J. Serb. Chem. Soc. 62(10) 915-943 (1997)
JSCS-2459
UDK 678.741:535.215
Review
paper
REVIEW
Electrically and optically active polymers
- perspective materials for electronics
STANISLAV NESPUREK
Institute of Macromolecular Chemistry, Academy of Science of the
Chech Republic,
16206 Prague, Chech Republic
(Received
11 October 1996)
1. Introduction
2. Electroactive polymers
3. Photoconductivity
4. From silicon to molecular chips
5. Conclusions
Key
words: polymers, electrical conductivity, optical activity, electronic
materials
J. Serb. Chem. Soc. 62(10) 945-950 (1997)
JSCS-2460
UDK 678.741:537.311.1
Original
scientific paper
Electrical conductivity of poly(acrylic acid) gels
J. V. STAMENKOVIC, P. I. PREMOVIC* and S. V. MENTUS**
Faculty of Technology, Leskovac,
*Faculty of Philosophy, Nis and
**Faculty of Physical Chemistry, YU-11000
Belgrade, Yugoslavia
(Received
6 February, revised 3 May 1997)
Complete solution transformation into
ionically conducting hydrophilic rubber like gels occurs on g-ray polymerization of 1.5 - 10 M aqueous solutions of acrylic
acid. Both the hydrophilicity and conductivity of this material are due to the
volume distributed carboxylic groups. The conductivity of the gels was improved
by addition of strong electrolytes, either sulphuric acid or sodium hydroxide,
to the initial monomer solution. With the addition of sulphuric acid
conductivities exceeding 10-1 S cm-1 were achieved.
Key
words: poly(acrylic acid), electrical conductivity, gels
J. Serb. Chem. Soc. 62(10) 951-955 (1997)
JSCS-2461
UDK 547.852/.7
Original
scientific paper
Structure-activity relations. Part 16. Biologically active
2,4-diphenylphthalazin-1(2H)-ones and 2,6-diphenylpyridazin-3(2H)-ones
KEITH BOWDEN, ANDREW BROWNHILL and FAISAL MALIK
Department of Biological and Chemical Sciences - Central Campus,
University of Essex,
Wivenhoe Park, Colchester, Essex, UK, CO4
3SQ
(Received
25 May 1997)
Molecular graphic studies of a series of
"bleaching" herbicides, which are inhibitors of desaturation of
phytoene, have led to the design, synthesis and study of substituted
2,4-diphenylphthalazin-1(2H)-ones and 2,6-diphenylpyridazin-3(2H)-ones.
The former have been shown to be potent inhibitors of the desaturation of
phytoene and "bleaching" herbicides.
Key
words: "bleaching" herbicides, molecular modeling,
structure-activity relations, desaturation of phytoene
J. Serb. Chem. Soc. 62(10) 957-964 (1997)
JSCS-2462
UDK 547.789.5:547.964
Original
scientific paper
Synthesis of 2-aryl-substituted thiazolidine-4-carboxylic acids
by intramolecular cycloaddition of in situ formed azomethine derivatives
of L-cysteine
RADE MARKOVIC and BILJANA RAJKOVIC
Faculty of Chemistry, University of Belgrade, P.O.Box 158,
YU-11001 Belgrade, Yugoslavia
(Received
21 January 1997)
The azomethines 6, prepared from
aromatic aldehydes and aniline, react with L-cysteine, affording a mixture of
epimeric 2-aryl-substituted thiazolidine-4-carboxylic acids 5, which are
precursors of biologically and medicinally important compounds. The key step is
the formation of the arylidene Schiff base of L-cysteine 7, formed in
situ by the transimination of the original Schiff base 6 with
L-cysteine in the presence of a catalytic amount of mineral acid. The former as
common synthetic intermediate 7, is transformed, via
intramolecular cyclization, into 5 in good yields (57-71.5%).
Key
words: Schiff base, L-cysteine, transimination, cycloaddition, azomethines,
intramolecular cyclization
J. Serb. Chem. Soc. 62(10) 965-975 (1997)
JSCS-2463
UDK
547.315.3:547.5/.517
Original
scientific paper
Structure-reactivity relationship in the Pd(II)-catalyzed
carbonylation of cyclic and acyclic unconjugated dienes
RADE MARKOVIC and CURTIS B. ANDERSON*
Faculty of Chemistry, University of Belgrade, P.O.Box 158,
YU-11001 Belgrade, Yugoslavia
*Department of Chemistry, University of
California, Santa Barbara, CA 93106, USA
(Received
16 January, revised 29 May 1997)
The oxidative catalytic carbonylation under
mild experimental conditions of a series of four dienes with isolated double
bonds, i.e., 1,5-cyclooctadiene, norbonadiene, dicyclopentadiene and
1,5-hexadiene, has been studied. It was shown that the structural characteristics
of the starting cyclic or acyclic diene affect markedly the stereochemical
outcome and reaction pathways in terms on the type and the ratio of
carbonylated versus noncarbonylated products. The conversion of the
stoichiometric carbonylation reaction of the s-Pd(II)-1,5-cyclooctadiene
complex and the Pd(II)-p-complexes of norbornadiene and
dicyclopentadiene in the catalytic process has been investigated from a
preparative purposes, as well as a mechanistic point of view.
Key
words: unconjugated dienes, carbonylation, catalysis, palladium
J. Serb. Chem. Soc. 62(10) 977-986 (1997) J
SCS-2463
UDK 547.83/.832
Original scientific
paper
Quinolones substituted by different moieties. Part 2. Reactions
of 1,2-dihydro-4-hydroxy-1-methyl-2-oxoquinoline-3-carbaldehyde with acyclic
active methylene compounds
MOSTAFA M. ISMAIL, ALIM ABDEL-HALIM and MOHAMED ABASS
Chemistry Department - Faculty of Education, Ain Shams
University, Roxy, Cairo, Egypt
(Received
14 March 1997)
Some interesting heterocycles were
synthsized either as substituents or fused to quinolone moiety, by
condensationof 1,2-dihydro-4-hydroxy-1-methyl-2-oxoquinoline-3-carbaldehyde
with some acyclic active methylene compounds, viz., malonic ester,
acetoacetic ester, malononitrile, cyanocetamide, cyanomethylbenxothiazole and N-acyl
(or benzoyl) glycines. Most of the newly synthesized products were identified
chemically using more than one route for their preparation in order to
elucidate their structures or improve their yield. Most of the obtained
compounds have promising biological activity.
Key
words: substituted quinolones, synthesis, structure elucidation of
J. Serb. Chem. Soc. 62(10) 987-993 (1997)
JSCS-2465
UDK 678.675.66.094.3
Original
scientific paper
Thermooxidative stability of some polyimides
KATARINA POPOV-PERGAL, MIROSLAV PERGAL, DRAGAN BABIC* and MILENA
MARINOVIC*
Institute of Chemistry, Faculty of Science, University of Novi
Sad, Trg Dositeja Obradovica 3, YU 21 000 Novi Sad and *The Vinca Institute of
Nuclear Science, P.O.Box 522, YU-11001 Belgrade, Yugoslavia
(Received
5June 1996, revised 25 February 1997)
Different polyimide resin types were synthesized
using N,N'-4,4'-bis-maleimidodiphenylmethane and five structurally different
diamines. The molecular structure characteristic so used compounds were
obtained by computer analysis. In addition to the previous paper, in which the
thermal stability was studied in nitrogen atmosphere, the thermogravimetric
characterization was performed in oxygen in order to define the thermooxidative
stability of synthesized resins. The results have shown somewhat different
order of thermooxidative stability compared to the findings in nitrogen
atmosphere. The difference was attributed to the different structural
characteristics of the studied samples.
Key
words: polyimides, thermooxidative stability
J. Serb. Chem. Soc. 62(10) 995-1001 (1997)
JSCS-2466
UDK 666.1:661.635.64:66.091
Original
scientific paper
hermal and structural
changes during the synthesis of metaphosphate glass
SLAVICA BOGDANOV, VERICA MLADENOVIC, KATARINA KILIBARDA* and
SVETLANA MITROVSKI**
Military Technical Institute, Kataniceva 15, YU-11000 Belgrade
*Serbian Glass Factory, Technical and
Optical Glass, YU-35230 Paracin and
**ICTM - Center for Catalysis and Chemical
Engineering, Njegoseva 12,
YU-11000 Belgrade, Yugoslavia
(Received
11 October 1996)
Methaphosphate glass was synthesized by
melting a mixture of analytical grade Na-hexametaphosphate, Al-metaphosphate
and silver as silver as silver nitrate. The thermal and structural changes in
the courses of synthesis were investigated by DTA and IR structural analysis.
The characteristic temperatures of glass transformation and softening were
found to be 477°C and 522°C, respectively. The glass was characterized by
measuring its thermal expansion coefficient, index of refraction and optical
density. The glass was characterized by measuring its thermal expansion
coefficient, index of refraction and optical density. the glass was found to be
transparent in the VIS spectral region. The structure of the synthesized glass
corresponded to a mixture of linear polyphosphates and cyclic metaphosphates.
Key
words: metalphosphate glass, dosimeter glass, synthesis
J. Serb. Chem. Soc. 62(10) 1003-1009 (1997)
JSCS-2467
UDK 691.54:662.613.13
Original
scientific paper
Influence of fly ash with low content of 3CaO Al2O3 on the sulfate
resistance of portland cement
MIRJANA CURIC, JONJAUA RANOGAJEC, RADOVAN OMORJAN and SASA
MILETIC*
Faculty of Technology, University of Novi Sad, Bulevar Cara
Lazara 1,
YU-21000 Novi Sad and *Institute for
Material Science, YU-11000 Belgrade, Yugoslavia
(Received
20 September 1996, revised 8 May 1997)
This paper presents an investigation of the
resistance to the influence of sulfate solution conducted on three kinds of
Portland cement with rather high content of 3CaO-Al2O3 (5.45-11.84 wt %).
Also, the paper considers the resistance of all cements blended with 30 wt. %
of fly ash whose 3CaO-Al2O3 content was almost negligible so as to lower the
3CaO-Al2O3 content of the mixtures to 3.82-8.29 wt %. Experiments were
conducted on a 3x2 series of test samples prepared in accordance with Kind's
method (GOST 4798-69). Then, they were exposed to the influence of aggressive
solutions with 1 and 2 kg m-3 of SO42- ions as well as 0.320
kg m-3 of NH4+ ions. Also, pure water was used as a neutral fluid. The
experiments lasted six months, while flexural strengths were measured after 1,
2, 4 and 6 months. By dividing the flexural strength of corroded samples with
the strength of a referent ones a kind of corrosion resistance factor was
obtained as a numerical quantifier of a sample's quality. The results were
analyzed separately, no-ash samples and ash samples were considered to be two
different systems. The behavior of each (under the influence the influence of
both ions from the solutions in two concentrations) was considered. The samples
with fly ash proved generally more resistant for all concentrations and
duration of the degradation.
Key
words: cement, fly ash containing cement, sulfate corrosion of cement
J. Serb. Chem. Soc. 62(10) 1011-1018 (1997)
JSCS-2468
UDK
546.19:543.062:547..565.3
Original scientific
paper
Catalytic determination of micro amounts of As(III) using its
catalytic effect on the oxidation of sodium pyrogallol-5-sulphonate by
dichromate
S. S. MITIC, V. V. ZIVANOVIC and M. V. OBRADOVIC
Department of Chemistry, Faculty of Philosophy, University of
Nis, YU-18000 Nis, Yugoslavia
(Received
27 November 1996, revised 29 May 1997)
A kinetic method is described for the
determination of As(III) based on its catalytic effect on the oxidation of
sodium pyrogallol-5-sulphonate by Cr2O72-. The reaction was
followed spectrophotometrically by measuring the rate of change in the
absorbance of the colored product at 436.8 nm. Micro amounts of As(III)
(0.375-3.75 µg cm-3) can be determined with good accuracy and reproducibility. The
effects of certain foreign ions upon the reaction rate were determined for the
assessment of the selectivity of the method. The kinetic parameters of both of
the catalyzed and uncatalyzed reactions are reported.
Key
words: As(III) determination, kinetic method, sodium pyrogallol-5-sulphonate
oxidation
J. Serb. Chem. Soc. 62(10) 1019-1024 (1997)
JSCS-2469
UDK
546.19'23'':543.062:533.92
Original
scientific paper
Comparison of two sample introduction techniques for the
determination of arsenic and selenium by direct current are plasma atomic
emission spectrometry DCP-AES
MILOVAN STOILJKOVIC and NEBOJSA PAVLOVIC
The Vinca Institute of Nuclear Science, Department of Physical
Chemistry, P.O.Box 522, YU-11001 Belgrade, Yugoslavia
(Received
3 March 1997)
Nebulization of solution (NS) and batch
mode hydride generation (HG) techniques, followed by direct current arc plasma
atomic emission spectrometry (DCP-AES) were compared for trace arsenic and
selenium determination. Calibration graphs and detection limits (established
for standard solutions) were determined at non-standard wavelengths. About 85
and 65 times lower detection limits for As and Se, respectively, were achieved
with HG than with NS. A hydride generation techniques was then used for the
trace determination of arsenic in white wheat flour and selenium in
commercially available Ferksevit capsules, used as a diet supplement.
Key
words: arsenic, selenium, trace determination, hydride generation technique