Wilkinson’s catalyst

January 15, 2024
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Wilkinson’s catalyst, formally chloridotris(triphenylphosphine)rhodium(I) [RhCl(PPh3)3], is a coordination complex that catalyzes a wide range of organic reactions, principally the hydrogenation of alkenes and alkynes and hydrofunctionalization reactions across double bonds such as hydroacylation (hydroformylation) and hydrosilylation. It is named for Geoffrey Wilkinson, who won the 1973 Nobel Prize in Chemistry.

Wilkinson, at Imperial College London, published his first papers on rhodium catalysts in 1965. At the Robert A. Welch Foundation Conference on Chemical Research that year, he described the synthesis of the complex, in which rhodium(III) chloride1 (RhCl3) and excess triphenylphosphine2 (PPh3) are heated in ethanol solution. In a second paper, with three coauthors, he elucidated the hydride intermediates formed when RhCl(PPh3)3 catalyzes hydrogenation reactions of unsaturated compounds.

Three years later, Wilkinson, along with D. Evans and J. A. Osborn, described the use of rhodium complex catalysts, including RhCl(PPh3)3, to promote the hydroformylation of alkenes. Overall, Wilkinson and his colleagues wrote 26 papers from 1965 to 1990 on the synthesis, properties, and catalytic behavior of RhCl(PPh3)3 and related complexes.

1. CAS Reg. No. 10049-07-7.
2. CAS Reg. No. 603-35-0.

Wilkinson’s catalyst hazard information*

Hazard class**GHS code and hazard statement
Skin corrosion/irritation, category 2H315—Causes skin irritationChemical Safety Warning
Skin sensitization, category 1H317—May cause an allergic skin reactionChemical Safety Warning

Serious eye damage/eye irritation, category 2A

H319—Causes serious eye irritationChemical Safety Warning

Specific target organ toxicity, single exposure, respiratory tract irritation, category 3

H335—May cause respiratory irritationChemical Safety Warning
Long-term (chronic) aquatic hazard, category 4H413—May cause long-lasting harmful effects to aquatic life

*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Explanation of pictograms.

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1. CAS Reg. No. 172732-68-2.
2. CAS Reg. No. 9001-84-7.

Molecule in the News

Hydrogen cyanide1 (HCN) was the molecule of the week for December 6, 2010. It is, of course, a poisonous gas; but it has many industrial uses.

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1. CAS Reg. No. 74-90-8.

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Wilkinson’s catalyst 
fast facts

CAS Reg. No.14694-95-2
SciFinder nomenclatureRhodium, chlorotris
(triphenylphosphine)-, (SP-4-2)-
Empirical formulaC54H45ClP3Rh
Molar mass925.22 g/mol
AppearanceReda crystals or powder
Melting range245–250 °C
Water solubilityInsoluble

a. May also be red-brown or -yellow.

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