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Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247

Contents lists available at ScienceDirect

Journal of Molecular Catalysis A: Chemical

journa l homepage: www.e lsev ier .com/ locate /molcata

d immobilized on amidoxime-functionalized Mesoporous SBA-15: Aovel and highly active heterogeneous catalyst for Suzuki–Miyauraoupling reactions

amin Ghorbani-Vagheia,∗, Saba Hemmatia, Hojat Veisib

Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, 6517838683 Hamedan, IranDepartment of Chemistry, Payame Noor University (PNU), Tehran, Iran

r t i c l e i n f o

rticle history:eceived 28 April 2014eceived in revised form 17 June 2014ccepted 19 June 2014vailable online 27 June 2014

eywords:BA-15/AO/Pd(II)eterogeneous catalyst

a b s t r a c t

Herein we described the synthesis of a novel SBA-15/AO/Pd(II) nanocatalyst by grafting of ami-doxime on SBA-15 and subsequent deposition of palladium chlorides. Prior to grafting of amidoxime(AO), the prepared [2-cyanoethyl]-functionalized Mesoporous SBA-15 through combining of 2-cyanoethyltriethoxysilane and SBA-15 was treated with hydroxylamine. The amidoxime grafted SBA-15(SBA-15/AO) were then used as platform for in situ deposition of Pd complex. The materials werecharacterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmissionelectron microscopy (TEM), energy dispersive X-ray (EDX), inductivity coupled plasma (ICP), nitrogenadsorption–desorption, and Fourier transform infrared (FTIR) spectroscopy. SBA-15/AO/Pd(II) are novel

d nanoparticlesuzuki reactions

phosphine-free recyclable heterogeneous catalyst for Suzuki coupling reaction of aryl halides (I, Br, Cl)with phenylboronic acid to provide the corresponding products. These cross-coupled products were pro-duced in excellent yields under mild conditions at extremely low palladium loading (∼0.2 mol%) withperfect high turnover frequencies (TOFs). The heterogeneous catalyst can be readily recovered by simplefiltration and reused six times with loss in its activity.

© 2014 Elsevier B.V. All rights reserved.

. Introduction

The study of application of metal nanoparticles in catalysis,articularly, on organic transformations, has become a frontierrea of research in nanocatalysis [1]. Among the different metalanocatalysts, palladium nanoparticles (Pd NPs) have gained mucheputation, because palladium is a versatile catalyst in modernrganic synthesis and is widely used for a significant number ofynthetic transformations [2] such as, Heck, Suzuki, Stille and Sono-ashira cross coupling reactions [3–6].

Suzuki coupling is an important reaction in organic chem-stry for the selective synthesis of biaryls [7–12]. Biaryls have

idespread applications in the synthesis of natural products,

harmaceuticals, and advanced materials [13–16]. Many palla-ium complexes have been used as homogeneous catalysts foruzuki reaction [17–19]. Although homogeneous catalytic systemsre known to exhibit better activity than heterogeneous systems

∗ Corresponding author. Fax: +98 811 8380709.E-mail address: rgvaghei@yahoo.com (R. Ghorbani-Vaghei).

ttp://dx.doi.org/10.1016/j.molcata.2014.06.025381-1169/© 2014 Elsevier B.V. All rights reserved.

but for the large scale applications in liquid phase reactions, itcauses greater difficulties such as purification of the final product,recycling of the catalyst, and deactivation via aggregation into inac-tive Pd particles. Further removal of Pd from organic products at theend of the reaction is highly desirable because of its high cost andtoxicity.

However, some heterogeneous palladium catalysts show lowerreactivity than homogeneous ones due to leaching of palladiumfrom the supports. In fact the leached palladium species is respon-sible for the catalytic activity in most of the cases [20–22]. Thus,there is a need to design of new heterogeneous catalysts thatcan retain the activities and selectivities of homogeneous cata-lysts. Now it is well known that the nature of supports playsa key role in palladium-based heterogeneous catalysis. Amongdifferent supports, mesoporous silica materials remain the mostpopular choice because of their relatively low cost, high thermal,

mechanical stability and good catalytic performance [23]. SBA-15and MCM-41 are the representative example for these types ofmaterials and have been used as supports for palladium catalysts[24–26].

R. Ghorbani-Vaghei et al. / Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247 241

/AO/P

2

2

asco5hwwtdtf

2

a3rsdfsgt

Scheme 1. Schematic diagram of SBA-15

. Experimental

.1. Preparation of SBA-15

All chemicals were purchased from Merck except Pluronic123nd hydroxylamine hydrate which were obtained from Aldrich. Theynthesis of SBA-15 was performed following a well-known pro-edure [27]. In short explanation For the SBA-15 synthesis, 4.0 gf Pluronic P123 was dissolved in 50 mL of water and stirred forh at room temperature. The mixture was added to 120 mL of 2 Mydrochloric acid solution and remained for 2 h. Then, 8.5 g of TEOSas added to that solution and stirred for 24 h at 35 ◦C. The mixtureas then aged at 80 ◦C for 24 h without stirring. After comple-

ion of the reaction, the solid products were filtered, washed witheionized water, and air-dried overnight. The P123 was removedhoroughly with hot ethanol/water (3:2) using a Soxhelet apparatusor 24 h. It was dried in air at 100 ◦C overnight.

.2. Preparation of amidoxime groups in SBA-15 (SBA-15/AO)

To a 100 mL of round-bottom flask were introduced 30 mL ofnhydrous toluene and 2.0 g of SBA-15 and 0.18 g (1.5 mmol) of-(trimethoxysilyl)propanenitrile were added. The solution wasefluxed for 24 h under an inert atmosphere, filtered and washedubsequently with toluene, dichloromethane, and methanol, andried under reduced pressure at 80 ◦C for 10 h. The [2-cyanoethyl]-

unctionalized SBA-15 (1 g) were immersed in NH2OH aqueousolution (50 mL, 50%) at 65 ◦C for 5 h (Scheme 1). The amidoximeroups in SBA-15 (SBA-15/AO) were filtrated off, washed with dis-illed water for several times and dried.

d(II) and SBA-15/AO/Pd(o) fabrications.

2.3. Immobilization of Pd(II) ions on the surface of SBA-15/AO

1.0 g of SBA-15/AO and 0.089 g of palladium chloride (0.5 mmol)in 40 mL of acetonitrile was stirred at room temperature for 4 h. Thebrown resulting solid was filtered, washed with acetone and THFand dried in vacuum at 60 ◦C for 3 h to give SBA-15/AO/Pd(II). ThePd(II) content of Pd–SBA-15/AO surface was obtained by using ICPspectroscopy to test the concentration of Pd2+ solution before andafter preparation reaction, it is 0.22 mmol/g.

2.4. Reduction of Pd(II) ions on the surface of SBA-15/AO

The reduction of SBA-15/AO/Pd(II) by hydrazine hydrate wasperformed as follows: 50 mg of SBA-15/AO/Pd(II) was dispersed in60 mL of water, and then 100 �L of hydrazine hydrate (80%) wasadded. The pH of the mixture was adjusted to 10 with 25% ammo-nium hydroxide and the reaction was carried out at 95 ◦C for 2 h.The final product SBA-15/AO/Pd(0) was washed with water andacetone, and dried in vacuum at 50 ◦C.

2.5. Suzuki–Miyaura coupling reaction

In a typical reaction, 10 mg of the catalyst (10 mg = 0.002 mmolPd) was placed in a 25 mL Schlenk tube, 1 mmol of the aryl halidein 5 mL of water/ethanol (1:2) was added 0.134 g (1.1 mmol) ofphenyl boronic acid, 0.276 mg of K2CO3 (2 mmol). The mixture was

then stirred for the desired time at 50 ◦C. The reaction was mon-itored by thin layer chromatography (TLC). After completion ofreaction, the reaction mixture was cooled to room temperature andthe catalyst was recovered by centrifuge and washed with ethyl

242 R. Ghorbani-Vaghei et al. / Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247

F1

aauc

3

3

oplhaa

(sc8dab2i

Table 1The pore diameters (DBJH), BET surface area (SBET) and the total pore volumes (Vtotal)from N2 adsorption–desorption isotherms for the synthesized adsorbents (SBA-15and SBA-15/AO/Pd(II)).

