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 language | English |
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Pages (from-to) | 141-146 |
Number of pages | 6 |
Journal | Journal of Solid State Electrochemistry |
Volume | 7 |
Issue number | 3 |
DOIs | |
Publication status | Published - Mar 2003 |
Keywords
- Copper
- Electro-insertion
- Macrocyclic ligand
- Metal extraction
- Voltammetry
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Electrochemistry
- Electrical and Electronic Engineering