Vol 78, No 12 - Abstracts

JSCS Vol 78, No. 12

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Publication of this issue is financially co-supported by

Faculty of Technology and Metallurgy, University of Belgrade and

ICTM - Institute of Chemistry, Technology and Metallurgy, University of Belgrade

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EDITORIAL

This issue of the Journal of the Serbian Chemical Society is dedicated to Professor Branislav Ž. Nikolić on the occasion of his 70^th birthday as the tribute to his accomplishments in the field of Electrochemistry and to his contributions to the advancement of Chemistry in Serbia. In parallel with his scientific work, Professor Nikolić was a dedicated teacher of Physical Chemistry and Electrochemistry for generations of students at the University of Belgrade.

The articles in this issue are contributions of Professor Nikolić’s colleagues, friends and students from all over the world. In addition to articles from the area of Electrochemistry, there are a number from several fields of Chemistry illustrating Professor Nikolic’s diverse interests. Technical limitations determined the size of this issue, and we are sorry that we could not invite more contributors.

It was a great pleasure and honor for us to be the Guest Editors of this special issue. We are indebted for the great help from several colleagues and to the Society’s office and the Journal’s teAM for their support in the processing of this issue. The additional financial support of the Faculty of Technology and Metallurgy and Institute of Chemistry, Technology and Metallurgy is very much appreciated.

Belgrade, Serbia/Upton, New York, December 2013

Guest Editors

Radoslav Adžić and Bogdan Šolaja

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J. Serb. Chem. Soc. 78 (12) 1839–1845 (2013)

UDC 929 Branislav Ž. Nikolić

PREFACE

Professor Branislav Ž. Nikolić - On the occasion of his 70^th Birthday

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J. Serb. Chem. Soc. 78 (12) 1847–1864 (2013)

UDC *Clostridium botulinum+547.583.5:615.285:612.014.46+616.8+615.9+57; JSCS–4536; doi: 10.2298/JSC130924112T Original scientific paper

New 9-AMinoacridine derivatives as inhibitors of botulinum neurotoxins and P. falciparum malaria

MIKLOŠ TOT, DEJAN M. OPSENICA*, MILENA MITRIĆ, JAMES C. BURNETT**, LAURA GOMBA***, SINA BAVARI**** AND BOGDAN A. ŠOLAJA

Faculty of Chemistry, University of Belgrade, Studentski trg 16, P. O. Box 51, 11158, Belgrade, Serbia

*Institute of Chemistry, Technology, and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

**SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, P. O. Box B, Frederick, MD 21702, USA

***United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA

****United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, 1425 Porter Street, Frederick, MD 21702, USA

(Received 24 September, revised 20 October 2013)

Steroidal and adAMantane AMinoacridine derivatives were prepared and tested as both botulinum neurotoxin (BoNT) inhibitors and antimalarials. Steroid-bound acridines provided good potency against both the BoNT/A and BoNT/B light chains (LCs). The observed inhibition of the BoNT/B LC by ca. 50 % is the highest attained inhibitory activity against this serotype by acridine-based compounds to date. With respect to the antimalarial activity, the adAMantane acridines were the most potent derivatives (IC50 = 6–9 nM, SI > 326), indicating that an adAMantyl group is a better carrier than a steroidal motif for this indication.

Keywords: antiviral, BoNT/A; BoNT/B; antimalarial; AMinoacridine.

Full Article - PDF 921 KB Supplementary Material PDF 664 KB Available OnLine: 22. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1865–1874 (2013)

UDC 576.315:577.23:57.089:547.857+537.872; JSCS–4537; doi: 10.2298/JSC131118141G Original scientific paper

Purinergic responses of chondrogenic stem cells to dynAMic loading

IVANA GADJANSKI*,** AND GORDANA VUNJAK-NOVAKOVIC*

*Department of Biomedical Engineering, Columbia University, New York, NY, USA

**R&AMp;D Center for Bioengineering, Belgrade Metropolitan University, Serbia

(Received 18 November, revised 21 November 2013)

In habitually loaded tissues, dynAMic loading can trigger ATP (ade-nosine-5ʹ-triphosphate) release to the extracellular environment, and result in calcium signaling via ATP binding to purine P2 receptors. In the current study, the purinergic responses (ATP release) of two types of cells: bovine chondrocytes (bCHs) and human mesenchymal stem cells (hMSCs) that were encapsulated in agarose and subjected to dynAMic loading were compared. Both cell types were cultured under chondrogenic conditions, and their responses to loading were evaluated by an ATP release assay in combination with a connexin (Cx)-sensitive fluorescent dye (lucifer yellow – LY) and a Cx-hemichannel blocker (flufenAMic acid – FFA). In response to dynAMic loading, the chondrogenic hMSCs released significantly higher AMounts of ATP(5-fold) in comparison to the bCHs early in culture (day 2). The triggering of LY uptake in the bCHs and hMSCs by dynAMic loading implies opening of the Cx-hemichannels. However, the number of LY-positive cells in the hMSC-constructs was 2.5-fold lower compared to the loaded bCH-constructs, suggesting utilization of additional mechanisms of ATP release. Cx-reactive sites were detected in both the bCHs and hMSCs-constructs. FFA application led to reduced ATP release in both the bCHs and hMSCs, which confirmed the involvement of connexin hemichannels, with more prominent effects in the bCHs than in the hMSCs, further implying the existence of additional mechanisms of ATP release in chondrogenic hMSCs. Taken together, these results indicate a stronger purinergic response to dynAMic loading of the chondrogenic hMSCs than that of primary chondrocytes, by activation of connexin hemichannels and additional mechanisms of ATP release.

