Dicyanovinyl terthiophene as a reaction based colorimetric and ratiometric fluorescence probe for cyanide anions

3'-Dicyanovinyl terthiophene 3 was synthesized and the changes in absorption and emission properties of 3 in the presence of various anions were evaluated. Compound 3 acts as a selective colorimetric as well as a ratiometric fluorescence probe for cyanide anions in aqueous THF solution even in the presence of other anions such as AcO-, F-, Cl-, Br-, NO2-, N-3(-), HS- and ClO4-. Obstruction in an intramolecular charge transfer ( ICT) by the nucleophilic addition of a cyanide anion to the dicyanovinyl group induces remarkable changes in the absorption and emission spectra of 3. The signal transduction mechanism was investigated by absorption and emission spectroscopy, H-1 NMR titration and DFT calculations.