1, 5-Bis (2-hydroxyacetophenone)thiocarbohydrazone: a novel colorimetric and fluorescent dual-mode chemosensor for the recognition of fluoride.

1,5-Bis (2-hydroxyacetophenone)thiocarbohydrazone (H4L) has been synthesized and characterized by means of spectroscopic and single crystal X-ray diffraction methods. Interactions of the H4L with a variety of anions were investigated using a combination of UV-visible and fluorescence spectroscopic methods in a biological competing solvent DMSO. The H4L has a high degree of selectivity for fluoride over other anions. (1)H NMR titration experiments indicate that a deprotonation process is involved in the chemo sensing process.