Coumarin-Cu(II) ensemble-based cyanide sensing chemodosimeter.
ABSTRACT An "ensemble"-based chemodosimeter 1-Cu(II) for cyanide detection is reported. 1-Cu(II) can recognize a cyanide ion over other anionic species to show a marked fluorescence enhancement under aqueous conditions. "Off-on" fluorescence change of 1-Cu(II) is proceeded by addition of cyanide, which induces decomplexation of the Cu(II) ion from nonfluorescent 1 followed by hydrolytic cleavage of the resulted Schiff base to give a strongly fluorescent coumarinaldehyde (2). The selective detection of cyanide with 1-Cu(II) for biological application was also performed in HepG2 cells.
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ABSTRACT: Benzimidazoles derived from lactic acid and mandelic acids were employed as photosignaling synthons to construct 15-C-5 azacrowns 3 & 4 with difference in electronic environments at the carbon attached to 2-position. These receptors were used as probes for cation sensing using UV–vis and fluorescence titration techniques. Although both the receptors have identical macrocyclic backbone and are found selective for Cu2+, receptor 3 displayed stronger binding towards Cu2+ in comparison to 4. The addition of Cu2+ to the probes 3 & 4 in solution caused quenching of fluorescence. The results clearly indicate that the stability of Cu2+ complexes of 3 and 4 depends on different factors. The association constant, KSV for 3 with Cu2+ was (1.53 x10^5 M-1) an order higher than that exhibited by 4 for Cu2+ (9.27 x 10^4 M-1).Journal of inclusion phenomena and macrocyclic chemistry 09/2014; · 1.17 Impact Factor
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ABSTRACT: Herein, two compounds (1 a and 1 b) were rationally constructed as novel reaction-based fluorescent probes for CN(-) by making use of the electron-withdrawing ability of the cyano group that was formed from the sensing reaction. Notably, this design strategy was first employed for the development of fluorescent CN(-) probes. The experimental details showed that probe 1 a exhibited a fluorescence turn-on response to CN(-) , whereas other anions, biological thiols, and hydrogen sulfide gave almost no interference. The detection limit of probe 1 a for CN(-) was found to be 0.12 μM. The sensing reaction product of 1 a with CN(-) was characterized by NMR spectroscopy and mass spectrometry. TD-DFT calculations demonstrated that the formed cyano group drives the intramolecular charge transfer (ICT) process from coumarin dye to the cyano group and thus the original strong ICT from the coumarin dye to the 3-position pyridyl vinyl ketone substituent is weakened, which results in recovery of coumarin fluorescence. The practical utility of 1 a was also examined. By fabricating paper strips, probe 1 a can be used as a simple tool to detect CN(-) in field measurements. Moreover, probe 1 a has been successfully applied for quantitative detection of endogenous CN(-) from cassava root.Chemistry - An Asian Journal 08/2014; · 4.57 Impact Factor
Dataset: Copper Sensor