Quinoline-based colorimetric chemosensor for Cu2+: Cu2+-induced deprotonation leading to color change

Abstract

Abstract A quinoline-based colorimetric chemosensor (QDB) for Cu 2+ was synthesized by coupling quinoline-2-carbaldehyde with 4-(dimethylamino)benzohydrazide. Although most transition metal cations can cause redshifts in the UV–vis spectrum of QDB, the response of the chemosensor for Cu 2+ can be easily distinguished because it exhibits the largest redshift together with a color change from colorless to red in response to Cu 2+ . Other metal ions have no effect on the specific response of QDB to Cu 2+ . The significant redshift and color change were attributed to Cu 2+ -induced deprotonation of NH in the sensor.