Active immobilized palladium catalyst based on multiporous amphiphilic graft copolymer

Article abstract of DOI:10.1016/j.reactfunctpolym.2011.07.006

Poly(vinylidene fluoride)-g-poly(dimethylaminoethyl methacrylate) (PVDF-g-PDMAEMA)/camphor system produces thermoreversible gel and leaching of camphor with cyclohexane yields amphiphilic multiporous material characterized from scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and nitrogen adsorption porosimetry. Pd nanoparticles (Pd NPs, dia. 2.5-4.5 nm) are grown on this porous material by adsorption of Pd(OAc)₂ followed by reduction with hydrazine. MIP and nitrogen porosimetry show that the xerogels are multiporous in nature and the pore size decreases in the Pd NPs captured sample. The BET surface area of the Pd NPs captured dried gel (24.3 m ² g^-1) is lower than that of pure gel (32.5 m² g^-1) due to the blocking of some pores by Pd NPs. The Pd NPs captured amphiphilic porous PVDF-g-PDMAEMA act as an effective catalyst for aerobic ligand free Suzuki coupling of aryl halides (X = I, Br and Cl) in aqueous medium.

Full text of DOI:10.1016/j.reactfunctpolym.2011.07.006

Reactive & Functional Polymers 71 (2011) 1045–1054
Contents lists available at ScienceDirect
Reactive & Functional Polymers
journal homepage: www.elsevier.com/locate/react
Active immobilized palladium catalyst based on multiporous amphiphilic
graft copolymer
⇑
Sanjoy Samanta, Rama K. Layek, Arun K. Nandi
Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 19 May 2011
Received in revised form 12 July 2011
Accepted 14 July 2011
Available online 21 July 2011
Poly(vinylidene fluoride)-g-poly(dimethylaminoethyl methacrylate) (PVDF-g-PDMAEMA)/camphor sys-
tem produces thermoreversible gel and leaching of camphor with cyclohexane yields amphiphilic multi-
porous material characterized from scanning electron microscopy (SEM), mercury intrusion porosimetry
(
MIP) and nitrogen adsorption porosimetry. Pd nanoparticles (Pd NPs, dia. 2.5–4.5 nm) are grown on this
porous material by adsorption of Pd(OAc) followed by reduction with hydrazine. MIP and nitrogen
porosimetry show that the xerogels are multiporous in nature and the pore size decreases in the Pd
2
Keywords:
Graft copolymer
Porosimetry
Multiporous material
Pd-nano particle
Suzuki coupling
2
ꢀ1
NPs captured sample. The BET surface area of the Pd NPs captured dried gel (24.3 m g ) is lower than
2
ꢀ1
that of pure gel (32.5 m g ) due to the blocking of some pores by Pd NPs. The Pd NPs captured amphi-
philic porous PVDF-g-PDMAEMA act as an effective catalyst for aerobic ligand free Suzuki coupling of aryl
halides (X = I, Br and Cl) in aqueous medium.
Ó 2011 Elsevier Ltd. All rights reserved.
1
. Introduction
poor thermal stability and high susceptibility towards chemicals
are the causes of limitation for their application [41a] as a porous
Porous materials have attracted widespread attention because
of their increased potential application in heterogeneous catalysis
1–6], super adsorbents [7,8], optoelectronic devices [9,10], ultra
support of catalysts. So, multiporous materials with hydrophobic
bulk and hydrophilic pore would be an ideal choice for the support
of a catalyst. The multiporous materials find great application in
heterogeneous catalysis as micro- and mesopores provide the size
and shape selectivity for the guest molecules, and the macroporous
channels permit improved access to active sites avoiding pore
blocking by reagents or products.
We have chosen poly(vinylidene fluoride) (PVDF) as hydropho-
bic bulk material for its significant piezo and pyroelectric properties
[42], good biocompatibility [43], excellent chemical resistivity, and
good thermal stability [44]. One main strategy to modify PVDF
surface is by grafting hydrophilic polymer to prepare amphiphilic
PVDF [41,45,46] using atom transfer radical polymerization (ATRP)
for its robust nature [47]. Recently, we have used solution based
method to graft N,N-dimethylaminoethyl methacrylate (DMAEMA)
by ATRP technique (Scheme 1) [48]. One strategy of preparing
multiporous polymeric materials is making thermoreversible gels
followed by careful drying while keeping the polymeric network
intact [32,33,40]. Since PVDF produces thermoreversible gel with
various >C@O containing organic gelators through the polymer–sol-
[
low dielectric materials [11,12], sensors [13–15], sorption pro-
cesses [16–18], size selective separation [19–21], hosts for synthe-
sis of nano-objects [22], tissue engineering [23,24], photonics [25],
drug delivery [26–28], medical diagnosis [29], etc. For specific uses
porous materials of particular pore diameters and chemical charac-
teristics are required. According to IUPAC convention, they are
classified as micro, meso, and macro having diameter <2 nm, be-
tween 2–50 nm and >50 nm, respectively [5,30]. The presence of
all types of pores in the same material is referred as multiporous
materials [31–36], having applications in the field of catalysis,
chromatography, drug release, separation of large molecules, puri-
fication and recycling of municipal and industrial waste water, etc.
[
30,31,35,36].
In the literature, there are some reports of inorganic multiporous
materials [31,35,37–39]; however, the polymeric multiporous
materials are very few [32–34,40]. Again, the multiporous poly-
meric materials are mainly based on hydrophobic polymers, causing
fouling due to the interaction of organics in the feed water with the
typically hydrophobic pore surface [41]. But the fouling property
arising from the hydrophilic polymeric materials would be lesser
than that of hydrophobic one. However, low mechanical property,
2
vent complex formation from the interaction between >CF of PVDF
and >C@O group of gelator [49,50a], it is also expected that PVDF-g-
PDMAEMA (P-g-D), would form thermoreversible gel with camphor,
(1,7,7-trimethylbicyclo[2,2,1]heptane-2-one),
a bicyclic volatile
solid gelator for PVDF. After removal of camphor in a proper way,
multiporous polymeric materials with PVDF backbone and hydro-
philic pore surface would be expected.
⇑
Corresponding author. Tel.: +91 3324734971; fax: +91 3324732805.
E-mail address: psuakn@mahendra.iacs.res.in (A.K. Nandi).
1
381-5148/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.reactfunctpolym.2011.07.006

1
046
S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
R1
F
F
F
F
F
F
F
F
F
F
F
F
R2
R1
+ CuCl/L
CuFCl/L +
.
CH
F
F
C
.
2
Monomer
F
F
(M)
R
2
M
F
F
F
F
F
F
R1
R1
R1
R1
CuFCl/L
CuX/L +
CH
F
C
CH2
n-1
C
CH
F
CH2
n-1
.
R
2
2
X
2
C
C
F
R2
R2
F
R2
X= Cl or F
R
1
= -CH
3
2
and R = -COOCH
2
CH
2
NMe
2
′
′
L= 4,4 -dimethyl-2,2 -dipyridyl (DMDP)
Scheme 1. Mechanism of PVDF-g-PDMAEMA formation using the ATRP method.
Heterogeneous catalysis using multiporous polymeric materials
surface-to-volume ratio [56b–d]. The use of palladium complexes
such as pincer complexes [57b] or phosphine-based complexes
[57c] in catalysis is also reported in the literature although a strong
and toxic chelating agent and highly non-aqueous medium is
required due to their moisture sensitivity and so harmful for envi-
ronment. In addition they are difficult to recycle. Thus ligand free,
aqueous mediated coupling reaction catalyzed by recyclable por-
ous polymer-capped-Pd NPs is a green method, fruitful from both
environmental as well as economical points of view. Here we
report amphiphilic multiporous polymeric materials prepared
from P-g-D graft co-polymer using camphor as a solid gelator fol-
lowed by leaching with cyclohexane. The presence of DMAEMA
causes the material to be well dispersed and high binding capabil-
ity with Pd in water. Finally, a use of this Pd NPs embedded
amphiphilic multiporous material as an efficient heterogeneous
catalyst for aerobic ligand free Suzuki coupling of aryl halides
(X = I, Br and Cl) in aqueous medium is demonstrated. The catalyst
not only activates aryl iodides at 30 °C and aryl bromides at 100 °C
in absence of cetyl trimethyl ammonium bromide, CTAB (and at
30 °C in presence of CTAB) but also activates aryl chlorides at
100 °C in presence of CTAB in water.
is very uncommon, and recently, we have prepared palladium
nanoparticles (Pd NPs) supported fibrillar network of porous
b-PVDF from the novel gel nanocomposite route for efficient heter-
ogeneous catalytic oxidation and reduction reactions [51]. How-
ever, during the cross-coupling of aryl-halides and aryl-boronic
acids (Suzuki coupling), the catalyst fails. The poor dispersion of
the catalyst in water and low catalytic activity towards aryl-bro-
mides and chlorides due to hydrophobicity of PVDF and absence
of any ligand may be the causes of above failure [52a]. We propose
that in amphiphilic multiporous polymeric material with suitable
functional group, the catalytic activity of a Pd-heterogeneous cata-
lyst towards Suzuki coupling is expected to be very high in water,
even in absence of external ligands. The presence of functional
group(s) present in PDMAEMA part may bind and stabilize the
reactive palladium species [52b], avoiding agglomeration or leach-
ing through out the reaction in water and thus helping in Suzuki
coupling of aryl halides. Among the other Pd catalyzed reactions,
Suzuki coupling is the most easy and fundamental method in or-
ganic chemistry for the synthesis of pharmaceutically important
bi-aryl derivatives which are the main components of biologically
active and functional molecules [53a,b]. It promotes us to choose
Suzuki coupling reaction to test the performance of the Pd NP cat-
alyst embedded on amphiphilic porous polymer support.
2
+
2. Experimental section
Although a number of solid materials have been employed as
supports for palladium heterogeneous catalysts in the coupling
reactions of aryl bromides or iodides [53–57]; only a very limited
number of such palladium catalysts have been reported for cou-
pling reactions with aryl chlorides [58–61]. This may be due to
the fact that, the activation of CACl bond is much difficult than
CABr and CAI bonds, and in general requires drastic reaction con-
ditions like very high temperature, tailored ligands, hazardous
organic solvents, etc. To our knowledge, there are no reports of
using amphiphilic multiporous polymeric materials as solid sup-
ports for Pd NPs in Suzuki coupling. There are some reports
2.1. Materials
4
PVDF (Aldrich, USA, M ¼ 7:0 ꢁ 10 , polydispersity index 2.57,
n
head to head (H–H) defect = 4.33 mol%) was purified by recrystal-
lization from its 0.2% (w/w) solution of acetopheone. The monomer
DMAEMA (Acros Organics, New Jersey, USA) was purified by pass-
ing through basic alumina column. N-methyl-2-pyrrolidone (NMP)
(Loba Chemicals, Mumbai) was distilled and stored in argon atmo-
0
0
sphere. 4,4 -dimethyl-2,2 -dipyridyl (DMDP, Aldrich, USA) was
used as received. CuCl (Aldrich) was purified by washing with
10% HCl in water followed by methanol and diethyl ether in a
Schlenk tube under a nitrogen atmosphere. DL-camphor (S.D. Fine
Chem Ltd., Mumbai) was purified by a sublimation procedure.
[
56b–d] discussing the advantage of Pd nanoparticles (NPs) on
catalysis over usual Pd catalysts. Particularly, the Pd NPs show
enhanced catalytic efficiency over the bulk Pd material due to their
better electron transfer ability during coupling reactions and large
Palladium acetate [Pd(OAc) ], aryl halides and boronic acids
(Aldrich) were used as received without further purification.
2

S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
1047
2.2. Preparation of PVDF-g-PDMAEMA graft co-polymer
1 cm quartz cell using a UV–vis spectrophotometer (H.P, model
453).
8
A nitrogen purged reaction vessel containing 20% (w/v) NMP
solution of PVDF, DMDP and CuCl were added. The mole ratio of
PVDF, DMDP and CuCl was 0.07:3.2:1. The monomer DMAEMA
2.5.2. FT-IR
The FTIR spectra of the PD/camphor gel and different porous
(
volume ratio of NMP and DMAEMA 1.25:1) was next introduced
materials are obtained from a Shimadzu FT-IR (model 8400S)
instrument. The sample was mixed with solid KBr and pellets were
used to scan the sample.
into the tube followed by nitrogen purging for 15 min after which
the tube was closed with a rubber septum. The tube was then
placed in an oil bath (90 °C) with constant stirring. After 24 h,
the content of the tube was diluted with small amount of NMP
and poured into excess pet ether (60–80 °C). The separated poly-
mer was isolated, re-dissolved in NMP and precipitated into pet
ether. The polymer was then washed repeatedly with double dis-
tilled water followed by drying in vacuum at room temperature
The average graft length of the graft copolymer is 30 monomer
unit, graft density (i.e., grafting sites per PVDF chain) = 15.6. The
molecular weight of the graft copolymer is 142,000 [48].
2.5.3. AAS
Atomic Absorption Spectroscopic (AAS) measurements were
carried out by using a Shimadzu AA-6300 AAS spectrometer fitted
with a double beam monochromator.
2.6. Wide-angle X-ray scattering (WAXS)
The wide-angle X-ray diffraction experiments of the gel and dif-
ferent porous materials were performed with a Bruker AXS D8 Ad-
vanced diffractometer using Cu Ka (k = 0.15406 nm) radiation. The
instrument was calibrated with a standard silicon sample. The
2.3. Preparation of multiporous material
samples were scanned from 2h = 2°–37° at the step scan mode
The multiporous material was prepared in a two step processes.
(
step size 0.03°, preset time 2 s), and the diffraction pattern was re-
corded using a scintillation counter detector.
2.3.1. Gelation
The amphiphilic P-g-D graft co-polymer and camphor with
appropriate amounts were taken in a thick-walled glass tube and
was sealed. The sample in the sealed tube was then melted at
95 °C in an oil bath for 20 min with intermittent shaking using
a rotor (Remi, Cyclo-Mixer) to make transparent homogeneous
2
.7. Microscopy
(
i) The morphology of the P-g-D/camphor systems was studied
1
from a thin portion of the dried gels after platinum coating in a
field emission scanning electron microscope (FESEM; JEOL, JSM-
6
solution followed by quenching to 30 °C to form the gel.
700F). (ii) For TEM study, a drop of aqueous dispersion of Pd
NPs was taken on a carbon coated copper grid (200 mesh) followed
by drying in air and finally in vacuum at 30 °C. The micrographs
were taken through a high-resolution transmission electron micro-
scope (JEOL, 2010 EX). The instrument was operated at an acceler-
ation voltage of 200 kV without staining. A CCD camera was used
to record the pictures. The diameter of the nanoparticles was
measured using photoshop software and taking average over 100
particles from different spots.
2
.3.2. Drying of gel
The P-g-D/camphor gel is kept immersed in cyclohexane for
–10 days to replace camphor by cyclohexane. To drive the above
8
replacement process quickly, the cyclohexane was replaced by a
fresh batch after every 12 h. After total extraction of camphor, it
was first dried in air and finally in vacuum at 30 °C for 3 days.
