꢃ a ꢃunctionalized bis(imidazolium) ligand as a zwit-
terionic complex, with the negatively charged ligands at the
Pd(II) center balanced by the positive charges on the pen-
dant imidazolium groups [47], can be immobilized onto GO
II
nanosheets giving the Pd (BIM)@GO as heterogeneous cat-
alyst. The prepared catalyst was characterized by FT-IR and
DR UV–Vis, FE-SEM, EDX, ICP, and elemental analysis.
II
The FT-
‎
IR spectra oꢃ GO, Pd (BIM) complex, and
II
II
Pd (BIM)@GO catalyst are shown in Fig. 1. In the FT-
‎
IR
Fig. 1 FT-IR spectrum oꢃ a Pd (BIM) complex, b GO, and c
II
Pd (BIM)@GO catalyst
II
Scheme 1 Preparation route ꢃor the Pd (BIM)@GO catalysts
1
3

Journal of the Iranian Chemical Society
‎−‎1
spectrum oꢃ GO (Fig. 1a), the strong band at 1729 cm
(
C=O) represents carboxylic acid, and the bands at 1052,
‎−‎1
1
618, and 1226 cm are attributed to the C–O (epoxy),
C=C, and C–OH groups in graphene oxide, respectively.
‎−‎1
In addition, a broad band at 3428 cm is attributed to the
stretching mode oꢃ O–H bonds, due to the presence oꢃ many
hydroxyl groups.
The spectrum oꢃ catalyst (Fig. 1c) shows the parent char-
acteristic bands oꢃ GO and more new bands at 2927 and
−
1
1
384 cm related to the stretching vibration oꢃ CH (N) and
3
C=N in the imidazolium ring, respectively, that proved the
immobilization oꢃ palladium(II) bis(imidazolium) complex
on GO nanosheets. On the other hand, the presence oꢃ nitro-
gen in the elemental analysis oꢃ the catalyst related to imi-
II
dazolium groups conꢁrms the immobilization oꢃ Pd (BIM)
complex onto GO nanosheets.
II
The DR UV–Vis spectra oꢃ GO, Pd (BIM) complex, and
II
Pd (BIM)@GO catalyst are shown in Fig. 2. The UV
‎
–
‎
Vis
spectrum oꢃ GO shows a strong absorption peak at 214 nm
2
related to discrete units oꢃ sp -bonded carbons and a peak
around 300 nm, which is attributed to n − π* transition oꢃ
‎
C=O bonds (Fig. 2a). In the DR UV–Vis spectrum oꢃ the
II
Pd (BIM)@GO, the absorption peaks were appeared at 323,
2
14, 309, 341, and 389 nm (Fig. 2c) which showed the char-
acteristic peaks oꢃ the palladium(II) complex and also the
GO support.
The ꢁeld emission scanning electron microscopy (FE-
II
‎
SEM) micrograph oꢃ the Pd (BIM)@GO catalyst shows
the morphology oꢃ the surꢃace GO used in this study. As
can be seen, there are large ꢀakes oꢃ GO with macroscopic
wrinkled layered structure and smooth surꢃace. Also, the
spectrum oꢃ energy-dispersive X-ray (EDX) coupled to the
‎
SEM conꢁrmed the presence oꢃ Pd in the catalyst texture
and showed that the major elements are carbon and oxygen
(
Fig. 3).
The loading oꢃ the palladium(II) complex on GO, deter-
mined by measuring the pd content by ICP, was obtained
about 0.077 mol per gram oꢃ the catalyst.
