Synthesis of thiospinel CuCo2S4 and CuCo2S4/reduced-graphene oxide nanohybrids as highly effective catalysts for the Sonogashira reaction

Article abstract of DOI:10.1039/c6nj02771g

Formation of a carbon-carbon bond using the transition metal catalyzed Sonogashira coupling reaction is an indispensable tool in synthetic organic chemistry. Initially complexes of Pd were used as catalysts, however advances in catalyst design fuelled the development of Cu catalysts, which are cheaper and more environmentally benign than complexes of Pd. This is the first paper that reports the application of thiospinels in the Sonogashira reaction. Thiospinel CuCo₂S₄ and CuCo₂S₄/reduced-graphene oxide (RGO) nanohybrids were first synthesized through a simple solvothermal approach. Our studies show that all of these nanohybrids are suitable for the Sonogashira reaction in water at room temperature. Compared to classical reactions, this method consistently has the advantages of a green solvent, short reaction times, low catalyst loading, high yields and reusability of the catalysts and a facile method for the preparation of the catalysts. The CuCo₂S₄ and CuCo₂S₄/RGO nanohybrids showed highly improved catalytic activity towards aryl chloride derivatives compared to other catalysts that have been reported.

Full text of DOI:10.1039/c6nj02771g

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Jason B. Benedict et al.
The role of atropisomers on the photo-reactivity and fatigue of
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Synthesis of thiospinel CuCo2S4 and CuCo2S4/ reduced-graphene oxide
nanohybrids as highly effective catalysts for the Sonogashira reaction†
Roghayeh Hashemi Fath and S. Jafar Hoseini*
Department of Chemistry, Faculty of Sciences, Yasouj University, Yasouj 7591874831, Iran
Abstract
Formation of carbon – carbon bond using transition metal catalyzed Sonogashira coupling
reaction is an indispensable tool in synthetic organic chemistry. Initially complexes of Pd were
used as catalysts, however advances in catalyst design fuelled the development of Cu catalysts,
which are cheaper and more environmentally benign than the complexes of Pd. This is the first
paper that reports the application of thiospinels in the Sonogashira reaction. Thiospinel CuCo2S4
and CuCo2S4/ reducedꢀgraphene oxide (RGO) nanohybrids were firstly synthesized through a
simple solvothermal approach. Our studies show that all of these nanohybrids are suitable for the
Sonogashira reaction in water at room temperature. Compared to classical reactions, this method
consistently has the advantages of a green solvent, short reaction times, low catalyst loading,
high yields and reusability of the catalysts and a facile method for the preparation of the
catalysts. The CuCo2S4 and CuCo2S4/RGO nanohybrids showed highly improved catalytic
activity toward aryl chloride derivatives as compared with other catalysts that have been
reported.
*
Corresponding author: Eꢀmail: jhosseini@yu.ac.ir, sjhoseini54@yahoo.com, Fax: +98 74 33342172; Tel: +98 74
33223048.
1

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Introduction
The Sonogashira reaction is used in numerous syntheses of natural products, for instance,
enediyne antibiotics, as well as in the preparation of conducting polymers, liquid crystals and
other engineering materials.1,2 An important trend in modern development of synthetic ways is
the search for cheaper starting materials, ligands, and catalysts. For example copper derivatives
are replacing very expensive palladium in the crossꢀcoupling reaction and related processes.3 The
Pdꢀfree Cuꢀcatalyzed Sonogashira crossꢀcoupling reaction has been attracting a significant
interest for last two decades since its discovery.4 Large number of new catalytic systems based
on copper have been proposed. These catalysts involve not only phosphines,5 but also Oꢀ and Nꢀ
donating ligands,6 some of which are quite simple and readily available. Following principles of
green chemistry, aqueous,7 solventꢀfree8 and ligandꢀfree9 systems were reported. In this study, to
the best of our knowledge, there is no report concerning the application of thiospinels in the
Sonogashira reaction.
Sulfides of transition metal that adopt the spinel crystal structure are generally referred to as
thiospinels. Thiospinels have an ideal formula of MM′2S4, where M and M′ are normally divalent
and trivalent metal cations, respectively, though other oxidation numbers and offꢀstoichiometry
formulas sometimes can be accommodated.10 Among the most common thiospinels are single
metal systems (M = M′), such as Co3S4, Ni3S4, and Fe3S4. Exchange of some of the cobalt metal
in Co3S4 with copper metal generates a solid solution, ultimately forming the end member
CuCo2S4. CuCo2S4, which is the mineral carrollite, is a normal spinel, with Cu occupying the
tetrahedral sites and Co occupying octahedral site. Thiospinels are widely studied for their
electronic, magnetic, and catalytic properties.11
2

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Graphene, a single atom thick layer of sp2 hybridized carbon atoms tightly packed into a
twoꢀdimensional honeycomb lattice, is the basic building unit for graphitic materials of all other
dimensionalities.12 The properties of graphene such as chemical, high thermal, and mechanical
stability as well as high surface area represent desirable characteristics as 2D support layers for
metallic nanoparticles (NPs) in heterogeneous catalysis, chemical sensors, fuel cells, and
hydrogen storage applications.13 Recently, graphene, graphene oxide (GO) and functionalized
GO have been considered as excellent carbon supports for metalꢀcatalyzed carbon–carbon
coupling applications.14
In this study, we have prepared thiospinel CuCo2S4 and CuCo2S4/ reducedꢀgraphene oxide
(RGO) nanohybrids via a facile solvothermal method. Reducing the consumption of precious
metals such as Pd by bimetallization with a lowꢀcost and nonꢀnoble metal is a popular approach.
In this article, using Cu and Co metals can decrease the cost of catalysts. Then, these
nanohybrids are used as nonꢀphosphine catalysts for the Sonogashira reaction in water. The
CuCo2S4/RGO nanohybrid was used as efficient catalyst in the Sonogashira coupling reaction,
with the lowest loading of 0.4 mol% of Cu, the reaction was completed after 20 min at room
temperature (r.t.). These results demonstrate the remarkable catalytic activity of CuCo2S4/RGO
nanohybrid with a turnover number (TON) of 240 and turnover frequency (TOF) of 720 hꢀ1.
Metal–metal interaction has a significant effect on oxidative addition and reductive elimination
as key steps in Sonogashira reaction. Elements of the firstꢀrow of transition metals facilitate the
reductive elimination step as final step in Sonogashira reaction. Thiospinel CuCo2S4 and
CuCo2S4/RGO nanohybrids showed higher catalytic activity in the Sonogashira reaction due to
the appropriate interaction between copper and cobalt metals.
3

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Experimental
All of the chemical compounds were purchased from SigmaꢀAldrich and Merck companies. The
powder Xꢀray diffraction (XRD) patterns were obtained by a Bruker AXS (D8, Advance)
instrument employing the reflection Bragg–Brentano geometry with CuꢀKα radiation. The
surface atomic concentration and chemical composition of the samples were investigated by Xꢀ
ray photoelectron spectroscopy (XPS) equipped with an Al Kαxꢀray source at energy of 1486.6
eV in an ultrahigh vacuum (UHV) system with a base pressure lower than 2×10−9 Torr.
Transmission electron microscopy (TEM) images were taken with a Philips CMꢀ10 microscope
operated at 100 kV. The loading amount of copper was determined using an inductively coupled
1
plasma (ICP) analyzer (Varian, VistaꢀPro). H NMR spectra were taken with a Bruker 400 MHz
13
ultraꢀshield spectrometer using CDCl3 as the solvent. C NMR was recorded on a Varian 100
MHz spectrometer.
Preparation of CuCo2S4/RGO nanohybrid
The GO was synthesized from natural graphite flakes by a modified Hummers method.14aꢀc, 15 In
a typical synthesis of CuCo2S4/RGO nanohybrid, Co(NO3)2 (0.6 mmol) and Cu(NO3)2 (0.3
mmol) were dissolved in 60 ml of GO/ ethylene glycol (EG) suspension and reflux at 80 °C for 2
h. Then, thiourea (0.18 mmol) was added into the above suspension. Finally, the mixture was
transferred into an autoclave (75 ml), and heated at 200 °C for 8 h. After being cooled to room
temperature, the mixture was centrifuged and black crystals were separated, washed with water
and ethanol and dried in vacuum at 60 °C for 8 h. For comparisons, CuCo2S4 nanoparticle was
synthesized using a reported procedure.16
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General procedure for Sonogashira carbon–carbon coupling reaction
Aryl halide (0.5 mmol) and phenylacetylene (0.75 mmol) were added to a flask containing the
catalyst (3 mg) and K2CO3 (1 mmol) in 5 ml of H2O at room temperature. After the reaction was
completed (monitored by TLC), the catalyst was separated and dichloromethane (3 × 5 ml) was
added to the reaction solution. The organic layer was separated and dried over anhydrous
MgSO4. Evaporation of the solvent gave the desired organic product, then analyzed by 1H NMR
spectra with those of authentic sample and the details are given in the ESI.† The turnover
number (TON = mol of product per mol of catalyst) and turnover frequency (TOF = TON per
time (h)) were calculated on the basis of the amount of diarylacetylene product formed.
Results and discussion
Physicochemical characterization of the catalysts
CuCo2S4/RGO nanohybrid was prepared by a simple solvothermal route using Co(NO3)2,
Co(NO3)2, thiourea, and GO as precursors in EG. The polyol (such as EG) method is usually
employed to synthesize nanosized materials.17 It is known that a catalyst with amorphous or
nanocrystalline phase would be rendered a great performance on account of abundant accessible
active sites.18 In this the reaction, EG acts as a medium reductant to get RGO and also the solvent
with a chelating effect, which avoids agglomeration of NPs; GO provides large amounts of
defects/functional groups as nucleation sites for in situ growth of CuCo2S4 nanohybrids.
Thiourea is intended for the formation of sulfides of metal. The solvothermal procedure is of
significant importance, affording the crystallization of CuCo2S4 nanohybrid, the reduction of
GO, and the final formation of CuCo2S4/RGO nanohybrid.
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The crystallographic structures of CuCo2S4 and CuCo2S4/RGO nanohybrids synthesized in
EG solvent were analysed by XRD (Fig. 1). All diffraction peaks reveal the successful formation
of the carrollite structure phase of CuCo2S4. The main diffraction peaks of (022), (113), (004),
(224), (115), and (044) are attributable to carrollite phase of the CuCo2S4 structure (Fig 1a).16,19
Fig. 1b shows the XRD pattern recorded for CuCo2S4/RGO nanohybrid. The first peak located at
2Ɵ in 25 is attributable to RGO, and other diffraction peaks confirm the carrollite phase for the
CuCo2S4.
Fig. 1 XRD patterns of (a) CuCo2S4, and (b) CuCo2S4/RGO nanohybrids.
XPS was used to determine the composition of the asꢀprepared CuCo2S4/RGO nanohybrid.
Fig. 2 shows the XPS spectra of Cu 2p and Co 2p. The spinꢀorbit doublet corresponding to Cu
2p1/2 and Cu 2p3/2 is readily observed in the Cu 2p region at 952.1 and 932.0 eV with a spin–orbit
splitting value of 20.1 eV, respectively, and the Cu 2p3/2 curve region was assigned to Cu+, Cu2+
and Cu3+ (Fig. 2a).16 As shown in Fig. 2b, two prominent peaks at binding energies of 779.7 and
795.3 eV corresponded to the Co 2p3/2 and Co 2p1/2 spin–orbit peaks with a spin–orbit splitting
value of 15.6 eV, respectively, which confirmed the existence of two kinds of cobalt oxidation
state: Co2+ and Co3+.16
6

