A new carbazole-benzothiazole based chemodosimeter for chromogenic and fluorogenic detection of CN–

Abstract

A hybrid carbazole-benzothiazole based chemodosimeter (CB) has been synthesized for the colorimetric and fluorogenic detection of cyanide ion (CN–). Intra-molecular charge transfer (ICT) played important role for the detection of CN– in DMSO-water (4/1, v/v, pH=7.2) solution. Upon treatment of CN– to the probe solution, results bleaching of the original yellow color of the probe with a large blue shift in absorption spectra. A large enhancement of the fluorescence intensity with a slight red shift is observed after addition of CN– to the probe (CB). Here, the nucleophilic addition of CN– inhibits the intra-molecular charge transfers (ICT) process responsible for the large enhancement of emission. The chemical reaction involved behind the sensing of CN– has been confirmed through 1H NMR and mass spectroscopic studies. The density function theory (DFT) and time-dependent density function theory (TDDFT) has also been conducted to support the experimental findings.