A highly turn-on fluorescent CHEF-type chemosensor for selective detection of Cu in aqueous media.

An efficient "turn on" fluorescence chemosensor Schiff base LH based on the combination of 2-Hydroxy-5-(p-tolyldiazenyl)benzaldehyde and N-(3-Aminopropyl)imidazole was prepared and characterized then evaluated for its selective fluorescent sensing of Cu amongst other metal ions. The CN isomerization inhibition process induced by the Cu binding warrants the chelation-induced enhanced fluorescence (CHEF) effect. In addition, the detection limit sensing of LH for Cu was found to be 1.8 × 10 M that is below the WHO recommendation level (20 μM) for drinking water.