Phosphine-functionalized magnetic nanoparticles (PFMN) as a magnetic recyclable phosphorus ligand: Preparation of its palladium(II) complex for Heck reaction of chloroarenes

Article abstract of DOI:10.1016/j.jorganchem.2013.05.013

In this study, magnetic nanoparticles (MNs) were functionalized using chlorodiphenylphosphine (ClPPh2) and phosphine-functionalized magnetic nanoparticles (PFMN) as a recyclable phosphorus ligand was obtained. Also, palladium(II) complex of PFMN ligand (Pd-PFMN) was prepared and its catalytic activity was evaluated in the Heck reaction of chloroarenes. The results revealed that, this new catalyst showed high catalytic activity in the Heck reaction of chloroarenes and this can be attributed to the high reactivity of Pd complex involving phosphorus ligands and dispersible ability of MNs in solution as a high surface area support.

Full text of DOI:10.1016/j.jorganchem.2013.05.013

Journal of Organometallic Chemistry 741-742 (2013) 7e14
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Phosphine-functionalized magnetic nanoparticles (PFMN) as
a magnetic recyclable phosphorus ligand: Preparation of its
palladium(II) complex for Heck reaction of chloroarenes
*
*
Ali Khalafi-Nezhad , Farhad Panahi
Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
In this study, magnetic nanoparticles (MNs) were functionalized using chlorodiphenylphosphine
(ClPPh2) and phosphine-functionalized magnetic nanoparticles (PFMN) as a recyclable phosphorus
ligand was obtained. Also, palladium(II) complex of PFMN ligand (Pd-PFMN) was prepared and its cat-
alytic activity was evaluated in the Heck reaction of chloroarenes. The results revealed that, this new
catalyst showed high catalytic activity in the Heck reaction of chloroarenes and this can be attributed to
the high reactivity of Pd complex involving phosphorus ligands and dispersible ability of MNs in solution
as a high surface area support.
Received 14 February 2013
Received in revised form
3 April 2013
Accepted 8 May 2013
Keywords:
Magnetic nanoparticles
Phosphorus ligands
Phosphine-functionalized magnetic
nanoparticles
Ó 2013 Elsevier B.V. All rights reserved.
Heck reaction
Chloroarenes
1. Introduction
organic reactions [10]. Fortunately, to make a recyclable catalyst,
immobilization of ligands and homogeneous catalysts on different
Transition metal-catalyzed protocols, especially palladium re-
actions, have become powerful tools in chemical synthesis of many
materials [1e3]. In the context of Pd reactions, particularly CeC
bond formations, preparation of high performance catalyst and the
use of green reaction conditions have been considered [4,5].
Reactivity, stability and recycling of a catalyst system, are the most
important factors to develop a new applicable Pd catalyst [6,7].
High performance Pd catalysts are considered, because they allow
the use of aryl chlorides, which are less expensive than aryl bro-
mides or iodides, providing both cost effective and more efficient
reaction route. From the viewpoint of the reactivity, Pd complexes
involving phosphorus ligands are one of the reactive classes of Pd
catalysts [8]. However, phosphorus ligands as a precious ligand
often suffer from some disadvantages, such as intrinsic toxicity,
foul-smelling, easily oxidable during reaction process, difficulty of
extraction and purification process and lack of recovery capability
[9]. Supporting these ligands on a recyclable support is one of
the most important approaches to improve their applicability in
types of support materials has been extensively employed [11].
However, what is notable herein is that, the activity and selectivity
of immobilized catalyst were decreased frequently, as result of the
reduction in reactant diffusion rate to the surface of catalyst [12].
The latter problem can be resolved to some extent if support is
selected in smallest possible size. Otherwise, the resulted reactivity
due to homogeneous catalyst will not be fully effective in the re-
action. It seems that, nanoparticles are a good support candidate
because size of these materials is in the range of nanometre scale
which allows the surface area to increase dramatically. Moreover
nanoparticles are dispersible in solution, forming emulsion which
further increases the diffusion rate [13]. In addition, reactants in
solution have easy access to the active sites on the surface of
nanoparticles. On the other hand, when the size of support is
decreased in nanometre scale its recycleability using a simple
filtration is a huge problem. As a solution, the efforts have been
focused on magnetic recyclable supports such as magnetic nano-
particles (MNPs). Considered to the above mentioned points, when
MNs are used as the support, both reactivity and reusability
(catalyst can be separated from reaction condition using an
external magnetic field) could be improved. So, if the hypothesis of
phosphorus ligands on MNs directly (without any spacer) could be
realized in practice, it would be possible to prepare a magnetic
* Corresponding authors. Fax: þ98 711 2280926.
