Pd-porphyrin functionalized ionic liquid-modified mesoporous SBA-15: An efficient and recyclable catalyst for solvent-free Heck reaction

Article abstract of DOI:10.1016/j.materresbull.2010.07.006

The Pd-porphyrin functionalized ionic liquid could be covalently anchored in the channels of mesoporous SBA-15 through ion-pair electrostatic interaction between imidazolium-cationic and Pd-porphyrin-anionic moieties. Such modified SBA-15 materials were prepared successfully via a post-synthesis (surface sol-gel polymerization) or a one-pot sol-gel procedure, which were characterized by powder X-ray diffraction, UV-visible spectroscopy, Fourier transform infrared spectroscopy, N₂ sorption, elemental analysis, and transmission electron microscopy. The modified SBA-15 materials are efficient and recyclable catalysts for cross-coupling of aryl iodides or activated aryl bromides with ethyl acrylate without activity loss and Pd leaching even after 9 runs.

Full text of DOI:10.1016/j.materresbull.2010.07.006

Materials Research Bulletin 45 (2010) 1648–1653
Contents lists available at ScienceDirect
Materials Research Bulletin
journal homepage: www.elsevier.com/locate/matresbu
Pd-porphyrin functionalized ionic liquid-modified mesoporous SBA-15:
An efficient and recyclable catalyst for solvent-free Heck reaction
a
a
b
a
a,
Jing Zhang , Guo-Feng Zhao , Zora Popovi c´ , Yong Lu , Ye Liu *
a
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062, China
b
General and Inorganic Laboratory, Chemistry Department, University of Zagreb, HR-10000 Zagreb, Croatia
A R T I C L E I N F O
A B S T R A C T
Article history:
The Pd-porphyrin functionalized ionic liquid could be covalently anchored in the channels of
mesoporous SBA-15 through ion-pair electrostatic interaction between imidazolium-cationic and Pd-
porphyrin-anionic moieties. Such modified SBA-15 materials were prepared successfully via a post-
synthesis (surface sol–gel polymerization) or a one-pot sol–gel procedure, which were characterized by
Received 2 February 2010
Received in revised form 29 June 2010
Accepted 16 July 2010
Available online 23 July 2010
2
powder X-ray diffraction, UV–visible spectroscopy, Fourier transform infrared spectroscopy, N sorption,
elemental analysis, and transmission electron microscopy. The modified SBA-15 materials are efficient
and recyclable catalysts for cross-coupling of aryl iodides or activated aryl bromides with ethyl acrylate
without activity loss and Pd leaching even after 9 runs.
Keywords:
A. Composites
A. Organic compounds
B. Chemical synthesis
D. Catalytic properties
ß 2010 Elsevier Ltd. All rights reserved.
1
. Introduction
The palladium catalyzed Heck reaction is one of the most
cy [21–26]. Another advantage of supported-IL phases over IL-liquid
phases is in minimizing the amounts of costly ILs which may affect
the economic viability of a potential process when environmentally
benign syntheses are being considered [27,28]. In numerous solid
supports applied in SILP catalysis, mesoporous silica, such as SBA-15
[29] and MCM-41 [30], with good thermal/oxidative stability, highly
ordered channel structures of pore diameter in the range of 1.5–
widely used catalytic carbon–carbon bond forming tools in organic
synthesis to achieve substituted alkenes, dienes, and other
unsaturated structures, many of which are important intermedi-
ates in the natural product synthesis and in the production of fine
chemicals [1]. For a great variety of Pd-catalysts applied in
homogenous processes, Heck reaction suffers from disadvantages
like large amount of volatile solvents required, toxic and air/
moisture phosphine ligands used, Pd-catalyst recovery and
recyclability unavailable [1,2]. Thus, the immobilization of
palladium catalyst on a solid support like polymer, inorganic
oxides, zeolites, etc. has attracted considerable attention [3–7].
However, organic synthesis using supported insoluble catalysts
leads to a series of problems including mass transfer limitation,
decreased activity, catalysts leaching out of the solid support, etc.
