JSCS - Vol 73, No 3

JSCS Vol 73, No. 3

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J. Serb. Chem. Soc. 73 (3) 259 (2008)

EDITOR’S NOTE

In memoriAM: Academician Dragutin M. Dražić

J. Serb. Chem. Soc. 73 (3) 261–270 (2008)
UDC 547.631.6.001+547.384; JSCS–3798; doi: 10.2298/JSC0803261S; Original scientific paper

A convenient preparation of novel benzophenone derivatives
BELGUR S. SUDHA, RAVINDRA R. KAMBLE and SHEENA SHASHIKANTH*

Department of Chemistry and Food Science, Yuvaraja’s College, University of Mysore, Mysore – 570 005, India

*Department of Studies in Chemistry, Manasagangotri, Mysore – 570 006, India

(Received 21 June, revised 18 September 2007)

A simple and high yielding method for the synthesis of novel benzophenone derivatives has been developed starting from ethyl(4-aroylaroxy)acetates. Confirmation for the structures of the newly synthesized compounds was proved by their physical, analytical and spectral data (IR, ¹H-NMR, ¹³C-NMR and MS).

Keywords: aroylaryloxy esters; 2-oxazolines; N-arylacetAMides; HIV reverse transcriptase (RT); antihaemostatic activity.

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J. Serb. Chem. Soc. 73 (3) 271–282 (2008)
UDC 547.979.7+52–74:547.284.3+547.216; JSCS–3709; doi: 10.2298/JSC0803271Z; Original scientific paper

Bleaching of chlorophylls by UV irradiation in vitro: the effects on chlorophyll organization in acetone and n-hexane
JELENA ZVEZDANOVIC and DEJAN MARKOVIC
Faculty of Technology, 16000 Leskovac, Serbia

(Received 17 May, revised 8 August 2007)

The stability of chlorophylls toward UV irradiation was studied by Vis spectrophotometry in extracts containing mixtures of photosynthetic pigments in acetone and n-hexane. The chlorophylls underwent destruction (bleaching) obeying first-order kinetics. The bleaching was governed by three major factors: the energy input of the UV photons, the concentration of the chlorophylls and the polarity of the solvent, implying different molecular organizations of the chlorophylls in the two solvents.

Keywords: chlorophyll; UV-irradiation; kinetics; acetone; hexane.

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J. Serb. Chem. Soc. 73 (3) 283–297 (2008)
UDC *Stevia rebaudiana+581.45:633.879+547.384:665.52/.54(497.113); JSCS–3710; doi: 10.2298/JSC0803283M; Original scientific paper

Chemical composition of leaf extracts of Stevia rebaudiana Bertoni grown experimentally in Vojvodina
IVANA S. MARKOVIC, ZOLTAN A. DJARMATI* and BILJANA F. ABRAMOVIC**
College of Technology, Djordja Stratimirovica 23, 23000 Zrenjanin, Serbia

*Bioecological Center, Petra Drapsina 1, 23000 Zrenjanin Serbia

**Faculty of Science, Department of Chemistry, Trg D. Obradovica 3, 21000 Novi Sad, Serbia

(Received 8 June, revised 9 August 2007)

The chemical composition of leaf extracts of Stevia rebaudiana Bertoni, grown for the first time on an experimental field near Zrenjanin, was exAMined by GC–MS. The tested plant material was harvested in September of 2002. To analyze the chemical composition of the lipophilic components of the plant leaves, essential oils and ethyl acetate extract were isolated. Qualitative analysis of the essential oil obtained by hydrodistillation showed that AMong the identified 88 compounds, the majority were mono- and sesquiterpenes (50 types identified). By analysing the ethyl acetate extract, the presence of fatty acids (present as free and as esters), n-alkanes, n-alkenes, cyclic alkanes, alcohols, aldehydes, ketones, etc. was ascertained. Sesquiterpenes prevailed AMong the terpenes (50 types identified). Further constituents identified in ethyl acetate extract included sterols. Nerol, b-cyclocitral, safranal, aromadendrene, a-AMorphene and T-muurolol were identified for the first time in this species, with match values over 90 %. Taking into consideration that these terpenes were identified for the first time in this species, it is obvious that Stevia rebaudiana grown in this area possesses certain specific characteristics that can be ascribed to cultivation on a domestic plantation.