E-mailaddresses:khalafi@chem.susc.ac.ir(A. Khalafi-Nezhad),panahi@shirazu.ac.ir,
panahichem@ymail.com (F. Panahi).
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.05.013

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A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
recyclable phosphorus ligands. This new improved phosphorus
ligand can be used for preparation of transition metal complexes
such as Pd, Pt, Ru and Rh for the specific applications in the related
catalyzed reactions as catalyst.
However, to the best of our knowledge, up to now, there is no
general study on preparation of phosphine-functionalised MNs in
which magnetic reusable ligand has been described in this form. In
the current study, we would like to report a new and easy access
supported phosphine ligand on MNs (PFMN) for preparation of
an efficient heterogeneous Pd catalyst for Heck reaction of
chloroarenes.
plasma (ICP) analyzer (Varian, Vista-Pro). Transmission electron
microscopy (TEM) analyses were performed on a Philips model
CM 10 instrument. Melting points were determined in open
capillary tubes in a Barnstead Electro-thermal 9100 BZ circulating
oil melting point apparatus. The reaction monitoring was accom-
plished by TLC on silica gel PolyGram SILG/UV254 plates. Column
chromatography was carried out on columns of silica gel 60 (70e
230 mesh).
2.1. Preparation of Fe3O4 nanoparticles
In the current study, the Heck reaction was selected to evaluate
the catalyst activity, because it is one of the most notable and
widely used synthetic protocols for CeC bond formation [14]. In
general, use of only reactive substrates, low yield, prolonged reac-
tion time, tedious work-up processes, instability and lack of re-
covery capability of catalyst, are most important drawbacks linked
to the application of this method [15]. Although the methodology
for Heck reaction has been widely explored, but there is still
widespread interest to develop a new Pd catalyst system to over-
come these problems [16]. Herein, we report preparation, charac-
terization and catalytic application of a Pd(II) complex of PFMN
ligand (Pd-PFMN) in the Heck reaction of chloroarenes.
Magnetic nanoparticles were prepared via co-precipitation of
Fe(III) and Fe(II) ions in the presence of sodium hydroxide. In a
canonical flask, a mixture of FeCl2.2H2O (16 mmol, 2.6 g) and
FeCl3.6H2O (30 mmol, 8.1 g) was dissolved in 100 mL of deionized
water. Then, the pH of this solution was increased to 11 by adding a
3 M solution of NaOH as drop wise (in a period of 5 min) at 40 ꢀC.
Subsequently, the temperature of mixture was enhanced to 80 ꢀC
and the solution was stirred for 20 min in this temperature. The
magnetic nanoparticles as a dark solid were isolated from the so-
lution by magnetic separation and washed with deionized water
until pH 7 reached.
2.2. Preparation of Fe3O4@SiO2 nanoparticles
2. Experimental
Fe3O4@SiO2 nanoparticles were prepared based on the literature
with some modification: to a mixture of 250 mL of cyclohexane,
50 mL of 1-hexanol, 80 mL of triton X-100, and 25 mL of water, 2 g
of Fe3O4 was added. Then the mixture was stirred by mechanical
stirrer under N2 gas for 30 min. 20 mL of tetraethyl orthosilicate
(TEOS) was added to the mixture next and then the solution was
stirred for 12 h at 28 ꢀC. After the specified time, 18 mL of ammonia
was added and the solution was stirred continuously for another
12 h. The precipitation was washed with ethanol (3 ꢁ 10) and
collected by external magnetic field. The desired product was dried
under vacuum overnight.
Chemicals were purchased from Fluka and Aldrich chemical
companies and used without further purification. The known
products were characterized by comparison of their spectral and
physical data with those reported in the literature. 1H (500 MHz)
and 13C NMR (125 MHz) spectra were recorded on a Bruker Avance
spectrometer in CDCl3 solution with tetramethylsilane (TMS) as an
internal standard. X-ray diffraction (XRD, D8, Advance, Bruker, axs)
and FT-IR spectroscopy (Shimadzu FT-IR 8300 spectrophotometer)
were employed for characterization of the Pd-PFMN catalyst and
products. ICP analysis was determined using inductively coupled
Scheme 1. Synthetic route for the preparation of PFMN ligand and Pd-PFMN catalyst. i) TEOS, N2, ii) ClPPh2, Et3N, CH2Cl2, N2, iii) Pd (OAc)2, CH2Cl2, N2.

