Molecular Approach to Conjugated Materials

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Understanding the interaction of light or electrons with matter continues to be an aim in science. Fundamental understanding of these interactions would enable efficient, flexible solar cells or lighting applications through organic light emitting diodes. Using synthetic chemistry we strive to explore the synthesis, optical and electrochemical properties of organic molecules. In practice, we design organic molecules that interact with light and electrons. Most of the proposed research program is devoted to organic synthesis by bringing new molecular scaffolds, which is critical to success of any disruptive technology and each of our aims is tied to applications that will benefit Canadians, such as food supply, efficient solar cells and lighting, tools for bioimaging to map disease states, or new drug delivery methods. Our first aim explores organic molecules as room temperature phosphorescence, once believed to be impractical due to oxygen quenching. Organic compounds that glow after they have been `charged' via photoexcitation - think star stickers on a child's ceiling - are rare and molecular design rules are absent; we propose filling that knowledge void. Fundamentally, understanding and tuning the excited-state materials has significant implications in the operation of organic LEDs and solar cells. Our second aim proposes to make significant progress on two applications - anion sensors and bioimaging. We propose anion sensors that change colour when interacting with specific anions by targeting phosphates, sulfates and nitrates for our sensor design. These anions play critical roles in food supply and precision fertilization strategies are seen as a method to enhance production and limit eutrophication. Cyanine dyes have been used extensively as bioimaging tags to discover the action of biological processes. As more complex bioprocesseses are being revealed there is demand for mutil-coloured emission tags and our proposal re-imagines the syntheses of this dye class, adding considerable structural and colour diversity. Finally, we propose a series of molecules that have bent shapes to achieve two application goals - drug delivery and phase separation. Water and oil phase-separate when mixed because of hydrophobic effects and we suggest phase separation between shape mismatched molecules can achieve the same outcome. Phase segregation at the nanoscale has been an idealized target in the organic materials community and this approach could be an orthogonal tool to achieve this goal. Our bent-shape molecules also undergo planarization when excited by light. When two bent-shape molecules are linked into a large cycle, such that the cavity holds a drug, and upon light excitation a change in molecular shape expels the drug. This is an untested drug delivery mechanism that offers much fundamental dynamics investigation.