Wilkinson's catalyst (chlorido­tris(triphenylphosphine)­rhodium(I)) is a coordination complex of rhodium with the formula [RhCl(PPh3)3], where 'Ph' denotes a phenyl group.

Historically, Wilkinson's catalyst has been a paradigm in catalytic studies leading to several advances in the field such as the implementation of some of the first heteronuclear magnetic resonance studies for its structural elucidation in solution (31P),[3] parahydrogen-induced polarization spectroscopy to determine the nature of transient reactive species,[4] or one of the first detailed kinetic investigation by Halpern to elucidate the mechanism.

In contrast, IrCl(PPh3)3 undergoes cyclometallation to give HIrCl(PPh3)2(PPh2C6H4), a coordinatively saturated Ir(III) complex that is not catalytically active.

[8] Wilkinson's catalyst is usually obtained by treating rhodium(III) chloride hydrate with an excess of triphenylphosphine in refluxing ethanol.

[11][12] The mechanism of this reaction involves the initial dissociation of one or two triphenylphosphine ligands to give 14- or 12-electron complexes, respectively, followed by oxidative addition of H2 to the metal.

[17] RhCl(PPh3)3 reacts with carbon monoxide to give bis(triphenylphosphine)rhodium carbonyl chloride, trans-RhCl(CO)(PPh3)2.