4th EucheMs chemistry congress

Monday, 27-Aug 2012
s781
chem. Listy 106, s587–s1425 (2012)
organic Chemistry, Polymers – ii
Physical organic methods – i
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PhotoinduCed dynAMiCS in A
terPyridine-BASed zinC(ii) CoordinAtion
PoLyMer And their MoLeCuLAr frAGeMentS
B. dietzeK 1 , A. winter 2 , u. S. SChuBert 2 ,
i. SCheBLyKin 3 , J. PoPP 4
1 IPHT, Research Group Ultrafast Spectroscopy, Jena, Germany
2 Friedrich-Schiller-University Jena, Jena Center for Soft
Matter, Jena, Germany
3 Lund University, Department of Chemical Physics, Lund,
Sweden
4 Friedrich-Schiller-University Jena, Institute of Physical
Chemistry, Jena, Germany
This contribution focuses on the photoinduced dynamics in
a ZnII-bis-terpyridine coordination polymer and its molecular
fragments – in particular the bis-terpyridine ligands bearing
conjugated chromophore units, which resemble
the structural features of poly[2-methoxy-5-(2-ethylhexyloxy)-
-1,4-phenylenevinylene] (MEH-PPV). The ZnII coordination
polymer, which forms ridgid linear macromolecular structures,
combines up to about 35 such individual MEH-PPV-like
chromophores and is investigated by single molecule fluorescence
spectroscopy. Upon incorporation of the individual chromophores
into the coordination polymer the fluorescence quantum yield of
an individual chromophore is found to be reduced. The molecular
mechanism underlying this finding is addressed by investigating
the brightness of isolated polymer molecules in various
environments. The SMS results show that the ZnII-bis-terpyridine coordination polymer with the MEH-PPV-like chromophore
structure contains a significantly larger fraction of bright
chromophores compared to MEH-PPV alone. This finding is
attributed to the particularly rigid geometry of the system at hand.
The single-molecule fluoresecence experiments will be correlated
with ultrafast time-resolved spectroscopy pointing to the
photoinduced geometrical rearrangement in the bis-terpyridine
chromophores. Finally, experiments on the ZnII coordination
polymer under different atmospheric conditions offer further
insights into the molecular mechanism and the nature of the
quenchers involved in the blinking.
Acknowledgement: Support by the Fonds der Chemischen
Industrie is acknowledged.
references:
1. R. Siebert et al. Central Eur. J. Chem. 2011, 9, 990–999.
2. R. Siebert et al. J. Phys. Chem. C 2011, 115, 12677–12688
3. R. Siebert et al. Phys. Chem. Chem. Phys 2011, 13,
1606–1617.
4. R. Siebert et al. J. Phys. Chem. C 2010, 114, 6841–6848.
5. R. Siebert et al. Macromol. Rapid Comm. 2010, 31,
883–888.
6. R. Siebert et al. Macromol. Rapid Comm. 2012, doi:
10.1002/marc.20110075
Keywords: Zn(II) coordination polymers; photophysics;
terpyridine coordination compounds; excited-state dynamics;
luminescence properties;
Physical organic methods – i
4 th EucheMs chemistry congress
o - 0 8 7
fLuoreSCenCe SPeCtrA PrediCtion of
oLiGothioPhene derivAtiveS: CoLor tuninG
By SuBStituent vAriAtion
e. horKeL 1 , B. hoLzer 1 , d. LuMPi 1 , f. PLASSer 2 ,
h. LiSChKA 2 , J. frÖhLiCh 1
1 Vienna University of Technology, Institute of Applied Synthetic
Chemistry, Vienna, Austria
2 University of Vienna, Institute for Theoretical Chemistry,
Vienna, Austria
Organic electronics [1] has gained both academic and
industrial interest during recent years. Especially organic light
emitting devices (OLEDs) have drawn much attention on them,
as they show superior properties, e.g. a higher viewing angle and
lower power consumption when compared to their inorganic
counterparts. Thus, tools assisting the efficient development of
novel materials suitable for the fabrication of OLEDs are highly
appreciated. Bis(triarylamine) substituted oligothiophenes, [2]
often described as cap-linker-cap systems, are typical
representatives for a whole class of OLED materials. Variation of
conjugation length of the oligothiophene linker as well as the
decoration of the triarylamine cap with different substituents R
enable tuning of spectral properties. Aim of this study was to
investigate the influence of the substituent R on the fluorescence
characteristics. In order to have knowledge upon this critical
property before time consuming synthesis, we evaluated the
possibility to predict fluorescence spectra by means of
computational chemistry. For this purpose time-dependent density
functional theory (TDDFT) was used, giving in the first step
information on the vertical emission, both in gas phase and in
solution. To move one step further, vibrational information was
used to get insight into the particular band shapes of the entire
spectra. Simulations based on the Wigner distribution, as
implemented in the framework of the Newton-X program
package, proved to be appropriate to perform this task. [3]
The hereby obtained spectra were compared to experimental data
to show scope and limitation of the methods under investigation.
references:
1. Organic Electronics: Materials, Manufacturing and
Applications, Hagen Klauk (editor), Wiley-VCH 2006
2. Mishra, A.; Ma, C.-Q.; Ba¨uerle, P. Chemical Reviews
2009, 109, 1141.
3. http://www.univie.ac.at/newtonx/
Keywords: Density functional calculations; Fluorescence;
Sulfur heterocycles; Semiconductors;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc