Synthesis and characterization of a novel magnetic nano-palladium Schiff base complex: application in cross-coupling reactions

Article abstract of DOI:10.1002/aoc.3477

A novel and task-specific nano-magnetic Schiff base ligand with phosphate spacer using 2-aminoethyl dihydrogen phosphate instead of usual coating agents, i.e. tetraethoxysilane and 3-aminopropyltriethoxysilane, for coating of nano-magnetic Fe₃O₄ is introduced. The nano-magnetic Schiff base ligand with phosphate spacer as a novel catalyst was synthesized and fully characterized using infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies, thermogravimetry, derivative thermogravimetry, vibrating sample magnetometry, atomic force microscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. The resulting task-specific nano-magnetic Schiff base ligand with phosphate spacer was successfully employed as a magnetite Pd nanoparticle-supported catalyst for Sonogashira and Mizoroki–Heck C–C coupling reactions. To the best of our knowledge, this is the first report of the synthesis and applications of magnetic nanoparticles of Fe₃O₄@O₂PO₂(CH₂)₂NH₂ as a suitable spacer for the preparation of a designable Schiff base ligand and its corresponding Pd complex. So the present work can open up a new and promising insight in the course of rational design, synthesis and applications of various task-specific magnetic nanoparticle complexes.

Full text of DOI:10.1002/aoc.3477

Full paper
Received: 24 January 2016
Revised: 21 February 2016
Accepted: 23 February 2016
Published online in Wiley Online Library
(wileyonlinelibrary.com) DOI 10.1002/aoc.3477
Synthesis and characterization of a novel
magnetic nano-palladium Schiff base complex:
application in cross-coupling reactions
Millad Aghayeea, Mohammad Ali Zolfigolb*, Hassan Keypoura, Meysam Yarieb
and Leila Mohammadib
A novel and task-specific nano-magnetic Schiff base ligand with phosphate spacer using 2-aminoethyl dihydrogen phosphate in-
stead of usual coating agents, i.e. tetraethoxysilane and 3-aminopropyltriethoxysilane, for coating of nano-magnetic Fe3O4 is in-
troduced. The nano-magnetic Schiff base ligand with phosphate spacer as a novel catalyst was synthesized and fully characterized
using infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies, thermogravimetry, derivative
thermogravimetry, vibrating sample magnetometry, atomic force microscopy, X-ray photoelectron spectroscopy and energy-
dispersive X-ray spectroscopy. The resulting task-specific nano-magnetic Schiff base ligand with phosphate spacer was success-
fully employed as a magnetite Pd nanoparticle-supported catalyst for Sonogashira and Mizoroki–Heck C–C coupling reactions.
To the best of our knowledge, this is the first report of the synthesis and applications of magnetic nanoparticles of
Fe3O4@O2PO2(CH2)2NH2 as a suitable spacer for the preparation of a designable Schiff base ligand and its corresponding Pd com-
plex. So the present work can open up a new and promising insight in the course of rational design, synthesis and applications of
various task-specific magnetic nanoparticle complexes. Copyright © 2016 John Wiley & Sons, Ltd.
Additional supporting information may be found in the online version of this article at the publisher’s web site.
Keywords: task-specific nano-magnetic Schiff base ligand; 2-aminoethyl dihydrogen phosphate; Sonogashira and Mizoroki–Heck C–C
coupling reactions; magnetite Pd nanoparticle-supported catalyst
near homogeneous and heterogeneous catalytic systems from ac-
tivity and selectivity outlooks, but the easy separation and recovery
Introduction
Nowadays, novel approaches focus on sustainable development of
highly selective nanostructured catalysts by designing and apply-
ing suitable catalytic species and central cores.[1] There are exten-
sive reports wherein silica derivatives have been employed as
coating agents for the synthesis of nano-magnetic catalysts,
possessing several outstanding features such as high activity and
selectivity, excellent stability, efficient recovery and recyclability.2
Therefore, knowledge-based design, synthesis and applications
of powerful, recyclable and reusable nano-magnetic catalysts are
in demand. Literature surveys show that heterogeneous catalysts
in chemical processes have attracted a great deal of attention due
to their merits such as easy separation from the reaction mixture
and good reusability compared to homogeneous catalytic systems.
One important issue that has to be considered in terms of using
heterogeneous catalytic systems compared with homogeneous
ones is the low activity and selectivity because of the low surface
area. Also, in the case of immobilization of a catalytically active spe-
cies on a suitable support, this problem is more serious. In this case,
the active sites in a supported system, due to the steric hindrance of
the bulky support, are not as approachable as those in a homoge-
neous equivalent. Combination of nanotechnology and heteroge-
neous catalytic systems can overcome the drawbacks connected
with bulky supports by miniaturizing the size of the support. This
approach leads to an increase of the ratio of surface to volume
and consequently can multiply the interactions of surface and reac-
tants. Notwithstanding that, nano-chemistry technology can draw
of the catalyst are still major restrictions for nanomaterials due to
their very small dimensions. The knowledge-based development
of the science of catalysts leads chemists to create and use mag-
netic nanoparticles as excellent alternatives which can be easily
separated from the reaction mixture by applying a simple external
magnet. Also, the magnetization of common nano-solid supports is
an excellent method for overcoming the difficulty in the separation
of catalysts from reaction mixtures. The combination of heteroge-
neous properties, nano-chemistry technology and magnetic solid
supports can create a new class of heterogeneous recoverable
and reusable catalytic systems that have the benefits of homoge-
neous catalysts, such as high activity and selectivity.[2–4]
The Sonogashira cross-coupling reaction which constructs C
(sp2)–C(sp) bonds leading to arylalkynes and conjugated enynes
using homogeneous and heterogeneous palladium catalysts in
the presence or absence of Cu(I) as a co-catalyst[5–9] is a straightfor-
ward route to pharmaceutical and biologically active molecules
such as tazarotene (1)[10] for the treatment of psoriasis and acne
and altinicline (2)[11] for the therapy of Parkinson’s disease,
*
Correspondence to: Mohammad Ali Zolfigol, Faculty of Chemistry, Bu-Ali Sina
University, Hamedan, 6517838683, Iran. E-mail: zolfi@basu.ac.ir; mzolfigol@yahoo.com
a Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174, Iran
b Faculty of Chemistry, Bu-Ali Sina University, Hamedan 6517838683, Iran
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.

M. Aghayee et al.
Alzheimer’s disease, Tourette syndrome, schizophrenia and atten-
tion deficit hyperactivity disorder.
The Mizoroki–Heck reaction is a very powerful and effective pro-
cedure for the preparation of substituted alkenes through the reac-
tion of unsaturated halides, triflates and diazoniums with an alkene
in the presence of a suitable base and palladium catalyst or palla-
dium nanomaterial-based catalyst.[12–14] Also, the resulting prod-
ucts from the Heck reaction have shown a wide variety of
applications in the pharmaceutical industry.[15]
Scheme 2. Applicability of the novel Pd-based catalyst in C–C coupling
reactions.
Results and discussion
The structure of the nano-magnetic Schiff base ligand with phos-
phate spacer as a novel catalyst was fully investigated using various
methods such as: infrared (IR) spectroscopy, X-ray diffraction (XRD),
scanning electron microscopy (SEM), transmission electron micros-
copy (TEM), thermogravimetry (TG), vibrating sample magnetome-
try (VSM), atomic force microscopy (AFM) and energy-dispersive
X-ray (EDX) analysis.
