Chiral macrocycles forming high-affinity host-guest homoternary complexes for chiral discrimination and amplified circularly polarized luminescence
Rong Fu, Fangyuan Chen, Le Dai, Dai‐Yuan Li, Qingyu Zhao, Si‐Dan Guo, Zihang Song, Li‐Bo Jing, Heng Wang, Xiaopeng Li, Dong‐Sheng Guo, Kang Cai
Abstract
The development of macrocyclic hosts with high-affinity 1:2 recognition capabilities is crucial for advancing supramolecular chemistry and its applications. While cucurbit[8]uril (CB[8]) has long been recognized for its unparallel 1:2 binding affinity, its limitations—including poor solubility, difficulty to modify and lack of optical activity—have hindered broader utilization. Here, we introduce a class of enantiopure chiral macrocycles, RRRR- or SSSS-corral[4]BINOL (C[4]Bs), which exhibit remarkable 1:2 recognition properties in water that are comparable or even surpass CB[8]. Using UV-Vis, fluorometric, and isothermal titration calorimetry (ITC), we demonstrate that C[4]Bs form stable homoternary complexes with 11 singly positively charged planar aromatic guests, with binding affinities up to 1017 M−2. These ultrahigh affinities make C[4]Bs versatile alternatives to CB[8], offering advantages such as superior water-solubility, ease of structural modification, and strong fluorescence. Furthermore, the unique chiral nature of C[4]Bs enables efficient fluorescent discrimination of chiral substrates and chirality transfer to non-chiral dyes, resulting in strong circularly polarized luminescence (CPL) with |glum | values up to 1.1 ×10−2. This study establishes C[4]Bs not only as powerful hosts for aqueous-phase supramolecular complexation but also as a promising platform for developing chiral functional materials. The development of macrocyclic hosts with high-affinity 1:2 recognition capabilities is crucial for its applications. Here, the authors introduce enantiopure chiral macrocycles with remarkable 1:2 recognition properties in water comparable to those of cucurbit[8]uril.