Keywords: cartilage; loading; calcium signaling via ATP; ATP binding; Cx-hemichannels.

Full Article - PDF 361 KB Available OnLine: 22. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1875–1892 (2013)

UDC 638.165.8:58.087:581.9:913(497.11); JSCS–4538; doi: 10.2298/JSC130701099L; Original scientific paper

Quality parAMeters and pattern recognition methods as a tool in tracing the regional origin of multifloral honey

KRISTINA B. LAZAREVIĆ, JELENA Đ. TRIFKOVIĆ*, FILIP Lj. ANDRIĆ*, ŽIVOSLAV Lj. TEŠIĆ*, IVAN B. ANĐELKOVIĆ**, DEJAN I. RADOVIĆ***, NEBOJŠA M. NEDIĆ**** and DUŠANKA M. MILOJKOVIĆ-OPSENICA*

Center for Food Analysis, Zmaja od Noćaja 11, 11000 Belgrade, Serbia

*Faculty of Chemistry, University of Belgrade, P. O. Box 51, 11158 Belgrade, Serbia

**Innovation Center, Faculty of Chemistry Ltd., Studentski trg 12–16, 11000 Belgrade, Serbia

***Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia

****Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia

(Received 1 July, revised 19 September 2013)

Multifloral honey was characterized in regards mineral to composition, sugar content and basic physicochemical properties. A total of 164 honey sAMples were collected from different regions of Serbia during the harvesting season 2009. Univariate data analysis (descriptive statistics and analysis of variance), geographic information system and pattern recognition methods (principal component analysis and cluster analysis) were utilized in order to identify the geographical origin of honey. The content of Mg, K, and Cu, electrical conductivity and optical rotation were established as useful indicators in tracing regional differences between honey sAMples. SAMples originating from Zlatibor region were clearly distinguished from those from the rest of Serbia, showing higher K and Mg contents, as well as higher values of optical rotation, electrical conductivity, and free acidity. The influence of the soil composition, and climate conditions, as well as the presence of particular flora on the honey composition is emphasized. The modeling of the geographic origin of honey was attempted by means of linear discriminant analysis.

Keywords: multifloral honey; geographical origin; pattern recognition; Geographic Information System; Serbia.

Full Article - PDF 609 KB Supplementary Material PDF 1,799 KB Available OnLine: 04. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1893–1909 (2013)

UDC 547.416+542.913:678.86:542.62’18:546.185–034.5; JSCS–4539; doi: 10.2298/JSC131009113J; Original scientific paper

3-(MethylAMino)propylAMine as a templating agent in the synthesis of phosphate-based inorganic polymers

SANJA O. JEVTIĆ, NEVENKA Z. RAJIĆ and VENČESLAV V. KAUČIČ*

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

*National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia

(Received 9 October, revised 17 October 2013)

3-(MethylAMino)propylAMine (MPA) was studied as a structure-directing agent (template) in the synthesis of open-frAMework phosphate-based materials. The influence of temperature, mole ratio of reactants, crystallization time and presence of fluoride ions on the crystallization of aluminophosphate, transition metal-substituted aluminophosphate (transition metal – Mn(II), Cr(III) and Co(II)) and zincophosphate was also investigated. MPA exhibited a templating role and in all the as-synthesized crystalline products, it is entrapped in an inorganic lattice interacting with the frAMework via hydrogen or/and electrostatic interactions. According to detailed thermal analysis, the type of interactions seems to be crucial for the thermal behavior of MPA and for the thermal stability of the organic–inorganic crystal system. Structural analysis suggested that the formed crystalline structures had no mutual structural analogy. This indicates that the precise role of the organic (guest) component in nucleation process for the open-frAMework phosphates (host) is very complex as is the nucleation process itself.

Keywords: microporous; aluminophosphates; MAPO; zinc phosphate; open frAMework.

Full Article - PDF 551 KB Available OnLine: 23.10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1911–1924 (2013)

UDC 546.593+547.78+547.466.1+543.422.25+543.552:576+615.9; JSCS–4540; doi: 10.2298/JSC130920105G; Original scientific paper

Solution study under physiological conditions and cytotoxic activity of gold(III) complexes with L-histidine-containing peptides

BILJANA Đ. GLIŠIĆ, ZORKA D. STANIĆ, SNEŽANA RAJKOVIĆ, VESNA KOJIĆ*, GORDANA BOGDANOVIĆ* and MILOŠ I. DJURAN

Department of Chemistry, Faculty of Science, University of Kragujevac, R. Domanovića 12, 34000 Kragujevac, Serbia

*Oncology Institute of Vojvodina, Institutski put 4, 21204 Sremska KAMenica, Serbia