The broad absorption band in the region of about 3000–
3600 cmꢀ1 in the IR spectra can be attributed to the overlapping of
uncoated O–H and NH2 group stretching modes of compound II,
and also the P¼O stretching mode is verified by observation of a peak
at 1142 cmꢀ1 (Fig. 1(b)). The reaction of compound II and dialdehyde
2-Aminoethyl dihydrogen phosphate, aminoethyl phosphate or
phosphorylethanolamine (with two pKa values of 5.61 and 10.39) is
an ethanolamine derivative that is used to build up sphingomyelins
(sphingomyelin is a type of sphingolipid that can be found in animal
cell membranes, particularly in the membranous myelin sheath that
surrounds some nerve cell axons). Also, it has been reported that syn-
thetic phosphorylethanolamine can act as a treatment for Ehrlich as-
cites tumour cells in cancer therapy.[16,17] Very recently, Zarghani and
Akhlaghinia reported Cu(II) immobilized on aminated ferrite nanopar-
ticles using 2-aminoethyl dihydrogen phosphate (Fe3O4@AEPH2-CuII)
for conversion of aldoximes to nitriles.[18] They have also reported a
sulfonated nanohydroxyapatite functionalized with 2-aminoethyl
dihydrogen phosphate (HAP@AEPH2-SO3H) as a new green, recycla-
ble, solid acid catalyst for the one-pot synthesis of 4,4′-(aryl methy-
lene)bis(3-methyl-1H-pyrazol-5-ol)s.[19] Also, Yilmaz and co-workers
reported the synthesis of novel calixarene-functionalized iron oxide
magnetite nanoparticles and investigated the extraction abilities of
these extractants for the removal of dichromate/arsenate ions from
water.[20]
As is known, 2-aminoethyl dihydrogen phosphate has a dual role: it
can act as both spacer and coating agent in the synthetic processes of
our designed magnetic nanocatalysts. Thus, we do not need any use
of silica coating agent for the covering of central magnetic Fe3O4
nanoparticles. In continuation of our knowledge-based development
of task-specific nano-magnetic catalysts,[21] herein, we report the
preparation of a novel task-specific nano-magnetic Schiff base ligand
with phosphate spacer and the applications of its resulting Pd nano-
magnetic heterogeneous catalyst in the Sonogashira and Mizoroki–
Heck reactions (Schemes 1 and 2).
Figure 1. IR spectrum of the catalyst (c) in comparison with the IR spectra
of compound II (b) and Fe3O4 nanoparticles (a).
Scheme 1. Preparation of novel task-specific nano-magnetic Schiff base
ligand with phosphate spacer and its Pd nano-magnetic heterogeneous
catalyst.
Figure 2. EDX analysis of the catalyst.
wileyonlinelibrary.com/journal/aoc
Copyright © 2016 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. (2016)

Task-specific nano-magnetic Schiff base ligand with phosphate spacer
III and the formation of the catalyst are confirmed by the C¼N band
at 1625 cmꢀ1 in the IR spectrum of catalyst V (Fig. 1(c)).
The results of EDX spectroscopy confirm all the expected ele-
ments, namely carbon, nitrogen, oxygen, palladium, iron and phos-
phorus, as shown in Fig. 2. Moreover, the SEM-coupled EDX data for
the new catalyst imply that it consists of C (0.04), N (3.25), Fe (65.60),
O (24.17), Pd (6.59) and P (0.34).
Using VSM analysis, the magnetic behaviour of the novel
nanocatalyst in comparison with Fe3O4 nanoparticles was studied,
as depicted in Fig. 3. According to the resulting magnetization
curves, the saturation of the prepared catalyst reduces to
64 emu gꢀ1 from 70emu gꢀ1. This reduction in saturation arises
from the surface coating of the Fe3O4 nanoparticles in the synthetic
pathway of the novel catalyst. It is worth mentioning that due to
the direct connection of the Pd complex to the surface of the
Fe3O4 nanoparticles, the magnetic property of the new catalyst
not very much reduced in comparison with other core–shell
catalysts,[2–4] and this merit guarantees very facile and efficient sep-
aration of the catalyst from the reaction mixture due to the very
good magnetic property.
TEM images of the new catalyst were recorded and are shown in
Fig. 4. According to the TEM images, the sizes of the catalyst parti-
cles are less than 50 nm.
