Research PaperA pyridinyl-organoboron complex as dual functional chemosensor for mercury ions and gaseous acid/base

- A novel pyridinyl-organoboron complex POB has been designed and synthesized.
- Complex POB exhibited high fluorescence quantum yields in both monomer and aggregation state.
- POB exhibited a ratiometric chemosensor to detect Hg2+ with high sensitivity, selectivity and rapid dynamic, which can be visualized by naked eyes from cyan to green.
- POB film can be used for the visual detection of gaseous acid in atmosphere.

Recently, most of fluorescent sensors have been focused on in diluted solutions because π-π stacking of traditional fluorescent materials would quench their emissions in solid state, and meanwhile some fluorescent materials in aggregation were reported as chemosensors to detect target analytes although they always were involved in photonic and electronic devices. Fluorescent probes in both the diluted solutions and aggregation have scarcely been developed in reported works. In this study, we report a novel pyridinyl-organoboron complex as a probe to detect mercury ions (Hg2+) in diluted solution and gaseous acid/base in aggregation. The as-synthesized probe with strong fluorescence contained a pyridine unit, as the reactive site of both Hg2+ and gaseous acid in the environmental monitoring. Upon the addition of Hg2+, the fluorescence ratio of I480/I515 was changed immediately accompanying with the color variation from cyan to green under a UV lamp. On the other hand, the complex probe was prepared as a film on a glass pallet for the detection of gaseous acid with the emissive color evolution from yellow to orange-red. Interestingly, the film sensor for acid/base gas had a reversible property with 10 cycles at least due to its much higher photostability.

A pyridinyl-organoboron complex is an excellent fluorescent sensor of Hg2+ with high sensitivity, selectivity and rapid dynamics. Meanwhile, the film of complex can be used for the visual detection of gaseous acid in atmosphere.186