A simple colorimetric and fluorometric probe for rapid detection of CN^- with large emission shift

In this work, a novel probe R was synthesized via Knoevenagel reaction between 3H-benzo[f]chromium-2-formaldehyde and ethyl cyanoacetate for selective detection of CN^- in both colorimetric and fluorescent signal channels. The recognition of CN^- was through the nucleophilic reaction of CN^- to C = C of probe R, which destroys π-conjugation and blocks the ICT effect of the probe, resulting in colorimetric and fluorometric responses. Probe R showed great sensitivity toward CN^-, with large fluorescent emission (595 nm) and low detection limit (0.70 μM). Moreover, probe R can detect exogenous CN^- in living cells.