A facile ratiometric and colorimetric azo-dye possessing chemosensor for Ni2+ and AcO- detection

A new tailor-made colorimetric chemosensor 1, containing pyridine and benzothiazole moieties connected through an azo (-N=N-) linkage has been synthesised. In 9:1 (v/v) aqueous THF (pH 7.0 HEPES buffer), it showed a conspicuous naked-eye colour change upon binding to Ni2+ (colourless to light green) and AcO- (colourless to orange) resulting in their ratiometric sensing. The cation and anion recognition property of the chemosensor 1 was monitored by UV-vis spectral analysis and H-1 NMR titrations.