Protolytic properties and complexation with copper(II) ions of some azo derivatives of β-arylaminopropionic acids
作者:E. V. Osintseva、L. K. Neudachina、Yu. G. Yatluk
DOI:10.1134/s0036023610100256
日期:2010.10
The azo coupling reaction of N-(2-carboxyethyl)anthranilic acid and N,N,N',N'-tetrabis(2-carboxyethyl)-1,3-phenylenediamine with diazosulfanilic acid yielded the complexones sodium 4-N-(2-carboxyethyl)amino-5-carboxyazobenzene-4'-sulfonate (I) and 2,4-N,N,N',N'-tetrabis(2-carboxyethyl)diaminoazobenzene-4'-sulfonic acid (II), respectively. The acidity constants of I and II (20A degrees C, mu = 0.1M KCl) were determined to be as follows: for I, pK (00) = 1.29 +/- 0.13, pK (0) = 2.92 +/- 0.07, pK (1) = 3.92 +/- 0.05, pK (2) = 5.16 +/- 0.03; for II, pK (00) = 2.35 +/- 0.06, pK (0) = 2.81 +/- 0.09, pK (1) = 3.21 +/- 0.11, pK (2) = 3.81 +/- 0.09, pK (3) = 4.34 +/- 0.04, pK (4) = 5.03 +/- 0.06, pK (5) = 6.67 +/- 0.07. The electronic absorption spectra of I and II were measured, and acid-base equilibrium scheme for I and II in aqueous solutions were suggested. The complexation constants of I and II with copper(II) ions were determined to be logK (CuQ) (I) = 5.47 +/- 0.06 and logK (CuQ) (II) = 5.72 +/- 0.13 (20A degrees C, mu = 0.1 M KCl).