Cyanide Anion Determination Based on Nucleophilic Addition to 6-[(E)-(4-Nitrophenyl)diazenyl]-1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indole] Derivatives

This work provides a novel approach for the instant detection of CN− anions based on chromogenic 6-[(E)-(4-nitrophenyl)diazenyl]-1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indole] derivatives. New colorimetric detectors were synthesized and characterized. These compounds exhibited substantial color change from orange to magenta blue when treated with cyanide ions in CH3CN solution buffered sodium phosphate demonstrated high selectivity anions. Common tested, they did not interfere detection, except carbonates hydrosulfites. The simple preparation molecular sensor easily noticeable makes this practical system monitoring ions. is explained by nucleophilic substitution pyrane ring oxygen atom at indoline C-2 anion. generates appearance intensively colored 4-(4-nitrophenylazo)phenolate chromophore allows determining very low levels