Synthesis of multifunctional polymer containing Ni-Pd NPs via thiol-ene reaction for one-pot cascade reactions

Article abstract of DOI:10.1002/aoc.4800

Recently, acid–base bifunctional catalysts have been considered due to their abilities, such as the simultaneous activation of electrophilic and nucleophilic species and their high importance in organic syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid-n-vinylimidazole) containing pentaerythritol tetra-(3-mercaptopropionate) (PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross-linkers were synthesized in the pores of a mesoporous silica structure using click reaction as a novel bifunctional acid–base catalyst. After that, Ni-Pd nanoparticles supported on poly (styrenesulfonic acid-n-vinylimidazole)/KIT-6 as a novel trifunctional heterogeneous acid–base-metal catalyst was prepared. The prepared catalysts were characterized by various techniques like FT-IR, TGA, ICP-AES, DRS-UV, TEM, FE-SEM, EDS-Mapping, and XRD. The synthesized catalysts were efficiently used as bifunctional/trifunctional catalysts for one-pot, deacetalization-Knoevenagel condensation and one-pot, three-step and a sequential reaction containing deacetalization-Knoevenagel condensation-reduction reaction. It is important to note that the synthesized catalyst showing high chemo-selectivity for the reduction of nitro group, alkenyl double bond and ester group in the presence of nitrile. Moreover, it was found that the different nanoparticles including Ni, Pd, and alloyed Ni-Pd showing different chemo-selectivity and catalytic activity in the reaction.

Full text of DOI:10.1002/aoc.4800

Received: 29 October 2018
DOI: 10.1002/aoc.4800
Revised: 13 December 2018
Accepted: 21 December 2018
F U L L P A P E R
Synthesis of multifunctional polymer containing Ni‐Pd NPs
via thiol‐ene reaction for one‐pot cascade reactions
Roozbeh Javad Kalbasi
| Niloofar Mesgarsaravi | Reza Gharibi
Faculty of Chemistry, Kharazmi
University, Tehran, Iran
Recently, acid–base bifunctional catalysts have been considered due to their abil-
ities, such as the simultaneous activation of electrophilic and nucleophilic spe-
cies and their high importance in organic syntheses. However, the synthesis of
acid–base catalysts is problematic due to the neutralization of acidic and basic
groups. This work reports a facial approach to solve this problem via the synthe-
sis of a novel bifunctional polymer using inexpensive materials and easy
methods. In this way, at the first step, heterogeneous poly (styrene sulfonic
acid‐n‐vinylimidazole) containing pentaerythritol tetra‐(3‐mercaptopropionate)
(PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross‐linkers
were synthesized in the pores of a mesoporous silica structure using click reac-
tion as a novel bifunctional acid–base catalyst. After that, Ni‐Pd nanoparticles
supported on poly (styrenesulfonic acid‐n‐vinylimidazole)/KIT‐6 as a novel
trifunctional heterogeneous acid–base‐metal catalyst was prepared. The pre-
pared catalysts were characterized by various techniques like FT‐IR, TGA, ICP‐
AES, DRS‐UV, TEM, FE‐SEM, EDS‐Mapping, and XRD. The synthesized cata-
lysts were efficiently used as bifunctional/trifunctional catalysts for one‐pot,
deacetalization‐Knoevenagel condensation and one‐pot, three‐step and a
sequential reaction containing deacetalization‐Knoevenagel condensation‐
reduction reaction. It is important to note that the synthesized catalyst showing
high chemo‐selectivity for the reduction of nitro group, alkenyl double bond and
ester group in the presence of nitrile. Moreover, it was found that the different
nanoparticles including Ni, Pd, and alloyed Ni‐Pd showing different chemo‐
selectivity and catalytic activity in the reaction.
Correspondence
Roozbeh Javad Kalbasi, Kharazmi
University, Tehran, Iran.
Email: rkalbasi@khu.ac.ir;
rkalbasi@gmail.com
KEYWORDS
Deacetalization‐Knoevenagel condensation, Pd‐Ni alloy nanoparticles, reduction, thiol‐ene click
reaction, tri‐functional catalyst
1 | INTRODUCTION
reaction time and recovery capability. In recent years, cat-
alysts including different active groups (multifunctional)
One‐pot sequential reactions have become an attractive
on their surface are good candidates for improving multi-
ple reactions in a single pot.[4,5] Among the different mul-
tifunctional catalysts that have been presented, most
have focused on acid–base bifunctional catalysts with
some advantages such as decreasing the number of
field due to their high importance in organic syntheses.[1–
3]
The advantages of these reactions include reduce the
number of synthesis steps, simple purifications, high
performance, high atom economy, reduce wastes, decrease
Appl Organometal Chem. 2019;e4800.
wileyonlinelibrary.com/journal/aoc
© 2019 John Wiley & Sons, Ltd.
1 of 20
https://doi.org/10.1002/aoc.4800

2 of 20
JAVAD KALBASI ET AL.
isolation and purification of intermediates. Actually, due
to their ability to simultaneously activate electrophilic
and nucleophilic species, these kinds of catalysts can be
used for one‐pot sequential reactions.[6] This ability can
increase the overall efficiency of the reactions. Therefore,
in the last decades, a large number of bifunctional acid–
base homogenous catalysts have been designed to achieve
this goal. However, due to the lack of recovery ability, con-
tamination of the product with the catalyst, and neutraliza-
tion of the acid and base sites, using bifunctional acid–base
homogeneous catalysts were limited.[7]
In order to improve the properties of bifunctional
homogeneous acid–base catalysts, different research
groups have introduced various bifunctional heteroge-
neous acid–base catalysts and using them in organic
reactions.[8–12] Moreover, in addition to these researches,
a few works have been reported about the synthesis of
heterogeneous trifunctional catalysts containing acidic
and basic sites. One of them and the most important
one is the catalyst that Biradar et al. prepared and used
for one‐pot, three‐step sequential deacetylation‐Henry‐
hydrogenation reaction.[13] This tri‐functional catalyst
included sulfonic acid as an acid group, amine as a basic
group and Pd as a metal nanoparticle, which was sup-
ported on a mesoporous silica. According to these
researches, some of the disadvantages of homogeneous
catalysts were decreased. However, despite many efforts
to the preparation of bifunctional/multifunctional hetero-
geneous acid–base catalysts for one‐pot tandem reactions,
many of the synthesized catalysts (some of them are men-
tioned above) have problems such as the complicated
procedure for preparation of the catalyst. Using
organosilane compounds are not suitable due to toxicity
and high cost and the neutralization of acid–base groups
by each other.
oxygen and 3. the possibility of neutralizing acid and base
monomers with each other. Recently, “click chemistry”
methods offered an excellent opportunity for the prepara-
tion and modification of polymeric materials.[15,16] The
thiol–ene reaction is one of the most important types of
click reactions, which allows simple and efficient synthesis
of different polymeric networks. This reaction includes the
radical addition of thiol functional groups to electron‐rich
enes and producing thioether network.[17,18] High effi-
ciency, uniform distribution of monomers in the polymer
network, oxygen and moisture insensitivity, inoffensive
by‐product, and relatively high reaction rates are some of
the main advantages of thiol‐ene click reaction which are
beneficial for the preparation of polymeric network as the
heterogeneous acid–base catalyst. It is worth to notice that
presence of multifunctional thiol and ene as cross‐linkers
in the final polymeric network led to the spacing between
acid and base groups that could limit the possibility of neu-
tralization of these two groups in the heterogeneous acid–
base catalyst. Therefore, in the present study instead of the
conventional radical polymerization method utilization of
thiol‐ene click chemistry for the preparation of cross‐
linked poly (styrenesulfonic acid‐n‐vinyl imidazole) was
considered. Finally, poly (styrenesulfonic acid‐n‐
vinylimidazole)/KIT‐6 was used as an efficient bifunc-
tional heterogeneous acid–base catalyst for one‐pot tan-
dem deacetalization‐Knoevenagel condensation reaction.
Furthermore, Ni and Pd nanoparticles have been anchored
on poly (styrenesulfonic acid‐n‐vinylimidazole)/KIT‐6 to
prepare a trifunctional heterogeneous acid–base‐metal cat-
alyst. The prepared catalyst was effectively used in the one‐
pot three‐step sequential deacetalization‐Knoevenagel
condensation‐reduction reaction with excellent yields
and interesting selectivity.
In this work, in order to reduce the deficiencies of the
previous synthesized heterogeneous acid–base catalysts,
we report an effective, facile and novel method to synthe-
size a trifunctional heterogeneous acid–base‐metal catalyst
2 | EXPERIMENTAL METHODS
2.1 | Materials and instruments
named
Ni‐Pd@poly
(styrenesulfonic
acid‐n‐
vinylimidazole)/KIT‐6 (Ni‐Pd@poly (SSA‐NVI)/KIT‐6).
In this regard, at the first step, quite heterogeneous poly
All materials were purchased from Aldrich and Merck
in high purity: n‐vinylimidazole (NVI), sodium styrene
sulfonate (SSNa), Amberjet 1200, azobisisobutyronitrile
(AIBN), pentaerythritol tetra‐(3‐mercaptopropionate)
(PETMP), trimethylolpropane trimethacrylate (TMPTMA),
tetraethylorthosilicate (TEOS), n‐butanol, H2O, hydro-
chloric acid (HCl), Pluronic P123 triblock copolymer
(PEG30‐PPG70‐PEG30), NiCl2, PdCl2, sodium borohydride
(NaBH4) and ethanol were used as received without any
further purification.
(styrenesulfonic
acid‐n‐vinylimidazole)
containing
pentaerythritol tetra (3‐mercaptopropionate) (PETMP) as
tetra‐thiol core and trimethylolpropane trimethacrylate
(TMPTMA) species were prepared inside the pores of
KIT‐6 as a mesoporous silica with a high surface area.
Actually, the most common method for the synthesis of
poly (styrenesulfonic acid‐n‐vinyl imidazole) is the con-
ventional radical polymerization method.[14] However,
the mentioned conventional method has some problems
including 1. remaining monomers in the reaction mixture;
2. high sensitivity to radical polymerization relative to
The catalysts were identified using various techniques.
Fourier‐transform infrared spectra (FTIR) were used by
Perkin Elmer RX1 in KBr pellets or neat liquid technology.