In addition to the TEM images (Fig. 4), in attempting to confirm of
the size and morphology of the prepared catalyst, SEM images
were recorded and are shown in Fig. 5. It can be inferred from the
SEM images that the size of the catalyst particles is in the
nanometre range in good accordance with the TEM images.
Figure 4. TEM images of the new catalyst.
The XRD pattern of the synthesized catalyst in comparison with
those of Fe3O4 nanoparticles and compound II was investigated
as depicted in Fig. 6. It can be concluded from the XRD patterns that
the addition of each layer onto the surface of the Fe3O4 nanoparti-
cles changes the corresponding XRD pattern compared with previ-
ous stage, being an indication of the preparation of the novel
catalyst. The XRD pattern of the novel catalyst shows that it has a
crystalline nature with diffraction lines at 2θ ≈ 9.10°, 16.70°, 22.20°,
22.80°, 24.90°, 30.70°, 35.50°, 36.00°, 53.50°, 57.30° and 62.90°. In ad-
dition, the XRD data, including 2θ value, peak width, size of particles
and interplanar distance, were extracted and are summarized in
Table 1. It can be inferred from the extracted XRD data, based on
the Scherrer equation D = Kλ/(β cos θ), where λ is the X-ray wave-
length, K the Scherrer constant, β the peak width of half maximum
Figure 3. VSM analysis of novel catalyst and Fe3O4 nanoparticles.
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

M. Aghayee et al.
Table 1. XRD data for the prepared catalyst
Entry
2θ (°)
Peak width
(FWHM) (°)
Size (nm)
Interplaner
distance (nm)
1
9.10
0.50
0.25
0.34
0.24
0.36
0.47
0.30
0.34
0.16
0.31
0.33
15.94
32.12
23.87
33.77
22.60
17.53
27.81
24.57
55.61
29.20
28.22
0.158656
0.530233
0.799912
0.015219
0.357164
0.290879
0.251885
0.249178
0.171073
0.087742
0.147579
2
16.70
22.20
22.80
24.90
30.70
35.60
36.00
53.50
57.30
62.90
3
4
5
6
7
8
9
10
11
and θ the Bragg diffraction angle, that the particle size of the cata-
lyst is in the nanometre range of about 15.94–55.61 nm. It is note-
worthy that the resulting data from the XRD pattern are in good
agreement with the results from TEM and SEM images (Figs. 4
and 5).
Also, for the investigation of the surface topography and analysis
of the surface at a high resolution of the novel Pd-based catalyst, a
three-dimensional AFM image was obtained, as portrayed in Fig. 7.
The three-dimensional 5μm × 5 μm skeleton shows that the pre-
pared nanocatalyst has a disturbed surface structure.
In order to determine the oxidation state of Pd in the complex, X-
ray photoelectron spectroscopy (XPS) was conducted and the re-
sults are portrayed in Fig. 8. The binding energy pattern reveals
Figure 7. Three-dimensional AFM image of the surface of the Pd-based
catalyst.
Figure 5. SEM images of the prepared catalyst.
Figure 6. XRD pattern of synthesized catalyst in comparison with the
patterns of Fe3O4 nanoparticles and compound II.
Figure 8. XPS spectra of the catalyst: Pd(0).
wileyonlinelibrary.com/journal/aoc
Copyright © 2016 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. (2016)

Task-specific nano-magnetic Schiff base ligand with phosphate spacer
two peaks at 341.9 eV (3d5/2) and 345.4 eV (3d3/2) which can be at-
tributed to the Pd(0) oxidation state.
