Preparation and characterization of functionalized graphene oxide Cu (I) complex: A facile and reusable nanocatalyst for microwave assisted heterocyclization of alkyl halides with alkynes and sodium azide

Article abstract of DOI:10.1016/j.catcom.2016.08.034

In this research, preparation of functionalized graphene oxide copper (I) complex first involves a reaction of carboxylic groups on graphene oxide with the amino groups on 1,7-heptandiamine and isotoic anhydride, and subsequently treatment with copper iodide. The formed complex was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), energy dispersive X- ray (EDX) and field emission scanning electron microscopy (FE-SEM) techniques. 1,2,3-triazoles were synthesized from reaction of alkyl halides, alkynes and sodium azide catalyzed by functionalized graphene oxide copper (I) complex under microwave irradiation in excellent yields. This procedure eliminates the need to handle organic azides.

Full text of DOI:10.1016/j.catcom.2016.08.034

Preparation and characterization of functionalized graphene oxide Cu (I)
complex: A facile and reusable nanocatalyst for microwave assisted heterocy-
clization of alkyl halides with alkynes and sodium azide
Hossein Naeimi, Rahele Shaabani
PII:
DOI:
Reference:
S1566-7367(16)30291-6
doi: 10.1016/j.catcom.2016.08.034
CATCOM 4764
To appear in:
Catalysis Communications
Received date:
Revised date:
Accepted date:
9 July 2016
17 August 2016
19 August 2016
Please cite this article as: Hossein Naeimi, Rahele Shaabani, Preparation and character-
ization of functionalized graphene oxide Cu (I) complex: A facile and reusable nanocat-
alyst for microwave assisted heterocyclization of alkyl halides with alkynes and sodium
azide, Catalysis Communications (2016), doi: 10.1016/j.catcom.2016.08.034
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ACCEPTED MANUSCRIPT
Preparation and characterization of functionalized graphene oxide Cu (I)
complex: A facile and reusable nanocatalyst for microwave assisted
heterocyclization of alkyl halides with alkynes and sodium azide
Hossein Naeimi*, Rahele Shaabani
Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan,
8
7317-51167, I.R. Iran; Tel: 98-31-55912388; Fax: 983155912397;
E-mail: naeimi@kashanu.ac.ir
Abstract
In this research, preparation of functionalized graphene oxide copper (I) complex first
involves a reaction of carboxylic groups on graphene oxide with the amino groups on 1,7-
heptandiamine and isotoic anhydride, and subsequently treatment with copper iodide. The
formed complex was characterized by Fourier transform infrared spectroscopy (FT-IR), X-
ray diffraction spectroscopy (XRD), energy dispersive X- ray (EDX) and field emission
scanning electron microscopy (FE-SEM) techniques. 1,2,3-triazoles were synthesized from
reaction of alkyl halides, alkynes and sodium azide catalyzed by functionalized graphene
oxide copper (I) complex under microwave irradiation in excellent yields. This procedure
eliminates the need to handle organic azides.
Keywords: Gaphene oxide, 1,2,3-triazole, Heterogeneous catalyst, Microwave irradiation
Three component
Introduction
Among the various five-membered heterocyclic compounds, 1,2,3-triazoles are
important and significant due to their wide range of applications including use as
pharmaceutical agents, agrochemicals, industrial applications such as dyes, corrosion
inhibition, photostabilizers, and photographic materials [1].
Among the best-known examples of triazole-containing structures is tazobactam, a β-
lactamase inhibitor that is marketed in combination with the broad spectrum antibiotic
piperacillin. Tazobactam (I) and related triazole-containing compounds (II and III, Fig. 1)
1