Entry Samples SBET (m2 g−1) Total pore volume(cm3 g−1)

Mean porediameter (nm)

1 SBA-15 752 0.810 4.31

ig. 1. FT-IR spectra of (a) SBA-15, (b) SBA-15-Et-CN, (c) SBA-15/AO, (b) SBA-5/AO/Pd(II).

cetate and ethanol. The combined organic layer was dried overnhydrous sodium sulfate and evaporated in a rotary evaporatornder reduced pressure. The crude product was purified by columnhromatography.

. Results and discussion

.1. Characterization of SBA-15/AO/Pd(II)

In continuation of our interest in exploring catalytic method-logy [28–30], herein, we report an efficient approach for thereparation of amidoxime-functionalized SBA-15 anchored pal-

adium (II) complex (SBA-15/AO/Pd(II)) and their application aseterogeneous catalyst in Suzuki cross-coupling reaction undermbient condition. The pathways of SBA-15/AO/Pd(II) fabricationre shown in Scheme 1.

Fig. 1 shows the FT-IR spectra of (a) SBA-15, (b) SBA-15-Et-CN,c) SBA-15/AO and (d) SBA-15/AO/Pd(II). As it is seen, the typicalilica bands associated with the main inorganic backbone can belearly observed in all spectra. The typical Si O Si bands at 468,09 and 1052 cm−1 present in all samples are attributed to the con-ensed silica network [31]. The spectrum of parent SBA-15 exhibits

broad band at 1633 cm−1 due to O H bending vibration. Curveshows the spectrum of SBA-15-Et-CN and signal appeared at

225 cm−1 is attributed to the presence of CN stretching. The bend-ng vibration of C H group is also observed at 2850–2950 cm−1.

Fig. 2. EDX analysis of S

2 SBA-15/AO/Pd(II) 325 0.511 6.7

Meanwhile, the intensity of the peak at 960 cm−1 (related to thebending vibration of Si OH on SBA-15) significantly decreases aftergrafting with 2-cyanoethyltriethoxysilane. This result shows thatcyanoethyl has been attached into the SBA-15 matrix. Interestingly,after hydroxylamine treatment, the absence of CN stretching andthe signals appeared at 3300 cm−1 attributable to the N H stretch-ing of amine generated through amidoxime-functionalization. Thusit is evident that the cyano groups are converted into amidoximegroups. In Fig. 1(d), the stretching frequency at 576 cm−1 in thespectrum of Pd(II)–SBA-15 indicates �Pd-N [32].

Presence of Pd atoms in amidoxime-functionalized MesoporousSBA-15 nanocatalyst was also confirmed by the EDX detector cou-pled to the SEM which showed the presence of Si and O in Fig. 2.The peaks corresponding to Si and O were originated by SBA-15.The peaks derived from Cu were from the copper grid used in SEMmeasurements.

The results for N2 adsorption–desorption containing the porediameters (DBJH), the BET surface area (SBET) and the total porevolumes (Vtotal) of the calcined SBA-15 sample together with theSBA-15/AO/Pd(II) sample are summarized in Table 1. In addition,the nitrogen adsorption–desorption studies demonstrated that asignificant decrease in pore size by probability of silylation of theSBA-15 channels was observed.

The isotherms were all Type IV with a H1 hysteresis loop anda steep increase in adsorption at relative pressures of 0.58–0.82for SBA-15 samples approximately attributed to capillary nitrogencondensation according to IUPAC classification (Fig. 2). This is typ-ical for mesoporous materials with ordered pore structures [33].Additionally, upon modification the surface area and pore volumedecreased obviously. These results are in good agreement with thefact that the surface modification indeed occurred inside the pri-

mary mesopores of the SBA-15 (Fig. 3).

The small-angle X-ray diffraction patterns of SBA-15 and thecatalyst SBA-15/AO/Pd(II) are shown in Fig. 4. The fresh SBA-15 shows a strong diffraction peak and two small diffraction

BA-15/AO/Pd(II).

R. Ghorbani-Vaghei et al. / Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247 243

Fig. 3. (a) Adsorption/desorption isotherms of nitr

pcltoim

1m

showing the size distribution of the Pd NPs for the fresh and re-

Fig. 4. Small angle XRD patterns of (a) SBA-15 and (b) SBA-15/AO/Pd(II).

eaks for the 100, 110 and 200 planes. All the peaks indi-ate SBA-15 has a well-defined hexagonal symmetry and hasong-range ordering of structure. Comparison of the diffrac-ion patterns of SBA-15/AO/Pd(II) and SBA-15 indicates that therdered cubic mesoporous structure of the material remainsntact even after formation of the Pd complex in SBA-15

atrix.

