International Journal of Bio-Inorganic Hybrid Nanomaterials by ijbihn

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 73-78

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Catalytic Synthesis N-alkyl-3-acetyl-2-methylpyrroles using ZnO Nanostructure Ashraf Sadat Shahvelayati1*, Maryam Sabbaghan2, Solmaz Banihashem3 1, 3

Department of Chemistry, Yadegar-e-Imam Khomeini (RAH) Shahre-rey Branch, Islamic Azad University, Tehran, Iran

Department of Chemistry, Faculty of Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran

Received: 3 February 2015; Accepted: 6 April 2015

ABSTRACT $ VLPSOH JUHHQ V\QWKHVLV RI 1 DON\O DFHW\O PHWK\OS\UUROH GHULYDWLYHV XVLQJ =Q2 QDQRSDUWLFOHV IURP WKH WKUHH FRPSRQHQW UHDFWLRQ RI DOLSKDWLF DPLQHV DFHW\ODFHWRQH DV D GLFDUERQ\O FRPSRXQG DQG ÄŽ KDORNHWRQHV XQGHU solvent-free condition is described. Keywords: N-alkyl-3-acetyl-2-methylpyrroles; ZnO nanoparticles; Three component reactions; Solvent-free UHDFWLRQV $FHW\ODFHWRQH

1. INTRODUCTION N-heterocyclic compounds received considerable attention in the literature as a consequence of their exciting biological properties and their role a pharmacophores [1]. Of these heterocycles, the synthesis, reactions, and biological activities of pyrrole derivatives stand as an area of research in heteroaromatic chemistry. A number of synthetic methods have been reported for the synthesis of both undecorated, and polysubstituted pyrroles [2]. However, some of these methods have some drawbacks, such as long reaction times, unsatisfactory yields and use of expensive catalysts. Therefore, it is necessary to develop a simple and green method for (*) Corresponding Author - e-mail: avelayati@yahoo.com

the synthesis of pyrrole derivatives without these problems. In recent years multicomponent reactions (MCRs) have performed quantitative revolutions in nitrogencontaining heterocyclic compounds due to their application in biologically active pharmaceutical, agrochemicals and functional materials are becoming important [3-9]. Simple and green synthetic procedures constitute an important goal in organic synthesis. The goals of green chemistry are focused on four of the current demands of human kind which are minimizing waste and pollution, HIÂżFLHQW H[SORLWDWLRQ RI PDWHULDO DQG HQHUJ\ VRXUFHV

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 73-78

Shahvelayati A.S. et al

O O R1 N+2 1

C+3

+ O

C+3 2

Br O

C+3

ZnO-NPs solvent-free rt, -7h

N R1

C+3

R1= n-Bu, cy-+exyl R2= 4-Br-C +4, CO2Et, 4-MeO-C +4

Scheme 1: Nano ZnO catalyzed synthsis of N-alkylpyrroles.

minimizing hazard, and minimizing cost [10]. Therefore, with the development of industrialization, organic chemists have been confronted with a QHZ FKDOOHQJH RI Â¿QGLQJ QRYHO PHWKRGV LQ RUJDQLF V\QWKHVLV WKDW FDQ UHGXFH DQG Â¿QDOO\ HOLPLQDWH WKH LPpact of volatile organic solvents and hazardous toxic chemicals on the environment. So, use of non-toxic, environmentally, friendly, and inexpensive solid catalysts such as ZnO nanoparticle to perform organic reactions has attracted considerable interest [11-13]. In the continuation of our research on the application of MCRs in heterocyclic synthesis, herein, we report DQ HIÂ¿FLHQW WKUHH FRPSRQHQW V\QWKHVLV IRU S\UUROH GHrivatives using ZnO nanoparticles (NPs) as a green and reusable catalyst under solvent-free conditions (Scheme1) [14-17].

2. RESULTS AND DISCUSSION The reaction of aliphatic amines 1, acethylacetone 2, DQG Ä® EURPRNHWRQHV XQGHU VROYHQW IUHH FRQGLWLRQ and ZnO catalyst was studied to produce pyrroles 4 in good yields (Table 1), and it was compared with the situations without catalyst in different solvents (Table 2). 7KH VWUXFWXUHV RI FRPSRXQGV DÂ± I ZHUH FRQÂ¿UPHG by IR, 1HNMR, and 13CNMR spectroscopy. The mass spectra of these compounds displayed molecular ion peaks at appropriate m/z values. For example, the 1HNMR spectrum of 4c in CDCl3 exhibited characWHULVWLF VLJQDOV LQ Ä¯ SSP IRU EXW\O JURXS WRJHWKHU ZLWK RQH WULSOHW DQG RQH TXDUWHW Ä¯ 4.72 respectively) for the ethoxy group, one singlet in

Table 1: Yield of pyrrole derivatives in the presence of ZnO catalyst.

Yield (%)

n-Bu

4-Br-C6H4

n-Bu

CO2Et

n-Bu

4-MeO-C6H4

95a

cy-Hexyl

CO2Et

cy-Hexyl

4-MeO-C6H4

cy-Hexyl

4-Br-C6H4

F \LHOG LQ WKH SUHVHQFH RI =Q2 FDWDO\VW IRU WKH Â¿UVW WLPH

93% in the second run, and 90% in the third run with recycled ZnO.

Ä¯ SSP IRU PHWK\O JURXS DQG RQH VLQJOHW LQ Ä¯ SSP IRU PHWKR[\ JURXS 0RUHRYHU LW VKRZHG RQH VLQJOHW VLJQDO Ä¯ SSP IRU &+ S\UUROH DQG WZR GRXEOHWV Ä¯ SSP IRU WKH DURPDWLF protons. The 13CNMR spectrum of 4c showed 19 signals in agreement with the proposed structure. Partial assignments of these resonances are given in Section 4. The 1H and 13CNMR spectra of the other products are similar to those of 4c. A tentative mechanism for this transformation is proposed in Scheme 2. Enaminones were produced from reaction of 1,3-dicarbonyl compounds and amines. They are an important intermediate in the synthesis of pyrroles. Presumably, enaminone 5, formed by the initial reaction of amine 1 and 1,3- dicarbonyl DWWDFNV Ä® EURPRNHWRQHV DQG DIWHU F\FOL]DWLRQ RI affords products 4. To improve the yield of the target products, we carried out the test reaction in the presence of various solvents and the results are presented (Table 2). It was

Shahvelayati A.S. et al

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 73-78

R1 O

NH2 +

Br R2

NR1

H O R2

HBr

O R2

H2O

Lewis acid site 1

Lewis basic site

Scheme 2: Proposed mechanism for the synthesis of compounds 4.

Table 2: Effect of solvent on synthesis of 4a without catalyst.

Solvent/catalyst

Time (h)

Yield (%)

THF/none catalyst

Ethanol/none

Methanol/none

CH3CN/none

CHCl3/none

ZnO NPs/ Solvent-free

6-7

observed that ZnO exhibited high activity and the corresponding product was performed in high yield. It seems that high surface area and better dispersion of nanoparticles in the reaction mixture are reason for better activities of ZnO NPs. The higher yield was obtained with increasing the amount of catalyst from 5% to 12.5%. Hence the optimum concentration of ZnO NPs was chosen 12.5% mol in the model reaction (Table 3). As a result, solvent-free conditions accelerated the Table 3: Effect of increasing amount of ZnO on the reaction.

Entry 1

ZnO (mmol) 0.05

Yield (%) 43

0.1

0.25

rate of reaction and also high yields were obtained for all products. So, in this research, we successfully prepared pyrroles derivatives in the presence of zinc oxide nanoparticles. As shown in Table1 phenacyl bromides with electron-donating groups such as methoxy group reacted faster than those with electronwithdrawing groups including Br.

3. EXPERIMENTAL DETAIL *HQHUDO All used materials in laboratory are products of Merck, Aldrich, and Fluka companies. In order to detect SURGXFWV 7/& &DUGV VLOLFDJHO * 89 KDV EHHQ HPSOR\HG 7KH FDWDO\VW ZDV SUHSDUHG DQG LGHQWLÂżHG DFcording to reference 18. Morphology and particle size of the catalyst were determined by the SEM and XRD images (Figures 1, 2). IR spectra were obtained using Shimadzu FTIR-460 spectrometer. 1H NMR and 13 C NMR spectra were recorded with a Bruker DRX300 AVANCE instrument in CDCl3 at 300.1 and 75.4 0+] UHVSHFWLYHO\ ÄŻ LQ SSP - LQ +] 0DVV VSHFWUD were obtained on a Finnigan MAT-8430 at 70 eV. Elemental analyses (C, H, N) were performed with a Heraeus CHN-O-Rapid analyzer. 3.2. Preparation of pyrrole derivatives 7KH UHDFWLRQ ZDV FDUULHG RXW DW Â&#x192;& ZLWK WKH PL[WXUH of 1,3-dicarbonyl (1 mmol) and amine (1 mmol) in 75

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Shahvelayati A.S. et al

3.4. Reusability of catalyst EtOAC (2 times) was added to the catalyst and the SUHFLSLWDWH ZDV FHQWULIXJHG DQG Â¿OWHUHG RII 1DQR =Q2 regenerated by washing with hot EtOAc and then with DFHWRQH DQG GU\LQJ RI WKH SUHFLSLWDWH DW Â&#x192;& 7KH recyclability of ZnO NPs was examined in synthesis RI F ZLWK QR VLJQLÂ¿FDQW GHFUHDVLQJ LQ UHDFWLRQ \LHOGV (Table 1).

4. SPECTRAL DATA Figure 1: XRD pattern of ZnO Nanoparticles.

the presence of ZnO NPs as catalyst (12.5% mol), afWHU PLQ Ä® KDORNHWRQH PPRO ZDV DGGHG WR WKH mixture without solvent and was stirred for 6-7 h at r.t. After completion of the reaction (TLC monitoring), WKH SURGXFWV ZHUH SXULÂ¿HG E\ FROXPQ FKURPDWRJUDphy (n-hexane/AcOEt 5:1). 3.3. Preparation of ZnO nanoparticles ,Q D W\SLFDO SURFHGXUH WKH GHÂ¿QLWH DPRXQW RI 1D2+ was dissolved in 30 mL of distilled water under vigorous stirring, followed by the addition of ionic liquid (IL) and 0.3 g Zn(AcO)2 .2H2O to the mixture. The PL[WXUH WUDQVIHU WR D URXQG ERWWRPHG Ã&#x20AC;DVN DQG ZDV UHÃ&#x20AC;X[HG IRU K $IWHU FRROLQJ WR URRP WHPSHUDWXUH WKH SUHFLSLWDWH ZDV FROOHFWHG E\ Â¿OWUDWLRQ DQG ZDVKHG with distilled water and ethanol (96%) several times [18]. Finally, The morphology of ZnO nanoparticles was determined by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) (Figures 1, 2) [18].

Figure 2: SEM image of ZnO Nanoparticles.

Ethyl 5-(4-bromophenyl)-1-butyl-2-methyl-1H-pyrrole-3-carboxylate (4a) Pale yellow oil; 0.40 g (90%). IR: 1689, 1429, 1388, 1270 cm-1. 1HNMR (300 MHz, CDCl3 Ä¯ W + - +] 0H P + &+2), 1.35 (t, 3H, - +] 0H P + &+2), 2.61 (s, 3H, 0H W + - +] &+21 T + - 7.1 Hz, CH22 V + &+ G + - +] &+ G + - +] &+ 13CNMR (75 MHz, CDCl3 Ä¯ 0H 0H 0H 20.1 (CH2), 33.1 (CH2), 44.3 (CH2N), 59.7 (CH2O), 110.5 (CH), 112.5 (C), 121.9 (C), 131.2 (2CH), 132.0 (2CH), 132.5 (C), 134.1 (C), 137.1 (C), 165.9 (CO). MS (EI, 70 eV): m/z (%) 365 (M+2, 10), 363 (M+, 9), 336 (100), 334 (98), 322 (20). Anal. Calcd. for C18H22BrNO2 (364.28): C, 59.35; H, 6.09; N, 3.85%. Found: C, 59.68; H, 6.13; N, 3.69%. Diethyl 1-butyl-5-methyl-1H-pyrrole-2,4-dicarboxylate (4b) Yellow oil; 0.30 g (92%). IR: 1691, 1401, 1393, 1289 cm-1. 1HNMR (300 MHz, CDCl3 Ä¯ W + - 7.3 Hz, Me), 1.31-1.35 (m, 8H, 4 CH2), 1.67-1.69 (m, 2H, CH2 V + 0H W + - +] CH2N), 4.28-4.32 (m, 4H, 2 CH2O), 7.10 (s, 1H, CH). 13 CNMR (75 MHz, CDCl3 Ä¯ 0H 0H 14.6 (Me), 14.7 (Me), 20.1 (CH2), 33.0 (CH2), 47.2 (CH2N), 60.4 (CH2O), 60.6 (CH2O), 113.6 (C), 115.3 (C), 126.1 (CH), 134.9 (C), 164.6 (CO), 165.9 (CO). MS (EI, 70 eV): m/z (%) 281 (M+, 7), 252 (100), 238 (19). Anal. Calcd. for C15H23NO4 (281.35): C, 64.03; H, 8.24; N, 4.98%. Found: C, 63.88; H, 8.11; N, 4.89%.

Shahvelayati A.S. et al

Ethyl 1-butyl-5-(4-methoxyphenyl)-2-methyl-1Hpyrrole-3-carboxylate (4c) Yellow oil; 0.34 g (95%). IR: 1697, 1373, 1244, 1189 cm-1. 1HNMR (300 MHz, CDCl3 Ä¯ W + - 7.2 Hz, Me), 1.17-1.20 (m, 2H, CH2), 1.35 (t, 3H, J +] 0H P + &+2), 2.66 (s, 3H, Me), 3.81-3.84 (m, 2H,CH2N), 3.86 (s, 3H, MeO), T + - +] &+2O), 6.49 (s, 1H, CH), G + - +] &+ G + - Hz, 2CH). 13CNMR (75 MHz, CDCl3 Ä¯ 0H 13.9 (Me), 14.9 (Me), 20.1 (CH2), 33.1 (CH2), 44.2 (CH2N), 55.6 (MeO), 56.9 (CH2O), 109.6 (CH), 112.0 (C), 114.2 (2CH), 126.0 (C), 131.1 (2CH), 133.5 (C), 136.3(C), 159.4 (C), 166.1 (CO). MS (EI, 70 eV): m/z (%) 315 (M+, 11), 286 (100), 272 (22). Anal. Calcd. for C19H25NO3 (315.41): C,72.35; H, 7.99; N, 4.44%. Found: C, 71.88; H, 7.86; N, 4.39%. Diethyl 1-cyclohexyl-5-methyl-1H-pyrrole-2,4-dicarboxylate (4d) Yellow oil; 0.34 g (88%). IR: 1681, 1311, 1265, 1209 cm-1. 1HNMR (300 MHz, CDCl3 Ä¯ Â± P 6H, 2 Me), 1.27â&#x20AC;&#x201C;2.00 (m, 10H, 5 CH2), 2.04 (s, 3H, Me), 3.66 (m, 1H, CHN), 4.28â&#x20AC;&#x201C;4.62 (m, 4 H, 2CH2O), 7.28 (s. 1H, CH). 13CNMR (75 MHz, CDCl3 Ä¯ (Me), 14.0 (Me), 14.3 (Me), 24.9 (CH2), 29.3 (2CH2), 31.1 (2CH2), 54.4 (CH2O), 55.1 (CH2O), 57.8 (CHN), 112.2 (C), 115.9 (C), 126.1 (CH), 133.9 (C), 164.6 (CO), 165.9 (CO). MS (EI, 70 eV): m/z (%) 307 (M+, 12), 224 (100). Anal. Calcd. for C17H25NO4 (307.38): C, 66.43; H, 8.20; N, 4.56%. Found: C, 66.88; H, 8.09; N, 4.51%. Ethyl 1-cyclohexyl-5-(4-methoxyphenyl)-2-methyl-1H-pyrrole-3-carboxylate (4e) Yellow oil; 0.39 g (86%). IR: 1700, 1319, 1255, 1222 cm-1. 1HNMR (300 MHz, CDCl3 Ä¯ Â± P 10H, 5 CH2 W + - +] 0H V 3H, Me), 3.72 (m, 1H, CHN), 3.91 (s, 3H, MeO), 4.12 T + - +] &+2O), 6.31 (s, 1H, CH), 6.98 (d, + - +] &+ G + - +] &+ 13 CNMR (75 MHz, CDCl3 Ä¯ 0H 0H 25.4 (CH2), 26.5 (2CH2), 32.4 (2CH2), 55.0 (MeO), 57.7 (CH2O), 58.8 (CHN), 110.1 (CH), 112.5 (C), 113.9 (2CH), 131.0 (C), 131.7 (2CH), 132.4 (C), 135.7 (C), 159.8 (C), 165.2 (CO). MS (EI, 70 eV): m/z (%)

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341 (M+, 8), 258 (100). Anal. Calcd. for C21H27NO3 (341.44): C, 73.87; H, 7.97; N, 4.10%. Found: C, 73.58; H, 8.09; N, 3.96%. Ethyl 5-(4-bromophenyl)-1-cyclohexyl-2-methyl-1H-pyrrole-3-carboxylate (4f) Yellow oil; 0.52 g (75%). IR: 1717, 1345, 1258, 1227 cm-1. 1HNMR (300 MHz, CDCl3 Ä¯ Â± P 10H, CH2 W + - +] 0H V + 0H P + &+1 T + - Hz, CH22 V + &+ G + - &+ G + - +] &+ 13CNMR (75 MHz, CDCl3 Ä¯ 0H 0H &+2), 26.4 (2CH2), 32.4 (2CH2), 58.0 (CH2O), 58.9 (CHN), 110.8 (CH), 112.9 (C), 121.6 (C), 131.8 (2CH), 132.1 (2CH), 132.8 (C), 135.1 (C), 136.7 (C), 165.0 (CO). MS (EI, 70 eV): m/z (%) 391 (M+2, 10), 389 (M+, 9), 308 (100). Anal. Calcd. for C20H24BrNO2 (390.31): C, 61.54; H, 6.20; N, 3.59%. Found: C, 62.05; H, 6.41; N, 3.64%.

5. CONCLUSIONS :H KDYH HIÂ¿FLHQWO\ V\QWKHVL]HG VRPH S\UUROH GHULYDtives in the presence of zinc oxide nanoparticles under solvent-free conditions in good yields. Zinc oxide nanoparticles as a green, mild and effective catalyst satisfactorily catalyzed the synthesis of these compounds. The catalyst was recyclable and has been reused for three successive runs with little loss of activities.

REFERENCES <DYDUL , *KD]YLQL 0 $]DG / 6DQDHLVKRDU 7 Chin. Chem. Lett., 22 (2011), 1219. %DOPH * Angew. Chem., Int. Ed., 43 (2004), 6238. 'KDNVKLQDPRRUWK\ $ *DUFLD + Chem. Soc. Rev., 43 (2014), 5750. 4. Estevez V., Villacampa M., Menendez J.C., Chem. Soc. Rev., 39 (2010), 4402. 5. Domling A.,Ugi I., Angew. Chem. Int. Ed., 39 (2009), 3168. 77

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6. Lichtenthaler F.W., Acc. Chem. Res., 35 (2002), 728. 7. Litvinov V.P., Russ. Chem. Rev., 72 (2003), 69. 8. Alinezhad H., Tajbakhsh M., J. Chem. Soc., 55 (2011), 238. 9. Moss T.A., Nowak T., Tetrahedron Lett., 53 (2012), 3056. 10. R.A. Sheldon, I. Arends, U. Hanefeld, 2007. Green Chemistry and Catalysis, Wiley-VCH, Weinheim, *HUPDQ\ 11. Bhattacharyya P., Pradhan K., Paul S., Das A.R., Tetrahedron Lett., 53 (2012), 4687. 12. Saeidian H., Abdoli M., Salimi R., C. R. Chim., 16 (2013), 1063.

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13. Bahrami K., Khodaei M.M., Farrokhi A., Synth. Commun., 39 (2009), 1801. 14. Yavari I., Shahvelayati A.S., Malekafzali A., J. Sulfur Chem., 31 (2010), 499. 15. Shahvelayati A.S., Issa Yavari I., Delbari A.S., Chin. Chem. Lett., 25 (2014), 119. 16. Shahvelayati A.S., Adhami, F., Larijani, K., Iranian J. Org. Chem., 3 (2011), 665. 17. Shahvelayati A.S., Iranian J. Org. Chem., 4 (2012), 943. 18. Sabbaghan M., Shahvelayati A.S., Bashtani S.E., Solid State Sci., 14 (2012), 1191.

AUTHOR (S) BIOSKETCHES Ashraf Sadat Shahvelayati, Assistant Professor, Department of Chemistry, Yadegar-e-Imam Khomeini (RAH) Shahre-e rey Branch, Islamic Azad University, Tehran, Iran Email: avelayati@yahoo.com Maryam Sabbaghan, Assistant Professor, Department of Chemistry, Faculty of Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran Solmaz Banihashem, M.Sc., Department of Chemistry, Yadegar-e-Imam Khomeini (RAH) Shahre-rey Branch, Islamic Azad University, Tehran, Iran

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 101-111

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials 6\QWKHVLV DQG &KDUDFWHUL]DWLRQ RI È&#x2013; 0Q22-AgA Zeolite Nanocomposite and its Application for the Removal of Radioactive Strontium-90 (90Sr) Meysam Sadeghi1*, Sina Yekta2, Hamed Ghaedi3, Esmaeil Babanezhad4 1

Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

Department of Chemistry, Faculty of Basic Sciences, Islamic Azad University, Qaemshahr Branch, Qaemshahr, Iran 3

Department of Chemistry, Faculty of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran

Department of Chemistry, Faculty of Basic Sciences, Sharif University of Technology, Tehran, Iran Received: 17 March 2015; Accepted: 20 May 2015

ABSTRACT ,Q WKLV VFLHQWLÂ¿F UHVHDUFK IRU WKH Â¿UVW WLPH WKH UHPRYDO RI UDGLRDFWLYH VWURQWLXP 6U E\ È&#x2013; 0Q22 $J$ ]HROLWH DV D QRYHO QDQRFRPSRVLWH DGVRUEHQW ZDV DFFRPSOLVKHG XQGHU GLIIHUHQW FRQGLWLRQV VXFK DV S+ WHPSHUDWXUH adsorbent amount and the contact time that are examined from drinking water of Ramsar city and monitored via Ultra Low-Level Liquid Scintillation Counting (LSC) technique. Prior to the reaction study, this composite was VXFFHVVIXOO\ SUHSDUHG WKURXJK WKUHH VWHSV Â¿UVW 1D$ QDQR]HROLWH ZDV SUHSDUHG E\ WKH K\GURWKHUPDO PHWKRG 7KHQ VLOYHU LRQV $J+ ZHUH ORDGHG LQ WKH 1D$ QDQR]HROLWH IUDPHZRUN XVLQJ LRQ H[FKDQJH SURFHGXUH DQG VLOYHU Ç¿ QLWUDWH VROXWLRQ DV VLOYHU SUHFXUVRU IRU WKH SUHSDUDWLRQ RI WKH $J$ QDQR]HROLWH )LQDOO\ 0Q22 nanoparticles (NPs) with ZW ZHUH GLVSHUVHG DQG GHSRVLWHG RQ WKH H[WHUQDO VXUIDFH RI $J$ QDQR]HROLWH WKURXJK LPSUHJQDWLRQ PHWKRG IRU WKH SUHSDUDWLRQ RI È&#x2013; 0Q22 $J$ ]HROLWH 7KH V\QWKHVL]HG VDPSOHV KDYH EHHQ FKDUDFWHUL]HG DQG LGHQWLÂ¿HG using Scanning electron microscopy-energy dispersive micro-analysis (SEM-EDX), X-ray diffraction (XRD) and )RXULHU WUDQVIRUP LQIUDUHG )7,5 WHFKQLTXHV 7KH REWDLQHG UHVXOWV GHQRWHG WKDW UDGLRDFWLYH 6U ZDV UHPRYHG DQG DGVRUEHG E\ È&#x2013; 0Q22 $J$ ]HROLWH QDQRFRPSRVLWH XQGHU RSWLPL]HG FRQGLWLRQV LQFOXGLQJ S+ WHPSHUDWXUH Â&#x192;& DQG DGVRUEHQW DPRXQW J DIWHU K ZLWK D \LHOG 7KH PLQLPXP GHWHFWDEOH DFWLYLW\ 0'$ IRU Sr via /6& LQVWUXPHQW ZDV P%T /LW 7KH FRXQWLQJ HIÂ¿FLHQF\ RI /6& V\VWHP ZDV ,W KDV EHHQ HPSKDVL]HG WKDW È&#x2013; 0Q22 $J$ ]HROLWH QDQRFRPSRVLWH KDV D KLJK FDSDFLW\ DQG SRWHQWLDO IRU WKH UHPRYDO RI UDGLRDFWLYH Sr. Keywords: Removal; Radioactive 6U È&#x2013; 0Q22 $J$ =HROLWH 1DQRFRPSRVLWH 'ULQNLQJ ZDWHU

1. INTRODUCTION Strontium-90 (90Sr) is an important component of many nuclear wastes and is a high yield fusion product of uranium-235 (235U). It is relatively short-lived with a half-life of 28.8 years. Yttrium-90 isotope (90Y) is its (*) Corresponding Author - e-mail: meysamsadeghi45@yahoo.com

GHFD\ SURGXFW ZKLFK LV È&#x2022;Ã HPLWWHU ZLWK KDOI OLIH RI hours and decay energy of 2.28 MeV distributed to an electron, an antineutrino and zirconium-90 (90Zr) which is stable. Strontium isotope 90Sr is treated as

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 101-111

RQH RI WKH PRVW GDQJHURXV SURGXFWV RI QXFOHDU ÂżVVLRQ for human beings [1-5]. For this reason its properties and migration in the environment are widely studied. Drinking and fresh waters usually contain many natural radionuclides: Strontium, tritium, radon, radium and uranium isotopes, etc. It is essential to improve rapid removal and decontamination methods for their determination when considering possible nuclear accidents [6-12]. In the last years there has been an increase in the usage of zeolites in different compositions to delete and bury different radio-contaminations [13]. Zeolites are porous crystalline, hydrated alumina silicates of group IA and IIA elements such as sodium, potassium, barium, magnesium and calcium. One of the most important properties of zeolites is their ability to exchange FDWLRQV 7KH W\SH DQG GLVWULEXWLRQ RI FDWLRQV LQĂ&#x20AC;XHQFH the adsorption behavior of zeolites; thus by ion exchange, sorbent with different molecular sieve and adsorption properties can be prepared [14]. Among these three zeolites, A-type molecular sieve zeolite has attracted more attention because of the higher aluminum content within its crystalline structure [15, 16]. The combination of zeolites and metal oxide nanoparticles renders solid catalysts in which the high surface area of nanoparticles and the absorbent capacity provided by zeolites cooperate to increase the HIÂżFLHQF\ RI WKH FDWDO\WLF SURFHVV > @ 7KH PHWKRGV for modifying zeolites are usually by impregnation [18] and ion-exchange [19]. In this research, we have utilized the combination of AgA zeolite as host and MnO2 nanoparticles as guest materials to synthesize an adsorbent catalyst in which the high surface area of nanoparticles and the absorbent capacity provided by WKH ]HROLWH FRRSHUDWLRQ WR LQFUHDVH WKH HIÂżFLHQF\ RI WKH removal process of 90Sr from drinking water. Zeolite A exhibits the LTA (Linde Type A) structure. It has a 3-dimensional pore structure with pores running perpendicular to each other in the x, y, and z planes, and is made of secondary building units 4, 6, 8, DQG 7KH SRUH GLDPHWHU LV GHÂżQHG E\ DQ HLJKW PHPEHU R[\JHQ ULQJ DQG LV VPDOO DW c > @ 7KH SXUSRVH of this research is to investigate the removal of 90Sr by Č&#x2013; 0Q22-AgA zeolite nanocomposite at room temperaWXUH 7KH SUHVHQW ZRUN FRQVLVWV RI WKUHH SDUWV WKH ÂżUVW part includes the preparation of the NaA nanozeolite 102

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using hydrothermal method, the second part includes LWV VWUXFWXUH PRGLÂżFDWLRQ E\ VLOYHU LRQ H[FKDQJH XVing for preparing of AgA nanozeolite. Also, the third SDUW LQFOXGHV LV WKH V\QWKHVL]HG Č&#x2013; 0Q22-AgA zeolite nanocomposite to examine the decontamination of 90 Sr in tap water of Ramsar city. To the best of our knowledge, there are no papers reporting the applicaWLRQ RI Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent used for the removal of 90Sr. Silver cation is the only noble mono-positive cation that forms mononuclear species with appreciable stability in aqueous solution. %HVLGHV VLOYHU LV NQRZQ WR KDYH VWURQJ LQĂ&#x20AC;XHQFH RQ the absorption properties of zeolites. As an important functional metal oxide, manganese dioxide (MnO2) is of the most attractive representations of inorganic materials exhibiting such a rich physical and chemiFDO SURSHUWLHV DQG ZLGH DSSOLFDWLRQV LQ YDULRXV ÂżHOGV such as catalysis, ion exchange, molecular adsorption, biosensor, and energy storage. MnO2 is a very interesting material because of the diversity in its crystalline structure and high manganese valence [21-23].

2. EXPERIMENTAL 2.1. Materials Tetra ethyl ortho silicate (TEOS), tetra methyl ammonium hydroxide (TMAOH), aluminum isopropoxide, sodium hydroxide (NaOH), ethanol, silver nitrate (AgNO3), manganese nitrate hexahydrate (Mn(NO3)2.6H2O), potassium permanganate (KMnO4), acetone, NaOH and HNO3 were purchased IURP 0HUFN 0HUFN 'DUPVWDGW *HUPDQ\ 7KH KLJK capacity cocktail OptiPhase HiSafe-3 (Wallac Oy, Turku, Finland) and double-distilled water were used throughout the work. A strontium standard source with activity of 736.5 Bq/mL was utilized as stock solution that desirable diluted solutions with certain activity were prepared subsequently. Deionized water was used for the preparation of all the solutions. 2.2. Preparation of sodium A-type (NaA) nanozeolite by the hydrothermal method For this work, aluminate and silicate solution were prepared according to the following procedure. 10.5 g of NaOH pellets and 12 g of tetra methyl ammonium

Sadeghi M et al

hydroxide (TMAOH) were together dissolved in 100 mL de-ionized water, in which aluminum isopropoxide (8 g) was added later. The resulting mixture was stirred until a clear solution was formed (solution A). Separately, 16 g of tetra ethyl ortho silicate (TEOS) was added to the rest of the required amount of TMAOH and ethanol solution. The resulting mixture initially formed an emulsion-like state under stirring. However, after 2h of continuous stirring, a homogeneous and clear solution was formed (solution B). Mixing of solutions A and B under stirring was resulted the initial clear solution for synthesis. In order to assure the formation of initially clear solutions free from cloudy particles of gel, the solutions were typically stirred for 3 h at room temperature. Then, hydrothermal crystalOL]DWLRQ RI WKH ]HROLWH ZDV FDUULHG RXW DW Â&#x192;& IRU K Finally, zeolite nanoparticles were recovered from the mother liquor by centrifuge at 10000 rpm for 40min. In order to remove un-reacted materials, the powder was dispersed in DI water by sonication and centrifuged again. This procedure was repeated until the pH of the supernatant decreased to lower than 8. Then WKH SRZGHU ZDV GULHG DW Â&#x192;& RYHUQLJKW 7KH DV V\Qthesized nanozeolitic powders were calcined in oven DW Â&#x192;& LQ K ZLWK WKH KHDWLQJ DQG FRROLQJ UDWH RI Â&#x192;& PLQ WR UHPRYH 70$2+ PROHFXOHV > @ 2.3. Preparation of silver A-type (AgA) nanozeolite by the ion exchange method In a typical procedure, 1.5 g of the synthesized NaA nanozeolite before ionic exchange was calcined at Â&#x192;& IRU K LQ D IXUQDFH IRU H[FOXGLQJ PRLVWHU DQG impurities from the surface. The calcined NaA nanozeolite was then added to a 50 mL of a 0.1 M silver nitrate (AgNO3) solution and the mixture was magnetLFDOO\ VWLUUHG DW Â&#x192;& IRU K WR SHUIRUP LRQ H[FKDQJH process in which Ag+ ions were replaced Na+ ions. The UHVXOWLQJ ]HROLWH ZDV ÂżOWHUHG DQG ZDVKHG ZLWK GHLRQized water to remove the excess salt ions, then dried at Â&#x192;& IRU K )LQDOO\ WKH FOHDQ DQG GU\ QDQR]HROLWH ZDV FDOFLQHG LQ D IXUQDFH DW Â&#x192;& IRU K > @ 3UHSDUDWLRQ RI Č&#x2013; 0Q22-AgA zeolite nanocomposite by the impregnation method The incorporation of MnO2NPs loaded onto AgA QDQR]HROLWH Č&#x2013; 0Q22-AgA) was performed by the

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impregnation method. First, 1 g of AgA nanozeolite was poured into a 20 mL of 1 M (Mn(NO3)2) aqueous solution and stirred for 5 h. Under continuous stirring, 50 mL of a 0.2 M (KMnO4) solution was added to the mixture rapidly. KMnO4 has been known among the strong oxidizing agents [26], so that, the color of the solution immediately turned to dark brown, indicating the formation and precipitation of MnO2NPs through oxidation with KMnO4. The obtained sample was then GULHG DW Â&#x192;& IRU RYHUQLJKW $W ODVW WKH SURGXFW ZDV WUHDWHG E\ FDOFLQDWLRQ DW Â&#x192;& IRU K > @ 7KH ionic equation of the reaction is as follows (1): 3Mn 2 2MnO 4 2H 2 O o 5MnO 2 4H

(1)

2.5. Procedure of radioactive 90Sr removal by Č&#x2013; 0Q22-AgA zeolite nanocomposite For radioactive 90Sr removal study, the amounts of adsorbent (0.5-3 g) was added to 150 mL of the drinking water spiked with 906U DW S+ DQG WKH PL[WXUH were stirred for 1, 2, 3, 6 and 10 h, respectively. After ÂżOWUDWLRQ RI WKH PL[WXUH P/ RI VXSHUQDWDQW VROXWLRQV were analyzed by liquid scintillation spectrometry (LSC) and the activities of the aqueous phase were determined. In LSC, an aliquot of the sample is put into a vial and mixed homogeneously with 15 mL of scintillation cocktail. A shaker was utilized for mixing of cocktail and sample. Samples and cocktail were mixed in 20 mL polyethylene vials, Poly vial. The outside of the vials was cleaned with acetone. All of the polyethylene vials were stored in a cool, dark shield IRU K WR HOLPLQDWH WKH VFLQWLOODWLRQ FRFNWDLO Ă&#x20AC;XRUHVcence. All samples were counted by LSC for 5 h. The initial source activity was 736.5 Bq/mL as mentioned above that 260 ÎźL of it (equal to 60 Bq) was added to solution samples and the relative error of radioactivity measurements did not exceed 2%. 2.6. Characterization technique Physicochemical characterizations of the samples with different analytical techniques were performed. SEM images using a scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEMEDX, HITACHI S-300N). The crystallinity of the samples was determined by X-ray diffraction (XRD) analysis on a Philips X-ray diffractometer using cobalt 103

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Sadeghi M et al

&R UDGLDWLRQ N9 P$ DQG È&#x153; QP 6DPSOHV ZHUH VFDQQHG DW Â&#x192; PLQ LQ WKH UDQJH RI È&#x2122; Â&#x192; 7KH ,5 VSHFWUXP ZDV VFDQQHG XVLQJ D 3HUNLQ Elmer FTIR (Model 2000) in the wavelength range of 400 to 4000 cm-1 with KBr pellets method. An ultralow level liquid scintillation counter (1220 Wallace Quantulus), Perkin Elmer USA) has been used for all measurements. The high-capacity cocktail OptiPhase HiSafe-3 (Wallac Oy, Turku, Finland) and double-distilled water were used throughout the work. A stron-

tium standard source with activity of 736.5 Bq/mL was utilized as stock solution that desirable diluted solutions with certain activity were prepared subsequently.

3. RESULTS AND DISCUSSION 3.1. Scanning electron microscopy (SEM) Analysis The crystalline size and morphology of the as-syn-

(a)

(b)

(c)

(d)

(e)

Figure 1: 6(0 LPDJHV RI WKH V\QWKHVL]HG VDPSOHV D 1D$ E DQG F $J$ G DQG H È&#x2013; 0Q22-AgA with different PDJQLÂ¿FDWLRQ

104

Sadeghi M et al

WKHVL]HG VDPSOHV ZHUH VXUYH\HG WKURXJK PDJQLÂżFDtion by SEM images (Figure 1). Comparison between the morphologies of NaA and AgA nanozeolites and Č&#x2013; 0Q22-AgA zeolite nanocomposite demonstrates the homogeneous morphology of the structures. In addition to this, it shows that the cubic morphology and crystalline size of NaA nanozeolite (Figures 1a) are almost retained with ion exchange process which is indicated by SEM images in Figures 1b and 1c. Although, it can be seen that the crystal structure of Č&#x2013; 0Q22-AgA zeolite nanocomposite (Figures 1d and 1e) slightly changed as compared to support AgA nanozeolite (Figures 1b and 1c). The average crystalline size of zeolites was illustrated to have nano-metric dimensions (less than 100 nm). 3.2. Energy-dispersive X-ray spectrometer (EDAX) analysis Figure 2 give the composition elements present in Č&#x2013; 0Q22-AgA zeolite nanocomposite were investigated by energy dispersive X-ray (EDAX) analysis. In the EDAX spectra, the appeared peaks in the regions of approximately 0.55, 1.15, 1.50, 1.75 and 2.92 and 3.21 keV are corresponded to the binding energies of oxygen (O), sodium (Na), aluminum (Al), silicon (Si) and silver (Ag) respectively that are related to the AgA zeolite. On the other hand, in spectrum (Figure 2b), the appeared two peaks in the regions of 5.86 and 6.24 keV are related to the binding energies of manganese (Mn) which reveals the presence of Mn in WKH FRPSRVLWH 7KHVH UHVXOWV FRQÂżUP FRH[LVWHQFH RI wt% and 19.3 wt% silver and manganese in the prepared sample, respectively.

Figure 2: ('; DQDO\VLV RI WKH V\QWKHVL]HG Č&#x2013; 0Q22-AgA.

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3.3. X-ray diffraction (XRD) analysis In Figure 3, XRD patterns of the under study NaA and $J$ QDQR]HROLWHV DQG Č&#x2013; 0Q22-AgA zeolite nanocomposite are displayed, respectively. As seen from the patterns, the sharp peaks referring to NaA nanozeoOLWH RFFXUUHG DW VFDWWHULQJ DQJOHV Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; DQG Â&#x192; FRUUHsponding to the diffraction planes of (2 2 0), (2 2 2), (4 0 0), (4 2 0), (4 2 2), (4 4 4), (6 4 2), (8 0 0), (6 6 2), (9 3 1) and (10 4 2), which have been crystallized in the cubic system and are in good agreement with those of NaA nanozeolite with molecular formula of Na6[AlSiO4]6.4H2O with reference code (ICDD) of 00-042-0216. NaA zeolite structure was retained even after silver cation exchange in AgA QDQR]HROLWH ,&'' ZLWK PROHFXODU formula of Ag8Al12Si12O48.2H2O. Meanwhile, synthesized MnO2NPs (as guest material) loaded as a 19.3 wt % of unit onto AgA zeolite as the host material, possesses a series of new peaks which were obtained DW Č&#x2122; RI Â&#x192; Â&#x192; Â&#x192; DQG Â&#x192; FRUresponding to the diffraction planes of (1 3 1), (3 0 0), (1 6 0) and (4 2 1), respectively. No characteristic peaks related to the presence of impurities were observed in the patterns during MnO2 loading. These peaks which are illustrated as red points in Figure 2c reveal that MnO2NPs have been dispersed and deposited onto AgA nanozeolite and also indicate a host-guest interaction between AgA framework and MnO213V $ GHÂżQLWH OLQH EURDGHQLQJ RI WKH VFDWWHULQJ pattern in Figure 2c is a demonstration upon which the synthesized MnO2 particles are in nanoscale range. However, a small loss of crystallinity is observed in Figures 2b and 2c associated with the lower intensity RI WKH SHDNV DW Č&#x2122; RI Â&#x192; DQG Â&#x192; 7KLV PD\ occur because of the dealumination process of AgA QDQR]HROLWH DQG Č&#x2013; 0Q22-AgA zeolite nanocomposite and associated with the location of substituted silver and impregnated manganese cations. The Mn4+ ions within the zeolite framework can interact with the aluminate sites more strongly than that of Na+ or Ag+ ions. Totally, it can be concluded that with silver ion exchange in NaA nanozeolite and subsequent loading of MnO2NPs onto AgA nanozeolite, the structure of the zeolites did not change. On the other hand, the ca105

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Sadeghi M et al

pacity of the A-type zeolite to keep the guest species is limited. Consequently, the adsorption of the host catLRQV 6L $O DQG 1D ZLOO VWRS LI WKH FDSDFLW\ LV ÂżOOHG In contrast, the amount of the host species in the AgA nanozeolite increases with increasing the manganese dioxide content. The introduced MnO2NPs were dispersed and deposited on the external surface of AgA nanozeolite, however, due to the relative aggregation during processing of the composite, some particles are too large to perch inside the structure. Hence, high MnO2NPs loading will cause structural damage to the zeolite. The size of the prepared MnO2NPs deposited onto AgA nanozeolite was also investigated via XRD PHDVXUHPHQW DQG OLQH EURDGHQLQJ RI WKH SHDN DW Č&#x2122; Â&#x192; Â&#x192; XVLQJ 'HE\H 6FKHUUHU HTXDWLRQ > @ d

0.94O E cos T

respectively. The particle size obtained from XRD measurement is consistent with the results from the SEM study. 3.4. FTIR study The characterization of the prepared samples along with the A-zeolite precursors was further surveyed by FTIR spectra as plotted in Figure 4. The FTIR spectrum in transmittance mode in Figure 4 shows peaks at 462, 558, 669, 755, 986, 1644 and 3440 cm-1, respectivedy. All of the two as-synthesized typical samples, namely NaA and AgA nanozeolites have peaks around 462 cm-1 and 558 cm-1 which are assigned to the bonding vibration of the insensitive internal TO4 7 6L RU $O WHWUDKHGUDO XQLWV DQG WKH GRXEOH ULQJ external linkage within the A zeolite structure, respectively. The peaks at 669 cm-1 and 755 cm-1 are attributed to external linkage and internal tetrahedral symmetrical stretching vibrations (D6R), respectively. Furthermore, the peaks at 986 cm-1 is corresponded to internal tetrahedral asymmetrical stretching vibrations, and the peaks around 1644 cm-1 and 3440 cm-1 are assigned to Hâ&#x20AC;&#x201C;Oâ&#x20AC;&#x201C;H bending and Oâ&#x20AC;&#x201C;H bonding

(2)

:KHUH G LV WKH FU\VWDO VL]H Č&#x153; LV WKH ZDYHOHQJWK RI ; UD\ VRXUFH Č&#x2022; LV WKH IXOO ZLGWK DW KDOI PD[LPXP ):+0 DQG Č&#x2122; LV %UDJJ GLIIUDFWLRQ DQJOH 8VLQJ WKLV equation, the average particle size for AgA nanozeolite and MnO2NPs are estimated to be 25.7 and 6 nm,

(a)

(b)

(c)

Figure 3: ;5' SDWWHUQV RI WKH V\QWKHVL]HG VDPSOHV D 1D$ E $J$ DQG F Č&#x2013; 0Q22-AgA.