JAVAD KALBASI ET AL.
3 of 20
Thermogravimetric (TG) analysis was performed by
Perkin Elmer, Pyris1 under a flow of nitrogen by heating
from room temperature to 700 °C at a rate of 10 °C min
−1. X‐ray powder diffractions (XRD) containing small
and wide angle, were carried out on a Philips PW1730 X‐
ray diffractometer by using Ni‐filtered Cu‐Kα radiation
(λ = 0.15418 nm). Field Emission Scanning Electron
Microscopy (FESEM), energy dispersive spectroscopy
(EDS) and elemental mapping (X‐ray mapping) were car-
ried out for defining the morphology, the elemental analy-
sis and the elemental mapping of the catalysts on a
TESCAN MIRA instrument. Transmission electron micro-
scope (TEM) images were performed on CM30 300 kV.
The pore size distribution and specific surface areas were
studied by Barrett–Joyner–Halenda (BJH) and Brunauer–
Emmett–Teller (BET) methods by using nitrogen
adsorption–desorption measurement at liquid nitrogen
temperature (Series SBELSORP MINI). Diffuse reflectance
spectra (DRS) UV–Vis spectra were recorded by Scinco
4100 apparatus. The Pd and Ni content in samples were
performed by inductively coupled plasma atomic emission
spectrometry (ICP‐AES) by using Perkin‐Elmer optima
2.2.2 | Preparation of poly
(styrenesulfonic acid‐n‐vinylimidazole)/
KIT‐6 nanocomposite (poly (SSA‐NVI)/
KIT‐6)
To synthesize the polymer in the pores of KIT‐6, at first,
0.103 g (0.5 mmol) SSNa was dissolved in 2 ml deionized
water. Then, 0.206 g Amberjet 1200 as an ion exchange
resin was added and stirred for 1 hr. afterward, the mix-
ture was filtered to obtain styrene sulfonic acid (SSA)
monomer. Then, 0.25 g KIT‐6 was added to the remained
solution and stirred. After one hour, 0.904 g (1 mmol)
NVI was added to the mixture and stirred overnight at
room temperature. After an interval time, 0.183 g
(0.37 mmol) PETMP and 0.025 g (0.064 mmol) TMPTMA
and 3 ml ethanol were added to the mixture and it was
mixed for another 15 min. Then, radical polymerization
was started by adding 0.005 g (0.03 mmol) AIBN at
75 °C for 48 hr via thiol‐ene click reaction. Finally, the
obtained product was filtered and washed with deionized
water and dried overnight at room temperature.
1
4300. All the products were performed by HNMR and
2.2.3 | Preparation of Ni‐Pd@poly (styrene
sulfonic acid‐n‐vinylimidazole)/KIT‐6
nanocomposite (Ni‐Pd@poly (SSA‐NVI)/
KIT‐6)
13CNMR spectra of Burker Advanced 300 spectrometer at
300.1 and 75 MHz spectrometers, respectively and GC‐
Mass analysis was carried out by use of Thermoquest–
Finnigan Trace GC–Mass instrument equipped with a
DB‐5 fused silica column (60 m˟0.25 mm i.d., film thick-
ness 0.25 mm) and FT‐IR instrument.
For the preparation of Ni‐Pd@poly (styrene sulfonic
acid‐n‐vinylimidazole)/KIT‐6 nanocomposite, 0.1 mmol
metal chloride containing NiCl2 and PdCl2 mixture with
70:30 molar ratio, respectively, was added to 0.1 g (styrene
sulfonic acid‐n‐vinylimidazole)/KIT‐6 nanocomposite,
together with 3 ml deionized water. For uniform distribu-
tion of metals in the nanocomposite, the mixture was
located in an ultrasonic bath for 15 min. Then, it was
stirred for 4 hrs at 60 °C. After that, a solution of NaBH4
(0.6 mmol NaBH4 with 5 ml deionized water) was added
to the mixture drop by drop under N2 atmosphere and
the mixture was stirred for 4 hr at the same constant tem-
perature. Afterward, the final precipitate was filtered and
washed sequentially with deionized water to remove
excess NaBH4, NiCl2, and PdCl2 and dried at 80 °C for
3 hr. ICP‐AES appraised 0.0476 mmolg−1 Ni and 0.0213
mmolg−1 Pd content of Ni‐Pd@poly (SSA‐NVI)/KIT‐6.
2.2 | Catalysts preparation
2.2.1 | Preparation of KIT‐6
The unique mesoporous silica KIT‐6 was synthesized by
the reported procedure.[19] It was achieved by using
P123 template and TEOS as a structure directing agent
and as the silica precursor, respectively. In a typical syn-
thesis, 6 g (1.03 mmol) P123 was dissolved in 270 g
(15 mol) deionized water and 11.4 g (0.115 mol) HCl solu-
tion (37 wt. %) under stirring. Then, 6 g (0.161 mol) n‐
butanol was added at once with continuous stirring.
Then, after one hour, 12.9 g (0.061 mol) TEOS was added
at once to this mixture and was stirred for 24 hr at 35 °C
in order to form the meso‐structure product. Then, to
expand the silica pore diameters, the obtained sol was
heated for hydrothermal treatment at 93 °C for another
24 hr, statically. The solid product was filtered and
washed by deionized water to remove residue HCl and
dried at 100 °C, overnight. Finally, to remove the organic
template and obtain highly ordered 3D mesoporous KIT‐
6, the product was calcined at 550 °C for 6 hr.
2.3 | General procedure for the one‐pot
sequential deacetalization–Knoevenagel
condensation reaction
In
a
typical reaction procedure, benzaldehyde
dimethylacetal (1 mmol), ethyl cyanoacetate (1 mmol)
and poly (SSA‐NVI)/KIT‐6 (0.03 g) were added to 3 ml

4 of 20
JAVAD KALBASI ET AL.
deionized water in a round‐bottomed flask. The resulting
mixture was stirred at 45 °C for 30 min. Thin layer chro-
matography (hexane‐ethyl acetate with 4:1 ratio) was
used to follow the progress of the reaction. After the com-
pletion of the reaction, the mixture was cooled down to
10 °C, filtered and the remaining solid was washed by
hot ethanol (10 ml). Afterward, the precipitate appeared
in the solution. After crystallization, the final product
was isolated to achieve a pure product. Resulting product
2.3.4 | Ethyl (E)‐3‐(4‐chlorophenyl)‐2‐
cyanoacrylate
FT‐IR (KBr, cm−1
)
3036 (=CH, Ar, str.), 2990 (CH, str.), 2223 (CN),
1723(C=O), 1612–1491 (Ar, str.), 832(C‐Cl); 1H NMR
(300 MHz, CDCl3,Hz) δ ppm: 8.20 (=CH, s, 1H), 7.95
(ArH, d, 2H, J = 8.7), 7.49 (ArH, d, 2H, J = 8.7), 4.40
(CH2‐O, q, 2H, J = 7.2), 1.42(CH3, t, 3H, J = 7.2);
13CNMR (75 MHz, CDCl3) δ ppm: 162.2 (C=O), 153.4
(C‐Ar), 132.2(C‐Cl), 131.36, 129.8, 129.6, 115.2(CN),
103.5(C‐CN), 62.8 (C‐O), 14.1.
1
obtained in 93% yield and was identified by H‐NMR,
13C‐NMR, and FT‐IR spectroscopies.
2.3.1 | Ethyl (E)‐2‐cyano‐3‐(2‐nitrophenyl)
2.3.5 | Ethyl (E)‐2‐cyano‐3‐(2,
6‐dichlorophenyl) acrylate
acrylate
FT‐IR (KBr, cm−1
)
FT‐IR (KBr, cm−1
)
3071–3032 (=CH, Ar, str.), 2987 (CH, str.), 2226 (CN),
1718 (C=O), 1606–1472 (C=C alkene, C=C aromatic),
3075, 3036 (=CH, Ar, str.), 2981 (CH, str.), 2236 (CN),
1722(C=O), 1555–1476 (Ar, str.), 797(C‐Cl); 1H NMR
(300 MHz, CDCl3,Hz) δ ppm: 8.29 (=CH, s, 1H), 7.31–
7.44 (ArH, m, 3H), 4.42 (CH2‐O, q, 2H, J = 7.2),
1.43(CH3, t, 3H, J = 7.2); 13CNMR (75 MHz, CDCl3) δ
ppm: 160.6 (C=O), 151.1 (C‐Ar), 134.1, 131.6, 130.3,
128.5, 113.9 (CN), 113.3(C‐CN), 63.1(C‐O), 14.0.
1
1529–1355 (N=O); H NMR (300 MHz, CDCl3,Hz) δ
ppm: 8.70 (=CH, s, 1H), 8.39–8.44 (ArH, m, 2H), 8.31
(ArH, s, 1H), 7.74 (ArH, t, 1H, J = 8.1), 4.43 (CH2‐O, q,
2H, J = 7.2), 1.42(CH3, t, 3H, J = 7.2);); 13CNMR
(75 MHz, CDCl3) δ ppm: 167.4 (C=O), 151.8, 145.4,
135.1, 132.8, 130.5, 127.0, 125.8, 114.5 (CN), 106.6 (C‐
CN), 63.1 (C‐O), 14.1.
2.3.6 | Ethyl (E)‐2‐cyano‐3‐(4‐
methoxyphenyl) acrylate
2.3.2 | Ethyl (E) ‐ 2‐cyano‐3‐ (p‐tolyl)
acrylate
FT‐IR (KBr, cm−1
)
3028 (=CH, Ar, str.), 2991 (CH, str.), 2215 (CN), 1718
(C=O), 1585–1475 (C=C alkene, C=C aromatic); 1H
NMR (300 MHz, CDCl3,Hz) δ ppm: 8.17 (=CH, s, 1H),
8.1 (ArH, d, 2H, J = 9), 7.00 (ArH, d, 2H, J = 9), 4.37
(CH2‐O, q, 2H, J = 7.2), 3.90(CH3‐O,S, 3H) 1.39 (CH3, t,
3H, J = 7.2); 13CNMR (75 MHz, CDCl3) δ ppm: 163.7
(C=O), 163.1, 154.3 (C‐Ar), 133.6, 124.3, 116.2(CN),
114.7, 99.3 (C‐CN), 62.4 (C‐O), 55.5 (CH3O), 14.1.
FT‐IR (KBr, cm−1
)
3028 (=CH, Ar, str.), 2985 (CH, str.), 2217 (CN),
1722(C=O), 1597–1462 (C=C alkene, C=C aromatic);
1H NMR (300 MHz, CDCl3, Hz) δ ppm: 8.22 (=CH, s,
1H), 7.92–7.89 (ArH, d, 2H, J = 8.7), 7.32–7.26 (ArH, d,
2H, J = 8.7), 4.42–4.35 (CH2‐O, q, 2H, J = 7.2), 2.44
(CH3‐Ar, s, 3H), 1.42(CH3, t, 3H, J = 7.2); 13CNMR
(75 MHz, CDCl3) δ ppm: 162.8 (C=O), 155.0 (C‐Ar),
144.6, 131.2, 130.0, 128.8, 115.8(CN), 62.6(C‐O),
21.9(CH3‐Ar), 14.1.
2.4 | General procedure for the one‐pot
sequential deacetalization‐Knoevenagel
condensation‐reduction reaction
2.3.3 | Ethyl (E)‐2‐cyano‐3‐(thiophen‐2‐yl)
The reaction mixture composed of benzaldehyde
dimethylacetal (1 mmol), ethyl cyanoacetate (1 mmol),
Ni‐Pd@poly (SSA‐NVI)/KIT‐6 (0.03 g) and deionized
water (3 ml) was added in a glass reactor. The resulting
mixture was stirred at 45 °C for 30 min. Thin layer chro-
matography (hexane‐ethyl acetate with 4:1 ratio) was
used to follow the progress of the reaction. After the com-
pletion of the deacetalization‐Knoevenagel condensation
reaction, 1 mmol NaBH4 was added to the reaction mix-
ture and the resulting mixture was stirred at 45 °C for
20 min. Thin layer chromatography (hexane‐ethyl acetate
acrylate
FT‐IR (KBr, cm−1
)
3086, 3027 (=CH, Ar, str.), 2975 (CH, str.), 2218 (CN),
1
1715(C=O), 1597–1464 (Ar, str.); H NMR (300 MHz,
CDCl3,Hz) δ ppm: 8.35 (=CH, s, 1H), 7.84 (ThiO‐H, d,
1H, J = 3.9), 7.79 (ThiO‐H, d, 1H, J = 5.1), 7.23 (ThiO‐
H, dd, 1H, 3 J = 5.1, 4 J = 3.9), 4.37 (CH2‐O,, q, 2H,
J = 7.2), 1.39(CH3, t, 3H, J = 7.2); 13CNMR (75 MHz,
CDCl3) δ ppm: 162.6 (C=O), 146.6, 137.1, 136.0, 135.1,
128.6, 115.7(CN), 99.3(C‐CN), 62.5 (C‐O), 14.1.

