Thallium(III) complexes of the metalloligands [Pt 2(μ-S) 2(PPh 3) 4] and [Pt 2(μ-Se) 2(PPh 3) 4

Abstract

Reactions of [Pt 2(μ-S) 2(PPh 3) 4] with the diarylthallium(III) bromides Ar 2TlBr [Ar = Ph and p-ClC 6H 4] in methanol gave good yields of the thallium(III) adducts [Pt 2(μ-S) 2(PPh 3) 4TlAr 2] +, isolated as their BPh 4 - salts. The corresponding selenide complex [Pt 2(μ-Se) 2(PPh 3) 4TlPh 2]BPh 4 was similarly synthesised from [Pt 2(μ-Se) 2(PPh 3) 4], Ph 2TlBr and NaBPh 4. The reaction of [Pt 2(μ-S) 2(PPh 3) 4] with PhTlBr 2 gave [Pt 2(μ-S) 2(PPh 3) 4TlBrPh] +, while reaction with TlBr 3 gave the dibromothallium(III) adduct [Pt 2(μ-S) 2(PPh 3) 4TlBr 2] +[TlBr 4] −. The latter complex is a rare example of a thallium(III) dihalide complex stabilised solely by sulfur donor ligands. X-ray crystal structure determinations on the complexes [Pt 2(μ-S) 2(PPh 3) 4TlPh 2]BPh 4, [Pt 2(μ-S) 2(PPh 3) 4TlBrPh]BPh 4 and [Pt 2(μ-S) 2(PPh 3) 4TlBr 2][TlBr 4] reveal a greater interaction between the thallium(III) centre and the two sulfide ligands on stepwise replacement of Ph by Br, as indicated by shorter Tl–S and Pt⋯Tl distances, and an increasing S–Tl–S bond angle. Investigations of the ESI MS fragmentation behaviour of the thallium(III) complexes are reported.