Synthesis and characterization of a novel polyoxometalate-Cu(II) hybrid catalyst for efficient synthesis of triazols

Article abstract of DOI:10.1016/j.poly.2016.02.003

A new hybrid complex based on covalent interaction between 1,2-bis(p-aminophenylthio)ethane, (BAPTE), and a Lindqvist type polyoxometalate, Mo₆O₁₉^2-, was prepared. This new hybrid catalyst, Cu^II(BAPTE)Cl₂

Full text of DOI:10.1016/j.poly.2016.02.003

Accepted Manuscript
Synthesis and characterization of a novel polyoxometalate–Cu(II) hybrid cata-
lyst for efficient synthesis of triazols
Ali Zarnegaryan, Majid Moghadam, Shahram Tangestaninejad, Valiollah
Mirkhani, Iraj Mohammadpoor−Baltork
PII:
S0277-5387(16)00086-3
DOI:
http://dx.doi.org/10.1016/j.poly.2016.02.003
POLY 11816
Reference:
Polyhedron
To appear in:
Received Date:
Accepted Date:
26 December 2015
5 February 2016
Please cite this article as: A. Zarnegaryan, M. Moghadam, S. Tangestaninejad, V. Mirkhani, I. Mohammadpoor
−Baltork, Synthesis and characterization of a novel polyoxometalate–Cu(II) hybrid catalyst for efficient synthesis
of triazols, Polyhedron (2016), doi: http://dx.doi.org/10.1016/j.poly.2016.02.003
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Synthesis and characterization of a novel polyoxometalate–Cu(II)
hybrid catalyst for efficient synthesis of triazols
Ali Zarnegaryan, Majid Moghadam,* Shahram Tangestaninejad, * Valiollah Mirkhani,* Iraj
Mohammadpoor−Baltork
Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746−73441, Iran
Abstract−
A
new hybrid complex based on covalent interaction between
2−
,
1,2−bis(p−aminophenylthio)− ethane, (BAPTE), and a Lindqvist type polyoxometalate, Mo6O19
was prepared. This new hybrid catalyst, CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2, was characterized
1
by H NMR, FT− IR, and UV−vis spectroscopic methods and cyclic voltammetry. The catalytic
activity of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 hybrid material was investigated in the three
component reaction of sodium azide, phenylacetylene and benzyl halides and the corresponding
triazoles were produced in good to excellent yield. The reusability of this catalyst was also
investigated.
Keywords. Polyoxometalate; Inorganic–organic compound; Click reaction; Hybrid copper(II)
catalyst.
1. Introduction
Polyoxometalate (POM) anions represent an important class of nanosized polynuclear clusters
consisting of d−block transition metals and oxygen atoms. The tunability of their size, structure and
elemental composition, and hence of their chemical and electronic properties, render them
*Corresponding authors: Tel: +98-31-37934920; Fax: +98-31-36689732; E-mails: moghadamm@sci.ui.ac.ir (M.
Moghadam); stanges@sci.ui.ac.ir (S. Tangestaninejad); mirkhani@sci.ui.ac.ir (V. Mirkhani).
1

particularly interesting both for fundamental and applied science, especially for catalysis, materials
science and medicine [1−5].
Modification of POMs is very important for their subsequent research and application. An effective
way to achieve this goal is to modify the POMs with organic materials to obtain organic‒inorganic
hybrids. Organic components can dramatically influence the microstructure of hybrid materials. In
addition, the synergic interactions between organic and inorganic components may be exploited in
the preparation, which make hybrid materials exhibit composite properties [6]. Thus, construction
of such hybrid materials involves the selection and design of organic and inorganic building units as
well as the control of synergic interactions between the counterparts [7, 8].
Lindqvist hexamolybdate cluster, [Mo6O19]2− (Fig. 1), as a unique class of metal oxide clusters, is an
ideal building block for constructing the organic–inorganic hybrid assemblies [9−11].
Two coordination approaches for the assembly of POMs into macrostructures are as following: (i)
Transition metal−substituted POMs are chosen as subunits and organic ligands as intermolecular
linkers through coordinating with transition metal ions [12, 13]. (ii) Preformed organic derivatives
of POMs, that is POM−functionalized organic ligands, are utilized as building blocks, and transition
metal ions as linkers via a well−defined coordination mode [14−18].
Copper(II) containing complexes have been widely used as linking units for construction of hybrid
compounds due to their relatively strong coordination abilities with both S and N donor atoms of
organic ligands, as well as due to their capacity to adopt various coordination numbers [19].
The copper−catalyzed azide−alkyne cycloaddition (CuAAC) has received much attention in recent
years [20−24]. In this reaction, a terminal azide is co pled with an alkyne to produce 1, 2,3−triazoles
via a [3+2] Huisgen cycloaddition. This reaction is an excellent example of “click” chemistry
because of its selectivity and tolerance to a variety of reaction conditions. It is well known that the
best catalyst for this reaction is Cu (I) species [25,26]. The most advantages of these copper
catalyzed reactions are wide−ranging scope, using readily available reagents, and insensitivity to
2

oxygen and water [27−30]. Recent studies have shown that highly efficient reactions generically
known as “click” reactions provide a versatile route toward highly functional surfaces [31−33].
In recent years, we reported the application of different hybrid materials in catalysis. The [MoO2
(N,N
(salicylidene)ethylenediamine)−K8(SiW11O39)], [nickel(N,N
(SiW11O39)] and [cobalt(N,N−bis(salicylidene)ethylenediamine)−K8(SiW11O39)] systems have been
́
́−
́
́
studied in the oxidation of olefins or benzyl halides [14−18]. Recently, we prepared
metalloporphyrins–polyoxometalate hybrid compounds and investigated their catalytic activity in
the in the epoxidation of alkenes and acetylation of alcohols and phenols [34, 35].
The goal of this research was to prepare a new hybrid material based on the covalent attachment of
2−
Lindqvist Mo6O19 to copper complex of 1,2−bis(p−aminophenythio)ethane, BAPTE. This new
heterogeneous catalyst, CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2, was applied in the synthesis of
1,2,3−triazoles by the reaction of phenylacetylenes with benzyl halides in the presence of sodium
azide (Scheme 1).
2. Experimental
All chemicals were used as received from the suppliers. Solvents were used as received or distilled
and dried using the standard procedures. Tetrabutylammonium hexamolybdate,
[(n−C4H9)4N]2[Mo6O19] was prepared according to the literature method [36].The ligand,
1,2−bis(p−aminophenylthio)ethane (BAPTE) was synthesized according to a reported procedure
1
[37].All the synthetic procedures were performed protected from light. H NMR spectra were
recorded on a Bruker−Avance AQS 400 MHz NMR spectrometer using DMSO as solvent.
Elemental analyses were measured by a Perkin Elmer 2400 instrument. The amount of Mo was
measured by a Leaman inductively coupled plasma (ICP) spectrometer. Atomic absorption analysis
was carried out on a Shimadzu 120 spectrophotometer. The electronic spectra of the compounds in
the UV−vis region were recorded in DMF solution using a Shimadzu 160 UV−vis or a Varian Cary
NIR spectrophotometer. FT−IR spectra were obtained as potassium bromide pellets in the range
3

400–4000 cm−1 with a Jasco 6300D instrument. Redox potentials of the compounds (10−3 molL−1)
in DMF containing tetrabutylammonium bromide (TBAB, 0.1 molL−1) as a supporting electrolyte
were determined at room temperature by cyclic voltammetry with a PGSTAT30 (Eco Chemie,
Utrecht, The Netherlands) electrochemical analyzer. A three−electrode cell was used, including
glassy carbon electrode as working electrode, together with an Ag/AgCl (saturated KCl) and a
platinum wire as reference and counter electrode, respectively.
2.1. Synthesis of 1,2−bis(p−aminophenylthio)ethane, BAPTE
In a round−bottom flask, 4−aminothiophenol (2.5 g, 20 mmol) was added to absolute EtOH (20 ml)
containing Na (0.46 g, 20 mmol). Then, 1,2−dibromoethane (0.86 ml, 10 mmol) in EtOH (5 ml)
was added dropwise with constant stirring to the refluxing solution. The mixture was cooled and
poured into H2O (300 ml). The solid was filtered off, washed with H2O and dried. The product was
º
recrystallized from EtOH, and a yellowish residue was obtained. Yield: 68%, m.p. 79 C. 1H NMR
(400 MHz, CDCl3): δ = 7.19 (2H, d), 7.21 (2H, m), 6.60 (2H, m), 6.62 (2H, d), 3.73 (4H, m), 2.89
(4H, m). FT−IR (KBr) (cm−1): 3416(s), 2932 (w), 2280 (w), 1630 (w), 1592 (m), 1493(s), 1283 (s),
1176 (m), 1117 (m), 819 (s).
2.2. Synthesis (BAPTE)−[n−Bu4N]4[Mo6O18]2
In a round−bottom flask, BAPTE (69 mg, 0.25 mmol), [(n−C4H9)4N]2[Mo6O19] (690 mg, 0.50
mmol) and N,N′−dicyclohexylcarbodiimide (DCC, 0.15 g, 0.72 mmol) were dissolved in anhydrous
DMSO (10 mL) and heated at 100 °C under a dry atmosphere for 8 h. The reaction was cooled to
room temperature and filtered under vacuum (to remove the dicyclohexylcarbodiurea) into a flask
containing dry ether (100 mL) and dry methanol (20 mL). A precipitate was formed and washed
1
several times with acetone and ether. Yield: %57, H NMR (400 MHz, DMSO−d6): δ=7.19 [d, 4H,
protons aromatic], 6.60 [d, 4H, protons aromatic], 3.32 [t, 32 H, (CH3CH2CH2CH2N)], 3.01 [s, 4H,
SCH2CH2S], 1.57 [m, 32H, (CH3CH2CH2CH2N)], 1.31 [q, 32H, (CH3CH2CH2CH2N)], 0.94 [t, 48H,
(CH3CH2CH2CH2N)]; IR (cm–1): 710 (C–C), 783 (Mo–O–Mo), 947 (Mo–O), 984 (Mo–N), 1148
(C–S), 1384 (C–N) 1490, 1642 (C=C), 2881, 2952, 3001 (C–H); 3092, 30123 (Ar–H); UV−vis
4

