New Azobenzene Dye Colorimetric and Ratiometric Chemosensors for Mercury(II) Ion

A new series of azobenzene dyes, which possessed colorimetric and ratiometric recognition to Hg(2+) based on the mechanism of internal charge transfer (ICT), was developed and characterized. The molecules involving azo and imino functional groups can coordinate with Hg(2+) to result in a large blue shift from 453 to 363 nm corresponding to a notable color change from orange to pale yellow in aqueous methanol solution (H(2)O/CH(3)OH=1/4, V/V), which can be applied to naked eye detection of Hg(2+). The sensitivity, selectivity and binding mode of the sensors to Hg(2+) were investigated by UV-Vis spectroscopy.