Halogen Bonding Tetraphenylethene Anion Receptors: Anion-Induced Emissive Aggregates and Photoswitchable Recognition

A series of tetraphenylethene (TPE) derivatives functionalized with highly potent electron-deficient perfluoroaryl iodo-triazole halogen bond (XB) donors for anion recognition are reported. (HNMR)-H-1 titration experiments, fluorescence spectroscopy, dynamic light scattering measurements, TEM imaging and X-ray crystal structure analysis reveal that the tetra-substituted halogen bonding receptor forms luminescent nanoscale aggregates, the formation of which is driven by XB-mediated anion coordination. This anion-coordination-induced aggregation effect serves as a powerful sensory mechanism, capable of luminescence chloride sensing at parts per billion concentration. Furthermore, the doubly substituted geometric isomers act as unprecedented photoswitchable XB donor anion receptors, where the composition of the photostationary state can be modulated by the presence of a coordinating halide anion.

Automated summary

A series of TPE derivatives functionalized with perfluoroaryl iodo-triazole halogen bond donors have been reported for anion recognition. These derivatives form luminescent nanoscale aggregates driven by anion coordination, serving as a powerful sensory mechanism for parts per billion concentration chloride sensing. The geometric isomers of these derivatives also act as unprecedented photoswitchable XB donor anion receptors, with the photostationary state composition modulated by the presence of a coordinating halide anion.