Determination of chromium (III) ions in water samples by UV–vis spectrometry based on benzyl-functionalized benzimidazolylidene ligand

Chromium is one of the most notorious environmental pollutants. The development of a sensitive and selective chromium detection method is an important issue. In this paper, cation recognition properties of two benzyl-functionalized benzimidazolylidene ligands towards metal ions were investigated by UV–vis spectrophotometry. The results showed that the receptors had a higher selection of Cr 3+ . The important analytical parameters, such as pH, quantity of the reagents, and their effects on the studied system were investigated. Under the optimum conditions the absorbance of the Cr 3+ -L complex obeys Beer9s law in the Cr 3+ concentration range of 0.05–2.60 μg/mL with the limit of detection of 0.026 and 0.034 μg/mL for L1 and L2, respectively. IR spectrum and DFT calculations were used to explore the coordinating sites and the complex strength of two ligands towards Cr 3+ . The thermodynamic parameters showed that complex formation is a spontaneous exothermic process. The proposed method was successfully applied to the determination of Cr 3+ content in water and alloy samples. The proposed method is seen as a simple and effective way of determining Cr 3+ concentration.