Colorimetric and turn-on fluorescent chemosensor with large stokes shift for sensitively probing cyanide anion in real samples and living systems.

Cyanide anion is a ubiquitous chemical substance in the ecosystem, however, human daily life is severely threatened by its toxicity at any time. In this paper, a novel colorimetric and turn-on chemosensor 4-(4-(2,2-difluoro-6-methyl-2H-1,3,2-dioxaborinin-4-yl)buta-1,3-dien-1-yl)-N,N-dimethylaniline (NBF) for detecting cyanide anion was synthesized based on the 4-(dimethylamino)cinnamaldehyde and β-diketone difluoroboron complex. This fluorescent probe exhibited excellent spectroscopy properties such as large stokes shift, long emission wavelength, and good sensitivity. The detection limit of NBF towards cyanide ion was determined as low as 2.23 μM. Additionally, the detection mechanism towards cyanide ion was confirmed to be the nucleophilic addition interaction by high resolution mass spectrum (HRMS), 1H Nuclear Magnetic Resonance (NMR) titration, and quantum chemistry theory calculation. In addition, the probe NBF had been successfully utilized in detecting cyanide ions in water and food samples as well as imaging in the biological system, which broadened its practical application prospects.