Novel AIEgens with a 3,5-dibromobenzaldehyde skeleton: molecular design, synthesis, tunable emission and detection application

In this study, three novel fluorophores with aggregation-induced emission effects (AIE) have been synthesized by a new strategy that uses the non-AIE active compound 3,5-dibromobenzaldehyde (DBB) as a core (stator). This new strategy is completely different from the traditional synthetic process of AIE compounds that rely heavily on the modification of the classic existing AIE core such as archetypal silole, tetraphenylethene and distyrylanthracene. The obtained DBB derivatives (S1, S2 and S3) display typical AIE characteristics in which their quantum yields in the solid state are much higher than that in the solution. In addition, the emission can be fine-tuned by varying the rotor on the DBB skeleton, and a significant Stokes shift from 395 nm to 434 nm can be observed with the increase of the conjugate structure from S1 to S3. Furthermore, S1, S2 and S3 showed an exclusively selective turn-on response to As3+, and the detection limits are lower than the guideline of As3+ in drinking water, permitted by the EPA. This study will be instructive in providing a strategy for the synthesis of AIE luminogens, which not only greatly enrich the species of AIE compounds, but also broaden their application.