A new colorimetric, near-infrared fluorescent probe for rapid detection of palladium with high sensitivity and selectivity

A new type of colorimetric, fluorescent probe capable of palladium (Pd0) sensing with beaconing fluorescence signal in the quiet near-infrared (NIR) region, recognition response time of approximately 3 min, limit of detection (LOD) down to 5.1 ppb, and excellent recognition specificity over a wide range of interfering metal cations was developed. Such type of probe underwent sequential Pd0-mediated oxidative addition reaction and reduction elimination reaction, which yielded typical A-π-D-π-A molecular skeleton of the final reation product with markedly facilitated ICT processes. The Pd0-mediated conversion from the probe to the reaction product generated distinct color change from light yellow to dark blue and typical turn-on NIR fluorescence signal with fluorescence on-to-off contrast up to 80 times. Such type of feature-packed probe is expected to further advance Pd sensing capability in pharmacy and biomedical engineering applications.296