Oxidative S-S-Kopplung von 1,2-Dithiooxalat durch intramolekulare Redoxreaktion der Selen(II)- und Tellur(II)-Komplexe/Oxidative S-S Coupling of 1,2-Dithiooxalate by Intramolecular Redox Reaction of the Selenium (II) and Tellurium(II) Complexes

Abstract

The reaction of sodium monochalcogenopentathionates, Na2[Y(S2O3)2] (Y = Se, Te) with potassiumdithiooxalate in a water/methanol solution in presence of large cations (e. g. Ph4P+, Ph4As+ or BzlPh3P+) yields complexes of the type [Y(dto)2]2- (Y = Se, Te). These complexes are of limited stability and undergo a redox reaction in solution. As the main product of this redox process the 3,4-dithiahexane-2,5-dione-1,6-di(thiocarboxylate) was isolated and characterized by X-ray structure analysis as the benzyltriphenylphosphonium salt (monoclinic space group P2J/c, Z = 2, a = 8.899(5) Å, b = 16.458(2) Å, c = 16.034(6) Å and β = 98.02(2)°). With Te2+ (Y = Te) as the coordination center we have been able to isolate the intermediate complex (Ph4P)2[Te(dto)2].