3,6-Dihydro[1,2]dithiolo[4,3-c][1,2]dithiole-3,6-dithione and oxo analogues: a comparative study of the thermal (FVP) and electron ionization (EI) induced fragmentations

Abstract

Flash-vacuum pyrolysis (FVP) of the dithiolodithioledithione 2 in the 700–1000 °C temperature range affords carbon subsulfide, carbon disulfide and disulfur with high yields. This has been demonstrated by using a combination of FVP/IR (argon matrix) and FVP/MS(MS) experiments. SCCCCS is generated as ions by dissociative ionization of 2, not as neutrals upon pyrolysis. Similar behaviour is noted for the oxygen analogue 4: pyrolytic formation of carbon subsulfide, carbon oxysulfide and disulfur. It is also demonstrated that, upon dissociative ionization, dithiolodithioledione 3 and thioxodithiolodithiolone 4 constitute an interesting source of new cumulenic ions derived from carbon subsulfide and carbon oxysulfide, tentatively assigned as SCCCS+–S˙ and OCCCS+–S˙ radical cations by collisional activation (high and low energy) experiments and ion–molecule reactions with nitric oxide.