A unique AIE multi-responsive half-salamo-like fluorescence sensor for temperature, pH and Cu2+/S2- ions in aqueous media

A novel multi-stimulus responsive small molecule fluorescent sensor DHS was developed. DHS with solvent-dependent properties exhibited active AIE effects, which is rare in salamo-like compounds. DHS has an excellent reversible thermal response and pH fluorescence response under various external stimuli (temperature and acid-base conditions). The response mechanism is supported by relevant studies and theoretical calculations. In addition, DHS can be used as a highly selective and sensitive fluorescent probe for the sequential detection of Cu2+ and S2– in water. DHS exhibits very prominent detection limit (48.59 nM) for Cu2+, which is superior to most small molecule fluorescent sensors of the same type. The experiments showed that the sensor DHS can be used for the ions detection in portable test strips and actual water samples. This study reveals a new strategy for the construction of salamo-like compounds with AIE properties, which can be beneficial for research in the fields of temperature sensing, acidity detection and ion recognition.