A colorimetric and fluorometric oligothiophene-indenedione-based sensor for rapid and highly sensitive detection of cyanide in real samples and bioimaging in living cells

A new simple oligothiophene-indenedione-based sensor 3TI has been synthesized for the highly reactive and selective detection of cyanide anion (CN-) in 70% aqueous media. The sensor 3TI displays distinct colorimetric and fluorometric detection of CN- due to the addition of CN- to the electron-deficient indenedione-vinyl group of 311, which hampers intramolecular charge transfer (ICT) efficiencies. The recognition mechanism of 3TI for CN(-)was confirmed by the optical measurements, H-1 NMR titration, FTIR spectra, HRMS analysis, and TD-DFT calculations. The sensor 3TI for CN-shows the outstanding advantages of high fluorescence brightness, fast response time (30 s), low detection limit (31.3 nM), minimal pH dependence in the physiologically relevant range, and excellent selectivity in presence of other competitive anions. Encouraged by these desirable sensing properties, the 3TI has been successfully used for determination of CN- in real water and food samples, silica based sensing kits and fluorescence imaging in living cells with satisfactory results.