Reactions of 1, 2-dithiolium cations and formation of metal thio-l-dicarbonyl compounds

The decomposition of three phenyl-substituted 1,2-dithiolium salts, 3,5-diphenyl-, 3-phenyl- and 4-phenyl- in aqueous, ethanol and DMSO solutions have been examined. With bases of the type hydroxide, ethoxide, DMSO, and acetate, the 1,2-dithiolium ion formed adducts reversibly. Orders of adduct stability were determined in ethanol and water. Many of the adducts were unstable and decomposed to monothio-(beta)-dicarbonyls. The monothio-(beta)-dicarbonyls were in turn unstable and decomposed in aqueous media to the corresponding-(beta)-diketone in the case of the monothiodibenzoylmethane.Reaction of the 1,2-dithiolium ions with sodium sulphide or sodium borohydride led to dithio-(beta)-dicarbonyls. These species were unstable and decomposed to monothio-(beta)-dicarbonyls in the presence of water. It was possible to observe the formation of metal chelates of monothio- and dithio-(beta)-dicarbonyls in DMSO for several systems. Metal ion and ligand stability orders were established.Chelates of dithio-(beta)-dicarbonyls decomposed to monothio-(beta)-dicarbonyls in the presence of trace amounts of water. Monothio-(beta)-dicarbonyl chelates were also sensitive to water with dibenzoylmethane produced from monothiodibenzoylmethane chelate decomposition.Mechanisms for 1,2-dithiolium ion decomposition in the presence and absence of metal ions have been proposed