Table 1: Stability constants and other related constants of binary, ternary and quaternary complex of α-ε-diaminocaproate (valine = A) and 5-methyl-2,4-dioxopyrimidine (uracil = B) with different metal ions in an aqueous solution at 37 ± 1 °C, I = 0.1 M NaNO3.
  (A) Proton-ligand formation constants (log β00rst)
Valine H2L −11.75
HL −9.95
Uracil HL −9.47
  (B) Hydrolytic constants (log βp000t/log β0q00t)
Cu Ni Zn Co
M(OH)+ −6.29 −8.10 −7.89 −8.23
M(OH)2 −13.10 −16.87 −14.92 −17.83
  (C) Metal-ligand constants (log βp0r00/log β0qr00/log βp00s0/log β0q0s0): Binary systems
Cu Ni Zn Co
ML1 8.11 5.42 4.86 4.45
ML2 8.25 6.81 6.63 6.27
  (D) Metal-ligand constants (log βp0rs0/log β0qrs0): Ternary systems
Cu Ni Zn Co
ML1L2 15.87 13.01 11.93 11.35
  (E) Metal-ligand constants (log βpqrs0): Quaternary systems
Zn−Co Cu−Ni Cu−Zn Cu−Co Ni−Zn Ni−Co
M1M2L1L2 23 22.01 21.87 20.96 18.46 19.32