Dithiolate and diselenolate complexes [Pt2(μ-ECH2CHdouble bond; length as m-dashCHCH2E)(PPh3)4]2+ (E = S, Se): Synthesis, characterisation and mass spectrometric formation of the dichalcogenide species [Pt2(μ-E2)(PPh3)4]2+

The reactions of [Pt2(μ-E)2(PPh3)4] (E = S, Se) with cis-1,4-dichlorobut-2-ene (cis-ClCH2CHdouble bond; length as m-dashCHCH2Cl) give the dichalcogenolate complexes [Pt2(μ-ECH2CHdouble bond; length as m-dashCHCH2E)(PPh3)4]2+; an X-ray structure determination on the thiolate complex was carried out. The complexes give the expected dications in ESI mass spectra recorded at very low cone voltages, but at moderate cone voltages undergo facile fragmentation via a retro-Diels–Alder reaction and loss of 1,3-butadiene, giving the dichalcogenide species [Pt2(μ-E2)(PPh3)4]2+. Analogous species containing bidentate phosphine or arsine ligands have been previously generated electrochemically, and studied theoretically.