JSCS Vol 67, No. 4
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.
67(4)221-227(2002) |
To download this article click here 97 KB |
A model study of epothilone
synthesis: an alternative synthetic approach to the C1–C7 fragment
GOJKO LALIC, DANICA GALONIC, RADOMIR MATOVIC and RADOMIR N. SAICIC
Faculty of Chemistry, University of
Belgrade, Studentski trg 16, P.O. Box 158, YU-11000 Belgrade and
Institute of Chemistry, Technology and Metallurgy-Center for
Chemistry, Njegoseva 12, YU-11001 Belgrade, Yugoslavia
(Received
25 September 2001)
In
this model study an alternative synthetic approach to the C1–C7 fragment of
epothilones was investigated. Starting from 4,4-dimethylcyclopentenone, a 7
step reaction sequence afforded the key intermediate 7 in 27 % overall yield.
Surprisingly, the attempted deprotection of latent functionalities in 7 failed,
indicating the incompatibility of the ethoxyethyl protective group with the
reaction conditions employed.
Keywords:
epothilones, epoxides, enol ethers, alkylations, Lewis acids.
|
J.Serb.Chem.Soc.
67(4)229–234(2002) |
To download this article click here 74 KB |
Mixed ligand complexes of alkaline
earth metals: Part XII. Mg(II), Ca(II), Sr(II) and Ba(II) complexes with
5-chlorosalicylaldehyde and salicylaldehyde or hydroxyaromatic ketones
R. N. PRASAD, MITHLESH AGRAWAL and MADHULIKA SHARMA
Department of Chemistry, University
of Rajasthan, Jaipur – 302004, India
(Received
9 August 2001)
The
reactions of alkaline earth metal chlorides with 5-chlorosalicylaldehyde and
salicylaldehyde, 2-hydroxyacetophenone or 2-hydroxypropiophenone have been
carried out in 1 : 1 : 1 mole ratio and the mixed ligand complexes of the type
MLL’(H2O)2 (where M = Mg(II), Ca(II), Sr(II) and Ba(II), HL =
5-chlorosalicylaldehyde and HL’ = salicylaldehyde, 2-hydroxyacetophenone or
2-hydroxypropiophenone) have been isolated. These complexes were characterized
by TLC, conductance measurements, IR and 1H-NMR
spectra.
Keywords:
mixed ligand complexes, alkaline earth metals.
|
J.Serb.Shem.Soc.
67(4)235–241(2002) |
To download this article click here 94 KB |
The synthesis and characterization
of facial and meridional isomers of uns-cis-(ethylenediamine-N-N’-di-3-propionato)
cobalt(III) complexes with S-lysine and S-histidine
DANIJELA D. STAMENOVIC and SRECKO R. TRIFUNOVIC
Department of Chemistry, Faculty of
Science, University of Kragujevac, P. O. Box 60, 34000 Kragujevac, Yugoslavia
(Received
14 November 2001)
In
the reaction of sodium uns-cis-(ethylenediamine-N-N’-di-3-propionato)-(carbonato)cobaltate(III)
dihydrate and the corresponding amino acid (S-lysine or S-histidine)
at 70"C, both the theoretically possible facial and meridional isomers of
the uns-cis-(ethylenediamine-N-N’-di-3-propionato)(aminoacidato)cobalt(III)
complexes were prepared. The complexes were isolated chromatographically and
characterized by elemental analyses, as well as by electron absorption and
infrared spectroscopy.
Keywords:
cobalt(III) complexes, ethylenediamine-N-N’-di-3-propionato ligand,
S-lysine, S-histidine.
|
J.Serb.Chem.Soc.
67(4)243–256(2002) |
To download this article click here 129 KB |
Thermodynamics of complexation of
isatin-3-thiosemicarbazone (HIT) and other related derivatives with some metal
ions
H. S. M. SELEEM*, M. EL-BEHAIRY, M. M. MASHALY and H. H. MENA
Chemistry Department, Faculty of
Education, Ain Shams University, Roxy, Cairo, Egypt
(Received
12 September, revised 6 December 2001)
Proton-ligand
formation constants of isatin-3-thiosemicarbazone (HIT) ; N-acetylisatin-3-thiosemicarbazone
(HAIT) and 5-(p-nitrobenzoyl)-1,2,4-triazino[5,6-b]indole-3-thione
(HBITr) ligands and their corresponding metal-ligand formation constants with
Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, UO22+ and Th2+ ions were determined pH-metrically at 10, 20, 30 and 40°C in 75
%(v/v) ethanol–water. The thermodynamic parameters (DG, DH and DS) were also
evaluated. It was found that both log K1 and –DH1, for HIT
and HAIT-complexes are somewhat larger than log K2and –DH2,
indicating a change in the dentate character of these ligands from tridentate
(ONN-donors) in 1:1 chelates to bidentate (ON-donors) in 1:2; M:L chelates. In
contrast, the values of log K2 and – DH2 for
HBITr-complexes are somewhat larger than log K1 and –DH1,
indicating a strong trans-effect for the second coordination. The
dissociation process is non-spontaneous, endothermic and entropically
unfavourable while the complexation process is spontaneous, exothermic and
entropically favourable. The thermodynamic parameters were separated into their
electrostatic (el) and non-electrostatic (non) constituents.
Keywords:
dissociation, stability constants, thermodynamic parameters,
isatin-3-thiosemicarbazone, N-acetylisatin-3-thiosemicarbazone,
5-(p-nitrobenzoyl)-1,2,4-triazino[5,6-b]indole-3-thione.
|
J.Serb.Chem.Soc.
67(4)257–264(2002) |
To download this article click here 95 KB |
Heats of formation for the azine
series: A Gaussian-3 study
MEI-FUN CHENG, HO-ON HO, CHOW-SHING LAM and WAI-KEE LI
Department of Chemistry, The
Chinese University of Hong Kong, Shatin, N.T., Hong Kong
(Received
28 November 2001)
Applying
the Gaussian-3 (G3) model and its variant G3(MP2), and using the atomization
scheme, the heats of formation (DHf) at 0 K
and 298 K have been calculated for twelve monocyclic azines with the general
formula Nn(CH)6-n,n = 1, 2, …, 6. Upon comparing the calculated results with
available experimental data, it is found that the calculated structural
parameters agree very well with the experimental ones. Additionally, most of
the calculated DHf values are well within ±10 kJ mol-1 of the
available experimental data. Thus, it is concluded that the unfavorable
accumulation of component errors found in the Gaussian-2 methods is greatly
reduced in the G3 models. Also, the calculated DHf values for
those azines for which no experimental data exists should be reliable
estimates.
Keywords:
azines, heats of formation, Gaussian-3 calculation.
|
J.Serb.Chem.Soc.
67(4)265–272(2002) |
To download this article click here 92 KB |
Solvent extraction of Sc(III) from
sulfuric acid solution by bis (2-ethylhexyl) phosphinic acid in toluene
DEVENDRA V. KOLADKAR and PURSHOTTAM M. DHADKE
Inorganic Chemistry Laboratory,
Department of Chemical Technology, University of Mumbai, Matunga, Mumbai
400019, India
(Received
2 July, revised 30 October 2001)
Liquid-liquid
extraction of scandium(III) from sulfuric acid solution using bis(2-ethylhexyl)
phosphinic acid (PIA-8) in toluene has been studied. The extraction of
scandium(III) was found to be quantitative with 0.03 M PIA-8 in toluene in the
acidic range of 0.1–0.5 M and 6.0–8.0 M H2SO4. The
effect of the reagent concentration and other parameters on the extraction of
scandium(III) was also studied. The stoichiometry of the extracted species of
scandium(III) was determined on the basis of the slope analysis method. The extraction
reaction proceeds via the cation exchange mechanism in the H2SO4
concentration range of 0.1–0.5 M and the extracted species is ScR3.3HR.
However, at higher acidity (6.0 M –8.0 M H2SO4) it
proceeds by solvation. The extracted species is HSc(SO4)2.4HR. The
temperature dependencies of the extraction equilibrium constants were examined
to estimate the apparent thermodynamic functions (DH, DS and DG) for the
extraction reaction.
Keywords:
scandium(III), solvent extraction, bis(2-ethylhexyl) phosphinic acid,
sulfate.
|
J.Serb.Chem.Soc.
67(4)273–278(2002) |
To download this article click here 90 KB |
The current distribution in an
electrochemical cell. Part VII.Concuding remarks
K. I. POPOV, S. M. PESIC* and P. M. ZIVKOVIC
Faculty of Technology and
Metallurgy, University of Belgrade, P. O. Box 35-03, Karnegijeva 4, YU-11001
Belgrade and
*EI-stampana kola d.d., Printed Circuit Board Factory, Bul. Cara
Konstantina 80-84, YU-18000 Nis, Yugoslavia
(Received
25 July, revised 1 November 2001)
A
new method for the determination of the ability of an electrolyte to distrubute
uniformly current density in an electrochemical cell is proposed. It is based
on the comparison of the current in cells in which the electrode edges touch
the cell side walls with the current in cells with different electrode edge –
cell side wall distances. The effects of cell geometry, process parameters and
current density are discussed and illustrated using the results presented in
the previous papers from this series.
Keywords:
metal electrodeposition, electrochemical cell, current distrubution.
|
J.Serb.Chem.Soc.
67(4)279-289(2002) |
To download this article click here 136 KB |
The growth and optical properties
of Bi12SiO20 single crystals
ALEKSANDAR GOLUBOVIC, SLOBODANKA NIKOLIC, RADOS GAJIC, STEVAN
DJURIC* and ANDREJA VALCIC**
Institute of Physics, Pregrevica
118, P. O. Box 57, YU-11001 Belgrade,
*Faculty of Mining and Geology, Djusina 7, P. O. Box 162, YU-11000
Belgrade and
**Faculty of Technology and Metallurgy, Karnegijeva 4, YU-11000
Belgrade, Yugoslavia
(Received
11 May 2001)
Single
crystals of Bi12SiO20 were grown from the melt by the Czochralski technique. The critical
crystal diameter dc = 10 mm and the critical rate of
rotation wc = 20 rpm
were calculated by equations from the hydrodynamics of a melt. The rate of
crystal growth was experimentally obtained to be 5 mm/h. The crystal growth was
in the [ 111] direction. The lattice parameter a = 1.0096 nm was
determined by X-ray powder diffraction. The reflectance spectra were recorded
in the wave numbers range 20–5000 cm-1 at
different temperatures. For all the recorded spectra the values of the
vibrational TO and LO modes were found using the Kramers-Kronig analysis (KKA).
Twentyfive TO and LO modes were found at 70 K, and eighteen at 295 K. The
obtained results are discussed and compared with published data.
Keywords:
bismuth silicon oxide single crystals, Czochralski technique, critical
diameter, critical rate of rotation, optical properties.
|
J.Serb.Chem.Soc.
67(4)291–300(2002) |
To download this article click here 105 KB |
The growth of Nd: YAG single
crystals
ALEKSANDAR GOLUBOVIC, SLOBODANKA NIKOLIC, RADOS GAJIC, STEVAN DJURIC*
and ANDREJA VALCIC**
Institute of Physics, Pregrevica
118, P. O. Box 57, YU-11001 Belgrade,
*Faculty of Mining and Geology, Djusina 7, P. O. Box 162, YU-11000
Belgrade and
**Faculty of Technology and Metallurgy, Karnegijeva 4, YU-11000
Belgrade, Yugoslavia
(Received
17 October, revised 17 December 2001)
Y3Al5O12 doped with
0.8 % wt. Nd (Nd:YAG) single crystals were grown by the Czochralski technique
under an argon atmosphere. The conditions for growing the Nd: YAG single
crystals were calculated by using a combination of Reynolds and Grashof
numbers. The critical crystal diameter and the critical rate of rotation were
calculated from the hydrodynamics of the melt. The crystal diameter Dc = 1.5 cm
remained constant during the crystal growth, while the critical rate of
rotation changed from wc = 38 rpm after necking to wc = 13 rpm
at the end of the crystal. The value of the rate of crystal growth was
experimentally found to be 0.8–1.0 mm/h. According to our previous experiments,
it was confirmed that 20 min exposure to conc. H3PO4 at 603 K
was suitable for chemical polishing. Also, one-hour exposure to conc. H3PO4 at 493 K
was found to be suitable for etching. The lattice parameter a = 1.201
(1) nm was determined by X-ray powder diffraction. The obtained results are
discussed and compared with published data.
Keywords:
Czochralski technique, Nd:YAG, growth, single crystal, etching.
|
To download this article click here 27 KB |
In memoriam: Professor Ernest B.
Yeager
Ernest
B. Yeager, the Frank Hovorka Professor of Chemistry at Case Western Reserve
University, Cleveland, Ohio, USA, died on March 8, 2002. Prof. Yeager was an
Honorary Member of the Serbian Chemical Society and a Member of the Editorial
Board of this journal.
To
keep the memory of Professor Yeager's colossal contribution to electrochemistry
and physical acoustics it is not necessary to dwell long on nearly 50 years of
teaching at the Case Western Reserve University, advising 80 PhD thesis and 45
postdoctoral fellowships (domestic and international), 270 scientific papers
and 20 books edited or co-edited.
Ernest
B. Yeager graduated summa cum laude with his B.A. degree from Montclair State
University in 1945. He enrolled as a graduate student in chemistry at Western
Reserve University in 1945. After earning his Ph.D. in 1948, he joined the
Department of Chemistry of the Case Western Reserve University, where he served
until his retirement in 1990. He became a full professor in 1958.
Prof.
Yeager founded the Case Center of Electrochemical Studies in 1976 which later
become the Yeager Center of Electrochemical Sciences. The Center is one of the
largest University research groups in the United States working in the field of
electrochemistry. In 1994 the Center was rededicated in his honor as the Ernest
B. Yeager Center for Electrochemical Sciences.
During
his career he served as president of the Electrochemical Society 1963-66 and
the International Society of Electrochemistry 1969-71, as well as vice
president of the Acoustical Society of America.
Among
the awards he received are the Acheson Medal and the Vittoria de Nora Medal –
both from the Electrochemical Society. He also received the Biennial Award of
the Acoustical Society of America and a Navy Certificate of Commendation, for
work as a member of the committee on undersea warfare. Prof. Yeager's research
and teaching made him internationally known. Yugoslav electrochemists, especially
those from the Belgrade electrochemistry school, considered him not only an
outstanding scientist, but also a generous person. We enjoyed travelling with
him through our country, listening to his lectures during his visits to
Belgrade, having scientific, but also general discussions with him. The members
of the Serbian Chemical Society recognized his warm feelings and were honored
to have him as a friend. Those who had the privilege to work with him, to
familiarize themselves with his huge scientific knowledge, also had the
oportunity to familiarize themselves with a man of honor, simply a great man.
We will mourn Prof. Yeager's death with the permanent feeling that a real
personality has left us.
Branislav Nikolic
|
To download this article click here 17 KB |
Errata
- In the paper entitled "The effect of reversing
current deposition on the apparent density of electrolytic copper
powder" by K.I. Popov et al. published in the Journal of the Serbian
Chemical Society, 67(1)61–67(2002) the name of one author printed as Lj.J.
Popovic should read Lj.J. Pavlovic.
- By technical mistake paginations of pages 141 and 142
appear two times. No further correction of this will be made.
Copyright & copy; SHD 2002.
Last
Updated April 9, 2002.
For
more information contact: SHD@elab.tmf.bg.ac.yu