C1 (Czekelius)

Abstract:

Flavins play an important dual role in biological systems. As redox mediators (i.e. as FAD/FADH2) they serve as a pivotal cofactor in many central biochemical transformations. In addition, flavins are employed by nature for both bioluminescent systems and blue light-absorbing photoreceptors. This has sparked the scientific interest in their luminescent behavior and it was found that they in fact exhibit very rich photophysics. A modification in the substitution pattern of the flavin core, subtle changes in the surrounding´s polarity or conformational restrictions often have a tremendous impact on absorption/fluorescence energies, absorption coefficients as well as quantum yields. Fluorine is a very potent substituent with respect to tailoring photophysical and biological properties. Because of its small size, introducing it into a molecule causes little steric changes. Therefore, fluorinated flavins should fit into the pocket of most flavin-binding proteins. The large electronegativity of fluorine stabilizes molecules with respect to (photo)-oxidation and promises large effects on excitation energies. In this project, flavin analogs with specific fluorine substitution on A-, B- or C-ring will be synthesized. For this, novel synthetic methodology for late-stage fluorination will be developed involving transition metal catalysis as well as photocatalysis and electrosynthesis.