106

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 101-111

(a)

(b)

(c)

Figure 4: )7,5 VSHFWUD RI WKH V\QWKHVL]HG VDPSOHV D 1D$ E $J$ DQG F È&#x2013; 0Q22-AgA.

(hydroxyl groups) vibrations of A zeolite structures, UHVSHFWLYHO\ &RPSDULQJ )LJXUH D DQG E FRQÂ¿UPV that no changes has occurred in the bands of AgA zeolite compared with the original NaA zeolite, which tends to lend further support to the idea that the ion H[FKDQJH PRGLÂ¿FDWLRQ RI 1D$ ]HROLWH E\ VLOYHU LRQ KDV D YHU\ OLWWOH LQÃ&#x20AC;XHQFH RQ WKH FKHPLFDO VWUXFWXUH RI the zeolite framework. On the other hand, Figure 4c illustrates three new peaks related to the synthesized loaded MnO2NPs. The absorption peak at 578 cm-1 is corresponded to Mnâ&#x20AC;&#x201C;O bond. The peaks around 1437 cm-1 and 3625 cm-1 are attributed to Hâ&#x20AC;&#x201C;Oâ&#x20AC;&#x201C;H bending and Oâ&#x20AC;&#x201C;H bonding (hydroxyl groups) vibrations of the nanoparticles, respectively. 3.5. Removal study of 90Sr by MnO2NPs-AgA zeolite composite In order to investigate the removal and adsorption

of radioactive 90Sr, the adsorbent performance of È&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent were evaluated and those progresses were monitored by Ultra low-level liquid scintillation spectroscopy. The various conditions including pH, temperature, adsorbent amount and the contact time were surveyed and optimized. 3.5.1. Effect of pH

2QH RI WKH PRVW VLJQLÂ¿FDQW SDUDPHWHUV WKDW DIIHFW WKH sorption process of radioactive 90Sr is the pH of the considered solution. The role of pH on the adsorption \LHOG RI È&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent was studied via utilizing 90Sr solution of 58.44 %T DW RSWLPL]HG WHPSHUDWXUH Â&#x192;& IRU K $V UHSresented in Figure 5, the adsorption properties of 90Sr was studied at pH ranges of 2.5-10.5 on the removal of 90Sr by nanocomposite adsorbent. To achieve the 107

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LQYHVWLJDWHG LQ WKH WHPSHUDWXUH UDQJH RI Â&#x192;& XQder optimized conditions. Figure 6 illustrates the effect of temperature on the adsorption of 90Sr on the nanocomposite adsorbent surface. As can be seen, the adsorption of 906U RQ WKH Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent decreases as the temperature increases gradually. This is why in high temperatures the formed bonds between 90Sr and active sites of adsorbent will be weak and break down eventually. Figure 5: The curve of 90Sr removal% versus pH.

3.5.3. Effect of amount of adsorbent

PRVW VHOHFWLYLW\ DQG UHPRYDO HIÂżFLHQF\ S+ RI ZDV FRQVLGHUHG IRU WKH IXUWKHU PRGLÂżFDWLRQV DQG DGsorption yield. The solution pH was adjusted via 1M solutions of NaOH and HNO3. Moreover, the sorption equilibrium was reached, the supernatant solution of 90Sr were brought out and introduced to the Ultra Low-Level Liquid Scintillation Counter (LSC). Subsequently, the adsorption and removal value percentage of 90Sr by composite adsorbent was calculated. The interaction of hydrogen ions with an oxygen radical of the zeolite body generates hydroxyl groups and lowers the charge of the matrix, which is accompanied by a decrease in the sorption ability of nanocomposite in relation to 90Sr. Besides, a higher sorption of the radionuclide due to increasing pH shows that in the solution they are in an ionic state. 3.5.2. Effect of temperature

7KH WHPSHUDWXUH LQ ZKLFK WKH H[SHULPHQW IXOÂżOOV LV D VLJQLÂżFDQW SDUDPHWHU WKDW FDQQRW EH RYHU ORRNHG ,Q this research, the adsorption of radioactive 90Sr on the Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent was

Figure 6: The curve of (Â°C).

108

Sr removal% versus temperature

The selection of appropriate amounts of adsorbent is a key role that affects the whole removal process. The adsorption properties of radioactive 90Sr were evaluated at ranges of 0.5-3 g on the removal of 90Sr by composite adsorbent. As it has been shown in Figure 7, with increasing of adsorbent amount, the removal HIÂżFLHQF\ LQFUHDVHV XQWLO WKH SRLQW DIWHU ZKLFK QR PRUH VLJQLÂżFDQW YDULDWLRQV LV VHHQ DQG WKH FXUYH VORSH tend to a linear form which means constant values. Thus, 1.5 g was chosen as the appropriate mass for Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent to fulÂżOO KLJK \LHOG UHPRYDO 3.5.4. Effect of contact time

In order to provide a logical comparison between DGVRUSWLRQ FDSDELOLW\ RI Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent and reaction time, the effect of various contact time intervals on the adsorption of radioactive 90Sr was accomplished. The diversity of adsorption value (%) with shaking time has been explained in Figure 8. Figure 8 represents the reliability of adsorption yield of 90Sr on the nanocom-

Figure 7: The curve of amount.

Sr removal% versus adsorbent

Sadeghi M et al

posite adsorbent to the contact time. As the reaction time increases, the adsorption will increase slightly. The adsorption time was investigated in the range of Âą K DQG /6& DQDO\VLV VKRZHG WKDW WKH UHPRYDO ÂżUVW increased up to 6 h and then remained constant. Thus, to achieve a shorter analysis time 6 h was chosen as optimum value. The obtained results from designed experiment denoted that the sorption procedure was rapid and equilibrium gained quickly after mixing the composite adsorbent with target containing solution. 90 6U XSWDNH RQ WKH Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent may be the cause of exchange of target metallic ion with the other ions presented on the adsorbent surface. The Liquid scintillation counting (LSC) spectra for removal of 90Sr as count versus channel and count versus energy are represented in Figures 9 and 10, respectively. In these spectra, the energetic window A (150-760) includes all the 90Sr spectrum and low energy region of 90Y spectrum. The window B (760-940) includes the high-energy region of the 90Y spectrum. 90Sr analysis of natural water sample from the Ramsar city of Iran has been performed. A typical spectrum of 90Sr in equilibrium with its daughter (90Y)

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 101-111

Figure 8: The curve of 90Sr removal% versus time.

is shown in Figure 8. The strontium activity was calculated using the following equation (3): ASr

(I* $ I %.* $ ) (I* % I %.* % )F<

(3)

60 u ESr u R Sr u Vw

Where is the 90Sr activity in Bq/L; I* $ the gross count rate in region A (channels 150-760) in counts per minute (CPM); I%.* $ the background count rate in region A in CPM; I* % the gross count rate in region B (channels 760-940) in CPM; I%.* % the background count rate in region B in CPM; FY the correction factor taking into account the 90Y contribution to the 90Sr

Figure 9: Liquid scintillation counting (LSC) spectra for removal of 90Sr (count versus channel), (a) before contacting ZLWK SUHSDUHG Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent , b) 1h, (c) 2h, (d) 3h, (e) 6h and (f) 10h.

Figure 10: Liquid scintillation counting (LSC) spectra for removal of 90Sr (count versus energy), (a) before contacting ZLWK SUHSDUHG Č&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent, (b) 1h, (c) 2h, (d) 3h, (e) 6h and (f) 10h.

109

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Table 1: Liquid scintillation counting (LSC) results for removal of nanocomposite adsorbent.

6U E\ È&#x2013; 0Q22-AgA zeolite

Time (h)

CPM(A)

CPM(B)

Activity (Bq/Sample)

Count. Time Min.

MDA (mBq/Sample)

6005.56

2890.41

58.44

100

6.92

3225.81

1471.62

33.46

100

6.92

1850.58

860.50

18.75

100

6.92

819.48

364.92

8.69

100

6.92

598.66

277.06

4.06

100

6.92

632.23

291.23

4.45

100

6.92

window; and FY is derived from where IY,A is the gross count rate of 90Y in region A in CPM and IY,B is the gross count rate of 90Y in region B in CPM. ESr the 90Sr /6& HIÂ¿FLHQF\ 5Sr the chemical recovery factor; Vw the mass of dried sample in kg; The minimum detectable activity (MDA) was evaluated using Currie formula (4) and (5) [32]: MDA(Bq / kg) L d (counts)

Ld (HTQ) 1

(4)

2.71 4.65(BT) 1/ 2

(5)

:KHUH Ä° SDUDPHWHU LV WKH GHWHFWLRQ HIÂ¿FLHQF\ 7 SDrameter is the counting time (s); Q parameter is the sample quantity (kg) and B parameter is also the background count rate (s-1). 7KH UHPRYDO UHDFWLRQ HIÂ¿FLHQF\ SHUFHQWDJH ZDV DOVR calculated using the following equation (6): Re moval(R%)

(A0 A e ) u100 Ae

ferent conditions such as pH, temperature, adsorbent amounts and the contact time were investigated and RSWLPL]HG 7KH UHVXOWV GHQRWHG WKDW È&#x2013; 0Q22-AgA zeolite nanocomposite adsorbent has higher surface area that leads to removal of 906U 7KH S+ WHPSHUDWXUH Â&#x192;& DGVRUEHQW DPRXQW J DQG FRQWDFW WLPH h) were optimized conditions for this process. By consideration of high potential of this composite adsorbent, it can be used for removal of other radionuclide elements which may happen to the environmental water samples.

ACKNOWLEDGEMENT 7KH Â¿QDQFLDO VXSSRUW RI WKH /DERUDWRU\ DW WKH ,PDP Hussein Comprehensive University (IHCU), Tehran is gratefully acknowledged.

(6)

REFERENCES

Where A0 and Ae are the Sr activities in the aqueous phase before and after sorption.

4. CONCLUSIONS ,Q VXPPDU\ È&#x2013; 0Q22-AgA zeolite nanocomposite was successfully synthesized and applied for the removal of radioactive 90Sr ions from drinking water of Ramsar city. The synthesized adsorbent was characterized by SEM/EDX, XRD and FTIR techniques and the removal process followed via Ultra Low-Level Liquid Scintillation Counting (LSC) analysis. The dif110

=KX 6 *KRGV $ 9HVHOVN\ - & 0LUQD $ Schelenz R., Radiochima. Acta, 8 (1990), 195. 2. Chegrouche S., Mellah A., Barkat M., Desalination, 235 (2009), 306. 3. Sebesta F., Motl John A.J., Proceedings of International. Conference on Nuclear Waste Management and Environmental Remediation, Prague, 3 (1993), 871. 4. Mardan A., Ajaz R., Mehmood A., Raza S.M., *KDIIDU $ Sep. Purif. Technol., 16 (1999), 147. 5. Mardan A., Ajaz R., J. Radioanal. Nucl. Chem., 251 (2002), 359.

Sadeghi M et al

6. Szeglowski Z., Constantinescu O., Hussonnois M., Radiochima Acta, 64 (1994), 127. 7. Abadzic, S.A., Ryan, J.N., Environ. Sci. Technol., 35 (2001), 4502. 8. Furhmann M., Aloysius D., Zhou H., Waste Manage, 15 (1995), 485. 9. Blasius E., Klein W., Schon U., J. Radioanal. Nucl. Chem., 89 (1985), 389. 10. Randolph R.B., Appl. Radiat. Isot., 26 (1971), 9. 9DMGD 1 *KRGV (VSKDKDQL $ &RRSHU ( 'DQHVL P.R., J. Radioanal. Nucl. Chem. Art., 162 (1992), 307. *HUVWPDQQ 8 6FKLPPDFN : Radiat. Environ. Biophys., 45 (2006), 187. 13. Alan J.R., John V.B., Amita P., Karl B., J. Contam. Hydrol., 79 (2005), 1. 14. Lonin A.Y., A Krasnopyorova P., Nucl. Phys. Inv., 5 (2004), 82. 15. Anna J., Byeong-Heon J., Hoek M.V., J. Nanopart. Res., 11 (2009), 1795. 16. Rakoczy R.A., Traa Y., Micropor. Mesopor. Mater., 60 (2003), 69. 17. Khatamian M., Alaji Z., Khandar A.A., J. Iran. Chem. Soc., 8 (2011), 44. 18. Hirofumi F. Qi, K., Kenta O., J. Mater. Chem., 9 (1999), 319.

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6KHQ < ) =HUJHU 5 3 'H*X]PDQ 5 1 6XLE S.L., McCurdy L., Potter D.I., OYoung C.L., Science, 23 (1993), 511. 20. Alfaro S., Rodriguez C., Valenzuela M.A., Bosch P., Mater. Lett., 61 (2007), 4655. 21. Cao H., Suib S.L., J. Am. Chem. Soc., 116 (1994), 5334. 22. Jahangirian H., Dig. J. Nanomater. Bios., 8 (2013), 1405. 23. Yamamoto T., Apiluck E., Kim S., Ohmori T., J. Ind. Eng. Chem., 13 (2007), 1142. 24. Yang S., Li Q., Wang M., Micropor. Mesopor. Mater., 87 (2006), 261. 25. Kim S.O., Park E.D., Ko E.Y., US Pat. No. 016 25 57 (2006). 26. Banerjea R., Ind. Med. Gaz., 85 (1950), 214. 27. Richter M., Berndt H., Eckelt R., Schneider M., Fricke R., Catal., 54 (1999), 531. 28. Richter M., J. Catal., 206 (2002), 98. 29. Sadeghi M., Hosseini M.H., J. Nano. Struc., 2 (2013), 439. 30. Sadeghi M., Shahdadi M.R., Toolabi H., Husseini M.H., J. Appl. Chem., 3 (2012), 77. 31. Patterson A., Phys. Rev., 56 (1939), 978. 32. Currie L.A., Anal. Chem., 40 (1968), 586.

AUTHOR (S) BIOSKETCHES Meysam Sadeghi, M.Sc., Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran Email: meysamsadeghi45@yahoo.com Sina Yekta, M.Sc., Department of Chemistry, Faculty of Basic Sciences, Islamic Azad University, Qaemshahr Branch, Qaemshahr, Iran Hamed Ghaedi, Ph.D., Department of Chemistry, Faculty of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran Esmaeil Babanezhad, Ph.D., Department of Chemistry, Faculty of Basic Sciences, Sharif University of Technology, Tehran, Iran

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ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Investigating Output Voltage and Mechanical Stability of a Piezoelectric Nanogenerator Based on ZnO Nanowire Samira Fathi, Tahereh Fanaei Sheikholeslami* Electrical and Electronic Department, University of Sistan and Baluchestan, Zahedan, Iran

Received: 28 March 2015; Accepted: 31 May 2015

ABSTRACT The output of a piezoelectric nanogenerator based on ZnO nanowire is largely affected by the shape of nanowire. In order to obtain mechanically stable nanogenerator with high performance, the investigation of mechanical and electrical characteristics related to the nanowires and materials used in nanogenerators are of great interest DQG VLJQLÂżFDQFH 7KLV SDSHU SUHVHQWV WKH YDULRXV EHKDYLRU RI WKH FRQGXFWLRQ EDQG FDUULHU FRQFHQWUDWLRQ DQG the magnitude and distribution of the piezoelectric potential in cylindrical and conical shape ZnO nanowire (NW) E\ XVLQJ ÂżQLWH HOHPHQW )( PHWKRG ,W LV VKRZQ WKDW V\PPHWU\ UHGXFWLRQ LQ QDQRZLUH VKDSH DQG UHSODFHPHQW the cylindrical NW with the conical NW, results in more advantageous both in terms of mechanical stability and piezoelectric potential. The large variation of the conduction band at the tip of conical nanowire results in receiving a large increase of maximum piezoelectric potential from -70 mv (cylindrical nanowire with radius of 30 nm) to -1750 mv (conical nanowire with tip radius of 5 nm and base radius of 30 nm). It is also shown that the insulating PDWHULDOV ZLWK ORZHU <RXQJÂśV PRGXOXV DQG ORZHU UHODWLYH SHUPLWWLYLW\ DUH WKH EHVW RSWLRQV LQ QDQRJHQHUDWRU GHYLFH fabrication. This numerical study can provide a guideline to design of the piezoelectric nanogenerator with high performance. Keywords: Conical nanowire; Piezoelectric nanogenerator; Piezoelectric potential; Insulating layer; ZnO.

1. INTRODUCTION With the development of technology the size of systems and devices are getting smaller. They often are used in SRVLWLRQV ZKHUH WKHUH LV YHU\ GLIÂżFXOW WR GLUHFWO\ DFFHVV them. Therefore using conventional battery for which must be replaced frequently is not a good option. Finding the low-size, low-weight, independent and sustainable power supply with continuous operation and long

(*) Corresponding Author - e-mail: tahere.fanaei@ece.usb.ac.ir

lifetime is a key challenge for powering [1]. The nature provides numerous potential power sources: light, thermal, mechanical, chemical, and biological energy, which must be converted to electrical energy [2]. Among them, harvesting the mechanical energy directly from the environment, using piezoelectric nanogenerator, is one of the useful and promising

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approaches [3]. The mechanism of the piezoelectric nanogenerator lies in the coupling of piezoelectric and semiconducting properties [4]. Among the known piezoelectric nanomaterials, Zinc Oxide (ZnO) has received broad attention due to three key advantages. First, ZnO exhibits both semiconducting and piezoelectric properties. Second, ZnO is nontoxic and biocompatible. Third, synthesize of the ZnO is easy and low-cost [2]. 7KH ÂżUVW SLH]RHOHFWULF QDQRJHQHUDWRU ZDV LQWURduced by Professor Zhong Lin Wang and Jinhui Song in 2006, which can convert mechanical forces to the voltage ,in nano scale, by bending a vertically grown ZnO nanowire when the atomic force microscopy (AFM)â&#x20AC;&#x2122;s tip swept across the nanowire [2]. Science then, various kinds of nanogenerators has been demonstrated using piezoelectric effect. Recently the integrated nanogenerator based on vertically aligned =Q2 QDQRZLUHV KDV DWWUDFWHG PXFK VFLHQWLÂżF LQWHUHVW because of its much simpler fabrication process than the bending type nanogenerators [5]. Xu et al. have fabricated the vertical nanowire array integrated nanoJHQHUDWRU 9,1* ZKLFK SDFNDJLQJ ZLWK D OD\HU RI polymethyl-methacrylate (PMMA) [4]. In this structure, the output voltage of 80 mV and output current of 6 nA cm-2 can be extracted from the nanogenerator device [4]. The output voltage and current could be greatly enhanced by linearly integrating a number RI 9,1*V > @ 7KH H[LVWHQFH RI 300$ OD\HU FDQ LQcrease the stability and mechanical robustness of the QDQRJHQHUDWRU GHYLFH DQG DOVR LPSURYH WKH HIÂżFLHQF\ of nanogenerator [4]. The current study has been focused on nanogenerator based on vertical ZnO NWs, which is compressed under certain pressure. The overall objective of this paper is to study how conical shape of the ZnO NW can affect the behavior of the free charge carriers and the piezoelectric potential distribution along the nanowire axis. The nanowire with conical structure offers more mechanical stability and more resistance DJDLQVW EUHDNLQJ GHĂ&#x20AC;HFWLRQ DQG WZLVWLQJ WKDQ F\OLQdrical nanowire, which helps to provide a piezoelectric nanogenerator with greater ability to withstand mechanical force. Applying an insulating layer among the ZnO nanowires augments the nanogenerator robustness [4]. Also in this work, a piezoelectric nano114

Fathi S and Fanaei Sheikholeslami T

generator is simulated and investigated numerically. The obtained results show how to improve the nanogenerator performance. Designing the nanogenerator based on the conical nanowires with using the insulating layer can make an extremely stable device with high output.

2. THEORETICAL FRAMEWORK The piezoelectric equations in stress-charge form which represent the electromechanical interactions EHWZHHQ WKH PDWHULDO VWUHVV DQG WKH HOHFWULF ÂżHOG FDQ be expressed by the constitutive relations [6]: T

T C E S e E,

eS NE,

(1)

Where, S and T are the strain and stress tensor respecWLYHO\ ( LV WKH HOHFWULF ÂżHOG YHFWRU DQG ' LV WKH HOHFWULF displacement. CE is the elastic stiffness tensor, e is the piezoelectric constant tensor, N is permittivity tensor, and eT is the transpose of the tensor e. These material parameters are anisotropic tensors which have been taken from the C6V symmetry of the ZnO crystal with wurtzite structure [6]. The ZnO is a piezoelectric material with semiconducting property. Thus in order to model the ZnO nanowire as a piezoelectric semiFRQGXFWRU PDWHULDO ZLWK D VLJQLÂżFDQW DPRXQW RI IUHH electrons, two electrostatic equations should be used. (TXDWLRQ LV D *DXVV V ODZ ZKLFK OLQNV WKH HOHFWULF displacement D to the volume charge density Uv [7]. Mechanical equation (Eq. 3) links the stress T to the applied force F. In Eq. 2, P and n are related to the hole concentration in the valance band and the electron concentration in the conduction band respectively, ND+ is the ionized donor concentration, NA- is the ionized acceptor concentration, and e is electron charge. It is mentioned that for ZnO NW under n-type doping conFHQWUDWLRQ 3 1-A > @ Â&#x2019;.D

Â&#x2019;.T

e(p n N D N A)

(2) (3)

The numerical values related to tensors for the ZnO

Fathi S and Fanaei Sheikholeslami T

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Table 1: ZnO NW parameters with C6V symmetry.