spectrum (in DMF): (λmax= 396 nm). Elemental Anal. calcd for Mo12O36C78H156N6S2: C, 31.54; H,
5.23; N, 2.85; S, 2.19. Found: C, 31.63; H, 5.16; N, 2.73; S, 2.11.
2.3. Synthesis of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2
In a round−bottom flask, (BAPTE)−[n−Bu4N]4[Mo6O18]2 (0.38 g, 0.13 mmol) and CuCl2.2H2O
(0.02 g, 0.13 mmol) were dissolved in anhydrous DMF (10 mL) and heated to 100 °C under a dry
atmosphere for 6 h. The reaction was cooled to room temperature and filtered under vacuum into a
flask containing dry ether (100 mL) and dry methanol (20 mL). A precipitate was formed and
washed several times with acetone and ether. The dried product was stored in a desiccator.
Yield: %53, IR (cm–1): 448–472 (Cu–S), 708 (C–C), 781 (Mo–O–Mo), 946 (Mo–O), 982 (Mo–N),
1146 (C–S), 1382 (C–N), 1489, 1640 (C=C), 2880, 2950, 3000 (C–H); 3090, 30120 (Ar–H).
Elemental Anal. calcd for Mo12O36C78H156N6S2 CuCl2: C, 30.24; H, 5.06; N, 2.75; S, 2.09. Found:
C, 30.13; H, 5.03; N, 2.67; S, 2.02.
2.4. General procedure for synthesis of 1,2,3−triazoles
A mixture of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 (1%, 30 mg) in H2O/DMSO (3 mL, 1:10) was
stirred for 10 min. Then, the phenylacetylenes (1.3 mmol), benzyl halide (1 mmol), sodium azide
(1.1 mmol) and sodium ascorbate (5 mol%) were added, and the resulting mixture was stirred at
room temperature. The progress of the reaction was monitored by TLC (eluting with
n−hexane/ethyl acetate, 1:1). At the end of the reaction, methanol (5 mL) was added to precipitate
the catalyst. The catalyst was recovered by centrifugation, washed with methanol and diethyl ether,
and dried in vaccuo. The filtrates were concentrated and the pure product was obtained by thin layer
chromatography.
3. Results and discussion
3.1. Preparation and characterization of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2
Usually, the association of a molecular unit to a POM is attained by electrostatic interaction [38].
However, in order to increase the stability of the hybrid material, especially in polar solvents; a
covalent linkage was established between POM and dithiol ligand. The reaction between POM and
5

the amines of the ligand was carried out according to the procedure reported for the attachment of
hexamolybdate to aromatic amines in the presence of dicyclohexylcarbodiimide (DCC) [39]. Direct
−
2
coupling of Mo6O19 with BAPTE ligand in the presence of triethylamine was unsuccessful [40],
but good results were obtained using DCC as coupling agent. The synthetic route for
CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 is demonstrated in Scheme 2.
First, 4−aminothiophenol was reacted with 1,2−dibromoethane to produce BAPTE. Next, this
ligand was hybridized with. tetrbutylammonium hexamolybdate in the presence of DCC and
(BAPTE)−[n−Bu4N]4[Mo6O18]2 was prepared. Finally, (BAPTE)−[n−Bu4N]4[Mo6O18]2 was reacted
with CuCl2.2H2O for preparation of hybrid compound.
The hybrid compound is soluble in polar, aprotic solvents such as DMSO and DMF. Several
attempts for preparation of single crystals of this hybrid compounds were unsuccessful. Therefore,
this new hybrid material was characterized by FT−IR, UV−vis and 1H NMR spectroscopic methods,
and cyclic voltammetric studies. All these techniques provide more details for characterization of
this polyoxometalate–copper complex hybrid material.
The FT−IR spectra of ligand and hybrid material are shown in Fig 2. The Lindqvist structure shows
characteristic IR bands in the 700–1000 cm−1 region assigned to M–O and M–O–M stretching
vibrations. The hybrid compound displays similar characteristic bands of the Lindqvist structure.
Compared to the parent hexamolybdate anion, the asymmetric Mo–Ob–Mo stretching vibration is
bathochromically shifted respectively from 797 to 781 cm−1 for hybrid compound. These
observations imply that these bonds are weakened to some extent due to the stronger Mo–N
bonding interaction than that of Mo–O. In the case of hexamolybdate hybrid compounds, the Mo–O
vibration is split into two or more bands as commonly observed in arylimido derivatives of
hexamolybdate [39]. In this study, the Mo–O band at 957 cm−1 splits to three bands at 946, 933 and
915 cm−1. Such splitting has been ascribed to the reduction in symmetry of the hexamolybdate
framework from Oh to C4v upon the substitution of MotO by MotNAr. The less intense band, a
shoulder at 982 cm−1, might associate principally with the Mo−N vibration. The vibrational bands at
6

around 2900 cm−1 are assigned to the stretching vibrations of the methyl and methylene groups in
the tetrabutylammonium cations. The bands at 1382 and 1146 can be attributed to the υ(C–N) of the
arylimido group and ν(C–S), respectively. Upon attachment of Cu to the
(BAPTE)−[n−Bu4N]4[Mo6O18]2, a band was appeared in the range of 448–472 cm−1 due to νas(Cu–
S) vibration.
1
The H NMR spectra of BAPTE and (BAPTE)−[n−Bu4N]4[Mo6O18]2 hybrid compound are shown
in Fig. 3. These spectra clearly show resolved signals that can be unambiguously assigned. The
signals correspond to the aromatic protons present at 6.60–7.21 ppm for BAPTE. In addition, the
well−resolved signal at 3.73 ppm is attributed to the NH2 protons of the ligand (Fig. 3A). Upon
hybridization of ligand organic with hexamolybdate, all these signals exhibited downfield chemical
shifts compared to the parent BAPTE. This can be attributed to the shielding effect of the POM
cluster which is weaker than that of the amino group. This is due to the electron−withdrawing
nature of the hexamolybdate moiety. In the (BAPTE)−[n−Bu4N]4[Mo6O18]2 hybrid compound, the
aromatic protons signals present at 7.21 and 7.09 ppm and the signal corresponding to the –NH2
protons was disappeared in the hybrid compound.
The electronic properties of the POM, BAPTE, (BAPTE)−[n−Bu4N]4[Mo6O18]2 and hybrid
compound were also studied by UV−vis spectrophotometry (see Fig. S1−S4). The maximum
absorption wavelength of the parent hexamolybdate is 325 nm, which is derived from the
charge−transfer transition from the oxygen π−type HOMO to the molybdenum d−type LUMO. The
strong band at 396 nm originates from the charge−transfer transition of the coordinated N atom to
the molybdenum atom (LMCT) [41, 42]. The weak absorption peak in the UV−vis spectrum of
CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 at 620 nm is attributed to the d−d transitions of the Cu(II)
which is a good indication of complexation of hybrid compound.
The electrochemical properties of the BAPTE, POM and CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2
were studied in degassed DMF containing tetrabutylammonium bromide (TBAB) (0.1 mol L−1) as
supporting electrolyte. All potentials are quoted relative to an Ag/AgCl (saturated KCl) electrode
7

