Grants and Contracts Details
Description
Herein we propose to investigate the scope of novel carbon-carbon bond forming reaction which
is particularly well-suited to the preparation of organic conjugated polymers. The coupling
reaction occurs between silyl-functionalized monomers, in which the silicon group is attached to
sp and Sp2 carbons, and highly fluorinated arenes. With each new bond-formation, the reagent
which induces the reaction (fluoride ion) is regenerated. The reaction therefore proceeds to high
yields producing high-molecular weight polymers, requiring only a minute (catalytic) amount of
fluoride additive. Chemically pure polymers are produced with well-defined end-groups. High
purity is also possible because the fluoride ion source and the sole side product (a gas) are very
easily removed. The reaction is a highly attractive alternative to transition-metal catalyzed
reactions which currently dominate the field.
The viability of the method to prepare a number of classes of technologically relevant conjugated
polymers will be investigated. These include alternating copolymers of thiophene derivatives,
poly(arylene ethynylene)s, and poly(arylene vinylene)s. Practical syntheses of all requisite
silane-functionalized monomers are outlined. To facilitate the delineation of the reactivity of
each new monomer, model studies will be conducted to prepare small molecules which may
more easily be characterized by standard techniques, thus gaining more reliable proof of the
efficacy of the reaction. Since nearly all of the materials proposed herein are without precedent,
structure-property studies will also be conducted to evaluate the effect of a perfectly-alternating
structure on thermal, optical, and self-assembly properties. Methods to be used in these
structure-property studies are wide-angle x-ray diffraction, thermal polarized optical microscopy,
differential scanning calorimetry, thermo gravimetric analysis, and standard spectroscopic
techniques including absorption and emission spectroscopy. In an iterative approach, new
polymers will be designed with differing side-chains in order to engineer these properties.
The materials chosen for this study all have promise as low-cost active components in consumer
electronics. The presence of perfluoroarene groups has already been demonstrated to positively
affect the properties of small molecule semiconductors. However, prior attempts at polymers
similar to those proposed here failed to show any great benefit. In some cases, very poor
solubility precluded evaluation, while others used synthetic methods leading to ill-defined
structures. The cleanliness of the method proposed herein, together with a systematic plan to
vary substituents until soluble polymers are obtained, guarantees that the study will provide
materials leading to an understanding of the effect of fluorination on the properties of conjugated
polymers.
Given the broad interest in functionalized, highly fluorinated aromatics in such diverse fields as
ligands for transition-metal catalysts and pharmaceuticals, the proposed research is expected to
stimulate interdisciplinary progress.
Status | Finished |
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Effective start/end date | 11/1/05 → 10/31/06 |
Funding
- KY Science and Technology Co Inc: $50,000.00
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