Parameter

Magnitude >*3D@

Parameter

Magnitude [C/m2]

C11 C12 C13 C33 C44 C55

207 117.7 106.1 209.5 44.8 44.6

e15 e31 e33 Č&#x203A; 11 Č&#x203A; 22 Č&#x203A; 33

- 0.45 - 0.51 1.22 7.77 [1] 7.77 [1] 8.91 [1]

nanowire with the C6V hexagonal symmetry are summarized in Table1. The Youngâ&#x20AC;&#x2122;s modulus and Poisson UDWLR DUH UHVSHFWLYHO\ < *3D Č&#x17E; > @

3. RESULTS AND DISCUSSION The open circuit voltage is carried out based on the simulation of ZnO nanowire in static analysis. The geometry includes a ZnO nanowire, approximated DV D F\OLQGHU ZLWK UDGLXV DQG OHQJWK RI 5 QP / QP 7KH =Q2 QDQRZLUH LV DIÂż[HG RQ D JROG substrate with thickness of 40nm. According to the Figure 1a, the geometry is surrounded by free space (air) and the nanowire is normally compressed by a YHUWLFDO IRUFH ) Q1 H[HUWHG DW LWV WRS VHFWLRQ 7KH ZnO nanowire is assumed with moderate conductivity and doped with initial donor concentration ND H C/m3 $W ÂżUVW WKH VLPXODWLRQ LV FDUULHG RXW E\ FRQVLGering the air as an insulating layer, but it is replaced with special dielectric materials to further study the LQĂ&#x20AC;XHQFH RI WKH LQVXODWLQJ OD\HU RQ SLH]RHOHFWULF SRtential. The cylindrical nanowire is compressed by compressive forces, and the piezoelectric potential is distributed along the vertical axis (z-coordinate) of the ZnO nanowire. As seen in Figure 1b, the top part of the nanowire exhibits a negative potential (-66 mv) compared to the bottom part (+29 mv). Although by decreasing cylindrical nanowire diameter the piezoelectric potential has been improved; but structurally, narrow cylindrical nanowires are more fragile. Breaking the symmetry in ZnO nanowire geometry leads to the different procedure of carrier concentration in nanowire.

*HQHUDOO\ E\ DSSO\LQJ WKH IRUFH WKH FRQGXFWLRQ EDQGV DUH GHĂ&#x20AC;HFWHG DW WKH WRS SDUW RI WKH QDQRZLUH charges are depleted from the upper part and created a depletion region at the nanowire tip. The results obtained by varying the nanowire shape from the cylindrical nanowire (30 nm base and tip circular radius) to the conical nanowire (circular base with 30 nm, circular tip with radii ranging from 30 nm to 5 nm) are presented in Figure 2. The behavior of the conduction band level and the charge carrier concentration along the z axis shows that, the depletion region width in the FRQLFDO QDQRZLUHV ZLWK VPDOOHU WLS UDGLXV VLJQLÂżFDQWO\ increases and consequently the negative piezoelectric potential along the nanowire augments. Due to the conical shape of the nanowire, the free charge carrier depletion caused in conical nanowires with lower tip radius, is larger than cylindrical and conical nanowire with large tip radius. The depletion region width is 50 nm for nanowire in cylindrical shape and it reaches to 200 nm in conical nanowire with tip radius of 5 nm.

Figure 1: a) The schematic of the considered ZnO nanowire b) The piezoelectric potential distribution along the cylindrical ZnO nanowire under compressive force F = 100 nm with donor concentration ND= 1e17 C/m3.

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Fathi S and Fanaei Sheikholeslami T

Figure 2: The conduction band and the carrier concentara-

Figure 3: The dissplacement and the piezoelectric potential

tion along the ZnO nanowire in presence of the initial do-

along the ZnO nanowire in presence of the initial donor con-

nor concentration ND= 1e17 C/m . The tip nanowire radius

centration ND=1e17 C/m3. The tip nanowire radius sweeps

sweeps from R= 30 nm to 5nm whereas bottom nanowire

from R=30 nm to 5nm whereas bottom nanowire radius is

radius is R= 30 nm.

R= 30 nm.

By decreasing the nanowire tip radius, the conduction bands provide a strongly high potential barrier. The potential barrier height is 1800 mev for the conical nanowire with tip radius of 5 nm and 60 mev for the cylindrical nanowire. The variations of the nanowire displacement and the piezoelectric potential distribution along the ZnO nanowire for different nanowire tip radius are shown in Figure 3. It is observed that the displacement along the nanowire, especially at the top part of the nanowire is increasing with decreasing the tip radius. In fact there is not a linear relation between the displacement and the applied force, due to the existence of the donor concentration ND H & P3 in ZnO NW. On the other hand, the lack of symmetry in the ZnO nanowire geometry (conical nanowire) leads to the parabolic displacement trend which is appeared especially in the conical nanowire with smaller tip radius. The curves related to the piezoelectric potential exhibit a sigQLÂżFDQW LQFUHDVH LQ SRWHQWLDO DV ZHOO 7KH PD[LPXP SLH]RHOHFWULF SRWHQWLDO LV DSSUR[LPDWHO\ 9 PY at the tip of the conical nanowire (5 nm tip radius) FRPSDUH WR WKH F\OLQGULFDO QDQRZLUH ZLWK 9 PY The doping levels in ZnO, as a semiconducting and SLH]RHOHFWULF PDWHULDO KDYH D ODUJH LQĂ&#x20AC;XHQFH RQ WKH piezoelectric polarization charges in nanowire and on the output potential of the nanogenerator. According to the growth conditions [7], the donor concentration

ranging from ND H & P3 to ND H & P3. So in the following, a comparative investigation is carried out on n-type ZnO nanowire to study the screening effect on the piezoelectric potential in ZnO conical nanowires. The donor concentration ranging from 1' H & P3 WR 1' H & P3. It is found that the maximum piezoelectric potential decreases as doping level increases (Figure 4). The conical structure of nanowire reveals that by increasing the nanowire tip radius and closing the nanowire to the cylindrical

116

Figure 4: The maximum piezoelectric potential at the tip of the ZnO nanowire as a function of the donor concentration from ND=1e15 C/m3 to ND= 1e18 C/m3. The tip nanowire radius sweeps from R=30 nm to 5nm whereas bottom nanowire radius is R=30 nm.

Fathi S and Fanaei Sheikholeslami T

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 113-119

shape, the potential becomes less effective to the donor concentration augmentation. The reduction of the output potential for low donor concentrations is more relevant. )LQDOO\ WKH LQĂ&#x20AC;XHQFH RI WKH GLHOHFWULF PDWHULDO around the nanowire is investigated. For this purpose, the ZnO nanowire is immerged in an insulating layer. The insulating layer not only leads to robust nanogenerator but also protects the nanowires from the short circuits which occur because of the semiconducting properties of ZnO nanowires [8]. The relative dielectric constant as an electrical parameter, Youngâ&#x20AC;&#x2122;s modulus and Poissonâ&#x20AC;&#x2122;s ratio as mechanical parameters of insulating layer between ZnO nanowires, are separately investigated with keeping constant all the other parameters. As shown in Figure 5, the dashed lines indicate the maximum piezoelectric potential at the top surface of insulating layer and solid lines reveals the potential at the tip of nanowire versus the electrical and mechanical parameters for conical nanowire with tip radius equal to 10 nm, and donor concentration ND H & P3. All extracted results from insulating layer surface are few orders of magnitude lower than the nanowire tip. According to the results, the Youngâ&#x20AC;&#x2122;s PRGXOXV DQG UHODWLYH GLHOHFWULF FRQVWDQW KDYH VLJQLÂżcantly affected the potential. The value of Youngâ&#x20AC;&#x2122;s PRGXOXV VSDQV IURP *3D WR *3D WKH SRWHQWLDO decreases from -600 mv to -40 mv; and by varying the relative dielectric constant from 1 to 10, the potential decreases from -700 mv to -195 mv. In contrast,

Figure 5: Variations of piezoelectric potential in respect to Youngâ&#x20AC;&#x2122;s modulus, Poissonâ&#x20AC;&#x2122;s ratio and relative dielectric constant of insulating layer.

WKH HIIHFW RI WKH 3RLVVRQÂśV UDWLR LV OHVV VLJQLÂżFDQW RQ piezoelectric potential and almost becomes negligible. The potential variation is less than 5 mv for the Poissonâ&#x20AC;&#x2122;s ratio ranging from 0.1 to 0.45 (the potential is increased by increasing the Poissonâ&#x20AC;&#x2122;s ratio). )URP WKH DSSOLFDWLRQ SRLQW RI YLHZ ÂżQGLQJ WKH RSWLmal insulating material is of vital importance in nanogenerators output. Dielectric material surrounding the nanowire does not have all ideal terms such as large Youngâ&#x20AC;&#x2122;s modulus, Poissonâ&#x20AC;&#x2122;s ratio and low relative permittivity. Therefore some different dielectric mate-

Table 2: Different insulating materials with various mechanical and electrical parameters.

Parameter Material PVC Nylon PMMA SiO2 *ODVV Si3N4 Al2O3 SiC(6H)

Electrical parameters Relative dielectric constant [1] 2.9 4 3 4.2 4.2 9.7 5.7 9.7

Mechanical parameters Poissonâ&#x20AC;&#x2122;s ratio [1] 0.37 0.4 0.4 0.17

0.3 0.23 0.22 0.45

Youngâ&#x20AC;&#x2122;s modulus >*3D@ 2.9 2 3 70 74 250 400 748 117

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Fathi S and Fanaei Sheikholeslami T

through reducing symmetry in the nanowire shape, more increases the piezoelectric potential compared to the cylindrical nanowire. The undesirable effect of donor concentration on piezoelectric potential is compensated by decreasing the conical nanowire tip radius. 0RUHRYHU WKH LQĂ&#x20AC;XHQFH RI HOHFWULFDO DQG PHFKDQLFDO properties of insulating layer around the ZnO nanowire on improving the nanogenerator device strength and performance is studied. The materials with low Youngâ&#x20AC;&#x2122;s modulus and low relative dielectric constant are the best candidate in order to high pressure transmission to the nanowire and reception of large amount of piezoelectric potential from nanogenerator. Figure 6: The maximum piezoelectric potential at the tip of the ZnO nanowire with conical shape (tip nanowire radius 10 nm) and at the top surface of insulating layer by using the insulating materials with different Youngâ&#x20AC;&#x2122;s modulus. The initial donor concentration is ND= 1e18 C/m3.

rials are considered around the nanowire and simulaWLRQ LV FDUULHG RXW E\ FRQVLGHULQJ WKH LQĂ&#x20AC;XHQFH RI ERWK electrical and mechanical parameters simultaneously. Mechanical and electrical parameters of materials are listed in Table 2. According to simulation results, PVC, Nylon and PMMA, with low Youngâ&#x20AC;&#x2122;s modulus and low relative dielectric constant, are better suited for a nanogenerator device than the other insulating materials tested. The greater part of the applied forces can be transmitted to the nanowires, so more piezoelectric potential transfer to the surface of the nanogenerator through the insulating layer with low Youngâ&#x20AC;&#x2122;s modulus. The maximum piezoelectric potential variations at the tip of nanowire versus mechanical and electrical parameters of insulating layer are more important than the potential variations exerted from insulating layer (nanogenerator output) surface (Figure 6).

4. CONCLUSIONS In present paper, the strong dependence of the piezoelectric potential on the nanowire shape is investigated. The different behaviors of free charge carriers in vertically compressed conical n-type ZnO nanowire,

118

ACKNOWLEDGEMENT The authors would like to gratefully acknowledge the support of Ministry of Science, Research & Technology of I.R. Iran (project number: 214).

REFRENCES 1. Z.L. Wang, 2011. Nanogenerators for Self-powered Devices and Systems *HRUJLD ,QVWLWXWH RI Technology, Atlanta, USA. 2. Wang Z.L., Song J., Science, 312(5) (2006), 242. 3. Hu Y., Zhang Y., Xu C., Lin Long., L Snyder, R., Wang, Zhong L., Nano Lett., 11(6) (2011), 2572. 4. Xu Sh., Qin Y., Xu C., Wei Y., Yang R., Wang Zhong L., Nat Nanotechnol., 5 (2010), 366. :DQJ = 3DQ ; < +H +X < *X + :DQJ < Adv. Mater. Sci. Eng., 2015 (2015), 1. *DR < Nano Lett., 7(8) (2007), 2499. *DR < :DQJ =KRQJ / Nano Lett., 9(3) (2009), 1103. :DQJ = / =KX * <DQJ < :DQJ 6 3DQ & Mate. Today, 15(12) (2012), 532.

Fathi S and Fanaei Sheikholeslami T

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 113-119

AUTHOR (S) BIOSKETCHES Samira Fathi, M.Sc., Electrical and Electronic Department, University of Sistan and Baluchestan, Zahedan, Iran Tahereh Fanaei Sheikholeslami, Assistant Professor, Electrical and Electronic Department, University of Sistan and Baluchestan, Zahedan, Iran Email: tahere.fanaei@ece.usb.ac.ir

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ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Cubic NiO Nanoparticles: Synthesis and Characterization Aliakbar Dehno Khalaji1*, Debasis Das2, JesĂşs S. Matalobos3, Fatemeh Gharib4 1

Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran & Cubane Chemistry of Hircane Co (CCH), Gorgan, Iran

Department of Chemistry, The University of Burdwan, Burdwan, West Bangal, India

'HSDUWDPHQWR GH 4XLPLFD ,QRUJDQLFD )DFXOWDGH GH 4XLPLFD $YGD 'DV &LHQFLDV V Q Santiago de Compostela, Spain 4

Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran Received: 10 January 2015; Accepted: 14 March 2015

ABSTRACT In this paper, cubic nickel oxide nanoparticles were successfully prepared by solid-state thermal decomposition of nickel(II) macrocyclic Schiff-base complex at 450Â°C for 3 h without employing toxic solvent or surfactant and complicated equipment. nickel(II) macrocyclic Schiff-base complex was synthesized by the reaction of 1,2-bis(2formyl-3-methoxyphenyl)propane, NiCl2Â&#x2021; +2O and 1,3-phenylenediamine in methanol at room temperature and characterized by elemental analyses and FT-IR spectroscopy. The as prepared NiO nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD pattern result shows that the synthesized NiO nanoparticles are pure and single phase. The SEM and TEM results show the morphology of the as prepared NiO nanoparticles is almost cubic shape with the average size between 20-150 nm. On the basis of the above results, other transition metal macrocyclic Schiff base complexes are therefore potentially capable of forming metal oxide nanoparticles. Keywords: NiO Nanoparticles; Nickel(II) macrocyclic; Characterized; Schiff base; Thermal decomposition.

1. INTRODUCTION The synthesis of macrocyclic Schiff base compounds containing nitrogen and oxygen donor atoms have received much attention in recent years because their potential applications in fundamental and applied sciences [1-3] and in the area of transition metal coordination chemistry [4-7]. The formation of nickel(II) macURF\FOLF FRPSOH[HV GHSHQGV VLJQLÂżFDQWO\ RQ WKH QDWXUH

(*) Corresponding Author - e-mail: alidkhalaji@yahoo.com

of ligand, such as the dimension of internal cavity, the rigidity and its donor atoms [4, 8-10]. Nickel oxide is considered a p-type semiconductor with wide band gap energy of about 3.6-4 eV and is candidate for supercapacitor [11-13], lithium ion batteries [14, 15], photocalatysis [16], electrochromic [17] and magnetic properties [18]. Until now, many different methods such as

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 59-64

sol-gel [11], calcinations [12, 14], chemical bath deposition [13], spray pyrolysis [15], solvothermal [19] and solid-state thermal decomposition [20-25] used for the preparation of nickel oxide nanoparticles. But, solid-state thermal decomposition method is one of the simplest, lowest cost (low energy consumption) and environment-friendly method (no need for solvent) for preparing pure nickel oxides nanoparticles [20-24]. Recently, Farhadi et al. prepared nickel oxide nanoparticles by solid-state thermal decomposition of octahedral nickel(II) complexes as new precursors at various temperature [23, 24]. In this work, and as a part of the ongoing study on preparation of nickel oxide nanoparticles by solidstate thermal decomposition of Schiff base complexes [21,22], we wish to report the preparation of nickel oxide nanoparticles from nickel(II) macrocyclic Schiff base complex (Figure 1). To the best of our knowlHGJH WKLV LV WKH ÂżUVW UHSRUW RQ WKH V\QWKHVLV RI QLFNHO oxide nanoparticles with nickel(II) macrocyclic Schiff base complexes.

2. EXPERIMENTAL 2.1. Material and characterization All reagents and solvents for synthesis and analysis were commercially available and used as received ZLWKRXW IXUWKHU SXULÂżFDWLRQV ELV IRUP\O PHthoxyphenyl)propane was prepared by the reaction of 3-methoxysalicylaldehyde and 1,3-dibromopropane in the presence of K2CO3 at 80ÂşC according to the literature [25]. Elemental analyses were carried out using a Heraeus CHN-O-Rapid analyzer, and results agreed with calculated values. X-ray powder diffraction (XRD) pattern was record-

Dehno Khalaji AA et al

ed on a Bruker AXS diffractometer D8 ADVANCE ZLWK &X .ÄŽ UDGLDWLRQ ZLWK QLFNHO EHWD ÂżOWHU LQ WKH UDQJH Č&#x2122; Â&#x192; Â&#x192; )RXULHU 7UDQVIRUP ,QIUDUHG VSHFtra were recorded as a KBr disk on a FT-IR Perkin. Elmer spectrophotometer. The transmission electron microscopy (TEM) images were obtained from a JEOL TEM 1400 transmission electron microscope with an accelerating voltage of 120 kV while the scanning electron microscopy (SEM) images were obtained from a Philips XL-30E SEM. 2.2. Preparation of nickel(II) macrocyclic Schiff base complex To a stirred solution of 1,2-bis(2-formyl-3-methoxyphenyl)propane (2 mmol) and NiCl2Â&#x2021; +2O (2 mmol) in methanol (50 mL) was added dropwise 1,3-phenylenediamine (2mmol) in methanol (10 mL). After the addition was completed, the stirring was continued for 2 h. The microcrystalline powder of the FRPSOH[ ZDV ÂżOWHUHG DQG ZDVKHG ZLWK FROG PHWKDnol and then dried in air for 2 days. Anal. calcd for C25H24N2NiO2Cl2Â&#x2021; +2O: C, 54.58; H, 5.13; N, 5.09%; Found C, 54.49; H, 5.15; N, 5.01%. FT-IR (KBr, cm1): 3375 (H22 & 1 & & DURmatic). 2.3. Preparation of NiO nanoparticles Microcrystalline powder of the mononuclear nickel(II) macrocyclic Schiff base complex (about 0.5 g) is loaded into a platinum crucible and then placed in the electrical furnace and heated, at a rate of 10ÂşC/min in air, up to 450ÂşC. After 3.5 hours, the resulting nanoparticles of NiO are washed with ethanol - at least three times - to remove eventual impurities, and then dried in air for 2 days. FT-IR (KBr pellet, cm-1): 3412, 1627(H2O), 459 (Ni-O).

Figure 1: The chemical structure of nickel(II) macrocyclic Schiff base complex and the preparation of NiO nanoparticles.

Dehno Khalaji AA et al

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 59-64

(a)

(b)

Figure 2: FT-IR spectra of complex (top) and NiO nanopartilces (bottom).

3. RESULTS AND DISCUSSION 3.1. Synthesis The mononuclear nickel(II) macrocyclic Schiff base complex was synthesis by methanolic solution of nickel(II) chloride, 1,2-bis(2-formyl-3-methoxyphenyl)propane and 1,3-phenylenediamine in molar ratio 1:1:1 at room temperature for 2 h and characterized by FT-IR and elemental analyses (CHN). The proposed structure of the complex is presented in Figure 1, and is similar to the nickel(II) macrocyclic complexes that reported by Ilhan and co-workers [4]. 3.2. FT-IR spectrum The FT-IR spectra of complex and its decomposition SURGXFW DW & DUH VKRZQ LQ )LJXUH ,Q WKH )7 IR spectrum of complex, the characteristic band of

the H2O molecules is observed at 3394 cm-1, while WKH FKDUDFWHULVWLF EDQG RI & 1 DQG & & JURXSV DUH observed at 1624 and 1578-1476 cm-1, respectively, FRQ¿UPHG WKH FRRUGLQDWLRQ RI PDFURF\FOH 6FKLII EDVH ligand to Ni(II) ion. These bans disappeared in the FTIR spectrum of NiO product. In the FT-IR spectrum of NiO products (Figure 2), the broad bonds peaks at 3537 (hydroxyl group) and 1654 cm-1 (H-OH bending vibration), are due to adsorbed water molecules on the external surface of NiO nanoparticles during handling to record the spectrum. The characteristic wide peak at 462 cm-1 was attributed to the Ni-O stretching vibration of spinal structure of NiO [19]. 3.3. XRD analysis The phase composition of NiO products has been characterized by powder XRD analysis (Figure 3). The 61

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Table 1: The crystal sizes of NiO nanoparticles calculated based on the FWHM of all diffraction peaks.

