Mixed-chalcogenide diplatinum complexes; an investigation of ligand exchange processes using ESI mass spectrometry

Abstract

Routes to mixed-chalcogen diplatinum complexes have been explored using Electrospray Ionisation Mass Spectrometry (ESI-MS) as a powerful technique to probe reaction solutions on the microscale. Exchange reactions of binuclear platinum(II) complexes [Pt2(µ-E)2(PPh3)4] (E=S, 1; Se, 2) with each other, or reactions with the elemental chalcogens [viz. complex 1 with Se, and complex 2 with S8] all had limited success in forming the mixed species [Pt2(μ-S)(μ-Se)(PPh3)4]. Reactions of complex 1 with Ph2Se2 and 2 with Ph2S2 resulted in the ESI MS detection of novel arylated mixed-chalcogenide complexes [Pt2(µ-S)(µ-SePh)(PPh3)4]+ and [Pt2(µ-Se)(µ-SPh)(PPh3)4]+, respectively. The analogous reactions of 1 and 2 with diaryl ditellurides R2Te2 (R=Ph, p-EtOC6H4) resulted in the ESI MS detection of the trinuclear aggregates [{Pt(PPh3)}3(µ3-E)(µ-TeR)3]+ and the mixed-chalcogenide complexes [Pt2(µ-E)(µ-TeR)(PPh3)4]+ (E=S, Se; R=Ph, p-EtOC6H4). The compound [{Pt(PPh3)}3(µ3-Se)(µ-TePh)3]PF6 was synthesised on the macroscopic scale, and characterised by elemental analysis and a single-crystal X-ray diffraction study.