Wilkinson's catalyst



Wilkinson's catalyst
IUPAC name Chlorotris(triphenylphosphine)-
rhodium
Other names Rhodium(I) tris-
(triphenylphosphine) chloride,
Wilkinson’s catalyst,
Tris(triphenylphosphine)-
rhodium chloride
Identifiers
CAS number 14694-95-2
EINECS number 238-744-5
RTECS number none
Properties
Molecular formula C54H45ClP3Rh
Molar mass 925.22 g/mol
Appearance red solid
Melting point

245-250 °C

Solubility in water insoluble
Solubility in other solvents benzene
Structure
Coordination
geometry 		square planar
Hazards
Main hazards none
R-phrases none
S-phrases S24/25
Related Compounds
Related compounds IrCl(CO)[P(C6H5)3]2
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Wilkinson's catalyst is the common name for chlorotris(triphenylphosphine)rhodium(I), a Geoffrey Wilkinson who popularlized its use.

Structure and basic properties

The compound is a square planar, 16-electron complex and is usually isolated in the form of a red-violet crystalline solid from the reaction of triphenylphosphine. The synthesis is conducted in refluxing ethanol.[1] Ethanol serves as the reducing agent.

RhCl3(H2O)3 + CH3CH2OH + 3 PPh3 → RhCl(PPh3)3 + CH3CHO + 2 HCl + 3 H2O

Catalytic applications

Wilkinson's catalyst catalyzes the reductive elimination results in extrusion of the alkane product, e.g.:

Other applications of Wilkinson’s catalyst include: catalytic carbonyl compounds in concert with triethylsilane.4

Other reactions of RhCl(PPh3)3

RhCl(Ph3P)3 reacts with CO to give RhCl(CO)(PPh3)2, which is structurally analogous to aldehydes, although the reaction is stoiochiometric:

RhCl(PPh3)3 + RCHO → RhCl(CO)(PPh3)2 + RH + PPh3

Upon stirring in benzene solution, RhCl(PPh3)3 loses PPh3 to give the poorly soluble red-colored species Rh2Cl2(PPh3)4. This conversion demonstrates the lability of the triphenylphosphine ligands.

References

The references in this article would be clearer with a different or consistent style of citation, footnoting, or external linking.
  1. ^ Osborn, J. A.; Jardine, F. H.; Young, J. F.; Wilkinson, G. (1966). "The Preparation and Properties of Tris(triphenylphosphine)halogenorhodium(I) and Some Reactions Thereof Including Catalytic Homogeneous Hydrogenation of Olefins and Acetylenes and Their Derivatives". Journal of the Chemical Society A: 1711 - 1732. doi:10.1039/J19660001711.
  1. (a) A. J. Birch, D. H. Williamson, Organic Reactions 1976, volume 24, page 1ff; (b) B.R. James, Homogeneous Hydrogenation. John Wiley & Sons, New York, 1973.
  2. D. A. Evans, G. C. Fu and A. H. Hoveyda (1988). "Rhodium(I)-catalyzed hydroboration of olefins. The documentation of regio- and stereochemical control in cyclic and acyclic systems". J. Am. Chem. Soc. 110 (20): 6917-6918. doi:10.1021/ja00228a068.
  3. I. Ojima, T. Kogure, Y. Nagai, Tetrahedron Lett. 1972, page 5035.
 
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