A novel colorimetric and fluorescent probe based on a core-extended perylene tetra-(alkoxycarbonyl) derivative for the selective sensing of fluoride ions

A V-shaped bis-coumarin based fluorescence probe for F- detection in tea infusions and potable water and bioimaging applications in living systems

Fluorine (F) is a pivotal element in the formation of human dental and skeletal tissues, and the consumption of water and tea constitutes a significant source of fluoride intake. However, prolonged ingestion of water and tea with excessive fluoride content can lead to fluorosis, which poses a serious health hazard. In this manuscript, a novel turn-on fluorescent probe DCF synthesized by bis-coumarin and tert-butyldiphenylsilane (TBDPS) was introduced for detecting F- in potable water and tea infusions. By leveraging the unique chemical affinity between fluoride and silicon, F- triggers the silicon-oxygen bond cleavage in DCF, culminating in a conspicuous emission of yellow fluorescence. Validated through a succession of optical tests, this probe exhibits remarkable advantages in terms of superior selectivity, a low detection limit, a large Stokes shift, and robust interference resistance when detecting inorganic fluoride. Moreover, it can serve as portable test strips for on-site real-time identification and quantitative analysis of F-. Furthermore, the application of DCF for in-situ monitoring and imaging of F- in zebrafish and soybean root tissues proved its significant value for F- detection in both animal and plant systems. This probe potentially functions as an efficient instrument for delving into the toxic mechanisms of fluoride in physiological processes.

Sequence-Specific Relay Recognition of Multiple Anions: An Interplay between Proton Donors and Acceptors

Ratiometric detection of analyte is highly deserving since the technique is free from background correction. This work reports the design and synthesis of a pyridine-end oligo p-phenylenevinylene (OPV) derivative, 1 and its application in ratiometric dual-mode (both colorimetric and fluorogenic) recognition of dual anions, bisulfate (LOD=12.5 ppb) followed by fluoride (LOD=18.2 ppb) by sequence-specific relay (SPR) technique. The colorless probe turns brown with addition of bisulfate and again becomes colorless with the sequential addition of fluoride ion. In addition to such naked-eye color change, interestingly the ratiometric spectroscopic signals are reversible and evidently, the probe is reusable for several cycles. Besides, in presence of bisulfate, the protonated probe molecules, owing to their larger amphiphilic characteristics, formed self-assembled nanostructures. In addition to colorimetric and fluorescent changes, 1 H NMR titration and systematic DFT study evidently establish the underneath proton transfer mechanisms. Such reusable OPV-based chemosensor particularly with the capability of naked-eye recognition of dual anions using the SPR technique is seminal and possibly the first report in the literature.

Development of a fluoride-anion sensor based on aggregation of a dye-modified polyhedral oligomeric silsesquioxane

We report a new concept for a turn-on fluoride sensor based on the aggregation and release of a dye-modified polyhedral oligomeric silsesquioxane.