Tris(pentafluorophenyl)gold(III) complexes

Abstract

The preparation of [Au(C₆F₅)₃(tht)](tht = tetrahydrothiophen) by oxidation of [Au(C₆F₅)(tht)] with [Tl(C₆F₅)₂Cl] is described. Displacement of tht by other neutral or anionic unidentate ligands leads to the synthesis of [Au(C₆F₅)₃L][L = NH₃, py, PMePh₂, P(OPh)₃, AsPh₃, SbPh₃ or CNC₆H₄Me-p] or Q[Au(C₆F₅)₃X][Q = NEt₄, NBu₄, PPh₃(CH₂Ph), or N(PPh₃)₂; X = Cl, I, SCN, or N₃]. The compound [Au(C₆H₅)₃(CNC₆H₄Me-p)] adds amines to give the gold(III)–carbene complexes [Au(C₆F₅)₃{C(NHC₆H₄Me-p)(NR₂)}](NR₂= NHC₆H₄Me-p, NEt₂, or NHCH₂CH₂NH₂). The reaction of the compound [Au(C₆F₅)₃(tht)] with potentially bidentate ligands takes two different courses. (a)o-Phenylenebis(dimethylarsine)(pdma) and 1,2-bis(diphenylphosphino)methane (dppm) give four-co-ordinated complexes, in which the ligands are unidentate; the pdma complex has inequivalent methyl hydrogens at low temperature (¹H n.m.r.) and the dppm complex inequivalent P atoms (³¹P n.m.r.). An X-ray structure of the pdma complex confirms four-co-ordination in the solid state; space group P2₁/n, a= 10.796(3), b= 17.347(6), c= 16.275(5)Å, β= 94.47(3)°, Z= 4, R= 0.058 for 3 357 reflections. (b) 1,2-Bis(diphenylphosphino)ethane (dppe) acts as a bridging ligand leading to the formation of [(C₆F₅)₃Au(µ-dppe)Au(C₆F₅)₃]. Similar reactions starting from [Au(C₆F₅)(2,4,6-C₆F₃H₂)2(tht)] lead to the compounds [Au(C₆F₅)(2,4,6-C₆F₃H₂)₂(PPh₃)] or [NBu₄][Au(C₆F₅)(2,4,6-C₆F₃H₂)₂Br]. The arylation of [Au(C₆F₅)₃Cl]^– or [Au(C₆F₅)(2,4,6-C₆F₃H₂)₂Br]^– with Ag(C₆F₅) leads to [Au(C₆F₅)₄]^– and [Au(C₆F₅)₂(2,4,6-C₆F₃H₂)₂]^– respectively.