Potentiometric studies on the stability constants of some alpha-amino acid-copper(II) and nickel(II) systems in ethanol-water mixture


Dogan A. , Kilic E.

INDIAN JOURNAL OF CHEMISTRY SECTION A-INORGANIC BIO-INORGANIC PHYSICAL THEORETICAL & ANALYTICAL CHEMISTRY, vol.42, no.7, pp.1632-1635, 2003 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 42 Issue: 7
  • Publication Date: 2003
  • Title of Journal : INDIAN JOURNAL OF CHEMISTRY SECTION A-INORGANIC BIO-INORGANIC PHYSICAL THEORETICAL & ANALYTICAL CHEMISTRY
  • Page Numbers: pp.1632-1635

Abstract

The stability constants for the nickel(H) and copper(H)-alpha-amino acid (glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-serine, L-phenylalanine and L-methionine) binary complex systems have been studied using pH-measurements in 40% ethanol-60% water mixture. The study shows that at 25degreesC and ionic strength at 0.10 M the following species are present in this solvent mixture: CuHL2+, CuL+, CuL2 for copper(II) complexes and NiL+, NiL2, NiL3- for nickel(II) complexes. The stability of the nickel(H) complexes is lower than that of the copper(II) complexes. The study shows that the tendency of alpha-amino acids to form complexes with metal(II) ions is greater in 40% ethanol-60% water mixture as compared to that in only water.