A New Bioactive Thiazolidinone-based Azo Dye for Naked-eye Colorimetric Detection of Cyanide Ions

: A new bioactive azo dye embedding a thiazolidinone heterocyclic core was designed and synthesized for antibacterial application and colorimetric sensing of cyanide ion (CNˉ) in organic solutions. The structure of the prepared dye was elucidated from its 1H NMR, FT-IR and UV–vis spectral data. It proved to be a fast and sensitive colorogenic sensor for detection of CNˉ. Spectroscopic studies were carried out to investigate the effect of different CNˉ concentrations on the detection efficiency. Moreover, the studies revealed no significant competition or influence of other anions on sensitivity of CNˉ detection by the synthesized dye. A Job's plot indicated a 1:1 stoichiometry of the dye and CNˉ in their colorful complex. Further development of the method for naked-eye detection of CNˉ in low-concentration aqueous solutions was achieved by using the cellulose papers painted with the dye. The as-prepared testing paper allowed CNˉ sensing in concentrations as low as 2 μM. Evaluation of the dye for antibacterial activities using the well diffusion technique displayed that its inhibitory activity is at least as good as and in some cases superior to ampicillin against the bacterial strains employed in the zone assay. In response to CN¯, the dye changes color from yellow to reddish brown that accounts for its significant interactions with CNˉ and affords a naked-eye sensing method without resorting to any spectroscopic instrumentation. background: Cyanide ion is a serious pollutant of industrial wastewaters and is highly toxic for mammals. objective: A new bioactive azo dye embedding a thiazolidinone heterocyclic core was designed and synthesized for antibacterial application and colorimetric sensing of cyanide ions in organic solutions. method: The structures of prepared dyes were confirmed by 1H NMR, FTIR and UV–vis spectroscopies. It was found to be a fast and sensitive colorogenic sensor for detection of CN¯ ions. result: . In response to CN¯ ion, Spectroscopic studies were investigated of the interaction of synthesized dye with cyanide ion in competition with other anions and different concentrations of cyanide ion. The result of the Job's plot indicating that the stoichiometry binding ratios of synthesized dye and CN¯ is 1:1. Further development of the method for naked-eye detection of cyanide ion in low-concentration aquase solutions was achieved by using the cellulose papers painted with the dye. The as-prepared testing paper allowed CN¯ sensing in concentrations of 2 µM. Evaluation of the dye for antibacterial activities using the well diffusion technique displayed that its inhibitory activity is at least as good as and in some cases superior to ampicillin against the bacterial strains employed in the zone assay.