An electrochemical study on interaction of copper ions with three isomers, picolinic, nicotinic and isonicotinic acids at physiological pH

Biçer E., Tatlidil D.

RUSSIAN JOURNAL OF ELECTROCHEMISTRY, vol.52, no.1, pp.17-26, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 52 Issue: 1
  • Publication Date: 2016
  • Doi Number: 10.1134/s102319351601002x
  • Journal Name: RUSSIAN JOURNAL OF ELECTROCHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.17-26
  • Keywords: pyridine monocarboxylic acids, copper, complex, polarography and voltammetry, HALF-WAVE POTENTIALS, SPECTRAL PROPERTIES, CRYSTAL-STRUCTURES, STABILITY-CONSTANTS, AQUEOUS-SOLUTIONS, LIGAND COMPLEXES, METAL, CU(II), VOLTAMMETRY, REDUCTION
  • Ondokuz Mayıs University Affiliated: Yes

Abstract

The electrochemical behaviors of copper ions complexed with picolinic, nicotinic and isonicotinic acids (2-, 3- and 4-pyridinecarboxylic acids) in Britton-Robinson buffer (pH 7.4) was studied by polarographic and voltammetric techniques on a mercury electrode. This study showed that the reduction of complexed copper ions in the presence of nicotinic acid (NA) was carried out in two one-electron steps [Cu(II)/Cu(I) and Cu(I)/Cu(0)] whereas this cathodic process in the presence of picolinic acid (PA) or isonicotinic acid (INA) occurred in one two-electron step [Cu(II)/Cu(0)]. The stability of the Cu(I) complex can be sourced from the positions of carboxylate substituents on these isomeric ligands, binding to the copper center.