On the structures and fragmentation of [Me 2S∵SMe 2] + and [Et 2S∵SEt 2] +: Tandem mass spectrometry metastable and collision-induced dissociation results

An experimental study of the metastable and collision-induced dissociation (CID) spectra of [Me 2S∵SMe 2] + and [Et 2S∵SEt 2] + has been carried out. These ions are examples of species that contain two-center-three-electron (2c-3e) sulfur-sulfur bonds. The metastable and CID spectra provide experimental evidence of the atomic connectivity and of the 2c-3e bonds. The metastable cleavage of the S∵S 2c-3e bonds appears to occur with no reverse activation barriers and to result in small average kinetic energy releases. Fragmentation of the same bonds by CID results in the most intense product for both ions. Comparisons with the metastable and CID spectra of [MeSSMe] +, an ion with a two-center-two-electron (2c-2e) sulfur-sulfur bond, are made and strongly support the difference in the sulfur-sulfur bonding.