SPECTROPHOTOMETRIC STUDY OF NICKEL (II) COMPLEXES WITH 2- HYDROXYTHIOLPHENOL AND ITS DERIVATIVES IN THE PRESENCE OF HYDROPHOBIC AMINES

The complexation reactions of nickel (II) with 2-hydroxythiophenol and its derivatives (2,5- dihydroxythiophenol, 2-hydroxy-5-chlorothiophenol, 2-hydroxy-5-bromothiophenol, and 2-hydroxy-5- iodothiophenol) in the presence of hydrophobic amines were studied by spectrophotometric methods. Aniline and N, N-dimethylaniline were used as hydrophobic amines. It found that mixed-ligand complexes (MLC) are formed in a weakly acidic medium (pH 2.3-8.0). The maximum in the light absorption spectrum of the complexes is observed at λ = 620-650 nm. The molar coefficients of light absorption are (4.1-4.3)×104 . The best extractants were chloroform, dichloroethane and carbon tetrachloride. With a single extraction with chloroform, 97.8-98.4% of nickel is extracted in the form of MLC. Based on the data obtained, photometric methods for the determination of nickel in various objects were developed.