Synthesis and characterisation of mono- and di-nuclear mixed phosphathia complexes of gold(I): crystal structures of [Au(RSC2H4SR)]PF6, [Au(RSC3H6SR)]PF6 and [Au2(RSC2H4SR)2]Cl2·4CH2Cl2(R = Ph2PC2H4)

Abstract

Mononuclear gold(I) complexes of two linear P₂S₂ donor ligands, [AuL]PF₆[L = RSC₂H₄SR or RSC₃H₆SR (R = Ph₂PC₂H₄)] have been prepared by reaction of [AuCl(tht)](tht = tetrahydrothiophene) with L and TIPF₆ in MeCN solution. The crystal structure of [Au(RSC₂H₄SR)]⁺ shows a primary P₂-donor set with additional long-range thioether interactions giving a distorted linear geometry around Au^I in the solid state; Au–P 2.284(7), 2.302(7), Au⋯S 2.899(6), 3.190(7)Å. The structure of [Au(RSC₃H₆SR)]⁺ shows a very similar aggangement; Au–P 2.279(6), 2.287(6), Å, Au⋯S 3.097(5), 3.101(6)Å. The non-conducting binuclear species [Au₂Cl₂L] were obtained by reaction of [AuCl(tht)] with L in a 2 : 1 molar ratio in CH₂Cl₂ solution, while a 1 : 1 [AuCl(tht)]: RSC₂H₄SR ratio yielded the unusual species [Au₂(RSC₂H₄SR)₂]Cl₂, the crystal structure of which shows a linear P₂-donor set at each Au, giving a helical cavity which contains a Cl^– anion. All complexes have been characterised by IR, ¹H and ³¹P NMR spectroscopies, FAB mass spectrometry and microanalyses.