A comparative study of catalytic activity on iron-based carbon nanostructured catalysts with Pd loading: Using the Box–Behnken design (BBD) method in the Suzuki–Miyaura coupling

Article abstract of DOI:10.1002/aoc.6415

Highly dispersed palladium nanoparticles immobilized on surface-modified Fe₃O₄ NPs and magnetic carbon nanostructures (CNSs; carbon nanotubes/graphene oxide) were synthesized and applied as a recyclable and reusable nanocatalyst to achieve palladium (II)-catalyzed Suzuki–Miyaura reaction of arylboronic acid with aryl bromides. Carbon nanostructures with immobilized hydantoin (PH)-Pd complex display excellent stability, including a high performance at low catalyst loading. Magnetic separation prevents catalyst centrifuge or filtration and also contributes to practical techniques for recovery. Next, a response surface method based on a three-level Box–Behnken design was used, which involved three factors: catalyst loading, reaction time, and solvent. The Box–Behnken method was advantageous to parameters optimization for obtaining a yield, with high efficiency and accuracy. As a result of catalytic tests, the TONs and TOFs were calculated from all coupling reactions. The prepared nano-magnetic catalysts, after the catalysis reaction, can be easily recovered through the magnetic field. Evaluated catalytic performance indicates that these types of catalysts can function as effective recyclable catalysts at least five times without losing the initial level of catalytic activity.

Full text of DOI:10.1002/aoc.6415

Received: 7 May 2021
DOI: 10.1002/aoc.6415
Revised: 26 July 2021
Accepted: 2 August 2021
R E S E A R C H A R T I C L E
A comparative study of catalytic activity on iron-based
carbon nanostructured catalysts with Pd loading: Using the
Box–Behnken design (BBD) method in the Suzuki–Miyaura
coupling
Faezeh Moniriyan
| Seyyed Javad Sabounchei
Faculty of Chemistry, Bu-Ali Sina
University, Hamedan, Iran
Abstract
Highly dispersed palladium nanoparticles immobilized on surface-modified
Correspondence
Fe3O4 NPs and magnetic carbon nanostructures (CNSs; carbon nanotubes/
graphene oxide) were synthesized and applied as a recyclable and reusable
nanocatalyst to achieve palladium (II)-catalyzed Suzuki–Miyaura reaction of
arylboronic acid with aryl bromides. Carbon nanostructures with immobilized
hydantoin (PH)-Pd complex display excellent stability, including a high perfor-
mance at low catalyst loading. Magnetic separation prevents catalyst centrifuge
or filtration and also contributes to practical techniques for recovery. Next, a
response surface method based on a three-level Box–Behnken design was used,
which involved three factors: catalyst loading, reaction time, and solvent. The
Box–Behnken method was advantageous to parameters optimization for
obtaining a yield, with high efficiency and accuracy. As a result of catalytic
tests, the TONs and TOFs were calculated from all coupling reactions. The pre-
pared nano-magnetic catalysts, after the catalysis reaction, can be easily recov-
ered through the magnetic field. Evaluated catalytic performance indicates
that these types of catalysts can function as effective recyclable catalysts at
least five times without losing the initial level of catalytic activity.
Seyyed Javad Sabounchei, Faculty of
Chemistry, Bu-Ali Sina University,
Hamedan 65174, Iran.
Email: jsabounchei@basu.ac.ir;
jsabounchei@yahoo.co.uk
Funding information
Bu-Ali-Sina University
K E Y W O R D S
Box–Behnken design (BBD), carbon nanostructures (CNSs), Fe3O4-NPs, nano-magnetic
catalyst, Suzuki–Miyaura Coupling
1 | INTRODUCTION
by solid-supported Pd as a heterogeneous catalyst have
received much attention. Among the solid supports used
For more than 30 years, Pd-catalyzed homogeneous
bonding reactions have been used in C–C coupling reac-
tions such as Heck, Sonogashira, Suzuki, Kumada,
Negishi, Hiyama, and so forth.[1–4] These catalysts have
limitations that hampered their industrial applications,
and the constraints include high expense, non-recyclabil-
ity, and challenges in removal from the products.[5] To
overcome such limitations, coupling reactions catalyzed
in constructing heterogeneous catalysts, carbon
nanostructures (CNSs) are more popular due to their
high thermal resistance, chemical stability, and large sur-
face.[6–10] Recently, research has focused on nano-sized
carbon materials such as graphene oxide (GO) and car-
bon nanotubes (CNTs) to achieve their unique proper-
ties.[11] GO has been considered as a support for catalytic
activities due to its unique properties such as high surface
Appl Organomet Chem. 2021;e6415.
wileyonlinelibrary.com/journal/aoc
© 2021 John Wiley & Sons, Ltd.
1 of 20
https://doi.org/10.1002/aoc.6415

2 of 20
MONIRIYAN AND SABOUNCHEI
area, superior chemical stability, two-dimensional
(2D) structures, and low cost.[12–14] In addition, GO con-
tains many functional groups such as hydroxyl, carbonyl,
and epoxy, which cause these hydrophilic groups to
quickly disperse in water and form a stable colloidal sus-
pension.[15–17] Although GO has been studied extensively
in this field,[18–20] CNTs have also been used as solid sup-
port for catalytic activity in recent years.[21,22] CNTs
behave as rolled cylinders of graphene sheets.[23] Multi-
wall carbon nanotubes (MWCNTs) have exceptional
properties such as structural and thermal stability and
also insolubility in most solvents. They are easily
functionalized and are suitable support for immobilizing
groups have many applications, including in medicine,
textile printing, catalysts, and the production of resins
and plastics.[51–55] In this paper, we design and synthesize
several iron-based nanostructured catalysts. Among Pd-
catalyzed cross-coupling reactions, the reaction of
organohalides with organoboronic acids (Suzuki) has
proven to be a very popular and versatile method for the
formation of carbon-carbon bonding.[56,57] Suzuki–
Miyaura reactions are environmentally benign, have a
high tolerance to different functional groups, are easily
available, have high stability of used substrates, and are
widely used to form natural products, biologically active
pharmaceuticals, and agrochemicals.[58,59] Based on this,
we decided to evaluate and compare the catalytic activity
of magnetic nanocatalysts synthesized by Suzuki–
Miyaura cross-coupling reactions. These nanocomposites
showed high catalytic activity in the C–C cross-coupling
reaction.
However, these catalytic reactions are associated with
a new set of optimization problems. Statistical Design of
Experiments (DoE) is a handy tool and a powerful
approach to identify and optimize the relevant process
conditions.[60] Amongst the 12 known principles of green
chemistry, fewer solvents and reagents are used to pro-
vide less chemical waste, and DoE increases the applica-
tion of green chemistry principles. Therefore, DoE has
provided the ability to enable scientists to accept optimal
response conditions more widely. The traditional optimi-
zation approach has many drawbacks varying one vari-
able at a time (OVAT). DoE is a tool for solving
optimization problems promptly. The reasons are that,
first, the outcomes are highly dependent on the starting
point. It rarely reveals optimal conditions for the most
part. Second, the OVAT approach is laborious and time-
consuming, requires many raw materials, and only looks
at one factor at a time, unable to detect factor interac-
tions. Third, the OVAT approach is not able to separate
the “noise” (the inherent run-to-run variation of a sys-
tem) from a real recovery reaction, unless a large number
of responses are repeated using the same conditions.[61]
Therefore, the barriers to the OVAT approach in optimiz-
ing reactions lead to the broader use of DoE in
optimizing chemical reactions. Also, we recorded excel-
lent turnover number (TON) and frequency (TOF) values
for the catalyst with very low catalyst loading. Overall,
these nano-magnetic catalysts show promising results on
sensitivity, repeatability, and stability.
catalytic species.[24–26] An issue in using
a CNS
immobilized combination is their recovery from the reac-
tion mixture for repeated use. Recycling these catalysts
requires a tedious centrifugation process. Due to their
small size, recycling from the reaction solution is difficult
and leads to a significant reduction in their catalytic
activity. A practical solution is to immobilize the surface
of carbon nanostructures with magnetic iron oxide
nanoparticles (IONPs).[27,28] With the development of
nanoscience, the combination of magnetic nanoparticles
and different nanomaterials has become possible to pre-
pare a multifunctional magnetic nanocatalyst with excel-
lent catalytic properties.[29,30] Magnetic nanoparticles
(MNPs) with their unique magnetic properties have
potential applications in drug delivery, biological sys-
tems, and catalysis reactions.[31–33] Here, a combination
of magnetic nanoparticles (Fe3O4) as magnetically recov-
erable catalysts promises a solution to overcome the
above drawbacks by providing an active surface
for adsorption and immobilization of ligands and
metal.[34–36] It is clear that homogeneous catalysts have
higher catalytic activity than their heterogeneous coun-
terparts, but expensive metal catalysts are difficult to
recycle and lead to waste production and contamination
of products.[37,38] Therefore, as is evident, recyclability
and reusability performance are significant parameters to
develop economic processes.[39–42] Metal nanocatalysts
can be stabilized either by chemical adsorption of pre-
synthesized metal nanoparticles or by direct growth of
magnetic nanoparticles using grafted organic functional
molecules on the support.[43–46] The results of Crooks
and Christensen groups showed high catalytic activity of
the nano-magnetic catalyst for reactions such as Suzuki,
hacking, hydrogenation, and so forth.[47–49] For this pur-
pose, hydantoin ligand and terminal amino groups were
considered to graft from the Fe3O4 supports.
Glycolylurea, also known as hydantoin, is a heterocyclic
organic compound with the formula CH2C(O)NHC(O)
NH, which was discovered in 1861 by the reduction or
hydrogenation of allantoin by Baeyer.[50] Hydantoin
2 | RESULT AND DISCUSSION
In this study, iron-based nanostructures catalysts Pd-
PH@CSMNPs, Pd-PH@CNT-CSMNPs, and Pd-PH@GO-

