Synthesis and characterisation of mono- and di-nuclear mixed phosphathia complexes of gold(I): crystal structures of [Au(RSC2H4SR)]PF6, [Au(RSC3H6SR)]PF6and [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 AuI in the solid state; Au–P 2.284(7), 2.302(7), Au⋯S 2.899(6), 3.190(7)A. The structure of [Au(RSC3H6SR)]+ shows a very similar aggangement; Au–P 2.279(6), 2.287(6), A, Au⋯S 3.097(5), 3.101(6)A. 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.