This has led to alternative ‘‘liquid phase’’ methodologies with the
aim to ‘‘restore’’ homogeneous reaction conditions, like using ionic
liquids (ILs) as mobile and versatile ‘‘carriers’’ [8–13], ‘‘soluble
polymer supports’’ [14,15], and ‘‘fluorous phase’’ [16,17].
2
30 nm, and huge internal surface areas of 700–1000 m /g [31], are
suitable supports to accommodate functionalized ILs (as catalysts)
and facilitate the diffusion of bulky reactant molecules.
In this work, the Pd-porphyrin functionalized IL was covalently
anchored in the channels of mesoporous SBA-15 via ion-pair
electrostatic interaction, aiming to develop a new heterogeneous
catalyst for the Heck reaction of aryl iodides (or aryl bromides) and
ethyl acrylate without defeating the activity of Pd-porphyrin
catalyst and forfeiting the nature of heterogeneous catalysis.
Scheme 1 shows the strategy for synthesizing the SBA-15
supported anionic (meso-tetra-(p-sulfonatophenyl)-porphyrina-
4
ꢀ
to)palladium ([PdTSPP] ) catalyst, which is confined in the
channels of imidazolium-based IL-modified SBA-15 (PMIM-SBA-
15) tightly and stoichiometrically through electrostatic interac-
tion. The imidazolium cations which are covalently and stoichio-
metrically bonded to SBA-15 act as the linkers between SBA-15 and
More recently, the supported-IL-phase (SILP) catalysis [18–20]
has been shown as an alternative approach for the development of
novel heterogeneous catalysts with advantages of facilitating
separation workup and ‘‘restoring’’ homogeneous catalytic efficien-
4
ꢀ
the catalytic sites of [PdTSPP] anions. Since only the stability and
loading of the cations are considered when they are covalently
bonded to SBA-15, without burden of functionality incorporation,
the selection of the cations becomes a more simple and flexible
4
ꢀ
task. Then the functional moieties ([PdTSPP] ) located in the
anions can be maintained intact during the immobilization.
*
Corresponding author. Fax: +86 21 62233424.
E-mail address: yliu@chem.ecnu.edu.cn (Y. Liu).
0025-5408/$ – see front matter ß 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.materresbull.2010.07.006

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J. Zhang et al. / Materials Research Bulletin 45 (2010) 1648–1653
1649
Scheme 1. Strategy for synthesizing SBA-15-supported Pd-porphyrin functionalized ILs: (a) post-synthesis, (b) one-pot sol–gel synthesis.
2
. Experimental
at room temperature for 8 h. The obtained brick-red solid was
washed with water, ethanol, CH CN, Et N, and PhI, respectively,
until the Soret band of [PdTSPP]Na at 414 nm could not be
3
3
2.1. Materials
4
observed in the final filtrate, which was detected by the UV–visible
(UV–vis.) spectroscopy.
Tetraethyl orthosilicate (TEOS), Pluronic P123 (poly(ethylene-
glycol)–poly(propylene glycol)–poly(ethylene glycol), average
molecular mass 5800), 3-chloropropyltrimethoxysilane, N-methy-
limidazole were of commercial grade and used as received. The
2.2.1.3. [PdTSPP]Na
comparison [PdTSPP]Na
wet impregnation method as follows. 300 mg SBA-15 was mixed
with 43 mg [PdTSPP]Na and 5 mL methanol. The mixture was
stirred at room temperature for 1 h. However, when the obtained
brick-red solid after filtration was washed with water and ethanol,
its color changed to pale-yellow and the red filtrate was obtained,
4
-modified SBA-15 ([PdTSPP]Na
4
-SBA-15). For
4
-modified SBA-15 was prepared through
other reagents including PdCl
AR), triethylamine (AR), and n-dodecane, etc. were purchased
from Alfa Aesar.
2
, ethyl acrylate (AR), iodobenzene
(
4
2.2. Synthesis
due to the loss of [PdTSPP]Na
brick-red solid after vacuum drying was directly used as the
sample of [PdTSPP]Na -SBA-15 without further treatment. The
inductive coupled plasma (ICP) analysis of Pd in [PdTSPP]Na -SBA-
5 was 1.01 wt%. UV–vis. (solid disc, nm): 405 (Sore band, s), and Q
4
out of SBA-15 surface. Hence, the
2
2
.2.1. Post-synthesis
4
.2.1.1. Chloropropyl-grafted SBA-15 (Post-CP-SBA-15). SBA-15 was
4
synthesized following the procedures reported by Zhao et al. [29].
