Voltammetry of organic ditellurides in protic media. Mercury assisted chemical pre-reactions with catalytic effects

The different reduction mechanisms of two types of organic ditellurides have been studied in aqueous/ethanolic media by voltammetry of interest for a mercury assisted chemical pre-reaction as a first step in the electrode process. Bis carboxymethyl ditelluride, HOOC-CH2-TeTe-CH2-COOH (I) and diphenyl ditelluride Ph-TeTe-Ph (II) were model compounds. During the reduction of (I) on the mercury electrode a strong catalytic evolution of free tellurium (Te-0) is observed indicating a Te-C bond cleavage. Contrary to this, the reduction of diphenyl ditelluride proceeds as a mercury assisted cleavage of the Te-Te bond. The reduction pattern for the aromatic ditelluride is compared with the corresponding aromatic selenium and sulphur analogues. Copyright (C) 1996 Elsevier Science Ltd.