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Rhodium(II) acetate

Rhodium (II) Acetate
Systematic name Rhodium (II) acetate
Other names Dirhodium tetraacetate,
Rhodium diacetate dimer,
Molecular formula C8H16O10Rh2 (dihydrate)
Molar mass 441.99 g/mol
Appearance Emerald green powder
CAS number 15956-28-2
Density and phase 1.126 g/cm3
Solubility in water soluble
Other solvents polar organic solvents
Melting point >100 °C
Boiling point decomposes
Crystal structure monoclinic
Dipole moment 0 D
MSDS Coleparmer MSDS
Hazard symbols XI
NFPA 704
Flash point low flammability
R/S statement R: 36/38
S: 15, 26, 28A, 37/39
RTECS number VI9361000
Related compounds Copper(II) acetate
Chromium(II) acetate
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Rhodium(II) acetate is the chemical compound with the formula Rh2(AcO)4, where AcO- is the acetate group (CH3CO2). This emerald green powder is a catalyst for cyclopropanation of alkenes. It is also used as catalyst for insertion into C-H and X-H bonds(X = N/S/O) and for ylide formation for organic syntheses.



Rhodium(II) acetate is usually prepared by the heating hydrated rhodium(III) chloride in acetic acid (CH3COOH):[1] Rhodium(II) acetate dimer undergoes ligand exchange, the replacement of the acetate group by other carboxylates and related groups.[2]

Rh2(OAc)4 + 4 HO2Y → Rh2(O2Y)4 + 4 HOAc

Structure and Properties


The structure of rhodium(II) acetate freatures a pair of rhodium atoms, each with octahedral molecular geometry, defined by four acetate oxygen atoms, a water ligand, and a Rh-Rh bond (2.39 Å.[3]. Copper(II) acetate and chromium(II) acetate adopt similar structures.

Chemical Properties

The application of dirhodium tetraacetate to organic synthesis was pioneered by Teyssie and co-workers.[4] A extensive library of successful transformations rapidly evolved, ranging from Rh(II)-catalyzed OH and NH insertions to cyclopropanation of olefins[5] and aromatic systems.[6] Nowadays, it is used mainly as a catalyst. It can help distinguish between ribonucleosides and deoxynucleosides by binding selectively to ribonucleosides at their 2' and 3' OH groups[7]. Rhodium(II) acetate dimer, compared to copper(II) acetate, is more reactive and useful in differentiating ribonucleosides and deoxynucleosides because it is soluble in aqueous solution like water whereas copper(II) acetate only dissolves in non-aqueous solution.

Selected catalytic reactions

1. Cyclopropanation

through the decomposition of diazocarbonyl compounds, the intra- and inter­molecular cyclopropanation reactions occurs.

2. Aromatic cycloaddition

Rhodium acetate is a very efficient catalyst for two-component ­cycloaddition as well as three-component 1,3-dipolar cycloaddition reactions.

3. C-H insertion

Rh(II)-catalyzed regioselective intramolecular and regiospecific intermolecular C-H insertion into aliphatic and aromatic C-H bonds is an useful method for the synthesis of a ­diverse range of organic compounds.

4. Oxidation of alcohols

Allylic and benzylic alcohols were oxidized to the corresponding carbonyl compounds using tert-butyl hydroperoxide in ­stoichiometric amounts and Rh2(OAc)4 as catalyst in dichloromethane at ambient temperature.

5. X-H insertion (X = N/S/O)

Rh(II) carbenoid reacts with amines, alcohols or thiols to yield the product of a formal intra- or intermolecular X-H bond (X = N/O/S) insertion via the formation of an ylide intermediate.


  1. ^ G. A. Rempel, P. Legzdins, H. Smith, G. Wilkinson, "Tetrakis(Acetato) Dirhodium (II) and Similar Carboxylato Compounds" Inorganic Syntheses, volume 13, pp 90-91. ISBN: 9780470131725
  2. ^ Doyle, M. P. In Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I., Ed.;Wiley: New York, 2000; Chapter 5.
  3. ^ Cotton, F. A.; DeBoer, B. G.; Laprade, M. D.; Pipal, J. R.; Ucko, D. A. Acta Crystallographica 1971, B27, 1664.
  4. ^ Paulissenen R.; Reimlinger, H.; Hayez, E.; Hubert, A. J.; Teyssie, P. Tetrahedron Letters 1973, volume 14: 2233
  5. ^ Hubert, A. J.; Feron A.; Warin, R. Teyssie, P., Tetrahedron Letters 1976, volume 17, pp.1317
  6. ^ Anciaux, A. J.; Demonceau, A.; Hubert, A. J.; Noels, A. F.; Petiniot, N.; Teyssie, P. Journal of the Chemical Society, Chem. Commun. 1980, 765
  7. ^ Berger, N. A.; Tarien, E.; Eichhorn, G. L. Nature New Biology 1972, volume 239, pp. 237.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Rhodium(II)_acetate". A list of authors is available in Wikipedia.
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