.6 g SBA-15 (calcined at 550 8C for 4 h) and 4.5 g 3-
1
5
bands (524 (s), 557(w), and 610 (w) nm), which are very similar to
the characteristic absorbances of Post-PdTSPP-PMIM-SBA-15
chloropropyltrimethoxysilane were mixed in 150 mL toluene
and stirred vigorously for 1 h at room temperature. The obtained
mixture after adding 0.65 g deionized water and 0.34 g toluene-p-
sulfonic acid was stirred at 120 8C for 8 h. The obtained solid was
washed with toluene, ethanol, and diethyl ether before dryness in
oven at 90 8C, which was referred to as Post-CP-SBA-15.
(Fig. 3(a)).
2.2.2. One-pot-synthesis
2.2.2.1. Chloropropyl-grafted SBA-15 (One-pot-CP-SBA-15). Chloro-
propyl-grafted SBA-15 was synthesized following the procedures
reported by Bordoloi et al. [33]. 4 g Pluronic P123 was added into
30 mL deionized water under vigorous stirring for 3 h, and then
120 g of 2.0 M HCl solution was added. The resultant mixture was
stirred at 25 8C for 10 min, in which 8.50 g TEOS (40.7 mmol) and
0.81 g (4.07 mmol) 3-chloropropyltrimethoxysilane were subse-
quently introduced. The mixture was stirred vigorously at 35 8C for
24 h, and aged for another 24 h at 80 8C without stirring. The solid
product was obtained after filtration, and then washed in HCl
2.2.1.2. Pd-porphyrin functionalized IL-modified SBA-15 (Post-
PdTSPP-PMIM-SBA-15). 2.5 g Post-CP-SBA-15 and 0.3 g N-methy-
limidazole were mixed in 80 mL toluene. After refluxing for 15 h
under vigorous stirring, the obtained solid was washed by ethanol
and then dried in vacuo to give Post-PMIM-SBA-15.
To 600 mg Post-PMIM-SBA-15 was added 200 mg (meso-tetra-
(
p-sulfonatophenyl)-porphyrinato)palladium sodium ([PdTSPP]
Na ) [32] and 15 mL deionized water. The mixture was stirred
4

1
650
J. Zhang et al. / Materials Research Bulletin 45 (2010) 1648–1653
[
F
g
_
)
D
F
]
(
2.0 M)-ethanol solution under stirring for 3 h at 50 8C to remove
the organic templates. The as-synthesized product was dried at
00 8C for 2 h to yield chloropropyl-grafted SBA-15 (referred to as
1
One-pot-CP-SBA-15).
It was found that more ratio of 3-chloropropyltrimethoxysilane
in TEOS led to unsuccessful preparation of typical mesoporous
SBA-15.
2
.2.2.2. Pd-porphyrin functionalized IL-modified SBA-15 (One-pot-
PdTSPP-PMIM-SBA-15). Upon quaternizing One-pot-CP-SBA-15 by
N-methyl imidazole and then ion-exchanging with [PdTSPP]Na
4
,
One-pot-PdTSPP-PMIM-SBA-15 was obtained following the simi-
lar procedures as described in the part for synthesizing Post-
PdTSPP-PMIM-SBA-15.
2.3. Characterization
Fourier transform infrared (FT-IR) spectra were recorded on a
Nicolet NEXUS 670 spectrometer. Elemental analyses for CHN were
obtained by using an Elementar Vario EL III instrument; while Pd
amount in the sample was quantified using ICP analysis on an IRIS
Intrepid II XSP instrument (Thermo Electron Corporation). Powder
X-ray diffraction (PXRD) patterns were collected on a Bruker AXS D8
Fig. 1. PXRD patterns of (a) SBA-15, (b) Post-CP-SBA-15, and (c) Post-PdTSPP-PMIM-
SBA-15.
ADVANCE with Cu K
(
(
a
radiation. Transmission electron microscopy
TEM) measurement was carried out on a JEM-2100 instrument
JEOL Ltd., resolution 5 nm). The samples were loaded on gold slices
Pd-porphyrin functionalized IL of PdTSPP-PMIM-SBA-15, which
was thoroughly washed to remove the physically absorbed
after sono-irradiation in acetone for TEM characterization. The UV–
visible spectra were recorded on a SHIMADZU-UV 2550 spectro-
photometer with resolution of ca. 1 nm. GC analyses were
performed on a SHIMADZU-2014A chromatography equipped with
4
[PdTSPP]Na . The formation of highly water-soluble salt of NaCl
is the driving force for such ion-exchange reaction. Based on such
synthesis route, the covalently and stoichiometrically bonded 1-
propyl-3-methylimidazolium cation without burden of the com-
plicated catalytic site can guarantee the robustness of itself on SBA-
15; Pd-porphyrin catalytic moiety located in the anion then can be
maintained intactly, tightly, and stoichiometrically via the
subsequent electrostatic interaction.
Rtx-Wax capillary column (30 m ꢁ 0.25 mm ꢁ 0.25
mm). The col-
umn temperature was programmed from 60 to 240 8C at a ramp of
1
1
2
0 8C/min with a hold time of 3 min at the initial temperature and
0 min at the final temperature. The injector temperature was
50 8C. The detector temperature was 250 8C. GC–MS analyses were
Firstly, the post-synthesized samples (Post-CP-SBA-15, and
Post-PdTSPP-PMIM-SBA-15) were characterized by means of
recordedonan Agilent6890 instrument equipped withAgilent5973
mass selective detector. The same GC analysis conditions as
mentioned above were applied to GC–MS analyses.
different techniques, including PXRD, FT-IR, UV–visible, ICP, N
sorption analysis, and TEM.
2
The pore diameter, pore volume, and surface area of the
PXRD patterns in Fig. 1(b) show that Post-CP-SBA-15 exhibits
an intensive reflection at 2 = 1.018, which is characteristic of a
samples were obtained from N
2
sorption isotherm at 77 K using an
u
Autosorb Quancachrome 02108-KR-1 instrument.
two-dimensional hexagonal structure (p6mm) for typical SBA-15
silica (Fig. 1(a)). It is found that when grafting chloropropyl group
in SBA-15 framework (1 0 0) reflection intensity decreases slightly,
whereas (1 1 0) and (2 0 0) reflections are rarely observed (Fig. 1(c),
CP-SBA-15-II). Upon quaternization by N-methyl imidazole and
2.4. Catalytic activity test
Iodobenzene (2.5 mmol), ethyl acrylate (3.75 mmol), triethy-
lamine (Et
3
N, 3.75 mmol), and SBA-15-supported Pd-catalyst were
subsequent ion-exchange with [PdTSPP]Na
of Post-PdTSPP-PMIM-SBA-15 (Fig. 1(c)) exhibits the similar
reflection at 2 = 1.038 but with dramatic decrease of reflection
intensity, due to the decrease of long-range order after modifica-
tion. The slight shift of the characteristic reflection to higher degree
is observed in Post-PdTSPP-PMIM-SBA-15, which corresponds to
the decrease in d100 spacing from 8.65 to 8.49 nm as a cause of
incorporation of organic functional group in host SBA-15 (Table 1)
4
, the obtained sample
mixed and sealed in the glass vial under vigorous stirring at
appointed conditions on an Advantage Series TM 2410 Personal
Screening Synthesizer (Argonaut Technologies Inc.). Upon com-
pletion, the reaction mixture was cooled to room temperature to
yield a slurry solid which was extracted with diethyl ether (4ꢁ
u
2
mL). The ether fractions were combined, and then analyzed by GC
to determine the conversions (n-dodecane as internal standard)
and the selectivities (normalization method). The left solid
[31]. In the wide-angle region of PXRD (inset: 2
u = 30–608,
containing the catalyst and the formed salt of Et
used without further treatment for the next run.
3
NꢂHI was then
Fig. 1(c)), the absence of [PdTSPP]Na reflections suggests the
4
4ꢀ
high dispersion of [PdTSPP] ions in the channels of SBA-15.
The sample of Post-PdTSPP-PMIM-SBA-15 was further charac-
terized by FT-IR and UV–visible spectra. Upon functionalization, the
3
. Results and discussion
.1. Characterization of the catalysts
According to the strategy in Scheme 1, the imidazolium-based
ꢀ
1
typical IR vibration for silanol groups is observed at 3740 cm , due
to the exposure of hydroxyl derived from the partial collapse of host
SBA-15 framework. This result is consistent to the decreased
reflection intensity in XRD pattern for Post-PdTSPP-PMIM-SBA-15
due to the decrease of long-range order. The appearance of vibration
3
IL grafted mesoporous silica, PMIM-SBA-15, was prepared through
anchoring chloropropyl group to the framework of SBA-15 and
then quaternizing N-methylimidazole. The subsequent ion-ex-
ꢀ
1
ꢀ1
peaks of C–H bonds (2800–3200 cm ), C 55 C bonds (ꢃ1570 cm ),
C 55 N bonds (ꢃ1460 cmꢀ ) (Fig. 2) indicates the presence of 1-
propyl-3-methylimidazolium group and porphyrino ring structure.
1
4
change with [PdTSPP]Na in water afforded the SBA-15 supported

J. Zhang et al. / Materials Research Bulletin 45 (2010) 1648–1653
1651
Table 1
a
Physicochemical properties of the post-synthesized samples .
Sample
PXRD
100 (nm)
N
2
sorption isotherms
Elemental analysis
Pd (wt %)
2
3
d
SBET (m /g)
D
BJH (nm)
V
t
(cm /g)
N (wt %)
Post-CP-SBA-15
8.65
8.49
509
220
4.19
4.76
0.52
0.27
–
–
Post-PdTSPP-PMIM-SBA-15
1.37
2.98
a
S
BET, BET specific surface area; DBJH, pore diameter calculated using BJH method; V
t
, total pore volume; Pd amount was based on ICP-AES analysis; N amount was based on
CHN-elemental analysis.
The UV–visible spectra of Post-PdTSPP-PMIM-SBA-15 (soliddisc)
in Fig. 3(a) show the typical Sore (405 nm) and Q bands (524, 557,
and 607 nm), which are similar to the characteristic absorbances of
capture of Pd-porphyrin functionalized IL, the total surface area
2
(SBET) and pore volume (V
t
) decrease from 509 to 220 m /g and from
3
0.52 to 0.27 cm /g, respectively, along with a slight increase of the
average pore size (DBJH) from 4.19 to 4.76 nm due to the collapse of
the partial mesopores. These results indicate that the void pores of
Post-CP-SBA-15 havebeenoccupied byPd-porphyrinfunctionalized
ILs.
[
PdTSPP]Na
intensity of Q bands of Post-PdTSPP-PMIM-SBA-15 increases
dramatically, implying the more active m( *) transition
) ! e
34,35], probably due to the changed * interaction derived from
the isolated [PdTSPP] sites by SBA-15 skeleton.
adsorption–desorption isotherms for Post-CP-SBA-15 and
resultant Post-PdTSPP-PMIM-SBA-15 were given in Fig. 4. Table 1
summarizedthe resultsofN sorption analysis, PXRD,and elemental
analysis for Pd and N. The isotherms feature hysteresis loops with
clear adsorption and desorption branches in the P/P range of 0.4–
.7, indicating a narrow mesopore size distribution (Fig. 4(b)). After
4
dissolved in water (Fig. 3(b)). However, the absorbance
a
2
p
g
(p
[
p–p
4ꢀ
Molar ratio 16 of N/Pd (Table 1) in sample Post-PdTSPP-PMIM-
4ꢀ
N
2
SBA-15 also reveals that each [PdTSPP] anion is counteracted by
four imidazolium cations stoichiometrically with additional imida-
zolium chlorides distributed sparsely in the channel of host SBA-15.