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Fig. 2 XPS curves of CuCo2S4/RGO nanohybrid (a) Cu 2p and (b) Co 2p.
Fig. 3 shows TEM images of the asꢀprepared CuCo2S4/RGO nanohybrid, that metal sulfide
NPs are uniformly decorated on graphene sheets without detachment and aggregation.
Fig. 3 (a and b) TEM images of CuCo2S4/RGO nanohybrid.
Catalytic activity
The formation of carbon–carbon bond is one of the most fundamental reactions for the
construction of molecular frameworks in organic chemistry. Therefore, in the present project, we
7

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studied the role of the prepared catalysts toward the Sonogashira coupling reaction in the
presence of the H2O solvent. The heterogeneous catalysts are used in the present project. K2CO3
was used as a base for optimizing the reaction conditions. When the reaction was tested at room
temperature, the polar solvent H2O gave an excellent yield. Therefore, in this study, we have
investigated the role of the prepared catalysts toward the Sonogashira reaction in the presence of
the H2O solvent at room temperature (Table 1).
Table 1 Sonogashira crossꢀcoupling of aryl halides with phenylacetylene catalyzed by the
CuCo2S4 and CuCo2S4/RGO nanohybrids
cat.
+
G
X
C CH
C C
G
K2CO3, H2O, r.t.
Y
Y
1a; Y = C, G = H
1b; Y = C, G = Me
1c; Y = C, G = NO2
1d; Y = N, G= H
Y = C, N
G = H, Me, NO2
X = Cl, Br, I
Entry Substrate
Product Cat.
Time (min) Yields (%)a TONb TOFb(hꢀ1)
c
CuCo2S4
35
20
55
33
93
96
85
90
46.5
240
42.5
225
79.7
720
46.4
409.1
1
2
3
4
5
6
C6H5I
1a
1a
1b
1a
CuCo2S4/RGOd
CuCo2S4
C6H5Br
CuCo2S4/RGO
CuCo2S4
CuCo2S4/RGO
CuCo2S4
CuCo2S4/RGO
CuCo2S4
190
125
155
50
115
45
67
75
65
65
70
80
70
80
33.5
187.5
32.5
162.5
35
10.6
90
4ꢀMeC6H4Br
C6H5Cl
12.6
195
18.3
266.7
3.6
4ꢀNO2C6H4Cl 1c
CuCo2S4/RGO
CuCo2S4
CuCo2S4/RGO
200
35
580
320
C5H4NCl 1d
200
37.5
b
c
aIsolated yields. See Experimental section for the calculation of TONs and TOFs. CuCo2S4 (2 mol%
of Cu). dCuCo2S4/RGO (0.4 mol% of Cu).
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The Sonogashira reaction of activated aryl iodide and bromide with different substituents
also gave good yields with yields ranging from 67 to 96%, as shown in Table 1, entries 1ꢀ3. In
addition, the yields for chlorobenzene, 1ꢀchloroꢀ4ꢀnitrobenzene and 3ꢀchloropyridine were low
with yields ranging from 65 to 80%, as shown in Table 1, entries 4ꢀ6. The results showed that the
aryl iodide and bromide are more suitable substrates for diarylacetylene synthesis.
Also, we use some other ways to improve the yield of reaction of chlorobenzene with
phenylacetylene. For this purpose, the coupling reaction of chlorobenzene with phenylacetylene
in the presence of CuCo2S4/RGO nanohybrid catalyst was tested at various solvents and
temperatures. The results are shown in Table 2. The reaction went in the presence of
CuCo2S4/RGO nanohybrid catalyst in H2O at high temperature (80 °C) and the desired product
was obtained in 73% yield (Table 2, entry 2). The solvents such as EtOH, H2O:EtOH (1:1), THF,
H2O:THF (2:1) and toluene also afforded low yields of the coupling product.
Table 2 Solvent and temperature effects on the Sonogashira reaction of chlorobenzene with
phenylacetylene catalyzed by the CuCo2S4/RGO nanohybrida
CuCo2S4/RGO
+
Cl
C CH
C C
K2CO3, solvent,
r.t. or 80 °C
Yield (%)b
Entry
Solvent
EtOH
H2O
r.t. °C
30
80 °C
43
1
2
3
4
5
6
65
42
trace
36
trace
73
59
15
52
H2O:EtOH (1:1)
THF
H2O:THF (2:1)
Toluene
trace
aReaction conditions: 0.50 mmol of chlorobenzene, 0.75 mmol of
phenylacetylene, 1.00 mmol of K2CO3, 5.0 ml of solvent, reaction time
50 min. bIsolated yield.
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Also, the Sonogashira reaction of bromobenzene with phenylacetylene in water at room
temperature was examined by Cu(NO3)2, Cu(NO3)2 + Co(NO3)2 and Cu(NO3)2 + Co(NO3)2 +
thiourea as catalyst. The results are shown in Table 3.
Table 3 Sonogashira crossꢀcoupling of bromobenzene with phenylacetylene catalyzed by the
Cu(NO3)2, Cu(NO3)2 + Co(NO3)2 and Cu(NO3)2 + Co(NO3)2 + thioureaa
cat.
+
Br
C CH
Cat.
C C
Yield (%)b
K2CO3, H2O, r.t.
Entry
1
Cu(NO3)2
Cu(NO3)2 + Co(NO3)2
Cu(NO3)2 + Co(NO3)2 + thiourea
31
2
3
37
39
a0.5 mmol of bromobenzene, 0.75 mmol of phenylacetylene, 1.00 mmol of K2CO3, 5 ml of H2O,
reaction time 55 min. bIsolated yield.
The CuCo2S4 and CuCo2S4/RGO nanohybrids are used as heterogeneous catalysts in the
present project. The results showed that Cu(NO3)2, Co(NO3)2 and thiourea act as homogeneous
catalysts, which has disadvantages of difficult product separation from reaction mixture,
recovery of catalyst and problems associated with the recycling of the catalyst. The reaction
proceeds with yields of 31%ꢀ39% in the presence of Cu(NO3)2, Cu(NO3)2 + Co(NO3)2 and
Cu(NO3)2 + Co(NO3)2 + thiourea catalysts (Table 3, entries 1ꢀ3) and with yield of 85% in the
presence of CuCo2S4 catalyst (Table 1, entry 2). The results showed that thiospinel CuCo2S4
nanohybrid is the better catalyst. Several recent studies have shown that the catalytic activity of
metals can be improved by incorporating a second metal due to the synergistic effect. Synergistic
effects were observed for the CoꢀCu catalyst.20 Transition metal based composite materials
exhibit synergistic enhancements in properties like chemical activity, stability and resistance to
10

