A novel benzophenone-based colorimetric chemosensor for detecting Cu ^{2 +} and 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 Cu ^{2 +} (pale orange to pink) and F ^- (orange to blue). The detection limit by ANBP to Cu ^{2 +} (6.82 μ M) was far below WHO guideline value (31.3 μ M). Moreover, ANBP could quantify Cu ^{2 +} in aqueous samples. 1:1 binding mode between ANBP and Cu ^{2 +} or F ^- was proposed by ESI-mass analyses and Job plots. The remarkable color changes with Cu ^{2 +} and F ^- resulted from the intramolecular charge transfer (ICT) effect, which was demonstrated by theoretical calculations. Graphical abstract: 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 Cu ^{2 +} (pale orange to pink) and F ^- (orange to blue). [Figure not available: see fulltext.]