4th EucheMs chemistry congress

Poster Session 1
s935
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - inorganic Chemistry
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whAt iS the StruCturAL ArrAnGeMent to
AChieve hiGh in vitro AntirAdiCAL ACtivity
of Cu(ii) CoMPLexeS invoLvinG AntioxidAnt
Kinetin And itS derivAtiveS?
r. novotná 1 , r. herCheL 1 , z. trávníCeK 1
1 Regional Centre of Advanced Technologies and Materials
Palacky University in Olomouc, Department of Inorganic
Chemistry, Olomouc, Czech Republic
The metalloenzyme Cu, Zn-superoxide dismutase (Cu,
Zn-SOD) plays a key role in the cell protection against reactive
oxygen species because it catalyses the disproportionation of the
superoxide radical to oxygen and hydrogen peroxide [1] . Cu,
Zn-SOD whose active site contains the imidazole-bridged copper
and zinc atoms [2] has become a model compound for the synthesis
of low-molecular antioxidants based on Cu(II) complexes [3] .
Kinetin (N6-furfuryladenine) belongs among plant growth
hormones cytokinins [4] . At present, due to its significant
anti-ageing effect, it has been used in medicinal cosmetics.
Kinetin itself exhibits intrinsic antioxidative properties [4] , thus
coordinating kinetin to copper (possible synergic effect) might
lead to compounds with auspicious SOD-mimic activity.
Depending on the substitution on the kinetin molecule and
on the reaction conditions, nine structurally varied complexes
were prepared. The polymeric [Cu (μ -L 2 3 n ) (μ -Ac) ] (1–3),
2 2 2 n
dimeric [Cu (μ -Ac) (HL 2 2 4 n ) ] (4, 5) [5], [Cu (μ-HL 2 2 n ) Cl ]Cl (6),
4 2 2
[Cu (μ-HL 2 n ) (μ-Cl) (HL 2 2 n ) Cl ] (7) and mononuclear
2 2
[Cu(H O) (L 2 2 n ) (phen)] (8, 9) complexes (HL 2 n = kinetin and its
derivatives; phen = 1,10-phenanthroline) were characterized by
elemental, thermal analyses, spectroscopic methods (IR, UV-Vis),
conductivity, magnetochemical measurements and single crystal
X-ray analysis. In vitro SOD-mimic activity was tested for all the
compounds, while the best result was observed for complex 7 with
IC = 0.71 μM (70% activity of native Cu, Zn-SOD). The
50
influence of the various structural types of the complexes on
SOD-mimic activity will be discussed.
Acknowledgement: The financial support is gratefully
acknowledged: CZ.1.05/2.1.00/03.0058,
CZ.1.07/2.3.00/20.0017, PrF_2012_009.
references:
1. Xu K.Y., Kuppusamy P.: Biochem. Biophys. Res.
Commun. 336 (2005) 1190.
2. Strothkamp K.G., Lippard S.J.: J. Acc. Chem. Res. 15
(1982) 318.
3. Starha P., Trávnícek Z., Herchel R., Popa I., Suchý P.,
Vanco J.: J. Inorg. Biochem. 103 (2009) 432.
4. Barciszewski J., Rattan S.I.S., Siboska G., Clark B.F.C.:
Plant Sci. 148 (1999) 37.
5. Novotná R., Herchel R., Trávnícek Z.: Polyhedron 34
(2012) 56.
Keywords: Cu(II) complexes; kinetin; in vitro antiradical
activity;
4 th EucheMs chemistry congress
P - 0 1 4 9
the KinetiCS of SiLiCon tetrAChLoride
CAtALitiC reduCtion By hydroGen on niCKeL
ChLoride
A. vorotyntSev 1
1 Nizhny Novgorod State Technical University n.a. R.Y. Alekseev,
FTMCET department, Nizhny Novgorod, Russia
Nowadays it pays special attention to the reaction of silicon
tetrachloride reduction due to its great importance in the
technological cycle of production of polycrystalline silicon,which
is used,for the microelectronics industry.Modern technology for
getting silicon is based on the hydrochlorination of silicon to
trichlorosilane with its following separation from the gas-vapor
mixture and purification from impurities and hydrogen reduction.
Besides, the method of thermal decomposition of silane is
used for silicon production, which is produced by trichlorosilane
disproportionation.In this way it forms from 14 to 16kg of silicon
tetrachloride as a byproduct per 1kg of the receivable silicon.
Thus from the economic and environmental points of view
the whole amount of processing silicon tetrachloride have to be
convert into less energy-intensive raw materials,which can be
used in semiconductor silicon production.The purpose of realizing
such scheme is the design of closed cycle of silicon production.
In this work we studied the reduction reaction of silicon
tetrachloride in the presence of a catalyst based on nickel chloride,
investigated the kinetics of the process, as well as identify the
order and activation energy of the reaction studied. It’s found that
chlorine transfer from molecule of chlorosilanes to molecule of
hydrogen and hydrogen chloride formation is one of the main
reactions occurring on the catalyst surface.The mechanism of the
reaction is confirmed by X-ray phase and chemical analysis. A
quantum-chemical modeling of the studied reactions is in a good
agreement with experimental data.
The conversion of silicon tetrachloride at 250°C was
obtained up to 85%.It was proved by gas chromatographic
analysis of vapor-gas mixture, which is leaving the reactor with
catalyst.The catalyst porosity was 60%.Thus the conversion ratio
was increased from 30% to 85% with the process temperature
decreeing in 4 times.These outstanding results can provide the
opportunity to creati of green technology of silicon production.
Keywords: silicon tetrachloride; catalytic reduction; nickel
chloride;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc