Effect of π‐Electron Conjugation on the Chiroptical Properties of Helicene Carbon Nanohoops

Abstract We designed, synthesized, and investigated a new chiral carbon nanohoop that formally incorporates a benzothiadiazole and [5]helicene units into the structure of [6]cycloparaphenylene. The connection of these units in the chiral nanohoop is designed to allow for π‐electron conjugation between the benzothiadiazole chromophore and the chirality‐inducing [5]helicene. We resolved the enantiomers of the highly fluorescent, near‐IR light emitting benzothiadiazole helicene nanohoop. Electronic circular dichroism spectroscopy then allowed us to investigate whether the selected molecular design leads to an increase in the lowest singlet excited state delocalization to improve the compound's electronic dissymmetry factor in comparison to the previously studied benzothiadiazole carbon nanohoop with planar chiral [2.2]paracyclophane unit with pseudo‐meta connection.