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poisoning for catalytic activities, which are much better than a simple combination of individual
components.21 A synergistic effect of copper and cobalt was observed over the CuꢀCoꢀS
composite nanocatalyst, which showed higher activity than either Cu salt or Cu salt and Co salt
alone.
We propose that the reaction proceeds via proposed pathway in the scheme 1. Firstly,
CuCo2S4 nanohybrid in presence of K2CO3 base formed Cuꢀacetylide intermediate. Second step
of catalytic cycle is oxidative addition step and occurs between the Cuꢀacetylide complex and
carbonꢀhalogen (CꢀX) bond. The final step is the reductive elimination step where produced the
our desired diarylacetylene product and CuCo2S4 catalyst.
Scheme 1 Plausible mechanism of the CuCo2S4ꢀcatalyzed Sonogashira coupling.
Oxidative addition and reductive elimination are key steps in Sonogashira coupling reactions.
Synergistic effects could be important in reductive elimination, migratory insertion, and
nucleophilic attack on coordinated ligands,22 so, improve the catalytic activity due to the Cu–Co
interaction that accelerates the reductive elimination reaction in the last step of the reaction.
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The oxidative addition of copper into a CꢀX bond occurs in the order I > Br >> Cl >> F,
based mainly on the strength of the CꢀX bond. As expected, electronꢀwithdrawing groups on the
aryl ring enhance reactivity compared to electronꢀdonating groups. Bromobenzene is faster than
4ꢀbromotoluene in the Sonogashira reaction because CH3 is electron donor group and reduces
oxidative addition step speed, as shown in Table 1, entries 2 and 3. Chlorobenzene is slower than
1ꢀ chloroꢀ 4ꢀ nitrobenzene due to NO2 group that is electronꢀwithdrawing and cause weaken
C(sp2)ꢀCl bond and increase the speed of oxidative addition, as shown in Table 1, entries 4 and 5.
As shown in Table 1, for the reactions of aryl halides with phenylacetylene in the presence of
CuCo2S4/RGO catalyst, TOF or TON factors are higher than that for the CuCo2S4 and shorter
times are seen. The most activity of CuCo2S4/RGO is attributed to nanostructure of the catalyst
and the precense of graphene sheets that these properties increases the surface to volume ratio of
the catalyst to accelerate the reactions.
From an industrial point of view, the reusability of a catalyst is important for largeꢀscale
operation. Therefore, the reusability of the catalysts was examined in the reaction of
bromobenzene with phenylacetylene in water at room temperature. Centrifugation was applied to
separate the catalyst from the reaction mixture and then was washed with water and diethyl ether.
CuCo2S4 and CuCo2S4/RGO nanohybrids catalysts were recovered by simple filtration from the
reaction pot and can be reused successfully. The recovered catalysts were dried and checked
using XRD analysis. As shown in Fig. 4, the results showed that the catalysts can be reused
seven consecutive times without noticeably losing activity.
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Fig. 4 Recycling result of the coupling reaction of bromobenzene with phenylacetylene in the
presence of CuCo2S4 and CuCo2S4/RGO nanohybrids.
The TON and TOF is used to measure the efficiency of a catalyst. Bhaumik et al. reported that
the Sonogashira reaction over a Pd(0)/MCoSꢀ1 catalyst gives TOF of 78.3 hꢀ1.23 Sardarian et al.
reported that the Sonogashira reaction over a dendrimerꢀencapsulated Pd(0) supported on silica
