Organometallic polymer-functionalized Fe3O4 nanoparticles as a highly efficient and eco-friendly nanocatalyst for C–C bond formation

Article abstract of DOI:10.1007/s11243-018-0233-5

A magnetically recoverable biopolymer-based nanocatalyst was prepared through the covalent immobilization of a chitosan-bound 2-hydroxynaphthaldehyde Pd complex on the surface of superparamagnetic nanoparticles. The nanocatalyst was characterized by FTIR, X-ray powder diffraction and scanning electron microscopy, revealing an average particle size of 70?nm. The catalyst shows high thermostability by thermogravimetric analysis. Estimated Pd loading by inductively coupled plasma atomic emission analysis was found to be 0.348?mmol?g^?1. The nanocatalyst exhibits excellent catalytic performance in Suzuki couplings of various aryl halides with phenylboronic acid, and Heck reactions of iodo- and bromoarenes with butylacrylate. The catalyst can be easily separated from the reaction mixture with an external magnet and reused consecutively four times without significant loss in activity.

Full text of DOI:10.1007/s11243-018-0233-5

Transition Metal Chemistry
https://doi.org/10.1007/s11243-018-0233-5
Organometallic polymer‑functionalized Fe O nanoparticles
3
4
as a highly eꢀcient and eco‑friendly nanocatalyst for C–C bond
formation
Akram Fakhri · Ali Naghipour1
1
Received: 4 February 2018 / Accepted: 3 April 2018
©
Springer International Publishing AG, part of Springer Nature 2018
Abstract
A magnetically recoverable biopolymer-based nanocatalyst was prepared through the covalent immobilization of a chitosan-
bound 2-hydroxynaphthaldehyde Pd complex on the surface of superparamagnetic nanoparticles. The nanocatalyst was
characterized by FTIR, X-ray powder diꢀraction and scanning electron microscopy, revealing an average particle size of
7
0 nm. The catalyst shows high thermostability by thermogravimetric analysis. Estimated Pd loading by inductively coupled
−
1
plasma atomic emission analysis was found to be 0.348 mmol g . The nanocatalyst exhibits excellent catalytic performance
in Suzuki couplings of various aryl halides with phenylboronic acid, and Heck reactions of iodo- and bromoarenes with buty-
lacrylate. The catalyst can be easily separated from the reaction mixture with an external magnet and reused consecutively
four times without signiꢁcant loss in activity.
Introduction
handle than their homogeneous counterparts, are often less
eꢀective and can also be diꢂcult to separate from the reac-
tion mixture.
Palladium-catalyzed carbon–carbon cross-coupling reac-
tions, especially Suzuki–Miyaura [1–4] and Heck–Mizoroki
In the last decades, the challenge of designing new cata-
lysts that simultaneously provide the advantages of both
homogeneous and heterogeneous catalysts has provided an
important goal for the chemical community. With the sig-
niꢁcant advances in nanoscience, further attempts have been
made to develop quasi-homogeneous and nanostructured
catalysts which can act as a bridge between homogeneous
and heterogeneous catalysts.
[
5–8] coupling reactions, play a role key in the synthesis of
pharmaceutical intermediates and agrochemicals, as well
as in starting materials for conducting polymers and liquid
crystalline materials. A variety of homogeneous and hetero-
geneous palladium catalytic systems have been developed
to carry out these transformations under various reaction
conditions. However, the homogenous Pd catalysts gener-
ally used in these reactions suꢀer a number of drawbacks
such as tedious and time-consuming workup, diꢂculty in
puriꢁcation of the ꢁnal products, problems in recycling of
the catalysts, and contamination of the coupling products
with palladium species, especially when they are used for
the production of pharmaceutical products. In addition, most
homogeneous palladium complexes are generally based on
phosphine ligands [9, 10], which have associated problems
like toxicity, air and moisture sensitivity, and high cost. Fur-
thermore, heterogeneous catalysts, despite being easier to
Magnetically recyclable nanocatalysts based on magnetite
(Fe O ) as a support have emerged as a promising area of
3
4
study, as they not only present excellent catalytic activities
and good chemical stability but also the magnetic nature of
these catalysts facilitates their separation from the reaction
media. Hence, in the present study, we have designed and
prepared a novel heterogeneous palladium catalyst via func-
tionalization of Fe O nanoparticles with chitosan. Chitosan
3
4
is a natural, biocompatible and biodegradable amino-poly-
saccharide, which, because of special properties including
non-toxicity, biocompatibility, biodegradability, low immu-
nogenicity and antibacterial properties, has shown applica-
tions in several ꢁelds. Functionalization of the free amine
groups in chitosan with 2-hydroxynaphthaldehyde provides
new active sites for grafting of Pd ions. The catalytic activity
*
Ali Naghipour
naghipour2002@yahoo.com
1
Department of Chemistry, Faculty of Science, Ilam
University, Ilam, Iran
Vol.:(0
1
123456789)
3

Transition Metal Chemistry
of this magnetically recyclable palladium catalyst was evalu-
ated in Suzuki and Heck C–C cross-coupling reactions.
2-hydroxynaphthaldehyde (1.0 g) in ethanol (60 mL). The
resulting mixture was reꢃuxed for 24 h under nitrogen. The
magnetic nanocatalyst was collected by means of an external
magnet, washed with ethanol and dried under vacuum.
Experimental
General procedure for the Suzuki reaction
All starting materials were of high purity as purchased
from Merck and Aldrich. FTIR spectra were recorded on
a VRTEX 70 model Bruker FTIR spectrophotometer in
A mixture of aryl halide (1 mmol), phenylboronic acid
(1.2 mmol), K CO (1.5 mmol), nanocatalyst (25 mg) and
2
3
−
1
the range of 400–4000 cm using KBr pellets. Thermo-
gravimetric analysis (TGA) was carried out under air on
a Shimadzu DTG-60 instrument. X-ray diꢀraction (XRD)
data were collected on a Rigaku Dmax 2500 diꢀractom-
eter with CuKα radiation (λ=1.54406 Å). The morphology
of the catalyst was observed with a Philips XL30 scanning
electron microscope (SEM). Palladium content of the cata-
lyst was measured by inductively coupled plasma atomic
emission analysis (ICP-AES) VISTA-PRO. Known products
PEG (4 mL) was placed in an overpressure screw-capped
vial and stirred at 100 °C for the required reaction time.
After completion of the reaction, as judged by TLC, the
reaction mixture was cooled to room temperature. The cata-
lyst was separated by magnetic decantation, washed with
water and EtOH and dried for the next run. The decantate
was diluted with H O (10 mL), and the organic phase was
2
extracted with diethyl ether (3×20 mL). The organic extract
was dried over Na SO , ꢁltered and concentrated under
2
4
1
were characterized by comparison of their spectral ( HNMR,
reduced pressure to get the desired product. These crude
Bruker NMR Spectrometer FX 400Q) and physical data with
those of authentic samples.
products were puriꢁed by recrystallization.
1
4-Nitro-1,1′-biphenyl: H NMR (400 MHz, CDCl ) δ
3
(
ppm): 8.35–8.32 (m, 2H), 7.79–7.76 (m, 2H), 7.67–7.64
Preparation of the nanocatalyst
(m, 2H), 7.56–7.46 (m, 3H).
1
4
-Methoxy-1,1′-biphenyl: H NMR (400 MHz, CDCl ) δ
3
First, magnetic Fe O nanoparticles were synthesized
(ppm): 7.60–7.55 (m, 4H), 7.47–7.43 (m, 2H), 7.36–7.29 (m,
3
4
according to the chemical coprecipitation method [11].
1H), 7.03–7.00 (d, J=8.8 Hz, 2H), 3.89 (s, 3H).
1
FeCl 6H O (2 mmol) and FeCl ·4H O (1 mmol) were dis-
[1,1′-Biphenyl]-4-carbonitrile: H NMR (400 MHz,
3
2
2
2
solved in deionized water (100 mL) at 70 °C, and the solu-
CDCl ) δ (ppm): 7.77–7.70 (m, 4H), 7.64–7.61 (m, 2H),
3
tion was stirred vigorously under a nitrogen atmosphere for
7.54–7.44 (m, 2H).
3
0 min. Concentrated ammonia solution (10 mL) was then
added quickly to the mixture in one portion, and stirring
was continued for another 30 min. The reaction mixture was
then cooled; the magnetite precipitates were magnetically
collected, washed several times with deionized water and
dried overnight.
General procedure for the Heck reaction
In a typical reaction, an overpressure screw-capped vial
was charged with aryl halide (1 mmol), n-butyl acrylate
(1.5 mmol), Et N (1.5 mmol), the catalyst (25 mg) and
3
Chitosan-functionalized Fe O nanoparticles were pre-
N,N-dimethylformamide (4 mL). The reaction mixture was
stirred at 130 °C for the required time. After completion of
the reaction as monitored by TLC, the mixture was cooled
to room temperature; the catalyst was separated with a per-
manent magnet, washed with water and EtOH and dried for
3
4
pared according to the reported procedure [12]. Freshly
precipitated magnetite (1 g) was dispersed in a solution of
chitosan (3 g) in 2% (v/v) acetic acid solution (300 mL). The
resulting mixture was stirred at room temperature for 1 h
and then neutralized with 10% (w/v) NaHCO solution. The
the next run. The decantate was diluted with H O (10 mL),
3
2
precipitate was magnetically separated, washed twice with
followed by extraction with ethyl acetate (3×20 mL). The
deionized water and dried at 60 °C.
combined organic layers were dried over anhydrous Na SO ,
2
4
A portion of the freshly prepared chitosan-functionalized
Fe O nanoparticles (1 g) was dispersed in ethanol (40 mL)
ꢁltered, and concentrated to get the desired product. The
crude products were puriꢁed by recrystallization.
3
4
1
by sonication for 30 min. The resultant mixture was charged
with a solution of 2-hydroxynaphthaldehyde (5 mmol) in
ethanol (10), and the mixture was reꢃuxed under nitrogen
for 24 h and then cooled. The resulting nanoparticles were
magnetically separated, washed several times with ethanol
and then dried under vacuum.
(E)-n-Butyl cinnamate: H NMR (400 MHz, CDCl ) δ
3
(ppm): 7.72 (d, 1H), 7.57–7.54 (m, 2H), 7.42–7.39 (m, 3H),
6.48 (d, 1H), 4.25 (t, 2H), 1.76–1.69 (m, 2H), 1.50–1.46 (m,
2H), 1.00 (t, 3H).
1
(E)-n-Butyl 3-(4-methylphenyl)acrylate: H NMR
(400 MHz, CDCl ) δ (ppm): 7.69 (d, 1H), 7.45 (d, 2H), 7.22
3
Finally, palladium chloride (5 mmol) was added
to a suspension of dispersed Fe O @chitosan-bound
(d, 2H), 6.43 (d, 1H), 4.23 (t, 2H), 2.40 (s, 3H), 1.75–1.68
(m, 2H), 1.50–1.44 (m, 2H), 1.00 (t, 3H).
3
4
1
3

Transition Metal Chemistry
1
−1
(
E)-n-Butyl 3-(4-nitrophenyl)acrylate: HNMR
characteristic sharp band at 1623 cm in Fig. 1c, assigned
(
400 MHz, CDCl , δ): 7.65 (d, 1H), 7.49–7.46 (m, 2H),
to the imine group (C=N). On the complexation with pal-
ladium chloride, the C=N peak is shifted to lower wave
3
7
.40–7.37 (m, 2H), 6.43 (d, 1H), 4.25–4.22 (m, 2H), 2.35
−
1
(
(
s, 3H), 1.62–1.70 (m, 2H), 1.75–1.68 (m, 2H), 1.49–1.43
m, 2H), 0.99 (t, 3H).
number at 1612 cm (Fig. 1d), indicative of a metal–ligand
interaction.
The size and morphology of the Fe O @chitosan-bound
3
4
2
-hydroxynaphthaldehyde Pd complex were investigated
Results and discussion
by SEM. As shown in Fig. 2, the average diameter of the
nanoparticles is estimated to be less than 70 nm, with nearly
spherical shape.
The synthesis of the Pd complex of functionalized chitosan
supported on Fe O nanoparticles is illustrated in Scheme 1.
The crystalline structures of the Fe O nanoparticles and
3
4
3
4
First, the magnetite Fe O nanoparticles were prepared by
Fe O @chitosan-bound 2-hydroxynaphthaldehyde Pd cata-
3
4
3 4
the conventional coprecipitation of Fe(III) and Fe(II) in
lyst were investigated by XRD (Fig. 3). The XRD patterns of
basic solution. The Fe O nanoparticles were then function-
the Fe O nanoparticles include peaks at 2θ=30.14°, 35.72°,
3
4
3
4
alized with chitosan, followed by treatment of the chitosan
amino groups with 2-hydroxynaphthaldehyde in ethanol
under reꢃux for 24 h. Finally, reaction of the as-synthesized
43.42°, 54.12°, 57.97° and 63.96°, which are, respectively,
attributed to the (2 2 0), (3 1 1), (4 0 0), (4 2 2), (5 1 1), and
(4 4 0) phases of Fe O , indexed to the crystalline cubic spi-
3
4
nanoparticles with PdCl led to the corresponding Pd com-
nel structure of standard Fe O nanoparticles. The observed
2
3 4
plex of chitosan supported on the nanoparticles.
diꢀraction peaks appearing in the XRD of the synthesized
nanocatalyst, which are also comparable with standard mag-
netite XRD patterns, indicate retention of crystallinity dur-
ing the immobilization process. New peaks at 2θ=40.18°,
44.28° and 67.16° are attributed to the Pd species.
Catalyst characterization
The nanocatalyst was characterized using a variety of dif-
ferent techniques. The FTIR spectrum of the nanocatalyst is
The thermal stability and organic content of the Fe O @
3
4
−
1
shown in Fig. 1. The characteristic peak around 580 cm is
due to the vibrations of the Fe–O bonds (Fig. 1a). A broad-
chitosan-bound 2-hydroxynaphthaldehyde Pd complex were
measured by TGA (Fig. 4). The observed weight loss for the
nanocatalyst below 150 °C is ascribed to the loss of adsorbed
water or solvent. Around 150–770 °C, a large weight reduc-
tion occurred, which can be attributed to decomposition of
the chitosan-bound 2-hydroxynaphthaldehyde Pd complex.
From the observed weight loss, it was estimated that the
organic content in the catalyst is about 40 wt%. The pal-
ladium content was found to be 0.348 mmol per gram of the
catalyst, based on the ICP-AES chemical analysis.
−
1
−1
band at 3399 cm and a band at 1625 cm are assigned
to the stretching and bending vibrations of the surface OH
groups. In the spectrum of the chitosan-functionalized
Fe O nanoparticles (Fig. 1b), additional peaks at 2924 and
3
4
−
1
−1
2
854 cm and a band at 1624 cm are attributed to the
aliphatic C–H and N–H stretching vibrations, respectively.
Successful reaction of Fe O @chitosan with 2-hydrox-
3
4
ynaphthaldehyde can be inferred from the appearance of a
Scheme 1 Schematic illustration for the synthesis of Fe O @chitosan-bound 2-hydroxynaphthaldehyde Pd complex
3
4
1
3

Transition Metal Chemistry
Fig. 1 FTIR spectra of a Fe O
3
4
nanoparticles, b Fe O @chi-
3
4
tosan, c Fe O @chitosan-bound
3
4
2
-hydroxynaphthaldehyde
and d Fe O @chitosan-bound
3
4
2
-hydroxynaphthaldehyde Pd
complex
Fig. 2 SEM images of Fe O @chitosan-bound 2-hydroxynaphthaldehyde Pd complex
3
4
1
3

Transition Metal Chemistry
Fig. 4 TGA curves for Fe O nanoparticles and Fe O @chitosan-
3
4
3
4
bound 2-hydroxynaphthaldehyde Pd complex
Fig. 3 XRD patterns of Fe O @chitosan-bound 2-hydroxynaphthal-
4-nitrobromobenzene with phenylboronic acid was chosen as
a model reaction (Scheme 2) in order to study the inꢃuence
of catalyst loading, base, solvent and temperature (Table 1).
As listed in Table 1, the nanocatalyst played a signiꢁcant
role in the C–C coupling reaction. When the model reaction
was carried out in the absence of the catalyst, no product was
obtained. On testing diꢀerent amounts of the catalyst, 25 mg
was found to be optimal; higher amount of catalyst did not
have any signiꢁcant impact on the progress of the reaction.
3
4
dehyde Pd complex
Catalytic activity in Suzuki and Heck reactions
The catalytic efficacy of the nanocatalyst was initially
explored in Suzuki–Miyaura coupling reactions. In order
to optimize the reaction parameters, the reaction of
Scheme 2 Suzuki coupling of 4-nitrobromobenzene with phenyl boronic acid catalayzed by Fe O @chitosan-bound 2-hydroxynaphthaldehyde
3
4
Pd complex
Table 1 Optimization
of parameters for the
Suzuki reaction of
a
Entry
Base
–
Solvent
T (°C)
Catalyst (mg)
Time (min)
Yield (%)
1
2
3
4
5
6
7
8
9
0
1
2
3
PEG
PEG
PEG
PEG
PEG
PEG
80
80
80
80
80
80
80
80
60
100
110
100
100
20
–
10 h
24 h
65
60
70
100
100
70
70
50
–
–
4
-nitrobromobenzene with
K CO
2
3
phenyl boronic acid
K CO
20
20
20
20
20
20
20
20
20
25
30
65
45
30
5
35
45
50
80
82
93
94
2
3
NaHCO3
NaOAc
Et N
3
K CO
H O
2
3
3
3
3
3
3
3
2
K CO
DMF
DMSO
PEG
PEG
PEG
2
K CO
2
1
1
1
1
K CO
2
K CO
50
50
45
2
K CO
2
K CO
PEG
2
Reaction conditions: nitrobromobenzene (1 mmol), phenyl boronic acid (1.2 mmol), base (1.5 mmol) and
solvent (2 mL)
a
Yields refer to those of pure isolated products
1
3

Transition Metal Chemistry
Scheme 3 Suzuki coupling of
aryl halides, 2-iodothiophene
and 2-bromonaphthalene with
phenyl boronic acid catalyzed
by Fe O @chitosan-bound
3
4
2
-hydroxynaphthaldehyde Pd
complex
Next, the model reaction was carried out in the presence
and electron-withdrawing substituents) were subjected to the
Suzuki reaction under the optimal conditions (Scheme 3). As
listed in Table 2, the couplings between aryl iodides and bro-
mides with various electron-donating and electron-withdraw-
ing substituents and phenyl boronic acid proceeded eꢀectively
to aꢀord the corresponding products in good-to-excellent
conversions. Ortho-substituted aryl iodides and bromides
required longer reaction times than para-substituted, because
of steric eꢀects. Encouragingly, the nanocatalyst exhibited
good activity toward chlorobenzene.
of various organic and inorganic bases. Comparison of the
results shows that the reaction in the presence of K CO
2
3
aꢀorded the product in the highest yield.
Next, the solvent screening demonstrated that polyethyl-
ene glycol (PEG) was the most appropriate choice. Further
experiments carried out at diꢀerent temperatures showed
that model reaction gave best results at 100 °C.
Next, in order to demonstrate the versatility of the nanocat-
alyst, a series of aryl halides (including both electron-donating
The catalytic performance of the nanocatalyst was further
investigated in Heck reactions of iodo- and bromobenzene
with n-butyl acrylate. In order to determine the optimum
reaction conditions, the reaction of iodobenzene with n-butyl
acrylate was taken as a model (Scheme 4). Table 3 presents
optimization data for the catalyst loading, base, solvent and
temperature. Based on these results, it was found that 25 mg
of the catalyst can eꢀectively catalyze the model reaction
using K CO as base in DMF at 130 °C.
