Novel azo-dye quinazolinones as colorimetric chemosensors for detection of cobalt and ferrous ions in aqueous medium

Highly efficient azo-day quinazolinone derivatives carrying a π bond and OH electron donor groups have been designed, synthesized, and evaluated as colorimetric chemosensors for detecting metal ions in biological and environmental samples, which was further supported by the DFT studies and UV–vis titration experiment. The 3-amino-2-styrylquinazolin-4(3H)-one (1) was directed to react with phenols during a diazotization type reaction to form a series of azo-day 3-(diazenyl)-2-(styryl)quinazolin-4(3H)-one (4a-e), which could not only have been confirmed by FTIR, H1NMR, C13NMR, Ms and elemental analysis but could also be easily used for the detection of metal ions. Compound 4c exhibited a rapid qualitative and quantitative method for the detection of CoII at λ max (582 nm) and FeII at λ max (566 nm) in an aqueous solution. The current study introduces a facile, low cost, more specific and selective chemosensor for detecting trace amounts of cobalt and ferrous ions.