A novel 'turn-on' fluorescent probe based on triphenylimidazole-hemicyanine dyad for colorimetric detection of CN~- in 100% aqueous solution

摘要

Graphical abstractDisplay OmittedHighlights•A novel “turn-on” fluorescent probe based on triphenylimidazole and hemicyanine dyad was synthesized for CN−detection.•The probe exhibited colorimetric and fluorescent dual responses with CN−in 100% aqueous solution.•The detection limit was down to 20.6nM in 100% aqueous solution.•The probe has been successfully used to determine CN−in real water as well as to image CN−in living cells.AbstractA new colorimetric fluorescent probe (MCy) for CN−is designed and synthesized based on triphenylimidazole-hemicyanine dyad. The probe shows high selectivity towards CN−in 100% aqueous solution even in the presence of other competitive anions such as F−, Cl−, AcO−, NO2−, H2PO4−, I−, SCN−, SO42−, NO3−, HCO3−, Br−and S2−. Upon nucleophilic addition of CN−to the indolium group, the probe displays large blue-shift in UV–vis spectrum and remarkable “turn-on” fluorescence owing to the disruption of intramolecular charge transfer. Meanwhile, the probe also undergoes a naked-eye discernible color change from orange to light pink in the sunlight as well as an obvious fluorescence color change from non-emissive to bright blue under a UV lamp. The detection limit of CN−in aqueous solution can be as low as 20.6nM, which is much lower than the permissible level of CN−in drinking water according to the WHO. In addition, the probe has been successfully used to determine CN−in real water samples as well as to fabricate test paper kit for CN−detection.