Table 2 Suzuki coupling of aryl halides with phenyl boronic acid cata-
lyzed by Fe O @chitosan-bound 2-hydroxynaphthaldehyde Pd complex
3
4
Entry R
X
Time (min) Yield (%)a Mp (°C) [References]
1
2
3
4
H
I
I
I
I
15
55
35
74
94
92
96
90
68–70 [13]
49–51 [14]
46–48 [15]
p-NH2
p-Me
o-Me
2
3
Light yellow liquid
In order to explore the general applicability of the cata-
lyst, coupling reactions of diꢀerent aryl iodides and bro-
mides containing electron-withdrawing or electron-donating
substituents were evaluated (Scheme 5). The results are
listed in Table 4. As expected, for aryl iodides and electron-
poor aryl bromides, the yields were generally good. For
electron-rich bromobenzenes, and the yields were moderate,
and in the case of chlorobenzenes, no activity was detected.
Finally, the reusability of the catalyst was evaluated by
using the Suzuki coupling of 4-nitrobromobenzene with
phenylboronic acid and the Heck coupling of iodobenzene
with n-butyl acrylate under the optimized condition as the
model reactions. The recycling results for the catalyst are
presented in Table 5. As shown, satisfactory yields were still
observed after four cycles in both Suzuki and Heck coupling
reactions. Also, ICP analysis of the recovered catalyst after
consecutive runs indicated no signiꢁcant change in the Pd
content of the catalyst.
[
16]
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
p-MeO
o-MeO
I
I
I
I
32
48
30
40
32
45
65
35
50
90
27
43
50
80
30
24 h
92
96
94
95
94
82
90
93
90
91
96
92
90
92
94
38
88–90 [17]
Colorless oil [19]
110–112
o-CO H
2
H
p-Me
p-MeO Br
p-NH2
p-CN
p-CHO Br
m-CHO Br
m-CF3
p-NO2
p-Cl
68–70 [13]
46–48 [15]
87–89 [17]
49–50 [14]
84–87 [19]
56–59 [20]
51–53 [18]
Viscous liquid [21]
112–114 [15]
78–79 [22]
69–71 [13]
38–40 [23]
96–98 [24]
Br
0
1
2
3
4
5
6
7
8
9
0
Br
Br
Br
Br
Br
Cl
H
C H SI
4
3
C H Br
10
7
Reaction conditions: aryl halide (1 mmol), phenyl boronic acid
In order to evaluate the eꢂciency of the present catalytic
system, it was compared with other reported Pd catalysts.
As Table 6 shows, the present nanocatalyst gave comparable
(
1.2 mmol), K CO (1.5 mmol), polymer-based nanocatalyst (25 mg)
2 3
and PEG (2 mL)
a
Yields refer to those of pure isolated products
1
3

Transition Metal Chemistry
Scheme 4 Heck coupling of iodobenzene with n-butyl acrylate catalyzed by Fe O @chitosan-bound 2-hydroxynaphthaldehyde Pd complex
3
4
Table 3 Optimization of
reaction parameters for Heck
reaction of iodobenzene with
n-butyl acrylate
Yield (%)a
Entry
Base
Solvent
T (°C)
Catalyst (mg)
Time (min)
1
2
3
4
5
6
7
8
9
0
1
2
3
Et N
H O
120
120
120
120
120
120
120
120
120
120
120
130
140
20
20
20
20
20
20
20
20
–
25
30
25
25
140
80
90
100
5 h
95
90
120
24
65
60
20
85
65
60
–
73
78
45
–
93
94
94
96
3
2
Et N
DMF
DMSO
PEG
3
Et N
3
Et N
3
–
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
NaHCO3
NaOAc
K CO
2
3
Et N
3
1
1
1
1
Et N
3
Et N
3
Et N
45
47
3
Et N
3
Reaction conditions: iodobenzene (1 mmol), n-butyl acrylate (1.2 mmol), base (1.5 mmol) and solvent
(
2 mL)
a
Yields refer to those of pure isolated products
Scheme 5 Heck coupling of aryl iodides/bromides and 2-iodothiophene with n-butyl acrylate catalyzed by Fe O @chitosan-bound 2-hydrox-
3
4
ynaphthaldehyde Pd complex
results to the best of the well-known systems from the
literature.
As a phosphine-free catalyst, the stability of the cata-
lyst against air, moisture and temperature is high. Also, the
catalyst oꢀers advantages such as short reaction times and
excellent yields for Suzuki and Heck reactions. Furthermore,
the catalyst can easily be separated with an external magnet
and reused for four consecutive runs without any signiꢁcant
loss of activity. These promising characteristics suggest that
the catalyst would be suitable for industrial applications.
Conclusions
In conclusion, a magnetically separable nanocatalyst has
been prepared from a chitosan-based Pd complex on Fe O
3
4
nanoparticles.
1
3

Transition Metal Chemistry
Table 4 Heck coupling of aryl iodides/bromides with n-butyl acrylate
Table 5 Reusability of the catalyst in Suzuki–Miyaura and Heck–
catalyzed by Fe O @chitosan-bound 2-hydroxynaphthaldehyde Pd
Mizoroki model reactions
3
4
complex
Entry R
Run
Suzuki reactiona
Heck reactionb
Yield (%)c
X
Time (min) Yield (%)a Mp (°C) [Ref]
Yield (%)c
Time (min)
Time (min)
1
2
3
4
5
6
7
8
9
1
1
1
H
I
I
I
I
I
45
60
53
85
110
94
92
92
90
90
45
45
40
91
70
95
50
Pale yellow liquid [25]
Pale yellow liquid [25]
Pale yellow liquid [25]
Pale yellow liquid [25]
Pale yellow liquid [25]
Pale yellow liquid [25]
Pale yellow liquid [25]
Pale yellow liquid [25]
43–45 [26]
1
2
3
4
43
43
45
45
92
92
90
90
45
45
45
47
94
93
93
90
p-MeO
p-Me
o-Me
o-MeO
H
p-Me
p-MeO Br 130
p-CN Br 100
a
Br 4 h
Br 120
Reaction conditions: nitrobromobenzene (1 mmol), phenyl boronic
acid (1.2 mmol), K CO (1.5 mmol), polymer-based nanocatalyst
2
3
(
25 mg) and PEG (2 mL)
b
Reaction conditions: iodobenzene (1 mmol), n-butyl acrylate
(
1.2 mmol), Et N (1.5 mmol), polymer-based nanocatalyst (20 mg)
3
0
1
2
m-CF3 Br 120
p-NO2 Br 140
Colorless oil [22]
60–63 [26]
Brown oil [27]
and DMF (2 mL)
c
Yields refer to those of pure isolated products
C H SI
80
4
3
Reaction conditions: aryl halide (1 mmol), n-butyl acrylate
(
1.2 mmol), Et N (1.5 mmol), polymer-based nanocatalyst (20 mg)
3
and DMF (2 mL)
a
Yields refer to those of pure isolated products
Table 6 Comparison of the activity of various catalysts in coupling reactions
Entry
Suzuki–Miyaura coupling of p-NO C H Br with PhB(OH)
2
Yield (%)
Time
T (°C)
Solvent/base
Catalytic
system
References
2
6
4
1
2
3
4
5
6
7
8
Fe O @Pd
MeOH/K PO
DMF/KF
45–65
100
75
100
70
100
80
100
18 h
3.5 h
16 h
3 h
1.5 h
12 h
1 h
96
95
90
96
97
91
99
92
[28]
[29]
[30]
[31]
[32]
[33]
[34]
This work
3
4
3
4
MCM-41-Pd Schiꢀ base complex
Biopolymer–metal complex wool–Pd
SMNPs-Salen Pd (II)
HMMS–salpr–Pd
Pd nanoparticles
H O/K CO
2
2
3
DMF-H O/K CO
3
EtOH-H O/K CO
2
2
2
2
3
H O/KOH
2
Fe O /P(GMA-AA-MMA)–Schiꢀ base–Pd
DMF-H O/K CO
PEG/K CO
3
4
2
2
3
Fe O @Pd complex
43 min
3
4
2
3
Heck–Mizoroki coupling of PhI with CH =CHC(O)C H
2
4
9
1
2
3
4
5
6
7
8
HMMS-NH -Pd
Pd@MIL-101
Bio-Pd(0)
SBA-16 supported Pd complex
PDVB-IL-Pd
Si–PNHC–Pd
NMP/K CO
3
130
120
80
125
120
120
140
130
8 h
98
97
97
95
95
95
99
95
[35]
[36]
[37]
[38]
[39]
[40]
[41]
This work
2
2
DMF/K CO :TBAB
120
12 h
240
6 h
2 h
24 h
45 min
2
3
DMF/Na CO
2
3
DMA:H O/Na CO
3
2
2
Solvent free/Et N
3
NMP/K CO
2
3
CB [6] –Pd NPs
DMF/Na CO
2
3
Fe O @Pd complex
DMF/Et N
3
4
3
1
3

Transition Metal Chemistry
Acknowledgements The authors appreciatively acknowledge the fund-
18. Emmanuvel L, Sudalai A (2007) Phosphine ligand and base-free,
Pd- catalyzed oxidative cross-coupling reaction of arylboronic
acids with arylmercuric acetates. Arkivoc 14:126–133
ing support received from the Ilam University, Ilam, Iran, on this work.
1
9. Ma J, Cui X, Zhang B, Song M, Wu Y (2007) Ferrocenylimidazo-
line palladacycles: eꢂcient phosphine-free catalysts for Suzuki-
Miyaura cross-coupling reaction. Tetrahedron 63:5529–5538
References
20. Samarasimhars Eddy M, Prabhu G, Vishwanatha TM, Sureshbabu
VV (2013) PVC-supported palladium nanoparticles: an eꢂcient
catalyst for Suzuki cross-coupling reactions at room temperature.
Synthesis 45:1201–1206
1
2
3
.
.
.
Han FS (2013) Transition-metal-catalyzed Suzuki–Miyaura
cross-coupling reactions: a remarkable advance from palladium
to nickel catalysts. Chem Soc Rev 42:5270–5298
2
1. Ramesh Kumar NSC, Victor Paul Raj I, Sudalai A (2007) Sul-
fonamide- and hydrazine-based palladium catalysts: stable and
eꢂcient catalysts for C–C coupling reactions in aqueous medium.
J Mol Catal A Chem 269:218–244
Polshettiwar V, Decottignies A, Len C, Fihri A (2010) Suzuki–
Miyaura cross-coupling reactions in aqueous media: green and
sustainable syntheses of biaryls. Chemsuschem 3:502–522
Alonso F, Beletskaya IP, Yus M (2008) Non-conventional meth-
odologies for transition-metal catalysed carbon–carbon coupling:
a critical overview. Part 2: the Suzuki reaction. Tetrahedron
2
2
2
2. Peng YY, Liu J, Lei X, Yin Z (2010) Room-temperature highly
eꢂcient Suzuki–Miyaura reactions in water in the presence of
Stilbazo. Green Chem 12:1072–1075
3. Nandurkar NS, Bhanage BM (2008) Palladium bis(2,2,6,6-tetra-
methyl-3,5-heptanedionate) catalyzed Suzuki, Heck, Sonogashira,
and cyanation reactions. Tetrahedron 64:3655–3660
6
4:3047–3101
4
5
6
7
.
.
.
.
Martin R, Buchwald SL (2008) Palladium-catalyzed Suzuki–
Miyaura cross-coupling reactions employing dialkylbiaryl phos-
phine ligands. Acc Chem Res 41:1461–1473
4. Baia L, Wanga JX (2007) Reusable, polymer-supported, palla-
dium-catalyzed, atom- eꢂcient coupling reaction of aryl halides
with sodium tetraphenylborate in water by focused microwave
irradiation. Adv Synth Catal 350:315–320
Mondal J, Modak A, Bhaumik A (2011) One-pot eꢂcient Heck
coupling in water catalyzed by palladium nanoparticles tethered
into mesoporous organic polymer. J Mol Catal A Chem 350:40–48
Trzeciak AM, Ziołkowski JJ (2007) Monomolecular, nanosized
and heterogenized palladium catalysts for the Heck reaction.
Coord Chem Rev 251:1281–1293
2
2
5. Xu Q, Duan WL, Lei ZY, Zhu ZB, Shi M (2005) A novel cis-
chelated Pd(II)–NHC complex for catalyzing Suzuki and Heck-
type cross-coupling reactions. Tetrahedron 61:11225–11229
6. Aksın Ö, Türkmen H, Artok L, Ҫetinkaya B, Ni Ch, Büyük-
güngör O, Özkal E (2006) Compromise between conju-
Kalbasi RJ, Mosaddegh N, Abbaspourrad A (2012) Palladium
nanoparticles supported on a poly(N-vinyl-2-pyrrolidone)-modi-
5
gation length and charge-transfer in nonlinear optical η -
ꢁ
ed mesoporous carbon nanocage as a novel heterogeneous cata-
monocyclopentadienyliron(II) complexes with substituted
oligo-thiophene nitrile ligands: synthesis, electrochemical studies
and ꢁrst hyperpolarizabilities. J Organomet Chem 691:3027–3041
7. Mino T, Shibuya M, Suzuki S, Hirai K, Sakamoto M, Fujita T
lyst for the Heck reaction in water. Tetrahedron Lett 53:3763–3766
Polshettiwar V, Molnar A (2007) Silica-supported Pd catalysts for
Heck coupling reactions. Tetrahedron 63:6949–6976
8
9
.
.
2
2
2
Phan NTS, Van Der Sluys M, Jones CW (2006) On the nature
of the active species in palladium catalyzed Mizoroki–Heck and
Suzuki–Miyaura couplings–homogeneous or heterogeneous catal-
ysis, a critical review. Adv Synth Catal 348:609–679
(
2012) Palladium-catalyzed Mizoroki–Heck type reaction with
aryl trialkoxysilanes using hydrazone ligands. Tetrahedron
8:429–432
8. Amali AJ, Rana RK (2009) Stabilisation of Pd(0) on surface
6
1
1
0. Cho JH, Shaughnessy KH (2011) Aqueous-phase Heck coupling
of 5-iodouridine and alkenes under phosphine-free conditions.
Synlett. https://doi.org/10.1055/s-0031-1289886
functionalised Fe O nanoparticles: magnetically recoverable and
3
4
stable recyclable catalyst for hydrogenation and Suzuki–Miyaura
reactions. Green Chem 11:1781–1786
1. Polshettiwar V, Varma RS (2009) Nanoparticle-supported and
magnetically recoverable palladium (Pd) catalyst: a selective and
sustainable oxidation protocol with high turnover number. Org
Biomol Chem 7:37–40
9. Dhara K, Sarkar K, Srimani D, Saha SK, Chattopadhyaye P, Bhau-
mik A (2010) A new functionalized mesoporous matrix supported
Pd(II)-Schiꢀ base complex: an eꢂcient catalyst for the Suzuki–
Miyaura coupling reaction. Dalton Trans 39:6395–6402
0. Ma H, Cao W, Bao Zh, Lei Z (2012) Biopolymer–metal complex
wool–Pd as a highly active catalyst for Suzuki reaction in water.
