Advanced Topic 701 of 1102 Inorganic Chemistry
Wilkinson's Catalyst
A rhodium complex that catalyzes hydrogenation of alkenes.
In-depth explanation of Wilkinson's Catalyst
Wilkinson's catalyst, RhCl(PPh3)3, is a square planar rhodium complex that hydrogenates alkenes to alkanes at room temperature and atmospheric pressure. The cycle begins with loss of one phosphine to open a site, followed by oxidative addition of H2 to rhodium. The alkene binds and inserts into a rhodium-hydride bond, and reductive elimination releases the alkane and regenerates the catalyst. The complex reduces less hindered alkenes faster and leaves many other functional groups untouched. Geoffrey Wilkinson shared the 1973 Nobel Prize in Chemistry.
Going deeper: Wilkinson's Catalyst
Key ideas: RhCl(PPh3)3, a 16-electron square planar Rh(I) complex used to hydrogenate alkenes homogeneously at 1 atm H2 and room temperature. Cycle: oxidative addition of H2 gives Rh(III) dihydride, 18 electrons; ligand loss; alkene coordination; migratory insertion into Rh-H; reductive elimination of alkane regenerates Rh(I). Hydrogenates terminal and less hindered alkenes faster; leaves arenes and carbonyls. Chiral phosphines make asymmetric hydrogenation possible.
Common mistakes and connections: Students count Rh as +3 because of the cycle; the starting state is +1, d8. Addition of H2 is syn on the same face, hence cis hydrogenation. The catalyst is homogeneous, unlike Pd/C. Steps shift 16 to 18 electrons, as the 18-electron rule predicts. Links to oxidative addition, catalysis and stereochemistry of hydrogenation.
Visualization of Wilkinson's Catalyst
Wilkinson's catalyst RhCl(PPh3)3 hydrogenates alkenes by oxidative addition of H2, alkene insertion and reductive elimination; addition to the double bond is shown. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Hydrogen and cyclohexene are converted to cyclohexane in the presence of Wilkinson's catalyst.
Frequently asked questions about Wilkinson's Catalyst
What is Wilkinson's Catalyst?
A rhodium complex that catalyzes hydrogenation of alkenes.
Is Wilkinson's Catalyst a beginner, intermediate or advanced topic?
Wilkinson's Catalyst is a advanced topic in Inorganic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Wilkinson's Catalyst?
Study these earlier topics in Inorganic Chemistry first: Eighteen Electron Rule, Ferrocene, Zeigler-Natta Catalysts.
What comes after Wilkinson's Catalyst?
The next topics in Inorganic Chemistry are Bioinorganic Chemistry and Hemoglobin.
Can I practise Wilkinson's Catalyst with quizzes?
Yes. The interactive lesson includes a self-check question on Wilkinson's Catalyst, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Wilkinson's Catalyst fits in Inorganic Chemistry
Wilkinson's Catalyst is topic 86 of 113 in Inorganic Chemistry.