Pos. > Č&#x2122;@

d-spacing [A]

Rel. Int. [%]

Height [cps]

FWHM > Č&#x2122;@

Crystallite Size [nm]

37.256(2)

2.41155

54.46

287.08

0.244616

24.2

43.290(2)

2.08834

100.00

527.19

0.239636

25.2

62.865(4)

1.47709

30.02

158.24

0.339064

19.4

75.376(9)

1.25998

11.33

59.72

0.397633

17.8

79.33(2)

1.20684

7.61

40.13

0.314134

23.2

XRD pattern reveals diffraction peaks were observed DW DERXW Č&#x2122; YDOXHV RI Â&#x17E; Â&#x17E; Â&#x17E; Â&#x17E; DQG Â&#x17E; WKDW DUH assigned to the (111), (200), (220), (311) and (222) crystal planes of the pure nickel oxide nanocrystalline phase, respectively. All the diffraction peaks are in good agreement with the JCPDS card No. 47-1049 of the NiO nanoparticles with space group Fm3m [25, @ 7KLV UHVXOW FRQÂżUPV WKDW WKH FRPSOH[ LV GHFRPSRVHG FRPSOHWHO\ LQWR WKH 1L2 DW Â&#x192;& 7KH ;5' result is in good agreement with the FT-IE result. No characteristic peaks of other impure phase, like NaOH, could be detected, indicating that the product is highly pure NiO. The crystal sizes of the NiO nanoparticles based on the FWHM of the all diffraction peaks are in the range of 17.8 to 25.2 nm (Table 1). 3.4. SEM and TEM images The morphology of the NiO products was investigated by SEM (Figure 4) and TEM (Figure 5). From the SEM micrograph, it was observed that the nanoparticles were similar and uniform sizes but these particles were agglomerates.

Figure 3: XRD pattern of NiO nanoparticles prepared.

The TEM sample was prepared by dispersing the powder in ethanol by ultrasonic vibration. The uniform of the NiO nanoparticles have plate-like shapes with weak agglomeration. The nanoparticles of NiO with an average size about 15-25 nm are seen inside TEM LPDJH 7KH 6(0 DQG 7(0 UHVXOWV FRQÂżUP WKDW WKH mononuclear nickel(II) macrocyclic Schiff base complex is suitable precursor for the preparation of NiO

Figure 4: SEM image of NiO nanoparticles prepared.

Figure 5: TEM image of NiO nanoparticles prepared.

Dehno Khalaji AA et al

nanoparticles.

4. CONCLUSIONS In this paper, we used mononuclear nickel(II) macrocyclic Schiff base complex as new precursor for preparation of NiO nanoparticle by solid-state thermal decomposition. The NiO products obtained at 450ÂşC for 3.5 h. The crystalline structure and morphology of the synthesized NiO nanoparticles have been studied by FT-IR, XRD, SEM and TEM. The absence of any residual complex traces or other phases indicated the as-prepared NiO samples to have high purity. The results (XRD and TEM) shows the formation of NiO nanoparticles with almost plate shape with anaverage size ranges from 20-150 nm.

ACKNOWLEDGEMENT 7KH ÂżQDQFLDO VXSSRUW IURP WKH *ROHVWDQ 8QLYHUVLW\ and CCH are gratefully acknowledged.

REFERENCES 1. Kumar D.S. and Alexander V., Polyhedron, 18 (1999), 1561. 7DPEXULQL 6 9LJDWR 9 *DWRV 0 %HUWROR / DQGCasellato U., Inorg. Chim. Acta, 359 (2006), 183. 3. Borisova N.E., Reshetova M.D. and Ustynyuk Y.A., Chem. Rev., 107 (2007), 46. 4. Ilhan S., Temel H., Kilic A. and Tas E., Trans. Met. Chem., 32 (2007), 1012. 5. Yilmaz I., Ilhan S., Temel H. and Kilic A., J. Incl. Phenom. Macrocycl. Chem., 63 (2009), 163. 6. Ilhan S. and Temel H., Ind. J. Chem. A., 47 (2008), 378. 7. Ilhan S. and Temel H., Trans. Met. Chem., 32 (2007), 1039. 8. Khandar A.A., Hosseini-Yazdi S.A., Khatamian M. and Zarei S.A., Polyhedron, 29 (2010), 995.

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9. Salavati-Niasari M. and Amiri A., Trans. Met. Chem., 31 (2006), 157. 10. Al-Radadi N.S., Al-Ashgar S.M. and Mostafa M.M., J. Incl. Phenom. Macrocycl. Chem., 69 (2011), 157. 11. Kim S.I., Lee J.S., Ahn H.J., Song H.K. and Jang J.H., ACS App. Mater. Interfaces, 5 (2013), 1596. 12. Vijayakumar S., Nagamuthu S. and Muralidharan * ACS App. Mater. Interfaces, 5 (2013), 2188. 13. Wu C.H., Deng S.X., Wang H., Sun Y.X., Liu J.B. and Yan H., ACS App. Mater. Interfaces, 6 (2014), 1106. 14. Pan J.H., Huang Q., Koh Z.Y., Neo D., Wang X.Z. and Wang Q., ACS App. Mater. Interfaces, 5 (2013), 6292. 15. Choi S.H. and Kang Y.C., ACS App. Mater. Interfaces, 6 (2014), 2312. 16. Rakshit S., Chall S., Mati S.S., Roychowdhury A., Moulik S.P. and Bhattacharya S.C., RSC Advances, 3 (2013), 6106. 17. Dalavi D.S., Devan R.S., Patil R.S., Ma Y.R., Kang 0 * .LP - + DQG 3DWLO 3 6 J. Mater. Chem. A., 1 (2013), 1035. 18. Farzaneh F. and Haghshenas Kashanie S., J. Cer. Process Res., 14 (2013), 673. 19. Kalam A., Al-Shihri A.S., Shakir M., El-Bindary $ $ <RXVHI ( 6 6 DQG 'X * Synth. React. Inorg. Met.Org. Chem., 41 (2011), 1324. 20. Mehdizadeh R., Sanati S. and Saghatforoush L.A., Synth. React. Inorg. Met. Org. Chem., 43 (2013), 466. 21. Khalaji A.D., J. Clust. Sci., 24 (2013), 189. 22. Khalaji A.D., J. Clust. Sci., 24 (2013), 209. 23. Farhadi S. and Roostaei-Zaniyani Z., Polyhedron, 30 (2011), 1244. 24. Farhadi S. and Roostaei-Zaniyani Z., Polyhedron, 30 (2011), 971. 25. Sun W., Chen L., Meng S., Wang Y., Li H., Han Y. and Wei N., Mat. Sci. Semicon. Proc., 17 (2014), 129. 26. Xia Q.X., Hui K.S., Hui K.N., Hwang D.H., Lee S.K., Zhou W., Cho Y.R., Kwon S.H., Wang Q.M. DQG 6RQ < * Mater. Lett., 69 (2012), 69.

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AUTHOR (S) BIOSKETCHES Aliakbar Dehno Khalaji, Assistant Professor, Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran &Cubane Chemistry of Hircane Co (CCH), Gorgan, Iran Email: alidkhalaji@yahoo.com Debasis Das, Associate Professor, Department of Chemistry, The University of Burdwan, Burdwan, West Bangal, India JesĂşs S. Matalobos, Associate Professor, Departamento de QuimicaInorganica, Facultade de Quimica, $YGD 'DV &LHQFLDV V Q 6DQWLDJR GH &RPSRVWHOD 6SDLQ Fatemeh Gharib, Bs.C. Student, Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran

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ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Toxicity Comparative of CdSe:ZnS Quantum Dots on Testis, and Liver in Adult Mice Akram Valipoor1*, Gholamreza Amiri2, Jafar Taheri3, Mehdi Abasi4, Amin Mirzakhani5 1

Physiology Department, Basic Sciences Faculty, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran

Department of Physic, Falavarjan Branch, Islamic Azad University, Isfahan, Iran 3 4

Department of Chemistry, Islamic Azad University, Shahrekord, Iran Department of Statistics, Islamic Azad University, Shahrekord, Iran

Department of Mechanical Engineering, Payame Noor University, PO BOX 19395-3697 Tehran, Iran Received: 21 January 2015; Accepted: 25 March 2015

ABSTRACT 4XDQWXP GRWV DUH QHZ W\SHV RI Ã&#x20AC;XRUHVFHQW PDWHULDOV IRU ELRORJLFDO ODEHOLQJ $V D UHVXOW 4'V WR[LFLW\ VWXG\ LV DQ essential requirement for future clinical applications. Therefore, the cytotoxic CdSe:ZnS quantum dots effects on some organs in mice are presented in this study. In this work, 10, 20 and 40 mg/kg doses of CdSe:ZnS quantum dots were injected to 32 adult male mice. Structural and optical properties of quantum dots were studied by XRD. 7KH WHVWLV DQG OLYHU ZHLJKW RI YDULRXV JURXSV ZHUH DQDO\]HG XVLQJ 6366 SURJUDP RQH ZD\ $129$ WHVW DQG histological changes in testis, liver tissues were analyzed by Light microscopy. Testis tissue showed high toxic HIIHFW LQ PJ NJ GRVH $OVR KLVWRORJLFDO VWXG\ RI OLYHU WLVVXH VKRZHG GHJHQHUDWLRQ RI KHSDWRF\WH F\WRSODVP nuclear matters and sinusoidal dilation in dose-dependent manner in comparable to control groups but the lobular DUFKLWHFWXUH LV ODUJHO\ PDLQWDLQHG LQ DQG PJ NJ GRVHV 7KH ERG\ ZHLJKW GLG QRW FKDQJH VLJQLÂ¿FDQWO\ LQ DQ\ RI WKH &G6H =Q6 WUHDWHG JURXSV 7KH WHVWLV ZHLJKW 7: GHFUHDVHG VLJQLÂ¿FDQWO\ LQ PLFH WKDW UHFHLYHG PJ kg CdSe:ZnS QDs and liver weight in the case of mice treated with 20, 40 mg/kg CdSe:ZnS QDs were increased VLJQLÂ¿FDQWO\ $FFRUGLQJ WR WKH GLIIHUHQFHV WKH WR[LFLW\ RI TXDQWXP GRW RQ WHVWLV DQG OLYHU WLVVXHV LQ DGXOW LW VHHPV that various organs have different responses to quantum dots toxicity. Keywords: Quantum dots; CdSe:ZnS; Testis; Liver; Toxicity.

1. INTRODUCTION 2UJDQLF G\HV KDYH EHHQ ZLGHO\ XVHG DV Ã&#x20AC;XRURSKRUHV in biomedical imaging and detection. However, organic dyes are generally vulnerable to the physiological environment and are quickly photobleached under normal imaging conditions. Also they are not good for multicolor imaging because of two inherent properties (*) Corresponding Author - e-mail: Valipoor.akram@gmail.com

(1) organic dyes have relatively broad emission spectra and hence result in the signal overlap from different dyes; and (2) one organic dye can only be suitably excited by the lights within a certain narrow wavelength range and it thus needs nearly the same numbers of excitation light sources as the dyes used. [1-3], But semi-

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conductor quantum dots (QDs) are tiny light-emitting particles on the nanometer scale, and are emerging as D QHZ FODVV RI Ă&#x20AC;XRUHVFHQW ODEHOV IRU ELRORJ\ DQG PHGLFLQH LQ FRPSDULVRQ ZLWK RUJDQLF G\HV DQG Ă&#x20AC;XRUHVFHQW proteins [1, 3, and 4]. Inorganic quantum dots are usually bright (20â&#x20AC;&#x201C;80% TXDQWXP HIÂżFLHQF\ DQG VWDEOH XQGHU UHODWLYH KDUVK environments [5-7]. The absorption spectra of quantum dots are continuous, and the emissions spectra are narrow (typically 20â&#x20AC;&#x201C;30 nm for FWHM, full width at half maximum of the emission spectrum). Excitationâ&#x20AC;&#x201C; emission matrix (EEM) reveals that quantum dots always emit the same lights no matter what excitation wavelength used. Therefore, the entire different emission colors from quantum dots can be seen at the same time by only one laser excitation source. The emission intensity of quantum dots could also be used as a variant for imaging because of their excellent levels could determine (106-1) nucleic acid or protein sequences [7-9]. The long-term multiplexed biomedical imaging has recently become one of the hottest research topics [7-10]. Successful use of QDs has been reported in various PHGLFDO ÂżHOGV EXW WKH LPSRUWDQW SRLQW LV WKH KLJK WR[icity of core compounds of these nanoparticles which are composed of heavy metals such as cadmium and thallium [7, 11, and 12]. Therefore the study of the toxic effect of QDs is very important for their biological use and it is a decisive factor in their wide use in medicine, hence much attention has been paid to them in recent years [13, 14]. If it would determine that the combination of heavy metal has a minor role in the cytotoxicity of QDs, they have a good chance for being used as contrast agents in clinical use [11]. Considering at present there is relatively little work on toxicity of QDs especial in vivo and lack of any previous study in this category, In this study, cyctoxic HIIHFW RI &G6H =Q6 KDV EHHQ VWXGLHG IRU ÂżUVW WLPH RQ testis, epididymis, liver tissues histopathology and testis , liver weight of animals.

2. MATERIALS AND METHOD 2.1. Methods of producing quantum dots Nanoparticles were synthesized by chemical precipi66

Valipoor A et al

tation method. For this purpose, three solutions of cadmium chloride (CdCl2.4H2O), mercaptoethanol (ME) and sodium selenite (Na2SeO3.5H2O) were prepared in the distilled deionized water, under vigorous stirring DOO IURP 0HUFN &RPSDQ\ $W ÂżUVW &G&O2 solution was poured into a three spout balloon container and in the meanwhile, ME solution was added to the same balloon. Finally, sodium selenite solution was added to the balloon by the same way under nitrogen (N2) atmosphere control condition. The resulting solution was mixed with deionized water and then was centrifuged in order to remove any impurity aggregate. Then, the precipitated sample was dried at room temperature. All processes were done at room temperature [15]. The crystal structure and optical properties of QDs were characterized by XRD (X-ray Diffraction, %UXNHU ' $'9$1&( Č&#x153; QP &X .ÄŽ UDGLDWLRQ and UV-Vis spectrophotometer (Ultra Violetâ&#x20AC;&#x201C;Visible, UV-2600 Shimadzu, Japan). STM (Scanning Tunneling Microscope, NATSICO Iran) were used for investigation of particle size distribution [15]. 7KH UHVXOWV RI GRVH ÂżQGLQJ VWXG\ $FFRUGLQJ WR RXU UHFHQW ÂżQGLQJV WKHUH ZDV QR UHYLHZ of QDs in vivo toxicity. The 125, 250, and 500 mg/kg per kg of body weight doses were selected on the baVLV RI WKH ÂżQGLQJV RI LQ YLWUR VWXGLHV SDUWLFXODUO\ WKH VWXG\ %\ 0LQJ 6KX +VLHK ,Q WKH ÂżUVW VWDJH &G6H and CdSe:ZnS nanoparticles were prepared in normal saline solution and were intraperitoneally injected to 36 mice. All mice died in less than 24 hours after the LQMHFWLRQ 7KH UHPDUNDEOH ÂżQGLQJ ZDV WKDW LQ VSLWH RI in vitro results, including high control of CdSe QDs cytotoxicity by ZnS cover in embryonic culture environment, in vivo use of ZnS cover increased toxicity of CdSe and the rats showed greater responses to CdSe:ZnS compared to CdSe. So, the CdSe:ZnS -treated mice died within a shorter interval. Also some rats died almost immediately after the injection. In the next step DMSA-coated CdSe nanoparticles were injected to 16 mice intraperitoneally at 125 and 250 mg/kg doses. The results showed that 100% of the mice injected with DMSA-coated CdSe at 250 mg/kg dose and 75 to 80% of mice injected with DMSA-coated CdSe at 125 mg/kg dose died within one week. In the

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third step, CdSe and CdSe:ZnS were intraperitoneally injected to 32 mice at 100 and 75 mg/kg doses. In CdSe:ZnS (at 100 and 75 mg/kg doses) groups, respectively 83% and 50% of mice and in CdSe (at 100 and 75 mg/kg doses) groups, respectively 66% and 50% of mice died within one week. Finally, were selected and injected to 24 mice. In CdSe groups 0% of mice died during 20 days at all three doses and in CdSe:ZnS groups 0, 12.5% and 20% of mice died at respectively 10, 20 and 40 mg/kg doses. According WR WKH REWDLQHG UHVXOWV LQ GRVH Â¿QGLQJ VWXG\ PJ kg dose was determined as a safe dose and 20 and 40 mg/kg doses were determined as doses with toxicity effects.

'LIIHUHQFHV ZDV FRQVLGHUHG VLJQLÂ¿FDQW DW S S

2.3. Breeding and treatment of animals Some male mice (about 60-70 days old) per were kept for 10 days in natural day light and temperature 22 Â&#x192;& LQ RUGHU WR DGDSW WKHLU OLIH F\FOH WR WKLV HQYLURQment. Then, 32 adult male mice were divided randomly in 4 groups in each group of 8 sample: control, and treated with 10, 20 and 40 mg/kg doses of CdSe:ZnS QDs. CdSe:ZnS nanoparticles were prepared in normal saline solution and single-dose were injected intraperitoneally and Control group received only normal saline.

3.2. Body, testis and liver weight changes 7KH ERG\ ZHLJKW GLG QRW FKDQJH VLJQLÂ¿FDQWO\ LQ DQ\ RI the CdSe:ZnS treated groups (Figure 1). The testicular weight in the case of mice treated with 10, 20 mg/kg CdSe:ZnS QDs were similar to control group and no VLJQLÂ¿FDQW FKDQJH ZDV IRXQG LQ UHODWLYH WHVWLV ZHLJKWV EXW WKH WHVWLV ZHLJKW 7: GHFUHDVHG VLJQLÂ¿FDQWO\ LQ mice that received 40 mg/kg CdSe:ZnS QDs (Figure 2) parallel with histological changes in mice testis in this group. Also weight liver in mice that received 10 mg/kg CdSe:ZnS QDs were similar in treated group, FRQWURO DQG WKHUH ZDV QR VWDWLVWLFDOO\ VLJQLÂ¿FDQW GLIferences between control group and mice treated with 10 mg/kg CdSe:ZnS. But liver weight in the case of mice treated with 20, 40 mg/kg CdSe:ZnS QDs were

2.4. Tissue preparing 10 Days after CdSe:ZnS injection, 32 adult male mice following measurement of their bodies weight were anesthetized and liver and testis organs were rapidly FXW ZHLJKWHG DQG SUHVHUYHG LQ IRUPDOGHK\GH Â¿[Dtive. Five micron slides were dehydrated and prepared LQ SDUDIÂ¿Q 7KHQ WKH VOLGHV ZHUH FRORXUHG XVLQJ KHmatoxylin-eosin staining method. Liver tissue histopathology, morphological structure of seminiferous tubes, and average number of spermatogonia, spermatocytes, spermatids, and matured sperms in testis and epithelial height, Connective tissue, Smooth muscle and sperm density were measured. 2.5. Statistical analysis Data (testis, liver weight and the number of cells in seminiferous tubes of various groups) were analyzed using SPSS 16 program (by one way ANOVA). Statistical analysis Data were represented as means Â± S.E.

3. RESULTS AND DISCUSSION 3.1. The results of XRD, STM and UV-Vis absorption spectrum The structure of the CdSe:ZnS QDs was investigated by XRD. The sample has a single phase and also a cubic crystal structure. The mean size of the particles was determined by Debye-Scherer formula. It was calculated as being of 2.4 nm for QDs. The size was determined around 3 nm from STM photograph (12).

Figure 1: Mean comparison of body weight in adult group 10 days after injection (**p<0.01).

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Figure 2: Mean comparison of testis weight in adult group

Figure 3: Mean comparison of liver weight in adult group 10

10 days after injection (**p<0.01).

days after injection (**p<0.01).

LQFUHDVHG WKH VLJQLÂżFDQWO\ S SDUDOOHO ZLWK sever histological changes in mice liver in the two groups (Figure 3).

3.3. Histological study of testis in adult The seminiferous tubules are in different spermatogenic stages in control group, and in the mice treat-

(a)

(b)

(c)

(d)

Figure 4: Microscopic images of testis slides, 10 days after injection (H & E, 400Ă&#x2014;) (A) Control group and B, C, and D treated groups respectively with doses: 10, 20, 40 mg/kg CdSe:ZnS. (Sz: spermatozoa, Art: artery vessel, Lc: leydig cells, Lp: lamina propria, Spg: spermatogoni, Spc: spermatocyte, Spt: spermatid).

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Table 1: Average and mean comparison of sperm stem cell numbers in one tubule in adult group after injection (*p < 0.05, **p < 0.01).

