Copper(II) complex of (±)trans-1,2-cyclohexanediamine azo-linked Schiff base ligand encapsulated in the nanocavity of zeolite-Y for the catalytic oxidation of olefins J. Serb. Chem. Soc. 81 (2) 153–162 (2016) UDC 546.562+547.592’415.1+547.576: JSCS–4835 542.9+547.571+547.551:66.094.3.097 Original scientific paper 153 Copper(II) complex of (±)trans-1,2-cyclohexanediamine azo-linked Schiff base ligand encapsulated in the nanocavity of zeolite-Y for the catalytic oxidation of olefins MARYAM LASHANIZADEGAN*, SAHAR SHAYEGAN and MARZIEH SARKHEIL Department of Chemistry, Faculty of Physics and Chemistry, Al-zahra University, P. O. Box 1993893973, Tehran, Iran (Received 8 July, revised 2 October, accepted 7 October 2015) Abstract: A Schiff base ligand derived from 2-hydroxy-5-(phenylazo)-benzal- dehyde and (±)trans-1,2-cyclohexanediamine (H2L) and its corresponding Cu(II) complex (CuL) were synthesized and characterized by FT-IR, UV–Vis and 1H-NMR spectroscopy. The copper Schiff base complex was encapsulated in the nanopores of zeolite-Y (CuL-Y) by the flexible ligand method and its encapsulation was confirmed by different studies. The homogeneous and the corresponding heterogeneous catalysts were used for the oxidation of different alkenes with tert-butyl hydroperoxide. Under the optimized reaction con- ditions, the oxidation of cyclooctene, cyclohexene, styrene and norbornene catalyzed by CuL gave 89, 63, 46 and 13 % conversion, respectively. These olefins were oxidized efficiently with 50, 96, 95 and 92 % conversion, respect- ively, in the presence of CuL-Y. Comparison of the catalytic behavior of CuL and CuL-Y showed the higher catalytic activity and selectivity of the hetero- geneous catalyst with respect to the homogenous one. Keywords: catalyst; 2-hydroxy-5-(phenylazo)-benzaldehyde; styrene; zeolite; encapsulated. INTRODUCTION Various transition metal complexes have been used in the catalytic oxidation of organic substrates.1 In particular, the catalysis of alkene oxidation by tran- sition metal complexes is an area of current interest.2,3 Schiff base ligands are easily synthesized by the condensation of amines and aldehydes.4 The develop- ment of the salen transition metal complexes has provided a useful catalyst for epoxidation reactions. In 1990, the Jacobsen5 and Katsuki6 groups first reported that Mn(III) salen complexes were applied in the epoxidation of non-function- alized alkenes. They extensively studied the steric7 and electronic effects8 of sub- * Corresponding author. E-mail: m_lashani@alzahra.ac.ir doi: 10.2298/JSC150708085L _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ 154 LASHANIZADEGAN, SHAYEGAN and SARKHEIL stituent groups on the salen ligand that could affect the enantioselectivity and rate of this reaction.9 Schiff bases having both azo and azomethine groups are called azo Schiff bases. These compounds are used in the textile, leather and plastic industries10–12 and have the potential for use in electronic and drug delivery applications.13,14 Azo compounds are useful in analytical applications, e.g., as complexometric and pH indicators.15 Moreover, these derivatives show biolog- ical activities.16,17 A few azo Schiff base complexes were reported to be cat- alytically active towards oxidation.18 Therefore, it is of interest to study azo- -linked compounds as catalysts. Immobilization of homogeneous catalysts onto or into an insoluble solid, which can be either an inorganic solid or an organic polymer, provides higher activity, selectivity and reusability of catalysts.19–22 Several examples of hetero- genization of homogeneous catalysts onto some inorganic supports, such as MCM-41,23,24 SBA-1525,26 and zeolites27–29 have been reported. Among the different metal complexes, Cu(II) Schiff base complexes are known for their oxygenation reactions. Various copper complexes catalyzed ole- fin oxidation reactions in homogeneous30,31 and heterogeneous32,33 media and the mechanisms of these reactions are well established. In this study, the copper(II) complex of an azo-linked Schiff base ligand was encapsulated in the nanocavity of zeolite-Y and the catalytic activity of the homogeneous and heterogeneous catalysts in the oxidation of various olefins with tert-butyl hydroperoxide (TBHP) was investigated. EXPERIMENTAL Materials All starting materials and solvents were purchased from Merck and were used without further purification. Physical measurements IR spectra (KBr discs, 500–4000 cm-1) were recorded using a Bruker FTIR model Tensor 27 spectrometer. UV–Vis absorption spectra were recorded on a Perkin–Elmer Lambda 35 spectrophotometer. 1H-NMR spectra were collected on a Bruker FT-NMR 250 MHz spectrometer in CDCl3 with TMS as the internal reference. X-Ray diffractograms were recorded using a Seifect 3003 PTS diffractometer with a Cu-Kα target. The reaction products of oxidation were determined and analyzed by GC–MS Quadrupole Agilent 5973 MSD spectrometer. Preparation of 2-hydroxy-5-(phenylazo)-benzaldehyde 4-(Benzeneazo)salicylaldehyde was prepared using a standard procedure.34 Preparation of the ligand (H2L) (±)trans-1,2-Cyclohexanediamine (0.5 mmol, 0.06 g) in 5 mL ethanol was added to a solution of 2-hydroxy-5-(phenylazo)-benzaldehyde (1 mmol, 0.23 g) in 10 mL ethanol and chloroform at a ratio of 2 to 1. The resulting mixture was refluxed for 4 h. Finally, the preci- pitate of ligand (H2L) was recovered by filtration, washed with ethanol and dried. The ligand was recrystallized from ethanol to give the pure product (Fig. 1). Yield: 57 %. _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ COPPER(II) COMPLEX AS CATALYST IN OLEFIN OXIDATION 155 Fig. 1. Structure of the ligand H2L. Preparation of CuL The CuL complex was prepared by adding a chloroform solution of the ligand (H2L) (1.5 mmol, 0.29 g) to an ethanolic solution of Cu(CH3COO)2⋅H2O (1.5 mmol, 0.79 g). The resulting mixture was refluxed for about 2 h and a brown precipitate was obtained. Finally, the precipitate of the complex was recovered by filtration, washed with ethanol and dried at room temperature. Yield: 85 %. Some physical and spectral data for H2L and CuL are given in Supplementary material to this paper. Incorporation of the copper(II) in Na-Y (metal exchanged zeolite-Y) The Cu-Y was prepared using the standard procedure.35 Na zeolite-Y (4 g) was sus- pended in 100 mL distilled water that contained copper(II) nitrate (4 mmol). The mixture was then stirred for 24 h. The solid was filtered and washed with deionized water and dried at room temperature to give a light blue powder of Cu-Y. Immobilization of H2L in Cu-Y Cu-Y (0.6 g) and ligand H2L (0.1 g) were mixed in 50 mL of acetonitrile and the reaction mixture was refluxed for 7 h in an oil bath under constant stirring. The resulting material was removed and extracted with acetonitrile using a Soxhlet extractor to remove the unreacted ligand from the cavities of the zeolite and the surface of the zeolite along with neat complex, if any. The non-complexed metal ions present in the zeolite were removed by exchanging with an aqueous 0.01 M NaCl solution. The resulting solid was finally washed with hot distilled water until no precipitation of AgCl was observed in filtrate reacted with AgNO3 solution. The final solid was then dried at 150 °C for several hours until a constant weight was achieved (Fig. 2). Fig. 2. Preparation of encapsulated complex in the supercages of zeo- lite-Y. _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ 156 LASHANIZADEGAN, SHAYEGAN and SARKHEIL Homogeneous oxidation To a solution of cyclooctene (10 mmol) and CuL (10 mg, 0.02 mmol) in CH3CN (5 mL), TBHP (25 mmol) was added. The resulting mixture was refluxed and the products were collected at different time intervals, identified and quantified by GC and verified by GC–MS. Heterogeneous oxidation Catalyst (20 mg), cyclooctene (10 mmol) and TBHP (25 mmol) were mixed in 5 mL of CH3CN and the reaction mixture was refluxed under continuous stirring in an oil bath for 8 h. The products were collected at different time intervals, identified, quantified by GC, and verified by GC–MS. RESULTS AND DISCUSSION Spectral studies In the IR spectrum of the ligand (H2L), a sharp band due to the azomethine ν(C=N) appeared at 1630 cm–1. The bands at 2853 and 2919 cm–1 are indicative of the presence of 1,2-cyclohexanediamine.36,37 The band due to ν(C=N) in H2L was shifted to a lower wave number and appeared at 1608 cm–1 in CuL. This indicates the involvement of azomethine nitrogen in the coordination to the cop- per center. Moreover, ν(C=N) of CuL-Y appeared at 1633 cm–1. This obser- vation suggested that the structure of CuL in the zeolite is not identical to that of the neat complex due to some host–guest interactions. The IR spectrum of the hybrid material showed an intense band at 1022 cm–1 attributable to the asym- metric stretching of Al–O–Si chain of the zeolite. The symmetric stretching and bending frequency bands of Al–O–Si framework of zeolite appeared at 789 and 458 cm–1, respectively.38 The X-ray powder diffraction patterns of CuL-Y and Na-Y were essentially similar except the intensities were weaker in the immobilized complex (Fig. 3). This observation indicates that the framework of the zeolite had not structurally changed during the immobilization. The 1H-NMR spectrum of the ligand (H2L) was recorded using CDCl3 solvent. Hydrogen atoms of the azomethine groups of H2L appeared at δ 8.23– –8.41 ppm. The hydrogen atoms of the CH2/CH groups in the cyclohexane ring were observed in the δ 1.49–3.46 ppm range. The phenolic OH protons were found at 10.05 and 11.35 ppm. The aromatic protons appeared in the range δ 7.00–7.94 ppm as a multiplet.36,37,39 The electronic spectrum of CuL consisted of one broad d–d transition band at 524 nm, as is usual for square planar geometry Cu(II). The higher energy bands were due to π–π* or n–π* transition.40 The catalytic oxidation of alkenes The catalytic performance of CuL in the oxidation of cyclooctene, as a model substrate, with H2O2 and TBHP as oxidizing agents was investigated. The results of a series of blank experiments are shown in Table I, which confirmed the presence of the catalyst is essential for the oxidation of alkenes. _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ COPPER(II) COMPLEX AS CATALYST IN OLEFIN OXIDATION 157 Fig. 3. XRD patterns of Na-Y, Cu-Y and CuL-Y. TABLE I. Blank experiments; reaction conditions: substrate, 10 mmol, TBHP, 25 mmol, acetonitrile, 5 mL; the reactions were run for 8 h under reflux Entry Alkene Conversion, % Selectivity, % 1 Cycloctene 5 50a 2 Cyclohexene 7 64b 3 Styrene 5 72c 4 Norbornene 9 58d aCyclooctene oxide; b2-cyclohexen-1-ol; cbenzoic acid; dnorbornene epoxide Different reaction parameters, such as reaction time, reaction solvent, cat- alyst concentration, the nature and the concentration of the oxidant that may affect the conversion and selectivity of the reaction were optimized. The influence of reaction time in the catalytic oxidation of cyclooctene by CuL is illustrated in Fig. 4. It was observed that oxidation of cyclooctene required 8 h for maximum conversion. The effect of the nature of the solvent in the catalytic activity of CuL for the oxidation of cyclooctene was studied. Thus, acetonitrile, ethanol, dichloromethane and chloroform were used and the highest conversion was obtained in acetonitrile (Table II). The higher conversions in acetonitrile (69 %) relative to the others possibly may be due to the polarity, hyd- rophilicity, size of the solvent molecule and higher boiling point of acetonitrile.41 The effect of amount of catalyst was investigated in the oxidation of cyclooctene. As seen in Table III, the highest conversion was obtained with 0.04 mmol (0.02 g) of catalyst. Different amounts of oxidant (TBHP) were studied in _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ 158 LASHANIZADEGAN, SHAYEGAN and SARKHEIL the oxidation of cyclooctene (Table IV). The results indicate that the highest conversion (89 %) was obtained at 1:2.5 mole ratio of cyclooctene to TBHP. Fig. 4. Effect of the reaction time on the oxidation of cyclooctene. Reac- tion conditions: cyclooctene, 10 mmol, CuL, 0.02 mmol, TBHP, 25 mmol, solvent, CH3CN, 5 mL, under reflux. TABLE II. The influence of various solvents on the oxidation of cyclooctene in the presence of CuL; reaction conditions: cyclooctene, 10 mmol, CuL, 0.02 mmol, TBHP, 25 mmol and solvent, 5 mL; the reactions were run for 8 h under reflux Entry Solvent Conversion% Selectivity, % Cyclooctene oxide 2-Cycloocten-1-one Other products 1 Acetonitrile 69 63 34 3 2 Ethanol 28 60 40 0 3 Chloroform 18 57 32 11 4 Dichloromethane 16 49 43 8 TABLE III. The effect of the amount of CuL on the oxidation of cyclooctene; reaction con- ditions: cyclooctene (10 mmol), CH3CN (5 mL) and TBHP (25 mmol); the reactions were run for 8 h under reflux Entry CuL mmol Conversion % Selectivity, % Cyclooctene oxide 2-Cycloocten-1-one Other products 1 0.02 69 63 34 3 2 0.04 89 53 38 9 3 0.06 80 59 37 4 4 0.08 66 65 31 4 TABLE IV. The effect of amount of oxidant (TBHP) on the oxidation of cyclooctene in the presence of CuL; reaction conditions: cyclooctene (10 mmol), CuL (0.04 mmol) and CH3CN (5 mL), the reactions were run for 8 h under reflux Entry TBHP mmol Conversion % Selectivity, % Cyclooctene oxide 2-Cycloocten-1-one Other products 1 20 59 63 35 9 2 25 89 53 38 9 3 30 81 59 37 5 _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ COPPER(II) COMPLEX AS CATALYST IN OLEFIN OXIDATION 159 In order to investigate the effect of the oxidizing agent in the oxidation reac- tion, H2O2 and TBHP were used (Table V). In the presence of TBHP, a higher conversion (89 %) was obtained. TABLE V. The influence of the kind of oxidant on the oxidation of cyclooctene in the presence of CuL; reaction conditions: cyclooctene (10 mmol), CuL (0.04mmol), CH3CN (5 mL), oxidant (25 mmol); the reactions were run for 8 h under reflux Entry Oxidant Conversion % Selectivity, % Cyclooctene oxide 2-Cycloocten-1-one Other products 1 TBHP 89 53 38 9 2 H2O2 23 100 0 0 To establish the general applicability of the method, under the optimized conditions, different olefins were subjected to oxidation in the presence of a catalytic amount of CuL and CuL-Y, the results are given in Tables VI and VII respectively. TABLE VI. Oxidation of olefins using TBHP catalyzed by CuL; reaction conditions: CuL (0.04 mmol), substrate (10 mmol), TBHP (25 mmol), acetonitrile (5 mL); the reactions were run for 8 h under reflux Alkene Conversion, % Selectivity, % Main product Others 89 53a 38b 9 63 60c 40d 0 46 60e 25f 9 13 100g 0 0 aCyclooctene oxide; b2-cycloocten-1-one; ccyclohexene oxide; d2-cyclohexen-1-ol; ebenzaldehyde; fbenzoic acid; gnorbornene epoxide Comparison of the catalytic behavior of the copper Schiff base complex encapsulated in the super cages of zeolite-Y and free CuL showed the higher catalytic activity and selectivity of the heterogeneous catalyst with respect to the homogenous one. When the reaction occurred in the cavity of zeolite, the imp- _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ 160 LASHANIZADEGAN, SHAYEGAN and SARKHEIL rovement of catalysis event was probably due to diffusional selectivity of the reaction and potentially increased stability via site isolation. TABLE VII. Oxidation of olefins using TBHP catalyzed by CuL-Y; reaction conditions: CuL- Y (20 mg), substrate (10 mmol), TBHP (25 mmol), acetonitrile (5 mL); the reactions were run for 8 h under reflux Alkene Conversion, % Selectivity, % Main product Other 50 68a 32b 96 80c 20d 95 80e 20f 92 100g 0 aCyclooctene oxide; b2-cycloocten-1-one; ccyclohexene oxide; d2-cyclohexen-1-ol; ebenzaldehyde; fbenzoic acid; gnorbornene epoxide CONCLUSIONS In summary, the azo Schiff base ligand (H2L) derivative of (±)trans-1,2-cyc- lohexanediamine and 2-hydroxy-5-(phenylazo)-benzaldehyde was prepared. The copper Schiff base complex (CuL) was encapsulated in the nanopores of zeolite- Y (CuL-Y). Furthermore, these heterogeneous and homogeneous catalysts were used for the oxidation of different alkenes with tert-butyl hydroperoxide. Various reaction parameters were investigated and optimized in the oxidation reaction. The oxidation of cyclooctene, cyclohexene, styrene and norbornene catalyzed by CuL gave 89, 63, 46 and 13 % conversion, respectively. Under the heterogeneous conditions, the oxidation of these olefins with 50, 96, 95 and 92 % conversion, respectively, was obtained. It was observed that CuL-Y has higher catalytic acti- vity and selectivity than CuL. This change was specially seen for norbornene. SUPPLEMENTARY MATERIAL Some physical and spectral data for H2L and CuL are available electronically from http://www.shd.org.rs/JSCS/, or from the corresponding author on request. Acknowledgement. Financial assistance from Alzahra University is acknowledged. _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ COPPER(II) COMPLEX AS CATALYST IN OLEFIN OXIDATION 161 ИЗВОД КОМПЛЕКСИ БАКРА(II) СА (±)trans-1,2-ЦИКЛОХЕКСАНДИАМИН ШИФОВОМ БАЗОМ СА АЗО ГРУПОМ, КАО ЛИГАНДОМ, КАПСУЛИРАНИ У НАНОПОРАМА ЗЕOЛИТА-Y КАО КАТАЛИЗАТОРИ ОКСИДАЦИЈЕ ОЛЕФИНА MARYAM LASHANIZADEGAN, SAHAR SHAYEGAN и MARZIEH SARKHEIL Department of Chemistry, Faculty of Physics and Chemistry, Al-zahra University P. O. Box 1993893973, Tehran, Iran Полазећи од 5-(фенилазо)-2-хидроксибензалдехида и (±)trans-1,2-циклохександи- амина синтетисани су Шифова база као лиганд (H2L) и одговарајући Cu(II) комплекс (CuL). За карактеризацију ових једињења коришћене су FT-IR, UV–Vis и 1H-NMR спектроскопске методе. Бакар(II) комплекс је методом флексибилног лиганда капсулиран у нанопoре зеолита-Y (CuL-Y) и ово капсулирање је испитивано различитим методама. Хомогено и хетерогено каталитичко својство овог капсулираног бакар(II) комплекса је коришћено за оксидацију различитих алкена у присуству tert-бутил-хид- ропероксида. Под одговарајућим експерименталним условима, оксидација циклооктена, циклохексена, стирена и норборнена уз каталитичко дејство CuL комплекса се одиграва са 89, 63, 46, односно 13 % конверзијом. Ови олефини су у присуству CuL-Y комплекса веома ефикасно оксидовани са 50, 96, 95, односно 92 % конверзијом. Поређена су каталитичка својства CuL и CuL-Y, при чему је нађено да хетерогена катализа показује веће каталитичко дејство и селективност у односу на хомогену катализу. (Примљено 8. јула, ревидирано 2. октобра, прихваћено 7. октобра 2015) REFERENCES 1. R. G. Sheldon, B. J. Kochi, Metal-Catalyzed Oxidations of Organic Compounds, Academic Press, New York, 1981, p. 1 2. X. Cai, H. Wang, Q. Zhang, J. Tong, Z. Lei, J. Mol. Catal. A: Chem. 383–384 (2014) 217 3. M. Lashanizadegan, Z. Zareian, Catal. Lett. 141 (2011) 1698 4. H. Schiff, Ann. Chem. Pharm Suppl. 3 (1864) 343 5. W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 112 (1990) 2801 6. R. Irie, K. Noda, Y. Ito, N. Matsumoto, T. Katsuki, Tetrahedron Lett. 31 (1990) 7345 7. E. N. Jacobsen, W. Zhang, M. L. Güler, J. Am. Chem. Soc. 113 (1991) 6703 8. L. Cavallo, H. Jacobsen, J. Org. Chem. 68 (2003) 6202 9. E. M. McGarrigle, D. G. Gilheany, Chem. Rev. 105 (2005) 1563 10. S. C. Catino, E. Farris, Concise Encyclopedia of Chemical Technology, Wiley, New York, 1985, p. 142 11. K. Venkataraman, The Chemistry of Synthetic Dyes, Academic Press, New York, 1974, p. 46 12. K. Hunger, Industrial Dyes: Chemistry, Properties, Applications, Wiley–VCH Verlag, Weinheim, 2003, p. 375 13. Y. S. Zhou, L. J. Zhung, X. R. Zeng, J. J. Vital, X. Z. You, J. Mol. Struct. 553 (2000) 25 14. R. Walker, Food Cosmet. Toxicol. 8 (1970) 659 15. S. Patai, The Chemistry of the Hydrazo, Azo and Azoxy Groups, Wiley, London, 1997, p. 234 16. P. Pathak, V. S. Jolly, K. P. Sharma, Orient. J. Chem. 15 (2000) 161 17. H. Xu, X. Zeng, Bioorg. Med. Chem. Lett. 20 (2010) 4193 18. E. Ispir, Dyes Pigm. 82 (2009) 13 _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. Available on line at www.shd.org.rs/JSCS/ 162 LASHANIZADEGAN, SHAYEGAN and SARKHEIL 19. Y. Chang, Y. Lv, F. Lu, F. Zha, Z. Lei, J. Mol. Catal. A: Chem. 320 (2010) 56 20. Y. Chang, X. L. Shi, D. M. Zhu, Y. Liu, Polym. Adv. Technol. 19 (2008) 877 21. S. Sharma, S. Sinha, S. Chand, Ind. Eng. Chem. Res. 51 (2012) 8806 22. Z. Li, R. Tang, G. Liu, Catal. Lett. 143 (2013) 592 23. J. Adhikary, A. Guha, T. Chattopadhyay, D. Das, Inorg. Chim. Acta 406 (2013) 1 24. S. Jana, B. Dutta, R. Bera, S. Koner, Langmuir 23 (2007) 2492 25. X. Wang, G. Wu, W. Wei, Y. Sun, Catal. Lett. 136 (2010) 96 26. Y. Yang, S. Hao, P. Qiu, F. Shang, W. Ding, Q. Kan, React. Kinet., Mech. Catal. 100 (2010) 363 27. M. Ghorbanloo, S. Rahmani, H. Yahiro, Transition Met. Chem. (Dordrecht, Neth.) 38 (2013) 725 28. G. Willingh, H. S. Abbo, S. J. J. Titinchi, Catal. Today 227 (2014) 96 29. H. S. Abbo, S. J. J. Titinchi, Appl. Catal., A 356 (2009) 167 30. S. M. Islam, A. S. Roy, P. Mondal, M. Mubarak, S. Mondal, D. Hossain, S. Banerjee, S. C. Santra, J. Mol. Catal. A: Chem. 336 (2011) 106 31. F. Heshmatpour, S. Rayati, M. Afghan-Hajiabbas, P. Abdolalian, B. Neumüller, Polyhedron 31 (2012) 443 32. H. Hosseini-Monfared, E. Pousaneh, S. Sadighian, S. W. Ng, E. R. T. Tiekink, Z. Anorg. Allg. Chem. 639 (2013) 435 33. A. Bezaatpour, M. Behzad, V. Jahed, M. Amiri, Y. Mansoori, Z. Rajabalizadeh, S. Sarvi, React. Kinet., Mech. Catal. 107 (2012) 367 34. A. Vogel, A Text-Book of Practical Organic Chemistry, Longman, New York, 1956, p. 620 35. S. Koner, Chem. Commun. (1998) 593 36. M. Aslantas, E. Kendi, N. Demir, A. E. S. Abik, M. Tumer, M. Kertmen, Spectrochim. Acta, A 74 (2009) 617 37. M. Lashanizadegan, M. Sarkheil, Main Group Chem. 12 (2013) 15 38. R. M. Barrer, Hydrothermal Chemistry of Zeolite, Academic Press, New York, 1982 39. M. Lashanizadegan, M. Sarkheil, J. Serb. Chem. Soc. 77 (2012) 1589 40. C. M. Liu, R. G. Xiong, X. Z. You, Polyhedron 16 (1997) 119 41. R. Neumann, C. Abu-Gnim, J. Am. Chem. Soc. 112 (1990) 6025. _________________________________________________________________________________________________________________________ (CC) 2016 SCS. All rights reserved. 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