JAVAD KALBASI ET AL.
5 of 20
with 3:2 ratio) was used to follow the progress of the reac-
tion. After the completion of the reaction, the mixture
was cooled to room temperature. Then, the product of
reduction (organic phase) was extracted with chloroform
(2 × 10 ml) and the organic phase was dried over anhy-
drous Na2SO4. The suspension was filtered and the sol-
vent was evaporated under vacuum to give the desired
product. To achieve pure product, TLC on 60 F254 silica
gel plates was used. The final product was characterized
Hz) δ ppm: 7.19–7.26 (ArH, m, 2H), 6.99–7.06 (ArH, m,
2H), 3.70–3.81 (CH2‐O, m, 2H), 2.87–2.97 (CH‐CN, CH2‐
Ar, m, 3H), 2.36(OH, s, 1H); 13CNMR (75 MHz, CDCl3)
δ ppm: 163.69, 160.4(C‐F), 132.0, 132.0, 130.6, 130.5,
120.2 (CN), 115.8, 115.54, 61.6 (C‐O), 36.8 (C‐Ar), 33.6
(C‐CN).
3 | RESULTS AND DISCUSSION
1
by FT‐IR, HNMR, 13CNMR and GC‐Mass techniques.
This product was obtained in 94% yield.
As explained in the experimental section, poly (SSA‐
NVI)/KIT‐6 was synthesized via the in situ polymeriza-
tion of styrene sulfonic acid and n‐vinyl imidazole in
the presence of PETMP as tetra‐thiol core and TMPTMA
through a click type reaction in the pores of KIT‐6 meso-
porous silica material. Also, Ni‐Pd@poly (SSA‐NVI)/KIT‐
6 was fabricated through the anchoring of Ni‐Pd alloy
nanoparticles on poly (SSA‐NVI)/KIT‐6. Figure 1 shows
a schematic description of the steps for the preparation
of Ni‐Pd@poly (SSA‐NVI)/KIT‐6.
2.4.1 | 2‐(3‐aminobenzyl)‐3‐
hydroxypropanenitrile
FT‐IR (KBr, cm−1
)
3358(NH2), 3043 (=CH, Ar, str.), 2993 (CH, str.), 2242
1
(CN), 1606–1463 (Ar, str.); H NMR (300 MHz, CDCl3,
Hz) δ ppm: 7.08–7.17 (ArH, m, 1H), 6.57–6.75 (ArH, m,
3H), 3.67–3.76 (CH2, m, 2H), 2.85–4.24 (OH, NH2, br,
3H), 2.85–2.95 (CH2, CH, m, 3H); 13CNMR (75 MHz,
CDCl3) δ ppm:146.6 (C), 137.5 (C), 129.7 (C), 119.1
(CN), 117.1, 115.5, 114.0 (CH), 61,7 (CH2‐OH), 36.5
(CH2), 34.4 (CH‐CN); LRMS m/z (Abund %) 176 [M
+.] (31.9), 128 (6.3), 107 [106‐H+.] (100), 106 [NH2‐Ph‐
CH2+.] (76), 93 (5.1), 77 (15.4).
3.1 | Characterization of the catalysts
The FT‐IR spectra of PETMP (tetra thiol core) and
TMPTMA species and cross‐linked poly (SSA‐NVI) are
presented in Figure 2. For PETMP, the peak at 2959 cm
−1
is assigned to the aliphatic C‐H stretching vibration
2.4.2 | 3‐hydroxy‐2‐(4‐methoxybenzyl)
propanenitrile
and the peaks at 2567 cm−1 and 1735 cm−1 are related
to the S‐H and C=O stretching vibration of PETMP.[19]
FT‐IR (KBr, cm−1
)
For TMPTMA, the peaks at 3104 cm−1, 2961 cm−1
,
3459(OH), 3032 (=CH, Ar, str.), 2927 (CH, str.), 2242
1735 cm−1, and 1639 cm−1 are related to alkene C‐H
stretching vibration, aliphatic C‐H stretching vibration,
C=O stretching vibration and olefinic C=C stretching
vibration, respectively.[20]
1
(CN), 1513–1612 (Ar, str.), H NMR (300 MHz, CDCl3,
Hz) δ ppm: 7.16 (ArH, d, 2H, J = 8 Hz), 6.86 (ArH, d,
2H, J = 8 Hz), 3.78 (OMe, s, 3H), 3.67–3.74 (CH2‐O, m,
2H), 2.9 (CH‐CN, CH2‐Ar, m, 3H), 2.61(OH, s, 1H).
For the cross‐linked poly (SSA‐NVI), the shown peak
at 3434 cm−1, 1356 cm−1, and 1189 cm−1 are attributed to
the hydroxyl group of SO3H and asymmetric as well as
symmetric stretching vibration of S=O group, respec-
tively, which are related to the poly (styrenesulfonic
acid).[21] Also, the peak at 1468 cm−1 is related to the
C=N bond of poly n‐vinylimidazole. Moreover, the peaks
at 3116 cm−1 and 2969 cm−1 are indicated the stretching
vibration of aromatic and aliphatic C‐H, respectively,
which are related to cross‐linked poly (SSA‐NVI).[22]
Actually, the absence of the peaks at 2567 cm−1 (S‐H)
and 1650 cm−1 (C=C) and the existence of the peak at
1735 cm−1 (C=O) in FT‐IR spectrum of cross‐linked poly
(SSA‐NVI) indicate that PETMP and TMPTMA are
successfully entered into the poly (SSA‐NVI) structure.
Finally, these evidence show the successful formation of
cross‐linked poly (SSA‐NVI) through thiol‐ene click
reaction.
2.4.3 | 2‐benzyl‐3‐hydroxypropanenitrile
FT‐IR (KBr, cm−1
)
3430(OH), 3030 (=CH, Ar, str.), 2934 (CH, str.), 2245 (CN),
1
1497–1603 (Ar, str.); H NMR (300 MHz, CDCl3,Hz) δ
ppm: 7.25–7.37 (ArH, m, 5H), 3.73–3.83 (CH2‐OH, m,
2H), 2.9–3.1 (CH‐CN, CH2‐Ar, m, 3H), 2.16 (OH, s, 1H);
13CNMR (75 MHz, CDCl3) δ ppm: 136.3, 128.9, 128.8,
127.3, 120.3 (CN), 61.7 (C‐O), 36.7 (C‐Ph), 34.4 (C‐CN).
2.4.4 | 2‐(4‐fluorobenzyl)‐3‐
hydroxypropanenitrile
FT‐IR (KBr, cm−1
)
3441(OH), 3042 (=CH, Ar, str.), 2927 (CH, str.), 2244
1
(CN), 1511–1601 (Ar, str.); H NMR (300 MHz, CDCl3,

6 of 20
JAVAD KALBASI ET AL.
FIGURE 1 Synthesis of Ni‐Pd@poly (SSA‐NVI)/KIT‐6
Furthermore, FT‐IR spectra of pure KIT‐6 and poly
(SSA‐NVI)/KIT‐6 nanocomposite are shown in Figure 2.
The FT‐IR spectrum of pure KIT‐6 shows two bands at
3459 cm−1 and 1635 cm−1 which are related to the
stretching and bending vibration of the adsorbed water
molecules on the surface and OH of internal silanol
groups of KIT‐6. Also, the very strong and broad peak at
1082 cm−1 and the peak at 803 cm−1 are attributed to
the asymmetric and symmetric stretching vibrations,
respectively and the peak at 461 cm−1 is assigned to the
bending vibration of Si‐O‐Si bonds of KIT‐6.[23]
As shown in poly (SSA‐NVI)/KIT‐6 nanocomposite
spectrum, all the peaks of the KIT‐6 are displayed which
indicate the presence of KIT‐6 in the nanocomposite
structure. Also, all of the poly (SSA‐NVI) peaks which
described in Figure 2 are observed in the nanocomposite
spectrum, that proves the successful synthesis of the
desired nanocomposite (poly (SSA‐NVI)/KIT‐6).
The low‐angle XRD patterns of poly (SSA‐NVI)/KIT‐6
and Ni‐Pd@poly (SSA‐NVI)/KIT‐6 are displayed in
Figure 3a. For both of poly (SSA‐NVI)/KIT‐6 and Ni‐
Pd@poly (SSA‐NVI)/KIT‐6, the small peaks at 1.44°, 2°,
and 2.26 ° are attributed to (211),) 220) and (320) diffrac-
tion planes of ordered three‐dimensional cubic Ia3d sym-
metry of KIT‐6, which exists in the structure of these
composites.[24] It is important to note that the above‐
mentioned peaks in these composites are broader than
the pure KIT‐6, which is due to the sectional blocking
of mesoporous KIT‐6 by poly (SSA‐NVI) and also the dis-
tribution of Pd and Ni nanoparticles in their structures.
Figure 3b shows the wide‐angle XRD patterns of the
Ni@poly (SSA‐NVI)/KIT‐6, Pd@poly (SSA‐NVI)‐KIT‐6
and Ni‐Pd@poly (SSA‐NVI)/KIT‐6 nanocomposites. For
all samples, a broad peak at 2θ = 20–30 is related to the
amorphous silica structure of mesoporous KIT‐6. The
XRD of Pd@poly (SSA‐NVI)/KIT‐6 exhibits the peaks at
39.8°, 46.85°, and 68.2°, which indicate the (111), (200)
and (220) lattice planes of fcc crystalline structure of
metallic Pd.[25] Also, any clear peaks were observed for
Ni@poly (SSA‐NVI)/KIT‐6, which could be due to the
amorphous nature and small size of Ni nanoparticles.[26]
Furthermore, the XRD of Ni‐Pd@poly (SSA‐NVI)/KIT‐6
shows (111) diffraction peak of Pd at 40.05°. This peak
was appeared in low intensity at higher 2θ compared with
Pd@poly (SSA‐NVI)/KIT‐6, which indicates the forma-
tion of alloy between Ni and Pd in the Ni‐Pd@poly
(SSA‐NVI)/KIT‐6.[27]
Figure 4 displays the N2 adsorption–desorption iso-
therms and BJH pore size distributions of poly (SSA‐
NVI)/KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6. The N2
adsorption–desorption isotherm of poly (SSA‐NVI)/
KIT‐6 shows type IV isotherm with hysteresis loop in

JAVAD KALBASI ET AL.
7 of 20
FIGURE 2 FT‐IR spectra of TMPTMA, PETMP, poly (SSA‐NVI), KIT‐6 and poly (SSA‐NVI)/KIT‐6
FIGURE 3 (a) Low‐angle XRD patterns of Poly (SSA‐NVI)/KIT‐6 and Ni‐Pd@Poly (SSA‐NVI)/KIT‐6; (b) Wide‐angle XRD patterns of
Pd@poly (SSA‐NVI)/KIT‐6, Ni@poly (SSA‐NVI)/KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6
the p/p0 at 0.4–1.0, which indicates the mesoporous
structure of this sample.[28] Also, the N2 adsorption–
desorption isotherm of Ni‐Pd@poly (SSA‐NVI)/KIT‐6 dis-
plays type IV isotherm with hysteresis loop in the p/p0 at
0.4–1.0 like poly (SSA‐NVI)/KIT‐6. This result confirms
that the mesoporous structure of poly (SSA‐NVI)/KIT‐6
is preserved in Ni‐Pd@poly (SSA‐NVI)/KIT‐6 after the
incorporation of metal nanoparticles. Furthermore, some
physical properties such as surface area, pore volume,
and pore diameter of these samples are listed in Table 1.
The surface area and pore volume of poly (SSA‐NVI)/
KIT‐6 are 258 m2 g−1 and 0.56 cm3 −1, respectively.
g
However, both of these parameters were decreased to
174 m2 g−1 and 0.45 cm3 g−1 in Ni‐Pd@poly (SSA‐NVI)/
KIT‐6, that these results suggest the incorporation
of Ni and Pd nanoparticles in the pores of poly

