Dyes based on the 2(1H)‐quinolone skeleton as potential colorimetric and fluorescent sensors for cyanide anions

The sensing properties of dyes based on 2(1H) quinolones containing dicyanoethylene groups towards selected anions such as CN^?, F^?, I^?, Cl^?, SCN^?, CH₃COO^?, and were evaluated. The spectroscopic responses of these compounds were investigated in a solution of acetonitrile/water (1:9, v/v) and phosphate buffer at a pH of 7.4. These dyes were found to act as efficient colorimetric and high turn–off fluorescent sensors to cyanide anions. The fluorescence intensity was linearly related to the concentration of CN^? from 1 to 10 µmol/L, and the detection limits reached a micromolar level of 6.7, 11.1, 3.8 and 7.2 µmol/L for 1‐4 , respectively. The cytotoxic effect of the dyes against human neuroblastoma cells (SH‐SY5Y) was also determined by MTT assay. The examined compounds exhibited slight cytotoxicity against cells under experimental conditions.