A novel coumarin chalcone derivative 1 was designed, synthesized and characterized by nuclear magnetic resonance spectra and high resolution mass spectrum. The photophysical and recognition properties of the compound as red fluorescent probe for cyanide and biothiols including cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) have been discussed systematically. Red fluorescence probe 1 was able to achieve rapid and selective identification for cyanide anion and biothiols in aqueous solutions with red fluorescence quench. In addition, the recognition mechanism of 1 was demonstrated by in situ 1H NMR. The compound has two potential nucleophilic sensing sites including carbon-carbon double bond and 4-position of coumarin. The results indicate that cyanide anions can be bonded to these two sites to afford 2:1 bonding product. But biothiols only are bonded to carbon-carbon double bond by Michael addition reaction. The bonding of both cyanide and biothiols to the probe disrupts intramolecular charge transfer and leads to fluorescence quench.
Coumarins Cyanides