A modular family of chiral cavitand receptors: tuning the chiroptical response of achiral fullerene guests

Abstract

A new family of chiral self-folding cavitand receptors based on calix[5]arene has been developed. The cavitand synthesis is modular and highly convergent, relying on a late-stage amide formation step that allows facile diversification with different chiral amines and straightforward access to either enantiomer of the host. This strategy provides access to a set of structurally diverse and conformationally flexible cavitands that efficiently bind fullerene derivatives. The resulting host-guest complexes exhibit induced electronic circular dichroism response in the spectral window of the achiral fullerene chromophore. The modular nature of the cavitand scaffold allows tuning of the chiroptical response of a given fullerene across the visible spectrum.