2
.4. Immobilization of Pd NPs
2.8. Thermal measurements
2
In a 50 ml flask 20 mg Pd(OAc) and 15 ml double distilled
water were taken with nitrogen purging for 30 min and then the
flask was closed with a rubber septum, followed by sonication in
a ultrasonic bath (60 W, model AVIOC, Eyela) for 2 h and stirring
overnight in dark. 1 g of amphiphilic multiporous P-g-D polymer
was then added and stirring is continued in dark in nitrogen atmo-
sphere. After 24 h, the polymer was separated, washed with double
distilled water (10 times) and the total filtrate thus obtained was
used for Atomic Absorption Spectroscopy (AAS) study for indirect
The thermal behavior of the systems was investigated by a differ-
ential scanning calorimeter (DSC, Diamond DSC-7, Perkin–Elmer,
USA) under nitrogen atmosphere. The gels were prepared in
Perkin–Elmer large volume capsules (LVC) by taking a weighed
amount of polymer, and camphor and the capsules were tightly
sealed with a quick press. They were homogenized at 200 °C for
0 min and were quenched to 50 °C where it was equilibrated for
0 min. They were heated at the scan rate of 10° and 40°/min from
0 to 200 °C. Cooling runs were also taken from the melt at 200–
0 °C at the rate of 5 °C/min. The weight of the sample pan was
1
2
5
5
2 2
calculation of Pd(OAc) bound by porous polymer. The Pd(OAc)
bound polymer is then dispersed in 50 ml distilled water, 2 ml of
hydrazine was added followed by stirring at 50 °C for 2 h. The color
of the porous polymer turned into brownish-black, indicating the
formation of Pd NPs. After 2 h, the polymer was separated out,
washed with double distilled water for 10 times and the total fil-
checked after each experiment. The melting temperature and
enthalpy of fusion values were measured with the help of PYRIS
software (version 7.0).
3
trate thus obtained was boiled with concentrated HNO and used
again for AAS study, no Pd was detected in the filtrate. The Pd
NPs embedded porous materials was finally dried in vacuum at
2
.9. Porosity measurements
2
Both mercury intrusion porosimetry (MIP) and N adsorption
3
0 °C for 3 days for further catalytic applications.
porosimetry were used, the former was used to measure pore
diameter >6 nm using the instrument Poremaster 60 (Quanta-
chrome), and the later was used for pore diameter <6 nm using
Autosorb 1-2C instrument (Quantachrome). In the MIP two pres-
sure ranges e.g., low-pressure range (0.5–50 psi) and high-pressure
2
2
.5. Spectral characterization
.5.1. UV–vis
The UV–vis spectra of aqueous dispersion of the multiporous
range (20–34,000 psi) were used to measure pores >10
pores <10 m, respectively. Blank correction was made using
-Al beads. The sample was taken in a penetrometer (stem
lm and
P-g-D material, Pd(OAc)
2
bound porous material and Pd NPs
l
embedded porous material were taken from 190 to 1100 nm in
a
2 3
O

1
048
S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
3
volume 0.5 cm ) was kept at first at the low-pressure chamber, and
both intrusion and extrusion runs were recorded. After completion
of the experiment the penetrometer was transferred to a high-
pressure chamber with the replacement of a little mercury at the
stem by silicon oil, and the pressure was applied by hydraulic
means. MIP is based on the principle that nonwetting liquids
intrude into the capillaries under pressure (P) following the
Washburn equation:
NPs embedded amphiphilic multiporous material (15 mg) was
then added and stirring was continued for homogeneous disper-
sion and the reaction mixture was kept in a bath of required tem-
perature with constant stirring. The coupling reactions of aryl
iodides and bromides were performed at 30 and 100 °C, respec-
tively in absence of surfactant. In the presence of surfactant the
reactions of aryl bromides and chlorides were performed at 30
and 100 °C, respectively. The progress of the reaction was moni-
tored by thin layer chromatographic (TLC) analysis of the reaction
mixture. After the desired time, the reaction mixture was diluted
with 5 ml of water and the catalyst was separated by filtration.
The catalyst was first washed with water and then with diethyl
ether, dried in vacuum at room temperature for further use. The to-
ꢀ
2ccos h
P
r ¼
ð1Þ
where r is the radius of the pore,
c
is the surface tension, and h is the
contact angle of mercury (nonwetting liquid) with the solid sample.
The fraction of volume per unit mass occupied by the pores having
radii in the interval (r and r + dr) can be deduced from the volume of
mercury that intrudes within the pressure range (P and P + dP)
tal filtrate thus obtained is extracted with dry Et
extract was washed with brine and water and was dried over
Na SO . After evaporation of solvent, crude product was further
2
O and the ether
2
4
purified by column chromatography over silica gel and the % con-
version was determined. The purity of all compounds was also
dV ¼ ꢀD
V
ðrÞdr
ð2Þ
1
13
checked by H NMR and C NMR. Majority of the products are well
known compounds and hence, they are identified by comparing
where D
V
(r) refers to the volume pore size distribution function de-
fined as the pore volume per unit interval of pore radius per unit of
mass. Combining Eqs. (1) and (2), we have
1
13
their spectroscopic data ( H NMR and C NMR) with literature.
P dV
r dP
2
.10.2. Heterogeneity test
A catalytic reaction, as described above was performed using
DVðrÞ ¼ ð Þ
ð3Þ
3 4
phenylboronic acid, 4-bromo anisole, K PO and CTAB at 30 °C.
In nitrogen adsorption porosimetry we measured the pore size
and pore size distribution of the mesopores and micropores using
the BJH (Barett–Joyner–Halenda) and HK (Horvath–Kawazoe)
methods, respectively using Autosorb 1 software.
After 6 h (62% conversion) the catalyst was separated and the reac-
tion was continued with the filtrate only for another 18 h but no
reaction occurred due to the fact that there was no leached Pd-cat-
alyst in the filtrate.
2
2
.10. Catalytic application
3
. Result and discussion
.10.1. Catalytic reaction and recycling
Arylboronic acid (1.2 mmol), aryl halide (1.0 mmol), an inor-
3.1. Morphology
ganic base (2 mmol) and surfactant (1 mmol) (not for aryl iodides)
were taken in a 10 ml flask containing 2 ml distilled water
followed by stirring to make a near homogeneous solution. Pd
The FE-SEM pictures of dried gels at two different magnifica-
tions are presented in Fig. 1 and Suppl. Fig. 1 showing their porous
a
b
c
o
1
76.6 C
o
o
1
29.3 C
134.2 C
Heating
Cooling
0
9
1.1 C
0
1
68.3 C
80
100
120
140
160
180
200
0
Temperature ( C)
Fig. 1. (a) Low- and (b) high-magnification FESEM pictures of the P-g-D/camphor system (WP-g-D = 0.1) after the removal of camphor. (c) DSC heating and cooling
thermograms for the P-g-D/camphor system of composition WP-g-D = 0.1.

