Fluorescence signaling of BF3 species by transformation of an ESIPT dye to its difluoroboron adduct

- The BF3-selective probe was developed using BF2 adduct formation with an ESIPT dye.
- Fluorescence sensing of BF3 species was possible with a detection limit of 87 nM.
- Polymeric dye prepared by RAFT copolymerization was used for practical application.
- Using a polymer-coated test strip, BF3 signaling in the gaseous state was possible.

New selective and sensitive probes were developed for signaling chemically and industrially important, but toxic, BF3 species. These probes utilize the transformation of 2-(2-hydroxyphenyl)benzothiazole derivatives into their boron difluoride adducts. Benzothiazole-based probes demonstrated significant off-on fluorescence enhancement (I/I0 > 2000) in the presence of BF3 species in acetonitrile. The BF3 signaling was nearly instantaneous and completed within less than 1 min. Furthermore, interference from possible BF3 decomposition contaminants, such as boric acid, HF, and BF4−, was not observed. A dye-immobilized polymer, prepared by RAFT copolymerization of dye-derived acrylamide monomer with methyl methacrylate, was successfully used for the signaling of BF3 species with a detection limit of 8.7 × 10−8 M. These probes could be useful for the sensitive and selective fluorescent detection of important but toxic BF3 species in chemical and industrial applications.

Prominent fluorescence signaling probe for BF3 species has been developed using a selective BF2 adduct formation with an ESIPT dye. Polymeric dye, prepared by RAFT polymerization, showed markedly sensitive signaling behavior for BF3 species in solution and when coated onto paper test strips.167