JSCS Vol 73, No. 4
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J. Serb. Chem. Soc. 73 (4) 385–391 (2008)
UDC
542.913:546.141+547.262+547.861.3+661.333; JSCS–3720;
doi: 10.2298/JSC0804385M;
Original scientific paper
A green process for the preparation of
11-{4-[2-(2-hydroxyethoxy)ethyl]-1-piperazinyl}dibenzo[b,f][1,4]thiazepine
GANESH D. MAHALE, ASHOK KUMAR*, DHARMENDRA SINGH*, A. V. RAMASWAMY and SURESH
B. WAGHMODE
Department of Chemistry,
*IPCA
Laboratories, Kandivali Industrial Estate Charkop, Kandivali West, Mumbai 400
067, India
(Received 11 July, revised
A green process for the synthesis of
11-{4-[2-(2-hydroxyethoxy)ethyl]-1-piperazinyl}dibenzo[b,f][1,4]thiazepine by the reaction of 11-(1-piperazinyl)dibenzo[b,f][1,4]thiazepine or its
dihydrochloride salt with 2-(2-chloroethoxy)ethanol in the presence of an
inorganic base and water is reported (conversion 99.9 % in a short time and
without any impurities). The metal halides and phase transfer catalyst increase
the rate of reaction, especially in water as the solvent.
Keywords: quetiapine; KI; tetrabutylAMmonium bromide (TBAB);
2-(2-chloroethoxy)ethanol; N,N-dimethylformAMide;
sodium carbonate.
Full Article
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J. Serb. Chem. Soc. 73 (4) 393–403 (2008)
UDC 577.112.383:546.11+544.35:544.4;
JSCS–3721; doi: 10.2298/JSC0804393L;
Original scientific paper
Short hydrogen bonds in the catalytic mechanism of
serine proteases
Faculty of Technology,
*Faculty of Science ,
**Faculty of Agriculture,
(Received 15 May, revised
The survey of crystallographic data from the Protein
Data Bank for 37 structures of trypsin and other serine proteases at a
resolution of 0.78–1.28 Å revealed the presence of hydrogen bonds in the active
site of the enzymes, which are formed between the catalytic histidine and
aspartate residues and are on average 2.7 Å long. This is the typical bond
length for normal hydrogen bonds. The geometric properties of the hydrogen
bonds in the active site indicate that the H atom is not centered between the
heteroatoms of the catalytic histidine and aspartate residues in the active
site. Taken together, these findings exclude the possibility that short
“low-barrier” hydrogen bonds are formed in the ground state structure of the
active sites exAMined in this work. Some time ago, it was suggested by Cleland
that the “low-barrier hydrogen bond” hypothesis is operative in the catalytic
mechanism of serine proteases, and requires the presence of short hydrogen
bonds around 2.4 Å long in the active site, with the H atom centered between
the catalytic heteroatoms. The conclusions drawn from this work do not exclude
the validity of the “low-barrier hydrogen bond” hypothesis at all, but they
merely do not support it in this particular case, with this particular class of
enzymes.
Keywords: trypsin; serine proteases; low-barrier hydrogen
bonds.
Full Article - PDF 349 KB
J. Serb.
Chem. Soc. 73 (4) 405–413 (2008)
UDC
66.061–034:582.293.378:541.132.3+544.35; JSCS–3722; doi: 10.2298/JSC0804405C; Original scientific
paper
Metal extraction from Cetraria islandica (L.) Ach. lichen
using low pH solutions
ANA A. CUCULOVIC, MIRJANA S. PAVLOVIC*, DRAGAN S. VESELINOVIC** and SCEPAN S.
MILJANIC**
INEP – Institute for the Application of Nuclear Energy, Banatska 31b, 11080
Zemun, Serbia
*Institute of Nuclear Science
"Vinca", Department of Physical Chemistry, P. O. Box 522, 11001
Belgrade, Serbia
**University of Belgrade, Faculty of Physical
Chemistry, P. O. Box 137, 11001 Belgrade, Serbia
(Received 24 September, revised 7
November 2007)
Extraction of metals (K, Al, Ca, Mg, Fe,
Cu, Ba, Zn, Mn and Sr) from dry Cetraria
islandica (L.) Ach. lichen was performed using solutions similar to acid
rain (solution A – H2SO4–HNO3–(NH4)2SO4
and solution B – H2SO4–HNO3–(NH4)2SO4–NH4NO3).
The pH values of these solutions were 2.00, 2.58, 2.87, 3.28, and 3.75. Five
consecutive extractions were performed with each solution. In all solutions,
the extracted metal content, except Cu and Ca, was the highest in the first
extract. The highest percentage of the metals desorbed in the first extraction
was obtained using solutions with low pH values, 2.00, 2.58, and 2.87. The
lowest percentage in the first extraction was obtained using solutions with pH
3.28 and 3.75, indicating influence of the H+ ion on the extraction.
According to the results obtained, the investigated metals form two groups. The
first group includes K, Al, Ca, Mg, and Fe. They were extracted in each of the
five extractions at each of the pH values. The second group includes Ba, Zn,
Mn, Cu, and Sr, which were not all extracted at each pH value. The first group
yielded three types of extraction curves when the logarithms of extracted metal
AMounts were plotted as a function of the number of successive extractions.
These effects indicate that three different positions (centres) of metal ion
accumulation exist in the lichen (due to sorption, complex formation, or other
processes present in the tissues).
Keywords:
Cetraria islandica (L.) Ach. lichen; acid rain; extraction; heavy metals.
Full Article - PDF 308 KB
J. Serb. Chem. Soc. 73 (4) 415–421 (2008)
UDC
542.9+547.571+547.551:547.665:547.288.2:615.281; JSCS–3723; doi:
10.2298/JSC0804415S;
Original scientific paper
Biologically active new Fe(II), Co(II),
Ni(II), Cu(II), Zn(II) and Cd(II) complexes of N-(2-thienylmethylene)methanAMine
C. SPÎNU, M. PLENICEANU and C. TIGAE
University of Craiova, Faculty of Chemistry, Department of Inorganic Chemistry,
A. I. Cuza no. 13, Craiova, Romania
(Received 2 April, revised 22 November
2007)
Iron(II), cobalt(II), nickel (II), copper (II),
zinc(II) and cadmium(II) complexes of the type ML2Cl2,
where M is a metal and L is the Schiff base N-(2-thienylmethylene)methanAMine
(TNAM) formed by the condensation of 2-thiophenecarboxaldehyde and methylAMine,
were prepared and characterized by elemental analysis as well as magnetic and
spectroscopic measurements. The elemental analyses suggest the stoichiometry to
be 1:2 (metal:ligand). Magnetic susceptibility data coupled with electronic,
ESR and Mössbauer spectra suggest a distorted octahedral structure for the
Fe(II), Co(II) and Ni(II) complexes, a square-planar geometry for the Cu(II)
compound and a tetrahedral geometry for the Zn(II) and Cd(II) complexes. The
infrared and NMR spectra of the complexes agree with co-ordination to the
central metal atom through nitrogen and sulphur atoms. Conductance measurements
suggest the non-electrolytic nature of the complexes, except for the Cu(II),
Zn(II) and Cd(II) complexes, which are 1:2 electrolytes. The Schiff base and
its metal chelates were screened for their biological activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the metal
chelates were found to possess better antibacterial activity than that of the
uncomplexed Schiff base.
Keywords: Schiff base; 2-thiophenecarboxaldehyde; N-(2-thienylmethylene)methanAMine;
antibacterial activity.
Full Article - PDF 267 KB
UDC
542.9+547.571+547.551:546.742'562'472:547.573:543.422.25 JSCS–3724; doi:
10.2298/JSC0804423K;
Original scientific paper
Metal complexes of Schiff bases derived from
dicinnAMoylmethane and aliphatic diAMines
K.
KRISHNANKUTTY, P. SAYUDEVI* and MUHAMMED BASHEER UMMATHUR**
Department of Chemistry,
*Department of
Chemistry,
**Department of
Chemistry, Unity Women’s College, Manjeri, Kerala-676122,
(Received 26 July, revised
Two new Schiff bases containing olefinic
linkages have been synthesized by condensing aliphatic diAMines with
dicinnAMoylmethane under specified conditions. The existence of these compounds
predominantly in the intrAMolecularly hydrogen bonded keto-enAMine form was
well demonstrated by their IR, 1H-NMR and mass spectral data.
Dibasic tetradentate N2O2 coordination of the compounds
in their [ML] complexes (M = Ni(II), Cu(II) and Zn(II)) was established on the
basis of analytical and spectral data.
Keywords: Schiff base; dicinnAMoylmethane; metal complexes;
IR spectra; 1H-NMR spectra; mass spectra.
Full Article - PDF 263 KB
J. Serb. Chem. Soc. 73 (4) 431–433 (2008)
UDC 519.17+544.112:533.73:539.124; JSCS–3725; doi:
10.2298/JSC0804431F; Note
NOTE
Bicyclic molecular graphs with the greatest energy
BORIS FURTULA, SLAVKO RADENKOVIC and IVAN GUTMAN
Faculty of Science,
(Received
The molecular graph Qn is obtained by attaching hexagons to the end vertices
of the path graph Pn-12.
Earlier empirical studies indicated that Qn
has greatest energy AMong all bicyclic n-vertex
(molecular) graphs. Recently, Li and Zhang proved that Qn has greatest energy AMong all bipartite bicyclic
graphs, with the exception of the graphs Ra,b,
a + b = n, where Ra,b is the graph obtained by
joining the cycles Ca and
Cb by an edge. This result
is now completed by showing that Qn has the greatest energy AMong
all bipartite bicyclic n-vertex
graphs.
Keywords: total π-electron energy; graph energy;
bicyclic molecular graphs.
Full Article - PDF 334 KB
J. Serb. Chem. Soc. 73 (4) 435–451 (2008)
UDC
66.061.35:546.683.3+547.412.123:544.032.4; JSCS–3726; doi: 10.2298/JSC0804435M; Original scientific paper
Rapid liquid–liquid extraction of
thallium(III) from succinate media with 2-octylAMinopyridine in chloroform as
the extractant
SANDIP V.
MAHAMUNI, PRAKASH P. WADGAONKAR* and MANSING A. ANUSE
Analytical
Chemistry Laboratory, Department of Chemistry,
*Polymer Science
and Engineering Division, National Chemical Laboratory,
(Received
A simple solvent extraction study of
thallium(III) was conducted. Selective and quantitative extraction of
thallium(III) by 2-octylAMinopyridine (2-OAP) in chloroform occurred from
aqueous sodium succinate medium (0.0075 M) at pH 3.0. Thallium(III) was back
extracted with acetate buffer (pH 4.63). The effect of the concentration of
succinate and 2-OAP, the role of various diluents, stripping agents, loading
capacity of 2-OAP, equilibrium time and aqueous:organic volume ratio on the
extraction of thallium(III) was studied. The stoichiometry of the extracted
species was determined based on the slope analysis method and found to be 1: 2:
1 (metal:acid:extractant). The temperature dependence of the extraction
equilibrium constant was also exAMined to estimate the apparent thermodynAMic
functions ∆H, ∆G and ∆S for the extraction reaction. The method is free from
interference of a large number of cations and anions. The method was used for
the selective extraction of thallium(III) from its binary mixture with Zn(II),
Cd(II), Hg(II), Bi(III), Pb(II), Se(IV), Te(IV), Sb(III), Ga(III), In(III),
Al(III), Tl(I) and Fe(III). The proposed method was applied to the synthetic
mixtures and alloys. It is simple, selective, rapid and eco-friendly.
Keywords: liquid–liquid extraction; thallium(III); succinate
media; 2-OAP; temperature effect.
Full Article - PDF 298 KB
J. Serb. Chem. Soc. 73 (4)
453–461 (2008)
UDC
550.4:543+546.47+546.815+546.65:597+631.442.4'2; JSCS–3727; doi:
10.2298/JSC0804453P; Original scientific paper
Cretaceous – Paleogene
boundary Fish Clay at Højerup (
Laboratory for
Geochemistry, Cosmochemistry and Astrochemistry,
*Institute of Nuclear
Sciences Vinca, P. O. Box 522, 11001
(Received 28 May, revised
29 June 2007)
Geochemical analyses of Zn,
Pb and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in the kerogen
of the black marl at the Cretaceous –
Paleogene boundary Fish Clay at Højerup were performed. Substantial
proportions of the Zn, Pb and rare earths were probably contained in
terrestrial humic substances (the kerogen precursor) arriving at the marine
sedimentary site. This is in accord with a previous hypothesis that kerogen is
mainly derived from humic acids of an oxic soil in of the adjacent coastal
areas of eastern Denmark. It is also suggested that humics enriched in Zn, Pb
and rare earth elements were transported mainly through fluvial transport into
the deposition site of the Fish Clay. Local weathering/leaching of the
impact–eject fallout on the land surface and local terrestrial rocks by
impact-induced? acid surface waters perhaps played an important role in
providing Zn, Pb and rare earths to these humic substances. Apparently,
chondritic and non-chondritic Zn originated from the impact fallout; Pb and
rare earth elements were most likely sourced by exposed rocks in the coastal
areas of eastern Denmark.
Keywords: geochemistry; Cretaceous – Paleogene boundary;
zink; lead; rare earth elements; kerogen.
Full Article - PDF 532 KB
J. Serb. Chem. Soc. 73 (4)
463–478 (2008)
UDC 546.717–36+542.92:662.67:678.094.3; JSCS–3728, doi:
10.2298/JSC0804463B; Original scientific paper
Characterization of type
III kerogen from Tyrolean shale (Hahntennjoch, Austria) based on its oxidation
products
S. BAJC, O. CVETKOVIC, A.
AMBLÈS* and D. VITOROVIC
Center of Chemistry,
Institute of Chemistry, Technology and Metallurgy, Njegoseva 12, 11000
Belgrade, Serbia
*Department of Chemistry,
Faculty of Science, University of Poitiers, 40, Av. du Recteur Pineau, 86022
Poitiers, France
(Received 15 October,
revised 19 November 2007)
A 29-step alkaline
permanganate degradation of type III kerogen from Tyrolean (Hahntennjoch,
Austria) oil shale was performed. A high yield of oxidation products was
obtained (93.7 % relative to the original kerogen): 0.5 % neutrals and bases,
19.5 % ether-soluble acids and 58.9 % of precipitated (PA). A substantial
AMount of kerogen carbon (14.8 %) was oxidized into carbon dioxide. The organic
residue remaining after the final oxidation step was 6.9 %. The PA components
were further oxidized and the total yields relative to original PA were 1.0 %
neutrals and bases and 59.0 % ether-soluble acids, the non-degraded residue
being 29.3 %. Detailed quantitative and qualitative analysis of all oxidation
products suggested the Tyrolean shale kerogen to be a heterogeneous
macromolecular substance consisting of three types of structures differing in
composition and susceptibility towards alkaline permanganate: the first,
resistant, presumably composed of aromatic structures linked by resorcinol
ethereal bonds; the second, combined in nature, the aliphatic part comprising
methyl-substituents and short cross-links, both easily oxidized into CO2, water
and low molecular weight acids and aromatic structures yielding aromatic di-
and tri-carboxylic acids as oxidation products; finally the third, composed of
aliphatic cross-links and substituents, alicyclic (and/or heterocyclic) and
some aromatic structures, bound into units moderately resistant towards
oxidation. The overall yields of kerogen and PA oxidation products lead towards
a balance between aromatic, alkane mono- and dicarboxylic and
alkanepolycarboxylic acids, suggesting a shift of the structure of Tyrolean
shale kerogen from typical aromatic reference type III towards a heterogeneous aromatic-aliphatic-alicyclic
type structure.
Keywords: Tyrolean shale; type III kerogen; structural
characterization; alkaline permanganate degradation; oxidation products.
Full Article - PDF 778 KB
J. Serb. Chem. Soc. 73 (4)
479–486 (2008)
UDC 546.654.027*123+544.773.42:542.913.004.12:621.315;
JSCS–3729; doi: 10.2298/JSC0804479Z; Original scientific paper
Synthesis and
characterization of Ln-123 superconductors
ARTURAS ZALGA, REMIGIJUS
JUSKENAS*, ALGIRDAS SELSKIS*, DARIUS JASAITIS and AIVARAS KAREIVA
Faculty of Chemistry,
Vilnius University, Naugarduko 24, LT-03225
*Institute of Chemistry, A.
Gostauto 9, LT-01108
(Received 10 January,
revised 12 November 2007)
A sol–gel method was applied
to prepare precursors for NdBa2Cu3O7-x
(Nd-123) and SmBa2Cu3O7-x (Sm-123)
superconducting compounds. The sintered products were exAMined by X-ray
diffraction analysis (XRD) and scanning electron microscopy (SEM). The powders
sintered at 950 and 1000 °C showed the formation of monophasic Nd-123 and
Sm-123 superconductors. The formation of Nd-123 and Sm-123 phases from the
sol-gel derived precursors at higher temperatures (1050 and 1100 °C), however,
did not proceed due to the melting process. The correlation between the TC
for different lanthanides (Ln – Ho, Nd and Sm) in the Ln-123 compound and
orthorhombicity and oxygen stoichiometry were also estimated.
