Coumarin Spiropyran Dyad with a Hydrogenated Pyran Moiety for Rapid, Selective, and Sensitive Fluorometric Detection of Cyanide Anion.
We synthesized a coumarin spiropyran dyad with a hydrogenated pyran moiety (2) behaving as an off on type fluorescent receptor for rapid, selective, and sensitive detection of cyanide anion (CN( in aqueous media. The receptor itself shows almost no fluorescence with a quantum yield 0.01, due to the delocalization of p electrons over the molecule. Selective nucleophilic addition of CN( to the spirocarbon of the molecule rapidly promotes spirocycle opening within only 3 min. This leads to localization of p electrons on the coumarin moiety and exhibits strong light blue fluorescence at 459 nm with very high quantum yield (0.52) As a result of this, the receptor facilitates rapid, selective, and sensitive fluorometric detection of CN( as low as 1.0 mM.
Analytical chemistry