Rhodium(II) trifluoroacetate
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Names | |
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Other names
Dirhodium tetrakis(trifluoroacetate, rhodium(II) trifluoroacetate dimer
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.159.403 |
EC Number |
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PubChem CID
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Properties | |
C8F12O8Rh2 | |
Molar mass | 657.872 g·mol−1 |
Appearance | green solid |
Hazards | |
GHS labelling:< | |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Rhodium trifluoroacetate is the chemical compound with the formula Rh2(O2CCF3)4. It is used as a catalyst in the synthesis of some organic compounds.[1] The compound and its derivatives have been extensively characterized by X-ray crystallography. It adopts the Chinese lantern structure seen for many dimetal carboxylate complexes. This structure accommodates a Rh-Rh bond, the existence of which explains the diamagnetism of this Rh(II) species. The Rh-Rh distance is 238 pm.[2]
The anhydrous complex is a green volatile solid. It is prepared by dissolving rhodium(II) acetate in hot trifluoroacetic acid:[3]
- Rh2(O2CCH3)4 + 4 HO2CCF3 → Rh2(O2CCF3)4 + 4 HO2CCH3
This reaction expels acetic acid. The Rh-Rh bond is retained.
Reactions
[edit]Rhodium(II) trifluoroacetate forms adducts, often with 2:1 stoichiometry, with a variety of Lewis bases. The bases bind at the "axial" positions on each of the two Rh(II) center:
- Rh2(O2CCF3)4 + 2 L → Rh2(O2CCF3)4L2 (L = CO, RCN, R2SO, R3P, ...)
Rhodium(II) trifluoroacetate binds even very weak bases, moreso than does rhodium(II) acetate. It even forms adducts with hexamethylbenzene and with S8.[4]
Rhodium(II) trifluoroacetate catalyzes cyclopropanation of alkenes by diazo compounds:[1] RCH=CR'H + CH3CH2O2CCH(N2) → cyclo−(RCH)(R'CH)(CH3CH2O2CCH) + N2
References
[edit]- ^ a b Doyle, Michael P.; Davies, Huw M. L.; Manning, James R.; Yu, Yang (2018). "Dirhodium(II) tetrakis(trifluoroacetate)". EEROS. doi:10.1002/047084289X.rd461.pub2 (inactive 2024-07-05).
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: CS1 maint: DOI inactive as of July 2024 (link) - ^ Cotton, F. Albert; Dikarev, Evgeny V.; Feng, Xuejun (1995). "Unligated Dirhodium Tetra(trifluoroacetate): Preparation, Crystal Structure and Electronic Structure". Inorganica Chimica Acta. 237 (1–2): 19–26. doi:10.1016/0020-1693(95)04662-S.
- ^ Felthouse, Timothy R. (1982). "The Chemistry, Structure, and Metal-Metal Bonding in Compounds of Rhodium(II)". Progress in Inorganic Chemistry. Vol. 29. pp. 73–166. doi:10.1002/9780470166307.ch2. ISBN 978-0-471-09370-1.
- ^ Cotton, F. Albert; Dikarev, Evgeny V.; Petrukhina, Marina A. (2001). "Neutral Cyclooctasulfur as a Polydentate Ligand: Supramolecular Structures of [Rh2(O2CCF3)4]n(S8)m (N:m=1:1, 3:2)". Angewandte Chemie International Edition. 40 (8): 1521–1523. doi:10.1002/1521-3773(20010417)40:8<1521::AID-ANIE1521>3.0.CO;2-M.