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

Abstract

AbstractWe report the synthesis and chiroptical properties of novel chiral carbon nanorings Sp‐/Rp‐[12]PCPP containing a planar chiral [2.2]PCP unit, and demonstrate that Sp‐/Rp‐[12]PCPP can not only host crown ether 18‐Crown‐6 to form ring‐in‐ring complexes with a binding constant 3.35×103 M−1, but also accommodate the complexes of 18‐Crown‐6 and S/R‐protonated amines to form homochiral S@Sp‐/R@Rp‐ and heterochiral S@Rp‐/R@Sp‐ ternary complexes, displaying significantly larger binding constants of up to 3.31×105 M−1 depending on the chiral guests. Importantly, homochiral S@Sp‐/R@Rp‐ ternary complexes exhibit an enhanced CD signal, while the heterochiral S@Rp‐/R@Sp‐ ones have a constant CD signal compared with the chiral carbon nanorings, respectively, which suggests that homochiral S@Sp‐/R@Rp‐ 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.