Ruthenium(III) chloride
Encyclopedia : R : RU : RUT : Ruthenium(III) chloride
| Ruthenium(III) chloride | |
|---|---|
| align="center" | |
| Systematic name | Ruthenium trichloride Ruthenium(III) chloride |
| Molecular formula | RuCl3·xH2O |
| Molar mass | 207.43 g/mol (anhydrous) 261.47 g/mol (trihydrate) |
| CAS number | [14898-67-0][link] (hydrate) |
| Density | 3.90 g/cm3 (anhydrous) |
| Solubility (water) | Soluble |
| Melting point | >500 °C (decomp.) |
| Structure | |
| Coordination geometry | octahedral |
| Crystal structure | CrCl3 |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | probably toxic |
| R/S statement (trihydrate) | R: 34 S: 26-27-36/37/39 |
| RTECS number | VM2650000 |
| Supplementary data page | |
| Structure and properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | RuBr3(H2O)x |
| Other cations | RhCl3 FeCl3 |
| Related compounds | RuO4 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) [Chemical infoboxInfobox disclaimer and references] | |
Ruthenium(III) chloride is RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·xH2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a varying proportion of water of crystallization, often approximating to a trihydrate, is a commonly used starting material in ruthenium chemistry.
Contents
Preparation and properties
Well characterized but rarely used are the anhydrous forms of ruthenium(III) chloride. This crystalline material is usually prepared by heating powdered ruthenium metal to 700 °C under a 4:1 mixture of chlorine and carbon monoxide: the product is carried by the gas stream and crystallises on cooling.[#endnote_Remy] RuCl3 exists is two crystalline modifications. The black α-form adopts the CrCl3-type structure with long Ru-Ru contacts of 3.46 Å. The dark brown metastable β-form crystallizes in a hexagonal cell; this form consists of infinite chains of face-sharing octahedra with Ru-Ru contacts of 2.83 Å. The β-form is irreversibly converted to the α-form at 450–600 °C.RuCl3 vapour decomposes into the elements at high temperatures (as do all compounds!): the enthalpy change at 750 °C (1020 K), ΔdissH1020 has been estimated as +240 kJ/mol.
Coordination chemistry
As the most common ruthenium compound in the laboratory, RuCl3·xH2O is a precursor to many hundreds of chemical compounds. The noteworthy property of ruthenium complexes, chlorides and otherwise is the existence of multiple oxidation states, many of which are kinetically inert. All second and third-row transition metals form exclusively low spin complexes, whereas ruthenium is special in the stability of adjacent oxidation states, especially Ru(II), Ru(III) (as in the parent RuCl3·xH2O) and Ru(IV).Illustrative complexes derived from \"ruthenium trichloride\"
Some examples include:- RuCl2(PPh3)3, a chocolate-colored, benzene-soluble species, which in turn is also a versatile starting material. It arises approximately as follows:
- 2RuCl3·xH2O + 7 PPh3 → 2 RuCl2(PPh3)3 + OPPh3 + 5 H2O + 2 HCl
- Ru(bipy)3Cl2, an intensely luminescent salt with a long-lived excited state, arising as follows:
- [RuCl2(C5Me5)]2, arising as follows:
- Ru(C5H7O2)3, a red, benzene-soluble coordination complex arising as follows:
Carbon monoxide derivatives
RuCl3(H2O)x reacts with carbon monoxide under mild conditions. In contrast iron chloride does not react with CO. CO reduces the red-brown trichloride to yellowish Ru(II) species. Specifically, exposure of an ethanol solution of RuCl3(H2O)x to 1 atm of CO gives, depending on the specific conditions, [Ru2Cl4(CO)4], [Ru2Cl4(CO)4]2-, and [RuCl3(CO)3]-. Addition of ligands (L) to such solutions gives Ru-Cl-CO-L compounds (L = PR3). Reduction of these carbonylated solutions with Zn affords the orange triangular cluster [Ru3(CO)12.- :3 RuCl3·xH2O + 4.5 Zn + 12 CO (high pressure) → Ru3(CO)12 + 3 H2O + 4.5 ZnCl2
Sources
- Gmelins Handbuch der Anorganischen Chemie
References
- ↑ Remy, H.; Kühn, M. (1924). Z. Anorg. Chem. 137:374.
- Bennett, M. A.; Huang, T. N.; Matheson, T. W. and Smith, A. K., "(h6-Hexamethylbenzene)ruthenium complexes", Inorganic Syntheses, 1982, volume 21, 74-8.
- T. Ikariya, K. Murata, R. Noyori "Bifunctional Transition Metal-Based Molecular Catalysts for Asymmetric Syntheses" Organic Biomolecular Chemistry, 2006, volume 4, 393–406
Further reading
- Carlsen, P. H. J. et al. (1981). J. Org. Chem. 46:3936. (catalyst for oxidation reactions)
- Gore, E. S. (1983). Platinum Met. Rev. 27:111. (review)
- Cotton, S. A. "Chemistry of Precious Metals," Chapman and Hall (London): 1997. ISBN 0751404136
- Hill, A. F. ""Simple" Ruthenium Carbonyls of Ruthenium: New Avenues from the Hieber Base Reaction", Angewandte Chemie International Editiion, 2000, volume 39, pages 130-134.
External links
- For a full list of external links to MSDSs, spectroscopic data, commercial chemicals suppliers etc. for this compound, see [Chemical sources].
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.