4th EucheMs chemistry congress

tuesday, 28-Aug 2012
s817
chem. Listy 106, s587–s1425 (2012)
Physical, theoretical and Computational Chemistry
theoretical Chemisry – iii
o - 2 4 0
oPtiCAL ProPertieS And uLtrAfASt dynAMiCS
of PorPhyrin ArrAyS
M. roehr 1 , J. PeterSen 1 , v. BonACiC-KouteCKy 2 ,
r. MitriC 1
1 Freie Universität Berlin, Fachbereich Physik, Berlin, Germany
2 Humboldt Universität zu Berlin, Fachbereich Chemie, Berlin,
Germany
Multiporphyrin arrays represent ideal building blocks for
optoelectronic and light-harvesting materials since they can be
produced in different shapes including oligomers and
two-dimensional polymers. Great variability of possible
multiporphyrin arrays allows to tailor their optical properties. We
present here the theoretical study of the optical properties and
ultrafast dynamics of different classes of porphyrin oligomers.
We assign the optical spectra of these systems by using
semi-empirical multi-reference and configuration interaction
(MR-CI) method. Furthermore, we investigate the influence of
specifically designed charged ligands on the optical absorption
and the optical band gap of porphyrin oligomers. Since the
functionality of optoelectronic and light-harvesting materials is
determined by the interplay between the radiative and
nonradiative relaxation processes, we perform surface hopping
simulations of the ultrafast dynamics in order to determine the
mechanism of the excited state relaxation in porphyrin oligomers.
Keywords: Molecular dynamics; Porphyrinoids;
theoretical Chemisry – iii
4 th EucheMs chemistry congress
o - 2 4 1
StoChAStiC KinetiC ModeLinG of the SoAi
reACtion
L. GABor 1 , d. evA 1
1 University of Debrecen, Institute of Chemistry Department of
Inorganic and Analytical Chemistry, Debrecen, Hungary
The Soai reaction, which involves carbon-carbon bond
formation using an organozinc reagent, is the best known example
of absolute asymmetric synthesis [1] . In this presentation, it will be
demonstrated how the experimentally observed distribution of
enantiomers in the Soai reaction can be interpreted based on a
chemical mechanism using a newly developed stochastic kinetic
method, accelerated Monte Carlo simulation combined with
deterministic continuation and symmetrization. The method is in
principle suitable for handling large mechanisms with realistic
particle numbers and could be useful for any case where the
kinetics of a process shows inherent random fluctuations. The
mechanism shows how a slow initial reaction combined with
efficient and highly enantioselective autocatalysis can give rise to
chiral symmetry breaking under completely nonchiral external
conditions [2] .
Acknowledgement: This work was supported by the TÁMOP
4.2.1/B-09/1/KONV-2010-0007 project, which is co-financed by
the European Union and the European Social Fund.
references:
1. Soai, K.; Sato, I.; Shibata, T.; Komiya, S.; Hayashi, M.;
Matsueda, Y.; Imamura, H.; Hayase, T.; Morioka, H.;
Tabira, H.; Yamamoto, J.; Kowata, Y. Tetrahedron:
Asymm. 2003, 14, 185–188.
2. Dóka, É.; Lente, G. J. Am. Chem. Soc. 2011, 133,
17878–17881.
Keywords: Kinetics; Asymmetric amplification; Autocatalysis;
Enantioselectivity; Chirality;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc