The reactions of triethylamine-activated octasulfur with thioarsinites,L 2 As–SPh (L = Me,Ph),Bunsen’s cacodyl disulfide,Me 2 As(S)–S–AsMe 2,and triphenylarsine

Abstract

The reactions of L₂As–SPh (L = Me or Ph) with varying amounts of octasulfur, activated by triethylamine, aiming at the preparation of L₂As–S–AsL₂ and L₂As(S)–S–AsL₂ were slow and very complex in the sense that the composition in solution changed on work up. Generally, the disulfide L₂As(S)–S–AsL₂ was formed admixed with L₂As–S–NEt₃⁺ and L₂As–S⁻. The disulfide Ph₂As(S)–S–AsPh₂ was not stable during chromatography giving sulfur (S₈) and Ph₂As–S–AsPh₂ which was autoxidized to Ph₂AsO₂H·Ph₂As(S)OH. Bunsen’s cacodyl disulfide, Me₂As(S)–S–AsMe₂, was electrophilic toward activated octasulfur reacting at As = S sulfur. Triphenylarsine was oxidized to pure triphenylarsine sulfide in boiling ethanol by octasulfur in the presence of a catalytic amount of triethylamine in short time and with excellent yields.