8 of 20
JAVAD KALBASI ET AL.
FIGURE 4 N2 adsorption–desorption isotherms of poly (SSA‐NVI)/KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6. Inside: BJH pore sizes of poly
(SSA‐NVI)/KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6
TABLE 1 Physicochemical parameters of poly (SSA‐NVI)/KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6 obtained from N2 adsorption–
desorption analysis
Smesoporea
Vmesoporea
Dmesoporeb
[nm]
Smicroporec
Vmicroporec
[cm3 g−1
]
Dmicroporec
[nm]
Sample
[m2 g−1
]
[cm3 g‐ 1
]
[m2 g−1
]
poly (SSA‐NVI)/KIT‐6
258
174
0.56
0.45
7
8
350
266
0.1
1.8
1.8
Ni‐Pd@ poly (SSA‐NVI)/KIT‐6
0.08
aCalculated by BET method.
bMean pore diameter determined using BJH method.
cCalculated by MP‐Plot method.
(SSA‐NVI)/KIT‐6.[29–31] From Table 1, the pore diameter
of poly (SSA‐NVI)/KIT‐6 is 7 nm. However, after the
incorporation of metal nanoparticles, it is enhanced to
8 nm in Ni‐Pd@poly (SSA‐NVI)/KIT‐6, which it can be
related to the physical pressure of these nanoparticles
from inside to the wall of the pores.[32,33] In addition,
the MP‐plot and t‐plot confirm the existence of micro-
pores beside of the mesopores for both poly (SSA‐NVI)/
KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6 (Table 1), and
also the diameters of micropores are equal for these sam-
ples, which shows that the Ni‐Pd nanoparticles are just
placed into the mesopores. Finally, based on the above‐
mentioned results, it was found that poly (SSA‐NVI)/
KIT‐6 and Ni‐Pd@poly (SSA‐NVI)/KIT‐6 have the meso‐
micro hierarchical porous structures.
of Ni‐Pd@poly (SSA‐NVI)/KIT‐6 display the same struc-
ture of support, but the surface seems a little rough,
which it could be related to the incorporation of Ni and
Pd nanoparticles (Figure 5b and c).
Furthermore, the EDS analysis and FE‐SEM‐
elemental mapping of poly (SSA‐NVI)/KIT‐6 show the
presence of N, S, C, Si and O on the selected area of the
surface, which confirm the successful formation of poly
(SSA‐NVI) on the surface of KIT‐6 (Figure 6a and b).
The EDS analysis and FE‐SEM‐elemental mapping of
Ni‐Pd@poly (SSA‐NVI)/KIT‐6 show the presence of Ni
and Pd in addition to N, S, C, Si and O (Figure 7a and
b). Also based on the images of elemental mapping anal-
ysis, it was found that Ni and Pd have a uniform distribu-
tion on the selected area of the surface. According to the
EDS results, the atomic molar ratio of Ni:Pd was calcu-
lated 1.31, while it was determined 2.23 based on the
ICP‐AES. This difference indicates that the main amount
of Pd nanoparticles are on the outer surface of Ni‐
The FE‐SEM images of poly (SSA‐NVI)/KIT‐6 and
Ni‐Pd@poly (SSA‐NVI)/KIT‐6 are displayed in Figure 5.
The FE‐SEM image of poly (SSA‐NVI)/KIT‐6 shows the
rock‐like structure of KIT‐6[34] (Figure 5a). The images

JAVAD KALBASI ET AL.
9 of 20
FIGURE 5 (a) FESEM image of poly (SSA‐NVI)/KIT‐6 and (b, c) FESEM images of Ni‐Pd@poly (SSA‐NVI)/KIT‐6
Pd@poly (SSA‐NVI)/KIT‐6. Also, it should be noted that
EDS is a qualitative analysis and ICP‐AES is a technique
to determine the exact amount of nanoparticles.
The thermal stability of samples was determined by
thermogravimetric analysis. The thermal degradation
study of samples was done in an N2 environment at a
heating rate of 10 °C/min. The corresponding TGA and
DTGA thermograms of poly (SSA‐NVI)/KIT‐6 and Ni‐
Pd@poly (SSA‐NVI)/KIT‐6 are collected in Figure 10a
and b, respectively. For both samples, the observed
weight loss below 100 °C is related to the loss of physi-
cally adsorbed water. Both samples showed a two‐step
degradation profile. The first transition started at about
290 °C was related to the thermal dissociation of steric
groups of PETMP and TMPTMA as cross‐linkers and sul-
fonic acid groups of polymer networks. The second main
thermal degradation event at a 462 °C (19% w/w) for poly
(SSA‐NVI)/KIT‐6 and 365 °C (12% w/w) for Ni‐Pd@poly
(SSA‐NVI)/KIT‐6 was attributed to the scission of ali-
phatic and aromatic segments of polymeric networks.
It is important to note that the second weight loss of
Ni‐Pd@poly (SSA‐NVI)/KIT‐6 was happened at a lower
temperature compared to poly (SSA‐NVI)/KIT‐6, which
could be related to the catalytic effect and thermal con-
ductivity of Ni‐Pd nanoparticles. Based on these results,
it was understood that both of poly (SSA‐NVI)/KIT‐6
and Ni‐Pd/poly (SSA‐NVI)/KIT‐6 are thermally stable
below 290 °C.
TEM images of Ni‐Pd@poly (SSA‐NVI)/KIT‐6 are
shown in Figure 8. These images show a highly ordered
cubic Ia3d pore channels, which exist in the structure of
Ni‐Pd@poly (SSA‐NVI)/KIT‐6 and are belonged to the
KIT‐6 structure. The dark parts in the images are
assigned to Pd and Ni nanoparticles, which distributed
on the surface and into the channels of the nanocompos-
ite.[35,36] It is important to note that the regular and uni-
form structure of KIT‐6 remained without any changing
after polymerization and incorporation of metal nanopar-
ticles. This result is confirmed by the SEM‐EDS, XRD,
and N2 adsorption–desorption.
Figure 9 shows DRS UV–Vis spectra of poly (SSA‐
NVI)/KIT‐6, Ni+2‐Pd+2@poly (SSA‐NVI)/KIT‐6 and Ni‐
Pd@poly (SSA‐NVI)/KIT‐6 samples. For Ni+2‐Pd+2@poly
(SSA‐NVI)/KIT‐6, the peaks at 265, 314 and 370 nm are
assigned to Pd+2 and the peaks at 361 and 580 nm are
related to Ni2+.[37,38] For Ni‐Pd@poly (SSA‐NVI)/KIT‐6,
the intensity of the above‐mentioned peaks is decreased,
and also the peak of Ni2+ at 580 nm disappeared, which
indicate to the reduction of Ni+2 and Pd+2 to Ni and Pd
nanoparticles.

