Abstracts

Chiral film-based fluorescent sensors are promising candidates for chiral discrimination of enantiomers because of their miniaturization and low power consumption. However, their practical application is limited by the contradiction between enantioselectivity and the adsorption capability of chiral films. The construction of hierarchically porous structures in crystalline microporous materials is considered to be an effective way to improve mass transfer and accessibility of the active sites, and this provides a solution to resolve the contradiction. By use of a dielectric barrier discharge reactor, we developed a facile strategy for the fabrication of crystalline chiral metal-organic framework (CMOF)-based films with inherent microporosity and template-induced, homogeneously distributed, and macroporous structures. This method was successfully applied to obtaining various CMOF-based thin films with interconnected macro-microporous structures. The as-synthesized films preserve chiral nature, high crystallinity, high specific surface area, and strong fluorescence emission. When L-histidine (L-His) moieties were introduced into the MOF backbone, ordered macroporous L-His-ZIF-8 film was produced to form a fluorescent sensor for various chiral alcohols. Compared to the purely microporous L-His-ZIF-8 film, the resultant hierarchical porous film exhibited a higher enantioselectivity and better detectability.