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 i s cathodically polarized in dimethylformamide containing 0.10 M tetra-n-but ylammonium tetrafluoroborate and small amounts of tetra-rt-butylammonium io dide, if the medium has been previously dried in situ with activated alumin a, and if the polarized electrode is subsequently exposed to oxygen for a f ew minutes. Cyclic voltammograms recorded with this modified electrode disp lay a remarkably low residual current and exhibit a cathodic potential limi t of -3 V versus SCE. Using such a modified electrode, we have observed wel l-defined cyclic voltammetric waves for the reductive cleavage of 1-bromopr opane and 1-chlorooctane, two compounds that cannot be reduced at unmodifie d platinum cathodes. (C) 2000 Elsevier Science S.A. All rights reserved.