The synthesis, characterization and application of the binol-cages of R-/S-enantiomers

In the past few years, significant efforts have been made to create and self-assemble covalent organic cages with increased complexity and functionality. However, although supramolecule cages have been widely recognized as probes to identify metal ions, the detection of mercury ions has not been fully developed. Here, we have designed and synthesized a pair of chiral cages with custom cavities based on the unique rigid structure of 1, 10-binaphthol (binol). Meanwhile, the supramolecular cage has excellent performance in high sensitivity and selectivity for detecting mercury ions. The UV titration results indicate that the binding ratio of the host to guest is 1:5. The titration curve conforms to the nonlinear fitting of the Hill function, which can obtain the binding constant K = 2.57 × 105 M-1 . Furthermore, the detection limit of 1.9 × 10-7 M can be obtained because the absorbance of cages exhibits a strong linear relationship with Hg2+ concentrations. This work provides a new method for selective recognition of ions by supramolecular cages.