Highly selective on-off fluorescence recognition of Fe3+ based on a coumarin derivative and its application in live-cell imaging.

A novel coumarin chemosensor, 7-hydroxy-2-oxo-N-(pyridin-2-ylmethyl)chromene-3-carboxamide (Probe 1), demonstrated significant selectivity towards Fe3+ ions. Probe 1 exhibited high fluorescence emission profile at 447nm, excellent selectivity towards Fe3+ over other biologically important metal ions (Al3+, Ba2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ and Sn2+). Interestingly, there was ~30-fold decrease in fluorescence intensity upon Fe3+ binding. The limit of detection of Fe3+ was found to be 0.76μM (~40ppb). Probe 1 also exhibited high potential as an intracellular chemosensor for Fe3+.