Table 3. Applicability of novel catalyst for a range of substrates in
Sonogashira reaction
After the structural verification of the prepared catalyst with the
aforementioned techniques, the applicability of the catalyst was in-
vestigated in the Sonogashira and Mizoroki–Heck reactions
(Scheme 2). In the first place, the reaction of phenylacetylene and
bromobenzene was chosen as a test reaction. In order to determine
the best experimental conditions for the Sonogashira reaction, var-
ious solvents, bases and loads of novel catalyst were checked and
the resulting data are summarized in Table 2. It can be deduced
from Table 2 that the optimized conditions for the Sonogashira re-
action are when the reaction is performed using water as a green
solvent, K2CO3 as a base and utilizing a catalytic amount of pre-
pared catalyst (Table 2, entry 2).
Entry
Aryl halide
Alkyne
Product Time
(min)
Yield
(%)a
1
2
3
1-Bromobenzene Phenylacetylene 2a
40
40
42
92
95
88
1-Iodobenzene
1-Bromo-4-
Phenylacetylene 2a
Phenylacetylene 2b
nitrobenzene
4
2-Bromonaphthalene Phenylacetylene 2c
54
90
80
90
85
83
45
40
88
91
5b 1,4-Dibromobenzene Phenylacetylene 2d
6
7
8
1,4-Dibromobenzene Phenylacetylene 2e
1-Bromobenzene
1-Iodobenzene
1-Heptyne
1-Heptyne
2f
2f
aIsolated yields.
To investigate the generality and the vesatility of the determined
optimized reaction conditions, according to Table 2 for the
Sonogashira cross-coupling reaction, the extent of the reaction
was widened to other aryl halides as summarized in Table 3. The
resulting data show that the reported method is applicable to other
substrates and substituents with good to high yields being
achieved in comparatively short reaction times.
In another experiment, the applicability of the prepared novel
catalyst was probed in the Mizoroki–Heck reaction. In order to
achieve the best experimental conditions for the reaction, the reac-
tion between bromobenzene and styrene was chosen as a test re-
action and the effect of various solvents, bases and loads of new
catalyst was scrutinized. According to the obtained data as summa-
rized in Table 4, the optimized conditions for the Mizoroki–Heck re-
action in these surveys are when the reaction is carried out in
acetonitrile as a solvent with K2CO3 as base in the presence of the
magnetically separable novel Pd-based catalyst (Table 4, entry 3).
In the case of the Mizoroki–Heck reaction, similar to the
Sonogashira reaction, the versatility and the generality of the opti-
mized conditions were checked for the reaction of various aryl
bReaction performed with two equivalents of phenylacetylene in the
presence of 10 mg of catalyst.
halides with styrene. The desired products are obtained in good
to high yields in appropriate reaction times as summarized in
Table 5.
Also, the possibility of recycling the prepared catalyst was ex-
plored for both types of cross-coupling reactions for nine runs. After
the completion of the each run the catalyst was separated from the
reaction mixture by applying a simple magnet and washed repeat-
edly with EtOH and recovered. In the case of the Sonogashira reac-
tion, the re-use of the catalyst was examined for the reaction
between phenylacetylene and bromobenzene under the optimized
conditions in 40 min. In the case of the Mizoroki–Heck reaction, the
reaction between styrene and bromobenzene was chosen as a
model for the recycling test under the optimized conditions in
Table 4. Optimization of reaction conditions for Mizoroki–Heck
reactiona
Table 2. Optimization of reaction conditions for Sonogashira reactiona
Entry
Catalyst
amount (mg)
Base
Solventb
Reaction
time (min)
Yield (%)c
Entry
Catalyst
amount (mg)
Base
Solventb Reaction Yield (%)c
time (h)
1
5
5
5
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
Na2CO3
NaOH
Et3N
DMF
H2O
58
40
45
48
48
50
45
52
60
60
60
47
40
40
80
92
88
85
83
82
88
82
78
70
68
85
92
93
1
5
5
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
Na2CO3
NaOH
Et3N
DMF
H2O
3
3
88
85
92
80
82
78
89
78
75
65
60
85
92
93
2
2
3
CH3CN
EtOH
MeOH
CH2Cl2
H2O
3
5
5
CH3CN
EtOH
3
3
4
5
4
5
5
5
5
MeOH
CH2Cl2
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
3
6
5
6
5
3
7
5
7
5
3
8
5
H2O
8
5
3
9
5
H2O
9
5
3
10
11
12
13
14
5
NH3
H2O
10
11
12
13
14
5
NH3
3
5
DABCO
K2CO3
K2CO3
K2CO3
H2O
5
DABCO
K2CO3
K2CO3
K2CO3
3
3
H2O
3
3
7
H2O
7
3
10
H2O
10
2.5
aReaction conditions: phenylacetylene (1 mmol) and bromobenzene
(1 mmol).
