Equilibrium Studies of 2,2'-(5-Bromo-6-Methylpyrimidine-2,4-Diyl)bis(azanediyl)dipropanoic Acid With Some Transition-Metal Ions in Aqueous Solution

Abstract

The stability constants of the 1:1 complexes formed between M 2+ (M 2+ : Mn 2+ , Ni 2+ , Cu 2+ , or Cd 2+ ) and BMADA 2− (BMADA: 2,2'-(5-bromo-6-methylpyrimidine-2,4 diyl)bis(azanediyl)dipropanoic acid) were determined by potentiometric pH titration in aqueous solution (I = 0.1 mol L −1 , NaNO 3 , 25 °C). The stability of the binary M-BMADA complexes is determined by the basicity of the carboxyl or amino groups. All the stability constants reported in this work exhibit the usual trend, and the order obtained was. The observed stability order for BMADA approximately follows the Irving-Williams sequence. In the M-BMADA complexes, the M ion is able to form a macrochelate via the pyrimidine group of BMADA.