Abstract

The electrochemical characteristics of polynuclear di-copper and tetra-copper complexes of an expanded "Robson-type" macrocyclic ligand are explored by solid state voltammetry in aqueous media. When adhered to a graphite electrode surface in the form of microcrystalline powders and immersed in aqueous buffer solution, these water-insoluble polynuclear copper complexes show well-defined voltammetric reduction and re-oxidation responses. The di-copper metal complexes [Cu2(H3L)(OH)][BF4]2 and the tetra-copper complexes [Cu4(L)(OH)][NO3]3 with an O4N4 octadentate macrocyclic ligand L are shown to exhibit inter-related and proton concentration sensitive solid state voltammetric characteristics. At sufficiently negative potential, copper is extracted from the complexes to form a solid copper deposit and the neutral form of the insoluble free ligand. Upon re-oxidation of the copper deposit, Cu2+ undergoes facile re-insertion into the ligand sphere to re-form solid di- and tetra-copper complexes at the electrode surface. The reduction process occurs in two stages, with two Cu2+ cations being extracted in each step. The ability of the macrocyclic ligand to efficiently release and accumulate copper is demonstrated.

Original languageEnglish
Pages (from-to)141-146
Number of pages6
JournalJournal of Solid State Electrochemistry
Volume7
Issue number3
DOIs
Publication statusPublished - Mar 2003

Keywords

  • Copper
  • Electro-insertion
  • Macrocyclic ligand
  • Metal extraction
  • Voltammetry

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Electrochemistry
  • Electrical and Electronic Engineering

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