(Received 20 September 2013)

Proton NMR spectroscopy and cyclic voltAMmetry were applied to study the stability of three gold(III) complexes with L-histidine-containing peptides, [Au(Gly–L-His–N,N′,N″)Cl]NO3·1.25H2O (Au1), [Au(L-Ala–L-His–N,N′,N″)Cl]NO3·2.5H2O (Au2) and [Au(Gly–Gly–L-His–N,N′,N″,N′′′)]Cl·H2O (Au3) under physiologically relevant conditions. It was found that tridentate coordination of Gly–L-His and L-Ala–L-His dipeptides, as well as tetradentate coordination of Gly–Gly–L-His tripeptide in Au1, Au2 and Au3 complexes, respectively, stabilized +3 oxidation state of gold and prevented its reduction to Au(I) and Au(0). No release of the coordinated peptides from Au(III) was observed under these experimental conditions. Considering the remarkable stability of the Au1, Au2 and Au3 complexes, their cytotoxic activity was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay toward five human tumor cell lines, MCF-7 (human breast adenocarcinoma), HT-29 (human colon adenocarcinoma), HeLa (human cervix carcinoma), HL-60 (human promyelocytic leukemia), Raji (human Burkitt’s lymphoma) and one human normal cell line MRC-5 (human fetal lung fibroblasts). While the cytotoxic activity of Au1, Au2 and Au3 against investigated human malignant cell lines was strongly cell line dependent, none of these complexes was cytotoxic against normal MRC-5 cell line. This study can contribute to the future development of gold(III)–peptide complexes as potential antitumor agents.

Keywords: gold(III) complexes; L-histidine-containing peptides; ¹H-NMR spectroscopy; cyclic voltAMmetry; cytotoxic activity.

Full Article - PDF 383 KB Available OnLine: 15. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1925–1933 (2013)

UDC 537.12+537.872+519.17:535.566; JSCS–4541; doi: 10.2298/JSC130905092G; Original scientific paper

Estimating the total π-electron energy

IVAN GUTMAN AND KINKAR CH. DAS*

Faculty of Science, University of Kragujevac, P. O. Box 60, 34000 Kragujevac, Serbia and Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia

*Department of Mathematics, Sungkyunkwan University, Suwon 440–746, Republic of Korea, E-mail: kinkardas2003@googlemail.com

(Received 5 September 2013)

The paper gives a short survey of the most important lower and upper bounds for the total π-electron energy, i.e., the graph energy (E). In addition, a new lower and a new upper bound for E are deduced, valid for general molecular graphs. The strengthened versions of these estimates, valid for alternant conjugated hydrocarbons, are also reported.

Keywords: total π-electron energy; graph energy; HMO theory.

Full Article - PDF 368 KB Available OnLine: 24. 09. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1935–1962 (2013)

UDC 531.314:537.872:531.3:539.193; JSCS–4542; doi: 10.2298/JSC131109107P; Original scientific paper

An alternative derivation of (almost-) Watson’s HAMiltonian

MILJENKO PERIĆ

Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12–16, P. O. Box 47, 11158 Belgrade, Serbia

(Received 9 October 2013)

A derivation of the general wave-mechanical HAMiltonian for non-linear molecules is presented. It is based on the transformation of proper classical (HAMilton) momenta into their wave-mechanical counterparts by means of the Podolsky Transformation in its original form. The result is essentially identical to that obtained by Watson in his milestone paper (J. K. G. Watson, Mol. Phys. 15 (1968) 479). While not so elegant as that of the original reference, the way proposed in the present study is conceptually much simpler. This procedure could also be applied to other types of molecular HAMiltonians.

Keywords: Watson’s molecular HAMiltonian; classical kinetic energy; Podolsky transformation.

Full Article - PDF 312 KB Available OnLine: 19. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1963–1973 (2013)

UDC 547.828+544.022+542.913+544.4:51–3; JSCS–4543; doi:10.2298/JSC131120139U; Original scientific paper

Structure–reactivity correlation for the kinetics of the formation reaction of 4-(substituted phenyl)-1,4-dihydropyridines

JOVICA V. UROŠEVIĆ, SAŠA Ž. DRMANIĆ, JASMINA B. NIKOLIĆ, IVAN O. JURANIĆ* and BRATISLAV Ž. JOVANOVIĆ

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

Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

(Received 20 November, revised 28 November 2013)

Quantitative structure–reactivity correlations for the kinetics of the Hantzsch synthesis of 4-(substituted phenyl)-1,4-dihydropyridines in the reaction between ethyl m- and p-substituted 2-benzylideneacetoacetate and the enAMine (ethyl 3-AMinocrotonate) was studied. The reaction kinetics was followed spectrophotometrically. It was found that the reaction correspond to second-order kinetics. Quantitative structure–reactivity correlations of log k were obtained with the corresponding substituent constants (s, s+, sI and ) using the HAMmett and extended HAMmett equation (dual substituent parAMeter, DSP, equation). They showed linear relationships with positive values of reaction constants (r). The obtained data were processed by linear regression analysis. It was confirmed that Michael addition of the enAMine to benzylidene represented the slow step of the reaction with a high positive charge at the benzylidene molecule. MO calculations were performed and they were in agreement with the conclusions derived from the structure–reactivity correlations.

