J. Serb. Chem. Soc. 74 (5) 477–491 (2009)
UDC 539.196+547.43:541.123.21:531.732; JSCS–3848; doi: 10.2298/JSC0905477D; Authors’ review

Molecular interaction studies of the volumetric behaviour of binary liquid mixtures containing alcohols
BOJAN D. DJORDJEVIĆ, IVONA R. RADOVIĆ, MIRJANA LJ. KIJEVČANIN, ALEKSANDAR Ž. TASIĆ and SLOBODAN P. ŠERBANOVIĆ
Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P.O. Box 35-03, 11120 Belgrade, Serbia

(Received 13 January 2009)

An attempt has been made to relate the volumetric effects involved in the binary mixtures of normal and branched alcohols and various components (aromatics, halo and nitroaromatics and haloaliphatics) with the molecular interactions of unlike molecules. This review is a condensation of research activities developed in recent years as results of a better understanding of volumetric behaviour and a stronger insight into the complex structure of those mixtures. The influence of important contributions of a physical, chemical and geometrical nature that change excess molar volume, V^E (positive, sigmoidal, negative) is considered and explained in detail. It appears that the balance between these contributions is quite sensitive to the behaviour of the alcohol molecules in contact with the chosen compounds.

Keywords: molecular interactions; volumetric properties; excess volume; alcohols; binary liquid mixtures.

J. Serb. Chem. Soc. 74 (5) 493–502 (2009)
UDC 66.094.3+544.4:547.564.3:546.175–4; JSCS–3849; doi: 10.2298/JSC0905493M; Original scientific paper

A mechanistic investigation of the oxidation of N,a-diphenylnitrones by dichlorAMine-T in aqueous acetonitrile medium – a non-linear HAMmett plot
SUBRAMANIAN MANIVARMAN, GOVINDASAMY RAJARAJAN, GOVINDASAMY MANIKANDAN, MAHALIGAM SEKAR*, JAYARAMAN JAYABHARATHI and VENUGOPAL THANIKACHALAM
Department of Chemistry, AnnAMalai University, AnnAMalainagar 608 002, TAMil Nadu, India

*Department of Chemistry, Post Graduate Centre, Government Arts and Science College, ChidAMbarAM 608 001, India

(Received 24 May 2007, revised 9 February 2009)

The kinetics of oxidation of a number of meta- and para-substituted N,a-diphenylnitrones (nitrone) by dichlorAMine-T (DCT) was investigated in the presence of alkali in aqueous acetonitrile medium. The order with respect to DCT was one and to OH^- an inverse fractional order. The reaction was first order with respect to nitrone. Both electron releasing and withdrawing substituents suppress the reaction rate. The observed rate constant for the substituents were plotted against the HAMmett constant, s, and a non-linear concave downward curve was obtained. The electron withdrawing substituents fall on one side of the curve, having a negative r value and the electron releasing substituents fall on the other side, with a positive r value. A mechanism is proposed and the derived rate law is in conformity with the observed results.

Keywords: nitrones; kinetics; dichlorAMine-T; non-linear concave downward curve.

J. Serb. Chem. Soc. 74 (5) 503–511 (2009)
UDC 546.172.6+66.097.8+546.62’13:599.323.4:591.481.1; JSCS–3850; doi: 10.2298/JSC0905503S;  Original scientific paper

Effects of various nitric oxide synthase inhibitors on AlCl₃-induced neuronal injury in rats
IVANA STEVANOVIĆ, MARINA JOVANOVIĆ, ANKICA JELENKOVIĆ*, MIODRAG ČOLIĆ and MILICA NINKOVIĆ

Military Medical Academy, Institute for Medical Research, Crnotravska 17, Belgrade, Serbia

*Institute for Biological Research, Belgrade, Serbia

(Received 1 October, revised 9 December 2008)

The present study was aimed at determining the effectiveness of nitric oxide synthase (NOS) inhibitors: N-nitro-L-arginine methyl ester, 7-nitroindazole and AMinoguanidine in modulating the toxicity of AlCl₃ on superoxide production and the malondialdehyde concentration of Wistar rats. The animals were sacrificed 10 min and 3 days after the treatment and the forebrain cortex was removed. The results show that AlCl₃ exposure promotes oxidative stress in different neural areas. The biochemical changes observed in the neuronal tissues show that aluminum acts as pro-oxidant, while NOS inhibitors exert an anti-oxidant action in AlCl3-treated animals.

Keywords: aluminum; forebrain cortex; NOS inhibitors; superoxide production; lipid peroxidation.

J. Serb. Chem. Soc. 74 (5) 513–522 (2009)
UDC 628.511.134+616.995.42:616.248:648.6:645.47; JSCS–3851; doi: 10.2298/JSC0905513M; Original scientific paper

Isolation and characterization of the 68 kD allergen from house dust mite Dermatophagoides pteronyssinus
KATARINA MILOVANOVIĆ, LIDIJA BURAZER, OLGA VUČKOVIĆ, MARINA ATANASKOVIĆ-MARKOVIĆ*, TANJA ĆIRKOVIĆ VELIČKOVIĆ**, RATKO M. JANKOV** and MARIJA GAVROVIĆ-JANKULOVIĆ**
Institute of Virology, Vaccines and Sera, Torlak, Belgrade, Serbia

*University Children’s Hospital, Medical Faculty, University of Belgrade, Serbia

**Biochemistry Department, Faculty of Chemistry, University of Belgrade, Belgrade, Serbia

(Received 4 November 2008, revised 6 February 2009)

House dust mites (HDM) represent a major source of allergens, contributing to the increasing incidence of type I hypersensitivity disease worldwide. Over 30 different IgE-binding proteins from the HDM extract were detected. Although group 1 and 2 have been identified as major allergens, due to the safety and efficacy of allergy diagnosis and immunotherapy, there is a need to carefully evaluate the clinical relevance of other allergens present in the HDM extract. In regard to this, a high molecular mass allergen of about 68 kD was purified from the HDM extract using a combination of gel permeation chromatography and reversed-phase chromatography. The IgG and IgE reactivity of the purified protein were preserved during the purification process, as confirmed by Western blot analysis with polyclonal rabbit antibodies and dot blot analysis with a pool of sera from subjects with house dust mite allergy, respectively. In addition, the IgE reactivity was confirmed using ELISA testing with nine patient sera. The biological potency of the 68 kD allergen was confirmed by skin prick testing in five allergic subjects, suggesting that the high molecular mass allergen is a good candidate for component-resolved diagnosis of house dust mite allergy and eventual therapeutic treatment.

Keywords: HDM; Dermatophagoides pteronyssinus; allergens; isolation.

J. Serb. Chem. Soc. 74 (5) 523–535 (2009)

J. Serb. Chem. Soc. 74 (5) 537–548 (2009)        

J. Serb. Chem. Soc. 74 (5) 549–554 (2009)

UDC 547.534+547.629:66.022.362+537.872; JSCS–3854; doi: 10.2298/JSC0905549D; Original scientific paper

J. Serb. Chem. Soc. 74 (5) 555–571 (2009)

UDC 547.564.4’77+547.821+547.46+547.828+547.586.71:535.338+535.513; JSCS–3855; doi: 10.2298/JSC0905555B; Original scientific paper

Theoretical and experimental investigations on the structure and vibrational spectra of 6-AMino-3-methyl-1-phenyl-1H-pyrazolo-[3,4-b]pyridine-5-carboxylic acid and 6,7-dihydro-3-methyl-6-oxo-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile

KHALED BAHGAT, NAZM AL-DEN JASEM* and TALAAT EL-EMARY**

Chemistry Department, Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez, Egypt

*Chemistry Department, Faculty of Sciences, Aleppo University, Syria

**Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt

(Received 22 October 2008, revised 12 February 2009)

The solid phase FT-IR and FT-RAMan spectra of 6-AMino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid (PYRPCA) and 6,7-dihydro-3-methyl-6-oxo-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile (PYRPCN) were recorded in the region 4000–400 cm^-1. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on the density functional theory (DFT) using standard B3LYP, BLYP and ab initio RHF methods with 6-31G^* basis set and were scaled using a recommended set of scaling factors yielding fairly good agreement between the observed and calculated frequencies. Based on the present good quality, the scaled quantum mechanical (SQM) force field, a reliable description of the fundAMentals of PYRPCA and PYRPCN, was provided. The calculations predicated a predominance of different tautomers in PYRPCA and keto-enol tautomers in PYRPCN. For PYRPCA, the most stable conformer is stabilized by intrAMolecular hydrogen bonding. The characteristic of the hydrogen bonding is its strengthening effect on the conjugation of the NH2 and COOH groups with the pyridine ring.

Keywords: DFT calculations; vibrational spectra; 6-AMino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid; 6,7-dihydro-3-methyl-6-oxo-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile.

J. Serb. Chem. Soc. 74 (5) 573–579 (2009)        

UDC 632.951+541.135.5–0.34.21:544.6.004.12; JSCS–3856, doi: 10.2298/JSC0905573T; Original scientific paper

A study of the electrochemical behaviour of methomyl on a gold electrode in a neutral electrolyte

ANDJELKA V. TOMAŠEVIĆ, MILKA L. AVRAMOV IVIĆ*, SLOBODAN D. PETROVIĆ**^,***, MIĆA B. JOVANOVIĆ** and DUŠAN Ž. MIJIN**

Center for Pesticides and Environment Protection, Banatska 31b, Belgrade-Zemun, Serbia

*ICTM – Institute of Electrochemistry, University of Belgrade, Njegoševa 12, Belgrade, Serbia

**Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade, Serbia

***Hemofarm, Pharmaceutical and Chemical Industry, Vršac, Serbia

(Received 9 December 2008, revised 16 January 2009)

A gold electrode was used for the qualitative and quantitative electrochemical determination of analytical methomyl in a neutral electrolyte (0.050 M NaHCO₃) using cyclic linear sweep voltAMmetry. In the potential range from –800 mV vs. SCE to 1000 mV vs. SCE the analytical methomyl was quantitatively determined in the concentration range 4.0–16 mg L^-1. In the potential range from ‑1300 mV vs. SCE to 1300 mV vs. SCE, methomyl was qualitatively determined by two anodic and four cathodic reactions. Cycling the potential in this range for 150 min caused the degradation of the molecule, which was confirmed by HPLC analysis. On the other hand, technical methomyl exhibited an inhibition of the gold electrode surface due to the impurities.

Keywords: insecticide; methomyl; gold electrode; cyclic voltAMmetry.

J. Serb. Chem. Soc. 74 (5) 581–593 (2009)

UDC 547.475.2+546.73–36+66.087.3+541.135.5–039.26; JSCS–3857; doi: 10.2298/JSC0905581K; Original scientific paper

Electro-oxidation of ascorbic acid catalyzed on cobalt hydroxide-modified glassy carbon electrode

GHASEM KARIM-NEZHAD, MOHAMMAD HASANZADEH, LOTFALI SAGHATFOROUSH, NASRIN SHADJOU, BALAL KHALILZADEH* and SOHRAB ERSHAD**

Department of Chemistry, Faculty of Science, PayAMe Noor University, P.O. Box 58168-45164, Khoy, Iran

*Department of Chemistry, Faculty of Science, Arak University, Arak, Iran

**Department of Chemistry, Faculty of Science, PayAMe Noor University, Marand, Iran

(Received 15 July, revised 8 December 2008)

The electrochemical behavior of ascorbic acid on a cobalt hydroxide modified glassy carbon (CHM–GC) electrode in alkaline solution was investigated. The process of the involved oxidation and its kinetics were established using the cyclic voltAMmetry, chronoAMperometry techniques, as well as by steady state polarization measurements. The results revealed that cobalt hydroxide promotes the rate of oxidation by increasing the peak current; hence ascorbic acid is oxidized at lower potentials, which is thermodynAMically more favorable. The cyclic voltAMmogrAMs and chronoAMperometry indicate a catalytic EC mechanism is operative with the electrogeneration of Co(IV) as the electrochemical process. Also, the process is diffusion-controlled and the current–time responses follow Cottrellian behavior. This result was confirmed by steady state measurements. The rate constants of the catalytic oxidation of ascorbic acid and the electron-transfer coefficient are reported.

Keywords: ascorbic acid; electrocatalysis; modified electrode; alkaline media; cyclic voltAMmetry; chronoAMperometry.

J. Serb. Chem. Soc. 74 (5) 595–605 (2009)

UDC 539.121.62:546.62’56:66.014; JSCS–3858; doi: 10.2298/JSC0905595R; Original scientific paper

Characteristics of Cu–Al₂O₃ composites of various starting particle size obtained by high-energy milling

VIŠESLAVA RAJKOVIĆ, DUŠAN BOŽIĆ and MILAN T. JOVANOVIĆ

Institute of Nuclear Sciences “Vinča”, P.O. Box 522, 11001 Belgrade, Serbia

(Received 9 December 2008)

The powder Cu– Al₂O₃ composites were produced by high-energy milling. Various combinations of particle size and mixtures and approximately constant AMount of Al₂O₃ were used as the starting materials. These powders were separately milled in air for up to 20 h in a planetary ball mill. The copper matrix was reinforced by internal oxidation and mechanical alloying. During the milling, internal oxidation of pre-alloyed Cu-2 mass %-Al powder generated 3.7 mass % Al₂O₃ nano-sized particles finely dispersed in the copper matrix. The effect of different size of the starting copper and Al2O3 powder particles on the lattice parAMeter, lattice distortion and grain size, as well as on the size, morphology and microstructure of the Cu– Al₂O₃ composite powder particles was studied.

Keywords: Cu–Al₂O₃ composite powders; high-energy milling; size of the starting powder particles.

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