II
Investigation of catalytic activity of Pd (BIM)@
GO catalyst in the Suzuki–Miyaura cross‑coupling
of aryl halides with phenylboronic acid reaction
II
The catalytic activity oꢃ Pd (BIM)@GO heterogeneous cata-
lyst was investigated in the Suzuki–Miyaura reaction oꢃ aryl
halides with phenylboronic acid. In this manner, as shown in
Table 1, the reaction parameters such as kind oꢃ solvent and
base, temperature, and catalyst amount were optimized in the
II
Fig. 2 The DR UV–Vis spectrum oꢃ a GO, b Pd (BIM) complex, and
II
c Pd (BIM)@GO catalyst
1
3

Journal of the Iranian Chemical Society
corresponding product was observed (entry 6). Then, the
model reaction was carried out in diferent organic/aqueous
media (Table 1, entries 11–13). Diferent aqueous solvents
such as DMF, EtOH, DMSO, and toluene were used as reac-
tion media, and higher yields were produced. When DMF/
H O (2:1) was used as solvent, higher yields oꢃ the desired
2
cross
‎
-coupling product were obtained, while in a nonpolar
solvent such as toluene the product yield was very low. This
can be attributed to the better solubility oꢃ reactants in this
solvent. Diferent organic and inorganic bases such as NEt ,
3
Na PO , and K CO were used in the model reaction (Table 1,
3
4
2
3
entries 8–10). Among them, K CO was ꢃound to be the most
2
3
eꢂcient base. Comparison oꢃ inorganic bases utilized showed
that carbonate base was more stable than the other one and an
organic base like NEt was not as eꢂcient as K CO . There-
3
2
3
ꢃore, it was concluded that 4-iodoanisole (1 mmol), phenylbo-
II
ronic acid (1.3 mmol), K CO (2 mmol), and Pd (BIM)@
2
3
GO (0.35 mol% Pd) in DMF/H O (5 ml, 2:1) at 60 °C were
2
selected as optimized conditions (Table 1, entries 3). Also,
as can be seen ꢃrom Table 1, longer time oꢃ reaction has no
efect on reaction yield in comparison with optimized condi-
tions (Table 1, entry 14).
A diversity oꢃ aryl halides was reacted with phenylbo-
ronic acid and 4-methoxyphenylboronic acid to produce
the substituted biphenyls under optimized conditions. As
can be seen ꢃrom Table 2, diferent aryl iodides, bromides,
and chlorides bearing electron-withdrawing and electron-
donating groups reacted eꢂciently with phenylboronic acid
and 4-methoxyphenylboronic acid to aꢃꢃord the desired
cross-coupling products in high yields. As expected, aryl
iodides were ꢃound to be more reactive than aryl bromides
and chlorides.
The complex is a Pd(II) complex, and many Pd(II) com-
plexes have been reported to catalyze this reaction [37–42].
In the mechanism oꢃ Suzuki–Miyaura reaction catalyzed by
II
II
Fig. 3 The FE-SEM images and EDX spectrum oꢃ Pd (BIM)@GO
Pd (BIM)@GO, the Pd(II) is responsible ꢃor Pd(0) species.
catalyst
II
Table 3 compares the activity oꢃ the Pd (BIM)@GO cata-
lyst (yield, time, reaction conditions) with various heteroge-
neous GO-based palladium catalysts in Suzuki reaction oꢃ
aryl iodide and phenylboronic acid. It is clear ꢃrom Table 3
that our catalyst is more eꢂcient and less time-consuming
ꢃor the Suzuki reaction.
coupling oꢃ 4-iodoanisole (1 mmol) with phenylboronic acid
II
(
1.3 mmol) in the presence oꢃ Pd (BIM)@GO monitored by
GC. In the optimization oꢃ the amount oꢃ catalysts, difer-
ent amounts oꢃ catalyst were used and the best results were
II
obtained using 0.0035 mol oꢃ Pd (BIM)@GO (Table 1, entries
1
–4). No product was detected, in the absence oꢃ catalyst.
Catalyst recovery and reuse
This coupling reaction was ꢃound to be highly sensitive to the
reaction temperature (Table 1, entries 5–7). A reaction tem-
perature oꢃ 60 °C was ꢃound to be optimal. When the model
reaction was carried out at room temperature, only 52% oꢃ
The recovery and reuse oꢃ a heterogeneous catalyst are oꢃ
great importance ꢃrom economical, industrial, and green
II
chemistry points oꢃ view. The reusability oꢃ the Pd (BIM)@
1
3

Journal of the Iranian Chemical Society
Table 1 Optimization oꢃ
conditions in the Suzuki
reaction oꢃ 4-iodoanisole and
phenylboronic acid catalyzed by
II
Pd (BIM)@GO
Entry
Solvent
Pd (mol%)
Base
T (°C)
Time (min)
Yield (%)a
1
2
3
4
5
6
7
8
9
1
1
1
1
1
DMF/H O (2:1)
0
0.1
0.35
1
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
K CO
60
60
60
60
80
r.t.
