4th EucheMs chemistry congress

Poster Session 2
s1360
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - organic chemistry
P - 0 9 9 6
SyntheSiS And ProPertieS of noveL
SeMiConduCtinG donor-ACCePtor MAteriALS
C. teuSCh1 , M. ALt2 , n. MeChAu2 , u. Bunz1 ,
K. MüLLen1 , M. hAMBurGer1 1 University of Heidelberg, Organisch-Chemisches Institut,
Heidelberg, Germany
2 Karlsruher Institut für Technologie, Lichttechnisches Institut,
Karlsruhe, Germany
In Organic Electronics there is a permanent need for new
electron-conducting materials. To that end, an entire series of
different acceptors such as fullerenes, phthalocyanines and
rylene-type dyes has already been successfully examined. [1]
Nitrogen-containing acenes are a class of semiconducting
materials which are highly interesting for their application in
organic electronics. [2] An exciting extension of this topic is the
connection of these acceptors to donor molecules to form
π-conjugated oligomeric and polymeric compounds in order to
adjust electronic properties and to induce intramolecular and
intermolecular interaction, which enhances charge carrier
transport. [3]
Herein, we will report on the synthesis of symmetric
donor-acceptor-donor systems which can be easily synthesized by
Pd-catalyzed cross-coupling. According to DFT-calculations,
these materials show a HOMO-LUMO gap that would make them
candidates as absorber materials for organic solar cells.
Furthermore, the energies of the frontier molecular orbitals seem
to make the synthesized compounds capable of serving as
semiconductors in OTFTs (organic thin film transistors).
The opto-electronic properties of the oligomers will be
examined both in solution and in thin films; their semiconducting
properties will be studied in field-effect transistors.
As one aspect of future studies will be printing of these
materials, special focus will be on their solubility in nonchlorinated
solvents.
references:
1. H. Hoppe, N. S. Sariciftci, J. Mater. Res. 2004, 19,
1924–1945.
2. U. H. F. Bunz, Pure Appl. Chem. 2010, 82, 953–968.
3. Z.-G. Zhang, J. Wang, J. Mater. Chem. 2012, 22,
4178–4187.
Keywords: Organic Electronics; Donor-acceptor systems;
Electron transport;
4 th EucheMs chemistry congress
P - 0 9 9 7
MoLeCuLAr dyAdS with StronG PuSh-PuLL
ChroMoPhoreS AS eLeCtron ACCePtorS:
SyntheSiS And PhotoPhySiCAL ProPertieS
L. urner 1 , K. howeS 1 , h. BeLBAKrA 2 ,
P. reutenAuer 1 , A. LiStorti 2 , n. ArMAroLi 2 ,
f. diederiCh 1
1 ETH Zurich, Laboratory of Organic Chemistry, Zürich,
Switzerland
2 Instituto Per La Sintesi Organica E La Fotoreattivita,
Consiglio Nazionale delle Ricerche, Bologna, Italy
One of the approaches in the development of organic solar
cells (OSCs) is the molecular one, wherein a donor (D) and an
acceptor (A) are covalently attached to a bridging unit (B) in a
molecular dyad. While impressive progress has been made in
OSC development, one of the limiting factors, in particular of
covalent D–B–A dyads, has been the restricted set of acceptors
used so far, mainly comprising derivatives of fullerenes, perylene
diimides, and quinones.
As an alternative to the often used fullerenes, a new class of
strong organic electron acceptors (push-pull chromophores) has
been introduced by the Diederich group into covalently linked
donor-acceptor systems for photoinduced electron transfer (PET).
These “superacceptors” are accessible by a versatile [2+2]
cycloaddition (CA), between electron-rich alkynes and
electron-poor alkenes, e.g. tetracyanoethylene (TCNE), followed
by a retro-electrocylization (RE). [1, 2] The superacceptors have
been incorporated into covalently linked molecular dyads with a
meso-trans-bis(3,5-di-tert-butylphenyl)-zinc-porphyrin as electron
donor. The photophysical properties of these molecular dyads and,
of according reference compounds have been studied using steady
state and time-resolved absorption and luminescence
spectroscopies, both as solutions in aerated and deaerated toluene
and benzonitrile.
As evidenced by nanosecond transient absorption
spectroscopy, the main deactivation pathway for dyad 1 is energy
transfer, and electron transfer in the case of dyads 2 and 3. In
benzonitrile, dyad 2 exhibits a long-lived charge-separated state
of 2.3 µs. Further studies with this new promising class of
acceptors are under way to examine their potential for PET in rigid
molecular dyads, and as novel materials for OSCs.
references:
1. T. Michinobu, C. Boudon, J.-P. Gisselbrecht, P. Seiler,
B. Frank, N. N. P. Moonen, M. Gross, F. Diederich, Chem.
Eur. J. 2006, 12, 1889.
2. P. Reutenauer, M. Kivala, P. D. Jarowski, C. Boudon,
J.-P. Gisselbrecht, M. Gross, F. Diederich, Chem.
Commun. 2007, 46, 4898.
Keywords: Molecular electronics; Electron transfer; Energy
transfer; Supramolecular chemistry; Porphyrinoids;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc