The β-hydroxyethyl radical as a model system for two-pathway electroreduction in the presence of proton donors

The mechanism of electrode reactions of the β-hydroxyethyl radical has been found experimentally to depend on pH, and a general kinetic scheme of organic radical electroreduction is suggested which includes two parallel pathways of electron transfer, either to adsorbed radical R_ads or to its metastable protonated complex [R_ads·BH⁺]; the competition between these pathways is determined by the capacity of R_ads for complex formation, the concentration of the proton donor, and electron transfer rates to R_ads and [R_ads·BH⁺].