The synthesis of palladium-gold and platinum-gold bimetallic complexes based upon bis(diphenylarsino)methane: Crystal structure of trans-[Pd(mu-Ph(2)AsCH(2)AsPh(2)AuCl)(2)Cl-2]center dot xCH(2)Cl(2)

The reaction of trans-[M(eta(1)-Ph(2)AsCH(2)AsPh(2))(2)Cl-2] (M = Pd or Pt) with Au(tht)Cl (tht = tetrahydrothiophen) formed trans-[M(mu-Ph(2)AsCH(2)AsPh(2)AuCl)(2)Cl-2], from which the corresponding bromides were made by reaction with LiBr. Oxidative addition of the appropriate dihalogen formed trans-[M(mu-Ph(2)AsCH(2)AsPh(2)AuX(3))(2)X(n)] (M = Pd, n = 2; M = Pt, n = 4). The structure of the complex trans-[Pd(mu-Ph(2)As CH(2)AsPh(2)AuCl)(2)Cl-2]. xCH(2)Cl(2) has been determined and shown to contain trans square planar palladium atoms [Pd-Cl 2.291 (av), Pd-As 2.416(2), 2.400(2) Angstrom]. Each bis(diphenylarsino)methane ligand coordinates to palladium and gold [As-Au 2.331(2), 2.340(2) Angstrom], but there are no significant Pd Au interactions. The ligand Me(2)AsCH(2)AsMe(2) formed only insoluble, probably polymeric, 1.1 complexes [{MCl(2)(Me(2)AsCH(2)AsMe(2))}(n)], whilst reaction of [PdCl2(Ph(2)SbCH(2)SbPh(2))(2)] with [Au(tht)Cl] produced [PdCl2 (Ph(2)SbCH(2)SbPh(2))](2) and [ClAu(Ph(2)SbCH(2)SbPh(2))AuCl].