40
60
60
60
60
60
60
60
–
0
64
100
99
98
52
32
7
74
56
91
76
34
100
2
2
3
3
3
3
3
3
3
DMF/H O (2:1)
K CO
35
10
4
2
2
DMF/H O (2:1)
K CO
2
2
DMF/H O (2:1)
K CO
2
2
DMF/H O (2:1)
K CO
6
2
2
DMF/H O (2:1)
K CO
40
25
55
15
20
10
10
10
25
2
2
DMF/H O (2:1)
K CO
2
2
DMF/H O (2:1)
No Base
Na PO
2
DMF/H O (2:1)
2
3
4
0
1
2
3
4
DMF/H O (2:1)
NEt3
2
DMSO/H O (2:1)
K CO
2
2
3
EtOH/H O (2:1)
K CO
2
2
3
3
3
Toluene/H O (2:1)
K CO
2
2
DMF/H O (2:1)
K CO
2
2
Reaction conditions: 4-iodoanisole (1 mmol), phenylboronic acid (1.3 mmol), base (2 mmol), solvent
(
5 ml) under air atmosphere
Yields were determined by GC
a
Table 2 Suzuki cross-
‎
coupling reaction catalyzed by
II
Pd (BIM)@GO
Pd (BIM)@GOa
II
Entry
R1
R2
H
X
Time (min)
Yield (%)b
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
H
H
I
I
I
I
I
I
I
Br
Br
Br
Br
Br
Cl
Cl
Cl
Cl
Cl
12
15
8
99
93
97
94
100
87
83
93
89
93
91
95
67
66
98
34
92
4
‎
4
4
‎
H
‎
‎
4
‎
‎
8
4
4
‎
‎
H
H
10
15
17
35
30
26
29
32
75
80
45
75
70
‎
‎
2
4
‎
‎
4
‎
‎
2
H
4‎-MeO
H
H
H
‎
1
1
1
1
1
1
1
1
4-NO
‎
‎
2
4
4
‎
‎
4‎-MeO
‎
2
‎
‎
H
H
4‎-MeO
H
H
4-
‎
‎
H
H
H
4-
4-
‎
‎
2
Reaction conditions: aryl halide (1 mmol), phenylboronic acid (1.3 mmol), K CO (2 mmol), DMF/H O
2
3
2
(
2:1, 5 ml) under air
a
6
0 °C, catalyst (0.35 mol% Pd)
b
Yields determined by GC
1
3

Journal of the Iranian Chemical Society
Table 3 Comparison
Catalyst
Conditions
Yield (%)
Time
Reꢃerences
oꢃ eꢂciency oꢃ various
heterogeneous GO-based
palladium catalysts in Suzuki
reaction oꢃ aryl iodide and
phenylboronic acid
PdII(BIM)@GO (0.35 mol%)
GO–NHC–Pd (0.25 mol%)
NHC–Pd/GO–IL (0.1 mol%)
GO–Pd (0.5 mol%)
K CO , DMF/H O (2:1), 60 °C
100
96
98
93
93
10 min
1 h
2.5 h
30 min
5 min
This work
[48]
[49]
[50]
[33]
2
3
2
K CO , EtOH/H O (1:1), 80 °C
2
3
2
K CO , EtOH/H O (1:1), 60 °C
2
3
2
K CO , EtOH, 60 °C
2
3
GO–Pd (1.1 mol%)
K PO , H O, 100 °C
3
4
2
II
high catalytic activity, and good reusability with low leach-
ing oꢃ Pd aꢃter the completion oꢃ the reaction, are noteworthy
advantages oꢃ this catalytic system in the Suzuki–Miyaura
coupling reaction. Further applications oꢃ this new catalytic
system in other palladium-catalyzed reactions are under
investigation in our laboratory.
Table 4 Recycling and reuse oꢃ Pd (BIM)@GO in the Suzuki–
Miyaura reaction
Acknowledgements The authors are grateꢃul to acknowledge the sup-
port oꢃ this work by the Research Council oꢃ the University oꢃ Isꢃahan
and Payame Noor University oꢃ Tehran.
II
Entry
Pd (BIM)@GO
Yield (%)a
Pd leached (%)b
1
2
3
4
5
100
99
99
97
95
1
0.5
–
–
–
References
1
.
K.S. Novoselov, A.K. Geim, S. Morozov, D. Jiang, Y. Zhang, S.
Dubonos, I. Grigorieva, A. Firsov, Science 306, 666 (2004)
2. A.K. Geim, Science 324, 1530 (2009)
3
.
C.N.R. Rao, A.K. Sood, K.S. Subrahmanyam, A. Govindaraj,
Reaction conditions: 4-iodoanisole (1 mmol), phenylboronic acid
Angew. Chem. Int. Ed. 48, 7752 (2009)
(
(
a
1.3 mmol), K CO (2 mmol), catalyst (0.35 mol% Pd), DMF/H O
2
3
2
4. J. Wu, W. Pisula, K. Mullen, Chem. Rev. 107, 718 (2007)
2:1, 5 ml) under air at 60 °C aꢃter 10 min
Yields determined by GC
5
.
