Self-Assembly of a Tetraphenylethylene-Based Capsule Showing Both Aggregation- and Encapsulation-Induced Emission Properties

Functional molecular capsules have attracted a lot of attention in recent years because of their potential applications as chemosensors, catalysis, drug carriers, and so on. We report here the coordination-directed self-assembly of a fluorescent-lantern-type molecular capsule from four tetraphenylethylene-based ditopic ligands and two square-planar palladium­(II) ions. The capsule has been thoroughly characterized by UV–vis, 1D/2D NMR, electrospray ionization time-of-flight mass spectrometry, and single-crystal X-ray diffraction studies. The aggregation-induced emission performance of the capsule has been studied by tuning the ratio of mixed solvents. Moreover, with an open cavity, the fluorescence of the capsule also displays anion sensitivity, with the best turn-on responsiveness observed for HCO<sub>3</sub><sup>–</sup>, demonstrating for the first time an encapsulation-induced emission property.