Synthesis of mono-, di-, and tri-nuclear gold complexes containing the (diphenylphosphino)methyldiphenylphosphoniomethanide ligand. Crystal structures of [Au(C6F5)(Ph2PCHPPh2Me)] and [(C6F5)Au{Ph2PCH(PPh2Me)}Au(C6F5)]
Abstract
The precursors [AuRm(Ph2PCH2PPh2Me)]ClO4(Rm= one or three uninegative ligands) react with excess of NaH by deprotonation of the methylene group and simultaneous elimination of the ClO4 anion to give the neutral methanide complexes [AuRm(Ph2PCHPPh2Me)], which are potential C-donor ligands; these react with complexes of AuI, AuIII, or AgI to form di- or tri-nuclear derivatives of the types [RmAu{Ph2PCH(PPh2Me)}AuX](X = Cl or C6F5), [{(C6F5)AuPh2PCH(PPh2Me)}2M]X (M = Au or Ag; X = AuCl2 or ClO4), or [(C6F5)Au{Ph2PCH(PPh2Me)}Au(C6F5)3]. The structure of [Au(C6F5)(Ph2PCHPPh2Me)] has been determined by X-ray diffraction [space group P, a= 8.888(2), b= 13.053(3), c= 14.230(4)Å, α= 103.15(2), β= 107.22(2), γ= 102.28(2)°, R= 0.026 for 4 806 reflections], as has that of [(C6F5)Au{Ph2P[graphic omitted]u(C6F5)][space group P21/n, a= 12.127(3), b= 22.758(6), c= 13.433(3)Å, β= 98.97(2)°, R= 0.051 for 4 798 reflections]. In the methanide moieties the P–C bond lengths are much longer, and the P–C–P angles much smaller, in the latter compound, reflecting the reduced electron delocalisation in the P–C–P system when the methanide C functions as a donor ligand.