Electrochemical studies of some dithiadiazolylium cations; evidence for the dithiadiazolide anion, [PhCNSSN]?
| Autor: | Zdenek V. Hauptman, Michael I. Hansford, Anthony W. Luke, Christine M. Aherne, Arthur J. Banister, Jeremy M. Rawson, Ian B. Gorrell |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of the Chemical Society, Dalton Transactions. :967 |
| ISSN: | 1364-5447 0300-9246 |
| DOI: | 10.1039/dt9930000967 |
| Popis: | A series of para-substituted aryldithiadiazolylium salts [p-XC6H4[graphic omitted]][Y](X = H, Me, CF3, MeO, MeS, NO2, F, Cl, Br, CN or [graphic omitted]+; Y = Cl or AsF6) and [p-XC6H4[graphic omitted]][AsF6](X = H, Me, CF3, MeO, MeS, NO2, F, Cl, Br or [graphic omitted]+) has been prepared. An electrochemical study of both 1,2,3,5- and 1,3,2,4-dithiadiazolylium derivatives, as the hexafluoroarsenate(V) salts, showed reversible redox behaviour, forming the corresponding dithiadiazolyl radicals. The half-wave reduction potentials, E½(red), for the two isomeric dithiadiazolylium cations showed linear free-energy relationships between E½(red) and the Hammett value, σp, for the substituent group X; the σp values for [graphic omitted]+ and [graphic omitted]+ rings have been calculated at +0.537 ± 0.005 and +0.57 ± 0.02 respectively. A second reduction process was also observed for both 1,2,3,5- and 1,3,2,4-dithiadiazolylium cations, indicative of the formation of the dithiadiazolide anion, [p-XC6H4[graphic omitted]]–; a preparative-scale reduction of (Ph[graphic omitted])2 using sodium amalgam and 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) provided a yellow air-sensitive solid, [Na(18-crown-6)][Ph[graphic omitted]]. |
| Databáze: | OpenAIRE |
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