An efficient fluorescence turn-on probe for Al3+ based on aggregation-induced emission

Abstract

Aggregation-induced emission (AIE) dyes show different emission mechanism from traditional dyes, which were found to be nonluminescent in the solution state and emissive in the aggregate state, and have been well employed to design turn-on fluorescent probes for various targets. In this paper, we report for the first time a tetraphenylethylene-based AIE probe 1 for Al³⁺, which employed two diethylenetriamine units as the recognition ligand for Al³⁺. In the presence of Al³⁺, a large fluorescence enhancement was achieved for probe 1, which together with the low background fluorescence of free probe 1 allow for high sensitivity for Al³⁺, with a dynamic range from 2.0 × 10⁻⁶ to 1.1 × 10⁻⁵ M observed, and a detection limit of 5 × 10⁻⁷ M for Al³⁺. The proposed probe shows high selectivity to Al³⁺. UV-vis absorption spectra experiments and dynamic light scattering measurements were performed to verify the AIE sensing mechanism of probe 1. Moreover, a 1 : 1 stoichiometry was estimated for the 1–Al³⁺ complex via fluorescence Job's method.