The electrochemical behaviour of [2H] benziso-1,2-selenazol-3-one (2b) in non aqueous media was studied using a platinum electrode. The corresponding Se-monoxide 3 was isolated and characterised. Comparison with [2H] benziso-1,2-thiazol-3-one (2a), [3H] benzo-1,2-dithiol-3-one (4a) and [3H] benzo-2,1-thioselenol-3-one (4b) was performed. In the case of compounds 2a,b the impact of the availability of the lone pair of the nitrogen atoms adjacent to the selenium atom on the electrochemical behaviour is discussed.

The electrochemical behaviour of [2H]benziso-1,2-thiazol-3-one in non-aqueous media has been studied using platinum electrode. A new indirect electrochemical synthesis of [2H]benziso-1,2-thiazol-3-one S-oxide mediated by chloride anion was performed in quantitative yield.

The electrochemical behaviour of 2-(benzylseleno)benzanilide was investigated by voltammetry using a rotating platinum electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. The measurements were made in acetonitrile medium. Comparison in terms of potential values and obtained products were made between 2-(benzylseleno)benzanilide, benzyl phenyl selenide and their sulphur analogues.

The electrochemical behaviour of benzyl phenyl selenide was investigated by voltammetry using a rotating platinum disk electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. The measurements were made in acetonitrile solution. In contrast to the case of benzyl phenyl sulfide, the oxidation products diphenyl diselenide, benzaldehyde and N-benzylacetamide result from the evolution of benzyl phenyl selenoxide and not from the corresponding initially formed radical cation

The electrochemical behaviour of 2-(methylseleno)benzanilide, one of the major metabolites of Ebselen, together with a series of 2-methylseleno-(4′-X-phenyl)benzamides were investigated by voltammetry using a rotating platinum electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. The measurements were realized in acetonitrile solution. The influence of temperature and acid on the nature of the oxidized products is shown. Comparison with their thio analogs is discussed.

The electrochemical oxidation of 2-phenyl-1.2-benzisothiazol-3(2H)-ones and related compounds in acetonitrile solution was studied by voltammetry using a rotating platinum electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. Further oxidation of studied compounds gave the corresponding sulfoxide. Comparison of the cyclic compound and related open-chain compounds was discussed.

The electrochemical oxidation of dibenzo(c,e)-1,2-diselenine 1b has been investigated in acetonitrile medium by voltammetry at rotating platinum electrode, cyclic voltammetry and constant potential coulometry. The exhaustive oxidation of compound 1b exclusively leads to the formation of the monoxide of dibenzo(b, d)selenophene with concomitant extrusion of selenium dioxide. The influence of the duration and the temperature of the electrolysis is reported. Each step of the electrochemical oxidation is described in detail. Comparison with the chemical and electrochemical oxidation of dibenzo)c, e)-1,2-dithiine and the chemical oxidation of cyclic vic-diselenide is discussed.

The electrochemical oxidation of benzo(b)selenophene and dibenzo(b,d)selenophene in non-aqueous media has been studied using platinum and glassy carbon electrodes. The selenoxide of dibenzo(b,d)selenophene has been isolated. A mechanism consistent with voltammetric measurements has been established. The electrochemical oxidation of dibenzo(b,d)thiophene was discussed and compared with its seleno analog.

The electrochemical properties of dibenzo(c,e)-1,2-dithiin in acetonitrile solution are investigated by voltammetry at rotating platinum and vitrous carbon disk electrodes, and by cyclic voltammetry and constant potential coulometry. Attention is particularly devoted to the first charge transfer step and the subsequent chemical reactions. Evidence for an ECE process is given. Comparison of the chemical and electrochemical oxidation of dibenzo(c,e)-1,2-dithiin and related open-chain compounds is discussed.

Abstract The electrochemical oxidation of dibenzo(c, e)-1,2-diselenine 1b has been investigated in acetonitrile medium by voltammetry at rotating platinum electrode, cyclic voltammetry and constant potential coulometry. The exhaustive oxidation of compound 1b exclusively leads to the formation of the monoxide of dibenzo(b, d)selenophene with concomitant extrusion of selenium dioxide. The influence of the duration and the temperature of the electrolysis is reported. Each step of the electrochemical oxidation is described in detail. Comparison with the chemical and electrochemical oxidation of dibenzo(c, e)-1,2- dithiine and the chemical oxidation of cyclic vic-diselenide is discussed.

The electrochemical oxidation of benzo(b)selenophene and dibenzo(b,d)selenophene in nonaqueous media has been studied using platinum and glassy carbon electrodes. The selenoxide of dibenzo(b,d)selenophene has been isolated. A mechanism consistent with voltammetric measurements. has been established. The electrochemical oxidation of dibenzo(b,d)thiophene was discussed and compared with its seleno analog.

The electrochemical behaviour of 7-substituted benzisoselenazol-3-(2H)-ones (BISAs) was investigated by voltammetry using a rotating platinum electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. The measurements were realized in “dry” neutral and acidic acetonitrile. Further oxidation od studied compounds gives the corresponding selenoxide. The role played by the protons during the reduction of this selenoxide has been demonstrated. The presence of a substituent in the 7-position of the benzisoselenazolin-3-one system strongly influence the values of the first oxidation potential. The nature of this interaction is discussed. A good correlation between thr first oxidation potential and the σortho Hammett coefficient is obtained. These results provide further evidence for the lack of association between the direct oxidation of BISAs into the corresponding selenoxide and the high (GSP-Px)-like activity of the 7-substituted BISAs.

The electrochemical properties of selenoxanthene, selenoxanthene-9-ol and selenoxanthone in non-aqueous and mixed media are investigated by voltammetry at rotating platinum and vitrous carbon disk electrodes, cyclic voltammetry, chronopotentiometry and constant potential coulometry. In “dry” acetonitrile selenoxanthene leads to selenoxanthylium cation. In the presence of water, selenoxanthene-9-ol is obtained. Further oxidation of selenoxanthene-9-ol gives the selenoxanthone which can be oxidized to the corresponding selenoxide. Influence of acids and bases is shown.

The electrochemical behaviour of twelve seleno-organic compounds structurally related to ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) has been investigated in acetonitrile medium on a platinum electrode. Influence of acids, bases and water on voltammograms are shown. A common primary oxidation step is identified and a selenoxide formation mechanism is suggested with the help of controlled-potential electrolysis and coulometry; this is fully corroborated by spectroscopic evidence. A good linear relationship is observed between peak potentials and the Hammett constant values of the substituents. Possible correlation between oxidation potential values and physiological activities of these seleno-organic compounds is suggested.

The electrochemical behaviour of twelve seleno-organic compounds structurally related to ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) has been investigated in acetonitrile medium on a platinum electrode. Influence of acids, bases and water on voltammograms are shown. A common primary oxidation step is identified and a selenoxide formation mechanism is suggested with the help of controlled-potential electrolysis and coulometry; this is fully corroborated by spectroscopic evidence. A good linear relationship is observed between peak potentials and the Hammett constant values of the substituents. Possible correlation between oxidation potential values and physiological activities of these seleno-organic compounds is suggested.