MONIRIYAN AND SABOUNCHEI
3 of 20
CSMNPs were successfully synthesized. Then their cata-
lytic activity was compared with optimize the Suzuki–
Miyaura cross-coupling reaction in the statistical DoE
approach. In order to magnetically synthesize CNS,
graphite and multi-walled carbon nanotubes were first
oxidized to increase activity by a reported proce-
dure.[35,62] After reacting with Fe3O4 nanoparticles to
obtain a negative charge surface, we coated them with a
thin layer of SiO2. Then hydantoin ligand (PH) was
immobilized onto the Fe3O4@SiO2 surface by the cova-
lent bond. Later, the palladium nanoparticles were
immobilized on the surfaces of PH-coated Fe3O4@SiO2,
based on the formation of PdII nanoparticles. In the next
step, this nano-magnet catalytic was synthesized based
on CNSs (carbon nanotubes [CNTs] and graphene oxide
[GO]). The advantage of the nanocomposites synthesized
by this method is the easy and suitable reaction condi-
tions. They can also be separated from the reaction sys-
tem in a short time by using a magnetic field. Therefore,
they can be used repeatedly without significant reduction
in catalytic activity. A schematic illustration of the prepa-
ration process of Pd-PH@CSMNPs, Pd-PH@CNT-
CSMNPs, and Pd-PH@GO-CSMNPs nano-magnetic cata-
lysts is shown in Scheme 1.
2.1 | Characterization of nano-magnetic
catalysts
In this paper, nano-magnetic catalysts are characterized
by Fourier-transform infrared (FT-IR), X-ray powder dif-
fraction (XRD), energy-dispersive spectroscopy (EDS),
SCHEME 1 Schematic of synthesis
of (a) Pd-PH@CSMNPs and (b) Pd-
PH@CNS-CSMNPs Nano-magnetic
catalysts

4 of 20
MONIRIYAN AND SABOUNCHEI
vibrating sample magnetometer (VSM), scanning elec-
tron microscope (SEM), transmission electron micros-
copy (TEM), inductively coupled plasma emission
spectroscopy (ICP-OES), thermogravimetric analysis
ꢀOH, and ꢀC=O. These active groups act as the nucle-
ation sites of iron oxide nanoparticles. The presence of
iron oxide nanoparticles also leads to a reduction in
oxygen-containing groups during the reaction, which can
be confirmed using FT-IR spectroscopy. Figure 1 shows
the FT-IR spectra of oxidized MWCNTs, Pd-PH@CNT-
CSMNPs, GO, Pd-PH@GO-CSMNPs, Pd-PH@CSMNPs,
and PH.
(TGA),
elemental
mapping,
and
histogram
analysis method.
2.1.1 | NMR analysis
The FT-IR spectra of the products were recorded at
each step of the synthesis of the nano-magnetic catalysts
to investigate the production of the expected products.
The FT-IR spectrum of oxidized MWCNTs is displayed in
Figure 1a that the absorption bands at 3422 cmꢀ1 (which
is assigned to the stretching vibration of OH groups) and
1720 cmꢀ1 (corresponding to the C=O vibrations) shows
the presence of functional groups (COOH) on the surface
of the MWCNTs. As can be seen in Figure 1c, the FT-IR
spectrum of GO represents a broad peak at 3415 cmꢀ1 as
well as another one at 1720 cmꢀ1, which is attributed to
the stretching vibrations of the OH and C=O groups,
respectively. The FT-IR spectrum of hydantoin
ligand (PH) is shown in Figure 1f. Figure 1b,d,e
shows the FT-IR spectra of hybrid magnetic
The 1H-NMR and 13C-NMR spectra of the hydantoin
ligand confirmed the synthesizing and for the H NMR
1
showing the signals of the aromatic, NH(1) and NH(2) at
7.38–8.68, 9.54, and 11.33 ppm, respectively. Also, 13C
NMR of hydantoin ligand demonstrated a chemical shift
in the regions of 69.4, 121.9ꢀ149.6, 155.8, and 173.5 ppm,
which are attributed to the groups of C(5), aromatic
rings, CO(1), and CO(2), respectively (see Figures S1 and
S2 in the Supporting Information).
2.1.2 | FT-IR analysis
The nano-magnetic catalysts were characterized by FT-IR
spectra to confirm the successful attachment. After oxida-
tion of carbon nanostructures (CNTs and GO) by mixed
acid solution (H2SO4/HNO3), the CNSs surface contains
many oxygen-containing active groups such as ꢀCOOꢀ,
nanoparticles,
CSMNPs, and Pd-PH@CSMNPs, respectively.
Previous work has shown that FT-IR spectra of mag-
netite, which has two strong infrared absorption bands at
570 cmꢀ1 and 390 cmꢀ1, can be attributed to the Fe–O
Pd-PH@CNT-CSMNPs, Pd-PH@GO-
FIGURE 1 FT-IR spectra of (a) oxidized
MWCNTs, (b) Pd-PH@CNT-CSMNPs, (c) GO,
(d) Pd-PH@GO-CSMNPs, (e) Pd-PH@CSMNPs,
and (f) PH

MONIRIYAN AND SABOUNCHEI
5 of 20
stretching, thus confirming the presence of Fe3O4 in the
samples.[63] The absorption bands at 1210, 1087, 947, and
473 cmꢀ1 were also ascribed to the stretching vibrations
of SiO2, indicating the coating of the silica shell on the
magnetite surface. Based on the spectra, the C–Cl peaks
are removed after binding the hydantoin ligand.
According to the spectra, the stretching vibration of the
C=O group decreased, and starching vibration of the C–
N and C=N groups (ꢁ1331 and ꢁ1653 cmꢀ1) appeared
after hydantoin ligand bonding on the surface of the
nanocatalysts. The peak at 1720 cmꢀ1, corresponding to
the hydantoin cycle, shifted towards lower wavenumbers
after the metal bonds in the magnetic nanocatalyst. This
adsorption peak is observed at 1657 cmꢀ1, which con-
firms that palladium chloride is successfully anchored
onto the surface of nanocomposites. A comparison of the
IR spectra mentioned above indicates the successful com-
bination of nanocatalysts.
2.1.3 | FE-SEM analysis
Scanning electron microscopy (SEM) was investigated to
reveal the morphological properties of the nanocatalysts.
Figure 2 shows the SEM images of samples Pd-
PH@CNT-CSMNPs, GO, Pd-PH@GO-CSMNPs, and Pd-
PH@CSMNPs.
The presence of spherical Fe3O4 NPs, with diameters
up to ꢁ40 nm, was confirmed in each sample. The SEM
image in Figure 2a is an indication that the CNTs are
uniformly filled with magnetic iron oxide (Fe3O4)
nanoparticles. These images confirm our method for
large-scale CNTs filling with Fe3O4 nanoparticles and
also maintains the filling process of the CNTs backbone
mechanical integrity. At the edges of CNTs (for example,
the red circle in Figure 2b), the brightness is higher than
in other areas because these areas have much more
oxygen-containing groups that can facilitate the
FIGURE 2 SEM images in several different magnifications of Pd-PH@CNT-CSMNPs (a–c), GO (d), Pd-PH@GO-CSMNPs (e, f), and Pd-
PH@CSMNPs (g–i)