ACCEPTED MANUSCRIPT
turned out to be potent β-lactamase inhibitors with higher potency than clavulanic acid and
sulbactam, and the triazole ring appears to play a pivotal role for its potency [2].
Fig. 1. Examples of triazole-containing
Numerous synthetic methods for the preparation of 1,2,3-triazole derivatives have
been developed. Among them, Cu (I)-catalyzed azide-alkyne [3] cycloaddition (CuAAC)
[
(
4,5] reaction is the most efficient way to assemble the 1,2,3-triazole ring. Generally, copper
I) salts and ligands have been used as homogeneous catalyst systems to catalyze one-pot
multi-component synthesis of 1,2,3-triazoles from benzyl/alkyl halides, alkynes and sodium
azides [6]. Homogeneous catalysis suffers from many problems such as: difficult separation
and recycling the expensive catalyst, cytotoxicity and environmental pollution. In order to
overcome these problems, it has already used many heterogeneous catalysts in the wide range
of organic reactions [7,8]. The heterogeneous catalysts offer several advantages, such as easy
recovery, easy recycling, and enhanced stability [9]. Charcoal [10], zeolites [11],
montmorillonite [12], NHC-modified silica [13], polystyrene [14] or chitosan [15] are some
of the supports used for copper (I) in the heterogeneous version of the title click reaction.
Moreover, the carbon materials have been widely used as heterogeneous catalysts. Catalysts
based on carbon materials, such as activated carbon and carbon nanotubes, have also been
studied as CuAAC catalyst supports [16].
2

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Recently, graphene, graphene oxide and graphite have attracted enormous interest in
the development of composite materials and catalysts [17-21], due to their remarkable
physical, chemical and electrical characteristics, including a very high specific surface area
[
22].
In this report, we describe a convenient and efficient advancement microwave-
accelerated of one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles from in-situ-generated
azides, terminal alkynes and functionalized graphene oxide copper (I) complex as an efficient
recyclable catalyst.
Experimental
General procedure for the synthesis of GO-NH-IA-Cu (I) complex
Graphene oxide was prepared using a modification of Hummers and Offeman’s
method [23].
Typically, GO (0.5 g) was suspended in SOCl (30 mL) and 10 mL of DMF was
2
o
added and subsequently, the reaction mixture was refluxed at 70 C for 24 h. The resultant
solution was filtered and washed with anhydrous tetrahydrofuran (THF) and dried under
vacuum, the GO-COCl was obtained.
In the next step of catalyst preparation, GO–COCl (0.4 g) was suspended in 1,7-
heptandiamine and 25 mL DMF was added and subsequently, the reaction mixture was
o
refluxed at 70 C for 24 h. The resultant solution was filtered and washed with ethanol to
ensure that the excess diamine was completely removed. Finally, the products were dried at
o
7
0 C under vacuum.
In continuation, GO-CO-NH (0.36 g) and isotoic anhydride (0.36 g) was suspended
2
o
in 30 mL ethanol was added and subsequently, the reaction mixture was at refluxed 60 C for
2
4 h. The resultant solution was filtered and washed with ethanol to ensure that the excess
3

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o
isotoic anhydride was completely removed. Finally, the products were dried at 70 C under
vacuum.
In the final of catalyst preparation, GO-CO-NH-IA (0.35 g) and copper iodide (0.35
g) was suspended in 30 mL acetonitrile was added and subsequently, the reaction mixture
o
was at refluxed at 60 C for 18 h. The resultant solution was filtered and washed with
acetonitrile to ensure that the excess copper iodide was completely removed. Finally, the
o
products were dried at 70 C under vacuum, the pure complex was obtained.
For synthesis of 1,2,3-triazoles, alkyne (1mmol), alkyl halide (1 mmol) and NaN (1.2
3
mmol) followed by adding GO-NH-IA-Cu(I) as catalyst in a 10.0 mL round-bottomed flask
(
H O-Ethanol, 6.0 mL). The mixture was treated under microwave irradiation (MW, 100 W).
2
The progress of the reaction was monitored by TLC. After completion of the reaction, the
catalyst was isolated by filtration through celite and the product was extracted with EtOAc (3
1
13
×
10 mL). The products were characterized by H NMR, C NMR, FT-IR and melting points
and the spectral data of synthesized compounds were compared with authentic samples and
confirmed [24-30].
o
1
1
1
-Benzyl-4-phenyl-1H-1,2,3-triazole (Table 4, 3a); White solid, m.p = 125-127 C (Lit. [24].
o
-1
28-130 C); IR (KBr) ν (cm ): 3139 (C=C-H), 2924 (-C-H), 1607 (C=C), 1456, 1353 (C-N),
1
218, 1073, 1046; H NMR (CDCl , 400 MHz) δ (ppm): 5.58 (s, 2H, CH ), 7.32 (m, 3H,
3
2
Haromatic), 7.40 (m, 5H, Haromatic), 7.67 (s, 1H, Htriazole), 7.80-7.82 (d, J=8.0 Hz, 2H, Haromatic);
1
3
C NMR (CDCl , 100 MHz) δ (ppm): 54.21, 119.57, 125.71, 128.06, 128.17, 128.78,
3
1
28.82, 129.16, 130.58, 134.74, 148.22.
Results and discussion
In order to prepare the catalyst, at first graphene oxide was prepared according to the
modified Hummer's method. The obtained GO was treated with thionyl chloride in DMF at
4

