Chiral π-Conjugated Systems for Next-Gen Photonics & Electronics? CPL and Charge Transport in Helical Aromatics

Inherently chiral helicenes[1] represent a fascinating class of non-planar π-conjugated molecules, where structural chirality and extended conjugation gives rise to unique electronic and optical properties. Their rigid, helical architectures allow for precise control over molecular handedness, enabling diverse applications in enantioselective catalysis, chiral recognition, supramolecular self-assembly, and surface chemistry. In this talk, I will briefly introduce the versatile synthetic strategy towards helicenes via intramolecular [2+2+2] cycloisomerisation of aromatic triynes, followed by a focused discussion on their circularly polarised luminescence (CPL) behaviour and charge transport properties. The latter are probed at the single-molecule level using the scanning tunneling microscope break-junction (STM-BJ) technique.[2] Special emphasis will be placed on helicene-based hybrids that exhibit significantly enhanced chiroptical responses, achieving some of the highest glum dissymmetry factors and BCPL brightness values reported for small molecules.[3] These results highlight the potential of helicenes as multifunctional building blocks in the development of advanced organic photonic and electronic materials. 1 Stará, I. G.; Starý, I. Acc. Chem. Res. 2020, 53, 144. 2 Nejedlý, J.; Starý, I.; Stará, I. G. et al. J. Org. Chem. 2020, 85, 248. 3 Submitted.