Keywords: 1,4-dihydropyridines; Hantzsch synthesis; Michael addition; HAMmet equation; extended HAMmett equation; MO calculations.

Full Article - PDF 366 KB Available OnLine: 28. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1975–1982 (2013)

UDC 546.831+541.182:544.032.1:541.135–039.6:543.24; JSCS–4544; doi: 10.2298/JSC131021118M; Original scientific paper

Stability of zirconia sol in the presence of various inorganic electrolytes

JELENA P. MARKOVIĆ, SLOBODAN K. MILONJIĆ and VUKADIN M. LEOVAC*

The Vinča Institute of Nuclear Sciences, University of Belgrade, Serbia

*Chemistry Department, Faculty of Sciences, University of Novi Sad, Serbia

(Received 21 October 2013)

The zirconia sol was prepared from a zirconium oxychloride solution by forced hydrolysis at 102 °C. The prepared sol consisted of almost spherical, monoclinic, hydrated zirconia particles of 61 nm in diAMeter. The stability of zirconia sol in the presence of various inorganic electrolytes (LiCl, NaCl, KCl, CsCl, KBr, KI, KNO3 and K2SO4) was studied by the potentiometric titration method. The dependence of the critical concentration of coagulation (ccc) on the dispersion pH was determined for all studied electrolytes. The critical coagulation concentration values for all investigated electrolytes were lower at higher pH values. These values for all 1:1 electrolytes were the sAMe within the range of experimental error. For a given pH value, the cccs of K2SO4 are 3–4 orders of magnitude lower than the corresponding values for the 1:1 electrolytes.

Keywords: zirconia sol; stability; electrolytes; critical coagulation concentration; potentiometric titration.

Full Article - PDF 315 KB Available OnLine: 30. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1983–1992 (2013)

UDC 546.92+546.98+621.039.51:544.478–44+66.094.2+546.21;JSCS–4545; doi: 10.2298/JSC131024117V; Original scientific paper

Pt monolayer shell on hollow Pd core electrocatalysts: scale up synthesis, structure, and activity for the oxygen reduction reaction

MIOMIR B. VUKMIROVIC, YU ZHANG, JIA X. WANG, DAVID BUCETA, LIJUN WU* AND RADOSLAV R. ADZIC

Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA

*Condensed Matter Physics &AMp; Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA

(Received 24 October 2013)

The synthesis, characterization and kinetics of the oxygen reduction reaction (ORR) of a Pt monolayer shell on Pd(hollow), or Pd–Au(hollow) core electrocatalysts are reported. Comparisons between the ORR catalytic activity of the electrocatalysts with hollow cores and those of Pt solid and Pt hollow nanoparticles were obtained using the rotating disk electrode technique. Hollow nanoparticles were made using Ni or Cu nanoparticles as sacrificial templates. The Pt ORR specific and mass activities of the electrocatalysts with hollow cores were found to be considerably higher than those of the electrocatalysts with solid cores. This enhanced Pt activity is attributed to the smooth surface morphology and hollow-induced lattice contraction. In addition, the hollow particles have a mass-saving geometry.

Keywords: platinum overlayer, electrocatalysis, fuel cells, surface strain.

Full Article - PDF 463 KB Available OnLine: 30. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 1993–2005 (2013)

UDC 546.96+546.93+544.478+621.352:539.196:541.574; JSCS–4546; doi: 10.2298/JSC130927111A; Original scientific paper

XPS and STEM study of the interface formation between ultra-thin Ru and Ir OER catalyst layers and Perylene Red support whiskers

LJILJANA L. ATANASOSKA, DAVID A. CULLEN* and RADOSLAV T. ATANASOSKI

3M Co., 3M Center, St. Paul, MN, 55144-1000 USA

*Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 USA

(Received 27 September 2013)

The interface formation between nano-structured Perylene Red (PR) whiskers and the oxygen evolution reaction (OER) catalysts ruthenium and iridium was studied systematically by XPS and STEM. The OER catalyst over-layers with thicknesses ranging from ≈0.1 to ≈50 nm were vapor deposited onto PR ex situ. STEM images demonstrated that, with increasing thickness, Ru and Ir transform from AMorphous clusters to crystalline nanoparticles, which agglomerate with increased over-layer thickness. XPS data showed a strong interaction between Ru and PR. Ir also interacts with PR although not to the extent seen for Ru. At low coverages, the entire Ru deposit was in the reacted state while a small portion of the deposited Ir remained metallic. Ru and Ir bonding occur at the PR carbonyl sites as evidenced by the attenuation of carbonyl photoemission and the emergence of new peak assigned to C–O single bonds. Curve fitting analysis and the derived stoichiometry indicated the formation of metallo–organic bonds. The co-existence of oxide bonds was also apparent.

