Cu-doped CoFe2O4 nanoparticles as magnetically recoverable catalyst for C–N cross-coupling reaction

Article abstract of DOI:10.1016/j.catcom.2018.02.014

A new hybrid catalyst has been developed by immobilizing copper acetate onto surface of cobalt ferrite magnetic nanoparticles bearing N–O chelating ligand. The magnetic core of the catalyst was synthesized via ultrasound assisted co-precipitation method and characterized by FT-IR, XRD, EDX, SEM, TEM, TGA and VSM analysis. The catalyst was found to be very active for C–N bond forming reaction. Coupling of amines and aryl boronic acid could be achieved in high yield in methanol in presence of triethylamine at room temperature. After completion of the reaction the catalyst could be recovered using an external magnet and reused for consecutive catalytic cycles without significant decrease in the catalytic activity.

Full text of DOI:10.1016/j.catcom.2018.02.014

Accepted Manuscript
Cu-doped CoFe2O4 nanoparticles as magnetically recoverable
catalyst for C-N cross-coupling reaction
Mintu Maan Dutta, Prodeep Phukan
PII:
DOI:
Reference:
S1566-7367(18)30071-2
doi:10.1016/j.catcom.2018.02.014
CATCOM 5328
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Catalysis Communications
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Revised date:
Accepted date:
6 November 2017
23 January 2018
19 February 2018
Please cite this article as: Mintu Maan Dutta, Prodeep Phukan , Cu-doped CoFe2O4
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ACCEPTED MANUSCRIPT
Cu-doped CoFe2O4 nanoparticles as magnetically recoverable catalyst for C-N
cross-coupling reaction
Mintu Maan Dutta, Prodeep Phukan*
Department of Chemistry, Gauhati University, Guwahati -781014, Assam, India
E-mail: pphukan@yahoo.com

ACCEPTED MANUSCRIPT
ABSTRACT: A new hybrid catalyst has been developed by immobilizing copper acetate onto
surface of cobalt ferrite magnetic nanoparticles bearing N-O chelating ligand. The magnetic core
of the catalyst was synthesized via ultrasound assisted co-precipitation method and
characterized by FT-IR, XRD, EDX, SEM, TEM, TGA and VSM analysis. The catalyst was
found to be very active for C-N bond forming reaction. Coupling of amines and aryl boronic acid
could be achieved in high yield in methanol in presence of triethylamine at room temperature.
After completion of the reaction the catalyst could be recovered using an external magnet and
reused for consecutive catalytic cycles without significant decrease in the catalytic activity.
Keywords: Magnetic nanoparticles,N-arylation, boronic acid, aniline,imidazole

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1. Introduction
In organic synthesis, carbon – heteroatom bonds are very important, as they are present in wide
range of compound starting from biologically active compounds to natural products and from
pharmaceuticals to industrially important compounds [1,2,3].In 1998, Chan, Evans and Lam
developed a mild protocol with Cu-catalyst for oxidative amination of aryl boronic
acids[4,5,6,7]. After this report, a number of modifications have been made in this field to
improve the efficiency of the process by using different copper compounds such as
Cu(OAc)2[8],CuCl[9],Cu(OTf)2[10],CuF2[11]
and
Cu-β-cyclodextrin
complex[12],
Cu[(DMAP)4I]I [13] etc. With time, this method became a popular N-arylation process; due to
easy availability of different copper salts and boronic acids. Besides these, there are several
reports of C-N bond formation reaction using various metals such as Cu, Pd, Ni and Fe [9] [14-
18]. Although homogeneous catalysts provide huge potential for carrying out organic
transformations, catalyst recovery becomes a major problem for practical and industrial
applications [13]. Several attempts were made to develop efficient homogenous catalyst for
Chan-Lam process of C-N bond forming reaction. However, limited efforts have been made to
develop heterogeneous catalytic processes for this particular transformation, with only a few
methods outlined[19-21]. Examples of heterogeneous catalytic approach include the use of
polymer immobilized copper complex [19], copper(I)-exchanged zeolites [20] and copper (II)
oxide nanoparticles [21].These heterogeneous catalyst suffers from some drawbacks such as
longer reaction time (8-24h), high catalyst loading and high reaction temperature [19, 20] which
limits its use. To the best of our knowledge there is no report on the use of magnetic
nanoparticles for carrying out Chan–Lam reaction. Magnetic nanoparticles (MNPs) have several

