Spectroelectrochemical study of the copper(II) transfer assisted by 6,7-dimethyl-2,3-di(2-pyridyl)quinoxaline at the water vertical bar 1,2-dichloroethane interface

L Tomaszewski, ZF Ding, DJ Fermin, HM Cacote, CM Pereira, F Silva, HH Girault*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

32 Citations (Scopus)

Abstract

The assisted transfer of Cu(II) by interfacial complexation with 6,7-dimethyl-2,3-di(2-pyridyl)quinoxaline (DMDPQ) is studied at the polarised water\1,2-dichloroethane junction. Thermodynamic and kinetic aspects were addressed by cyclic voltammetry and in situ spectrophotometric measurements. The dependence of the half wave transfer potential on the ligand concentration suggests that the equilibrium is effectively displaced towards a 1:3 (metal:ligand) stoichiometry, with an association constant of log beta(3)degrees = 26.0. Visible spectra recorded by reflection from the aqueous phase showed the presence of two absorption bands at 400 and 500 nm associated with the Cu(II) complex. Chronoabsorptometric studies in the presence of a ligand excess suggest that the assisted transfer kinetics are effectively controlled by the diffusion of the metal ion to the interface. (C) 1998 Elsevier Science S.A. All rights reserved.

Original languageEnglish
Pages (from-to)171-177
Number of pages7
JournalJournal of Electroanalytical Chemistry
Volume453
Issue number1-2
Publication statusPublished - 14 Aug 1998

Keywords

  • quinoxaline derivative
  • metal extraction
  • differential cyclic voltabsorptometry
  • chronoabsorptometry
  • IMMISCIBLE ELECTROLYTE-SOLUTIONS
  • FACILITATED ION TRANSFER
  • CURRENT-POTENTIAL CURVES
  • VOLTAMMETRY
  • WATER
  • COMPLEX

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