A new electrochemically formed, iodide-modified platinum electrode usable to -3 V versus SCE in dimethylformamide. Preliminary studies of the reduction of alkyl bromides and chlorides

A new kind of modified platinum electrode can be created if the electrode is cathodically polarized in dimethylformamide containing 0.10 M tetra-nbutylammonium tetrafluoroborate and small amounts of tetra-n-butylammonium iodide, if the medium has been previously dried in situ with activated alumina, and if the polarized electrode is subsequently exposed to oxygen for a few minutes. Cyclic voltammograms recorded with this modified electrode display a remarkably low residual current and exhibit a cathodic potential limit of -3 V versus SCE. Using such a modified electrode, we have observed well-defined cyclic voltammetric waves for the reductive cleavage of 1-bromopropane and 1-chlorooctane, two compounds that cannot be reduced at unmodified platinum cathodes.