Abstrait

STUDY ON INTERACTIONS OF DIVALENT METAL IONS WITH ASPARTIC ACID IN BINARY COMPLEXES

S. A. A. SAJADI

The acidity constants of aspartic acid (ASP) were determined by potentiometric pH titration. The stability constants of the 1 : 1 complexes formed between M2+: Mn2+, Co2+, Cu2+ or Zn2+ and Asp2-, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that the stability of the binary M (Asp) complexes is determined solely by the basicity of the carboxylate or amin groups. The observed stability order for aspartate follows the Irving-Williams sequence. It is shown that Asp can exert a direct influence on reaction rate through both the kind of metal ions and the kind of donor groups of Asp.