6 of 20
MONIRIYAN AND SABOUNCHEI
accumulation of Fe3O4 nanoparticles. Scanning electron
microscopy (SEM) images of (Pd-PH@CNT-CSMNPs)
showed the presence of CNTs filaments of average diam-
eter ꢁ49 nm (Figure 2c). It is observed that the mean
diameter (Pd-PH@CNT-CSMNPs) is higher than pristine
MWCNTs.[64]
showed the characteristic peak at 2θ = 10ꢂ, which con-
firms the synthesis of the sample of GO. The XRD spec-
trum of the synthesized samples Pd-PH@CNT-CSMNPs,
Pd-PH@GO-CSMNPs, and Pd-PH@CSMNPs show a for-
mation of Fe3O4 nanoparticles, which is consistent with
previous reports.[65]
Figure 2d shows the SEM image of pure GO. The
SEM image of Pd-PH@GO-CSMNPs (Figure 2e,f) dis-
played the Fe3O4 NPs coverage over the surface of the
nano-magnetic catalyst. The presence of abundant oxy-
gen at the surface and edges might provide additional
sites that enable high iron nanoparticle loading.
Figure 2g–i shows the nanoparticle size and typical SEM
image of Pd-PH@CSMNPs. As shown in the picture,
most of the prepared NPs are spherical-shaped and their
average diameter is about 20–30 nm.
Relatively sharp diffraction peaks indicate that Fe3O4
nanoparticles have relatively high crystallization. The
XRD pattern of the synthesized nanocomposite (Pd-
PH@CNT-CSMNPs) and (Pd-PH@GO-CSMNPs) shows a
peak attributable to the carbon phase CNTs and GO,
respectively. The peak regions and relative intensities are
consistent with XRD standard data (JCPDS no. 19-0629),
and the presence peaks at 18.46ꢂ, 30.66ꢂ, 35.85ꢂ, 43.64ꢂ,
53.95ꢂ, 57.40ꢂ, and 63.08ꢂ are associated with the (111),
(220), (311), (400), (422), (511), and (440) crystal planes of
Fe3O4, respectively (see Table S1). The absence of any
additional peaks belonging to the other phases indicates
good crystallization and high purity of the nano-magnetic
catalysts.
2.1.4 | XRD analysis
The phase composition and crystallographic structure of
MWCNT, Pd-PH@CNT-CSMNPs, GO, Pd-PH@GO-
CSMNPs, and Pd-PH@CSMNPs composites are deter-
mined by X-ray powder diffraction (XRD), as shown in
Figure 3.
The peaks 2θ = 26.5ꢂ and 40.6ꢂ in MWCNT can be
attributed to (002) and (110) CNTs planes. The diffraction
peak at 40.6ꢂ confirms the multi-walled structure of car-
bon nanotubes. The X-ray diffraction pattern of GO
2.1.5 | EDS analysis
To confirm the synthesis of the nano-magnetic cata-
lysts, energy dispersive spectroscopy (EDS) was mea-
sured for the prepared catalysts PH@CNT-CSMNPs,
PH@GO-CSMNPs, and PH@CSMNPs, as shown in
Figure 4.
FIGURE 3 The XRD patterns of GO,
MWCNT, Pd-PH@GO-CSMNPs, Pd-
PH@CSMNPs, and Pd-PH@CNT-CSMNPs

MONIRIYAN AND SABOUNCHEI
7 of 20
FIGURE 4 EDS analysis for elemental
composition of PH@GO-CSMNPs (a),
PH@CNT-CSMNPs (b), and Pd-PH@CSMNPs
(c) nano-magnetic catalysts
FIGURE 5 (a) Magnetization curves of Pd-
PH@CNT-CSMNPs, Pd-PH@CSMNPs, and Pd-
PH@GO-CSMNPs samples; (b) photograph of
nano-magnetic catalyst (Pd-PH@GO-CSMNPs)
dispersed in ethanol (right) and its response to a
magnet (left)
The EDS spectra of the nanocomposites revealed the
presence of C, O, N, Cl, Si, Fe, and Pd elements, which
the elements of Fe arise from Fe3O4, the element of Si
arises from SiO2, the elements of Pd arise from the Pd
nanoparticles, and the C and O mainly come from
hydantoin ligand (PH) and some oxygen-containing
functional groups of CNTs and GO (Figure 4a–c). It
confirms the presence of magnetic nanoparticles
(MNPs), PH, and PdCl2 groups on the surface of CNSs.
Additionally, the Pd loading of the nanocatalysts was
confirmed by measuring the weight percentage of the
palladium in the samples by the ICP-OES analysis. The
amount of Pd on the supports was determined as
19.11%, 21.45%, and 14.15% for Pd-PH@CNT-CSMNPs,
Pd-PH@GO-CSMNPs, and Pd-PH@CSMNPs Respec-
tively. As we expected, the ICP-OES and EDS measure-
ments for nano-magnetic catalysts also proved the
presence of Pd nanoparticles.

8 of 20
MONIRIYAN AND SABOUNCHEI
2.1.6 | VSM analysis
Figure 5b. They also disperse quickly as soon as the
magnet is removed.
Figure 5a shows the magnetic performance of Pd-
PH@CNT-CSMNPs, Pd-PH@GO-CSMNPs, and Pd-
PH@CSMNPs samples by VSM analyzer at room temper-
ature. Magnetic curves showed that all samples were
superparamagnetic at room temperature.
2.1.7 | TEM and histogram analysis
To further illustrate the successful functionalization of
the synthesized nano-magnetic catalysts, transmission
electron microscopy (TEM) was performed. Figure 6a,c,e
shows the TEM micrographs of the Pd-PH@CNT-
CSMNPs, Pd-PH@GO-CSMNPs, and Pd-PH@CSMNPs
samples, respectively.
Identification of the heterogeneous surface with the
random distribution of Fe3O4 was possible by forming
small spheres of MNPs.Also, the particle size can be
explained through histogram diagrams. Histogram dia-
grams of all three samples are given in Figure 6b,d,f.
Because smaller nanoparticles cause more dispersion,
the more excellent dispersion of these active sites
directly affects the catalytic activity.[66] The obtained
particle size distribution histogram showed that the
particle size was in the range of 10–70 nm, and the
majority of particles (70–65%) were in the range of
ꢁ25–35 nm.
The saturation magnetization values for Pd-
PH@CSMNPs,
Pd-PH@GO-CSMNPs,
and
Pd-
PH@CNT-CSMNPs were 27.13, 31.72, and 42.1
emu gꢀ1, respectively. The results showed that with
the increase of carbon nanostructures, the magnetiza-
tion of hybrids is significantly reduced. These behav-
iors indicate that the synthesized samples exhibit a
superparamagnetic behavior due to the presence of
ultra-small
Fe3O4
NPs.
However,
magnetic
nanocatalysts can be removed from the solution in
10 s using a supermagnet. To investigate the colloid
stability of the composite materials, the synthesized
samples can be easily dispersed in ethanol and can be
highly stable at room temperature for at least
6 months. These nano-magnetic catalysts can be
quickly separated from the solution by holding the
sample near a commercial magnet, as shown in
FIGURE 6 TEM micrograph and
histogram of the particle size
distribution for Pd-PH@CNT-CSMNPs
(a and b), Pd-PH@GO-CSMNPs (c and
d), and Pd-PH@CSMNPs (e and f)
samples

MONIRIYAN AND SABOUNCHEI
9 of 20
2.1.8 | TGA analysis
95.67 wt% (Figure 7). For the Pd-PH@CSMNPs
nanoparticles, the main weight loss occurred above
700ꢂC due to the lack of significant organic components.
However, this sample had much higher thermal stability
rather than both Pd-PH@GO-CSMNPs and Pd-
PH@CNT-CSMNPs. The highest weight loss is observed
above 210ꢂC, which can be attributed to the breakdown
of the CONHPd groups conjugated with Fe3O4
nanoparticles of the Pd-PH@CSMNPs nanocomposite.
The thermogram of Pd-PH@CNT-CSMNPs showed two
main stages of weight losses a 3% of weight loss at 300ꢂC
and 7% above 500ꢂC. The initial losses are attributed to
the decomposition of labile oxygen deriving from func-
tional groups and organic components, and the removal
of most of the stable functionalities deriving from Fe3O4
NPs. The TGA curve of Pd-PH@GO-CSMNPs
nanocomposite showed a profile similar to Pd-PH@CNT-
CSMNPs, although it revealed a difference of weight loss
of 14% in comparison to the Pd-PH@CNT-CSMNPs sys-
tem in the temperature range 400–600ꢂC.
The thermal stability of Pd-PH@CNT-CSMNPs, Pd-
PH@GO-CSMNPs, and Pd-PH@CSMNPs samples was
investigated via thermogravimetric analysis (TGA), as
shown in Figure 7.
Thermal gravimetric analysis showed a successful
grafting of Fe3O4 NPs on the supporting surface by
increasing the thermal stability of these nanocomposites
compared with their nanocarbon structures.[67,68] The
residual weight at 600ꢂC for Pd-PH@CNT-CSMNPs was
about 84.81 wt% and for Pd-PH@GO-CSMNPs was about
71.72 wt% as compared with the Pd-PH@CSMNPs with
2.1.9 | Elemental mapping analysis
To investigate the uniformity of the elements, the ele-
mental mapping of catalyst Pd-PH@GO-CSMNPs was
examined (Figure 8a–i). These figures clearly show that
FIGURE 7 TGA curves of Pd-PH@CSMNPs, Pd-PH@GO-
CSMNPs, and Pd-PH@CNT-CSMNPs nanocomposites
FIGURE 8 The corresponding
elemental mapping pattern of Pd-
PH@GO-CSMNPs nano-magnetic
catalyst (a–i)

10 of 20
MONIRIYAN AND SABOUNCHEI
all the elements are dispersed uniformly on the surface of
the functionalized graphene oxide.
reaction are the amount of solvent (A), catalyst (B), and
time (C), while the response of interest (dependent vari-
able) is the yield of the reaction. These three variables
have the most significant impact on production. Box–
Behnken experimental design was used to evaluate the
effect of each variable.[70,71] The response level results
were analyzed based on the percentage of efficiency to
determine the optimal conditions using DMF solvent
with nano-magnetic catalyst. We began our investigation
of the cross-coupling reaction using bromobenzene as the
electrophile and phenylboronic acid as the nucleophile.
A list of the variables examined and the level of depen-
dent responses is depicted in Table 1.
Accordingly, the amount of solvent ranged from 5 to
20 ml, catalyst loading ranged from 0.005–0.01 mol%,
and reaction time ranged from 1 to 3 h. In our study, the
Box–Behnken design (BBD) was applied with three fac-
tors at three levels, with three center points, one response
(yield%), and a total of 15 experiments. Design-Expert
Software (Version 11, Stat-Ease, Inc., Minneapolis, MN
55413) was applied for data analysis.Our target is to max-
imize the final yield of the Suzuki–Miyaura reaction com-
pounds. In general, it has been proven that the catalytic
efficiency of these nano-magnetic catalysts is very high
and the Suzuki corresponding product has been obtained
with high purity in most reactions. A comparison of the
efficiency of catalysts 1, 2, and 3, which catalyze
the Suzuki C-C coupling reactions under the same condi-
tions, is also shown in Figure 9.
2.2 | Optimization of reaction for Suzuki
coupling reactions using design of
experiments (DoE) method
In recent decades, carbon–carbon bonding reactions have
received widespread attention as a powerful and useful
tool for the synthesis of organic compounds. Suzuki–
Miyaura cross-coupling reactions are one of the most
widely used coupling reactions. The controversial issue in
the chemical industry is the toxicity and high cost of pal-
ladium metal. For this reason, heterogeneous and mag-
netic catalysts have been considered due to the easy
recovery of the reaction mixture and the possibility of
reuse. Current research is directed towards increasing the
efficiency of these catalysts. For this purpose, the cata-
lytic activity of three synthesized nano-magnetic catalysts
in the Suzuki–Miyaura cross-coupling reactions was
investigated and compared.In this study, we report using
the DoE technique to minimize experimentation pro-
cesses and optimize the gathered data. A large number of
parameters studied, such as catalyst, solvent, and time,
suggested a DoE approach. To begin the study of catalytic
activity, we need a model reaction using the couplings of
phenylboronic acid with bromobenzene. In the begin-
ning, the Pd-PH@CSMNPs (catalyst 1), Pd-PH@CNT-
CSMNPs (catalyst 2), and Pd-PH@GO-CSMNPs (catalyst
3) were selected as the catalyst. The amount of solvent is
the second important parameter. According to previously
published reports, the most common solvent for the
Suzuki–Miawara connection is dimethylformamide
(DMF).[69] Another influential factor is the reaction time.
So, three main factors that can affect the yield of the
Among the presented catalysts, Catalyst 1 has no car-
bon structure and shows lower efficiency. On the other
hand, catalysts with carbon nanotube and graphene car-
bon structures led to higher yields in catalysts 2 and 3.
These results suggest that the addition of carbon struc-
tures to metals with catalytic properties, such as palla-
dium, increases the catalytic properties. Also, by
TABLE 1 The levels of independent variables examined, the unit, and the range of dependent response of the biphenyl production using
Box–Behnken design
Coded level
Variable
Factor coding
Unit
ml
low level (ꢀ1)
5
0
high level (+1)
Solvent
A
B
C
12.5
20
0.01
3
Catalyst (1, 2, and 3)
Reaction time
mol%
hour
0.005
1
0.0075
2

MONIRIYAN AND SABOUNCHEI
11 of 20
FIGURE 9 Comparative catalytic study for
catalysts 1, 2, and 3 by coupling bromobenzene
and phenylboronic acid, by optimizing the
conditions with the Box–Behnken method for
phenylboronic acid (1 mmol), bromobenzene
(0.75 mmol), catalyst (7.5 ꢃ 10ꢀ3 mol%), DMF,
130ꢂC, 2 h
TABLE 2 Box–Behnken design conditions for optimizing the biphenyl production with corresponding experimental results
Variables
(unit)
Solvent
(DMF)
Catalyst
(mol%)
Time
Yield catalyst 3
(hour)
Run
1
A
B
C
1
2
3
2
1
2
1
2
1
2
2
3
2
3
3
(%)
82
77
45
92
86
77
65
83
76
86
55
54
84
87
67
20
0.0075
0.005
0.0075
0.0075
0.01
2
5
3
5
4
12.5
12.5
20
5
6
0.01
7
5
0.0075
0.005
0.005
0.0075
0.01
8
20
9
12.5
12.5
5
10
11
12
13
14
15
12.5
12.5
12.5
20
0.01
0.0075
0.005
0.0075
increasing the catalytic activity of 3 compared with 2, it
was found that the smaller size of the nanoparticles and
the larger surface area increase the catalytic activity
and greater efficiency. Therefore, nano-magnetic catalyst
3 was chosen as a proper catalyst with high yield activity
toward the Suzuki cross-coupling reaction (see Table S2).
Yield in the design space ranged from 45% to 92%, and
curvature was detected from yield at the center point con-
ditions. Therefore DoE was carried out, using response
surface methodology (RSM). Table 2 summarizes the
results of the relevant tests.
Figure 10a,b shows the normal plot of residuals and
predicted versus actual plots comparing the experimental
values with the predicted values for model evaluation.
The plots show a minor deviation from the line, between
the actual and predicted values and the normal plot of
residuals, which determines the accuracy of the model
prediction.
Two-dimensional contour graphs and three dimen-
sions surface plots were used to analyze the combined
effect of factors on efficiency. Figures 11, 12, and 13 show
the response surface curves and contour plots for yield
and the three independent variables. The effect and inter-
action of each of the independent variables were exam-
ined. The response surfaces displayed an exact peak point
Table 3 shows the p value of the term type (which
was significantly less than 0.05), along with the analysis
of variance (ANOVA) summary of the RSM.

