Pentamethylcyclopentadienyl iridium dichloride dimer

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]

Pentamethylcyclopentadienyl iridium dichloride dimer

Names
IUPAC name Di-μ-chloro-bis[chloro(pentamethylcyclopentadienyl)iridium(III)]
Other names Dichloro(pentamethylcyclopentadienyl)iridium(III)
Identifiers
CAS Number	12354-84-6 Y
3D model (JSmol)	Interactive image
ChemSpider	26583490
ECHA InfoCard	100.205.779
EC Number	680-648-4
PubChem CID	131674877
UNII	6OY4UUC534
InChI InChI=1S/2C10H16.4ClH.2Ir/c2*1-6-7(2)9(4)10(5)8(6)3;;;;;;/h2*6H,1-5H3;4*1H;;/p-4 Key: PGQVOTGCKISIMD-UHFFFAOYSA-J
SMILES c1(C)=c(C)c(C)=c(C)c1(C)[Ir](Cl)(Cl1)Cl[Ir](Cl)1C1(C)C(C)=C(C)C(C)=C1C
Properties
Chemical formula	C20H30Cl4Ir2
Molar mass	796.71 g/mol
Appearance	orange solid
Melting point	>230 °C
Solubility in water	Dichloromethane, Chloroform
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Structure

The compound has C_2h 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