Addition of α-Cyanomethylpyridine to Naphthalimide via Trifluoromethyl-Directed CH Functionalization: Cyanide Sensing in Aqueous Media.

A colorimetric anion sensor based on the activated C-H group is described, and the selective and reusable detection of cyanide using the sensor is demonstrated. The system uses bromine to block isomerization and trifluoromethyl-directed C-H regioselective functionalization for direct C-C bond formation between a fluorophore and 2-(pyridin-2-yl)acetonitrile. Thus, this system provides a new way to develop activated CH-based anion receptors.