[Todos] Seminarios DQIAQF - INQUIMAE, lunes 30 de Mayo - 13 hs.

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Seminarios DQIAQF - INQUIMAE,  lunes 30 de Mayo - 13 hs.

Aula de Seminarios INQUIMAE - DQIAQF
Facultad de Ciencias Exactas y Naturales
Ciudad Universitaria - Pab. 2  -  Piso 3

Cristian A. Strassert
Physikalisches Institut and Center for Nanotechnology (CeNTech)
Westfaelische Wilhelms-Universitaet Muenster
Heisenbergstrasse 11, D-48149 Muenster (Germany)
E-mail: ca.s en uni-muenster.de


“To aggregate or not to aggregate: that is the question”

Aggregation of planar chromophores greatly affects their photophysical
performance. Phthalocyanine derivatives tend to form inactive dimers or
oligomers, while Pt(II) complexes can show efficient emission from the
MMLCT triplet state. It is possible to avoid the aggregation of
phthalocyaninates by axially binding them to the surface of
aluminosilicates. We have recently designed a multifunctional zeolite
L-based hybrid material able to target, label and photoinactivate
pathogenic and antibiotic resistant bacteria. A highly green luminescent
dye was inserted into the channels of zeolite L nanocrystals for imaging
and labeling the cells. The outer surface was functionalized with a Si(IV)
phthalocyanine derivative that forms toxic singlet oxygen upon red light
irradiation, and with amino groups for targeting the living microorganisms
[1].
On the other hand, we recently developed a straightforward one-pot
synthesis of neutral, soluble Pt(II) coordination compounds bearing a
dianionic tridentate, terpyridine-like ligand. The emission intensity of
the complex reached up to 87% PLQY in thin films, with concentration
independent colour and efficiency. Consequently, we demonstrated its
suitability as a dopant in solution processed OLEDs. Furthermore, we
discovered that this complex is also able to self-assemble to bright
nanofibers, which can interlock to yield highly emissive gels (90% PLQY),
thus constituting a versatile building block for luminescent
architectures. Therefore, it is possible to obtain two different materials
starting from one single molecular entity, and monitor the self-assembly
process with high sensitivity by the turn-on of the emission upon
aggregation. The unique photophysical properties of the bright emitter
arise from aggregation, as evidenced by the excitation and emission
spectra, as well as excited state lifetimes [2].

[1] Strassert, C. A.; Otter, M.; Albuquerque, R. Q.; Höne, A.; Vida, Y.;
Maier, B.; De Cola, L. Angew. Chem. Int. Ed. 2009, 48, 7928-7931.

[2] Strassert, C. A.; Chien, C.-H.; Galvez-Lopez, M. D.; Kourkoulos, D.;
Hertel, D.; Meerholz, K.; De Cola, L. Angew. Chem. Int. Ed. 2011, 50,
946-950.