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advantages over other catalysts because of their unique physical and chemical properties which
include its high surface area to volume ratio, ordered pore arrangement, superparamagnetic
behavior and easy separation from reaction mixture using an external magnet.
We intend to report herein, a new type of hybrid catalyst prepared by immobilizing copper
acetate onto the surface of cobalt ferrite magnetic nanoparticles bearing N-O chelating ligand.
The as synthesized Cu-magnetic catalyst exhibit excellent catalytic activity for Chan-Lam
coupling reaction of both primary and secondary amines with aryl boronic acids.
2. Experimental
General Comment:
Chemicals used are of analytical grade and procured from commercial sources. Column
chromatography was performed with silica gel (230-400 mesh).1H and 13C NMR spectra were
obtained from Bruker 300 MHz spectrometer with CDCl3 as the solvent usingTMS internal
standard.
The synthesized catalyst was characterized by using various characterization techniques such as
FT-IR, XRD, EDX, SEM, TEM, TGA and VSM analysis. X-ray powder diffraction (XRD)
patterns obtained were used for the identification of silica coating and metal incorporation over
CoFe2O4 i.e. CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 samples using a Bruker D-8 Advance X-
ray diffractometer with Cu-Kα radiation at wavelength 1.5418 Å operated at voltage 40 kV and
current 30 mA. The XRD data were collected in the 2θ range of 5-80°. An Affinity-1
SHIMADZU, FT-IR spectrophotometer was used for recording the FT-IR spectra of
CoFe2O4@SiO2-NH2-Furfural-Cu (OAc)2 samples in the form of KBr pallets in mid IR-region of
-1
4000-500 cm . Morphology of the magnetic nanoparticles was investigated by transmission

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electron microscopy (200 KV TEM, JEOLJEM 2100). Chemical composition and morphology
of synthesized CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 were evaluated by JEOL JSM-6360
scanning electron microscope equipped with an energy dispersive X-ray spectrometer (EDX).
The thermo gravimetric analysis (TGA) of copper incorporated samples was recorded on Mettler
Toledo TGA/DSC 1, STAR system analyzer in the temperature range 300K-1023K with heating
rate of 10 K min-1 in nitrogen gas atmosphere. The magnetic properties of the synthesized
CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 nanoparticles were determined by vibrating sample
magnetometer (Lakeshore 7410). 1H and 13C-NMR Spectra were obtained in CDCl3 using
Bruker 300 MHz instrument.
2.1.Procedure for the synthesis of CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 nano magnetic
catalyst
The catalyst was synthesized in four steps (Scheme 1).Initially, the cobalt ferrite magnetic core
was synthesized by following previously reported procedure via an ultrasound assisted co-
precipitation method [22, 23].
APTES,
DCM, Reflux
24h
OH
OH
4
4
4
O
O
2
CHO
2
O
O
O
O
OH
O
O
e
2
e
Si
NH2
O Si
O
N
F
e
OH
OH
OH
F
o
F
Dried at 100 oC
Ethanol,
60 oC, 24h
o
o
C
C
O
C
Cu(OAc)2
Amine-functionalized
cobalt ferrite
Acetone,
R.T, 24h
4
O
O
2
O Si
O
N
APTES: Amino propyl triethoxy silane
e
F
o
AcO Cu
OAc
O
C
Scheme 1: Synthetic route for the synthesis of CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2.
2.1.1. Synthesis of the CoFe2O4@SiO2 –NH2nanocomposite
The as prepared hydrophilic CoFe2O4 nanoparticles 200 mg were dispersed in 20 mL of
deionized water under continuous ultra-sonication. In the meantime,8 mL of aqueous ammonia

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solution (25 wt.%) and 80 mL of ethanol was added to it. Next, 3 mL of TEOS was added drop
wise into the above solution, and it was placed under vigorous stirring condition at room
temperature for 24h. The products were separated using an external magnet and washed several
times with water and dried at 50 °C for 6h.
Amine functionalized cobalt ferrite silica composite was prepared by refluxing 500 mg of
CoFe2O4@SiO2nanoparticles with 2 mmol of 3-aminopropyl-trimethoxysilane (M. Wt.: 221.37
-1
gmol , Density: 0.946 g/mL) in dry dichloromethane (50 mL) for 24h. The solid was separated
with the help of a magnet, washed with methanol and then with dichloromethane, and, finally
dried at 100°C under vacuum for 6h to yield the desired nanoparticles [24].
2.1.2. Synthesis of CoFe2O4@SiO2–NH2–furfural–nanocomposite
The oven dried amino propyl silica composite(500mg) was taken in absolute ethanol (50 mL) in
a 100 round bottomed flask and treated with furfural (5 mmol) at 60 °C for 24h. The ligand-
grafted magnetic-silica composite was separated using an external magnet, washed with ethanol
thoroughly to remove unreacted furfural. It was then dried in air at 95 °C overnight to get the
corresponding Schiff base product.
2.1.3. Synthesis of CoFe2O4@SiO2–NH2–furfural–Cu(OAc)2 catalyst
The catalyst was prepared by stirring a mixture of furfural-grafted amine functionalized cobalt
ferrite (200mg) and copper acetate (90 mg, 0.5 mmol) in acetone (30 mL) at room temperature
for 24h. Initially the copper acetate was sonicated for 30 minutes to get a solution of copper
acetate. Then the pre-synthesized MNPs were added to it and left for stirring. After stirring for
24h, the catalyst was separated using external magnet, washed with acetone till washings were
free from excess copper. It was then dried in air at 95 °C overnight [24]. The catalyst was dried

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at 70 °C in a vacuum oven for 4h before using for Chan- Lam reaction. The probable structures
of catalysts were shown in the Scheme 1.
2.2. General procedure for the Chan-Lam C-N cross-coupling reaction
In a typical reaction, arylboronic acid (1 mmol), amino-compound (1 mmol), catalyst (5 wt.%),
Et3N (2 mmol) were mixed in methanol (5 mL) in a 25 mL round bottomed flask. The reaction
mixture was subjected under continuous stirring at room temperature for 5h. Reaction was
monitored from time to time using TLC. After completion of the reaction, catalyst was separated
with the aid of an external magnet and reaction mixture was taken in ethyl acetate. The organic
layer was washed using brine solution, dried over sodium sulfate. After evaporating the solvent,
the crude product was purified by column chromatography using 230-400 silica mesh. The
recovered catalyst was washed with methanol and ethyl acetate, dried in oven and kept in
desiccator for further use
3. Results and Discussion
3.1 Characterization
The presence of the acetate in the synthesized composite was confirmed from the IR spectra as
-1
shown in Fig. 1. Absorption at 1510 cm is due to the stretching vibrations of the COO- group of
-1
-1
the acetate ion of the copper acetate. Other absorptions bands at 1630 cm , 2860 cm and3400
-1
cm are due to the–C=N of Schiff base, =CH group of propyl group of APTES and –OH
stretching respectively [25].

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Fig. 1. IR Spectra of CoFe2O4@SiO2-NH2-furfural-
Cu(OAc)2
Fig. 2. XRD pattern of CoFe2O4@SiO2-NH2-furfural-
Cu(OAc)2
PXRD pattern of the CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 nanoparticles are shown in Fig. 2.
XRD Pattern reveals the nanocrystalline nature of the sample. Diffraction peaks at 2θ values of
30, 35, 39, 43, 59 and 64 were observed which resembles to the (110), (111), (111), (400), (511)
and (440) diffraction planes respectively. Broad peak from 2θ value between 20-30° resembles
the characteristic peak for amorphous SiO2 in the core shell structure [26]. All the diffraction
peaks match with the JCPDS (International Center for Diffraction Data) of standard CoFe2O4 and
copper nanoparticles. Morphology of the synthesized magnetic nanoparticles and the elemental
analysis was determined using SEM and EDX analysis as shown in SI (Fig.S1, Fig.S2). From the
EDX analysis, the amount of Cu doped was found to be 4.74 wt %. Fig.3 shows the TEM image
of the synthesized CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 composite. TEM image showed that
the particles were nearly spherical. Various concentric rings in the SAED pattern resemble the
crystalline nature of the synthesized composite. Particle size as obtained from the image shows
that most particles are in the range of 5 nm that is better explained from the particle size

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distribution plot (Fig. S3 in SI). Thus, from the above explanation we can infer that the
synthesized composite is in the nano range.
Fig.3. TEM image of (a) CoFe2O4@SiO2-NH2-Furfural-
(b) SAED pattern of CoFe2O4@SiO2-NH2-Furfural-
Cu(OAc)2
Cu(OAc)2
The magnetic behavior of the synthesize nanocomposite was assessed by studying the M-H
curve(Fig. S4 in SI).Figure S5 in SI represents the thermogravimetric analysis of the synthesized
CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 composite. Initial weight loss of ~2.28 % takes place
within 100-150 °C, which may be due to desorption of the water from the surface of the
composite [27]. Thereafter weight loss of ~19.5 % takes place within the range of 300-600 °C
which may be due to the decomposition of organic moiety attached to the surface of cobalt ferrite
nanocatalyst.
3.2. Evaluation of catalytic activity
After successful synthesis of thermally stable, copper acetate incorporated cobalt ferrite
functionalized MNP, we intended to examine its catalytic activity for the Chan–Lam type
C-N cross coupling reactions [20, 28-32].For optimizing the reaction condition, we
initially carried out the reaction of aniline with phenyl boronic acid as model substrates

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using 5wt% of catalyst in the presence of most commonly used base triethylamine and
pyridine. The reaction was carried out in 1 mmol scale using 2 mmol of base in ethanol (5
mL) as solvent at room temperature for 3h (Table 1, entry 1). The progress of the reaction
was monitored by using TLC. We could isolate only 66% of the desired product via column
chromatography using a mixture of petroleum ether and ethyl acetate as eluent. After the
initial survey, the reaction was screened with three more solvents such as methanol,
acetonitrile and DMF. The use of methanol produced the best result with 94% yield. Our
study revealed that an increase in reaction time from 3h to 5h proved more efficient in
terms of yield of the final product (Table 1, entry 2 and 3). We have also investigated the
effect of concentration of catalyst on the reaction keeping all other parameters same. On
decreasing the amount of catalyst to 2 wt.%, the reaction yield was found to decrease
significantly to 65% (Table 1, entry 4) and the use of 10 wt.% of catalyst led to marginal increase
in yield to 96%(Table 1, entry 5). Another study was carried out by changing the nature of
the organic base by replacing Et3N with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and
pyridine and keeping all other condition of the reaction unchanged. This particular
variation rather produced poorer results (Table 1, entry 8 and 9).We have also carried out
the reaction in absence of the Cu catalyst as well as in presence of CoFe2O4, CoFe2O4-SiO2,
CoFe2O4-SiO2-NH2instead of CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2 as catalyst. However,
none of these experiments could produce any fruitful result even after continuing the
reaction for 12h (Table 1, entry 10-13). So, the optimum yield was found by using
equimolar amount (1:1) of the substrates in methanol using 5 wt.% of catalyst at room
temperature(Table 1, entry 3). The turnover frequency (TOF) for this reaction was found
̶
1
to be 41.6 h .

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Table 1. Optimization of reaction condition using CoFe2O4@SiO2-NH2-Furfural-Cu(OAc)2
catalyst
Solvent, Et3N
NH
B(OH)2
NH2
+
Catalyst, r.t.
Entry
1
Solvent
Base
Et3N
Catalyst Conc.(wt.%)
Time (h)
3
Yield (%)b
66
Ethanol
CH3OH
CH3OH
CH3OH
CH3OH
CH3CN
DMF
5
2
3
Et3N
Et3N
Et3N
Et3N
Et3N
Et3N
DBU
5
3
5
82
94
65
96
40
35
20
32
n.r.
n.r.
n.r.
n.r.
5
4
2
5
5
10
5
5
6
5
7
5
5
8
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
5
5
9
Pyridine
Et3N
5
5
10
11
12
13
--
12
12
12
12
Et3N
10 c
10 d
10 e
Et3N
Et3N
aReaction condition: Phenyl boronic acid (1 mmol), Aniline (1 mmol), Base (2 mmol), Solvent (5 mL), r.t.bIsolated
c
d
e
yield after chromatographic purification, CoFe2O4 as catalyst; CoFe2O4-SiO2 as catalyst; CoFe2O4-SiO2-NH2 as
catalyst; n.r.: no reaction.
After getting the optimized reaction condition in hand, we extended the scope of the reaction for
a variety of boronic acid and amino compounds. Accordingly, numbers of substrates that are
structurally and electronically diverse have been employed for this particular C-N cross coupling
reactions. Results are summarized in Table 2. The reaction was found successful for a variety of
primary and secondary amines and heterocycles such as imidazole with different boronic acids.
Optimum amount of 5 wt% (based on the boronic acid) of catalyst was found to be sufficient for