A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
9
2.3. Synthesis of phosphine-functionalized magnetic nanoparticles
(Fe3O4@SiO2@PPh2, PFMN)
To a mechanically stirred vessel mixture of Fe3O4@SiO2 (5.0 g) in
dry CH2Cl2 (80 mL), ClPPh2 (4.2 mmol, 0.76 mL) and triethyl amine
(1.0 mL) were added and refluxed under nitrogen gas for 12 h. Then,
the mixture was filtered and washed with dichloromethane
(3 ꢁ 10 mL) and deionized water (3 ꢁ 10 mL). After drying in the
oven at 100 ꢀC for 2 h, PFMN ligand was obtained as dark powder.
2.4. Preparation of Pd-PFMN catalyst
To a mixture of phosphine-functionalized magnetic nano-
particles (5 g) in dry CH2Cl2 (50 mL), palladium acetate (0.112 g,
0.5 mmol) was added and stirred for 24 h at room temperature
under nitrogen gas. Then, the mixture was filtered and washed
with dichloromethane (3 ꢁ 15 mL) and diethyl ether (2 ꢁ 15). After
drying in a vacuum oven at 100 ꢀC for overnight the Pd-PFMN
catalyst was obtained as a dark solid.
Fig. 2. a) The XRD pattern of Pd-PFMN catalyst. b) The EDX spectrum of Pd-PFMN
catalyst.
2.5. General procedure for the “Heck reaction” in the presence of
Pd-PFMN catalyst
The aqueous phase was extracted with diethyl ether (2 ꢁ 10 mL)
and the combined organic phases were dried over Na2SO4. The
products were purified by column chromatography (hexane/ethyl
acetate) to obtain the desired purity.
In a typical experiment, to a mixture of aryl halide (1 mmol),
acrylate/styrene (1.2 mmol), and K2CO3 (2 mmol) in 5 mL DMF, Pd-
PFMN catalyst (0.05 g, 1 mol %) was added and heated in an oil bath
at 120 ꢀC, for the time specified in Table 2 (main text). The reaction
was followed by TLC. After completion of the reaction, the mixture
was cooled down to room temperature and the catalyst was
magnetically separated from the reaction mixture and washed with
diethyl ether (2 ꢁ 10 mL) followed by deionized and oxygen-free
water (2 ꢁ 10 mL). The reused catalyst was dried for the next run.
2.6. Preparation of Pd-MN catalyst
To a mixture of Fe3O4@SiO2 (0.25 g) in dry CH2Cl2 (5 mL),
palladium acetate (0.006, 0.025 mmol) was added and stirred for
Fig. 1. The TEM image of a) synthesized MNs, b) & c) two different positions of Pd-PFMN catalyst surface. d) The histogram of Pd-PFMN catalyst.

10
A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
Fig. 3. A comparison between the FT-IR spectrum of the Pd-PFMN catalyst and Fe3O4@SiO2.
24 h at room temperature under nitrogen gas. Then, the mixture
was filtered and washed with dichloromethane (2 ꢁ 5 mL) and
diethyl ether (2 ꢁ 5 mL). After drying in a vacuum oven at 100 ꢀC for
overnight a dark solid was obtained.
preparation of PFMN ligand, because when non coreeshell MNs
were used, PFMN ligand is not produced in ideal form. It seems that
the silica shell not only prevents from the interactions and aggre-
gation of MNs during the catalyst preparation process it also makes
an easy access to connection of ePPh2 species to the surface of MNs.
After preparation of MNs, phosphine ligand is deposited on the
MNs using an O-linker by a chemical process. Thus, ClPPh2 was
used as the reagent for this purpose. Subsequently, the synthesized
MNs were reacted with ClPPh2 and the obtained data were shown
that under the mentioned condition (Scheme 1), the hydroxyl
groups of MNs react with ClPPh2 to produce the PFMN as a
phosphine-modified ligand. It is noteworthy that, by use of this
procedure the reaction of ClPPh2 with the iron oxide particles was
not resulted the immobilized phosphinate ligand (ePOPh2). Also,
ClPPh2 was not hydrolyzed during this process to form Ph2POH and
Ph2POPPh2 as byproducts. Finally, palladium acetate was com-
plexed with this supported ligand to produce the Pd-PFMN catalyst.
