In contrast, the Fc-COOH system exhibited a significant loss of electroactivity, which dropped by half within the first two hours and retained only 20% after 24 hours (Figure ). This rapid decline suggests the consumption of Fc-COOH in the dC12 mixture. A reasonable explanation is that the diazonium group is reduced by ferrocene in solution, producing aryl radicals that subsequently react with remaining ferrocene molecules. Such a reaction, described in the literature as the Gomberg-Bachmann coupling, involves aryl radicals attacking ferrocene groups and accounts for the observed loss of electroactivity . Additionally, a brown precipitate formed in the electrochemical cell during the study, likely arising from the radical-coupled product of this reaction.