10 of 20
JAVAD KALBASI ET AL.
FIGURE 6 (a) EDS analysis and (b) FESEM‐elemental‐mapping images of poly (SSA‐NVI)/KIT‐6
styrenesulfonic acid to n‐vinyl imidazole (entry 2), has
the best yield at the lowest reaction time. Also, in order
to investigate the effect of the amount of KIT‐6 silica sup-
port on the reaction process, different values of KIT‐6
(0.25, 0.5 and 1 g) were used to prepare the nanocompos-
ite while the monomeric molar ratio was fixed at 2:1
(Table 2, entries 2–4). Actually, the role of KIT‐6 is acting
as a mesoporous support to well distributing of polymer
chains and increasing the surface area of the catalyst as
well as heterogeneity. According to the results presented
in Table 2, with increasing the amount of KIT‐6, the yield
of the reaction decreases. Actually, in the one hand,
increasing the amount of KIT‐6 more than 0.25 g cause
to an excessive increase in the surface area of the catalyst.
On the other hand, it leads to reduce the amount of poly-
mer and subsequently, reduce the amount of active acidic
and basic groups at the surface of the nanocomposite.
Therefore, it ultimately reduces the catalytic activity.
Thus, the catalyst containing the amount of 0.25 g of
KIT‐6 was selected as an optimum nanocomposite.
3.2 | Catalytic activity
In this study, poly (SSA‐NVI)/KIT‐6 and Ni‐Pd@poly
(SSA‐NVI)/KIT‐6 nanocomposites were synthesized as
novel polymeric heterogeneous catalysts, and they were
characterized by various techniques.
Poly (SSA‐NVI)/KIT‐6 was used as an acid–base
bifunctional catalyst to perform a sequential one‐pot
deacetalization–Knoevenagel condensation reaction at
45 °C in the presence of water as solvent, which the acidic
groups catalyze the first step (hydrolysis of benzaldehyde
dimethyl acetal) and the basic groups catalyze the second
step (Knoevenagel condensation) (Scheme 1).
Due to the presence of acidic and basic groups in the
polymer network, the amount of polymer which was used
for the preparation of the catalyst plays a significant role.
Regarding this point, the desired reactions were studied
in the presence of different monomeric ratios used for
the preparation of the catalyst, while the amount of
KIT‐6 was fixed (0.25 g) (Table 2, entries 1,2,5). According
to the results presented in Table 2, it can be found that
the catalyst prepared by 2:1 monomer molar ratio of
Moreover, in order to find a good reason for the effect
of monomer molar ratio on the catalytic activity of poly

JAVAD KALBASI ET AL.
11 of 20
FIGURE 7 (a) EDS analysis and (b) FESEM‐elemental‐mapping images of Ni‐Pd@ Poly (SSA‐NVI)/KIT‐6
(SSA‐NVI)/KIT‐6, the amount of acidic and basic sites of
the catalysts prepared by various amount of monomer
molar ratio were measured by a back titration method
which, the results are shown in Table 3 and 4. To
measure, poly (SSA‐NVI)/KIT‐6 composite (0.1 g) was
added to a test tube, and 15 ml H2O with HCl 0.1 M
(or 0.1 M NaOH) solution were added. The mixture
was stirred for an hour at ambient temperature, then
the mixture was filtered and rinsed with 5 ml deionized
water. The resulting filtrate was titrated with 0.1 M
NaOH (or 0.1 M HCl) solution by using phenolphthalein
as an indicator. According to the Table 3, it is observed
that the catalyst with 2:1 molar ratio of SSA:NVI
(styrenesulfonic acid to n‐vinyl imidazole) give a loading
of 0.82 mmol g−1 (theoretical value, 0.88 mmol g−1) of
sulfonic acid groups (Table 3, entry 2) and
0.132 mmol g−1 (theoretical value, 0.177 mmol g−1) of
amine groups (Table 4, entry 2). Therefore, the percent-
age of available (free) amine is 74% and the free acid per-
centage is 93%. By comparing this catalyst with other
catalysts prepared with different molar ratios, it is found
that the catalyst prepared with 2:1 molar ratio of SSA:
NVI has the highest amount of free acid and base sites,
together (Table 3 and Table 4). This represents the
better catalytic feature of the catalyst prepared by 2:1
monomer molar ratio, so this ratio can be chosen as an
optimum amount.
Furthermore, to investigate the role of cross‐linkers, a
similar catalyst was prepared without using cross‐linkers
and it was compared with the catalyst prepared with
cross‐linkers. First of all, it was revealed that the polymer
prepared without cross‐linkers has the potential for solu-
bility in ethanol and water (the catalyst was not heteroge-
neous), but with the using of cross‐linkers in the polymer
network, the polymer doesn't dissolve in as mentioned
solvents and the catalyst was completely heterogeneous.
Secondly, the results showed that the presence of cross‐
linkers have increased the yield of polymerization,
distinctly (Table S1). Finally, the catalytic activity of these
catalysts was compared for one‐pot deacetalization–
Knoevenagel condensation reaction and the results
showed the superior activity of the catalyst which was
prepared using cross‐linkers (Table S2).
These results show that using the thiol‐ene method
and PETMP and TMPTMA as cross‐linkers which can
act as a spacer between acid and base group, most of
the acidic and basic sites of the catalyst are free and
neutralization of these two groups is minimized.
Another factor that plays an important role in the
reaction process is the amount of consumable catalyst
that contains acid and base active sites.
According to Table 5, when the catalyst value is less
than 0.03 g, the yield of the reaction is not acceptable
(entry 1). Also, when the amount of catalyst increases to

12 of 20
JAVAD KALBASI ET AL.
FIGURE 8 TEM images of Ni‐Pd@poly (SSA‐NVI)/KIT‐6
more than 0.03 g, there is no significant effect on the yield
of the reaction. Therefore, considering the economic
aspects, the amount of 0.03 g of catalyst is selected as
an optimum amount.
The optimum conditions for this reaction were
selected based on deacetalization–Knoevenagel conden-
sation reaction and for the reduction step, sodium
borohydride was selected as a reducing agent. The results
for sequential one‐pot deacetalization–Knoevenagel
condensation‐reduction reaction between different benz-
aldehyde dimethyl acetals and ethylcyanoacetate are
presented in Table 7. According to the results, all the
reactions were completed in considerable times and
afforded the desired products in high yields. Moreover,
looking the results, it can be found that in the reduction
step, alkene and ester groups will reduce to alkane and
alcohol, respectively, whilst, the nitrile group remained
unreacted (Table 7, entries 1–8). It should be mentioned
that even with increasing the amount of NaBH4, it
remained unreacted. It means that the catalyst can be
used as a chemo‐selective heterogeneous catalyst.
Finally, under the optimal conditions, benzaldehyde
dimethyl acetals derivatives with various substitution
groups and active methylene compounds (ethylcyanoacetate
and malononitrile) were reacted (Table 6). It is seen that
all the reactions are performed with high yields and
relatively low reaction times. Furthermore, the reactions
which were performed with the malononitrile as an
active methylene compound show less reaction time and
more yields than that of ethylcyanoacetate (Table 6,
entries 19–25).
In the next step, Ni‐Pd@poly (SSA‐NVI)/KIT‐6 nano-
composite was used as a promoter in the sequential one‐
pot deacetalization–Knoevenagel condensation‐reduction
reaction in water at 45 °C. In this reaction, the
deacetalization step is performed by the acid groups of
the catalyst, then Knoevenagel condensation is carried
out by the basic groups of the catalyst, and finally, the
metals catalyze the reduction step (Scheme 2).
Also, the sequential one‐pot three‐step reaction of 3‐
nitro benzaldehyde dimethylacetal and ethylcyanoacetate
was specifically studied (Table 7, entry 9). As can be seen,
in the reduction step over Ni‐Pd@poly (SSA‐NVI)/KIT‐6
catalyst, alkene (C=C), ester (CO2Et) and nitro (NO2)

JAVAD KALBASI ET AL.
13 of 20
FIGURE 9 DRS UV–vis spectra of Ni‐Pd@poly (SSA‐NVI)/KIT‐6, Ni2+‐Pd2+@poly (SSA‐NVI)/KIT‐6 and poly (SSA‐NVI)/KIT‐6 samples
FIGURE 10 (a) TGA and (b) DTG curves of the poly (SSA‐NVI)/KIT‐6 and Ni‐Pd@poly (SSA‐NVI) KIT‐6
(Scheme 3, product 2) had the same results with Ni‐Pd@-
poly (SSA‐NVI)/KIT‐6. On the other hand, surprisingly, it
was found that when nickel nanoparticle containing cat-
SCHEME
condensation reaction
1
Sequential
deacetalization‐Knoevenagel
alyst was used alone, the catalyst (Ni@poly (SSA‐NVI)/
KIT‐6) even with high amounts of NaBH4 was only able
to reduce the ester and alkene groups (product 1) in a
reasonable yield. These results were confirmed by the
groups were completely reduced to alkane, alcohol, and
amine in excellent yield (Scheme 3, product 2). However,
nitrile group was still unreacted.
To achieve more useful results about the role of
metals, the same reaction was repeated over Pd@poly
(SSA‐NVI)/KIT‐6 and Ni@poly (SSA‐NVI)/KIT‐6 cata-
lysts (Scheme 3). The results showed that the reaction
which was performed over Pd@poly (SSA‐NVI)/KIT‐6
1
GC‐Mass, H NMR, 13C NMR and FT‐IR of the crude
products. These results prove the chemo‐selectivity of
the catalysts prepared with different metals.
As we found that the metal nanoparticles show
different catalytic activity and chemo‐selectivity for
the sequential one‐pot deacetalization–Knoevenagel
condensation‐reduction reaction between
3‐nitro