[43]. The cyclic voltammogram (see Fig. S5–S7) of the hybrid compound showed a reduction wave
(II) at −1.35 V. This remarkable cathodic shift in the reduction potential of this compound may be
associated to the more difficult reduction of the polyoxometalate due to the electron–donating
properties of the ring ligand toward the polyoxometalate. This is a similar behavior which has been
reported in the attachment of 2, 2′–bipyridine (bipy) and 1,10–phenanthroline to hexamolybdate
[44, 45]. One couple of redox peaks (I–I′) located at Ep= –0.75 V and E = –0.88 V is observed.
p
These peaks correspond to reduction steps involving Mo atoms, which are similar to analogous
compounds reported in the literature [46]. The CV of the parent hybrid compound showed a shift to
positive potentials upon attachment of polyoxometalate. This can be attributed to the relatively
facile reduction of the copper complex of 1,2−bis(p−aminophenythio)ethane moiety due to the very
strong electron–withdrawing effect of the polyoxometalate. However, the oxidation peak of copper
centers is not observed for hybrid compound, perhaps due to their weak signals embedded in the
redox peaks of Mo [47–51].
3.2. Catalytic studies
CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 was used as catalyst in synthesis of triazoles. Initially, for
screening experiments, the three−component reaction between phenylacetylene (1 mmol),
4−bromobenzyl bromide (1 mmol), and sodium azide (1.1 mmol) in H2O/DMSO (1:10) was chosen
as a model reaction (Table 1). In the absence of catalyst no appreciable amount of product was
produced (Table 1, entry 1). The presence sodium ascorbate is necessary for reduction of CuII to CuI
species. In the absence of sodium ascorbate only 10% of the corresponding triazole was produced
(entry 2). While in the presence of sodium ascorbate and 1 mol% (30 mg) of
CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2, the highest yield was obtained (entry 4). As mentioned in
the literature, the in the synthesis of unhybridized complex using PhSCH2CH2SPh or p-H2N-
PhSCH2CH2SPh-NH2 as ligand, polymeric materials were produced [52]. Therefore, to show the
effect of hybridization on the catalytic activity of CuII (BAPTE), we refer to our recently published
papers in the click reaction. In these two papers, we used a very similar ligand, 1,2-bis(4-
8

pyridylthio)ethane, immobilized on polystyrene and silica nanoparticles. The copper chloro
complex was inactive in these reactions. Therefore, the chlorides were exchanged with OTf anions
to increase the electron deficiency of copper center [53, 54]. But upon hybridization with POM, the
catalytic activity of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 increases. This can be attributed to the
increasing the electron−deficiency of POM on the CuII(BAPTE). This shows the synergistic effect
of hexamolybdate on the catalytic activity of CuII (BAPTE) Cl2. The reaction was also performed in
H2O or DMSO and the results were less than using H2O/DMSO (1:10) as reaction media (entries 6
and 7). The catalyst is soluble in this media and acts as a homogeneous catalyst in the click reaction.
The CuCl2 salt was less efficient in this reaction (entry 8). On the other hand, the catalytic activity
of hexamolybdate (1 mmol) was also investigated in the model reaction. The results showed that the
amount of the produced triazole was as same as blank experiments (Table 1, entry 9). These results
clearly indicated that the [CuII (BAPTE) Cl2] is the catalytic active site.
To further investigate the catalytic activity of this catalyst in the synthesis of triazoles, under the
optimized reaction conditions, different benzyl bromides were reacted efficiently with
phenylacetylene and sodium azide in the presence of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2, and
the corresponding 1,4−disubstituted 1,2,3−triazoles were obtained in good to excellent yield
(79−98%). Under the same conditions, the reactions of phenylacetylene with butyl bromide and
4−nitrobenzyl chloride proceeded efficiently to provide the desired 1,4−disubstituted
1,2,3−triazoles in 95% and 81% yield, respectively (entries 4 and 5). The reaction of substituted
pheneylacetylenes such as 3−methoxy and 4−chlorophenylacetylene with substituted benzyl
bromides was successfully performed and the desired 1,2,3−triazoles were produced in high yields
(entries 7 and 8).
The stability of the CuII (BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 catalyst was monitored using multiple
sequential reaction of 4−bromobenzyl bromide with phenylacetylene and sodium azide in the
presence of sodium ascorbate. At the end of the reaction, the catalyst was separated as described in
the experimental section. Then, the recovered catalyst was used in the next run with fresh
9

4−bromobenzyl bromide, phenylacetylene and sodium azide. The catalyst was consecutively reused
five times without detectable catalyst leaching or significant loss of its activity (Table 3). The nature
of recovered catalyst was investigated by FT-IR spectroscopy. As can be seen, the FT-IR spectrum
of the reused catalyst is similar to fresh catalyst which shows the stability of the reused catalyst
during the catalytic cycles (Fig. 1).
4. Conclusions
In summary, a new copper (II) complex–POM hybrid material was prepared via covalent interaction
2−
.
of 1,2−bis(p−aminophenylthio)ethane (BAPTE), and a Lindqvist type polyoxometalate, Mo6O19
This new hybrid material was characterized and used as catalyst for efficient preparation of various
1,2,3−triazoles under mild conditions. The influence of the polyoxometalate on the catalytic activity
of the catalyst was investigated. Short reaction times, excellent yields, easy work−up and reusability
and stability of the catalyst are noteworthy advantages of this method.
Acknowledgement
Partial support of this work by the research council of the University of Isfahan is acknowledged.
References:
[1] A. Dolbecq, E. Dumas, C. R. Mayer, P. Mialane, Chem. Rev. 110 (2010) 6009–6048.
[2] J. Zhang, F. Xiao, J. Hao, Y. Wei, Dalton Trans., 41(2012) 3599-3615.
[3] M. P. Santonia, G. S. Hanana, B. Hasenknopf, Coord. Chem. Rev. 281 (2014) 64–85.
[4] D. Y. Du, J. S. Qin, S. L. Li, Z. M. Su, Y. Q. Lan, Chem. Soc. Rev. 43 ( 2014) 4615−4632.
[5] D. Y. Du , L. K. Yan, Z. M. Su, S. L. Li, Y. Q. Lan, E. B. Wang, Coord. Chem. Rev. 257 (2013)
702–717.
[6] C. P. Pradeep, D. L. Long, G. N. Newton, Y. F. Song, L. Cronin, Angew. Chem. 120 (2008)
4460−4463; Angew. Chem. Int. Ed. 47 (2008) 4388−4391.
[7] J. Li, I. Huth, L. M. Chamoreau, B. Hasenknopf, E. Lacôte, S. Thorimbert, M. Malacria, Angew.
Chem. 121 (2009) 2069−2072; Angew. Chem. Int. Ed. 48 (2009) 2035−2038.
10

[8] K. Pamin, M. Prończuk, S. Basg, W. Kubiak, Z. Sojka, J. Poltowiks, Inorg. Chem. Commun. 59
(2015) 13−16.
[9] H. R. Allcock, E. C. Bissell, E. T. Shaw, Inorg. Chem. 12 (1973) 2963–2968.
[10] X. Yang, T. Waters, X. B. Wang, R. A. J. O’Hair, A. G. Wedd, D. A. Dixon , L. S. Wang, J.
Phys. Chem. A 108 (2004) 10089–10093.
[11] S. Bank, S. Liu, S. N. Shaikh, X. Sun, J. Zubieta, P. D. Ellis, Inorg. Chem. 127 (1988) 3535–
3543.
[12] A. Dolbecq, C. M. Draznieks, P. Mialane, J. Marrot, G. Férey, F. Sécheresse, Eur. J. Inorg.
Chem. 15 (2005) 3009−3018.
[13] S. T. Zheng, J. Zhang, G. Y. Yang, Angew. Chem. Int. Ed. 47 (2008) 3909−3913.
[14] M. Moghadam, V. Mirkhani, S. Tangestaninejad, I. M. Baltork and M. Moshref Javadi,
Polyhedron 29 (2010) 648–654.
[15] M. Moghadam, V. Mirkhani, S. Tangestaninejad, I. M. Baltork, M. Moshref Javadi, Inorg.
Chem. Commun. 13 (2010) 244–249.
[16] V. Mirkhani, M. Moghadam, S. Tangestaninejad, I. Mohammadpoor−Baltork, N. Rasouli,
Inorg. Chem. Commun. 10 (2007) 1537−1540.
[17] V. Mirkhani, M. Moghadam, S. Tangestaninejad, I. Mohammadpoor−Baltork, N. Rasouli,
Appl. Catal. A: Gen. 334 (2008) 106−111.
[18] V. Mirkhani, M. Moghadam, S. Tangestaninejad, I. Mohammadpoor−Baltork, N. Rasouli,
Catal. Commun. 9 (2008) 219−223.
[19] Z. Qu, K. Yu, Z. Zhao, Z. Su, J. Sha, C. Wang , B. Zhou, Dalton Trans. 43 ( 2014) 6744−6751.
[20] L. Liang, D. Astruc, Coord. Chem. Rev. 255 (2011) 2933–2945.
[21] Y. Xing, N. X. Wang, Coord. Chem. Rev. 256(2012) 938–952.
[22] B. Schulze, U.S. Schubert, Chem. Soc. Rev. 43 (2014), 2522–2571.
[23] W. Tanga, M. L. Becker, Chem. Soc. Rev.43 (2014) 7013–7039.
[24] K. Kempe, A. Krieg, C. R. Becer, U. S. Schubert, Chem. Soc. Rev, 41( 2012) 176–191.
11

