Stable diplatinum complexes with functional thiolato bridges from dialkylation of [Pt2(μ-S)2(P-P)2] [P-P = 2 × PPh3, Ph2P(CH2)3PPh 2]

Abstract

The normally robust monoalkylated complexes [Pt2(-S)(-SR) (PPh3)4]+ can be activated towards further alkylation. Dialkylated complexes [Pt2(-SR)2(P-P) 2]2+ (P-P = 2 × PPh3, Ph 2P(CH2)3PPh2) can be stabilized and isolated by the use of electron-rich and aromatic halogenated substituents R [e.g. 3-(2-bromoethyl)indole and 2-bromo-4′-phenylacetophenone] and 1,3-bis(diphenylphosphino)propane [Ph2P(CH2) 3PPh2 or dppp] which enhances the nucleophilicity of the {Pt2(-S)2} core. This strategy led to the activation of [Pt2(-S)(-SR)(PPh3)4]+ towards R-X as well as isolation and crystallographic elucidation of [Pt2(- SC10H10N)2(PPh3)4] (PF6)2 (2a), [Pt2(-SCH2C(O)C 6H4C6H5)2(PPh 3)4](PF6)2 (2b), and a range of functionalized-thiolato bridged complexes such as [Pt2(-SR) 2(dppp)2](PF6)2 [R = -CH 2C6H5 (8a), -CH2CHCH2 (8b) and -CH2CN (8c)]. The stepwise alkylation process is conveniently monitored by Electrospray Ionisation Mass Spectrometry, allowing for a direct qualitative comparison of the nucleophilicity of [Pt 2(-S)2(P-P)2], thereby guiding the bench-top synthesis of some products observed spectroscopically. © The Royal Society of Chemistry.