14 of 20
JAVAD KALBASI ET AL.
TABLE 2 Effect of monomer molar ratio and KIT‐6 amount on
catalytic activity of poly (SSA‐NVI)/KIT‐6 for one‐pot
deacetalization–Knoevenagel condensation reactiona
TABLE 5 Effect of amount of poly (SSA‐NVI)/KIT‐6 on sequen-
tial one‐pot reaction of deacetalization–Knoevenagel condensationa
Entry
Amount of catalyst (g)
Yield [%]b
Monomer molar ratio
(SSA:NVI)
Amount of KIT‐
6 (g)
Yield
[%]b
1
2
3
0.01
0.03
0.05
86
94
95
Entry
1
2
3
4
5
1:1
2:1
2:1
2:1
3:1
0.25
0.25
0.5
71
94
81
50
85
aReaction condition: 3‐nitro benzaldehyde dimethyl acetal (1 mmol),
ethylcyanoacetate (1 mmol) and H2O (3 ml) at 45 °C, reaction time: 30 min.
bIsolated yields.
1
0.25
aReaction condition: 3‐nitro benzaldehyde dimethyl acetal (1 mmol),
ethylcyanoacetate (1 mmol), catalyst (0.03 g) and H2O (3 mL), 45 °C, reaction
time: 30 min.
preparation of the catalyst, the catalyst prepared by Ni:
Pd (70:30 molar ratio) was chosen as the best catalyst.
To the best of our knowledge, there are only two
reports about the reduction of α‐cyano‐α,β‐unsaturated
esters.[39,40]
In one of them, Sudalai, et al reported the reduction of
α‐cyano‐α,β‐unsaturated esters using NaBH4 over CoCl2
as a homogeneous catalyst.[39] They performed the reac-
tion in ethanol as solvent at 6 hr. For the reduction of
ethyl‐2‐cyano‐3‐(3‐nitrophenyl) acrylate, they achieved
2‐(Hydroxymethyl)‐3‐(3‐nitrophenyl) propanenitrile in
80% yield which means that they could reduce the alkane
and esters to alkane and alcohols, respectively, but nitro
and cyanide groups remained unreacted.
In other reports, Luis et.al reported two‐step
Knoevenagel reaction‐reduction over a bifunctional cata-
lyst containing Au nanoparticles.[40] They could reduce
the alkane, ester and nitro groups to alkane, alcohol
and amine groups at 24 hr using 20 mmol NaBH4. More-
over, in all cases, the nitro group was reduced during the
reaction.
bIsolated yields.
benzaldehyde dimethyl acetal and ethylcyanoacetate, var-
ious catalysts with the different Ni:Pd molar ratios in
0.1 g poly (SSA‐NVI)/KIT‐6 were prepared and used in
the desired reaction. In these reactions, the total amount
of metals were fixed and considered 0.1 mmol. As we
mentioned before, when only Ni nanoparticles have been
immobilized into the catalyst, just ester and alkene
groups were reduced and the nitro group remained
unreacted while the catalytic performance was 76% in
90 min (Table S3). However, combining palladium with
nickel nanoparticles shows the better catalytic activity
and a different chemo‐selectivity (ester, alkene and nitro
groups were reduced). To evaluate this, different Ni:Pd
molar ratios (0:100, 20:80, 30:70, 50:50, 70:30) have been
tested and showed that the catalyst activities in all
molar ratios were almost the same. However, due to the
lower amount of Pd as an expensive metal used in the
TABLE 3 The amount of acid sites of the catalysts prepared by various monomer molar ratios
Monomer molar ratio
(SSA:NVI)
Amount of
polymer (g)
Theoretical amount
Experimental amount
Entry
of acid (mmol g−1
)
of acid (mmol g−1
)
Percentagea (%)
1
2
3
1:1
2:1
3:1
1
1
1
0.121
0.088
0.056
0.105
0.082
0.043
86
93
76
aThe ratio of the experimental amount to the theoretical amount.
TABLE 4 The amount of base sites of the catalysts prepared by various monomer molar ratios
Monomer molar ratio
(SSA:NVI)
Amount of
polymer (g)
Theoretical value of base
Experimental value of base
(mmol g−1
)
Percentagea
(%)
Entry
(mmol g−1
)
1
2
3
1:1
2:1
3:1
1
1
1
0.121
0.177
0.17
0.08
0.132
0.13
66
74
76
aThe ratio of the experimental amount to the theoretical amount.

JAVAD KALBASI ET AL.
15 of 20
TABLE 6 Sequential one‐pot deacetalization–Knoevenagel condensation reaction of different benzaldehyde dimethyl acetals and active
methylene groups catalyzed by poly (SSA‐NVI)/KIT‐6a
Entry
Aryl carbaldehyde dimethyl acetal
Product
Time (h/min)
Yieldb (%)
1
1.5
93
2
3
1.5
96
95
160 min
4
5
6
3.5
2
92
63
97
3
7
8
2
89
94
0.5
9
2
92
94
10
40 min
11
12
13
4.5
95
97
20 min
5
95
(Continues)

16 of 20
JAVAD KALBASI ET AL.
TABLE 6 (Continued)
Entry
Aryl carbaldehyde dimethyl acetal
Product
Time (h/min)
Yieldb (%)
14
5
95
15
16
17
4
97
94
80
2.8
4.5
18
19
20
1
95
95
20
21
22
70 min
0.5
94
92
85
0.5
23
24
25
40 min
50 min
20 min
96
90
95
aReaction condition: Aryl carbaldehyde dimethyl acetal (1 mmol), active methylene compound (1 mmol), catalyst (0.03 g) and H2O (3 ml) at 45 °C.
bIsolated yields.

JAVAD KALBASI ET AL.
17 of 20
SCHEME 2 Sequential one‐pot
deacetalization–Knoevenagel
condensation‐reduction reaction
TABLE 7 Sequential one‐pot deacetalization–Knoevenagel condensation‐reduction reaction of different benzaldehyde dimethyl acetal
catalyzed by Ni‐Pd@poly (SSA‐NVI)/KIT‐6a
Entry
Benzaldehyde dimethyl acetal
Product
Total time (h/min)
Reduction Time (h/min)
Yieldb (%)
1
2.5
1
90
2
3
2.5
1
1
94
93
220 min
4
5
5.5
2
87
95
220 min
40 min
6
7
8
9
310 min
40 min
40 min
25 min
20 min
90
95
93
94c
1
325 min
50 min
aReaction condition: Aryl carbaldehyde dimethyl acetal (1 mmol), ethylcyanoacetate (1 mmol), catalyst (0.03 g), Ni:Pd molar ratio (70:30), NaBH4 (2 mmol),
H2O (3 mL), 45 °C.
bIsolated yields.
cNaBH4 (6 mmol).
In compare, our catalyst could act as a heterogeneous
tri‐functional catalyst to catalyze the sequential one‐pot
deacetalization–Knoevenagel condensation‐reduction in
water as a green solvent and the reaction was done at just
50 min. Moreover, it could be used for the reduction of
alkene, ester and nitro groups or alkene and ester by a

18 of 20
JAVAD KALBASI ET AL.
SCHEME 3 Sequential one‐pot
deacetalization–Knoevenagel
condensation‐reduction reaction between
3‐nitro benzaldehyde dimethyl acetal and
ethylcyanoacetate over different metal‐
containing catalysts
simple change in the structure of the catalyst. In addition,
it could be reused for several times.
Also, the reusability of Ni‐Pd@poly (SSA‐NVI)/KIT‐6
catalyst was studied in the above‐mentioned reaction. In
this way, the catalyst was separated by filtering after the
completion of the reaction, then washed with diethyl
ether, acetone, and water (or ethanol and water), and
dried at 60 °C for 3 hr. Then the recovered catalyst
immediately reused in the same fresh reaction without
any pre‐activation. The results depicted that the synthe-
sized catalyst could be reused 7 times with acceptable
catalytic activity (Figure S17).
The FE‐SEM images of recycled catalyst exhibited
that the structure of the fresh catalyst is maintained even
after the sixth run (Figure 11). Also, EDS analysis and
FE‐SEM‐mapping of the reused catalyst after the sixth
To ensure the heterogeneity nature of the catalyst, the
one‐pot sequential reaction between 3‐nitro benzalde-
hyde dimethyl acetal and ethylcyanoacetate was started.
Then, it was stopped after 40 min and the catalyst was
separated from the reaction mixture by filtration. Then,
the reaction was continued for an extra 5 hr without the
catalyst. The results showed that the reaction was not
progressed after filtering the catalyst, means that the
reaction was carried out on the heterogeneous surface
of Ni‐Pd@poly (SSA‐NVI)/KIT‐6. It should be mentioned
that according to the results of HPLC analysis, polymer
leaching was not seen during the reaction.
FIGURE 11 FESEM image of the reused catalyst after the sixth run