S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
1049
nature. Honeycomb type pores are present throughout the sample
with pore diameter 18–25 m as obtained from the low magnified
a
0.4
0.3
l
2
3 μm
picture of dried gel of composition WP-g-D = 0.1. The morphology of
low magnified picture of dried gel of composition WP-g-D = 0.25 is
somewhat different showing the presence of irregular honeycomb
type pores (Suppl. Fig. 1a) and it is totally different for WP-g-D = 0.4
where plum leaf type pores surrounded by large islands are
observed (Suppl. Fig. 1c). The walls of pores and the islands are also
porous, containing fibrillar network structure and nano-pores are
observed from their higher magnified pictures (right hand side of
Fig. 1 and Suppl. Fig. 1). In Fig. 1c the DSC heating and cooling ther-
mograms of the P-g-D gel (WP-g-D = 0.1) indicate reversible first
order phase transition. The fibrillar net work structure and revers-
ible first order phase transition characterize the system to behave
as thermoreversible gel [50]. The lower transition temperatures are
for the gel and the higher temperatures are for camphor. During
gelation, a fraction of camphor molecules are involved to form
P-g-D/camphor complex [34] and the rest of camphor molecules
are crystallized in a honeycomb type array of caged camphor mol-
ecules inside the gel. Micro-pores are produced from P-g-D/cam-
phor complexation whereas the macro-pores are originated from
the removal of caged camphor molecules inside the gel [34]. In
case of WP-g-D = 0.1, minimum amount of camphor forms complex
with P-g-D polymer leaving a large fraction as caged molecules
remaining inside the gel. This contributes to the continuous honey-
comb type pore formation and as the composition of gel gradually
increases from WP-g-D = 0.1 to WP-g-D = 0.4, larger fraction of cam-
phor forms complex and smaller amount of caged camphor
remains inside the gel decreasing the honeycomb type pore forma-
tion and its size. The islands at lower magnification images are
composed of fibrillar network structure being produced from
polymer solvent complexation and removal of the complexed
camphor yields nano-pores [34].
0.2
0.1
0.0
10
100
Diameter (μm)
0
0
0
0
.005
.004
.003
.002
b
0.018
0.001
0.000
0
.0063
0.0064
0.0065
Diameter (μm)
0.0066
0.0067
0.012
0
0
.006
.000
0.1
1
3.2. Porosity
Diameter (μm)
To obtain a quantitative result of porosity, both MIP and N
adsorption porosimetry for the dried gel of composition
P-g-D = 0.1 are made. From our previous work it is known that,
2
Fig. 2. MIP (a) low-pressure and (b) high-pressure pore-size distribution histo-
grams of the pure dry gel sample [inset of (b): MIP high-pressure pore-size
distribution curves of same sample in a different region].
W
the surface area of a dilute gel is always larger than that of concen-
trated gel [34]. Since we are interested to use the porous material
for heterogeneous catalysis and surface area has important role on
catalysis, we have chosen the dilute gel, WP-g-D = 0.1, for this pur-
pose. In Suppl. Fig. 2 the MIP histograms for both high pressure
and low pressure runs are presented and in the inset of Suppl.
Fig. 2a low pressure MIP histogram for larger pores is shown. The
low pressure MIP histogram is sharp in nature whereas for high
pressure it is somewhat broad. The sharp nature indicates that
the sample has narrow pore size distribution for larger pores.
The pore size distribution histograms for high pressure and low
pressure runs are plotted in Fig. 2. There is only one sharp peak
pores of ink-bottle-type structure. The BJH pore size distribution
curve is presented in Fig. 3b and it is apparent that there are pores
having pore diameter around 3.3 nm–28.6 nm in the sample. To
understand the presence of pores of lower diameter we have plotted
the HK pore size distribution curve (Fig. 3c) which shows micro-
pores of diameter 0.74, 1.15, 1.4, 1.51 and 1.73 nm. The sample
2
ꢀ1
has BET surface area 32.5 m g
.
3.3. Structure
The structure of dried gels is determined from the WAXS dif-
fraction patterns (Suppl. Fig. 3) and there are peaks at 2h = 17.9°,
at around 23
gram indicating that though there are pores of different sizes,
majority of pores have an average diameter of 23 m. These results
l
m in the low pressure pore size distribution histo-
18.6°, 20.2° and 26.8° corresponding to the
a polymorph of PVDF
l
[62–64]. We have also used FT-IR spectroscopy as an alternate tool
for this purpose (Suppl. Fig. 4) and the FT-IR spectra of solvent
subtracted gel and dried gel clearly indicate that PVDF mainly
match well with that obtained from the lower magnification FES-
EM picture of the sample. In the high pressure pore size distribu-
tion histogram there are peaks at 0.6, 4.9, 5.9 and 7.1
l
m,
exists in the a form both in the gel as well as in the dried gel (cor-
ꢀ
1
indicating the existence of smaller pores. In the inset of Fig. 2,
the high pressure pore size distribution histogram of very small
pores is shown indicating that pores of diameter ꢂ6 nm are also
present in the sample.
responding peak at 532, 613 and 796 cm ) with the existence of a
small fraction as b form also (corresponding peak at 510, 600 and
ꢀ
1
841 cm ) [65,66].
To understand the interesting feature of micro-pores and meso-
pores arising from polymer–solvent complexation [34], we have
3.4. Characterization of Pd NPs captured porous material
done the N
2
adsorption porosimetry (Fig. 3a) showing the presence
2
Due to the presence of ANMe group in the hydrophilic part of
of small hysteresis between intrusion and extrusion isotherms due
to the interconnectivity among the pores or due to the presence of
the pore surface, the amphiphilic multiporous graft co-polymer
(1 g) can bind 6.4 ꢁ 10 mmol (72% of 20 mg) palladium from
ꢀ2

1
050
S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
a 30
b
Adsorption for pure gel
(i) Dry gel (WP-g-D =0.1)
Desorption for pure gel
-
3
(ii) Pd(0) capped dry gel ( WP-g-D =0.1)
Adsorption for Pd(0) capped gel
Desorption for Pd(0) capped gel
1.2x10
2
2
1
1
5
0
5
0
5
0
8
.0x10-4
.0x10-4
4
i
ii
8
0.0
0.0
0.2
0.4
0.6
0.8
1.0
0
16
24
32
40
Relative Pressure (P /P )
S
O
Diameter (nm)
c
(i) Dry gel (WP-g-D=0.1)
(ii) Pd(0) capped dry gel (WP-g-D=0.1)
i
ii
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Pore diameter (nm)
Fig. 3. (a) BET adsorption and desorption isotherms, (b) BJH pore-size distribution curves and (c) HK pore-size distribution plots for the pure dry gel and the Pd NP-captured
dried gel samples.
the absorption band at 246 nm and 256 nm in the UV–vis
spectrum. The formation of Pd NPs in the porous material is con-
firmed from TEM images (Fig. 4a) and the histogram (Fig. 4b)
shows two major intense regions at approx. 2.92 nm and
ꢂ4.0 nm. Probably, Pd(II)-polymer complexation is responsible
for the formation of smaller Pd NPs (2.92 nm) and the larger NPs
(3.89–4.02 nm) are produced from the adsorbed Pd(OAc) . In this
2
polymer-supported Pd catalyst, there are two types of capping
agents for Pd NPs. One is the PVDF backbone which has capped
Table 1
Atomic-Absorption Spectroscopy data of Pd in 1 gm of mutiporous polymeric
material.
