Triphenylarsine is the chemical compound with the formula As(C6H5)3. This organoarsenic compound, often abbreviated AsPh3, is a colorless crystalline solid that is used as a ligand and a reagent in coordination chemistry and organic synthesis. The molecule is pyramidal with As-C distances of 1.942–1.956 Å and C-As-C angles of 99.6–100.5°.[1]
This compound is prepared by the reaction of arsenic trichloride with chlorobenzene using sodium as the reducing agent:[2]
AsCl3 + 3 PhCl + 6 Na → AsPh3 + 6 NaCl
Reaction of triphenylarsine with lithium gives lithium diphenylarsenide:[3]
AsPh3 + 2 Li → LiAsPh2 + LiPh
Triphenylarsine is the precursor to tetraphenylarsonium chloride, [AsPh<sub>4</sub>]Cl, a popular precipitating agent.[2]
AsPh3 forms metal complexes with metals. Most are analogues of the corresponding triphenylphosphine derivatives. Examples include [IrCl(CO)(AsPh<sub>3</sub>)]2, [RhCl(AsPh<sub>3</sub>)<sub>3</sub>], and [Fe(CO)<sub>4</sub>(AsPh<sub>3</sub>)].[4]
Tetraphenylarsonium chloride is prepared from triphenylarsine:[5]
(C6H5)3As + Br2 → (C6H5)3AsBr2
(C6H5)3AsBr2 + H2O → (C6H5)3AsO + 2 HBr
(C6H5)3AsO + C6H5MgBr → (C6H5)4AsOMgBr
(C6H5)4AsOMgBr + 3 HCl → (C6H5)4AsCl.HCl + MgBrCl
(C6H5)4AsCl.HCl + NaOH → (C6H5)4AsCl + NaCl + H2O