Stepwise Sulfuration of the Terminal Phosphido Complex trans‐[PtCl(PHCy2)2(PCy2)]: Synthesis of [Pt(κ2S,S′‐PS2Cy2)(PHCy2)2]Cl and [Pt(κ2S,S′‐PS2Cy2){κP‐P(S)Cy2}(PHCy2)] and Crystal Structure of [Pt(κ2‐S,S‐PCy2S2)(κ‐S‐PCy2S2)(PHCy2)

Abstract

AbstractThe terminal phosphido complex trans‐[PtCl(PHCy2)2(PCy2)] (1) has been prepared, exploiting the reversibility of the reaction with HCl, by action of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) on [PtCl(PHCy2)3]Cl, and its reactivity towards elemental sulfur studied. The first product obtained by reaction of 1 with 1 equiv. of sulfur is trans‐[PtCl(PHCy2)2{κP‐P(S)Cy2}] (2), which rapidly isomerises in halogenated solvents into cis‐[PtCl(PHCy2)2{κP‐P(S)Cy2}] (3). Further addition of sulfur causes the formation of a mixture of [Pt(κ2S,S′‐PS2Cy2)(PHCy2)2]Cl (4) and [Pt(κ2S,S′‐PS2Cy2){κP‐P(S)Cy2}(PHCy2)] (5), which could be selectively synthesised; the first upon sulfuration of pure 3 and the second by reaction of 4 with 1 equiv. of sulfur in the presence of DBU. Complex 5 can be further sulfurated to [Pt(κ2S,S′‐PCy2S2)(κS‐PCy2S2)(PHCy2)] (6), which is fluxional in solution and was also characterised by single‐crystal X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)