Amount of
Pd taken
Amount of Pd in the
filtrate (after immobilization
of Pd2 ) (mmol)
Amount of Pd in the
polymer (after immobilization
+
2+
(
mmol)
of Pd ) (mmol)
9 ꢁ 10ꢀ
3
24.9 ꢁ 10ꢀ3
64.1 ꢁ 10ꢀ3 ꢃ 72%
8
aqueous solution of palladium acetate at 24 h as indicated from
Atomic-Absorption Spectroscopy (AAS) data (Table 1). The binding
2
the Pd NPs by simple adsorption [51] and the other is >NMe group
of grafted PDMAEMA which has capped the Pd NPs through com-
plexation. The capping by complexation makes the PDMAEMA
shell more compact, hence there is difficulty in diffusion of Pd
atoms, causing lower dimension. Anyway, the dispersity of Pd
NPs is really small. The lattice spacing value (0.224 nm) matched
very well with that of 1 1 1 lattice plane of Pd metal [51,68] as evi-
denced from the HRTEM image (Suppl. Fig. 6a). The EDXS spectrum
of the material indicates the presence of metallic palladium in the
multiporous polymeric material (Suppl. Fig. 6b). The gel structure
and polymorph of PVDF remain unchanged after complexation
2
+
of Pd is supported by UV–vis spectrum (Suppl. Fig. 5). It is re-
ported that aqueous solution of Pd(OAc) shows a UV–vis absorp-
2
tion band at approximately at around 256 nm [67]. The UV–vis
spectrum clearly indicates that the aqueous dispersion of multi-
porous P-g-D showed two well absorption bands at around 297
⁄
⁄
and 307 nm for
p–p transition coupled with n–p transition,
2
+
whereas the Pd captured porous materials shows two additional
small peaks at 246 and 256 nm which may be due to the
Pd(II)-polymer complexation (246 nm) with PDMAEMA part along
2
+
with some adsorbed Pd(OAc)
2
(256 nm) onto the graft polymer
with Pd and its reduction to produce Pd NPs as evidenced from
the WAXS pattern (Suppl. Fig. 7) and FTIR spectra (Suppl. Fig. 8)
matrix. Bernechea et al. also obtained similar type of new band
at lower wavelength region due to palladium(II)-dendrimer com-
plexation [67]. Upon reduction with hydrazine the color of the
polymer changed from light yellow to brownish black indicating
the formation of Pd NPs inside the porous material. The formation
of Pd NPs in the porous materials is established from the absence of
2
+
of Pd and Pd NPs captured dried gels.
The Pd NPs captured dried gel (WP-g-D = 0.1) is also porous and
to obtain a quantitative idea of porosity, we have performed both
MIP and nitrogen adsorption porosimetry of it. Though the low
pressure MIP intrusion histogram of pure gel has one sharp peak,

S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
1051
a
a
0.4
0.3
0.2
0.1
0.0
10
100
Diameter (μm)
b 15
b
0
.02
.01
.00
1
0
5
0
0
0
2.5
3.0
3.5
d / nm
4.0
4.5
0.1
1
Diameter (μm)
Fig. 4. (a) TEM image of the Pd NPs in the porous material and (b) histogram of the
Pd NPs.
Fig. 5. MIP (a) low-pressure and (b) high-pressure pore-size distribution histo-
grams of the Pd NP-captured dry gel sample.
it is broad in case of Pd NPs captured dried gel (Suppl. Fig. 9a), indi-
cating the presence of wide range of large pores in the sample
whereas the high pressure MIP intrusion histogram of Pd NPs cap-
tured died gel (Suppl. Fig. 9b) is very similar with that of pure dried
gel. In the inset of Suppl. Fig. 9a, the low pressure MIP intrusion
histogram is plotted for Pd NPs captured dried gel which is an indi-
cation for the presence of pores of larger diameter. From the low
pressure pore size distribution histogram of Pd NPs captured dried
2
ꢀ1
the Pd NPs captured dried gel (24.3 m g ). Due to the presence
of pd nanoparticles in the Pd NPs captured dried gel, some pores
are blocked which is the main reason for lower BET surface area
of the sample than the pure gel. The BJH and HK pore size distribu-
tion of Pd NPs captured dried gel, shown in Fig. 3b and c, are sim-
ilar with those of pure gel but at lower position due to the blocking
by Pd nanoparticles as stated above.
gel (Fig. 5a) it is clear that there is a peak at about 22
m less than that of low pressure pore size distribution histo-
gram of pure dried sample (23 m). In addition of this, two humps
are present in the Pd NPs captured sample at around 12 m and
m, indicating the presence of smaller pores which are absent
in pure dry gel.
The porous material has a bi-functional hydrophilic side chain
lm, which is
1
l
3.5. Catalytic tests
l
l
With the P-g-D amphiphilic multiporous polymeric materials
supported Pd NPs in hand; we explore its catalytic activity towards
aerobic ligand free Suzuki coupling of aryl halides (X = I, Br and Cl)
in aqueous medium. We have tested the catalytic activity over var-
ious electron-withdrawing and electron-donating aryl halides at
high temperature (100 °C) as well as at room temperature (30 °C).
To optimize the reaction conditions, a model coupling reaction
between 4-bromoanisole and phenylboronic acid is chosen and it
acts as a benchmark to compare the activity of different palladium
catalysts in Suzuki reaction [53–57]. In 4-bromoanisole, the meth-
oxy group present at the para position, which is the cause of diffi-
culty in CAC bond formation via cross-coupling reaction, thus
providing an opportunity for comparing the catalytic activity of
different Pd-catalysts. The reaction is initially carried out with
Na CO as base in water at 100 °C with only 62% product in 24 h
17 l
2+
which is responsible for the binding of Pd from aqueous Pd(OAc)
2
solution. In the cyclohexane leached dried gel, all the hydrophilic
parts may not be present in the pore surface, but in aqueous med-
ium most of them endeavor at the pore surface (phase inversion).
Upon drying, the hydrophilic parts form a layer at the inner surface
of the pore, reducing the pore diameter than that of cyclohexane
dried pure gel. However, high pressure pore size distribution histo-
gram of Pd NPs captured sample has four peaks at 0.4, 5.3, 6.4 and
7
.3
lm which are slightly higher than that of pure gel (0.6, 4.9, 5.9
and 7.1
lm). The BET adsorption isotherm of the Pd NPs captured
dried gel (Fig. 3a) is at lower position than that of pure gel indicat-
2
3
ing some micropores are blocked due to inclusion of Pd NPs. The
BET surface area of pure gel is higher (32.5 m g ) than that of
(Table 2, entry 1). In the coupling reactions the nature of base is
very important and to obtain higher conversion, experiments using
2
ꢀ1

1
052
S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
Table 2
Standardization of base for the cross-coupling reaction of 4-bromoanisole (1 mmol) and phenylboronic acid (1.2 mmol) using 2 mmol base and 20 mg catalyst in 2 ml water.
OH
2 ml H
2
O
B
+ Br
OMe
OMe
OH
20 mg catalyst
Entry
Base (2 mmol)
Na CO
CO
KF
KOH
CsF
Temperature (°C)
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
9
2
3
100
100
100
100
100
100
100
100
50
24
24
24
24
24
24
16
10
16
16
62
80
78
65
88
96
94
70
52
35
K
2
3
3
K PO
3
K PO
3
K PO
3
K PO
3
K PO
4
4
4
4
4
1
0
30
different types of base are performed and the results are compared
in Table 2. From the table it is clear that the optimum yield (94%) is
achieved with K PO at 100 °C (Table 2, entry 7) for 16 h. of reac-
3 4
tion time. It is well established that the higher temperature facili-
tates the debromination product leading to lower selectivity [69],
which is the main reason for recent trend to perform the coupling
reactions at ambient temperature. The reaction (Table 2 entry 10)
clearly indicates that the catalyst can activate the 4-bromoanisole
even at room temperature (30 °C) with a lower yield (35%). The ef-
fect of surfactant on the coupling reaction with the mutiporous Pd
out of which the addition of CTAB enhances the transformation sig-
nificantly (Suppl. Table 1, entry 3) and the exact reason is unknown
to us. The influence of the amount of CTAB in the coupling reaction
is also optimized with the same model reaction showing a maxi-
mum yield with 1 mmol (Suppl. Table 2). Finally, we have tried
to find out the minimum amount of catalyst to obtain maximum
3 4
yield using optimized amount of K PO and CTAB. The best result
ꢀ
3
is obtained using 15 mg of catalyst (ꢂ10 mmol Pd) as indicated
from Suppl. Table 3.