Keywords: fuel cell, catalyst, surface properties, deposition

Full Article - PDF 859 KB Available OnLine: 21. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2007–2015 (2013)

UDC 544.351–145.82+66.097.3–034+546.212–124+546.74–36:66.097; JSCS–4547; doi: 10.2298/JSC131118136D; Original scientific paper

Electrocatalysis of the HER in acid and alkaline media

NEMANJA DANILOVIC, RAM SUBBARAMAN, DUSAN STRMCNIK, VOJISLAV R. STAMENKOVIC AND NENAD M. MARKOVIC

Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

(Received 18 November 2013)

Trends in the HER were studied on selected metals (M = Cu, Ag, Au, Pt, Ru, Ir and Ti) in acid and alkaline environments. It was found that with the exception of Pt, Ir and Au, due to high coverage by spectator species on non-noble metal catalysts, the experimentally established positions of Cu, Ag, Ru and Ti in the observed volcano relations are still uncertain. It was also found that while the M–Hupd binding energy most likely controls the activity trends in acidic solutions, the trends in activity in alkaline solutions are controlled by a delicate balance between two descriptors: the M–Had interaction and the energetics required to dissociate water molecules. The importance of the second descriptor was confirmed by introducing bifunctional catalysts such as M modified by Ni(OH); e.g., while the latter serves to enhance the catalytic decomposition of water, the metal sites are required for collecting and recombining the produced hydrogen intermediates.

Keywords: volcano plot; HER; hydrogen evolution reaction; acid; alkaline.

Full Article - PDF 395 KB Available OnLine: 19. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2017–2037 (2013)

UDC 546.98+667.287:539.24:66.094.1; JSCS–4548; doi: 10.2298/JSC130909094N; Original scientific paper

Electrochemical and nanogravimetric studies of palladium phthalocyanine microcrystals

ÁKOS NEMES, COLIN E. MOORE and GYÖRGY INZELT

Department of Physical Chemistry, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary

(Received 9 September, revised 19 September 2013)

An electrochemical quartz crystal nanobalance was used to study the redox behavior of palladium phthalocyanine microcrystals attached to gold and platinum in aqueous solutions at different pH values. In order to investigate the substrate effect, paraffin impregnated graphite electrodes were also applied. It was found that the redox transformations of palladium phthalocyanine are accompanied with deprotonation–protonation as well as the sorption and desorption of counter-ions, the extent of which depend on the pH. Based on the results of the nanogravimetric measurements, a redox mechanism describing the pH dependence is suggested. Simultaneously with charge transfer processes, solid–solid phase transitions and water transport occur.

Keywords: palladium phthalocyanine; microcrystals; electrochemical quartz crystal nanobalance (EQCN); redox transformations; solid–solid phase transition.

Full Article - PDF 863 KB Available OnLine: 24. 09. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2039–2052 (2013)

UDC 546.732+547.584.463.1’052.1+547.288.3:66.094.3:544.4–44; JSCS–4549; doi: 10.2298/JSC131024123Z; Original scientific paper

Unusual behaviour of perfluorinated cobalt phthalocyanine compared to unsubstituted cobalt phthalocyanine for the electrocatalytic oxidation of hydrazine. Effect of the surface concentration of the catalyst on a graphite surface

JOSÉ H. ZAGAL, DANIELA A. GERALDO*, MAMIE SANCY** and MARITZA A. PAEZ

Facultad de Química y Biología, DepartAMento de Química de los Materiales Universidad de Santiago de Chile, Casilla 40, Correo 33, Sucursal Matucana, Santiago 9170022, Chile

*DepartAMento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andrés Bello. República 275, Santiago, Chile

**Fuerza Aérea de Chile, Academia Politécnica Aeronáutica, José Miguel Carrera 11085, El Bosque, Santiago, Chile

(Received 24 October 2013)

It was found that CoPc and 16(F)CoPc when adsorbed on a graphite electrode exhibited voltAMmogrAMs in alkaline solution (0.2 M NaOH) that show the typical redox peaks attributable to the reversible Co(II)/(I) redox process. The peak potential for CoPc was independent of the surface concentration of the catalyst. In contrast, for 16(F)CoPc, the Co(II)/(I) redox process shifted to more negative potentials with increasing surface concentration of the catalyst. In a volcano correlation of log (i/G)E (activity per active site) versus the Co(II)/(I) formal potential of the catalyst (using several CoN4 chelates), CoPc appeared in the ascending portion (the activity increased with the Co (II)/(I) redox potential), whereas 16(F)CoPc appeared in the region where the activity decreases with the redox potential. In a plot of log (i/G)E versus the Co(II)/(I) formal potential of 16(F)CoPc, the declining portion of the volcano was reproduced for one single complex. Thus, 16(F)CoPc at different surface concentrations behaved as Co complexes, having different redox potential in the declining portion of the volcano plot, when the activity is normalized to the surface concentration. This was not observed for CoPc.

Keywords: cobalt phthalocyanine; cobalt-hexadecafluoro-phthalocyanine; surface concentration-dependent redox potential; hydrazine oxidation; electrocatalysis.

