JSCS Vol 69, No. 2
Adobe Acrobat version
|
These articles were
created using Adobe Acrobat and some were compressed using WinZip |
To download the latest |
|
|
To download the text of the whole issue
click here |
|
Impresum |
|
J.Serb.Chem.Soc.
69(2)85–92(2004) |
To download this article click here 104 KB |
Alkylation of N-substituted 2-phenylacetAMides:
Benzylation of N-(4-chlorophenyl)-2-phenylacetAMide
DUSAN Z. MIJIN*, VIDA D. JANKOVIC* and SLOBODAN
D. PETROVIC*,**
*Faculty of Technology and Metallurgy,
University of Belgrade, Karnegijeva 4, P. O. Box 3503,11001 Belgrade, Serbia
and Montenegro and
**Hemofarm Group, Beogradski put bb, 26300 Vrsac, Serbia and Montenegro
(Received 3 December
2002, revised 23 September 2003)
Benzylation of N-(4-chlorophenyl)-2-phenylacetAMide
with benzyl chloride in the presence of powdered potassium hydroxide under
various reaction conditions was performed in order to establish the possible
reaction products. Different temperatures and ratios of reactants and solvents
were used. The reactions were also carried out in the presence of different
phase-transfer catalysts in toluene as a solvent. The formation of the reaction
products was followed using gas chromatography. On the basis of the obtained
results, the reactivity and the orientation in the alkylation reaction of the
investigated AMide is discussed.
Keywords: alkylation, benzylation, 2-phenylacetAMides, phase-transfer
catalysis.
|
J.Serb.Chem.Soc.
69(2)93–106(2004) |
To download this article click here 676 KB |
Scanning probe microscopy characterisation of immobilised enzyme molecules on a
biosensor surface: visualisation of individual molecules
DUSAN LOSIC, KEN SHORT*, J. JUSTIN GOODING** and
JOE G. SHAPTER
School
of Chemistry, Physics and Earth Science, The Flinders University of South
Australia, Adelaide 5001, Australia,
*Material
Division, Australian Nuclear Science Technology Organisation, Lukas Heights,
NSW 2234, Australia and
**School
of Chemical Sciences, The University of New South Wales, Sydney, NSW 2052,
Australia
(Received 2 June 2003)
Scanning
probe microscopy techniques were used to study immobilised enzyme molecules of
glucose oxidase (GOD) on a biosensor surface. The study was carried out in
order to optimise atomic force microscopy (AFM) imaging and reveal the
molecular resolution of individual GOD molecules. Chemically modified AFM tips
and the light tapping mode were found to be the optimal conditions for imaging
soft biomolecules such as GOD. The information obtained from the AFM images
included spatial distribution and organization of the enzyme molecules on the surface,
surface coverage and shape, size and orientation of individual molecules. Two
typical shapes of GOD molecules were found, spherical and butterfly, which are
in accordance with the shapes obtained from scanning tunnelling microscopy
(STM) images. Using a model of the orientation of the GOD molecules on the
surface, these shapes are assigned to the enzyme standing and lying on the
surface. After AFM tip deconvolution, the size of the spherical shaped GOD
molecules was found to be 12 ± 2.1 nm in diAMeter, whereas the butterfly shapes
were 16.5 ± 3.3 nm ´10.2 ± 2.5 nm. Corresponding STM images showed smaller
lateral dimensions of 10 ± 1 nm ´ 6 ± 1 nm and 6.5 ± 1 nm ´ 5 ± 1 nm. The
disagreement between these two techniques is attributed to the deformation of
the GOD molecules caused by the tapping process.
Keywords:
atomic force microscopy, scanning tunnelling microscopy, enzyme biosensors,
enzyme immobilisation, glucose oxidase, self-assembled monolayers
|
J.Serb.Chem.Soc.
69(2)107–115(2004) |
To download this article click here 112 KB |
Photochemistry of aromatic ketones in sodium dodecyl sulphate micelles in the
presence of unsaturated fatty acids
DEJAN Z. MARKOVIC
Faculty of Technology,
16000 Leskovac (e-mail: dzmarkovic@ptt.yu)
(Received 15 January
2003)
Laser-flash photolysis has been employed to
characterize the behaviour of the free radicals created in the photochemical
reaction of benzophenone (BZP), as well as of its lipoidal derivative,
benzophenone-4-heptyl-4’-pentanoic acid (BHPA), with chosen unsaturated fatty
acids in sodium dodecyl sulphate micelles. The calculated rate constants were
used to study the “cage effect”, i.e., the recombination of the created
radical-pairs (BZP, BHPA ketyl radical - lipid radical) inside the highly
limited space of the SDS micelles. The “cage effect” appears to be the dominant
event inside SDS micelles, dependent on the structure of both the
reactants-precursors. The fractions of the initially created radical-pairs
which escape the “cage effect” and exit into the surrounding aqueous phase do
not exceed 16 %. This fact is of enormous importance for the self-control of
the pathogenic process of lipid peroxidation.
Keywords: photosensitizers, benzophenone,
free radicals, radical-pairs, micelles.
|
J.Serb.Chem.Soc.
69(2)117–122(2004) |
To download this article click here 104 KB |
PRELIMINARY COMMUNICATION
Unexpected cycloreversion of a tosylated sugar
oxetane under E2 conditions. The facile formation of
2-(2-furanyl)-1,3-dioxolane from a novel 2,5:4,6-dianhydro-L-idose derivative
VELIMIR POPSAVIN, LJUBICA RADIC, MIRJANA POPSAVIN and VERA
CIRIN-NOVTA
Department of Chemistry, Faculty of Science,
University of Novi Sad, Trg D. Obradovica 3, 21000 Novi Sad, Serbia and
Montenegro
(e-mail: popsavin@ih.ns.ac.yu)
(Received 28 July,
revised 22 September 2003)
2,5:4,6-Dianhydro-3-O-p-toluenesulfonyl-L-idose ethylene acetal (4)
was synthesized with the aim of studying its chemical behaviour in the presence
of several basic agents (Bu4NF/MeCN, NaOMe/MeOH, KOBut/ButOH/THF,
and NaH/DMSO). Treatment of 4 with sodium hydride in dimethyl sulphoxide
at room temperature unexpectedly gave the 2-(2-furanyl)-1,3-dioxolane. The
mechanism of the process presumably involved the initial conversion of 4
to the corresponding 2,3-unsaturated derivative 5, followed by a facile
oxetane ring cycloreversion by the elimination of formaldehyde.
Keywords: 2,5-anhydro-L-idose; 2,5:4,6-dianhydro-L-idose; sugar oxetanes;
cycloreversion.
|
J.Serb.Chem.Soc.
69(2)123–135(2004) |
To download this article click here 158 KB |
Investigation of Pd-catalyzed
Co(III)-EDTA/hypophosphite
inhibition reaction kinetics, mechanism and the evaluation of its analytical
application possibilities
N. BIÇER, R. GÜRKAN*, M. AKÇAY* and T.
ALTUNATA**
Department of
Biochemistry, Medical School, University of Dokuz Eylül, 35200 Inciralti,
Izmir, Turkey,
*Department of Chemistry, Faculty of Science and Arts, University of
Cumhuriyet, 58140 Sivas, Turkey and
**Department of Chemistry, Faculty of Science, University of Ege, 35100
Bornova, Izmir, Turkey
(e-mail address:
rgurkan@cumhuriyet.edu.tr)
(Received 28 July,
revised 1 October 2003)
The reaction between Co(III)-EDTA and hypophosphite ion, catalyzed by Pd(II)
was chosen as the indicator reaction. The inhibition kinetics of this catalytic
reaction have been investigated by a mechanistic approach in the presence of
some inhibitors. Catalysts other than PdCl2, that is Pt, Au, Ni
salts, did not exhibit any effect on the reaction. An original reaction mechanism
is proposed based on the experimental data. The important variables were
optimized for maximum sensitivity. The calibration graph, which was prepared
following the inhibition kinetic method, showed a linear relationship (r = –
0.9878) between the initial rate and iodide in the concentration range of 2–35
ng/cm3 I- with a detection limit of 1.2 ng/cm3
I- (3Sb/m criterion). The RSDs of the method, (N = 5) for
7 and 14 ng/cm3 were 1.19 and 0.81 %, respectively, depended on
iodide concentration. The method was only applied to the determination of
iodide in water, urine, iodized table salt and some drug sAMples and was
compared with the modified Sandell–Kolthoff method.
Keywords: Co(III)-EDTA/hypophosphite,
inhibition kinetics, iodide and some AMino acid determination, kinetic
spectrophotometry and initial rate method.
|
J.Serb.Chem.Soc.
69(2)137–143(2004) |
To download this article click here 97 KB |
The synthesis and characterization of complexes
of zinc(II), cadmium(II), platinum(II) and palladium(II) with potassium
3-dithiocarboxy-3-aza-5-AMinopentanoate
ZORICA LEKA, SLOBODAN A. GRUJIC, ZIVOSLAV TESIC**, SVETLANA LUKIC***, SONJA
SKUBAN*** and SRECKO TRIFUNOVIC*
Faculty of Metallurgy
and Technology, University of Montenegro, Podgorica,
*Department of Chemistry, Faculty of Science, University of Kragujevac, P. O.
Box 60, Kragujevac (e-mail: srecko@knez.uis.kg.ac.yu.),
**Faculty of Chemistry, University of Belgrade, P. O. Box 158, Belgrade and
***Institute of Physics, Faculty of Science, Novi Sad, Serbia and Montenegro
(Received 7 April, revised 12 September 2003)
Complexes of zinc(II), cadmium(II), platinum(II)
and palladium(II) with a new polydentate dithiocarbAMate ligand,
3-dithiocarboxy-3-aza-5-AMinopentanoate (daap-), of the type M(daap)2·nH2O
(M = Zn(II), Cd(II), n = 2, or M = Pt(II), Pd(II), n = 0), have
been prepared and characterized by elemental analysis, IR and UV/VIS
spectroscopy, as well as magnetic measurements. The spectra of the complexes
suggest a bidentate coordination of the daap- ligand to the metal
ions via the sulfur atoms of the deprotonated dithiocarbAMato group. The
fact that under the sAMe experimental conditions its S-methyl ester does not
form complexes could be taken as proof of the suggested coordination mode.
Keywords: zinc(II),
cadmium(II), platinum(II), palladium(II), complexes, synthesis, dithiocarbAMate.
|
J.Serb.Chem.Soc.
69(2)143–151(2004) |
To download this article click here 94 KB |
The adsorption characteristics and porous structure of bentonite adsorbents as
determined from the adsorption isotherms of benzene vapor
SNEZANA BREZOVSKA, BILJANA MARINA, BILJANA PANOVA, DONCO BUREVSKI, VASA
BOSEVSKA and LEPA STOJANOVSKA
Faculty of Technology
and Metallurgy, “St. Kiril and Metodij” University, Skopje, Macedonia
(Received 7 July, revised
22 September 2003)
Abstract: The adsorption of benzene vapor on
natural and acid activated bentonites was treated by the theory of volume
filling of micropores. The micropore volume and characteristic values of the
free energy of adsorption were determined from the adsorption isotherms. The
Dubinin–Radushkevish–Stoeckli and Dubinin–Astakhov equations were used for this
purpose. The results showed that natural bentonite has a more homogeneous
micropore structure than the acid activated ones. The characteristic values of
the free energy of adsorption for the natural bentonite were higher than those
of the acid activated bentonite. This is due to differences in its structure
and the pore size.
Keywords: adsorption, bentonite, chemical
activation, Dubinin–Radushkevich–Stoeckli and Dubinin–Astakhov equations.
|
J.Serb.Chem.Soc.
69(2)153–166(2004) |
To download this article click here 431 KB |
Electrochemical formation and characterization
of Ag2O
B. M. JOVIC and V. D. JOVIC
Center for
Multidisciplinary Studies, University of Belgrade, P. O. Box 33, 11030
Belgrade, Serbia and Montenegro
(Received 2 September
2003)
The process of Ag2O formation has
been investigated in 0.1 M, 0.3 M, 1.0 M and 2.0 M NaOH solutions on
polycrystalline Ag electrodes by cyclic voltAMmetry, potentiostatic pulse and
SEM techniques. The SEM micrographs of the chemically polished Ag surface and
the surface after oxide formation revealed considerable roughening of the Ag
surface after Ag2O formation and reduction. The roughening was more
pronounced at higher NaOH concentrations, indicating that only the first cycle
or pulse applied on a freshly polished Ag electrode should be considered in
mechanistic studies of Ag2O formation. In the given range of NaOH
concentrations, it was shown that the process is not controlled simply by the
diffusion of the reacting species. A nucleation phenomenon was clearly detected
in all the exAMined solutions. The SEM micrographs confirm that the two anodic
peaks, present on the voltAMmogrAMs of Ag2O formation, correspond to
two types of oxide film, i.e., non-homogeneously and homogeneously distributed
ones. Potentiostatic formation of the oxide at potentials corresponding to the
first and second anodic peak yielded simple cubic Ag2O but of very
different grain size.
Keywords: Ag2O formation, 3D
nucleation and growth, morphology, surface roughening.
|
J.Serb.Chem.Soc.
69(2)167–173(2004) |
To download this article click here 290 KB |
Thermostability and surface morphology of nano-
and micro-filled NBR/CSM and CR/CSM rubber blends
G. MARKOVIC, B. RADOVANOVIC*, J. BUDINSKI SIMENDIC** and M.
MARINOVIC-CINCOVIC***
”Tigar” Enterprise,
Pirot,
*Faculty of Science, Nis,
**Faculty of Technology, Novi Sad and
***Vinca Institute of Nuclear Science, Belgrade, Serbia and Montenegro
(e-mail: dopetrov@tigar.com)
(Received 8 January,
revised 7 November 2003)
Acrylonitrile-butadiene rubber (NBR),
polychloroprene rubber (CR), chlorosulphonated polyethylene rubber (CSM) and
their blends were cross-linked with sulphur, ethylene-thiourea, magnesium oxide
or their combination. The effect of nano- and micro- particle sized of 35 pphr
SiO2 on the thermostability and surface morphology of all the
crosslinked systems was investigated. Identification of the structure of nano-
and micro- particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems
was carried out by Fourier transform infrared spectroscopy (FTIR) with an
attenuated total reflectance (ATR) extension. The thermal stability of the
nano- and micro- particle sized SiO2 filled NBR/CSM and CR/CSM
crosslinked systems were carried out by thermogravimetric analysis (TGA). The
glass transition temperature (Tg) of the sAMples was
determined by differential scanning calorimetry (DSC). The morphology of the
fracture surface of the crosslinked systems was carried out by scanning
electron microscope (SEM). The results show when filled with nano-particle
sized of SiO2 NBR/CSM and CR/CSM polymer matrix have a strong peak
from SiO–C at 1079 cm-1. This suggests the an interaction between
the SiO2, which should lead to an increased thermal stability,
higher values of Tg, better dispersion the nano-SiO2
and more polish, without cracks than micro-filled NBR/CSM and CR/CSM
crosslinked systems.
Keywords: IR spectral analysis, thermal
stability, glass transition temperature, surface morphology, nano- and micro-
particle size of SiO2 filled NBR/CSM and CR/CSM crosslinked systems.
Copyright &AMp; copy; SHD 2004.
February
23, 2004.
For
more information contact: SHD@tmf.bg.ac.yu