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

We reported the synthesis and chiroptical properties of novel chiral carbon nanorings Sp-/Rp-[12]PCPP containing a planar chiral [2.2]PCP unit, and demonstrated 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 up to 3.31×105 M-1 dependent on chiral guests. Importantly, homochiral S@Sp-/R@Rp- ternary complexes exhibit an enhanced CD signal, while heterochiral S@Rp-/R@Sp-ones remain a constant CD signal when compared with the chiral carbon nanorings, respectively, suggesting that homochiralS@Sp-/R@Rp- ternary complexes display a highly narcissistic chiral self-recognition for S/R-protonated chiral amines, respectively. Finally, 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 common recognition of π-conjugated molecules.