Simple and sensitive colorimetric sensors for the selective detection of Cu2+ in aqueous buffer

Simple chromogenic sensor for the selective detection of Cu2+ was described. With the addition of Cu2+, a bathochromic shift about 82 nm was observed in the UV–VIS spectra, with the color change from colorless to bright yellow. This suggested that the coordination between receptor and Cu2+ was formed, and the strong push–pull system occurred. The followed IR spectra indicated that Cu2+ coordinated to the two phenolic oxygen atoms and one of two azomethines in the receptor.