4th EucheMs chemistry congress

Poster Session 2
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chem. Listy 106, s257–s1425 (2012)
Poster session 2 - Nanochemistry, Nanotechnology
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hoSt-GueSt CoMPLexeS: how SMALL
StruCturAL ChAnGeS And MuLtivALent
effeCtS CAn hAve A LArGe iMPACt on BindinG
ProPertieS
L. KAufMAnn 1 , n. L. LÖw 1 , h. SChrÖder 1 ,
n. f. KÖniG 1 , J. huuSKonen 2 , K. riSSAnen 2 ,
C. A. SChALLey 1
1 Freie Universität Berlin, Chemistry and Biochemistry, Berlin,
Germany
2 University of Jyväskylä, Chemistry, Jyväskylä, Finland
The binding behavior of differently substituted diamide axle
molecules to Hunter/Vögtle tetralactam macrocycles was studied
with a combination of NMR titration, ITC experiments, crystal
structures, and density functional calculations. Therefore, it could
be shown that substituents have a decisive effect on the binding
situation: guests with alkyl or alkenyl chains attached to the
diamide carbonyl groups have a significantly higher binding
affinity to the macrocycle than guests with benzoyl amides and
their substituted analoga. In these cases, the electronic effects of
para-substituents at the benzoyl moieties determine the binding
affinities. Electron donating substituents increase, while electronwithdrawing
substituents decrease the binding energies until
nearly no binding could be observed anymore.
These results not only have an impact on the design of
template effects for rotaxane synthesis, but all the more they are
the basis for our synthesis of multivalent host-guest complexes
based on pseudorotaxane structure, which are formed through an
interplay of self-organization, self-sorting, template effects and
multivalent interaction.
The synthetic accessibility of these components allows the
design of analogous series of pseudorotaxanes with different
number of binding sites and thus a systematic evaluation of
multivalent binding situations can be realized.
Keywords: Pseudorotaxanes; Host-guest complexes;
Multivalency; NMR titration;
4 th EucheMs chemistry congress
P - 0 7 4 4
SyntheSiS And SuBSequent uSe of iron oxide
nAnoPArtiCLeS And SiLver nAnoPArtiCLeS
M. KiLiAnovA 1 , r. PruCeK 1 , J. tuCeK 1 ,
A. PAnACeK 1 , L. KviteK 1 , M. KoLAr 2
1 Palacky University in Olomouc, Regional Centre of Advanced
Technologies and Materials and Department of Physical
Chemistry, Olomouc, Czech Republic
2 Palacky University in Olomouc, Department of Microbiology,
Olomouc, Czech Republic
Nanoparticles of magnetic iron oxides, magnetite and
maghemite, present materials, which are due to their specific
properties used as biological sensors, catalysts, adsorbents,
carriers of drugs, contrast agents in magnetic resonance and in
many other applications. Nanoparticles of silver are regarded to
be another interesting nanomaterial, they are commercially used
because of their high antibacterial activity. By combining these
nanoparticles, we gain nanocomposites of iron oxide nanoparticles
and silver nanoparticles - Ag@Fe O and γ-Fe O @Ag. Magnetic
3 4 2 3
nanocomposites present one of the remarkable developed
materials of nanotechnology research. Thanks to their magnetic
properties, they can be efficiently transported to the required place
of the human body by external magnetic field.
We prepared these nanocomposites by the chemical
reduction of silver ions in the presence of magnetic iron oxides,
polyacrylic acid sodium salt and D-maltose. The prepared
nanocomposites were characterized by transmission electron
microscopy, SQUID magnetometry, X-ray powder diffraction,
atomic absorption spectroscopy and Mössbauer spectroscopy.
Both nanocomposites were tested for their antibacterial activity
and cytotoxicity. For tested bacteria species there was obtained
minimal inhibition concentration (MIC) ranges from 15.6 mg/L
to 125 mg/L and for tested candida species the MIC levels range
from 1.9 mg/L to 31.3 mg/L. To the contrary, acute cytotoxicity
against mice embryonal fibroblasts was observed at
concentrations of higher than 292 mg/L for γ-Fe O @Ag
2 3
nanocomposite and 430 mg/L for nanocomposite Ag@Fe O . 3 4
Keywords: nanoparticles; iron; silver; magnetic properties;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc