Enolization versus carbonylation at glassy carbon surface through cathodic means

The cathodic reduction of ω-bromomethylarylketones in aprotic organic solvents (such as propylene carbonate) containing tetraalkylammonium iodides achieved at smooth glassy carbon (GC) permits through a selective one-electron reduction, the scission of the C-Br bond. Quite unexpectedly, the free radical thus formed is prior attached to the carbon surface in its enolic form (GC-O-(Ar)C=CH2). Successive radical addition processes may lead to a redox polymer based on the one-electron oxidation of enol ethers. The average superficial enol concentration at the carbon surface (found to be about 2.510 -8 mol cm -2 ) was assessed by the halogen index (iodine or bromine) via halogen addition to the double bonds followed by the micro-coulometric reduction of the resulting vicinal di-halo compounds. Key-words: ω-bromomethylarylketones; Glassy carbon; Enol radical grafting; Enolization; modified electrodes.