12 of 20
MONIRIYAN AND SABOUNCHEI
TABLE 3 Analysis of variance (ANOVA) of the experimental result of the BBD
Source
Model
A-Solvent
B-Catalyst
C-Time
AB
Sum of squares
2700.18
561.12
325.13
392.00
64.00
df
9
Mean square
300.02
561.12
325.13
392.00
64.00
F value
19.38
36.24
21.00
25.32
4.13
p value
0.0023
0.0018
0.0059
0.0040
0.0977
0.5531
0.0028
0.0016
0.4527
0.0047
significant
1
1
1
1
AC
6.25
1
6.25
0.4037
29.85
38.26
0.6624
23.45
BC
A2
B2
C2
462.25
592.41
10.26
1
462.25
592.41
10.26
1
1
363.10
77.42
1
363.10
15.48
Residual
Lack of fit
Pure error
Cor total
5
42.75
3
14.25
0.8221
0.5897
not significant
34.67
2
17.33
2777.60
14
FIGURE 10 Graphical plot of normal plot
of residuals (a) predicted versus actual values
(b)
FIGURE 11 (a) Response surface curve
and (b) contour plot. The response surface plot
and contour plot of the yield biphenyl (%) for
the interaction effects solvent with time
that revealed the optimum condition and the highest
yield in product production, which were achieved inside
the design boundary area for all three variables. Solvent
(A) interaction in the range of 5 to 20 and reaction time
(C) from 1 to 3 h at constant Pd-PH@GO-CSMNPs cata-
lyst amount (B) of 0.0075 mol% at the response surface
shown in Figure 11a is provided. It is observed that the
highest yield is produced with 12.5 ml of solvent and 2 h

MONIRIYAN AND SABOUNCHEI
13 of 20
FIGURE 12 (a) Response surface curve
and (b) contour plot. The response surface plot
and contour plot of the yield biphenyl (%) for
the interaction effects time with catalyst amount
FIGURE 13 (a) Response surface curve
and (b) contour plot. The response surface plot
and contour plot of the yield biphenyl (%) for
the interaction effects solvent with catalyst
amount
reaction time. In the contour plot of the conversion
response model in Figure 11b, from front to back, with
color code changing from blue to red, the contour lines
indicate that the yield of biphenyl is above 60%, 70%, and
80%, respectively. The yield increased due to the increas-
ing amount of solvent. Yield increased with more solvent,
but with excess solvent, the performance began to
decrease.
The response surface illustrated in Figure 12a repre-
sents the interaction effect when the Pd-PH@GO-
CSMNPs catalyst amount (B) was varied from 0.01 to
0.005 mol% and reaction time (C) was increased from
1 to 3 h at a constant solvent (A) of 12.5 ml. The highest
yield percentage can be seen in the 0.0075 mol% of cata-
lyst and 2-h reaction time. As the amount of catalyst
increases, the reaction's efficiency increases, but from a
specific value onwards, increasing the catalyst does not
have a significant effect on increasing product efficiency,
so a small amount is preferred due to the high cost of the
catalyst. Furthermore, in the contour plot of the yield
response model in Figure 12b, from back to front, with
color code changing from green to orange-red, the con-
tour lines indicate that the efficiency is above 60%, 70%,
80%, and 90%, respectively.
The response surface shown in Figure 13a describes
the interaction influence of solvent (A) from 5 to 20, and
Pd-PH@GO-CSMNPs catalyst amount (B) from 0.01 to
0.005 mol% at a constant reaction time (C) of 2 h. As can
be seen, the highest yield percentage was produced in a
12.5-ml solvent and 0.0075 mol% catalyst. As the solvent
increased, the yield also increased. By adding more sol-
vent, the yield increased steadily, but when the amount
exceeded 12.5 ml, the excess solvent reduced the yield.
Less use of the catalyst also increases the percentage of
yield, and additional catalysts reduce the percentage
of the product (contour plot in Figure 13b).
Therefore, the optimum point of the design involves a
12.5-ml solvent, 0.0075 mol% of Pd-PH@GO-CSMNPs
catalyst, furthermore a 2-h reaction time. Optimal condi-
tions lead to the maximum predicted yield value of 92%.
2.3 | The substrate scope of reactions
Suzuki–Miyaura cross-coupling
With the optimized conditions obtained for the cross-
coupling reactions with catalyst 3, we then investigated
the substrate scope (Table 4).

14 of 20
MONIRIYAN AND SABOUNCHEI
TABLE 4 Suzuki coupling reactions of various aryl bromides and arylboronic acid over catalyst 3a
Aryl bromide
R2
-H
Product
Yieldb (%)
TONc
TOFd (h1ꢀ
)
92
12,267
6133
1
1a
1b
-COMe
-CHO
91
95
12,133
12,667
6066
6333
1c
2a
2b
-Et
-H
89
88
11,867
11,733
5933
5866
2
-Et
-H
85
92
11,333
12,267
5666
6133
3a
3
3b
-Et
-Et
87
95
11,600
12,667
5800
6333
4
5
4a
5a

MONIRIYAN AND SABOUNCHEI
15 of 20
TABLE 4 (Continued)
Aryl bromide
R2
-H
Product
Yieldb (%)
TONc
TOFd (h1ꢀ
)
80
10,667
5333
5b
-H
-CN
-Et
89
84
76
11,867
11,200
10,133
5933
5600
5066
6a
6b
6
7
8
7a
8a
8b
-Et
-H
96
89
93
12,800
11,867
12,400
6400
5933
6200
-CHO
9
9a
aReaction conditions: 0.75 mmol aryl bromide, 1 mmol arylboronic acid, 1.5 mmol K2CO3, 12.5 ml DMF, 7.5 ꢃ 10ꢀ3 mol% of Pd-PH@GO-CSMNPs catalyst,
130ꢂC, 2 h.
bIsolated yield.
cTON = (turnover number, yield of product per mol of Pd).
dTOF = (turn over frequency, TON/time of reaction).

16 of 20
MONIRIYAN AND SABOUNCHEI
Reactions with arylboronic acids contain the
As can be seen from Table 5, PH@GO-CSMNPs cata-
lysts show high reaction yields compared with other
catalysts at lower reaction times. In addition, it is a supe-
rior ligand to some of the previously reported catalysts in
terms of thermal stability, non-toxicity, and cheapness,
ease of separation, reusability, and very low catalyst
loading.
electron-withdrawing and electron-donating functional
groups proceeded very well with a wide range of aryl
bromides. Optimized conditions were determined to be
the following: the use of Pd-PH@GO-CSMNPs as a cat-
alyst, K2CO3 as a base in DMF at 130ꢂC. It is notewor-
thy that the activity of the catalytic reaction depends
only on the surface exposed active sites and is regularly
performed on the surface of the nano-magnetic catalyst.
This promising trend could also improve and show bet-
ter performance by supporting materials and adjusting
the nanocrystallization of the particle size. From these
studies, efficiency, easy recovery, and reusability show
that the increased activity for the Pd-PH@GO-CSMNPs
nano-magnetic catalyst compared with homogeneous
analogs, exclusively originate from the carbon nanopar-
ticle size, the presence of Fe3O4 magnetic nanoparticles
(which in turn are a powerful catalyst) and palladium
metal nanoparticles originate. These results predicted
that the activation step of carbon halogen bonding in
Pd-PH@GO-CSMNPs nano-magnetic catalyst and conse-
quently catalytic activity increased significantly. After
purification, all compounds were identified by 1H
NMR, 13C NMR, and FT-IR spectroscopy (see
Figures S3–S34 in the Supporting Information). In this
study, outstanding TON and TOF (12,800/6400) were
obtained using a very small amount of Pd-PH@GO-
CSMNPs nano-magnetic catalyst and the findings are
presented in Table 4. These results suggest that this cat-
alyst can be used in most relevant industrial applica-
tions. To evaluate the catalytic performance of
PH@GO-CSMNPs, its catalytic activity was compared
with that of other palladium-based catalysts reported in
the Suzuki–Miyaura reactions, and the results are pres-
ented in Table 5.
2.4 | Stability and recycling of the Pd-
PH@GO-CSMNPs nano-magnetic catalyst
Finally, the recyclability of Pd-PH@GO-CSMNPs was
investigated using the coupling of phenylboronic acid
and 1-bromo-4-nitrobenzene in the presence of 0.0075
mol% of the catalyst under optimal conditions. As shown
in Figure 14, this catalyst can be used up to five times
without significant loss of catalytic performance.
FIGURE 14 Catalytic recyclability test for successive five runs
of 4-nitro-biphenyl. Reaction conditions: phenylboronic acid
(1 mmol), 1-bromo-4-nitrobenzene (0.75 mmol), catalyst
3 (7.5 ꢃ 10ꢀ3 mol %), DMF, 130ꢂC and 2 h
TABLE 5 Comparison results of PH@GO-CSMNPs catalyst with other palladium-based catalysts in the coupling reaction of aryl
bromides and arylboronic acid
Entry
Pd Catalyst
GO-NHC-Pd
GO-SB/Pd
Time (h)
Yield (%)
mol% of Pd
TON
1079
106
740
600
90
TOF (h1ꢀ
540
19
)
Ref.
[72]
1
2
5.6
20
3.5
24
4
60
85
74
60
90
80
95
91
95
54
96
0.03
0.8
[73]
[74]
[75]
[76]
[77]
[19]
[78]
[79]
[80]
2
3
Pd–G
0.1
37
4
Fe3O4@SiO2–4-AMTT-Pd(II)
Pd(II)–NHC
GO-NH2-Pd2+
GO-NHC-Pd2+
PdNPs
0.1
171
3.75
20
5
1.0
6
1.0
80
7
3
0.25
380
96
127
8
8
12
8
1.0
9
Pd-1/FSG
0.1
950
329
119
13.7
6400
10
11
Pd(II)–MCM-4
PH@GO-CSMNPs
24
2
ꢃ10ꢀ32.82
ꢃ10ꢀ37.5
12,800
Present study

