Pentamethylcyclopentadienyl iridium dichloride dimer
Chemical compound
From Wikipedia, the free encyclopedia
Pentamethylcyclopentadienyl iridium dichloride dimer is an organometallic compound with the formula [(C5(CH3)5IrCl2)]2, commonly abbreviated [Cp*IrCl2]2 This bright orange air-stable diamagnetic solid is a reagent in organometallic chemistry.[1]
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| Names | |
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| IUPAC name
Di-μ-chloro-bis[chloro(pentamethylcyclopentadienyl)iridium(III)] | |
| Other names
Dichloro(pentamethylcyclopentadienyl)iridium(III) | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.205.779 |
| EC Number |
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PubChem CID |
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| Properties | |
| C20H30Cl4Ir2 | |
| Molar mass | 796.71 g/mol |
| Appearance | orange solid |
| Melting point | >230 °C |
| Dichloromethane, Chloroform | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
The compound has C2h symmetry. Each metal is pseudo-octahedral. The terminal and bridging Ir-Cl bonds have the lengths 2.39 and 2.45 Å, respectively.
Preparation, reactions
Pentamethylcyclopentadienyl iridium dichloride dimer was first prepared by the reaction of hydrated iridium trichloride with hexamethyl Dewar benzene.[2] More conveniently, the compound is prepared by the reaction of hydrated iridium trichloride and pentamethylcyclopentadiene in hot methanol, from which the product precipitates[1]
- 2 Cp*H + 2 IrCl3(H2O)3 → [Cp*IrCl2]2 + 2 HCl + 6 H2O
The Ir-μ-Cl bonds are labile and can be cleaved to give a variety of adducts of the general formula Cp*IrCl2L. Such adducts undergo further substitution to afford cations [Cp*IrClL2]+ and [Cp*IrL3]2+. The chloride ligands can also be replaced by other anions such as carboxylates, nitrite, and azide.
Reduction of [Cp*IrCl2]2 in the presence of CO affords [Cp*Ir(CO)2], which can be decarbonylated to give the unsaturated derivative [Cp*Ir(CO)]2.[3] Treatment of [Cp*IrCl2]2 with borohydride under an atmosphere of H2 gives the iridium(V) derivative Cp*IrH4.
[Cp*IrCl2]2 is a precursor to catalysts for the asymmetric transfer hydrogenation of ketones.[4]
Related compounds
- The 16e monomer (tBu3C5H2)IrCl2[5]
- Pentamethylcyclopentadienyl rhodium dichloride dimer