Keywords: 123 superconductors; substitution effects;
lanthanides; sol–gel synthesis.
Full Article - PDF 789 KB
J. Serb. Chem. Soc. 73 (4)
487–497 (2008)
UDC
66.011+519.22:54–32:546.46–31:66.061; JSCS–3730; doi: 10.2298/JSC0804487R; Original
scientific paper
Process
improvement approach to the acid activation of smectite using factorial and
orthogonal central composite design methods
LJILJANA ROZIC, TATJANA
NOVAKOVIC and SRDJAN PETROVIC
ICTM – Department of Catalysis
and Chemical Engineering, Njegoseva 12,
(Received 4 September,
revised 23 November 2007)
The purpose of this study
was to determine the effective operating parAMeters and the optimum operating
conditions of an acid activation process within the frAMework of improvement of
the process. Full two-level factorial and orthogonal central composite design
methods were used successively. The exAMined parAMeters were the main and
interaction effects of temperature, leaching time, acid normality,
solid-to-liquid ratio and stirring rate. The selected process response was the
leaching yield of the MgO content because Mg is the element most readily
removed from the octahedral sheet, which affects the tendency for activation.
Statistical regression analysis and analysis of variance were applied to the
experimental data to develop a predictive model, which revealed that
temperature, leaching time and acid normality exert the strongest influence on
the specific surface area of smectite, whilst the solid-to-liquid ratio and the
stirring rate have a secondary effect. Furthermore, the highest leaching yield
of MgO was found to be 41.86 %, which is responsible for the increase in the
specific surface area of up to 221 m2 g-1.
Keywords: statistical modeling; acid activated smectite;
leaching of MgO; specific surface area.
Full Article - PDF 320 KB
J. Serb. Chem. Soc. 73 (4)
499–506 (2008)
UDC
536.7.001.2:546.82’62’711:681.3.06:536.7; JSCS–3731; doi:
10.2298/JSC0804499K; Original scientific paper
ThermodynAMic calculations
in ternary titanium–aluminium–manganese system
ANA I. KOSTOV and DRAGANA T. ZIVKOVIC*
Copper Institute Bor, Zeleni bulevar 35, 19210
Bor, Serbia
*University of Belgrade, Technical Faculty Bor,
VJ 12, 19210 Bor, Serbia
(Received 24 May, revised
15 October 2007)
ThermodynAMic calculations
in the ternary Ti–Al–Mn system are shown in this paper. The thermodynAMic
calculations were performed using the FactSage thermochemical software and
database, with the aim of determining thermodynAMic properties, such as
activities, coefficient of activities, partial and integral values of the
enthalpies and Gibbs energies of mixing and excess energies at two different
temperatures: 2000 and 2100 K. Bearing in mind that no experimental data for
the Ti–Al–Mn ternary system have been obtained or reported. The obtained
results represent a good base for further thermodynAMic analysis and may be
useful as a comparison with some future critical experimental results and
thermodynAMic optimization of this system.
Keywords: thermodynAMic calculations; Ti–Al–Mn ternary
system; FactSage thermochemical software and database.
Full Article - PDF 952 KB
J. Serb. Chem.
Soc. 73 (4) 507–512 (2008)
UDC 543+061.3(4); JSCS–3731;
EuCheMS news
European analytical column
No. 36 from the Division of Analytical Chemistry (DAC) of the European
Association for Chemical and Molecular Sciences (EuCheMS)
BO KARLBERG, HENDRIK EMONS* and JENS E. T.
ANDERSEN**
Department of Analytical
Chemistry, Stockholm University, SE-10691
*Institute for Reference
Materials and Measurements (IRMM), Joint Research Centre, European Commission,
B-2440
**Department of Chemistry,
Technical University of Denmark, Building 207, DK-2800 Lyngby
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Copyright
&AMp; copy; SHD 2008.
April 14, 2008.
For more information contact: JSCS@tmf.bg.ac.yu