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Herein, a hydrazine-based chromogenic, fluorogenic and electrochemical chemosensor BCC [1,5-bis(4-cyanophenyl) carbonohydrazide] was premeditated and synthesized through a simple one-step synthetic procedure for the selective detection of toxic anions, such as F-, in a DMSO-ACN medium and cations, such as Hg2+ and Cu2+, in a MeOH-water medium. The detection limit for F- was reckoned to be 0.5 ppm, and for Hg2+ and Cu2+, it was 0.8 ppm and 50 nM, respectively. The chemosensor exhibited a distinct change in colour from colourless to dark blue in the presence of F-, and upon the addition of Hg2+ and Cu2+, the BCC turned from colourless to light blue and purple accordingly. Moreover, turn-on fluorescence response transpired by the attenuation of PET signified the selective sensing of analytes with a zero-order rate constant. Sophisticated analytical experiments, such as ESI-MS, UV-Vis, photoluminescence, cyclic voltammetry, FTIR, and 1H-NMR, along with the theoretical calculations corroborated the probable sensing pathways. The reversible colorimetric response of BCC towards F- and H+ can be advantageous in the design of electronic circuits derived from Boolean algebra. The complexation ability of the sensor with toxic Hg2+- and Cu2+-like ions made it an efficient material to remove these metal ions from real water sources polluted with these toxic elemental ions. Furthermore, the in vitro studies were accomplished using the Bauhinia acuminate pollen cell to check the cell penetrability of the sensor molecule.

Rhodamine-thiophene conjugate (L) has been synthesized and characterized by (1)H NMR, FTIR and mass spectra. L shows a large enhancement in emission intensity in presence of Hg(2+). Moreover, naked eye color of L becomes intense red in presence of Hg(2+). The lowest detection limit for Hg(2+) is 1 × 10(-9)M in HEPES buffer (0.1M in EtOH/water, 1/1, v/v, pH 7.4). Hg(2+) induced chelation enhanced fluorescence (CHEF) is associated with spirolacram ring opening of the rhodamine unit. Trace level intracellular Hg(2+) is visualized under fluorescence microscope., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A carbazole-thiosemicarbazone-Hg(2+) ensemble-based fluorogenic probe for detection of iodide in aqueous media is reported. The first fluorescent sensor for iodide anions was constructed based on the displacement approach. An 'ensemble' is able to selectively sense iodide over other anions followed by the release of 9-(butane-1-yl)-9H-carbazole-3,6-dihydrazinecarbothioamide to give a remarkable change of fluorescence turn-on signal at pH 7.4 under aqueous media. The practical use of an 'ensemble' was demonstrated by its application to the detection of iodide in the living cells.

Herein, a hydrazine-based chromogenic, fluorogenic and electrochemical chemosensor BCC [1,5-bis(4-cyanophenyl) carbonohydrazide] was premeditated and synthesized through a simple one-step synthetic procedure for the selective detection of toxic anions, such as F−, in a DMSO–ACN medium and cations, such as Hg2+ and Cu2+, in a MeOH–water medium. The detection limit for F− was reckoned to be 0.5 ppm, and for Hg2+ and Cu2+, it was 0.8 ppm and 50 nM, respectively. The chemosensor exhibited a distinct change in colour from colourless to dark blue in the presence of F−, and upon the addition of Hg2+ and Cu2+, the BCC turned from colourless to light blue and purple accordingly. Moreover, turn-on fluorescence response transpired by the attenuation of PET signified the selective sensing of analytes with a zero-order rate constant. Sophisticated analytical experiments, such as ESI-MS, UV-Vis, photoluminescence, cyclic voltammetry, FTIR, and 1H-NMR, along with the theoretical calculations corroborated the probable sensing pathways. The reversible colorimetric response of BCC towards F− and H+ can be advantageous in the design of electronic circuits derived from Boolean algebra. The complexation ability of the sensor with toxic Hg2+- and Cu2+-like ions made it an efficient material to remove these metal ions from real water sources polluted with these toxic elemental ions. Furthermore, the in vitro studies were accomplished using the Bauhinia acuminate pollen cell to check the cell penetrability of the sensor molecule. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fluorometric and colorimetric detection of Hg2+ at nano-molar level. [•] Computational studies (DFT calculation) nicely support the experimental findings. [•] LOD was 1×10−9 M in HEPES buffer (0.1 M in EtOH/water, 1/1, v/v, pH 7.4). [•] Trace level Hg2+ can be detected in living cells under fluorescence microscope. [ABSTRACT FROM AUTHOR]

Abstract: A sensitive and selective new chemodosimeteric chemosensor (DIBT) for mercury ions was successfully devised and characterized. Upon addition of Hg2+ to DIBT, a red-edge absorption band at 972nm was observed. An important feature for the new chemodosimeter is its high selectivity toward mercury ions over the other competitive species due to Hg2+-triggered specific C–S cleavage, making the ‘naked-eye’ detection of mercury ions possible in aqueous solution and living cells such as Candida albicans. [Copyright &y& Elsevier]

Abstract: A new nonfluorescent benzthiazole derivative of dithio-N-phthaloylglycine was prepared, and its fluorogenic chemodosimetric behaviors toward transition metal ions were investigated. The dithio-N-phthaloylglycine derivative showed highly Hg2+-selective fluorescence enhancing (“turn-on”) properties in 20% aqueous acetonitrile solution (H2O/CH3CN=80:20, v/v). The chemodosimetric behavior is based on the Hg2+ triggered desulfurization of dithio-N-phthaloylglycine derivative into its oxygen analogue. To observe the cell permeability of 3 into Pollen grains, we also employed it for the fluorescence detection of the changes of intracellular Hg2+ in cultured cells. [Copyright &y& Elsevier]