This is an old revision of this page, as edited by Citation bot 2 (talk | contribs) at 01:00, 16 November 2011 ( Reference to broken doi:10.1038/newbio239237a0 using Template:Cite doi: please fix!). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 01:00, 16 November 2011 by Citation bot 2 (talk | contribs) ( Reference to broken doi:10.1038/newbio239237a0 using Template:Cite doi: please fix!)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Names | |
---|---|
IUPAC name Rhodium (II) acetate | |
Other names
Dirhodium tetraacetate, Tetrakis(acetato)dirhodium(II), Rhodium diacetate dimer, Tetrakis-(mu-acetato)dirhodium | |
Identifiers | |
CAS Number | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.036.425 |
PubChem CID | |
RTECS number |
|
CompTox Dashboard (EPA) | |
InChI
| |
SMILES
| |
Properties | |
Chemical formula | C8H12O8Rh2 |
Molar mass | 441.99 g/mol |
Appearance | Emerald green powder |
Density | 1.126 g/cm |
Melting point | >100 °C |
Boiling point | decomposes |
Solubility in water | soluble |
Solubility in other solvents | polar organic solvents |
Structure | |
Crystal structure | monoclinic |
Coordination geometry | octahedral |
Dipole moment | 0 D |
Hazards | |
NFPA 704 (fire diamond) | 3 0 0 |
Flash point | low flammability |
Related compounds | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is ?) Infobox references |
Rhodium(II) acetate is the chemical compound with the formula Rh2(AcO)4, where AcO is the acetate ion (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.
Preparation
Rhodium(II) acetate is usually prepared by the heating hydrated rhodium(III) chloride in acetic acid (CH3COOH): Rhodium(II) acetate dimer undergoes ligand exchange, the replacement of the acetate group by other carboxylates and related groups.
- Rh2(OAc)4 + 4 HO2Y → Rh2(O2Y)4 + 4 HOAc
Structure and Properties
The structure of rhodium(II) acetate features 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.. 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. A extensive library of successful transformations rapidly evolved, ranging from Rh(II)-catalyzed OH and NH insertions to cyclopropanation of olefins and aromatic systems. 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. 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 a 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.
References
- Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1002/9780470132449.ch16, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1002/9780470132449.ch16
instead. - Doyle, M.P. (2000). "Asymmetric Addition and Insertion Reactions of Catalytically-Generated Metal Carbenes". In Ojima, Iwao (ed.). Catalytic Asymmetric Synthesis (2nd ed.). New York: Wiley. ISBN 0471298050.
{{cite book}}
: Cite has empty unknown parameter:|1=
(help) - Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1107/S0567740871004527, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1107/S0567740871004527
instead. - Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0040-4039(01)87603-6, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1016/S0040-4039(01)87603-6
instead. - Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0040-4039(00)78050-6, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1016/S0040-4039(00)78050-6
instead. - Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1039/C39800000765 , please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1039/C39800000765
instead. - Template:Broken doi
Rhodium compounds | |||
---|---|---|---|
Rh(0) |
| ||
Rh(I) |
| ||
Rh(II) |
| ||
Rh(III) |
| ||
Rh(IV) | |||
Rh(V) | |||
Rh(VI) |