Chiral Carbon Nanorings: Synthesis, Properties and Hierarchical Self‐assembly of Chiral Ternary Complexes Featuring a Narcissistic Chiral Self‐Recognition for Chiral Amines

Abstract

Abstract We report the synthesis and chiroptical properties of novel chiral carbon nanorings S p‐/ R p‐[12]PCPP containing a planar chiral [2.2]PCP unit, and demonstrate that S p‐/ R p‐[12]PCPP can not only host crown ether 18‐Crown‐6 to form ring‐in‐ring complexes with a binding constant 3.35×10 3 M −1 , but also accommodate the complexes of 18‐Crown‐6 and S/R ‐protonated amines to form homochiral S @ S p ‐/ R @ R p ‐ and heterochiral S @ R p ‐/ R @ S p ‐ ternary complexes, displaying significantly larger binding constants of up to 3.31×10 5 M −1 depending on the chiral guests. Importantly, homochiral S @ S p ‐/ R @ R p ‐ ternary complexes exhibit an enhanced CD signal, while the heterochiral S @ R p ‐/ R @ S p ‐ ones have a constant CD signal compared with the chiral carbon nanorings, respectively, which suggests that homochiral S @ S p ‐/ R @ R p ‐ ternary complexes display a highly narcissistic chiral self‐recognition for S / R ‐protonated chiral amines, respectively. Finally, the chiral ternary complexes can be further applied to determine the ee values of chiral guests. The findings highlight a new application of carbon nanorings in supramolecular sensors, beyond the common recognition of π‐conjugated molecules.