Full Article - PDF 547 KB Available OnLine: 03. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2053–2067 (2013)

UDC 669.14.018.8+546.3–31:621.315.59+620.193:539.216; JSCS–4550; doi: 10.2298/JSC131121144M; Original scientific paper

Change of n-type to p-type conductivity of the semiconductor passive film on N-steel: Enhancement of the pitting corrosion resistance

MIRJANA METIKOŠ-HUKOVIĆ, ZORAN GRUBAČ* and SASHA OMANOVIC**

Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, P. O. Box 177, 10000 Zagreb, Croatia,

*Department of General and Inorganic Chemistry, Faculty of Chemistry and Technology, University of Split, N. Tesle 10, 21000 Split, Croatia

**Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec, Canada H3A 2B2

(Received 21 November, revised 24 November 2013)

Electrochemically-assisted modification of the surface of N-austenitic stainless steel (ASS N25) was successfully employed to improve the barrier properties of the passive film in a chloride-containing solution. The chemical composition, electronic and barrier properties of the surface film before and after the electrochemical treatment were exAMined using X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical measurements were performed in a corrosion testing solution. The excellent corrosion resistance (both pitting and general) of the modified surface of the N-steel was discussed according to a Mott–Schottky analysis of the interfacial capacitance of the space charge layer and EIS results. The conductivity change of the surface film from an n- to a p-type in the pitting susceptible region was explained using the XPS analysis and the semiconducting properties of the film.

Keywords: stainless steel; corrosion; passive films; metal oxide semiconductors.

Full Article - PDF 2,884 KB Available OnLine: 25. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2069–2086 (2013)

UDC 547.466+546.56:66.097.8:546.131:620.193; JSCS–4551; doi: 10.2298/JSC131126146M; Original scientific paper

Amino acids as corrosion inhibitors for copper in acidic medium: Experimental and theoretical study

INGRID MILOŠEV, JASMINKA PAVLINAC, MILAN HODOŠČEK* and ANTONIJA LESAR

Jožef Stefan Institute, Department of Physical and Organic Chemistry, JAMova 39, SI-1000, Ljubljana, Slovenia

*National Institute of Chemistry, Laboratory for Molecular Modeling, Hajdrihova 19, SI-1000 Ljubljana, Slovenia

(Received 26 November 2013)

Experimental electrochemical methods combined with quantum chemical calculations and molecular dynAMics simulations were emplyed to investigate the possibility for the use of various AMino acids as “green” corrosion inhibitors for copper in 0.5 M HCl solution. Among the eleven studied AMino acids, cysteine achieved the highest inhibitor effectiveness, reaching 52 % at a concentration of 10 mM. The other AMino acids achieved an effectiveness of less than 25 %; some of them even acted as corrosion accelerators. Based on the experimental results, the theoretical calculations and simulations were focused on cysteine and alanine. The electronic and reactivity parAMeters of their protonated forms in an electrical double layer were evaluated by density functional calculations. In addition, molecular dynAMic simulations were introduced to follow the adsorption behaviour of these two AMino acids at the Cu(111) surface in the electrolyte solution. The results indicate that the orientation of both molecules was nearly parallel to the surface except for the AMmonium group, which was directed away from the surface. Therefore, as the orientation of the cysteine and alanine molecules at the surface were similar, the thiol functional group is responsible for the superior inhibition efficiency of cysteine.

Keywords: AMino acids; copper; hydrochloric acid; green inhibitors; quantum chemical calculations; molecular dynAMics.

Full Article - PDF 664 KB Available OnLine: 28. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2087–2098 (2013)

UDC 66.091+544.6:546.57:539.12:678.744+544.35; JSCS–4552; doi: 10.2298/JSC131017124S; Original scientific paper

Electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) solution

RADE SURUDŽIĆ, ŽELJKA JOVANOVIĆ, NATAŠA BIBIĆ*, BRANISLAV NIKOLIĆ and VESNA MIŠKOVIĆ-STANKOVIĆ

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

*Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12–14, 11000 Belgrade, Serbia

(Received 17 October, revised 4 November 2013)

In this work, silver/poly(vinyl alcohol), Ag/PVA, colloidal dispersions were obtained by electrochemical reduction of Ag+. The electrochemical synthesis of silver nanoparticles in aqueous solutions of 5 and 10 wt. % PVA, containing 0.1 M KNO3 and 3.9 mM AgNO3, was performed at a constant current density of 25 mA cm-2 for a synthesis time of 10 min. The presence of silver nanoparticles was confirmed by UV–Vis spectroscopy. Cyclic voltAMmetry analysis and FT-IR spectroscopy indicated interactions between the silver nanoparticles and the PVA molecules. TEM analysis confirmed the spherical shape of the obtained silver nanoparticles, with a mean diAMeter of 15±9 nm.

Keywords: electrochemical synthesis; PVA; silver nanoparticles.

Full Article - PDF 385 KB Available OnLine: 07. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2099–2114 (2013)

UDC 544.6.001.5:546.815–31:66.087+546.11.027*3:544.032.4; JSCS–4553; doi: 10.2298/JSC131022122A; Original scientific paper

An electrochemical and radiotracer investigation on lead dioxide: influence of the deposition current and temperature

ROSSANO AMADELLI, LUCA SAMIOLO and ALEKSANDR B. VELICHENKO*

CNR-ISOF u.o.s. Ferrara c/o Dipartimento di Scienze Chimiche e Farmaceutiche, via Fossato di Mortara, 17, 44121 Ferrara, Italy

*Ukrainian State University of Chemical Technology, Gagarin ave. 8, 49005 Dnipropetrovsk, Ukraine

(Received 22 October 2013)

The properties of electrodeposited PbO2 are sensibly influenced by the deposition current and temperature. In particular, tritium radiotracer measurements demonstrated that protons were incorporated into the bulk of an oxide film and on its surface. The degree of hydration increased with increasing current and decreased with temperature, and was related to the morphological characteristics of the oxide, such as roughness measured by changes in the double layer capacity. Conversely, the AMount of hydrogen had negligible effects on the number of free carriers as evaluated from Mott–Schottky plots. The hydration degree of the surface seems to be an important factor influencing electrocatalytic processes at high potentials, such as O2 evolution and O3 formation. On less hydrated, more crystalline PbO2 surfaces, the first process was inhibited and accordingly, the second was favored.

Keywords: lead dioxide, tritium, electrodeposition, electrocatalysis.

Full Article - PDF 504 KB Supplementary Material PDF 307 KB Available OnLine: 03. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2115–2130 (2013)

UDC 546.131+544.6.076.32–13:66.094.3:541.135:544.4; JSCS–4554; doi: 10.2298/JSC131119142G; Original scientific paper

The kinetics of hydrogen chloride oxidation^·

ISAI GONZALEZ MARTINEZ*, TANJA VIDAKOVIĆ-KOCH**, RAFAEL KUWERTZ***, ULRICH KUNZ***, THOMAS TUREK*** AND KAI SUNDMACHER*^,**

*Otto-von-Guericke University, Process Systems Engineering, Universitätsplatz 2, 39106 Magdeburg, Germany,

**Max-Planck Institute for DynAMics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany

***Institute of Chemical Process Engineering, Clausthal University of Technology, Leibnizstr. 17,38678 Clausthal-Zellerfeld, Germany

(Received 19 November 2013)

Hydrogen chloride (HCl) oxidation was investigated on technical membrane electrode assemblies in a cyclone flow cell. The influences of Nafion loading, temperature and hydrogen chloride mole fraction in the gas phase were studied. The apparent kinetic parAMeters, such as reaction order with respect to HCl, Tafel slope and activation energy, were determined from the polarization data. The apparent kinetic parAMeters suggest that the recombination of adsorbed Cl intermediate is the rate-determining step.

Keywords: gas diffusion electrodes, Nafion, electrolysis, HCl gas phase oxidation, kinetics.

Full Article - PDF 676 KB Available OnLine: 22. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2131–2140 (2013)

UDC 541.132.4+547.292–38+544.6.076.32–039.59:543.544.5.068.7; JSCS–4555; doi: 10.2298/JSC130913116M; Original scientific paper

Determination of clopidogrel using square wave voltAMmetry at a gold electrode

ALEKSANDAR R. MLADENOVIĆ, VLADISLAVA M. JOVANOVIĆ*, SLOBODAN D. PETROVIĆ**, DUŠAN Ž. MIJIN**, SAŠA Ž. DRMANIĆ** AND MILKA L. AVRAMOV IVIĆ*

Hemofarm AD, Beogradski put bb, 26300 Vršac, Serbia

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

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

(Received 13 September 2013)

The determination of clopidogrel, an antiplatelet agent, was performed at a gold electrode in pH 3.7 acetate buffer using cyclic voltAMmetry (CV) and square wave voltAMmetry (SWV). Each voltAMmogrAM was characterized by the well-defined peak at approximately 1.0 V. The current of anodic stripping peak exhibited a linear dependence on the clopidogrel concentration in the range from 317.89 to 935.16 μg cm-3. The obtained linearity was applied to determine clopidogrel in the tablet form of the pharmaceutical preparation (Plavix®). The results were compared to the UV spectrophotometric and HPLC methods.

Keywords: cyclic voltAMmetry; acetate buffer; tablet; UV, HPLC.

Full Article - PDF 283 KB Available OnLine: 31. 10. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2141–2164 (2013)

UDC 546.96–31+546.93–31+661.666.4.004.17:537.872.004.4:543.42; JSCS–4556; doi: 10.2298/JSC131031128P; Authors’ Review

AUTHORS’ REVIEW

Tailoring the supercapacitive performances of noble metal oxides, porous carbons and their composites

VLADIMIR V. PANIĆ, ALEKSANDAR B. DEKANSKI AND BRANISLAV Ž. NIKOLIĆ*

Institute of Chemistry, Technology and Metallurgy, Department of Electrochemistry, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

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

(Received 31 October 2013)

Porous electrochemical supercapacitive materials, as an important type of new-generation energy storage devices, require detailed analysis and knowledge of their capacitive performances under different charging/discharging regimes. An investigation of the responses to dynAMic perturbations of typical representatives, noble metal oxides, carbonaceous materials and RuO2-impregnated carbon blacks, by electrochemical impedance spectroscopy (EIS) is presented. This presentation follows a brief description of supercapacitive behavior and origin of pseudo-capacitive response of noble metal oxides. For all the investigated materials, the electrical charging/discharging equivalent of the EIS response was found to obey the transmission line model envisaged as a so-called “resistor/capacitor (RC) ladder”. The ladder features are correlated to material physicochemical properties, its composition and the composition of the electrolyte. Fitting of the EIS data of different supercapacitive materials to appropriate RC ladders enables in-depth profiling of the capacitance and pore resistance of their porous thin-layers and finally the complete revelation of capacitive energy storage issues.

Keywords: energy storage; pseudo-capacitance; carbon blacks; RuO2; IrO2; electrochemical impedance spectroscopy; transmission line model.

Full Article - PDF 722 KB Available OnLine: 09. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2165–2177 (2013)

UDC 544.6.001.6+62.001.5:001.38; JSCS–4557; doi: 10.2298/JSC131104126H; Essey

ESSAY

The third century of electrochemistry: Lowering the horizon or raising it further?

SVETOMIR HADŽI JORDANOV

Faculty of Technology and Metallurgy, UKIM, Skopje

(Received 4 November 2013)

A survey is given of the development of electrochemistry with the author’s unmasked wish for more advanced development in the future. The survey is based on past achievements of electrochemistry, which is listed concisely herein. As far as the recent state is concerned, author’s dissatisfaction is expressed with the acceptance of electrochemistry as both a favorite professsion of graduate students and a top priority field in the financing of research. For the sake of honesty, an alternative view is mentioned that takes the recent state of electrochemistry as normal and in accordance with the usual course of development, (i.e., birth, rise, achieving of maximum and then decay, fading, etc.) that is common in nature. This statement is based on the belief that today electrochemistry exists on a broader basis than before, and is mainly incurporated into other (new) branches of chemistry and science. ExAMples are given where recent electrochemistry failed to fulfill its promises (e.g., the production of cheap hydrogen by means of electrocatalysts with high performance for H2 evolution, economical use of large-scale fuel cells, etc.). In summarizing the recent fields of interest that cover electrochemistry, their diversification, specialization, complexness and interdisciplinary nature must be stressed. A list of desirable highlights that could possibly help electrochemistry to improve its rating AMong other branches of science is composed. In addition, a list of the author’s personal preferences is given.

Keywords: electrochemistry; lost priority; recovery; desirable highlights; history; current trends; future prospects.

Full Article - PDF 475 KB Available OnLine: 07. 11. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2179–2200 (2013)

UDC 547.462.3+66.092–977:678.7/.8+577.1; JSCS–4558; doi: 10.2298/JSC131214154P; Authors’ Review

AUTHORS’ REVIEW

The thermal degradation of some polymeric di-alkyl esters of itaconic acid

IVANKA POPOVIĆ and LYNNE KATSIKAS

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

(Received 14 December 2013)

Abstract: One group of polymers that may help relieve the dependence on crude oil is based on itaconic acid, the biotechnological production of which has become feasible. Itaconic acid and its derivatives can easily be incurporated into polymers and may serve as a substitute for petrochemically derived acrylate or methacrylate monomers. The applications of polymers based on itaconic di-esters depend largely on their thermal stability. The thermal stability of poly(di-itaconates) is dependent, not only on the general structure of the monomer repeating unit, but also on the structure of the ester substituent. Depolymerization, initiated by b-scission or random main chain scission, is the dominant thermolysis mechanism in most cases. The deploymerization of poly(di-itaconates) may be accompanied by de-esterification, elimination, crosslinking, random main or side chain scission and carbonization. Comparison of the thermal degradation mechanism of polymeric di-esters of itaconic acid to that of corresponding poly(methacrylates) confirms the viability of substituting poly(methacrylates) by poly(di-itaconates).

Keywords: itaconic acid; polyitaconates; thermal degradation; biosynthetic polymers.

Full Article - PDF 797 KB Available OnLine: 16. 12. 2013. Cited by

J. Serb. Chem. Soc. 78 (12) 2201–2214 (2013)

UDC 537.311.35:536.7.004.12+53.004.12+54.004.12:536.416; JSCS–4559; doi: 10.2298/JSC131023129D; Review

REVIEW

Physical, chemical and structural effects as important factors for the determination of thermodynAMic and transport properties and the modelling of non-electrolyte solutions

BOJAN D. DJORDJEVIĆ, MIRJANA Lj. KIJEVČANIN, IVONA R. RADOVIĆ, SLOBODAN P. ŠERBANOVIĆ and ALEKSANDAR Ž. TASIĆ

Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03, 11120 Belgrade, Serbia

(Received 23 October, revised 8 November 2013)

In our previous review, an attempt was made to relate the volumetric effects involved in binary mixtures of normal and branched alcohols. The present paper summarizes some selected research activities related to complex molecular structure of various authors that appeared in leading international journals. The main aim was a better understanding of the complex structure of different non-electrolyte mixtures with no alcohols, which are most frequently present in the chemical, petrochemical and related industries. The influences of the basic physical, chemical and structural effects of the most often chosen types of various binary and ternary mixtures were analyzed. These contributions are of primary importance for the determination and modelling of thermodynAMic, transport and other properties.

Keywords: thermophysical properties; transport properties; non-electrolyte systems; structural effect.

Full Article - PDF 311 KB Available OnLine: 11. 11. 2013. Cited by