The Pd-PFMN catalyst was characterized using some different
techniques such as, transmission electron microscopy (TEM),
powder X-ray diffraction (XRD), energy dispersive X-ray spectra
(EDX) and FT-IR spectroscopy.
3. Results and discussion
3.1. Catalyst preparation and characterization
The preparation strategy for the Pd-PFMN catalyst is shown in
Scheme 1.
In this study, MNs were prepared by co-deposition method us-
ing a procedure in the literature [17]. This method is one of the
reliable and simple methods for the large-scale synthesis of MNs.
The synthesized MNs, were coated by silica using a solegel process
to obtain coreeshell MNPs (Fe3O4@SiO2) [18]. Based on this process
by hydrolysis and then condensation of TEOS the silica layer is
generated on MNs. The Fe3O4@SiO2 nanoparticles are necessary for
TEM image of the Pd-PFMN catalyst (Fig. 1aec) shows
that, the functionalized magnetic nanoparticles possess almost
spherical morphology with relatively good monodispersity. Com-
parison between MNs and Pd-PFMN catalyst is shown that the
Fig. 4. The comparison between TGA curves of Fe3O4 nanoparticles, Pd(OAc)2 and Pd-
PFMN catalyst.
Fig. 5. The XPS analysis of Pd-PFMN catalyst.

A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
11
Table 1
Study of various conditions for “Heck reaction” between chlorobenzene and ethyl acrylate using Pd-PFMN catalyst.a
O
Cl
OEt
Pd-PFMN
Base, Temperature
Solvent
+
OEt
O
1a
2a
3a
Entry
1
Solvent
DMF
Base
Temp (ꢀC)
Time (h)
Yield (%)b
K2CO3
120
5
12
5
12
12
5
5
5
5
12
93
94
78
53
57
72
94
79
95c
58d
2
3
4
5
6
7
8
9
DMSO
CH3CN
THF
DMF
DMF
DMF
DMF
DMF
K2CO3
K2CO3
K2CO3
Et3N
Cs2CO3
NaOH
K2CO3
K2CO3
120
Reflux
Reflux
120
120
120
120
120
a
Reaction condition: chlorobenzene (1 mmol), ethyl acrylate (1.2 mmol), catalyst (0.05 g, 1 mol%), base (1.5 mmol), solvent (5 mL).
Isolated yield.
0.075 g (1.5 mol%) of catalyst was used.
0.025 g (0.5 mol%) of catalyst was used.
b
c
d
monodispersity of catalyst is not changed significantly during
The XRD pattern of the Pd-PFMN catalyst also shows that we
have Fe3O4 nanoparticles as substrate for catalyst (Fig. 2). The peaks
are indexed as the (220), (311), (400), (422), (511) and (440) planes
of the Fe3O4 nanoparticle [19].
Also, to confirm the Pd content of catalyst, it was treated with
concentrated HCl and HNO3 to digest the Pd species and then
preparation process. In this study, the average diameter of the Pd-
PFMN catalyst was w10 nm. The histogram revealed the size dis-
tributions of catalyst nanoparticles (Fig. 1d). The histogram was
proposed according to the results obtained from the TEM image
and revealed the size distributions of catalyst nanoparticles.
Scheme 2. Products of Heck reaction between alkenes and aryl halides in the presence of Pd-PFMN catalyst. Reagents and conditions: alkene (1.2 mmol), aryl halide (1 mmol),
K2CO3 (2 mmol), catalyst (0.05 g, 1 mol%), DMF (5 mL), and 120 ꢀC. All yields are isolated yields.

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A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
Table 2
Comparison of the results of the synthesis of 1,2-diphenylethene, using Pd-PFMN-catalyzed Heck reaction of halobenzenes (Ph-X, X ¼ Cl, Br, I) and styrene (PhCH]CH2).
Entry [Ref.]