*URXSV Q PLFH

Parameter 40 mg/kg

20 mg/kg

10 mg/kg

Control

*18 Âą 6.94*

32 Âą 6.67

33 Âą 8.94

34 Âą 6.39

Mean spermatogonia

29 Âą 10.76**

43 Âą 8.04

45 Âą 8.45

44 Âą 9.35

Mean spermatocyte I

83 Âą 23.44**

109 Âą 20.72

113 Âą 23.29

111 Âą 33.63

Mean spermatid

ed with all three doses of CdSe and CdSe:ZnS QDs, spermatozoids were observed in lumen tubules, but in the group treated with 40 mg/kg CdSe:ZnS QDs, abnormal growth of seminiferous tubes, impaired spermatogenesis, reduction in number of spermatogonia, spermatocyst 1, spermatids and an obvious decrease in matured sperms of lumen were noticed (Table 1). On the other hand, degeneration of the interstitial tissue and blood vessels and reduction in thickness of the lamina propria are illustrated in Figure 4. 3.4. Histological study of liver in adult The results of histological changes in liver tissues

examination in samples of liver in the group treated with 10, 20, 40 mg/kg QDs in dose-dependent manner revealed some abnormal morphology characteristics For acute toxicity study, liver tissues in group treated with 20, 40 mg/kg QDs showed presence of activated kupffer cells, sinusoidal dilatation and cytoplasmic vacuolation and nuclear destruction and nuclear matWHUV VOLJKW LQÂżOWUDWHG LQĂ&#x20AC;DPPDWRU\ FHOO 7KH FKDQJHV in the experimental histopathologic parameters for liver were shown in Figure 5. With the increase in the quantum dots applications LPSRUWDQFH LQ ELRORJ\ DQG PHGLFLQH ÂżHOGV WR[LFLW\ tests of quantum dots have been widely considered

(a)

(b)

(c)

(d)

Figure 5: Microscopic images of liver slides, 10 days after injection (H & E, 400Ă&#x2014;) (A) Control group and B, C and D treated JURXSV ZLWK GRVHV PJ NJ &G6H + +HSDKRF\WH 1 1XFOHXV 6 6LQXVRLG ,F ,QĂ&#x20AC;DPPDWRU\ FHOOV

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[2, 3, and 16] and Cytotoxicity of these particles is an important factor in their use in medicine and then has been considered highly in recent years [17, 18]. This study indicates that there are any previous study LQ WR[LFLW\ RI TXDQWXP ÂżHOGV RQ WKH WHVWLV DQG OLYHU However, the potential effects of nanoparticles on the reproductive system, placenta translocation, and fetus development are still far from even basic evaluations, although some researchers suggested the importance of reproductive toxicity of nanoparticles [2, 19, and 20]. For example, C60 nanoparticles intratracheally administered also induced adverse effects on the mouse male reproductive function [2, 19, and 21]. Also some researchers showed fetal CB exposure sigQLÂżFDQWO\ UHGXFHG '63 LQ PDOH RIIVSULQJ :KHQ &% was administered to adult mice, DSP decreased sigQLÂżFDQWO\ > @ 7KHUHIRUH &% UHGXFHV '63 WKURXJK both fetal exposure and exposure during adulthood. Furthermore, it has been reported that fetal exposure to diesel exhaust (DE) lowers the DSP of male offspring [19, 22]. Diesel exhaust consists of various components, including DEP. The carbon nanoparticles used in the present study are made of carbon, which is the basic structure of DEP. Therefore, fetal DE exposure may lower DSP in male offspring due to particulate matters in DE, particularly CB. However, in the present study, it was not clear whether CB lowered DSP by altering the maternal environment or by directly affecting fetuses. In the future, it will be necessary to determine the effects of CB on both dams and offspring. In the testis of male offspring, intercellular adhesions of seminiferous epithelia and seminiferous tubules damage were observed. The low cellular adhesion of seminiferous epithelia may indicate reduced adhesion of Sertoli and spermatogenic cells. Because Sertoli cells supply nutrients and send signals for cellular differentiation to spermatogenic cells, weak adhesion of Sertoli and spermatogenic cells may inhibit spermatogenesis and thus fetal CB exposure decreases DSP in male pups [21, 22]. However, there is no linear relationship between ages and seminiferous tubule damage or DSP. The progression of sexual maturation might be related to such appearances, but not in a linear relationship. To further investigate these results, we should measure various factors, e.g., the adhesion molecule, testicular gene expression, and intratesticu70

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lar regulators. When adult mice were exposed to CB, the incidence of seminiferous tubule damage was high; however, its severity was mild [7, 22]. In addition, fetal CB exposure leads to weak cellular adhesions in seminiferous tubules; however, CB administration to adult mice induced vacuolation of the seminiferous tubules [21]. As well as research results show treatments with TiO2 DQG *ROG QDQRSDUWLFOHV IRU SUHJQDQW ZRPHQ is one of the previous studies incriminating cytotoxic effects on spermatogensis and histopathology changes of testis in their male children. In vitro studies showed also cyctotoxic effect of TiO2 on living power of mice OH\GLJ FHOOV *ROG QDQRSDUWLFOHV GHFUHDVH PRYHPHQW of matured sperms, silver and aluminum nanoparticles being toxic for stem cells of rat spermatogonia [9]. In this study, the cytotoxicity in vivo of CdSe:ZnS QDs with 2-3 nm size, synthesized by sedimentation method was studied. Histopathology studies of testis tissues did not show toxicity effect of these nanoparticles in the case of mice treated with dose 10 and 20 mg/kg of CdSe:ZnS. According to these studies, the number of spermatogonia, spermatocytes, spermatids, and matured sperms in seminiferous tubes were similar in treated with dose 10 and 20 mg/kg of CdSe:ZnS. groups and control. but in the group treated with 40 mg/kg CdSe:ZnS QDs, abnormal growth of seminiferous tubes, impaired spermatogenesis, reduction in number of spermatogonia, spermatocyst 1, spermatids and an obvious decrease in matured sperms of lumen were noticed Also, the study of body and testis weight showed a weight decreasing in the case of 40 mg/kg dose of CdSe:ZnS QDs. The toxicity effect of &G6H =Q6 TXDQWXP GRW ZDV D YHU\ VLJQLÂżFDQW LQFUHDVH in liver. So that in sections of liver in the group treated with 10, 20, 40 mg/kg QDs in dose-dependent manner revealed some abnormal morphology.

4. CONCLUSIONS In this research cytotoxic effect of CdSe:ZnS QDs on liver and testis tissues of animals and testis , body, liver weight in adult mice indicated that the nanoparticles were passed through the membrane of different cells and even cross blood barrier-testicular and have affected of testis and liver. Although, CdSe:ZnS in vi-

Valipoor A et al

tro condition shows high control of CdSe toxicity because of ZnS coverage in this study and higher in vivo toxicity of CdSe:ZnS even in nucleus and nuclear PDWWHUV ZLWK UHJDUG WR WKH ODFN RI UHYLHZ LQ WKLV Â¿HOG discussed in relation to the Reason for the increase body and testis weight need to further molecular research.

REFERENCES 1. Dabbousi B.O., Rodriguez-Viejo J., Mikulec F.V., Heine J.R., Mattoussi H., et al., Phys. Chem. B, 101 (1997), 9463. 2. Park E.J., Kim H., Kim Y and Park K., Toxicol Environ Health Sci., 25 (2010), 279. 2EHUGRUVWHU * 0D\QDUG $ 'RQDOGVRQ . &DVWUDnova V., Fitzpatrick J. et al., Part. Fibre. Toxicol., 2 (2005), 8. 4. Alivisatos P., Nat Biotechnol., 22 (2004), 47. 5. Aldana J., Wang Y.A., Peng X., Am Chem. Soc., 123 (2001), 8844. 6. Fang B., Chaudhari N.K., Kim M.S., Kim J.H., Yu J.S., Am. Chem. Soc., 131 (2009), 15330. 7. Yu W.W., Chang E., Drezek R., Colvin V.L., Biochem. Biophys. Res. Commun., 348 (2006), 781. +DQ 0 *DR ; 6X - = 1LH 6 Nat Biotechnol., 19 (2001), 631.

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9. Eastman P.S., Ruan W., Doctolero M., Nuttall R., GH)HR * 3DUN - 6 HW DO Nano Lett., 6 (2006), 1059. 10. Smith A.M., Duan H., Mohs A.M., Nie S., Adv. Drug Deliv. Rev., 60 (2008), 1226. 11. Walling M.A., Novak J.A., Shepard J.R., Mol. Sci., 10 (2009), 441. 12. Cano A.D., Sandoval S.J., Vorobiev Y. et al, Nanotechnology, 21 (2010), 4016. 13. Chang S.Q., Dai Y.D., Kang B. et al., Toxicol. Lett., 188 (2009), 104. $PLUL * 5 )DWDKLDQ 6 0DKPRXGL 6 Mater Sci. Appl., 4 (2013), 134. 2EHUGRUVWHU * 2YHUGRUVWHU ( 2EHUGRUVWHU - Environ. Health Perspect., 113 (2005), 823. 16. Yoshida S., Hiyoshi K., Oshio S., Takano H., Takeda K. et al., Fertil. Steril., 93 (2010), 1695. 17. Bae P.K., Kim K.N., Lee S.J., Chang H.J., Lee C.K. et al. Biomaterials., 30 (2009), 836. $KDPHG 0 3RVJDL 5 *RUH\ 7 - HW DO Toxicol Appl Pharmacol., 242 (2010), 263. 19. Roh J.Y., Sim S.J., Yi J., Park K., Chung KH. et al. Environ. Sci. Technol., 43 (2009), 3933. 20. Yoshida S., Hiyoshi K., Ichinose T., Takano H., Oshio S. et al. Androl., 32 (2009), 337. 21. Watanabe N., Toxicol. Lett., 155 (2005), 51. *XR : /L - - :DQJ < $ 3HQJ ; Chem. Mater., 15 (2003), 3125.

AUTHOR (S) BIOSKETCHES Akram Valipoor, Assistant Professor, Physiology Department, Basic Sciences Faculty, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran Email: Valipoor.akram@gmail.com Gholamreza Amiri, Associate Professor, Department of Physic, Falavarjan Branch, Islamic Azad University, Isfahan, Iran Jafar Taheri, Instructor, Department of Chemistry, Islamic Azad University, Shahrekord, Iran Mehdi Abasi, Instructor, Department of Statistics, Islamic Azad University, Shahrekord, Iran Amin Mirzakhani, Instructor, Department of Mechanical Engineering, Payame Noor University, PO BOX 19395-3697 Tehran, Iran

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 87-92

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials $Q (IÂ¿FLHQW *UHHQ 6\QWKHVLV RI &RSSHU 2[LGH 1DQR&U\VWDOOLQH Mahboubeh Kargar* 0DMLG *KDVKDQJ 0RKDPPDG 5H]D 0RKDPPDG 6KDÂ¿HH Faculty of Sciences, Najafabad Branch, Islamic Azad University, Najafabad, Esfahan, Iran

Received: 25 February 2015; Accepted: 28 April 2015

ABSTRACT In this study, a feasible green method for the synthesis of copper oxide nanocrystalline is described by using sour FKHUU\ MXLFH ZKLFK KDV D VLJQLÂ¿FDQW HIIHFW RQ FU\VWDOOLQH VL]H DQG PRUSKRORJ\ 7KH EHQHÂ¿WV RI WKH JUHHQ PHWKRG not only nanometer scale are formed but also low-cost method are obtained in a normal atmosphere which it has EHHQ XVHG &+3COO)2&X +22 LQGLYLGXDOO\ DV &X VRXUFHV $OO VDPSOHV KDYH FDOFLQDWLRQ LQ Â&#x192;& 7KH HIIHFW RI VRXU FKHUU\ MXLFH FRQFHQWUDWLRQ WR FRQWURO FU\VWDO JURZWK LV LQYHVWLJDWHG E\ FKDQJLQJ WKH DPRXQW RI LW WR DQG mL, respectively. The synthesized particles are characterized by using X-ray Diffraction (XRD) and Field Emission 6FDQQLQJ (OHFWURQ 0LFURVFRS\ )( 6(0 3RZGHU ; UD\ 'LIIUDFWLRQ DQDO\VLV FRQÂ¿UPV WKDW SXUH &RSSHU 2[LGH nanocrystallines are in a single phase monoclinic structure which the average crystalline size has estimated via :LOOLDPVRQ +DOO SORW IURP WKH KLJKHVW SHDN RI WKH ;5' ZDV DPRQJ QP IRU DOO VDPSOHV Keywords: &X2 QDQRFU\VWDOOLQH *UHHQ V\QWKHVLV 6RXU &KHUU\ MXLFH :LOOLDPVRQ +DOO SORW &RSSHU R[LGH

1. INTRODUCTION ,Q WKH UHFHQW \HDUV QDQRPDWHULDOV KDYH D VLJQLÂ¿FDQW role in various practical applications with their unique morphology such as spherical nanoparticles, nanorods, nanoribbons, nanobelts and nanoplatelets [1-3]. On the one hand, nanostructured transition metal oxides (MO), of a special class nanomaterials, are prerequisite for the improvement of different novel functional and smart materials. These transition metal oxides nanocrystals have been attracting much concentration for fundaPHQWDO VFLHQWLÂ¿F UHVHDUFK WKDQNV WR WKHLU H[FHSWLRQDO (*) Corresponding Author - e-mail: mahboubeh_kargar @yahoo.com

physical and chemical properties. These properties are strongly associated with the size of crystalline, shapes, composition, and structures of nanocrystals [4]. CuO nanoparticles are of considerable technological interest in various applications, such as solar cell, batteries, catalytic, and superconductors because of its unique properties [5]. On the other hand, Various methods are available to prepare CuO nanoparticles, including microwave irradiation [6], solâ&#x20AC;&#x201C;gel [7], solid-state reaction [8], precipitation-pyrolysis [9], and thermal decompo-

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sition [10] methods. First of all, Some of these methods are costly and require extensive instruments. Furthermore, the addition of chemical agents causes to a large quantities of wastes inserted into water sources and environments [1-10]. Obviously, some noxious effect has been seen in the medical application because chemical synthesis methods lead to the presence of any toxic chemical absorbed on the surface. The most challenging subjects to chemist is obtaining high-quality nanomaterials, which achieve appropriate substance regard to chemical purity, phase selectivity, crystallinity and homogeneity in particle size with controlled state of agglomeration infeasible and low-cost process [11]. To solve these problems a simple and green chemical method that is biosynthesis has attracted attention using fungi, actinomycetes, fruit, and plant extracts. These methods usually are green, low cost, solventfree, non-toxic and environmentally benign precursors for the synthesis of nanostructures. Recently, the biosynthesis of copper oxide nanoparticles have been excessive interesting and some green methods have been advanced, including the use of 3K\OODQWKXV $PDUXV /HDI H[WUDFW > @ *ORULRVD VXperb-L extract [5], D-glucose [12], Centella asiatica plants [13], and Urea [14], gum karaya [15] which will have been investigated. Sour Cherry juice is renowned for its bioactivities such as inhibition of tumor development, protection against a broad range of human diseases and prevention of some cardiovascular risk factors [16-18]. The anthocyanins existed in Sour cherry reduced the seYHULW\ RI LQĂ&#x20AC;DPPDWRU\ V\PSWRPV VXFK DV HGHPD JRXW and arthritis. Sour Cherry is rich in bioactive comSRXQGV LQFOXGLQJ K\GUR[\FLQQDPDWHV Ă&#x20AC;DYRQRLGV and procyanidins. The existence of phenolic compounds in Sour Cherry juice make it a good candidate for the synthesis of nanomaterials due to the ability of phenolic compounds to act as chelating agents [1618]. ,Q WKH FXUUHQW HVVD\ DQ DWWHPSW LV WR ÂżQG WKH HIÂżciency of Sour Cherry juice as a stabilizer and capping agent in the synthesis of CuO nanocrystalline, juice with varying concentration have been used for the study. The effect of sour cherry juice concentration to control crystal growth was investigated. 88

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2. EXPERIMENTAL 2.1. Physical measurements 3KDVH LGHQWLÂżFDWLRQ ZDV FDUULHG RXW IRU WKH DV SUHFLSLtated and heat treated samples by an X-ray Diffraction (XRD) method with a Rigaku D-max C III, X-ray difIUDFWRPHWHU XVLQJ 1L ÂżOWHUHG &X .ÄŽ UDGLDWLRQ )LHOG Emission Scanning Electron Microscope (FE-SEM) images were obtained on HITACHI S-4160. 2.2. Synthesis of CuO particles Cu(OAc)2 was purchased from Merck Company (AlGULFK DQG XVHG ZLWKRXW IXUWKHU SXULÂżFDWLRQ &X2 nanostructures were prepared by the following experimental sequence: A solution of Sour Cherry juice combined with 20 mL aqueous ammonia was added drop wise into a solution containing (CH3COO)2Cu (30 mmol) and 40 mL of Sour cherry juice in 200 mL of water under magnetic stirring. The obtained mixture was stirred at room temperature for 30 min. The resultant dark blue SUHFLSLWDWHV ZHUH ÂżOWHUHG ZDVKHG ZLWK GLVWLOOHG ZDWHU and absolute ethanol and dried at room temperature. Moreover, the experiment was carried out by using 20, 40 and 80 mL of Sour Cherry at the same conditions, respectively. The precipitates were then heated slowly XS WR Â&#x192;& LQ DQ HOHFWULF IXUQDFH XVLQJ DOXPLQD FUXcibles and maintained at the stable mentioned temperature for 3h. After calcination, the obtained products of black CuO were stored in airtight container for further analysis.

3. RESULTS AND DISCUSSIONS The correct crystallinity corresponding to those of single phase monoclinic structure (space group C2/c), ZLWK ODWWLFH SDUDPHWHUV D c E c DQG F c Č&#x2022; Â&#x192; -&3'6 ZDV observed in the XRD pattern of powders that is represented in Figure 1. Based on the powder diffraction peak broadening, the strain value (H) of CuO nanoparticles was evaluated by using the slope of the Williamson-Hall plot on Table. 1 [19]. Clearly, the crystals have grown completely and have decreased their size and crystalline by increasing the

Kargar M et al

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 87-92

Table 1: Determine the size of the crystal, strain value of CuO nanoparticles.

Amount of sour cherry juice 20cc 40cc

Strain value (H) 0.0038 0.0009

Crystallity size by Williamson-Hall (nm) 55 15

80cc

0.0009

15 amount of Sour Cherry juice. In this essay, the Sour Cherry juice was used as an effective controlling agent of size and morphology. The presence of this surfactant produces the particulate centers for nucleation and outgrowth of discrete particles. Anthocyanins are the major component present in Sour Cherry and most likely are responsible for uniform shapes and sizes of the ensuing nanoparticles [20]. Schematic diagram illustrates the effect of antioxidants from Sour Cherry fruit on Figure 2. In order to have further investigation, the effect of concentration of the Sour Cherry juice was studied by changing the amount of Sour Cherry juice from 20 to 40 and 80 mL and changing on the morphology of the samples was investigated by FE-SEM technique (Figure 3). From Figure 3, it was revealed that as synthesized CuO samples undergoes a high degree of agglomeration and taken a mud pottery like shape. Only a small difference is observed between nano-particles

Figure 1: XRD patterns of CuO particles synthesized using (a) 20 mL; (b) 40 mL (c) 80 mL of Sour Cherry juice.

R1 O+ +O

R1 N+4O+

O O

O+ O+ O

O O R1

Cu2+

O O

R2 O

O O Cu2+

O O

R1 O

O R2

Figure 2: Schematic of effect of antioxidants from sour cherry juice in synthesis of CuO nanocrystalline.

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Figure 3: FE-SEM photographs of CuO nanoparticles synthesized using 20 mL (a,b), 40 mL (c,d) and 80 mL (e,f) of sour cherr juice.

shape measured by FE-SEM. The agglomeration process took place between the CuO nanoparticles capped by anthocyanin molecules in the juice due to the presence of hydrogen bonding [21]. In order to have a comparison between the size of

the as-prepared samples and to understand the effect of the sour cherry juice concentration on the particle size an statistical analysis was performed from the FESEM images to obtain information about the particle size distribution of the samples and the results are

Figure 4: Diagram of CuO particles size synthesized using (a) 20 mL, (b) 40 mL, and (c) and 80 mL of sour cherry juice.

Kargar M et al

shown in Figure 4. It was revealed that the diameters of the sample are in the range of 20-200 nm. Changes on the sour cherry juice concentration did not change the shape of the CuO nanoparticles, but it caused a decrease in the particle size with increasing on the juice concentration. The average particle size of the samples are 105, 90 and 70 nm for the juice concentrations of 20, 40 and 80 mL respectively. In comparison XRD results, the particle size has decreased with the enhancing of sour cherry juice which led to lower strain value. In spite of agglomerated particle, crystal size has decreased, which can be used in various applications.

4. CONCLUSIONS In a nutshell, CuO nanocrystalline with various morphologies have been successfully prepared via a coprecipitation method with copper acetate and sour cherry juice as surfactant is the originality of this ZRUN ZKLFK WKH NLQG RI VXUIDFWDQW KDV D VLJQLÂżFDQW effect on the crystalline size, morphology products. The advantages of the method, nanometer scale were formed by feasible and low-cost in a normal atmosphere if green synthesis. The XRD results showed that pure CuO powders were formed with the aid of this method without any impurity. It is anticipated that CuO nanoparticles have high potential applications in GLIIHUHQW ÂżHOGV VXFK DV ELRDFWLYLW\ DQG PHGLFLQDO DSplications along with optical/electrical devices.

