This work reports two new diketoprrrolopyrrole-based fluorescent chemosensors (DPP-Py1 and DPP-Py2) using symmetrical diamides as recognition groups for selective and fast detection of citrate in the near-infrared region. To our delight, DPP-Py1 is a ratiometric sensor, whereas DPP-Py2 is a turn-on fluorescent sensor. It is worth noting that DPP-Py1 has higher accuracy and sensitivity with a relatively lower detection limit (1.8 × 10(-7) M) and better stability in different pH buffers than DPP-Py2. Scanning electron microscopy, dynamic light scattering analyses, (1)H NMR titration, and 2D-NOESY NMR suggested that the fluorescence increment of the probes DPP-Py1 and DPP-Py2 for citrate could probably originate from aggregation-induced emission (AIE) on the basis of the complexation of the pyridinium-based symmetrical diamides, DPPs, with carboxyl anions of citrate. Our work may provide a simpler and faster means for qualitative and quantitative analysis of citrate through an AIE mechanism.

No abstract

No abstract

No abstract

A new fluorescence light-up probe (DTPA-TPY-Zn) for citrate detection has been developed by integrating an AIE motif (DTPA-TPY) with Zn2+, which can detect citrate via a one-step straightforward assay with excellent sensitivity and selectivity.