Chelating Tendencies of some N-(2-Methyl 4-Substitutedphenylazo )Phenylglycine Dyes
| Main Authors: | MADHUP CHANDRA, J. K. MEHROTRA, ARUN K. DEY |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 1974
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/6416495 |
Daftar Isi:
- Chemical Laboratories, University of Allahabad, Allahabad 211002 The step formation constants of chelates of six N-(2-methyl 4-substitutedphenylazo)phenyiglycine dyes with copper(II) and nickel(II) ions have been determined at 25, and at an ionic strength of 0.1M (NaClO4) in 50% aqueous dioxan (v/v) medium, employing pH-titration technique as adopted by Irving and Rossotti. Logarithms of the values of overall conditional formation constants of the dyes, viz. o-CIG, m-ClG, p-OCH3G, 3-.CI,pCH3G and 5-Cl o-CH3G for various complexation equilibria were found to be : protonation 5.54, 4.54, 5.24, 5.25, 5.36 and 5.17 ; copper chelates 7.27, 6.63, 7.18, 7.04, 7.55 and 6.87 ; and for nickel chelates 6.30, 6.23, 6.29, 6.23, 6.77 and 6.36 respectively. The effects of various substitutions on the dye molecule upon the stability of their metal chelates have been discussed on the basis of steric hindrance affecting the chelating tendency of the amino acid i.e. glycine of the dye molecule.