S. Stankovich, D.A. Dikin, G.H.B. Dommett, K.M. Kohlhaas, E.J.
Zimney, E.A. Stach, R.D. Piner, S.T. Nguyen, R.S. Ruof, Nature
442, 282 (2006)
b
Determined by ICP analysis
6
.
G. Eda, G. Fanchini, M. Chhowalla, Nat. Nanotechnol. 3, 270
(
2008)
7
8
.
.
P.V.J. Kamat, Phys. Chem. Lett. 1, 520 (2010)
GO catalyst was investigated in the reaction oꢃ 4-iodoani-
sole (1.0 mmol), phenylboronic acid (1.3 mmol), K CO
G. Williams, B. Seger, P.V. Kamat, ACS Nano 2, 1487 (2008)
9. Z. Luo, L.A. Somers, Y. Dan, T. Ly, N.J. Kybert, E.J. Mele, A.T.
2
3
Charlie Johnson, Nano Lett. 10, 777 (2010)
(
2 mmol), and catalyst (0.35 mol%) at 60 °C. At the end
1
0. N.M. Julkapli, S. Bagheri, Int. J. Hydrog. Energy 40, 948 (2015)
oꢃ each reaction, the catalyst was ꢁltered and washed thor-
oughly with diethyl ether, acetone, and water and reused
with ꢃresh 4-iodoanisole and phenylboronic acid. The results
are summarized in Table 4. As can be seen, the catalyst
was recovered and recycled ꢁve consecutive times without
remarkable loss oꢃ its catalytic activity (95%). The amount
oꢃ Pd leached was determined by ICP analysis. As can be
seen, aꢃter second run, no catalyst was leached ꢃrom catalyst.
1
1. Y. Li, X. Fan, J. Qi, J. Ji, S. Wang, G. Zhang, F. Zhang, Nano Res.
3
, 429 (2010)
12. Q. Chen, Z. Ye, Y. Duan, Y. Zhou, Chem. Soc. Rev. 42, 497
(
2013)
1
1
3. R.B. Bedꢃord, C.S.J. Cazin, D. Holder, Coord. Chem. Rev. 248,
2
283 (2004)
4. M. Larhed, A. Hallberg, in Handbook of organopalladium chem-
istry for organic synthesis, ed. by E. Negishi (Wiley, New York,
2
002), p. 1133
1
5. L. Liu, J.E. Stelmach, S.R. Natarajan, M.H. Chen, S.B. Singh,
C.D. Schwartz, C.E. Fitzgerald, S.J. O’Keeꢃe, D.M. Zaller, D.M.
Schmatz, J.B. Doherty, Bioorg. Med. Chem. Lett. 13, 3979
(2003)
Conclusion
1
1
6. W.J. Sommer, M. Weck, Coord. Chem. Rev. 251, 860 (2007)
7. N. Debono, A. Labande, E. Manoury, J.C. Daran, R. Poli, Orga-
nometallics 29, 1879 (2010)
In summary, we developed a new type oꢃ heterogeneous
catalyst by the immobilization oꢃ palladium(II) complex oꢃ
ꢃunctionalized bis(imidazolium) ligand on graphene oxide
1
1
8. L.R. Titcomb, S. Caddick, F.G.N. Cloke, D.J. Wilson, D. McKer-
recher, Chem. Commun. 1388 (2001)
9. K. Shimizu, R. Maruyama, S. Komai, T. Kodama, Y. Kitayama,
J. Catal. 228, 141 (2004)
(
GO) as a stable support ꢃor the immobilization and stabili-
zation oꢃ Pd nanoparticles. Simple preparation oꢃ catalyst,
1
3

Journal of the Iranian Chemical Society
2
0. S. Fujii, S. Matsuzawa, Y. Nakamura, A. Ohtaka, T. Teratani,
Langmuir 26, 6230 (2010)
37. F. Sadegh, O. Bagheri, M. Moghadam, V. Mirkhani, S. Tangesta-
ninejad, I. Mohammadpoor-Baltork, J. Organomet. Chem. 759,
46 (2014)
2
2
1. A. Corma, H. Garcia, Adv. Synth. Catal. 348, 1391 (2006)
2. H. He, J. Klinowski, M. Forster, A. Lerꢃ, Chem. Phys. Lett. 287,
38. M. Ghotbinejad, A.R. Khosropour, I. Mohammadpoor-Baltork,
M. Moghadam, S. Tangestaninejad, V. Mirkhani, J. Mol. Catal.
A Chem. 385, 78 (2014)
5
3 (1998)
2
2
3. D.W. Boukhvalov, M.I. Katsnelson, J. Am. Chem. Soc. 130, 10697
(
2008)
39. Z. Pahlevanneshan, M. Moghadam, V. Mirkhani, S. Tangestan-
inejad, I. Mohammadpoor-Baltork, A.R. Khosropour, Appl. Orga-
nomet. Chem. 29, 346 (2015)
4. M.J. McAllister, J.L. Li, D.H. Adamson, H.C. Schniepp, A.A.
Abdala, J. Liu, M. Herrera-Alonso, D.L. Milius, R. Car, Chem.