JAVAD KALBASI ET AL.
19 of 20
FIGURE 12 (a) EDS analysis and (b) FESEM‐elemental‐mapping images of reused catalyst after the sixth run
run showed the suitable distribution of Pd and Ni nano-
particles on the surface (Figure 12).
transfer mechanism with special features including 1.
High efficiency; 2. Uniform distribution of monomers in
the polymer network; 3. Water and oxygen insensitivity;
4. Minimal side products; 5. High reaction rates. Also,
another feature of this polymerization reaction is
minimizing the acid and base neutralization due to the
presence of cross‐linkers and sufficient space between
them.
Moreover, the low‐angle XRD pattern of the recov-
ered catalyst after the sixth run displayed the same pat-
tern of fresh catalyst (Figure S18a). Also, the wide‐angle
XRD pattern of the reused catalyst showed the presence
of Pd NPs on the surface of the catalyst after the sixth
run (Figure S18b).
Furthermore, ICP‐AES results show 0.0211 mmol g−1
Pd and 0.0470 mmol g−1 Ni content of recycled catalyst
after the sixth run that represented only 0.9% and 1.2%
leaching for Pd and Ni, respectively. Therefore, the
decrease in catalyst activity after the sixth run is probably
due to low leaching of Ni‐Pd or aggregations of nanopar-
ticles on the surface of the support.
After preparation and characterization of Ni‐Pd@poly
(SSA‐NVI)/KIT‐6, we used this catalytic system to cata-
lyze the three‐step one‐pot deacetalization‐Knoevenagel
condensation‐reduction reaction. In the reduction step,
this catalyst was able to reduce the C=C bond, ester
(CO2Et) and nitro (NO2) groups in high yield. The impor-
tant point is that the catalyst was able to make catalytic
chemo‐selectivity by changing the metal combination
from alone Ni to Ni‐Pd mixture (alloy) and reduced the
nitro (NO2) group in addition to the C=C, ester (CO2Et)
groups while nitrile group remains unchanged.
4 | CONCLUSIONS
We have demonstrated
a
novel acid–base‐metal
trifunctional catalyst comprising Ni‐Pd@poly (SSA‐
NVI)/KIT‐6 using simple and facile methods. To prepare
this catalyst, firstly, we synthesized bifunctional heteroge-
neous crosslinked polymer as an acid–base function of
catalyst in the pores of KIT‐6, for the first time. We used
thiol‐ene click reaction through the free‐radical chain
ACKNOWLEDGEMENTS
The authors would like to acknowledge financial support
from Kharazmi University.

20 of 20
JAVAD KALBASI ET AL.
[23] W. Dai, M. Zheng, Y. Zhao, S. Liao, G. Ji, J. Cao, Nanoscale Res.
Lett. 2009, 5, 103.
ORCID
Roozbeh Javad Kalbasi
6609
https://orcid.org/0000-0003-3975-
[24] Y. Teng, X. Wu, Q. Zhou, C. Chena, H. Zhao, M. Lan, Sens
Actuators B Chem. 2009, 142, 267.
[25] P. Wang, Z. Wang, J. Li, Y. Bai, Microporous Mesoporous Mater.
2008, 116, 400.
REFERENCES
[26] M. S. Ahmed, S. Jeon, ACS Catal. 2014, 4, 1830.
[1] C. You, C. Yu, X. Yang, Y. Li, H. Huo, Z. Wang, Y. Jiang, X. Xu,
[27] C. Tang, Y. Liu, C. Xu, J. Zhu, X. Wei, L. Zhou, L. He, W. Yang,
K. Lin, New J. Chem. 2018, 42, 4095.
L. Mai, Adv. Funct. Mater. 2017, 28, 1704561.
[2] S. Sobhani, F. Zarifi, J. Skibsted, New J. Chem. 2017, 41, 6219.
[28] T. W. Kim, F. Kleitz, B. Paul, R. Ryoo, J. Am. Chem. Soc. 2005,
127, 7601.
[3] H. Liu, F. G. Xi, W. Sun, N. N. Yang, E. Q. Gao, Inorg. Chem.
2016, 55, 5753.
[29] M. Rezaei, A. N. Chermahini, H. A. Dabbagh, Chem. Eng. J.
2017, 314, 515.
[4] M. J. Climent, A. Corma, S. Iborra, Chem. Rev. 2010, 111,
1072.
[30] L. Xu, C. Wang, J. Guan, J. Solid State Chem. 2014, 213, 250.
[31] R. Kishor, A. K. Ghoshal, RSC Adv. 2016, 6, 898.
[5] Z. Jia, K. Wang, B. Tan, Y. Gu, ACS Catal. 2017, 7, 3693.
[6] D. Wang, B. Wang, Y. Ding, H. Wu, P. Wu, Chem. Commun.
2016, 52, 12817.
[32] Y. Teng, X. Wu, Q. Zhou, C. Chen, H. Zhao, M. Lan, Sens
Actuators B Chem. 2009, 142, 267.
[7] T. Toyao, M. Fujiwaki, Y. Horiuchi, M. Matsuoka, RSC Adv.
2013, 3, 21582.
[33] R. Kishor, A. K. Ghoshal, Chem. Eng. J. 2015, 262, 882.
[34] H. Wu, A. Duan, Z. Zhao, T. Li, R. Prins, X. Zhou, J. Catal.
2014, 317, 303.
[8] P. Li, C. Y. Cao, H. Liu, Y. Yu, W. G. Song, J. Mater. Chem. A
2013, 1, 12804.
[35] M. Li, B. Li, H. F. Xia, D. Ye, J. Wu, Y. Shi, Green Chem. 2014,
16, 2680.
[9] F. Zhang, H. Jiang, X. Li, X. Wu, H. Li, ACS Catal. 2013, 4, 394.
[10] L. C. Lee, J. Lu, M. Weck, C. W. Jones, ACS Catal. 2016, 6, 784.
[36] X. Zhang, P. Zhang, H. Yu, Z. Ma, S. Zhou, Catal Letters. 2015,
145, 784.
[11] L. Xiong, H. Zhang, Z. He, T. Wang, Y. Xu, M. Zhou, K. Huang,
New J. Chem. 2018, 42, 1368.
[37] D. Tessier, A. Rakai, F. Bozon‐Verduraz, J. Chem. Soc., Faraday
Trans. 1992, 88, 741.
[12] P. Li, Y. Yu, H. Liu, C. Y. Cao, W. G. Song, RSC Nanoscale
2014, 6, 442.
[38] G. Vijayakumar, A. Pandurangan, Energy 2017, 140, 1158.
[39] A. R. Jagdale, A. S. Paraskar, A. Sudalai, Synthesis 2009, 4, 660.
[13] A. V. Biradar, V. S. Patil, P. Chandra, D. S. Doke, T. Asefa,
Chem. Commun. 2015, 51, 8496.
[40] S. Montolio, C. Vicent, V. Aseyev, I. Alfonso, M. I. Burguete, H.
[14] K. Nakabayashi, H. Mori, Eur. Polym. J. 2013, 49, 2808.
Tenhu, E. García‐Verdugo, S. V. Luis, ACS Catal. 2016, 6, 7230.
[15] C. E. Hoyle, C. N. Bowman, Angew. Chem. Int. Ed. 2010,
49, 1540.
[16] C. E. Hoyle, A. B. Lowe, C. N. Bowman, Chem. Soc. Rev. 2010,
39, 1355.
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of the
article.
[17] R. Gharibi, H. Yeganeh, Z. Abdali, J. Mater. Sci. 2018, 53, 1581.
[18] C. Peng, W. Pan, L. Bao, S. Chen, Y. Chen, M. Han, Y. Xiong,
W. Xu, Polym. Adv. Technol. 2014, 25, 684.
[19] B. J. Sparks, T. J. Kuchera, M. J. Jungman, A. D. Richardson, D.
A. Savin, S. Hait, J. Lichtenhan, M. F. Striegel, D. L. Patton,
J. Mater. Chem. 2012, 22, 3817.
How to cite this article: Javad Kalbasi R,
Mesgarsaravi N, Gharibi R. Synthesis of
multifunctional polymer containing Ni‐Pd NPs via
thiol‐ene reaction for one‐pot cascade reactions.
Appl Organometal Chem. 2019;e4800. https://doi.
org/10.1002/aoc.4800
[20] S. Hafeez, L. Barner, L. Nebhani, Macromol. Rapid Commun.
2018, 39, 1800169.
[21] M. Zhu, B. He, W. Shi, Y. Feng, J. Ding, J. Li, F. Zeng, Fuel
2010, 89, 2299.
[22] C. Fodor, J. Bozi, M. Blazso, B. Ivan, Macromolecules 2012, 45,
8953.