Catalyst
Reaction conditions
X
Time (h)
Yield (%)a
TOFb (hꢂ1
)
1 [This work]
Pd-PFMN
K2CO3, DMF, 120 ꢀC, 1.0 mol% Pd
I
Br
Cl
0.5
3
6
98
94
93
196
32
15
2 [5b]
PNP-PSS
K2CO3, H2O, reflux, 1.2 mol% Pd
Cl
Br
8
5
64
92
7
15
3 [26]
4 [27]
Pd-PANI
n-Pr3N, DMF, 130 ꢀC, 5 mol% Pd
TBAB, TBAA, 130 ꢀC, 0.35 mol% Pd
I
30
65
0.5
Pd-NPs-Chitosan
Cl
24
0
0
Br
15 min
98
1120
5 [28]
6 [29]
7 [30]
8 [31]
9 [32]
10 [33]
[Pd]-NaY
Pd-PVP
Pd(OAc)2
Palladaphosphacyclobutene
Palladacycle
NHC-Pd
NaOAc, DMAc, 140 ꢀC, 0.1 mol% Pd
Br
Br
Cl
Cl
Br
Br
20
45 min
24
24
3 min
15
85
36
99
15
90
90
42
4800
2
0.6
18,000
6
K2CO3, DMF, 120 ꢀC, 0.01 mol% Pd
Ligand: Dave-Phos (5 mol%), TBAE, Dioxane, 80 ꢀC, 2 mol%
NaOAc, DMA, 140 ꢀC, 1.0 mol% Pd
K2CO3, NMP, 130 ꢀC, 0.1 mol% Pd
Cs2CO3, Dioxane, 80 ꢀC, 1.0 mol% Pd
a
Isolated yield.
b
TOF ¼ (mol product/mol cat) hꢂ1
.
analyzed by ICP analysis. The Pd content was determined to be
22.1 ppm (22.1 mg/L) which was equal to 2.21% w/w.
In accordance with the FT-IR spectra, which are shown in Fig. 3,
the peaks positioned at w1575 and w467 cmꢂ1 are related to the
formation of Fe3O4 nanoparticles [20].
decomposition of phosphine species. So, the elevated temperature
for phosphine removal indicates the high thermal stability for
PFMN substrate, because phosphine is covalently bonded to the
MNs.
The chemical oxidation state of the Pd in Pd-PFMN catalyst was
also analyzed using XPS. The XPS spectrum of catalyst reveals that
there is only Pd(II) on the structure of Pd-PFMN catalyst (Fig. 5)
[25].
The FT-IR shows three bands at around 1648, 789 and 463 cmꢂ1
,
which are presumably due to asymmetric stretching (nas), sym-
metric stretching (ns), and bending modes of SieOeSi, respectively
[21]. These peaks demonstrated that SiO2 shell is properly gener-
ated around Fe3O4 nanoparticles cores. The peaks at w1650 and
1406 cmꢂ1 are to confirm the presence of acetate ligand in the
structure of Pd-PFMN catalyst [22]. Also, the peaks positioned at
1045 cmꢂ1 related to the formation of PeO bond [23]. Conse-
quently, PPh2 groups were connected to the magnetic support by an
O-linker. Any peak at around 1210e1140 cmꢂ1 which is related to
P]O bond is not observed [24]. This is confirmed that, the phos-
phine ligand during the preparation process is not oxidized.
The TGA curve of Pd-PFMN catalyst was shown two main weight
losses (Fig. 4).
3.2. Heck reaction of chloroarenes
The Pd-PFMN catalyst was applied in the Heck reaction to
evaluate the catalytic performance. To evaluate the catalytic reac-
tivity of the Pd-PFMN catalyst, the Heck reaction between chloro-
benzene (1a) and ethyl acrylate (2a) was selected as simple model
substrate and optimization condition is shown in Table 1.
According to the data which were obtained from optimizing
study (Table 1), the Heck reaction properly carried out at 120 ꢀC in
the presence of Pd-PFMN (1 mol%), using K2CO3 as base, without
addition of free ligand or any promoting additives in DMF solvent. It
is noteworthy that, Pd-PFMN catalyst is ferromagnetic and can
easily separated from the reaction mixture by simple magnetic
attraction (Fig. 6b & c).