[25] C. E. Hoyle, A. B. Lowe, C. N. Bowman, Chem. Soc. Rev. 39 (2010) 1355−1387.
[26] Y. Zhang, S. Luo, Y. Tang, L. Yu, K.−Y. Hou, J.−P. Cheng, X. Zeng, P. G. Wang, Anal.
Chem. 78 (2006) 2001–2008.
[27] V. V. Rostovtsev, L. G. Green, V. V. Fokin, K. B. Sharpless, Angew. Chem. Int. Ed. 41
−2599.
(2002) 2596
−3064.
[28] C. W. Tornøe, C. Christensen, M. J. Meldal, Org. Chem. 67 (2002) 3057
[29] J. F. Lutz, Z. Zarafshani, Adv. Dru. Deliv. Rev. 60(2008) 958–970.
−36.
[30] A. B. Lowe, Polym. Chem. 1 (2010) 17
[31] R. E. Ruther, M. L. Rigsby, J. B. Gerken, S. R. Hogendoorn, E. C. Landis, S. S. Stahl, R. J.
Hamers, J. Am. Chem. Soc.133 (2011) 5692–5694.
[32] A. Devadoss, C. E. D. Chidsey, J. Am. Chem. Soc.129 (2007) 5370−5371.
[33] J. E. Hein, V. V. Fokin, Chem. Soc. Rev. 39 (2010) 1302−1315.
[34] M. Araghi, V. Mirkhani, M. Moghadam, S. Tangestaninejad I. Mohammdpoor−Baltork, Dalton
Trans. 41 (2012) 3087−3094.
[35] M. Araghi, V. Mirkhani, M. Moghadam, S. Tangestaninejad I. Mohammdpoor−Baltork, Dalton
Trans. 41 (2012) 11745−11752.
[36] N. H. Hur, W. G. Klemperer, R. C. Wang, Inorg.Synth. 27 (1990) 77–78.
[37] G. Mukherjee, S. N. Poddar, Transition Met.Chem. 35 (1988) 58−63.
[38] Y. Wei, B. Xu, C. L. Barnes, Z. Peng, J. Am. Chem. Soc. 123 (2001) 4083–4084.
[39] Y. Zhu, L. S. Wang, J. Hao, Z. C. Xiao, Y. G. Wei , Y. Wang, Cryst. Growth Des. 9 (2009)
3509 –3518.
[40] D. Tasis, N. Tagmatarchis, A. Bianco, M. Prato, Chem. Rev. 106 (2006) 1105−1136.
[41] R. S. Mülliken, W. B. Person, Molecular complexes, Wiley−VCH, New York, 1969.
[42] B. Xu, Y. Wei, C. L. Barnes and Z. Peng, Angew. Chem., Int. Ed. 40 (2001) 2290–2292.
[43] K. Izutsu, Electrochemistry in Nonaqueous Solutions, Wiley−VCH Verlag GmbH & Co.
KgaA, 2002, p. 223, Ch. 8.
12

[44] A. B. P. Lever, Inorg. Chem. 30 (1991) 1980–1985.
[45] A. B. P. Lever, Inorg. Chem. 29 (1990) 1271–1285.
[46] G. S. Yang, H. Y. Zang, Y. Q. Lan, X. L. Wang, C. J. Jiang, Z. M. Su and L. D. Zhu,
CrystEngComm, 13 (2011) 1461–1466.
[47] Z. Y. Shi, X. J. Gu, J. Peng, X. Yu, E. B. Wang, Eur. J. Inorg. Chem. 2006 (2006) 385-388.
[48] Z. Y. Shi, X. J. Gu, J. Peng, Y. H. Chen, J. Solid State Chem. 178 ( 2005) 1988-1995.
[49] Z. Y. Shi, J. Peng, C. J. Gomez-Garcia, S. Benmansour, X. J. Gu, J. Solid State Chem.179(
2006) 253-265.
[50] X. J. Gu, J. Peng, Z. Y. Shi, Y. H. Chen, Z. G. Han, E. B. Wang, J. F. Ma, Inorg. Chim. Acta,
358 (2005) 3701-3710.
[51] Y. Yu, H. Ma, H. Pang, L. Zhang, S. Li, C. Zhao, Z. Zhang, RSC Adv. 4 (2014) 61210–61218.
[52] P. S. Braterman, V.A. Wilson, j.organometal. chem. 31(1971)131-135.
[53] M. Tavassoli, A. Landarani−Isfahani, M. Moghadam, S. Tangestaninejad, V. Mirkhani, I.
Mohammadpoor−Baltork, Appl. Catal. A: Gen. 503 (2015) 186–195.
[54] M. Tavassoli, A. Landarani−Isfahani, M. Moghadam, S. Tangestaninejad, V. Mirkhani, I.
Mohammadpoor−Baltork, ACS Sust. Chem. Eng. (2016) DOI: 10.1021/acssuschemeng.5b01432.
13

Fig. 1. The structure of hexamolybdate ion [(n−C4H9)4N]2[Mo6O19].
Fig . 2. The FT−IR spectra of POM, BAPTE, hybrid compound and recycled hybrid compound.
Fig. 3. 1H NMR spectrum of: (a) BAPTE and (b) (BAPTE)−[n−Bu4N]4[Mo6O18]2
14

Table 1. Copper−catalyzed cycloaddition reaction of 4−bromobenzyl bromide and
phenylacetylene catalyzed by CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 .a
N
N
CuII(BAPTE)-[n-Bu4N]4[Mo6O18]2
Br
N
Ph
H
+
+
NaN3
Ph
Br
Solvent/ RT/ 2 h
Br
Entry
Cu (mol%)
Solvent
Yield(%)b
1
2c
3
4
5
6
7
8
9
0
H2O/DMSO (1:10)
H2O/DMSO (1:10)
H2O/DMSO (1:10)
H2O/DMSO (1:10)
H2O/DMSO (1:10)
H2O
5
1
10
51
98
98
28
76
23
Trace
0.5
1
1.5
1
1
DMSO
CuCl2
H2O/DMSO (1:10)
H2O/DMSO (1:10)
(n−Bu4N)2[Mo6O19]
aReaction conditions: Phenylacetylene (1.3 mmol), 4−bromobenzyl bromide (1 mmol),
sodium azide (1.1 mmol), sodium ascorbate (5 mol%), solvent (3 mL) under air
atmosphere.
bIsolated yields.
cWithout sodium ascorbate.
15

Table 2. CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2 catalyzed three−component synthesis of
1,4−disubstituted 1,2,3−triazoles from benzyl halides.a
Entry
1
Phenylacetylene
Benzyl halide
Product
Time (min)
90
Yield (%)b
98
2
3
80
94
83
150
4
5
100
165
95
81
6
7
185
90
79
98
8
100
94
aReaction conditions: Phenylacetylenes (1.3 mmol), benzyl halide (1 mmol), sodium azide (1.1
mmol), sodium ascorbate (5 mol%), catalyst (1 mol%, 0.03 g), solvent (3 mL) under air
atmosphere.
bIsolated yields.
16

Table 3. Reusability of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2
in the reaction of 4−bromobenzyl bromide with phenylacetylene
and sodium azide.a
Run
1
Yield (%)b
Time (min)
Cu leached (%)c
98
95
95
95
95
90
90
90
90
90
0.2
0
2
3
0
4
0
5
0
aReaction conditions: Phenylacetylene (1.3
mmol),
4−bromobenzyl bromide (1 mmol), sodium azide (1.1),
catalyst (1 mol%), solvent (3 mL).
bIsolated yields.
cDetermined by ICP.
17

Scheme 1. Synthesis of 1,2,3−triazoles catalyzed by CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2
18

Scheme 2. Preparation of CuII(BAPTE)Cl2−[n−Bu4N]4[Mo6O18]2
19

Fig. 1. The structure of hexamolybdate ion [(n−C4H9)4N]2[Mo6O19].
20

Fig. 2. The FT−IR spectra of POM, BAPTE, hybrid compound and recycled hybrid
compound.
21

(a)
(b)
Fig. 3. 1H NMR spectrum of: (a) BAPTE and (b) (BAPTE)−[n−Bu4N]4[Mo6O18]2
22

A new copper(II) complex-polyoxometalate hybrid catalyst based on
covalent interaction between 1,2−bis(p−aminophenylthio)ethane,
(BAPTE), and a Lindqvist type polyoxometalate, Mo6O19 −, is
2
synthesized, characterized and used as a highly efficient heterogeneous
catalyst for click reaction.
23