From aggregation to detection: AIEgen-based sensors for fluoride and cyanide monitoring

Aggregation-induced emission luminogens (AIEgens) have emerged as promising platforms for sensing applications owing to their distinctive fluorescence enhancement in the aggregated state. This review highlights recent advances in AIEgen-based sensors for the selective and sensitive detection of fluoride (F^-) and cyanide (CN^-) ions, both of which pose significant environmental and health concerns. The design strategies focus on incorporation of specific recognition units, such as hydrogen-bond donors and electrophilic centers, into AIE-active frameworks to achieve high selectivity. The sensing mechanisms for fluoride are primarily governed by hydrogen bonding or deprotonation mechanisms, whereas cyanide detection often involves nucleophilic addition reactions that induce distinct photophysical changes. In this review, we summarize some representative advances in AIEgen-based sensors for anion recognition through different sensing mechanisms, such as deprotonation or hydrogen bonding, nucleophilic addition, Lewis acid-base interactions, etc., reported in recent years. We believe that this review on host-guest anion recognition using AIEgens will provide guidance for the rational design and preparation of advanced functional sensors for real-time anion recognition with promising practical applications.