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reflux temperature for 24 hours to generate GO–COCl and subsequently reacted with 1,7-
heptandiamin to yield amino-modified graphene oxide (GO-CO-NH ). The obtained amino-
2
modified graphene oxide was then treated with isotoic anhydride in ethanol at reflux
temperature for 24 hours to generate (GO-CO-NH-IA). Finally, the GO-CO-NH-IA was
treated with CuI in acetonitrile at reflux temperature for 18 hours. The catalyst was
characterized using various techniques.
Fig. 2 shows the FT-IR spectra of GO, GO–COCl, GO-NH , GO-NH-IA. In the FT-IR
2
-1
spectrum of GO, the peaks at 3349, 1719, 1580 and 1064 cm correspond to the O–H, C=O,
C=C and C–O stretching vibration, respectively. In the FT-IR spectrum of GO–COCl (Figure
-1
4
b), the relative intensity of the C=O stretch of the –COOH group at 1730 cm has
significantly decreased, that confirmed the most carboxyl group functionalities have been
transformed into the acyl chloride.
Fig. 2. FT-IR spectra of a) GO, b) GO-CO-Cl, c) GO-NH and d) GO-NH-IA
2
5

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To optimize the reaction conditions for the formation of 1,4-disubstituted 1,2,3-
triazoles from alkyl halide, alkyne and sodium azide, we devoted our efforts on this research
using the reaction of phenylacetylene, benzyl chloride and NaN in the catalytic amount of
3
GO-NH-IA-Cu (I) as a simple reaction. The reaction was carried out in the presence of
different quantities of the catalyst in water-ethanol (Table 1). It was found that the best result
was obtained when the reaction was carried out in the presence of 0.005 g of catalyst (Table
1
, entry 3). The usage of higher amounts of catalyst did not increase the yields significantly.
Table 1. Optimization of catalyst for synthesis of 1,2,3-triazole
a
Entry
Catalyst (g)
0
Time (min)
Yield (%)
1
2
3
4
120
15
0
0.002
0.005
0.01
85
88
88
88
10
12
5
0.015
14
a
Isolated yields
Reaction conditions: 1 mmol phenylacetylene, 1 mmol benzyl chloride, 1.2 mmol NaN (0.005)
3
o
catalyst were added to the selected solvent (6 mL) under 100 W microwave irradiation at 80 C
temperature
In order to verify the effect of solvent, the model reaction was carried out in the
presence of different solvents. The corresponding results are shown in Table 2. The best
solvent was mixture of water and ethanol (1:1), which was resulted in higher yield and
shorter reaction time in compared to the other used solvents (Table 2, entry 4).
Table 2. Effect of various solvent on synthesis of 1,2,3-triazole
a
Entry
Solvent
Time (min)
Yield (%)
1
2
3
CH CN
20
18
15
50
60
72
3
H O-CH CN(1:1)
2
3
H O-Acetone(1:1)
2
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4
5
6
7
8
H O-EtOH(1:1)
7
88
80
83
82
65
2
H O-EtOH(2:1)
2
10
8
H O-EtOH(1:2)
2
EtOH
10
12
H O
2
Reaction conditions: 1 mmol phenylacetylene, 1 mmol benzyl chloride, 1.2 mmol NaN , and (0.005 gr)
3
o
GO-NH-IA-Cu (I) were added to the selected solvent (6 mL) under 100 W microwave irradiation at 80 C
temperature
a
Isolated yields
We further examined the effect of microwave power, and the irradiation time (Table 3) on the
click reaction involving of phenylacetylene, benzyl chloride and NaN in the catalytic amount
3
of GO-NH-IA-Cu (I) under various powers of microwave irradiation (Table 3, entry 2).When
higher powers are used degradation product is occurred that it lead to the decrease in product
yields.
Table 3. Effect of microwave irradiation on synthesis of 1,2,3-triazole
a
Entry
Power (W)
Time (min)
Yield (%)
1
2
3
4
-
180
10
0
100
180
300
88
84
80
12
15
Reaction conditions: 1 mmol phenylacetylene, 1 mmol benzyl chloride, 1.2 mmol NaN , and (0.005
3
gr) GO-NH-IA-Cu (I) were added to the 1:1 mixture solvent of EtOH:H O as solvent (6 mL) under
2
various microwave irradiation power.
a
Isolated yields
After optimization of the reaction conditions, this three-component reaction proceeds
via in-situ formation of an alkyl azide from an alkyl halide and sodium azide. The alkyl azide
then undergoes 1,3-dipolarcycloaddition reaction with terminal alkynes to give 1,4-
disubstituted 1,2,3-triazoles in high to excellent yields. Here, we describe a process in which
GO-NH-IA-Cu (I) efficiently catalyzes azide–alkyne cycloaddition under microwave
irradiation (Table 4).
7

