Protonation regulates intermolecular interaction force to achieve reversible ACQ-AIE conversion

In recent years, there has been a lot of focus on aggregation-induced emission materials, and most of the research has focused on the unidirectional conversion from ACQ (aggregation-causing quenching) to AIE (aggregation-induced emission), which inevitably requires complex chemical synthesis and cumbersome processes, and molecules with reversible ACQ and AIE conversion characteristics are rarely reported. In order to achieve a reversible conversion based on a single material between ACQ and AIE properties, we have developed a new functional material , DBPZ-2 (1,4-bis((4-(benzo[c] (Li et al., 2020; Hu et al., 2014; Song et al., 2024) [1,2,5]thiadiazol-4-yl)piperazin-1-yl)methyl)benzene). This compound exhibits AIE properties under neutral conditions, and interestingly, it exhibits significant ACQ properties when protonated, and then restores AIE properties after simple deprotonation . Furthermore, the sensitive response of DBPZ-2 to pH can be used as a fluorescent probe to monitor the changes in the pH value of cellular lysosomes , which brings hopes for future research on lysosomal biology and related diseases.