Dithiolate and diselenolate complexes [Pt2(μ-ECH2CHCHCH2E)(PPh3)4]2+ (E = S, Se): Synthesis, characterisation and mass spectrometric formation of the dichalcogenide species [Pt2(μ-E2)(PPh3)4]2+

Alkylation reactions of [Pt2(μ-E)2(PPh3)4] with cis-1,4-dichlorobut-2-ene (cis-ClCH2CHCHCH2Cl) gives the complexes [Pt2(μ-ECH2CHCHCH2E)(PPh3)4]2+, which undergo a facile fragmentation reaction in ESI mass spectrometry, via a retro-Diels-Alder reaction and loss of 1,3-butadiene, giving the dichalcogenide species [Pt2(μ-E2)(PPh3)4]2+.