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A novel pyrrole fused coumarin based simple and practicable molecular probe has been synthesized under metal free green conditions which can recognize copper (II) in acetonitrile solvent. The synthesized probe displayed fluorescence quenching through selective binding with Cu 2+ over other competitive metal ions. Job’s plot, 1 H NMR titration and Mass spectral study revealed that the most abundant species formed when metal to ligand ratio was 1:1. The limit of detection (LOD) for Cu 2+ was found to be 11.3 nM or 2 ppb which is significantly lower than the maximum contaminant level (1.3 ppm of Cu), according to United State Environmental Protection Agency (USEPA). The fluorescent sensor was highly cell permeable and illustrated fluorescence ‘Turn-Off’ in presence of Cu 2+ ions in fluorescent imaging of human cervical cancer (HeLa) cell. [ABSTRACT FROM AUTHOR]

Based on Cu 2+ - promoted hydrolysis reaction a rhodamine B derivative L containing a napthalene moiety has been synthesized as a fluorescence turn-on chemodosimetric probe for Cu 2+ in EtOH:H 2 O (3:1, v/v, 10 mM HEPES Buffer, pH ≈ 7). The Cu 2+ promoted ring opening and hydrolysis reaction of L leads to formation of the 2:1 ligand metal intermediate complex which rapidly converts to rhodamine-B and bis-Cu 2+ complex of 1, 8 diaminonaphthalene. The proposed sensing mechanism has been supported by ESI–MS, 1 H NMR, 13 C NMR, IR analysis and DFT calculations. The dye L exhibits high selectivity toward Cu 2+ over other relevant metal ions and anions in the physiological pH range 5–8 with a low detection limit of 60 nM. Application in confocal cell imaging in HeLa cells is also demonstrated in the current work. Additionally, L has been shown to be non-toxic and biocompatible for mammalian cells. [ABSTRACT FROM AUTHOR]

A new rhodamine 6G derived chemosensor L has been synthesized that selectively detects the presence of Cu 2+ ion over a host of other biologically important and environmentally relevant metal ions in aqueous alcoholic medium under physiological pH (ethanol: water, 1:1, v/v, pH 7.2). The significant enhancement of fluorescence intensity of L is caused by Cu 2+ ion induced cleavage of spirolactum bond in the rhodamine moiety. This mechanism is well supported by the crystal structure of the L-Cu 2+ complex that depicts two ligand units are bonded to two Cu 2+ ions. Color of the solution changes from light orange to dark pink upon metal binding which allows naked eye detection ion as well. Confocal microscopic experiments validate that the dye is potentially useful for the selective detection of Cu 2+ ion in living cells. Therefore the dye is an excellent fluorogenic and chromogenic chemosensor for the Cu 2+ ion in aqueous ethanolic medium and the living cell as well. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new BODIPY derivative 1 behaves as an “on–off” fluorescent sensor of Cu2+. [•] Complex 1·Cu 2+ displays “off–on” fluorescent spectral response to biothiols and S2−. [•] 1·Cu 2+ complex can better recognize glutathione compared with cysteine and homocysteine. [•] 1 exhibits high sensitivity for Cu2+ under physiological conditions and in living cells. [•] 1 can locates in lysosome used as fluorescent dye in cell imaging. [ABSTRACT FROM AUTHOR]