Complex Formation of Nickel(II) and Copper(II) with Barbituric Acid

Figure 2

Potentiometric pH profiles for solutions containing (I) BA, 𝑇_BA=2.0×10⁻³ M and Cu(II) and BA in the ratios, (II) 1 : 1 (𝑇_Cu=2.0×10⁻³ M and 𝑇_BA=2.0×10⁻³ M), (III) 1 : 2 (𝑇_Cu=2.0×10⁻³ M and 𝑇_BA=4.0×10⁻³ M), and (IV) 1 : 3 (𝑇_Cu=2.0×10⁻³ M and 𝑇_BA=6.0×10⁻³ M), respectively, 𝑇=25.0±0.1°C and 𝐼=0.1 MKNO₃.