After optimizing the model reaction in terms of base, nature of
surfactants, amount of surfactants and amount of catalyst, aryl
halides of different structures are employed for cross-coupling
reactions with phenylboronic acid using pre-optimized conditions
to obtain different substituted biaryls. The results are summarized
in Table 3 (characteristic NMR spectra of products in Suppl.
Fig. 10a–n) where the presence of an electron-donating or
withdrawing group on the aromatic ring of aryl bromides have
shown independency of reactivity, producing very good yield in
each case (>90%). We have also performed some reactions with
various aryl iodides without surfactant and interestingly, we have
3 4
catalyst in presence of K PO is tested with addition of small
amount (1 mmol) of them and the results are compared in Suppl.
Table 1. Tetra butyl ammonium bromide (TBAB) has increased
the reaction yield to 68%, (Suppl. Table 1, entry 1) from 35%. The
addition of TBAB improves the solubility of the reactants in water
[
70]. However, the increase of yield using TBAB encourages us to
carry out the model reaction at room temperature with better
yield. Thus, four different surfactants namely TBAB, tetra octyl
ammonium bromide (TOAB), cetyl trimethyl ammonium bromide
(
CTAB) and sodium dodecyl sulfonate (SDS) have been employed
Table 3
Pd NPs catalyzed cross-coupling reactions of aryl halides (1 mmol) and arylboronic acid (1.2 mmol) using 2 mmol K
aryl iodides) in 2 ml of water.
3 4
PO , 15 mg catalyst (0.1 mol% Pd) and 1 mmol CTAB (except
OH
K
3
PO
4
X
B
+
Catalyst
OH
R
R
Entry
R
X
Reaction temperature (°C)
Reaction time (h)
Surfactant
Yield (%)
Turnover number
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
H
I
I
I
I
30
30
30
30
30
30
30
30
30
14
12
18
12
12
10
10
12
10
16
14
24
24
24
24
24
No
No
No
No
90
92
93
97
92
93
95
96
98
95
92
44
65
26
71
67
900
920
930
970
920
930
950
960
980
950
920
440
650
260
710
670
4-Me
4-OMe
3-NO
H
3-NO
4-NO
4-CHO
4-COCH
4-OMe
4-Me
2
Br
Br
Br
Br
Br
Br
Br
Cl
Cl
Cl
Cl
Cl
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
2
2
3
1
1
1
1
1
1
1
30
30
H
100
100
100
100
100
4-COCH
4-OMe
4-NO
4-CHO
3
2

S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
1053
100
Pd NPs are grown on this porous material by adsorption of
Pd(OAc) in its aqueous dispersion followed by reduction with
2
hydrazine transforming the porous material brownish black. UV–
vis spectra indicate the formation of Pd NPs on the porous material
and the presence of Pd NPs within the amphiphilic porous material
is confirmed from HRTEM images and EDXS spectra. The sizes of Pd
nanoparticles vary from 2.5 to 4.5 nm. MIP low pressure pore size
distribution histogram of Pd NPs captured dried gel exhibit pore
8
6
4
2
0
0
0
0
0
diameters of ꢂ12, 17 and 22
sponding to pore diameter of 23
face area of the Pd NPs captured dried gel (24.3 m g ) is lower
lm, in contrast to a sharp peak corre-
l
m of pure dry gel. The BET sur-
2
ꢀ1
2
ꢀ1
than that of pure gel (32.5 m g ). The BJH and HK pore size dis-
tribution of Pd NPs captured dried gel are similar with those of
pure dried gel but at lower position due to reduced pore volume
by Pd NPs.
1
2
3
4
5
The Pd NPs captured amphiphilic porous PVDF-g-DMAEMA act
as an effective catalyst for aerobic ligand free Suzuki coupling of aryl
halides (X = I, Br and Cl) in aqueous medium. The catalyst not only
activates aryl iodides at 30 °C and aryl bromides at 100 °C in absence
of CTAB (and at 30 °C in presence of CTAB) but also activates aryl
chlorides at 100 °C in presence of CTAB in water. The catalyst shows
very good recyclability and is very effective even in the absence of
surfactant for aryl bromides and iodides. The higher activity of that
catalyst in aqueous medium is attributed to the multiporous and
hydrophilic nature of the polymer support.
Number of cycle
Fig. 6. Cyclic reaction diagram for Table 3, entry 10.
also obtained very high yield (>90%). With interest, we have also
checked the water mediated catalytic activity using aryl chlorides
under pre-standardized conditions at 100 °C. In this case, the cata-
lyst can trigger only the activated aryl chlorides with electron
withdrawing group showing moderate yield (65–71%), but the oth-
ers show an yield as low as 26%.
In general, the catalyst can activate all the aryl halides (X = I, Br
and Cl) in water with moderate to very high yield. The reactions
are very smooth and we have obtained different biaryls from aryl
iodides and bromides at room temperature in water, which is a
green approach; thus important from environmental as well as
from industrial points of view. The catalyst is air stable as evi-
denced from our series of reactions performed in aerobic condition
even up to five cycles (for reaction Table 3 entry 10) without any
appreciable loss of efficiency, shown in Fig. 6. The catalyst is highly
heterogeneous in nature and no dissolved catalyst is observed in
the filtrate as verified from the failure of reactions using filtrate
only.
Acknowledgments
We gratefully acknowledge Department of Science and Tech-
nology, New Delhi (Grant No. SR/S1/PC/26/2009) for financial sup-
port. R. K. L. thanks CSIR, New Delhi for the fellowship and we
acknowledge. Mr. R. Dey of Organic Chemistry department for
helping in reactions. We also acknowledge the help extended by
Central Glass and Ceramic Research Institute, Kolkata for their help
in MIP measurements.
Appendix A. Supplementary material
Again the reactivity of immobilized Pd NPs on porous polymer
is better than that of usual Pd NPs. As for example, the in situ gen-
erated Pd NPs can only activate the iodo- and bromo-aryl deriva-
tives but not the chloro-aryl derivatives during aqueous
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.reactfunctpolym.2011.07.006.
mediated Suzuki coupling reaction in presence of K
3
PO
4
as base
References
[
55c]. Here, we have used the same protocol with porous polymer
grafted Pd NPs which can activate the chloro-aryl derivatives.
Compared to the usual Pd catalysts or palladium complexes immo-
bilized Pd NPs on amphiphilic porous polymer causes (i) easier dis-
persion of the catalyst in water, (ii) facilitates the reaction in a
green condition, (iii) easy to process, (iv) the reaction is really fast
and finally (v) the yield is very high. So this present catalyst is ben-
eficial to the cross-coupling reactions and the present catalyst sys-
tem is inexpensive, eco-friendly, more reactive and recyclable it
offers a green method suitable for environment and industry.
[1] L. Chen, Y. Yang, D. Jiang, J. Am. Chem. Soc. 132 (2010) 9138–9143.
[
[
[
2] L.L. Welbes, R.C. Scarrow, A.S. Borovik, Chem. commun. (2004) 2544–2545.
3] Y. Zhang, S.N. Riduan, J.Y. Ying, Chem. Eur. J. 15 (2009) 1077–1081.
4] B. Karimi, A. Zamani, S. Abedi, J.H. Clark, Green Chem. 11 (2009) 109–119.
[5] X.S. Zhao, J. Mater. Chem. 16 (2006) 623–625.