Keywords: Stevia rebaudiana Bertoni; essential oil; ethyl acetate extract; GC–MS; composition.

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J. Serb. Chem. Soc. 73 (3) 299–305 (2008)
UDC *Teucrium montanum:665.52/.54:615.281:547.261; JSCS–3711; doi: 10.2298/JSC0803299V; Original scientific paper

The chemical composition of the essential oil and the antibacterial activities of the essential oil and methanol extract of Teucrium montanum
NENAD VUKOVIC, TANJA MILOSEVIC, SLOBODAN SUKDOLAK and SLAVICA SOLUJIC
Department of Chemistry, Faculty of Science, University of Kragujevac, Radoja Domanovica 12, P. O. Box 12, 34000 Kragujevac, Serbia

(Received 11 June, revised 3 September 2007)

This study was designed to exAMine the chemical composition of the essential oil and the in vitro antibacterial activities of the essential oil and methanol extract of Teucrium montanum. The inhibitory effects of the essential oil and the methanol extracts of Teucrium montanum were tested against thirteen bacterial species using the disc-diffusion method. GC/MS analyses revealed that the essential oil contained mainly sesquiterpenes, such as d-cadinene (17.19 %), b-selinene (8.16 %) and a-calacorene (4.97 %). The highest activities were obtained with the essential oil of Teucrium montanum against K. pneumoniae, B. subtilis, B. mycoides, E. cloaceae and A. chlorococcum. In addition, comparison of the antibacterial activities of the essential oil and the methanol extract showed that the essential oil exhibited the stronger antibacterial activities.

Keywords: essential oil; Teucrium montanum; antibacterial activity.

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J. Serb. Chem. Soc. 73 (3) 307–310 (2008)

UDC 635.71:581.19:665.52/.54(815.3); JSCS–3712; doi: 10.2298/JSC0803307P; Note

NOTE

Chemical composition of Thymus vulgaris L. (thyme) essential oil from the Rio de Janeiro State (Brazil)

ALEXANDRE PORTE and RONOEL L. O. GODOY*

Instituto de Tecnologia – Universidade Federal Rural do Rio de Janeiro, BR 465, km 47, Seropédica, Cep 23890-000, Rio de Janeiro, Brazil

*Embrapa Agroindústria de Alimentos, Avenida das Américas, 29501, Guaratiba, Cep 23020-470, Rio de Janeiro, Brazil

(Received 5 June 2007)

The essential oil from fresh leaves of Thymus vulgaris L. from Rio de Janeiro State, Brazil, was isolated by hydrodistillation and analyzed through a combination of GC and GC/MS. Compounds representing 95.1 % of the oil were identified. Thirty-nine constituents were detected, of which twenty-eight were identified according to their chromatographic retention indices and mass spectra. The major constituents of the oil were thymol (44.7 %), p-cymene (18.6 %) and g-terpinene (16.5 %).

Keywords: Thymus vulgaris; thyme; essential oil; thymol; p-cymene.

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J. Serb. Chem. Soc. 73 (3) 311–319 (2008)

UDC 539.6:517.58:519.17–124; JSCS–3713; doi: 10.2298/JSC0803311E; Original scientific paper

Hosoya polynomial of zigzag polyhex nanotorus

MEHDI ELIASI and BIJAN TAERI

Department of Mathematical Sciences, Isfahan University of Technology, Isfahan 84156-83111, Iran

(Received 12, revised 22 September 2007)

The Hosoya polynomial of a molecular graph G is defined as , where d(u,v) is the distance between vertices u and v. The first derivative of H(G,l) at l = 1 is equal to the Wiener index of G, defined as . The second derivative of at l = 1 is equal to the hyper-Wiener index, defined as . Xu et al. computed the Hosoya polynomial of zigzag open-ended nanotubes. Also Xu and Zhang computed the Hosoya polynomial of armchair open-ended nanotubes. In this paper, a new method was implemented to find the Hosoya polynomial of G = HC₆[p,q], the zigzag polyhex nanotori and to calculate the Wiener and hyper Wiener indices of G using H(G,l).

Keywords: Wiener index; hyper-Wiener index; Hosoya polynomial; nanotubes.

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J. Serb. Chem. Soc. 73 (3) 321–331 (2008)

UDC 54–36:541.183.1+547.639:543.4; JSCS–3714; doi: 10.2298/JSC0803321A; Original scientific paper

Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

RAMASAMY ANBARASAN, WANDUC LEE* and SEUNG SOON IM*

Department of Polymer Technology, Advanced Nanotechnology Research Laboratory, KAMaraj College of Engineering and Technology, Virudhunagar – 626 001, TAMil Nadu, India

*Department of Fiber and Polymer Engineering, Hanyang University, Seoul-133 791, South Korea

(Received 17 July 2007)

The inter-layer anion of layered double hydroxides (LDH) with a hydrotalcite (HT)-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH showed the highest increase of the basal spacing, which was confirmed by XRD analysis. FTIR results supported the interaction of the surfactants with the LDH. In addition, an increase in the thermal stability of the dodecanedioic acid intercalated HT was evidenced by the TGA method.

Keywords: hybrid; ion-exchange method; XRD; FTIR spectroscopy; TGA.

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J. Serb. Chem. Soc. 73 (3) 333–339 (2008)

UDC 546.719+66–914:541.183.1:546.33'131:66.049.2; JSCS–3715; doi: 10.2298/JSC0803333L; Original scientific paper

Concentration of rhenium from dilute sodium chloride solutions

DRAGOLJUB M. LUKIC, JURIJ L. VUCINA and SLOBODAN K. MILONJIC*

Laboratory for Radioisotopes, Vinca Institute of Nuclear Sciences, 11001 Belgrade, P. O. Box 522, Serbia

*Chemical DynAMics Laboratory, Vinca Institute of Nuclear Sciences, 11001 Belgrade, P. O. Box 522, Serbia

(Received 24 May 2007)

The conditions for the desorption of rhenium from the anion exchange resin Dowex 1-x8 by HNO₃, HCl, H₂SO₄ and NaOH were determined. The solution (5.0´10^-3 mol dm^-3 Re in 0.15 mol dm^-3 NaCl) was passed through a column containing 0.10 g of the resin. The total sorbed AMount of rhenium was 0.20 g/g of the resin. It was then eluted by the corresponding eluent in the concentration range up to about 3.0 mol dm^-3. The highest elution efficiency and the most favourable elution profile were found with 3.0 mol dm^-3 HNO₃. Over 77 % of the sorbed rhenium was found in the first 5 ml of the eluate. Practically all the rhenium was recovered with 20 ml of the acid. Under the given experimental conditions, HCl and H₂SO₄ were less favourable while NaOH was not applicable, due to very low efficiency of rhenium elution.

Keywords: ion exchange; concentration; rhenium; elution efficiency; elution profile.

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J. Serb. Chem. Soc. 73 (3) 341–350 (2008)

UDC 546.482+66.061:541.12.012–032.2:549.451.1:547.441–036.7; JSCS–3716, doi: 10.2298/JSC0803341B; Original scientific paper

Cd(II) extraction in PEG (1550)–(NH₄)₂SO₄ aqueous two-phase systems using halide extractants

LAURA BULGARIU and DUMITRU BULGARIU*

Department of Environmental Engineering and Management, Faculty of Chemical Engineering, Technical University “Gh. Asachi”, D. Mangeron 71A, 700050 Iaşi, Romania

*Department of Geology – Geochemistry, Faculty of Geography and Geology, “Al. I. Cuza” University, Carol I 20A, 700050 Iaşi, Romania

(Received 30 May, revised 30 August 2007)

The extraction of Cd(II) was studied in an aqueous PEG–(NH₄)₂SO₄ two-phase system, formed from a water-soluble polymer (poly(ethylene glycol), PEG) and an inorganic salt ((NH₄)₂SO₄), in the presence of halide ions. In the absence of a suitable extracting agent, Cd(II) remains predominantly in the salt-rich phase of the extraction system. By addition of halide ions as extractants, Cd(II) is extracted into the PEG-rich phase due to the formation of cadmium halide species. The efficiency of the extractants increased in the order: Cl^– < Br^– < I^–. From the distribution coefficients determined as a function of the concentration of the halide ions, the compositions of the extracted species were assumed and the “conditional” extractions constants calculated. The experimental results indicate that the extractability of Cd(II) in such extraction systems depends on the type of Cd(II) halide species (which is mainly determined by the acidity of salt stock solution) and of their stability.

Keywords: aqueous two-phase system; Cd(II) extraction; halide ions; poly(ethylene glycol); (NH₄)₂SO₄.

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J. Serb. Chem. Soc. 73 (3) 351–367 (2008)

UDC 621.315.59.004.12:541.135.5–0.34.293:546.33–36+544.3; JSCS–3717; doi: 10.2298/JSC0803351J; Original scientific paper

Semiconducting properties of oxide films formed onto an Nb electrode in NaOH solutions

VLADIMIR D. JOVIC and BORKA M. JOVIC

Institute for Multidisciplinary Research, 11030 Belgrade, P. O. Box 33, Serbia

(Received 26 June, revised 27 August 2007)

In this paper, the results of the potentiostatic formation of homogeneous and heterogeneous, nano-crystalline passive films of Nb₂O₅ onto an Nb electrode in NaOH solutions of different concentrations at potentials lower than 3.0 V vs. SCE are presented. The semiconducting properties of such films were investigated by EIS measurements. After fitting the EIS results by appropriate equivalent circuits, the space charge capacitance (C_sc) and space charge resistance (R_sc) of these films were determined. The donor density (N_sc), flat band potential (E_fb) and thickness of the space charge layer (d_sc) for such oxide films were determined from the corresponding Mott–Schottky (M–S) plots. It is shown that all oxide films were n-type semiconductors in a certain potential range.

Keywords: nano-crystalline; Nb₂O₅; passive film; Mott–Schottky plot; n-type semiconductor.

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J. Serb. Chem. Soc. 73 (3) 369–376 (2008)

UDC 546.815'711'24:546.815'24'22:534:543.42–74; JSCS–3718; doi: 10.2298/JSC0803369T; Original scientific paper

Plasmon – two phonon interaction in PbMnTe and PbTeS alloys

JELENA TRAJIC, NEBOJSA ROMCEVIC, MAJA ROMCEVIC and VLADIMIR N. NIKIFOROV*

Institute of Physics, Department for Solid State Physics and New Materials, P. O. Box 68, 11001 Belgrade, Serbia

*Department of Low-Temperature Physics, Moscow State University, Moscow, Russia

(Received 18 December 2006)

In this work far-infrared spectroscopy over a wide temperature range was used to investigate the vibration properties of Pb_1‑xMn_xTe (x £ 0.12) and PbTe_1-xS_x (x £ 0.05) single crystals. In the analysis of the experimental results, a dielectric function which in advance takes into account the existence of plasmon – two phonon interaction was employed. As a result of the best fit, the three frequencies of the coupled modes were obtained and then the values for the two LO modes and the plasma frequency (wP) were calculated. It was found that the phonons in PbTe_1-xS_x and Pb_1-xMn_xTe showed two-mode behavior (each TO–LO mode pair for the end members degenerates to an impurity mode).

Keywords: semimagnetic semiconductors; far-infrared spectroscopy; vibration properties; phonon behavior.

Full Article - PDF 321 KB

J. Serb. Chem. Soc. 73 (3) 377–384 (2008)

UDC 546.682’86’815:544.344+544.015.3:536.7; JSCS–3719; doi: 10.2298/JSC0803377M; Original scientific paper

Prediction of phase equilibria in the In–Sb–Pb system

DUSKO MINIC, DRAGAN MANASIJEVIC*, DRAGANA ZIVKOVIC*, NADA STRBAC* and ZVONIMIR STANKOVIC*

University of Priština, Mining and Metallurgy Faculty, 38220 Kosovska Mitrovica, Serbia

*University of Belgrade, Technical Faculty, VJ 12, 19210 Bor, Serbia

(Received 30 June 2007)

Binary thermodynAMic data, successfully used for phase diagrAM calculations of the binary systems In–Sb, Pb–Sb and In–Pb, were used for the prediction of the phase equilibria in the ternary In–Sb–Pb system. The predicted equilibrium phase diagrAM of the vertical Pb–InSb section was compared with the results of differential thermal analysis DTA and optical microscopy. The calculated phase diagrAM of the isothermal section at 300 °C was compared with the experimentally (SEM, EDX) determined composition of phases in the chosen alloys after annealing. Very good agreement between the binary-based thermodynAMic prediction and the experimental data was found in all cases. The calculated liquidus projection of the ternary In–Sb–Pb system is also presented.

Keywords: In–Sb–Pb system; phase diagrAM; thermodynAMics.

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