MONIRIYAN AND SABOUNCHEI
17 of 20
This magnetic catalyst retains 81% of its original cata-
lytic activity at the end of the fifth cycle of Suzuki–
Miyaura coupling reactions. These results indicate that
Pd-PH@GO-CSMNPs is a highly stable catalyst that can
be easily separated from the reaction mixture by a super-
magnet for repeated use.To confirm the heterogeneity of
the catalyst, we performed a hot filtration test for the cou-
pling reaction between bromobenzene and phe-
nylboronic acid using the Pd-PH@GO-CSMNPs catalyst
under the same conditions according to previous stud-
ies.[81,82] The reaction was allowed to proceed under opti-
mal reaction conditions for 1:20 h (yield of 75%), then the
nano-magnetic catalyst was separated from the reaction
mixture. After the reaction was continued for more than
30 min, no increase in the yield of the product was
observed. This result confirms the heterogeneous nature
of the nanocatalyst. However, the study of recycled Pd-
PH@GO-CSMNPs composite shows another aspect of
interest in this type of catalyst.As shown in Figure 15a,b,
the TEM and FE-SEM images of the recovered catalyst
after the fifth cycle show that the catalyst morphology
remained unchanged. Moreover, the XRD and FT-IR
spectra (Figure 15c,d) were studied in which they show
no apparent changes in peaks for both fresh and recycled
catalysts. These results show the good stability of the Pd-
PH@GO-CSMNPs nano-magnetic catalyst.
Co. (Mashhad, Iran). Natural graphite powder
(>99.0%) was obtained from Sigma-Aldrich. The
rest of the reagents and solvents used in
this research are commercially available and
purchased from commercial suppliers (Merck and
Sigma-Aldrich).
3.2 | Apparatus and measurements
FT-IR spectra were recorded using a Shimadzu 435-U-
04 spectrophotometer through KBr plates in the wave-
1
length range of 400–4000 cmꢀ1. The H NMR and 13C
NMR spectra were recorded with a 400-MHz Bruker or
on a 90-MHz Jeol spectrometer using DMSO-d6 or
CDCl3 as a solvent at room temperature. Also, melting
points were measured using an SMPI apparatus. XRD
pattern of the samples was recorded with an X0 Pert
Pro, Panalytical Co. at 25ꢂC using monochromatic Cu
Kα radiation. The morphology of the samples was
observed using an FE-SEM/EDS instrument (Zeiss,
SMT AG, and TESCAN, MIRA3). Transmission elec-
tron microscopy (TEM) and TEM histogram were per-
formed with a Phillips EM 2085 electron microscope.
The Pd loading of nanocomposites was determined
using inductively coupled plasma emission spectros-
copy (ICP-OES) by (730-ES simultaneous CCD, Varian,
USA). The magnetic behavior of nanoparticles was
3 | EXPERIMENTAL SECTION
3.1 | Reagents and materials
measured using
a vibrating sample magnetometer
(VSM) (MDKFT, Kashan, Iran). An ultrasonic water
bath model parsonic 2600s (Pars Nahand Co., Iran)
was applied for the homogeneous dispersion of
samples.
MWCNT (average diameter 30 nm) has been
purchased from Iranian Nanomaterials Pioneers
FIGURE 15 (a) TEM, (b) FE-SEM,
(c) XRD, and (d) FT-IR analysis of
PH@GO-CSMNPs catalyst after fifth
recycling experiment

18 of 20
MONIRIYAN AND SABOUNCHEI
3.3 | Preparation of the nano-magnetic
catalysts
carbonate following a literature procedure by Eknoian–
Webb reaction.[87] Hydantoin ligand solution (0.5 g) in
100 ml of ethanol, a few drops of trimethylamine and
0.5 g (CNS-CSMNPs) were added to a flask under ultra-
sound irradiation for 30 min at 50ꢂC. Then the reaction
under reflux conditions was stirred for 4 h in a nitrogen
atmosphere. The reaction mixture was then cooled to
room temperature, and the nanoparticles were collected
by magnets and washed three times with ethanol.
3.3.1 | CNS-CSMNPs
To prepare nano-magnetic catalysts (2 and 3),
silanization of the silica-coated magnetite nanoparticles
on the CNSs was synthesized in three steps. The surface
of the MWCNTs was oxidized in a manner previously
reported in the literature.[83]
At first, 500 mg of MWCNT was added to 50 ml of
H2SO4/HNO3 solution, and the suspension was refluxed for
4 h at 60ꢂC. The oxidized MWCNTs were filtered and
washed three times with 200 ml of deionized water
and dried in a vacuum oven. Also, graphene oxide (GO) was
first synthesized according to the method described by
Hummers and Offeman from natural graphite powder.[84]
In the next step, FeCl3ꢄ6H2O (2.92g), and FeCl2ꢄ4H2O
(1.07g) in 150 ml of deionized water under a nitrogen
atmosphere were added to the oxidized CNSs (0.5 g) by
vigorous stirring at 80ꢂC. Then, 20 ml of 28% aqueous
ammonia solution was added dropwise to the suspended
solid nanoparticles under mechanical agitation. Next, the
nanoparticles were separated by a supermagnet and
washed three times with deionized water and methanol
and then dried under vacuum (CNS-MNPs). In the fol-
lowing silanization of the silica-coated magnetite
nanoparticles prepared according to the Stober and
Moghanian method.[85,86] Dry particles (CNS-MNPs) (2 g)
were dispersed in 100 ml dry ethanol and 30 min was
sonicated. Then, 2.5 ml of 25 mol% concentrated aqueous
ammonia solution and 7.5 ml (32.04 mmol) of
tetraethylorthosilicate (TEOS) were added dropwise to
the suspended solid nanoparticles under mechanical stir-
ring and the reaction was refluxed for 20 h. After cooling
the mixture, the resulting precipitate was separated from
the solution using supermagnet; after several rinses with
water, it was dried in a vacuum for 24 h (CNS-SMNPs).
In the next step, 2 of the magnetic nanoparticles obtained
in the previous step were dispersed in 100 ml of ethanol/
deionized water mixture (volume ratio, 10:1). Then,
3-chloropropyltrimethoxysilane (CPTMS) (2 ml) was
added dropwise to the above suspension, and the above
solution was stirred continuously for 18 h at 60ꢂC. The
resulting solid was collected by a supermagnet and
washed three times with deionized water and ethanol
and dried at 60ꢂC (CNS-CSMNPs).
3.3.3 | Pd-PH@CNS-CSMNPs
The palladium (II) chloride was immobilized on the sur-
face of PH@CNS-CSMNPs by reacting PH@CNS-
CSMNPs with PdCl2 in 50-ml ethanol. For this purpose,
0.75 g (5.5 mmol) of PdCl2 was added to 1 g of well-
dispersed PH@CNS-C
SMNPs in 40-ml of ethanol. The mixture was stirred for
24 h at 60ꢂC. The obtained product, which is
Pd(II) complex anchored on the surface of functionalized
magnetic carbon nanostructures (designated as Pd-
PH@CNS-CSMNPs), was washed with 60 ml of acetone–
ethanol mixture (1:1, v/v) (three times each time with
20 ml) to remove the excess PdCl2, and prepared suspen-
sion was collected by supermagnet then dried in an oven at
60ꢂC for 24 h. In the next step, a nano-magnetic catalyst
(1) was synthesized. Fe3O4 NPs were also prepared using
the chemical co-precipitation technique. An aqueous solu-
tion of salts FeCl3.6H2O (2.92 g) and FeCl2.4H2O (1.07 g) in
deionized water at 80ꢂC with the addition of NH4OH (25%,
15 ml) was mixed under rapid stirring and the product was
a black powder. The black precipitate was magnetically
separated and washed with ethanol and water (volume
ratio, 2:1) and dried at 60ꢂC. The rest of the steps were per-
formed according to the method mentioned above.
3.4 | General experimental procedure for
Suzuki cross-coupling reaction
Based on optimized conditions, a 10-ml oven-dried con-
taining a magnetic stirring bar was charged with a nano-
magnetic catalyst (7.5 ꢃ 10ꢀ3 mol%), aryl bromide
(0.75 mmol), arylboronic acid (1 mmol), K2CO3
(1.5 mmol), and DMF (12.5 ml) were added, and the reac-
tion was sealed and stirred at 130ꢂC for a specified time.
The reaction mixture was then cooled to room tempera-
ture. After solvent evaporation, the crude product was
purified by thin-layer chromatography (TLC) and ana-
3.3.2 | PH@CNS-CSMNPs
1
lyzed by FT-IR, H, and 13C NMR (see Supporting Infor-
The ligand, 5-(4-pyridyl)-5-phenylhydantoin (PH), was
synthesized from 4-benzoyl-pyridine to ammonium
mation). Yields were calculated against the consumption
of the aryl bromides.

