"Development of Anaerobic Catalyst for Indirect Electro-Oxidation Reactions of Alcohols using Copper Bipyridinimine Complexes"
In this study, we investigate the indirect electro-oxidation of benzyl alcohol utilizing the Copper/TEMPO catalytic system, which combines copper complexes with 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) in an anaerobic medium. Here, we meticulously reexamines the impact of bpy ligand proportions exploring ratios of 1:1, 2:1, 3:1, and 4:1 for the catalytic activity. The integration of cyclic voltammetry (CV) and visible spectroscopy reveals distinct electrochemical characteristics and complex formations at different bpy ratios. The Brønsted base, triethylamine (TEA), crucial in the Copper/TEMPO anaerobic system, exhibits different voltammetric profiles with each ligand ratio, revealing transformative evidence and interactions with bpy complexes. In the presence of benzyl alcohol, the 1:1 and 2:1 ratios exhibit indirect catalytic activity, with the 2:1 ratio displaying notably higher current densities. These findings establish a new optimal condition, where [(bpy)2Cu(II)] formed in the 2:1 stoichiometry demonstrates superior activity with a lower redox potential maintaining labile coordination points for necessary interactions.