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A novel colorimetric and fluorometric probe L1 for detecting CN− with high selectivity was constructed and synthesized based on intramolecular charge transfer (ICT). Remarkably, L1 was found to be exclusively responsive to CN− via nucleophilic attack of dicyanovinyl group via 1H NMR titration experiment. The detection system exhibited "turn-on" fluorescence with the addition of cyanide, which was opposite to previously reported fluorescence quenching probes with the same sensing process. Moreover, the detection limit of L1 for CN− was determined to be 1.1 μM, lower than the standard (1.9 μM) regulated by the World Health Organization (WHO). This work demonstrated that L1 could serve as both a colorimetric and a fluorimetric sensor for cyanide detection in pure water, making it possible for the applications of cyanide detection in water. Image 1 • A novel fluorescence "turn-on" probe for detecting cyanide was constructed based on intramolecular charge transfer.. • The probe can act as a colorimetric and a fluorimetric sensor in nearly pure water with the assistance of CTAB. • The probe possessed high selectivity for the detection of cyanide. [ABSTRACT FROM AUTHOR]

Abstract A simple novel dihydrophenazine-based chemosensor R has been developed for the detection of SO 3 2− in DMSO-H 2 O solution with turn-on fluorescence. Upon the addition of sulfite, the ICT (intramolecular charge transfer) system of the probe was destroyed owing to the nucleophilic addition of sulfite to the formyl group of R. Thus a charming orange-red fluorescence centered at 603 nm appeared, which is favorable for potential biosensing. The reaction mechanism was confirmed by MS and 1H NMR titration. In addition, the detection limit for sulfite was determined as low as 71.4 nM, which is superior to many reported probes. All above results promote the probe as a promising candidate in practical and biological applications. Graphical abstract Image 1 Highlights • A simple novel dihydrophenazine-based chemosensor R has been synthesized for the detection of SO 3 2−. • The probe has a charming turn-on orange-red fluorescence centered at 603 nm. • The detection limit for sulfite was determined as low as 71.4 nM. [ABSTRACT FROM AUTHOR]