ELECTROCHEMICAL-BEHAVIOR OF 1,2-DIHYDROXYCYCLOBUTEN-3,4-DIONE IN DIMETHYL FORMAMIDE

The electrochemical behaviour of 1,2-dihydroxycyclobuten-3,4-dione (sq uaric acid, H2SQ) in dimethylformamide was investigated. On a Pt elect rode, the reduction involves two successive, chemically reversible, on e-electron processes, affording hydrogen and the basic species HSQ- an d SQ2- respectively. The oxidation of SQ2- thus formed occurs in two c onsecutive, chemically reversible, one-electron steps, affording the r adical anion SQ.- and the neutral species SQ-degrees; the neutral spec ies SQ-degrees is stable in the time-scale of the voltammetric experim ents only. In contrast, the chemically irreversible oxidations of H2SQ and HSQ- appear as more complicated processes. The oxidation of hydro gen in the presence of the electrogenerated basic species was also stu died. A comparison with the results obtained on an Hg electrode is mad e and the occurrence of a different voltammetric behaviour, as regards the reduction process, is discussed briefly.