A novel colorimetric and fluorometric probe for the detection of CN- with high selectivity in aqueous media

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 H-1 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 mu M, lower than the standard (1.9 mu M) 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.