Reactivity of [Pt2(μ-S)2(PPh3)4] towards activated aliphatic bromoacyl electrophiles: Formation of mono-, homodi-, heterodi- and intramolecular-bridged alkylated products

•Real time visualization of the reactions of [Pt2(μ-S)2(PPh3)4] with electrophiles.•Application of kinetic analysis in the dialkylation reactions of [Pt2(μ-S)2(PPh3)4].•Synthesis of μ-thiolate dicationic complex, [Pt2{μ-SCH2C(O)CH2CH3}2(PPh3)4]2+.•Isolation of dicationic complex, [Pt2{μ-SCH2C(O)C(CH3)3}{μ-SCH2C(O)CH2CH3}(PPh3)4]2+.•Preparation of novel bridged diplatinum complex, [Pt2{μ-SCH2C(O)C(O)CH2S}(PPh3)4]2+.

Reactions of [Pt2(μ-S)2(PPh3)4] with activated aliphatic bromoacyl alkylating agents BrCH2C(O)C(CH3)3, BrCH2C(O)CH2CH3 and BrCH2C(O)C(O)CH2Br, were investigated by electrospray ionization mass spectrometry (ESI-MS) in real time using pressurized sample infusion (PSI). The laboratory scale reactions gave the mono-, dicationic and bridged, μ-thiolate complexes [Pt2(μ-S){μ-SCH2C(O)C(CH3)3}(PPh3)4]+, [Pt2{μ-SCH2C(O)CH2CH3}2(PPh3)4]2+ and [Pt2{μ-SCH2C(O)C(O)CH2S}(PPh3)4]2+. Sequential reactions of [Pt2(μ-S)2(PPh3)4] with BrCH2C(O)C(CH3)3 and BrCH2C(O)CH2CH3 yielded the heterodialkylated complex [Pt2{μ-SCH2C(O)C(CH3)3}{μ-SCH2C(O)CH2CH3}(PPh3)4]2+. The products were isolated as the [BPh4]− or [PF6]− salts and characterized by ESI-MS, IR, 1H and 31P NMR spectroscopy and single-crystal X-ray crystallography.

Graphical abstractStable novel mono-, dicationic μ-thiolate complexes of [Pt2(μ-S)2(PPh3)4], [Pt2(μ-S){μ-SCH2C(O)C(CH3)3}(PPh3)4]+, [Pt2{μ-SCH2C(O)CH2CH3}2(PPh3)4]2+, [Pt2{μ-SCH2C(O)C(CH3)3} {μ-SCH2C(O)CH2CH3}(PPh3)4]2+ and [Pt2{μ-SCH2C(O)C(O)CH2S}(PPh3)4]2+, were obtained with activated aliphatic bromoacyl alkylating agents BrCH2C(O)C(CH3)3, BrCH2C(O)CH2CH3 and BrCH2C(O)C(O)CH2Br, through electrospray ionization mass spectrometry in real time using pressurized sample infusion. Figure optionsDownload full-size imageDownload as PowerPoint slide