MONIRIYAN AND SABOUNCHEI
19 of 20
4 | CONCLUSIONS
REFERENCES
[1] A. Jakob, B. Milde, P. Ecorchard, C. Schreiner, H. Lang,
J. Organomet. Chem. 2008, 693(26), 3821.
[2] G. Albano, L. A. Aronica, Eur. J. Org. Chem. 2017, 2017, 7204.
[3] L. Zhang, J. Wu, J. Am. Chem. Soc. 2008, 130(37), 12250.
Here, we have prepared highly dispersible, recyclable,
and reusable catalysts based on iron and carbon
nanostructures
(graphene
oxide/multi-walled
[4] N. D. Patel, J. D. Sieber, S. Tcyrulnikov, B. J. Simmons, D.
Rivalti, K. Duvvuri, Y. Zhang, D. A. Gao, K. R. Fandrick, N.
Haddad, K. S. Lao, H. P. R. Mangunuru, S. Biswas, B. Qu, N.
Grinberg, S. Pennino, H. Lee, J. J. Song, B. F. Gupton, N. K.
Garg, M. C. Kozlowski, C. H. Senanayake, ACS Catal. 2018,
8(11), 10190.
[5] L. Yin, J. Liebscher, Chem. Rev. 2007, 107(1), 133.
[6] H. Song, Q. Zhu, X. Zheng, X. Chen, J. Mater. Chem. A 2015,
3(19), 10368.
[7] T. Baran, I. Sargin, M. Kaya, A. Mentes¸, T. Ceter, J. Colloid
Interface Sci. 2017, 486, 194.
[8] J.-M. Yan, S.-J. Li, S.-S. Yi, B.-R. Wulan, W.-T. Zheng, Q.
Jiang, Adv. Mater. 2018, 30(12), 1703038.
[9] S. Li, Y. Ping, J.-M. Yan, H.-L. Wang, M. Wu, Q. Jiang,
J. Mater. Chem. A 2015, 3(28), 14535.
[10] S.-J. Li, D. Bao, M.-M. Shi, B.-R. Wulan, J.-M. Yan, Q. Jiang,
Adv. Mater. 2017, 29(33), 1700001.
[11] A. D. Moghadam, E. Omrani, P. L. Menezes, P. K. Rohatgi,
Compos. Part B Eng. 2015, 77, 402.
[12] B. Qiu, M. Xing, J. Zhang, Chem. Soc. Rev. 2018, 47(6), 2165.
carbon nanotubes) with a simple process and analyzed
by various analytical methods. These catalysts were
magnetically active, so due to their magnetic iron oxide
nanoparticles, carbon nanostructure, and palladium
metal, they were a great potential application for cataly-
sis in the Suzuki–Miyaura coupling reactions. The
response surface methodology with Box–Behnken
design was used to determine a feasible experimental
design to optimize the coupling conditions of the
Suzuki–Miyaura reactions.
A
comparative study
between Fe3O4 NPs, CNT, and GO-supported
nanocatalyst indicates that the GO-supported catalyst
has a superior catalytic activity compared to other cata-
lysts. The three parameters of solvent ratio, catalyst
loading, and reaction time have the most significant
effect on production. The experimental results indicated
that the optimum conditions for the nano-magnetic cat-
alyst
Pd-PH@GO-CSMNPs
were
12.5 ml
of
[13] R.
Yadav,
A.
Subhash,
N.
Chemmenchery,
B.
dimethylformamide, 7.5 ꢃ 10ꢀ3 mol% catalyst, and 2 h
reaction time. The effect of all three independent
parameters was statistically investigated on the yield for
biphenyl production at 130ꢂC. The temperature was the
most critical factor in this reaction. Most importantly,
the catalyst is quite easy to recycle and has excellent
recyclability even after five cycles without losing effi-
ciency. The heterogeneous catalysts produced on these
bases are the basis for future nanocomposites with
their inherent recovering and multi-functionalizable
properties.
Kandasubramanian, Ind. Eng. Chem. Res. 2018, 57(29), 9333.
[14] X. Fan, G. Zhang, F. Zhang, Chem. Soc. Rev. 2015, 44(10),
3023.
[15] G. Zhao, X. Li, M. Huang, Z. Zhen, Y. Zhong, Q. Chen, X.
Zhao, Y. He, R. Hu, T. Yang, R. Zhang, C. Li, J. Kong, J.-B.
Xu, R. S. Ruoff, H. Zhu, Chem. Soc. Rev. 2017, 46(15), 4417.
[16] S. Majumder, B. Satpati, S. Kumar, S. Banerjee, ACS Appl.
Nano Mater. 2018, 1(8), 3945.
[17] M. He, G. Fei, Z. Zheng, Z. Cheng, Z. Wang, H. Xia, Langmuir
2019, 35(10), 3694.
[18] C. Bai, Q. Zhao, Y. Li, G. Zhang, F. Zhang, X. Fan, Catal. Lett.
2014, 144(9), 1617.
[19] N. Shang, S. Gao, C. Feng, H. Zhang, C. Wang, Z. Wang, RSC
Adv. 2013, 3(44), 21863.
ACKNOWLEDGMENT
We are grateful to Bu-Ali-Sina University for financial
support.
[20] S. J. Hoseini, M. Dehghani, H. Nasrabadi, Cat. Sci. Technol.
2014, 4(4), 1078.
[21] S. Mahouche Chergui, A. Ledebt, F. Mammeri, F. Herbst, B.
Carbonnier, H. Ben Romdhane, M. Delamar, M. M. Chehimi,
Langmuir 2010, 26(20), 16115.
[22] H. Veisi, A. Khazaei, M. Safaei, D. Kordestani, J. Mol. Catal. A:
Chem. 2014, 382, 106.
[23] S. Iijima, P. M. Ajayan, T. Ichihashi, Phys. Rev. Lett. 1992,
69(21), 3100.
AUTHOR CONTRIBUTIONS
Faezeh Moniriyan: Data curation; formal analysis;
investigation; methodology; project administration; soft-
ware. Seyed Javad Sabounchei: Conceptualization.
DATA AVAILABILITY STATEMENT
The data that supports the findings of this study are avail-
able in the supporting information of this article.
[24] J. M. Planeix, N. Coustel, B. Coq, V. Brotons, P. S. Kumbhar,
R. Dutartre, P. Geneste, P. Bernier, P. M. Ajayan, J. Am. Chem.
Soc. 1994, 116(17), 7935.
[25] X. Tan, W. Deng, M. Liu, Q. Zhang, Y. Wang, Chem. Commun.
2009, (46), 7179.
ORCID
[26] M. Salavati-Niasari, M. Bazarganipour, Appl. Surf. Sci. 2008,
255(5), 2963.
Faezeh Moniriyan https://orcid.org/0000-0001-5063-
7008
[27] V. Georgakilas, V. Tzitzios, D. Gournis, D. Petridis, Chem.
Mater. 2005, 17(7), 1613.
Seyyed Javad Sabounchei https://orcid.org/0000-0001-
[28] H. Tan, W. Feng, P. Ji, Bioresour. Technol. 2012, 115, 172.
9000-5304

