Chloro(triphenylphosphine)gold(I) or triphenylphosphinegold(I) chloride is a coordination complex with the formula (Ph<sub>3</sub>P)AuCl. This colorless solid is a common reagent for research on gold compounds.
The complex is prepared by reducing chloroauric acid with triphenylphosphine in 95% ethanol:
Chloro(triphenylphosphine)gold(I) can also be prepared by treating (dimethyl sulfide)gold(I) chloride (((CH<sub>3</sub>)<sub>2</sub>S)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 P2<sub>1</sub>2<sub>1</sub>2<sub>1</sub> with a = 12.300(4) ÃÂ , b = 13.084(4) ÃÂ , c = 10.170(3) ÃÂ with Z = 4 formula units per unit cell.
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<sup>âÂÂ</sup> = SbF<sub>6</sub><sup>âÂÂ</sup>, BF<sub>4</sub><sup>âÂÂ</sup>, TfO<sup>âÂÂ</sup>, or Tf<sub>2</sub>N<sup>âÂÂ</sup>) to generate a weakly bound Ph<sub>3</sub>PAuâÂÂX complex. Among these, only the bistriflimide complex Ph<sub>3</sub>PAuNTf<sub>2</sub> can be purified. The nitrate complex Ph<sub>3</sub>PAuONO<sub>2</sub> and the oxonium species [(Ph<sub>3</sub>PAu)<sub>3</sub>O]<sup>+</sup>[BF<sub>4</sub>]<sup>âÂÂ</sup> are also prepared from the chloride.
Triphenylphosphinegold(I) chloride is an entry reagent for organogold chemistry. The methyl complex Ph<sub>3</sub>PAuMe is prepared from triphenylphosphinegold(I) chloride by transmetalation with a Grignard reagent. Further treatment of Ph<sub>3</sub>PAuMe with methyllithium displaces the phosphine ligand and generates lithium dimethylaurate.