Highly selective optical chemosensor for cyanide in aqueous medium

New cyanide selective chromogenic chemosensors based on metal-phthalocyanines containing four tosylamino groups were developed. These new receptors have high sensitivity for several anions (AcO−, F−, CN−, NO2−, H2PO4− and OH−) over other anions, such as: Br−, Cl−, NO3− and HSO4−. The experiments were conducted by UV–vis spectroscopy in DMSO and THF solutions. The selectivities were also checked in DMSO:water mixtures. In solutions containing water the highest selectivity was obtained for CN− anion. The host:guest complexes formed during the sensing event can be undo by acid treatment with a solution of trifluoroacetic acid without loss of the sensing ability of the chemosensors allowing their reuse.

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