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all the cases in this study at room temperature. Coupling of benzamide with boronic acid could
also be very successfully carried out under the catalytic influence of the new magnetic material
(Table 2, entry 15). This method is applicable to a large variety of substituted boronic acid with
a negligible effect on its yield.
Table 2. Substrate scope of Chan-Lam reaction catalysed by CoFe2O4@SiO2-NH2-
Furfural-Cu (OAc)2 catalyst.
H
N
R2
R1
Solvent, Et3N
Catalyst, r.t.
N
B(OH)2
+
R1
R2
R
R
Ph
N
H
NH
MeO
NH
NH
Br
NH
1e, 87%
1b, 80%
1a, 94%
1d, 82 %
1c, 84%
N
OMe
N
N
Ph
Ph
MeO
N
N
H
N
N
N
H3C
1i, 92%
1f, 78%
1g, 83%
1h, 81%
1j, 75%
N
O2N
N
N
H
N
N
N
F
N
Br
N
N
O
1n, 81%
1m, 72%
1o, 83%
1k, 78%
1l, 85%
Reaction condition: aryl boronic acid (1mmol), Amine (1 mmol), catalyst (5 wt. %), CH3OH (5 mL), r.t., 5h, Yields
reported are isolated yield after chromatographic purification
3.3. Reusability Test:
To test the reusability of the catalyst, the catalyst was separated from the reaction mixture
by using an external magnet. It was then washed with ethyl acetate and methanol, dried in
oven, kept in desiccator for further use. We have examined the reusability of this
heterogeneous catalyst for the N-arylation reaction of aniline and phenyl boronic acid
under the optimized reaction conditions. It was observed that the catalyst could be reused

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for at least seven catalytic cycles without loss in activity (Fig. S6 in SI). To check the
characteristic of spent catalyst, we have carried out Powder XRD analysis of the catalyst after
each cycle. From the analysis, no significant changes in catalyst characteristic were found even
after seven catalytic cycles (Fig. S7 (a) of SI). We have also compared the surface area of the
catalyst, before the reaction and after 7th catalytic cycle of use. The BET-surface area of the
catalyst before carrying out the reaction is 9.2262 m²/g (Fig. S7 (b) of SI), and the surface area of
the catalyst after seventh catalytic cycles is 8.8802 m²/g (Fig. S7 (c) of SI). Thus, there is a slight
decrease in its surface area after reusing the catalyst for seven consecutive times.
4. Conclusions
In conclusion, we have synthesized
nanocatalyst via ultrasound assisted
synthesized by attaching
a
copper incorporated cobalt ferrite magnetic
co-precipitation method. The catalyst was
a
Cu(OAc)2-Schiff base complex onto the surface of
CoFe2O4magnetic nanoparticle. The catalytically active CoFe2O4@SiO2-NH2-Furfural-
Cu(OAc)2 material was successfully applied as a reusable catalyst for the Chan-Lam type
cross coupling reaction of aryl boronic acids with aryl amines and heterocycles. The
catalyst offers several advantages over other catalyst such as high stability, easy
separation of catalyst with the aid of an external magnet and its reusability for successive
reactions without significant loss in its catalytic activity.
Acknowledgments
Financial support from DST, India (Grant No. SR/NM/NS-18/2011(G)) is gratefully
acknowledged. MD thanks UGC for a research fellowship under NFOBC scheme. We

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would like to acknowledge the support from SAIF-GU, SAIF-NEHU,CIF-IITG for all the
analytical facilities during the course of investigations.

