A reversible fluorescent chemosensor for cyanide in 100% aqueous solution

A new fluorescent chemosensor, sodium 2-(2-(1H-benzo[d]imidazol-2-yl)quinolin-8-yloxy)acetate (HL), based on 8-hydroxyquinoline derivative has been designed, synthesized and characterized. Once combined with Hg2+ in aqueous solution, HL displays a fluorescence quenching effect to form the compound mercury(II) 2-(2-(1H-benzo[d]imidazol-2-yl)quinolin-8-yloxy)acetate chloride (LHg), which could be fast dissociated by the addition of cyanide in this system so that ON-OFF-ON type fluorescence change can be achieved. Cyanide induces the revival of fluorescence of LHg and results in OFF-ON type sensing with high sensitivity and rapid response in 100% aqueous system. Furthermore, the fluorescence microscopic imaging also indicates that LHg is suitable for the detection of CN- in biological environment. (C) 2013 Elsevier B.V. All rights reserved.