JSCS Vol 67, No. 10
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Impresum |
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J.
Serb. Chem. Soc. 67 (10)639–646(2002) |
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SHORT COMMUNICATION
Chemical
composition and antimicrobial action of the ethanol extracts of
Salvia pratensis L., Salvia glutinosa L. and Salvia
aethiopis L.
DRAGAN T. VELICKOVIC, NOVICA V. RANDJELOVIC*, MIHAILO S. RISTIC**,
ANDRIJA A. SMELCEROVIC*** and ANA S. VELICKOVIC****
AD “Zdravlje” Pharmaceutical and
Chemical Industry, Vlajkova St. 199, YU-16000 Leskovac,
*Faculty of Technology, Bulevar Oslobodjenja St. 124, YU-16000
Leskovac,
**Institue for Medicinal Plants Research “Dr. Josif Pancic”,
Tadeusa Koscuska St. 1, YU-11000 Belgrade,
***Chemical Industry “Nevena”, Djordja Stamenkovica St. bb., YU-16000
Leskovac, and
****Medical Center “Mosa Pijade”, Department of General Practice,
Rade Koncara St. 2, YU-16000 Leskovac, Yugoslavia
(Received
1 April, revised 27 May 2002)
Abstract:
In this paper the chemical composition and antimicrobial action of the extracts
from the flower, leaf and stem of Salvia pratensis L., Salvia
glutinosa L. and Salvia aethiopis L. were investigated. The
investigated extracts mostly contain monoterpenes to a high degree, except the
flower extract of S. pratensis and the leaf extract of S. glutinosa
where sesquiterpenes were found in great amounts. Diterpenes were found only in
the extracts of S. aethiopis. All these extracts contained 1,8-cineole
(to the highest degree (19.1 %) in the stem extract of S. glutinosa) and
beta-caryophyllene (to the highest degree (7.0 %) in the flower extract of S.
pratensis). The antimicrobial activities of the extracts were determined by
the diffusion and dilution method.
Keywords:
Salvia pratensis, Salvia glutinosa, Salvia aethiopis, Lamiaceae, extracts,
chemical composition, antimicrobial activity.
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J.
Serb. Chem. Soc. 67 (10)647–651(2002) |
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Upgrading the Wiener index
EDUARDO A. CASTRO, IVAN GUTMAN*, DAMIAN MARINO and PABLO PERUZZO
CEQUINOR, Departamento de Quimica,
Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C. C. 962, La
Plata 1900, Argentina and
*Faculty of Science, University of Kragujevac, P. O. Box 60,
YU-34000 Kragujevac, Yugoslavia
(Received
18 June 2002)
The
Wiener index W is the oldest molecular-graph-based structure-descriptor. It is
defined as the sum of the distances of all pairs of vertices of the molecular
graph G, where the distance is the number of edges in the shortest path
connecting the respective vertices, and where G is the hydrogen-depleted
molecular graph. This seemingly very simple topological index could be
"upgraded" (a) by using as the distance the sum of the bond
lengths along the shortest path, or (b) by using the Euclidean distance
between the respective pairs of atoms. Each of these "upgraded"
Wiener indices could be computed either (a) for the hydrogen-depleted or
(b) for the hydrogen-filled molecular graph. We provide examples showing
that none of the modifications (aa), (ab), (ba), (bb) yields
better results than the ordinary Wiener index, and that there is a very good
linear correlation between W and its "upgraded" variants.
Keywords:
Wiener index, topological index, 3D-structure descriptors, chemical graph
theory, QSPR, QSAR.
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J. Serb. Chem.
Soc. 67(10)653–659(2002) |
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Extraction of Tb(III) with N,N,N’,N’-tetrabutylmalonamide
SUN GUOXIN, CUI YU**, JIANG RUNTIAN, XU RONGQI and SUN SIXIU**
Institute of Chemistry and
Environmental Engineering, Jinan University, Jinan, 250022, P. R. China,
*Institute of Chemical Engineering, Jinan University, Jinan,
250022, P. R. China, and
**Institute of Chemistry, Shandong University, Jinan, 250100, P.
R. China
(Received
15 April, revised 25 June 2002)
The
study on the extraction and separation of rare earths with new extractants is
important in rare earth hydrometallurgy and nuclear fuel reprocessing. In this
work, a new synthesis method of N,N,N’,N’-tetrabutylmalonamide (TBMA) is
described with a yield higher than 80 %. The extraction behavior of TBMA
employing n-hexane-20 % n-octanol, benzene and toluene as diluents
toward Tb(III) was investigated. The effect of the concentrations of nitric
acid, lithium nitrate and extractant as well as the temperature on the
extraction distribution ratio was studied in different diluents. The
stoichiometry of the extracted species of Tb(III) conforms to Tb(NO3)3·3TBMA. An
attempt was made to determine the structure of the extracted species from IR
and mol conductance data.
Keywords:
synthesis, N,N,N’,N’-tetrabutylmalonamide, extraction, Tb(III), diluent,
structure.
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J.
Serb. Chem. Soc. 67(10)661–667(2002) |
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A kinetic method for the
determination of phenol
SNEZANA S. MITIC and VALENTINA V. ZIVANOVIC
Faculty of Sciences and
Mathematics, Department of Chemistry, University of Nis, Visegradska 33,
P.O.Box 224, YU-18000 Nis, Yugoslavia
(Received
21 March 2001, Revised 1 July 2002)
A
kinetic method for the determination of phenol is proposed. The method is based
on the inhibiting effect of phenol on the Mn(II) catalysis of the oxidation of
malachite green with potassium periodate. The reaction rate was followed
spectrophotometrically at 615 nm. Kinetic expression for the reaction in the
presence and absence of phenol are postulated. The optimal experimental
conditions for the determination of phenol were established and phenol was
determined in concentrations from 30.0 to 188.0 ng/cm3 with a
relative standard deviation of 5.5 %. The lower detecton limit is 7.8 ng/cm3. The
effects of certain foreign ions upon the reaction rate were determined for the
assessment of the selectivity of the method. The method was applied for the
determination of phenol in tap and river water.
Keywords:
phenol kinetic determination, malachite green oxidation, potassium periodate.
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J. Serb. Chem.
Soc. 67(10)669–676(2002) |
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Spectrophotometric determination of
trace iron(III) in natural water after its preconcentration with a chelating
resin
ZENOVIA MOLDOVAN and ELEONORA-ANA NEAGU*
University of Bucharest, Faculty of
Chemistry, Department of Analytical Chemistry, 4-12 Regina Elisabeta Blvd.,
703461-Bucharest, Romania and
*Institute of Rare and Nonferrous Metals, 102 Biruintei Blvd.,
Bucharest, Romania
(Received
2 February, revised 17 May 2002)
A
method for the determination of Fe(III) at trace levels is described. Thus,
prior to the spectrophotometric determination, a preconcentration of the trace
amounts of iron(III) using a chelate forming resin is proposed. A strong base
anion-exchange resin (Dowex 2X4) loaded with Ferron
(7-iodo-8-hydroxyquinoline-5-sulphonic acid) was used for Fe(III)
preconcentration, at pH 2.2. After desorption with 5 % ascorbic acid in 0.5 M
HCl, the analyte (converted from Fe(III) to Fe(II) was determined
spectrophotometrically at 510 nm as Fe(II)-o-phenanthroline complex. The
accuracy of the proposed method was verified by comparing the obtained results
with those obtained using AAS with the standard addition method. The
sensitivity of the spectrophotometric method (after preconcentration) was 0.01 mg
Fe(III)/ml. The recovery for iron(III) at the 7 mg/l level was 97 %.
Keywords:
iron(III), Ferron, chelating resin, preconcentration, spectrophotometric
determination.
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J. Serb. Chem.
Soc. 67(10)677–684(2002) |
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Cu(II) complexes with a pendant
octaazamacrocycle and m-bonded aromatic carboxylates
GORDANA VUCKOVIC, MIRJANA ANTONIJEVIC* and DEJAN POLETI**
Faculty of Chemistry, University of
Belgrade, P. O. Box 158, YU-11001 Belgrade
*High School for Chemistry and Technology, YU-15000 Sabac and
**Department of General and Inorganic Chemistry, Faculty of
Technology and Metallurgy, Karnegijeva, 4, YU-11000 Belgrade, Yugoslavia
(Received
20 March 2002)
Three
new cationic mixed-ligand Cu(II) complexes with N,N’,N’’,N’’’-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane
(tpmc) and bridging aromatic mono- or dicarboxylate ligands were prepared.
Elemental analysis, conductometric and magnetic measurements, as well as
electronic and IR spectroscopy were employed for their characteriization. It is
proposed that the complexes [Cu2(C6H5COO)tpmc](CIO4)3MeOH and
[Cu2(Hpht)tpmc](CIO4)3H2O (H2pht =
phthalic acid) are binuclear with m-coordination of the carboxylate
monoanions. The third complex, [Cu4ipht(tpmc)2](CIO4)6NaClO42MeCN (H2ipht =
isophthalic acid) is one of the rare tetranuclear Cu(II)-tpmc complexes with an
aromatic dicarboxylate ion bridging two Cu2tpmc units. This was also confirmed
by preliminary results of the determination of the crystal structure.
Keywords:
copper(II) complexes, octaazamacrocycle, benzoate, phthalate, isophthalate.
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J. Serb. Chem.
Soc. 67(10)685–696(2002) |
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Study of the ability of
self-assembled N-vinylcarbazole monolayers to protect copper against
corrosion
CHUN-TAO WANG*, SHEN-HAO CHEN*,**, HOU-YI MA*, LAN HUA*
and NAI-XING WANG*
*Department of Chemistry, Shandong
University, Jinan 250100, P. R. China and
**State Key Laboratory for Corrosion and Protection, Shenyang
110015, P. R. China
(Received
17 January, revised 28 June 2002)
N-Vinylcarbazole (NVC) monolayers were self-assembled on copper
surfaces. The electrochemical properties of the copper surfaces modified by NVC
self-assembled monolayers (SAMs) were investigated using polarization and
electrochemical impedance spectroscopic (EIS) methods. The polarization
measurements indicated that the NVC SAMs could reduce the rates of the anodic
and cathodic reaction on the surface of copper electrodes in 0.5 mol dm-3 NaCl
solution. The EIS results showed the NVC formed a closely packed film that was
able to inhibit copper corrosion. X-Ray photoelectron spectroscopy (XPS)
analysis of the copper samples and atomic adsorption analysis of the solution
showed that the copper surfaces were covered by NVC SAMs, and the adsorption of
NVC on the copper surfaces was accompanied with dissolution of Cu into the
solution.
Keywords:
self-assembled monolayers, N-vinylcarbazole, copper, EIS, XPS.
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J. Serb. Chem.
Soc. 67(10)697–707(2002) |
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The effect of boron on the amount
and type of carbides in chromium white irons
STANKA M. TOMOVIC-PETROVIC, SRDJAN V. MARKOVIC* and SLAVICA ZEC**
Institute “Kirilo Savic”, Vojvode
Stepe 51, YU-11000 Belgrade,
*Faculty of Technology and Metallurgy, University of Belgrade,
Karnegijeva 4, YU-11000 Belgrade and
**Vinca Institute for Nuclear Science, P. O. Box 522, YU-11000
Belgrade, Yugoslavia
(Received
23 August 2000, revised 15 June 2002)
The
effect of boron, in the amounts of 0.26, 0.39, and 0.59 wt.%, on the volume
fraction and structure of carbides in Cr white irons was examined. It was
demonstrated that the addition of boron can change the microstructural
characteristics of white iron containing about 13 wt.% Cr. With increasing
boron content, the volume fractions of M3C carbide
increase, but the volume fracton of M7C3 carbide
remains unchanged. The addition of boron tends to produce hard borides and/or
borocarbides. It also prevents the formation of pearlite, which results in
alloys possessing good wear resistance.
Keywords:
chromium white iron, boron, carbides, borocarbide.
Copyright & copy; SHD 2002.
Last
Updated October 5, 2002.
For
more information contact: SHD@elab.tmf.bg.ac.yu