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References:
1. G. Evano, N. Blanchard, M. Toumi, Chem. Rev.108 (2008)3054–3131.
2. F. Monnier, M. Taillefer, Angew. Chem. Int. Ed. 47(2008) 3096–3099.
3. L. Liang, Z. Li, X. Zhou, Org. Lett., 11(15) (2009)3294-3297.
4. D. M. T. Chan, K. L. Monaco, R-P. Wang, M. P. Winters, Tetrahedron Lett. 39 (1998) 2933.
5. J. J. Li, Name Reaction, 4th ed.; Springer: Berlin, (2009) 101-104.
6. P. Y. S. Lam, C. G. Clark, S. Saubern, J. Adams, M. P. Winters, D. M. T. Chan, A. Combs,
Tetrahedron Lett. 39(1998) 2941-2944.
7. D. A. Evans, J. L. Katz, T. R. West, Tetrahedron Lett. 39(1998) 2937-2940.
8. I. Gonza´lez, J. Mosquera, C. Guerrero, R. Rodrı´guez, J. Cruces, Org. Lett. 11 (8) (2009)
1677-1680.
9. S-Y. Moon, J. Nam, K. Rathwell, W-S. Kim, Org. Lett.16(2014) 338-341.
10. Z-G. Zheng, J. Wen, N. Wang, B. Wu, X-Q. Yu, Beilstein J. Org. Chem. 4 (2008) 1-6.
11. J-T. Yu, H. Guo, Y. Yi, H. Fei, Y. Jiang, Adv. Synth. Catal. 356(2014) 749-752.
12. B. Kaboudin, Y. Abedi, T. Yokomatsu, Eur. J. Org. Chem. (2011) 6656-6662.
13. S. Roy, M. J. Sarma, B. Kashyap, P. Phukan, Chem. Commun. 52(2016) 1170-1173.
14. D. S. Raghuvanshi, A. K. Gupta, K. N. Singh, Org. Lett. 14(17)(2012)4326-4329.
15. Y. Hirai, Y. Uozumi, Chem. Commun. 46 (2010) 1103-1105.
16. S. Sa, M. B. Gawande, A. Velhinho, J. P. Veiga, N. Bundaleski, J. Trigueiro, A.
Tolstogouzov, O. M. ND. Teodoro, R. Zboril, R. S. Verma, P. S. Branco, Green Chem.
16(2014) 3494-3500.
17. P. Ruiz-Castillo, S. L. Buchwald, Chem. Rev. 116 (2016) 12564-12649.
18. J. Bariwal, E.V. Eycken, Chem. Soc. Rev. 42 (2013) 9283-9303.

ACCEPTED MANUSCRIPT
19. M. Islam, S. Mondal, P. Mondal, A. S. Roy, K. Tuhina, N. Salam, S. Paul, D. Hossain, M.
Mobarok, Transition Met Chem. 36 (2011) 447–458.
20. T. Garnier, R. Sakly, M. Danel, S. Chassaing, P. Pale, Synthesis. 49 (2017) 1223-1230.
21. R. K. Borah, P. K. Raul, A. Mahanta, A. Shchukarev, J-P. Mikkola, A. J. Thakur, Synlett. 28
(2017) 1177-1182.
22. C. Borgohain, K. K. Senapati, D. Mishra, K. C. Sarma, P. Phukan, Nanoscale.
2(2010)2250–2256.
23. K. K. Senapati, S. Roy, C. Borgohain, P. Phukan, J. Mol. Catal. A: Chem. 352(2012) 128–
134.
24. P. R. Likhar, S. Roy, M. Roy, M. L. Kantama, R. L. De, J. Mol. Catal. A: Chem. 271 (2007)
57–62.
25. G. V. Manohara, RSC Adv. 4(2014) 46126-46132.
26. C. S. Gill, B. A. Price, C. W. Jones, J. Catal. 251(2007) 145–152.
27. R. Hosseinzadeh, N. Aghili, M. Tajbakhsh, Catal. Lett. 146 (2016) 193–203.
28. J. P. Collman, M. Zhong, Org. Lett. 2(2000)1233-1236.
29. J. P. Collman, M. Zhong, L. Zeng, S.Costanzo, J. Org. Chem. 66(2001)1528-1531.
30. N. Debreczeni, A. Fodor, Z. Hell, Catal. Lett. 144(2014)1547–1551.
31. K. S. Rao, T-S. Wu, Tetrahedron. 68(2012)7735-7754.

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GRAPHICAL ABSTRACT:
4
O
O
O
Si
OH
N
2
e
F
AcO
o
Cu
O
C
AcO
B(OH)2
NH2
NH
R1
R1

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HIGHLIGHTS





Cu-doped CoFe2O4 magneticnanoparticles forthe C-N coupling
Recovery of catalystusingan external magnetand reusability.
Excellentyield.
Low catalyst loading.
Useful forwide range of aryl boronicacids.