A versatile chemosensor 1 (E)-2-(((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)methylene)amino)-1H-benzo[de]isoquinoline-1,3(2H)-dione, based on naphthalimide and julolidine moieties, was developed for highly distinguishable and selective recognition of Group IIIA metal ions (Al3+, Ga3+ and In3+). Sensor 1 exhibited significant 'off-on' fluorescence responses at 488 nm in the presence of Al3+ and at 570 nm in the presence of Ga3+ and In3+. The same emission of Ga3+ and In3+ could be distinguished through different color changes (from colorless to yellow for Ga3+ and no color change for In3+). Binding constants of 1 for Ga3+ and In3+ are the highest reported to date for an organic chemosensor. A 2 : 1 binding mode between 1 with Al3+, Ga3+ and In3+ is proposed based on electrospray ionization mass spectrometry, Job plot analysis, and theoretical calculations.

A new highly selective and multifunctional chemosensor 1 for the detection of Co 2+ , Cu 2+ and CN À , based on 4-diethylaminosalicyl aldehyde and thiophene-2-carbohydrazide moieties, was designed and synthesized. 1 could simultaneously detect both Co 2+ and Cu 2+ by changing its color from colorless to yellow in aqueous solution. The binding modes of 1 to Co 2+ and Cu 2+ were determined to be a 2 : 1 complexation stoichiometry through job plot and ESI-mass spectrometry analysis. The detection limits (0.19 mM and 0.13 mM) of 1 for Co 2+ and Cu 2+ were lower than the DEP guideline (1.7 mM) of Co 2+ and the WHO guideline (31.5 mM) of Cu 2+ for drinking water. Importantly, 1 could detect and quantify Co 2+ and Cu 2+ in real water samples. Moreover, the resulting Co 2+ -2$1 complex sensed cyanide through naked-eye, showing recovery from Co 2+ -2$1 to 1. The sensing mechanisms of Cu 2+ by 1 were explained by theoretical calculations. Scheme 4 Proposed sensing mechanism of CN À by Co 2+ -2$1 complex. Fig. 10 (a) Absorption spectral changes of competitive selectivity of Co 2+ -2$1 complex (20 mM) toward CN À (30 equiv.) in the presence of other anions (30 equiv.) in bis-tris buffer/DMSO (95/5, v/v). (b) The color changes of competitive selectivity of Co 2+ -2$1 complex (20 mM) toward CN À (30 equiv.) in the presence of other anions (30 equiv.).This journal is

We report a new sensor, 1, for sequentially detecting Zn 2+ and CN − based on fluorescence. Sensor 1 was prepared through the reaction of 3-aminobenzofuran-2-carboxamide with 4diethylaminosalicylaldehyde. Sensor 1 showed a selective "off−on" fluorescent response toward Zn 2+ , distinguishing Zn 2+ from Cd 2+ . The limit of 1 (0.35 μM) for monitoring Zn 2+ is lower than the World Health Organization (WHO) guideline (76 μM) for water available for drinking. Importantly, sensor 1 could sense Zn 2+ in living cells and aqueous media. In addition, the resulting 1−Zn 2+ complex functioned as an efficient "on−off" sensor for CN − . The mechanisms of 1 for detecting Zn 2+ and CN − were explained by spectroscopic, spectrometric, and theoretical studies.

A new multifunctional chemosensor 1, (E)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)-1H-benzo[de]isoquinoline-1,3(2H)-dione, based on naphtalimide and naphthaldehyde was developed, which showed the fluorescence responses to trivalent metal ions (Ga, Al and Cr). Sensor 1 detected and differentiated selectively trivalent metal ions Ga, Al and Cr by fluorescence enhancement at different emissions. The association constant of Ga-2∙1 complex is the highest one among those of the organic chemosensors reported, to date. The sensing mechanisms for Ga, Al and Cr were explained by UV-vis titrations, Job plots, ESI-mass analyses and theoretical calculations.

A new selective and sensitive chemosensor1for the sequential detection of Cu2+and GSHvianaked-eye has been developed.