JSCS Vol 73, No. 2

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J. Serb. Chem. Soc. 73 (2) 131–138 (2008)
UDC 547.78+542.913:547.334:547.77; JSCS–3695; doi: 10.2298/JSC0802131K;  Original scientific paper

Expeditious synthesis of 1,3,4-oxadiazole derivatives via sydnones
RAVINDRA R. KAMBLE, B. S. SUDHA and D. G. BHADREGOWDA

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

 

(Received 21 June, revised 1 August 2007)

The clean cyclization of chalcones (1a–c/2a–c) with hydrazine hydrate under microwave irradiation afforded pyrazolines derivatised with sydnone (3d–i/4d–i), which underwent 1,3-dipolar cyclo-addition with acetic anhydride to form pyrazolines appended with 1,3,4-oxadiazoles (5g–l/6g–l). The newly synthesized compounds were confirmed by spectral and elemental analyses. In comparison to classical heating, the results indicate that microwave irradiation affords higher yields, shorter reaction times (4–12 min) and cleaner reactions.

 

Keywords: porphyrin microwave irradiation; sydnones; chalcones; pyrazolines; 1,3,4-oxadiazoles.

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J. Serb. Chem. Soc. 73 (2) 139–145 (2008)
UDC 662.237.3:66–95:579.23:579.67; JSCS–3696; doi: 10.2298/JSC0802139S; Original scientific paper

Recombinant expression of monovalent and bivalent anti-TNT-antibodies – evaluation of different expression systems
MLADEN SIMONOVIC, SVETLANA ZLATANOVIC-MILOSEVIC*, MIROSLAV M. VRVIC** and BRANISLAV SIMONOVIC
Institute for General and Physical Chemistry, Studentski trg 12–16, 11000 Belgrade, Serbia

*Faculty of Mathematics and Natural Sciences, University of Kragujevac, Radoja Domanovica 12, 34000 Kragujevac, Serbia

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


(Received 7 February, revised 2 July 2007)

Monoclonal 11B3 anti-TNT (trinitrotoluene) antibody was expressed as a monovalent and bivalent form using different prokaryotic and eukaryotic expression systems. Recombinant expression in Escherichia coli, mammalian cells and the methylotrophic yeast Pichia pastoris was performed to obtain disulfide-linked and glycosylated antibody forms. The generation of antibody and subsequent evaluation of the expression rates were performed using intracellular, excretory and periplasmatic expression techniques. All methods involved striving for native expressed antibody with maintenance of its functionality only.

 

Keywords: TNT; antibody; recombinant expression; 11B3; scFv.

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J. Serb. Chem. Soc. 73 (2) 147–156 (2008)
UDC 66.011+665.75.000.57.002.2:577.15; JSCS–3697; doi: 10.2298/JSC0802147O;  Original scientific paper

Optimization of the production of biodiesel by a commercial immobilized lipase in a solvent-free system using a response surface methodology
NEVENA OGNJANOVIC, DEJAN BEZBRADICA and ZORICA KNEZEVIC
Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade, Serbia

(Received 14 March, revised 2 July 2007)

Response surface methodology was used for the evaluation of the effects of various factors on the synthesis of biodiesel catalyzed with immobilized lipase from Rhizomucor miehei in a solvent-free system. The production of biodiesel was optimized and model response equations were obtained, enabling the prediction of biodiesel production from the values of the four main factors. It would seem that the reaction temperature and the amount of water predominantly determined the conversion process while the methanol/oil molar ratio had no significant influence on the reaction rate. The temperature and amount of water showed negative interactive effects on the observed reaction rate per amount of enzyme. However, there were no significant interactions among the other variables according to the test of statistical significance. The highest yield of 10.15 mol kg-1 enzyme was observed at 45 °C with a 6:1 methanol to oil molar ratio and with no added water in the system.

 

Keywords: lipases from Rhizomucor miehei; biodiesel; response surface methodology.

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J. Serb. Chem. Soc. 73 (2) 157–167 (2008)
UDC 542.92:664.29+582.734.3; JSCS–3698; doi: 10.2298/JSC0802157N; Original scientific paper

Characterization and degradation of pectin derived from Budimka apple
MILOS V. NIKOLIC and LJILJANA MOJOVIC*
"Srbijanka" Food-Processing Industry, 14 000 Valjevo,
Serbia

*Faculty of Technology and Metallurgy, Department of Biochemical Engineering and Biotechnology University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia

(Received 26 February, revised 1 August 2007)

The characterization of apple pectin and its oligogalacturonic fractions derived from the autochthones apple variety Budimka, characteristic for central Serbia, is described in this paper. After extraction, the apple pectin was subjected to controlled enzymatic hydrolysis by polygalacturonase (PG) and pectin lyase (PL) from Aspergillus niger and then fractionated by ion-exchange column chromatography on Dowex 1X-8 (200–400 mesh). Saturated oligogalacturonic acids, obtained by controlled hydrolysis with PG, were efficiently separated by elution with a gradient of Na acetate buffer (pH 6.0), while unsaturated oligogalacturonic acids, obtained by controlled hydrolysis with PL, were separated on the same resin, using a gradient of Na formate buffer (pH 4.7) as the eluent. The yields of the fractions with the particular degree of polymerization (DP) were also determined. The total content of neutral saccharides in the original Budimka apple pectin was detected by HPLC analysis of the 4-nitrobenzoyl derivatives of the sugar, and amounted to 5.31 %. Among the neutral saccharides, contents of galactose, glucose, rhamnose, arabinose, xylose and mannose were detected.

 

Keywords: synergistic degradation; fractionation; oligogalacturonic acids; Budimka apple pectin; polygalacturonase; pectin lyase; neutral saccharides.

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J. Serb. Chem. Soc. 73 (2) 169–177 (2008)

UDC 546.742+547.466+547.496.2:543.4:543.57; JSCS–3699; doi: 10.2298/JSC0802169G; Original scientific paper

 

Characterization studies and cyclic voltammetry on nickel(II) amino acid dithiocarbamates with triphenylphosphine in the coordination sphere

NATESAN GEETHA and SUBBIAH THIRUMARAN

Department of Chemistry, Annamalai University, Annamalainagar – 608 002, India

 

(Received 18 January, revised 10 July 2007)

Nickel(II) amino acid dithiocarbamate complexes of the composition [Ni(AAdtc)(PPh3)(NCS)], [Ni(AAdtc)(PPh3)(CN)] and [Ni(AAdtc)(PPh3)2]ClO4 [(AAdtc = dithiocarbamate derivatives of amino acids, i.e., glycine (glydtc), L-iso-leucine (i-leudtc) and L-proline (prodtc)] were synthesized. The compounds were characterized by IR and electronic spectroscopy, thermal analysis, cyclic voltammetry and conductivity measurements. In the case of the mixed ligand complexes, the thioureide n(C−N) values were shifted to higher wave numbers compared to [Ni(AAdtc)2]. This observation shows the increased strength of the thioureide bond due to the presence of the p-accepting phosphine. Electronic spectral studies suggest square planar geometry for the complexes. Thermal analyses of the complexes are in keeping with the proposed formulae. Almost all the complexes showed signs of decay above 170 °C. At around 390 °C, the final mass corresponded to NiS. Cyclic voltammetry showed a decrease of the electron density on the nickel in the mixed ligand complexes compared to [Ni(AAdtc)2].

 

Keywords: amino acid dithiocarbamate; triphenylphosphine; nickel(II); IR; electronic spectra; cyclic voltammetry.

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J. Serb. Chem. Soc. 73 (2) 179–187 (2008)

UDC *Organotin(IV)+547.595:542.913; JSCS–3700; doi: 10.2298/JSC0802179H; Original scientific paper

 

Synthesis and structural characterization of organotin(IV) complexes formed with [O,O] donor atoms of carboxylic acids

MUKHTIAR HUSSAIN, MUHAMMAD ZAMAN, MUHAMMAD HANIF, SAQIB ALI and MUHAMMAD DANISH*

Department of Chemistry, Quaid-i-Azam University, Islamabad–45320, Pakistan

*Department of Chemistry, University of Sargodha, Sargodha, Pakistan

 

(Received 14 May, revised 22 October 2007)

