A red fluorescent turn-on chemosensor for Al3+ based on a dimethoxy triphenylamine benzothiadiazole derivative with aggregation-induced emission
Aluminum is a known neurotoxin to organisms and believed to cause Alzheimer's disease, osteomalacia, and breast cancer. Therefore, effective tools for Al3+ recognition are in great demand. In this study, a new, sensitive, and highly selective red turn-on chemosensor (TB-COOH) for Al3+ was prepared by combining the dimethoxy triarylamine benzothiadiazole motif and carboxyl group, where the benzothiadiazole derivative functioned as an aggregation-induced emission (AIE) moiety and the carboxyl motif functioned as the recognition site for Al3+. This chemosensor showed significant fluorescence enhancement upon selective addition of Al3+ and a relatively low detection limit (1.5 × 10−7 M). The fluorescence turn-on mechanism was ascribed to the aggregation of TB-COOH after complexation with Al3+, which was confirmed by 1H NMR and FT-IR spectroscopies and scanning electronic microscopy. Furthermore, benefiting from its good water solubility and biocompatibility, imaging detection and real-time monitoring of Al3+ in living HeLa cells were successfully achieved.