Recyclable fluorescent chemodosimeters based on 8-hydroxyquinoline derivatives for highly sensitive and selective detection of mercury(II) in aqueous media and test strips

Development of a novel sensory material for rapid detection of mercury ions in various water sources: Solution and solid-state analysis

A xanthene propane nitrile-based sensor material was successfully prepared, and an attempt towards the preparation of polymer bead form was made for the sensitive or selective detection of mercury ions (Hg2+) in water. The sensor material in solution as well as in polymeric form showed amazing selectivity over other added metal ions with a naked eye color change, UV visible spectral and fluorescence spectral change, and a rapid and excellent color change from colorless to purple. The 1H NMR study exposed the probable binding site of the probe with the added mercury ion. In this study, the imine nitrogen and the C = O interact with the mercury ion, resulting in the ring opening of lactam with a vivid color change. The EDTA test was done to verify the reversible behavior of the probe and confirmed its reversibility by UV-visible and fluorescence spectral studies. The polymer bead made using this probe can be used as a tool for monitoring mercury ions in real time in different sources of water samples. The sensor molecule itself senses the mercury ion in its solid state by simple grinding and changes its color from pale yellow to deep purple. The sensor color change response is very rapid towards mercury detection, which is confirmed by the prepared test strip.

Tunable full-color emission of stilbazoles containing a 2-halo-3,4-dicyanopyridine acceptor

Synthesis of a series of novel push-pull stilbazole-based chromophores containing a strong 2-halocinchomeronic dinitrile acceptor is reported. The photophysical properties of the compounds are described. Strong positive solvatofluorochromism typical of intramolecular charge transfer (ICT) dyes is observed for the synthesized stilbazoles. Their tunable multicolor emission ranges from 442 nm to 710 nm and covers the whole visible spectrum.

Novel fluorescent probe based on dicoumarin for rapid on-site detection of Hg2+ in loess

It is momentous to exploit rapid, specific and on-site detection methods for mercury ion (Hg²⁺) in loess, as the severe toxicity of Hg²⁺ and the fragile ecological environment of Loess Plateau. In this paper, a novel fluorescent probe DC-Hg (Dicoumarin-Hg) was synthesized by 3-hydroxybiscoumarin and phenyl thiochloroformate at room temperature. DC-Hg could exclusively combine with Hg²⁺ to 'turn-on' yellow fluorescence at 530 nm among various other metal ions. The relationship between the remarkable increase in intensity and concentration of Hg²⁺ was associated with photoinduced electron transfer (PET), which was founded by Job's plot and ¹H NMR. The limit detection of DC-Hg showed to 85.25 nM in aqueous medium, which could be applied to varying situations. For the loess samples, they were only extracted by hand-shake and filtration for quickly complete the treatment operation on site, and the results proved that DC-Hg could satisfactorily detect the Hg²⁺ in mercury pollution areas.

An oxacalix[4]arene-derived dual-sensing fluorescent probe for the relay recognition of Hg2+ and S2− ions

A rhodamine B-functionalized oxacalix[4]arene architecture has been designed as a dual-responsive probe for the sequential recognition of Hg2+ and S2− ions.

8-Hydroxyquinoline Fluorophore for Sensing of Metal Ions and Anions

Among various known hydroxyquinolines, 8-hydroxyquinoline (8-HQ) is the most prevalent moiety due to excellent property for the formation of the complex with different metal ions and anions, and utilized in a wide variety of applications in pharmacological and medicinal fields. 8-Hydroxyquinoline moiety and its analogues acts as fluorophoric ligands on complex formation with alkali and alkaline as well as transition metal ions and anions, thus, considered as an ideal building block in metallo-supramolecular chemistry for recognition, separation, and quantitative investigation of cations. 8-Hydroxyquinoline moiety is also used in various applications for the advancement of novel fluorescent chemosensors in a wide variety of areas viz., material chemistry, bioorganic chemistry, molecular imaging, analytical chemistry, molecular recognition, medical and biological science communities. The present review emphasises on the progress of sensing properties of 8-HQ centred small-molecule fluorescent chemosensors towards several metal ions viz., Fe³⁺ , Al³⁺ , Ag⁺ , Hg²⁺ , Cu²⁺ , Pd²⁺ , Zn²⁺ , Cr³⁺ , Cd²⁺ , Mn²⁺ , Ca²⁺ , and K⁺ and anions such as F^- , CN^- and PPi, from 2008 to 2020, because of their sensitivity and selectivity in terms of diverse colour changes for different species. This critical and comprehensive review might facilitate the improvement of more prevailing chemosensors for future exciting and broad applications.

A quinoline-based probe for effective and selective sensing of aspartic acid in aqueous medium: in vitro and in vivo live cell imaging

A highly sensitive and selective “on–off–on” chemosensor for aspartic acid in aqueous solution was established. In vitro live cell imaging against MCF 7 cells and in vivo imaging using C. elegans were successfully demonstrated.