Organotin(IV) carboxylates of the general formula RnSnL4-n (where R = Me, n-Bu or Ph, and L = a-phenyl-2,3-(methylenedioxy)cinnamate anion or 2-(2,3-dimethlylanilino)nicotinate anion) have been prepared. The mono-, di- and tri-organotin(IV) carboxylates were synthesized by the reaction of organotin(IV) oxides or hydroxides with a stoichiometric amount of the ligand acids at an elevated temperature in dry toluene. The composition of the synthesized organotin(IV) complexes, the bonding behavior of the donor groups and structural assignments were studied by elemental analysis, FT-IR, 1H-, 13C-NMR and mass spectrometry. The spectral data suggest that the ligand acts in a bidentate manner, coordinating through the oxygen atoms. These spectroscopic techniques revealed a distorted tetrahedral geometry in the solution state for the tri-organotins, while a mean coordination number between five to six for the di-organotin(IV) dicarboxylates. In the solid phase, the tri-organotins were essentially trigonal bipyramidal polymeric while the di-organotins were octahedral. However, mono-organotin tricarboxylates were predicted to exist in the octahedral state both in solution as well as in the solid phase.

 

Keywords: organotin(IV) complexes; O-donor ligands; IR, NMR and mass spectrometry.

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J. Serb. Chem. Soc. 73 (2) 189–195 (2008)

UDC 519.17:547.233’237+546.922:547.97; JSCS–3701; doi: 10.2298/JSC0802189M; Original scientific paper

 

Q-Conjugacy character and Markaracter tables of tetraammineplatinum(II)

ALI MOGHANI

Department of Color Physics, Institute for Colorants, Paints and Coatings (ICPC), Tehran, Iran

 

(Received 7 May, revised 8 June 2007)

The Q-conjugacy character and Markaracter tables of finite groups were introduced by Fujita, who applied his results in this area of research to enumerate isomers of molecules. In this paper, these tables are computed for tetraammineplatinum(II).

 

Keywords: Franck–Condon factors; r-centroids and isotopic molecule SbO and SbP molecules.

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J. Serb. Chem. Soc. 73 (2) 197–209 (2008)

UDC 546–328+54–145.2:543.422.25; JSCS–3702; doi: 10.2298/JSC0802197B; Original scientific paper

 

A study of 12-tungstosilicic and 12-molybdophosphoric acids in solution

DANICA BAJUK-BOGDANOVIC, IVANKA HOLCLAJTNER-ANTUNOVIC, MARIJA TODOROVIC*, UBAVKA B. MIOC and JOANNA ZAKRZEWSKA**

Faculty of Physical Chemistry, P.O. Box 47, 11158 Belgrade 118, Serbia

*Faculty of Chemistry, P.O. Box 157, 11001 Belgrade, Serbia

**Institute of General and Physical Chemistry, P.O. Box 551, 11001 Belgrade, Serbia

 

(Received 21 February, revised 19 September 2007)

The behaviour of two heteropolyacids (HPAs) with quite different stability in aqueous solutions was systematically investigated by UV, IR and NMR spectroscopy and potentiometric titration. It was shown that the Keggin structure of 12-tungstosilicic acid (H4SiW12O40, WSiA) anion was sustained over a wide range of pH from 1.0 to 7.0, while the same anion type of 12-molybdophosphoric acid (H3PMo12O40, MoPA) was present only at pH 1.0. This means that under physiological conditions WSiA is dominantly present in the form of a Keggin-anion, whereas the structure of MoPA is completely decomposed to molybdate and phosphate. The obtained results are of special importance for bio-medical and catalytic applications of these compounds and for a better understanding of the mechanism of their action.

 

Keywords: heteropolyacids of Keggin structure; 12-tungstosilicic acid; 12-molybdophosphoric acid; hydro-stability; UV; IR and NMR spectroscopy.

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J. Serb. Chem. Soc. 73 (2) 211–219 (2008)

UDC 546.74’22+66.094.3:531.3+541.124; JSCS–3703, doi: 10.2298/JSC0802211S; Original scientific paper

 

Mechanism and kinetics of the oxidation of synthetic a-NiS

NADA STRBAC, DRAGANA ZIVKOVIC, IVAN MIHAJLOVIC, BOYAN BOYANOV* and ZIVAN ZIVKOVIC

University of Belgrade, Technical Faculty, Vojske Jugoslavije 12, Bor, Serbia

*University “Paisiy Hilendarsky”, Tsar Assen 24, 4000 Plovdiv, Bulgaria

 

(Received 29 March, revised 4 September 2007)

The results of an investigation of the mechanism and kinetics of the oxidation process of synthetic a-NiS are presented in this paper. The mechanism of a-NiS oxidation was investigated based on the comparative analysis of DTA–TG–DTG and XRD results, as well as the constructed phase stability diagrams (PSD) for the Ni–S–O system. The kinetic investigations of the oxidation process were performed under isothermal conditions (temperature range 823–1073 K). The obtained degrees of desulfurization were used in the calculation process according to the Sharp model and the kinetic parameters, including the activation energies and the rate constants of the characteristic reactions, for the oxidation of a-NiS were determined. These results enabled the formulation of a kinetic equation for the desulfurization process: ‑ln(1−a) = k1t = 27.89 exp(–9860/T)t, with an activation energy of 82±4 kJ mol-1, for the first stage of the process and –ln (1 − a) = k2t = 1.177 exp(–4810/T)t, with an activation energy of 40±2 kJ mol-1, for the second stage.

 

Keywords: anti-inflammatory agents; potentiometric titration; artificial neural network (ANN).

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J. Serb. Chem. Soc. 73 (2) 221–226 (2008)

UDC 546.47+546.175–323+544.35:66.082.2:620.193; JSCS–3704; doi: 10.2298/JSC0802221C; Original scientific paper

 

Periodic current oscillations of zinc in nitric acid solutions

FLORIN CRISAN and ERVIN SALLÓ*

County Lab for Pesticides Quality Control, Bodrogului Str. 3, 310059, Arad, Romania

*Chemistry Institute of Romanian Academy, Mihai Viteazul Blvd. 24, 300223, Timisoara, Romania

 

(Received 22 September 2006, revised 13 June 2007)

The charge percolation mechanism (CPM) of olefin polymerization in the presence of transition metal compounds has been applied to explain the polymerization of ethylene by silica supported chromium oxide. In the previous work of this series, the fundamental issues and mechanism of this polymerization were presented. In this work the compatibility of the CPM with the empirical findings is confirmed. The CPM has been applied to explain: the appearance of an induction period; the deactivation of active centers and the formation of oligomers; the effects of chromium concentration on the silica surface, the silica surface discontinuity and the pore size of silica on polymerization and the formation of the structure of polyethylene. A mathematical model has been derived to explain the effects of the CrOx/SiO2 ratio on the productivity of Phillips catalysts in the polymerization of ethylene. The empirical findings have also been confirmed by computer simulations.

 

Keywords: ethylene polymerization; Phillips CrOx/SiO2; charge percolation mechanism.

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J. Serb. Chem. Soc. 73 (2) 227–231 (2008)

UDC 535.513+512.77+517968.2:541.138–034:681.5.017; JSCS–3705; doi: 10.2298/JSC0802227Z; Note

 

NOTE

The validity of the general polarization curve equation approximation for the process of metal deposition

PREDRAG M. ZIVKOVIC, BRANIMIR N. GRGUR and KONSTANTIN I. POPOV

Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia

 

(Received 15 June, revised 28 September 2007)

Digital simulation was employed for the solution of the general polarization curve equation of metal deposition processes. By approximating the dependence of the exchange current density on concentration with a linear function for one- and two-electron transfer processes, an error lower than 20 % was obtained.

 

Keywords: polarization curve equation; metal deposition; exchange current density; simulation.

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J. Serb. Chem. Soc. 73 (2) 233–247 (2008)

UDC 547.869+615.32:543.4/.5; JSCS–3706; doi: 10.2298/JSC0802233K; Original scientific paper

 

Individual and simultaneous determinations of phenothiazine drugs using PCR, PLS and (OSC)–PLS multivariate calibration methods

MOHAMMAD ALI KARIMI*,**,***, MOHAMMAD MAZLOUM ARDAKANI****, REZA BEHJATMANESH-ARDAKANI**, MOHAMMAD REZA HORMOZI NEZHAD***** and HAMZEH AMIRYAN**

*Department of Chemistry, Payame Noor University of Sirjan, Sirjan, Iran

**Department of Chemistry, Payame Noor University of Ardakan, Ardakan, Iran

***Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran

****Department of Chemistry, Yazd University, Yazd, Iran

*****Department of Chemistry, Persian Gulf University, Bushehr, Iran

 

(Received 14 September 2006, revised 24 July 2007)

Individual and simultaneous determinations of some phenothiazine drugs are described. The individual determination method is based on the reaction of chlorpromazine hydrochloride (CPH), promethazine hydrochloride (PH), trifluoperazine hydrochloride (TFPH), trimipramine maleate (TPM) and thioridazine hydrochloride (TRDH) with complex of [Fe(Bpy)3]3+. In the presence of phenothiazine derivatives, [Fe(Bpy)3]3+ is reduced easily to the coloured complex [Fe(Bpy)3]2+, which shows an absorption maximum at 525 nm. The individual method is highly sensitive and suitable for 0.3–190 mg ml-1 concentrations, with detection limits in the range 0.18–2.46 mg ml-1. Simultaneous kinetic–spectrophotometric determination of ternary mixture of CPH, PH and TPM using principal component regression (PCR), partial least squares (PLS) and orthogonal signal correction (OSC)–PLS multivariate calibration methods is also described. The simultaneous methods are based on the difference observed in the reduction rate of the [Fe(Bpy)3]3+ complex with CPH, PH and TPM in acidic media. The results showed that the simultaneous determination of CPH, PH and TPM can be performed in the concentration ranges of 0.5–120.0, 0.3–80.0 and 5.0–100.0 µg ml-1, respectively, for three methods (PCR, PLS and OSC–PLS). The root mean square errors of prediction (RMSEP) of CPH, PH and TPM were 0.346, 0.663 and 0.820 (for PCR) 0.317, 0.659 and 0.830 (for PLS) and 0.087, 0.124 and 0.085 (for OSC–PLS), respectively. The proposed methods were successfully applied to the individual and simultaneous determination of phenothiazine derivatives in pharmaceutical preparations, the results of which compared well with those obtained by the official method, and several synthetic (spiked) samples, whereby satisfactory results were obtained.

 

Keywords: individual and simultaneous determinations; phenothiazine drugs; PLS; PCR; OSC–PLS.

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J. Serb. Chem. Soc. 73 (2) 249–258 (2008)

UDC 546.56+54–145.2+546.185–323:543.42+543:541.183; JSCS–3707; doi: 10.2298/JSC0802249G; Original scientific paper

 

Determination of trace copper in water samples by flame atomic absorption spectrometry after preconcentration on a phosphoric acid functionalized cotton chelator

RENMIN GONG, DEMIN ZHANG, KEDING ZHONG, MIN FENG and XINGYAN LIU

The Laboratory of Bio-Macromolecular Evolution, College of Life Science, Anhui Normal University, Wuhu, 241000, P. R. China

 

(Received 20 February, revised 8 August 2007)

This paper reports the preparation of a phosphorylated cotton chelator (PCC) by solid phase esterification of phosphoric acid (PA) onto defatted cotton fibres using urea as the catalyst. The synthesized PCC was employed for the preconcentration of copper from water samples prior to its determination by flame atomic absorption spectrometry (FAAS). The preconcentration of copper was studied under both batch and column techniques. The pH range for the quantitative preconcentration of copper was 4.0–7.0. The sorption time required for each sample was less than 30 min by the batch method. The copper sorption capacity of the PCC was found to be 15.3 mg/g at the optimum pH value. Elution with 1.0 mol dm-3 hydrochloric acid was found to be quantitative. Feasible flow rates of the copper solution for quantitative sorption onto the column packed with PCC were 0.5–4.0 ml min-1, whereas the optimum flow rate of the hydrochloric acid solution for desorption was less than 1.5 ml min-1. An 80-fold preconcentration factor could be achieved under the optimum column conditions. The tolerance limits for common metal ions on the preconcentration of copper and the number of times of column reuse were investigated. The proposed method was successfully applied for the preconcentration and determination of trace copper in natural and drinking water samples by FAAS.

 

Keywords: phosphoric acid; PCC; trace copper; preconcentration; FAAS; determination.

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Copyright & copy; SHD 2008.
February 11, 2008.
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