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Table 4. The GO-NH-IA-Cu (I) catalyzed three component synthesis of triazoles
N
Br
N
N
N
N
N
N
N
N
Cl
3b, 12 min, 87
3c, 14 min, 86
3
a,10 min, 88
F
N
N
O N
2
N
N
N
N
N
N
N
Cl
NO2
Cl 3d, 14 min, 84
3e, 15 min, 82
3
f, 18 min, 81
Br
N
N
N
N
N
N
N
CH3
CH3
N
N
3i, 15 min, 83
3g, 12 min, 90
3h, 13 min, 81
N
N
N
O N
2
O N
2
N
N
N
N
N
CH3
N
3
l, 25 min, 75
3k, 12 min, 86
3j, 14 min, 87
N
N
N
3m, 10 min, 80
In order to development and limitations of the general protocol, it was investigated the
reaction using a variety of benzyl and alkyl halides and alkynes as the substrates under the
same conditions. The related results are summarized in Table 4. As can be seen in this Table,
the products were obtained in high to excellent yields and short reaction times for all of the
entries.
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We further explored the reusability of the catalyst in the model reaction with
treatment of the benzyl chloride, the phenylacetylene, NaN in the presence of 0.005 g of
3
GO-NH-IA-Cu(I) catalyst under microwave irradiation (Figure 3). As can be seen from this
figure, the catalyst can be used up to six cycles with slight decrease in the yield percentage. It
also was observed that the catalyst showed excellent activity for the cycloaddition reaction
even after the sixth cycle.
100
80
60
40
20
1
2
3
4
5
6
Run
Fig. 3. Reusability of catalyst for synthesis of 1,4-disubstituted 1,2,3-triazoles
In the present work, we developed a new functionalized graphene oxide copper (I)
complex as a heterogeneous catalyst in click reaction. It shows high catalytic activity for
synthesis of triazoles under microwave irradiation. This efficient procedure can be applied to
the synthesis of a wide variety of 1,2,3-triazoles in high to excellent yields. The advantages of
catalyst are inexpensive nature, reusability and stability of the catalyst, simplicity of
procedure and work up and green condition.
9

