Highly selective optical chemosensor for cyanide in aqueous medium

Abstract

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.