REFERENCES 1. Nath S.K., Kalita P.K., J. Nanosci. Nanotechnol.: An Int. J., 2 (2012), 8. 6DPEDQGDP $ /HH * - :X - Ultrason. Sonochem., 19 (2012), 682. 3. Zhou K., Wang R., Xu B., Li Y., Nanotechnology, 17 (2006), 3939. =KDQJ 4 =KDQJ . ;X ' <DQJ * +XDQJ + Nie F., Liu Ch., Yang Sh., Mate. Sci., 60 (2014), 208. 5. Raja Naika H., Lingaraju K., Manjunath K., KuPDU ' 1DJDUDMX * 6XUHVK ' 1DJDEKXVKDQD

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H., J. Taibah Univ. Sci., 9 (2015), 7. 6. Wang H., Xu J.Z., Zhu J.J., Chen H.Y., J. Cryst. Growth, 244 (2002), 88. =KDQJ 4 /L < ;X ' *X = J. Mater. Sci. Lett., 20 (2001), 925. 8. Xu J.F., Ji W., Shen Z.X., Tang S.H., Ye X.R., Jia D.Z., Xin X.Q., J. Solid State Chem., 147 (2000), 516. 9. Yia A.J., Li J., Jian W., Bennett J., Xu J.H., Appl. Phys. Lett., 79 (2001), 1039. 10. Fan H., Yang L., Hua W., Wu X., Wu Z., Xie S., Zou B., Nanotechnology, 15 (2004), 37. 11. Acharyulu N.P.S., Dubey R.S., Swaminadham V., Kalyani R.L., Kollu P., Pammi S.V.N., Int. J. Eng. Res. Technol., 3 (2014), 639. 12. M. Ahamed, P. Karuppiah, H. A. Alhadlaq, N. A. Al-Dhabi, M. A. Majeed Khan, J. Nanomater., 2014 (2014), 4. 13. Yang R.C., Zhang Z.H., Ren Y.M., Zhang X., Chen Z.M., Xu M.D., J. Materi. Sci. Technol., 31 (2014), 25. 14. Tadjarodi A., Roshani R., J. Curr. Chem. Lett., 3 (2014), 215. 15. Vellora V., Padil Th., CernĂk M., Int. J. Nanomedicine, 8 (2013), 889. 16. Bonerz D., Wurth K., Dietrich H., Will F., Eur. Food Res. Technol., 224 (2007), 355. 17. Capanoglu E., Boyacioglu D., de Vos R.C.H., Hall R.D., Wilder B., J. Berry Res., 1 (2011), 137. 18. M. Toht-Marcus, F. Boross, P. Molnar, 1993. Int. Federation of Fruit Juice Producers (IFU) Symposium (Budapest), 329. 19. Khorsand Zak A., Abd. Majid W.H., Abrishami 0 ( <RXVHÂż 5 J. Solid State Sci., 13 (2011), 251. 20. Kaume L., Howard L.R., Devareddy L., J. Agric. Food Chem., 60 (2012), 5716. 7DYDNROL ) 6DODYDWL 1LDVDUL 0 *KDQEDUL ' 6Dberyan K., Mostafa Hosseinpour-Mashkani S., J. Mater. Res. Bull., 49 (2014), 14.

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AUTHOR (S) BIOSKETCHES Mahboubeh Kargar, Instructor, Faculty of Sciences, Najafabad Branch, Islamic Azad University, Najafabad, Esfahan, Iran Email: mahboubeh_kargar @yahoo.com Majid Ghashang, Assistant Professor, Faculty of Sciences, Najafabad Branch, Islamic Azad University, Najafabad, Esfahan, Iran 0RKDPPDG 5H]D 0RKDPPDG 6KDÂżHH, Assistant Professor, Faculty of Sciences, Najafabad Branch, Islamic Azad University, Najafabad, Esfahan, Iran

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 93-100

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Electronic Structure Investigation of Octahedral Complex and Nano ring by NBO Analysis: An EPR Study Mehrnoosh Khaleghian1*, Fatemeh Azarakhshi2, Gholamreza Ghashami3 1

Department of Chemistry, Islamshahr Branch, Islamic Azad University, Tehran, Iran

Department of Chemistry, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran 3

Department of Engineering, Islamshahr Branch, Islamic Azad University, Tehran, Iran

Received: 8 March 2015; Accepted: 11 May 2015

ABSTRACT To calculation non-bonded interaction of the [CoCl ]3- complex embedded in nano ring, we focus on the single wall boron-nitride B N QDQR ULQJ 7KXV WKH JHRPHWU\ RI % 1 QDQR ULQJ KDV EHHQ RSWLPL]HG E\ % /<3 PHWKRG ZLWK EPR-II (Electron paramagnetic resonance) basis set and geometry of the [CoCl ]3- complex has been optimized at % /<3 PHWKRG ZLWK $OGULFKÂ¶V 97= EDVLV VHW DQG 6WXWWJDUW 56& (IIHFWLYH &RUH 3RWHQWLDO $OVR 1%2 1DWXUDO %RQG 2UELWDO DQDO\VLV VXFK DV /802 ORZHVW XQRFFXSLHG PROHFXODU RUELWDO DQG WKH +202 KLJKHVW RFFXSLHG molecular orbital) for the lowest energy have been derived to estimate the structural stability and band gaps, Natural atomic orbitals, Fermi energy, absorption energy of the B N -[CoCl ]3- nano system can be distinguished based on these NBO data. Total atomic charges, Total atomic spin densities, Isotropic Fermi Contact Coupling and JHRPHWULFDO TXDQWLWLHV RI GLIIHUHQW ORRSV RI % 1 QDQR ULQJ LQFOXVLYH >&R&O ]3- embedded in the nano ring at the OHYHO RI % /<3 WKHRU\ DQG (35 ,, EDVLV VHW IRU % 1 &O DWRPV DQG $OGULFKÂ¶V 97= EDVLV VHW DQG 6WXWWJDUW 56& Effective Core Potential for Co (III) have been calculated by Gaussian quantum chemistry package. Keywords: 'HQVLW\ IXQFWLRQDO WKHRU\ (35 ,, +202 /802 1XFOHDU LQGHSHQGHQW FKHPLFDO VKLIW 1%2

1. INTRODUCTION To introduce physical properties of B24C12N24 molecule [1] and the B12N12, B16N16 and B28N28 molecules, the experimental synthesis and various spectrometers are QHHGHG IRU WKHLU VWUXFWXUDO VWDELOLWLHV FRQÂ¿UPDWLRQ > 4]. The schematic of B18N18 is displayed in the Figure 1. In present work we presentation the non-bonded interaction of the [CoCl6]3- embedded in B18N18 nano ring. The basically purpose of this investigation was the study of the electromagnetic interactions within the

(*) Corresponding Author - e-mail: mehr_khaleghian@yahoo.com

B18N18-[CoCl6]3- nano system. In chemistry, octahedral geometry describes the shape of compounds where six atoms or groups of atoms or ligands are symmetrically DUUDQJHG DURXQG D FHQWUDO DWRP GHÂ¿QLQJ WKH YHUWLFHV of an octahedron compound. For further evaluation about electromagnetic interactions, stability structure of [CoCl6]3- complex under the different loops of nano ring have been determined. For further structural information, the lowest unoccupied molecular orbital and

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 2 (2015), 93-100

the highest occupied molecular orbital differences, namely band gaps and the hybrids on atom have been reported to explore the ability of the [CoCl6]3- to create a stable B18N18-[CoCl6]3- nano system.

2. COMPUTATIONAL DETAILS To determination electromagnetic interactions of the [CoCl6]3- complex including octahedral symmetric &R ,,, FRRUGLQDWLRQ FRPSRXQGV DQG VL[ Ê&#x152; DFFHSWRU ligands, the geometry of the [CoCl6]3- have been optimized at B3LYP method with Aldrichâ&#x20AC;&#x2122;s VTZ basis set and Stuttgart RSC 1997 Effective Core Potential. The geometry of the B18N18 nano ring and [CoCl6]3complexes have been optimized at B3LYP method with EPR-II (Electron paramagnetic resonance) ba-

Khaleghian M et al

VLV VHW XVLQJ DE LQLWLR *$866,$1 TXDQWXP FKHPLFDO package. Vibrational frequencies have been calculated at B3LYP method with EPR-II basis set to analyze the thermochemical functions including enthalpies DQG *LEEV IUHH HQHUJLHV > @ 7KH QDWXUDO ERQG RUELWDO (NBO) analysis [6, 7] has also been applied to study the intermolecular orbital interactions in the complexHV > @ $OVR 1%2 GDWD DQG Ç»( LQ >&R&O6]3- complex in different loops of the B18N18 nano ring have been calculated.

3. RESULTS AND DISCUSSION The geometry of the [CoCl6]3- complex including octahedral symmetric Co (III) coordination compounds DQG VL[ Ê&#x152; GRQRU OLJDQGV KDYH EHHQ RSWLPL]HG DW % /-

Table 1: Optimized parameters of octahedral symmetric Co (III) coordination comSRXQGV DQG VL[ Ê&#x152; GRQRU OLJDQGV

[CoCl6]3-

Compound

Bond ID

Bond lengths

Bond angles

Co(1)- Cl (2) Co(1)- Cl (3) Co(1)- Cl (4) Co(1)- Cl (5)

2.048 1.924 2.049 2.049

Co(1)- Cl (6)

1.924

Co(1)- Cl (7)

2.048

Cl (2)-Co(1)- Cl (3)

90.000

Cl (2)-Co(1)- Cl (4)

90.001

Cl (2)-Co(1)- Cl (5) Cl (2)-Co(1)- Cl (6)

89.999 90.000

Cl (2)-Co(1)- Cl (7)

179.998

Cl (3)-Co(1)- Cl (4)

90.002

Cl (3)-Co(1)- Cl (5)

89.998

Cl (3)-Co(1)- Cl (6)

179.997

Cl (3)-Co(1)- Cl (7)

90.000

Cl (4)-Co(1)- Cl (5) Cl (4)-Co(1)- Cl (6) Cl (4)-Co(1)- Cl (7)

180.000 90.002 90.001

Cl (5)-Co(1)- Cl (6) Cl (5)-Co(1)- Cl (7) Cl (6)-Co(1)- Cl (7)

89.998 89.999 90.000

See Figure 1 for more details.

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Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 2 (2015), 93-100

Table 2: Natural atomic orbitals of [CoCl6]3- complex with six ʌ GRQRU OLJDQGV

Natural atomic orbital [CoCl 6]3Atom

Co3+ (1)

Cl (2)

Cl (3)

Cl (4)

Cl (5)

Cl (6)

Cl (7)

Atomic Orbital 4s 3dz2 3dxy 3dyz 3dx2y2

Energy 1.62632 0.38196 0.35387 0.35351 0.32882

Occ. 0.20611 1.2198 1.09592 1.08186 1.27044

3dxz

0.23313

1.99444

-1.29779

1.98981

2px

0.3623

1.99933

2py

0.3626

1.97802

2 pz

0.33289

1.89911

-1.3661

1.98486

2px

0.30109

1.89182

2py

0.3403

1.96424

2 pz

0.33939

1.99917

2s 2px 2py

-1.32367 0.3385 0.30771

1.98987 1.98557 1.87786

2 pz

0.33891

1.98182

-1.32277

1.98986

2px 2py 2 pz 2s

0.33934 0.3085 0.33975 -1.36678

1.98561 1.87798 1.98184 1.98487

2px

0.30051

1.89217

2py

0.33971

1.96467

2 pz 2s 2px 2py 2 pz

0.33886 -1.29779 0.3623 0.3626 0.33289

1.99918 1.98981 1.99933 1.97802 1.89911

YP method with Aldrich’s VTZ basis set and Stuttgart RSC 1997 Effective Core Potential. Optimized parameters of [CoCl6]3- such as bond lengths and bond angles have been reported in Table 1. We can view the Co-Cl (3) and Co-Cl (6) bond lengths are less than other bond lengths, because the octahedral symmet-

ULF &R ,,, FRRUGLQDWLRQ FRPSRXQGV DQG VL[ ʌ GRQRU ligands are High-spin d6 HOHFWURQLF FRQ¿JXUDWLRQ 6 2) exhibit the Elongation Jahn–Teller distortion [9]. In accordance with the occupancy values of metal Co (III) in Table 2, it was elaborated that 3dxz orbital consists of two electrons and has the least value of 95

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 2 (2015), 93-100

energy. The other d orbitals are single and 4S orbital has no electron. Also, in accordance with the occupancy and energy YDOXHV IRU OLJDQGV RI Ę&#x152; GRQRU LQ DWRPV &O &O it was demonstrated that three non bonding electron pairs of Cl are in 2s and two 2p orbitals that have higher energy levels. For instance, in Cl (2), 2pz is single and has a lower energy level; 2px and 2py that have higher energy levels and are nearer to the metal d orELWDOV LQ HQHUJ\ LQWHUIHUH WR PDNH PROHFXODU Ę&#x152; RUELWDOV DQG V RUELWDOV LQWHUIHUH WR PDNH WKH Äą PROHFXODU RUELWals. In addition, related to Table 2 data, atoms Cl (4) â&#x20AC;&#x201C; Cl (5), Cl (3) â&#x20AC;&#x201C; Cl (6) and Cl (2) â&#x20AC;&#x201C; Cl (7) that are in one direction related to Co (III), are the same in occupancy and energy levels (Figure 1-a). For further to determination non-bonded interaction of the [CoCl6]3- complex embedded in nano ring, we focus on the single

(a)

(b)

Figure 1: The optimized geometrical structure of the a) [CoCl6]3- complex and b) B18N18-[CoCl6]3- nano system at the level of B3LYP/EPR-III theory.

Khaleghian M et al

wall boron-nitride an armchair B18N18 nanotube with FKLUDOLW\ Q P DQG WKH VFKHPDWLF RI RSWLPL]HG structure of the B18N18-[CoCl6]3- system have been displayed in Figure 1. DFT (Density functional theory) calculations, as well as hybrid methods (B3LYP) for B18N18-[CoCl6]3nano system have been carried out to study the nonbonded interaction. The geometry of B18N18 nano ring has been optimized by B3LYP method with EPR-II basis set. The electromagnetic interactions of the [CoCl6]3- complex embedded in nano ring have been investigated at B3LYP in different loops of the B18N18 nano ring. According to the frequency calculation at the level of B3LYP/EPR-II theory, obtainLQJ WKHUPR FKHPLFDO IXQFWLRQV VXFK DV Çť* NFDO PRO DQG Çť+ NFDO PRO FRQÂżUPHG WKH structural stability of B18N18 nano ring. The geometry of B18N18 nano ring and [CoCl6]3- have been optimized by B3LYP method with EPR-II basis set for B, N, Cl atoms and Aldrichâ&#x20AC;&#x2122;s VTZ basis set and Stuttgart RSC 1997 ECP (Effective core potential) for Co (III). So it is notable that the obtained energy of mentioned basis set and ECP for B18N18 nano ring and [CoCl6]3- were -1434.1167014 and -744.7157743, (Hartree) respectively. To investigate the non-bonded interaction on [CoCl6]3- with six different loops of B18N18 nano ring, ÂżUVW WKH ÂżYH KH[DJRQ ORRSV KDYH EHHQ IUHH]HG DQG WKH electrostatic interaction of [CoCl6]3- with the one remained active loop have been considered. Other loops have been examined one by one in the same way and the changes of all the following calculated quantities have been explored. In accordance with Figure (1b), it is demonstrated that atoms Cl (42) and Cl (39) are exactly in central direction of loop 3, loop 6. For further structural information, the lowest unoccupied molecular orbital and the highest occupied molecular orbital differences, namely band gaps have been reported to explore the ability of the suitable [CoCl6]3forms to create a stable B18N18-[CoCl6]3- system. So, TXDQWLWLHV YDOXHV VXFK DV WKH UHODWLYH HQHUJLHV Çť( radial coordinate of dipole moment (r), band gaps, Dipole orientation and NICS (Nuclear independent chemical shift) of B18N18-[CoCl6]3- system have been reported in Table 3. Natural bond orbital (NBO) analysis of the [CoCl6]3complex embedded in nano ring, such as ionization

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Table 3: 5HODWLYH HQHUJLHV Çť( UDGLDO FRRUGLQDWH RI GLSROH PRPHQW U DQG EDQG JDS RI >&R&O6]3- under different loops of B18N18 at EPR-II basis set for B,N,F atoms and Def2-TZVP basis set and Stuttgart RSC 1997 Effective Core Potential for Co (III).

Basis sets for Co3+ Def2-TZVP , Stuttgart RSC 1997 ECP

Compound band gap (a.u.)

Çť( (Hartree)

NICS

Dipole moment (Debye)

[CoCl6]3-

0.18716

-744.7157

0.0085

Dipole orientation Č&#x2122; Äł 90 0

B18N18

0.16409

-1434.1167

0.0000

loop 1-[CoCl6]3-

0.00563

-983.4365

-9.8094

14.999

58.864

loop 2-[CoCl6]3-

0.04882

-983.5047

-9.8196

8.5251

136.0460

loop 3-[CoCl6]3-

0.05779

-983.4791

-9.8051

8.1247

165.6071

loop 4-[CoCl6]3-

0.03409

-983.4757

-9.8094

7.9953

113.1564

loop 5-[CoCl6]3-

0.04873

-983.5047

-9.8196

8.5441

44.02423

0.15495

-983.4417

-9.8051

15.7468

0.540243

B18N18-[CoCl6]

loop 6-[CoCl6]

energy(IE);that the ionization energy (IE) of an atom or molecule refers to the energy required to remove a single electron from a single atom or molecule, electron DIÂżQLW\ HQHUJ\ (ea WKDW WKH HOHFWURQ DIÂżQLW\ RI DQ DWRP RU PROHFXOH LV GHÂżQHG DV WKH DPRXQW RI HQHUJ\ released when an electron is added to a neutral atom or molecule in the gaseous state to form a negative ion, energy gap or band gap (Eg); that the band gap generally refers to the energy difference (in electron volts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors

have been reported in Table 4. This is equivalent to the energy required to free an outer shell electron from its orbit about the nucleus to become a mobile charge carrier, able to move freely within the solid material, so the band gap is a major factor determining the electrical conductivity of a solid. Substances with large band gaps are generally insulators, those with smaller band gaps are semiconductors, while conductors either have very small band gaps or none, because the valence and conduction bands overlap and Fermi energy (Ef); that the Fermi energy also called electrochemical poten-

Table 4: Natural bond orbital (NBO) analysis of the [CoCl6]3- complex embedded in B18N18 nano ring.

Basis sets for Co3+ Compound

Aldrichâ&#x20AC;&#x2122;s VTZ, Stuttgart RSC 1997 ECP IE Eea Eg HOMO(ev) (ev) (ev) (ev) 5.64 -5.64 -10.73 5.09

[CoCl6]3-

LUMO (ev) 10.73

B18N18 1,2,4,34,35,36 3,5,6,7,8,9

-3.4 5.46 5.84

-7.86 5.31 4.52

7.86 -5.31 -4.52

3.4 -5.46 -5.84

4.46 0.15 1.32

-5.63 5.385 5.18

10,11,12,13,14,16 15,17,18,19,20,21 22,23,24,25,26,28 27,29,30,31,32,33

5.86 5.46 5.85 7.71

4.29 4.53 4.52 3.49

-4.29 -4.53 -4.52 -3.49

-5.86 -5.46 -5.85 -7.71

1.57 0.93 1.33 4.22

5.075 4.995 5.185 5.6

EF (ev) 8.185

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Table 5: Different quantities of [CoCl6]3- under six different loops of B18N18 nano system at the level of B3LYP theory and EPR-II basis set for B, N, Cl atoms and Aldrich’s VTZ basis set and Stuttgart RSC 1997 Effective Core Potential for Co (III). Different quantities of [CoCl6]3- under different loops of B18N18 nano ring Total atomic charges Total atomic spin densities Isotropic Fermi Contact Coupling (10(-4) cm-1) loop 1-[CoCl6]3B (1) -0.056 0.109 13.132

B (2) -0.056 0.109 13.132

N (4) -0.279 0.222 4.059

N (34) -0.106 0.025 7.976

B (35) -0.173 0.658 48.937

N (36) -0.106 0.025 7.976

Co (37) 1.504 2.548 -0.035

Cl (38) -0.738 0.112 16.769

Cl (39) -0.538 -0.043 10.678

Cl (40) -0.672 -0.030 7.966

Cl (41) -0.467 0.204 16.731

Cl (42) -0.568 -0.053 8.412

Cl (43) -0.738 0.112 16.769

B (3) -0.048 0.158 8.748

B (5) -0.063 -0.013 1.802

N (6) -0.013 0.027 2.404

N (7) -0.063 -0.013 1.802

B (8) -0.206 -0.005 -0.271

Loop 2-[CoCl6]3N (9) Co (37) Cl (38) -0.013 1.604 -0.741 0.027 3.256 0.150 2.404 -0.043 17.886

Cl (39) -0.704 0.085 18.356

Cl (40) -0.750 0.104 18.634

Cl (41) -0.579 -0.022 21.070

Cl (42) -0.677 0.092 17.922

Cl (43) -0.741 0.150 17.886

Loop 3-[CoCl6]3B (10) -0.094 0.010 -1.325

B (11) -0.039 -0.146 -7.745

N (12) -0.009 -0.018 -2.249

N (13) -0.094 0.010 -1.325

B (14) -0.009 -0.018 -2.249

N (16) Co (37) Cl (38) -0.215 1.592 -0.741 0.000 3.332 0.151 -0.037 -0.044 16.980 Loop 4-[CoCl6]3-

Cl (39) -0.675 0.150 21.832

Cl (40) -0.761 0.129 17.440

Cl (41) -0.763 0.130 18.511

Cl (42) -0.446 0.118 22.132

Cl (43) -0.741 0.151 16.980

B (15) -0.028 0.264 23.712

B (17) -0.066 -0.024 2.795

N (18) -0.020 0.066 4.713

N (19) -0.066 -0.024 2.795

B (20) -0.211 -0.132 1.599

N (21) -0.020 0.066 4.713

Cl (39) -0.690 0.114 20.625

Cl (40) -0.541 -0.054 7.814

Cl (41) -0.724 0.124 18.297

Cl (42) -0.681 0.113 21.969

Cl (43) -0.778 0.102 18.263

Co (37) 1.609 3.280 -0.044

Cl (38) -0.778 0.102 18.263

Loop 5-[CoCl6]3B (22) -0.063 -0.013 1.815

B (23) -0.048 0.159 8.840

N (24) -0.013 0.028 2.427

N (25) -0.063 -0.013 1.815

B (26) -0.013 0.028 2.427

N (28) Co (37) Cl (38) -0.206 1.604 -0.741 -0.005 3.256 0.150 -0.268 -0.043 17.889 Loop 6-[CoCl6]3-

Cl (39) -0.676 0.092 17.894

Cl (40) -0.579 -0.022 21.096

Cl (41) -0.750 0.104 18.627

Cl (42) -0.704 0.085 18.322

Cl (43) -0.741 0.150 17.889

B (27) -0.196 -0.733 -51.399

B (29) -0.107 0.171 -7.266

N (30) -0.056 -0.109 -14.155

N (31) -0.107 0.172 -7.211

B (32) -0.319 -0.023 -2.241

N (33) -0.057 -0.109 -14.169

Cl (39) -0.379 0.241 14.478

Cl (40) -0.669 0.223 20.201

Cl (41) -0.616 0.285 22.041

Cl (42) -0.615 0.212 21.492

Cl (43) -0.712 0.181 15.997

tial is a total energy level including kinetic energy and potential energy have been considered to justify the structural stability and semi-conducting properties of B18N18-[CoCl6]3- nano systems. In accordance data of Eg in Table 4, [CoCl6]3- - loop 4 nano system is more conductor than other nano system and [CoCl6]3- alone is insulators. Also, total atomic charges; that provide a means of estimating partial atomic charges from calculations carried out by the methods of computational chemistry, spin densities; that Spin density is electron density applied to 98

Co (37) 1.550 3.306 -0.044

Cl (38) -0.712 0.180 15.995

IUHH UDGLFDOV ,W LV GH¿QHG DV WKH WRWDO HOHFWURQ GHQsity of electrons of one spin minus the total electron density of the electrons of the other spin. One of the ways to measure it experimentally is by electron spin resonance and isotropic Fermi contact coupling; that the Fermi contact interaction is the magnetic interaction between an electron and an atomic nucleus when the electron is inside that nucleus. So mentioned parameters of [CoCl6]3- under different loops of B18N18 system at the level of B3LYP theory and EPR-II basis set for B, N, Cl atoms and Aldrich’s VTZ basis set

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Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 2 (2015), 93-100

Table 6: Geometrical quantities of different loops of B18N18 nano ring inclusive embedded [CoCl6]3- in the nano ring at the level of B3LYP theory and EPR-II basis set for B, N, Cl atoms and Aldrich’s VTZ basis set and Stuttgart RSC 1997 Effective Core Potential for Co (III).

Compound B18N18-[CoCl6]3-

loop 1

loop 2

Loop 3

loop 4

loop 5

loop 6

B(1) B(2) N(4) N(34) B(35) N(36) B(3) N(5) B(6) N(7) N(8) B(9) N(10) B(11) B(12) N(13) B(14) N(16) B(15) N(17) B(18) N(19) N(20) B(21) N(22) B(23) B(24) N(25) B(26) N(28) B(27) N(29) B(30) N(31) N(32) B(33)

Bond ID r 1-4 r 4-2 r 2-34 r 1-36 r 35-36 r 34-35 r 3-5 r 3-7 r 5-9 r 6-7 r 8-9 r 6-8 r 11-13 r 11-10 r 12-13 r 10-14 r 12-16 r 14-16 r 15-17 r 15-19 r 17-21 r 18-19 r 18-20 r 20-21 r 22-23 r 23-25 r 22-26 r 24-25 r 26-28 r 24-28 r 27-31 r 27-29 r 30-31 r 29-33 r 30-32 r 32-33

and Stuttgart RSC 1997 ECP for Co (III) have been reported in Table 5. In accordance Table 5, it is clear that Sum of Mulliken charges and Sum of Mulliken spin densities of [CoCl6]3- under six different loops of B18N18 nano ring

*HRPHWULFDO TXDQWLWLHV Bond Lengths Angle ID c

1.414 1-4-2 1.414 4-2-34 1.293 2-34-35 1.293 34-35-36 1.459 35-36-1 1.459 36-1-4 1.459 9-8-6 1.459 8-6-7 1.293 6-7-3 1.293 7-3-5 1.414 3-5-9 1.414 5-9-8 1.459 12-16-14 1.459 16-14-10 1.293 14-10-11 1.293 10-11-13 1.414 11-13-12 1.414 13-12-16 1.459 21-20-18 1.459 20-18-19 1.293 18-19-15 1.293 19-15-17 1.414 15-17-21 1.414 17-21-20 1.459 24-28-26 1.459 28-26-22 1.293 26-22-23 1.293 22-23-25 1.414 23-25-24 1.414 25-24-28 1.459 33-32-30 1.459 32-30-31 1.293 30-31-27 1.293 31-27-29 1.414 27-29-33 1.414 29-33-32

Bond Angles 91.014 147.316 103.620 125.522 103.620 147.316 91.019 147.318 103.607 125.530 103.607 147.318 91.027 147.312 103.602 125.513 103.602 147.312 91.014 147.316 103.620 125.522 103.620 147.316 91.019 147.318 103.607 125.530 103.607 147.318 91.027 147.312 103.602 125.513 103.602 147.312

are -3.0 and 4.0 respectively. *HRPHWULFDO TXDQWLWLHV RI GLIIHUHQW ORRSV RI %18N18 nano ring inclusive embedded [CoCl6]3- in the nano ring at the level of B3LYP theory and EPR-II basis set for B,N, Cl atoms and Aldrich’s VTZ basis set and 99

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Khaleghian M et al

Stuttgart RSC 1997 Effective Core Potential for Co (III) have been reported in Table 6.

other support of this research, provided by the Islamic Azad University, Islamshahr Branch, Tehran, Iran.

4. CONCLUSIONS

REFERENCES

In this study, Density functional theory calculations with EPR-II basis sets have been used to determination electrostatic non-bonded interaction. Relative energies, HOMO-LUMO bond gaps, total atomic charges of complex in six different loops have been HPSOR\HG WR GHWHFW DQG FKDUDFWHUL]H WKH K\SHUÂ¿QH structural properties of nano ring-complex system. In accordance with Table 1, [CoCl6]3- complex with ZHDN Â¿HOG OLJDQGV H[KLELWV WKH -DKQÂ±7HOOHU GLVWRUWLRQ ,Q DFFRUGDQFH ZLWK 7DEOH GHÂ¿QLWLRQ WKH EDQG JDS RI [CoCl6]3- to 0.18716 a.u. and [CoCl6]3- is insulators. In accordance with NICS values of Table 3, itâ&#x20AC;&#x2122;s elaborated that loops1,3 and 5 have similar NICS values that is equal to -10.1058 and loops 2,4 and 6 have similar NICS values that is equal to -10.1189. So, that if the NICS values would be more negative, the aromaticity and magnetism of the loop is more.

5RJHUV . 0 )RZOHU 3 : 6HLIHUW * Chem. Phys. Lett., 332 (2000), 43. =KX + < 6FKPDO] 7 * .OHLQ ' - Int. J. Quantum Chem., 63 (1997), 393. 3. Manolopoulos D.E, Fowler P.W., Chem. Phys. Lett., 187 (1991), 1. 4. Zope R.R., Dunlap B.I., Chem. Phys. Lett., 386 (2004), 403. 5. Zhang R., Huyskensd T.Z., Ceulemeans A., Nguyen M.T., Chem. Phys., 316 (2005), 35. 6. Amiri A., Monajjemi M., Ketabi S., Phys. Chem. Liq., 45 (2007), 425. 7. Monajjemi M., Azad M.T., Haeri H.H., Zare K., Hamedani Sh., J. Chem. Res., 2003 (2003), 454. 8. Reed A.E., Weinhold F., JACS, 107 (1985), 1919. 9. Monajjemi M., Khaleghian M., J. Cluster Sci., 22 (2011), 673.

ACKNOWLEDGEMENT 7KH DXWKRUV JUDWHIXOO\ DFNQRZOHGJH WKH Â¿QDQFLDO DQG

AUTHOR (S) BIOSKETCHES Mehrnoosh Khaleghian, Assistant Professor, Department of Chemistry, Islamshahr Branch, Islamic Azad University, Tehran, Iran Email: mehr_khaleghian@yahoo.com Fatemeh Azarakhshi, Assistant Professor, Department of Chemistry, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran Gholamreza Ghshami, Instructor, Department of Engineering, Islamshahr Branch, Islamic Azad University, Tehran, Iran

100

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ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Facile Knoevenagel condensation Using Sulfonic Acid Functionalized Nanoporous silica (SBA-Pr-SO3H) Ghodsi Mohammadi Ziarani1*, Faezeh Aleali1, Negar Lashgari2, Alireza Badiei2 1

Department of Chemistry, Alzahra University, P. O. Box 19938939973, Tehran, Iran 2

School of Chemistry, College of Science, University of Tehran, Tehran, Iran Received: 14 February 2015; Accepted: 18 April 2015

ABSTRACT Knoevenagel condensation between barbituric acid and aldehyde was investigated in the presence of sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) and resulted in the formation of arylidene and bis-arylidene barbiturates. Excellent yields and short reaction times are related to the high efficiency of SBA-Pr-SO3H that the reactions take place easily in its nano-pores. SBA-Pr-SO3H as an efficient heterogeneous nanoporous solid acid catalyst which was prepared by silica functionalization with (3-mercaptopropyl) trimethoxysilane followed by oxidation with H2O2, can be easily removed from the reaction mixture by simple filtration, and also recovered and reused without noticeable loss of reactivity. Keywords: Arylidene barbiturates; Barbituric acid; Functionalized SBA-15; Heterogeneous acid catalyst; Knoevenagel condensation

1. INTRODUCTION Barbituric acid is a strong organic acid, having a pKa =4.01 in water. It has got an "active" methylene group and can be involved in condensation reactions with aldehydes or ketones that do not contain an Îą-hydrogen [1]. The general type of this reaction is called the Knoevenagel condensation. Knoevenagel condensation is a facile and versatile method for the formation of carbon-carbon double bond like arylidene barbiturates [2]. Generally, the reaction is catalyzed by bases [3], ionic liquids [4], amino acids [5], basic MCM-41 silica [6], Na-SBA-1 [7], Ni-SiO2 [8], and some acidic condition (*) Corresponding Author - e-mail: gmohammadi@alzahra.ac.ir

such as sulfuric acid [9] and PEG-OSO3H [10]. The derivatives of barbituric acid that are known as barbiturates have special places in pharmaceutical chemistry because of their biological activities in hypnotic, sedative, and anaesthetic drugs [11] and antitumor [12] and anticancer treatments [13]. Arylidene barbiturates have been reported to have various biological activities such as antimicrobial, antiurease, and antioxidant activities [14]. They may be synthesized by Knoevenagel condensation reaction of barbituric/thiobarbituric acid with various aldehydes. In this study,

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 79-85

in continuation of our studies towards using nanoporous solid catalysts in organic reactions [15-18], we used a kind of solid acid catalyst, SBA-Pr-SO3H, as a heterogeneous Bronsted acid with efficient and important advantages such as high surface area, great wall thickness, controllable and narrowly distributed pore size, and high thermal stability [19]. It was observed that SBA-Pr-SO3H improved the reaction condition to access arylidene barbiturates via Knoevenagel and bis Knoevenagel condensation reactions.

2. MATERIALS AND METHODS The chemicals employed in this work were obtained from Merck Company (Germany) and used without further purifications. IR spectra were recorded from KBr disk using an FT-IR Bruker Tensor 27 instrument. Melting points were measured using the capillary tube method with an Electrothermal 9200 apparatus. GC-Mass analysis (Gas chromatography–mass spectrometry) was performed on a GC-Mass model: 5973 network mass selective detector, GC 6890 Agilent. SEM analysis was performed on a Philips XL-30 field-emission scanning electron microscope operated at 16 kV, while TEM was carried out on a Tecnai G2 F30 at 300 kV. 2.1. Preparation of catalyst According to our previous report [20], the nanoporous compound SBA-15 was synthesized and functionalized and the modified SBA-Pr-SO3H was used as a nanoporous solid acid catalyst in the following reaction. 2.2. General procedure for the preparation of bisarylidene barbiturate 4a-c A mixture of barbituric acid (2 mmol, 0.26 g), terephthalaldehyde (1 mmol, 0.13 g) and SBA-Pr-SO3H (0.02 g) was refluxed in water (4 mL) for the appropriated length of time, as mentioned in Table 2. After completion of the reaction, as indicated by TLC, the generated solid product was dissolved in hot dimethylformamide (DMF), filtered for removing the catalyst and then the filtrate was cooled to afford the pure product. The catalyst was washed subsequently with 80

Mohammadi Ziarani and et al.

diluted acid solution, distilled water and then acetone, dried under vacuum and reused several times without significant loss of activity. 2.3. General procedure for the preparation of arylidene barbiturate 5a-d A mixture of barbituric acid (1 mmol, 0.13 g), aldehyde (1 mmol) and SBA-Pr-SO3H (0.02 g) was refluxed in water (4 mL) for the appropriated length of time, as mentioned in Table 2. After completion of the reaction, as indicated by TLC, the generated solid product was dissolved in hot ethanol, filtered for removing the catalyst and then the filtrate was cooled to afford the pure product. 2.4. Spectral data of products 5,5'-(1,4-Phenylenebis(methanylylidene))bis(pyrimidin-2,4,6(1H,3H,5H)-trione) (4a) IR (KBr, cm-1): υmax= 3205, 3093, 1746, 1678, 1575, 1440, 1408, 1210, 815. MS (m/z (%)): 354 (M+, 1.8), 319 (20), 312 (11), 55 (100). 5,5'-(1,4-Phenylenebis(methanylylidene))bis(1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione) (4b) IR (KBr, cm-1): υmax= 2960, 1675, 1538, 1457, 1424, 1378, 1087, 752. 5,5'-(1,4-Phenylenebis(methanylylidene))bis(2-thioxodihydropyrmidine-4,6(1H,5H)-dione) (4c) IR (KBr, cm-1): υmax= 3138, 2920, 1662, 1565, 1527, 1421, 1380, 1155, 521. 5-(4-Methoxyphenyl)methylenebarbituric acid (5a) IR (KBr, cm-1): υmax= 3208, 3069, 2922, 1729, 1674, 1601, 1548, 1508, 1460, 1435, 1400, 1346, 1306, 1269, 1211, 1179, 1080, 1048, 1013, 749, 518. 5-Phenylmethylene-1,3-dimethylbarbituric acid (5b) IR (KBr, cm-1): υmax= 3116, 3030, 2922, 2852, 1671, 1580, 1562, 1447, 1419, 1378, 1358, 1299, 1267, 1212, 1182, 1148, 1069, 831, 794, 771, 502. 5-(4-Chlorophenyl)methylenethiobarbituric acid (5c) IR (KBr, cm-1): υmax= 3108, 2921, 1626, 1564, 1491, 1442, 1383, 1330, 1286, 1206, 1140, 1092, 1012, 870, 831, 793, 529.

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 2 (2015), 79-85

R N

X R 2

O N

N O

X N

R= H, CH3 X= O, S

3-10 min 93-96%

O 1

SBA-Pr-SO3H H2O reflux

R O

1 X= O,S R= H, CH3 R1= H, Cl, OMe

R1 3

N R 4a-c R N

X N

2-5 min 94-97% R1

5a-d

Scheme 1: Synthesis of arylidene and bis-arylidene barbiturates.

5-(4-Methoxyphenyl)methylenethiobarbituric acid (5d) IR (KBr, cm-1): υmax= 3057, 2921, 1696, 1651, 1600, 1562, 1507, 1431, 1391, 1343, 1310, 1268, 1210, 1177, 1150, 1002, 871, 570.

3. RESULTS AND DISCUSSION In this investigation, the synthesis of arylidene 5 and bis-arylidene barbiturates 4 from the condensation of barbituric acid derivatives 1 and aldehydes 2-3 in the presence of SBA-Pr-SO3H as a heterogeneous nano-catalyst under reflux condition was studied (Scheme 1).

In order to achieve optimum conditions, we initially investigated the reaction of barbituric acid 1 and terephthalaldehyde 2 as a model reaction under reflux conditions in acetic acid and H2O and solvent-free conditions. The best result was obtained under reflux conditions in water after 4 minutes with high yield (95%) in the presence of the optimum quantity of SBA-Pr-SO3H (0.02 g). As shown results in Table 1, the presence of the catalyst was found to give higher yield in shorter reaction time. This reaction condition was developed with three types of barbituric acids and four types of substituted aldehydes in a molar ratio of (2:1) and (1:1). Corresponding arylidene and bisarylidene barbiturates were successfully prepared in 92-97%. It was observed that the nature of substituent

Table 1: The optimization of reaction condition in the synthesis of bis-arylidene barbiturate 4aa.

Entry 1c 2 3

Solvent

Temperature (°C)

Time (min)

Yieldb (%)

CH3CO2H H2O Neat

Reflux Reflux 70 °C

30 4 90

65 95 85

Reaction conditions: barbituric acid (2 mmol), terephthalaldehyde (1 mmol), SBA-Pr-SO3H (0.02 g); bIsolated yield; cCatalyst free a

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Mohammadi Ziarani and et al.

Table 2: SBA-Pr-SO3H catalyzed the synthesis of arylidene and bis-arylidene barbiturates.

Entry

Aldehyde

Product H N

Time (min)

Yield (%)

MP (Â°C)

MP (Lit.)

>300

>300 [10]

>300

>300 [10]

>300

>300 [10]

283-285

276 [21]

156-157

159-160 [22]

288-290

291-292 [23]

>300

>300 [23]

O NH

N H

4a Me N

O Me

N O O

N N Me

Me O

4b S

H N

HN O

O NH

O N H

4c H N

O NH

OMe

5a O

Me N

5b O

H N

S NH

5c H N

S NH

O OMe

OMe

5d 82

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Table 3: Comparison of different conditions in the synthesis of bis-arylidene barbiturate 4a.

Entry 1

Catalyst H2SO4

Solvent CH3CO2H

Condition Reflux

Time (min) 60

Yield (%) 93

Year 2003 [9]

PEG-OSO3H

Neat

Stir. (70Â°C)

2013 [10]

Lipase

EtOH

Stir. (40-45Â°)

300

2013 [24]

SBA-Pr-SO3H

H2O

Reflux

This work

X R HO

SBA-Pr-SO3H

O R

O 2

N O

-2 H2O N

R OH

6 X N

R N

R OH

N O

N R

R X

Scheme 2: Plausible mechanism for synthesis of bis-arylidene barbiturates in the presence of SBA-Pr-SO3H.

on the aromatic ring of aldehydes did not affect the yield of desired products. The results are summarized in Table 2. The progress of the reaction was monitored by TLC. Upon completion of the reaction, the mixture was cooled to room temperature; the resulting solid product of bis-arylidene barbiturate derivatives were dissolved in hot dimethylformamide (DMF) and arylidene barbiturate derivatives were dissolved in hot ethanol. After filtration of catalyst and cooling of the filtrate, the pure crystals were obtained. The catalyst

was subsequently washed with diluted acid solution, distilled water and then acetone, dried under vacuum and re-used for several times without significant loss of activity. Table 3 illustrates a comparison of the effectiveness of various catalysts used in the synthesis of bis-arylidene barbiturate 4a. It is clear from Table 3 that SBA-Pr-SO3H is one of the most efficient and less time-consuming catalysts, when compared with other existing methods. The suggested mechanism for the SBA-Pr-SO3H catalyzed formation of the product 4 is shown in

Figure 1: SEM image (left) and TEM image (right) of SBA-Pr-SO3H.

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aldehydes in excellent yield. The advantages offered by using SBA-Pr-SO3H as a nano heterogeneous catalyst in this reaction are compatibility, reusability, high selectivity, and non-corrosiveness. This method provides desired products in short reaction times and high yields together with use of water as the solvent under green conditions.

ACKNOWLEDGEMENT Figure 2: Reusability of SBA-Pr-SO3H in the synthesis of compound 4a.

Scheme 2. Protonation of a carbonyl group of terephthalaldehyde 2 by the solid acid catalyst activates it toward nucleophilic attack of barbituric acid 6. Subsequently elimination of water affords the corresponding bis-arylidene barbiturates 4 (Scheme 2). It is interesting that the reaction easily occurs in water although the mechanism involves a net dehydration. It was proposed that water helps the dissociation of thiobarbituric acid due to its high ε value, 78, which generates the nucleophilic species being able to attack the carbonium of the aldehyde [23]. Figure 1 shows the SEM and TEM images of SBAPr-SO3H. SEM image (Figure 1, left) illustrates uniform particles about 1 μm which the same morphology was observed for SBA-15 and TEM image (Figure 1, right) demonstrated parallel channels, that resemble the pore configurations of SBA-15. The reusability of the catalyst was investigated under optimized conditions for the synthesis of the model compound 4a. As it is shown in Figure 2, the process of recycling was completed four times and no significant decrease in activity was observed. The yields for the four runs were found to be 94%, 88%, 77%, and 70%, respectively.

4. CONCLUSIONS In summary, we have described a simple and efficient procedure for the synthesis of arylidene barbiturate derivatives using SBA-Pr-SO3H as a catalyst via Knoevenagel condensation reaction of barbituric acid and 84

We gratefully acknowledge for financial support from the Research Council of Alzahra University and University of Tehran.

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AUTHOR (S) BIOSKETCHES Ghodsi Mohammadi Ziarani, Professor, Department of Chemistry, Alzahra University, P.O.Box 19938939973, Tehran, Iran, E-mail: gmohammadi@alzahra.ac.ir Faezeh Aleali, M.Sc., Department of Chemistry, Alzahra University, P.O.Box 19938939973, Tehran, Iran Negar Lashgari, Ph.D., School of Chemistry, College of Science, University of Tehran, Tehran, Iran Alireza Badiei, Professor, School of Chemistry, College of Science, University of Tehran, Tehran, Iran