JSCS - Vol 72, No 11

JSCS Vol 72, No. 11

Whole issue - PDF (2.575 KB)

J. Serb. Chem. Soc. 72 (11) 1039–1044 (2007)

UDC 547.633.6+547.484:542.913, JSCS–3637, doi: 10.2298/JSC0711039P; Original scientific paper

Synthesis and characterization of heterocyclic substituted fluoran compounds

SACHIN V. PATEL, MANISH P. PATEL and RANJAN G. PATEL

Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar–388 120, Gujarat, India

(Received 5 September 2005, revised 1 February 2006)

New quinazolinone-substituted fluoran compounds were synthesized by reaction of keto acid, 2’-carboxy-2-hydroxy-4-N-pyrrolidinylbenzophenone with different quinazolinone derivatives in the presence of conc. sulphuric acid. All the synthesized fluoran compounds were characterized by spectroscopic methods (IR, ¹H-NMR and UV–visible spectroscopy) and elemental analysis. The fluoran compounds are colourless or nearly colourless and develop colour on contact with electron-accepting compounds.

Keywords: fluoran, keto acid, synthesis, quinazolinone.

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J. Serb. Chem. Soc. 72 (11) 1045–1051 (2007)

UDC *Cotinus coggygria:665.52/.54+615.281/.282(497.11), JSCS–3638, doi: 10.2298/JSC0711045N; Original scientific paper

Chemical composition, antibacterial and antifungal activity of the essential oils of Cotinus coggygria from Serbia

MIROSLAV NOVAKOVIC, IVAN VUCKOVIC, PEDJA JANACKOVIC*, MARINA SOKOVIC**, ANKA FILIPOVIC***, VELE TESEVIC**** and SLOBODAN MILOSAVLJEVIC****

Institute of Chemistry, Technology and Metallurgy, Njegoseva 12, 11000 Belgrade, Serbia

*Faculty of Biology, Studentski trg 16, 11001 Belgrade, Serbia

**Institute for Biological Research “Sinisa Stankovic”, Bulevar Despota Stefana 142, 11000 Belgrade, Serbia

***Institute of Public Health, Bulevar Despota Stefana 54a, 11000 Belgrade

****Faculty of Chemistry, Studentski trg 16, 11001 Belgrade, Serbia

(Received 19 December 2006, revised 6 July 2007)

Essential oils from leaves with young branches of Cotinus coggygria Scop. from two localities in Serbia (Deliblatska pescara and Zemun), obtained by hydrodistillation, were analysed by GC–MS. Thirty-one component were identified from both oils and AMong them monoterpenic hydrocarbons were the dominant class (87.4 and 93.1 %). The dominant constituent in both essential oils was limonene (47.0 and 39.2 %). Both oils were also tested for antibacterial and antifungal activities. In comparison to streptomycin, both oils showed slightly higher activity (against most GrAM-positive bacteria) in the disc diffusion method and slightly lower activity when the microdilution method was employed. They also exhibited antifungal potential higher than that of the commercial fungicide bifonazole.

Keywords: Cotinus coggygria, essential oil composition, antibacterial activity, antifungal potential.

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J. Serb. Chem. Soc. 72 (11) 1053–1062 (2007)

UDC 546.56’47+547.979.7:535.371:581.171, JSCS–3639, 10.2298/JSC0711053Z; Original scientific paper

Different possibilities for the formation of complexes of copper and zinc with chlorophyll inside photosynthetic organelles: chloroplasts and thylakoids

JELENA ZVEZDANOVIC, DEJAN MARKOVIC and GORAN NIKOLIC

Faculty of Technology, 16000 Leskovac, Serbia

(Received 8 September 2006, revised 21 March 2007)

The possibility of the formation of copper and zinc complexes with chlorophyll in photosynthetic organelles (chloroplasts) and suborganelles (thylakoids) was studied. The visible and fluorescence spectra obtained from chloroplasts and thylakoids in the presence of the two metals confirmed complex formation in the case of copper, while such possibility appears to be very minor in the case of zinc. The

reason for this distinction lies in the different type of complexes which chlorophyll forms with the two metals: only “central” or “substitution” copper–chlorophyll complexes may be formed inside the two isolated entities, while the formation of a possible zinc–chlorophyll “peripheral” type of complex is prevented for steric reasons. The latter fact is of high biological relevance, since both complexes may cause an irreversible impairment and dAMage of photosynthetic function.

Keywords: chlorophyll, copper, zinc, fluorescence, chloroplasts, thylakoids.

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J. Serb. Chem. Soc. 72 (11) 1063–1067 (2007)

UDC 547.77+519.85:548.1.023, JSCS–3640, doi: 10.2298/JSC0711063Y; Original scientific paper

Computing PI and Szeged indices of multiple phenylenes and cyclic hexagonal–square chain consisting of mutually isomorphic hexagonal chains

H. YOUSEFI–AZARI, J. YAZDANI, A. BAHRAMI and A. R. ASHRAFI*

School of Mathematics, Statistics and Computer Science, University of Tehran, Tehran, Iran

*Department of Mathematics, Faculty of Science,University of Kashan, Kashan 87317–51167, Iran

(Received 28 June, revised 19 December 2006)

PI and Szeged indices are two of the most important topological indices defined in chemistry. In this study, the PI and Szeged indices of linear [n]-phenylenes and a cyclic hexagonal-square chain consisting of n mutually isomorphic hexagonal chains were computed. The PI and Szeged indices of a multiple phenylene, which is the 2-dimensional case of a phenylenic nanotube and nanotorus, were determined.

Keywords: PI index, Szeged index, linear [n]-phenylenes, multiple phenylenes nanotube.

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J. Serb. Chem. Soc. 72 (11) 1069–1074 (2007)

UDC 546.713’723’763.004.10:54–71–034:542.913, JSCS–3641, doi: 10.2298/JSC0711069S; Original scientific paper

Trivalent metal ion directed synthesis and characterization of macrocyclic complexes

DHARAM PAL SINGH and RAMESH KUMAR

Department of Chemistry, National Institute of Technology, Kurukshetra-136 119, India

(Received 22 January, revised 15 June 2007)

A novel series of complexes of the type [M(TML)X]X₂, where TML is a tetradentate macrocyclic ligand, M = Cr(III), Mn(III) or Fe(III), X = Cl^–, CH₃COO^– or NO₃^-, were synthesized by template condensation of dibenzoyl and thiocarbohydrazide in the presence of trivalent metal salts in a methanolic medium. The complexes were characterized with the help of elemental analyses, conductance measurements, molecular weight determination, magnetic measurements, electronic, NMR, infrared and far infrared spectral studies. The electronic spectra together with the magnetic moments suggest five coordinate square pyrAMidal geometry for these complexes. The molar conductance indicates them to be 1:2 electrolytes.

Keywords: macrocyclic complexes, dibenzoyl, trivalent metal salts, thiocarbohydrazide, template synthesis.

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J. Serb. Chem. Soc. 72 (11) 1075–1084 (2007)

UDC 546.742’562’472:542.9+547.571+547.551:543.422.25, JSCS–3642, doi: 10.2298/JSC0711075K; Original scientific paper

Metal complexes of Schiff’s bases derived from 3-(arylazo)-2,4-pentanediones with 2-AMinophenol and 2-AMinothiophenol

K. KRISHNANKUTTY, P. SAYUDEVI* and MUHAMMED BASHEER UMMATHUR**

Department of Chemistry, University of Calicut, Kerala–673635, India

*Department of Chemistry, NSS College, Manjeri, Kerala–676122, India

**Department of Chemistry, Unity Women’s College, Manjeri, Kerala–676122, India

(Received 8 February 2007)

Phenylazo- and thiazolylazo-2,4-pentanediones on reaction with 2-AMinophenol and 2-AMinothiophenol yielded a new series of polydentate Schiff’s base ligands. The structure and tautomeric nature of these compounds and their metal complexes were established on the basis of their IR, ¹H-NMR and mass spectral data. The spectral and analytical data revealed the condensation of both carbonyl groups of 3-(2-thiazolylazo)- 2,4-pentanedione with 2-AMinophenol to form an N₂O₂ tetradentate ligand. Details on the formation of its [ML] complexes with Ni(II), Cu(II) and Zn(II) and the nature of their bonding are discussed based on analytical, IR, ¹H-NMR and mass spectral data.

Keywords: 3-(arylazo)-2,4-pentanediones, Schiff’s bases, metal complexes, IR spectra, 1H-NMR spectra, mass spectra.

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J. Serb. Chem. Soc. 72 (11) 1085–1094 (2007)

UDC 547.835+547.963.32:543.552, JSCS– 3643, doi: 10.2298/JSC0711085S; Original scientific paper

Linear sweep polarographic determination of nucleic acids using acridine orange as a bioprobe

WEI SUN, NA ZHAO, XIANLONG YUAN and KUI JIAO

College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, P. R. China

(Received 7 November 2006, revised 2 April 2007)

The interaction of acridine orange (AO) with double-stranded (ds) DNA in aqueous solution was investigated by linear sweep polarography (LSP) on a dropping mercury working electrode (DME). In pH 2.5 Britton–Robinson (B–R) buffer solution, AO had a sensitive linear sweep polarographic reductive peak at –0.89 V (vs. SCE), which could be greatly inhibited by the addition of dsDNA, with a positive shift of the peak potential. Based on the decrease of the reductive peak current, a new quantitative electrochemical determination method for dsDNA was developed with a linear range of 2.0−20.0 mg l^-1 and the linear regression equation: ΔIp” (nA) = 111.90 C (mg l^-1)+125.32 (n = 9, γ = 0.997). The influences of commonly co-existing substances, such as metal ions, AMino acid, etc., on the determination were also investigated. The method is sensitive, rapid and simple with good selectivity. The new proposed method was further applied to the detection of RNA and three synthetic sAMples containing dsDNA with satisfactory results. The binding number and the equilibrium constant between dsDNA and AO were calculated by an electrochemical method.