aReaction conditions: styrene (1 mmol) and bromobenzene (1 mmol).
bReflux.
bReflux.
cIsolated yield.
cIsolated yield.
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

M. Aghayee et al.
Table 5. Versatility of the new catalyst in Mizoroki–Heck reaction
Experimental
Entry
Aryl Halide
Product Reaction Yield
General
time (h)
(%)a
All chemicals were purchased from Fluka and Merck. The known
products were identified by comparison of their physical properties
and spectral data with those reported for authentic samples in the
literature. Reaction progress and purity determination of the com-
pounds were checked by TLC using silica gel SIL G/UV 254 plates. 1H
NMR and 13C NMR spectra were recorded with a Bruker spectrom-
eter. Melting points were recorded with a Buchi B-545 apparatus in
open capillary tubes.
1
2
3
4
5
6
7
8b
1-Bromobenzene
1-Iodobenzene
3a
3a
3b
3c
3
2
92
95
90
88
91
86
45
55
1-Bromo-4-nitrobenzene
1-Bromo-4-methylbenzene
1-Bromo-4-methoxybenzene
2-Bromonaphthalene
1,4-Dibromobenzene
1,4-Dibromobenzene
3
3
3d
3e
3f
2
20
4
3 g
4
aIsolated yields.
Preparation of novel Pd-based catalyst
bReaction performed with two equivalents of styrene in the presence
Initially, Fe3O4 nanoparticles (I) were synthesized according to pro-
cedures reported in the literature.[21,22] In the second step, 1 g of I
was added to 50 ml of a mixture of ethanol and deionized water.
To the resulting mixture was added 2-aminoethyl dihydrogen
phosphate (12 mmol, 1.69 g) dissolved in 20 ml of deionized water.
The solution was stirred for 12 h at room temperature. Then, the
resulting 2-aminoethyl dihydrogen phosphate-functionalized
Fe3O4 nanoparticles (II) were washed repeatedly with ethanol and
deionized water and collected with a magnet and air-dried. To a
mixture of II in 20 ml of methanol was added dialdehyde III
(6mmol, 1.62 g) followed by refluxing for 24 h. In the last step, the
synthesized nanoparticles (IV) were added to a mixture of PdCl2 dis-
persed in toluene as solvent and stirred vigorously for 24 h under
nitrogen atmosphere at 70 °C. Finally, the resulting nano-magnetic
Schiff base Pd complex catalyst with 2-aminoethyl phosphate
spacers (V) was washed with ethanol and collected with an external
magnet and air-dried (Scheme 1).
of 10 mg of catalyst.
Figure 9. Recyclability of the prepared catalyst in both cases of cross-
coupling reactions.
General procedure for sonogashira reaction
To a round-bottom flask containing aryl halide (1mmol) and
phenylacetylene or 1-heptyne (1mmol) were added K2CO3
(1.5mmol, 0.207 g) as a base, 5 ml of water as a solvent and 5 mg
(0.002 mmol of Pd) of catalyst V. The resulting mixture was stirred
vigorously at 90 °C for appropriate times as given in Table 2. After
the completion of the reactions as monitored by TLC using n-
hexane as eluent, the reaction mixture was quenched to ambient
temperature. Then, 25 ml of Et2O was added to the solution and
the organic layer was separated using a decanter and dried with
Na2SO4. Finally, the crude products were purified with preparative
TLC in high to excellent yields as summarized in Table 2. The pre-
pared catalyst was separated by applying an external magnet and
washed repeatedly with EtOH and recovered for the next run.
