Enantiomerically Resolvable Inherent Chirality Induced by Strong Para -Steric Hindrance in Cycloparaphenylene-Based Carbon Nanohoops.

The chemical modification of the achiral carbon nanohoops to break the symmetry will result in inherently chiral structures with interesting optical properties. Herein, we report two novel π-extended chiral macrocycles, cyclo[10]paraphenylene-pyrene ( [10]CPP-2Pyrene ) and cyclo[10]paraphenylene-hexa-peri-hexabenzocoronene ( [10]CPP-2HBC ). The large substituents on the nanohoop peripheries effectively prevented free rotation and the racemization process. The conformation of each enantiomer is stable enough to be resolved by recycling HPLC.