The TEM images provide a direct visualization for the samples
of Post-CP-SBA-15 and Post-PdTSPP-PMIM-SBA-15. Fig. 5(a) clear-
ly shows uniform and long-range ordered hexagonal channels of
Post-CP-SBA-15 which are open for guest molecules to enter. Upon
2
0
0
[(Fig._2)TD$FIG]
4
ꢀ
quaternization by N-methylimidazole and capture of [PdTSPP]
[(Fig._4T)D$FI]G
Fig. 2. FT-IR spectra of (a) SBA-15, (b) Post-CP-SBA-15, and (c) Post-PdTSPP-PMIM-
SBA-15.
[(Fig._3)TD$FIG]
Fig. 4. (a) N
2
sorption isotherms of Post-CP-SBA-15 (
D
), and Post-PdTSPP-PMIM-
), and Post-PdTSPP-
SBA-15 (ꢄ); (b) Pore size distribution of Post-CP-SBA-15 (
D
Fig. 3. UV–visible spectra of (a) Post-PdTSPP-PMIM-SBA-15 (solid disc) and (b)
PdTSPP]Na (in water).
PMIM-SBA-15 (ꢄ) calculated from the desorption branch of the isotherms using the
[
4
BJH algorithm.

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J. Zhang et al. / Materials Research Bulletin 45 (2010) 1648–1653
Fig. 5. TEM images of (a) Post-CP-SBA-15, (b) Post-PdTSPP-PMIM-SBA-15, and (c) used Post-PdTSPP-PMIM-SBA-15 after 9 runs.
anions, the typical mesophase maintains well without observable
difference. Moreover, the absence of aggregated Pd nanoparticles
indicates the high dispersion of [PdTSPP] ions in the channels of
host SBA-15. The TEM observations are consistent to the PXRD and
due to high loading of Pd-catalyst (1.37 wt%) and well-retained
SBA-15 structure (Table 2). The homogeneous catalyst of
4
ꢀ
[PdTSPP]Na
carried out under solvent-free condition, the liquid organic amine of
Et N was preferred as the base. Under mild conditions, 91% yield
of trans-ethyl cinnamate was obtained in aerial atmosphere when
homogeneous catalyst [PdTSPP]Na was applied (Entry 1). Based on
4
was used as comparison. Since the reaction was
N
2
sorption isotherms results.
3
The characterizations of one-pot-synthesized materials (One-
pot-CP-SBA-15, and One-pot-PdTSPP-PMIM-SBA, see Figs. S1–S4
and Table S1 in Supplementary Information) reveal that SBA-15
mesoporous framework can be retained but with dramatic decrease
of long-range order (Fig. S1(c) and Fig. S4(b)). When using one-pot
synthesis method without calcining the materials at 550 8C, the
relatively frail framework of SBA-15 could be destructed badly
during the further modification or solvent treatment.
4
the same concentration benchmark, Post-PdTSPP-PMIM-SBA-15
exhibited better activity (Entry 2), probably due to the individual
4ꢀ
isolation of [PdTSPP] catalytic sites in the channels of SBA-15,
4ꢀ
which blockedthe aggregation of [PdTSPP] itself usually occurring
in homogeneous processes [36]. Upon completion, the reaction
mixture was extracted by ethyl ether. The left solid could be reused
directly. However, after 3 runs, the conversion of iodobenzene
decreased to 72% (Entry 4). The ICP-AES analysis indicated that the
leaching of Pd in the combined organic phase after 3 runs was
3.2. Catalytic performance
Post-PdTSPP-PMIM-SBA-15 was selected to catalyze the Heck
reaction of iodobenzene with ethyl acrylate as a model reaction,
beyond the limit of detection (<0.1 mg/g). The UV–visible spectra
4ꢀ
also indicated that the loss of [PdTSPP] in the liquid phase was
non-detectable. These results ruled out any involvement of
palladium species that leached out of Post-PdTSPP-PMIM-SBA-15
catalyst into the liquid phase (which guaranteed the observed
catalysis was truly heterogeneous in nature). The UV–visible spectra
(Fig. S5(b) in Supplementary Information) showed that the used
Table 2
The Heck reaction of iodobenzene with ethyl acrylate catalyzed by Post-PdTSPP-
a
PMIM-SBA-15 .
b
Entry
Catalyst
Yield (%)
Post-PdTSPP-PMIM-SBA-15 was as intact as the fresh one in term of
1
2
3
4
[PdTSPP]Na
4
(fresh)
91
100
86
72
88
91
85
85
84
73
79
76
6
4ꢀ
[
PdTSPP]
character. However, in FT-IR spectra (Fig. S6(b) in
PdTSPP-PMIM-SBA-15-II (fresh)
PdTSPP-PMIM-SBA-15-II (2nd run)
PdTSPP-PMIM-SBA-15-II (3rd run)
PdTSPP-PMIM-SBA-15-II (4th run)
PdTSPP-PMIM-SBA-15-II (5th run)
PdTSPP-PMIM-SBA-15-II (6th run)
PdTSPP-PMIM-SBA-15-II (7th run)
PdTSPP-PMIM-SBA-15-II (8th run)
PdTSPP-PMIM-SBA-15-II (9th run)
ꢀ
1
SupplementaryInformation), a strongpeakat1733 cm ascribedto
C 55 O vibration was observed, which revealed that the surface of
Post-PdTSPP-PMIM-SBA-15 was covered by the absorbed trans-
ethyl cinnamate, leading to inaccessibility of the substrate to the
catalyticsite and then the dropped activity. Hence, the leftsolid after
c
5
6
7
8
9
3
the 3rd run (Entry 4) was washed with CH CN and EtOH thoroughly
10
11
12
13
before continuous uses. Consequently, the activity of the resultant
brick-red catalyst was almost recovered as shown in Entries 5–9
[PdTSPP]Na
[PdTSPP]Na
[PdTSPP]Na
4
4
4
-SBA-15 (fresh)
-SBA-15 (2nd run)
-SBA-15 (3rd run)
(Table 2). The TEM image in Fig. 5(c) also indicated that the used
Post-PdTSPP-PMIM-SBA-15 after 9 runs retained as intact as the
a
Pd concentration 0.1 mol%, iodobenzene 0.5 mmol, Et
3
N 1.0 mmol, ethyl
4ꢀ
fresh one in terms of SBA-15 mesoporous structure and [PdTSPP]
acrylate 1.0 mmol, temperature 130 8C, time 3 h.
b
dispersion.
GC yields to trans-ethyl cinnamate.
c
In contrast, when [PdTSPP]Na
4
-SBA-15 was used as the catalyst
3
The used Post-PdTSPP-PMIM-SBA-15 after the 3rd run was washed with CH CN
and EtOH before next run.
(Entries 11–13 of Table 2), the activity lost rapidly during recycling.

J. Zhang et al. / Materials Research Bulletin 45 (2010) 1648–1653
1653
Table 3
lyst towards the Heck reaction of aryl iodides/bromides and ethyl
acrylate in absence of any organic ligand and organic solvent,
which could be recovered and recycled 9 times without SBA-15
structural collapse, Pd species leaching, and obvious activity loss.
Heck reaction of aryl halides with ethyl acrylate catalyzed by Post-PdTSPP-PMIM-
a
SBA-15
[TD$INLINE]
Acknowledgements
.
b
Entry
R
X
Yield (%)
The research work was financially supported by the National
Natural Science Foundation of China (No. 20673039), the Science &
Technology Commission of Shanghai Municipality (No.
09JC1404800), the Ministry of Science & Technology of China for
Crotian-Chinese Scientific and Technological Cooperation, and the
Fundamental Research Funds for the Central Universities.
1
2
3
4
5
6
7
8
9
p-CH
3
I
100
82
m-CH
p-OCH
m-OCH
p-NO
m-NO
p-CF
3
I
3
I
100
93
3
I
2
I
100
100
100
100
<5
83
2
I
3
I
m-CF
3
I
H
Br
Br
Br
Br
Br
10
11
12
13
p-NO
2
Appendix A. Supplementary data
p-CF
3
92
p-CH
3
<5
<5
p-OCH
3
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.materresbull.2010.07.006.
References
a
3
Cat 0.1 mol%, substrate 0.5 mmol, Et N 1.0 mmol, ethyl acrylate 2 mmol,
temperature 140 8C, reaction time 4 h.
b
GC yields to trans-coupling products (the products were confirmed by GC-
Mass).
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