Design and Synthesis of Helically Chiral BODIPY Dyes through Point-to-Helical Chirality Transfer

Abstract

The boron dipyrromethenes (BODIPYs) are a class of fluorescent organic dyes that have found use in numerous applications, due to their excellent photophysical properties including high fluorescence quantum yields. Chiral BODIPYs are of interest as they have the potential to emit circularly polarized light upon irradiation, however the synthesis of such systems is challenging. In this thesis, we have examined several new methodologies to access chiral BODIPYs. In particular, we have focused on the development of a point-to-helical chirality transfer strategy in which an enantiopure amino alcohol substituent can be used as a chiral auxiliary to control the formation of helical chirality in the target BODIPY. We have applied this point-to-helical chirality approach to the synthesis of a wide range of novel helical chiral BODIPY architectures, including monomeric helically chiral N,N,O,C-BODIPYs containing a 7-membered ring, monomeric helically chiral N,N,O,C-BODIPYs containing a 6-membered ring, as well extending this approach to dimeric and trimeric helically chiral N,N,O,C-BODIPY systems (Scheme 1). (Diagram unable to view in abstract) Scheme 1: The synthesis of helically chiral BODIPYs via point-to-helical chirality transfer (Ar = p-(MeCO2)-C6H4-). Overall, we have shown that our newly developed point-to-helical chirality transfer approach can be applied broadly in the design and synthesis of a wide range of helical chiral BODIPYs, which have potential for further development towards chiroptical materials in the future.