Nucleophilicity mediated interactions of ions with sensor: An anion induced BODIPY based chemodosimeter for sensing of CO2 gas

A BODIPY based chemodosimeter was designed and synthesized for detection of CO 2 gas in presence of F - /CN - ion. The changes were observed in the absorption spectra of the probe and corresponding colour changes were clearly distinguished by naked eye. The mechanism of sensing was studied by NMR titration which reveals that unlike previous reports our probe can detect as well as trap CO 2 through adduct formation. The sensing of CO 2 was also extended to solid state through immobilizing the probe into hydrogel matrix as well as onto silica. Both hydrogel composite and silica loaded with the probe exhibit colour changes upon exposure to CO 2 . Also, the practical application of the probe was demonstrated through detection and estimation of dissolved CO 2 in carbonated beverages. Moreover, the probe can detect F - and CN - through two different mechanisms governed by the nucleophilicity of the anion. The type of interaction of the probe with F - and CN - were elucidated with absorption and NMR study. Both the F - and CN - ions induced quenching of emission of the probe owing to activation of PET (Photo -induced Electron Transfer). The anion induced change in fluorescence intensity of the probe was also demonstrated with theoretical study. Moreover, the practical applicability of the probe for CN - sensing was established through sensing of CN - in 100% aqueous solution.