Investigation of Multidentate Ligand complexes with Some Late Transition Metal Ions

Abstract

Formation of the species MHA (M = Ni²⁺, Cu²⁺, Pd²⁺, Cd²⁺), MA,
MA(OH), M₂A (M = Cu²⁺ or Pd²⁺),  Pd₂A(OH),  MHB (M = Ni²⁺, Zn²⁺,
Pd²⁺, Ag⁺ or Cd²⁺) and MB (M = Ni²⁺, Zn²⁺, Pd²⁺ or Ag⁺ [where A =
pentaanion of 1-hydroxy-8-(2-hydroxy-naphthylazo )-2-(sulphonaphthylazo)-
3,6-disulphonic acid and B = tetraanion of 2-hydroxy-1-(2-hydroxy-
4-sulpho-1-naphthylazo )-3-naphthoic acid] has been inferred in aqueous
solution in pH-metric experimental measurements of the corresponding
metal-ligand mixtures. Equilibrium constants related to the complex
species present have been evaluated at 25°C (μ = 0.10 M KNO₃) and involvement
of the ligand donor groups in coordination, under different ratios
of the reactants and pH variations of the reaction mixtures, have been
discussed.