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Pentamethylcyclopentadienyl iridium dichloride dimer

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Pentamethylcyclopentadienyl iridium dichloride dimer
Names
IUPAC name Di-µ-chloro-bis
Other names Dichloro(pentamethylcyclopentadienyl)iridium(III)
Identifiers
CAS Number
ECHA InfoCard 100.205.779 Edit this at Wikidata
Properties
Chemical formula C20H30Cl4Ir2
Molar mass 796.71 g/mol
Appearance orange solid
Melting point >230 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references
Chemical compound

Pentamethylcyclopentadienyl iridium dichloride is an organometallic compound with the formula 2, commonly abbreviated 2 This bright orange air stable diamagnetic solid is a reagent in organometallic chemistry.

Preparation, structure, reactions

The compound has C2h symmetry. Each metal is pseudo-octahedral. It was first prepared by the reaction of hydrated iridium trichloride with hexamethyldewar benzene. More conveniently, iridium trihydrate and pentamethylcyclopentadiene consistently gives the product in both high yield and purity according to this idealized equation:

2 Cp*H + 2 IrCl3(H2O)3 → 2 + 2 HCl + 6 H2O

The two 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 and . The chloride ligands can also be replaced by other anions such as carboxylates, nitrite, and azide.

Reduction of 2 under an atmosphere of CO affords the dicarbonyl Cp*Ir(CO)2], which can be decarbonylated to give the unsaturated derivative 2. Treatment of 2 with borohydride under an atmosphere of H2 gives the iridium(V) derivative Cp*IrH4.

2 is a precursor to catalysts for the asymmetric transfer hydrogenation of ketones.

References

  1. ^ White, C.; Yates, A.; Maitlis, P. M. (1992). "(η-Pentamethylcyclopentadienyl)Rhodium and -Iridium Compounds". Inorganic Syntheses. 29: 228–234. doi:10.1002/9780470132609.ch53. {{cite journal}}: Unknown parameter |DUPLICATE DATA: doi= ignored (help)
  2. Jung W. Kang; K. Moseley; Peter M. Maitlis (1969). "Pentamethylcyclopentadienylrhodium and -iridium halides. I. Synthesis and properties". Journal of the American Chemical Society. 91: 5970. doi:10.1021/ja01050a008.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. R. G. Ball; W. A. G. Graham; D. M. Heinekey; J. K. Hoyano; A. D. McMaster; B. M. Mattson; S. T. Michel (1990). "Synthesis and structure of dicarbonylbis(.eta.-pentamethylcyclopentadienyl)diiridium". Inorganic Chemistry. 29: 2023. doi:10.1021/ic00335a051.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. Ikariya, T.; Blacker, A. J. (2007). "Asymmetric transfer hydrogenation of ketones with bifunctional transition metal-based molecular catalysts". Accounts of Chemical Research. 40 (12): 1300–8. doi:10.1021/ar700134q. ISSN 0001-4842. PMID 17960897. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
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