Typical SEM images with different magnifications for SBA-

5/AO/Pd(II) are shown in Fig. 5. Fig. 5(a) reveals that theorphology of SBA-15/AO/Pd(II) consists of rod-shaped particles

Fig. 5. SEM images of S

ogen of (a) SBA-15 and (b) SBA-15/AO/Pd(II).

aggregated into bundles. Higher magnification (Fig. 5(b)) showsthat the particles are multifaceted and the pore channels run par-allel to the particle main axis.

XRD analysis of SBA-15/AO/Pd(0) catalyst confirmed the for-mation of palladium nanoparticles, which exhibited (1 1 1), (2 0 0),(2 2 0) and (3 1 1) crystallographic planes of face-centered cubic(fcc) palladium at 39◦, 46◦, 67◦ and 82◦, respectively (JCPDS No.89-4897) (Fig. 6).

Furthermore, the structural elucidation of the fresh SBA-15/AO/Pd(0) and reused SBA-15/AO/Pd(0) were performed insome details using TEM technique. TEM images of the catalysts(Fig. 7(a) and (c)) shows that the attachment of organic compo-nents to the SBA-15 materials has no distinct influence on themorphology of composition. TEM images obtained from recoveredSBA-15/AO/Pd(0) showed that the Pd(II) ions initially presented inthe catalyst are reduced to Pd(0) nanoparticles in SBA-15 mate-rial. TEM images of the used catalyst after 6 runs are shown inFig. 7(c). As it is seen, the dark spots are the Pd nanoparticlesthat their formations can mainly due to reduction process withSuzuki reaction solvents (H2O/EtOH) [34]. It is notably, after usingSBA-15/AO/Pd(II), no palladium ion could be detected in the liq-uid reaction mixtures by atomic absorption spectroscopy, but, theagglomeration of Pd NPs must be responsible for the deactiva-tion of the catalyst with increasing reaction cycles. A histogram

used catalyst is shown in Fig. 7(b) and (d), based on the dataobtained, the average size of Pd NPs in the re-used catalyst wasincreased.

BA-15/AO/Pd(II).

244 R. Ghorbani-Vaghei et al. / Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247

Fig. 6. XRD pattern of SBA-15/AO/Pd(0).

Fig. 7. TEM images and histogram showing the size distribution for (a and b) fr

Scheme 2. SBA-15/AO/Pd(II) for Suzuki cross-coupling reaction.

3.2. Catalytic application of SBA-15/AO/Pd(II) in the Suzukicoupling reactions

After structure characterization of the prepared nanocatalysts(Pd(II)–SBA-15), its catalytic activity was investigated employingit in the Suzuki reaction (Scheme 2). To find the best conditions,the reaction between iodobenzene and phenylboronic acid was

chosen as a model reaction, for which influences of different param-eters were examined to obtain the best possible combination. The

esh SBA-15/AO/Pd(0), and for (c and d) reused 6 cycles SBA-15/AO/Pd(0).

R. Ghorbani-Vaghei et al. / Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247 245

Table 2Optimization of the reaction of iodobenzene with phenylboronic acid in the presenceof SBA-15/AO/Pd(II) under thermal condition.a

Entry Solvent Base Pd (mol%) T (◦C) t (h) Yield (%)b

Solvent effect1 H2O K2CO3 0.002 50 10 502 DMF K2CO3 0.002 50 2 653 EtOH K2CO3 0.002 50 2 704 CH3CN K2CO3 0.002 50 5 705 H2O/EtOH (1:1) K2CO3 0.002 50 0.4 926 H2O/EtOH (1:2) K2CO3 0.002 50 0.3 987 H2O/EtOH (2:1) K2CO3 0.002 50 1 908 Solvent-free K2CO3 0.002 50 12 40

