Synthesis and characterization of gold adducts of [M(tppme)(P3)][M = Co, Rh, or Ir; tppme = 1,1,1-tris(diphenylphosphinomethyl)ethane]. X-Ray crystal structures of [Au{M(tppme)(P3)}2]PF6(M = Co, Rh, or Ir)

Abstract

Treatment of a dichloromethane solution of [M(tppme)(P₃)][M = Co, Rh, or Ir; tppme = 1,1,1-tris(diphenylphosphinomethyl)ethane] with the complexes [AuCl(PR₃)](R = Me or Ph) and [Au₂Cl₂{Ph₂P(CH₂)_nPPh₂}](n= 1 or 2) in the presence of TlPF₆ invariably affords the compounds [Au{M(tppme)(P₃)}₂] PF₆·solvent (M = Co, Rh, or Ir). X-Ray crystallographic analyses of the three isomorphous compounds showed that the gold atom is bound to two pairs of phosphorus atoms belonging to the P₃ units of two [M(tppme)(P₃)] fragments; the gold atom has a co-ordination geometry intermediate between tetrahedral and square planar. The unexpected elimination of the phosphane ligand from the gold fragments and the lengthening of the P–P bonds in which insertion of gold occurs are indicative of significant interaction between the gold atom and the MP₃ clusters.