Hyo Jung Jang

A single colorimetric sensor for multiple targets: the sequential detection of Co2+ and cyanide and the selective detection of Cu2+ in aqueous solution

A new highly selective and multifunctional chemosensor 1 for the detection of Co2+, Cu2+ and CN−, based on 4-diethylaminosalicyl aldehyde and thiophene-2-carbohydrazide moieties, was designed and synthesized. 1 could simultaneously detect both Co2+ and Cu2+ by changing its color from colorless to yellow in aqueous solution. The binding modes of 1 to Co2+ and Cu2+ were determined to be a 2 : 1 complexation stoichiometry through job plot and ESI-mass spectrometry analysis. The detection limits (0.19 μM and 0.13 μM) of 1 for Co2+ and Cu2+ were lower than the DEP guideline (1.7 μM) of Co2+ and the WHO guideline (31.5 μM) of Cu2+ for drinking water. Importantly, 1 could detect and quantify Co2+ and Cu2+ in real water samples. Moreover, the resulting Co2+-2·1 complex sensed cyanide through naked-eye, showing recovery from Co2+-2·1 to 1. The sensing mechanisms of Cu2+ by 1 were explained by theoretical calculations.

A novel displacement-type colorimetric chemosensor for the detection of Cu2+ and GSH in aqueous solution

A new and simple colorimetric chemosensor 1 was developed for the sequential detection of Cu2+ and glutathione (GSH) in aqueous solution. Receptor 1 detected Cu2+ ions by changing its color from colorless to yellow. Based on UV-vis titrations, Job plot, and ESI-mass spectrometry analysis, the sensing mechanism for Cu2+ was proposed to be the enhancement of the intramolecular charge transfer band, which was further explained by theoretical calculations. The detection limit of 1 for Cu2+ (3.89 μM) was below the World Health Organization (WHO) guideline for drinking water (31.5 μM). Moreover, the resulting 1–Cu2+ complex could sequentially sense GSH, showing recovery of 1 from the complex.

A Multi-Responsive Naphthalimide-Based “Turn-on” Fluorescent Chemosensor for Sensitive Detection of Trivalent Cations Ga 3+ , Al 3+ and Cr 3+

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 (Ga3+, Al3+ and Cr3+). Sensor 1 detected and differentiated selectively trivalent metal ions Ga3+, Al3+ and Cr3+ by fluorescence enhancement at different emissions. The association constant of Ga3+-2∙1 complex is the highest one among those of the organic chemosensors reported, to date. The sensing mechanisms for Ga3+, Al3+ and Cr3+ were explained by UV-vis titrations, Job plots, ESI-mass analyses and theoretical calculations.