Pd-functionalized MCM-41 nanoporous silica as an efficient and reusable catalyst for promoting organic reactions

Article abstract of DOI:10.1039/c4ra11850b

Pd-functionalized MCM-41 nanoporous silica has been explored as an efficient and recyclable catalyst to effect Suzuki and Mizoroki-Heck cross-coupling reactions, under various conditions. In Suzuki-Miyaura reactions, various aryl halides were coupled with aryl boronic acids at 100 °C under solvent-free conditions using K₂CO₃ as base and the maximum Ar-Ar yield reached 95%. The MCM(Pd)-41 catalyst was also used for a good range of Heck reactions using different aryl halides with styrene or n-butyl acrylate esters at 130 °C under solvent-free conditions using n-Pr₃N as base that gave the maximum yields of 95% and 92%, respectively. High yield, low reaction times, non-toxicity and recyclability of the catalyst are the main merits of this protocol. The catalyst has been characterized by FT-IR, XRD, SEM, TEM, XPS, EDX, ICP-AES, TG and N₂ adsorption-desorption.

Full text of DOI:10.1039/c4ra11850b

RSC Advances
View Article Online
View Journal | View Issue
PAPER
Pd-functionalized MCM-41 nanoporous silica as an
efficient and reusable catalyst for promoting
organic reactions†
Cite this: RSC Adv., 2015, 5, 16029
a
a
Razieh Nejat, Ali Reza Mahjoub, Zahra Hekmatianb and Tahereh Azadbakhtb
*
Pd-functionalized MCM-41 nanoporous silica has been explored as an efficient and recyclable catalyst to
effect Suzuki and Mizoroki–Heck cross-coupling reactions, under various conditions. In Suzuki–Miyaura
reactions, various aryl halides were coupled with aryl boronic acids at 100 ꢀC under solvent-free
conditions using K2CO3 as base and the maximum Ar–Ar yield reached 95%. The MCM(Pd)-41 catalyst
was also used for a good range of Heck reactions using different aryl halides with styrene or n-butyl
acrylate esters at 130 ꢀC under solvent-free conditions using n-Pr3N as base that gave the maximum
yields of 95% and 92%, respectively. High yield, low reaction times, non-toxicity and recyclability of the
catalyst are the main merits of this protocol. The catalyst has been characterized by FT-IR, XRD, SEM,
TEM, XPS, EDX, ICP-AES, TG and N2 adsorption–desorption.
Received 6th October 2014
Accepted 22nd January 2015
DOI: 10.1039/c4ra11850b
www.rsc.org/advances
candidate as a support for homogeneous catalysts.17–19 At rst,
mesoporous silica synthesized by Mobil's researchers in 1992.
Introduction
The mesoporous molecular sieves such as MCM-41 with high
surface areas, tunable pore size, controlled morphology,
thermal stability and rich silanol groups in the inner walls has
proven to be suitable to be used as a catalyst support and
adsorbent.20–24 The chemical surface modication of MCM-41 is
essential because the mesoporous silica surface covered with
silanol groups is not selective enough to incorporation of active
metals such as Pd and its metallic complexes. Their surface
modication with addition of organic groups by graing orga-
nosiloxane precursors and ligands which lead to formation of
electron-rich metal complexes can enhance their stability and
selectivity.
In this work, we report the production of Pd catalyst based
on Schiff-base functionalized mesoporous molecular sieve
MCM-41, as an efficient and recyclable catalyst for C–C coupling
reactions including the Heck and Suzuki coupling reactions.
The reactions were performed under Solvent free condition with
high efficiency and excellent yields.
Palladium-based catalysts as versatile catalysts in modern
organic synthesis are widely employed in a signicant number
of synthetic transformations such as, hydrogenations, Heck,
Suzuki, Stille and Sono-gashira cross coupling reactions.1–7 The
resulting products have found widespread applications in the
synthesis of natural products, agrochemicals, pharmaceuticals,
and advanced materials.8–10
In designing new catalysts, two important parameters,
activity and recovery, in catalysis science have to be considered.
Some of the catalysts such as, homogeneous catalysts are very
active but their separation is not easy and they cannot be reused
in subsequent reactions. So, some demands cannot be satised.
Heterogeneous catalysts are superior to conventional
homogeneous catalysts because of easy recovering from the
reaction mixture by simple ltration and reused aer activation
and they cause economical viability in the processes
involved,11–14 but have low activity. Their low activity is attrib-
uted to the low active sites availability that limits the use of such
catalysts when in need of a perfect catalyst.15
A strategy for overcoming this problem could be xing a
homogeneous catalytic system into a heterogeneous system in
which the active centers are supported on large surface area
supports in order to achieve a high dispersion of the catalytic
active sites.16 Hence, mesoporous silica seems a promising
Results and discussion
The preparation and characterization of Pd immobilized onto
Schiff-base modied mesoporous silica surfaces (MCM(PA)-41)
are studied, and their catalytic performances are investigated.
These steps are illustrated in Fig. 1.
Fig. 2 shows the FTIR spectra of MCM(NH2)-41 and
MCM(Pd)-41. C–H and N–H vibration bands appeared in the
region 3000–3418 cmꢁ1 and 1450–1650 cmꢁ1 in the IR spectrum
of amine modied moiety, MCM(NH2)-41. The reaction between
amine group of 3-amino-propyltriethoxysilane (ATES) and
aChemistry Department, TarbiatModares University, P.O. Box 14155-4838, Tehran,
Iran. E-mail: mahjouba@modares.ac.ir; Fax: +98-21-82883455; Tel: +98-21-82883442
bFaculty of Chemistry, Bu-Ali Sina University, Hamedan 6517838683, Iran
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c4ra11850b
This journal is © The Royal Society of Chemistry 2015
RSC Adv., 2015, 5, 16029–16035 | 16029

View Article Online
RSC Advances
Paper
Fig. 1 Preparation of MCM(Pd)-41: (a) toluene/reflux, (b) CH3OH/
reflux and (c) CH3OH/reflux/Ar.
Fig. 4 The HR-TEM images of MCM(Pd)-41.
are observed for the Schiff-base-modied mesoporous, indi-
cating some structural disorder (Fig. 3b). This may indicate a
reduction in arrangement of ordered two dimensional hexag-
onal mesoporous channels of silica as a result of functionali-
zation. Also, the peak indicative of (100) diffraction shied to
the higher 2q, indicating a decrease in basal spacing (d100
)
owing to the increase of wall thickness of the pore channels.
The MCM(Pd)-41 exhibited an even weaker and broader peak
indicative of (100) diffraction, which demonstrated that the
deposition of metallic Pd particles on the Schiff-base-modied
mesoporous could further decrease the ordering degree of the
mesoporous structure. The damage of the ordered mesoporous
structure could be mainly attributed to the blockage of the pore
channels by these Pd particles. This was conrmed by the TEM
morphologies. As shown in the HR-TEM image in Fig. 4, the
MCM(Pd)-41 still preserved the ordered hexagonal mesoporous
structure. However, Pd particles deposited on the MCM(PA)-41
support in two ways. Most Pd particles of the Pd particles
anchored on the outer surface of the support and a fraction of
the Pd particles were distributed in the pore channels, which
could account for the positive shi of the peak position
observed in Fig. 3c, owing to the increase of the pore wall
thickness. Also this was conrmed by (BET) and (BJH) analysis
in Fig. 8a and b. However, it must be emphasized that HR-TEM
in any case cannot provide unambiguous molecular level
characterization of the active sites for two reasons. First, HR-
Fig. 2 FTIR spectra of (a) MCM(NH2)-41 and (b) MCM(Pd)-41.
carbonyl group of 2,20-(propane-1,3-diylbis(oxy))dibenzaldehyde
(PA) formed a C]N bond. Formation of this bond was identi-
ed with FT-IR spectra with an absorption band at 1646 cmꢁ1
.
Low-angle powder X-ray diffraction (XRD) patterns of pure
MCM-41, MCM(PA)-41 and MCM(Pd)-41 are illustrated in Fig. 3.
The patterns of MCM-41 showed four characteristic peaks that
can be indexed on a hexagonal lattice of a typical mesoporous
MCM-41 material as (100), (110), (200) and (210) planes.25
However, decreased intensity and some broadened reections
Fig. 3 XRD pattern of (a) MCM-41, (b) MCM(PA)-41 and (c) MCM(Pd)-
41.
Fig. 5 XPS spectra of MCM(Pd)-41.
16030 | RSC Adv., 2015, 5, 16029–16035
This journal is © The Royal Society of Chemistry 2015

View Article Online
Paper
RSC Advances
Fig. 6 The SEM micrographs of (a) MCM-41 and (b) MCM(Pd)-41.
TEM is known to modify small metal clusters on supports
during the imaging process.26 Secondly, the size of a tethered
mononuclear complex is expected to be beyond the reliable
resolution limit of HR-TEM.
X-ray photoelectron spectroscopy (XPS) helped determine
the oxidation state of the Pd surface in the catalyst (Fig. 5). The
binding energy curve showed a double peak at 335.35 (3d5/2
and 340.55 eV (3d3/2) that related to Pd (0).
)
Fig. 8 (a) N2 adsorption–desorption isotherms of MCM-41, MCM(PA)-
41, MCM(Pd)-41. (b) The BJH pore size distribution calculated from the
desorption branch of the isotherms of MCM-41, MCM(PA)-41,
MCM(Pd)-41.
The SEM micrographs of MCM-41 and MCM(Pd)-41 are
shown in Fig. 6a and b, respectively. SEM micrographs show
both materials have similar texture and there is no signicant
difference and also indicated that Pd is well dispersed in
MCM(C]N)-41 and can be used as a heterogeneous catalyst.
Thermogravimetric analysis of the MCM(Pd)-41 catalyst was
performed using the powder sample under nitrogen atmo-
sphere. TG curve as shown in Fig. 7 indicates that upon heating,
MCM(Pd)-41 showed a weight loss of about 3.47 wt% between
room temperature to 160 ꢀC, which are related to removal of
adsorbed water and solvent molecules. Upon further heating,
the TG curve shows a mass loss, about 21%, in the temperature
range from 180 to 640 ꢀC, which may be due to decomposition
of the organically modied framework. The loss centered at
higher temperature should be attributed to desorption of
several organic species. A third slight mass loss in TG curve of
about 0.94%, is also found in the temperature range from 680 to
As shown in this Table, the Schiff-base-modication caused the
decrease in the SBET, VP and dP, possibly due to the coverage of
the pore wall of the MCM-41 by the Schiff-base-groups, which
caused an increase in the wall thickness. The Pd-modication
further decreased the SBET, VP and dP, which could be easily
understood by considering the coverage of the Pd particles on
the outer surface, which may result in the blockage of the pore
channels, and the occupation of Pd particles in the pore chan-
nels, which may increase the pore wall thickness.
Inductively coupled plasma optical emission spectroscopy
(ICP/OES) analysis of the catalyst showed that the Pd content
was about 4.3 wt% Pd in the systems.
ꢀ
800 C, which corresponds to the water loss caused the weight
Suzuki cross-coupling reaction by MCM-(Pd)-41
loss also, as a result of the condensation of the silanol groups.
Nitrogen adsorption and desorption isotherms and BJH pore
size distribution of MCM-41, MCM(PA)-41 and MCM(Pd)-41
catalyst are presented in Fig. 8a and b. The results obtained
for analysis of textural characteristics (BET surface area, average
pore size and pore volume) of the samples are given in Table 1.
In order to investigate the catalytic performance of MCM(Pd)-41
and the effect of media upon the reaction, we preliminary
examined the model coupling reaction of bromobenzene with
phenylboronic acid as test compounds. The effects of solvents,
bases, reaction temperature and conditions on the yield were
studied using non-solvent condition and various solvents such
as DMSO, DMF, toluene and EtOH (Table 2). Comparison of the
results clearly shows that the reaction in solvent-free conditions
proceeded much better than in solvents with an excellent yield
Table 1 Textural properties of MCM-41 and MCM-41@Pd samples
BET surface
area (m2 gꢁ1
Pore volume
Pore diameter
(nm)
No.
Sample
)
(cm3 gꢁ1
)
1
2
3
MCM-41
MCM(PA)-41
MCM(Pd)-41
953.29
370
227.32
0.84
0.29
0.23
2.7
1.5
1.3
Fig. 7 Thermogravimetric analysis of the MCM(Pd)-41.
This journal is © The Royal Society of Chemistry 2015
RSC Adv., 2015, 5, 16029–16035 | 16031

View Article Online
RSC Advances
Paper
Table 2 Optimization studies for reaction of bromobenzene and Table 3 Suzuki reaction of aryl boronic acids with aryl halidesa
phenylboronic acid in the Suzuki reactiona
Try
Ar1X
Boronic acid
Time (h)
Yieldb (%)
Entry Base
Catalyst (g) Solvent T (ꢀC) Time
Yieldb (%)
1
2
PhB(OH)2
PhB(OH)2
20 min
30 min
92
90
1
—
0.01
0.01
0.005
0.01
0.01
0.01
0.01
0.01
0.01
0.01
None
None
None
None
DMF
100
80
100
100
130
130
12 h
1 h
1 h
45 min 90
6 h
6 h
—
85
82
2
3
4
6
7
8
9
10
11
12
13
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
KOAc
NaOH
3
PhB(OH)2
4 min
30 min
15 min
1 h
85
90
95
90
80
90
86
87
90
78
73
55
60
80
84
55
40
DMSO
Toluene Reux 6 h
4
PhB(OH)2
EtOH
None
None
None
None
Reux 6 h
5
4-NO2C6H4B(OH)2
2-NaphthylB(OH)2
2-NaphthylB(OH)2
PhB(OH)2
100
100
100
100
1 h
1 h
1 h
1 h
DABCO 0.01
n-Pr3N 0.01
6
a
7
1 h
Reaction conditions:
1 mmol of bromobenzene, 1.5 mmol of
phenylboronic acid, base (2 mmol), catalyst. b Isolated yield.
8
45 min
1 h
9
PhB(OH)2
and shorter reaction time. Also, various bases were examined
and it was found that the catalyst was very active and selective
for the reaction in the presence of K2CO3.
As seen in this table, it was noticed that, the reaction worked 11
out best at 100 ꢀC under solvent-free conditions using a (0.01 g)
10
PhB(OH)2
1 h
PhB(OH)2
1 h
catalyst using K2CO3 as base (90%, entry 4). This achievement
encouraged us to extend the scope of the reaction to a variety of
aryl halides and aryl boronic acids under the optimized condi-
tions in the Suzuki reaction (Table 3).
12
PhB(OH)2
PhB(OH)2
40 min
2 h
91
85
13
The ability to recover and reuse is another aspect that was
investigated for this catalyst. The reaction of phenylboronic acid 14
4-NO2C6H4B(OH)2
40 min
92
and bromobenzene as the model was chosen. Aer separating
a
the catalyst from the reaction, it was washed, dried and then
Reaction condition: MCM(Pd)-41 (0.01 g), aryl halide (1 mmol), aryl
boronic acid (1.5 mmol) and K2CO3 (2 mmol) under solvent free
conditions. b Isolated yield.
directly carried forward to the next reaction. As shown in Table
4, it was noticed that the recovered catalyst was recycling in
subsequent runs without observation signicant decrease in
activity even aer tenth run.
Experimental
Chemicals used in this work were purchased from Fluka, Lan-
caster, Aldrich and Merk chemical companies and used without
further purication. 1H NMR spectra were measured for
samples using a BRUKER DRX-300 AVANCE instrument at
300.13 and 75.47 MHz respectively, using Me4Si as internal
Mizoroki–Heck cross-coupling reaction catalyzed by MCM-
(Pd)-41
The MCM(Pd)-41 catalyst were also used for a good rang of Heck
reactions where the reaction of bromobenzene with styrene was
used as the model reaction. Various solvent, base, temperature
and catalyst loading were investigated in mentioned reactions.
The obtained optimized reaction conditions are presented in
Table 5.
Table 4 Recycling of the Pd-functionalized MCM-41 nanoporous
silica as the catalyst in Suzuki reaction of bromobenzene with phe-
nylboronic acid
ꢀ
As seen in Table 5, the reaction worked out best at 130 C
under solvent-free conditions using a (0.005 g) catalyst using n-
Pr3N as base (92%, entry 4). The reaction was then investigated
with different aryl halides with styrene and n-butyl acrylate
esters at the determined optimized conditions and the results
Cycle
1
2
3
4
5
6
7
8
9
10
78
Yield (%)
90
90
88
87
85
83
81
80
80
are summarized in Table 6.
16032 | RSC Adv., 2015, 5, 16029–16035
This journal is © The Royal Society of Chemistry 2015

View Article Online
Paper
RSC Advances
Table 5 Optimization studies for reaction of bromobenzene with Table 6 Heck reaction of aryl halides with n-butyl acrylate or styrenea
styrene in the Heck reactiona
Entry
ArX
Y
Time (h)
20 min
3 h
Yieldb (%)
Catalyst
(g)
Entry Base
Solvent
T (ꢀC) Time (h) Yieldb (%)
1
2
Ph
Ph
95
84
1
2
3
4
5
6
7
8
—
0.005
0.005
0.002
0.005
0.008
0.005
0.005
0.005
0.005
0.005
0.005
0.005
None
None
None
None
None
DMF
130
120
130
130
130
130
130
24 h
1 h
0.5
0.5
0.5
—
84
82
92
93
82
78
Trace
20
Trace
75
61
88
45
n-Pr3N
n-Pr3N
n-Pr3N
n-Pr3N
n-Pr3N
n-Pr3N
n-Pr3N
n-Pr3N
n-Pr3N
KOAc
3
4
5
Ph
Ph
Ph
30 min
4 h
92
80
91
5 h
5 h
DMSO
Toluene Reux 12 h
H2O
EtOH
None
None
None
None
9
Reux 12 h
Reux 12 h
130
130
130
130
10
11
12
13
14
4 h
3 h
3 h
3 h
3 h
NaOH
DABCO 0.005
Et3N 0.005
6
7
8
Ph
10 h
84
92
87
a
Reaction conditions: 1 mmol of bromobenzene, 1.5 mmol of styrene,
base (2 mmol) and catalyst. b Isolated yield.
–CO2Bu-n
–CO2Bu-n
30 min
4 h
standard. Melting points were measured on a SMPI apparatus.
The products were characterized by X-ray powder diffraction
(XRD) on Holland Philips X-pert diffractometer (Cu Ka ¼ 1.5418
9
–CO2Bu-n
–CO2Bu-n
–CO2Bu-n
4 h
1 h
4 h
90
88
82
˚
A). The FT-IR spectra were recorded on a Thermo Scientic
10
11
NICOLET IR100 FT-IR Spectrometer. The pellets made with KBr
and the catalysts were prepared before the analyses. Inductively
coupled plasma (ICP) data are provided by Varian vista-PRO.
The textural surface properties of the samples were deter-
mined by physical adsorption–desorption of N2 at ꢁ196 ꢀC
using a BELSORP-mini II (Bel Japan). Before the measurements,
the samples were degassed at 150 ꢀC for 1 h. The specic surface
area and the pore size distribution were calculated by the Bru-
nauer–Emmett–Teller (BET) and Brunauer–Joyner–Hallenda
(BJH) methods, respectively. The eld emission scanning elec-
tron microscopy (FESEM) analysis was carried out using a Phi-
lips XL-300. TEM images were taken using a Hitachi H 7600
12
–CO2Bu-n
1 h
87
13
14
–CO2Bu-n
–CO2Bu-n
1 h
88
91
1.5 h
TEM. The corresponding energy-dispersive X-ray (EDAX) spec- 15
trum was obtained on a Holland Philips XL30 microscope
instrument. Thermogravimetric analysis (TG) was performed
–CO2Bu-n
–CO2Bu-n
12 h
6
6
using PL-STA 1500 apparatus with the rate of 10 ꢀC minꢁ1 under
16
82
owing compressed N2. X-ray photoelectron spectroscopy (XPS)
a
was carried out by Dual anode (Mg and Al K alpha) achromatic
Reaction condition MCM(Pd)-41 (0.005 g), aryl halide (1 mmol), n-
butyl acrylate (1.5 mmol) or styrene (1.5 mmol) and n-Pr3N (2 mmol)
under solvent free conditions. Isolated yield.
X-ray source.
b
Preparation of MCM(Pd)-41 catalyst
Preparation of MCM-41 and inclusion of amine groups into
MCM-41. Mesoporous MCM-41 silica was prepared by the
method as described elsewhere.27 MCM-41 (1.0 g) and 3-amino-
propyltriethoxysilane (ATES) (1.0 mL) in dry toluene (20 mL)
were taken in a 50 mL round bottom ask and was stirred at
reux for 12 h under Ar atmosphere. The white solid was
removed from the solvent by ltration, washed with toluene and
chloroform, and dried at room temperature (MCM(NH2)-41).
(a) Preparation of 2,20-(propane-1,3-diylbis(oxy))-dibenzaldehyde
(PA). 1,3-Dibromo propane (0.1 mol) and NaOH (0.2 mol) were
mixed and heated under reux in 500 mL ethanol at 100 ꢀC.
This journal is © The Royal Society of Chemistry 2015
RSC Adv., 2015, 5, 16029–16035 | 16033

View Article Online
RSC Advances
Paper
Salicylaldehyde (0.2 mol) in 30 mL ethanol was added and heated the catalyst was very active and selective for the reactions in the
under reux for 4 days. Aer the cooling, the resulting yellow presence of K2CO3 and n-Pr3N, respectively. Moreover, the easy
crystals were ltered, washed and recrystallized.28
extractive recovery of the nal product, and the solid residue
(b) Preparation of MCM-supported 2,20-(propane-1,3-diylbis(oxy))- can be reused for several times, can be considered as strong
dibenzaldehyde (MCM(PA)-41). MCM(NH2)-41 (1.0 g) was suspended practical advantages of this method. This methodology could
in 15 mL of dry methanol and a solution of 0.1 g 2,20-(propane-1,3- provide a facile, efficient, and environmentally friendly process
diylbis(oxy))dibenzaldehyde in 5 mL dry methanol was added. Then for the Suzuki and Mizoroki–Heck cross-coupling reactions
was reuxed for 24 h under Ar atmosphere. The solid was ltered, because of its wide applicability to various substrates, the use of
washed (3 ꢂ 10 mL) with methanol and then dried under vacuum. less toxic reagents, and mild reaction conditions. High surface
(c) Preparation of palladium catalyst. MCM(PA)-41 (1.0) g was area and recyclability of the Pd-functionalized MCM-41 meso-
suspended in 15 mL of dry methanol and Pd(OAc)2 (0.1 g) in dry porous silica, solvent-free conditions, high yields products, low
methanol (5 mL) was added and the mixture was reuxed for 24 catalyst loadings, stability toward air and short reaction times in
h under Ar atmosphere. The solid was ltered, washed (3 ꢂ 10 many cases are comparable with other heterogeneous C–C
mL) with methanol and then dried under vacuum.
coupling reactions.
Application of catalyst for Suzuki reaction
Acknowledgements
A mixture of aryl halide (1.0 mmol), aryl boronic acid (1.5
mmol), K2CO3 (2.0 mmol), and MCM(Pd)-41 (0.01 g) are placed
in a mortar. The reaction mixture was then heated at 100 ꢀC for
an appropriate time (Table 3) until the completion of the reac-
tion was achieved as monitored by TLC. EtOAc (10 mL) was
added to the mixture, stirred for 5 min and ltered to separate
the catalyst. Then, water (3 ꢂ 15 mL) was added to the ethyl-
acetate phase and decanted. The organic layer was dried over
anhydrous Na2SO4. Aer evaporation of the solvent, the resulted
crude products were puried by column chromatography
(hexane/ethylacetate) giving the pure products in excellent
yields.
Financial support of this work by Tarbiat Modares University
and Iran National Science Foundation is gratefully
acknowledged.
Notes and references
´
´
1 Palladium-Catalyzed Coupling Reactions, ed. A. Molnar, Wiley-
VCH, Weinheim, 2013.
2 V. Polshettiwar, C. Len and A. Fihri, Coord. Chem. Rev., 2009,
253, 2599–2626.
´
´
´
3 A. Molnar, G. V. Smith and M. Bartok, J. Catal., 1986, 101, 67–
72.
Application of catalyst for Mizoroki–Heck reaction
¨ }
´
4 G. Szollosi, T. Hanaoka, S. Niwa, F. Mizukami and M. Bartok,
A mixture aryl halide (1.0 mmol), n-butyl acrylate (1.5 mmol) or
styrene (1.5 mmol), n-Pr3N (2.0 mmol) and MCM(Pd)-41 (0.005
g) are placed in a mortar. The reaction mixture was then heated
at 130 ꢀC for an appropriate time (Table 6) until the completion
of the reaction was achieved as monitored by TLC. EtOAc (10
mL) was added to the mixture, stirred for 5 min and ltered to
separate the catalyst. Then, water (3 ꢂ 15 mL) was added to the
ethylacetate phase and decanted. The organic layer was dried
over anhydrous Na2SO4. Aer evaporation of the solvent, the
resulted crude products were puried by column chromatog-
raphy (hexane/ethylacetate) giving the pure products in excel-
lent yields.
J. Catal., 2005, 231, 480–483.
¨ }
5 G. Szollosi, B. Herman, K. Felfoldi, F. Fulop and M. Bartok,
Adv. Synth. Catal., 2008, 350, 2804–2814.
6 F. Alonso, I. P. Beletskaya and M. Yus, Tetrahedron, 2005, 61,
11771–11835.
7 F. Alonso, I. P. Beletskaya and M. Yus, Tetrahedron, 2008, 64,
3047–3101.
8 N. Miyaura and A. Suzuki, Chem. Rev., 1995, 95, 2457–2483.
9 B. M. Choudary, S. Madhi, N. S. Chowdari, M. L. Kantam and
B. Sreedhar, J. Am. Chem. Soc., 2002, 124, 14127–14136.
10 A. Suzuki, J. Organomet. Chem., 1999, 576, 147–168.
11 S. Ikegami and H. Hamamoto, Chem. Rev., 2009, 109, 583–
593.
12 J. Lu and P. H. Toy, Chem. Rev., 2009, 109, 815–838.
13 G. M. Scheuermann, L. Rumi, P. Steure, W. Bannwarth and
R. Mulhaupt, J. Am. Chem. Soc., 2009, 131, 8262–8270.
Conclusion
In conclusion, we have developed a novel approach for the
preparation of supported Pd organometallic catalyst by using 14 L. D. Pachon and G. Rothenberg, Appl. Organomet. Chem.,
the Schiff-base functionalized MCM-41 as the support. 2008, 22, 288–299.
MCM(Pd)-41 catalyst exhibited high activity and selectivity, as 15 W. Teunissen, A. A. Bol and J. W. Geus, Catal. Today, 1999,
well as strong durability in Suzuki and Mizoroki–Heck cross- 48, 329–336.
coupling reactions under solvent-free conditions, without 16 A. Derrien, G. Renard and D. Brunel, Stud. Surf. Sci. Catal.,
using any Ar or N2 ow. We have successfully applied 2,20-
1998, 117, 445–452.
(propane-1,3-diylbis(oxy))dibenzaldehyde as a cheap and easily 17 S. Ito, A. Hayashi, H. Komai, Y. Kubota and M. Asami,
prepared ligand for preparation of Schiff-base functionalized Tetrahedron Lett., 2010, 51, 4243–4245.
MCM-41. Also, various bases were examined in Suzuki and 18 A. Hasaninejad, M. Shekouhy, N. Golzar, A. Zare and
Mizoroki–Heck cross-coupling reactions, and it was found that
M. M. Doroodmand, Appl. Catal., A, 2011, 402, 11–22.
16034 | RSC Adv., 2015, 5, 16029–16035
This journal is © The Royal Society of Chemistry 2015

View Article Online
Paper
RSC Advances
19 D. Meloni, R. Monaci, Z. Zedde, M. G. Cutrufello, S. Fiorilli 24 H. R. Lot Zadeh Zhad, O. Sadeghi, M. M. Amini,
and I. Ferino, Appl. Catal., B, 2011, 102, 505–514.
20 A. Monnier, F. Schuth, Q. Huo, D. Kumar, D. Margolese,
N. Tavassoli, M. H. Banitaba and S. S. H. Davarani, Sep.
Sci. Technol., 2011, 46, 648–655.
R. S. Maxwell, G. D Stucky, M. Krishnamurthy, P. Petroff, 25 J. Beck, J. Vartuli, W. Roth, M. Leonowicz, C. Kresge,
A. Firouzi, M. Janicke and B. F. Chmelka, Science, 1993,
261, 1299–1303.
21 C. Cai, H. Wang and J. Han, Appl. Surf. Sci., 2011, 257, 9802–
9808.
K. Schmitt, C. Chu, D. Olson, E. Sheppard, S. McCullen,
J. Higgins and J. Schlenker, J. Am. Chem. Soc., 1992, 114,
10834–10843.
26 F. Yang, E. Trufan, R. D. Adams and D. W. Goodman, J. Phys.
Chem. C, 2008, 112, 14233–14235.
22 H. Ebrahimzadeh, N. Tavassoli, O. Sadeghi, M. M. Amini,
S. Vahidi, S. M. Aghigh and E. Moazzen, Food Anal. 27 H. Chen and Y. Wang, Ceram. Int., 2002, 28, 541–547.
Methods, 2012, 5, 1070–1078.
23 Q. Qin, J. Ma and K. Liu, J. Hazard. Mater., 2009, 162, 133–
28 I. M. Atkinson, K. A. Byriel, P. S. K. Chia, C. H. L. Kennard,
A. J. Leong, L. F. Lindoy, M. P. Lowe, S. Mahendran,
G. Smith and G. Eei, Aust. J. Chem., 1998, 51, 985–989.
139.
This journal is © The Royal Society of Chemistry 2015
RSC Adv., 2015, 5, 16029–16035 | 16035