catalyst gave TOF of 67.2 hꢀ1.24 In the current study using CuCo2S4/RGO as a catalyst, a higher
TOF of 720 hꢀ1 was observed for the Sonogashira reaction of iodobenzene with phenylacetylene.
We compared our results with those of the Cu metal based catalysts reported in the past few
years for Sonogashira coupling reaction, taking the reactions of bromobenzene and 4ꢀ
bromotoluene with phenylacetylene for Sonogashira coupling as two examples (Table 4).25ꢀ29
Although some of them can also obtain high yields, the following factors make our catalysts
superior to the others for these reactions. (i) excellent repeatability without loss of catalytic
activity in the H2O solvent at room temperature, (ii) the lowꢀcost Cuꢀbased catalysts were
prepared by a facile and efficient method, (iii) excellent results were obtained in short reaction
times using low catalyst loading.
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Table 4 Catalytic performance of different Cuꢀbased catalysts in the coupling of bromobenzene and 4ꢀbromotoluene with
phenylacetylene
Entry G
Catalyst
[ChCl][CuCl]a
CuIb
Solvent
DMF
DMF
DMF
dioxane
Ligand
ligandꢀfree
Lc
Base
KOH
K2CO3
Cs2CO3
Temp (ºC) Time (h)
Yield (%) Ref
1
2
3
4
5
6
7
8
H
H
H
H
H
H
H
H
140
9
80
35
91
62
57
72
85
90
32
70
51
60
67
75
25
26
27
28
29
29
140ꢀ145
135ꢀ140
110
48
15
24
CuId
DABCOe
CuIf
ethylene diamineg K2CO3
Cu(OAc)2·H2Oh solventꢀfree
DABꢀPhi
DABꢀPhl
ligandꢀfree
ligandꢀfree
DABꢀPhi
DABꢀPhl
Lc
TBABj
TBABj
K2CO3
K2CO3
TBABj
TBABj
K2CO3
130ꢀ135
140ꢀ145
r.t.
20
26
0.92
0.55
19
24
24
24
Cu(OAc)2·2H2Ok solventꢀfree
CuCo2S4
CuCo2S4/RGO
H2O
H2O
This work
This work
29
29
26
r.t.
9
Me Cu(OAc)2·H2Oh solventꢀfree
Me Cu(OAc)2·2H2Ok solventꢀfree
130ꢀ135
140ꢀ145
140ꢀ145
110
10
11
12
13
14
Me CuIb
DMF
dioxane
H2O
Me CuIf
Me CuCo2S4
Me CuCo2S4/RGO
ethylene diamineg KOH
ligandꢀfree
ligandꢀfree
28
K2CO3
K2CO3
r.t.
r.t.
3.17
2.08
This work
This work
H2O
a[ChCl][CuCl] (20 mol%), bCuI (20 mol %), cL: N,N′ꢀdibenzyl BINAM (20 mol %), dCuI (10 mol %), eDABCO (20 mol %), fCuI (30
mol %), g45 mol% ethylene diamine, hCu(OAc) 2H2O (10 mol%), iDABꢀPh: 1,4ꢀDiphenylꢀ1,4ꢀdiazabutaꢀ1,3ꢀdiene (20 mol%), jTBAB
(1 equiv). 130–135 °C. kCu(OAc)2.2H2O (50 mol%), lDABꢀPh (100 mol%).
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Conclusions
In conclusion, a simple solvothermal method was firstly used to synthesize thiospinel CuCo2S4
and CuCo2S4/RGO nanohybrids, and exhibits a high catalytic activity in the Sonogashira
coupling reaction. CuCo2S4 nanoparticles have well dispersed very small sized on GO surface,
which act as the active site for the Sonogashira reactions. Furthermore, CuCo2S4 and
CuCo2S4/RGO nanohybrids show a high catalytic activity toward aryl chloride derivatives. Our
final goal was the synthesis of nonꢀprecious metals catalysts with both improved performance
and low cost. The present method is promising for the synthesis of high performance catalysts
for Sonogashira coupling reaction.
Acknowledgements
We thank the Yasouj University Research Council and the Iranian Nanotechnology Initiative
Council for their support.
References
1 (a) L. Brandsma, S. F. Vasilevsky and H. D. Verkruijsse, Application of Transition Metal
Catalysts in Organic Synthesis; Springer: Berlin, 1988; Chapter 10, pp. 179; (b) K. C.
Nicolau and E. J. Sorensen, Classics in Total Synthesis; WileyꢀVCH: Weinheim, 1996; pp.
582.
2 (a) U. H. F. Bunz, Chem. Rev., 2000, 100, 1605; (b) D. A. Alonso, C. Najera and M. C.
Pacheco, Tetrahedron Lett., 2002, 43, 9365; (c) A. L. Rusanov, I. A. Khotina and M. M.
Begretov, Russ. Chem. Rev., 1997, 66, 1053.
15

New Journal of Chemistry
Page 16 of 21
View Article Online
DOI: 10.1039/C6NJ02771G
3 (a) G. Evano, N. Blanchard and M. Toumi, Chem. Rev., 2008, 108, 3054; (b) I. P. Beletskaya
and A. V. Cheprakov, Coord. Chem. Rev., 2004, 248, 2337; (c) F. Monnier and M. Taillefer,
Angew. Chem., Int. Ed., 2009, 48, 6954; (d) H. Rao and H. Fu, Synlett, 2011, 745; (e) H. Lin
and D. Sun, Org. Prep. Proced. Int., 2013, 45, 341; (f) D. S. Surry and S. L. Buchwald,
Chem. Sci., 2010, 1, 13; (g) E. Sperotto, G. P. M. van Klink, G. van Koten and J. G. de Vries,
Dalton Trans., 2010, 39, 10338; (h) S. V. Ley and A. W. Thomas, Angew. Chem., Int. Ed.,
2003, 42, 5400; (i) C. Sambiagio, S. P. Marsden, A. J. Blacker and P. C. McGowan, Chem.
Soc. Rev., 2014, 43, 3525; (j) Y. N. Kotovshchikov, G. V. Latyshev, N. V. Lukashev and I. P.
Org. Biomol. Chem., 2015, 13, 5542.
4 (a) K. Okuro, M. Furuune, M. Enna, M. Miura and M. Nomura, J. Org. Chem., 1993, 58,
4716; (b) K. Okuro, M. Furuune, M. Miura and M. Nomura, Tetrahedron Lett., 1992, 33,
5363; (c) A. M. Thomas, A. Sujatha and G. Anilkumar, RSC Adv., 2014, 4, 21688.
5 (a) Y. Y. Lin, Y. J. Wang, J. H. Cheng and C. F. Lee, Synlett., 2012, 930; (b) C. H. Lin, Y. J.
Wang and C. F. Lee, Eur. J. Org. Chem., 2010, 4368; (c) X. Qu, T. Li, P. Sun, Y. Zhu, H.
Yang and J. Mao, Org. Biomol. Chem., 2011, 9, 6938; (d) J. H. Li, B. X. Tang, L. M. Tao, Y.
X. Xie, Y. Liang and M. B. Zhang, J. Org. Chem., 2006, 71, 7488.
6 (a) E. Zuidema and C. Bolm, Chem. Eur. J., 2010, 16, 4181; (b) Y. Liu, J. Yang and W. Bao,
Eur. J. Org. Chem., 2009, 5317; (c) J. H. Li, J. L. Li, D. P. Wang, S. F. Pi, Y. X. Xie, M. B.
Zhang and X. C. Hu, J. Org. Chem., 2007, 72, 2053; (d) M. Wu, J. Mao, J. Guo and S. Ji,
Eur. J. Org. Chem., 2008, 4050; (e) F. Liu and D. Ma, J. Org. Chem., 2007, 72, 4844; (f) F.
Monnier, F. Turtaut, L. Duroure and M. Taillefer, Org. Lett., 2008, 10, 3203; (g) D. Ma and
F. Liu, Chem. Commun., 2004, 1934; (h) S. Priyadarshini, P. J. A. Joseph, P. Srinivas, H.
Maheswaran, M. L. Kantam and S. Bhargava, Tetrahedron Lett., 2011, 52, 1615.
16

Page 17 of 21
New Journal of Chemistry
View Article Online
DOI: 10.1039/C6NJ02771G
7 (a) G. Chen, X. Zhu, J. Cai and Y. Wan, Synth. Commun., 2007, 37, 1355; (b) D. Yang, B.
Li, H. Yang, H. Fu and L. Hu, Synlett, 2011, 702; (c) G. Chen, J. Xie, J. Weng, X. Zhu, Z.
Zheng, J. Cai and Y. Wan, Synth. Commun., 2011, 41, 3123; (d) J. T. Guan, G. A. Yu, L.
Chen, T. Q. Weng, J. J. Yuan and S. H. Liu, Appl. Organometal.Chem., 2009, 23, 75.
8 (a) C. L. Deng, Y. X. Xie, D. L. Yin and J. H. Li, Synthesis., 2006, 3370; (b) Y. X. Xie, C. L.
Deng, S. F. Pi, J. H. Li and D. L. Yin, Chin. J. Chem., 2006, 24, 1290.
9 (a) Y. Zhu, T. Li, X. Qu, P. Sun, H. Yang and J. Mao, Org. Biomol. Chem., 2011, 9, 7309;
(b) L. X. Shao and M. Shi, Tetrahedron, 2007, 63, 11938.
10 D. J. Vaughan, R. G. Burns and V. M. Burns, Geochim. Cosmochim. Acta., 1971, 35, 365.
11 (a) T. Li, H. Li, Z. Wu, H. Hao, J. Liu, T. Huang, H. Sun, J. Zhang, H. Zhang and Z. Guo,
Nanoscale, 2015, 7, 4171; (b) C. I. Pearce, R. A. D. Pattrick, D. Vaughan, J. Rev. Mineral.
Geochem., 2006, 61, 127; (c) Y. Zhang, W. Sun, X. Rui, B. Li, H. T. Tan, G. Guo, S.
Madhavi, Y. Zong and Q. Yan, Small, 2015, 11, 3694; (d) N. Mahmood, C. Zhang, J. Jiang,
F. Liu and Y. Hou, Chem. Eur. J., 2013, 19, 5183; (e) Q. Wang, L. Jiao, H. Du, Y. Si, Y.
Wang and H. Yuan, J. Mater. Chem., 2012, 22, 21387.
12 A. K. Geim and K. S. Novoselov, Nature materials., 2007, 6, 183.
13 (a) T. J. Booth, P. Blake, R. N. Rahul, D. Jiang, E. W. Hill and U. Bangert, Nano Lett., 2008,
8, 2442; (b) X. S. Du, Z. Z. Yu, A. Dasari, J. Ma, M. Mo and Y. Z. Meng, Chem. Mater.,
2008, 20, 2066; (c) D. Li, M. B. Muller, S. Gilje, R. B. Kaner and G. G. Wallace,
Nanotechnology, 2008, 3, 101.
14 (a) S. J. Hoseini, M. Dehghani and H. Nasrabadi, Catal. Sci. Technol., 2014, 4, 1078; (b) S.
J. Hoseini, V. Heidari and H. Nasrabadi, J. Mol. Catal. A: Chem., 2015, 396, 90; (c) S. J.
Hoseini, H. Ghanavat Khozestan and R. Hashemi Fath, RSC Adv., 2015, 5, 47701; (d) N.
17