The first one was occurred at w230 ꢀC which is related to
decomposition of palladium acetate from the Fe3O4@SiO2@PPh2
substrate. This part of the thermogram reveals the amounts of
palladium acetate on magnetic nanoparticle support which is
estimated to w7.8%, (W/W). Finally, the reduction in the weight
percentage of the catalyst at temperatures to w285 ꢀC is related to
After optimizing reaction conditions using chlorobenzene and
ethyl acrylate and in view of the fact that Pd-PFMN catalyst was an
Fig. 6. a) Reaction conditions: Pd-PFMN (0.05 g, 1 mol%), chlorobenzene (1.0 mmol), ethyl acrylate (1.2 mmol) and DMF (5 mL). Reaction time is 5 h. b) Reactants containing Pd-
PFMN catalyst. c) Recycled Pd-PFMN catalyst from reaction mixture.

A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
13
Table 3
Catalytic activity and recyclability of Pd-MN catalyst.
O
Cl
+
OEt
Pd-MN
K2CO3/ 1200C/DMF
OEt
O
1a
2a
3a
Entry
Catalyst (g)
Time (h)
Yield (%)
Fresh
Fresh
Fresh
Cycle 1
Cycle 2
0.05
0.075
0.1
0.98
0.97
12
12
12
12
12
55
64
68
48
31
efficient and reusable catalyst for Heck reaction of chloroarenes, the
catalyst was used to other substrates (Scheme 2).
4. Conclusion
As shown in Scheme 2, the Heck reaction of both electron-rich
and electron-deficient aryl chlorides also proceeded smoothly to
furnish the desired products with good to excellent yields. Evi-
dences show that, our environmentally benign catalyst system is
comparable with the classic homogeneous catalysts in efficiency.
In order to show the merit and the reactivity of Pd-PFMN catalyst
related to other catalysts, a comparison with some other reported
homogeneous and heterogeneous palladium catalysts for Heck
reaction of chloroarenes is presented in Table 2. As shown in
Table 2, our catalyst is superior to some of the previously re-
ported catalysts in terms of reaction condition, reaction time and
yield.
In conclusion, the phosphine-functionalized magnetic nano-
particles as a new supported ligand were synthesized and used for
complexation of palladium in order to prepare Pd-PFMN catalyst. In
PFMN ligand, P-atom is directly linked to the magnetic nanoparticle
via a surface O atom. We also reported preparation, characteriza-
tion and utilization of a new and high performance catalyst system
for Heck reaction of chloroarenes. This new catalyst can be well
dispersed in solution to produce a pseudo-homogeneous catalyst
system to generate a highly reactive catalyst sites. Reusability and
easy workup (using external magnetic attraction) were two other
advantages of this catalyst system. Also PFMN ligand and Pd-PFMN
catalyst provide great promise towards further useful applications
in other transition metal complexes and palladium transformations
in future, respectively.
3.3. The catalyst recyclability and heterogeneity tests
For practical applications of this heterogeneous catalyst, the
level of reusability was also evaluated. The recycled catalyst could
be reused for at least four times without any treatment (Fig. 6a).
The ICP analysis of the catalyst after five cycle of reusability was
shown that, only a very small amount (less than 1%) of the Pd metal
(in 0.1 g of catalyst) removed from the magnetic nanoparticle
substrate.
Acknowledgment
The financial supports of research councils of Shiraz University
are gratefully acknowledged.
Appendix A. Supplementary material
To confirm that the high activity of Pd-PFMN catalyst is resulted
from the supported palladium and not from the leached Pd, after
completion of the reaction between chlorobenzene and ethyl
acrylate under optimized condition, the catalyst was separated
from the reaction mixture and the obtained aqueous solution from
the hot filtration was applied for next operation. When the purifi-
cation processes were done, the obtained product was less than 3%.
The results confirmed that the supported palladium magnetic
nanoparticles provide the high catalytic activity without leach of
the significant quantity of Pd.
To establish the function of phosphine ligand in the stabilization
of Pd species on the surface of magnetic support, we examined the
following experiments. According to the procedure for synthesis of
Pd-PFMN catalyst we used from Fe3O4@SiO2 instead of Fe3O4@-
SiO2@PPh2 and as a result Pd on MNs (Pd-MNs) was obtained. The
catalytic usefulness of Pd-MNs was explored in the reaction be-
tween chlorobenzene and ethyl acrylate and results of this study
are summarized in Table 3.
Supplementary material associated with this article can
be found, in the online version, at http://dx.doi.org/10.1016/j.
jorganchem.2013.05.013.
