Dimethoxy triarylamine-derived terpyridine–zinc complex: a fluorescence light-up sensor for citrate detection based on aggregation-induced emission

Abstract

Citrate is a vital metabolite in the Krebs cycle of nearly every aerobic cell. The abnormality in its levels in biological systems is closely associated with some diseases. Facile and efficient approaches for citrate recognition and quantification are thus in great demand. In this paper, a new sensitive and highly selective fluorescence light-up sensor (DTPA-TPY-Zn) for citrate detection has been developed by integrating an AIE motif (DTPA-TPY) with Zn²⁺. This probe can detect citrate in a fast and simple way by a one-step straightforward assay. It shows significant fluorescence enhancement with a relatively low detection limit (3.5 × 10⁻⁷ M). The fluorescence turn-on mechanism is ascribed to the complexation of DTPA-TPY-Zn with citrate as well as the aggregation-induced emission (AIE) properties of dimethoxy triarylamine-terpyridine (DTPA-TPY), which is confirmed using the ¹H NMR and mass spectra (MS), scanning electronic microscopy and dynamic light scattering measurements. In addition, the quantification of citrate in urine makes DTPA-TPY-Zn an effective fluorometric probe for the citrate detection in real samples.