O-tert-butyldiphenylsilyl coumarin and dicoumarol: a case toward selective sensing of F- ions in organic and aqueous environments.

O-tert-Butyldiphenylsilyl coumarin 1 and 2 dicoumarol have been synthesized and their anion binding properties have been examined in organic and aqueous organic solvents. Compound 1 senses F(-) selectively over the other anions examined in CHCl3 by exhibiting a greater increase in emission. In contrast, compound 2 shows similar selectivity in CHCl3 giving ratiometric change in emission as well as color. In addition, both 1 and 2 are capable of detecting F(-) in water ensuing the cleavage of Si-O bonds. They also show cell permeability and demonstrate their abilities to detect F(-) in a living system.

Cholesterol appended pyridinium ureas: a case of gel making and breaking for selective visual readout of F-.

Cholesterol appended pyridinium ureas 1 and 2 have been designed and synthesized. The unsymmetrical urea-based chemosensor 1 fluorimetrically distinguishes F(-) from the other anions examined in both CH(3)CN and DMSO with appreciable binding constant values. The pyridinium - based symmetrical compound 2 acts as a low molecular weight gelator (LMWG) in CHCl(3) and is capable of detecting F(-) visually by breaking the gel. On the contrary, the chemosensor 1 in DMSO in the presence of tetrabutylammonium fluoride undergoes a change from sol to gel state that produces an unambiguous visual readout of F(-).

Fluorometric recognition of both dihydrogen phosphate and iodide by a new flexible anthracene linked benzimidazolium-based receptor.

A new flexible anthracene linked benzimidazolium-based receptor 1 has been designed, synthesized and its binding properties have been studied by NMR, UV-vis and fluorescence spectroscopic techniques. While the receptor 1 exhibits a greater change in emission in the presence of tetrabutylammonium dihydrogenphosphate in CH(3)CN over the other anions studied, iodide is selectively preferred in CHCl(3) containing 0.1% CH(3)CN. Upon complexation of dihydrogen phosphate and iodide, the emission of 1 gradually decreased without showing any other characteristic change in the spectra. Hydrogen bonding and charge-charge interactions interplay simultaneously in a cooperative manner for selectivity in the binding process.