A novel coumarin-based chemosensor for colorimetric detection of Ag(I) ion and fluorogenic sensing of Ce(III) ion

A novel coumarin dye was synthesized, which acts as a chemosensor for selective detection of Ag+ and Ce3+ ions in aqueous solution. Upon addition of Ag+ to the sensor solution a new absorption band centered 580 nm was observed and the color of the solution changed from pale yellow to brown while other metal ions (Cu2+, Hg2+, Zn2+, Li+, Na+, Al3+, Fe3+, Co2+, Ni2+, K+ and Cr3+) did not cause distinct change. The coumarin dye can also be used as a fluorescence turn-on chemosensor for selective detection of Ce3+ over other metal ions including common trivalent metal ions Al3+, Fe3+ and Cr3+ as well as lanthanide metal ions Pr3+, Yb3+, Nd3+ and La3+. Investigation on changes in the intensity of the fluorescence emission band at around 350 nm with the equivalent ratio of Ce3+/sensor (0-1.1) reveals an approximate linear relationship, from which the concentration of Ce3+ ion may be estimated. The detection limit of Ce3+ ion by the sensor is estimated to be 2.07 × 10-7 M.