20 of 20
MONIRIYAN AND SABOUNCHEI
[29] E. V. Shevchenko, D. V. Talapin, C. B. Murray, S. O'Brien,
J. Am. Chem. Soc. 2006, 128(11), 3620.
[30] F. X. Redl, K.-S. Cho, C. B. Murray, S. O'Brien, Nature 2003,
423(6943), 968.
[61] G. D. Bowden, B. J. Pichler, A. Maurer, Sci. Rep. 2019, 9(1), 1.
[62] M. Kim, C. K. Hong, S. Choe, S. E. Shim, J. Polym. Sci. Part A
Polym. Chem. 2007, 45(19), 4413.
ꢀ
[63] R. Dañova, R. Olejnik, P. Slobodian, J. Matyas, Polymers
[31] C. Bergemann, D. Müller-Schulte, J. Oster, L. à Brassard, A. S.
Lübbe, J. Magn. Magn. Mater. 1999, 194(1–3), 45.
[32] M. Arruebo, R. Fernandez-Pacheco, M. R. Ibarra, J.
Santamaría, Nano Today 2007, 2(3), 22.
[33] S. Sobhani, Z. Pakdin-Parizi, Appl. Catal. A. Gen. 2014,
479, 112.
[34] J. Liu, X. Peng, W. Sun, Y. Zhao, C. Xia, Org. Lett. 2008,
10(18), 3933.
(Basel) 2020, 12(3), 713.
[64] Y. Yuan, J. Chen, Nanomaterials 2016, 6(3), 36.
[65] Y. Zhan, R. Zhao, Y. Lei, F. Meng, J. Zhong, X. Liu, J. Magn.
Magn. Mater. 2011, 323(7), 1006.
[66] M. Qamar, M. Muneer, Desalination 2009, 249(2), 535.
[67] F. Najafi, M. Rajabi, Int. Nano Lett. 2015, 5(4), 187.
[68] M. S. Polyakov, T. V. Basova, Макрогетероциклы 2017,
10(1), 31.
ꢀ
[35] S. Ding, Y. Xing, M. Radosz, Y. Shen, Macromolecules 2006,
39(19), 6399.
[69] M. B. Ibrahim, B. El Ali, M. Fettouhi, L. Ouahab, Appl.
Organomet. Chem. 2015, 29(6), 400.
[36] U. Laska, C. G. Frost, G. J. Price, P. K. Plucinski, J. Catal.
2009, 268(2), 318.
[70] D. Das, R. Thakur, A. K. Pradhan, J. Electrostat. 2012,
70(6), 469.
[37] A. Corma, H. Garcia, Adv. Synth. Catal. 2006, 348(12–13),
1391.
[38] J. A. Widegren, R. G. Finke, J. Mol. Catal. A: Chem. 2003,
198(1–2), 317.
[71] Y. Yin, J. Wang, Energy Fuel 2016, 30(5), 4096.
[72] V. Kandathil, A. Siddiqa, A. Patra, B. Kulkarni, M.
Kempasiddaiah, B. S. Sasidhar, S. A. Patil, C. S. Rout, S. A.
Patil, Appl. Organomet. Chem. 2020, 34(11), e5924.
[73] A. Zarnegaryan, Z. Dehbanipour, D. Elhamifar, Polyhedron
2019, 170, 530.
[39] I. D. Inaloo, S. Majnooni, European J. Org. Chem. 2019,
2019(37), 6359.
ꢀ
[40] I. Dindarloo Inaloo, S. Majnooni, H. Eslahi, M. Esmaeilpour,
Appl. Organomet. Chem. 2020, 34(8), e5662.
[41] I. D. Inaloo, S. Majnooni, H. Eslahi, M. Esmaeilpour, New
J. Chem. 2020, 44(31), 13266.
[74] M. Gomez-Martínez, E. Buxaderas, I. M. Pastor, D. A. Alonso,
J. Mol. Catal. A: Chem. 2015, 404, 1.
[75] A. R. Hajipour, M. Kalantari Tarrari, S. Jajarmi, Appl.
Organomet. Chem. 2018, 32(3), e4171.
[42] I. Dindarloo Inaloo, M. Esmaeilpour, S. Majnooni, A. Reza
Oveisi, ChemCatChem 2020, 12(21), 5486.
[76] Q. Xu, W.-L. Duan, Z.-Y. Lei, Z.-B. Zhu, M. Shi, Tetrahedron
2005, 61(47), 11225.
[43] J. Ge, T. Huynh, Y. Hu, Y. Yin, Nano Lett. 2008, 8(3), 931.
[44] Z. Wang, P. Xiao, B. Shen, N. He, Colloids Surf. A Physicochem.
Eng. Asp. 2006, 276(1–3), 116.
[77] N. Shang, C. Feng, H. Zhang, S. Gao, R. Tang, C. Wang, Z.
Wang, Cat. Com. 2013, 40, 111.
[78] M. Nasrollahzadeh, S. M. Sajadi, M. Maham, J. Mol. Catal. A:
Chem. 2015, 396, 297.
[45] Y.-C. Chang, D.-H. Chen, J. Hazard. Mater. 2009,
165(1–3), 664.
[79] L. Wang, C. Cai, J. Mol. Catal. A: Chem. 2009, 306(1–2), 97.
[80] S. Bhunia, R. Sen, S. Koner, Inorg. Chim. Acta 2010, 363(14),
3993.
[81] T. Baran, Catal. Lett. 2019, 149(6), 1496.
[82] T. Baran, Catal. Lett. 2019, 149(6), 1721.
[83] J. Shen, W. Huang, L. Wu, Y. Hu, M. Ye, Mater. Sci. Eng. A
2007, 464(1–2), 151.
[46] D. K. Yi, S. S. Lee, J. Y. Ying, Chem. Mater. 2006, 18(10), 2459.
[47] O. M. Wilson, M. R. Knecht, J. C. Garcia-Martinez, R. M.
Crooks, J. Am. Chem. Soc. 2006, 128(14), 4510.
[48] E. H. Rahim, F. S. Kamounah, J. Frederiksen, J. B.
Christensen, Nano Lett. 2001, 1(9), 499.
[49] M. Pittelkow, K. Moth-Poulsen, U. Boas, J. B. Christensen,
Langmuir 2003, 19(18), 7682.
[84] W. S. Hummers Jr., R. E. Offeman, J. Am. Chem. Soc. 1958,
[50] A. Baeyer, Justus Liebigs Ann. Chem. 1861, 117(2), 178.
[51] E. Ware, Chem. Rev. 1950, 46(3), 403.
[52] P. E. Allegretti, M. de las Mercedes Schiavoni, C. Guzman, A.
80(6), 1339.
[85] W. Stöber, A. Fink, E. Bohn, J. Colloid Interface Sci. 1968,
26(1), 62.
ꢀ
Ponzinibbio, J. J. P. Furlong, Eur. J. Mass Spectrom. 2007,
13(4), 291.
[53] S. D. Worley, Y. Chen, Biocidal polystyrene hydantoin parti-
cles, 2005.
[54] J. W. Hanson, N. C. Myrianthopoulos, M. A. S. Harvey, D. W.
Smith, J. Pediatr. 1976, 89(4), 662.
[86] H. Moghanian, A. Mobinikhaledi, A. G. Blackman, E.
Sarough-Farahani, RSC Adv. 2014, 4(54), 28176.
[87] M. W. Eknoian, T. R. Webb, S. D. Worley, A. Braswell, J.
Hadley, Acta Crystallogr. Sect. C Cryst. Struct. Commun. 1999,
55(3), 405.
[55] J. Safari, L. Javadian, C. R. Chim. 2013, 16(12), 1165.
[56] T. Baran, N. Yılmaz Baran, A. Mentes¸, Appl. Organomet.
Chem. 2018, 32(2), e4075.
[57] T. Baran, N. Yımaz Baran, A. Mentes¸, Appl. Organomet. Chem.
2018, 32(2), e4076.
SUPPORTING INFORMATION
Additional supporting information may be found in the
online version of the article at the publisher's website.
[58] T. Baran, I. Sargin, M. Kaya, A. Mentes¸, J. Mol. Catal. A: Chem.
2016, 420, 216.
[59] T. Baran, Int. J. Biol. Macromol. 2019, 127, 232.
[60] S. Verma, Y. Lan, R. Gokhale, D. J. Burgess, Int. J. Pharm.
2009, 377(1–2), 185.
How to cite this article: F. Moniriyan, S.
J. Sabounchei, Appl Organomet Chem 2021, e6415.
https://doi.org/10.1002/aoc.6415