Mater. 19, 4396 (2007)
40. Z. Pahlevanneshan, M. Moghadam, V. Mirkhani, S. Tangestan-
inejad, I. Mohammadpoor-Baltork, S. Rezaei, Appl. Organometal.
Chem. 29, 678 (2015)
2
2
2
2
2
3
3
3
3
3
5. S. Stankovich, R.D. Piner, S.T. Nguyen, R.S. Ruof, Carbon 44,
3
342 (2006)
6. D.R. Dreyer, S. Park, C.W. Bielawski, R.S. Ruof, Chem. Soc.
Rev. 39, 228 (2010)
41. Z. Pahlevanneshan, M. Moghadam, V. Mirkhani, S. Tangestan-
inejad, I. Mohammadpoor-Baltork, H. Loghmani-Khouzani, J.
Organomet. Chem. 809, 31 (2016)
7. Y.W. Zhu, S. Murali, W.W. Cai, X.S. Li, J.W. Suk, J.R. Potts, R.S.
Ruof, Adv. Mater. 22, 3906 (2010)
42. Z. Pahlevanneshan, M. Moghadam, V. Mirkhani, S. Tangestan-
inejad, I. Mohammadpoor-Baltork, S. Rezaei, New J. Chem. 39,
9729 (2015)
8. A.B. Bourlinos, D. Gournis, D. Petridis, T. Szabo, A. Szeri, I.
Dekany, Langmuir 19, 6050 (2003)
9. G.M. Scheuermann, L. Rumi, P. Steurer, W. Bannwarth, R. Mul-
haupt, J. Am. Chem. Soc. 131, 8262 (2009)
43. M. Zakeri, M. Moghadam, V. Mirkhani, S. Tangestaninejad,
I. Mohammadpoor-Baltork, Z. Pahlevanneshan, RSC Adv. 6,
104608 (2016)
0. A.R. Siamaki, A. Rahman, S. Khder, V. Abdelsayed, M.S. El-
Shall, B.F. Gupton, J. Catal. 279, 1 (2011)
44. J. Nielsen, J. Cavell, W. Skelton, H. White, Organometallics 20,
995 (2001)
1. L. Rumi, G.M. Scheuermann, R. Mulhaupt, W. Bannwarth, Helv.
Chim. Acta 94, 966 (2011)
45. W.S. Hummers, R.E. Ofeman, J. Am. Chem. Soc. 80, 1339 (1957)
46. S. Stankovich, A.D. Dmitriy, O.C. Compton, G.H.B. Dommett,
R.S. Ruof, S.T. Nguyen, Chem. Mater. 22, 4153 (2010)
47. K. Kohler, R.G. Heidenreich, J.G.E. Krauter, J. Pietsch, Chem.
Eur. J. 8, 622 (2002)
2. X.K. Kong, Q.W. Chen, Z.Y. Lun, Chem. Phys. Chem. 15, 344
(
2014)
3. L. Yang, F. Xiaobin, Q. Junjie, J. Junyi, W. Shulan, Z. Guoliang,
Nano Res. 3, 429 (2010)
4. M. Sheriꢃ, A.R. Siamak, G.B. Frank, E.S.M. Samy, ACS Catal. 2,
48. N. Shang, S. Gao, C. Feng, H. Zhang, C. Wang, Z. Wang, RSC
Adv. 3, 21863 (2013)
1
45 (2012)
3
3
5. M. Sarvestani, R. Azadi, Appl. Organomet. Chem. 367, 1 (2016)
6. S.J. Hoseini, B. Habib Agahi, Z. Samadi Fard, R. Hashemi Fath,
M. Bahrami, Appl. Organomet. Chem. 31, e367 (2017). https://
doi.org/10.1002/aoc.3607
49. S. Kazemi Movahed, R. Esmatpoursalmani, A. Bazgir, RSC Adv.
4, 14586 (2014)
50. C. Bai, Q. Zhao, G. Zhang, Y. Li, F. Zhang, X. Fan, Catal. Lett.
144, 1617 (2014)
1
3