An AIE and ESIPT active Schiff base as colorimetric probe of Fe³⁺ and turn-on fluorescent probe of Al³⁺: Experimental and theoretical studies

In this present study, a simple cation chemoprobe 1 bearing naphthol O–H and imine group was designed and synthesized, which was identified as an aggregation induced emission (AIE) active molecule with excited state intramolecular proton transfer (ESIPT) features. In addition, 1 showed both colorimetric detection for Fe³⁺ and turn-on fluorescence response for Al³⁺. The binding ratio of 1 to Fe³⁺ and Al³⁺ were determined both to be 1:1 via Job's plot and ESI-mass spectrometry analysis. The limit of detection (LOD) of probe 1 to Fe³⁺ and Al³⁺ were 0.10 and 0.43 μM, respectively. Moreover, probe 1 could be used to quantify Fe³⁺ and Al³⁺ in environmental water samples.