Fluorometric detection of Cu2+ and Ni2+ by a quinoline-based glucopyranose derivative via the excimer of quinoline subunit

Abstract Triazole-appended quinoline and naphthyl-based fluorescent sensors 1 and 2 have been developed from D-glucose. The quinoline-based sensor 1 exhibited excimer emission whereas model compound 2 did not exhibit any excimer emission in MeOH/H2O (7/3, v/v). The excimer emission of quinoline moiety was quenched in the presence of Cu2+ and Ni2+ ions in an aqueous methanolic solution. The sensing ability of sensor 1 for Cu2+ and Ni2+ ions was also established by absorption spectroscopy. Interestingly, sensor 1 exhibited 1:1 stoichiometric ratios for both ions which were further supported by mass spectra of the complexes. The limit of detection (LOD) values of 1 for Cu2+ and Ni2+ were determined as 1.01 µM and 1.46 µM respectively. To the best of our knowledge, this is the first example of a monoquinoline-based sensor that exhibited excimer quenching in the presence of Cu2+ and Ni2+ ions.