Component complexation study of Ni(II) with 1,3-diphenyl-2-(2-hydroxy-4-nitrophenylhydrozo) propodion-1,3

The effect of various components, including α,α′-dipyridyl (α,α′-dip), phenanthroline (Phen) and bathophenanthroline (B-phen), on the complexation of Ni(II) with 1,3-diphenyl–2-(2-hydroxy-4-nitrophenylhydrozo)propodion-1,3 (R) was studied. Homogeneous (Ni(II)-R) and mixed-ligand (Ni(II)-R-α,α'- dip, Ni(II)-R-Phen and Ni(II)-R-B-phen) complex compounds are determined to form at pH = 6, 5.5 and 5, respectively. The yield of the Ni(II)-R complex is established to be maximal at R concentration of 8·10-5 M; Ni(II)-R-α,α'-dip – at concentration R and α,α'-dip of 8·10-5 and 5.2·10-5 M, respectively; Ni(II)-R-Phen – at concentration R and Phen of 8·10-5 and 4.8·10-5 M, respectively; Ni(II)-R-B-phen – at concentration of R and B-phen 8·10-5 and 4·10-5 M, respectively. All complexes, which differ in stability, were determined to form immediately after mixing the solutions of the components. The ratio of reacting components in the composition of homogeneous (1:2) and mixed (1:2:1) ligand compounds is established in terms of conformity to Beer's law. The equation coefficients for the calibration curve were obtained by the method of least squares. In the complexation of nickel(II), the А = f(c) dependence was shown to be expressed by linear equations. The stability constants of homogeneous (Ni(II)-R) and mixed-ligand (Ni(II)-R-α,α'-dip, Ni(II)-R-Phen and Ni(II)-R-B-phen) complexes were calculated. Under optimal complexation conditions, Ni(II)-R was titrated with a solution of the components, including α,α'-dip, Phen and B-phen, using the conductometric method. The effect of foreign ions on the complexation of nickel(II) with R both in the absence and presence of other components was studied. In the presence of other components, the selectivity of complexation reactions was established to increase significantly. These reagents were proved to be more selective for spectrophotometric determination of nickel(II) in comparison with reagents known from the literature. The developed technique was applied for nickel(II) determination in three varieties of apples.

α, nickel(II), azo-compounds, mixed-ligand complex, α, α'-dipyridyl, phenanthroline, bathophenanthroline