Base effect9 H2O/EtOH (1:2) K2CO3 0.002 50 0.3 98

10 H2O/EtOH (1:2) Na2CO3 0.002 50 2 7011 H2O/EtOH (1:2) Et3N 0.002 50 4 6512 H2O/EtOH (1:2) NaHCO3 0.002 50 2 7513 H2O/EtOH (1:2) K3PO4 0.002 50 5 7514 H2O/EtOH (1:2) No base 0.002 50 12 Trace

Temperature effect15 H2O/EtOH (1:2) K2CO3 0.002 50 0.3 9816 H2O/EtOH (1:2) K2CO3 0.002 25 3 8017 H2O/EtOH (1:2) K2CO3 0.002 60 0.3 92

Pd loading18 H2O/EtOH (1:2) K2CO3 0.002 50 0.3 9819 H2O/EtOH (1:2) K2CO3 0.001 50 5 8520 H2O/EtOH (1:2) K2CO3 0.003 50 0.3 9021 H2O/EtOH (1:2) K2CO3 0.000 50 24 0

a Reaction conditions: iodobenzene (1.0 mmol), phenylboronic acid (1.1 mmol),c

pc

wlwwma

(i(bo

eiaab1P

sosaeowiydp

Table 3Heterogeneous Suzuki–Miyaura reaction of aryl halides with phenylboronic acidcatalyzed by SBA-15/AO/Pd(II).a

Entry RC6H4X X Time (h) Yield (%)b TONc TOF (h−1)d

1 H I 0.3 98 490 16332 H Br 1 98 490 490.03 H Cl 10 80 400 40.004 4-CH3 I 0.5 98 490 980.05 4-CH3 Br 1.5 95 475 316.66 4-CH3O Cl 12 75 375 31.257 4-COCH3 I 1 95 475 475.08 4-COCH3 Br 3 90 450 150.09 4-COCH3 Cl 15 70 350 23.33

10 4-CH3O I 0.5 98 490 980.011 4-CH3O Br 1.2 96 480 400.012 4-Cl I 0.3 98 490 163313 4-Cl Br 1 95 475 475.014 2-CH3O I 0.7 98 490 700.015 2-CH3O Br 1.5 96 480 320.016 4-CHO I 1 95 475 475.017 4-CHO Br 4 90 450 112.518 3-NO2 I 0.5 96 480 960.019 3-NO2 Br 2 92 460 230.020 4-CN I 1 98 490 490.021 1-Naphthyl I 1.2 96 480 400.022 2-Thienyl I 0.8 98 490 612.523 2-Thienyl Br 1.2 95 475 395.8

a Reactions were carried out under aerobic conditions in 2 mL of mixture of EtOHand H2O (2:1), 1.0 mmol aryl halide, 1.1 mmol phenylboronic acid and 2 mmol K2CO3

in the presence of catalyst (0.010 g, 0.002 mol% Pd) at 50 ◦C.b

ethanol and water, and reused in a next reaction. The data listed in

atalyst, base (2 mmol) and solvent (2 mL).b Isolated yields were calculated from gas chromatography.

arameters included solvent, reaction temperature, base, catalystoncentration and the reaction period.

Initially, the single solvents such as DMF, EtOH, CH3CN, and H2Oere studied. As could be seen in Table 2, the single solvents gave

ow yields for the reaction (Table 2, entries 1–4). However, whene adopted the organic/aqueous co-solvent, high yields of 90–98%ere obtained (Table 2, entries 5–7). The merit of the co-solventay be attributed to the good solubility of the organic reactants

nd the inorganic base.Next, the effects of bases on the Suzuki reaction in EtOH/H2O

2:1) were examined. The organic and inorganic bases includ-ng Et3N, NaHCO3, Na2CO3, K3PO4 and K2CO3 were investigatedTable 2, entries 9–13). As shown in Table 2, K2CO3 was the bestase for the reaction with high yield. However, a low yield wasbtained without any base (Table 2, entry 14).

It was also found that the reaction temperature has a great influ-nce on this transformation (Table 2, entries 15–17). The obviousmprovement in the conversion (98%) was achieved for the reactiont 50 ◦C (Table 2, entry 15). The influence of palladium loading waslso investigated (Table 2, entries 18–21). As shown in Table 1, theest result was obtained with 0.002 mol% of catalyst (Table 2, entry8). The coupling reaction did not proceed at all in the absence ofdNPs [35,36].

