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Electrochemical and spectroelectrochemical study of copper bleomycin complexes
Author(s) -
Fultz Mary Lou,
Durst Richard A.
Publication year - 1991
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140030612
Subject(s) - chemistry , coulometry , copper , glassy carbon , polarography , electrochemistry , inorganic chemistry , redox , cyclic voltammetry , platinum , electrode , catalysis , organic chemistry
The electrochemical behavior of the copper(II) complex of bleomycin, a glycopeptide antibiotic with antitumor activity, was investigated in several buffer systems using cyclic voltammetry, polarography, coulometry, and spectroelectrochemistry. The copper bleomycin complex exhibited irreversible one‐electron reduction on glassy carbon and mercury electrodes and was electroinactive on platinum, gold, and silver. After the initial reduction process on mercury, the appearance of the Cu(0)/(II) redox couple indicated dissociation of the complex and subsequent reduction of the Cu(I) to the metal. In the presence of excess bleomycin, the Cu(II) reoxidized from the mercury electrode is rapidly complexed and no copper reduction process is observed. On glassy carbon, however, the Cu(I) bleomycin complex is stable and does not undergo further reduction, as demonstrated by spectroelectrochemistry at a reticulated vitreous carbon optically transparent electrode. Consequently, as with many metallo‐organic redox processes, there appear to be several possible electrochemical pathways depending on the pH, the electrode materials, and the experimental time domain.