3 h. The data obtained are depicted in Fig. 9. Regardless of the type
of coupling, the results indicate that the catalyst can be utilized sev-
eral times (9 runs) without any significant loss of its initial catalytic
activity which can be ascribed to the high stability of the prepared
catalyst.
Conclusions
In summary, we have developed a novel task-specific nano-
magnetic Schiff base ligand with phosphate spacer using 2-
aminoethyl dihydrogen phosphate for coating of magnetic
Fe3O4 nanoparticles. The structure of the resulting Pd-based
nano-magnetic catalyst was fully confirmed using IR spectros-
copy, XRD, SEM, TEM, TG, VSM, AFM, XPS and EDX analysis. The
prepared task-specific nano-magnetic Schiff base ligand with
phosphate spacer was successfully used as a magnetite Pd
nanoparticle-supported catalyst for the Sonogashira and
Mizoroki–Heck C–C coupling reactions. To the best of our knowl-
edge, this is the first report of the synthesis and applications of
magnetic nanoparticles of Fe3O4@O2PO2(CH2)2NH2 as a suitable
spacer for the preparation of designable Schiff base ligand and
its corresponding Pd complex. So the present work can open
up a new and promising insight in the course of rational design,
synthesis and applications of various task-specific magnetic
nanoparticle complexes.
General procedure for Mizoroki–Heck reaction
To a mixture of aryl halide (1mmol) and styrene (1mmol, 0.104 g)
were added K2CO3 (1.5mmol, 0.207 g) as a base and 5 ml of CH3CN
as a solvent in a round-bottom flask, to which was added 5 mg of
Pd-based catalyst (0.002 mmol of Pd). The resulting mixture was
refluxed for appropriate times as given in Table 4. When the reac-
tion was completed, as monitored by TLC, the mixture was
quenched to ambient temperature and 25ml of n-hexane was
added to the solution. The organic layer was separated and dried
with Na2SO4. After evaporation of the solvent, the pure product
was obtained in high to excellent yields. The catalyst was separated
by applying an external magnet and washed repeatedly with EtOH
and recovered for the next run.
wileyonlinelibrary.com/journal/aoc
Copyright © 2016 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. (2016)

Task-specific nano-magnetic Schiff base ligand with phosphate spacer
Chem. 2012, 77, 2798; c) R. Chinchilla, C. Najera, Chem. Soc.
Rev. 2011, 40, 5084; d) R. Chinchilla, C. Najera, Chem. Rev.
2007, 107, 874.
Acknowledgements
We thank Bu-Ali Sina University and Iran National Science Founda-
tion (INSF) for financial support (Grant of Allameh Tabataba’i’s
Award) of our research group.
[10] S. Frigoli, C. Fuganti, L. Malpezzi, S. Serra, Org. Process Res. Dev. 2005, 9,
646.
[11] A. O. King, N. Yasuda, Top. Organometal. Chem. 2004, 6, 205.
[12] L. Yin, J. Liebscher, Chem. Rev. 2007, 107, 133.
[13] R. F. Heck, J. P. Nolley, J. Org. Chem. 1972, 37, 2320.
[14] T. Mizoroki, K. Mori, A. Ozaki, Bull. Chem. Soc. Jpn. 1971, 44, 581.
[15] A. F. Littke, G. C. Fu, Angew. Chem. Int. Ed. Engl. 2002, 41, 4176.
[16] A. T. Myller, J. J. Karhe, T. T. Pakkanen, Appl. Surf. Sci. 2010, 257, 1616.
[17] A. K. Ferreira, R. Meneguel, A. Pereira, O. M. R. Filho, G. O. Chierice,
D. A. Maria, Anticancer Res 2012, 32, 95.
[18] M. Zarghani, B. Akhlaghinia, Appl. Organometal. Chem. 2015, 29, 683.
[19] M. Zarghani, B. Akhlaghinia, RSC Adv. 2015, 5, 87769.
[20] S. Sayin, F. Ozcan, M. Yilmaz, Mater. Sci. Eng. C 2013, 33, 2433.
[21] a) T. Azadbakht, M. A. Zolfigol, R. Azadbakht, V. Khakizadeh, D. Perrin,
New J. Chem. 2015, 39, 439; b) M. A. Zolfigol, T. Azadbkht,
V. Khakizadeh, R. Nejatyami, D. Perrin, RSC. Adv. 2014, 4, 40036; c)
M. A. Zolfigol, V. Khakyzadeh, A. R. Moosavi-Zare, A. Rostami, A. Zare,
N. Iranpoor, M. H. Beyzavie, R. Luque, Green Chem. 2013, 15, 2132; d)
N. Koukabi, E. Kolvari, A. Khazaei, M. A. Zolfigol,
B. Shirmardi-Shaghasemi, H. R. Khavasi, Chem. Commun. 2011, 47,
9230; e) M. A. Zolfigol, M. Yarie, RSC Adv. 2015, 5, 103617; f)
M. Safaiee, M. A. Zolfigol, F. Afsharnadery, S. Baghery, RSC Adv. 2015,
5, 102340.
References
[1] R. K. Sharma, S. Sharma, S. Dutta, R. Zboril, M. B. Gawande, Green Chem.
2015, 17, 3207.
[2] a) S. Rostamnia, E. Doustkhaha, J. Mol. Catal. A 2016, 411, 317; b)
S. Rostamnia, E. Doustkhaha, Synlett 2015, 26, 1345.
[3] B. Karimi, F. Mansouri, H. M. Mirzaei, ChemCatChem 2015, 7, 1736.
[4] a) T. Cheng, D. Zhang, H. Li, G. Liu, Green Chem. 2014, 16, 3401; b)
M. B. Gawande, R. Luque, R. Zboril, ChemCatChem 2014, 6, 3312; c)
D. Zhang, C. Zhou, Z. Sun, L. Wu, C. Tunga, T. Zhang, Nanoscale 2012,
4, 6244.
[5] a) K. Sonogashira, Y. Tohda, N. Hagihara, Tetrahedron Lett. 1975, 16,
4467; b) H. A. Dieck, F. R. Heck, J. Organometal. Chem. 1975, 93, 259;
c) L. Cassar, J. Organometal. Chem. 1975, 93, 253.
[6] a) M. Kotora, T. Takahashi, in Handbook of Organopalladium Chemistry
for Organic Synthesis (Ed: E.-I. Negishi), John Wiley, New York, 2003, p.
973; b) P. Siemsen, R. C. Livingston, F. Diederich, Angew. Chem. Int.
Ed. 2000, 39, 2632.
[7] a) D. Gelman, S. L. Buchwald, Angew. Chem. Int. Ed. 2003, 42, 5993; b)
J. Liu, J. Chen, C. Xia, J. Catal. 2008, 253, 50; c) A. Corma, H. García,
A. Primo, J. Catal. 2006, 241, 123; d) A. Corma, H. García, A. Leyva,
J. Catal. 2006, 240, 87.
[8] a) H. Huang, H. Liu, H. Jiang, K. Chen, J. Org. Chem. 2008, 73, 6037; b)
Y. Liang, Y. X. Xie, J. H. Li, J. Org. Chem. 2006, 71, 379.
[9] a) M. Pagliaro, V. Pandarus, R. Ciriminna, F. Beland, P. D. Cara,
ChemCatChem 2012, 4, 432; b) M. Schilz, H. Plenio, J. Org.
[22] S. Qu, H. Yang, D. Ren, S. Kan, G. Zou, D. Li, M. Li, J. Colloid Interface Sci.
1999, 215, 190.
Supporting Information
Additional supporting information may be found in the online ver-
sion of this article at the publisher’s web site.
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc