C O MMU N I C A T I O N S
Figure 1. Solution fluorescence of the 96 polymers measured at 530 nm
excitation 460 nm).
(
Figure 2. Solid-state fluorescence of the 96 film spots library measured at
425 nm (excitation 360 nm).
that the fluorescence of polymers was really the consequence of
the carbon-carbon coupling of two monomers. To ascertain
whether this HTE approach based on small volumes (200 to 400
µL) was accurate, the fast-detected polymers were prepared in large
scale (5- to 10-mL solutions). The emission spectra of the new
polymers C10, G8, and H8 clearly indicated that results obtained
from the HTE approach reflected the real fluorescence properties
of polymers.10 Moreover, this was confirmed with polymers already
described G6 and G5 as the information obtained from the
corresponding solutions in the 96-well plate are in good concordance
with the results in the literature.10 However, for aplication as OLED
devices new solid-state fluorescent polymers are required. Due to
the presence of aggregates, excimers, or both11 the emission color
of conjugated polymers in solid state could be different than the
color obtained from a solution. As this effect is unpredictable, 96
film spots were prepared by the slow evaporation of 20 µL of each
polymer solution. Again, a simple irradiation of this plate with a
hand-held UV lamp (365 nm) led to the visualization of the color
emitted by the fluorescent polymers. With a 96-well plate reader
spectrofluorimeter, a large library of 3D graphs was obtained for
several different excitation/emission wavelengths combinations. In
this way, polymers showing a blue fluorescence in solid-sate B4,
B5, B10, H10, and the recently reported polymer D1012 were
detected (Figure 2). These results were in accordance with the color
seen for the different film spots after irradiation of the plate with
the hand held fluorescence lamp. In addition to their unexpected
necessitate significant amounts of all starting monomers. With this
fast prescreening test reported here, only compounds showing the
targeted solid-sate fluorescence have to be prepared in large scale
and carefully investigated for OLED properties. This could be done
by the classical one-by-one evaluation because the number of
potential candidate is strongly reduced or again by the HTE
14
approach. The evaluation for OLED properties of new polymers
and the studies of others libraries by this approach are in progress.
Acknowledgment. We are grateful to the CNRS, to the
MENRT, to the R e´ gion Bretagne, and to the company TotalFinaElf
for their support for the Project Organometallic Combinatorial
Chemistry.
Supporting Information Available: Experimental protocol for the
synthesis and fluorescence screening of the library and for the synthesis
of selected polymers and monomers (PDF). This material is available
free of charge via the Internet at http://pubs.acs.org.
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4
(
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