Keywords: acridine orange, nucleic acids, linear sweep polarography, electroanalysis.

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J. Serb. Chem. Soc. 72 (11) 1095–1101 (2007)

UDC 546.92’96+547.261+546.33–36:541.138.2, JSCS– 3644, doi: 10.2298/JSC0711095T; Short communication

Kinetic study of methanol oxidation on Pt₂Ru₃/C catalyst in the alkaline media

A. V. TRIPKOVIC, K. DJ. POPOVIC and J. D. LOVIC

ICTM – Institute of Electrochemistry, University of Belgrade, Njegoseva 12, P.O. Box 473, 11000 Belgrade, Serbia

(Received 20 June, revised 6 August 2007)

The electrochemical oxidation of methanol in NaOH solution was exAMined on a thin film Pt₂Ru₃/C electrode. The XRD pattern revealed that the Pt₂Ru₃ alloy consisted of a solid solution of Ru in Pt and a small AMount of Ru or a solid solution of Pt in Ru. It was shown that in alkaline solution, the difference in activity between Pt/C and Pt₂Ru₃/C is significantly smaller than in acid solution. It is proposed that the reaction follows a quasi bifunctional mechanism. The kinetic parAMeters indicated that the chemical reaction between adsorbed CO_ad and OH_ad species could be the rate limiting step.

Keywords: platinum–ruthenium alloy, supported nanocatalyst; XRD analysis, methanol oxidation, alkaline solution.

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J. Serb. Chem. Soc. 72 (11) 1103–1113 (2007)

UDC 66.021.3:62–218+54–138:54–72, JSCS– 3645, 10.2298/JSC0711103B; Original scientific paper

Wall-to-liquid mass transfer in fluidized beds and vertical transport of inert particles

NEVENKA BOSKOVIC–VRAGOLOVIC, RADMILA GARIC–GRULOVIC* and ZELJKO GRBAVCIC

Faculty of Technology and Metallurgy, Department of Chemical Engineering, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia

*Institute for Chemistry, Technology and Metallurgy, Njegoseva 12 11000 Belgrade, Serbia

(Received 20 June, revised 6 August 2007)

Keywords: platinum–ruthenium alloy, supported nanocatalyst; XRD analysis, methanol oxidation, alkaline solution.

Full Article - PDF 335 KB

J. Serb. Chem. Soc. 72 (11) 1115–1125 (2007)

UDC 546.56+661.183.8:620.1:536.421.5, JSCS–3646, 10.2298/JSC0711115K; Original scientific paper

Sintering of Cu–Al₂O₃ nano-composite powders produced by a thermochemical route

MARIJA KORAC, ZORAN ANDJIC*, MILOS TASIC* and ZELJKO KAMBEROVIC

Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade, Serbia

*The Scientific Research Center, Nikole Pasica 26, 31000 Uzice, Serbia

(Received 25 April 2006)

This paper presents the synthesis of nano-composite Cu–Al₂O₃ powder by a thermochemical method and sintering, with a comparative analysis of the mechanical and electrical properties of the obtained solid sAMples. Nano-crystalline Cu–Al₂O₃ powders were produced by a thermochemical method through the following stages: spray-drying, oxidation of the precursor powder, reduction by hydrogen and homogenization. Characterization of powders included analytical electron microscopy (AEM) coupled with energy dispersive spectroscopy (EDS), differenttial thermal and thermogravimetric (DTA–TGA) analysis and X-ray diffraction (XRD) analysis. The size of the produced powders was 20–50 nm, with a noticeable presence of agglomerates. The composite powders were characterized by a homogenous distribution of Al₂O₃ in a copper matrix. The powders were cold pressed at a pressure of 500 MPa and sintered in a hydrogen atmosphere under isothermal conditions in the temperature range from 800 to 900 °C for up to 120 min. Characterization of the Cu–Al₂O₃ sintered system included determination of the density, relative volume change, electrical and mechanical properties, exAMination of the microstructure by SEM and focused ion beAM (FIB) analysis, as well as by EDS. The obtained nano-composite, the structure of which was, with certain changes, presserved in the final structure, provided a sintered material with a homogenеous distribution of dispersoid in a copper matrix, with exceptional effects of reinforcement and an excellent combination of mechanical and electrical properties.

Keywords: copper, alumina, powder, nano-composite, sintering.

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J. Serb. Chem. Soc. 72 (11) 1127–1138 (2007)

UDC 546.284–31.002.2:539.22:666.293.35, JSCS–3647, 10.2298/JSC0711127J; Original scientific paper

Fabrication of SiO₂-based microcantilevers by anisotropic chemical etching of (100) single crystal Si

VESNA JOVIC, JELENA LAMOVEC, MIRJANA POPOVIC and ZARKO LAZIC

Institute of Chemistry, Technology and Metallurgy – Center for microelectronic technologies and single crystals, Njegoseva 12, Belgrade, Serbia

(Received 19 July 2006)

The undercutting process of thermal SiO₂ microcantilevers with different orientations on (100) Si wafer was studied. The silicon substrate was removed by anisotropic chemical etching with a 25 wt. % aqueous solution of TMAH or a 30 wt. % aqueous KOH solution at 80 °C. It was found that <110> oriented cantilevers were undercutting frontally along the length and <100> oriented cantilevers experience undercutting along the width of the cantilever, which is a less time consuming process. The studies showed that the <100> orientation of SiO₂ microbridges enables theirs fabrication on a (100) oriented Si substrate.

Keywords: anisotropic wet chemical etching, TMAH, KOH, SiO₂ microcantilever, SiO₂ microbridge, (100) oriented Si substrate.

Full Article - PDF 309 KB

J. Serb. Chem. Soc. 72 (11) 1139–1153 (2007)

UDC 531.3:547.391.1+541.182.41, JSCS–3648, 10.2298/JSC0711139K; Original scientific paper

Comparison of the swelling kinetics of a partially neutralized poly(acrylic acid) hydrogel in distilled water and physiological solution

ALEKSANDAR KOSTIC, BORIVOJ ADNADJEVIC*, ALEKSANDAR POPOVIC** and JELENA JOVANOVIC**

Faculty of Agriculture, Nemanjina 6, 11080 Zemun, Belgrade, Serbia

*Faculty of Physical Chemistry, Studentski trg 16, 11000 Belgrade, Serbia

**Faculty of Chemistry, Studentski trg 12–16, 11000 Belgrade, Serbia

(Received 23 February 2006, revised 19 February 2007)

The isothermal kinetics curves of the swelling of a poly(acrylic acid) hydrogel in distilled water and physiological solution at temperatures ranging from 20 to 40 ºC were determined. The possibility of applying both the Fick’s kinetics model and kinetics model of the first order chemical reaction to the swelling kinetics of the PAA hydrogel in distilled water and physiological solution were exAMined. It was found that the possibilities of applying these models were limited. The new model of the kinetics of swelling in distilled water and physiological solution was established. The kinetic parAMeters (E_a, lnA) for the swelling in distilled water and physiological solution were determined. The decrease of the equilibrium degree of swelling and the saturation swelling rate of the swelling of the PAA hydrogel in physiological solution compared to swelling in distilled water could be explained by the decreased differences in the ionic osmotic pressures between the hydrogel and the swelling medium. The increase of the initial swelling rate in the physiological solution might be caused by an increased density of charges at the network and by an increased affinity of the network towards the water molecules. The increase of the activation energy of the swelling of the PAA hydrogel in the physiological solution is a consequence of its additional “ionic crosslinking”.

Keywords: swelling kinetics, kinetics parAMeters, model, poly(acrylic acid) hydrogel.

Full Article - PDF 367 KB

J. Serb. Chem. Soc. 72 (11) 1155–1169 (2007)

UDC 547.313.2+546.76–31+66.095.26, JSCS–3649, doi: 10.2298/JSC0711155S; Original scientific paper

The charge percolation mechanism and simulation of Ziegler–Natta polymerizations.

Part VI. Mechanism of ethylene polymerization by supported chromium oxide

DRAGOSLAV STOILJKOVIC, BRANKA PILIC, MISA BULAJIC*, NEBOJSA DJURASOVIC* and NIKOLAJ OSTROVSKI**

Faculty of Technology, University of Novi Sad, Bul. Cara Lazara 1, 21000 Novi Sad, Serbia

*HIP-Petrohemija, 26000 Pančevo, Serbia

**HIPOL, 25250 Odžaci, Serbia

(Received 27 October 2006, revised 13 June 2007)

Despite intensive research over the last 50 years, many questions concerning ethylene polymerization by supported chromium oxide are still unanswered. Hence, the very fundAMental issues of this polymerization are discussed in this paper. It is shown that a charge percolation mechanism (CPM) of olefin polymerization by Ziegler–Natta transition metal complexes, recently proposed by us, can give the answers in this case, too.

Keywords: Ethylene polymerization, Phillips CrOx/SiO₂, charge percolation mechanism.

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