SSOH and HSSO radicals:: An experimental and theoretical study of [S2OH]0/+/- species

New radicals containing sulfur-sulfur bonds are detected in the gas phase: disulfur hydroxide SSOH and thiosulfenoxide HSSO, stable toward dissociation by ca. 50 and 40 kcal mol(-1), respectively. Energetic, structural features and fragmentation pathways of these [S2OH] radicals and their charged species [S2OH](+) and [S2OH](-) are experimentally and computationally investigated by mass spectrometric techniques and ab initio calculations. [S2OH](+) is obtained by various ion-molecule reactions leading to S2O protonated on the oxygen and end-sulfur atoms, whose proton affinity is computed at different levels of theory. The first detection of [S2OH](-), the conjugate base of the oxatrisulfane HSSOH, is also reported.