J. Serb. Chem. Soc. 62(11) 1025-1029 (1997)
UDC 547.21:543.542
JSCS-2470
Original scientific paper
Application of line graph in physical chemistry.
Predicting the surface tension of alkenes
IVAN GUTNAM, LJILJANA POPOVIC, BIJAY K. MISHIRA*, MINATI
KUANAR*, ERNESTO ESTRADA** and NICOLAIS GUEVARA**
Faculty of Science, University
of Kragujevac, R. Domanovi}a 12, P.O.Box 60, 34000 Kragujevac, Yugoslavia
*Centre of
Studies of Surface Science and Technology, Department of Chemistry, Sambalpur
University, Jyoti Vihar 768019, India and
**Universidad
Central de Las Villas, Santa Clara 54830, Villa Clara, Cuba
Received 9 April 1997)
For a
molecular graph G we construct a sequence of graphs Li(G), i = 0, 1, 2,..., such that L0(G) = G, L1(G) is the line graph of G, L2(G) is the line graph of L1(G), etc. Let mi be the number
of edges of Li(G). We show that the surface tension of alkanes is well
reproduced by means of linear functions of the invariants mi, i = 0, 1, ...., k.
Satisfactory accuracy (correlation coefficient 0.97) is achieved already at
k = 2.
Key words: line graph, surface tension,
QSPR.
J. Serb. Chem.
Soc. 62(11) 1031-1036 (1997)
UDC 547.82/.825:546.922
JSCS-2471
Original scientific paper
Mechanism of the reactions
between chloro(2,2':6',2''-terpyri-dine)platinum(II) and ligands containing a
thiol group
ZIVADIN D. BUGARCIC,BILJANA V.
DJORDJEVIC and MILOS I. DJURAN
Faculty of Science, Department
of Chemistry, University of Kragujevac, R. Domanovi}a 12, P.O.Box 60, 34000
Kragujevac, Yugoslavia
(Received 23 April 1997)
The
reactions between the [Pt(terpy)Cl]+ complex and ligands with a thiol group, such as
cysteine and thioglycolic acid, have been studied by 1H-NMR spectroscopy in d4-CD3OD
at 22°C. The second-order rate constants at 22°C are (4.9±0.3)×10-2 mol dm-3 s-1 for cysteine and (5.2±0.2)×10-2 mol dm-3 s-1 for thioglycolic acid. However,
methionine, as a thioether ligand, seems to be unreactive under the same
experimental conditions. Steric effects cannot be the main reason for the
difference in reactivity. This difference could be explain by deprotonation of
the thiols, the final product being the thiolate complex [Pt(terpy)(SR)]+. There is no possibility for
the deprotonation in the case of methionine and this could be the main reason
for the difference in the reactivity of thiols (cysteine and thioglycolic acid)
and thioethers (methionine) with [Pt(terpy)Cl]+.
Key words: platinum(II), terpy, complex, thiol,
cysteine, methionine, mechanism.
J. Serb. Chem. Soc. 62(11)
1037-1044 (1997)
UDC 547.864.4:546.733
JSCS-2472
Original scientific paper
The mechanisms of tris(4-morpholinecarbodithioato-S,S')cobalt(III)
complex formation by solid state reaction from ammine cobalt(III) complexes
TIBOR J. SABO, JASNA VLAJKOVIC
and VERA DONDUR*
Faculty of Chemistry and
*Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 16,
P.O.Box 158 & 137, YU-11001 Belgrade, Yugoslavia
(Received 7 February, revised 3 July 1997)
In this
paper, the solid state reaction, conducted with a mixture of
pentaamminechlorocobalt(III) chloride and potassium 4-morpholinecarbodithioate
was investigated under isothermal conditions. The reaction proceeds at
relatively low temperatures (154-192°C). The yield of product solid-solid reaction,
tris(4-morpholinecarbo-dithio-ato-S,S')cobalt(III) complex, does not
exceed 65%. The kinetic of the reaction of powdered and pressed samples were
investigated. The reaction proceeded according to the diffusional mechanism.
Activation energies of 200 kJ/mol and 100 kJ/mol for the powdered and pressed
form, respectively, were obtained.
Key words: cobalt(III) complexes, kinetic,
mechanism, pentaamminechlorocobalt(III) chloride, potassium
4-morpholinecarbodithioate.
