Stable diplatinum complexes with functional thiolato bridges from dialkylation of [Pt2(μ-S)2(P–P)2] [P–P = 2 × PPh3, Ph2P(CH2)3PPh2]?

Dalton Transactions Pub Date: 2007-08-02 DOI: 10.1039/B707526J

Abstract

The normally robust monoalkylated complexes [Pt2(μ-S)(μ-SR)(PPh3)4]+ can be activated towards further alkylation. Dialkylated complexes [Pt2(μ-SR)2(P–P)2]2+ (P–P = 2 × PPh3, Ph2P(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(μ-S)2} core. This strategy led to the activation of [Pt2(μ-S)(μ-SR)(PPh3)4]+ towards R–X as well as isolation and crystallographic elucidation of [Pt2(μ-SC10H10N)2(PPh3)4](PF6)2 (2a), [Pt2(μ-SCH2C(O)C6H4C6H5)2(PPh3)4](PF6)2 (2b), and a range of functionalized-thiolato bridged complexes such as [Pt2(μ-SR)2(dppp)2](PF6)2 [R = –CH2C6H5 (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 [Pt2(μ-S)2(P–P)2], thereby guiding the bench-top synthesis of some products observed spectroscopically.

Graphical abstract: Stable diplatinum complexes with functional thiolato bridges from dialkylation of [Pt2(μ-S)2(P–P)2] [P–P = 2 × PPh3, Ph2P(CH2)3PPh2]
Recommended Literature