Tris(pentafluorophenyl)gold(III) complexeS

Resumo

The preparation of [Au(C 6F 5) 3(tht)] (tht = tetrahydrothiophen) by oxidation of [Au(C 6F 5)(tht)] with [Tl(C 6F 5) 2Cl] is described. Displacement of tht by other neutral or anionic unidentate ligands leads to the synthesis of [Au(C 6F 5) 3L] [L = NH 3, py, PMePh 2, P(OPh) 3, AsPh 3, SbPh 3 or CNC 6H 4Me-p] or Q[Au(C 6F 5) 3X] [Q = NEt 4, NBu 4, PPh 3(CH 2Ph), or N(PPh 3) 2; X = Cl, I, SCN, or N 3]. The compound [Au(C 6H 5) 3(CNC 6H 4Me-p)] adds amines to give the gold(III)-carbene complexes [Au(C 6F 5) 3{C(NHC 6H 4Me-p)(NR 2)}] (NR 2 = NHC 6H 4Me-p, NEt 2, or NHCH 2CH 2NH 2). The reaction of the compound [Au(C 6F 5) 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 P2 1/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 [(C 6F 5) 3Au(μ-dppe)Au(C 6F 5) 3]. Similar reactions starting from [Au(C 6F 5)(2,4,6-C 6F 3H 2)2(tht)] lead to the compounds [Au(C 6F 5)(2,4,6-C 6F 3H 2) 2(PPh 3)] or [NBu 4][Au(C 6F 5)(2,4,6-C 6F 3H 2) 2Br]. The arylation of [Au(C 6F 5) 3Cl] - or [Au(C 6F 5)(2,4,6-C 6F 3H 2) 2Br] - with Ag(C 6F 5) leads to [Au(C 6F 5) 4] - and [Au(C 6F 5) 2(2,4,6-C 6F 3H 2) 2] - respectively.