Colorimetric Detection of Copper(II) Ions Using Schiff‐Base Derivatives

Two new Schiff base derivatives N,N‐dimethyl‐4‐((2‐(phenylthio) phenyl)imino)propenyl)aniline ( CSP ) and 2‐(4‐(dimethylamino)phenyl) allylidene) amino)benzenethiol ( CSH ) were synthesized. Sensing mechanism of the sensors was investigated using UV‐Vis spectroscopy in the presence of various metal ions. The sensor CSP shows high sensitivity and selectivity to Cu 2+ over a wide range of other metal ions in acetonitrile (ACN)/water (H 2 O) (v/v 2 : 1). The sensor CSP can detect Cu 2+ ions by color change from yellow to pink. The complex stoichiometry between the sensor, CSP , and Cu 2+ was found to be 2 : 1 and the binding constant was calculated to be 2.40 × 10 10  M −2 . The absorbance detection limit of CSP for Cu 2+ was determined as 2.85 × 10 −6  M. The sensor, CSP , was also applied to real samples successfully.