New Journal of Chemistry
Page 18 of 21
View Article Online
DOI: 10.1039/C6NJ02771G
Hussain, A. Borah, G. Darabdhara, P. Gogoi, V. K. Azhagan, M. V. Shelke and M. R. Das,
New J. Chem., 2015, 39, 6631.
15 (a) W. S. Hummers and R. E. Offeman, J. Am. Chem. Soc., 1958, 80, 1339; (b) S. J. Hoseini,
M. Bahrami and M. Dehghani, RSC Adv., 2014, 4, 13796; (c) S. J. Hoseini, Z. Barzegar, M.
Bahrami, M. Roushani and M. Rashidi, J. Organomet. Chem., 2014, 769, 1.
16 J. Tang, Y. Ge, J. Shen and M. Ye, Chem. Commun., 2016, 52, 1509.
17 C. Feldmann and H. O. Jungk, Angew. Chem., Int. Ed., 2001, 40, 359.
18 (a) R. K. Hocking, R. Brimblecombe, L. Y. Chang, A. Singh, M. H. Cheah, C. Glover, W. H.
Casey and L. Spiccia, Nature Chemistry., 2011, 3, 461; (b) A. S. Arico, P. Bruce, B. Scrosati,
J. M. Tarascon and W. Van Schalkwijk, Nature materials, 2005, 4, 366.
19 D. P. Williamson and N. W Grimes, J. Phys. D: Appl. Phys., 1974, 7, 1.
20 (a) Y. Dong, L. Wu, G. Wang, H. Zhao, P. Jiang and C. Feng, Bull. Korean Chem. Soc.,
2013, 34, 3227; (b) T. Saeki, H. Ohktta, N. Kakuta and T. Mizushima, J. Ceram. Soc. Japan.,
2015, 123, 955.
21 J. Cheng, H. Yan, Y. Lu, K. Qiu, X. Hou, J. Xu, L. Han, X. Liu, J. K. Kim and Y. Luo, J.
Mater. Chem. A., 2015, 3, 9769.
22 (a) S. Shekhar and J. F. Hartwig, J. Am. Chem. Soc., 2004, 126, 13016; (b) B. Carbonnier, H.
B. Romdhane, M. Delamar, M. M. Chehimi, A. B. GonzalezꢀPerez, R. Alvarez, O. N. Faza,
A. R. de Lera and J. M. Aurrecoechea, Organometallics., 2012, 31, 2053; (c) S. J. Hoseini,
A. Zarei and H. Rafatbakhsh Iran, Appl. Organometal. Chem., 2015, 29, 489.
23 A. S. Roy, J. Mondal, B. Banerjee, P. Mondal, A. Bhaumik and S. M. Islam, Appl. Catal. A:
General., 2014, 469, 320.
24 M. Esmaeilpour, A. Sardarian and J. Javidi, Catal. Sci. Technol., 2016, 6, 4005.
18

Page 19 of 21
New Journal of Chemistry
View Article Online
DOI: 10.1039/C6NJ02771G
25 A. R. Hajipour, S. H. Nazemzadeh and F. Mohammadsaleh, Tetrahedron Lett., 2014, 55,
654.
26 K. G. Thakur, E. A. Jaseer, A. B. Naidu and G. Sekar, Tetrahedron Lett., 2009, 50, 2865.
27 J. H. Li, J. L. Li, D. P. Wang, S. F. Pi, Y. X. Xie, M. B. Zhang and X. C. Hu, J. Org. Chem.,
2007, 72, 2053.
28 Y. F. Wang, W. Deng, L. Liu and Q. X. Guo, Chin. J. Chem., 2005, 16, 1197.
29 C. L. Deng, Y. X. Xie, D. L. Yin and J. H. Li, Synthesis., 2006, 20, 3370.
19

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Figure Captions:
Fig. 1 XRD patterns of (a) CuCo2S4, and (b) CuCo2S4/RGO nanohybrids.
Fig. 2 XPS curves of CuCo2S4/RGO nanohybrid (a) Cu 2p and (b) Co 2p.
Fig. 3 (a and b) TEM images of CuCo2S4/RGO nanohybrid.
Scheme 1 Plausible mechanism of the CuCo2S4ꢀcatalyzed Sonogashira coupling.
Fig. 4 Recycling result of the coupling reaction of bromobenzene with phenylacetylene in the
presence of CuCo2S4 and CuCo2S4/RGO nanohybrids.
Table Captions:
Table 1 Sonogashira crossꢀcoupling of aryl halides with phenylacetylene catalyzed by the
CuCo2S4 and CuCo2S4/RGO nanohybrids
Table 2 Solvent and temperature effects on the Sonogashira reaction of chlorobenzene with
phenylacetylene catalyzed by the CuCo2S4/RGO nanohybrida
Table 3 Sonogashira crossꢀcoupling of bromobenzene with phenylacetylene catalyzed by the
Cu(NO3)2, Cu(NO3)2 + Co(NO3)2 and Cu(NO3)2 + Co(NO3)2 + thioureaa
Table 4 Catalytic performance of different Cuꢀbased catalysts in the coupling of bromobenzene
and 4ꢀbromotoluene with phenylacetylene
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Table of content:
Synthesis of thiospinel CuCo2S4 and CuCo2S4/ reduced-graphene oxide
nanohybrids as highly effective catalysts for the Sonogashira reaction†
Roghayeh Hashemi Fath and S. Jafar Hoseini*
Department of Chemistry, Faculty of Sciences, Yasouj University, Yasouj 7591874831, Iran
Thiospinel CuCo2S4 and CuCo2S4/ reduced-graphene oxide nanohybrids were firstly synthesized
through a simple solvothermal approach. Then, these nanohybrids are used as non-phosphine
catalysts for the Sonogashira reaction in water.
*
Corresponding author: E-mail: jhosseini@yu.ac.ir, sjhoseini54@yahoo.com, Fax: +98 74 33342172; Tel: +98 74
33223048.