Catal Sci Technol 2:2291–2296
1
1
2. Safari J, Javadian L (2014) Chitosan decorated Fe O nanoparti-
3
4
3
3
3
cles as a magnetic catalyst in the synthesis of phenytoin deriva-
tives. RSC Adv 4:48973–48979
3. Cho SD, Kim HK, Yim HS, Kim MR, Lee JK, Kim JJ, Yoon YJ
1. Jin X, Zhang K, Sun J, Wang J, Dong Z, Li R (2012) Magnetite
nanoparticles immobilized Salen Pd (II) as a green catalyst for
Suzuki reaction. Catal Commun 26:199–203
(
2007) Suzuki–Miyaura coupling reaction of aryl chlorides using
di(2,6 dimethylmorpholino)phenylphosphine as ligand. Tetrahe-
dron 63:1345–1352
2. Liu H, Wang P, Yang H, Niu J, Ma J (2015) Palladium sup-
ported on hollow magnetic mesoporous spheres: a recoverable
catalyst for hydrogenation and Suzuki reaction. New J Chem
1
4. Alacid E, Nájera C (2008) First cross-coupling reaction of potas-
sium aryltriꢃuoroborates with organic chlorides in aqueous media
catalyzed by an oxime-derived palladacycle. Org Lett 10:5011–5014
5. Masllorens J, Gonzalez I, Roglans A (2007) Recoverable homoge-
neous palladium(0) catalyst for cross-coupling reactions of aren-
ediazonium salts with potassium organotriꢃuoroborates: detection
of catalytic intermediates by electrospray ionization mass spec-
trometry. Eur J Org Chem 1:158–166
3
9:4343–4350
1
3
3
3
3. Nasrollahzadeh M, Sajadi SM, Maham M (2015) Green synthesis
of palladium nanoparticles using Hippophaerhamnoides Linn leaf
extract and their catalytic activity for the Suzuki–Miyaura cou-
pling in water. J Mol Catal A Chem 396:297–303
4. Yuan D, Chen L, Yuan L, Liao S, Yang M, Zhang Q (2016) Super-
paramagnetic polymer composite microspheres supported Schiꢀ
base palladium complex: an eꢂcient and reusable catalyst for the
Suzuki coupling reactions. Chem Eng J 287:241–251
1
6. Stevens PD, Fan J, Gardimalla HMR, Yen M, Gao Y (2005)
Superparamagnetic nanoparticle-supported catalysis of Suzuki
cross-coupling reactions. Org Lett 7:2085–2088
1
7. Lü B, Fu C, Ma S (2010) Application of a readily available and air
5. Wang P, Liu H, Liu M, Li R, Ma J (2014) Immobilized Pd com-
plexes over HMMS as catalysts for Heck cross-coupling and selec-
tive hydrogenation reactions. New J Chem 38:1138–1143
stable monophosphine HBF salt for the Suzuki coupling reaction
4
of aryl or 1-alkenyl chlorides. Tetrahedron Lett 51:1284–1286
1
3

Transition Metal Chemistry
3
3
3
6. Shang N, Gao S, Zhou X, Feng C, Wang Z, Wang C (2014) Pal-
ladium nanoparticles encapsulated inside the pores of a metal–
organic framework as a highly active catalyst for carbon–carbon
cross-coupling. RSC Adv 4:54487–54493
39. Liu G, Hou M, Song J, Jiang T, Fan H, Zhang Z, Han B (2010)
Immobilization of Pd nanoparticles with functional ionic liquid
grafted onto cross-linked polymer for solvent-free Heck reaction.
Green Chem 12:65–69
7. Søbjerg LS, Gauthier D, Lindhardt AT, Bunge M, Finster K,
Meyer RL, Skrydstrup T (2009) Bio-supported palladium nano-
particles as a catalyst for Suzuki–Miyaura and Mizoroki–Heck
reactions. Green Chem 11:2041–2046
40. Tamami B, Farjadian F, Ghasemi S, Allahyari H (2013) Synthesis
and applications of polymeric N-heterocyclic carbene palladium
complex-grafted silica as a novel recyclable nano-catalyst for Heck
and Sonogashira coupling reactions. New J Chem 37:2011–2018
41. Cao M, Wei Y, Gao S, Cao R (2012) Synthesis of palladium nano-
catalysts with cucurbit[n]uril as both a protecting agent and a sup-
port for Suzuki and Heck reactions. Catal Sci Technol 2:156–163
8. Sarkar SM, Rahman ML, Yusoꢀ MM (2015) Heck, Suzuki and
Sonogashira cross-coupling reactions using ppm level of SBA-16
supported Pd-complex. New J Chem 39:3564–3570
1
3