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Acknowledgments
The authors are grateful to the University of Kashan for supporting this work by grant no.
59148/68.
1
References
1] H. Dehne, in: Methoden der Organischen Chemie (Houben-Weyl), (Ed.: E. Schumann,),
Thieme, Stuttgart, 1994, Vol. E 8d, pp 305–405.
[
[
(
[
2] S.Yan, Y. Liu, Y. Chen, L. Liu, J. Lin, Bioorganic and Medicinal Chemistry Letters, 20
2010) 5225–5228.
3] X. Zhang, H. Li, L. You, Y. Tang, R. P. Hsung, Adv. Synth. Catal. 348 (2006) 2437–
2
442.
4] V.V. Rostovtsev, L.G. Green, V.V. Fokin, K.B. Sharpless, Angew. Chem. 114 (2002)
708–2711.
5] L.D. Pachon, J.H. van Maarseveen, G. Rothenberg, Adv. Synth. Catal. 347 (2005) 811–
15.
[
2
[
8
[
[
[
6] X.Q., Xiong, L., Cai, Z.K., Tang, Chin. J. Org. Chem. 32 (2012)1410–1428.
7] H. Naeimi, Z.S. Nazifi, Appl. Catal. 477 (2014) 132–140
8] R. Ghahremanzadeh, Z. Rashid, A.-H. Zarnani, H. Naeimi,Appl. Catal. 467 (2013) 270–
2
78.
[
[
[
9] K. Kaneda, K. Ebitani, T. Mizugaki, K. Mori, Bull. Chem. Soc. Jpn. 79 (2006) 981–1016.
10] C.-T. Lee, S. Huang, B.H. Lipshutz, Adv. Synth. Catal. 357 (2009) 3139−3142.
11] S. Chassaing, A. Alix, T. Boningari, K.S.S. Sido, M. Keller, P. Kuhn, B. Louis, J.
Sommer, P. Pale, Synthesis 9 (2010) 1557–1567.
[
12] I. Jlalia, H. Elamari, F. Meganem, J. Herscovici, C. Girard, Tetrahedron Lett. 49 (2008)
6
756−6758.
[
[
13] P. Li, L. Wang, Y. Zhang, Tetrahedron 64 (2008)10825−10830.
14] U. Sirion, Y.J. Bae, B.S. Lee, D.A. Chi, Synlett.15 (2008) 2326–2330.
[
15] M. Chtchcigrovsky, A. Primo, P. Gonzalez, K. Molvinger, M. Robitzer, F. Quignard, F.
Taran, Angew. Chem. 121 (2009) 6030−6034
[
16] H. Sharghi, M.H. Beyzavi, A. Safavi, M.M. Doroodmand, R. Khalifeh, Adv. Synth.
Catal. 351 (2009) 2391–2410.
[
[
17] M. Fang, K. Wang, H. Lu, Y. Yang, S. Nutt, J. Mater. Chem. 19 (2009) 7098-7105.
18] D.R. Dreyer, C.W. Bielawski, Chem. Sci. 2 (2011) 1233-1240.
1
0

ACCEPTED MANUSCRIPT
[
(
[
[
[
[
[
19] Y.-F. Li, M.-Q. Guo, S.-F. Yin, L. Chen, Y.-B. Zhou, R.-H. Qiu, C.-T. Au, Carbon, 55
2013) 269-275.
20] D.-H. Lan, F.-M. Yang, S.-L. Luo, C.-T Au, S.-F. Yin, Carbon, 73 (2014) 351-360.
21] D.-H. Lan, L. Chen, C.-T. Au, S.-F. Yin, Carbon, 93 (2015) 22-31.
22] M.J. Allen, V.C. Tung, R.B. Kaner, Chem. Rev. 110 (2010) 132-145.
23] W.S. Hummers, R.E. Offeman, J. Am. Chem. Soc. 80 (1958) 1339-1339.
24] S. Chassaing, A. Sani Souna Sido, A. Alix, M. Kumarraja, P. Pale, J. Sommer, Chem-
Eur J. 14 (2008) 6713-6721.
[
(
[
[
[
[
25] S.T. Abu-Orabi, M.A. Atfah, I. Jibril, F.M. Marii, A.A.-S. Ali, J. Heterocyclic, Chem. 26
1989) 1461-1468.
26] S.B. Otvos, I.M. Mandity, L. Kiss, F. Fulop, Chem–Asian J.8 (2013) 800-808.
27] H. Naeimi, S. Dadashzadeh, M. Moradian, Res. Chem. Intermed. 5(2015) 2687-2695.
28] Z. Gonda, Z. Novak, Dalton Trans. 39 (2010) 726-729.
29] P. Appukkuttan, W. Dehaen, V.V. Fokin, E. van der Eycken, Org. Lett. 6 (2004) 4223-
4
225.
30] T. Jin, M. Yan, Menggenbateer, T. Minato, M. Bao, Y. Yamamoto, Adv. Synth. Catal.
53 (2011) 3095-3100.
[
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Graphical abstract
1
2

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Highlight
•
•
•
•
•
Developed a new functionalized graphene oxide copper (I) complex.
Recoverable heterogeneous catalyst.
High activity of the catalyst in the synthesis of 1,2,3-triazoles.
Easy work-up of pure target products.
Excellent product yields and Short reaction times.
1
3