Characterization of new sulfide ions (C2S3 .+) from ethenedithione by ion-molecule reactions

Abstract

Collisional activation (high or low translational energy) and neutralization-reionization mass spectrometries appear inefficient for the characterization of the connectivity of isomeric C2S3 .+ ions generated by dissociative ionization of 1,2-dithiolo[4,3-c][1,2]dithiole-3,6-dione (1), 1,2-dithiolo[4,3-c][1,2]dithiole-3-one-6-thione (2), and 1,3,4,6-tetrapentalene-2,5-dione (3). In contrast, ion-molecule reactions (particularly with nitric oxide) readily differentiate the C-sulfide ethenedithione ion, SCCS2 .+ (4), and the S-sulfide ethenedithione ion, SCCSS.+ (5). The collisional activation spectra of these ion-molecule reaction products have been recorded on a new type of hybrid tandem mass spectrometer of sectors-quadrupole-sectors configuration. The characterization of the isomeric C2S3 .+ ions is supported by ab initio calculations at the G2(MP2,SVP) level. The C-sulfide ethenedithione ion is predicted to be more stable than the S-sulfide form by 91 kJ mol-1. The calculated reaction enthalpies for the two isomeric forms C2S3 .+ with nitric oxide support the characterization by ion-molecule reactions.