An ICT-Modulated strategy to construct colorimetric and ratiometric fluorescent sensor for mitochondria-targeted fluoride ion in cell living

Abstract A novel colorimetric and ratiometric fluorescent fluoride ion detecting system was been constructed base on ICT-modulated characteristic of the latent fluorophore, 7-(diethylamino)-3-(2-(pyridin-4-yl)vinyl)-coumarin and triisopropylsilane ether. The probe exhibited high selectivity and sensitivity detection of fluoride ion over other anion with a large emission wavelength shift (100 nm), and it also showed a low detection limit of 12 nM ( S / N  = 3). The sensing mechanism was investigated by NMR spectra, HRMS spectrometry and theoretical calculations. The results indicated the colorimetric and ratiometric response of the probe to fluoride ion was ascribed to the cleavage reaction of Si-O bond between triisopropylsilyl group and phenyl group by fluoride ion and induced the intermolecular charger transfer (ICT) process. By using the strategy, the probe has been successfully applied to detect mitochondrial fluoride ion in live cells by ratiometric fluorescence imaging, which demonstrated that the colorimetric and ratiometric fluorescence probe has promising applications for investigation of fluoride ion in biological samples.