Catalytic reduction of 1-bromooctane by nickel(I) salen electrogenerated at a mercury cathode in dimethylformamide

Cyclic voltammetry, controlled-potential electrolysis, and double-potential-step chronocoulometry have been used to characterize the catalytic reduction of 1-bromooctane by nickel(I) salen electrogenerated at a mercury cathode in dimethylformamide containing tetramethylammonium tetrafluoroborate. At a hanging mercury drop electrode, nickel(II) salen undergoes a reversible one-electron reduction. In the presence of excess 1-bromooctane, the peak current for reduction of nickel(II) salen is enhanced, whereas no current for oxidation of nickel(I) salen is observed. Controlled-potential electrolyses of solutions containing nickel(II) salen and 1-bromooctane lead to the production of n-octane, 1-octene, n-hexadecane, and di-n-octylmercury. Mechanistically, the formation of the various products involves the intermediacy of n-octyl radicals.