J. Serb. Chem.
Soc.62(11) 1045-1051 (1997)
UDC 547.495.9:543.244.6:535.54
JSCS-2473
Original scientific paper
Investigations of the effect of
the S-arginine chelate conformation on the optical activityof the tris(S-arginine)cobalt(III)
diastereomers
PETAR N. RADIVOJŠA
Faculty of Chemistry, University
of Belgrade, P.O.Box 158, YU-11001 Belgrade, Yugoslavia
(Received 16 May 1997)
The effect
of the S-arginine chelate conformation on the optical activity of
tris(S-arginine)cobalt(III) diastereomers was investigated by means
of circular dichroism (CD). It was found that the l-conformation of the S-arginine
chelate in facial diastereomers of the above complex contributes more to the
negative CD of D-dia-stereomers,
than does the d-conformation
to the positive CD of L-diastereomers.
In addition, it was established that the d-conformation of the S-arginine chelate in
both diastereomers causes only a small difference of the CD of meridional
diasteromers.
Key words: cobalt(III) complex, S-arginine,
circular dichroism, optical activity, chelate conformation.
J. Serb. Chem.
Soc. 62(11) 1053-1057 (1997)
UDC 547.466.22:542.9
JSCS-2474
Note
NOTE
Synthesis
and characterization of s-cis-bis(ethylenediamine- -N,N'-diacetato)-µ-O,O'-glycinato-µ-hydroxo-dichromium(III)
monohydrate
TIBOR J. SABO, SLADJANA
SAMARDZIJA*, DEJAN POLETI** and SRECKO R. TRIFUNOVIC***
Faculty of Chemistry, P.O.Box
158, YU-11001 Belgrade,
*Faculty of
Veterinary Medicine, Bul. JNA 18, YU-11000 Belgrade,
**Department
of General and Inorganic Chemistry, Faculty of Technology and Metallurgy,
P.O.Box 494, YU-11001 Belgrade, and
***Department
of Chemistry, Faculty of Science, R. Domanovica 12, YU-34000 Kragujevac,
Yugoslavia
(Received 7 February, revised 14 July 1997)
The
reaction between s-cis-diaqua-(ethylenediamine-N,N'-diacetato)-chromium(III)
nitrate and glycine (mole ratio 1:1, pH = 6, 80°C, 2 h) results in the
formation of two nonelectrolytic compounds. One of them was identified as the
title complex. The infrared and electronic absorption spectra, as well as the
magnetic momentum confirm a binuclear structure and the existence of hydroxo
and O,O'-glycinato bridges.
Key words: chromium(III), binuclear complex, edda,
glycine.
J. Serb. Chem.
Soc. 62(11) 1059-1062 (1997)
UDC 661.86:543.253
JSCS-2475
Note
NOTE
Description
of anion coordination in aluminium salt solutions using polarimetry
D. C. CHAMBERLAIN
Arjo Wiggins Ltd, Butler's
Court, Beaconsfield, Bucks, HP9 IRT, England
(Received 3 March, revised 14 May 1997)
Polarimetric
analysis of sucrose inversion was used to study acidity changed by anions
coordinating with aluminium cations in solution. The effects of aluminium
concentration, temperature and anion concentraton were investigated. The method
proved useful for testing non-ideal solutions. Data show polarimetry is a
sensitive indicator of solution acidity but observation from other methods are
required to provide conclusive details of anion coordination modes.
Key words: acidity determination, non-ideal
solutions, Al3+ion - anions coordination
J. Serb. Chem.
Soc. 62(11) 1063-1068 (1997)
UDC: 547.74/.75/678.6/:543.422/.43
JSCS-2476
Original scientific paper
Spectral properties of methylene
blue modified polypyrrole film
RODICA-MARIANA ION, DANA
FLORENTINA BLAIR* and OCTAVIAN RADOVICI*
Zecasin S.A., Photochemistry
Department, Splaiul Independentei 202, Bucharest-79611, Romania, and
*Polytechnical
University, Polizu Street 1, Bucharest, Romania
(Received 18 October 1996, revised 30 May 1997)
In this
paper the UV-Vis spectra of methylene blue incorporated into a polypyrrole
polymer matrix is discussed. The changes of the absorption maxima of methylene
blue in the presence of polypyrrole have been fitted with Gauss type functions
using a PC computer programme. In addition, the aggregation equilibrium for
methylene blue alone and in the presence of polypyrrole is evaluated.
Key words: polypyrrole, methylene blue,
aggregation, conducting polymers.
J. Serb. Chem.
Soc. 62(11) 1069-1075 (1997)
UDC 541.134:537.311.6:543.42
JSCS-2477
Original scientific paper
Investigation of the relation
between the Kramers-Kronig transforms and the stability condition necessary to derive
the faradaic admittance equation involving three state variablesbesides the
electrode potential
XIAOJUAN WU, YONGQUAN ZHANG,
HOUYI MA*, SHULAN LI* and SHENHAO CHEN*
Department of Electronic
Engineering and *Department of Chemistry, Shandong University, Jinan, 250100,
P.R. China
(Received 10 April 1997)
The
transform between the real and imaginary parts of the Faradaic admittance
equation for an irreversible electrode process involving three state variables,
besides the electrode potential, was carried out using one of the
Kramers-Kronig relations. The result that the condition required by the
stability for the derivation process of the equation was also satisfield in the
K-K transforms shows that the equation is a true mathematic model characterizing
the dependance of the Faradic admittance on angular frequency. The use of the
equation, together with a general equivalent circuit, proved a convenient
method to determine electrochemical parameters from EIS with four time
constants.
Key words: Kramers-Kronig transform,
electrochemical impedance spectroscopy (EIS), irrevesible electrode process,
equvivalent circuit, faradic impedance.
J. Serb. Chem.
Soc. 62(11) 1077-1085 (1997)
UDC 547.96/546.72/:546.48'621''815'''
JSCS-2478
Original scientific paper
Binding of toxic cations to
ferritin
JASMINA VIDIC, DESANKA SUZNJEVIC,
MILENKO ERCEG* and DUŠAN VUCELIC**
Institute of General and
Physical Chemistry, P.O.Box 551, YU-11001 Belgrade,
*Forensic
Institute, Kraljice Ane bb, P.O. Box 574, YU-11000 Belgrade and
**Faculty
of Physical Chemistry, University of Belgrade, YU-11000 Belgrade, Yugoslavia
(Received 3 April 1997)
Electrochemical
studies of metalloproteins have a considerable potential in the investigation
of the structure of metal-protein complexes, particularly in view of the heavy
metal pollution effect. In this paper, data obtained by differential pulse
polarography (d.p.p.) using a dropping mercury electrode (DME) are presented,
with regard to the specific interaction of ferritin with Cd2+, Al3+ and Pb2+ from citrate buffer, pH 6.3. It
is possible to more clearly observe the obtained peak current of Pb2+ on the d.p.p. curve after its
binding to ferritin after digestion of the protein coat by trypsin, suggesting
that the Pb2+ ions are probably associated with
the protein core. However, the binding affinity of Cd2+ to ferritin is not high because
the bound Cd2+ ions can be easily removed as
Cd-citrate or as the more stable Cd-EDTA complex. It was also found that Al3+ ions bind rather strongly to
ferritin, probably due to the association with ferric ions present in the
protein core.
Key words: ferritin, differential pulse
polarography, aluminum, lead, cadmium
J. Serb. Chem.
Soc. 62(11) 1087- 1094 (1997)
UDC 539.1/.124:539.4
JSCS-2479
Original scientific paper
The dependence of the mechanical
properties of materials on their electronic structure
A. M. MARICIC, M. V. NIKOLIC, S.
M. RADIC, B. D. STOJANOVIC and M. M. RISTIC
Joint Laboratory for Advanced
Materials of the Serbian Academy of Sciences and Art, Knez Mihailova 35,
YU-11000 Belgrade, Yugoslavia
(Received 1 April 1997)
In this
paper problems of mechanical properties of materials from the viewpoint of
their electronic structure have been investigated. Special attention was paid
to the importance of the statistical weight of stable atomic configurations
(SWASK) for basic explanation of the interdependence of mechanical properties
and electronic structure.
Key words: mechanical properties, electronic
structure, SWASK.
J. Serb. Chem.
Soc. 62(11) 1095-1100 (1997)
UDC 666.762.5:661.68'55''+546.665.4-54-31
JSCS-2480
Original scientific paper
The role of the liquid phase in
the structural changes of ZrO2 within the
Si3N4-ZrO2-CeO2 system
SNEZANA BOŠKOVIC, FEODOR
SIGULINSKI and EMILIJA KOSTIC
Vinca Institute of Nuclear
Sciences, Materials Science Laboratory, P.O.Box 522, YU-11001 Belgrade,
Yugoslavia
(Received 23 April 1997)
The
structural changes of ZrO2 were followed in the Si3N4-ZrO2-CeO2 system at temperatures between 1500°C and 1780°C, in
an argon atmosphere. The dominant crystalline phase of ZrO2 in this system is the
monoclinic form, with Si ions incorporated in the lattice. Ce ions do not
stabilize the ZrO2 c+t modification because CeO2 preferentially takes part in the formation of the
liquid phase.
Key words: composites Si3N4-ZrO2-CeO2, structure, liquid phase.
J. Serb. Chem.
Soc. 62(11) 1101-1111 (1997)
UDC 666.162.7:666.798.2
JSCS-2481
Original scientific paper
Transparent ferroelectric glass
ceramics of the ABO3 type
MILICA
TODOROVIC and LJILJANA RADONJIC*
Faculty of
Technology and Metallurgy, University of Belgrade, Karnegijeva 4, YU-11000
Belgrade, and
*Faculty of
Technology, University of Novi Sad, Bulevar Cara Lazara 1, YU-21000 Novi Sad,
Yugoslavia
(Received 20 September 1996, revised 11 June 1997)
Ferroelectric
glass ceramics based on ABO3 crystals, obtained by the direct crystallization of
the glasses, were investigated. The glass samples, of composition within the
system (Li or Na or K)2 O - (Nb or Ta)2O5 - SiO2 - Al2O3 were prepared by the melting process, after which
they were subjected to crystallization by heat treatment at appropriate
temperatures for appropriate times. It was found that stable glasses could only
be obtained over a very narrow composition range. The Layton mole ratio B/N has
a significant influence on the nucleation rate of the crystal phase. The Kokubo
alumina content is also an important parameter for the transparency of the
glass ceramics. It was found that, besides these two parameters, the type and
content of the alkali metal oxides are also very important for the
crystallization mechanism of the glasses. Lithium ions facilitate the rapidity
of nucleation and the crystal growth of the glasses much more than either
sodium or potassium ions. The mechanism of crystallization of ABO3 crystals is based on phase
separation of the glasses, followed by nucleation of the crystal phase. The
measured values of the dielectric constant and the refractive index show that
these change in a very complex way, depending on the development of the
microstructure.
Key words: ferroelectric glass-ceramics, glass
crystallization, phase separaton, alkali niobate and tantalate glass ceramics.
J. Serb. Chem.
Soc. 62(11) 1113-1120 (1997)
UDC 666.112.4/.7:666.798.2
JSCS-2482
Original scientific paper
Low temperature processes during
the synthesis of lanthanum lead borosilicate glasses
NIKOLA S. BLAGOJEVIC, SNEZANA R.
GRUJIC, ROZALIJA R. NINKOVIC and LJILJANA C. KARANOVIC*
Faculty of Technology and
Metallurgy, Karnegijeva 4, YU-11000 Belgrade and
*Faculty of
Geology and Mining, Djušina 7, YU-11000 Belgrade, Yugoslavia
(Received 14 March, revised 19 June 1997)
Low
temperature processes during the synthesis of PbO-B2O3-SiO2-La2O3 glasses were studied by thermal
analysis of the batch mixture of glasses and X-ray powder diffraction analysis
of samples that crystallized during invesrtigations of the crystallization
ability of the synthesized glasses. The obtained results and available
thermodynamic data indicate the formation of PbO.B2O3, PbO.2B2O3 and La2O3.B2O3.SiO2 in the temperature interval
400-700°C.
Key words: lanthanum lead borosilicate glasses, low
temperature processes, thermal analysis, X-ray analysis.
J. Serb. Chem. Soc. 62(11)
1121-1127 (1997)
UDC 667.622.271-661.55:621.762.2
JSCS-2483
Original scientific paper
Optimal plasma process routes in
the Al-H-N system for aluminum nitride powder production
ZIVOTA G. KOSTIC, PREDRAG Lj.
STEFANOVIC, PAVLE B. PAVLOVIC and
SLOBODAN
DJ. ŠIKMANOVIC
Vinca Institute of Nuclear
Sciences, Laboratory for Thermal Engineering and Energy,
P.O.Box
522, YU-11001 Belgrade, Yugoslavia
(Received 15 October 1996, revised 21 April 1997)
The results
of equilibrium composition and total enthalpy computation, in the temperature
range of 1000 K to 6000 K and under a pressure of 1 bar, for Al - H - N system
are presented in this paper. These data enable mass, temperature and enthalpy
parameter determination, and optimization of the process for ultrafine aluminum
nitride powder production, where aluminum evaporation in a nitrogen plasma is
followed by cooling with ammonia.
Key words: aluminum nitride powder, plasma
synthesis.