References
[1] (a) A.M.R. Smith, K.K. Hii, Chem. Rev. 111 (2011) 1637e1656;
(b) L. Yin, J. Liebscher, Chem. Rev. 107 (2007) 133e173.
[2] (a) T.W. Lyons, M.S. Sanford, Chem. Rev. 110 (2010) 1147e1169;
(b) K. Niknam, A. Gharavi, M.R. Hormozi Nezhad, F. Panahi, M.T. Sharbatie,
Synthesis (2011) 1609e1615;
(c) A. Khalafi-Nezhad, F. Panahi, J. Organomet. Chem. 717 (2012) 141e146.
[3] (a) J. Magano, J.R. Dunetz, Chem. Rev. 111 (2011) 2177e2250;
(b) R. Jana, T.P. Pathak, M.S. Sigman, Chem. Rev. 111 (2011) 1417e1492.
[4] (a) F. Zhang, J. Jin, X. Zhong, S. Li, J. Niu, R. Li, J. Ma, Green Chem. 13 (2011)
1238e1243;
(b) J. Wang, B. Xu, H. Sun, G. Song, Tetrahedron Lett. 54 (2013) 238e241;
(c) B. Tamami, H. Allahyari, S. Ghasemi, F. Farjadian, J. Organomet. Chem. 696
(2011) 594e599.
[5] (a) D. Astruc, Inorg. Chem. 46 (2007) 1884e1894;
(b) A. Khalafi-Nezhad, F. Panahi, Green Chem. 13 (2011) 2408;
(c) G. Zhang, H. Zhou, J. Hu, M. Liu, Y. Kuang, Green Chem. 11 (2009)
1428e1432;
(d) M. Zeng, X. Zhang, L. Shao, C. Qi, X.M. Zhang, J. Organomet. Chem. 704
(2012) 29e37.
[6] (a) E.W. Werner, M.S. Sigman, J. Am. Chem. Soc. 132 (2010) 13981e13983;
(b) B. Yuan, Y. Pan, Y. Li, B. Yin, H. Jiang, Angew. Chem. Int. Ed. 49 (2010)
4047e4050;
As shown in Table 3, the catalytic activity and heterogeneity of
Pd-PFMN catalyst are not comparable with Pd-MNs in practice.
Obviously, Pd-PFMN is more active than Pd-MNs and its hetero-
geneity is superior. Accordingly, these experiments confirmed the
role of phosphine ligand in the stabilization of Pd species on the
MNs surface.

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A. Khalafi-Nezhad, F. Panahi / Journal of Organometallic Chemistry 741-742 (2013) 7e14
(c) S. Demir, I. Ozdemir, B. Cetinkaya, Appl. Organomet. Chem. 20 (2006)
254e259.
(d) N. Iranpoor, H. Firouzabadi, S. Motevalli, M. Talebi, J. Organomet.
Chem. 708e709 (2012) 118e124;
[7] (a) T.E. Barder, M.R. Biscoe, S.L. Buchwald, Organometallics 26 (2007)
2183e2192;
e) A. Houdayer, R. Schneider, D. Billaud, J. Ghanbaja, J. Lambert, Appl.
Organomet. Chem. 19 (2005) 1239e1248.
(b) Z. Bai, L. Yang, Y. Guo, Z. Zheng, C. Hu, P. Xu, Chem. Commun. 47
(2011) 1752e1754;
(c) P.Y. Wong, W.K. Chow, K.H. Chung, C.M. So, C.P. Lau, F.Y. Kwong,
Chem. Commun. 47 (2011) 8328e8330.
[17] D. Yuan, Q. Zhang, J. Dou, Catal. Commun. 11 (2010) 606e610.
[18] Y. Kang, L. Zhou, X. Li, J. Yuan, J. Mater. Chem. 21 (2011) 3704e3710.
[19] (a) C. Wang, H. Daimon, S. Sun, Nano Lett. 9 (2009) 1493e1496;
(b) K. Babu, R. Dhamodharan, Nanoscale Res. Lett. 3 (2008) 109e117.
[20] J. Sun, S. Zhou, P. Hou, Y. Yang, J. Weng, X. Li, M. Li, J. Biomed. Mater. Res. Part
A 80A (2007) 333e341.