[
[
6] K. Nakajima, I. Tomita, M. Hara, S. Hayashi, K. Domen, J.N. Kondo, Adv. Mater.
7 (2005) 1839–1842.
7] (a) H. Yoshitake, T. Yokoi, T. Tatsumi, Chem. Mater. 14 (2002) 4603–4610;
(b) N. Singh, J. Wang, M. Ulbricht, S.R. Wickramasinghe, S.M. Husson, J. Membr.
Sci. 309 (2008) 64–72.
1
[
[
8] O. Olkhovyk, M. Jaroniec, Ind. Eng. Chem. Res. 46 (2007) 1745–1751.
9] H. Peng, J. Tang, L. Yang, J. Pang, H.S. Ashbaugh, C.J. Brinker, Z. Yang, Y. Lu, J. Am.
Chem. Soc. 128 (2006) 5304–5305.
[
[
10] E. Coronado, E. Palomares, J. Mater. Chem. 15 (2005) 3593–3597.
11] Y. Xu, D.W. Zheng, Y. Tsai, K.N. Tu, B. Zhao, Q.Z. Liu, M. Brongo, C.W. Ong, C.L.
Choy, G.T.T. Sheng, C.H. Tung, J. Electron. Mater. 30 (2001) 309–313.
12] B. Zhao, Q.Z. Liu, M. Brongo, G.T.T. Sheng, C.H. Tung, Appl. Phys. Lett. 75 (1999)
4
. Conclusion
[
PVDF-g-DMAEMA/camphor system produces thermoreversible
853–855.
gel and leaching of camphor with cyclohexane produces multipor-
ous material as evident from SEM, MIP and nitrogen adsorption
porosimetry. Analysis of the adsorption data indicates that the
[
13] G. Korotcenkov, B.K. Cho, Crit. Rev. Solid State Mater. Sci. 35 (2010) 1–37.
[14] (a) L. Ying, P. Wang, E.T. Kang, K.G. Neoh, Macromolecules 35 (2002) 673–679;
(b) G. Zhai, L. Ying, E.T. Kang, K.G. Neoh, J. Mater. Chem. 12 (2002) 3508–3515;
c) J. Xue, L. Chen, H.L. Wang, Z.B. Zhang, X.L. Zhu, E.T. Kang, K.G. Neoh,
Langmuir 24 (2008) 14151–14158;
d) X. Liu, K.G. Neoh, E.T. Kang, Macromolecules 36 (2003) 8361–8367.
[15] J.H. Bang, S.H. Lim, E. Park, K.S. Suslick, Langmuir 24 (2008) 13168–13172.
(
dried gels have pore diameters ranging from 0.74 nm to 283 lm
and there is hysterisis between extrusion and intrusion isotherms
of nitrogen adsorption porosimetry indicating interconnection be-
tween mesopores and/or presence of inkbottle type pores. WAXS
and FTIR data clearly indicate presence of mainly
PVDF with a small fraction of b-PVDF in the material.
(
[
16] H. Kim, Y. Kim, M. Yoon, S. Lim, S.M. Park, G. Seo, K. Kim, J. Am. Chem. Soc. 132
2010) 12200–12202.
(
a-polymorph
[
17] Y.B. Zhang, W.X. Zhang, F.Y. Feng, J.P. Zhang, X.M. Chen, Angew. Chem. Int. Ed.
48 (2009) 5287–5290.

1
054
S. Samanta et al. / Reactive & Functional Polymers 71 (2011) 1045–1054
[
[
18] C. Martin, N. Tosi-Pellenq, J. Patarin, J.P. Coulomb, Langmuir 14 (1998) 1774–
778.
19] P. Roy, T. Dey, K. Lee, D. Kim, B. Fabry, P. Schmuki, J. Am. Chem. Soc. 132 (2010)
893–7895.
(d) D. Dasgupta, S. Malik, A. Thierry, J.M. Guenet, A.K. Nandi, Macromolecules
39 (2006) 6110–6114;
(e) P.J.P. Yadav, G. Ghosh, M. Maiti, V.K. Aswal, P.S. Goyal, P. Maiti, J. Phys.
Chem. B 112 (2008) 4594–4603.
1
7
[
[
[
20] K.A. Cychosz, R. Ahmad, A.J. Matzger, Chem. Sci. 1 (2010) 293–302.
21] G. Zhang, Z. Ruan, S. Ji, Z. Liu, Langmuir 26 (2010) 4782–4789.
22] A. Fukuoka, H. Araki, Y. Sakamoto, N. Sugimoto, H. Tsukada, Y. Kumai, Y.
Akimoto, M. Ichikawa, Nano Lett. 2 (2002) 793–795.
23] S.J. Hollister, Nat. Mater. 4 (2005) 518–524.
24] H. Zhang, A.I. Cooper, Soft Matter 1 (2005) 107–113.
25] Y.Y. Li, F. Cunin, J.R. Link, T. Gao, R.E. Betts, S.H. Reiver, V. Chin, S.N. Bhatia, M.J.
Sailor, Science 299 (2003) 2045–2047.
26] P. Horcajada, C. Serre, M. Vallet-Regi, M. Sebban, F. Taulelle, G. Ferey, Angew.
Chem. Int. Ed. 45 (2006) 5974–5978.
27] M. Vallet-Regí, F. Balas, M. Colilla, M. Manzano, DrugMetab. Lett. 1 (2007)37–40.
28] E.J. Anglin, L. Cheng, W.R. Freeman, M.J. Sailor, Adv. Drug Deliv. Rev. 60 (2008)
[50] (a) D. Dasgupta, S. Manna, S. Malik, C. Rochas, J.M. Guenet, A.K. Nandi,
Macromolecules 38 (2005) 5602–5608;
(b) C. Daniel, C. Dammer, J.M. Guenet, Polym. Commun. 35 (1994) 4243–4246.
[51] S. Samanta, A.K. Nandi, J. Phys. Chem. C 113 (2009) 4721–4725.
[52] (a) N. Hadei, E.A.B. Kantchev, C.J. O’Brien, M.G. Organ, Org. Lett. 7 (2005) 1991–
1994;
(b) B. Ochiai, Y. Shimada, React. Funct. Polym. 71 (2011) 791–795.
[53] (a) L.J. Gooben, G. Deng, L.M. Levy, Science 313 (2006) 662–664;
(b) N. Miyaura, A. Suzuki, Chem. Rev. 95 (1995) 2457–2483;
(c) M.N. Nadagouda, V. Polshettiwar, R.S. Varma, J. Mater. Chem. 19 (2009)
2026–2031;
[
[
[
[
[
[
(d) S. Fujii, S. Matsuzawa, Y. Nakamura, A. Ohtaka, T. Teratani, Langmuir 26
(2010) 6230–6239;
1
266–1277.
[
[
29] M.E. Davis, Nature 417 (2002) 813–821.
30] G.J. Soler-Illia, A.A. De, C. Sanchez, B. Lebeau, J. Patarin, Chem. Rev. 102 (2002)
(e) Y. Jang, J. Chung, S. Kim, S.W. Jun, B.H. Kim, D.W. Lee, B.M. Kim, T. Hyeon,
Phys. Chem. Chem. Phys. 13 (2011) 2512–2516.
4
093–4138.
[54] (a) C. Schmoger, T. Szuppa, A. Tied, F. Schneider, A. Stolle, B. Ondruschka,
ChemSusChem 1 (2008) 339–347;
[
[
[
[
[
[
31] J.H. Smått, S. Schunk, M. Linden, Chem. Mater. 15 (2003) 2354–2361.