With a reliable set of conditions in hand (Table 2, entry 6), thecope and generality of the developed protocol with respect to vari-us aryl halides were investigated using our catalyst. The results areummarized in Table 3. When phenylboronic acid was coupled withryl iodides and bromides containing both electron-donating andlectron-withdrawing groups, the corresponding products werebtained in excellent yields. The coupling reaction of aryl chloridesith phenylboronic acid required extended reaction time than aryl

odides and bromides, producing the desired products in moderate

ield (Table 3, entries 3, 6, 9). The reactions of sterically hin-ered ortho-position halides and bulky 1-bromonaphthalene withhenylboronic acid also provided good yields of the desired biaryls

Isolated yields were calculated from gas chromatography.c TON, turnover number, moles of aryl halides converted per mole of Pd.d TOF, turnover frequencies.

under the optimized reaction conditions, respectively (entries 13,14 and 6). The Suzuki–Miyaura cross-coupling reaction of het-eroaryl halides such as 2-bromothiophene and 2-iodothiophenewith phenylboronic acid gave the corresponding coupled prod-ucts in 95% and 98% yields, respectively (entries 22 and 23). In thecase of iodo- and bromo-halides the corresponding products wereobtained exclusively with very high turnover frequencies (TOF)(Table 3).

In general, Suzuki coupling reactions catalyzed by solid-supported Pd follow the usual reaction mechanism (similar tohomogenous catalysis), but the full understanding of mechanismin heterogeneous conditions still remains an open question. Inorder to determine whether the catalysis was due to the SBA-15/AO/Pd(II) complex or to a homogeneous palladium complexthat comes off the support during the reaction and then returnsto the support at the end (release and recapture mechanism), weperformed the hot filtration test [37]. We focused on the couplingreaction of iodobenzene with phenylboronic acid (1.1 equiv.). Wefiltered off the SBA-15/AO/Pd(II) complex after 10 min of reactiontime and allowed the filtrate to react further. The catalyst filtra-tion was performed at the reaction temperature (50 ◦C) in order toavoid possible re-coordination or precipitation of soluble palladiumupon cooling. We found that, after this hot filtration, no furtherreaction was observed and no palladium could be detected in thehot filtered solution by atomic absorption spectroscopy (AAS). Thisresult suggests that the palladium catalyst remains on the sup-port at elevated temperatures during the reaction. Based on theseevidences, a reaction mechanism for Suzuki coupling with the pre-pared nanocatalysts was proposed (Scheme 3).

The recycling performance of SBA-15/AO/Pd(II) was investi-gated in the reaction of iodobenzene and phenylboronic acid.SBA-15/AO/Pd(II) was filtered from the reaction, washed with hot

Fig. 8 show that SBA-15/AO/Pd(II) could be reused six times withsignificant loss of catalytic activity. This result also demonstratedthat amidoxime groups play a key role to improve the stability of

246 R. Ghorbani-Vaghei et al. / Journal of Molecular Catalysis A: Chemical 393 (2014) 240–247

Fs

Scheme 3. Possible mechanism o

ig. 8. The recycling of the SBA-15/AO/Pd(II) for the Suzuki coupling reaction underimilar conditions.

f Suzuki coupling reaction.

the palladium nano particles. Actually, about 20% of catalytic activ-ity was lost after six cycles of reaction because of the agglomerationof Pd NPs, that can make this conclusion based on reused TEM after6 cycles (Fig. 7).

4. Conclusion

In conclusion, a new mesoporous silica supported palladium(II) catalyst had been successfully prepared via sequential graft-ing of several organic molecules. Also, we have developed a novel,phosphine-free, heterogeneous, practical and economic catalystsystem for the Suzuki–Miyaura cross-coupling reaction of aryl

halides (I, Br, Cl) with phenylboronic acid by using SBA-15/AO/Pd(II)as catalyst under mild reaction conditions. It could be easily recov-ered by simple filtration and a good yield was obtained even afterthe catalyst was reused six times. These advantages make this

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ethodology attractive for the development of large-scale indus-rial synthesis.

cknowledgements

We are thankful to Bu-Ali Sina University, Center of Excellencend Development of Chemical Methods (CEDCM) and Payame Noorniversity (PNU) for financial support.

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