[21] H. Sharghi, M.H. Beyzavi, M.M. Doroodmand, Eur. J. Org. Chem. (2008)
4126e4138.
[22] G. Eilers, C. Zettersten, L. Nyholm, L. Hammarström, R. Lomoth, Dalton Trans.
(2005) 1033e1041.
[8] (a) L.R. Falvello, J.C. Ginés, J.J. Carbó, A. Lledós, R. Navarro, T. Soler,
E.P. Urriolabeitia, Inorg. Chem. 45 (2006) 6803e6815;
(b) C.A. Tolman, Chem. Rev. 77 (1977) 315e353;
(c) X. Yan, Y. Liu, C. Xi, Appl. Organomet. Chem. 22 (2008) 341e345.
[9] (a) W. Tang, X. Zhang, Chem. Rev. 103 (2003) 3029e3069;
(b) M. Doux, N. Mézailles, M. Melaimi, L. Ricard, P.L. Floch, Chem. Commun.
(2002) 1566e1567;
(c) H. Butenschön, Chem. Rev. 100 (2000) 1527e1564.
[10] (a) T. Yamamoto, T. Yamada, Y. Nagata, M. Suginome, J. Am. Chem. Soc. 132
(2010) 7899e7901;
(b) X. Zhang, P. Li, Y. Ji, L. Zhang, L. Wang, Synthesis (2011) 2975e2983.
[11] D. Astruc, F. Lu, J.R. Aranzaes, Angew. Chem. Int. Ed. 44 (2005) 7852e7872.
[23] K.A. Lyssenko, G.V. Grintselev-Knyazev, M.Y. Antipin, Mendeleev Commun. 12
(2002) 128e130.
[24] H.I. Hsiang, C.C. Chen, J.Y. Tsai, Appl. Surf. Sci. 245 (2005) 252.
[25] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, in: Handbook of X-ray
Photoelectron Spectroscopy, Physical Electronics Inc., USA, 1995, p. 118.
[26] A. Houdayer1, R. Schneider, D. Billaud, J. Ghanbaja, J. Lambert, Appl.
Organomet. Chem. 19 (2005) 1239e1248.
[12] P.D. Stevens, J.D. Fan, H.M.R. Gardinmalla, M. Yen, Org. Lett.
2085e2088.
7 (2005)
[27] V. Calo, A. Nacci, A. Monopoli, A. Fornaro, L. Sabbatini, N. Cioffi, N. Ditaranto,
Organometallics 23 (2004) 5154e5158.
[13] (a) J. Fan, S. Chen, Y. Gao, Colloids Surf. B 28 (2003) 199e207;
(b) A. Khalafi-Nezhad, H.O. Foroughi, M.M. Doroodmand, F. Panahi, J. Mater.
Chem. 21 (2011) 12842e12851.
[28] L. Djakovitch, K. Koehler, J. Am. Chem. Soc. 123 (2001) 5990e5999.
[29] F. Durapa, O. Metin, M. Aydemir, S. Ozkar, Appl. Organomet. Chem. 23 (2009)
498e503.
[30] H.J. Xu, Y.Q. Zhao, X.F. Zhou, J. Org. Chem. 76 (2011) 8036e8041.
[31] X. Yan, Y. Liu, C. Xi, Appl. Organomet. Chem. 22 (2008) 341e345.
[32] A.R. Hajipour, K. Karami, A. Pirisedigh, Appl. Organomet. Chem. 23 (2009)
504e511.
[14] (a) B.P. Carrow, J.F. Hartwig, J. Am. Chem. Soc. 132 (2010) 79e81;
(b) A. Littke, G. Fu, Angew. Chem. Int. Ed. 41 (2002) 4176e4211.
[15] J.P. Corbet, G. Mignani, Chem. Rev. 106 (2006) 2651e2710.
[16] (a) P.D. Stevens, G. Li, J. Fan, M. Yen, Y. Gao, Chem. Commun. (2005)
4435e4437;
(b) B. Baruwati, D. Guin, S.V. Manorama, Org. Lett. 9 (2007) 5377e5380;
(c) S. Ko, J. Jang, Angew. Chem. Int. Ed. 45 (2006) 7564e7567;
[33] I. Ozdemir, M. Yigit, E. Cetinkaya, B. Cetinkaya, Appl. Organomet. Chem. 20
(2006) 187e192.