Chloro(triphenylphosphine)gold(I) or triphenylphosphinegold(I) chloride is a coordination complex with the formula (Ph3P)AuCl. This colorless solid is a common reagent for research on gold compounds.
Preparation and structure The complex is prepared by reducing chloroauric acid with triphenylphosphine in 95% ethanol: (Ph = phenyl, C6H5)
Chloro(triphenylphosphine)gold(I) can also be prepared by treating (dimethyl sulfide)gold(I) chloride (((CH3)2S)AuCl) with triphenylphosphine.
The complex adopts a linear coordination geometry, which is typical of most gold(I) compounds. It crystallizes in the orthorhombic space group P212121 with a = 12.300(4) Å, b = 13.084(4) Å, c = 10.170(3) Å with Z = 4 formula units per unit cell.
Reactivity Triphenylphosphinegold(I) chloride is a precursor to gold(I) catalyst used in organic synthesis. Typically, it is treated with silver(I) salts of weakly coordinating anions (e.g., X– = SbF6–, BF4–, TfO–, or Tf2N–) to generate a weakly bound Ph3PAu–X complex. Among these, only the bistriflimide complex Ph3PAuNTf2 can be purified. The nitrate complex Ph3PAuONO2 and the oxonium species [(Ph3PAu)3O]+[BF4]– are also prepared from the chloride.A. M. Mueting, B. D. Alexander, P. D. Boyle, A. L. Casalnuovo, L. N. Ito, B. J. Johnson, L. H. Pignolet "Mixed-Metal-Gold Phosphine Cluster Compounds" Inorganic Syntheses, 1992, Volume 29, Pages 279–298, 2007.
Triphenylphosphinegold(I) chloride is an entry reagent for organogold chemistry. The methyl complex Ph3PAuMe is prepared from triphenylphosphinegold(I) chloride by transmetalation with a Grignard reagent. Further treatment of Ph3PAuMe with methyllithium displaces the phosphine ligand and generates lithium dimethylaurate.
References