Coumarin–indanedione conjugate as a doubly activated Michael addition type probe for the colorimetric and ratiometric fluorescent detection of cyanide

A coumarin–indanedione conjugate as an activated Michael addition type probe was prepared for cyanide ion detection. The colorimetric and ratiometric fluorescent response of the probe to cyanide ion is due to the Michael addition of cyanide to the doubly activated Michael receptor of the probe which blocks an intramolecular charge transfer process. The probe displays a fast response to cyanide ion at room temperature, and a maximal ratiometric fluorescent signal is achieved in the presence of only 2 equivalents of cyanide ion. Moreover, competitive species did not induce any significant changes both in color and emission intensity ratio (I485/I609), demonstrating the high selectivity of the probe to cyanide.

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► A coumarin–indanedione conjugate was prepared for CN− detection.
► It exhibits ratiometric fluorescent response to CN− due to the Michael addition.
► High selectivity and sensitivity for detecting CN− are noted for this system.