32] D. Dasgupta, A.K. Nandi, Macromol. Symp. 222 (2005) 81–86.
33] D. Dasgupta, A.K. Nandi, Macromolecules 38 (2005) 6504–6512.
34] D. Dasgupta, A.K. Nandi, Macromolecules 40 (2007) 2008–2018.
35] Y. Ding, J. Erlebacher, J. Am. Chem. Soc. 125 (2003) 7772–7773.
36] (a) B.V. Bhut, S.R. Wickramasinghe, S.M. Husson, J. Membr. Sci. 325 (2008)
(b) S.E. Lyubimov, A.A. Vasil’ev, A.A. Korlyukov, M.M. Ilyin, S.A. Pisarev, V.V.
Matveev, A.E. Chalykh, S.G. Zlotin, V.A. Davankov, React. Funct. Polym. 69
(2009) 755–758;
(c) K. Zhan, H. You, W. Liu, J. Lu, P. Lu, J. Dong, React. Funct. Polym. 71 (2011)
756–765.
1
76–183;
[55] (a) K. Chattopadhyay, R. Dey, B.C. Ranu, Tetrahedron Lett. 50 (2009) 3164–
3167;
(
(
(
b) B.V. Bhut, S.M. Husson, J. Membr. Sci. 337 (2009) 215–223;
c) P. Wang, K.L. Tan, E.T. Kang, K.G. Neoh, J. Mater. Chem. 11 (2001) 783–789;
d) Y. Chen, L. Ying, W. Yu, E.T. Kang, K.G. Neoh, Macromolecules 36 (2003)
(b) M. Mora, C.J. Sanchidrián, J.R. Ruiz, J. Colloid Interf. Sci. 302 (2006) 568–
575;
9
451–9457.
37] L. Huang, Z. Wang, J. Sun, L. Miao, Q. li, Y. Yan, D. Zhao, J. Am. Chem. Soc. 122
2000) 3530–3531.
38] K.H. Rhodes, S.A. Davis, F. Caruso, B. Zhang, S. Mann, Chem. Mater. 12 (2000)
832–2834.
(c) D. Saha, K. Chattopadhyay, B.C. Ranu, Tetrahedron Lett. 50 (2009) 1003–
1006.
[56] (a) T. Maegawa, Y. Kitamura, S. Sako, T. Udzu, A. Sakurai, A. Tanaka, Y.
Kobayashi, K. Endo, U. Bora, T. Kurita, A. Kozaki, Y. Monguchi, H. Sajiki, Chem.
Eur. J. 13 (2007) 5937–5943;
[
[
[
(
2
39] B. Lebeau, C.E. Fowler, S. Mann, C. Foucer, B. Charleux, C. Sanchez, J. Mater.
Chem. 10 (2000) 2105–2108.
40] S. Malik, D. Roizard, J.M. Guenet, Macromolecules 39 (2006) 5957–5959.
41] (a) J.F. Hester, P. Banerjee, A.M. Mayes, Macromolecules 32 (1999) 1643–1650;
(b) A. Roucoux, J. Schulz, H. Patin, Chem. Rev. 102 (2002) 3757–3778;
(c) D. Astruc, F. Lu, J.R. Aranzaes, Angew. Chem. Int. Ed. 44 (2005) 7852–7872;
(d) D. Astruc, Inorg. Chem. 46 (2007) 1884–1894.
[
[
[57] (a) A.N. Vasiliev, L.V. Golovko, V.A. Povazhny, E. Zlotnikov, J. Chen, J.G. Khinast,
Microporous Mesoporous Mater. 101 (2007) 342–347;
(b) N. Selander, K.J. Szabo, Chem. Rev. 111 (2011) 2048–2076;
(c) L.C. Liang, P.S. Chien, M.H. Huang, Organometallics 24 (2005) 353–357.
[58] (a) R. Dey, B. Sreedhar, B.C. Ranu, Tetrahedron 66 (2010) 2301–2305;
(b) S. Schweizer, J.M. Becht, C.L. Drian, Org. Lett. 9 (2007) 3777–3780.
[59] R.K. Arvela, N.E. Leadbeater, Org. Lett. 7 (2005) 2101–2104.
[60] M. Choi, D.H. Lee, K. Na, B.W. Yu, R. Ryoo, Angew. Chem. Int. Ed. 48 (2009)
3673–3676.
(
7
(
b) A. Akthakul, R.F. Salinaro, A.M. Mayes, Macromolecules 37 (2004) 7663–
668;
c) J.F. Hester, P. Banerjee, Y.Y. Won, A. Akthakul, M.H. Acar, A.M. Mayes,
Macromolecules 35 (2002) 7652–7661;
d) N. Singh, Z. Chen, N. Tomer, S.R. Wickramasinghe, N. Soice, S.M. Husson, J.
(
Membr. Sci. 311 (2008) 225–234.
[
42] A.J. Lovinger, in: D.C. Basset (Ed.), Developments in Crystalline Polymers, 1,
Elsevier Applied Science, London, 1981, p. 195.
[
[
[
43] F.J.C. Braga, S.O. Rogero, A.A. Couto, Mater. Res. 10 (2007) 247–251.
44] D. Wang, K. Li, W.K. Teo, J. Membr. Sci. 163 (1999) 211–220.
45] Y. Liu, J.Y. Lee, E.T. Kang, P. Wang, K.L. Tan, React. Funct. Polym. 47 (2001) 201–
[61] C.M. Crudden, M. Sateesh, R. Lewis, J. Am. Chem. Soc. 127 (2005) 10045–10050.
[62] J.B. Lando, W.W. Doll, J. Macromol Sci. Phys. 2 (1968) 205–218.
[63] M.A. Bachmann, J.B. Lando, Macromolecules 14 (1981) 40–46.
[64] J. Datta, A.K. Nandi, Polymer 38 (1997) 2719–2724.
[65] K. Tashiro, M. Kobayashi, Phase Transitions 18 (1989) 213–246.
[66] M. Kobayashi, K. Tashiro, H. Tadokaro, Macromolecules 8 (1975) 158–171.
[67] M. Bernechea, E. Jesus, C. Lopez-Mardomingo, P. Terreros, Inorg. Chem. 48
(2009) 4491–4496.
[68] Y. Piao, Y. Jang, M. Shokouhimehr, I.S. Lee, T. Hyeon, Small 3 (2007) 255–260.
[69] G. Budroni, A. Corma, H. Garcia, A. Primo, J. Catal. 251 (2007) 345–353.
[70] (a) A. Arcadi, G. Cerichelli, M. Chiarini, M. Correa, D. Zorzan, Eur. J. Org. Chem.
(2003) 4080–4086;
2
13.
46] Y. Chen, D. Liu, Q. Deng, X. He, X. Wang, J. Polym. Sci. Part A: Polym. Chem. 44
2006) 3434–3443.
47] G. Masci, L. Giacomelli, V. Crescenzi, Macromol. Rapid. Commun. 25 (2004)
59–564.
[
[
[
[
(
5
48] S. Samanta, D.P. Chatterjee, S. Manna, A. Mandal, A. Garai, A.K. Nandi,
Macromolecules 42 (2009) 3112–3120.
49] (a) E. Roerdink, G. Challa, Polymer 21 (1980) 509–513;
(
(
b) R.E. Belke, I. Cabasso, Polymer 29 (1988) 1831–1842;
c) D. Dasgupta, S. Manna, A. Garai, A. Dawn, C. Rochas, J.M. Guenet, A.K. Nandi,
(b) R.B. Bedford, M.E. Blake, C.P. Butts, D. Holder, Chem. Commun. (2003) 466–
467.
Macromolecules 41 (2008) 779–787;