A novel benzophenone-based colorimetric chemosensor for detecting $$\hbox {Cu}^{2+ }$$ Cu 2 + and $$\hbox {F}^{-}$$ F -

Abstract

A novel selective colorimetric chemosensor ANBP ((E)-(2-(((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)methylene)amino)-5-nitrophenyl)(phenyl)methanone), based on the combination of benzophenone group and julolidine chromophore, was synthesized. Sensor ANBP showed rapid colorimetric responses toward $$\hbox {Cu}^{2+}$$ (pale orange to pink) and $$\hbox {F}^{-}$$ (orange to blue). The detection limit by ANBP to $$\hbox {Cu}^{2+}$$ (6.82 $$\upmu $$ M) was far below WHO guideline value (31.3 $$\upmu $$ M). Moreover, ANBP could quantify $$\hbox {Cu}^{2+}$$ in aqueous samples. 1:1 binding mode between ANBP and $$\hbox {Cu}^{2+}$$ or $$\hbox {F}^{-}$$ was proposed by ESI-mass analyses and Job plots. The remarkable color changes with $$\hbox {Cu}^{2+}$$ and $$\hbox {F}^{-}$$ resulted from the intramolecular charge transfer (ICT) effect, which was demonstrated by theoretical calculations. A novel selective colorimetric chemosensor ANBP, based on the combination of benzophenone group and julolidine chromophore, was designed and synthesized. Sensor ANBP showed rapid colorimetric responses toward $$\hbox {Cu}^{2+}$$ (pale orange to pink) and $$\hbox {F}^{-}$$ (orange to blue).